This thesis consists of a summary and four papers. The first two papers address political economy and indus-trial organization aspects of agricultural policy, and the last two international aspects of environmental policy. Paper [I] explains Common Agricultural Policy (CAP) subsidies to farmers by the influence of farmer interest-groups with an EU-wide membership. The analysis is based on panel-data for fifteen commodities over the period 1986-2003. Because the CAP is set as an overall EU policy, effective lobbying presents a collective ac-tion problem to the farmers in the EU as a whole. Indicators of lobbying, which are based on this perception, are found to explain part of the variation in agricultural support. In Paper [II], the Bresnahan-Lau framework is used to analyze whether policy reforms, i.e. the two-price sys-tem (an input quota, 1986-1991) and a general deregulation of dairy policy (1991-1994) had any market power effects on the Swedish butter market. The results show that the null hypothesis of no market power cannot be rejected, for any of the specific policy reforms, at any reasonable significance level. Paper [III] concerns the welfare consequences of environmental policy cooperation. It is assumed that coun-tries finance their public expenditures by using distortionary taxes, and that they differ with respect to compe-tition in the labor market. It is shown how the welfare effect of an increase in the expenditures on abatement depends on changes in the environmental damage, employment and work hours. The welfare effect is also related to the strategic interaction among the countries in the prereform equilibrium. In Paper [IV] environmental policy in an economic federation, where each national government faces a mixed tax problem, is addressed. It is assumed that the federal government sets emission targets, which are imple-mented at the national level. It is also assumed that the economic federation is decentralized. The results high-light a strategic role of income and commodity taxation, i.e. each country uses its policy instruments, at least in part, to influence the emission target.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-08-05T13:25:31Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Bruno Nunes_FINAL.pdf: 1523588 bytes, checksum: feea1e49f7dc0fcebbcf54602098e8e1 (MD5) / Made available in DSpace on 2016-08-05T13:25:31Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Bruno Nunes_FINAL.pdf: 1523588 bytes, checksum: feea1e49f7dc0fcebbcf54602098e8e1 (MD5) Previous issue date: 2016-02-19 / CNPq / A growing trend in hiring maintenance services has been observed in companies in general in order to enhance competition and reduce costs. This practice becomes even more evident in the context of health institutions, as they strongly employ technology-intensive equipment that must follow tight quality standards that intend to ensure the continuity of the service and the safety of patients. These characteristics contribute in allowing the maintenance to be executed by the Original Equipment Manufacturer (OEM), since several pre-established procedures must be attended during maintenance. Thus, it becomes relevant to analyze the interaction among customers (hospitals) and the equipment manufacturer in this particular maintenance services market. In the developed model the customers are divided into 2 classes, great size hospitals belong to class 1 and small hospitals belong to class 2 and class 1 customers have priority over class 2 customers. Class 1 customers have the option of hiring an Extended Warranty (EW) with priority or of paying for each maintenance intervention on demand, while class 2 customers have the option of hiring an standard EW (with no priority) or of paying for each maintenance intervention on demand. To model such dynamics a 2-class priority queuing system is implemented. The customers select the option that maximize their expected utilities, as they are risk averse, while the manufacturer needs to set the EW and maintenance intervention prices and select the optimal number of customers of each class to service in order to maximize their expected profit. A Stackelberg Game is used to model the interaction among players, in which the OEM is the leader and the customer is the follower. In the numerical example it has been found that the customers of class 1 decide to hire EW with priority, while class 2 customers decide to pay for maintenance services on demand. Also the OEM decides to service 3 customers of class 1 and 100 customers of class 2, which yields an expected profit of $ 3,204,450. A sensitivity analysis is also performed to analyze how the optimal solution changes due to parameters variations. / Uma tendência crescente para a contratação de serviços de manutenção tem sido observada em empresas em geral com o objetivo de aumentar sua competitividade e reduzir custos. Tal prática se torna ainda mais evidente no contexto de instituições de saúde, já que elas utilizam diversos equipamentos intensivos em tecnologia que precisam se adequar a rígidos padrões de qualidade de forma a garantir a continuidade do serviço e a segurança dos pacientes. Essas características contribuem para que os serviços de manutenção sejam executados pelo fabricante do equipamento, já que diversos procedimentos específicos precisam ser seguidos durante a manutenção. Assim, torna-se relevante analisar a interação entre clientes (hospitais) e o fabricante do equipamento neste mercado particular. No modelo desenvolvido, os clientes foram divididos em 2 classes, hospitais de grande porte pertencem à classe 1 e hospitais pequenos pertencem à classe 2 e os clientes da classe 1 têm prioridade em relação aos clientes da classe 2. Os clientes da classe 1 têm a opção de contratar uma garantia estendida com prioridade ou de pagar por cada intervenção de manutenção sob demanda, já os clientes da classe 2 têm a opção de contratar uma garantia estendida padrão (sem prioridade) ou de pagar por cada intervenção de manutenção sob demanda. Para modelar esta dinâmica um sistema de filas com 2 classes de prioridade foi implementado. Os clientes escolhem a opção que maximiza suas utilidades esperadas, já que são avessos ao risco, enquanto o fabricante deve determinar os preços das garantias estendidas e das intervenções avulsas além do número ótimo de clientes que ele deve atender de forma a maximizar o seu lucro esperado. Para modelar a interação entre os jogadores foi utilizado um Jogo de Stackelberg em que o fabricante é o líder e o cliente, o seguidor. O exemplo numérico apresentado mostra que a decisão ótima para os clientes da classe 1 é adquirir a garantia estendida com prioridade, enquanto para os clientes da classe 2 a decisão-ótima é pagar pelos serviços de manutenção sob demanda. O fabricante decide atender 3 clientes da classe 1 e 100 clientes da classe 2, o que lhe gera um lucro de $ 3,204,450. Uma análise de sensibilidade é apresentada em seguida para investigar como a solução ótima muda em decorrência de variações nos parâmetros.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-08-05T13:45:36Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 2016 02 Dissertação V18.pdf: 847550 bytes, checksum: b3b34305dd3687f0d1a2e2aa1a8ef506 (MD5) / Made available in DSpace on 2016-08-05T13:45:36Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 2016 02 Dissertação V18.pdf: 847550 bytes, checksum: b3b34305dd3687f0d1a2e2aa1a8ef506 (MD5) Previous issue date: 2016-02-19 / CAPEs / A terceirização da manutenção e a adesão da garantia estendida para equipamentos hospitalares tem se tornado uma tendência ao longo das últimas décadas, pois estão relacionadas com a crescente complexidade e modernização dos dispositivos médicos, bem como, com a recorrente prática da exclusividade do fabricante na realização da manutenção. Geralmente, o relacionamento entre a instituição de saúde e o fabricante é conduzido por meio de um documento, especificando questões como: nível de confiabilidade, desempenho operacional, disponibilidade, duração da garantia, preço da manutenção, penalidades e a política de manutenção a ser implementada. Sendo assim, a presente dissertação estuda quantitativamente o problema de garantia estendida para equipamentos hospitalares, por meio da junção de duas ferramentas: o jogo de Stackelberg, designado para estruturar a forma de relacionamento entre as empresas, e o Processo de Renovação Generalizado, responsável processo de falha – reparo do equipamento (reparo imperfeito). Um cenário foi criado para a aplicação de tais métodos. Inicialmente, o fabricante ao vender um equipamento hospitalar também oferece duas possibilidades para a execução da manutenção: a primeira, garantia estendida, e a segunda, serviço sob demanda. Posteriormente, a decisão do hospital é influenciada pela estrutura de preços imposta do fabricante, a confiabilidade do equipamento e o seu grau de aversão ao risco, visto que as falhas do dispositivo são eventos aleatórios. Para ilustrar tal situação, realiza-se um exemplo numérico com dados de falha e reparo de um Angiográfo. O equilíbrio do modelo implica na maximização do lucro esperado do fabricante e o hospital decidindo pela adesão da garantia estendida. Adicionalmente, comparando as soluções do reparo imperfeito com os cenários de reparos perfeito e mínimo, observou-se similaridade nas estratégias para os casos de reparos imperfeito e perfeito, enquanto que, na relação entre os reparos imperfeito e mínimo as estratégias darse- ão de maneira oposta. Finalmente, o lucro esperado do fabricante diminui conforme aumenta o número médio de falhas. / The outsourcing of maintenance and the acquisition of extended warranty for hospital equipment has become a trend over the past few decades, since they are related to the growing complexity, modernization of medical devices and the recurring practice of the manufacturer's exclusivity in performing maintenance services. Generally, the relationship between the health institution and the manufacturer is conducted through a document specifying the following issues: level of reliability, operating performance, availability, warranty period, maintenance price, penalties and maintenance policy to be implemented. Under these circumstances, this thesis analyzes the problem of the extended warranty for clinical equipment by joining two tools: the Stackelberg game, designed to model the relation between companies and the Generalized Renewal Process, employed for modeling failure-repair process (imperfect repair). A scenario was created for the application of such methods. Initially, the manufacturer intends to sell a medical equipment and also offers two maintenance possibilities: first, an extended warranty, and second, maintenance services on demand. Subsequently, the hospital's decision is influenced by manufacturer's price structure, equipment reliability and the degree of risk aversion, since the failures occurrences of the device are random events. To illustrate this situation, an application example with failure and repair data of an Angiography equipment is presented. The equilibrium of model implies in expected profit maximization for the manufacturer and hospital chooses the extended warranty option. In addition, by comparing the solutions of the imperfect repair with perfect and minimal repair scenarios, a similarity in the strategies adopted in cases of imperfect and perfect repairs was observed, while the strategies were opposite when comparing imperfect and minimal repairs. Finally, the expected profit of the manufacturer decreases as the average number of failures increases.

Cette thèse est consacrée à l'étude des législations environnementales et leurs effets sur la chaîne d'approvisionnement. Plus précisément, nous nous intéressons à la législation basée sur le recyclage du produit mais aussi sur les normes de conformité (ROHS). Nous étudions le potentiel de réutilisation ainsi que les aspects environnementaux et économiques de différents systèmes de législation. La solution se présente sous forme d'une combinaison de politiques de récupération qui mène à de meilleurs résultats sur le plan écologique ainsi que sur le plan économique.Dans la deuxième partie de la thèse, Nous étudions la performance comparative des régimes à base sur la législation de récupération avec des problématiques d'innovation et de conception de produits. La politique de réutilisation des produits peut aggraver l’environnement si le cadre de la régulation n'est pas bien défini. Dans la dernière partie, une étude est menée sur le choix des produits dans une chaine d’approvisionnement avec des législations basées sur la récupération et sur la conformité des produits. Nous intégrons les effets de l'incertitude associée à la demande du marché et les paramètres de coût de récupération. Une méthode d'optimisation robuste pour la sélection et distribution des produits est présentée. / Climate change and global temperature rise has made environmental legislations a focal point of discussion. This dissertation is devoted to the study of environmental legislations and their effect on supply chain practices. More precisely, our center of interest is the product recovery based legislation along with compliance based regulations. We explore the reuse potential and the environmental and economical aspects of different product recovery based legislation schemes by modeling a stackelberg game between a social welfare maximizing policy maker and a profit maximizing monopolistic firm and find that a combination of existing recovery policies i.e., a recovery target in combination with incentive structure such as taxation/subsidy may lead to better outcomesnot only from environmental perspective but also from economical aspects. In Chapter 2, we extend the discussion comparative performance of the recovery legislation based schemes in presence of innovation and product design issues and show how unintended environmental outcomes may appear if the policy framework is not adequately designed. In Chapter 3, wecapture the effect of recovery legislation and compliance based legislation on product selection when a firm serves a number of markets. We incorporate the effects of uncertainty associated with market demands and recovery cost parameters and present a robust optimization based method for product selection and allocation decisions.

Conventional medical imaging technologies for cancer diagnosis utilize fixed geometric configuration of the source and the detector to image the target. In this dissertation, we hypothesize that dynamic utilization of source and detector geometry will lead to better performance of medical imaging devices. Interrogating a target in a three dimensional space requires cooperation and coordination between the source and detector positions. The goal of this dissertation is to develop a dynamic imaging method, which will improve the tumor characterization performance, and provide a control scheme appropriate for the dynamic interrogation. This dissertation proposes a bimodal dynamic imaging (BDI) method for improving tumor characterization and a hybrid hierarchical statistical control scheme for the autonomous control of the sources and detectors. The tactile imaging sensor has high specificity but low sensitivity in tumor characterization. The spectral sensor has high sensitivity but low specificity. The BDI system integrates the tactile sensing and the spectral sensing modalities with the capability of dynamic positioning of the source and detector to determine the mechanical and spectral properties of a tumor. The tactile sensing can estimate the mechanical properties of the tumor, such as size, depth, and elastic modulus, while the spectral sensing can determine the absorption coefficient of the tumor through diffuse optical imaging. These properties help us characterize the tumor, and differentiate cancerous tissues from healthy tissues. We designed and experimentally evaluated the BDI system for estimating the size, depth, elastic modulus, and absorption coefficient of embedded inclusions. The system performance in characterizing mechanical properties was then compared to that of the tactile imaging sensor. The proposed BDI method was experimentally validated using fabricated bimodal phantom. The experimental results showed that the tactile imaging system (TIS) estimated the tumor phantom size with 7.23% error; BDI measured the size with 0.8% error. The TIS depth estimation error was 41.83%; BDI reduced the depth measurement error to 20.00%. The TIS elastic modulus estimation error was 96.80%; the BDI method showed 74.79% error. Additionally, BDI estimated the absorption coefficient with 14%-25% estimation error. For further improvement the system performance, this bimodal imaging system is implemented on a dual-arm robot, Baxter, where the laser source and the tactile imaging sensors were mounted on the end-effectors. Each arm of Baxter robot has seven Degree-of- Freedom. This provides more flexibility in terms of interrogating the target compared to the fixed geometric configuration. We devised a hybrid statistical controller for maneuvering the source and the detector of the system. In this control architecture, a high-level supervisory controller was used for the functions at a higher level for coordinating two arms. At lower level, a full-state feedback statistical controller was used to facilitate the minimum position variation. A linear model for the dual-arm Baxter robot was derived for testing the proposed architecture. We performed the simulations of hybrid hierarchical statistical controller on the Baxter model for trajectory tracking. The simulation studies demonstrated accurate sequential task execution for the bimodal dynamic imaging system using a hybrid hierarchical statistical control. / Electrical and Computer Engineering

Abstract With the current technological advancements, stage is being set for new ultra-responsive and robust 5G-enabled applications (e.g., virtual reality, Tactile Internet,…) to deliver critical real-time traffic. The emergence of such critical applications requires new networking models that can handle more connected devices with super high reliability and low latency communications. In the view of these research challenges, this thesis aims to propose new techno-economic models and networking paradigms needed in the redesign of wireless network architectures and protocols to support the connectivity requirements by which operators and users effectively benefit from new opportunities introduced by 5G-enabled applications. In this thesis, new paradigms in wireless network access are presented and analyzed. First, dynamic network architecture (DNA) is introduced, where certain classes of wireless terminals can be turned temporarily into an access point (AP) anytime while connected to the Internet. In this concept, a framework is proposed to optimize different aspects of this architecture. Furthermore, to dynamically reconfigure an optimum topology and adjust it to the traffic variations, a new specific encoding of genetic algorithm (GA) is presented. Then, a distributed user-centric spectrum sharing is developed based on DNA networks to enable user-provided access points pervasively share the unused resources. Next, a flexible cloud-based radio access network (FRAN) is proposed to offload traffic to DNA networks in order to provide low latency communications. In the sequel of the thesis, as a new paradigm, a context-aware resource allocation scheme based on adaptive spatial beamforming and reinforcement learning is proposed. In addition, semi-cognitive radio network (SCRN) as a new spectrum sharing model is developed to improve the utility of primary and secondary owners. / Tiivistelmä Nykyaikaisilla teknologisilla edistysaskeleilla mahdollistetaan uusien 5G-pohjaisien erittäin lyhyen vasteajan ja suuren luotettavuuden sovelluksien ilmestyminen kriittisen reaaliaikaisen informaation välittämiseen (esim. taktiiliset ja virtuaalitodellisuus-sovellukset). Näiden kaltaiset sovellukset vaativat uudenlaisia verkottumismalleja, jotka kykenevät käsittelemään enemmän laitteita suurella toimintavarmuudella ja matalalla latenssilla. Tämä väitöskirja ehdottaa näiden haasteiden valossa uusia teknis-taloudellisia malleja ja verkottumisparadigmoja, joita tarvitaan verkkoarkkitehtuurien ja -protokollien uudelleensuunnittelussa tulevaisuuden sovelluksien tarpeet huomioiden, joiden kautta operaattorit ja käyttäjät voivat hyödyntää tulevien 5G-sovelluksien tuomat mahdollisuudet. Tässä väitöskirjassa esitetään ja analysoidaan uusia paradigmoja langattomaan verkkoliityntään. Ensimmäisenä esitellään dynaaminen verkkoarkkitehtuuri (dynamic network architecture, DNA), missä tietyt langattomat terminaalit voidaan väliaikaisesti muuttaa liityntäpisteiksi milloin vain internetyhteyden ollessa käytettävissä. Tämän konseptin puitteissa ehdotetaan viitekehys sen eri osa-alueiden optimoimiseksi. Tämän lisäksi esitetään uusi spesifinen geneettisen algoritmin (GA) koodaus optimaalisen topologian dynaamiseen konfigurointiin ja sen säätämiseen tietoliikenteen määrän mukaan. Tämän jälkeen esitellään kehitetty hajautettu käyttäjäkeskeinen spektrinjako, joka perustuu DNA-verkkoihin ja joka mahdollistaa käyttämättömien resurssien kokonaisvaltaisen jakamisen käyttäjien kautta. Seuraavaksi työssä ehdotetaan joustavaa pilvipalvelu-pohjaista liityntäverkkoa (flexible cloud-based radio access network, FRAN) käyttäjädatan purkamiseksi DNA-verkoille matalalatenssisen tietoliikenteen tarjoamiseksi. Edellä mainittujen menetelmien seurauksena ehdotetaan uutta paradigmaa: Kontekstiriippuvaista resurssien allokointia perustuen adaptiiviseen spatiaaliseen keilanmuodostukseen ja vahvistusoppimiseen. Näiden lisäksi kehitetään uusi spektrinjakomalli puolikognitiivisille radioverkoille (semi-cognitive radio network, SCRN) ensisijaisien ja toissijaisien käyttäjien utiliteetin parantamiseksi.

No description available.

This dissertation focuses on selected issues in regard to the mathematical modeling of electricity markets. In a first step the interrelations of electric power market modeling are highlighted a crossroad between operations research, applied economics, and engineering. In a second step the development of a large-scale continental European economic engineering model named ELMOD is described and the model is applied to the issue of wind integration. It is concluded that enabling the integration of low-carbon technologies appears feasible for wind energy. In a third step algorithmic work is carried out regarding a game theoretic model. Two approaches in order to solve a discretely-constrained mathematical program with equilibrium constraints using disjunctive constraints are presented. The first one reformulates the problem as a mixed-integer linear program and the second one applies the Benders decomposition technique. Selected numerical results are reported.

Abstract The aim of this thesis is to devise new paradigms on radio resource sharing including cache-enabled virtualized large cellular networks for mobile network operators (MNOs). Also, self-organizing resource allocation for small cell networks is considered. In such networks, the MNOs rent radio resources from the infrastructure provider (InP) to support their subscribers. In order to reduce the operational costs, while at the same time to significantly increase the usage of the existing network resources, it leads to a paradigm where the MNOs share their infrastructure, i.e., base stations (BSs), antennas, spectrum and edge cache among themselves. In this regard, we integrate the theoretical insights provided by stochastic geometrical approaches to model the spectrum and infrastructure sharing for large cellular networks. In the first part of the thesis, we study the non-orthogonal multi-MNO spectrum allocation problem for small cell networks with the goal of maximizing the overall network throughput, defined as the expected weighted sum rate of the MNOs. Each MNO is assumed to serve multiple small cell BSs (SBSs). We adopt the many-to-one stable matching game framework to tackle this problem. We also investigate the role of power allocation schemes for SBSs using Q-learning. In the second part, we model and analyze the infrastructure sharing system considering a single buyer MNO and multiple seller MNOs. The MNOs are assumed to operate over their own licensed spectrum bands while sharing BSs. We assume that multiple seller MNOs compete with each other to sell their infrastructure to a potential buyer MNO. The optimal strategy for the seller MNOs in terms of the fraction of infrastructure to be shared and the price of the infrastructure, is obtained by computing the equilibrium of a Cournot-Nash oligopoly game. Finally, we develop a game-theoretic framework to model and analyze a cache-enabled virtualized cellular networks where the network infrastructure, e.g., BSs and cache storage, owned by an InP, is rented and shared among multiple MNOs. We formulate a Stackelberg game model with the InP as the leader and the MNOs as the followers. The InP tries to maximize its profit by optimizing its infrastructure rental fee. The MNO aims to minimize the cost of infrastructure by minimizing the cache intensity under probabilistic delay constraint of the user (UE). Since the MNOs share their rented infrastructure, we apply a cooperative game concept, namely, the Shapley value, to divide the cost among the MNOs. / Tiivistelmä Tämän väitöskirjan tavoitteena on tuottaa uusia paradigmoja radioresurssien jakoon, mukaan lukien virtualisoidut välimuisti-kykenevät suuret matkapuhelinverkot matkapuhelinoperaattoreille. Näiden kaltaisissa verkoissa operaattorit vuokraavat radioresursseja infrastruktuuritoimittajalta (InP, infrastructure provider) asiakkaiden tarpeisiin. Toimintakulujen karsiminen ja samanaikainen olemassa olevien verkkoresurssien hyötykäytön huomattava kasvattaminen johtaa paradigmaan, jossa operaattorit jakavat infrastruktuurinsa keskenään. Tämän vuoksi työssä tutkitaan teoreettisia stokastiseen geometriaan perustuvia malleja spektrin ja infrastruktuurin jakamiseksi suurissa soluverkoissa. Työn ensimmäisessä osassa tutkitaan ei-ortogonaalista monioperaattori-allokaatioongelmaa pienissä soluverkoissa tavoitteena maksimoida verkon yleistä läpisyöttöä, joka määritellään operaattoreiden painotettuna summaläpisyötön odotusarvona. Jokaisen operaattorin oletetaan palvelevan useampaa piensolutukiasemaa (SBS, small cell base station). Työssä käytetään monelta yhdelle -vakaata sovituspeli-viitekehystä SBS:lle käyttäen Q-oppimista. Työn toisessa osassa mallinnetaan ja analysoidaan infrastruktuurin jakamista yhden ostaja-operaattorin ja monen myyjä-operaattorin tapauksessa. Operaattorien oletetaan toimivan omilla lisensoiduilla taajuuksillaan jakaen tukiasemat keskenään. Myyjän optimaalinen strategia infrastruktuurin myytävän osan suuruuden ja hinnan suhteen saavutetaan laskemalla Cournot-Nash -olipologipelin tasapainotila. Lopuksi, työssä kehitetään peli-teoreettinen viitekehys virtualisoitujen välimuistikykenevien soluverkkojen mallintamiseen ja analysointiin, missä InP:n omistama verkkoinfrastruktuuri vuokrataan ja jaetaan monen operaattorin kesken. Työssä muodostetaan Stackelberg-pelimalli, jossa InP toimii johtajana ja operaattorit seuraajina. InP pyrkii maksimoimaan voittonsa optimoimalla infrastruktuurin vuokrahintaa. Operaattori pyrkii minimoimaan infrastruktuurin hinnan minimoimalla välimuistin tiheyttä satunnaisen käyttäjän viive-ehtojen mukaisesti. Koska operaattorit jakavat vuokratun infrastruktuurin, työssä käytetään yhteistyöpeli-ajatusta, nimellisesti, Shapleyn arvoa, jakamaan kustannuksia operaatoreiden kesken.

Resource allocation in wireless networks is one of the most studied class of problems. Generally, these problems are formulated as utility maximization problems under relevant constraints. The challenges posed by these problems vary widely depending on the nature of the utility function under consideration. Recently, the widespread prevalence of wireless devices prompted researchers and engineers to delve into the security issues of wireless communication. As compared to the wired medium, ensuring security for the wireless medium is more challenging mainly due to the broadcast nature of the transmission. But the ongoing research on physical layer security promises robust and reliable security schemes for wireless communication. Contrary to conventional cryptographic schemes, physical layer security techniques are impregnable as the security is ensured by the inherent randomness present in the wireless medium. In this thesis, we consider several wireless scenarios and propose secrecy enhancing resource allocation schemes for them in the first few chapters. We initially address the problem of secure transmission by following the conventional approach in the secrecy literature|secrecy rate maximization. Needless to say, in these chapters, secrecy rate is the utility function and the constraints are posed by the available power budget. Then we consider a pragmatic approach where we target the signal-to-noise ratio (SNR) of participating nodes and ensure information secrecy by appropriately constraining the SNRs of those nodes. In those SNR based formulations, SNR at the destination is the utility function and we are interested in maximizing it. In the last two chapters, we study two scenarios in a non-secrecy setting. In one of them, end-to-end data rate is the utility, whereas, in the other one, two utility functions|based on revenue generated|are defined for two rational agents in a game-theoretic setting. In the second chapter, we study parallel independent Gaussian channels with imperfect channel state information (CSI) for the eavesdropper. Firstly, we evaluate the probability of zero secrecy rate in this system for (i) given instantaneous channel conditions and (ii) a Rayleigh fading scenario. Secondly, when non-zero secrecy is achievable in the low SNR regime, we aim to solve a robust power allocation problem which minimizes the outage probability at a target secrecy rate. In the third, fourth and fifth chapters, we consider scenarios where the source node transmits a message to the destination using M parallel amplify-and-forward (AF) relays in the presence of a single or multiple eavesdroppers. The third chapter addresses the problem of the maximum achievable secrecy rate for two specific network models: (a) degraded eavesdropper channel with complex channel gain and (b) scaled eavesdropper channel with real-valued channel gains. In the fourth chapter, we consider the SNR based approach and address two problems: (i) SNR maximization at the destination and (ii) Total relay power minimization. In the fifth chapter, we assume that the relay nodes are untrusted and to counter them, we deliberately introduce artificial noise in the source message. For this model, we propose and solve SNR maximization problems for the following two scenarios: (i) Total power constraint on all the relay nodes and (ii) Individual power constraints on each of the relay nodes. In the sixth chapter, we address the problem of passive eavesdroppers in multi-hop wire-less networks using the technique of friendly jamming. Assuming decode-and-forward (DF) relaying, we consider a scheduling and power allocation (PA) problem for a multiple-source multiple-sink scenario so that eavesdroppers are jammed, and source-destination throughput targets are met. When channel state information (CSI) of all the node are available, we intend to minimize the total power consumption of all the transmitting nodes. In the absence of eavesdroppers CSI, we minimize vulnerability region of the network. In chapter seven, the problem of cooperative beamforming for maximizing the achievable data rate of two-hop amplify-and-forward (AF) network (in the absence of eavesdropper(s)) is considered. Along with an individual power constraint on each of the relay nodes, we consider a weighted sum power constraint. To solve this problem, we propose a novel algorithm based on the Quadratic Eigenvalue Problem (QEP) and discuss its convergence. In chapter eight, we study a Stackelberg game between a base station and a multi-antenna power beacon for wireless energy harvesting in a multiple sensor node scenario. Assuming imperfect CSI between the sensor nodes and the power beacon, we propose a utility function that is based on throughput non-outage probability at the base station. We find the optimal strategies for the base station and the power beacon that maximize their respective utility functions.