Spelling suggestions: "subject:"consensus"" "subject:"census""
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Certification formelle de la correction d'algorithmes distribués avec erreurs de transmission / Formal verification of distributed algorithms with transition failuresDebrat, Henri 06 December 2013 (has links)
La propension des systèmes informatiques à subir des défaillances matérielles est à l'origine d'une recherche abondante afin de concevoir des systèmes dits tolérants aux pannes. Le procédé couramment retenu consiste à procéder à des réplications, donnant alors naissance à ce que l'on nomme un système distribué. La question se pose alors de savoir si l'on peut garantir que les multiples copies sont cohérentes entre elles. Ainsi, la recherche d'un accord devient-elle un problème à résoudre, à portée paradigmatique : le Consensus. Or, la complexité des algorithmes de Consensus rend la tache ardue : il n'est donc pas rare que l'on commette des erreurs lors de leur conception. De là découle l'idée, développée depuis plus de trente ans, de recourir à des procédés de vérification mécanique des algorithmes et de leurs preuves de correction. Ces procédés prennent place parmi ce que l'on désigne usuellement comme étant des méthodes formelles. C'est à la croisée des recherches en algorithmique distribuée et en méthodes formelles que se situent nos travaux. Plus spécifiquement, il s'agit de faire usage d'un logiciel de certification formelle, Isabelle/HOL, afin de garantir l'exactitude des preuves de correction d'algorithmes de Consensus exprimés dans un cadre formel uniforme du nom de Heard-Of, proposé en 2009 par Charron-Bost et Schiper. Nous montrons que, du fait de leur expression dans un même cadre formel, et du fait de leur proximité, suivant les cas, soit de conception (nombre de rondes, recours à des mécanismes de vote, ...) soit de forme syntaxique, soit d'hypothèses de fonctionnement (synchronisme partiel, ...), ces algorithmes présentent des preuves dont une part conséquente d?arguments sont communs. Cela permet de copier certains d'entre eux d'une preuve à l'autre, afin de réduire l'effort de certification : ces arguments peuvent alors être automatiquement évalués par la machine pour chacun d'entre eux, l'utilisateur n'ayant à intervenir que là où celle-ci est en peine, c'est-à-dire lorsque les différences algorithmiques induisent qu'il faille réviser les détails de l'argumentation. L'exposé que nous faisons de la certification que nous avons effectuée pour six algorithmes distribués dédiés à la résolution du problème du Consensus illustre cette démarche. Par conséquent, nous présentons d'abord les portions communes des démonstrations, puis détaillons ce qui est propre à chacune, l'objectif n'étant pas de permettre une lecture linéaire de chaque démonstration mais de mettre en évidence notre proposition / Computer systems fail. Whatever the reason of these failures, it has been a widespread approach to try and increase the faults-tolerance of a computer system through its replication. The resulting system is said to be a distributed one, in which replicas have to be kept consistent with each others. Hence, reaching agreement, and Consensus in particular, becomes the problem to solve - indeed, the paradigm. Solving Consensus (under various assumptions) is a hard task : algorithms designed on this purpose are subtle and proving their being correct is error-prone - whenever they are, which occasionally appears not to be the case. For more that thirty years, researchers interested in what is called Formal Methods have been working on mechanizing the verification process, in order to increase confidence in the correctness of (distributed) algorithms. The work we present here is at the intersection of distributed algorithms and formal methods. We use the Isabelle/HOL software to certify the correctness proof of various Consensus algorithms expressed in a uniform framework based on the Heard-Of Model, introduced by Charron-Bost and Schiper in 2009. Expressed in a common model, these algorithms, which, depending on the case, share some common mecanisms (number of steps, intermediate votes, ...), some elements of syntax, or types of assumptions (partial synchronism...), can be proved using some common arguments. As a consequence, the certification effort can be reduced by copying some intermediate lemmas from one proof to another and let the computer automatically parse them until some manual adaptation is required. This lead to the idea of certifying the correctness of multiple algorithms all together, instead of proving them one after the other, as one would do on paper in a traditional way. The effort of translation in the formal language of the proof assistant is then possibly reduced. Of course, each proof will also contain specific arguments, which will have to be isolated and translated into the software. Here, we illustrate this proposition through the presentation of formal certificates of correctness for six Consensus algorithms. As a consequence, on should not expect to find here a comprehensive linear presentation of each proof : we first show the arguments shared by multiple proofs, followed by those which are specific to each o them
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Comprehensiveness versus pragmatism: Consensus at the Japanese-Dutch interface.Keizer, Arjan B., Benders, J.G.J.M., Noorderhaven, N.G. 07 June 2009 (has links)
No / By comparing the views of managers working at the interface of two consensus-oriented societies, Japan and the Netherlands, we show important differences between the consensus decision-making processes as seen by Japanese and Dutch managers. These differences relate to how complete the agreement of opinion should be in order to speak of consensus, with the Japanese managers demanding a more complete consensus than the Dutch. The processes and conditions that Japanese and Dutch managers see as leading to consensus also differ. Japanese consensus is based on a more ordered, sequential process than Dutch consensus. Our respondents differed deeply regarding the role of the hierarchy in their own and the others consensus processes, with both Japanese and Dutch managers seeing their own consensus process as less hierarchical. Our findings show that the concept of consensus is interpreted quite differently by Japanese and Dutch managers. This is an important warning for companies operating at the interface of these two societies. More in general our research illustrates the usefulness for international management research of detailed comparative studies focusing not on stark contrasts but on more subtle differences between management practices.
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Globalization and Small Countries - Unique Challenges, Universal SolutionsPetkovska, Katerina January 2014 (has links)
This work focuses on globalization, more closely on the economic aspects of this process. Small countries, especially developing ones are in the spotlight, as they face unique challenges that have been addressed by the international community for decades at least. The success rate of the intervention is very questionable and leaves room for improvement, which may be a platform to elevate millions out of poverty, solve crippling problems, provide access to technology and improve the global economic system. The uniting hypothesis is that that small developing nations are functioning in a hostile environment when it comes to trade, intellectual property protection and debt, which makes it extremely difficult for them to globalize competitively. Economic history, trade and technology are the main filters of this research. Conventional economic theory like market fundamentalism, and international trade theories will be discussed. A holistic literature review, will try to depict the many sides of the argument. The data used will be from the World Competitiveness Report, World Bank's World Development Indicators, other World Bank data, apropriatiate statistical offices. A case study is implemented to conclude the thesis and in this case to evaluate the hypothesis as only partly true, since small...
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Det specialpedagogiska uppdraget ur olika perspektiv : En intervjuundersökning bland rektorer, lärare och elevhälsopersonal / The special pedagogical mission from diffrent perspectives. : An interwiew survey conducted by principals, teachers and student health professionalsJohansson, Barbro January 2018 (has links)
The purpose of this study has been to gain knowledge of the different perspectives on the special educational assignment, which form the basis of the mission, by examining perceptions, expectations and frameworks for the special education assignment of principals, educators and student health professionals. The study is done with a phenomenographic research effort with interview as a method, where the perceptions of the interviewees are central. Two classical pedagogical perspectives visualize the field of special education in the study, the relational and the compensatory perspective. The result of the study presents perceptions of the special pedagogical assignment from a relational perspective, the special education assignment from a compensatory perspective and another category of perceptions of the special pedagogue in an expert role. In Sweden there are two different special educational professional roles, the special educator and special teacher, and a confusion is at hand. Different pedagogical perspectives, approaches can also confuse, such as the responsibility for a student's needs, as well as different expectations of the special education assignment, and everyone involved different interpretations in, on and outside the school around a student. The result of the study shows that some in school activities see the special educator as a person who will patch and fix when the regular teaching is insufficient and some have expectations of the special educator as both adviser, qualified dialogue partner and expert. / Syftet med studien har varit att vinna kunskap om de olika perspektiv som finns på det specialpedagogiska uppdraget, vilka utgör uppdragets förutsättningar, detta genom att undersöka uppfattningar, förväntningar och ramar för det specialpedagogiska uppdraget hos rektorer, pedagoger och elevhälsopersonal. Studien är gjord med en fenomenografisk forskningsansats med intervju som metod, där uppfattningar hos de intervjuade är det centrala. Två klassiska pedagogiska perspektiv synliggör kunskapsområdet specialpedagogik i studien, det relationella- och det kompensatoriska perspektivet. Studiens resultat redovisar uppfattningar på det specialpedagogiska uppdraget ur ett relationellt perspektiv, det specialpedagogiska uppdraget ur ett kompensatoriskt perspektiv samt ytterligare en kategori med uppfattningar om specialpedagogen i en expertroll. I Sverige finns två olika specialpedagogiska yrkesroller, specialpedagogens och speciallärarens och en sammanblandning ligger nära till hands. Olika pedagogiska perspektiv, synsätt kan också förvirra, som till exempel var ansvaret kring en elevs behov ska ligga, samt olika förväntningar på det specialpedagogiska uppdraget och alla inblandades olika tolkningar i, på och utanför skolan kring en elev. Resultatet i studien visar att vissa i skolverksamheten ser specialpedagogen som den som ska lappa och laga när den ordinarie undervisningen inte räcker till och vissa har förväntningar på specialpedagogen som både rådgivare, kvalificerad samtalspartner och expert.
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Perceptions Of Neighborhood Problems: Agreement Between Police and Citizens and Impact on Citizen Attitudes Toward PoliceWinesburg, Melissa 20 April 2011 (has links)
No description available.
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Ethnicity and Politics of Exclusion in Nigeria : Employing Rawls'Theory of Justice in Plural SocietiesOzoeze, Victor Anthony January 2005 (has links)
<p>With an estimated 250 ethnic groups, Nigeria, no doubt, has been grappling with the problem of pluralism of ethnic nationalities. It is not news in Nigeria that extreme ethnic consciousness of its citizens has led to the victimization of one ethnic group by another. This victimization has come in the form of exclusions in the distribution of both wealth and power in the country.</p><p>Amidst all the exclusions, the unity of the country has been ironically regarded as sacrosanct, and should not be negotiated. It is often said that fate brought all the ethnic nationalities in order to form one great country. I subscribe to this belief that fate brought us together for the above purpose, especially now that several countries around the world are merging in one way or the other to form a formidable force to reckon with both politically and economically. Hence, “(ethnic integration) is the integration of capabilities. It develops the capabilities of the workforce… it offers opportunities for better synergy of skills”. However, it would be ethically unhealthy for the unity of the country not to be compromised under the present dispensation, which has been compromising in turn the basic moral principle of social justice. There cannot be any moral basis for the continued existence of a country like Nigeria, which as it were, has thrown equality of all citizens to the dogs.</p><p>Should the country remain united, it must do so by imbibing the culture of regarding all citizens, as well as, all ethnic nationalities as equal, and none should have more privileges than the others. Therefore, how can a plural society like Nigeria remain united as one indivisible country?</p><p>Rawls has offered some solutions to the problem of stability engendered by the pluralism of ethnic groups in Nigeria. His idea of ‘overlapping consensus of reasonable comprehensive doctrines’ in his Political Liberalism is capable of bringing back the country to the state of stability. There will be stability, if all forms of exclusion seize to exist in the Nigerian polity.</p>
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Ethnicity and Politics of Exclusion in Nigeria : Employing Rawls'Theory of Justice in Plural SocietiesOzoeze, Victor Anthony January 2005 (has links)
With an estimated 250 ethnic groups, Nigeria, no doubt, has been grappling with the problem of pluralism of ethnic nationalities. It is not news in Nigeria that extreme ethnic consciousness of its citizens has led to the victimization of one ethnic group by another. This victimization has come in the form of exclusions in the distribution of both wealth and power in the country. Amidst all the exclusions, the unity of the country has been ironically regarded as sacrosanct, and should not be negotiated. It is often said that fate brought all the ethnic nationalities in order to form one great country. I subscribe to this belief that fate brought us together for the above purpose, especially now that several countries around the world are merging in one way or the other to form a formidable force to reckon with both politically and economically. Hence, “(ethnic integration) is the integration of capabilities. It develops the capabilities of the workforce… it offers opportunities for better synergy of skills”. However, it would be ethically unhealthy for the unity of the country not to be compromised under the present dispensation, which has been compromising in turn the basic moral principle of social justice. There cannot be any moral basis for the continued existence of a country like Nigeria, which as it were, has thrown equality of all citizens to the dogs. Should the country remain united, it must do so by imbibing the culture of regarding all citizens, as well as, all ethnic nationalities as equal, and none should have more privileges than the others. Therefore, how can a plural society like Nigeria remain united as one indivisible country? Rawls has offered some solutions to the problem of stability engendered by the pluralism of ethnic groups in Nigeria. His idea of ‘overlapping consensus of reasonable comprehensive doctrines’ in his Political Liberalism is capable of bringing back the country to the state of stability. There will be stability, if all forms of exclusion seize to exist in the Nigerian polity.
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