Les centres d’appels sont des éléments clés de presque n’importe quelle grande organisation. Le problème de gestion du travail a reçu beaucoup d’attention dans la littérature. Une formulation typique se base sur des mesures de performance sur un horizon infini, et le problème d’affectation d’agents est habituellement résolu en combinant des méthodes d’optimisation et de simulation. Dans cette thèse, nous considérons un problème d’affection d’agents pour des centres d’appels soumis a des contraintes en probabilité. Nous introduisons une formulation qui exige que les contraintes de qualité de service (QoS) soient satisfaites avec une forte probabilité, et définissons une approximation de ce problème par moyenne échantillonnale dans un cadre de compétences multiples. Nous établissons la convergence de la solution du problème approximatif vers celle du problème initial quand la taille de l’échantillon croit. Pour le cas particulier où tous les agents ont toutes les compétences (un seul groupe d’agents), nous concevons trois méthodes d’optimisation basées sur la simulation pour le problème de moyenne échantillonnale. Étant donné un niveau initial de personnel, nous augmentons le nombre d’agents pour les périodes où les contraintes sont violées, et nous diminuons le nombre d’agents pour les périodes telles que les contraintes soient toujours satisfaites après cette réduction. Des expériences numériques sont menées sur plusieurs modèles de centre d’appels à faible occupation, au cours desquelles les algorithmes donnent de bonnes solutions, i.e. la plupart des contraintes en probabilité sont satisfaites, et nous ne pouvons pas réduire le personnel dans une période donnée sont introduire de violation de contraintes. Un avantage de ces algorithmes, par rapport à d’autres méthodes, est la facilité d’implémentation. / Call centers are key components of almost any large organization. The problem of labor management has received a great deal of attention in the literature. A typical formulation of the staffing problem is in terms of infinite-horizon performance measures. The method of combining simulation and optimization is used to solve this staffing problem. In this thesis, we consider a problem of staffing call centers with respect to chance constraints. We introduce chance-constrained formulations of the scheduling problem which requires that the quality of service (QoS) constraints are met with high probability. We define a sample average approximation of this problem in a multiskill setting. We prove the convergence of the optimal solution of the sample-average problem to that of the original problem when the sample size increases. For the special case where we consider the staffing problem and all agents have all skills (a single group of agents), we design three simulation-based optimization methods for the sample problem. Given a starting solution, we increase the staffings in periods where the constraints are violated, and decrease the number of agents in several periods where decrease is acceptable, as much as possible, provided that the constraints are still satisfied. For the call center models in our numerical experiment, these algorithms give good solutions, i.e., most constraints are satisfied, and we cannot decrease any agent in any period to obtain better results. One advantage of these algorithms, compared with other methods, that they are very easy to implement.

<p>Dans ce travail nous abordons deux problèmes non résolus en Probabilité appliquée. Nous les approchons tous deux sous un angle nouveau, en utilisant des outils aussi variés que les chaînes de Markov, les mouvements Browniens, les transformations de Schwarz-Christoffel, les processus de Poisson et la théorie des temps d'arrêts optimaux. <p><p>Problème de la ruine pour N joueurs<p><p>Le problème de la ruine pour $N$ joueurs est un problème célèbre dont la solution pour $N=2$ est connue depuis longtemps. Nous l'abordons premièrement en toute généralité, en le modélisant comme un problème d'absorption pour une chaîne de Markov. Nous obtenons les distributions associées à ce problème et nous décrivons un algorithme (appelé {it folding algorithm}) permettant de diminuer considérablement le nombre d'opérations nécessaires à une résolution complète. Cette étude nous permet de mettre en avant un certain nombres de relations de récurrence satisfaites par les probabilités de ruines associées à chaque état de la chaîne de Markov. Nous étudions ensuite une version asymptotique du problème de la ruine pour 3 joueurs. Nous utilisons les propriétés d'invariance des mouvements Browniens par transformations conformes pour décrire une résolution de ce problème via les transformations de Schwarz-Christoffel. Cette méthode dépasse le cadre strict du problème de la ruine pour 3 joueurs et s'applique à d'autres problèmes de temps d'atteinte d'un bord par un mouvement Brownien. <p><p>Problème de Robbins<p><p>Ce problème s'inscrit dans le cadre de la théorie des temps d'arrêts optimaux. C'est un problème d'analyse séquentielle dans lequel un observateur examine $n$ variables aléatoires indépendantes de manière séquentielle et doit en sélectionner exactement une sans rappel. L'objectif est de déterminer une stratégie qui permette de minimiser le rang moyen de l'observation sélectionnée. <p><p> Nous décrivons un modèle alternatif de ce problème, dans lequel le décideur observe un nombre aléatoire d'arrivées distribuées suivant un processus de Poisson homogène sur un horizon fixe $t$. Nous prouvons l'existence d'une stratégie optimale pour chaque horizon, et nous montrons que la fonction de perte associée à cette stratégie est uniformément continue sur $R$. Nous décrivons une fonction de perte restreinte qui permet d'obtenir une estimation de la valeur asymptotique du problème, et nous obtenons la valeur asymptotique associée à des stratégies spécifiques. Nous obtenons ensuite une équation intégro-diffférentielle sur la fonction de perte associée à la stratégie optimale. Finalement nous étudions les valeurs asymptotiques du problème et nous les comparons à celles du problème en temps discret. Nous concluons cette thèse en décrivant des stratégies spécifiques qui permettent d'obtenir des estimations sur le comportement asymptotique de la fonction de perte. <p><p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The Diploma thesis Organic composition in 20th century abstract Art, Music and Literature aims to explain the gradual process of liberalization of expressive means in Arts, Music and Literature during the 20th century. It describes the picture's emancipation from the dependence on objective reality, particularly V. Kandinsky's way towards abstract expressionism. In Music it traces A. Schonberg's development of the free atonality, and the stream of consciousness technique of J. Joyce in literature. The thesis' second part will be dealing with various manifestations of the organic composition after WWII- action and informal painting in the USA and Europe with its qualitative change. A musical and literal paralel to the principal of organic order will also be briefly introduced on the example of E. Brown's and J. Cage's aleatoric music and the spontaneous writing of J. Kerouac. Selected artistic personalities will be put into socio-cultural context of their time. As a result there comes a complex picture of the organic composition development process, suitable to be used as a source of information for teachers. The didactical part of the thesis will be focused on the possibility of using the given topic in the educational environment.

The aim of this PhD thesis is to analyse the current status of European insolvency law and with the help of both national and European judicial decisions put together an overview of practical obstacles that insolvency courts, debtors, creditors and insolvency trustees across Europe are facing when dealing with cross-border insolvencies. At the very core of this topic stands the European Insolvency Regulation ("EIR") which was adopted in 2015 and is effective within the member states as of June 2017. Since this regulation was put together as a recast of its predecessor, i.e. the original insolvency regulation adopted in 2000 and effective as of 2002, naturally this research is oriented at comparing the two legislative acts and mainly assessing whether or not the recast EIR managed to overcome some of the inconsistencies in the wording of the original EIR, often resulting in conflicting interpretations and a great deal of preliminary rulings filed with the Court of Justice of the EU. Apart from looking into good old instruments of private international law such as the scope, the jurisdiction, the choice of law and the recognition and enforcement rules governed by the EIR, this thesis also focuses on topics that are very bankruptcy-specific and dissimilar to anything we know from other fields of law....

En el presente trabajo, se plantea realizar una investigación con el objetivo de determinar la posible relación entre el Social Media Marketing, es decir los contenidos publicados por las marcas en redes sociales, y el Customer Engagement, que representa el enganche o atracción de los usuarios más participativos y comprometidos con la marca de su preferencia. Asimismo, se plantea comprobar la relación entre la generación de Engagement y el Brand Loyalty hacia la marca, como resultado de la mejora de la imagen hacia la marca y la confianza percibida por parte de los consumidores. Cabe resaltar, a su vez, que se han identificado diversos autores que han desarrollado investigaciones con las variables mencionadas, las cuales han sido utilizadas como referencias para la elaboración del presente trabajo. Sin embargo, se ha procedido a aplicar esta investigación en un contexto diferente, tratándose de un sector en auge como es el sector gaming. Este sector refiere a todas aquellas marcas que participan activamente, como es el caso de aquellas marcas que producen periféricos o dispositivos ligados al consumo de videojuegos, y aquellas empresas que buscan posicionarse en este sector pero que distribuyen productos de otro tipo de categorías. Para finalizar es necesario mencionar la siguiente investigación plantea realizar técnicas cuantitativas, específicamente se realizarán cuestionarios como parte de la investigación de los consumidores denominados como “gamers”. / In the present work, a research is proposed with the aim of determining the possible relationship between Social Media Marketing, that is to say, the contents published by the brands in social networks, and Customer Engagement, which represents the engagement or attraction of the most participative and committed users with the brand of their preference. Likewise, it is proposed to verify the relationship between the generation of Engagement and the Brand Loyalty towards the brand, as a result of the improvement of the image towards the brand and the confidence perceived by the consumers. It should be noted that several authors have developed research with the above-mentioned variables, which have been used as references for the preparation of this paper. However, this research has been applied in a different context, being a growing sector such as the gaming sector. This sector refers to all those brands that actively participate, as is the case of those brands that produce peripherals or devices linked to the consumption of video games, and those companies that seek to position themselves in this sector but that distribute products from other types of categories. To conclude, it is necessary to mention the following investigation proposes to carry out quantitative techniques, specifically questionnaires will be carried out as part of the investigation of consumers known as "gamers". / Trabajo de investigación

The purpose of this study is to explore the literature for textless voice and woodwind instruments. The primary focus concerns the timbral and ensemble possibilities exploited in three twentieth-century works in which the voice is treated as an instrument i.e., without the usual preoccupation with textual meaning. An historical overview of vocal works with obbligato woodwinds and concerted works for textless voice serves as an introductory chapter. The variables of voice and instrument acoustical makeup, vocal vowel formation and instrumental voicings, volume, vibrato, resultant tones, range, and extended techniques (fluttertongue, special vibrato demands, non-vibrato, etc.) are the focus of the performance considerations for this study. Over thirty twentieth-century textless works for voice and at least one woodwind instrument were located. The three, chosen for this study represent different periods in the century, and present contrasting styles and musical merit: Aria (1931) by Jacques Ibert, Three Vocalises (1958) by Ralph Vaughan Williams, and Duos I (1976) by Nancy Chance. A style and performance analysis of these works with pertinent research on the composers is presented. Appendices include an annotated bibliography of selected works for the medium, a written interview with Nancy Chance, and performance notes provided by the composer, concerning Duos I.

The study is an investigation into the pathways of out-of-school youth and their re-entrance into the Education Training and Development (ETD) system or the labour market. In the study the pathways of youth who dropped out of school between grades 1 and 11 are traced as they seek re-entrance to the ETD system, or entrance into the labour market. Particular attention was given to the factors that determine the choices that dropouts make either in re-entering the ETD system or entering the labour market. An analysis of the experiences of the interviewed sample of dropouts is presented. The study employs a qualitative research methodology using interviews to elicit the experiences of dropouts and school managers. The participants (young people and three school principals) were selected through snowballing from a township south of Durban. Individual and focus group interviews were held. The findings provide evidence of the value of investing in education, as suggested by the youth. This is in line with the human capital theory framework that suggests that there are major benefits to investing in education. The study is concluded by suggesting the need for second chance education in South Africa. / Thesis (PhD)--University of Pretoria, 2011. / Education Management and Policy Studies / unrestricted

Martina Rolincová Indebtedness of Czech households and its impact on quality of life Thesis Abstract The thesis "Indebtednesst of Czech households and its impact on quality of life," explores the phenomenon of over-indebtedness and thus, what impacts has this problem on life satisfaction of borrowers and their families. The main goal of this work is to describe these effects and instruments how Czech legislation responds to this negative phenomenon. Part of the work is a qualitative research among borrowers, their families and staff of non-bank credit institutions and agencies of discharge. Based on the analysis of this research and legislative background of this issue finds the author next to insufficient financial literacy also gaps in the legislation in protecting relatives against the consequences of wrong decisions of their family members.

Mnoho inženýrských úloh vede na optimalizační modely s~omezeními ve tvaru obyčejných (ODR) nebo parciálních (PDR) diferenciálních rovnic, přičemž jsou v praxi často některé parametry neurčité. V práci jsou uvažovány tři inženýrské problémy týkající se optimalizace vibrací a optimálního návrhu rozměrů nosníku. Neurčitost je v nich zahrnuta ve formě náhodného zatížení nebo náhodného Youngova modulu. Je zde ukázáno, že dvoustupňové stochastické programování nabízí slibný přístup k řešení úloh daného typu. Odpovídající matematické modely, zahrnující ODR nebo PDR omezení, neurčité parametry a více kritérií, vedou na (vícekriteriální) stochastické nelineární optimalizační modely. Dále je dokázáno, pro jaký typ úloh je nutné použít stochastické programování (EO reformulace), a kdy naopak stačí řešit jednodušší deterministickou úlohu (EV reformulace), což má v praxi význam z hlediska výpočetní náročnosti. Jsou navržena výpočetní schémata zahrnující diskretizační metody pro náhodné proměnné a ODR nebo PDR omezení. Matematické modely odvozené pomocí těchto aproximací jsou implementovány a řešeny v softwaru GAMS. Kvalita řešení je určena na základě intervalových odhadů "optimality gapu" spočtených pomocí metody Monte Carlo. Parametrická analýza vícekriteriálního modelu vede na výpočet "efficient frontier". Jsou studovány možnosti aproximace modelu zahrnujícího pravděpodobnostní členy související se spolehlivostí pomocí smíšeného celočíselného nelineárního programování a reformulace pomocí penalizační funkce. Dále je vzhledem k budoucím možnostem paralelních výpočtů rozsáhlých inženýrských úloh implementován a testován PHA algoritmus. Výsledky ukazují, že lze tento algoritmus použít, i když nejsou splněny matematické podmínky zaručující konvergenci. Na závěr je pro deterministickou verzi jedné z úloh porovnána metoda konečných diferencí s metodou konečných prvků za použití softwarů GAMS a ANSYS se zcela srovnatelnými výsledky.

[pt] Este trabalho propõe a inclusão de restrições probabilísticas como alternativa para inclusão de aversão ao risco no problema de planejamento de longo prazo da geração em sistemas hidrotérmicos, resolvido por programação dinâmica dual estocástica (PDDE). Propõe-se uma abordagem menos restritiva em comparação com métodos alternativos de aversão a risco já avaliados no sistema brasileiro, como a curva de aversão ao risco (CAR) ou a superfície de aversão a risco (SAR). Considera-se uma decomposição de Benders de dois estágios para o subproblema de cada nó da árvore de cenários da PDDE, onde o subproblema de segundo estágio é denominado CCP-SAR. O objetivo é obter uma política operativa que considere explicitamente o risco de não atendimento à demanda vários meses à frente, no subproblema CCP-SAR, com uma modelagem contínua das variáveis aleatórias associadas à energia natural afluente aos reservatórios, segundo uma distribuição normal multivariada. A região viável para a restrição probabilística é aproximada por planos cortantes, construídos a partir da técnica de bisseção e calculando-se os gradientes dessas restrições, usando o código de Genz. Na primeira parte deste trabalho resolve-se de forma iterativa o subproblema CCP-SAR, para um determinado vetor de armazenamentos iniciais para o sistema. Na segunda parte do trabalho constrói-se uma superfície de aversão a risco probabilística, varrendo-se um espectro de valores para o armazenamento inicial. / [en] This paper proposes the inclusion of chance constrained programming as an alternative to include risk aversion in the long-term power generation planning problem of hydrothermal systems, solved by stochastic dual dynamic programming (SDDP). It is proposed a less restrictive approach as compared to traditional methods of risk aversion that have been used in the Brazilian system, such as risk aversion curve (CAR) or risk aversion surface (SAR). A two-stage Benders decomposition subproblem is considered for each SDDP scenario, where the second stage subproblem is labeled CCP-SAR. The objective is to yield an operational policy that explicitly considers the risk of load curtailment several months ahead, while considering in the CCP-SAR subproblem a continuous multivariate normal distribution for the random variables related to energy inflows to the reservoirs. The feasible region for this chance constrained subproblem is outer approximated by linear cuts, using the bisection method which gradients were calculated using Genz s code. The first part of this dissertation solves the multi-stage deterministic CCP-SAR problem by an iterative procedure, for a given initial vector storage for the system. The second part presents the probabilistic risk aversion surface, for a range of values of initial storage.