The purpose of this thesis is to demonstrate the effects of mismatch errors that occur in time-interleaved analog-to-digital converters (TI-ADC) and how these are compensated for by proprietary methods from Signal Processing Devices Sweden AB. This will be demonstrated by two different implementations, both based on the combined digitizer/generator SDR14. These demonstrations shall be done in a way that is easy to grasp for people with limited knowledge in signal processing. The first implementation is an analog video demo where an analog video signal is sampled by such an TI-ADC in the SDR14, and then converted back to analog and displayed with the help of a TV tuner. The mismatch compensation can be turned on and off and the difference on the resulting video image is clearly visible. The second implementation is a digital communication demo based on W-CDMA, implemented on the FPGA of the SDR14. Four parallel W-CDMA signals of 5 MHz are sent and received by the SDR14. QPSK, 16-QAM, and 64-QAM modulated signals were successfully sent and the mismatch effects were clearly visible in the constellation diagrams. Techniques used are, for example: root-raised cosine pulse shaping, RF modulation, carrier recovery, and timing recovery.

The recent advance in Field Programmable Gate Array (FPGA) technology has been largely embraced by the communication industry, which views this technology as an effective and economical alternative to the design of Application Specific Integrated Circuits (ASICs). The primary reasons for switching to FPGAs are lower development and non-recurring engineering costs, the flexibility to design to a preliminary standard and adapt the design as the standard evolves, as well as the option of performing software updates in the field.<p> A sector with strong interest in FPGAs is the coaxial cable TV/Internet distribution industry. The creation of soft preliminary standards by the standards organization governing the industry has been the main catalyst for the massive adoption of FPGAs by small to medium size companies, which see this technology as an opportunity to compete in this open market.<p> Both the circuit speed and the economy of FPGA technology depend upon using algorithms that map efficiently into its fabric. Often it is prudent to sacrifice performance to improve either clock speed or economy when developing with FPGAs. The purpose of this research is to both revise and devise synchronization algorithms / structures for cable digital receivers that are to be implemented in FPGA. <p> The main communication scheme used by the coaxial cable distribution industry is digital Quadrature Amplitude Modulation (QAM). The problem of synchronizing to the QAM signal in the receiver is not a new topic and several synchronization-related circuits, which were devised with ASICs implementation in mind, can be found in the open literature. Of interest in this thesis is the non-data-aided digital timing synchronizer that was proposed by D'Andrea to recover timing with no knowledge of the transmitted data. Accurate timing estimation was achieved by reshaping the received signal with a prefilter prior to estimating the timing. <p> A problem with D'Andrea's synchronizer is that the prefilter for reshaping the signal is a relatively long Finite Impulse Response (FIR) filter, whose implementation requires a large number of multipliers. This may not have been an issue with ASICs in as much as the number of hardwired multipliers on a chip is not limited as it is in an FPGA chip. One contribution in this research is to propose an alternative to D'Andrea's synchronizer by replacing the long FIR filter with two single-pole Infinite Impulse Response (IIR) filters that are directly placed inside the timing recovery loop. This novel architecture, which drastically reduces the number of multipliers, is well suited for FPGA implementation.<p> Non-data-aided feedforward synchronizers, which use the same prefilter as D'Andrea's synchronizer, have been receiving significant attention in recent years. Detailed performance analysis for these synchronizers can be found in the open literature. These synchronizers have the advantage of using a feedfordward structure rather than a feedback structure, as it is the case in D'Andrea's synchronizer, to estimate the timing. While D'Andrea's synchronizer has an advantage in performance over a non-data-aided feedforward synchronizer, this has not been reported in the literature. In this thesis a second contribution consists of thoroughly analyzing the steady state timing jitter in D'Andrea synchronizer by deriving a closed-form expression for the noise power spectrum and a simple equation to estimate the timing jitter variance. <p> A third contribution is a novel low-complexity and fast acquisition coherent detector for the detection of Quadrature Phase Shift Keying (QPSK) (i.e., 4-QAM) symbols. This detector performs carrier phase synchronization much faster than a conventional coherent detector. The acquisition time is comparable to that of a differential detector. The fast acquisition comes at the expense of phase jitter, and the end result is a 1 dB performance loss over theoretical coherent detection. This detector can be used in place of the differential detector with no economic penalty. Doing so yields a performance advantage of about 2 dB over differential detection.

This thesis explores how digital communication can support compassionate leaders and compassionate workplaces. Through grounded theory methods, exploration and understanding emerged from compassionate leader semi-structured interviews. Emergent themes maintain digital communication can support the evolution of compassionate workplace connectedness and collaboration leading to a compassionate workplace experience. Compassionate leaders stimulating workplace compassion build an atmosphere of trust culminating in increased productivity and a joyful culture where one-on-one to multi-way interaction is supported by digital communication tools.

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Este trabalho consiste no estudo sobre como a inclusão de ferramentas de comunicação digital nas organizações pode influir na cultura e na comunicação. A ênfase recai na investigação de como a utilização do Correio Eletrônico, da Intranet e das Listas de Discussão podem modificar o processo de comunicação organizacional através da criação de novas práticas culturais que possibilitam a participação dos funcionários no processo comunicativo. A análise resgata o modo como essas ferramentas foram implantadas, a sua apropriação pelos membros organizacionais e as práticas culturais que foram geradas a partir do seu uso. Para isso, realizou-se um estudo de caso na Companhia de Processamento de Dados do Rio Grande do Sul (Procergs). O estudo contempla o relato dos funcionários da organização que utilizam essas ferramentas diariamente nas rotinas de trabalho. Por meio da fala dos participantes, constatou-se que essas ferramentas proporcionam maior envolvimento desses funcionários no processo de comunicação. Entretanto, elas não horizontalizam a relação existente entre os funcionários e a organização, que permanece sendo o espaço de conexão do relacionamento comunicacional. / This master thesis addresses the inclusion of digital communication tools in organizations and how it affects their culture and communication habits. The focus is on how the adoption of Electronic Mail, Intranet and Discussion Lists may change the processes of organizational communication by creating new cultural conventions that enable employees to participate in the communicative process. A case study at Companhia de Processamento de Dados do Rio Grande do Sul (Procergs) were conducted to evaluate how these tools were adopted, how the staff assimilated them and what cultural conventions were created by their use. This case study collected various reports given by staff members who use these tools on the daily work routine. The interviews demonstrated that digital communication tools allow a better involvement of the employees in the communication process. However, the tools by themselves do not equalize the relationship between the organization and its employees, which remains as the connecting space to communicative interaction.

Este trabalho consiste no estudo sobre como a inclusão de ferramentas de comunicação digital nas organizações pode influir na cultura e na comunicação. A ênfase recai na investigação de como a utilização do Correio Eletrônico, da Intranet e das Listas de Discussão podem modificar o processo de comunicação organizacional através da criação de novas práticas culturais que possibilitam a participação dos funcionários no processo comunicativo. A análise resgata o modo como essas ferramentas foram implantadas, a sua apropriação pelos membros organizacionais e as práticas culturais que foram geradas a partir do seu uso. Para isso, realizou-se um estudo de caso na Companhia de Processamento de Dados do Rio Grande do Sul (Procergs). O estudo contempla o relato dos funcionários da organização que utilizam essas ferramentas diariamente nas rotinas de trabalho. Por meio da fala dos participantes, constatou-se que essas ferramentas proporcionam maior envolvimento desses funcionários no processo de comunicação. Entretanto, elas não horizontalizam a relação existente entre os funcionários e a organização, que permanece sendo o espaço de conexão do relacionamento comunicacional. / This master thesis addresses the inclusion of digital communication tools in organizations and how it affects their culture and communication habits. The focus is on how the adoption of Electronic Mail, Intranet and Discussion Lists may change the processes of organizational communication by creating new cultural conventions that enable employees to participate in the communicative process. A case study at Companhia de Processamento de Dados do Rio Grande do Sul (Procergs) were conducted to evaluate how these tools were adopted, how the staff assimilated them and what cultural conventions were created by their use. This case study collected various reports given by staff members who use these tools on the daily work routine. The interviews demonstrated that digital communication tools allow a better involvement of the employees in the communication process. However, the tools by themselves do not equalize the relationship between the organization and its employees, which remains as the connecting space to communicative interaction.

As redes sociais virtuais são um meio de comunicação que se diferencia da mídia tradicional por uma razão fundamental: a distribuição entre os usuários da capacidade de comunicar. O usuário dessas redes não se limita à posição de espectador, pois ele pode ser também autor, produtor e promotor de textos ou outros materiais. Cai, portanto, o modelo top-down unidirecional, e ganha espaço uma comunicação bidirecional (entre usuários) e difusa, o que representa a transição de uma topologia de árvore para outra, oposta, de rizoma. O objetivo deste trabalho é compreender a comunicação nas redes sociais virtuais, o que será feito analisando-as externa e internamente. Visa-se a formar, dessa maneira, um construto sobre essas redes quanto à sua técnica e seus usuários, sua forma e suas identidades, o que delas irradia e nelas se desenvolve, e, assim, precisar as características fundamentais da comunicação nesses espaços. / Virtual social networks are a means of communication that differs from traditional media due to one fundamental reason: the power to communicate is distributed among their users. In these networks, the user is not merely the spectator, but also the author, the producer, and the promoter of texts or other materials. Therefore, these networks put aside the unidirectional top-down model, giving ground to the emergence of a bidirectional and diffuse communication, which represents a topological transition from tree to rhizome. This research looks for understanding the communication in virtual social networks by analyzing them internally and externally. It seeks building a construct on these networks\' technique and users, their shape and identities, what irradiates from them and what grows in them, thus allowing the understanding of the fundamental communication characteristics in these spaces.

Este trabalho consiste no estudo sobre como a inclusão de ferramentas de comunicação digital nas organizações pode influir na cultura e na comunicação. A ênfase recai na investigação de como a utilização do Correio Eletrônico, da Intranet e das Listas de Discussão podem modificar o processo de comunicação organizacional através da criação de novas práticas culturais que possibilitam a participação dos funcionários no processo comunicativo. A análise resgata o modo como essas ferramentas foram implantadas, a sua apropriação pelos membros organizacionais e as práticas culturais que foram geradas a partir do seu uso. Para isso, realizou-se um estudo de caso na Companhia de Processamento de Dados do Rio Grande do Sul (Procergs). O estudo contempla o relato dos funcionários da organização que utilizam essas ferramentas diariamente nas rotinas de trabalho. Por meio da fala dos participantes, constatou-se que essas ferramentas proporcionam maior envolvimento desses funcionários no processo de comunicação. Entretanto, elas não horizontalizam a relação existente entre os funcionários e a organização, que permanece sendo o espaço de conexão do relacionamento comunicacional. / This master thesis addresses the inclusion of digital communication tools in organizations and how it affects their culture and communication habits. The focus is on how the adoption of Electronic Mail, Intranet and Discussion Lists may change the processes of organizational communication by creating new cultural conventions that enable employees to participate in the communicative process. A case study at Companhia de Processamento de Dados do Rio Grande do Sul (Procergs) were conducted to evaluate how these tools were adopted, how the staff assimilated them and what cultural conventions were created by their use. This case study collected various reports given by staff members who use these tools on the daily work routine. The interviews demonstrated that digital communication tools allow a better involvement of the employees in the communication process. However, the tools by themselves do not equalize the relationship between the organization and its employees, which remains as the connecting space to communicative interaction.

Orientador: Sergio Ferreira do Amaral / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Educação / Made available in DSpace on 2018-08-04T22:12:46Z (GMT). No. of bitstreams: 1 Antonio_LilianedeQueiroz_D.pdf: 317889 bytes, checksum: ed8ce5e1914c4a0e1985bb14a611dd79 (MD5) Previous issue date: 2005 / Resumo: No presente trabalho foi analisado o impacto que um ambiente virtual interativo venha a ter sobre um grupo de professores, por meio de suas manifestações de comunicação e de interatividade bem como a cooperação e a colaboração que um ambiente virtual interativo apresentado como um ferramental pedagógico nas capacitações de professores. O ambiente virtual interativo foi disponibilizado aos assistentes técnicos pedagógicos e aos supervisores de Ensino da Rede Estadual de Educação de São Paulo. Seu eixo central foi o conteúdo de Ensino Religioso que, enquanto necessidade de capacitação para os professores, pode ser discutido e criticado. Foram sugeridas também ações e citações pedagógicas, de forma a realizar a teoria e a prática, a fim de que os alunos de sétimas e oitavas séries do Ensino Fundamental pudessem desenvolver o conceito de Ensino Religioso de maneira pedagógica, sendo construída pelos professores multiplicadores, havendo, assim, uma maior proximidade deles com a sua realidade / Abstract: In current research it was analyzed the impact of a virtual interactive environment over a selected group of professors taking it account not only their behavior of communication and interactivity but also the cooperation and collaboration that the proposed virtual interactive environment would have as a pedagogical tool . The virtual interactive environment was made available to the pedagogical technical assistants and to the teaching supervisors of the State Education Agencies of São Paulo. Its main subject was based on religious teaching that could be used for both professors training and debating. Furthermore, it was suggested pedagogical activities in order to join theory and practice directed to students of 7th and 8th grades. It was expected that this students would develop religious concepts in a pedagogical point of view supported by professors that could assure a closed connection to the reality / Doutorado / Educação, Ciencia e Tecnologia / Doutor em Educação

Orientador: Jaime Portugheis / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-15T19:30:44Z (GMT). No. of bitstreams: 1 Andrade_Alexandrede_D.pdf: 5191552 bytes, checksum: ae675c28ea93ab3a91655042f4cd13d1 (MD5) Previous issue date: 2010 / Resumo: Esta tese aborda métodos de estimação probabilística em sistemas de comunicações usando a teoria de grafos-fatores e seu algoritmo genérico soma-produto. Estas ferramentas são atualmente reconhecidas como um ambiente ideal para derivar vários esquemas de decodificação/ estimação, e também integrar modelos de componentes típicos num sistema de comunicação para melhor desempenho do processo de recepção. Mais genericamente, são adequadas para projetos de receptores unificados. Além disso, vários esquemas de decodificação conjunta fonte/canal podem ser contextualizados neste ambiente. Partimos de uma revisão geral da teoria grafos-fatores e do algoritmo soma-produto de forma abrangente e inserindo os fundamentos matemáticos relacionados. Na sequência aplicamos estes conceitos a sistemas de comunicações. Focamos em sistemas de grafos com ciclos, que são de grande interesse e que resultam na versão iterativa do algoritmo somaproduto, onde cronogramas de execução devem ser arbitrados eficientemente. Descrevemos a decodificação turbo seguindo esquemas de grafos-fatores normais e causais, a forma mais apropriada para a descrição e análise de cronogramas. A partir desta formulação, estudamos o caso da decodificação turbo na sua variante não-bloco, com entrelaçadores periódicos e decodificação contínua/causal. Apresentamos um cronograma completo do algoritmo soma-produto para este caso, mostrando vantagens práticas em relação ao proposto na literatura, sobretudo em relação a sua implementação. Na última parte da tese, apresentamos um estudo da aplicação de grafos-fatores no problema de decodificação iterativa conjunta fonte/canal. Partimos de um modelo genérico de fonte com memória, discreta no tempo e contínua em amplitude, consideramos quantização vetorial e tratamos o problema da decodificação iterativa conjunta integrando modelos destes componentes com o resto do sistema. Alguns resultados de simulações computacionais para os esquemas propostos são apresentados / Abstract: The present thesis deals with probabilistic inference methods for communication systems described by the unifying framework of factor graphs and the general elimination algorithm, the so called sum-product algorithm. These exceedingly general tools are understood as a state of the art environment to build many decoding schemes, and to model typical components for a joint efficient inference at reception. More generally, is a suitable framework to unified receiver designs. Additionally, some joint source channel decoding schemes can also be proper modeled under this context. We start with a review of this framework and related mathematical topics. Thereafter, we particularize to cases of interest, like typical communication systems. This framework gives powerful insights into the structures of multivariate constrained systems and shows how distributed probabilistic inferences can be performed, as shown for typical communication systems with a standard channel encoder. Systems represented by fator graphs with cycles are the most relevant. For the iterative version of the sum-product algorithm, a calculation schedule has to be efficiently chosen. We review the turbo decoding scheme for the classical turbo code using a normal and causal factor graph realization, providing an environment for scheduling descriptions. Then, we approach the non-block turbo decoding version (stream-oriented turbo codes), where general periodic and causal interleavers can be used and continuous decoding schemes are required. We present a full decoding sum-product schedule for this case, with pratical improvements over the usual non-graphical decoding scheme. In the last part of this thesis, we address the joint source channel decoding problem using the factor-graph framework. Starting from a general source model, linear discrete time series, we consider straight vectorial quantization. Instead of trying to remove redundancy, we go in the direction of building decoding schemes that explore this redundancy from source model and quantizer map.We analyse cases when iterative decoding can be performed taking these elements into account in a proper way. Some simulation on the proposed schemes are presented / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica