Cognitive radio (CR) is a novel wireless communication approach that may alleviate the looming spectrum-shortage crisis. Orthogonal frequency division multiplexing (OFDM) is an attractive modulation candidate for CR systems. In this thesis, we study resource allocation (RA) for OFDM-based CR systems using both aggressive and protective sharing. In aggressive sharing, cognitive radio users (CRUs) can share both non-active and active primary user (PU) bands. We develop a model that describes aggressive sharing, and formulate a corresponding multidimensional knapsack problem (MDKP). Low-complexity suboptimal RA algorithms are proposed for both single and multiple CRU systems. A simplified model is proposed which provides a faster suboptimal solution. Simulation results show that the proposed suboptimal solutions are close to optimal, and that aggressive sharing of the whole band can provide a substantial performance improvement over protective sharing, which makes use of only the non-active PU bands. Although aggressive sharing generally yields a higher spectrum-utilization efficiency than protective sharing, aggressive sharing may not be feasible in some situations. In such cases, sharing only non-active PU bands is more appropriate. When there are no fairness or quality of service (QoS) considerations among CRUs, both theoretical analysis and simulation results show that plain equal power allocation (PEPA) yields similar performance as optimal power allocation in a multiuser OFDM-based CR system. We propose a low-complexity discrete bit PEPA algorithm. To improve spectrum-utilization efficiency, while considering the time-varying nature of the available spectrum as well as the fading characteristics of wireless communication channels and providing QoS provisioning and fairness among users, this thesis introduces the following novel algorithms: (1) a distributed RA algorithm that provides both fairness and efficient spectrum usage for ad hoc systems; (2) a RA algorithm for non-real-time (NRT) services that maintains average user rates proportionally on the downlink of multiuser OFDM-based CR systems; and (3) cross-layer RA algorithms for the downlink of multiuser OFDM-based CR systems for both real-time (RT) services and mixed (RT and NRT) services. Simulation results show that the proposed algorithms provide satisfactory QoS to all supported services and perform better than existing algorithms designed for multiuser OFDM systems.

La prise de conscience générale de l'importance de vérifier plus scrupuleusement les programmes a engendré une croissance considérable des efforts de vérification formelle de programme durant cette dernière décennie. Néanmoins, le code qu'exécute l'ordinateur, ou code exécutable, n'est pas le code écrit par le développeur, ou code source. La vérification formelle de compilateurs est donc un complément indispensable à la vérification de code source.L'une des tâches les plus complexes de compilation est l'allocation de registres. C'est lors de celle-ci que le compilateur décide de la façon dont les variables du programme sont stockées en mémoire durant son exécution. La mémoire comporte deux types de conteneurs : les registres, zones d'accès rapide, présents en nombre limité, et la pile, de capacité supposée suffisamment importante pour héberger toutes les variables d'un programme, mais à laquelle l'accès est bien plus lent. Le but de l'allocation de registres est de tirer au mieux parti de la rapidité des registres, car une allocation de registres de bonne qualité peut conduire à une amélioration significative du temps d'exécution du programme.Le modèle le plus connu de l'allocation de registres repose sur la coloration de graphe d'interférence-affinité. Dans cette thèse, l'objectif est double : d'une part vérifier formellement des algorithmes connus d'allocation de registres par coloration de graphe, et d'autre part définir de nouveaux algorithmes optimisants pour cette étape de compilation. Nous montrons tout d'abord que l'assistant à la preuve Coq est adéquat à la formalisation d'algorithmes d'allocation de registres par coloration de graphes. Nous procédons ainsi à la vérification formelle en Coq d'un des algorithmes les plus classiques d'allocation de registres par coloration de graphes, l'Iterated Register Coalescing (IRC), et d'une généralisation de celui-ci permettant à un utilisateur peu familier du système Coq d'implanter facilement sa propre variante de cet algorithme au seul prix d'une éventuelle perte d'efficacité algorithmique. Ces formalisations nécessitent des réflexions autour de la formalisation des graphes d'interférence-affinité, de la traduction sous forme purement fonctionnelle d'algorithmes impératifs et de l'efficacité algorithmique, la terminaison et la correction de cette version fonctionnelle. Notre implantation formellement vérifiée de l'IRC a été intégrée à un prototype du compilateur CompCert.Nous avons ensuite étudié deux représentations intermédiaires de programmes, dont la forme SSA, et exploité leurs propriétés pour proposer de nouvelles approches de résolution optimale de la fusion, l'une des optimisations opéréeslors de l'allocation de registres dont l'impact est le plus fort sur la qualité du code compilé. Ces approches montrent que des critères de fusion tenant compte de paramètres globaux du graphe d'interférence-affinité, tels que sa largeur d'arbre, ouvrent la voie vers de nouvelles méthodes de résolution potentiellement plus performantes.

La juste valeur maintient un lien théorique fort avec l'allocation des ressources étant donné qu'elle permet une vision financière plus collée à la réalité économique que le coût historique notamment pour les instruments financiers. La transparence envers la réalité économique est la déclinaison comptable de la condition d'information parfaite formulée par Pareto dans une allocation des ressources qui serait alors pareto-optimale. L'allocation optimale des ressources étant le but ultime de tout système économique, notre travail de recherche examine le lien entre juste valeur et allocation efficace des ressources. Notre travail teste l'effet de la juste valeur sur l'allocation des ressources en deux points. En tenant compte des variations de valeur des instruments financiers, interdites dans l'ancien modèle comptable au coût historique, la juste valeur peut inciter les dirigeants à substituer une partie de l'investissement productif par des placements financiers. Le danger sur une allocation efficace des ressources dans les sociétés non financières est alors le redéploiement des actifs de la société suivant une stratégie financière et non dans une logique industrielle. Nous nous questionnons alors sur le rôle de la juste valeur dans la financiarisation des entreprises. De plus, nous tentons de comprendre dans quelle mesure la violation du principe de prudence qui dérive de l'application de la juste valeur influence l'efficience de l'investissement. L'application de la juste valeur amène une constatation symétrique des plus et moins-values latentes. La réalisation de ces valeurs est toutefois subordonnée aux mouvements du marché. Les investisseurs et autres parties prenantes peuvent considérer ces valeurs avec précaution parce qu'elles risquent de n'être que de simples estimations qui optimisent l'image financière de l'entreprise. La réaction des investisseurs qui ont dévalué les titres, suite à la suppression des bénéfices issus d'une constatation audacieuse des revenus en application du SAB 101, témoigne de cette aversion contre l'incertitude. Nous mettons alors l'accent sur le comportement d'investissement en fonction de l'aversion au relâchement de la prudence dans la mesure du résultat. Cette question est d'importance majeure vu que les investisseurs perdent leur confiance dans les marchés financiers lorsqu'ils s'aperçoivent que ces perspectives de gains ou pertes ne sont pas réelles (Enron, Lehman Brothers). Sur un échantillon de firmes canadiennes appartenant à l'indice TSX Composite pour la période entre 2007 et 2011, nos résultats indiquent d'une part que la rentabilité financière des instruments financiers n'intervient pas dans la stratégie d'investissement financier des entreprises et d'autre part ils confirment l'effet modérateur de l'audace sur la relation entre l'information comptable en juste valeur et l'efficience d'investissement. Ce résultat demeure même après avoir contrôlé pour différentes estimations de l'efficience d'investissement. Notre travail contribue, d'une part, à éclairer le débat sur la légitimité de l'emploi de la juste valeur comme mode d'évaluation des actifs et des passifs notamment depuis son rôle présumé dans la dernière crise financière et, d'autre part, les résultats de notre recherche se veulent significatifs dans le contexte de l'adoption, par le Canada, des normes internationales, dont la juste valeur constitue une des pierres angulaires. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : information comptable en juste valeur, stratégies d'investissement, efficience de l'investissement, relâchement de la prudence comptable.

Brazil is a high middle income country where health inequities persist across two systems of health care financing and delivery. The publicly financed system (SUS) is one of the world’s largest health organizations, which is charged with the constitutional mandate to provide comprehensive health care coverage to over 190 million citizens. National Health Conferences (CNS), the core forum for societal participation in health policy making for the SUS, occur every four years. Yet, managers and councillors struggle to decide on how to allocate resources to meet competing populational health needs and demands, and to comply with the directives of the SUS. The purpose of my research is to describe the three most recent CNS, based on a scoping literature review, to evaluate the ethical account of these decision making processes, and to provide recommendations for improving priority setting for health resource allocation for the SUS according to the ethical analysis.

Abstract This research explores the problems of resource allocation during the process of internationalization by small and medium-sized manufacturing firms. The literature largely portrays a positive view of internationalization with respect to increased firm performance or growth. However, particularly for Small and Medium-Sized Enterprises(SMEs), growth through internationalization increases uncertainty and may jeopardize firm performance and even threaten survival of the firm. The literature indicates that some SMEs fail during the process of expanding to foreign markets (Brewer 1981;Ramaswamy 1992; Mudambi and Zahra 2007). Many of these failures are due, in part,to the challenges of allocating limited resources during and after internationalization(Chen and Hsu 2009). Given the challenge of internationalizing, this research examines the influence of resource allocation on firm performance with the aim of providing recommendations on how entrepreneurs can make better resource allocation decisions that in turn may lead to improved performance. To address the problem of allocation of limited resources during and after internationalization, theoretical propositions are developed based on modern portfolio-theory (Markowitz 1952; 1959; 1991) that explains the risk-return tradeoffs with regards to resource allocation to domestic, U.S., and foreign markets and possible effects on firm performance. This research applies a multiple case-study approach based on critical realism, a qualitative philosophical research paradigm. Data collection is through in-depth interviews with executives of twenty-two small- and medium-sized manufacturing firms located in Canada. Within-case and cross-case analyses findings are used to confirm or modify the propositions, resulting in a descriptive model that best explains resource allocation decisions and the effects on performance. The findings indicate that resource allocations to domestic, U.S., and foreign markets have different contributions to overall firm performance. However, the way in which resource allocation trade-offs are decided between these markets is largely dependent on the firms or owners/manager’s disposition to risks and returns. Findings from this research also show that decisions by firm managers to allocate resources to a particular market depend on their assessment or anticipation of risks and the potential mitigation strategies that are required in order to maximize returns. This, consequently, determines the firm’s performance during the process of internationalization. This research contributes to the literature in international entrepreneurship, management of technology, and decision analysis. While there is an extensive body of literature that focuses on the output of internationalization (i.e., where, when, and how firms export their products), few studies have specifically examined the inputs that make this happen (one of these being the allocation of resources). Rugman et al. (2008) examines the resource allocation decision between domestic and foreign markets for Multinational Enterprises (MNEs) and the impact on firm performance. No known study has specifically explored resource allocation decisions between domestic, U.S., and foreign markets for SMEs and the influence on firm performance. This research fills the identified gap by making a significant theoretical contribution to this field by adopting portfolio theory to the challenge of allocating resources between domestic and foreign markets.

The allocation of fishing opportunities is one of the most difficult challenges for high seas fisheries management. There is an ongoing search for equitable and transparent allocation frameworks. This thesis explores whether, under what conditions, and with what shortcomings, a legal concept of equity can provide assistance in the development of such a framework. To this end, it reviews the historical origins of allocation of quotas in international fisheries, and summarizes the current global and regional legal frameworks for allocation and regional practices. It then analyzes whether intergenerational and intra-generational equity is considered in the international legal framework for high seas fisheries, and what the legal and practical implications of their inclusion are. It provides some suggestions on how to integrate intergenerational and intra-generational equity more effectively into allocation decisions. It concludes by highlighting the contribution of law in the search for allocation frameworks.

Cooperative communications is a new wireless networking paradigm that allows networking nodes to collaborate through distributed transmission and signal processing to implement spatial and time signal diversity to combat the effects of fading channels. These systems exploit the wireless broadcast advantage, where transmissions from an omnidirectional antenna can be received by networking nodes that lie within its communication range. Specifically, in cooperative relaying systems the source broadcasts a message to a number of cooperative relays, which in turn resend a processed version of the information to the intended destination nodes, emulating antenna array effects. The destination nodes combine the signals received from the collaborating relays, either to increase the capacity of communication links or to increase the reliability of transmissions between the source and the destination. This is accomplished with an approach similar to that used in recently introduced space-time coding techniques for multiple-input multiple-output (MIMO) communication systems.

No description available.

Long Term Evolution (LTE) constitutes a significant milestone in the evolution of 3G systems towards fourth generation (4G) technologies. The performance targets promised by LTE makes it an ideal solution to accommodate the ever increasing demand for wireless broadband. LTE's promised performance targets were made possible due to improvements such as a simplified system access architecture and a fully IP-based platform. LTE has also great enhancements in its enabling radio technologies by introducing Orthogonal Frequency Division Multiplexing (OFDM) and advanced antenna technologies. In addition, LTE capabilities are further improved with enhanced Quality of Service (QoS) support for multiple data services, such as voice and other multimedia applications. LTE packet scheduling plays an essential role as part of LTE's Radio Resource Management (RRM) to enhance the system's data rate and to support the diverse QoS requirements of mobile services. LTE packet scheduler should intelligently allocate radio resources to mobile User Equipments (UEs) such that the LTE network adheres to its performance requirements. In our work, we perform a performance evaluation of multiple LTE scheduling algorithms proposed for LTE uplink transmission. The evaluation takes place in single and mixed traffic scenarios to exploit the strengths and weaknesses of proposed algorithms. Simulation results illustrated the importance of a scheduler's awareness of uplink channel conditions and QoS requirements in the presence of single and multiple traffic scenarios. Accordingly, we provide recommendations for future scheduling algorithm proposals, and ways to enhance the existing schedulers. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2011-05-07 12:43:54.983

No description available.