Zugl.: Vallendar, WHU - Otto Beisheim School of Management, Diss., 2009.

Diss. Wirtschaftswiss. St. Gallen, 2000 ; Nr. 2479. / Literaturverz.

Thesis (Ph.D.)--University of Delaware, 2010. / Principal faculty advisor: James M. Jones, Dept. of Black American Studies. Includes bibliographical references.

Universiẗat, Diss., 1997--Konstanz.

Video streaming has become, and is expected to remain, the dominant type of traffic over the Internet. With this high demand for multimedia streaming, there is always a question on how to provide acceptable and fair Quality of Experience (QoE) for consumers of the over-the-top video services, despite the best-effort nature of the Internet and the limited network resources, shared by concurrent users. MPEG-DASH, as one of the most widely used standards of HTTP-based adaptive streaming, uses a client-side rate adaptation algorithms; which is known to suffer from two practical challenges: in one hand, clients use fixed heuristics that have been fine-tuned according to strict assumptions about deployment environments which limit its ability to generalize across network conditions. On the other hand, the absence of collaboration among DASH clients leads to unfair bandwidth allocation, and typically ends up in an unbalanced equilibrium point. We believe that augmenting a server-side rate adaptation significantly improves the fairness of network bandwidth allocation among concurrent users. We have formulated the problem as a Decentralized Partially Observable Markov Decision Process (Dec-POMDP) model, and used RL to train two neural networks to find an optimal solution to the proposed Dec-POMDP problem in a distributed way. We showed that our proposed client-server collaboration outperforms the state-of-the-art schemes in terms of QoE-efficiency, QoE-fairness, and social welfare by as much as 16%, 21%, and 24% respectively.

Magister Commercii (Industrial Psychology) - MCom(IPS) / After the 1994 elections South Africa had to undergo drastic changes for it to become a more just society to address past injustices experienced by various ethnic groups. Issues such as equality and social justice have frequently appeared on top of various organisations’ agenda. The South African Government realised legislation was of paramount importance to guide organisations in promoting justice in the workplace. These changes in the legislation have had several impacts on organisations operating in South Africa, namely turnover, recruitment and retention of employees in the workplace. Attempting to preside over the promotion of social justice and eliminate inequalities experienced in the workplace, Government realised it had to intercede, not only to prevent additional discrimination, but also to promote the employment and advancement of individuals who were disadvantaged by previous policies. The Government therefore in 1998 implemented the Employment Equity Act to fulfil a constitutional mandate to prohibit discrimination in the workplace and encourage Affirmative Action (AA) measures. Describing and explaining the role of fairness as a concern in the workplace, the term organisational justice was coined. Individuals will base fairness judgements by taking into consideration the actual decision or the procedures used to reach a decision. Organisational justice can be divided into distributive, procedural and interactional justice. Organisations in South Africa face the challenge of finding ways to implement EE strategies to gain competitive advantages without creating negative employee attitudes; attention will focus on how to overcome the barriers that hinder the successful implementation of EE practices and procedures.

La communauté de Calcul Haute Performance est constamment confrontée à de nouveaux défis en raison de la demande toujours croissante de la puissance de traitement provenant dapplications scientifiques diverses. Les systèmes parallèles et distribués sont la clé pour accélérer lexécution de ces applications, et atteindre les défis associés car de nombreux processus peuvent être exécutés simultanément. Ces systèmes sont partagés par de nombreux utilisateurs qui soumettent des tâches sur de longues périodes au fil du temps et qui attendent un traitement équitable par lordonnanceur. Le travail effectué dans cette thèse se situe dans ce contexte: analyser et développer des algorithmes équitables et efficaces pour la gestion des ressources informatiques partagés entre plusieurs utilisateurs. Nous analysons les scénarios avec de nombreux soumissions issues de plusieurs utilisateurs. Ces soumissions contiennent un ou plusieurs processus et lensemble des soumissions sont organisées dans des campagnes successives. Dans ce que nous appelons le modèle dordonnancement des campagnes les processus dune campagne ne commencent pas avant que tous les processus de la campagne précédente soient terminés. Chaque utilisateur est intéressé à minimiser la somme des temps dexécution de ses campagnes. Cela est motivé par le comportement de lutilisateur tandis que lexécution dune campagne peut être réglé par les résultats de la campagne précédente. Dans la première partie de ce travail, nous définissons un modèle théorique pour lordonnancement des campagnes sous des hypothèses restrictives et nous montrons que, dans le cas général, il est NP-difficile. Pour le cas mono-utilisateur, nous montrons que lalgorithme dapproximation pour le problème (classique) dordonnancement de processus parallèles fournit également le même rapport dapproximation pour lordonnancement des campagnes. Pour le cas général avec plusieurs utilisateurs, nous établissons un critère déquité inspiré par une situation idéalisée de partage des ressources. Ensuite, nous proposons un algorithme dordonnancement appelé FairCamp qui impose des dates limite pour les campagnes pour assurer léquité entre les utilisateurs entre les campagnes successives. La deuxième partie de ce travail explore un modèle dordonnancement de campagnes plus relâché et réaliste, avec des caractéristiques dynamiques. Pour gérer ce cadre, nous proposons un nouveau algorithme appelé OStrich dont le principe est de maintenir un ordonnancement partagé virtuel dans lequel le même nombre de processeurs est assigné à chaque utilisateur. Les temps dachèvement dans lordonnancement virtuel déterminent lordre dexécution sur le processeurs physiques. Ensuite, les campagnes sont entrelacées de manière équitable. Pour des travaux indépendants séquentiels, nous montrons que OStrich garantit le stretch dune campagne en étant proportionnel à la taille de la campagne et le nombre total dutilisateurs. Le stretch est utilisé pour mesurer le ralentissement par rapport au temps quil prendrait dans un système dédié. Enfin, la troisième partie de ce travail étend les capacités dOStrich pour gérer des tâches parallèles rigides. Cette nouvelle version exécute les campagnes utilisant une approche gourmande et se sert aussi dun mécanisme de redimensionnement basé sur les événements pour mettre à jour lordonnancement virtuel selon le ratio dutilisation du système. / The High Performance Computing community is constantly facing new challenges due to the ever growing demand for processing power from scientific applications that represent diverse areas of human knowledge. Parallel and distributed systems are the key to speed up the execution of these applications as many jobs can be executed concurrently. These systems are shared by many users who submit their jobs over time and expect a fair treatment by the scheduler. The work done in this thesis lies in this context: to analyze and develop fair and efficient algorithms for managing computing resources shared among multiple users. We analyze scenarios with many submissions issued from multiple users over time. These submissions contain several jobs and the set of submissions are organized in successive campaigns. In what we define as the Campaign Scheduling model, the jobs of a campaign do not start until all the jobs from the previous campaign are completed. Each user is interested in minimizing the flow times of their own campaigns. This is motivated by the user submission behavior whereas the execution of a new campaign can be tuned by the results of the previous campaign. In the first part of this work, we define a theoretical model for Campaign Scheduling under restrictive assumptions and we show that, in the general case, it is NP-hard. For the single-user case, we show that an approximation scheduling algorithm for the (classic) parallel job scheduling problem also delivers the same approximation ratio for the Campaign Scheduling problem. For the general case with multiple users, we establish a fairness criteria inspired by time sharing. Then, we propose a scheduling algorithm called FairCamp which uses campaign deadlines to achieve fairness among users between consecutive campaigns. The second part of this work explores a more relaxed and realistic Campaign Scheduling model, provided with dynamic features. To handle this setting, we propose a new algorithm called OStrich whose principle is to maintain a virtual time-sharing schedule in which the same amount of processors is assigned to each user. The completion times in the virtual schedule determine the execution order on the physical processors. Then, the campaigns are interleaved in a fair way. For independent sequential jobs, we show that OStrich guarantees the stretch of a campaign to be proportional to campaigns size and to the total number of users. The stretch is used for measuring by what factor a workload is slowed down relatively to the time it takes to be executed on an unloaded system. Finally, the third part of this work extends the capabilities of OStrich to handle parallel jobs. This new version executes campaigns using a greedy approach and uses an event-based resizing mechanism to shape the virtual time-sharing schedule according to the system utilization ratio.

Equity theory has long been used to predict individuals' responses to equity and inequity. Tests of these predictions have been inconsistent, particularly for inequitable conditions of low inputs and high outcomes, or overreward. Based on empirical evidence pointing to the powerful effects of moods on cognitive tasks, this study incorporates mood into equity theory's propositions, with the expectation that considering mood will enhance equity theory's predictive power. Specifically, as Wyer and Carlston's (1979) "feelings-as-information" hypothesis suggests, subjects who receive favorable outcomes may use their positive outcome-based mood in judging the fairness of the situation. Cognitive research suggests that positive mood reduces the accuracy of judgments, which would explain the inconsistencies in equity perceptions. However, Schwarz and Clore (1983) discovered that the effect of mood on judgments may be eliminated if the mood can be attributed to a logical external source. Two studies were conducted using similar procedures with different overrewards and external sources. In both studies, overrewarded subjects rated the fairness of being overrewarded and the fairness of the procedures used to allocate the reward. These ratings were analyzed to assess the effects that subjects' inputs, outcomes, and procedures had on their perceptions of fairness. Two groups were given the opportunity to attribute their moods to a source other than the reward. It was hypothesized that mood effects on fairness judgments would be eliminated when subjects were able to attribute their mood to its correct source (i.e., undeserved reward) or to an incorrect but logical source (i.e., music or cheerful surroundings). Specifically, the elimination of the effect of positive mood should serve to increase accuracy in judgments of fairness. The hypothesis that subjects who were treated with fair procedures would view their outcome as more distributively fair was supported in both studies. In Study 1, the hypotheses regarding changes in judgment accuracy as a function of external attribution of positive mood were not supported. The results of Study 2, which used a different overreward and transient source, revealed that external attribution of positive mood had a significant effect on subjects' fairness ratings. / Master of Science

Zugl.: Luzern, Univ., Habil.-Schr., 2006

In education a new dimension started after the 1994 elections by implementing new legislation to ensure fair conduct towards all. New labour legislation was promulgated to contribute to fairness in South Africa. This legislation was also implemented in the South African education system to ensure that educators are treated fairly. The Employment of Educators Act (EEA), the Labour Relations Act (LBA), the Equity Act and the South African Schools Act (SASA) were promulgated to protect both the rights of the employer and the educator in education. The purpose of this research was to determine the perception of educators in the Oudtshoorn district regarding fairness in the workplace; how educators understand and experience their right to equality in the workplace; what their perception is regarding disciplinary action in the workplace, and to what extent educators have the basic concept and principle of labour law to prevent frustration in the workplace and ineffective service delivery, and to prevent the pursuit of incorrect procedures. It is crucial that the educator knows his or her rights as an employee, and what his or her obligations towards the employer are. This research was done on the basis of the literature study and the analysis of legislation that is applicable to educators. A qualitative enquiry into educators’ perceptions of fairness in the workplace was conducted amongst participants from the Oudtshoorn district, which included schools from different socio-economic and cultural backgrounds. This case study was based on interviews with school managers, educators on post level 1 and with union representatives in the Oudtshoorn district. Questionnaires were structured to obtain the participants’ view and perception on fairness in the workplace and to determine their knowledge regarding the law and their rights in education with regards to labour law. The participants didn’t receive guidance because it could have influenced their answers. The data derived from the participants made it possible to compile certain recommendations and conclusions. From the empirical research it was evident that educators in the Oudtshoorn district had but a vague knowledge of their rights as educators and of legislation. Shortcomings that were apparent from this study were addressed, recommendations were made, and possible future research on related topics was indicated. / MEd (Education Law), North-West University, Potchefstroom Campus, 2014