Orientador: Hugo Enrique Hernandez Figueroa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-05T07:05:01Z (GMT). No. of bitstreams: 1 Albuquerque_EdisondeQueiroz_D.pdf: 2450262 bytes, checksum: 1142d9b235574921d845ac5246fbe250 (MD5) Previous issue date: 2005 / Resumo: Este trabalho está baseado em uma experiência real, vivida no dia-a-dia do nosso trabalho na Empresa Brasileira de Telecomunicações S.A, EMBRATEL, quando da busca de ferramentas capazes de viabilizar o permanente treinamento dos Consultores Técnicos da empresa, localizados em diferentes partes do nosso país, em face da escassez de recursos financeiros e de tempo. Para tanto, iniciamos com uma retrospectiva histórica da Educação a Distância no mundo, seu presente e suas tendências visíveis. Depois, apresentamos uma descrição dos protocolos multicasting existentes, seguido de nossa proposta. Apresentamos, também, uma simulação usando o Simulador ns-2 de maneira a comprovar o correto funcionamento do protocolo proposto e avaliar seu desempenho. O núcleo desta tese é a proposta de um novo protocolo multicasting, elemento essencial para a otimização da rede de suporte, um imperativo para a eficiência de seu funcionamento e, principalmente, da diminuição de seu custo, tendo em vista a situação ideal de se transmitir voz e vídeo para garantir que uma aula a distância será o mais próximo possível de uma aula presencial, conforme aponta o resultado de pesquisas referenciadas no presente texto, uma vez que vídeo é uma aplicação que demanda grande largura de banda / Abstract: This work is based on a real life situation, experienced in our daily work at Empresa Brasileira de Telecomunicações S.A, EMBRATEL, when pursuing tools that would allow the continuous training of its staff of Technical Consultants. The Technical Consultants were spread all over Brasil, a country of continental dimensions. Time and cost were obstac1es to achieve the above mentioned training. This thesis starts providing a short account of the historical milestones on Distance Learning. We added considerations on the state-of-the-art and scenarios of future developments, which were drawn taking into account social and economical policies. Routing and existing multicasting protocols are described and compared with the bidirectional multicast protocol proposed in this thesis. The main purpose of this thesis is the proposal of a new Multicasting Protocol, to support a new concept on which a teacher can be a student on a different subject by taking into account that we aim a Distance Learning environment inside a corporation. The ns-2 Simulator is used to simulate the perfect operation of the proposed protocol and evaluate its performance. The use of video is mandatory in order to achieve a maximum efficiency at c1ass. The rapid switching of video transmission from the teacher to a remote student that asks a question (so that all other students spread around the country can also see who is asking) and back to the teacher is mandatory and is what motivated the development of this new Multicast Protocol / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

Orientador: Nelson Luis Saldanha da Fonseca / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-13T20:11:45Z (GMT). No. of bitstreams: 1 Michel_NeilaFernanda_M.pdf: 1961141 bytes, checksum: f4470a332c9b5f764b7bd3b912c27db1 (MD5) Previous issue date: 2008 / Resumo: O protoloco TCP Reno começou a operar em 01 de Janeiro de 1983. Desde sua concepção, houveram expressivos avanços nas tecnologias de transmissão de dados, como a introdução de enlaces ópticos e de satélites, 'que permitem altas taxas de transmissão. O TCP Reno continua sendo o protocolo padrão na Internet. Entretanto existem inúmeras dificuldades na sua operação, que causam baixo desempenho em redes com produto banda-atraso elevado, devido ao mecanismo de atualização do tamanho da janela de congestionamento. Para superar suas deficiências, vários protocolos variantes do TCP Reno têm sido propostos com o objetivo de melhorar a utilização de recursos em redes de alta velocidade, e por esta razão são denominados "Protocolos para Redes de Alta Velocidade" . Para que as proposições de variantes do TCP levem a protocolos que operem eficientemente em redes com alto valor do produto banda-atraso, é necessário que se avalie quais variações da dinâmica do crescimento da janela de transmissão são efetivas. Nesta dissertação avalia-se um conjunto de protocolos variantes do TCP para redes de alta velocidade através de simulações. Diversas propriedades importantes para protocolos do tipo TCP são investigadas / Abstract: The importance of the Reno TCP protocol started operating in January 01 st, 1983. Since this milestone, there were expressive advances on data transmission technologies, such as those of optical fibers and satellite channels which allow high transmission rates on long distances. Reno TCP remains the Internet standard protocol. However, its operation presents several dificulties in networks with high bandwidth-delay product, producing poor performance due its window congestion mechanism. In order to overcome its deficiencies, several variants have been proposed with the aim of enhancing its utilization in high speed networks. These variants are generally called "High Speed Networks Protocols". Transmission chàracteristics, properties and performance evaluation are essencial to the identification of problems and avoidance of poor performance. In this dissertation a set of TCP variants protocols for high speed networks is evaluated. Several important properties of these protocols are investigated / Mestrado / Redes de Computadores / Mestre em Ciência da Computação

Este trabalho propõe a integração de técnicas de sensoriamento dinâmico, redes de dados sem fio e internet. A implementação dos nós da rede visa permitir o monitoramento de objetos que se movem tanto numa rede interna, limitada a uma edificação, quanto numa rede externa, através de coordenadas GPSs (Global Position Systems). A rede sem fio, que utiliza o protocolo ZigBee, é composta por sensores, atuadores e lâmpadas e é dotada de mobilidade através de controles remotos1. A rede ZigBee é integrada, através de um gateway, a uma rede TCP/IP para permitir o monitoramento e a atuação remota sobre ela, via um servidor HTTP e/ou uma rede de dados celular (GPRS), que, quando fora do alcance dos nós da rede ZigBee interna, torna-se responsável pelo envio de coordenadas GPS na rede externa, garantindo a onipresença do monitoramento. Além das adaptações na pilha TCP/IP e o desenvolvimento de um software que utiliza a rede GPRS para envio de coordenadas GPS, destacam-se, como contribuições originais desta tese: (i) a solução de problemas da pilha ZigBee original no tocante a endereçamento, que impossibilitava a mobilidade na rede - desta forma, uma nova técnica de endereçamento seqüencial foi implementada com sucesso; (ii) novo código que simulou o AES (Advanced Encryption Standard), tanto para encriptação quanto para desencriptação dos dados. Testes para validação dos protótipos desenvolvidos são apresentados / This MSc Thesis proposes the integration of dynamic sensing techniques, wireless data network and Internet. The implementation of network nodes aims to allow monitoring of moving objects, either inside an internal network, limited to one area, or in an external network, through GPS\'s (Global Position Systems). The wireless network, which uses the ZigBee protocol, is composed of sensors, actuators and lamps, and is endowed with mobility through remote controls. Thus, it is integrated, through a gateway, to a TCP / IP network to allow remote monitoring and acting on it via an HTTP server and / or a mobile data network (GPRS), responsible for sending the GPS coordinates on the external network, ensuring the ubiquity of monitoring. Further to adaptations in the TCP/IP stack and the development of a software that uses GPRS protocol to send GPS coordinates, the main contributions of this work are: (i) proposal of a new addressing technique, based on a sequential numbering of nodes, instead of the standard one, thus solving problems related to mobility in the network; (ii) proposal of a new security code to emulate AES (Advanced Encryption Standard), either for data encryption or decryption. Tests for validation of the developed prototypes will be presented

Made available in DSpace on 2016-08-17T14:52:53Z (GMT). No. of bitstreams: 1 Ricardo Henrique Bezerra Azoubel.pdf: 588389 bytes, checksum: 40c0c99f808c27d0a6967b9d18c9c22a (MD5) Previous issue date: 2004-09-24 / This work presents a platform of tests (testbed) inexpensive, constructed in a controlled environment composed by microcomputers and free softwares. It is implemented, in such platform, the differentiated service model (DiffServ), with expedited forwarding (PHB EF). It is basically considered, from the collection of metrics main of QoS (delay, jitter, loss and throughtput), the performance analysis of voice characteristic traffics, when submitted to experimental tests in some scenes and conditions. Initially, in an environment capable to differentiate traffics, flows generated by standardized voice coder/decoder (G.711 and G.726) are modeled, in which the packets size and the amount of aggregate flows are varied, in scenes with and without QoS. It is compared, after that, the behavior of flows generated by activity-silence (ON-OFF) and continuous (CBR) sources. Can be perceived in this study how much the packets size variation influence in the performance of the most priority packets. It is carried, in the sequence, a specific analysis of the aggregation factor in flows generated by ON-OFF sources, in which can be observed the action of the basic principle of the model DiffServ, where aggregate flows receive differentiated treatment. It is studied, finally, through the use of transport protocols (UDP and TCP) and of elastic flows of FTP type, how much the best effort traffic confuses the performance of voice modeled flows. / Este trabalho apresenta uma plataforma de testes (testbed) sem custos, construída num ambiente controlado composto por microcomputadores e softwares livres. Implementa-se, em tal plataforma, o modelo de serviço diferenciado (DiffServ), com encaminhamento expresso (PHB EF). Propõe-se, fundamentalmente, a partir da obtenção das principais métricas de QoS (atraso, jitter, perda e vazão), a análise do desempenho de tráfego característico de voz, quando submetido a testes experimentais em vários cenários e condições. Inicialmente, num ambiente capaz de diferenciar tráfego, modelam-se fluxos gerados por codificadores/decodificadores de voz padronizados (G.711 e G.726), em que se varia o tamanho dos pacotes e a quantidade de fluxos agregados, em cenários com e sem QoS. Compara-se, em seguida, o comportamento de fluxos gerados por fontes atividadesilêncio (ON-OFF) e contínuas (CBR). Pode-se perceber nesse estudo o quanto a variação do tamanho dos pacotes impacta no desempenho dos pacotes mais prioritários. Realiza-se, na seqüência, uma análise específica do fator agregação em fluxos gerados por fontes ONOFF e observa-se a atuação do princípio básico do modelo DiffServ, onde fluxos agregados recebem tratamento diferenciado. Estuda-se, por fim, através da utilização de protocolos de transporte (UDP e TCP) e de fluxos elásticos do tipo FTP, o quanto o tráfego de melhor esforço impacta no desempenho de fluxos modelados de voz.

Made available in DSpace on 2016-08-17T14:52:57Z (GMT). No. of bitstreams: 1 Jose Coelho de Melo.pdf: 1424511 bytes, checksum: 76fbc2d3ff58f82123072e2b8323be1a (MD5) Previous issue date: 2005-03-14 / This work presents several ways of using mechanisms of Quality of Service (QoS) in networks hardwired for links of short band. It is demonstrated that the use of mechanisms of QoS brings profits of performance for priority applications and rationality in the use of band resources. The work is developed in a test platform of Previdência Social. Implementations of the PHBs EF, Afs and BE are tested. The work has evaluated the capacities to offer guaranteed band, traffic priority, conditioning of traffic and the impact of the competition between traffic classes. The experiments are mounted using the architecture of differentiated services (DiffServ) of platform Cisco, that is the standard in the network of the Previdência Social and are manipulated the mechanisms of classification, control of congestion, policing and conformation of traffic. The results give subsidy for implementation of some models of QoS in IP networks, mainly for those that serve short band. / Este trabalho apresenta diversas maneiras de utilização dos mecanismos de Qualidade de Serviço (QoS) em redes ligadas por enlaces de banda estreita. É demonstrado que o uso de mecanismos de QoS traz ganhos de performance aos aplicativos prioritários e racionalidade no uso de recursos de banda. O trabalho é desenvolvido em uma plataforma de teste que retrata um seguimento da rede da Previdência Social. São testadas possíveis implementações dos PHBs EF, Afs e BE. São avaliadas as capacidades de oferecer largura de banda garantida, priorização de tráfego, condicionamento de tráfego e o impacto da concorrência entre classes de tráfego. Os experimentos são montados utilizando a arquitetura de serviços diferenciados (DiffServ) da plataforma Cisco, que é o padrão na rede da Previdência Social, e são manipulados os mecanismos de classificação, controle de congestionamento, policiamento e conformação de tráfego. O resultado apresentado dá subsídio para implementação de vários modelos de QoS em redes IP, principalmente para redes servidas por banda estreita.

Orientador: Leonardo de Souza Mendes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-21T21:10:42Z (GMT). No. of bitstreams: 1 Nunes_FabioPessoa_M.pdf: 6956532 bytes, checksum: 55194ac0a721f75279923f8424903edc (MD5) Previous issue date: 2012 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

[pt] Este trabalho examina o impacto da quantização vetorial das LSFs sobre a qualidade de voz em codecs a baixas taxas operando em redes IP e em diversos ambientes ruidosos. São considerados diferentes esquemas de quantização vetorial (QV) multiestágio com busca em árvore envolvendo QV sem memória e QV preditiva chaveada com 2 e 4 classes. A distribuição de perda de quadros em redes IP foi modelada de acordo com o Modelo de Gilbert e a avaliação de desempenho foi realizada tanto em termos das distorções espectrais como da qualidade de voz resultante de codecs a baixas taxas. Ainda neste trabalho, foi avaliada a qualidade da voz codificada após a utilização de uma técnica de supressão de ruído baseada em transformadas wavelets (Wavelet Denoising). / [en] This work investigates the impact of LSF vector quantisation over the voice quality in low rate codecs operating in IP networks. Tree-structured multistage vector quantisation (VQ) schemes involving memoryless VQ and switched-predictive VQ with 2 and 4 classes are considered. The packet loss frame distribution in IP networks was modelled according to the Gilbert Model and the performance was carried out both in terms of spectral distortions and the speech quality at the out put of low rate codecs. In this work, we also evaluated the quality of the coded speech after employing Wavelet Denoising.

The studied application area is a private bank with different branches located in different provinces around the country. There was not integrated security solution to provide communication among different branches. Some of these branches could communicate through the satellite and the others could communicate through a different technology, such as asynchronous transfer mode (ATM). Different bank security policies were applied and maintained for different branches separately. In addition, the number of branches is expected to grow during coming year in each province. The old topology was partial mesh and it could not support enough redundancy in case of disruption. If a connection between two branches failed, other branches might lose their connectivity as well. In addition, it could not achieve optimum routing. Providing integrated quality of service (QoS) for the wide area network (WAN) by using different technologies is not easy to achieve, and it causes so many problems for the system. The bank uses a variety of protocols for different applications, depending on its demand, so the new applied technology should not depend on protocols, or at least should support different protocols at a same time. In the old technology, the bank was responsible for granting availability and connectivity maintenance. Providing proper bandwidth is an important aspect in the bank scenario and for the old technology; supplying enough bandwidth was costly. As mentioned above, the old applied technology was dependent upon different protocols. Therefore, packets in different open system interconnection layers (OSI layers) would have to check thoroughly to find the source/ destination address, data and so on, to reach the correct destination. This might cause security problems for entire system. In addition, processing packet in each layer of the OSI model is time consuming. One important aspect for the retail-banking scenario is considering all features of the security domain, such as security policy, information security, physical security, access level control, integrated security for the system and so on. Some features of the security domain in this project were not covering completely, such as integrated information security, merged security policy, and integrated physical security for the system. In this project, all mentioned problems are solved by implementing a specific communication technology which can overcome the problems above. This technology supports multiple protocols, and it provides fast and secure communication. It can also cover redundancy and it does not cost as much as previous technologies like ATM and satellite. Easy provisioning is one feature of this technology. In this technology, the service provider is responsible for granting availability and connectivity maintenance. The mentioned features of the security domain, which were not covered by the old technology, will be covered by a proper, integrated security solution. The IP-based physical security systems provide centralized monitoring and they can define a merged security policy for all different branches around the country. Specific, pre-defined scenarios are created for different events in different situations.

[pt] Este trabalho faz um estudo da arquitetura Diffserv para oferecimento de QoS na internet.São revistos conceitos básicos e descritos os principais mecanismos de controle de tráfego.Utilizando o software NS2, avalia-se o desempenho desses algoritmos de controles de tráfego.Para um cenário específico foram estudados: disciplinas de serviço, mecanismos de gerenciamento de buffers, para diferentes fontes de tráfego, procurando-se obter medidas de desempenho que possam ser úteis em projetos de rede com qualidade de serviço. / [en] This work presents a Diffserv architecture study to provide QoS in the Internet. A review of some basic concepts of the main traffic control algorithm and a performance evaluation, through the NS simulation program, is done. In order to get important performance measurement of the QoS network, it was done, for a specific scenario, a study of the queue discipline, queue activity management, with different traffic source.

Infringement in fields of Intellectual Property Rights is a global problem causing repeated and sustained attention at national and international levels. A number of different organizations and commissions are constantly control and counteract the growth of these infringements, but despite the taken measures counterfeit and piracy goods continue to be manufactured and sold around the world. The Russian Federation (RF) is a country that has close commercial ties with many foreign states, including Sweden. However the RF is one of the countries, included on the Special 301 Priority Watch List due to the continuing and large - scale of Property Rights and Intellectual Property Rights violations. In this connection, a study was conducted with the participation of collaborating Swedish - Russian enterprises, whose activities could be subjected to counterfeiting and IP piracy. The aim of the study is to determine how collaborating Swedish – Russian enterprises with branches in the Russian Federation perceive the situation in the country and assess the activities of Russian institutions that play an important role in controlling and combating violations against counterfeiting and IP piracy. Moreover the aim includes identifying the most vulnerable class of actors in the general mechanism of counterfeiting and IP piracy. The research based on elements of the New Institutional Economics Theory and conducted by using a combination of a literature review and semi- structured interview with representatives of Swedish - Russian enterprises. The study found that organizations are the most vulnerable class of actors in general mechanism of counterfeiting and IP piracy. International firms and companies are in a more difficult situation because they provide own activities simultaneously in several legal and political systems. Representatives of interviewed companies argue that activities of analyzed Russian institutions are insufficiently effective and the state should take a set of measures so the foreign collaborative organizations could feel confident in territory of the RF and Russian market would become more attractive for foreign business.