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Plato#039;s Republic Republic [Politeia], Plato - Essay. Greek philosophical dialogues, written c. 3857-60 b.c. Regarded as Plato's most important work, the Republic has long been studied as a seminal text of the Western literary and philosophical canon. In this group of philosophical dialogues, Plato uses a conversational prose format to explore the nature of society, seeking to define the peer review form research, characteristics of an ideal society, or republic. Inspired by the teachings of his mentor, Socrates, in the Republic Plato theorizes that the answer to society's ills lies not in reforming political systems but in adopting philosophic principles as guidelines.

To implement and oversee these principles in society, Plato proposes the creation of what he calls ruler philosophers—individuals who will lead society into an ethical existence based on predetermined principles that are expounded in the Republic. Independence In India! In addition to the Republic, Plato, who founded and review form research paper ran an academy in horse business plan, Athens for many years, wrote a number of other dialogues as well as numerous letters. Because of the peer review form paper, influence of the ideas expressed in various dialogues, including the Republic , Plato has come to occupy a key position in the history of western philosophy and is often called the father of philosophic idealism. Additionally, he is lauded as a preeminent prose stylist and the Republic is regarded as one of the most exemplary texts in this genre, praised for its craftsmanship and poetic qualities. A citizen of Athens, Plato was born in independence, approximately 428 b.c. and peer form research lived in essay respect your teachers, a period of political tumult marked by the recent death of the great Athenian statesman Pericles in 429 b.c. and peer review form the strife of the Peloponnesian War, which lasted from 431 to 404 b.c. The era also exhibited remarkable cultural vitality and included the great dramatists Sophocles, Euripides, and organizational robbins Aristophanes, of whom Plato was a younger contemporary. Plato was descended from peer review form research paper, a distinguished family of statesmen; his mother's cousin Critias and his maternal uncle Charmides, both portrayed in eponymous dialogues, belonged to the Thirty Tyrants, the oligarchs who ruled Athens in cooperation with Sparta after the of sports essay, Peloponnesian War.

The unsettled political climate during the peer form paper, period gave rise to a class of itinerant professional instructors called Sophists who made their living teaching rhetoric and public speaking—skills prized in the political arena—as well as geometry, astronomy, and arithmetical calculation. Before In India! Socrates—whom the peer review form research, young Plato met while the elder Athenian discoursed in the streets and homes of the city on topics related to the virtuous life—objected to the aims of the Sophists, asserting that they manipulated language for their own ends, obfuscating and confusing in order to succeed in argumentation, rather than elucidating and searching for truth. Known primarily through Plato's dialogues, Socrates advocated a quest for self-knowledge and cultivation of the soul, and claimed that contemplation is the noblest human activity. Plato's own career as a writer spanned the greater part of his life. All of his known works, including thirty-four dialogues of varying length and paper thirteen epistles, are extant. Of these, the Republic is considered his greatest work because of the research, representative nature of its content as well as because of its importance as the premier example of ancient Greek prose.

Plot and Major Characters. Composed as a dramatic dialogue among various characters, the principal among them Socrates, the Republic is divided into on always teachers, ten main books. This division, as scholars have repeatedly pointed out, is somewhat artificial and was dictated more by the limitations of book production in ancient times—in this case, the amount of material that would fit onto a papyrus roll—rather than any internal break in the sequence of the argument. The text begins with a prelude, where the main characters and setting are introduced and the subject of the dialogue—justice, or right conduct—explained briefly. In addition to Socrates, who is the main narrator of the dialogue, other characters include Glaucon and Adeimantus, elder brothers of Plato, and Polemarchus, a resident of Athens at whose house the conversation takes place. Form Research Paper! Also present are Thrasymachus, a Sophist and orator as well as the main respondent in Book I; Lysias and Euthydemus, Polemarchus's brothers; and Niceratus, Charmantides, and Cleitophon. Ostensibly a discussion about the nature of importance essay justice, expounded on first by Thrasymachus, who states the Sophist position that justice and its related conventions are rules that were imposed on society by those in power, the rest of the form research paper, dialogue is mainly a response from Socrates to this statement. In essence, the argument to prove the inherent good of justice leads Plato, via Socrates, to lay out his vision of the ideal state, covering a wide range of topics, including the social, educational, psychological, moral, and philosophical aspects of the republic. The main intention of the Republic is to define the principles that govern an ideal society.

In doing so, Plato touches upon horse, many important ideas about education, ethics, politics, and peer research morality in this text. Scholars have pointed out that the respect your teachers, main argument of the Republic is partly a response to the political unrest and instability Plato witnessed in contemporary Athenian society. Following the end of the Peloponnesian War, Athens became a democracy of sorts, led mostly by laymen, who, in Plato's view, tended to implement policies based more on popular demand rather than necessity or principle. Thus, Plato developed a perspective that viewed all contemporary forms of form government as corrupt, theorizing that the only hope for finding true justice both for society and the individual lies in philosophy, and that “mankind will have no respite from trouble until either real philosophers gain political power, or politicians become by some miracle true philosophers.” This is the central theme of the Republic. In the context of this premise, Plato touches upon several major issues, focusing the essay respect your, most significant discussions on form paper, the nature and definition of ethics, education, and the organization of society and politics, as well as religion and philosophy. In contrast to the Sophists, who advocated the primacy of organizational robbins and job satisfaction rhetoric over moral training, Plato proposes the creation of an review form research, educational system that focuses on the molding of character, with the ultimate goal of the educator being not just imparting knowledge, but also the ability “to turn the mind's eye to the light so that it can see for itself.” According to Plato, one of the main problems of his society was the inability to robbins, distinguish true reality from reflections or images of reality. Peer Research Paper! Plato employs his famous allegory of the cave to illustrate how mankind learns and can be mislead by the manner in which he learns.

Plato's preferred educational system strictly controls the upbringing of the ruling class in organizational behavior satisfaction, order to help them differentiate between appearance and peer paper reality and form correct views. He advocates the study of mathematics and abstract ideas rather than art, music, or literature because the latter deal with representation of ideas, not ideas themselves; he even goes so far as to advocate censorship of in india art, when necessary, in the service of proper education. Another powerful focus in the Republic is the discussion of peer review form research justice. Responding primarily to the Sophists' position, that morality is important only because of the social and personal consequences that follow, Plato contends that morality and justice are key components of an importance essay, ideal society and that they must underlie all areas of human interaction. The Republic has a unique place in the history of Western literature because of its importance as a literary, political, as well as philosophical text. Its reception in early commentaries was particularly positive and for many centuries it was regarded as an peer, ideal text, based on its literary and thematic merits. A. E. Taylor's introduction to his translation of the essay respect your, Republic is an example of review form paper this critical approach.

Later commentators have been more critical, however, and many twentieth-century studies of the Republic have emphasized the totalitarian nature of Plato's society, critiquing him for the degree of power he invests in the philosopher rulers. In her introduction to before, the Republic Julia Annas remarks on the power of the text and the persuasiveness of Plato's assessments, noting that in some ways, the systematic treatment of such important subjects as morality, politics, and knowledge is “designed to sweep the reader along,” often leading first-time readers to either accept the peer paper, premise of the text without question or to farewell to arms research paper, reject it entirely. After further study, though, writes Annas, the Republic reveals itself as a work of research paper great complexity, and thus a text that rewards detailed analysis. In his assessment of the role of the good as it is explained by Plato, Mitchell Miller also comments on the multilayered nature of ideas presented in the Republic and focuses his discussion by farewell research paper, providing context from other contemporary sources of Greek prose. Other modern studies of Plato have also tended to focus on specific ideas explored in the Republic. For example, R. E. Allen (see Further Reading) explores the review form, speech of Glaucon to highlight the idea of justice and morality, while James O'Rourke ruminates about the respective positions accorded to myth and logic in Plato's ideal society. Before Independence! In his essay on slavery as it is defined in the Republic, Brian Calvert reviews other critical commentaries on this issue, concluding that Plato's republic “could not contain slaves.” Critical commentaries on peer review form research, the Republic continue to flourish, attesting to the sustaining power of the ideas contained in the text, whether they relate to importance of sports, society, politics, religion, education, or human nature. Access our Plato's Republic Study Guide for peer paper Free.

Apology (dialogue) before 387 b.c. Charmides (dialogue) before 387 b.c. Crito (dialogue) before 387 b.c. Euthyphro (dialogue) before 387 b.c. Gorgias (dialogue) before 387 b.c. Hippias Major (dialogue) before 387 b.c.

Hippias Minor (dialogue) before 387 b.c. Ion (dialogue) before 387 b.c. Laches (dialogue) before 387 b.c. Lysis (dialogue) before 387 b.c. Protagoras (dialogue) before 387 b.c.

Republic, Book I (dialogue) before 387 b.c. (The entire section is 257 words.) Get Free Access to this Plato#039;s Republic Study Guide. Start your 48-hour free trial to unlock this resource and thousands more. Get Better Grades.

Our 30,000+ summaries will help you comprehend your required reading to ace every test, quiz, and essay. We've broken down the chapters, themes, and characters so you can understand them on your first read-through. Access Everything From Anywhere. We have everything you need in one place, even if you're on the go. Download our handy iOS app for farewell research paper free. SOURCE: Taylor, A. E. “The Republic. ” In Plato: The Man and His Work, pp. 263-98. Form Research! London, Eng.: Methuen, 1948. [ In the following essay, first published in 1926 and revised in 1937, Taylor provides a detailed analysis of the ideas, language, and philosophy of farewell paper Plato's Republic.] The Republic is at once too long a work, and too well known by numerous excellent summaries and commentaries, to peer form research, require or permit analysis on the scale we have found necessary in dealing with the Phaedo or Protagoras.

We must be content to presume the student's acquaintance with its contents, and to offer some general considerations of the relation of paper its main. (The entire section is 19658 words.) Get Free Access to this Plato#039;s Republic Study Guide. Start your 48-hour free trial to unlock this resource and thousands more. SOURCE: Lerner, Ralph. Introduction to Averroes on Plato's Republic, translated by Ralph Lerner, pp. xiii-xxviii. Ithaca, N.Y.: Cornell University Press, 1974. [ In the following introduction to peer review form research, the medieval Arabic philosopher Averroes's commentary on Plato's Republic, Lerner discusses Averroes's approach to the text, noting that despite the differences in their religious backgrounds, Averroes exhibits a deep appreciation for Plato's philosophy. ] Why a Muslim like Averroes should choose to write on Plato's Republic is not immediately self-evident. Of what use is this pagan closet philosophy to men who already hold what they believe to be the inestimable. (The entire section is independence in india essay, 6273 words.)

SOURCE: Annas, Julia. Introduction to An Introduction to review form research, Plato's Republic, pp. 1-15. Oxford, Eng.: Clarendon Press, 1981. [ In the following essay, Annas presents an overview of the Republic in the context of politics and philosophy during Plato's time, also focusing on independence essay, Socrates' influence on peer form paper, Plato. ] The Republic is Plato's best-known work, and there are ways in independence, which it is form, too famous for horse its own good. It gives us systematic answers to a whole range of questions about morality, politics, knowledge, and metaphysics, and the book is written in a way designed to sweep the review, reader along and give a general grasp of the way Plato sees all these questions as. (The entire section is 7141 words.) SOURCE: Miller, Mitchell. “Platonic Provocations: Reflections on essay, the Soul and the Good in the Republic. ” In Platonic Investigations, edited by Dominic J. O'Meara, pp. 163-93.

Washington, D.C.: Catholic University of America Press, 1985. [ In the following essay, Miller explicates the fundamental philosophical positions adopted by Plato in the Republic.] If we do not understand [the Good], then even the greatest possible knowledge of other things is of no benefit to us. The aim of this reflection is to explore the nexus of review notoriously obscure notions that lies at the center of. (The entire section is 16239 words.) SOURCE: Calvert, Brian. “Slavery in in india, Plato's Republic. ” Classical Quarterly ns. 37, no. 2 (1987): 367-72. [ In the following essay, Calvert summarizes the critical debate over whether Plato's ideal republic would include slaves or not, concluding that although the peer form research, standard critical view supports the independence, existence of slavery in the republic, there is an equally balanced argument opposing the existence of the review form, practice. ] For a number of cirrhosis of the research years, in the not too distant past, there was a lively debate between Plato's defenders and critics over the question of whether his Republic contained slaves. However, since the appearance of an article by. (The entire section is 3780 words.)

James O#039;Rourke (essay date summer 1987) SOURCE: O'Rourke, James. “Mythos and Logos in the Republic. ” Clio 16, no. 4 (summer 1987): 381-96. [ Characterizing the Republic as a “foundational text in Western thought,” O'Rourke contends that the emphasis accorded to peer paper, logic over behavior robbins and job myth in this work imbues it with an inherent structural instability. ] The Republic is perhaps the foundational text in Western thought that gives dominion to logos over review research paper mythos. This paper is about the instability of that hierarchy in the text of the Republic, and the consequences of that instability. The justifications Socrates gives in essay, the latter part of the Republic for why the. (The entire section is 7342 words.) Anthony Skillen (essay date July 1992) SOURCE: Skillen, Anthony. “Fiction Year Zero: Plato's Republic. Review Research! ” The British Journal of Aesthetics 32, no.

3 (July 1992): 201-08. [ In the following essay, Skillen presents an essay, account of Plato's views on fiction as they are laid out in the Republic.] Then it will be our first business to supervise the production of review form paper stories, and choose only those we think suitable, and reject the rest … the worst fault possible, especially if the fiction is an ugly one, is misrepresenting the nature of gods and heroes, like a portrait painter whose portraits bear no resemblance to their originals … (The entire section is cirrhosis of the research, 3793 words.) SOURCE: Aune, Bruce. “The Unity of Plato's Republic. ” Ancient Philosophy 17, no. 2 (fall 1997): 291-308. [ In the following essay, Aune investigates charges of review form paper structural disunity between the two books of the Republic, maintaining that a close examination of the two parts reveals a style and method of inquiry in horse plan, part II that are very similar to those of part I. ] How well does Republic i fit together with the review form research, books that follow? Does it contribute to, or detract from, the unity of the dialogue as a philosophical work?

There is still disagreement about this matter. 1 Irwin 1995, 169 speaks of book 1 as the first of horse business two ‘long. (The entire section is 10235 words.) Elizabeth F. Cooke (essay date spring 1999) SOURCE: Cooke, Elizabeth F. “The Moral and Intellectual Development of the Philosopher in Plato's Republic. ” Ancient Philosophy 19, no. 1 (spring 1999): 37-44. [ In the following essay, Cooke comments on Plato's view of the role of philosophy in everyday life, stating that for Plato, philosophy is peer review form research, not an abstract concept, but one that draws from all aspects of life, including the spiritual, moral, and intellectual. ] The metaphysical knowledge required for in india essay the philosopher is peer paper, often seen as merely abstract and theoretical, though the philosophers share in behavior robbins, the same early character education as that of the spirited auxiliaries. This is not a mere oversight by. (The entire section is 3589 words.)

Donald Morrison (essay date spring 2001) SOURCE: Morrison, Donald. “The Happiness of the research paper, City and the Happiness of the organizational behavior attitudes satisfaction, Individual in Plato's Republic. ” Ancient Philosophy 21, no. 1 (spring 2001): 1-24. [ In the following essay, Morrison reflects on the relationship between the happiness of peer form individuals and the happiness of the city as it is outlined in the Republic.] Is the polis, as conceived by Plato in the Republic, some kind of ‘super-individual’, or is it nothing over and above its component individuals? Is the happiness of the polis a separate and farewell research paper transcendent value, for which the happiness of its citizens might be sacrificed, or not? Answers to peer, these questions are often grouped into. (The entire section is essay on always your, 12492 words.) David N. McNeill (essay date December 2001) SOURCE: McNeill, David N. “Human Discourse, Eros, and Madness in review research paper, Plato's Republic. ” Review of Metaphysics 55, (December 2001): 235-68. [ In the following essay, McNeill compares three variations on the idea of eros as presented in Plato's Republic, Phaedrus and Symposium.]

In book 9 of the Republic, Socrates tells Adeimantus that the “tyrant-makers” manage to defeat the relatives of the nascent tyrant in the battle over the young man's soul by contriving “to make in him some eros, a sort of great winged drone, to be the leader of the idle desires.” This “leader of the soul,” Socrates claims, (The entire section is 13291 words.) Allen, R. E. “The Speech of Glaucon in research paper, Plato's Republic. ” Journal of the History of Philosophy 25, no. 1 (January 1987): 3-11. Outline of Plato's position on peer, the “good” as it is explicated via the dialogue between Glaucon and Socrates in the second book of the Republic. Kahn, Charles H. Independence In India! “Plato's Theory of peer review Desire.” The Review of Metaphysics 41, no.1, issue no. 161 (September 1987): 77-103. Investigates Plato's theory of the psyche and desire as it is expressed in the Republic, noting that Plato is the essay on always respect, first western philosopher to peer review form research, deal with these topics in a systematic manner. . (The entire section is 379 words.)

Plato's Republic Homework Help Questions. The main theme of Plato’s allegory of the cave is that we humans tend not to understand the true reality of our world. We think that we understand what we are looking at and sensing in our. Plato favored an aristocracy ruled by philosopher kings. He did not believe most societies could maintain it though. Plato’s aristocracy was based on farewell research paper, merit. The leaders were strong. Plato's ideal society is built on the ideal of review paper justice. Just as he believed the soul was composed of three hierarchical parts—appetitive, rational, and spiritual—he believed a just society. Well, hate may be too strong of a word, but he certainly wasn't a fan. The reason is because Plato was convinced that not all people had the intellectual ability to rule.

It is an organizational robbins attitudes satisfaction, elitist. The Ring of Gyges was an oral legend told to review form paper, Plato by on always respect, his brother Glaucon, and review research paper recounted in The Republic. The story concerned a magic ring that made its wearer invisible; this allowed the.

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UML, le langage de modlisation objet unifi. N de la fusion des mthodes objet dominantes (OMT, Booch et OOSE), puis normalis par l'OMG en 1997, UML est rapidement devenu un standard incontournable. Peer Review Form? UML n'est pas l'origine des concepts objet, mais il en en donne une dfinition plus formelle et apporte la dimension mthodologique qui faisait dfaut l'approche objet. Le but de cette prsentation n'est pas de faire l'apologie d'UML, ni de restreindre UML sa notation graphique, car le vritable intrt d'UML est ailleurs ! En effet, matriser la notation graphique d'UML n'est pas une fin en soi. Importance? Ce qui est primordial, c'est d'utiliser les concepts objet bon escient et d'appliquer la dmarche d'analyse correspondante.

Cette prsentation a donc pour objectif, d'une part, de montrer en quoi l'approche objet et UML constituent un plus et d'autre part, d'exposer comment utiliser UML dans la pratique, c'est--dire comment intgrer UML dans un processus de dveloppement et comment modliser avec UML. Les textes qui composent la prsentation sont (volontairement) trs synthtiques, la manire de transparents qu'on projette au cours d'une formation. Il faut donc savoir lire entre les lignes, car il ne s'agit l que d'un tour d'horizon. Peer Form Research Paper? Cette prsentation ne se substitue donc ni aux formations plus acadmiques, ni aux ouvrages de rfrence. Article lu fois. Publié le 22 octobre 2007 - Mis à jour le 14 septembre 2009. I-A-1. Essay? Approche fonctionnelle vs. Form Paper? approche objet^ I-A-1-a.

La dcoupe fonctionnelle d'un problme informatique : une approche intuitive^ Exemple de dcoupe fonctionnelle d'un logiciel ddi la gestion d'une bibliothque : Le logiciel est compos d'une hirarchie de fonctions, qui ensemble, fournissent les services dsirs, ainsi que de donnes qui reprsentent les lments manipuls (livres, etc…). Horse Business? Logique, cohrent et intuitif. I-A-1-b. Review Form Paper? Le plus de l'approche fonctionnelle : la factorisation des comportements^ Une dcoupe fonctionnelle intelligente consiste factoriser certains comportements communs du logiciel. In India? En d'autres termes : pour raliser une fonction du logiciel, on peer form, peut utiliser un ensemble d'autres fonctions, dj disponibles, pour peu qu'on rende ces dernires un tant soit peu gnriques. Cirrhosis Research? Gnial ! I-A-1-c.

Le revers de la mdaille : maintenance complexe en cas d'volution^ Factoriser les comportements n'a malheureusement pas que des avantages. Peer Review? Les fonctions sont devenues interdpendantes : une simple mise jour du logiciel un point donn, peut impacter en cascade une multitude d'autres fonctions. Of Sports Essay? On peut minorer cet impact, pour peu qu'on utilise des fonctions plus gnriques et des structures de donnes ouvertes. Review Form Paper? Mais respecter ces contraintes rend l'criture du logiciel et sa maintenance plus complexe. En cas d'volution majeure du logiciel (passage de la gestion d'une bibliothque celle d'une mdiathque par exemple), le scnario est encore pire. Behavior And Job? Mme si la structure gnrale du logiciel reste valide, la multiplication des points de maintenance, engendre par le chanage des fonctions, rend l'adaptation trs laborieuse. Peer Form Research? Le logiciel doit tre retouch dans sa globalit : I-A-1-d. Importance Of Sports Essay? La sparation des donnes et des traitements : le pige !^ Examinons le problme de l'volution de code fonctionnel plus en dtail.

Faire voluer une application de gestion de bibliothque pour grer une mdiathque, afin de prendre en compte de nouveaux types d'ouvrages (cassettes vido, CD-ROM, etc. Review? ), ncessite : de faire voluer les structures de donnes qui sont manipules par les fonctions, d'adapter les traitements, qui ne manipulaient l'origine qu'un seul type de document (des livres). Il faudra donc modifier toutes les portions de code qui utilisent la base documentaire, pour grer les donnes et les actions propres aux diffrents types de documents. Il faudra par exemple modifier la fonction qui ralise l'dition des lettres de rappel (une lettre de rappel est une mise en demeure, qu'on envoie automatiquement aux personnes qui tardent rendre un ouvrage emprunt). In India Essay? Si l'on dsire que le dlai avant rappel varie selon le type de document emprunt, il faut prvoir une rgle de calcul pour chaque type de document. En fait, c'est la quasi-totalit de l'application qui devra tre adapte, pour grer les nouvelles donnes et raliser les traitements correspondants. Peer Review Research? Et cela, chaque fois qu'on dcidera de grer un nouveau type de document ! I-A-1-e.

1re amlioration : rassembler les valeurs qui caractrisent un type, dans le type^ Une solution relativement lgante la multiplication des branches conditionnelles et des redondances dans le code (consquence logique d'une trop grande ouverture des donnes), consiste tout simplement centraliser dans les structures de donnes, les valeurs qui leurs sont propres : Quoi de plus logique ? En effet, le dlai avant dition d'une lettre de rappel est bien une caractristique propre tous les ouvrages grs par notre application. Mais cette solution n'est pas encore optimale ! I-A-1-f. Research Paper? 2me amlioration : centraliser les traitements associs un type, auprs du type^ Pourquoi ne pas aussi rassembler dans une mme unit physique les types de donnes et tous les traitements associs ? Que se passerait-il par exemple si l'on centralisait dans un mme fichier, la structure de donnes qui dcrit les documents et la fonction de calcul du dlai avant rappel ? Cela nous permettrait de retrouver en un clin d'oeil le bout de code qui est charg de calculer le dlai avant rappel d'un document, puisqu'il se trouve au plus prs de la structure de donnes concerne.

Ainsi, si notre mdiathque devait grer un nouveau type d'ouvrage, il suffirait de modifier une seule fonction (qu'on sait retrouver instannment), pour assurer la prise en compte de ce nouveau type de document dans le calcul du dlai avant rappel. Paper? Plus besoin de fouiller partout dans le code. Ecrit en ces termes, notre logiciel sera plus facile maintenir et bien plus lisible. Essay Your? Le stockage et le calcul du dlai avant rappel des documents, est dsormais assur par une seule et unique unit physique (quelques lignes de code, rapidement identifiables). Pour accder la caractristique dlai avant rappel d'un document, il suffit de rcuprer la valeur correspondante parmi les champs qui dcrivent le document.

Pour assurer la prise en compte d'un nouveau type de document dans le calcul du dlai avant rappel, il suffit de modifier une seule fonction, situe au mme endroit que la structure de donnes qui dcrit les documents : En rsum : centraliser les donnes d'un type et les traitements associs, dans une mme unit physique, permet de limiter les points de maintenance dans le code et facilite l'accs l'information en cas d'volution du logiciel : Les modifications que nous avons apport notre logiciel de gestion de mdiathque, nous ont amen transformer ce qui tait l'origine une structure de donnes, manipule par des fonctions, en une entit autonome, qui regroupe un ensemble de proprits cohrentes et de traitements associs. Paper? Une telle entit s'appelle. Before Independence Essay? un objet et constitue le concept fondateur de l'approche du mme nom ! Un objet est une entit aux frontires prcises qui possde une identit (un nom). Form Research Paper? Un ensemble d'attributs caractrise l'tat de l'objet. In India? Un ensemble d'oprations (mthodes) en dfinissent le comportement. Form Research? Un objet est une instance de classe (une occurrence d'un type abstrait). Essay? Une classe est un type de donnes abstrait, caractris par des proprits (attributs et mthodes) communes des objets et permettant de crer des objets possdant ces proprits.

I-A-2. Review? Quels sont les autres concepts importants de l'approche objet ?^ Consiste masquer les dtails d'implmentation d'un objet, en dfinissant une interface. Behavior Robbins? L'interface est la vue externe d'un objet, elle dfinit les services accessibles (offerts) aux utilisateurs de l'objet. Review Form Research Paper? L'encapsulation facilite l'volution d'une application car elle stabilise l'utilisation des objets : on paper, peut modifier l'implmentation des attributs d'un objet sans modifier son interface. Peer Review Form Paper? L'encapsulation garantit l'intgrit des donnes, car elle permet d'interdire l'accs direct aux attributs des objets (utilisation d'accesseurs). L'hritage est un mcanisme de transmission des proprits d'une classe (ses attributs et mthodes) vers une sous-classe. Business? Une classe peut tre spcialise en d'autres classes, afin d'y ajouter des caractristiques spcifiques ou d'en adapter certaines. Review? Plusieurs classes peuvent tre gnralises en une classe qui les factorise, afin de regrouper les caractristiques communes d'un ensemble de classes. Business? La spcialisation et la gnralisation permettent de construire des hirarchies de classes. Form Research Paper? L'hritage peut tre simple ou multiple.

L'hritage vite la duplication et encourage la rutilisation. Respect? Le polymorphisme reprsente la facult d'une mthode pouvoir s'appliquer des objets de classes diffrentes. Peer Research? Le polymorphisme augmente la gnricit du code. Exemple d'une hirarchie de classes : Il s'agit d'une relation entre deux classes, spcifiant que les objets d'une classe sont des composants de l'autre classe. Une relation d'agrgation permet donc de dfinir des objets composs d'autres objets. Before In India Essay? L'agrgation permet d'assembler des objets de base, afin de construire des objets plus complexes.

I-A-2-d. Peer Review Form Research? Rsum sur les concepts fondateurs de l'approche objet^ la notion d'objet et de classe (d'objets) l'encapsulation (les interfaces des objets) l'hritage (les hirarchies d'objets) l'agrgation (la construction d'objets l'aide d'objets) Remarque : Les langages orients objet fournissent de nombreux autres mcanismes qui affinent ces concepts de base, favorisent la gnricit du code ou amliorent sa robustesse. I-A-2-e.

L'approche objet, hier et aujourd'hui^ Les concepts objet sont stables et prouvs (issus du terrain) Simula, 1er langage de programmation implmenter le concept de type abstrait ( l'aide de classes), date de 1967 ! En 1976 dj, Smalltalk implmente les concepts fondateurs de l'approche objet (encapsulation, agrgation, hritage) l'aide de : classes associations entre classes hirarchies de classes messages entre objets Le 1er compilateur C++ date de 1980, et C++ est normalis par l'ANSI. To Arms Paper? De nombreux langages orients objets acadmiques ont tays les concepts objets : Eiffel, Objective C, Loops. Peer Form? Les concepts objet sont anciens, mais ils n'ont jamais t autant d'actualit L'approche fonctionnelle n'est pas adapte au dveloppement d'applications qui voluent sans cesse et dont la complexit croit continuellement. Before In India? L'approche objet a t invente pour faciliter l'volution d'applications complexes.

De nos jours, les outils orients objet sont fiables et performants Les compilateurs C++ produisent un code robuste et optimis. Research? De trs nombreux outils facilitent le dveloppement d'applications C++ : gnrateurs d'IHM (Ilog Views, TeleUse. Farewell To Arms Research? ) bibliothques (STL, USL, Rogue Wave, MFC. Peer Review Form Paper? ) environnements de dveloppement intgrs (Developper Studio, Sniff+. Business? ) outils de qualimtrie et de tests (Cantata++, Insure++, Logiscope. Peer Review Form Research Paper? ) bases de donnes orientes objet (O2, ObjectStore, Versant. Before In India? ) I-A-2-f. Paper? L'approche objet : une solution parfaite ?^ Un ensemble de concepts stables, prouvs et normaliss. Teachers? Une solution destine faciliter l'volution d'applications complexes. Peer Research? Une panoplie d'outils et de langages performants pour le dveloppement. Malgr les apparences, il est plus naturel pour nos esprits cartsiens, de dcomposer un problme informatique sous forme d'une hirarchie de fonctions atomiques et de donnes, qu'en terme d'objets et d'interaction entre ces objets. Liver Research? De plus, le vocabulaire prcis est un facteur d'chec important dans la mise en oeuvre d'une approche objet.

L'approche objet est moins intuitive que l'approche fonctionnelle ! Quels moyens utiliser pour faciliter l'analyse objet ? Quels critres identifient une conception objet pertinente ? Comment comparer deux solutions de dcoupe objet d'un systme ? L'application des concepts objets ncessite une grande rigueur ! Le vocabulaire est prcis (risques d'ambiguts, d'incomprhensions). Peer Form Research? Comment dcrire la structure objet d'un systme de manire pertinente ? I-A-2-g. Organizational? Quels sont les remdes aux inconvnients de l'approche objet ?^ Un langage pour exprimer les concepts objet qu'on utilise, afin de pouvoir : Reprsenter des concepts abstraits (graphiquement par exemple). Peer? Limiter les ambiguts (parler un langage commun). In India Essay? Faciliter l'analyse (simplifier la comparaison et l'valuation de solutions). Form Research? Une dmarche d'analyse et de conception objet, pour : Ne pas effectuer une analyse fonctionnelle et se contenter d'une implmentation objet, mais penser objet ds le dpart. Cirrhosis Of The Liver Paper? Dfinir les vues qui permettent de couvrir tous les aspects d'un systme, avec des concepts objets. Bref : il nous faut un outil qui apporte une dimension mthodologique l'approche objet, afin de mieux matriser sa richesse et sa complexit.

I-B. Form Research Paper? Les mthodes objet et la gense d'UML^ Les premires mthodes d'analyse (annes 70) Dcoupe cartsienne (fonctionnelle et hirarchique) d'un systme. Of Sports Essay? L'approche systmique (annes 80) Modlisation des donnes + modlisation des traitements (Merise, Axial, IE. Peer Review? ). Essay On Always Respect Your? L'mergence des mthodes objet (1990-1995) Prise de conscience de l'importance d'une mthode spcifiquement objet : comment structurer un systme sans centrer l'analyse uniquement sur les donnes ou uniquement sur les traitements (mais sur les deux) ? Plus de 50 mthodes objet sont apparues durant cette priode (Booch, Classe-Relation, Fusion, HOOD, OMT, OOA, OOD, OOM, OOSE. Peer Review Form? ) ! Aucun mthode ne s'est rellement impose. Paper? Les premiers consensus (1995) OMT (James Rumbaugh) : vues statiques, dynamiques et fonctionnelles d'un systme Issue du centre de RD de General Electric. Review? Notation graphique riche et lisible. Before? OOD (Grady Booch) : vues logiques et physiques du systme Dfinie pour le DOD, afin de rationaliser de dveloppement d'applications ADA, puis C++. Review Form Research Paper? Ne couvre pas la phase d'analyse dans ses 1res versions (prconise SADT).

Introduit le concept de package (lment d'organisation des modles) OOSE (Ivar Jacobson) : couvre tout le cycle de dveloppement Issue d'un centre de dveloppement d'Ericsson, en Sude. Essay On Always Teachers? La mthodologie repose sur l'analyse des besoins des utilisateurs. Peer Review? L'unification et la normalisation des mthodes (1995-1997) UML (Unified Modeling Langage), la fusion et synthse des mthodes dominantes : UML aujourd'hui : un standard incontournable UML est le rsultat d'un large consensus (industriels, mthodologistes. Cirrhosis Of The Liver? ). Review Form Research Paper? UML est le fruit d'un travail d'experts reconnus. Research Paper? UML est issu du terrain. Form Research Paper? UML est riche (il couvre toutes les phases d'un cycle de dveloppement). Business Plan? UML est ouvert (il est indpendant du domaine d'application et des langages d'implmentation). Form Paper? Aprs l'unification et la standardisation, bientt l'industrialisation d'UML : les outils qui supportent UML se multiplient (GDPro, ObjectTeam, Objecteering, OpenTool, Rational Rose, Rhapsody, STP, Visio, Visual Modeler, WithClass. Essay On Always Respect Your? ). Peer Review Form Research Paper? XMI (format d'change standard de modles UML). Research Paper? UML volue mais reste stable ! L'OMG RTF (nombreux acteurs industriels) centralise et normalise les volutions d'UML au niveau international. Paper? Les groupes d'utilisateurs UML favorisent le partage des expriences. Research Paper? De version en version, UML gagne en maturit et prcision, tout en restant stable.

UML inclut des mcanismes standards d'auto-extension. Peer Form? La description du mtamodle d'UML est standardise (OMG-MOF). UML n'est pas une mode, c'est un investissement fiable ! Si l'on parle de mthode objet pour UML, c'est par abus de langage ! Ce constat vaut aussi pour OMT ou d'autres techniques / langages de modlisation. Independence? Une mthode propose aussi un processus, qui rgit notamment l'enchanement des activits de production d'une entreprise. Form Research Paper? UML a t pens pour permettre de modliser les activits de l'entreprise, pas pour les rgir (ce n'est pas CMM ou SPICE).

Un processus de dveloppement logiciel universel est une utopie : Impossible de prendre en compte toutes les organisations et cultures d'entreprises. Before Independence? Un processus est adapt (donc trs li) au domaine d'activit de l'entreprise. Peer Form? Mme si un processus constitue un cadre gnral, il faut l'adapter de manire prcise au contexte de l'entreprise. UML est fond sur un mtamodle, qui dfinit : les lments de modlisation (les concepts manipuls par le langage), la smantique de ces lments (leur dfinition et le sens de leur utilisation). Essay? Un mtamodle est une description trs formelle de tous les concepts d'un langage. Peer Review Form Research Paper? Il limite les ambiguts et encourage la construction d'outils.

Le mtamodle d'UML permet de classer les concepts du langage (selon leur niveau d'abstraction ou domaine d'application) et expose sa structure. Essay On Always Your Teachers? Le mtamodle UML est lui-mme dcrit par un mta-mtamodle (OMG-MOF). Peer Research? UML propose aussi une notation, qui permet de reprsenter graphiquement les lments de modlisation du mtamodle. Paper? Cette notation graphique est le support du langage UML. diffrentes vues (perspectives) complmentaires d'un systme, qui guident l'utilisation des concept objets, plusieurs niveaux d'abstraction, qui permettent de mieux contrler la complexit dans l'expression des solutions objets. Sa notation graphique permet d'exprimer visuellement une solution objet.

L'aspect formel de sa notation limite les ambiguts et les incomprhensions. Peer Review Paper? Son aspect visuel facilite la comparaison et l'valuation de solutions. Business Plan? Son indpendance (par rapport aux langages d'implmentation, domaine d'application, processus. Peer Form Paper? ) en font un langage universel. I-C. Essay? Avantages et inconvnients d'UML^ gain de prcision gage de stabilit encourage l'utilisation d'outils. Il cadre l'analyse. Peer Review Form? Il facilite la comprhension de reprsentations abstraites complexes.

Son caractre polyvalent et sa souplesse en font un langage universel. La mise en pratique d'UML ncessite un apprentissage et passe par une priode d'adaptation. Mme si l'Espranto est une utopie, la ncessit de s'accorder sur des modes d'expression communs est vitale en informatique. Before In India Essay? UML n 'est pas l'origine des concepts objets, mais en constitue une tape majeure, car il unifie les diffrentes approches et en donne une dfinition plus formelle. Or, l'intgration d'UML dans un processus n'est pas triviale et amliorer un processus est un tche complexe et longue. Les auteurs d'UML sont tout fait conscients de l'importance du processus, mais l'acceptabilit industrielle de la modlisation objet passe d'abord par la disponibilit d'un langage d'analyse objet performant et standard.

Un modle est une abstraction de la ralit. L'abstraction est un des piliers de l'approche objet. Il s'agit d'un processus qui consiste identifier les caractristiques intressantes d'une entit, en vue d'une utilisation prcise. Peer Review Paper? L'abstraction dsigne aussi le rsultat de ce processus, c'est--dire l'ensemble des caractristiques essentielles d'une entit, retenues par un observateur. Horse Business? Un modle est une vue subjective mais pertinente de la ralit Un modle dfinit une frontire entre la ralit et la perspective de l'observateur. Peer Form Research Paper? Ce n'est pas la ralit, mais une vue trs subjective de la ralit. Horse Plan? Bien qu'un modle ne reprsente pas une ralit absolue, un modle reflte des aspects importants de la ralit, il en donne donc une vue juste et pertinente. Peer Form? Quelques exemples de modles Modle mtorologique : partir de donnes d'observation (satellite . Of Sports? ), permet de prvoir les conditions climatiques pour les jours venir. Peer? Modle conomique : peut par exemple permettre de simuler l'volution de cours boursiers en fonction d'hypothses macro-conomiques (volution du chmage, taux de croissance. Before Independence? ). Review Form? Modle dmographique : dfinit la composition d'un panel d'une population et son comportement, dans le but de fiabiliser des tudes statistiques, d'augmenter l'impact de dmarches commerciales, etc. Independence Essay? Caractristiques fondamentales des modles. Le caractre abstrait d'un modle doit notamment permettre : de faciliter la comprhension du systme tudi.

Un modle rduit la complexit du systme tudi. Peer Review Form Research Paper? de simuler le systme tudi. Un modle reprsente le systme tudi et reproduit ses comportements. Un modle rduit (dcompose) la ralit, dans le but de disposer d'lments de travail exploitables par des moyens mathmatiques ou informatiques : UML est un langage qui permet de reprsenter des modles, mais il ne dfinit pas le processus d'laboration des modles ! Cependant, dans le cadre de la modlisation d'une application informatique, les auteurs d'UML prconisent d'utiliser une dmarche : itrative et incrmentale, guide par les besoins des utilisateurs du systme, centre sur l'architecture logicielle. D'aprs les auteurs d'UML, un processus de dveloppement qui possde ces qualits devrait favoriser la russite d'un projet. II-B-1. Horse? Une dmarche itrative et incrmentale ?^ L'ide est simple : pour modliser (comprendre et reprsenter) un systme complexe, il vaut mieux s'y prendre en plusieurs fois, en affinant son analyse par tapes. Peer Review Form Paper? Cette dmarche devrait aussi s'appliquer au cycle de dveloppement dans son ensemble, en favorisant le prototypage.

Le but est de mieux matriser la part d'inconnu et d'incertitudes qui caractrisent les systmes complexes. II-B-2. Essay? Une dmarche pilote par les besoins des utilisateurs ?^ Le primtre du systme modliser est dfini par les besoins des utilisateurs (les utilisateurs dfinissent ce que doit tre le systme). Review Research Paper? Le but du systme modliser est de rpondre aux besoins de ses utilisateurs (les utilisateurs sont les clients du systme).

A chaque itration de la phase d'analyse, on importance, clarifie, affine et valide les besoins des utilisateurs. Research Paper? A chaque itration de la phase de conception et de ralisation, on essay, veille la prise en compte des besoins des utilisateurs. Peer Paper? A chaque itration de la phase de test, on behavior, vrifie que les besoins des utilisateurs sont satisfaits. II-B-3. Review Form Paper? Une dmarche centre sur l'architecture ?^ Une architecture adapte est la cl de vote du succs d'un dveloppement. Elle dcrit des choix stratgiques qui dterminent en grande partie les qualits du logiciel (adaptabilit, performances, fiabilit. Horse Plan? ). Cette vue (4+1) a fortement inspir UML : II-B-4. Peer Review? Dfinir une architecture avec UML (dtail de la vue 4+1)^ Cette vue de haut niveau se concentre sur l'abstraction et l'encapsulation, elle modlise les lments et mcanismes principaux du systme.

Elle identifie les lments du domaine, ainsi que les relations et interactions entre ces lments : les lments du domaine sont lis au(x) mtier(s) de l'entreprise, ils sont indispensables la mission du systme, ils gagnent tre rutiliss (ils reprsentent un savoir-faire). Horse Business Plan? Cette vue organise aussi (selon des critres purement logiques), les lments du domaine en catgories : pour rpartir les tches dans les quipes, regrouper ce qui peut tre gnrique, isoler ce qui est propre une version donne, etc. Cette vue de bas niveau (aussi appele vue de ralisation), montre : L'allocation des lments de modlisation dans des modules (fichiers sources, bibliothques dynamiques, bases de donnes, excutables, etc. Review Paper? ). Plan? En d'autres termes, cette vue identifie les modules qui ralisent (physiquement) les classes de la vue logique. Paper? L'organisation des composants, c'est--dire la distribution du code en gestion de configuration, les dpendances entre les composants. Business? Les contraintes de dveloppement (bibliothques externes. Research? ). Respect Your? La vue des composants montre aussi l'organisation des modules en sous-systmes, les interfaces des sous-systmes et leurs dpendances (avec d'autres sous-systmes ou modules). Cette vue est trs importante dans les environnements multitches ; elle montre : La dcomposition du systme en terme de processus (tches). Peer Research? Les interactions entre les processus (leur communication). Of The Liver Research? La synchronisation et la communication des activits parallles (threads). Cette vue trs importante dans les environnements distribus, dcrit les ressources matrielles et la rpartition du logiciel dans ces ressources := La disposition et nature physique des matriels, ainsi que leurs performances. Form Research? L'implantation des modules principaux sur les noeuds du rseau.

Les exigences en terme de performances (temps de rponse, tolrance aux fautes et pannes. Respect? ). Cette vue (dont le nom exact est vue des cas d'utilisation), guide toutes les autres. Peer Research Paper? Dessiner le plan (l'architecture) d'un systme informatique n'est pas suffisant, il faut le justifier ! Cette vue dfinit les besoins des clients du systme et centre la dfinition de l'architecture du systme sur la satisfaction (la ralisation) de ces besoins. Organizational Behavior Robbins And Job Satisfaction? A l'aide de scnarios et de cas d'utilisation, cette vue conduit la dfinition d'un modle d'architecture pertinent et cohrent. Review Form? Cette vue est la colle qui unifie les quatre autres vues de l'architecture. Business? Elle motive les choix, permet d'identifier les interfaces critiques et force se concentrer sur les problmes importants. Modliser une application ? Mais comme UML n'est pas un processus. Quelle dmarche utiliser ? Optez pour une approche itrative et incrmentale.

Centrez votre dmarche sur l'analyse des besoins des utilisateurs. Review Form? Prenez grand soin la dfinition de l'architecture de votre application (l'approche 4+1 permet de mieux la cerner). Bien qu'UML n'est pas un processus, il facilite une dmarche d'analyse itrative et incrmentale, base sur les niveaux d'abstraction. Before Independence In India Essay? Les niveaux d'abstraction permettent de structurer les modles. Form Research? Un micro-processus rgit les itrations niveau d'abstraction constant. Essay On Always? Un macro-processus rgit le passage de niveau niveau. Peer Form Research Paper? Une dmarche incrmentale consiste construire les modles de spcification et de conception en plusieurs tapes (cible = catgories). Le schma ci-dessous montre les niveaux d'abstraction principaux, qu'on peut identifier dans un processus de dveloppement logiciel : II-B-6.

Elaboration plutt que transformation^ Les modles d'analyse et de conception ne diffrent que par leur niveau de dtail, il n'y a pas de diffrence dans les concepts utiliss. Horse Plan? UML n'introduit pas d'lments de modlisation propres une activit (analyse, conception. Research Paper? ) ; le langage reste le mme tous les niveaux d'abstraction. L'laboration encourage une approche non linaire (les retours en arrire entre niveaux d'abstraction diffrents sont facilits). Importance Essay? La traabilit entre modles de niveaux diffrents est assure par l'unicit du langage.

II-B-7. Review Form Research? Dtail des diffrents niveaux d'abstraction (phases du macro-processus)^ L'entre de l'analyse ce niveau, est le dossier d'expression des besoins client. Independence Essay? A ce niveau d'abstraction, on peer research paper, doit capturer les besoins principaux des utilisateurs. Cirrhosis Of The Liver Research? Il ne faut pas chercher l'exhaustivit, mais clarifier, filtrer et organiser les besoins ! Le but de la conceptualisation est : de dfinir le contour du systme modliser (de spcifier le quoi), de capturer les fonctionnalits principales du systme, afin d'en fournir une meilleure comprhension (le modle produit sert d'interface entre les acteurs du projet), de fournir une base la planification du projet. L'entre de l'analyse ce niveau, est le modle des besoins clients (les cas d'utilisation UML). Peer Paper? Il s'agit de modliser les lments et mcanismes principaux du systme.

On identifie les lments du domaine, ainsi que les relations et interactions entre ces lments : les lments du domaine sont lis au(x) mtier(s) de l'entreprise, ils sont indispensables la mission du systme, ils gagnent tre rutiliss (ils reprsentent un savoir-faire). Liver? A ce stade, on peer review research, organise aussi (selon des critres purement logiques), les lments du domaine en catgories : pour rpartir les tches dans les quipes, regrouper ce qui peut tre gnrique, etc. A ce niveau, on on always, modlise les aspects informatiques du systme, sans pour autant rentrer dans les dtails d'implmentation. Peer Review Paper? Les interfaces des lments de modlisation sont dfinis (cf. Farewell To Arms Paper? encapsulation). Peer Form Research Paper? Les relations entre les lments des modles sont dfinies. Cirrhosis Of The Research Paper? Les lments de modlisation utiliss peuvent tre propres une version du systme. On y modlise tous les rouages d'implmentation et on research, dtaille tous les lments de modlisation issus des niveaux suprieurs.

Les modles sont optimiss, car destins tre implments. II-B-8. Of Sports Essay? Activits des micro-processus d'analyse (niveau d'abstraction constant)^ A chaque niveau d'abstraction, un micro-processus rgit la construction des modles. Research? UML ne rgit pas les activits des micro-processus, c'est le principe d'abstraction qui permet l'laboration itrative et incrmentale des modles.

Exemple de micro-processus de construction d'un modle : recherchez les classes candidates (diffrentes suivant le niveau d'abstraction) l'aide de diagrammes d'objets (bauches), filtrez les classes redondantes, trop spcifiques ou vagues, qui ne reprsentent qu'une opration ou un attribut, documentez les caractristiques des classes retenues (persistances, nombre maximum d'instances, etc.). recherchez les connexions smantiques et les relations d'utilisation, documentez les relations (nom, cardinalits, contraintes, rles des classes. Plan? ), en spcification, filtrez les relations instables ou d'implmentation, dfinissez la dynamique des relations entre objets (les interactions entre instances de classes et les activits associes). recherchez les attributs dans les modles dynamiques (recherchez les donnes qui caractrisent les tats des objets), filtrez les attributs complexes (faites-en des objets) et au niveau spcification, ne reprsentez pas les valeurs internes propres aux mcanismes d'implmentation, recherchez les oprations parmi les activits et actions des objets (ne pas rentrer dans le dtail au niveau spcification). choisissez vos critres d'optimisation (gnricit, volutivit, prcision, lisibilit, simplicit. Paper? ), utilisez la gnralisation et la spcialisation (classification), documentez et dtaillez vos modles, encapsulez. vrifiez la cohrence, la compltude et l'homognit des modles, confrontez les modles la critique (comit de relecture. Farewell To Arms Research? ). Modliser une application n'est pas une activit linaire. itrative et incrmentale (grce aux niveaux d'abstraction), car il est plus efficace de construire et valider par tapes, ce qui est difficile cerner et matriser, centre sur l'architecture (dfinie par la vue 4+1), car il s'agit de la cl de vote qui conditionne la plupart des qualits d'une application informatique, guide par la prise en compte des besoins des utilisateurs ( l'aide des cas d'utilisation), car ce qui motive l'existence mme du systme concevoir, c'est la satisfaction des besoins de ses utilisateurs. OK pour la dmarche d'laboration d'un modle, mais. II-B-10-a. Peer? Comment rdiger un modle avec UML ?^ UML permet de dfinir et de visualiser un modle, l'aide de diagrammes.

Un diagramme UML est une reprsentation graphique, qui s'intresse un aspect prcis du modle ; c'est une perspective du modle, pas le modle. Organizational Robbins? Chaque type de diagramme UML possde une structure (les types des lments de modlisation qui le composent sont prdfinis). Peer Paper? Un type de diagramme UML vhicule une smantique prcise (un type de diagramme offre toujours la mme vue d'un systme). On Always Your? Combins, les diffrents types de diagrammes UML offrent une vue complte des aspects statiques et dynamiques d'un systme. Peer Review Research? Par extension et abus de langage, un diagramme UML est aussi un modle (un diagramme modlise un aspect du modle global). II-B-10-b. Essay Teachers? Quelques caractristiques des diagrammes UML^

Les diagrammes UML supportent l'abstraction. Peer Review Form? Leur niveau de dtail caractrise le niveau d'abstraction du modle. To Arms Paper? La structure des diagrammes UML et la notation graphique des lments de modlisation est normalise (document UML notation guide). Peer Review Paper? Rappel : la smantique des lments de modlisation et de leur utilisation est dfinie par le mtamodle UML (document UML semantics). Business? Le recours des outils appropris est un gage de productivit pour la rdaction des diagrammes UML, car : ils facilitent la navigation entre les diffrentes vues, ils permettent de centraliser, organiser, partager, synchroniser et versionner les diagrammes (indispensable avec un processus itratif), facilitent l'abstraction, par des filtres visuels, simplifient la production de documents et autorisent (dans certaines limites) la gnration de code.

II-B-10-c. Review Form? Les diffrents types de diagrammes UML^ Vues statiques du systme : diagrammes de cas d'utilisation diagrammes d'objets diagrammes de classes diagrammes de composants diagrammes de dploiement. Vues dynamiques du systme : diagrammes de collaboration diagrammes de squence diagrammes d'tats-transitions diagrammes d'activits. Les paquetages sont des lments d'organisation des modles. Plan? Ils regroupent des lments de modlisation, selon des critres purement logiques. Peer Form? Ils permettent d'encapsuler des lments de modlisation (ils possdent une interface).

Ils permettent de structurer un systme en catgories (vue logique) et sous-systmes (vue des composants). Business Plan? Ils servent de briques de base dans la construction d'une architecture. Peer? Ils reprsentent le bon niveau de granularit pour la rutilisation. Importance Of Sports? Les paquetages sont aussi des espaces de noms. II-C-1-b.

Paquetages : relations entre paquetages^ II-C-2-a. Review? Symbole de modlisation collaboration^ Les collaborations sont des interactions entre objets, dont le but est de raliser un objectif du systme (c'est--dire aussi de rpondre un besoin d'un utilisateur). Research Paper? L'lment de modlisation UML collaboration, reprsente les classes qui participent la ralisation d'un cas d'utilisation. Attention : ne confondez pas l'lment de modlisation collaboration avec le diagramme de collaboration, qui reprsente des interactions entre instances de classes. II-C-3. Review Form Research? INSTANCES ET DIAGRAMME D'OBJETS ^ Ce type de diagramme UML montre des objets (instances de classes dans un tat particulier) et des liens (relations smantiques) entre ces objets.

Les diagrammes d'objets s'utilisent pour montrer un contexte (avant ou aprs une interaction entre objets par exemple). Independence In India? Ce type de diagramme sert essentiellement en phase exploratoire, car il possde un trs haut niveau d'abstraction. II-C-4-a. Peer Review? Classe : smantique et notation^ Une classe est un type abstrait caractris par des proprits (attributs et mthodes) communes un ensemble d'objets et permettant de crer des objets ayant ces proprits. Classe = attributs + mthodes + instanciation. Il s'agit juste d'un filtre visuel, destin donner un certain niveau d'abstraction son modle.

De mme, ne pas spcifier les niveaux de protection des membres d'une classe ne veut pas dire qu'on ne reprsente que les membres publics. Before Independence In India? L aussi, il s'agit d'un filtre visuel. Documentation d'une classe (niveaux d'abstraction), exemples : Attributs multivalus et drivs, exemples : Classe abstraite, exemple : Template (classe paramtrable), exemple : II-C-5-a. Research Paper? Diagramme de classes : smantique^ Un diagramme de classes est une collection d'lments de modlisation statiques (classes, paquetages. Horse? ), qui montre la structure d'un modle. Peer Review Research? Un diagramme de classes fait abstraction des aspects dynamiques et temporels. Business? Pour un modle complexe, plusieurs diagrammes de classes complmentaires doivent tre construits.

les classes qui participent un cas d'utilisation (cf. Review? collaboration), les classes associes dans la ralisation d'un scnario prcis, les classes qui composent un paquetage, la structure hirarchique d'un ensemble de classes. Organizational Behavior Robbins Attitudes And Job Satisfaction? Pour reprsenter un contexte prcis, un diagramme de classes peut tre instanci en diagrammes d'objets. Une association exprime une connexion smantique bidirectionnelle entre deux classes. Form Paper? L'association est instanciable dans un diagramme d'objets ou de collaboration, sous forme de liens entre objets issus de classes associes. II-C-5-c. To Arms Paper? Documentation d'une association et types d'associations^ Association en forme verbale active : prcise le sens de lecture principal d'une association.

Voir aussi : association navigabilit restreinte. Rles : spcifie la fonction d'une classe pour une association donne (indispensable pour les associations rflexives). Cardinalits : prcise le nombre d'instances qui participent une relation. Relation de dpendance : relation d'utilisation unidirectionnelle et d'obsolescence (une modification de l'lment dont on research paper, dpend, peut ncessiter une mise jour de l'lment dpendant). Association navigabilit restreinte. Par dfaut, une association est navigable dans les deux sens.

La rduction de la porte de l'association est souvent ralise en phase d'implmentation, mais peut aussi tre exprime dans un modle pour indiquer que les instances d'une classe ne connaissent pas les instances d'une autre. Association n-aire : il s'agit d'une association qui relie plus de deux classes. Note : de telles associations sont difficiles dchiffrer et peuvent induire en erreur. On Always? Il vaut mieux limiter leur utilisation, en dfinissant de nouvelles catgories d'associations. Classe d'association : il s'agit d'une classe qui ralise la navigation entre les instances d'autres classes. Qualification : permet de slectionner un sous-ensemble d'objets, parmi l'ensemble des objets qui participent une association.

La restriction de l'association est dfinie par une cl, qui permet de slectionner les objets cibls. Les hirarchies de classes permettent de grer la complexit, en ordonnant les objets au sein d'arborescences de classes, d'abstraction croissante. Dmarche descendante, qui consiste capturer les particularits d'un ensemble d'objets, non discrimins par les classes dj identifies. Peer Review Form Paper? Consiste tendre les proprits d'une classe, sous forme de sous-classes, plus spcifiques (permet l'extension du modle par rutilisation). Dmarche ascendante, qui consiste capturer les particularits communes d'un ensemble d'objets, issus de classes diffrentes. Importance? Consiste factoriser les proprits d'un ensemble de classes, sous forme d'une super-classe, plus abstraite (permet de gagner en gnricit). L'hritage (spcialisation et gnralisation) permet la classification des objets.

Une bonne classification est stable et extensible : ne classifiez pas les objets selon des critres instables (selon ce qui caractrise leur tat) ou trop vagues (car cela gnre trop de sous-classes). Form Research Paper? Les critres de classification sont subjectifs. Of The Liver Paper? Le principe de substitution (Liksow, 1987) permet de dterminer si une relation d'hritage est bien employe pour la classification : Il doit tre possible de substituer n'importe quel instance d'une super-classe, par n'importe quel instance d'une de ses sous-classes, sans que la smantique d'un programme crit dans les termes de la super-classe n'en soit affecte. Peer Review Form Research? Si Y hrite de X, cela signifie que Y est une sorte de X (analogies entre classification et thorie des ensembles). L'agrgation est une association non symtrique, qui exprime un couplage fort et une relation de subordination. Plan? Elle reprsente une relation de type ensemble / lment. Paper? UML ne dfinit pas ce qu'est une relation de type ensemble / lment, mais il permet cependant d'exprimer cette vue subjective de manire explicite. Organizational Behavior Attitudes Satisfaction? Une agrgation peut notamment (mais pas ncessairement) exprimer : qu'une classe (un lment) fait partie d'une autre (l'agrgat), qu'un changement d'tat d'une classe, entrane un changement d'tat d'une autre, qu'une action sur une classe, entrane une action sur une autre. Review Form Research? A un mme moment, une instance d'lment agrg peut tre lie plusieurs instances d'autres classes (l'lment agrg peut tre partag). Farewell Research Paper? Une instance d'lment agrg peut exister sans agrgat (et inversement) : les cycles de vies de l'agrgat et de ses lments agrgs peuvent tre indpendants.

La composition est une agrgation forte (agrgation par valeur). Peer Review Form Research? Les cycles de vies des lments (les composants) et de l'agrgat sont lis : si l'agrgat est dtruit (ou copi), ses composants le sont aussi. Attitudes Satisfaction? A un mme moment, une instance de composant ne peut tre lie qu' un seul agrgat. Peer Research? Les objets composites sont des instances de classes composes. II-C-5-g. Liver Research Paper? Agrgation et composition : rappel^ L'agrgation et la composition sont des vues subjectives. Form Research Paper? Lorsqu'on reprsente (avec UML) qu'une molcule est compose d'atomes, on before independence in india, sous-entend que la destruction d'une instance de la classe Molcule, implique la destruction de ses composants, instances de la classe Atome (cf. Review Form Research Paper? proprits de la composition).

Bien qu'elle ne reflte pas la ralit (rien ne se perd, rien ne se cre, tout se transforme), cette abstraction de la ralit nous satisfait si l'objet principal de notre modlisation est la molcule. Farewell Paper? En conclusion, servez vous de l'agrgation et de la composition pour ajouter de la smantique vos modles lorsque cela est pertinent, mme si dans la ralit de tels liens n'existent pas ! Une interface fournit une vue totale ou partielle d'un ensemble de services offerts par une classe, un paquetage ou un composant. Review Research? Les lments qui utilisent l'interface peuvent exploiter tout ou partie de l'interface. Horse Plan? Dans un modle UML, le symbole interface sert identifier de manire explicite et symbolique les services offerts par un lment et l'utilisation qui en est faite par les autres lments. Les associations drives sont des associations redondantes, qu'on peut dduire d'une autre association ou d'un ensemble d'autres associations.

Elles permettent d'indiquer des chemins de navigation calculs, sur un diagramme de classes. Peer Review Form? Elles servent beaucoup la comprhension de la navigation (comment joindre telles instances d'une classe partir d'une autre). II-C-5-j. Your Teachers? Contrainte sur une association^ Les contraintes sont des expressions qui prcisent le rle ou la porte d'un lment de modlisation (elles permettent d'tendre ou prciser sa smantique). Peer Review Form? Sur une association, elles peuvent par exemple restreindre le nombre d'instances vises (ce sont alors des expressions de navigation).

Les contraintes peuvent s'exprimer en langage naturel. Behavior Robbins Attitudes? Graphiquement, il s'agit d'un texte encadr d'accolades. UML formalise l'expression des contraintes avec OCL (Object Constraint Language). Review Form Research Paper? OCL est une contribution d'IBM UML 1.1. Essay Respect Your Teachers? Ce langage formel est volontairement simple d'accs et possde une grammaire lmentaire (OCL peut tre interprt par des outils). Paper? Il reprsente un juste milieu, entre langage naturel et langage mathmatique. On Always Teachers? OCL permet ainsi de limiter les ambiguts, tout en restant accessible. Peer Review Form Paper? OCL permet de dcrire des invariants dans un modle, sous forme de pseudo-code : pr et post-conditions pour une opration, expressions de navigation, expressions boolennes, etc. Of Sports? OCL est largement utilis dans la dfinition du mtamodle UML. Nous allons nous baser sur une tude de cas, pour introduire brivement OCL.

Monsieur Formulain, directeur d'une chane d'htels, vous demande de concevoir une application de gestion pour ses htels. Form Paper? Voici ce que vous devez modliser : Un htel Formulain est constitu d'un certain nombre de chambres. Essay On Always Respect? Un responsable de l'htel gre la location des chambres. Review Form Research Paper? Chaque chambre se loue un prix donn (suivant ses prestations). L'accs aux salles de bain est compris dans le prix de la location d'une chambre. Horse Business? Certaines chambres comportent une salle de bain, mais pas toutes. Review Form Paper? Les htes de chambres sans salle de bain peuvent utiliser une salle de bain sur le palier.

Ces dernires peuvent tre utilises par plusieurs htes. Les pices de l'htel qui ne sont ni des chambres, ni des salles de bain (hall d'accueil, cuisine. Organizational And Job? ) ne font pas partie de l'tude (hors sujet). Des personnes peuvent louer une ou plusieurs chambres de l'htel, afin d'y rsider. Research Paper? En d'autre termes : l'htel hberge un certain nombre de personnes, ses htes (il s'agit des personnes qui louent au moins une chambre de l'htel. Importance Of Sports Essay? ). Le diagramme UML ci-dessous prsente les classes qui interviennent dans la modlisation d'un htel Formulain, ainsi que les relations entre ces classes. Attention : le modle a t rduit une vue purement statique.

La dynamique de l'interaction entre instances n'est pas donne ici, pour simplifier l'exemple. Peer Paper? Lors d'une modlisation complte, les vues dynamiques complmentaires ne devraient pas tre omises (tout comme la conceptualisation pralable par des use cases). Remarque : cet exemple est inspir d'un article paru dans JOOP (Journal of before in india, Object Oriented Programming), en mai 99. OCL permet d'enrichir ce diagramme, en dcrivant toutes les contraintes et tous les invariants du modle prsent, de manire normalise et explicite ( l'intrieur d'une note rattache un lment de modlisation du diagramme). Voici quelques exemples de contraintes qu'on pourrait dfinir sur ce diagramme, avec la syntaxe OCL correspondante. Les exemples de syntaxe OCL ci-dessous ne sont pas dtaills, rfrez-vous au document de la norme UML adquat (OCL spcification). Research? Il ne s'agit l que d'un trs rapide aperu du pouvoir d'abstraction d'OCL. Les strotypes permettent d'tendre la smantique des lments de modlisation : il s'agit d'un mcanisme d'extensibilit du mtamodle d'UML. Independence In India? Les strotypes permettent de dfinir de nouvelles classes d'lments de modlisation, en plus du noyau prdfini par UML. Review Research Paper? Utilisez les strotypes avec modration et de manire concerte (notez aussi qu'UML propose de nombreux strotypes standards).

II-C-6. Before Independence In India Essay? DIAGRAMMES DE COMPOSANTS ET DE DEPLOIEMENT^ Les diagrammes de composants permettent de dcrire l'architecture physique et statique d'une application en terme de modules : fichiers sources, librairies, excutables, etc. Ils montrent la mise en oeuvre physique des modles de la vue logique avec l'environnement de dveloppement. Peer Form Research? Les dpendances entre composants permettent notamment d'identifier les contraintes de compilation et de mettre en vidence la rutilisation de composants. Importance Essay? Le composants peuvent tre organiss en paquetages, qui dfinissent des sous-systmes. Review Form? Les sous-systmes organisent la vue des composants (de ralisation) d'un systme. Respect? Ils permettent de grer la complexit, par encapsulation des dtails d'implmentation.

Diagramme de composants (exemple) : Les diagrammes de dploiement montrent la disposition physique des matriels qui composent le systme et la rpartition des composants sur ces matriels. Review Research Paper? Les ressources matrielles sont reprsentes sous forme de noeuds. Essay? Les noeuds sont connects entre eux, l'aide d'un support de communication. La nature des lignes de communication et leurs caractristiques peuvent tre prcises. Peer Review Paper? Les diagrammes de dploiement peuvent montrer des instances de noeuds (un matriel prcis), ou des classes de noeuds. Of Sports? Les diagrammes de dploiement correspondent la vue de dploiement d'une architecture logicielle (vue 4+1). II-D-1-a. Review Form Research? La conceptualisation : rappel^

Le but de la conceptualisation est de comprendre et structurer les besoins du client. Robbins And Job Satisfaction? Il ne faut pas chercher l'exhaustivit, mais clarifier, filtrer et organiser les besoins ! Une fois identifis et structurs, ces besoins : dfinissent le contour du systme modliser (ils prcisent le but atteindre), permettent d'identifier les fonctionnalits principales (critiques) du systme. Form Research? Le modle conceptuel doit permettre une meilleure comprhension du systme. Attitudes And Job Satisfaction? Le modle conceptuel doit servir d'interface entre tous les acteurs du projet. Review Form? Les besoins des clients sont des lments de traabilit dans un processus intgrant UML. Il s'agit de la solution UML pour reprsenter le modle conceptuel. Organizational Behavior Robbins Attitudes Satisfaction? Les use cases permettent de structurer les besoins des utilisateurs et les objectifs correspondants d'un systme. Peer Research Paper? Ils centrent l'expression des exigences du systme sur ses utilisateurs : ils partent du principe que les objectifs du systme sont tous motivs. Cirrhosis? Ils se limitent aux proccupations relles des utilisateurs ; ils ne prsentent pas de solutions d'implmentation et ne forment pas un inventaire fonctionnel du systme. Peer Review Form Research? Ils identifient les utilisateurs du systme (acteurs) et leur interaction avec le systme.

Ils permettent de classer les acteurs et structurer les objectifs du systme. Farewell To Arms Paper? Ils servent de base la traabilit des exigences d'un systme dans un processus de dveloppement intgrant UML. Il tait une fois. Le modle conceptuel est le type de diagramme UML qui possde la notation la plus simple ; mais paradoxalement c'est aussi celui qui est le plus mal compris ! Au dbut des annes 90, Ivar Jacobson (inventeur de OOSE, une des mthodes fondatrices d'UML) a t nomm chef d'un norme projet informatique chez Ericsson. Form Paper? Le hic, c'est que ce projet tait rapidement devenu ingrable, les ingnieurs d'Ericsson avaient accouch d'un monstre. Essay On Always Your? Personne ne savait vraiment quelles taient les fonctionnalits du produit, ni comment elles taient assures, ni comment les faire voluer. Classique lorsque les commerciaux promettent monts et merveilles tous les clients qu'ils dmarchent, sans se soucier des contraintes techniques, que les clients ne savent pas exprimer leurs besoins et que les ingnieurs n'ont pas les ressources pour dvelopper le mouton cinq pattes qui rsulte de ce chaos. Pour viter de foncer droit dans un mur et mener bien ce projet critique pour Ericsson, Jacobson a eu une ide.

Plutt que de continuer construire une tour de Babel, pourquoi ne pas remettre plat les objectifs rels du projet ? En d'autres termes : quels sont les besoins rels des clients, ceux qui conditionneront la russite du projet ? Ces besoins critiques, une fois identifis et structurs, permettront enfin de cerner ce qui est important pour la russite du projet. Le bnfice de cette dmarche simplificatrice est double. Paper? D'une part, tous les acteurs du projet ont une meilleure comprhension du systme dvelopper, d'autre part, les besoins des utilisateurs, une fois clarifis, serviront de fil rouge, tout au long du cycle de dveloppement. A chaque itration de la phase d'analyse, on importance essay, clarifie, affine et valide les besoins des utilisateurs ; chaque itration de la phase de conception et de ralisation, on form, veille la prise en compte des besoins des utilisateurs et chaque itration de la phase de test, on cirrhosis paper, vrifie que les besoins des utilisateurs sont satisfaits. Simple mais gnial.

Pour la petite histoire, sachez que grce cette dmarche initie par Jacobson, Ericsson a russi mener bien son projet et a gagn une notorit internationale dans le march de la commutation. Morale de cette histoire : La dtermination et la comprhension des besoins sont souvent difficiles car les intervenants sont noys sous de trop grandes quantits d'informations. Form Paper? Or, comment mener bien un projet si l'on ne sait pas o l'on va ? Conclusion : il faut clarifier et organiser les besoins des clients (les modliser). Un modle est une simplification de la ralit. Liver Paper? Il permet de mieux comprendre le systme qu'on doit dvelopper. Peer Review Research Paper? Les meilleurs modles sont proches de la ralit.

Les use cases, permettent de modliser les besoins des clients d'un systme et doivent aussi possder ces caractristiques. Ils ne doivent pas chercher l'exhaustivit, mais clarifier, filtrer et organiser les besoins ! dfinissent le contour du systme modliser (ils prcisent le but atteindre), permettent d'identifier les fonctionnalits principales (critiques) du systme. Les use cases ne doivent donc en aucun cas dcrire des solutions d'implmentation. Horse? Leur but est justement d'viter de tomber dans la drive d'une approche fonctionnelle, o l'on liste une litanie de fonctions que le systme doit raliser. Bien entendu, rien n'interdit de grer l'aide d'outils (Doors, Requisite Pro, etc. Peer Review Paper? ) les exigences systmes un niveau plus fin et d'en assurer la traabilit, bien au contraire.

Mais un modle conceptuel qui identifie les besoins avec un plus grand niveau d'abstraction reste indispensable. Importance Essay? Avec des systmes complexes, filtrer l'information, la simplifier et mieux l'organiser, c'est rendre l'information exploitable. Peer Review Form Research Paper? Produisez de l'information phmre, complexe et confuse, vous obtiendrez un joyeux dsordre (pour rester poli). Utilisez les use cases tels qu'ils ont t pens par leurs crateurs ! UML est issu du terrain. Importance? Si vous utilisez les use cases sans avoir en tte la dmarche sous-jacente, vous n'en tirerez aucun bnfice. II-D-1-c. Peer Review Paper? Elments de base des cas d'utilisation^ L'acteur peut consulter ou modifier l'tat du systme. Of Sports? En rponse l'action d'un acteur, le systme fournit un service qui correspond son besoin. Peer Form Paper? Les acteurs peuvent tre classs (hirarchiss).

Les uses cases peuvent tre structurs. Of The Research Paper? Les uses cases peuvent tre organiss en paquetages (packages). Peer Review Form Paper? L'ensemble des use cases dcrit les objectifs (le but) du systme. Cas d'utilisation standard : Les diagrammes de collaboration montrent des interactions entre objets (instances de classes et acteurs). Farewell Paper? Ils permettent de reprsenter le contexte d'une interaction, car on paper, peut y prciser les tats des objets qui interagissent. II-D-2-a. Research? Synchronisation des messages^ UML permet de spcifier de manire trs prcise l'ordre et les conditions d'envoi des messages sur un diagramme dynamique.

Pour chaque message, il est possible d'indiquer : les clauses qui conditionnent son envoi, son rang (son numro d'ordre par rapport aux autres messages), sa rcurrence, ses arguments. pr : prdcesseurs (liste de numros de squence de messages spars par une virgule ; voir aussi sq). Indique que le message courant ne sera envoy que lorsque tous ses prdcesseurs le seront aussi (permet de synchroniser l'envoi de messages). Peer Review Form Paper? cond : garde, expression boolenne. Permet de conditionner l'envoi du message, l'aide d'une clause exprime en langage naturel. Plan? sq : numro de squence du message. Indique le rang du message, c'est--dire son numro d'ordre par rapport aux autres messages.

Les messages sont numrots la faon de chapitres dans un document, l'aide de chiffres spars par des points. Peer Paper? Ainsi, il est possible de reprsenter le niveau d'embotement des messages et leur prcdence. Exemple : l'envoi du message 1.3.5 suit immdiatement celui du message 1.3.4 et ces deux messages font partie du flot (de la famille de messages) 1.3. Pour reprsenter l'envoi simultan de deux messages, il suffit de les indexer par une lettre. Exemple : l'envoi des messages 1.3.a et 1.3.b est simultan. Plan? iter : rcurrence du message. Permet de spcifier en langage naturel l'envoi squentiel (ou en parallle, avec ||) de messages. Peer? Notez qu'il est aussi possible de spcifier qu'un message est rcurrent en omettant la clause d'itration (en n'utilisant que * ou *||). Importance Of Sports? r : valeur de retour du message.

Permet d'affecter la valeur de retour d'un message, pour par exemple la retransmettre dans un autre message, en tant que paramtre. Review Paper? msg : nom du message. On Always Respect Your? par : paramtres (optionnels) du message. UML permet de reprsenter des communications entre objets actifs de manire concurrente. Peer Review Form Research Paper? Cette extension des diagrammes de collaboration permet notamment de reprsenter des communications entre processus ou l'excution de threads. II-D-3-a. Behavior And Job? Diagramme de squence : smantique^ Les diagrammes de squences permettent de reprsenter des collaborations entre objets selon un point de vue temporel, on peer review form research paper, y met l'accent sur la chronologie des envois de messages. Essay On Always Respect Your Teachers? Contrairement au diagramme de collaboration, on peer review form, n'y dcrit pas le contexte ou l'tat des objets, la reprsentation se concentre sur l'expression des interactions. Independence Essay? Les diagrammes de squences peuvent servir illustrer un cas d'utilisation.

L'ordre d'envoi d'un message est dtermin par sa position sur l'axe vertical du diagramme ; le temps s'coule de haut en bas de cet axe. Peer? La disposition des objets sur l'axe horizontal n'a pas de consquence pour la smantique du diagramme. Independence Essay? Les diagrammes de squences et les diagrammes d'tat-transitions sont les vues dynamiques les plus importantes d'UML. Comme vous pouvez le voir dans l'exemple ci-dessus, UML propose un certain nombre de strotypes graphiques pour dcrire la nature du message (ces strotypes graphiques s'appliquent galement aux messages des diagrammes de collaborations) : Message dont on peer review research paper, ne spcifie aucune caractristique d'envoi ou de rception particulire. On Always? message minut (timeout) Bloque l'expditeur pendant un temps donn (qui peut tre spcifi dans une contrainte), en attendant la prise en compte du message par le rcepteur. Peer? L'expditeur est libr si la prise en compte n'a pas eu lieu pendant le dlai spcifi. Of The Research Paper? message synchrone. Bloque l'expditeur jusqu' prise en compte du message par le destinataire. Review Paper? Le flot de contrle passe de l'metteur au rcepteur (l'metteur devient passif et le rcepteur actif) la prise en compte du message. Farewell To Arms Research Paper? message asynchrone.

N'interrompt pas l'excution de l'expditeur. Research Paper? Le message envoy peut tre pris en compte par le rcepteur tout moment ou ignor (jamais trait). Essay On Always Respect Your Teachers? message drobant. N'interrompt pas l'excution de l'expditeur et ne dclenche une opration chez le rcepteur que s'il s'est pralablement mis en attente de ce message. Sur un diagramme de squence, il est aussi possible de reprsenter de manire explicite les diffrentes priodes d'activit d'un objet au moyen d'une bande rectangulaire superpose la ligne de vie de l'objet. On peut aussi reprsenter des messages rcursifs, en ddoublant la bande d'activation de l'objet concern. Pour reprsenter de manire graphique une excution conditionnelle d'un message, on peer form research, peut documenter un diagramme de squence avec du pseudo-code et reprsenter des bandes d'activation conditionnelles. Ne confondez la priode d'activation d'un objet avec sa cration ou sa destruction. Essay On Always Respect? Un objet peut tre actif plusieurs fois au cours de son existence (voir exemple ci-dessus). Peer Review Form Research Paper? Le pseudo-code peut aussi tre utilis pour indiquer des itrations (avec incrmentation d'un paramtre d'un message par exemple). Of Sports Essay? Le retour des messages asynchrones devrait toujours tre matrialis, lorsqu'il existe. Review Form Paper? Notez qu'il est fortement recommand de synchroniser vos messages, comme sur l'exemple qui suit.

L'exemple qui suit prsente aussi une alternative intressante pour la reprsentation des branchements conditionnels. Business? Cette notation est moins lourde que celle utilise dans l'exemple ci-dessus. Research Paper? Prfrez aussi l'utilisation de contraintes celle de pseudo-code, comme dans l'exemple qui suit. Afin de mieux comprendre l'exemple ci-dessous, veuillez vous rfrer aux chapitres sur la synchronisation des messages. Satisfaction? Notez aussi l'utilisation des contraintes pour documenter les conditions d'envoi de certains messages. Un message rflexif ne reprsente pas l'envoi d'un message, il reprsente une activit interne l'objet (qui peut tre dtaille dans un diagramme d'activits) ou une abstraction d'une autre interaction (qu'on peut dtailler dans un autre diagramme de squence).

II-D-4-a. Peer Review Form Research? Diagramme d'tats-transitions : smantique^ Ce diagramme sert reprsenter des automates d'tats finis, sous forme de graphes d'tats, relis par des arcs orients qui dcrivent les transitions. Before Essay? Les diagrammes d'tats-transitions permettent de dcrire les changements d'tats d'un objet ou d'un composant, en rponse aux interactions avec d'autres objets/composants ou avec des acteurs. Form Research Paper? Un tat se caractrise par sa dure et sa stabilit, il reprsente une conjonction instantane des valeurs des attributs d'un objet. Organizational Behavior Robbins And Job Satisfaction? Une transition reprsente le passage instantan d'un tat vers un autre.

Une transition est dclenche par un vnement. Review Form? En d'autres termes : c'est l'arrive d'un vnement qui conditionne la transition. Business Plan? Les transitions peuvent aussi tre automatiques, lorsqu'on ne spcifie pas l'vnement qui la dclenche. Review? En plus de spcifier un vnement prcis, il est aussi possible de conditionner une transition, l'aide de gardes : il s'agit d'expressions boolennes, exprimes en langage naturel (et encadres de crochets). tats, transition et vnement, notation : II-D-4-b. Business? Super-Etat, historique et souches^ Un super-tat est un lment de structuration des diagrammes d'tats-transitions (il s'agit d'un tat qui englobe d'autres tats et transitions).

Le symbole de modlisation historique, mmorise le dernier sous-tat actif d'un super-tat, pour y revenir directement ultrieurement. Le diagramme d'tats-transitions ci-dessous, montre les diffrents tats par lesquels passe une machine laver les voitures. En phase de lustrage ou de lavage, le client peut appuyer sur le bouton d'arrt d'urgence. Review Research? S'il appuie sur ce bouton, la machine se met en attente. Respect? Il a alors deux minutes pour reprendre le lavage ou le lustrage (la machine continue en phase de lavage ou de lustrage, suivant l'tat dans lequel elle a t interrompue), sans quoi la machine s'arrte. Review Form Paper? En phase de schage, le client peut aussi interrompre la machine. Essay Respect Teachers? Mais dans ce cas, la machine s'arrtera dfinitivement (avant de reprendre un autre cycle entier).

On peut aussi associer une action l'vnement qui dclenche une transition. La syntaxe est alors la suivante : vnement / action Ceci exprime que la transition (dclenche par l'vnement cit) entrane l'excution de l'action spcifie sur l'objet, l'entre du nouvel tat. Exemple : il pleut / ouvrir parapluie Une action correspond une opration disponible dans l'objet dont on review, reprsente les tats. Essay On Always? Les actions propres un tat peuvent aussi tre documentes directement l'intrieur de l'tat. UML dfinit un certain nombre de champs qui permettent de dcrire les actions dans un tat : entry / action : action excute l'entre de l'tat exit / action : action excute la sortie de l'tat on form, vnement / action : action excute chaque fois que l'vnement cit survient do / action : action rcurrente ou significative, excute dans l'tat. Attention, les actions attaches aux clauses entry et exit ne sont pas excutes si l'vnement spcifi dans la clause on essay on always, survient. Peer Review Form? Pour indiquer qu'elles peuvent tre excutes plusieurs fois l'arrive d'un vnement, reprsentez l'arrive d'un vnement rflexif, comme suit : II-D-4-d. Behavior Attitudes? Etats concurrents et barre de synchronisation^ Pour reprsenter des tats concurrents sur un mme diagramme d'tats-transitions, on peer review form paper, utilise la notation suivante : Dans l'exemple ci-dessus, l'automate K est compos des sous-automates L et M. L et M s'activent simultanment et voluent en parallle. Farewell? Au dpart, l'objet dont on peer review paper, modlise les tats par l'automate K est dans l'tat composite (E-L1, E-M1).

Aprs l'vnement Tr1, K passe dans l'tat composite (E-L2, E-M2). Importance Essay? Par la suite, si l'vnement Tr2 survient, K passe dans l'tat composite (E-L3, E-M2). Peer Review Research Paper? Si c'est Tr4 qui survient, M ne passe pas dans l'tat E-M1, car cette transition est contrainte par l'tat de L ([in E-L3]). Dans l'tat composite (E-L3, E-M2), si Tr3 survient, K passe dans l'tat composite (E-L2, E-M2). Paper? Si c'est Tr4 qui survient, K passe dans l'tat composite (E-L3, E-M1). Peer Paper? Et ainsi de suite. Attention : la numrotation des vnements n'est pas significative.

Pour synchroniser les sous-automates d'une agrgation d'tats, il faut contraindre les transitions, comme dans l'exemple ci-dessus ([in E-L3]). La barre de synchronisation permet de reprsenter graphiquement des points de synchronisation. Behavior Robbins Attitudes Satisfaction? Les transitions automatiques qui partent d'une barre de synchronisation ont lieu en mme temps. Peer Review? On ne franchit une barre de synchronisation qu'aprs ralisation de toutes les transitions qui s'y rattachent. UML permet aussi de paramtrer les vnements, comme dans l'exemple suivant : II-D-4-f. Cirrhosis Liver Paper? Echange de messages entre automates^ Il est aussi possible de reprsenter l'change de messages entre automates dans un diagramme d'tats-transitions. Form? Cette notation particulire n'est pas prsente ici. Robbins And Job Satisfaction? Veuillez vous rfrer l'UML notation guide. II-D-5-a.

Diagramme d'activits : smantique^ UML permet de reprsenter graphiquement le comportement d'une mthode ou le droulement d'un cas d'utilisation, l'aide de diagrammes d'activits (une variante des diagrammes d'tats-transitions). Peer Review? Une activit reprsente une excution d'un mcanisme, un droulement d'tapes squentielles. Before Independence In India Essay? Le passage d'une activit vers une autre est matrialis par une transition. Peer? Les transitions sont dclenches par la fin d'une activit et provoquent le dbut immdiat d'une autre (elles sont automatiques). Organizational Behavior Robbins Satisfaction? En thorie, tous les mcanismes dynamiques pourraient tre dcrits par un diagramme d'activits, mais seuls les mcanismes complexes ou intressants mritent d'tre reprsents. activits et transition, notation : Pour reprsenter des transitions conditionnelles, utilisez des gardes (expressions boolennes exprimes en langage naturel), comme dans l'exemple suivant : Il est possible de synchroniser les transitions l'aide des barres de synchronisation (comme dans les diagrammes d'tats-transitions). Les transitions qui partent d'une barre de synchronisation ont lieu en mme temps. Peer Review Paper? On ne franchit une barre de synchronisation qu'aprs ralisation de toutes les transitions qui s'y rattachent. L'exemple suivant illustre l'utilisation des barres de synchronisation : Afin d'organiser un diagramme d'activits selon les diffrents responsables des actions reprsentes, il est possible de dfinir des couloirs d'activits.

Il est mme possible d'identifier les objets principaux, qui sont manipuls d'activits en activits et de visualiser leur changement d'tat. Programmer en C++ n'est pas concevoir objet ! Seule une analyse objet conduit une solution objet (il faut respecter les concepts de base de l'approche objet). Cirrhosis Research Paper? Le langage de programmation est un moyen d'implmentation, il ne garantit pas le respect des concepts objet. Review Form? UML n'est qu'un support de communication ! L'utilisation d'UML ne garantit pas le respect des concepts objet : vous de vous en servir bon escient. Concevoir objet, c'est d'abord concevoir un modle qui respecte les concepts objet ! Le langage et UML ne sont que des outils.

Multipliez les vues sur vos modles ! Un diagramme n'offre qu'une vue trs partielle et prcise d'un modle. Of The Liver? Croisez les vues complmentaires (dynamiques / statiques). Review Form Research Paper? Restez simple ! Utilisez les niveaux d'abstraction pour synthtiser vos modles (ne vous limitez pas aux vues d'implmentation). Essay Respect Your? Ne surchargez pas vos diagrammes. Peer Review? Commentez vos diagrammes (notes, texte. Cirrhosis Of The Research? ). Research? Utilisez des outils appropris pour raliser vos modles ! Vous avez aim ce tutoriel ? Alors partagez-le en cliquant sur les boutons suivants : Copyright 2007 Laurent Piechocki. Before Independence Essay? Aucune reproduction, même partielle, ne peut être faite de ce site et de l'ensemble de son contenu : textes, documents, images, etc. Peer Review Form? sans l'autorisation expresse de l'auteur.

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Literary Analysis Essay: 1984 by peer form research George Orwell. “No one is free, even the birds are chained to the sky.” Bob Dylan said this probably not knowing its profound connection with George Orwell’s novel “1984”, but the as well could be in cirrhosis liver research “1984”. Orwell depicts a totalitarian dystopian world where there is no freedom and citizens are being brainwashed constantly. Without any sense of individual fairness, people work for paper the party just like the gear wheels in a machine. Organizational Robbins Satisfaction! In order to achieve this, the politicians in review form “1984” suppress people’s thinking and eliminate their freedom by creating fear through propaganda, strict laws and incessant surveillances. In “1984”, lies, myths and false information controls the thinking of the liver research, citizens. The Party uses propaganda as the deadliest weapon of control.

Propaganda increases the citizens’ morale and makes them think that what the party tells them to peer research do is organizational behavior robbins satisfaction always right. There are mainly two types of propaganda, one changes truth, so-called doublethink, and peer review research paper, another creates fear. “Doublespeak” can be seen frequently in the world of 1984. The party’s big slogan “WAR IS PEACE. Of Sports! FREEDOM IS SLAVERY. IGNORANCE IS STRENGTH.” (George Orwell, 4) is an good example. The idea of the slogan is to convince the citizens that what they want, is what they already have. Only war can make peace and harmony, so peace is no longer peace, it becomes war; anyone who is slaved and wants freedom, he already has freedom; you can only strengthen yourself by not knowing things and being ignorant. The slogan changes truth and make the research paper, citizens believe that anything they want other than what their government wants can only make them unhappy, therefore, no one will consider rebellion because they believe the Party’s way of essay on always respect, governing is the best and peer form research, only way. Behavior Robbins And Job Satisfaction! “BIG BROTHER IS WATCHING YOU” (George Orwell, 3) is review paper another core slogan.

It is nearly everywhere in essay the country and usually presented beneath the picture of Big Brother on a poster. It creates fear of obliterated privacy among citizens by alerting them that they are watched all the time. At the same time, the slogan also emphasizes Big Brother’s power to tells the citizens that they are indeed safe and protected. The party uses this to make them believe that within the peer review research, party nothing can go wrong, and without Big Brother they will not have such lives. Before In India! Everyone thinks he is safe in Oceania because of the peer review form research paper, Big Brother, but they are in fact in danger, all the time.

The laws is another powerful tool for politicians in before in india “1984” to limit citizens freedom. No parties, no dates, no love, no citizens walk on street after curfew, laws are everywhere in peer form research paper Oceania. Although these are strictly implemented, they cannot be called laws theoretically because they are not written in a system. There is no written laws in 1984, there is no such thing as constitution or court, but that is exactly how fear is created, as citizens are always living in uncertainty. For example, “And yet it was a fact that if Syme grasped, even for three seconds, the nature of his, Winston#8217;s, secret opinions, he would betray him instantly to essay on always your teachers the Thought Police” (George Orwell, 30). There is peer review form no law that defines thoughtcrime However, Winston could be arrested any time for committing thoughtcrime by even a tiny facial twitch suggesting struggle, and his nervous system literally becomes his biggest enemy. Since there is no written law, the Party can change and adjust the strictness of laws freely as it wants, citizens never know if they have committed any crime, therefore no one is brave enough to defy the Party by farewell to arms research any level, so fear is created. In addition, “Newspeak” is another law that is paper enforced to solidify the Party’s control. Humans use language to express their ideas, by eliminating words and replacing emotional words such as “excellent”, “wonderful” and “fantastic” by horse plan a single word “good” and its comparative degrees “plusgood” and “plusplusgood”. Lots of thoughts are actually limited because they cannot be formed linguistically in people’s mind. Citizens then cannot have their own critical thinking, and only do what they are told to do, they work just as computers, which surprisingly only have two words.* Surveillance is almost everywhere in Oceania, the mostly used way is television.

There is a two-way screen, so-called television in peer review form research paper every apartment and on street but they only serve the robbins attitudes and job, purpose of monitoring and propaganda, the Party gets simultaneous image of what its people are doing. Peer Review Paper! Even facial expression can be detected. Only senior members of the Inner Party have the essay on always respect your, power to peer form research turn them off for a short period. Children are also used to keep track of their parents, “The children, on the other hand, were systematically turned against their parents and taught to spy on them and report their deviations” (76). In fact, this was used by the communist party of China during Cultural revolution.

With extremely mighty surveillance, citizens cannot express their ideas towards the negative side of the Party at all, and even thoughts are controlled because the Party can “reeducate” people for an incorrect facial expression. By using language as a tool of control as well as the evidence for organizational behavior sentence, Orwell creates a world where language, a word or a sentence, can determine ones life. Through language plays the key role in the Party’s propaganda, strict laws and review, surveillance, total physical control as well as phycological manipulation is achieved. In Oceania, thoughts are suppressed until them vanish after generations. Importance Of Sports Essay! In this world, nothing is free, even a bird. *0 and 1, Binary numeral system.

Bibliography: Orwell, George. 1984 . San Diego: Harcourt Brace Jovanovich, 1984. Print.

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comedy divine essay The Mafia is oppression, arrogance, greed, self-enrichment, power and peer review form research paper, hegemony above and against all others. It is not an abstract concept, or a state of essay on always mind, or a literary term. It is a criminal organization regulated by unwritten but iron and inexorable rules. The myth of a courageous and generous 'man of honor' must be destroyed, because a mafioso is just the opposite. -- Cesare Terranova, Italian Magistrate murdered in 1979. It exists. It is a symptom of Sicily's endemic political corruption and a general cynicism regarding public institutions and the criminal justice system, its life sustained by a widespread mentality which breeds a general distrust in review research paper even the farewell to arms, youngest Sicilians - distrust of everybody and every thing. The people who claim or imply that the international Mafia does not exist or is not very powerful (and that unfortunately has included one or two Italian-American ethnic organisations despite news of the Mafia in American publications such as Time and Newsweek ) are either in denial, intentionally deceptive, self-serving or plain ignorant. Four pervasive myths about the Sicilian Mafia - as opposed to the American, Calabrian, Apulian or Neapolitan forms of organized crime - should be dispelled. • The Mafia has a centralized organizational structure with a single man at the top, like a Pope.

This has never been true, although one infamous mafioso was indeed nicknamed The Pope. Vizzini, Genco Russo, Greco, Riina, Provenzano, Lo Piccolo and (now) Messina Denaro never controlled the peer review paper, entire Sicilian Mafia, which has been compared to a hydra or octopus. At best, they briefly, informally oversaw the cupola or commission that administers it loosely and your, collectively, but which would never risk regular meetings. Peer Review Paper? There is organizational behavior and job not, and never has been, a true capo dei capi (head of review paper heads) of the Mafia or the of sports, Camorra (the Neapolitan brand of organized crime) in the manner of review a Pope, CEO or general at of sports, the head of a rigidly structured organization. It is for peer research this reason that decapitation is impossible. Italian investigators and prosecutors know this, yet they also know that less-important mafia bosses tacitly defer to more powerful ones, especially in certain matters involving foreign (international) business or, for example, the murder of of sports a high-profile figure like a judge or senator.

Within each cosca or cell, of review research course, there are ranks. • The Mafia is hereditary, based on families. Times change, but until the 1950s the Sicilian Mafia was not based on families but simply on farewell to arms geographical zones of influence (Palermo, Catania, Corleone). Calogero Vizzini, Michele Greco, Salvatore Totò Riina and peer review research, Tommaso Buscetta were not the sons or near relatives of mafiosi. However, the Italianate forms of Mafia that flourish outside Sicily eventually developed a hereditary system of leadership. On Always Teachers? That includes mainland Italy and research, the Americas. In the United States, there historically was a blurry cultural distinction between the in india essay, true Mafia of Lucky Luciano and the gangsterism of Al Capone. Research? The cosche (literally but inaccurately clans) are not actual families but local territorial cells which include many people, of various ranks, who are unrelated to each other.

That said, nowadays it isn't too unusual for a young mafioso to wed the sister or cousin of a fellow mafioso, or for the leader of a cosca to importance, favor his own son with a certain benefit, such as extorting the pizzo in a specific neighborhood. There have also been cases of the wives of incarcerated mafiosi managing their husbands' affairs, including murder and extortion, especially in Catania. • The Mafia was supported by the nobility and the Catholic Church. By the twentieth century mafiosi were extorting money from aristocrats and by peer review form research, the end of the same century they were killing priests. One might make a case that certain landholding aristocrats and higher clergy, including a few bishops, condoned the of the research, actions of the Mafia when it was expedient, but sweeping generalizations are unjustified.

For example, the land reforms of 1948 dividing the large rural estates were opposed by the nobles who owned these properties, and certain mafiosi worked for peer review form research these landholders as land managers. Until the twentieth century the behavior attitudes and job, Church in Italy rarely took a strong position on any progressive social issue, so (for example) divorce was legalized in the country only in peer paper 1974. If anything, we could say that the Mafia was sometimes facilitated by corrupt politicians who, like most Italians, were Catholic. It is true, however, that the Mafia flourished for a long time because the Church and research paper, the ruling class failed to recognize it as a threat to the very fabric of research society. • The Mafia traces its roots to the Middle Ages. This is horse business perhaps the most ridiculous myth of all. While the peer form paper, closed, secretive mentality that fostered the development of secret criminal societies such as the Beati Paoli became commonplace with the Inquisition and Spanish rule during the sixteenth century, and though banditry in the countryside increased over respect, time, the peer form, Mafia as organized crime (not just a Sicilian word having other meanings) did not exist until late in the eighteenth century at the very earliest. Only fantasists believe that it originated during the importance of sports essay, War of the Vespers, a revolt organized by the nobility, in 1282.

Phenomena such as widespread charlatanry and professional incompetence, nepotism and the overuse of job preferments have helped it along by discouraging transparency at every level of the economy. Until the fifteenth century the feudal life of Sicily was little different from peer review form research paper that of any other part of cirrhosis liver western Europe. The history of the Mafia is not as elusive as pundits, novelists and screenwriters would have you believe. Protection rackets (the pizzo) and the narcotics trade still exist, of course, with the review form research paper, Mafia funnelling its ill-won profits into businesses such as supermarket and hotel chains across Sicily and even in northern Italy. But a phenomenon which has worsened in recent years is the importance, widespread theft of form research paper European Commission funding destined, in principle, for Sicilian economic development. Bribes, kickbacks and outright theft by politicians closely allied with (or actually members of) the Mafia has been a fact of life in Sicily for a long time. The Mafia owns shopping centers, apartment blocks and construction firms that receive public contracts.

It extorts hundreds of millions of euros each year to buy ever more such businesses. In addition to politicians, many lawyers, doctors and farewell research, architects are directly involved with the Mafia. It is peer a cancer that hides for business a while but just won't die. Considering its profound influence on Sicilian life, no history of twentieth-century Sicily can be complete or accurate without mentioning the most famous Sicilian fraternity. Tragically, the Mafia (and extreme political corruption generally) is the single socio-economic factor that distinguishes Sicily's economic base from those of other European Mediterranean regions such as Spain and Portugal - though it appears that Greece also has some serious problems with public spending and corruption. It is one of the world's most enduring criminal organizations, and one of the most serious social problems confronting Sicily today. In recent times, it has murdered judges, priests and children - though with its increasing grip on form research paper the legal economy (public contracts, stores, restaurants) - this rarely happens nowadays. Respect Your? Its hierarchy and vernacular are a reflection of Sicilian society itself, complete with religious allusions: Its ruling council is the Cupola, Michele Greco, was nicknamed The Pope, a leader of clans.

But, like the nobility, the peer form paper, Mafia is all but invisible. Respect Teachers? You probably won't see it if you visit Sicily. You probably won't see many of its effects, either, unless you look very closely. Those who presume that today's Sicilians do not think about the Mafia are sorely mistaken. Anti-Mafia organisations such as Addio Pizzo (of which Best of Sicily is a member) have done much to encourage merchants and other business owners to stand up against the Mafia, but there is still much work to be done. Banditry and peer review form, murder had been fairly commonplace since the Middle Ages, but the Mafia has existed as a loose network of local criminals only business plan, since the latter decades of the eighteenth century or the early years of the nineteenth. Like the nobility, its roots are feudal.

Indeed, the early history of the review form paper, Mafia is well known. Many people incorrectly presume the Mafia to be the of sports essay, cause of certain social problems. In fact, it is the effect - the result of centuries of bizarre practices such as raccomandazioni (job preferments) which colour every facet of life in Sicily, making it a fertile breeding ground for all forms of corruption, dishonesty and criminality. Peer Research? Nepotism (even in university positions) doesn't help matters, either. In such a climate, organised crime represents just one small step beyond the unfortunate conditions that already exist. In Sicily politicians literally buy votes with promises of employment or other gifts.

The popular perception of farewell to arms research paper mafiosi as Robin Hoods or even knights is misleading, but it is based on general distrust of authority and - until very recently - the paper, historical laxity of law enforcement in protecting citizens. Independence Essay? This situation has improved somewhat in peer research paper recent years but still persists among the popolino, Sicily's large underclass. From being friends of the farewell research paper, friends, the more important mafiosi became known as men of honor. In truth, the Mafia code is the antithesis of the code of chivalry - or at best a bizarre interpretation of it. Sicilians' clannish nature (marriages arranged by review form, parents were known into essay respect your the twentieth century) created a favorable climate for the mafiosi. Omertà literally means manhood, and refers to the idea of a man resolving his own problems, but the term has become synonomous with the Mafia's code of silence.

The duel, however, gave way to the vendetta and contract killings. There is no reliable historical record of a duel between mafiosi, but there have been plenty of murders and, given its structure as a secret society. The freemasons certainly aided Garibaldi's invasion of Sicily in 1860 but so, it is believed, did some Mafia bands, even if they were not a decisive factor in his victory. Peer? In the same year, it was suggested to King Francesco II of the Two Sicilies that the Comorra, a Neapolitan organization similar to of the liver research paper, the Mafia, kill Garibaldi and his officers upon their arrival in Naples. The King refused his subjects' offer. incredibly, the plan might have actually worked. The Modern Mafia. A famous play, I Mafiusi della Vicaria, first performed in 1863, described the Mafia as an organization complete with initiation rites, though folk historian Giuseppe Pitré's interpretation of Mafia history has been largely discounted as whimsical or at least highly embellished. By 1900, the black hand was identified with the peer paper, friends of the friends. They were one and the same, and each town (or city quarter) had its resident capo (chief). When the Fascists rose to power, Mussolini's Iron Prefect, Cesare Mori, threw most of them in prison. Independence In India? In reality, the relationship between the peer research paper, Fascists and the Mafia was that of one group of criminals pitted against another - two wolves fighting over the same chicken coop.

The wartime collaboration of Sicilian-born Salvatore Lucky Luciano with the United States Navy may have made the aftermath of the Allied invasion of Sicily smoother than it otherwise might have been, but there is no evidence that the Sicilians in 1943 were any less welcoming of the Allies than the residents of Piedmont and to arms, Lombardy were two years later. Luciano's real influence was at the Port of New York. The Iron Prefect's enforcement of the Duce's laws had already made most mafiosi sympathetic to the American cause, or at least hostile to the Fascist one. The surrender, without even token resistance, of thousands of Italian troops at peer review form research paper, Pantelleria, shortly before the main attack on before Sicily, made it clear that most Italian recruits were unwilling to risk their lives for a lost cause - or perhaps for any cause. The Allies made mafiosi like Calogero Vizzini, of Villalba, provisional mayors who easily won election a few years later. It was easy for review research these men, imprisoned by essay your, Mussolini's regime without the benefit of review form paper a fair trial, to pose as anti-Fascists or even political prisoners. Under any political system, Vizzini, who died in 1954, was a murderer, plain and simple. In the immediate postwar years, as the Mafia set about the essay on always your, task of re-organizing its activities, several freelance bandits roamed the countryside. The most popular, Salvatore Giuliano, came closest to the image of peer research paper a modern Robin Hood, and supported a separatist movement that favored an horse independent Sicily, perhaps as part of the review research, United States.

Men like Giuliano were not mafiosi. Indeed, the mafiosi resented and perhaps even feared them. With the to arms research paper, death of Calogero Vizzini, the peer review research paper, Mafia slid into the realm of what Sicily's mafiosi later derided as gangsterism, a more reckless American style of crime. In 1957, the Sicilian Mafia re-established ties with their brethren in the United States and Canada. It was Lucky Luciano, of all people, who orchestrated the alliance. Unlike Vizzini and his generation, the new Sicilian men of honor were vastasi (uncouth people) who made no pretension whatsoever at being gentlemen. Whereas, in farewell research paper public at review research paper, least, Vizzini and people like him maintained a veneer of civility, and might even pass for essay dignified country squires, it was clear that newcomers like Giuseppe Genco Russo, Michele Greco and Luciano Leggio, though furbi (sly) in certain respects, were essentially vulgar by peer review form paper, nature.

Men of before in india honor and the code of form research honor, if either had ever existed in fact, vanished in a flurry of murders. By the 1970s, even women and children were not spared in the carnage. While the Mafia controlled building construction (effectively destroying large historical districts) and vast sectors of the economy (the meat trade, for example) and developed a successful heroin trade, the pizzo (extortion through protection money) remained a cornerstone of its system for generating revenue, day-by-day, year after year. As there were not yet laws against organised crime, people such as social activist Danilo Dolci were successfully prosecuted for horse defaming people who they publicly stated were mafiosi, and who in fact were! During the 1960s, the review, Sicilian Cupola and the American Commission began to business plan, seriously cooperate in the narcotics trade, despite their expressed sentiment that heroin and cocaine were somehow less respectable products than extortion and murder. The Sicilian faction was still more ruthless than its American counterpart, often resorting to the murder of peer review form judges and other public officials, as well as journalists, whose activities they considered inconvenient.

Palermo's Falcone-Borsellino Airport is named after two such judges, and there is a monument in Piazza 13 Vittime (13 Victims), at the end of Palermo's Via Cavour, dedicated to to arms paper, the memory of research people killed by the Mafia. Politicians as Mafiosi. In postwar Sicily's larger cities, mafiosi gradually infiltrated the building trades and bought their way into most government-run agencies. Organizational Attitudes And Job Satisfaction? Why are the newer districts of Palermo full of ugly buildings but lacking in peer review paper green parks and efficient parking areas? Because the urban planning was undertaken by of the, criminals. The Mafia, albeit often indirectly, built nearly half of the new city of Palermo, where several corrupt officials literally sold building permits to Mafia front-men. A similar situation emerged in Catania.

And the Mafia built (and still indirectly operates) a few of Sicily's largest hotels. The Catholic Church has not always helped matters. Some priests now speak out against the Mafia (though pastors of Corleone, traditionally a Mafia stronghold, have not usually been among them), and at least one cleric was murdered for doing so. In the 1960s, however, a Cardinal Archbishop of Palermo issued a statement that the Mafia had never existed, and that author Giuseppe di Lampedusa, along with Danilo Dolci, had defamed Sicilians by implying that, among other things, most western Sicilians were secretive by nature or habit, and that the Mafia does indeed exist. How does such an organization survive into form research the twenty-first century? It has a great deal to independence, do with social factors - things like high unemployment, widespread lack of confidence in the competence of law enforcement authorities, distrust of the state.

But the general secretiveness of the people is one of the peer review research paper, main reasons organised crime is still so powerful in the Italian South, where common folk often seem suspicious of even the most ordinary social forces. The Italian ethos is based on the realities of everyday life: Italians presume that their elected leaders are thieves motivated by greed. Businessmen presume that associates will steal at the first opportunity. Labor unions presume that employers will seek to importance, exploit employees whenever possible. Spouses presume that marital infidelity is simply a question of human nature, and even use a particular word, cornuto, to describe cuckolded husbands. As we've said, a large part of certain economic sectors (hotels, transportation, supermarkets, construction) are controlled by Mafiosi. In a land without a tangible industrial base, public monies are the paper, Mafia's main target. Everything has its price. Most politicians (Left and Right) can be bought, and the same holds true for managers of behavior robbins attitudes and job most larger banks and utilities.

In Sicily, many (if not most) public or semi-public jobs are sold for money or - in rarer cases - sex. (An attractive, educated but unemployed young woman is peer review research easy prey in a region with a perpetual 30% unemployment rate.) Public contracts are assigned - actually sold - in exchange for bribes and kickbacks. Everybody expects a substantial kickback (usually at least 10%), from the politician who gets you a public advertising or construction project to the event organizer who gets your musical group a gig in in india essay the local music festival. Research Paper? In business, money laundering is a way of life. It's all part of The New Mafia. Importance Of Sports? In such a climate, the pizzo (protection money) and revenue through legitimate businesses set up with Mafia money are still important. Buying the European Commission. Against such a backdrop, one easily understands that the Mafia is not always the form paper, primary cause of organised crime in Sicily. More often, it is organizational behavior attitudes and job satisfaction a simple symptom of the corruption that permeates almost every aspect of public and professional life in Sicily. New corruption is born every day: In recent years, certain local politicians who have spoken against peer review form research, the Mafia have covertly purchased large sections of Palermo's historical district through front companies (there were no public auctions), and independence in india, given well-paying consulting jobs to their friends and relations.

Sicilians call it mafiosità , the Mafia-like mentality so prevalent in peer review paper Sicilian life, especially among politicians and business people. This doesn't always mean that somebody is a mafioso per se, just that he behaves like one. Mafiosetta is the Sicilian term for an attractive young woman who acts in this way. Clientelism, nepotism and the excessive use of recommendations to on always respect teachers, assign everything from public construction contracts to peer review research, clerical jobs foster widespread corruption, and therefore organised crime. Bribery and kickbacks (the Italian word is bustarella for cirrhosis of the paper the envelope, busta, in peer review research paper which the money is paid) are normal in Sicily.

Billions of dollars poured into on always teachers the Sicilian economy by the World Bank, the United States, the European Commission and the central Italian government have ended up in the hands of peer review form paper corrupt politicians, consultants and others who, in many instances, were connected to the Mafia in farewell research paper some way. In many cases, the children or grandchildren of Mafiosi and Mafia-collaborators who stole money earmarked for Sicilian development under the peer form, Marshall Plan decades ago are now respectable citizens who one would not overtly associate with organised crime. In other words, the families have become legitimate. To many Sicilians, wealth is viewed as an end in itself; the methods employed to on always respect your teachers, gain it are of peer review form paper little importance so long as misdeeds go unpunished. It's no secret that the criminal justice system does not function very well in before essay Italy. And where there is no law, there is no sin.

The sale of jobs is not limited to banks, national companies (telecommunications, energy, airlines) and public administration. Until the 1990s, military promotions in Italy (in the Carabinieri and Army) to colonel or general were often based on bribes equal to peer review research, around €20,000, linked to a recommendation, of course. Hence the lack of prestige attached to such ranks. All things considered, it's no wonder that the Sicilian economy is a disaster. It's rather embarrassing when the first large-scale organ transplant unit in Sicily (ISMETT) is established only in the late 1990s, and then with the help of an American hospital. It makes Sicily seem like an under-developed country. Were it not so ironic, it would be amusing to see the deceptive manner in which officials often disguise their efforts to exploit the status quo by overtly supporting pointless anti-Mafia public awareness campaigns while robbing public monies. Sadly, the European Commission and the central Italian government continue to support many so-called development projects in Sicily, few of which result in little more than untaxed wealth for the projects' managers. Indeed, the phenomenon has spawned an entire industry as politicians and their friends scramble to propose projects with grossly inflated budgets. In the 1980s, a new profession, that of the progettista , was born. The term refers to the project consultant who seeks European Commission funds on organizational behavior robbins and job satisfaction behalf of a town, association or governmental agency (presumably one lacking personnel competent to know how to manage public money efficiently, as though that were an review research esoteric art), and importance of sports essay, then spends these monies, taking a large commission for himself and his cohorts.

To many Sicilians, the progettisti are new mafiosi, or perhaps new robber barons. Considering the vast investments involved, the tangible results are precious few, apart from expensive vacation homes for the project administrators themselves. One can only review research paper, conclude that Sicilian progettisti, Mafia proponents or Sicilian politicians have in some way infiltrated or corrupted elements of the European Commission in Brussels. It's a long way from stealing cattle in the mountains. The Discovery of America.

Our discussion concentrates on the Mafia in business Sicily . It is worth mentioning, however, that outside Italy, the Mafia and its progeny have been the peer research paper, object of horse plan every form of paper fame that modern society carries in cirrhosis paper its sophisticated cinematic arsenal. The first films to depict the Mafia in an appealing light were made not in Italy, but in peer paper the United States, where authors like the late Mario Puzo presented American mafiosi as pseudo-aristocrats. Organizational Behavior Attitudes And Job Satisfaction? It is an image still bolstered by television and cinematic portrayals despite the research, fact that the American Mafia, if indeed it ever conformed very closely to essay, such stereotypes, has been overshadowed in its own country by criminal organizations from South America, the peer review research paper, Far East and Russia. In Italy, films such as I Grimaldi (The Grimaldis) present the glossy cinematic portrayal of the essay on always respect your, homegrown version of the peer paper, Mafia based on the American model, complete with lavish homes, luxury cars and attractive, well-dressed people (its use of the cirrhosis of the liver research paper, name of the ruling dynasty of Monaco implicitly associating mafiosi with royalty). Peer Form? This is an image that contrasts sharply with the reality we see on the evening newscasts - of organizational behavior robbins plump, ugly men with unattractive wives and peer review form, ordinary cars, living underground as latitanti (fugitives) despite their wealth. When Bernardo Provenzano, a Mafia boss, was finally arrested, he was living in a makeshift bunker outside his native Corleone. On the other side of the ocean, several Italian-American cultural organisations decry the persistent cinematic image as nothing less than bigotry, citing the to arms research, (accurate) statistic that fewer than one percent of Italo-Americans are in the Mafia. A few of these organisations, echoing the official position held by the FBI until the 1970s, denied the research paper, very existence of the Mafia until it was mentioned in criminal cases in federal courts in the 1980s. Until then, anti-defamation lobbying garnered some isolated and on always respect your teachers, unexpected results; it was strange, for instance, to hear references to the syndicate in peer review research American telefilms when everybody knew from context that the teleplays' characters were referring to the Mafia, which American mafiosi usually referred to as our thing or our business.

Sicilians laugh at the charming Italo-American myth that the Mafia doesn't exist, but they also enjoy The Sopranos and Goodfellas. Unfortunately, cultural factors have sometimes added to the confusion; to outsiders, New Yorkers Rudolph Giuliani and John Gotti seemed to represent opposite sides of the same ethnic coin, and the negative side of that coin still appeals to some of America's Italian descendants in before essay search of an easily-acquired cultural identity, the so-called guido. Renting The Godfather trilogy at the DVD store is peer review form research paper easier than reading Dante's Divine Comedy . The Freshman and Married to the Mob were successful parodies, while The Untouchables and Goodfellas presented a slightly more accurate, and less varnished, view of the Mafia in America. In Italy, the cultural element creates fewer complexities. Italians recognise that today's mafiosi are drawn from the lowest social stratum, and nobody outside that (rather large) social class would ever aspire to be a mafioso. Collaborating with the Mafia, however, is another story. It is impossible to independence essay, separate the Mafia from today's Sicilian political corruption. Review Research Paper? Indeed, it is essay on always this aspect of review research paper Sicilian life which permits the Mafia's survival. Its adaptability has always distinguished the farewell to arms, Mafia.

Now that heroin smuggling is passé the organisation has infiltrated many parts of the review form paper, legitimate economy. This is more than mere money laundering. Mafia front men (often associates not yet tainted by criminal records) have established everything from supermarkets and shopping malls to cirrhosis of the paper, stores selling computers and cell phones. These businesses - a source of peer form paper revenue in themselves - feed the Mafia. So do betting parlors and bingo salons. Crime and Punishment. The 1980s saw greater international collaboration in before Mafia cases, especially between the peer form paper, Italian and before independence in india, American governments. The former passed a law against research paper, associazione mafiosa (Mafia-type association), whose effects are similar to those of the essay teachers, American RICO Statutes. Unlike Americans, Italians refer to organized crime not for the sake of euphemism but because there are so many independent criminal organizations in Italy (the Mafia in review Sicily, the Comorra in attitudes Naples, etc.). Mafiosi are occasionally (if not routinely) jailed, and sentences are fairly harsh for peer review form research the worse offenders. Some of the captured mafiosi have begun to turn state's evidence, actually breaking the code of silence to unmask their accomplices.

The most famous of these pentiti is importance Tommaso Buscetta. Italy has no death penalty, and leftists want to make life sentences illegal. Peer Review Paper? Despite the laws regarding Mafia association, the burden of legal proof required for conviction is very high. Unfortunately, while it's sometimes easy enough to confiscate a chain of supermarkets or even a clinic owned by mafiosi (yes, they're in health care too), the related matters of bribery and corruption in public life are more difficult to address. Many Sicilians, including judges Giuseppe Falcone and Paolo Borsellino, have literally given their lives in business plan the war against the Mafia.

Some of peer paper Sicily's more prominent politicians would have us believe that the Mafia is nearly extinct. (Perhaps those who promote such a fantasy are themselves involved with it in some way.) Reports of behavior robbins and job its early demise are greatly exaggerated. Though by now somewhat dated, the most authoritative book published in English on peer review form research paper the Sicilian Mafia is the late Claire Sterling's Octopus - The Long Reach of the International Sicilian Mafia (New York and London 1990). Its extensive bibliography provides a wealth of material for anybody interested in reading further on this topic. Our history of the Mafia presents information on its origins.

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essay on peer review form research paper, speciation Every individual alive today, the highest as well as the lowest, is derived in an unbroken line from the first and lowest forms. - August Frederick Lopold Weismann, German biologist/geneticist (1834-1914) From the remotest past which Science can fathom, up to the novelties of yesterday, that in which Progress essentially consists, is the transformation of the homogeneous to importance of sports, the heterogeneous. - Herbert Spencer, English philosopher/psychologist (1820-1903) What is biological evolution? How are theories of microevolution and macroevolution related? What is form research, a species, and what are the different ways it can be defined? What are the of the liver paper, limitations of peer review paper, each definition? How is reproductive isolation important to speciation, and what forms can it take?

Why should natural selection reinforce reproductive isolation? Can species be formed in ways other than geographic isolation? The word evolution does not apply exclusively to biological evolution. Of The? The universe and our solar system have developed out of the explosion of matter that began our known universe. Review Research Paper? Chemical elements have evolved from simpler matter. Life has evolved from before essay, non-life, and peer form complex organisms from simpler forms. Cirrhosis Liver? Languages, religions, and political systems all evolve. Hence, evolution is an appropriate theme for peer research a course on global change. The core aspects of evolution are change and the role of history, in that past events have an influence over what changes occur subsequently.

In biological evolution this might mean that complex organisms arise out of simpler ancestors - though be aware that this is an over-simplification not acceptable to a more advanced discussion of importance of sports essay, evolution. A full discussion of evolution requires a detailed explanation of genetics, because science has given us a good understanding of the genetic basis of evolution. It also requires an investigation of the peer review form paper, differences that characterize species, genera, indeed the entire tree of life, because these are the phenomena that the theory of evolution seeks to explain. We will begin with observed patterns of similarities and differences among species, because this is what Darwin knew about. The genetic basis for evolution only began to and job, be integrated into evolutionary theory in the 1930's and 1940's. We will add genetics into form research, our understanding of to arms research paper, evolution through a discussion activity. Definitions of review form research, Biological Evolution. Changes in the genetic composition of a population with the behavior attitudes satisfaction, passage of each generation.

The gradual change of living things from one form into another over the course of peer form research paper, time, the origin of species and lineages by descent of research paper, living forms from ancestral forms, and the generation of research, diversity Note that the first definition emphasizes genetic change. It commonly is referred to importance of sports essay, as microevolution . The second definition emphasizes the appearance of new, physically distinct life forms that can be grouped with similar appearing life forms in form paper, a taxonomic hierarchy. It commonly is referred to as macroevolution . A full explanation of evolution requires that we link these two levels. Can small, gradual change produce distinct species? How does it occur, and horse business plan how do we decide when species are species? Hopefully you will see the connections by the end of these three lectures. Today we will discuss how species are formed. Review Paper? But to do this, we need to essay, define what we are talking about. Mimicry complexes supplied further evidence against the concept, as organisms of the peer review research, same species can look very different, depending upon of sports where they are reared or their life cycle stage (some insects produce a spring brood that looks like one host plant and a summer brood that looks like another). The morphological species concept was replaced by another viewpoint that puts more emphasis on the biological differences between species.

Biological species concept: This concept states that a species is a group of actually or potentially interbreeding individuals who are reproductively isolated from other such groups. This definition was attractive to biologists and became widely adopted by the 1940's. It suggested a critical test of species-hood: two individuals belong to the same species if their gametes can unite with each other under natural conditions to produce fertile offspring. This concept also emphasized that a species is an evolutionary unit. Members share genes with other members of their species, and not with members of other species. Although this definition clearly is attractive, it has problems.

Can you test it on museum specimens or fossil data? Can it explain the existence of species in peer form research, a line of descent, such as the well-known lineage of fossil horses? Obviously not. In fact, one cannot apply this definition easily, or at all, with many living organisms. What if species do not live in the same place? What about the hybrids that we know occur in zoos? These problems are serious enough that some biologists recently argued for a return to importance, the morphological species concept. So what is the best way to define a species? Most scientists feel that the biological species concept should be kept, but with some qualifications.

It can only be used with living species, and paper cannot always be applied to species that do not live in the same place. The real test applies to species that have the potential to research paper, interbreed. Most importantly, the biological species concept helps us ask how species are formed, because it focuses our attention on the question of how reproductive isolation comes about. Let us first examine types of reproductive isolation, because there are quite a few. This suggests a simple and useful dichotomy, between pre-mating or prezygotic (i.e., pre-zygote formation) reproductive isolating mechanisms, and post-mating or postzygotic isolating mechanisms. Remember that a zygote is the cell formed by the union of two gametes and peer is the basis of a developing individual. Ecological isolation: Species occupy different habitats. Farewell Research? The lion and tiger overlapped in India until 150 years ago, but the research, lion lived in open grassland and the tiger in business plan, forest. Peer Review Form Research Paper? Consequently, the two species did not hybridize in nature (although they sometimes do in zoos). Temporal isolation: Species breed at different times. In North America, five frog species of the genus Rana differ in the time of their peak breeding activity.

Behavioral isolation: Species engage in distinct courtship and mating rituals ( see Figure 1 ). Mechanical isolation: Interbreeding is farewell to arms research, prevented by structural or molecular blockage of the peer research, formation of the of sports essay, zygote. Mechanisms include the inability of the sperm to bind to the egg in animals, or the female reproductive organ of review research, a plant preventing the wrong pollinator from landing. ** All of the above prevent the formation of hybrid zygotes. ** ** Post-zygotic mechanisms are those in which hybrid zygotes fail, develop abnormally, or cannot self-reproduce and establish viable populations in nature. ** So species remain distinct due to reproductive isolation. But how do species form in the first place? An abbreviated illustration of meiosis, by which reproductive cells duplicate to form gametes. This question is behavior attitudes and job satisfaction, critical, because it is form research paper, what produces many species from few, and results in evolutionary trees of relatedness. The most common way for species to split, especially in animal species (we will talk more about the origin of new plant species later), is when the population becomes geographically isolated into two populations. This is referred to as allopatric (geographic) speciation ( see Figure ). Geographic isolation leads to reproductive isolation. Once two populations are reproductively isolated, they are free to follow different evolutionary paths.

They are likely to differentiate for two reasons: Different geographic regions are likely to have different selective pressures. Temperature, rainfall, predators and competitors are likely to differ between two areas 100's or 1,000's of kilometers apart. Thus, over time, the two populations will differentiate. Even if the environments are not very different, the populations may differentiate because different mutations and genetic combinations occur by essay respect your teachers chance in each. Thus, selection will have different raw material to act upon in each population. In short, physical isolation turns a single population into two, which, because of their lack of connectedness, may follow different evolutionary paths. What happens next? The fate of the review research paper, populations depends upon essay respect teachers time and factors related to review research paper, their different environments. If the two populations are soon rejoined, they may not differ very much, and likely will become a single population again. Differentiation also depends upon the strength of selective pressures.

Strong selection can cause rapid change. Given time and selection, the horse business plan, two populations become two species. Peer Form Research? They may, at some later time, spread back into contact. Then we can ask, are these two good biological species? The real test of the biological species concept is when two populations, on the threshold of becoming two species, come back into contact.

They may simply merge. They may be so different that they do not even recognize one another as species. Often, though, species may come into of the research, contact when not yet fully reproductively isolated. In that event, natural selection should reinforce the reproductive barriers. Review Research? Why? Because individuals that waste their reproductive effort -- their gametes -- on individuals with whom they will produce inferior offspring are less likely to pass on their genes to the next generation.

Natural selection should reinforce reproductive isolation. Probably, species that are isolated only by behavior robbins attitudes and job satisfaction post-zygotic barriers will subsequently evolve pre-zygotic barriers. Peer Form Research? Why should that occur? To review: allopatric (geographic) speciation is the differentiation of physically isolated populations to the point that reunion of the two populations does not occur if contact is cirrhosis paper, re- established. If speciation is a gradual process, species may not yet be fully separated. A continuum must exist from species that are in the process of peer research paper, splitting into before, two, to species that are fully formed.

Surely we only expect the latter to behave as good species. We still haven't fully explained the review form research, speciation process. In our next lesson, we will examine the theory of natural selection, which helps to explain how localized populations become adapted to local conditions. By adapting to local conditions and accumulating genetic differences, isolated geographic races start down the essay, path to becoming separate species and creating another pair of branches on the tree of life. But now I want to point out that there are alternative models of species formation, and finally I want to conclude by paper linking the concept of species formation to the hierarchical structure of organizational attitudes satisfaction, life. Alternative Models of review paper, Species Formation -- Hybridization and Polyploidy.

Even if hybrids are unable to undergo sexual reproduction because their chromosomes do not sort out properly in meiosis, they may reproduce vegetatively. The total chromosome number also may double by combining the chromosome sets of of sports, a single species. Of the 260,000 known species of plants, as many as half may have originated in this way. Review Paper? Many commercially important plants are examples of polyploidy (e.g. bread wheat, cotton, tobacco, sugar cane, bananas, potatoes). In India? Polyploidy is an example of sympatric speciation defined as species arising within the same, overlapping geographic range. Conclusion: Species Formation and form paper the Hierarchy of Life. There are two ways to to arms, construct a phylogenetic tree ( see Figure ). We can use a perfect fossil record to trace the sequence from beginning to end, or we can use similarities and differences among living things to reconstruct history, working from the endpoint toward the beginning.

In this course, we will not consider these two methods in detail. I introduce them to make the review research, point that, ultimately, we want to understand how evolution produces not just two species from one but the entire tree of life. This requires that we make the transition from organizational attitudes satisfaction, microevolution to macroevolution. To Darwin, and to modern evolutionary biologists as well, the answer simply is time. Peer Review Form? Given enough time and successive splittings, the before, processes that produce two species from one will result in the entire diversity of life.

In reality, deducing the historic record of branching is review form research paper, very difficult. Data are incomplete, scientists debate the pace of change, and sometimes species separated by many branching steps look more similar to one another than those separated by one or a few branches. Horse Business Plan? Molecular biology offers exciting new opportunities to address these issues, by looking at similarities and differences in review form research paper, DNA sequences. From here we will turn away from the macroevolutionary view and look more closely at how small changes occur and on always respect your teachers accumulate, by the processes of peer form research, natural selection and importance essay genetic change. The definition of a species is debatable. Most scientists adhere either to the morphological species concept (members of a species look alike and can be distinguished from other species by their appearance), or to the biological species concept (a species is a group of actually or potentially interbreeding individuals who are reproductively isolated from other such groups). Peer? Both definitions have their weaknesses. Reproductive isolating mechanisms are either prezygotic or postzygotic. These mechanisms ensure that species remain distinct in nature. Species formation can occur either through allopatric (geographic) speciation or through sympatric speciation.

We can construct phylogenetic trees that show the evolutionary relatedness among living things, though the building of such trees is as yet an imperfect science. Futuyma, D.J. 1986. Evolutionary Biology . Sunderland, Mass: Sinauer Associates, Inc. Wessells, N.K. and J.L. Before Independence In India? Hopson. Peer Review Form Research? 1988. Biology . New York: Random House. Chapter 43. Rosenzweig, M.L. 1995.

Species Diversity in Space and essay on always respect your teachers Time . Cambridge: Cambridge University Press. Copyright Regents of the University of Michigan unless noted otherwise.