O serviço ecossistêmico de regulação climática global (SERCG) ofertado pelas florestas é reconhecido pelo seu papel crucial na mitigação da mudança climática. Tais ecossistemas atuam como sumidouros de carbono atmosférico por meio do CO2 sequestrado e armazenado nos tecidos vivos dos vegetais. Porém, processos de continuo desmatamento afetam negativamente a capacidade desses ecossistemas em ofertar o SERCG, especialmente em florestas tropicais que possuem alto potencial de ofertar o serviço e sofrem forte pressão devido ao desenvolvimento agroindustrial. As paisagens atlânticas brasileiras são exemplos dessa condição, em especial no estado de São Paulo, onde a vegetação natural foi primordialmente convertida em pastagens e silvicultura. Avaliar e gerenciar os estoques e fluxos de serviços dos ecossistemas em paisagens espacialmente heterogêneas constitui um dos principais desafios da ciência da sustentabilidade da paisagem. Frente a esse contexto, o presente estudo tem o objetivo de avaliar os estudos sobre a valoração ecológica do SERCG da floresta tropical e analisar a oferta deste serviço em paisagens atlânticas pressionadas pela atividade pecuária. Inicialmente, investigamos as tendências e lacunas que envolvem a pesquisa dos atributos biofísicos do SERCG nas florestas tropicais e subtropicais na escala pan-tropical através de uma revisão sistemática da literatura sobre o tema nos últimos 20 anos, de acordo com uma abordagem exploratória qualitativa. Constatamos que as estimativas de estoque de carbono das florestas tropicais apresentam alta variabilidade, que os fatores de influência mais recorrentes sobre o SERCG na literatura são as mudanças no uso da terra e a riqueza de espécies e que o SERCG possui maior número de relações de sinergia que de trade-off com outros SEs. Em um segundo momento, analisamos a oferta do serviço de regulação em paisagens atlânticas do Vale do Paraíba do Sul (SP), considerando o processo de substituição de floresta nativa por campo antrópico. Levantamos dados em campo para o cálculo de biomassa acima do solo de fragmentos florestais em diferentes estágios sucessionais e em campo antrópico, e transformamos esses dados em estoques de carbono. Os dados subsidiaram os cálculos de SERCG para 16 paisagens que tinham diferentes proporções de áreas de floresta e campo. Também avaliamos a influência da configuração da paisagem sobre a produção de biomassa dos remanescentes florestais. Obtivemos valores de estoque de carbono de 16,9±7,25 MgC há-1 para a floresta inicial, 34,8±12,05 MgC ha-1 para floresta intermediária-avançada e 0,53±0,26 MgC ha-1 para campo antrópico. Identificamos que a distância ao fragmento mais próximo diminui a biomassa das florestas em estágio inicial, enquanto a área média dos fragmentos localizados em um raio de 500 m ao redor do fragmento amostrado aumenta a biomassa das florestas em estágio intermediário-avançado. Destacamos o fato de que as paisagens avaliadas com > 40% do território florestado possuem um diferencial na contribuição da oferta do SERCG, devido ao aumento em número e área de fragmentos de floresta em estágio intermediário-avançado. Apesar do contraste entre a contribuição dos pequenos fragmentos em estágio inicial e os de estágio mais avançado, a ocorrência dos primeiros implica em uma maior oferta do SERCG em escala de paisagem. Ademais, a conservação desses fragmentos não só influenciaria na oferta do serviço de regulação climática, mas também na oferta de outros com os quais apresenta relações sinérgicas / The global climate regulation ecosystem service (GCRES) provided by forests is recognized for its crucial role in mitigating climate change. These ecosystems act as sinks of atmospheric carbon by sequestering and stocking CO2 in the living tissues of plants. However, continuous deforestation processes decreases its capacity to supply GCRES, especially in tropical forests which have high potential to provide the service and suffer strong pressure due to agroindustrial development. Brazilian Atlantic landscapes are examples of this condition, especially in the state of São Paulo, where natural vegetation was primarily converted into cattle pastures and forestry. Assessing and managing ecosystem services stocks and flows in spatially heterogeneous landscapes is one of the major challenges of landscape sustainability science. In this context, our objective is to evaluate the studies on the ecological valuation of GCRES in tropical forest and to analyse the supply of this service in Atlantic landscapes pressured by livestock activity. Initially, we investigated the trends and gaps that involve the biophysical attributes of GCRES in tropical and subtropical forest at a pan-tropical scale through a systematic review of the literature on the subject in the last 20 years, according to a qualitative exploratory approach. We found that (1) estimates of carbon stock from forests show high variability; (2) the most recurrent factors that influence on GCRES are land use and species richness; and (3) GCRES has a greater number of synergy relations with other SEs compared to trade-off relations. Secondly, we analysed the supply of the regulation service in Atlantic landscapes of the Paraiba do Sul Valley (SP, BR), considering the process of replacing native forest by pasturelands. We collected field data to calculate pasture and forest fragments aboveground biomass at different successional stages, and transformed these data into carbon stocks. This data subsidized the calculations of GCRES supply for 16 landscapes that had different proportions of forest and pasture areas. We also evaluated the influence of landscape configuration on forest remnants biomass production. We found carbon stock values of 16.9 ± 7.25 MgC ha-1 in initial forest, 34.8 ± 12.05 MgC ha-1 in intermediate-advanced forest and 0.53 ± 0.26 MgC ha-1 in cattle pastures. We identified that the distance to the nearest fragment decreases the early-stage forest biomass, while the average area of fragments located within a radius of 500 m around the sampled fragment increases the intermediate-advanced stage forest biomass. We highlight the fact that the evaluated landscapes with more than 40% of forested area have a differentiated contribution to the SERCG supply due to the increase in number and area of intermediate-advanced stage forest fragments. In spite of the contrast between the contribution of small fragments in the early stages and those of more advanced stage, the presence of the former implies a greater supply of SERCG at the landscape scale. In addition, the conservation of these fragments would not only influence the supply of the climate regulation service, but also the supply of other services with which it has synergistic relations

Bolag står ständigt inför beslut kring val av finansiering och dessa beslut resulterar i bolagens kapitalstruktur. Kapitalstrukturen har undersökts sedan en lång tid tillbaka och flera olika teorier har växt fram. Än idag finns det dock ingen teori som kan förklara kapitalstrukturen på ett tillfredsställande sätt. Eftersom det inte finns några tydliga tecken på att det finns en optimal kapitalstruktur eller hur en sådan skulle kunna se ut, kan kapitalstrukturen variera. Denna undersökning har tagit fasta på två av de mest kända teorierna för att förklara kapitalstrukturen, trade-off teorin och pecking order teorin. Undersökningen har en tvärsnittsdesigns utformning och studerar hur lönsamhet, tillväxt, storlek, materiella tillgångar, likviditet, icke-skuld skattesköld och bransch påverkar kapitalstrukturen. Fokus ligger på den svenska marknaden och ämnar att kunna generalisera kring svenska börsnoterade bolag. Resultatet av denna undersökning bidrar till en ökad förståelse för kapitalstrukturen men vi är långt ifrån en fullständig bild av ämnet. Undersökningens slutsatser skiljer sig till viss del från tidigare forskning eftersom den hittar stöd för båda teorierna. Ingen av teorierna går dock att applicera i sin helhet på den svenska marknaden vilket tyder på att forskningsområdet fortfarande behöver utvecklas och nya idéer tillkomma. / Companies are constantly faced with making decisions regarding their choice of financing and these decisions result in the company’s capital structure. The capital structure has been studied for a long time and several theories have emerged. Still to this day there’s no theory that can explain the capital structure in a satisfying way. Since there are no clear signs that an optimal capital structure exists nor how one would look, the capital structure can vary. This study has its foundation in two of the most well-known theories that try to explain capital structures, the trade-off theory and the pecking order theory. This cross-sectional study examines how profitability, growth, size, tangible assets, liquidity, non-debt tax shield and industry affect capital structure. The focus lies on the Swedish market and intends to generalize about listed Swedish companies. The result of this paper contributes to an increased understanding of capital structure but we are far from a complete comprehension of the subject. The conclusion of this study partially differs from previous research as it finds support for both theories. However none of the theories are applicable on the Swedish market as a whole which suggests that further research is required along with the addition of new ideas. This paper is written in Swedish.

A ocorrência de distúrbios impacta a diversidade de estratégias de vida em comunidades e a evolução de estratégias de vida em populações. Na Ecologia, o distúrbio é estudado enquanto fator ambiental que altera a disponibilidade de recursos e a abundância das populações, ocasionando a exclusão competitiva de espécies menos favorecidas a depender da intensidade e da frequência de sua ocorrência. Na Biologia Evolutiva, o distúrbio é avaliado enquanto pressão que, dependendo de sua regularidade no ambiente, determina a intensidade da resposta evolutiva das espécies e, assim, a adaptação a estratégias de vida de maior aptidão. Ainda que haja separação entre as duas áreas, a dinâmica ecológica influencia a dinâmica evolutiva e vice-versa. Estudos que integram Ecologia e Evolução têm sido cada vez mais recorrentes, no entanto, poucos ou nenhum consideram o distúrbio. Neste trabalho, utilizamos um modelo baseado em indivíduo para criar cenários nos quais os processos de adaptação e exclusão competitiva de espécies possam ocorrer, tanto conjunta quanto isoladamente, a fim de entender como o distúrbio determina as estratégias de vida presentes em comunidades sob dinâmicas ecológicas, evolutivas e eco-evolutivas. No modelo, as estratégias de vida são atributos herdáveis definidos por um trade-off entre longevidade e fecundidade. O cenário evolutivo foi composto por populações (apenas uma espécie) com mutação; o cenário ecológico, por diversas espécies sem mutação e o cenário eco-evolutivo, por diversas espécies com mutação. Observamos que o distúrbio esteve positivamente relacionado com a predominância de indivíduos fecundos em todos os cenários, mas o efeito do distúrbio sobre a diversidade de estratégias variou. Nos cenários evolutivo e eco-evolutivo, a diversidade de estratégias aumentou com a intensificação do distúrbio, enquanto no cenário ecológico a diversidade caiu. Isso indica a importância da mutação como fonte de novas variantes da estratégia quando há alta renovação de indivíduos da comunidade, condicionada pela mortalidade elevada. Apenas no cenário eco-evolutivo houve um pico de heterogeneidade de estratégias em níveis intermediários de distúrbio. Neste cenário, o isolamento reprodutivo das espécies, em contraposição à pan-mixia que ocorre dentro das populações, permite que as espécies difiram em relação à sua estratégia de vida média. Em paralelo, a entrada constante de variantes de estratégias por mutação previne a extinção definitiva das estratégias do sistema. Assim, quando o nível de distúrbio é intermediário, tanto espécies mais fecundas quanto espécies mais longevas conseguem coexistir na comunidade. Dado que os diferentes cenários resultaram em padrões distintos de frequência relativa de estratégias de vida, este trabalho evidencia a importância de estudarmos o efeito do distúrbio na estrutura e na dinâmica de comunidades unindo processos que são tipicamente estudados de forma isolada pela Ecologia e pela Biologia Evolutiva / Disturbance events impact life strategy diversity in communities and life strategy evolution in populations. In the field of Ecology, disturbance occurrence is studied while an environmental factor that alters resource availability and populations abundance, causing competitive exclusion of less favorable life strategies depending on disturbance frequency and intensity. In the field of Evolutionary Biology, disturbance is evaluated as a pressure, depending on its spatial and temporal regularity, that determines the intensity of species\' evolutionary response and, as a consequence, the adaptation towards the fittest life strategy. Although there is a separation between these two fields of knowledge, ecological dynamics influence evolutionary dynamics and the other way around. Studies that mix Ecology and Evolution are becoming more common, but few or none of them takes disturbance in consideration. Here, we use an individual-based model to generate contexts in which adaptation and competitive exclusion might act apart and together in order to understand how disturbance determines life strategies that occur in communities under ecological, evolutionary and eco-evolutionary dynamics. In the model, life strategy is an inheritable character defined for a trade-off between longevity and fecundity. Simulations from the evolutionary context were composed by one population under mutation acting, simulations from the ecological context by various species without mutation and simulations from the eco-evolutionary context by various species with mutation occurrence. We observed that disturbance was positively correlated with fecund individuals preponderance in all contexts but that disturbance effect on life strategy diversity varied between the different contexts. In the evolutionary and the eco-evolutionary contexts, life strategy diversity increased with disturbance raise, while in the ecological context diversity decreased. This result evidences the mutation role as a source of new life strategy variants when there is a high renovation of individuals given by raised mortality. Only in the eco-evolutionary context there was an interspecific heterogeneity peak on intermediate levels of disturbance. In this scenario, species reproductive isolation, in contrast to populations panmixy, allows species to differ in relation to its life strategies. In parallel to this, the constant input of new life strategy variants by mutation prevents the definite extinction of life strategies from the system. Therefore, when disturbance level is intermediate, productive species as well as long-lived ones are able to coexist. Given that the different contexts resulted in varied patterns of life strategies\' relative frequency, this study evidences the importance of studying disturbance effect on communities structure and dynamics unifying processes that are typically separated between Ecology and Evolution fields

A comparação entre duas teorias na área de finanças sobre estrutura de capital nas empresas é o objetivo deste trabalho. Usando testes desenvolvidos por Shyam-Sunder & Myers (1999) e Rajan & Zingales (1995), os dados de empresas brasileiras, não financeiras, de capital aberto foram analisados entre os anos de 2000 e 2010 para verificar se preferiram os comportamentos previstos na Static Trade-off Theory ou os da Pecking Order Theory. As maneiras de se financiar e as causas e conseqüências dessas decisões nas empresas são importantes questões que vêm sendo debatidas em inúmeros trabalhos acadêmicos. Este trabalho procurou analisar a bibliografia relacionada ao tema e replicar testes realizados no exterior, visando verificar as semelhanças, diferenças e os motivos relacionados a tais resultados. Os resultados obtidos apontam para a provável preferência do comportamento previsto pela Pecking Order Theory, isto é, as empresas estudadas, no período analisado, usaram, em primeiro lugar, recursos gerados internamente (caixa operacional), usando em segundo lugar recursos de terceiros, por meio de empréstimos bancários ou emissão de debêntures, somente emitindo ações como última alternativa. Outra conclusão foi que as empresas brasileiras de capital aberto provavelmente não procuram alcançar ou manter uma meta ideal de endividamento, que equilibre os custos e benefícios gerados pelos empréstimos. / The comparison between two theories in the finance area of capital structure in business is the goal of this work. Using tests developed by Shyam-Sunder & Myers (1999) and Rajan & Zingales (1995), the data of Brazilian non-financial publicly traded were analyzed between the years 2000 and 2010 to determine whether they preferred the expected behaviors in the Static Trade-off Theory or the Pecking Order Theory. The ways to finance and the causes and consequences of these decisions in organizations are important issues that have been discussed in numerous scholarly works. This study sought to examine the literature related to the theme and replicating tests performed abroad in order to verify the similarities, differences and the reasons related to such results. The results indicate the problabe preference behavior provided by Pecking Order Theory, ie the companies studied in the period analyzed, used, first, internally generated funds (operating cash), second using third-party funds through bank loans or issuance of bonds or issuance of bonds, sending shares only as a last resort. Another conclusion is that Brazilian companies traded problaby did not seek to achieve or maintain an ideal goal of indebtedness, wich balances the costs and benefits generated by the loans.

Evaluer le vécu des examens complémentaires en terme d'utilité est pertinent car cela permet de prendre en compte cette donnée dans l'évaluation médico-économique des examens. Le Standard gamble n'a jamais été utilisé pour mesurer l'utilité des examens ; son application dans ce cas pose des problèmes méthodologiques liés à la nature temporaire de l'état évalué. Nous proposons une adaptation du Standard gamble chaîné (SGc) pour mesurer l'utilité des examens. Nous avons mené une étude transversale pour évaluer le vécu des examens du dépistage et du diagnostic initial du cancer du sein en pratique clinique courante. Le vécu a été mesuré en terme (1) d'utilité avec le SGc et une méthode dérivée du Time trade-off, le Wait trade-off (WTO) et (2) de qualité de vie avec un questionnaire standardisé (index TMI). Dans 5 services de radiologie de Montpellier et sa région, 185 patientes ayant eu une mammographie +/- échographie mammaire (68), une IRM mammaire (60) ou une biopsie du sein (57) avec un résultat négatif ont été interrogées après l'annonce du résultat. Les scénarios du SGc ont été bien compris par les patientes (temps d'entretien : 20-30 minutes). Dans les repères (e0, e1) et (décès, e1), 61.0% et 84.0% des patientes avaient une utilité égale à 1. L'utilité du SGc dans le repère (e0, e1) variait avec le type d'examen (p=0.12) et était associé à certaines variables de la qualité de vie (p=0.11 et p=0.036). La mesure n'était pas corrélée avec le WTO. Dans le repère (décès, pleine santé), la désutilité moyenne de l'examen obtenue par le SGc et par le WTO était : 0.0004 (et=0.0015) et 0.0010 (et=0.0031) pour la mammographie, 0.0004 (et=0.0027) et 0.0011 (et=0.0027) pour l'IRM mammaire et 0.0014 (et=0.0073) et 0.0036 (et=0.0083) pour la biopsie du sein. En conclusion, le SGc était compréhensible par les patients mais montrait un effet plafond important quand la mesure était rapportée dans le repère (décès, e1) ; cet effet devra être pris en compte dans les utilisations ultérieures de la mesure. / To evaluate the health impact of diagnostic testing in terms of utility is relevant because introducing this data in the economic evaluation of tests. The Standard gamble has never been used to measure the utility of diagnostic tests; there is methodological problems related to the temporary nature of the condition evaluated. We propose an adaptation of the chained Standard gamble (SGc) to measure the utility of diagnostic tests. A cross-sectional study was conducted to evaluate the health impact of the screening and diagnostic tests of breast cancer in clinical practice. The health impact was measured in terms of (1) utility with the SGc and an adapted version of the Time trade-off, the Wait trade-off (WTO) and (2) quality of life with a standardized questionnaire (index TMI). In 5 departments of radiology in Montpellier area, 185 patients who had a mammography +/- breast echography (68) or a breast MRI (60) or a breast biopsy (57) with a negative result were interviewed after the announcement of the results. The patients understood well the SGc scenarios (interview time : 20-30 minutes). In (e0, e1) and (death, e1), 61.0% and 84.0% of patients had utility equal to 1. The utility of the SGc in (e0, e1) varied with the type of test (P=0.12) and was associated with some variables of quality of life (P=0.11 and P=0.036). The measure was not correlated with the WTO. In (death, perfect health), the average disutility of the test measured by the SGc and the WTO was: 0.0004 (SD=0.0015) and 0.0010 (SD=0.0031) for the mammography, 0.0004 (SD=0.0027) and 0.0011 (SD=0.0027) for the breast MRI and 0.0014 (SD=0.0073) and 0.0036 (SD=0.0083) for the breast biopsy. In conclusion, the SGc was understandable by patients but showed a significant ceiling effect in (death, e1); this effect should be taken into account in subsequent uses of the measure.

Purpose: The thesis purpose is to, with regards to relevant theories, explain how the variables industry affiliation, growth, uniqueness and tangiability affect modern, swedish firms capital structure. Method: A quantitative method along with a deductive approach has been used to make this study. Multiple regression analysis has been applied in order to identify statistical relationships between various variables. Conclusion: The empirical results can only to a certain degree confirm what the theories are claiming. The statistical relationship the growth, profitability, uniqueness in a firm has with leverage is negative. Moreover, tangibility turned out to have a positive relationship to leverage, which coincides with said theories. / Syfte: Uppsatsens syfte är att utifrån relevanta teorier förklara hur variablerna lönsamhet, branschtillhörighet, tillväxt, unikhet och tillgångsstruktur påverkar svenska bolags kapitalstruktur. Metod: En kvantitativ metod med deduktiv ansats har använts för att möjliggöra denna studie. Multipel regressionsanalys har tillämpats för att statistiskt kunna identifiera samband mellan olika variabler. Slutsats: Resultatet stämmer nästan genomgående med teoriernas antaganden. Sambandet mellan tillväxt, lönsamhet, unikhet mot skuldsättningen är negativt. Det visade sig dessutom att det finns ett positivt samband mellan tillgångsstruktur och skuldsättningsgrad, vilket stämmer med vad teorierna hävdar.

As formas de defesa encontradas na natureza são incrivelmente diversas e envolvem estratégias que minimizam as chances de encontro com o predador ou as chances de escape diante de um ataque. A liberação de substâncias químicas é uma forma de defesa amplamente difundida entre artrópodes e vários estudos já demonstraram sua eficiência contra o ataque de predadores. Apesar de trazerem benefícios óbvios em termos de defesa, a produção de vários desses compostos químicos deve ser custosa para as presas. Esta tese teve como objetivo geral explorar os custos da produção de defesas químicas em um grupo particular de artrópodes, os opiliões. No capítulo 1, investigamos como a produção de ovos pode comprometer a produção de defesas químicas (benzoquinonas) e quais as conseqüências da redução do volume de secreção liberada sobre a capacidade de defesa das fêmeas de Acutisoma longipes. Nossos resultados apontam que a quantidade de secreção produzida por fêmeas ovígeras é quase 50% inferior à das fêmeas não-ovígeras. Como conseqüência, a secreção liberada por fêmeas ovígeras é menos eficiente em deter formigas e aranhas do que a secreção liberada por fêmeas não-ovígeras. No capítulo 2, investigamos como a quantidade e a qualidade da dieta influenciam a produção de defesas químicas (benzoquinonas) em Magnispina neptunus. Demonstramos que a produção de defesas químicas é condição dependente, pois indivíduos bem alimentados produziram mais secreção que indivíduos mal alimentados. Entretanto, indivíduos que receberam aporte extra dos precursores da secreção não incrementaram nem a quantidade total nem a concentração da secreção. Por fim, o capítulo 3 teve como objetivo investigar possíveis demandas conflitantes (trade-offs) entre o esforço de acasalamento (produção de armamentos) e o esforço somático (defesas químicas) de machos e fêmeas em um clado de opiliões neotropicais. Usando uma abordagem comparativa, mostramos que fêmeas produzem mais defesas químicas (benzoquinonas) que machos, mas não há uma relação negativa entre o dimorfismo sexual morfológico e o dimorfismo na quantidade de defesas químicas produzidas por machos e fêmeas. Coletivamente, os resultados obtidos aqui apontam que a produção de defesas químicas em opiliões é custosa e que está sujeita a demandas conflitantes com outros componentes de aptidão. / The forms of animal defenses found in nature are incredibly diverse and comprise many strategies that minimize the changes of a prey being detected or attacked by a predator. The emission of chemical secretions is a widespread defense among arthropods, and several studies have already demonstrated the efficiency of chemical defenses against predation. Although chemical defenses confer obvious survival benefits, the production of deterrent compounds may be costly for the individuals. The main goal of this thesis was to evaluate the costs of producing chemical defenses in a particular arthropod group, the harvestmen. In chapter 1 we investigated how egg production may compromise the production of chemical defenses (benzoquinones) by females of Acutisoma longipes, and whether a reduction in the amount of secretions released by ovigerous females make then more vulnerable to predation. Our results indicate that ovigerous females produce almost 50% less secretion than non-ovigerous females. Moreover, the low amount of secretion released by ovigerous females is less efficient than the amount released by non−ovigerous females in deterring ants and spiders. In chapter 2 we investigated how the quantity and quality of food influence the production of chemical defenses (benzoquinones) in Magnispina neptunus. We demonstrate that the production of chemical defenses is clearly condition dependent because well fed individuals produced more secretion than poorly fed individuals. However, individuals that received in the diet an input of the benzoquinones\' precursor did not show an increase in the amount and concentration of secretion released. Finally, in chapter 3 we investigated possible trade-offs between mating effort (i.e., investment in weaponry) and somatic effort (i.e., investment in chemical secretions) in males and females of several harvestman species belonging to the family Gonyleptidae. Using a comparative approach, we showed that females consistently produce more secretion than males, but there is no negative relationship between morphological sexual dimorphism and sexual dimorphism in the amount of secretion released by males and females. Taken together, our findings indicate that the production of chemical defenses in harvestmen is costly and is under allocation trade-offs with other fitness components.

In this thesis, different aspects of lattice-based precoding and decoding for the transmission of digital and analog data over MIMO fading channels are investigated: 1) Lattice-based precoding in MIMO broadcast systems: A new viewpoint for adopting the lattice reduction in communication over MIMO broadcast channels is introduced. Lattice basis reduction helps us to reduce the average transmitted energy by modifying the region which includes the constellation points. The new viewpoint helps us to generalize the idea of lattice-reduction-aided precoding for the case of unequal-rate transmission, and obtain analytic results for the asymptotic behavior of the symbol-error-rate for the lattice-reduction-aided precoding and the perturbation technique. Also, the outage probability for both cases of fixed-rate users and fixed sum-rate is analyzed. It is shown that the lattice-reduction-aided method, using LLL algorithm, achieves the optimum asymptotic slope of symbol-error-rate (called the precoding diversity). 2) Lattice-based decoding in MIMO multiaccess systems and MIMO point-to-point systems: Diversity order and diversity-multiplexing tradeoff are two important measures for the performance of communication systems over MIMO fading channels. For the case of MIMO multiaccess systems (with single-antenna transmitters) or MIMO point-to-point systems with V-BLAST transmission scheme, it is proved that lattice-reduction-aided decoding achieves the maximum receive diversity (which is equal to the number of receive antennas). Also, it is proved that the naive lattice decoding (which discards the out-of-region decoded points) achieves the maximum diversity in V-BLAST systems. On the other hand, the inherent drawbacks of the naive lattice decoding for general MIMO fading systems is investigated. It is shown that using the naive lattice decoding for MIMO systems has considerable deficiencies in terms of the diversity-multiplexing tradeoff. Unlike the case of maximum-likelihood decoding, in this case, even the perfect lattice space-time codes which have the non-vanishing determinant property can not achieve the optimal diversity-multiplexing tradeoff. 3) Lattice-based analog transmission over MIMO fading channels: The problem of finding a delay-limited schemes for sending an analog source over MIMO fading channels is investigated in this part. First, the problem of robust joint source-channel coding over an additive white Gaussian noise channel is investigated. A new scheme is proposed which achieves the optimal slope for the signal-to-distortion-ratio (SDR) curve (unlike the previous known coding schemes). Then, this idea is extended to MIMO channels to construct lattice-based codes for joint source-channel coding over MIMO channels. Also, similar to the diversity-multiplexing tradeoff, the asymptotic performance of MIMO joint source-channel coding schemes is characterized, and a concept called diversity-fidelity tradeoff is introduced in this thesis.

In this thesis, different aspects of lattice-based precoding and decoding for the transmission of digital and analog data over MIMO fading channels are investigated: 1) Lattice-based precoding in MIMO broadcast systems: A new viewpoint for adopting the lattice reduction in communication over MIMO broadcast channels is introduced. Lattice basis reduction helps us to reduce the average transmitted energy by modifying the region which includes the constellation points. The new viewpoint helps us to generalize the idea of lattice-reduction-aided precoding for the case of unequal-rate transmission, and obtain analytic results for the asymptotic behavior of the symbol-error-rate for the lattice-reduction-aided precoding and the perturbation technique. Also, the outage probability for both cases of fixed-rate users and fixed sum-rate is analyzed. It is shown that the lattice-reduction-aided method, using LLL algorithm, achieves the optimum asymptotic slope of symbol-error-rate (called the precoding diversity). 2) Lattice-based decoding in MIMO multiaccess systems and MIMO point-to-point systems: Diversity order and diversity-multiplexing tradeoff are two important measures for the performance of communication systems over MIMO fading channels. For the case of MIMO multiaccess systems (with single-antenna transmitters) or MIMO point-to-point systems with V-BLAST transmission scheme, it is proved that lattice-reduction-aided decoding achieves the maximum receive diversity (which is equal to the number of receive antennas). Also, it is proved that the naive lattice decoding (which discards the out-of-region decoded points) achieves the maximum diversity in V-BLAST systems. On the other hand, the inherent drawbacks of the naive lattice decoding for general MIMO fading systems is investigated. It is shown that using the naive lattice decoding for MIMO systems has considerable deficiencies in terms of the diversity-multiplexing tradeoff. Unlike the case of maximum-likelihood decoding, in this case, even the perfect lattice space-time codes which have the non-vanishing determinant property can not achieve the optimal diversity-multiplexing tradeoff. 3) Lattice-based analog transmission over MIMO fading channels: The problem of finding a delay-limited schemes for sending an analog source over MIMO fading channels is investigated in this part. First, the problem of robust joint source-channel coding over an additive white Gaussian noise channel is investigated. A new scheme is proposed which achieves the optimal slope for the signal-to-distortion-ratio (SDR) curve (unlike the previous known coding schemes). Then, this idea is extended to MIMO channels to construct lattice-based codes for joint source-channel coding over MIMO channels. Also, similar to the diversity-multiplexing tradeoff, the asymptotic performance of MIMO joint source-channel coding schemes is characterized, and a concept called diversity-fidelity tradeoff is introduced in this thesis.

In this thesis, meta-heuristic algorithms are developed to obtain optimum or near optimum solutions for the time-cost-resource trade-off and resource leveling problems in project scheduling. Time cost trade-off, resource leveling, single-mode resource constrained project scheduling, multi-mode resource constrained project scheduling and resource constrained time cost trade-off problems are analyzed. Genetic algorithm simulated annealing, quantum simulated annealing, memetic algorithm, variable neighborhood search, particle swarm optimization, ant colony optimization and electromagnetic scatter search meta-heuristic algorithms are implemented for time cost trade-off problems with unlimited resources. In this thesis, three new meta-heuristic algorithms are developed by embedding meta-heuristic algorithms in each other. Hybrid genetic algorithm with simulated annealing presents the best results for time cost trade-off. Resource leveling problem is analyzed by five genetic algorithm based meta-heuristic algorithms. Apart from simple genetic algorithm, four meta-heuristic algorithms obtained same schedules obtained in the literature. In addition to this, in one of the test problems the solution is improved by the four meta-heuristic algorithms. For the resource constrained scheduling problems / genetic algorithm, genetic algorithm with simulated annealing, hybrid genetic algorithm with simulated annealing and particle swarm optimization meta-heuristic algorithms are implemented. The algorithms are tested by using the project sets of Kolisch and Sprecher (1996). Genetic algorithm with simulated annealing and hybrid genetic algorithm simulated annealing algorithm obtained very successful results when compared with the previous state of the art algorithms. 120-activity multi-mode problem set is produced by using the single mode problem set of Kolisch and Sprecher (1996) for the analysis of resource constrained time cost trade-off problem. Genetic algorithm with simulated annealing presented the least total project cost.