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  • 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.
21

RIPCom – A REMOTE INTERNET PROTOCOL COMMUNICATION SYSTEM

Lawson, Shawn, Brentzel, Kelvin, Harris, Carol, Coronado, Patrick, Pasciuto, Michael, Greenfield, Paul, Zajkowski, Thomas 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / NASA Goddard Space Flight Center (GSFC) is developing the Remote Internet Protocol Communication (RIPCom) system, which is a wireless communication system that makes an aircraft look like a network node in the sky. RIPCom provides an Ethernet to Radio Frequency (RF) connection solution for real-time data transmission, and its design allows the end points of the communication system to become nodes on a network with assigned IP addresses. RIPCom’s design is especially suitable for Unmanned Aerial Vehicle (UAV) applications, and its versatility makes it valuable for many systems that require a high speed, digital wireless network.
22

A conceptual system design and managerial complexity competency model

Amaechi, Austin Oguejiofor January 2013 (has links)
Complex adaptive systems are usually difficult to design and control. There are several particular methods for coping with complexity, but there is no general approach to build complex adaptive systems. The challenges of designing complex adaptive systems in a highly dynamic world drive the need for anticipatory capacity within engineering organizations, with a goal of enabling the design of systems that can cope with an unpredictable environment. This thesis explores this question of enhancing anticipatory capacity through the study of a complex adaptive system design methodology and complexity management competencies. A general introduction to challenges and issues in complex adaptive systems design is given, since a good understanding of the industrial context is considered necessary in order to avoid oversimplification of the problem, neglecting certain important factors and being unaware of important influences and relationships. In addition, a general introduction to complex thinking is given, since designing complex adaptive systems requires a non-classical thought, while practical notions of complexity theory and design are put forward. Building on these, the research proposes a Complex Systems Life-Cycle Understanding and Design (CXLUD) methodology to aid system architects and engineers in the design and control of complex adaptive systems. Starting from a creative anticipation construct - a loosening mechanism to allow for more options to be considered, the methodology proposes a conceptual framework and a series of stages to follow to find proper mechanisms that will promote elements to desired solutions by actively interacting among themselves. To illustrate the methodology, a financial systemic risks infrastructure systems architecture development case study is presented. The final part of this thesis develops a conceptual model to analyse managerial complexity competency model from a qualitative phenomenological study perspective. The model developed in this research is called Understanding-Perception-Action (UPA) managerial complexity competency model. The results of this competency model can be used to help ease project manager’s transition into complex adaptive projects, as well as serve as a foundation to launch qualitative and quantitative research into this area of project complexity management.
23

Communication gouvernementale avec les médias en cas de crise / Communication between government and media in crisis management

Liu, Xin 21 September 2012 (has links)
La façon de gérer d’un gouvernement est logiquement influencée par la culture ambiante et par les racines historiques du pays. La communication gouvernementale avec les médias en cas de crise est aussi fonction de l’environnement culturel du pays. La Chine a tendance à suivre le modèle occidental qui est reconnu comme le modèle de réussite dominant dans le monde moderne. Il s’agit de résoudre le conflit entre une aspiration à la modernité et le maintien d’une spécificité culturelle. Dans un système de communication gouvernementale avec les médias en cas de crise, il faut bien sûr résoudre le problème d'efficacité, mais le plus important est de résoudre les problèmes d'adaptation culturelle. Chaque culture a ses propres forces et ses valeurs essentielles. La culture chinoise donne la priorité à la collectivité, alors que la culture occidentale privilégie l’individu. La mondialisation induite par la révolution médiatique amène chaque culture à rencontrer les autres, mettant en avant des différences et particularités qui sont autant d’occasions de mieux se connaître et se compléter. / The way of managing of a government is logically influenced by the ambient culture and the historical roots of the country. The governmental communication with the media in the event of crisis is also function of the cultural environment of the country. China tends to follow the Western model which is recognized like the model of success dominating in the modern world. It is a question of solving the conflict between an aspiration with modernity and the maintenance of a cultural identity. In a governmental communication system with the media in the event of crisis, it is initially necessary to solve the problem of effectiveness, but most important is to solve the problems of cultural adaptation. Each culture has its own forces and its essential values. The chinese culture gives the priority to the community, where as the Western culture privileges the individual. The universalization induced by the media revolution leads each culture to meet the others with specific knowledge which gives the opportunities to know each other better and be supplemented.
24

Ferramenta para modelagem de sistemas de comunicação. / Tool for modeling communication systems.

Zapata, Catalina 06 August 2007 (has links)
Este trabalho apresenta uma ferramenta para a simulação de sistemas de comunicação utilizando modelos em alto nível para cada um dos blocos empregados. A ferramenta é baseada em modelos comportamentais de blocos de Radio Freqüência (RF), o que reduz custos, tempo de simulação e permite um rápido diagnóstico de problemas precoces no projeto de um sistema de comunicação sem fio. O desenvolvimento de blocos, como o LNA (Low Noise Amplifier), o MIXER, o LO (Oscillator Local) e o PA (Power Amplifier), facilita a implementação de qualquer arquitetura de Transmissão e de Recepção. Para isso foram levados em consideração efeitos de ruído, não linearidade e ganho no modelo dos blocos. Com isto se espera que a ferramenta ajude no projeto de circuitos integrados de um sistema de blocos em cascata, onde o usuário possa selecionar, configurar e simular o sistema. Na utilização da ferramenta é indispensável um conhecimento prévio das características e especificações em nível de sistema. Assim, se poderão fazer mudanças nos parâmetros de blocos, que permitirá então analisar compromissos existentes entre ruído, ganho e distorção do sinal através de todo o caminho, antes mesmo de se ter uma resposta definitiva. A ferramenta de simulação é implementada em Simulink, que é um pacote (toolbox) de Matlab, amplamente utilizado no desenvolvimento de algoritmos e blocos de comunicação. A interação e ambiente gráfico da ferramenta facilitam o uso pelas pessoas envolvidas direta e indiretamente com o projeto de circuitos. Finalmente, para verificar a ferramenta desenvolvida foi feito um estudo de caso, onde se modelou e simulou o padrão Bluetooth. / This work presents a tool for the simulation of Communication Systems using macromodels for each block used. The tool is based on behavioral models of Radio Frequency (RF) blocks, which minimize cost, simulation time and allows a fast determination of problems in the early phases of the design of a Wireless Communication System. The development of blocks like the LNA (Low Noise Amplifier), the MIXER, the LO (Local Oscillator) and the PA (Power Amplifier), helps to implement any architecture for transmission and reception. For that, the effects of noise, non-linearity and gain in the behavioral model of the blocks were considered. With this, it is expected that the tool will help the design of integrated circuits of a system with cascade blocks, where the user can select, set up and simulate the system. In order to use the tool, previous knowledge of the characteristics and specifications of the system is necessary. In this way, it will be possible to change the parameters of blocks, allowing the analysis of tradeoffs between noise, gain and distortion of the signal through the system, before having a definite answer. The tool is implemented in Simulink, which is a toolbox of Matlab, normally used in the development of communication blocks and algorithms. The graphic environment of the tool allows a straightforward use for people involved directly or indirectly with the Circuit Design. Finally, in order to verify the developed tool, a case study was performed where the Bluetooth standard was modeled and simulated.
25

Ferramenta para modelagem de sistemas de comunicação. / Tool for modeling communication systems.

Catalina Zapata 06 August 2007 (has links)
Este trabalho apresenta uma ferramenta para a simulação de sistemas de comunicação utilizando modelos em alto nível para cada um dos blocos empregados. A ferramenta é baseada em modelos comportamentais de blocos de Radio Freqüência (RF), o que reduz custos, tempo de simulação e permite um rápido diagnóstico de problemas precoces no projeto de um sistema de comunicação sem fio. O desenvolvimento de blocos, como o LNA (Low Noise Amplifier), o MIXER, o LO (Oscillator Local) e o PA (Power Amplifier), facilita a implementação de qualquer arquitetura de Transmissão e de Recepção. Para isso foram levados em consideração efeitos de ruído, não linearidade e ganho no modelo dos blocos. Com isto se espera que a ferramenta ajude no projeto de circuitos integrados de um sistema de blocos em cascata, onde o usuário possa selecionar, configurar e simular o sistema. Na utilização da ferramenta é indispensável um conhecimento prévio das características e especificações em nível de sistema. Assim, se poderão fazer mudanças nos parâmetros de blocos, que permitirá então analisar compromissos existentes entre ruído, ganho e distorção do sinal através de todo o caminho, antes mesmo de se ter uma resposta definitiva. A ferramenta de simulação é implementada em Simulink, que é um pacote (toolbox) de Matlab, amplamente utilizado no desenvolvimento de algoritmos e blocos de comunicação. A interação e ambiente gráfico da ferramenta facilitam o uso pelas pessoas envolvidas direta e indiretamente com o projeto de circuitos. Finalmente, para verificar a ferramenta desenvolvida foi feito um estudo de caso, onde se modelou e simulou o padrão Bluetooth. / This work presents a tool for the simulation of Communication Systems using macromodels for each block used. The tool is based on behavioral models of Radio Frequency (RF) blocks, which minimize cost, simulation time and allows a fast determination of problems in the early phases of the design of a Wireless Communication System. The development of blocks like the LNA (Low Noise Amplifier), the MIXER, the LO (Local Oscillator) and the PA (Power Amplifier), helps to implement any architecture for transmission and reception. For that, the effects of noise, non-linearity and gain in the behavioral model of the blocks were considered. With this, it is expected that the tool will help the design of integrated circuits of a system with cascade blocks, where the user can select, set up and simulate the system. In order to use the tool, previous knowledge of the characteristics and specifications of the system is necessary. In this way, it will be possible to change the parameters of blocks, allowing the analysis of tradeoffs between noise, gain and distortion of the signal through the system, before having a definite answer. The tool is implemented in Simulink, which is a toolbox of Matlab, normally used in the development of communication blocks and algorithms. The graphic environment of the tool allows a straightforward use for people involved directly or indirectly with the Circuit Design. Finally, in order to verify the developed tool, a case study was performed where the Bluetooth standard was modeled and simulated.
26

Enhancement and performance analysis for 3D beamforming systems

Xu, Cheng January 2018 (has links)
This thesis is about the researching for 5th generation (5G) communication system, which focus on the improvement of 3D beamforming technology in the antenna array using in the Full Dimension Multiple-Input Multiple-Output (FD-MIMO) system and Millimeter-wave (mm-wave) system. When the 3D beamforming technology has been used in 5G communication system, the beam needs a weighting matrix to direct the beam to cover the UEs, but some compromises should be considered. If the narrow beams are used to transmit signals, then more energy is focused in the desired direction, but this has a restricted coverage area to a single or few User Equipments (UEs). If the BS covers multiple UEs, then multiple beams need to be steered towards more groups of UEs, but there is more interference between these beams from their side lobes when they are transmitted at same time. These challenges are waiting to be solved, which are about interference between each beam when the 3D beamforming technology is used. Therefore, there needs to be one method to decrease the generated interference between each beam through directing the side lobe beams and nulls to minimize interference in the 3D beamforming system. Simultaneously, energy needs to be directed towards the desired direction. If it has been decided that one beam should covera cluster of UEs, then there will be a range of received Signal to Interference plus Noise Ratio (SINR) depending on the location of the UEs relative to the direction of the main beam. If the beam is directed towards a group of UEs then there needs be a clustering method to cluster the UEs. In order to cover multiple UEs, an improved K-means clustering algorithm is used to cluster the multiple UEs into different groups, which is based on the cosine distance. Itcan decrease the number of beams when multiple UEs need be covered by multiple beams at same time. Moreover, a new method has been developed to calculate the weighting matrix for beamforming. It can adjust the values of weighting matrix according to the UEs' location and direct the main beam in a desired direction whilst minimizing its side lobes in other undesired directions. Then the minimum side lobe beamforming system only needs to know the UEs' location and can be used to estimate the Channel State Information (CSI) of UEs. Therefore, the scheme also shows lower complexity when compared to the beamforming methods with pre-coding. In order to test the improved K-means clustering algorithm and the new weighting method that can enhance the performance for 3D beamforming system, the two simulation systems are simulated to show the results such as 3D beamforming LTE system and mm-wave system.
27

Análise de sistemas de comunicação para computação paralela em clusters. / Communication system analysis for cluster parallel computing.

Rosa, Bruno Otto Theodoro 26 February 2002 (has links)
Apesar do aumento constante da largura de banda das tecnologias de rede de computadores as aplicações de processamento paralelo ainda necessitam de uma latência de comunicação mais baixa que a oferecida. Este aspecto não tem sido contemplado por estas tecnologias de rede pois está relacionado à maneira como o sistema operacional utiliza-se dos recursos do hardware com relação aos dados enviados pelas aplicações dos usuários. Neste trabalho apresentamos um estudo da técnica para diminuição desta latência e as características necessárias para implementação deste tipo de sistemas, incluindo mecanismos de transferência de dados, técnicas para tradução de endereços, proteção, transferência de controle, grau de confiabilidade e implementação de \"Multicasting\". Apresentamos também o estudo de um sistema já implementado, chamado M-VIA, comparando seu desempenho com o TCP/IP tradicional. / Despite the constant bandwidth increase in computer networks parallel processing tasks still require a lower communication latency than offered. This necessity has not been addressed by these network technologies because it is related to how operating systems use hardware resources to send user data through network. In this work we present strategies to lower latency and the requirements to implement these systems, including data transfer mechanisms, address translation , security, control transfer, reliability and \"Multicasting\" deployment . We also present a ready to use system, M-VIA, comparing it to traditional TCP/IP performance.
28

EVIDENCE-BASED PRACTICES FOR IMPROVING COMMUNICATION SKILLS OF STUDENTS WITH MODERATE-TO-SEVERE DISABILITIES

BARTLETT, AMBER 01 June 2018 (has links)
Communication deficits are often evident in students with moderate-to-severe developmental disabilities. For these students, basic communication needs, like asking to use the restroom, requesting food or expressing discomfort are a challenge. Frustration caused by communication deficits can lead the student to express interfering behaviors, which may interrupt student learning. This paper identifies and describes evidence-based practices (EBPs) used to increase functional communication skills for students with moderate-to-severe developmental disabilities. This review focuses on functional communication training (FCT) and the picture exchange communication system (PECS) and their use to increase functional communication skills. The study also explains how to implement FCT and PECS and the results and challenges that may take place during the implementation process. This is an informative paper intended for special education teachers who work with students with moderate-to-severe disabilities.
29

The role and function of human resource practice after M&A process

Kuo, Shu-Hsuan 05 September 2011 (has links)
Whether it is Forbes, The Globe & Mail, The Wall Street Journal or Harvard Business Review, one can¡¦t help but notice that most accounts of business mergers are about what went wrong! In fact, over 70% of all mergers and acquisitions fail to achieve original financial expectations. That is a traumatic statistic. Additionally, although the merging entities give a great deal of importance to financial matters and the outcomes, HR issues are the most ignored ones. To be ironical, many studies have shown that most of the mergers fail to bring out the desired outcomes due to ¡§people-related¡¨ issue. The uncertainty brought out by poorly managed HR issues in mergers and acquisitions have been the major reason for these failures. The human resource issues in the mergers and acquisitions (M&A) can be classified in two phases the pre-merger phase and the post merger phase. Some literature provides ample evidence of difference in between the human resource activities in the two stages: the pre-acquisition and post acquisition period. However, we will focus on post acquisition period. The post acquisition period involves an assessment of the cultural and organizational differences, which will include the organizational cultures, role of leaders in the organization, and the management styles. The usual impacts, such as high turnover rate, decrease in the morale, motivation, and even lead to M&A failures. The other issues in the M&A activity are the changes in the HR policies, downsizing, layoffs, stress on the workers, and information system issues. As a result, human resource system issues in M&A activity are occupying a crucial position, indeed, human resource planning, compensation designs, performance appraisal system, employee development and employee relations should be given in the priority. Beside, the M&A activity also causes changes in their well defined career paths and future opportunities in the organization. Some employees also have to be relocated or assigned new jobs. Accordingly, HR will place employees in a completely different situation with new job profiles and work teams or design the job rotation programs. This may pose a tremendous impact on the performance of the employees. Therefore, HR may also need to develop a variety of training system and communication system to rebuild self-esteem of each employee. Those programs will enhance employees to obtain ability and create their potentials. Finally, the compensation structure among the organizations may also have a unavoidable difference, for example, one of firms may have performance based pay while other may have higher component of fixed pay; Hence the differences in compensation structure and performance appraisal systems also need to be re-evaluated so as to bring equity in the human resource systems and to treat employees at the equal level. Simultaneously, the employee relations issues will gain more importance in the acquisitions of Taiwan¡¦s industries. The power equation between management and unions is bound to change with the acquisition. The acquiring management also needs to keep track of number of unions in the workplace and equations between HR department and unions. Hence, developing a harmony relationship should be put in the first place. To sum up, this will require study of management-union equation, employee contracts, political linkages of the unions, compensation related clauses, number of union and dynamics between the unions. To sun up, once company accomplish those conditions, it will elevate the successful rate of M&A.
30

Development of Micro-transformer by MEMS Technology for Microwave Communication System

Sun, Chian-Hao 28 July 2012 (has links)
The conventional planar micro transformers presented very low quality-factor (Q<10) and very high insertion loss (-6 ~ -10 dB) at high operation frequency since most of the microwave power is dissipated through the silicon substrate. To increase the quality-factor and reduce the insertion loss of silicon-based transformers, this dissertation presents a two-port and three-port micro transformers with suspending structure utilizing the micro-electro-mechanical systems (MEMS) technology. The proposed silicon-based transformers are constructed by two winding and suspending micro inductors. Each suspending micro inductor consists of a 0.32 &#x00B5;m-thick TaN/Ta/Cu bottom electrode, a 10 &#x00B5;m-height supporting copper vias and a 6 &#x00B5;m-thick spiral copper conducting layer. This research adopts the Taguchi method and commercial electromagnetic simulation software (Ansoft-HFSS) to optimize the dimensional specifications of the copper conducting layer. Many high frequency characteristics of the suspending micro transformers are simulated, including the inductance, the magnetic coupling factor, the quality-factor, the magnitude imbalance, the phase imbalance, the common mode rejection ratio (CMRR) and the insertion loss. In this research, the surface micromachining and electrochemical deposition techniques are used to implement the suspending micro transformers. The main fabrication steps include five photolithography and eight thin-film deposition processes. According to the simulation and measurement results from the commercial network analyzer (Agilent-E8364B) and software (Agilent-ADS), the implemented two-port transformer demonstrates a high magnetic coupling factor (0.78) and a very high quality-factor (Q=17.20) at 5.2 GHz. On the other hand, the proposed three-port transformer presents a low magnitude imbalance (-0.02 dB), a low phase imbalance (1.65¢X), a high CMRR (36.78 dB) and a very low insertion loss (-4.52 dB) under the same operation frequency. In this dissertation, a novel suspending micro transformer has been developed and characterized. The proposed micro transformer is very suitable for being used in the portable microwave communication system due to its small chip size (0.7 mm¡Ñ0.7 mm¡Ñ0.5 mm) and excellent high-frequency characterization.

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