• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 396
  • 75
  • 68
  • 21
  • 20
  • 10
  • 6
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 607
  • 130
  • 103
  • 88
  • 86
  • 85
  • 84
  • 81
  • 78
  • 78
  • 75
  • 66
  • 63
  • 57
  • 54
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
571

Impact of Climate and Soil Variability on Crop Water Productivity and Food Security of Irrigated Agriculture in Northern Togo (West Africa)

Gadedjisso-Tossou, Agossou 12 March 2020 (has links)
West Africa is subject to frequent yield losses due to erratic rainfall and degraded soils. At the same time, its population is expected to double by 2050. This situation is alarming in northern Togo, a West African dry savannah area, where rainfed maize is a staple food. Thus, it is necessary to improve agricultural productivity, e.g., by evaluating and introducing alternative irrigation management strategies, which may be implemented in this region. For this purpose, the present investigation focused on evaluating the potential of deficit and supplemental irrigation, as well as assessing the impact of climate and soil variability on maize yield under irrigated agriculture using irrigation optimisation strategies in northern Togo. The Optimal Climate Change Adaption Strategies in Irrigation (OCCASION) framework was adapted and employed to address the research objectives. It involves: (i) a weather generator for simulating long-term climate time series; (ii) the AquaCrop model, which was utilised to simulate the irrigation during the growing periods and the maize yield response to given irrigation management strategies; and (iii) a problem-specific algorithm for optimal irrigation scheduling with limited water supply. Five irrigation management strategies viz. T1: no irrigation (NI), T2: controlled deficit irrigation (CDI) and T3: full irrigation (FI) in the wet season, T4: controlled deficit irrigation (CDI) and T5: full irrigation (FI) in the dry season were assessed regarding their impact on maize yield in northern Togo. The results showed high variability in rainfall during the wet season, which led to substantial variability in the expected yield for NI. This variability was significantly lessened when optimised supplemental irrigation management strategies (CDI or FI) were applied. This also holds for the irrigation scenarios under the dry season. Finally, these findings were validated by an irrigation field experiment conducted at an agricultural research institute in northern Togo. Under a moderate level of deficit irrigation during the vegetative and reproductive growth stages, the above-ground biomass and the maize grain yield were reduced. However, a moderate level of deficit irrigation during the vegetative growth stage could result in similar values of water productivity to that of fully irrigated treatment. It was found that, based on the values of the statistical indicators, AquaCrop has accurately simulated the maize grain yield for all the irrigation strategies evaluated. The results of this study revealed that climate variability might engender a higher variability in the maize yields of northern Togo than soil variability does. Large- and smallscale water harvesting, access to groundwater, and irrigation infrastructures would be required for implementing the irrigation management strategies assessed in this study.:Declaration iii Declaration of Conformity v Dedication vii Acknowledgements ix Abstract xi Table of Contents xv List of Figures xvii List of Tables xix List of Acronyms and Abbreviations xxi 1. Introduction 1 1.1 Background and Problem Statement 1 1.1.1 Global Fresh and Agricultural Water Use 1 1.1.2 Erratic Rainfall, Rising Temperatures, and Soil fertility depletion in West Africa 2 1.1.3 Transboundary Water Issues in West Africa 3 1.1.4 Agriculture and Water Use in Togo 3 1.2 Objectives of the Study 4 2. State of the Art 6 2.1 Relevant Agroecosystems, Farming Systems and Irrigation Management in West Africa 6 2.2 Key Performance Indicators: Water productivity and Food Security 8 2.3 Common Approaches Used to Evaluate Crop Water Productivity 9 2.4 Key production Factors: Climate, Soil and Management 9 2.5 Crop Yield Modelling 12 2.6 Integrated Modelling 13 3. Novel Framework for Optimising Irrigation Systems in West Africa 15 3.1 Model-based Sensitivity Analysis of Climate and Management Impact on Crop Water Productivity, Water Demand and Food Security 15 3.2 Experimental Validation of the Farm Model and Management Strategies, Soil Data Analysis and Modelling 17 3.3 Joint Stochastic Analysis of the Impact of Climate and Soil Variability on Crop Water Productivity and Food Security 19 4. Overview of Publications 21 4.1 Potential of Deficit and Supplemental Irrigation under Climate Variability in Northern Togo, West Africa 21 4.2 Impact of Irrigation Strategies on Maize (Zea mays L.) Production in the Savannah Region of Northern Togo (West Africa) 22 4.3 Impact of climate and soil variability on maize (Zea mays L.) yield under full and deficit irrigation in the savannah region of northern Togo, West Africa 23 5. Conclusion and Outlook 26 References 28 A. Selected Publications of the Author 37 A.1 Potential of Deficit and Supplemental Irrigation under Climate Variability in Northern Togo, West Africa 39 A.2 Impact of Irrigation Strategies on Maize (Zea mays L.) Production in the Savannah Region of Northern Togo (West Africa) 61 A.3 Impact of Climate and Soil Variability on Maize (Zea mays L.) Yield under Full and Deficit Irrigation in the Savannah Region of Northern Togo, West Africa 81 B. Histograms of distributions of the expected maize yield in northern Togo (scenarios in the third paper) 121
572

Berichte aus dem Ökolandbau 2022 - Nachwirkungsvermögen von Zwischenfrüchten und organischer Düngung: Einfluss des Zwischenfruchtanbaus auf das Nachwirkungsvermögen organischer Düngemittel beim Anbau von Kartoffeln, Weizen und Mais auf einem Lehmboden im ökologischen Landbau - Ergebnisse aus Feld- und Gefäßversuchen

Müller, Peter, Schliephake, Wilfried 31 January 2022 (has links)
Als Zielstellung wurde in mehrjährigen Gefäß- und Feldversuchen geprüft, welche Wechselwirkungen bei fortgesetztem Zwischenfruchtanbau und organischer Düngung (Kompost, Stalldung, Gülle) auf den Nährstoffumsatz im Boden sowie auf Ertrag und Qualität der nachgebauten Hauptfrüchte sich entwickelt haben. Die Nachwirkung dieser Anbaukombinationen wurden bis zu acht Jahre detailliert dargestellt, da sehr interessante und aktuelle Ergebnisse ermittelt werden konnten. Die Veröffentlichung richtet sich an Einrichtungen zur Beratung und Forschung zum ökologischen Landbau.:1 Einleitung 2 Material und Methoden 2.1 Gefäßversuch 2.2 Feldversuch 2.2.1 Standortbeschreibung 2.2.2 Versuchsaufbau 2.2.3 Versuchsauswertung 2.3 Untersuchungsmethoden 3 Ergebnisse und Diskussion 3.1 Gefäßversuch 3.1.1 Versuchsjahr 2000/2001 3.1.2 Versuchsjahr 2001/2002 3.1.3 Versuchsjahr 2002/2003 3.1.4 Erträge und Nährstoffentzüge im Verlauf der drei Versuchsjahre 3.1.5 Auswirkungen der dreijährigen Versuchsausführung auf den Boden 3.1.6 Schlussfolgerungen zum Gefäßversuch 3.2 Feldversuch 3.2.1 Grundnährstoffgehalte im Boden und Nährstoffentzüge der Hauptfrüchte 3.2.2 Zwischenfruchtanbau und Nmin-Gehalt des Bodens 3.2.3 Erträge der Hauptfrüchte in den einzelnen Untersuchungsjahren 3.2.4 Nährstoffbilanzen 3.2.5 Qualitätsparameter 3.2.6 Schlussfolgerungen zum Feldversuch 4 Fazit 5 Literaturverzeichnis 6 Anhang
573

[en] SCHOOL TIME AND CRIME: INCAPACITATION EFFECTS IN BRAZIL / [pt] TEMPO NA ESCOLA E CRIME: EFEITOS DE INCAPACITAÇÃO NO BRASIL

EDUARDO FAGUNDES DE CARVALHO 29 June 2020 (has links)
[pt] Crimes na adolescência impõem custos não triviais para a sociedade, o que tornou seus determinantes e fatores dissuasivos cada vez mais sujeitos a estudo por economistas. Intervenções no nível da escola são comumente propostas com o objetivo de mitigar o surgimento de carreiras criminais e a perpetuação da violência. Entretanto, as direções e os canais pelos quais as escolas afetam crime podem variar. Esse artigo estuda um deles - os esfeitos de incapacitação - explorando um programa federal que aumentou as horas escolares em escolas públicas brasileiras. Usando variação quasiexperimental na probabilidade de aderir ao programa e dados georreferenciados de crime do estado de São Paulo, é possível estimar os feitos causais do programa em atividade criminal ao redor das escolas. Os resultados sugerem que incapacitação de fato previne jovens de cometerem crimes menos severos, com evidência mais forte para crimes relacionados a drogas e para escolas com alunos mais pobres. / [en] Juvenile crime imposes non-trivial costs to societies, which have made its determinants and deterrents increasingly subject of study by economists. School-based interventions are often proposed in order to mitigate the rise in criminal careers and the perpetuation of violence. However, the directions and channels through which schooling may affect crime vary. This paper studies one of them - namely the incapacitation effects - exploiting a federal program that extended school hours in Brazilian public schools. Using quasiexperimental variation in the probability of receiving the program and georeferenced crime data from the state of São Paulo, it is possible to estimate the causal effect of the program on criminal activity in the surroundings of the schools. Results suggest incapacitation does prevent juvelines from engaging in less offensive crimes, with stronger evidence for drug-related crimes and for schools with poorer students.
574

[en] AN EFFICIENT ALGORITHM FOR THE ADJACENT QUADRATIC SHORTEST PATH PROBLEM WITH APPLICATION TO SMOOTH TRANSMISSION LINE ROUTING / [pt] UM ALGORITMO EFICIENTE PARA O PROBLEMA DE CAMINHO MAIS CURTO QUADRÁTICO ADJACENTE COM APLICAÇÃO NO DESENHO DE ROTAS SUAVES DE LINHAS DE TRANSMISSÃO

JOAO MARCOS DUSI VILELA 13 January 2022 (has links)
[pt] Essa dissertação explora o problema roteamento de linhas de transmissão (LT) através da solução do caminho mais curto em um grafo sem ciclos de melhoria, considerando custos quadráticos para arcos adjacentes. Esse problema é conhecido como o Problema do Caminho Mínimo Quadrático Adjacente (CMQA). Esse trabalho apresenta uma descrição teórica do CMQA, propõe uma extensão do algoritmo Dijkstra (aqDijkstra) para solução de CMQA em tempo polinomial e discute como o algoritimo pode ser utilizado em metodologias de roteamento de LT. Em seguida, apresentamos uma melhoria estendendo o algoritmo A estrela para sua forma adjacente quadrática (aqA estrela), incluindo uma etapa de busca reversa para estimação de custos de chegada. Foram feitos experimentos computacionais contemplando a variação de custos quadráticos, geração de instâncias aleatórias, testes de estresse e comparação com abordagens já utilizadas na literatura. Os resultados sugerem que: (i) aqA estrela teve o melhor desempenho, atingindo tempos de busca 40 vezes mais rápidos que aqDijkstra e 50 vezes mais rápido que a abordagem mais rápida apresentada pela literatura; (ii) a eficiência dos algoritmos não foi afetada pela variação dos custos quadráticos; (iii) os algoritmos propostos aqA estrela e aqDijkstra também foram mais eficientes nas instancias aleatórias, reafirmando a superioridade dos mesmos. Duas aplicações são apresentadas, uma de objetivo ilustrativo e outra para um caso real. O algoritimo aqA estrela foi usado para solução de um CMQA em um grafo de quase um bilhão de arcos quadraticos, resultado em uma rota proposta com custos adicionais três vezes menor. / [en] This dissertation explores the problem of transmission line (TL) routing through finding the shortest path on an undirected graph with no improving cycles, considering quadratic costs for adjacent arcs. This problem is known as the Adjacent Quadratic Shortest Path Problem (AQSPP). This work provides the theoretical background for the AQSPP, proposes an extension of Dijkstra s algorithm (aqDijkstra) for solving AQSPP in polynomial-time and discusses how AQSPP can be included in routing methodologies. Furthermore, it is presented an improvement to the algorithm: the adjacent quadratic A star (aq A star) with a backward search for cost-togo estimation, to speed up search. For computational experiments, aqDijkstra and aqA star are benchmarked with other algorithms from the technical literature. The search behavior of the algorithms is also studied within different tests, including: quadratic cost variation, randomly generated graph instances and increasingly larger instances. The numerical results suggests that: (i) aqA star outperformed all the other algorithms, being 40 times faster than aqDijsktra and 50 times faster than the fastest benchmark algorithm; (ii) the studied algorithms do not lose efficiency as quadratic costs increase; (iii) aqA star and aqDijkstra were faster benchmark algorithms under random graph instances, indicating their robustness. Two applications are provided, one for illustrative purposes, and another to study performance on a real application. The aqA star algorithm solved an AQSSP on a graph with almost a billion quadratic arcs and provided a route with three times lower additional costs.
575

[en] AUTOMATED SYNTHESIS OF OPTIMAL DECISION TREES FOR SMALL COMBINATORIAL OPTIMIZATION PROBLEMS / [pt] SÍNTESE AUTOMATIZADA DE ÁRVORES DE DECISÃO ÓTIMAS PARA PEQUENOS PROBLEMAS DE OTIMIZAÇÃO COMBINATÓRIA

CLEBER OLIVEIRA DAMASCENO 24 August 2021 (has links)
[pt] A análise de complexidade clássica para problemas NP-difíceis é geralmente orientada para cenários de pior caso, considerando apenas o comportamento assintótico. No entanto, existem algoritmos práticos com execução em um tempo razoável para muitos problemas clássicos. Além disso, há evidências que apontam para algoritmos polinomiais no modelo de árvore de decisão linear para resolver esses problemas, embora não muito explorados. Neste trabalho, exploramos esses resultados teóricos anteriores. Mostramos que a solução ótima para problemas combinatórios 0-1 pode ser encontrada reduzindo esses problemas para uma Busca por Vizinho Mais Próximo sobre o conjunto de vértices de Voronoi correspondentes. Utilizamos os hiperplanos que delimitam essas regiões para gerar sistematicamente uma árvore de decisão que repetidamente divide o espaço até que possa separar todas as soluções, garantindo uma resposta ótima. Fazemos experimentos para testar os limites de tamanho para os quais podemos construir essas árvores para os casos do 0-1 knapsack, weighted minimum cut e symmetric traveling salesman. Conseguimos encontrar as árvores desses problemas com tamanhos até 10, 5 e 6, respectivamente. Obtemos também as relações de adjacência completas para os esqueletos dos politopos do knapsack e do traveling salesman até os tamanhos 10 e 7. Nossa abordagem supera consistentemente o método de enumeração e os métodos baseline para o weighted minimum cut e symmetric traveling salesman, fornecendo soluções ótimas em microssegundos. / [en] Classical complexity analysis for NP-hard problems is usually oriented to worst-case scenarios, considering only the asymptotic behavior. However, there are practical algorithms running in a reasonable time for many classic problems. Furthermore, there is evidence pointing towards polynomial algorithms in the linear decision tree model to solve these problems, although not explored much. In this work, we explore previous theoretical results. We show that the optimal solution for 0-1 combinatorial problems can be found by reducing these problems into a Nearest Neighbor Search over the set of corresponding Voronoi vertices. We use the hyperplanes delimiting these regions to systematically generate a decision tree that repeatedly splits the space until it can separate all solutions, guaranteeing an optimal answer. We run experiments to test the size limits for which we can build these trees for the cases of the 0-1 knapsack, weighted minimum cut, and symmetric traveling salesman. We manage to find the trees of these problems with sizes up to 10, 5, and 6, respectively. We also obtain the complete adjacency relations for the skeletons of the knapsack and traveling salesman polytopes up to size 10 and 7. Our approach consistently outperforms the enumeration method and the baseline methods for the weighted minimum cut and symmetric traveling salesman, providing optimal solutions within microseconds.
576

Assessment of Benthic Macroinvertebrate Community Impairment from High-Aluminum Acid Mine Drainage in Middleton Run, Ohio, USA and the Impact of Ingested Aluminum on Crayfish Growth

Hellyer, William N. 24 September 2014 (has links)
No description available.
577

The Recovery of an AMD-impacted Stream Treated by Steel Slag Leach Beds: A Case Study in the East Branch of Raccoon Creek, Ohio

Hawkins, Caleb M. 24 August 2015 (has links)
No description available.
578

Pediatric Cochlear Implant Outcomes in Auditory Neuropathy/Auditory Dys-Synchrony

Eby, Christine A. 07 July 2004 (has links)
No description available.
579

[pt] CONHECIMENTOS CURRICULARES E VISÕES DE DOCÊNCIA NA FORMAÇÃO DE PROFESSORES PARA AS ESCOLAS DE TEMPO INTEGRAL: EM FOCO OS CURSOS DE ESPECIALIZAÇÃO EM EDUCAÇÃO INTEGRAL / [en] CURRICULAR KNOWLEDGE AND VISIONS OF TEACHING IN TEACHER TRAINING FOR FULL-TIME SCHOOLS: IN FOCUS THE COURSES OF SPECIALIZATION IN INTEGRAL EDUCATION

LUISA FIGUEIREDO DO AMARAL E SILVA 18 December 2019 (has links)
[pt] Esta tese teve como tema a formação docente sobre as temáticas da educação integral e do tempo integral e como objeto os cursos de especialização em Educação Integral e Integrada, oferecidos por universidades públicas brasileiras, por meio do Programa Mais Educação (PME). O principal objetivo foi a análise dos conhecimentos curriculares que compuseram os cursos de especialização em educação integral e dos sentidos assumidos sobre a docência em escolas de tempo integral. Como objetivos específicos, procurou: (1) compreender o processo de elaboração e desenvolvimento curricular das especializações; (2) analisar as possíveis relações entre os conhecimentos curriculares e os sentidos de docência identificados e (3) identificar e refletir sobre os conhecimentos docentes que possam emergir desta relação. Teoricamente, as análises foram construídas a partir do diálogo com diferentes autores, como Tardif (2013), Nóvoa (1997), Branco (2012), Cavaliere (2007, 2009), Coelho (2002, 2009), Veloso (2009), Silva (2011), Sacristán (2007, 2017), Schulman (2014), entre outros, que ajudaram a compreender melhor os fenômenos pesquisados. Metodologicamente, esta tese se baseia na pesquisa qualitativa (MINAYO, 2004), a fim de conhecer melhor os sentidos e intencionalidades que constituíram os cursos. A partir desta orientação qualitativa, esta pesquisa realizou um estudo de caso coletivo (ALVEZ-MAZZOTTI, 2006; YIN, 2001; ANDRÉ, 2013), em quatro especializações desenvolvidas nas regiões sul, sudeste e centro-oeste. A fim de coletar os dados de pesquisa, foram realizadas: (1) entrevistas semiestruturadas com coordenadores; (2) questionários com professores e (3) pesquisa documental. Diante dos dados coletados, as análises das entrevistas e questionários foram realizadas com base na análise de conteúdo (BARDIN, 1977) e os documentos pedagógicos com base na análise documental (LÜDKE; ANDRÉ, 2012; OLIVEIRA, 2007). Por fim, na 8 intenção de aprofundar e responder as últimas questões e objetivos desta tese, foi realizada a triangulação de dados (MINAYO et al., 2012; YIN, 2001). Assim, de posse dessas diferentes escolhas e dos caminhos trilhados a partir delas, esta pesquisa evidenciou como resultado a existência de diferentes conhecimentos curriculares e visões de docência nos cursos pesquisados. Os mesmos foram organizados em diferentes categorias e subcategorias; que ora se apresentaram distantes dos temas das especializações e ora se aproximaram desses temas, indicando a existência de conhecimentos e docências específicos às escolas de tempo integral. Em sua conclusão, evidenciou que, se por um lado esses cursos apresentaram diferentes problemáticas e desafios relacionados ao PME e a estrutura das universidades e suas capacidades para atender a essa demanda do MEC; por outro representaram experiências interessantes e relevantes para a análise sobre os conhecimentos docentes (SHULMAN, 2014) e os processos de profissionalização docente (NÓVOA, 2016; TARDIF, 2013) desenvolvidos por meio da formação de professores para, com e nas escolas de tempo integral. / [en] This thesis had as its theme the teacher education on the themes of integral and full-time education and as object the specialization courses in Integral and Integrated Education, offered by Brazilian public universities, through Programa Mais Educação (PME). The aim was the analysis of the curricular knowledge that composed the courses of specialization in integral education and of the senses assumed on the teaching in full-time schools. As objectives, it seeks to: (1) understand the process of curriculum development and development of specializations; (2) to analyze the possible relationships between curricular knowledge and the teaching senses identified and (3) to identify and reflect on the teaching knowledge that may emerge from this relationº Theoretically, the analyzes were constructed from the dialogue with different authors, such as Tardif (2013), Nóvoa (1997), Branco (2012), Cavaliere (2007, 2009), Coelho (2002, 2009), Veloso (2009), Silva (2011), Sacristán (2007, 2017), Schulman (2014), among others, that helped to better understand the phenomena researched. Methodologically, this thesis is based on qualitative research (MINAYO, 2004), in order to better understand the meanings and intentionalities that constituted the courses. From this qualitative orientation, this research carried out a collective case study (ALVEZ-MAZZOTTI, 2006; YIN, 2001; ANDRÉ, 2013), in four specializations developed in the south, southeast and center-west regions. In order to collect the research data, we performed: (1) semi-structured interviews with coordinators; (2) questionnaires with teachers and (3) documentary research. According to the data collected, interviews and questionnaires were analyzed based on content analysis (BARDIN 1977) and pedagogical documents based on documentary analysis (LÜDKE; ANDRÉ, 2012; OLIVEIRA, 2007). Finally, in order to deepen and answer the last questions and objectives of this thesis, the triangulation of data was done (MINAYO et al., 2012; YIN, 2001). Thus, having these different choices and the paths taken from them, this research evidenced as a result the existence of different curricular knowledge and visions of teaching in the courses studied. They were organized into different categories and subcategories; who now presented themselves far from the themes of specializations and now approached these themes, indicating the existence of specific knowledge and teaching to full-time schools. In its conclusion, it shows that if, on the one hand, these courses presented different problems and challenges related to the PME and the structure of the universities and their capacities to meet this demand of the MEC; on the other, they represented interesting and relevant experiences for the analysis of teachers knowledge (SHULMAN, 2014) and the processes of teacher professionalization (NÓVOA, 2016; TARDIF, 2013) developed through teacher training for, with and in full-time schools.
580

[en] 1-BIT QUANTIZATION APPLIED TO CONTINUOUS PHASE MODULATION / [pt] QUANTIZAÇÃO DE 1-BIT APLICADA A SISTEMAS DE MODULAÇÃO DE FASE CONTÍNUA

RODRIGO ROLIM MENDES DE ALENCAR 19 November 2020 (has links)
[pt] Eficiência energética e espectral são características importantes para comunicações militares e internet das coisas (IoT). Nesta tese, métodos e sistemas de quantização de 1-bit com modulação de fase contínua (CPM) são estudados e propostos para resolver as necessidades de sistemas de comunicações modernos com baixo consumo energético. Nesse contexto, o método de superamostragem em relação a duração de um símbolo é promissor, pois a informação está contida ao longo da transição de fase de sinais CPM, que não são estritamente limitados em banda. Consequentemente, a perda de taxa alcançável causada pela quantização de 1-bit pode ser reduzida consideravelmente, até mesmo para esquemas com maior ordem de modulação. Este estudo investiga diferentes abordagens para melhorar o desempenho do modelo de sistema proposto. Um esquema de codificação de canal é projetado com mapeamento de bits adaptado ao problema de quantização grosseira, fazendo uso de um soft-in soft-out (SISO) turbo receiver. Formas de onda CPM com duração de símbolo significamente menor que o inverso da banda do sinal são propostas, nomeadas de faster-than-Nyquist CPM. Um fator maior de superamostragem é aplicado com uma estratégia de seleção de amostras em um modelo de amostragem adaptativa. Finalmente, resultados numéricos confirmam melhor desempenho em taxa de erro de bit, eficiência espectral e taxa alcançável para os métodos propostos, em comparação às técnicas recentemente utilizadas. / [en] Energy and spectral efficiency are appealing features for military communications and internet of things (IoT). On this thesis, systems and schemes with 1-bit quantization and continuous phase modulation (CPM) are studied and proposed to address the needs for modern and power efficient communications. In this context, oversampling with respect to the symbol duration is promising because the information is conveyed in the phase transitions of the CPM signals, which are not strictly bandlimited. With this, the loss in achievable rate caused by the coarse quantization can be greatly reduced, even for higher order modulation schemes. This study investigates different approaches to enhancing the performance of the proposed system model. A channel coding scheme is designed with a tailored bit mapping, by means of employing a soft-in soft-out (SISO) turbo receiver. CPM waveforms with symbol durations significantly shorter than the inverse of the signal bandwidth are proposed, termed faster-than-Nyquist CPM. Higher oversampling is applied with a sample selection strategy for a nonuniform adaptive oversampling model. Finally, numerical results confirm better performance on bit error rate, spectral efficiency and achievable rate for the proposed methods in comparison with state of the art techniques.

Page generated in 0.0748 seconds