Este trabalho de pesquisa apresenta um protótipo de servidor Web distribuído com diferenciação de serviços baseado em QoS relativa e absoluta. São implementados e comparados diferentes algoritmos de escalonamento. Um dos algoritmos avaliados é o EBS. O objetivo é transpor a teoria da política para o mundo real, e comparar o seu comportamento com os resultados das simulações, utilizando o tempo de resposta como medida de desempenho. Além do EBS, outros algoritmos são avaliados, tais como, Round-Roubin e Weighted Round Robin / This work presents a prototype of a distributed Web server with service differentiation based on relative and absolute QoS. Are compared different schedule algorithms. One of the policies to be evaluated is the EBS. The goal is to implement the policy theory to the real world, comparing their behavior with the simulation results, using the response time as a performance measure. In addition to the EBS, others policies are evaluated, such as Round-Roubin and Weight Round Robin

This paper is an all-embracing introduction to HTTP performance, which encompasses all areas of importance concerning application layer performance. We highlight seven areas to consider before implementing HTTP/1.1 in an embedded web server, these were identified by a careful survey of previous research. The highlighted topics are the new request methods, persistent connections, chunked encoding, byte- range operations, content negotiation, digest authentication and caching, all new or improved features in HTTP/1.1. We explore why the old design rationale of HTTP/1.1 has become obsolete in an embedded setting. We also suggest new guidelines which are more suitable for an embedded web server. / Hannes Persson, hannes.persson@mac.com Christian Toft, mda00cto@student.bth.se

This document contains basic principles and processes regarding secure access to web information system. It consists of theoretic and applied part. These are mainly written together in thesis’s chapters. Theoretic informations were tested on simple web application created in PHP computer language on Apache web server using MySQL database. In the beginning, there is an analysis of used programming environment, especially it’s advantages and disadvantages. The main part of this document is simple characterization of many security problems which can be found on many websites all around the world. In the first place it’s a handling problem of inputs and outputs in the web applications. Password disputableness is solving separatelly. Theory of a problem is analysed first of all. Then a couple of solving methods are suggested and the one which is practically realized is described in detail. There is a notification system created which is used to inform user about errors appeared in web application. In the last section there is a client and server certificates described. This document contains fully characterization of used scripts and connection between them. They are supplemented with many pictures and screenshots which are used to better understanding the disputableness of web security.

The main objective of this work is created using Raspberry Pi intelligent garden. The first part is devoted to the concept of intelligent building. The second part describes the used hardware components. Another section is devoted SW Raspberry microcomputer and microcontroller Arduino. The last chapter describes the implemented model of a intelligent garden.

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No / Over the last few years, cloud computing has become quite popular. It offers Web-based companies the advantage of scalability. However, this scalability adds complexity which makes analysis and predictable performance difficult. There is a growing body of research on load balancing in cloud data centres which studies the problem from the perspective of the cloud provider. Nevertheless, the load balancing of scalable web servers deployed on the cloud has been subjected to less research. This paper introduces a simple queueing model to analyse the performance metrics of web server under varying traffic loads. This assists web server managers to manage their clusters and understand the trade-off between QoS and cost. In this proposed model two thresholds are used to control the scaling process. A discrete-event simulation (DES) is presented and validated via an analytical solution.

The structures obtained from homology modeling methods are of intermediate resolution 1-3Ã… from true structure. Energy minimization methods allow us to refine the proteins and obtain native like structures. Previous work shows that some of these methods performed well on soluble proteins. So we extended this work on membrane proteins. Prediction of membrane protein structures is a particularly important, since they are important biological drug targets, and since their number is vanishingly small, as a result of the inherent difficulties in working with these molecules experimentally. Hence there is a pressing need for alternative computational protein structure prediction methods. This work tests the ability of common molecular mechanics potential functions (AMBER99/03) and a hybrid knowledge-based potential function (KB_0.1) to refine near-native structures of membrane proteins in vacuo. A web based utility for protein refinement has been developed and deployed based on the KB_0.1 potential to refine proteins.

Esta dissertação de mestrado aborda a introdução de reconhecimento de sessões http em um modelo de servidor web com serviços diferenciados (SWDS). Algumas técnicas foram desenvolvidas com o objetivo de produzir diferenciação de serviços junto com garantias de que novas sessões poderiam ser aceitas no sistema. Esses objetivos constituem requisitos essenciais na Internet atual, especialmente para aplicações web modernas. Um novo esquema para controle de admissão de sessões foi desenvolvido e introduzido no modelo SWDS, considerando dois mecanismos para aceitar novas sessões, com garantia de nalização. O mecanismo que estima a capacidade do sistema de aceitar novas sessões, baseado em um modelo de sessão construído dinamicamente a partir da carga do sistema, é destacado. A proposta global deste trabalho também considera um controle de admissão de requisições, baseado em sessões, onde a nova política de atendimento criada mantém o sistema livre de sobrecargas e oferece atendimento diferenciado para as sessões. As políticas de negociação desenvolvidas para o controle de admissão de requisições tiveram um papel importante neste trabalho, contribuindo para a priorização do atendimento das sessões. Os resultados obtidos mostram que os controles propostos constituem estruturas fundamentais para a estabilidade do desempenho do sistema, tanto quanto os mecanismos desenvolvidos têm grande importância no atendimento das sessões e, portanto de seus clientes, através de uma abordagem baseada em diferenciação. / This MSc dissertation approaches the introduction of the HTTP sessions recognition in a web server model with diferentiated services (SWDS). Some techniques have been developed aiming at issuing diferentiation of services together with guarantees that new sessions could be accepted in the system. These aims constitute essential requirements for the current Internet, especially for modern web applications. A new scheme for the admission control system has been developed and introduced in the SWDS model, considering two mechanisms for accepting new sessions, with guarantee of their nalizations. The mechanism that estimates the system capacity of acceptance of a new session, based on a session model built dynamically from system workload information, is highlighted. The global propose of this work also considers a request admission control, based on sessions, where the new attendance polices created keep the system free from overloads and over diferentiated attendance for the sessions. The negotiation polices developed for request admission control had an important place in this work, contributing for the session attendance prioritization. The results reached show that the controls proposed comprise fundamental structures for system performance stability, as well as the mechanisms developed have great importance in attending sessions and, therefore, their clients by means of a diferentiation-based approach.

A World Wide Web é um meio de comunicação em constante crescimento, agregando diversos componentes e serviços em um ritmo acelerado. Os novos tipos de sites, tais como, o comércio eletrônico (e-commerce), notí?cia/informação (Web-publishing), vídeo sob demanda exigem ainda mais recursos do servidor. Nesse contexto, visando adequar a avaliação de desempenho aos novos ambientes da Web, o presente trabalho apresenta um estudo caracterizando diversos traces de servidores Web Apache, permitindo coletar dados importantes que definem a forma como os usuários e servidores interagem. Com esses dados, quatro tipos de categorias de sites foram analisados: Padrão (composto da média de todos os traces analisados), Acadêmico, Notícia/Informação e Tradicional. Nessa análise avaliam-se quatro aspectos: o intervalo de chegada, o código de resposta, o tipo objeto e o tamanho do objeto e ao final, modelos matemáticos são propostos para representar essas características. Além disso, este trabalho também desenvolveu um gerador de cargas de trabalho sintéticas, o W4Gen(World Wide Web Workload Generator). Com uma interface gráfica amigável, ele permite aos seus usuários gerar novas cargas com base nos modelos matemáticos. Além disso, ele também permite modificar as características essenciais para simular novos tipos de cargas. Para validar os resultados deste trabalho, utilizou-se o modelo de servidor Web com diferenciação de serviços (SWDS), verificando o desempenho em situações de sobregarga / World Wide Web is a media in constant growth, joining several components and services in an accelerated evolution. The new kinds of sites, such as, E-commerce, Web-publishing and demand video still uses more servers resources. In this context, adapting the newWeb environment to performance evaluation, the present work accomplished a characterization study of several Apache Web servers traces, allowing collect important data that define the form as users and servers interact. With these data, four types of sites categories were analyzed: Default (composed of all trace), Academic, Web-publishing and Traditional. In this analysis, it was evaluated four aspects: the arrival time, the status code, the object class and the object size and at the end, mathematical models are proposed to represent those characteristics. Furthermore, a synthetic workload generator was also developed. With a graphical interface, the W4Gen (World WideWebWorkload Generator), as called, allows the users to generate new workloads based on mathematical models. Besides, it also allows to modify the four essential aspects preseted above to simulate new types of workloads. Finally, to validate the results, the Web server model with differentiated services was used, verifying the performance in overload situations

Esta dissertação apresenta a construção de um protótipo de servidor Web distribuído, baseado no modelo de servidor Web com diferenciação de serviços (SWDS) e a implementação e avaliação de algoritmos de seleção, utilizando o conceito de controle de congestionamento para requisições HTTP. Com isso, além de implementar uma plataforma de testes, este trabalho também avalia o comportamento de dois algoritmos de controle de congestionamento. Os dois algoritmos estudados são chamados de Drop Tail e RED (Random Early Detection), no qual são bastante difundidos na literatura científica e aplicados em redes de computadores. Os resultados obtidos demostram que, apesar das particularidades de cada algoritmo, existe uma grande relação entre tempo de resposta e a quantidade de requisições aceitas / This MSc dissertation presents the implementation of a prototype for a distributed web server based on the SWDS, a model for a web server with service differentiation, and the implementation and evaluation of selection algorithms adopting the concept of congestion control for HTTP requests. Thus, besides implementing a test platform this work also evaluates the behavior of two congestion control algorithms. The two algorithms studied are the Drop Tail and the RED (Random Early Detection), which are frequently discussed in the scientific literature and widely applied in computer networks. The results obtained show that, although the particularities of each algorithm, there is a strong relation between the response times and the amount of requests accepted in the server