Esta dissertação de mestrado apresenta a prototipação de uma arquitetura denominada ServidorWeb com Diferenciação de Serviços (SWDS). O trabalho também apresenta a proposta, implementação e a avaliação de desempenho de dois algoritmos de controle de admissão denominados Algoritmo de Negociação e Algoritmo de Reserva de Conexões. O objetivo principal deste trabalho é a avaliação de desempenho dos algoritmos de controle de admissão no protótipo do SWDS. Como resultados, verificou-se que a Classe de maior prioridade consegue atender mais requisições que a Classe de menor prioridade em todos as configurações de carga. Também pode-se observar que o algoritmo de reserva de conexões consegue se adaptar a todas as variações de cargas / This masters dissertation presents the prototype of an architecture named SWDS. This work presents the proposal, implementation and performance evaluation of two admission control algorithms named negotiation algorithm and connection reserve algorithm. The aim of this work is to evaluate the performance of the control admission algorithms in the SWDS prototype. As a result, it could be seen the high priority Class met a higher number of requests than the low priority Class. Also it could be seen the connection reserve algorithm can adapt to all workloads variation

WS-DSAC à uma plataforma desenvolvida sob um cluster de servidores Web com balanceamento de cargas capaz de realizar o controle de admissÃo e diferenciaÃÃo de serviÃos para permitir a diferenciaÃÃo da QoS oferecida aos clientes e utilizar de forma eficaz os recursos disponÃveis. Quando requisiÃÃes em excesso sÃo enviadas para o cluster, o sistema se torna "saturado". Isto significa que o mecanismo de controle de admissÃo nÃo à mais capaz de manter o tempo de resposta necessÃrio para que se possa garantir a qualidade de serviÃo do sistema como um todo. Neste trabalho à apresentado um mecanismo que utiliza o conceito de interrupÃÃo e reativaÃÃo de processos para otimizar a capacidade de processamento do sistema com a finalidade de evitar o problema da "saturaÃÃo". Este mecanismo interrompe apenas os processos que podem ocasionar sobrecarga do servidor e reinicializando-os posteriormente quando a carga do servidor volta a melhores condiÃÃes de processamento. Desta forma, à possÃvel aumentar o nÃmero de requisiÃÃes privilegiadas Ãs expensas de outros serviÃos que podem esperar, diminuindo tambÃm nÃmero de requisiÃÃes nÃo atendidas. / With the expansion of services offered through the Internet and the popularization of the Web technology in the modern world, the toughest problems Web server administrators face are how to dimension infrastructure and how to manage the high workload during intense processing moments. As a result, we have websites with extremely high response times, due to bad resource management. This paper presents a mechanism of high availability for services and process management, for the optimization of server capacity, through a technique called process interruption and restart. The interruption and restart technique was employed to enable services to be available even through high workload moments. The restarts have three important advantages. First, it either makes a process go back to its initial state or become immune to problems. Second, the restarts have the property of increasing system reliability. The suspension and restart technique is utilized to control resource consumption under heavy processing workload. Another advantage is that restarting is a simple mechanism, easy to implement and retrieve. This has created the possibility of creating a new layer that allows better process management under severe workloads. It provides better machine performance, lower response time, and greater service availability, in addition to meeting SLA needs â QoS contracts.

Esta dissertação de mestrado apresenta a prototipação de uma arquitetura denominada ServidorWeb com Diferenciação de Serviços (SWDS). O trabalho também apresenta a proposta, implementação e a avaliação de desempenho de dois algoritmos de controle de admissão denominados Algoritmo de Negociação e Algoritmo de Reserva de Conexões. O objetivo principal deste trabalho é a avaliação de desempenho dos algoritmos de controle de admissão no protótipo do SWDS. Como resultados, verificou-se que a Classe de maior prioridade consegue atender mais requisições que a Classe de menor prioridade em todos as configurações de carga. Também pode-se observar que o algoritmo de reserva de conexões consegue se adaptar a todas as variações de cargas / This masters dissertation presents the prototype of an architecture named SWDS. This work presents the proposal, implementation and performance evaluation of two admission control algorithms named negotiation algorithm and connection reserve algorithm. The aim of this work is to evaluate the performance of the control admission algorithms in the SWDS prototype. As a result, it could be seen the high priority Class met a higher number of requests than the low priority Class. Also it could be seen the connection reserve algorithm can adapt to all workloads variation

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There is a huge demand for analysis and visualization of the biological models. PathwayPioneer is a web-based tool to analyze and visually represent complex biological models. PathwayPioneer generates the initial layout of the model and allows users to customize it. It is developed using .net technologies (C#) and hosted on the Internet Information Service (IIS) server. At back-end it interacts with python-based COBRApy library for biological calculations like Flux Balance Analysis (FBA). We have developed a parallel processing architecture to accommodate processing of large models and enable message-based communication between the .net webserver and python engine. We compared the performance of our online system by loading a website with multiple concurrent dummy users and performed different time intensive operations in parallel. Given two metabolites of interest, millions of pathways can be found between them even in a small metabolic network. Depth First Search or Breadth First search algorithm retrieves all the possible pathways, thereby requiring huge computational time and resources. In Pathway Search using Informed Method, we have implemented, compared, and analyzed three different informed search techniques (Selected Subsystem, Selected Compartment, and Dynamic Search) and traditional exhaustive search technique. We found that the Dynamic approach performs exceedingly well with respect to time and total number of pathways searches. During our implementation we developed a SBML parser which outperforms the commercial libSBML parser in C#.

A MAP/PH/1 queue is a queue having a Markov arrival process (MAP), and a single server with phase-type (PH -type) distributed service time. This thesis considers the departure process from these type of queues. We use matrix analytic methods, the Jordan canonical form of matrices, non-linear filtering and approximation techniques. The departure process of a queue is important in the analysis of networks of queues, as it may be the arrival process to another queue in the network. If a simple description were to exist for a departure process, the analysis of at least feed-forward networks of these queues would then be analytically tractable. Chapter 1 is an introduction to some of the literature and ideas surrounding the departure process from MAP/PH/1 queues. Chapter 2 sets up the basic notation and establishes some results which are used throughout the thesis. It contains a preliminary consideration of PH -type distributions, PH -renewal processes, MAP s, MAP/PH/1 queues, non-linear filtering and the Jordan canonical form. Chapter 3 is an expansion of "The Output process of an MMPP/M/1 queue", where the question of whether a MAP description can exist for the departure process of a non-trivial MAP/M/1 queue is considered. In a 1994 paper, Olivier and Walrand conjectured that the departure process of a MAP/PH/1 queue is not a MAP unless the queue is a stationary M/M/1 queue. This conjecture was prompted by their claim that the departure process of an MMPP/M/1 queue is not MAP unless the queue is a stationary M/M/1 queue. We show that their proof has an algebraic error, which leaves open the above question of whether the departure process of an MMPP/PH/1 queue is a MAP or not. In Chapter 4, the more fundamental problem of identifying stationary M/M/1 queues in the class of MAP/PH/1 queues is considered. It is essential to be able to determine from its generator when a stationary MAP is a Poisson process. This does not appear to have been discussed in the literature prior to the author's paper, where this deficiency was remedied using ideas from non-linear filtering theory, to give a characterisation as to when a stationary MAP is a Poisson process. Chapter 4 expands upon "When is a MAP Poisson". This investigation of higher order representations of the Poisson process is motivated by first considering when a higher order PH -type distribution is just negative exponential. In Chapter 5, we consider the related question of minimal order representations for PH -type distributions, an issue which has attracted much interest in the literature. A discussion of other authors' ideas is given and these ideas are then inter-related to the work presented in Chapter 4 on the PH -type distributions. The MAP/M/1 queue is then considered in Chapter 6 from the perspective of whether having an exact level and phase independent stationary distribution of the geometric form [Formula - Not available: see pdf version of the abstract] implies that the MAP is Poisson. The answer is in the affirmative for this question, but the converse is not strictly true. Apart from showing the ubiquitous asymptotic form of level and phase independence exhibited by all stable MAP/M/1 queues, we prove that a very large class of stable queues, exhibits what we have termed shift-one level and phase independence. Stable MAP/M/1 queues exhibiting shift-one level and phase independence, are characterised by a stationary distribution of the following form: [Formula - Not Available: see pdf version of the abstract] In Chapter 7, a family of approximations is proposed for the output process of a stationary MAP/PH/1 queue. To check the viability of these approximations, they are used as input to another single server queue. Performance measures for the second server are obtained analytically in both the tandem and approximation cases, thus eliminating the need for simulation to compare results. Comparison of these approximations is also made against other approximation methods in the literature. In Chapter 8, we show that our approximations from Chapter 7 have the property of exactly matching the inter-departure time distribution. Our kth approximation also accurately captures the first k-1 lag-correlation coefficients of the stationary departure process. The proofs of this direct association between lag-correlation coefficients and the level of complexity k are given. / Thesis (Ph.D.)--School of Applied Mathematics, 1999.

In recent years, new visualisation techniques and devices, such as remote visualisation and stereoscopic displays, have been developed to help researchers. In a remote visualisation environment the user may want to see visualisation on a different device, such as a PDA or stereo device, and in different circumstances. Each device needs to be configured correctly, otherwise it may lead to an incorrect rendering of the output. For end users, however, it can be difficult to configure each device without a knowledge of the device property and rendering. Therefore, in a multiple user and multiple display environment, to obtain the correct display for each device can be a challenge. In this project, the focus on investigating a solution that can support end users to use different display devices easily. The proposed solution is to develop an application that can support the ad-hoc use of any display device without the system being preconfigured in advance. Thus, end users can obtain the correct visualisation output without any complex rendering configuration. We develop a client-server based approach to this problem. The client application can detect the properties of a device and the server application can use these properties to configure the rendering software to generate the correct image for subsequent display on the device. The approach has been evaluated through many tests and the results show that using the application is a useful in helping end users use different display devices in visualisation.

<p>Server-based architectures have recently generated more interests and are currently considered for usage for communication in networks. In parallel, switched Ethernet technology has been widely adopted and used in lots of networked systems. Current requirements of networks for supporting real-time guarantees while being flexible at the same time have made the network designers to consider addition of some features to common switches. The FTT-Enabled Ethernet switch is a switch that has been developed to support the FTT (Flexible Time Triggered) paradigm. Recently, servers have been added in these types of switches in order to efficiently manage their allocated bandwidth to different types of messages.</p><p>A hierarchical network of Ethernet switches might be designed in different ways according to the overall goals and properties of the network. In this thesis, after a study on different design solutions, an architecture has been proposed based on FTT-enabled switches, motivated by their support of real-time constraints and server-based communication features. After having created the architecture, a protocol for bandwidth reservation for this hierarchically composed Ethernet switch architecture is developed. Behavior of the designed protocol is described in detail and it has been modeled using Uppaal. Moreover, the temporal behavior (timing) of the network is presented.</p>

<p>This master’s thesis was performed at PartnerTech AB in Åtvidaberg. It addresses the problem of managing test results obtained from testing electronics manufactured by PartnerTech. PartnerTech has developed a test system, called Tor, which performs tests on manufactured boards and stores the test results in files. The Tor system consists of both hardware and software part, where the software runs on an ordinary PC with MS DOS/Windows 2000. The effects on the existing Tor system that this thesis implies are minimal. </p><p>This work focuses on a way of storing the produced test files in a database. In this work a data model has been developed, implemented, and evaluated together with a system that imports test files into the database and a graphical user interface that allows a user to easily search and browse the stored test results. It is also possible to print test reports from the Tor system. For implementing the database system Microsoft SQL Server 2000 was chosen as database server and an XML based data format was chosen to import and export data to and from the database. Two alternative graphical user interface applications were developed and compared - one server based on Microsoft IIS and one client based in Microsoft Access. For advanced data manipulation certain parts of the system were developed in Microsoft Excel.</p>

<p>Report writers (sv rapporteringsverktyg) används för att skapa och hantera databasbaserade rapporter. Detta examensarbete handlar om Reporting Services, ett helt nytt rapporteringsverktyg från Microsoft. Syftet med examensarbetet var att utvärdera Reporting Services för att se vad verktyget har att erbjuda i förhållande till rapporteringsverktyg från andra tillverkare. En jämförelse mellan Reporting Services och rapporteringsverktyg från tre andra betydande tillverkare har gjorts. En djupare utvärdering av Reporting Services, där arkitektur, funktionalitet och andra egenskaper gåtts igenom grundligt, har också genomförts. Arbetet har visat att problemet att jämföra olika rapporteringsverktyg med varandra är ganska komplext och att olika verktyg lämpar sig olika bra i olika situationer och kontexter. Verktygens arkitektur skiljer sig åt och de erbjuder olika funktionalitet. Arbetet har också visat att Reporting Services definitivt är ett bra alternativ för företag som använder SQL Server, inte minst ur ekonomisk synvinkel. Verktyget ger användarna en god kontroll över utformningen av rapporter, det är lätt att exportera rapporter till olika format och det finns flera bra möjligheter att distribuera rapporter till läsare.</p>