Generation by generation, wireless communication has advanced in various ways and provided reliable communication services at higher and higher data rates to the needs of more and more advanced wireless applications. Two main issues towards future wireless communications are high-speed transmission technique to provide high data rate services and reliable communication to ensure the required performance. This dissertation focuses on these two issues. Since orthogonal frequency division multiplexing (OFDM) has emerged as an enabling technique for high-speed transmission in dispersive environments, major and fundamental issues in OFDM, namely, synchronization, channel estimation, and peak-to-average power ratio (PAPR) reduction are addressed. For the required reliability, automatic repeat request (ARQ) schemes must be applied. Due to large potential performance improvement, adaptive ARQ schemes have recently attracted much attention and are also addressed here. We propose two improved OFDM timing synchronization methods which overcome the drawbacks of existing methods. We present a time-domain-based OFDM channel estimation which outperforms the existing time-domain-based approach and has a similar performance to the linear minimum mean square error estimator but with less complexity. For OFDM systems with transmit diversity, we present a reduced complexity channel estimation which has a comparable performance to the existing method for channels with relatively small delay spreads, but achieves much complexity saving. An approach to find the number of most significant channel taps is described for diverse channel environments. We analyze the effect of non-sample-spaced channel path on the channel estimation and propose a modification for further improvement. Timing synchronization, frequency synchronization and channel estimation are usually addressed separately. Since they can affect each other, the idea of jointly addressing all of them together is much desirable and pursued here. This joint approach reflects the actual performance and gives an opportunity to exploit some information obtained from one task in another, hence promising more improvement. The proposed training preamble-based joint timing and frequency synchronization utilizes some information from the channel estimation. The sync detection is also considered. We design the training symbol to achieve a better coarse timing synchronization. Methods to suppress or circumvent the interference in the frequency estimation caused by timing errors are presented. A new performance measure for OFDM timing synchronization is proposed which leads to obtaining optimal timing estimation setting. Next, we present a joint timing synchronization, frequency synchronization and channel estimation based on training preamble based maximum likelihood realization. Further complexity reduction by an adaptive scheme is also proposed. We address some fundamental questions on peak factors, sampling theorem and sampling series. We present several bounds of bandlimited functions and peak factor ratio bound of a continuous signal and its sampled signal. Some discussion on the requirements of sampling theorems and related aspects on sampling series are presented. We study PAPR behavior of some Reed-Muller codes in OFDM systems in an attempt to find a code with good error correction, low PAPR, efficient encoding/decoding and reasonable code rate. Some regularities of the second and third-order cosets of first order Reed-Muller codes with low PAPR are presented which indicates possibility of finding such code for OFDM. The main issues in adaptive ARQ schemes are how to design the adaptive system parameters and how to effectively sense the channel conditions. We present an approach for designing the adaptive ARQ system parameters based on the through put calculation and optimization. An alternative approach which avoids the tedious throughput calculation is also presented. An effective channel sensing algorithm which utilizes the error correcting capability is proposed. Incorporation of the adaptive frequency hopping concept into the ARQ scheme with adaptive error control is introduced which has a significant throughput improvement in slow fading channels. / Graduate

A SOA está se tornando uma abordagem difundida no desenvolvimento de sistemas. Em sistemas maiores onde se utiliza SOA pode ocorrer problemas de alta demanda, que podem ser resolvidos com arquiteturas distribuídas como clusters. Esta dissertação apresenta a proposta de uma nova arquitetura para distribuição de requisições em clusters de web services. A arquitetura proposta tem foco na distribuição flexível de requisições, possibilitando o emprego de políticas diversificadas, estas voltadas a diferentes objetivos, aplicações e plataformas. A arquitetura também propõe trabalhar de forma dinâmica, possibilitando decisões baseadas na coleta de estado dos elementos que compõem a estrutura de atendimento. A transparência, do ponto de vista do cliente, também é tratada na arquitetura. Os testes da arquitetura foram realizados através de um protótipo que a implementa. O protótipo instancia os objetivos propostos na arquitetura, apresentando ganhos de desempenho em relação à solução existente atualmente. A flexibilidade das políticas de distribuição é destacada através da construção de uma política, cujo objetivo é melhorar a eficiência no consumo de energia de clusters. Dentre as contribuições do trabalho está a criação de uma nova arquitetura de software que atua como facilitadora para a criação de políticas de distribuição de requisições mais eficiente para web services / SOA is becoming a widespread approach to develop systems. High demand problems may appear in huge systems where SOA and web services are used. This problems can be solved by means of distributed architectures like clusters. This work presents the proposal of a new architecture for request distribution in web service clusters. The proposed architecture provides flexible request distribution. It allows the use of several policies, these related to different objectives, applications and platforms. The architecture\'s dynamic feature enables decisions based on states of the cluster\'s elements, in a transparent way, under clients\' point of view. The architecture was tested using a prototype that implements the proposed ideas in this work. The objectives of the proposal were reached by the prototype and still shown performance improving in many cases, when comparing to an existing solution. The use of a novel policy, related to energetic efficiency for clusters, is also shown on the experiments related to flexibility. Among architecture\'s contributions is a novel software architecture that acts as a facility to create and to test more efficient web services policies

The aim of diploma thesis is to suggest a methodology how can praxis detect their requests for technical standards. In the thesis is also used questionare. The purpose is to find out why organizations use or do not use technical standards, if they use also supportive technical standards. Which ares would organization prefere for supportive technical standards and how much are the able to pay for them.

No abstract available. / Dissertation (LLM)--University of Pretoria, 2012. / gm2014 / Centre for Human Rights / unrestricted

in English: The Expression of Plea, Request and Order in Spanish (with Regard to Czech) The aim of this work is to examine the language forms for expressing a plea, request and order in Spanish, taking into account their Czech counterparts. The work is divided into theoretical and practical part. In the theoretical part of the work we start from the basic works that gave rise to the modern theory of politeness. These findings then serve as a pragmatic basis for the study of our selected structures. For analysis we choose: imperative, deontic use of infinitive and gerund, deontic use of paradigms hablaré and hablo, performative use of verbs mandar and ordenar, performative use of verbs pedir, rogar and suplicar, interrogative constructions with verb poder, interrogative constructions with por qué no, interrogative constructions with quieres and interrogative constructions with te importa / importaría que. We theoretically describe these constructions and then analyze them on the Intercorp v12 corpus and present their Czech counterparts. Our intention is a qualitative analysis, with special emphasis on the context in which the structure is located.

The present study evaluated telehealth training with parents on techniques for working with their children with autism spectrum disorder in Southeastern Europe. The purpose of this study was to research the effects of telehealth training on the parents and the increase of mands on the children. The participants of this study included three mothers and three children, which totaled six participants. Parents were trained on how to increase functional communication in their child. Telehealth training was based on an effective training package called Behavior Skills Training (BST). BST consist of instructions, modeling, rehearsal, and feedback. The resources needed for the training were minimal. They included access to internet, a device installed with a camera, and the children’s preferred items which were placed within view but outside the reach of the child. Sessions were recorded where parents interacted with their child during the generalization sessions as well as during the role plays with the trainer. The videos were observed in order to collect frequency data, determine if parents completed each step of the training, and if the child manded during each session. All three parent participants reported an increase in manding from their child, better communication skills between them and their child, and an increase in self-efficacy. These results suggest that countries in South-Eastern Europe should seek to implement telehealth training, mand training, and parent training as a program that not only these families may benefit from, but also the entire community. Future research should be conducted with a larger sample size and with more trainers using telehealth as an effective tool to increase better communication and decrease problem behaviors.

Noncompliance in students with Emotional/Behavioral Disorders (EBD) can contribute to difficulty with peer and teacher relationships and may result in reduced time for academic instruction. The Precision Request, an intervention which uses alpha commands, verbal praise, and reductive consequences, has been shown to increase compliance in students with EBD, but no studies have accounted for which component is responsible for the change. This study used an ABCDAX add-in component analysis to determine which component of the Precision Request produced the most effect on behavioral compliance in five sixth-grade elementary students with EBD. Data were collected on percent of student compliance, latency to compliance, and teacher and paraprofessional use of verbal praise and reductive consequences. Percent of correct implementation of the Precision Request was also recorded. All data were subsequently inspected via visual analysis. The interventionists which participated in the study were unable to implement the Precision Request with fidelity and no effect was found on student compliance, which prompted researchers to examine characteristics of the interventionists as a possible explanation for failure to implement with fidelity. A comparison of interventionists suggests that the Precision Request may be too difficult to implement for an individual who lacks behavioral training, who does not use foundational classroom procedures such as positive reinforcement and verbal praise, and/or whose philosophical viewpoints are not conducive to behavior analysis. Future research should examine contextual fit as regards behavioral interventions and interventionists, as well as which behavioral principles need to be mastered by an interventionist before the Precision Request can be implemented with fidelity.

No description available.

No description available.

No description available.