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‣ Metodologia para a coordenação e seletividade da proteção direcional de sobrecorrente em sistemas de transmissão de energia elétrica; Methodology for the coordination and selectivity of directional overcurrent protection in electrical power transmission systems

Negrão, Danilo Luiz Alves
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 31/03/2015 Português
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Este trabalho propõe uma nova metodologia para a solução do problema de coordenação de relés direcionais de sobrecorrente em sistemas de transmissão em malha. São utilizadas informações sobre a atuação do relé como dispositivo de proteção principal (ou retaguarda local no caso de se considerar o relé de distância) e também de sua atuação como proteção de retaguarda remota, fornecendo uma base mais sólida para definição dos ajustes. A partir de uma série de critérios determinados de acordo com a instalação, define-se uma área de ajuste do relé, diretamente sobre sua curva de atuação. Sobre esta área, aplica-se um método de otimização capaz de encontrar o melhor ajuste possível para o dispositivo em análise. A metodologia é aplicada sem a necessidade de uma análise topológica do sistema, sendo que as informações da localização do relé e sua integração com os outros dispositivos de proteção são resumidas durante o estudo de curto-circuito, que fornece os dados de entrada para a metodologia. O algoritmo resume os critérios de coordenação em pontos de referência, de modo que a análise é feita relé a relé, eliminando assim problemas comuns como o de tratamento de banco de dados e ganhando em agilidade e simplicidade no tratamento do problema. A resposta fornecida é bastante intuitiva...

‣ Modelagem da propagação não linear em fibras ópticas : sistemas de transmissão de dados e amplificadores paramétricos; Modeling non linear propagation in optical fibers : data transmission systems and optical parametric amplifiers

Andres Anibal Rieznik
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/03/2008 Português
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Apresentamos métodos para a otimização das simulações da propagação não linear da luz em fibras ópticas a través do Método de Split-Step Fourier (SSFM). Os dois efeitos considerados na modelagem da propagação são a dispersão e o efeito Kerr instantâneo. Estudamos tanto as equações acopladas considerando os dois modos principais de polarização quanto as equações escalares, estas últimas aplicáveis em situações em que o campo pode ser considerado um escalar, como em fibras isotrópicas com todos os campos linearmente polarizados e paralelos. Mostramos que o método que propomos para resolver as equações escalares é ordens de grandeza mais rápido do que outros métodos apresentados recentemente na literatura científica na modelagem de sistemas de transmissão de dados. No caso das equações acopladas, mostramos que o método proposto fornece resultados acurados na modelagem de amplificadores paramétricos e o utilizamos para validar um modelo analítico de seis ondas que nós mesmos desenvolvemos. Também utilizamos o método proposto para as equações acopladas para estudar o impacto das variações aleatórias da birrefringência sobre o ganho de amplificadores paramétricos, mostrando a importância da modelagem realista destas flutuações. Todos os códigos desenvolvidos são disponibilizados e distribuídos sob uma licença do tipo de software livre através de um portal criado na internet especialmente para esse fim.; We introduce optimized models and algorithms for the simulation of non linear propagation in optical fibers using the split-step Fourier Method (SSFM). Dispersion and the Kerr effect are the two main effects considered in the simulations. We study the coupled equations...

‣ An optimal control approach to dynamic routing in data communication networks : part I--principles

Fonte: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Publicador: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology
Formato: 72 p.; application/pdf
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Franklin H. Moss and Adrian Segall.; Bibliography: p. 72.; "September 1978."; Supported by the Advanced Research Project Agency (monitored by ONR) under Contract no. N00014-75-C-1183 Technion Research and Development Foundation Ltd. no. 050-383

‣ An optimal control approach to dynamic routing in data communication networks : part II--geometrical interpretation

Fonte: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Publicador: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology
Formato: 42 p.; application/pdf
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Franklin H. Moss and Adrian Segall.; Bibliography: p. 42.; "September 1978."; Supported by the Advanced Research Project Agency (monitored by ONR) under Contract no. N00014-75-C-1183 Technion Research and Development Foundation Ltd. no. 050-383

‣ Optimal distributed routing for virtual line-switched data networks

Fonte: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Publicador: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology
Formato: 35 p.; application/pdf
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Adrian Segall.; Bibliography: p. 35.; "September 1978."; Supported by the Advanced Research Project Agency (monitored by ONR) under Contract no. N00014-75-C-1183

‣ A busy-tone-multiple-access-type scheme for packet-radio networks

Fonte: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Publicador: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology
Formato: 20 p.; application/pdf
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Moshe Sidi and Adrian Segall.; Bibliography: p. 17.; "June, 1981."; Office of Naval Research contract No. ONR/N00014-77-C-0532

‣ Introduction to data communication

Fonte: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Publicador: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology
Formato: 10 leaves; 820656 bytes; application/pdf
Português
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Pierre A. Humblet.; "January, 1983." Caption title.; Bibliography: leaves 9-10.; NSF Grant ECS 79-19880

‣ Supporting GHG Mitigation Actions with Effective Data Management Systems

Partnership for Market Readiness
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Trabalho em Andamento
Português
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The Partnership for Market Readiness (PMR) is a global partnership, which provides funding and technical assistance to support the design and development of market-based instruments to reduce greenhouse gas (GHG) emissions. The PMR is country-led and builds on countries own mitigation priorities. It emphasizes improving technical and institutional capacity to scale up mitigation efforts, including domestic emissions trading, crediting mechanisms and carbon taxes, among others. The report contains three parts. First, it provides an overview of the types of data management systems included in this analysis, namely, systems that support: (1) national level inventories, (2) facility-level reporting, and (3) carbon asset registries as well as other systems for clean energy and energy efficiency policies. The first part also provides a snapshot of four cases studies (the United Kingdom, Australia, the United States, Germany; Annexes to this report includes full descriptions of the case studies). Secondly, the report presents lessons learned from the case studies...

‣ A performance analysis of management information due to data traffic provisioning in a SONET/SDH communications network

Tay, Yeong Kiang Winston.
Fonte: Monterey California. Naval Postgraduate School Publicador: Monterey California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xx, 57 p. : col. ill. ;
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An evaluation of the performance of a SONET management system was conducted to better understand its management capabilities due to network disruptions in the presence of a traffic load. This study analyzed the Cisco Transport Manager (CTM) which manages a testbed of four Cisco ONS15454 optical systems. The network was injected with HTTP and FTP traffic generated by the Spirent Smartbits system installed with TeraMetrics Gigabit Ethernet modules and load calibration configured by the Spirent Avalanche software. To simulate real-world situations, power disruptions were applied to the network while collecting CTM traffic using Ethereal. Using queuing analysis, the arrival rates and service times were computed for various CTM traffic components and a utilization for 2500 network elements (NE) extrapolated. Self-similarity analysis was performed and the logvariance was plotted to extract the Hurst values. Finally, the results and findings were compared with prior research for loading and no-loading cases. The results of this study are useful in determining the maximum number of network elements manageable in a disruptive environment. Final analysis on the effects of link utilization on the queue size showed that the CTM is able to manage more NEs when the network is disrupted. Unfortunately...

‣ Device profiling analysis in Device-Aware Network

Tsai, Shang-Yuan
Fonte: Monterey California. Naval Postgraduate School Publicador: Monterey California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xiv, 67 p. : ill. (some col.)
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Approved for public release, distribution is unlimited; As more and more devices with a variety of capabilities are Internet-capable, device independence becomes a big issue when we would like the information that we request to be correctly displayed. This thesis introduces and compares how existing standards create a profile that describes the device capabilities to achieve the goal of device independence. After acknowledging the importance of device independence, this paper utilizes the idea to introduce a Device-Aware Network (DAN). DAN provides the infrastructure support for device-content compatibility matching for data transmission. We identify the major components of the DAN architecture and issues associated with providing this new network service. A Device-Aware Network will improve the network's efficiency by preventing unusable data from consuming host and network resources. The device profile is the key issue to achieve this goal.; Captain, Taiwan Army

‣ Defense Data Network (DDN) Performance Analysis Using Probability Modeling

Gaver, Donald Paul; Jacobs, Patricia A.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Relatório
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The Data Defense Network (DDN) is a large packet switching network that services elements of the U.S. Department of Defense (DOD). The emphasis of this report is to perform probabilistic analysis of certain features of the DDN system with a view of enhancing or 'optimizing' measures of service such as data base throughput and the waiting times experienced by data-base-transfer customers. The particular questions addressed, and the models constructed, are in response to tasking statements supplied by personnel from the Defense Communications Engineering Center, Reston, Virginia. In Section 2 models are presented to study the optimal length of a packet subject to transmission errors. When a data transfer is to occur the total collection of bits that comprise the data base is divided into packets, i.e., subcollections of contiguous bits from the data base plus a header carrying address information. In Section 3 models are introduced to study the effect on D's buffer of all sources retransmitting at a retransmission interval of length 8. We also model the behavior of one form of congestion control, exponential backoff, a procedure that increases successive time-out intervals possibly from 8 to 28, 28 to 48, etc. In summary, probabilistic models have been constructed to study the effect of packet size and message size on system throughput and response time of a data-transfer operation. The effect of packet retransmission on response times has also been evaluated. (KR); Defense Communications Agency...

‣ Concept of Feedback in Future Computing Models to Cloud Systems

Pluzhnik, Evgeniy; Nikulchev, Evgeniy; Payain, Simon
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 19/02/2014 Português
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Currently, it is urgent to ensure QoS in distributed computing systems. This became especially important to the development and spread of cloud services. Big data structures become heavily distributed. Necessary to consider the communication channels and data transmission systems and virtualization and scalability in future design of computational models in problems of designing cloud systems, evaluating the effectiveness of the algorithms, the assessment of economic performance data centers. Requires not only the monitoring of data flows and computing resources, but also the operational management of these resources to QoS provide. Such a tool may be just the introduction of feedback in computational models. The article presents the main dynamic model with feedback as a basis for a new model of distributed computing processes. The research results are presented here. Formulated in this work can be used for other complex tasks - estimation of structural complexity of distributed databases, evaluation of dynamic characteristics of systems operating in the hybrid cloud, etc.; Comment: 10 pages. arXiv admin note: substantial text overlap with arXiv:1402.1469

‣ Performance of quantum data transmission systems in the presence of thermal noise

Cariolaro, G.; Pierobon, G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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In the literature the performance of quantum data transmission systems is usually evaluated in the absence of thermal noise. A more realistic approach taking into account the thermal noise is intrinsically more difficult because it requires dealing with Glauber coherent states in an infinite--dimensional space. In particular, the exact evaluation of the optimal measurement operators is a very difficult task, and numerical approximation is unavoidable. The paper faces the problem by approximating the P-representation of the noisy quantum states with a large but finite number of terms and applying to them the square root measurement (SRM) approach. Comparisons with the exact solution obtained with convex semidefinite programming show that the SRM approach gives quite accurate results. As application, the performance of quadrature amplitude modulation (QAM) and phase shift keying (PSK) systems is considered. In spite of the fact that the SRM approach is not optimal and overestimates the error probability, also in these cases the quantum detection maintains its superiority with respect to the classical homodyne detection.; Comment: 19 pages, 5 figures, accepted for publication in IEEE Trans. on Communications

‣ Real-time data acquisition, transmission and archival framework

Agarwal, Piyush
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
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Most human actions are a direct response to stimuli from their five senses. In the past few decades there has been a growing interest in capturing and storing the information that is obtained from the senses using analog and digital sensors. By storing this data it is possible to further analyze and better understand human perception. While many devices have been created for capturing and storing data, existing software and hardware architectures are aimed towards specialized devices and require expensive high-performance systems. This thesis aims to create a framework that supports capture and monitoring of a variety of sensors and can be scaled to run on low and high-performance systems such as netbooks, laptops and desktop systems. The proposed architecture was tested using aural and visual sensors due to their availability and higher bandwidth requirements compared to other sensors. Four different portable computing devices were used for testing with a varied set of hardware capabilities. On each of the systems the same suite of tests were run to benchmark and analyze CPU, memory, network, and storage usage statistics. From the results it was shown that on all of these platforms capturing data from multiple video, audio and other sensor sources was possible in real-time. Performance was shown to scale based on several factors...

‣ Virtualization and shared Infrastructure data storage for IT in Kosovo institutions

Zogaj, Gani
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Capstone Project
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This capstone project addressed the need to strengthen the centralization and security of the electronic data from various national institutions in Kosovo. Most of the electronic data in Kosovo Institutions are separated in so many server rooms in different institutions and different locations. The Republic of Kosovo institutions have different systems of data stored in different physical spaces. Most of these data should be exchangeable in different systems and different data bases. The country lacks physical security in the current system of data security and professional staff for maintaining such data (databases, applications, and other electronic data). The budget of Kosovo is making higher and unnecessary expenditure in the field of information and technology. This project would be a good alternative in order to reduce budgetary expenditure of Kosovo ... The outcome of this project provides recommendations in order to achieve the goals of the project. The three main recommendations of the project are centralization, virtualization and business continuity.; Figures and tables -- List of acronyms -- Executive summary -- Chapter 1. Virtual systems globally -- Chapter 2. Information and communication technology in Kosovo institutions -- Chapter 3. Integration of ICT systems -- Chapter 4. Virtualization -- Chapter 5. Optimizing of resources -- Chapter 6. Financial savings -- Chapter 7. Final discussion and recommndations -- Appendix 1 -- Appendix 2.; Includes bibliographical references.

‣ The Future of data communications system design

Kellow, Kenneth
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
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The Information Technology universe and its data communications subset was created largely due to advances in integrated circuit technology. Primarily focused on layer 2 of the OSI model, silicon integration is a technology upon which much of data communications is constructed. Over the past forty years advances in integrated circuit technology have manifested themselves through shrinking structural dimensions and increases in performance. This combination of shrinking structural dimensions also known as circuit density, and performance increases, also known as circuit speed, have led to long term compound productivity increases and a seemingly never ending menu of data communications applications. Recent beneficiaries include 10/100 Ethernet systems, gigabit Ethernet systems, asynchronous transfer mode systems (ATM), synchronous optical network systems (SONET), and wireless systems. Some have argued that these density and speed improvements have doubled every eighteen months to two years over the past thirty to forty years and are directly responsible for the information age revolution in which we exist today. Others have projected that past integrated circuit productivity increases cannot continue indefinitely and that we may be approaching and end to integrated circuit compound productivity increases that fuel the information age. But does the purported end to compound silicon productivity increases mean an end to the growth of data communications systems or the larger role of information technology? Or are there other factors which may fill the role at the system level by using silicon in a more productive way? The statement of this thesis is that the end of compound silicon productivity will not be an important impact to data communications over the next five years.

‣ Asymmetrical digital subscriber line (ADSL) an in-depth study

Kernan, John
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
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Asymmetrical Digital Subscriber Line (ADSL) is one member of a group of broadband access technologies that uses the existing copper-based local loop of the analog PSTN for high-speed digital data transmission. One feature of ADSL is that it permits analog voice POTS transmissions to continue uninterrupted over the same wiring. Specifically, POTS continues to use the 0 to 4 KHz frequency range of the copper wiring, while ADSL uses bandwidth starting at 25 KHz and extending up to approximately 1.1 MHz for data transmission. The term "asymmetrical" refers to the fact that data rates downstream (to the user) and upstream (from the user) are not the same. Typical ADSL data rates range from 1.536 to 6.144 Mbps downstream and from 16 to 640 Kbps upstream. Local loop length, wire size, and the presence of devices to improve voice communication such as bridged taps and loading coils all affect ADSL data rates. Digital data is coded by one of two methods: Discrete Multitone Modulation (DMT) or Carrierless Amplitude and Phase Modulation (CAP). Echo control is also accomplished by one of two methods: Frequency Division Multiplexing (FDM) or echo cancellation. This paper consists of four sections: 1) A technical review and comparison of the CAP and DMT line encoding technologies. 2) A market review of the presence of CAP and DMT technologies in customer premise equipment (CPE) such as modems and routers. 3) A review of the POTS physical layer that exists between the ADSL subscriber and the Telco CO...

‣ A cost and performance analysis of the three electronic communication systems currently in use in the printing and publishing industry

Richards, Susan
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
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This study describes and evaluates the three electronic graphic communication systems presently used by the printing and publishing industry. The author has selected generic system names for each of the systems. These are: System 1: Page Facsimile System 2: Character-Encoding System 3: Pixel Density-Map Page Facsimile systems are primarily used by newspaper publishers. The Character-Encoding and Pixel Density-Map systems are alternate methods primarily used by newsweekly magazine publishers. All three communication systems offer the user a means of transmitting editorial, and in some cases advertising pages, to remote printing facilities for manufacturing and distribution. Each electronic graphic communication system is investigated in depth. The study provides specific information for the potential user, and the current user. The problem for the user is how to best match the communication system, i.e. how the system operates, the cost and performance of that system, with the user's requirement for transmitting graphic information. Based on the full evaluation of each of the systems in the study, the author concludes the following: System 1: Page Facsimile The Page Facsimile system is relatively simple for the user to install and operate. However...

‣ A Field study to determine the feasibility of establishing remote data transmission of advertising for a local newspaper

McKeever, John Jr
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
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In recent years, local newspaper's advertising revenues have been seriously eroded by the presence of competing electronic media. Technological innovation in cable television (CATV), interactive multimedia, broadcast television and Compact Disc-Read-Only Memory (CD-ROM) have proven to be a double-edge sword for local newspaper advertising revenues. On one hand, these technologies provide lower cost, high quality advertisement which target larger, more diverse audiences. On the other hand, the same technological innovations (high speed digital transmission, high quality input and output devices, and the widespread use of portable computing) have created a means for local newspapers to protect their advertising base and realize increased customer satisfaction through on-site interaction in early phases of ad development through remote data transmission. In this context remote data transmission involves the use of high speed transmission facilities capable of transmitting data of rates in excess of 56,000 bits per second. Adobe Acrobat 2.0 was used as a means of maintaining the integrity of the advertisement's elements as part of the transmission process. The author conducted a field experiment to determine the feasibility of remote data transmission of advertising between Advertising Services at Syracuse Newspapers in Syracuse...

‣ Efficient transmission and classification of hyperspectral image data

Jia, Xiuping; Richards, John
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Artigo de Revista Científica
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An extension of a newly developed cluster-space representation is applied to efficient data transmission and classification. Cluster-space classification, which is an automatic hybrid supervised and unsupervised classification procedure, can be performed