Suchergebnisse

I: Optimization Theory -- A method for linearly constrained minimization problems -- On a class of nonconvex optimization problems -- Lower semicontinuity of marginal functions -- A new approach to symmetric quasiconvex conjugacy -- Generalized convexity, functional hulls and applications to conjugate duality in optimization -- Conjugation Operators -- Global minimization of a difference of two convex functions -- Closures and neighbourhoods induced by tangential approximations -- II: Control Theory -- On the principal of "Internal Modelling" in linear control theory -- On optimal observability of Lipschitz systems -- III: Mathematical Economics -- Convergence of ?-fields and applications to mathematical economics -- Optimal growth policies for resource-dependent open economies -- A characterization of the proportional income tax -- Duality in the theory of social choice -- Nonlinear models of business cycle theory -- Existence of economic equilibrium: new results and open problems -- IV: Game Theory -- Silent duel with accuracies less than 1 -- Extensions and modifications of the ?-value for cooperative games -- Stochastic games with state independent transitions and separable rewards -- Core stability and duality of effectivity functions -- A procedure for computing the f-nucleolus of a cooperative game -- V: Graph Theory -- An O(nlogn)-algorithm for the minimum cost flow problem in trees -- A construction for strongly greedy ordered sets -- Plane constructions for graphs, networks and maps measurements of planarity -- On two problems related to the traveling salesman problem on Halin graphs -- VI: Fixed Point Theory -- Piecewise linear approximation of solution manifolds for nonlinear systems of equations -- Periodic orbits of semiflows — local indices and sections -- VII: Statistics and Measure Theoretic Concepts -- Monotone decision rules for the two-armed bandit -- On the existence of monotone optimal decision rules -- Integral representation of functionals on arbitrary sets of functions -- Invariance properties of the Banach algebra of Darboux integrable functions -- Construction of locally extremal measure extensions -- Generalized fox integral equations solved by functional equations -- VIII: Applications -- An algorithm for linear multiple-choice Knapsack problem -- New algorithms and results of numerical experiments for solution of mathematical programming and optimal control problems -- Methods of determining systems of time-table arranging with predetermined area -- Some remarks on the relation between mathematics, computer science, and medicine.

19 April 2022 A Correction to this paper has been published: https://doi.org/10.1007/s42979-022-01141-w ; [Abstract] Computing the product of the (binary) adjacency matrix of a large graph with a real-valued vector is an important operation that lies at the heart of various graph analysis tasks, such as computing PageRank. In this paper, we show that some well-known webgraph and social graph compression formats are computation-friendly, in the sense that they allow boosting the computation. We focus on the compressed representations of (a) Boldi and Vigna and (b) Hernández and Navarro, and show that the product computation can be conducted in time proportional to the compressed graph size. Our experimental results show speedups of at least 2 on graphs that were compressed at least 5 times with respect to the original. ; We thank Cecilia Hernández for providing us with her software extracting the bicliques, and a helpful description in how to run it. This research has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie [grant agreement No 690941], namely while the first author was visiting the University of Chile, and while the second author was affiliated with the University of Helsinki and visiting the University of A Coruña. The first author was funded by Fundação para a Ciência e a Tecnologia (FCT) [grant number UIDB/50021/2020 and PTDC/CCI-BIO/29676/2017]; the second author was funded by the Academy of Finland [Grant number 268324], Fondecyt [Grant number 1171058] and NSERC [Grant number RGPIN-07185-2020]; the third author was funded by JSPS KAKENHI [grant numbers JP21K17701 and JP21H05847]; the fourth author was funded by AEI and Ministerio de Ciencia e Innovación (PGE and FEDER) [grant number PID2019-105221RB-C41] and Xunta de Galicia (co-funded with FEDER) [Grant numbers ED431C 2021/53 and ED431G 2019/01]; and the fifth author was funded by ANID – Millennium Science Initiative Program – Code ICN17_002 ; Xunta de Galicia; ED431C 2021/53 ...

BackgroundExisting association between mental disorders and suicidality is mostly based on cross- sectional studies, using clinical samples.
Objective and methodsWe examined the patterns of association between mental disorders and subsequent suicide in a representative sample of the Canadian household population. This is a retrospective cohort study that used data from the Canadian Community Health Survey 2002 linked to the Death Database 2000-2011 and the Hospitalization Database 1999/2000-2012/2013) (N=27,000). Mental disorders (past-year major depressive episodes (MDE), bipolar disorders (BPD), anxiety disorders (AD), and substance-dependent (SD)) were diagnosed in the survey data using the Composite International Diagnostic Interview. Subsequent suicide events (deaths/hospitalizations for suicide attempts) were identified using ICD-10-CA codes. Time-to-event data were analyzed using competing-risk regression models, adjusting for age, sex, marital status, and educational attainment. Due to the violation of the proportional hazard assumption, the models were stratified into two strata. Sampling weights were used to ensure representation of the target population.
ResultsOf 27,000 respondents, mental disorders were diagnosed in 15.0% respondents and 0.4% had suicide events. Each mental disorder was significantly associated with an increased risk of suicide. The strength of association between mental disorder and suicide weakened over-time for MDE, SD, but not for BPD and AD. For example, using the time-to-event cut-off 4-year, the hazard ratio (HR) for MDE was 6.02 (95% CI=2.65,13.68) in the first 4-year, whereas, it was 2.03 (95% CI=0.91,4.53) after 4-year. The HRs of suicide for BPD were 16.95 (95% CI=6.88,41.75) and 15.81 (95% CI=5.89,42.45) before and after 4-year.
Conclusions/ImplicationsFindings reflect improvement of suicide-risk over-time for people with MDE and SA and the persisting risk for people with BPD and AD. Our findings underscore the importance of early management of mental disorders for effective suicide prevention, and requirement of longer-term follow-up for people with BPD and AD.

IntroductionAgeing populations place considerable burden on healthcare systems. Innovative methods to implement and evaluate new care models to reduce unwarranted hospital presentations, are needed.
Objectives and ApproachTo use linked Electronic Medical Record (EMR) data to evaluate a pilot community-based model of care to reduce hospital presentations in a cohort of patients at-risk of hospital representations following an acute admission. Patients admitted to a metropolitan hospital with a non-surgical condition andidentified as being at-risk of readmission using a state-wide risk algorithm, were eligible to receive a 30-day care navigation model of care. The intervention group were matched to similar eligible patients, who received usual care using propensity score matching. Linked data were obtained from the EMR based Data Warehouse to provide information on subsequent readmissions and community-based health service contacts. Readmission rates were compared at 30, 60, and 90-days post-discharge using Cox Proportional Hazards Regression, adjusted for confounders and weighted by the propensity score. Descriptive analyses were used to compare demographics and healthcare utilisations.
ResultsData from 412,971 potentially eligible patients were extracted. Sixty-five received the intervention of which 63 were matched to 280 controls (aged 51-91 years, 54% female, 63% lived alone). At 30-days post-discharge (during intervention delivery) an 80% reduction in readmission rate in the intervention group was observed (Hazard Ratio [HR] 0.20; 95%Confidence Interval (CI) [0.01, 4.20]). At 60-days (HR 0.48; 95%CI [0.03, 8.05]) and 90-days (HR 0.83; 95%CI [0.06, 11.36]), readmission rate reductions decreased to 52% and 17% respectively. In the intervention group, 68.9% received an out-patient appointment compared to 40% of controls (P<0.001) and 7.7% received allied health compared to none of the controls (p=0.003) within 90-days post-discharge.
Conclusion/ImplicationsResults have informed hospital-wide service implementation thereby demonstrating the value of linked EMR data and advanced statistical methods in the evaluation of real-world healthcare.

Although many climate research experiments are providing valuable data, long-term measurements are not always affordable. In the last decades, several facilities have secured long-term experiments, but few studies have incorporated spatial and scale effects. Most of them have been implemented in experimental agricultural fields but none for ecological studies. Scale effects can be assessed using remote sensing images from space or airborne platforms. Unmanned aerial vehicles (UAVs) are contributing to an increased spatial resolution, as well as becoming the intermediate scale between ground measurements and satellite/airborne image data. In this paper we assess the applicability of UAV-borne multispectral images to provide complementary experimental data collected at point scale (field sampling) in a long-term rain manipulation experiment located at the Kiskun Long-Term Socio-Ecological Research (LTSER) site named ExDRain to assess the effects on grassland vegetation. Two multispectral sensors were compared at different scales, the Parrot Sequoia camera on board a UAV and the portable Cropscan spectroradiometer. The NDVI values were used to assess the effect of plastic roofs and a proportional reduction effect was found for Sequoia-derived NDVI values. Acceptable and significant positive relationships were found between both sensors at different scales, being stronger at Cropscan measurement scale. Differences found at plot scale might be due to heterogeneous responses to treatments. Spatial variability analysis pointed out a more homogeneous response for plots submitted to severe and moderate drought. More investigation is needed to address the possible effect of species abundance on NDVI at plot scale contributing to a more consistent representation of ground measurements. The feasibility of carrying out systematic UAV flights coincident or close to ground campaigns will certainly reveal the consistency of the observed spatial patterns in the long run. ; This research was funded by the European Union's Horizon 2020 Research and Innovation Program under grant agreement No. 654359 (eLTER Horizon 2020 project). Gy. K-D. was supported by the National Research, Development and Innovation Fund (NRDI Fund) of Hungary (Nos. K112576, K129068) ; We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI) ; Peer reviewed

This study focuses on how political institutions--electoral systems and legislative rules, and coalition agreement policy pledges--affect consensus in national parliaments. Two theoretical propositions are established and tested empirically. Proposition 1 contends that consensus will be higher under proportional systems of representation (PR) than under its majoritarian alternatives. Proposition 2 contends that under coalition government, legislative consensus should be higher on legislative motions lacking governing coalition commitment. Proposition 1 is tested with new legislative vote data from New Zealand and Belgium covering those countries' institutional transformations to PR. To test Proposition 2, I focus on periods of coalition government in New Zealand and Belgium after their transition to PR, and in Britain during the Conservative-Liberal Democrat coalition government. The analysis indicates that New Zealand's electoral system change in the mid-1990s caused a significant increase in consensus, and after reform bills assigned to a select committee chaired by an opposition MP were more likely to result in a bipartisan vote outcome, consistent with Proposition 1. Belgium's institutional transformation from 1893 to 1921 coincided with a decrease in consensus on budgetary legislation. This development suggests that PR will not have a consensus inducing effect in the near-term if the adoption of PR coincides with democratization, though the adoption of PR sets the stage for consensus building over time. Support for Proposition 2 is mixed. In post-reform New Zealand I find that confidence and supply agreements hold those parties to the agreement together when the corresponding bill comes up for a final vote. However, governing coalition commitments are not found to increase consensus in New Zealand. During the Catholic-Liberal coalition government in Belgium from 1921-23, the opposition Socialist Party was significantly more likely to oppose the government on votes approving bills prioritized in the government's post-election declaratory speech, consistent with Proposition 2. During the Conservative-Liberal Democrat coalition in Britain, government policy commitments have a limited effect on vote outcomes. This finding confirms that the effect of coalition agreements on legislative voting in an otherwise majoritarian parliamentary system will be limited.

Networks have broad applicability to real-world systems, due to their ability to model and represent complex relationships. The discovery and forecasting of insightful patterns from networks are at the core of analytical intelligence in government, industry, and science. Discoveries and forecasts, especially from large-scale networks commonly available in the big-data era, strongly rely on fast and efficient network algorithms. Algorithms for dealing with large-scale networks are the first topic of research we focus on in this thesis. We design, theoretically analyze and implement efficient algorithms and parallel algorithms, rigorously proving their worst-case time and space complexities. Our main contributions in this area are novel, parallel algorithms to detect k-clique communities, special network groups which are widely used to understand complex phenomena. The proposed algorithms have a space complexity which is the square root of that of the current state-of-the-art. Time complexity achieved is optimal, since it is inversely proportional to the number of processing units available. Extensive experiments were conducted to confirm the efficiency of the proposed algorithms, even in comparison to the state-of-the-art. We experimentally measured a linear speedup, substantiating the optimal performances attained. The second focus of this thesis is the application of networks to discover insights from real-world systems. We introduce novel methodologies to capture cross correlations in evolving networks. We instantiate these methodologies to study the Internet, one of the most, if not the most, pervasive modern technological system. We investigate the dynamics of connectivity among Internet companies, those which interconnect to ensure global Internet access. We then combine connectivity dynamics with historical worldwide stock markets data, and produce graphical representations to visually identify high correlations. We find that geographically close Internet companies offering similar services are driven by common economic factors. We also provide evidence on the existence and nature of hidden factors governing the dynamics of Internet connectivity. Finally, we propose network models to effectively study the Internet Domain Name System (DNS) traffic, and leverage these models to obtain rankings of Internet domains as well as to identify malicious activities.

Цель. Целью представленного исследования является выявление структурированных представлений о возможности управления развитием, в частности государственного управления, на основе сравнительного междисциплинарного анализа концепций и прикладных исследований, представляющих различные социальные науки. Предмет исследования. Концептуализация проблемы управления развитием, в частности государственного управления развитием как специфически организованной деятельности. Методология. Сравнительное качественное исследование текстов научных статей, монографий и официальных документов в рамках структурированной выборки (n = 200), охватывающей публикации, появившиеся или переизданные в 1990-2014 гг., основанной на цитируемости исследований, с равной представленностью основных социальных дисциплин (социальная философия, социология, политология, экономика, государственное управление, менеджмент, психология и педагогика), с пропорциональной цитируемости на русском языке представленностью русскоязычных, англоязычных, франкоязычных и германоязычных исследований, включая переведённые на русский язык. Научная новизна. Выявлены основные парадигмы исследовательского и управленческого дискурса, относящегося к проблеме управленческого воздействия на развитие, ключевые проблемные области, связанные с государственным воздействием на развитие. Осуществлена оценка релевантности бытующих в исследовательской литературе подходов с точки зрения перспектив исследования государственного управления развитием. Результаты и область применения. Результатом исследования является структурирование представлений о развитии и об управлении развитием в современной исследовательской литературе, оценка этих представлений применительно к задачам государственного управления развитием. Финансирование. Исследование выполнено в рамках государственного задания 2015 г. Российской академии народного хозяйства и государственной службы при Президенте Российской Федерации. ; Purpose. The purpose of the given research is to identify the structured perceptions of the possibility of development management, in particular public management, on the basis of a comparative interdisciplinary analysis of concepts and applied research representing different social sciences. Research subject. Conceptualization of development management problem, in particular public development management as a specifically organized activity. Methodology. Comparative qualitative research of texts of scientific articles, monographs and official documents in the frames of a structured sample (n = 200), covering those published or republished in 1990-2014, based on the research citation ratio with equal representation of the principal social sciences (social philosophy, sociology, political science, economics, public administration, management, psychology and pedagogics), with the proportional to citation ratio in Russian representation of the Russian-speaking, English-speaking, French-speaking and German-speaking studies, including the translated into Russian. Scientific novelty. Basic paradigms of research and managerial discourse relating to the problem of administrative impact on development, key problem areas referred to the administrative impact on development are revealed. The relevance of prevailing in the research literature approaches are assessed from the point of view of public development management research perspectives. Results and scope. The result of the research is the structuring of the concepts of development and development management in the modern research literature, the assessment of these perceptions with regard to the problems of public development management. Financing. The study was performed with financial support of 2015 state order assigned to the Russian Presidential Academy of National Economy and Public Administration.

This work is organized in three (3) chapters. the first chapter, « Electoral Institutions and Political Polarization: An Experiment on Approval Voting in Benin » coauthored with J-F Laslier, K.Van Der Straten and L. Wantchekon, focus on the institutions 's goal in the division of societies. The main idea is that political institutions can shape political preferences and influence the formation of groups within societies. Some system such Simple plurality and runoff majoritarian voting systems tend to force voters to "choose sides," potentially exacerbating political, social, ethnic, or religious divisions. Voting rules that allow voters to simultaneously select several candidates should, in theory, avoid these drawbacks, and might thus lead to less polarized political outcomes. This chapter provides experimental evidence in support of this insight. Our data originates from an experiment on Approval Voting that took place during the 2011 presidential election in Benin, a democratic, multi-ethnic country in western Africa, with a political landscape characterized by a strong social and political north-south divide. In contrast to the official runoff rule used in Benin for this presidential election, we proposed Approval Voting to voters, whereby they can vote simultaneously for several candidates. We find that this electoral institution leads to an increase in the overall support for more consensual candidates. We also find that, under Approval Voting, like under Proportional Representation systems, ethnic voting does not disappear, and might even increase. The second chapter continue in the logic of voting motivation by doing some laboratory experiment about electoral clientelism. We focus on the vote buying and electoral promises. We wanted to show the impact on electoral clientelism on the election outcome in one way and in the second way, see if there is a link between modernization and clientelism. We did experiment in two different places (Burkina Faso and France) show that the impact of electoral clientelism is more relevant in Africa countries than in developed countries. The third chapter investigates on tax compliance in Africa by using data from about 29 African countries. The goal is to analyze the citizens's behaviors when they have to contribute to public funding by paying tax. We want to know which factors may motivate people have a compliance attitude with tax. The main contribution of this research is the effect of country population and the existence of natural resources. We found that citizens living in countries with natural resources are less willing to pay taxes than citizens living in countries without natural resources. Also, we showed that the population matters. Indeed, in the most populated countries, fraud is higher than less popular countries. We then establish for each group of countries the factors for which they should act to have a tax compliance of their citizens. This can help countries to have a great public finance and become more independent from foreign aid. ; Le travail de thèse s'articule autour de trois chapitres.Le premier chapitre « Electoral Institutions and Political Polarization: An Experiment on Approval Voting in Benin » s'intéresse au rôle des institutions politiques dans la division des sociétés africaines. L'idée principale étant que les institutions politiques pourraient influencer la formation des groupes à l'intérieur des sociétés. Certains systèmes de vote (pluralité, système majoritaire) par leur règle tendent à forcer les électeurs à choisir un camp et pourraient potentiellement conduire à des divisions sociales, ethniques ou religieuses. Les autres règles de vote qui permettent aux électeurs de voter plusieurs candidats à la fois, devraient en théorie éviter ces inconvénients, et ainsi aboutir à une moins grande polarisation politique. Ce chapitre fournit des preuves expérimentales de cette théorie. Nos données proviennent d'une expérience sur le vote d'approbation qui a eu lieu lors de l'élection présidentielle de 2011 au Bénin, un pays démocratique d'Afrique occidentale, multi-ethnique avec un paysage politique caractérisé par une forte fracture nord-sud au niveau sociale et politique. En parallèle au vote officiel (scrutin majoritaire), nous avons proposé le vote par approbation aux électeurs, dont règle leur permet de voter pour plusieurs candidats à la fois. Les résultats montrent que ce système de vote augmente le score de plusieurs candidats consensuels. Nous avons également trouvé que le vote ethnique ne disparait pas et pourrait même augmenter. Dans le chapitre 2 « L'impact du clientélisme électoral: Analyse d'une expérience de laboratoire », nous nous intéressons au clientélisme, son lien avec la modernisation et son impact sur les résultats des élections. Nous avons effectués des expériences de laboratoires dans deux endroits différents (France et Burkina Faso). Les résultats obtenus montrent un effet significatif des campagnes d'achat de vote et de promesses électorales sur le score des candidats dans les deux pays. Mais les campagnes clientélistes sont plus efficaces en Afrique car ils permettent l'élection du candidat clientéliste. Le troisième et dernier chapitre « Quels sont les facteurs qui influencent le consentement à l'impôt en Afrique du Sud Sahara : Une analyse empirique avec des données d'enquêtes d'opinion», fournit une analyse des facteurs déterminant le consentement à payer la taxe des citoyens en Afrique du sud Sahara. En utilisant les données de 29 pays, nous avons montré que la qualité des services publiques, le milieu de résidence, le niveau d'éducation, la confiance aux institutions, la transparence du système fiscal sont des facteurs important dans les décisions des citoyens de consentir à payer la taxe. Nous avions également montré que la présence de ressources naturelle dans un pays, ainsi que le nombre d'habitant dans un pays jouent un rôle dans le consentement à payer la taxes des citoyens. Aussi l'importance accordé aux facteurs déterminant est différent selon la particularité des pays (peuplé ou pas, possédant ou pas des ressources naturelles).

While much of the obvious has been covered in how
the ascension of Republican Speaker Mike Johnson to that post will
affect Louisiana politics, one under-the-radar aspect is how it can strengthen
the state's hand in the current legal tussle over congressional reapportionment.

Last
year, Louisiana, which has a black voting age population of just under a
third, enacted a plan that created one majority-minority district out of six.
Special interests sued, claiming that the Voting Rights Act, despite its explicit
statement that population proportions didn't have to be translated into proportions
of districts, required the state to have two M/M districts.

In a related Alabama case, the U.S. Supreme Court
elevated racial proportion to a preferred status among reapportionment criteria,
which include such things incumbent protection, continuity of representation, and
keeping communities of interest together. Using that as a precedent, an Eastern
District of Louisiana judge firstly threw out the enacted maps and secondly ordered
new ones be drawn.

The decisions were appealed to the Fifth Circuit,
which hasn't ruled on the former but placed a stay on the latter, saying the
former needed resolution first. The Supreme
Court this month backed the stay, using the Louisiana case as a potential vehicle
that gives the Court a chance to set parameters to its Alabama ruling.
Practically speaking, if the former ruling stands, then the Legislature could
deal with the latter next year during the regular session or in a special session
preceding it without judicial involvement.

Assuming the legal wrangling ends in time for the
change to occur next year, whatever the state's majoritarian branches do can
set an important precedent. The Alabama ruling instructed that preference
should be given to proportional use of race to ensure that roughly as many districts
proportional to a discrete minority group's proportion in the population should
exist to give that group a opportunity to elect a chosen candidate, but didn't
mandate that the proportional output should be constructed utilizing only M/M districts.

Thus, it left the door open for "opportunity
districts," or those where the minority population is sufficiently proportionally
large enough to elect a chosen candidate without being a majority, to be utilized
in this kind of mapping, subject to other reapportionment criteria. A subsequent
Alabama attempt that created one M/M and one district with about 40 percent black
population was found inadequate to meet the new criterion.

Louisiana might have the chance to define this
further, if it must come to that. In contrast to the Alabama case, creating two
rather than one M/M district does much greater violence to other
reapportionment criteria, so there would be more leeway to creating an opportunity
district instead. In fact, one bill offered during the 2022 First Extraordinary
Session of the Legislature, called for reapportionment purposes, SB 22 by Democrat
state Sen. Greg Tarver, did
precisely this in making the Fifth District – which in two M/M plans was made
narrowly the second M/M district – a bare majority white district with 43
percent black population.

The case for accepting this arrangement became
stronger with Johnson's ascending to the speakership, referring particularly to
incumbency protection. With Johnson now the most powerful and important official
in the House, it becomes more imperative to maintain a district in which he can
get elected.

Almost every
of over a dozen bills filed in sessions in 2022 to create two M/M districts made
for convoluted plans with these districts at 53 and 52 or 52 and 51 percent
black population and, as compared to the enacted plan
which largely mirrored existing boundaries, considerably altered Johnson's District
4 by chopping off its four southern-most parishes and instead pushing it to gobble
up six parishes to the east and part of Ouachita now in District 5. Tarver's
plan did worse, removing more southern parishes and spreading further east,
circling around Ouachita. Even so, Johnson's district is nearly a third populated
with blacks.

If the GOP legislative majority could swap some
things around with CD 5 – for example, some of St. Landry parish for all of
Grant – and work on CD 5's borders with other districts, this could push CD 5
above 40 percent black while adhering more closely to CD 4's pre-2022
boundaries and better protect Johnson. This would give the judiciary an interesting
test case as to just how much preference to give race when other traditional
factors loom large.

It may not come to this, but if it does, Johnson's
unexpected promotion may cause equally unanticipated permutations to Louisiana's
congressional maps.

My doctoral dissertation begins with this puzzle: why do large, moderate parties sometimes select leaders who seem to help improve their parties' electoral performances, but other times choose unpopular leaders with more extreme policy positions, in expense of votes? I argue that leadership selection is dependent on both the electoral institution that a party finds itself in and the intra-party dynamics that constrain the party. Due to a high degree of seat-vote elasticity that is characteristic of majoritarian systems, replacing unpopular leaders is a feasible strategy for opposition parties in these systems to increase their seat shares. In contrast, in proportional systems, due to low seat-vote elasticity, on average opposition parties that replace their leaders suffer from vote loss. My model of party leadership selection shows that since party members can provide valuable election campaign effort, they can coerce those who select the party leader (the selectorate) into choosing their preferred leader. When selectorate members are moderate, extreme leaders may emerge if non-selectorate members credibly threaten to withhold campaign effort. The more that the extreme non-selectorate members value issue advocacy over the party's electoral welfare, the more extreme the chosen party leader is. Two original datasets on 12 parliamentary democracies of the Organisation for Economic Co-Operation and Development (OECD), one comprised of the dates of party leadership tenure, and the other on leadership election results, highlight my research question's empirical relevance. These data reveal that on average, new opposition party leaders in single-member district (SMD) systems increase their parties' vote share, but the reverse occurs in multi-member district (MMD) systems. Through field research in the Netherlands, Sweden, and the United Kingdom, I interviewed 72 members of parliament (MPs), 7 former party leaders and party leadership candidates, and 18 senior party officers. These interviews serve to support my model's predictions. My dissertation offers an explanation for why parties sometimes seem to injure themselves in the electoral arena by choosing unpopular leaders. It underscores the importance of electoral systems in understanding the dynamics of intra-party politics and the feasibility of different electoral strategies. In addition, intra-party policy conflict influences election outcomes. Moreover, it highlights how, paradoxically, large parties that prioritize their parties' electoral welfare sometimes sacrifice voter representation in order to mobilize party activists.

In one decade Serbia applied almost all of the most widely spread types of electoral systems. Only two electoral cycles for the central representative body were held on the same electoral model. The consequences of electoral legislation on the party system, on the functioning of the parliament and government, were not in line with the parties' expectations, while conflicts between parties in the past decade centered around the electoral system reform. Not one electoral system managed to achieve more than two of the functions that it is expected to: simplicity, participation, aggregation and effectiveness, representation and legitimacy. All electoral reforms were under the strong influence of party self-interests. The attention is now focused on the need for a thorough reform of all elements of electoral legislation, and, along with that, only on the registering of voters, the threshold and on testing the public to establish whether it would accept some of the different kinds of combined majority-proportional model. The author presents his proposals on how to make voter rolls, points to the problems that lowering the threshold could have on the fragmentation of the party system and presents his proposals on how to minimize the potential of the small parties for blackmail; he warns of the potential consequences of introducing a trench electoral model. ; Srbija je u jednoj deceniji primenila gotovo sve najrasprostranjenije varijante izbornih sistema. Samo dva izborna ciklusa za centralno predstavničko telo održana su po istom izbornom sistemu. Posledice izbornog prava po stranački sistem, funkcionisanje parlamenta i vlade nisu bile u skladu sa očekivanjima stranaka, a reforme izbornog sistema bile su okosnica stranačkih konflikata u poslednjoj deceniji. Nijedan izborni sistem nije ispunio više od dve funkcije od onih koje se od njega očekuju jednostavnost, participaciju, agregaciju i efektivnost, reprezentaciju i legitimnost. Sve izborne reforme bile su pod snažnim pritiskom stranačkih interesa. Sada se, pored potrebe za celovitom reformom svih elemenata izbornog prava, pažnja fokusira samo na evidenciju birača, visinu izbornog praga i testiranje javnosti za prihvatanje neke varijante kombinovanog većinsko-proporcionalnog modela. Autor iznosi predloge za izradu evidencije birača; ukazuje na probleme koje po fragmentaciju stranačkog sistema može imati smanjivanje izbornog praga i iznosi predloge za smanjivanje "ucenjivačkog" potencijala malih stranaka; upozorava na posledice koje može proizvesti uvođenje rovovskog izbornog modela.

Computing with Words, although directly issued from the fuzzy set theory that is now more than 40 years old, is still a widely open research domain. Indeed, one of the dreams of the human beings for a very long time is to create really smart machines. The big passion for this research axis has gone down since the failure of Artificial Intelligence (AI) in the seventies or eighties, notably shown by Hubert Dreyfus' book published in 1972 and entitled What Computers Can't Do, and we now know that the robot as an "exact copy of the human being" won't be happening in a hurry. But, to help humans in their decision making and to simulate their reasoning selectively in some specific and well-defined contexts, is a field that has proven its feasibility and efficiency, and has thus aroused again the interest. The fuzzy set theory then the CW with its various representations of linguistic data, has widely contributed to relaunch this part of AI.In this report, we see how the CW can get involved in this field at different levels. In a practical point of view, many applications had and still can have the benefit of linguistic approaches. Let us cite for the record — and to cite only what we personally tackled — colorimetrics, performing arts and autonomic computing fields into which we have experimented and obtained satisfactory results already.In a theoretical point of view, we consider two axes:– the one that consists in formalizing (to generalize and so, to reuse) new concepts from the introduction of linguistic approaches in applications (for instance the formalization of the LCP-nets), i.e. the axis that feeds on applications,– and the one that consists in setting up existing theoretical concepts better (for instance, to imagine a generalized modus ponens, implications, t-norms, t-conorms, etc. dedicated to linguistic 2-tuples) or to imagine new ones (for instance, to imagine a unification of several linguistic models via a vectorial representation), i.e. the axis that feeds applications.So we show the articulation between theory and practice around the linguistic approaches for the modeling and reasoning under uncertainty, one and the other feeding on each other.From the perceptual computing point of view, we have shown that it can benefit from the four following axes that remain objectives at least partially:– the setting of end-to-end linguistic processes,– the use of various representation models — such as the fuzzy subsets, the linguistic 2-tuplesfrom Herrera & Martínez, proportional 2-tuples from Wang & Hao or linguistic degrees from Truck & Akdag — that allow us to catch the nuances and the results of computation using linguistic definition domains whose cardinality is bounded and close to the user perception,– the setting of linguistic tools to go beyond the well-known fuzzy inference, see for example the LCP-nets with their way to deal with conditional preferences, and– the integration of these tools inside knowledge elicitation processes and the handling of these processes to compose them in order to permit more complex reasoning processes, such as the joint inference in the case of collaborative decision-making. ; Le contexte général de mes travaux de recherche se situe dans le domaine de la représentation, modélisation puis combinaison des connaissances en milieu imprécis et vague, en particulier dans la théorie des sous-ensembles flous, d'une part, et dans la théorie des multi-ensembles, d'autre part. Dans ce contexte, nous nous attachons à concevoir des modèles ou outils linguistiques pour palier les problèmes d'imprécision. Notre travail s'est d'abord fondé sur la modulation, préservant la simplicité d'un espace de variables linguistiques de cardinalité assez faible mais sur lequel un large éventail de nuances peut être appliqué. Puis nous avons utilisé ces modèles et outils dans des contextes où l'expression de nuances est très importante, comme le *perceptual computing* dans le domaine de la classification des couleurs ou encore le jeu théâtral, et, plus récemment, pour la capture des intentions des programmeurs pour établir des politiques de contrôle et d'adaptation dynamique des architectures logicielles selon l'approche du calcul auto-régulé (*autonomic computing*).

Computing with Words, although directly issued from the fuzzy set theory that is now more than 40 years old, is still a widely open research domain. Indeed, one of the dreams of the human beings for a very long time is to create really smart machines. The big passion for this research axis has gone down since the failure of Artificial Intelligence (AI) in the seventies or eighties, notably shown by Hubert Dreyfus' book published in 1972 and entitled What Computers Can't Do, and we now know that the robot as an "exact copy of the human being" won't be happening in a hurry. But, to help humans in their decision making and to simulate their reasoning selectively in some specific and well-defined contexts, is a field that has proven its feasibility and efficiency, and has thus aroused again the interest. The fuzzy set theory then the CW with its various representations of linguistic data, has widely contributed to relaunch this part of AI.In this report, we see how the CW can get involved in this field at different levels. In a practical point of view, many applications had and still can have the benefit of linguistic approaches. Let us cite for the record — and to cite only what we personally tackled — colorimetrics, performing arts and autonomic computing fields into which we have experimented and obtained satisfactory results already.In a theoretical point of view, we consider two axes:– the one that consists in formalizing (to generalize and so, to reuse) new concepts from the introduction of linguistic approaches in applications (for instance the formalization of the LCP-nets), i.e. the axis that feeds on applications,– and the one that consists in setting up existing theoretical concepts better (for instance, to imagine a generalized modus ponens, implications, t-norms, t-conorms, etc. dedicated to linguistic 2-tuples) or to imagine new ones (for instance, to imagine a unification of several linguistic models via a vectorial representation), i.e. the axis that feeds applications.So we show the articulation between theory and practice around the linguistic approaches for the modeling and reasoning under uncertainty, one and the other feeding on each other.From the perceptual computing point of view, we have shown that it can benefit from the four following axes that remain objectives at least partially:– the setting of end-to-end linguistic processes,– the use of various representation models — such as the fuzzy subsets, the linguistic 2-tuplesfrom Herrera & Martínez, proportional 2-tuples from Wang & Hao or linguistic degrees from Truck & Akdag — that allow us to catch the nuances and the results of computation using linguistic definition domains whose cardinality is bounded and close to the user perception,– the setting of linguistic tools to go beyond the well-known fuzzy inference, see for example the LCP-nets with their way to deal with conditional preferences, and– the integration of these tools inside knowledge elicitation processes and the handling of these processes to compose them in order to permit more complex reasoning processes, such as the joint inference in the case of collaborative decision-making. ; Le contexte général de mes travaux de recherche se situe dans le domaine de la représentation, modélisation puis combinaison des connaissances en milieu imprécis et vague, en particulier dans la théorie des sous-ensembles flous, d'une part, et dans la théorie des multi-ensembles, d'autre part. Dans ce contexte, nous nous attachons à concevoir des modèles ou outils linguistiques pour palier les problèmes d'imprécision. Notre travail s'est d'abord fondé sur la modulation, préservant la simplicité d'un espace de variables linguistiques de cardinalité assez faible mais sur lequel un large éventail de nuances peut être appliqué. Puis nous avons utilisé ces modèles et outils dans des contextes où l'expression de nuances est très importante, comme le *perceptual computing* dans le domaine de la classification des couleurs ou encore le jeu théâtral, et, plus récemment, pour la capture des intentions des programmeurs pour établir des politiques de contrôle et d'adaptation dynamique des architectures logicielles selon l'approche du calcul auto-régulé (*autonomic computing*).

Computing with Words, although directly issued from the fuzzy set theory that is now more than 40 years old, is still a widely open research domain. Indeed, one of the dreams of the human beings for a very long time is to create really smart machines. The big passion for this research axis has gone down since the failure of Artificial Intelligence (AI) in the seventies or eighties, notably shown by Hubert Dreyfus' book published in 1972 and entitled What Computers Can't Do, and we now know that the robot as an "exact copy of the human being" won't be happening in a hurry. But, to help humans in their decision making and to simulate their reasoning selectively in some specific and well-defined contexts, is a field that has proven its feasibility and efficiency, and has thus aroused again the interest. The fuzzy set theory then the CW with its various representations of linguistic data, has widely contributed to relaunch this part of AI.In this report, we see how the CW can get involved in this field at different levels. In a practical point of view, many applications had and still can have the benefit of linguistic approaches. Let us cite for the record — and to cite only what we personally tackled — colorimetrics, performing arts and autonomic computing fields into which we have experimented and obtained satisfactory results already.In a theoretical point of view, we consider two axes:– the one that consists in formalizing (to generalize and so, to reuse) new concepts from the introduction of linguistic approaches in applications (for instance the formalization of the LCP-nets), i.e. the axis that feeds on applications,– and the one that consists in setting up existing theoretical concepts better (for instance, to imagine a generalized modus ponens, implications, t-norms, t-conorms, etc. dedicated to linguistic 2-tuples) or to imagine new ones (for instance, to imagine a unification of several linguistic models via a vectorial representation), i.e. the axis that feeds applications.So we show the articulation between theory and practice around the linguistic approaches for the modeling and reasoning under uncertainty, one and the other feeding on each other.From the perceptual computing point of view, we have shown that it can benefit from the four following axes that remain objectives at least partially:– the setting of end-to-end linguistic processes,– the use of various representation models — such as the fuzzy subsets, the linguistic 2-tuplesfrom Herrera & Martínez, proportional 2-tuples from Wang & Hao or linguistic degrees from Truck & Akdag — that allow us to catch the nuances and the results of computation using linguistic definition domains whose cardinality is bounded and close to the user perception,– the setting of linguistic tools to go beyond the well-known fuzzy inference, see for example the LCP-nets with their way to deal with conditional preferences, and– the integration of these tools inside knowledge elicitation processes and the handling of these processes to compose them in order to permit more complex reasoning processes, such as the joint inference in the case of collaborative decision-making. ; Le contexte général de mes travaux de recherche se situe dans le domaine de la représentation, modélisation puis combinaison des connaissances en milieu imprécis et vague, en particulier dans la théorie des sous-ensembles flous, d'une part, et dans la théorie des multi-ensembles, d'autre part. Dans ce contexte, nous nous attachons à concevoir des modèles ou outils linguistiques pour palier les problèmes d'imprécision. Notre travail s'est d'abord fondé sur la modulation, préservant la simplicité d'un espace de variables linguistiques de cardinalité assez faible mais sur lequel un large éventail de nuances peut être appliqué. Puis nous avons utilisé ces modèles et outils dans des contextes où l'expression de nuances est très importante, comme le *perceptual computing* dans le domaine de la classification des couleurs ou encore le jeu théâtral, et, plus récemment, pour la capture des intentions des programmeurs pour établir des politiques de contrôle et d'adaptation dynamique des architectures logicielles selon l'approche du calcul auto-régulé (*autonomic computing*).