Modelos de simula����o em MATSim aplicados �� an��lise de sistemas de transporte

Disserta����o para obten����o do grau de Mestre em Engenharia Civil na ��rea de Especializa����o de Vias de Comunica����o e Transportes

Cooperative framework for open real-time systems

Actualmente, os sistemas embebidos est��o presentes em toda a parte. Embora grande parte da popula����o que os utiliza n��o tenha a no����o da sua presen��a, na realidade, se repentinamente estes sistemas deixassem de existir, a sociedade iria sentir a sua falta. A sua utiliza����o massiva deve-se ao facto de estarem practicamente incorporados em quase os todos dispositivos electr��nicos de consumo, telecomunica����es, automa����o industrial e autom��vel. Influenciada por este crescimento, a comunidade cient��fica foi confrontada com novos problemas distribu��dos por v��rios dom��nios cient��ficos, dos quais s��o destacados a gest��o da qualidade de servi��o e gest��o de recursos - dom��nio encarregue de resolver problemas relacionados com a aloca����o ��ptima de recursos f��sicos, tais como rede, mem��ria e CPU. Existe na literatura um vasto conjunto de modelos que prop��em solu����es para v��rios problemas apresentados no contexto destes dom��nios cient��ficos. No entanto, n��o �� poss��vel encontrar modelos que lidem com a gest��o de recursos em ambientes de execu����o cooperativos e abertos com restri����es temporais utilizando coliga����es entre diferentes n��s, de forma a satisfazer os requisitos n��o funcionais das aplica����es. Devido ao facto de estes sistemas serem din��micos por natureza, apresentam a caracter��stica de n��o ser poss��vel conhecer, a priori, a quantidade de recursos necess��rios que uma aplica����o ir�� requerer do sistema no qual ir�� ser executada. Este conhecimento s�� �� adquirido aquando da execu����o da aplica����o. De modo a garantir uma gest��o eficiente dos recursos dispon��veis, em sistemas que apresentam um grande dinamismo na execu����o de tarefas com e sem restri����es temporais, �� necess��rio garantir dois aspectos fundamentais. O primeiro est�� relacionado com a obten����o de garantias na execu����o de tarefas de tempo-real. Estas devem sempre ser executadas dentro da janela temporal requirida. O segundo aspecto refere a necessidade de garantir que todos os recursos necess��rios �� execu����o das tarefas s��o fornecidos, com o objectivo de manter os n��veis de performance quer das aplica����es, quer do pr��prio sistema. Tendo em conta os dois aspectos acima mencionados, o projecto CooperatES foi especificado com o objectivo de permitir a dispositivos com poucos recursos uma execu����o colectiva de servi��os com os seus vizinhos, de modo a cumprir com as complexas restri����es de qualidade de servi��o impostas pelos utilizadores ou pelas aplica����es. Decorrendo no contexto do projecto CooperatES, o trabalho resultante desta tese tem como principal objectivo avaliar a practicabilidade dos conceitos principais propostos no ��mbito do projecto. O trabalho em causa implicou a escolha e an��lise de uma plataforma, a an��lise de requisitos, a implementa����o e avalia����o de uma framework que permite a execu����o cooperativa de aplica����es e servi��os que apresentem requisitos de qualidade de servi��o. Do trabalho desenvolvido resultaram as seguintes contribui����es: An��lise das plataformas de c��digo aberto que possam ser utilizadas na implementa����o dos conceitos relacionados com o projecto CooperatES; Crit��rios que influenciaram a escolha da plataforma Android e um estudo focado na an��lise da plataforma sob uma perspectiva de sistemas de tempo-real; Experi��ncias na implementa����o dos conceitos do projecto na plataforma Android; Avalia����o da practicabilidade dos conceitos propostos no projecto CooperatES; Proposta de extens��es que permitam incorporar caracter��sticas de sistemas de tempo real abertos na plataforma Android.

Framework de controlo de acessos para Triple-stores com interface Sail API

Grande parte dos triples-stores s��o open source e desenvolvidos em Java, disponibilizando interfaces standards e privadas de acesso. A grande maioria destes sistemas n��o disp��e de mecanismos de controlo de acessos nativos, o que dificulta ou impossibilita a sua adop����o em ambientes em que a seguran��a dos factos �� importante (e.g. ambiente empresarial). Complementarmente observa-se que o modelo de controlo de acesso a triplos e em particular a triplos descritos por ontologias n��o est�� standardizado nem sequer estabilizado, havendo diversos modelos de descri����o e algoritmos de avalia����o de permiss��es de acesso. O trabalho desenvolvido nesta tese/disserta����o prop��e um modelo e interface de controlo de acesso que permite e facilite a sua adop����o por diferentes triple-stores j�� existentes e a integra����o dos triples-stores com outros sistemas j�� existentes na organiza����o. Complementarmente, a plataforma de controlo de acesso n��o imp��e qualquer modelo ou algoritmo de avalia����o de permiss��es, mas pelo contr��rio permite a adop����o de modelos e algoritmos distintos em fun����o das necessidades ou desejos. Finalmente demonstra-se a aplicabilidade e validade do modelo e interface propostos, atrav��s da sua implementa����o e adop����o ao triple-store SwiftOWLIM j�� existente, que n��o disp��e de mecanismo de controlo de acessos nativo.

Edi����o gr��fica de layout fabril no apoio ao planeamento e controlo da produ����o

O contributo da ��rea de investiga����o Interac����o Humano-Computador (HCI) est�� patente n��o s�� na qualidade da interac����o, mas tamb��m na diversifica����o das formas de interac����o. A HCI define-se como sendo uma disciplina que se dedica ao desenho, desenvolvimento e implementa����o de sistemas de computa����o interactivos para uso humano e estudo dos fen��menos relevantes que os rodeiam. Pretende-se, no ��mbito desta tese de mestrado, o desenvolvimento de um Editor Gr��fico de Layout Fabril a integrar num SAD para suporte ao Planeamento e Controlo da Produ����o. O sistema deve ser capaz de gerar um layout fabril do qual constam, entre outros objectos, as representa����es gr��ficas e as respectivas caracter��sticas/atributos do conjunto de recursos (m��quinas/processadores) existentes no sistema de produ����o a modelar. O m��dulo desenvolvido ser�� integrado no projecto de I&D ADSyS (Adaptative Decision Support System for Interactive Scheduling with MetaCognition and User Modeling Experience), melhorando aspectos de interac����o referentes ao sistema AutoDynAgents, um dedicado ao escalonamento, planeamento e controlo de produ����o. Foi realizada a an��lise de usabilidade a este m��dulo com a qual se pretendeu realizar a respectiva avalia����o, atrav��s da realiza����o de um teste de efici��ncia e do preenchimento de um inqu��rito, da qual se identificaram um conjunto de melhorias e sugest��es a serem consideradas no refinamento deste m��dulo.

To Ada or not To Ada: Adaing vs. Javaing in real-time systems

Ada is really an unfortunate Lady. After years fighting against C/C++ villains, her major lift-up (Ada 95) had brought up a promise of fortune. However, a new strong villain (Java) has appeared trying to end her struggle for survival. Ada has now to fight with her own weapons. She will only prosper by her own merits. But two questions emerge. Do they exist? Are they better than Java���s? Our opinion is that they do exist, and are not matched by any other programming language

Combining RTSJ with Fork/Join: a priority-based model

This paper discusses the increased need to support dynamic task-level parallelism in embedded real-time systems and proposes a Java framework that combines the Real-Time Specification for Java (RTSJ) with the Fork/Join (FJ) model, following a fixed priority-based scheduling scheme. Our work intends to support parallel runtimes that will coexist with a wide range of other complex independently developed applications, without any previous knowledge about their real execution requirements, number of parallel sub-tasks, and when those sub-tasks will be generated.

Experiences on the implementation of a cooperative embedded system framework

As the complexity of embedded systems increases, multiple services have to compete for the limited resources of a single device. This situation is particularly critical for small embedded devices used in consumer electronics, telecommunication, industrial automation, or automotive systems. In fact, in order to satisfy a set of constraints related to weight, space, and energy consumption, these systems are typically built using microprocessors with lower processing power and limited resources. The CooperatES framework has recently been proposed to tackle these challenges, allowing resource constrained devices to collectively execute services with their neighbours in order to fulfil the complex Quality of Service (QoS) constraints imposed by users and applications. In order to demonstrate the framework's concepts, a prototype is being implemented in the Android platform. This paper discusses key challenges that must be addressed and possible directions to incorporate the desired real-time behaviour in Android.

Autonomic workflow activities: the award framework

Workflows have been successfully applied to express the decomposition of complex scientific applications. This has motivated many initiatives that have been developing scientific workflow tools. However the existing tools still lack adequate support to important aspects namely, decoupling the enactment engine from workflow tasks specification, decentralizing the control of workflow activities, and allowing their tasks to run autonomous in distributed infrastructures, for instance on Clouds. Furthermore many workflow tools only support the execution of Direct Acyclic Graphs (DAG) without the concept of iterations, where activities are executed millions of iterations during long periods of time and supporting dynamic workflow reconfigurations after certain iteration. We present the AWARD (Autonomic Workflow Activities Reconfigurable and Dynamic) model of computation, based on the Process Networks model, where the workflow activities (AWA) are autonomic processes with independent control that can run in parallel on distributed infrastructures, e. g. on Clouds. Each AWA executes a Task developed as a Java class that implements a generic interface allowing end-users to code their applications without concerns for low-level details. The data-driven coordination of AWA interactions is based on a shared tuple space that also enables support to dynamic workflow reconfiguration and monitoring of the execution of workflows. We describe how AWARD supports dynamic reconfiguration and discuss typical workflow reconfiguration scenarios. For evaluation we describe experimental results of AWARD workflow executions in several application scenarios, mapped to a small dedicated cluster and the Amazon (Elastic Computing EC2) Cloud.

Plataforma para testes de conformidade de sistemas baseados em m��dulos conceptuais STEP

Obten����o do grau de Mestre em Engenharia Electrot��cnica, Sistemas e Computadores

Penalty fuzzy function for derivative-free optimization

Penalty and Barrier methods are normally used to solve Nonlinear Optimization Problems constrained problems. The problems appear in areas such as engineering and are often characterised by the fact that involved functions (objective and constraints) are non-smooth and/or their derivatives are not know. This means that optimization methods based on derivatives cannot net used. A Java based API was implemented, including only derivative-free optimizationmethods, to solve both constrained and unconstrained problems, which includes Penalty and Barriers methods. In this work a new penalty function, based on Fuzzy Logic, is presented. This function imposes a progressive penalization to solutions that violate the constraints. This means that the function imposes a low penalization when the violation of the constraints is low and a heavy penalisation when the violation is high. The value of the penalization is not known in beforehand, it is the outcome of a fuzzy inference engine. Numerical results comparing the proposed function with two of the classic penalty/barrier functions are presented. Regarding the presented results one can conclude that the prosed penalty function besides being very robust also exhibits a very good performance.

Direct search optimization application programming interface with remote access

Search Optimization methods are needed to solve optimization problems where the objective function and/or constraints functions might be non differentiable, non convex or might not be possible to determine its analytical expressions either due to its complexity or its cost (monetary, computational, time,...). Many optimization problems in engineering and other fields have these characteristics, because functions values can result from experimental or simulation processes, can be modelled by functions with complex expressions or by noise functions and it is impossible or very difficult to calculate their derivatives. Direct Search Optimization methods only use function values and do not need any derivatives or approximations of them. In this work we present a Java API that including several methods and algorithms, that do not use derivatives, to solve constrained and unconstrained optimization problems. Traditional API access, by installing it on the developer and/or user computer, and remote API access to it, using Web Services, are also presented. Remote access to the API has the advantage of always allow the access to the latest version of the API. For users that simply want to have a tool to solve Nonlinear Optimization Problems and do not want to integrate these methods in applications, also two applications were developed. One is a standalone Java application and the other a Web-based application, both using the developed API.

A web-based tool to evaluate the iterative processes of direct search methods

Constrained and unconstrained Nonlinear Optimization Problems often appear in many engineering areas. In some of these cases it is not possible to use derivative based optimization methods because the objective function is not known or it is too complex or the objective function is non-smooth. In these cases derivative based methods cannot be used and Direct Search Methods might be the most suitable optimization methods. An Application Programming Interface (API) including some of these methods was implemented using Java Technology. This API can be accessed either by applications running in the same computer where it is installed or, it can be remotely accessed through a LAN or the Internet, using webservices. From the engineering point of view, the information needed from the API is the solution for the provided problem. On the other hand, from the optimization methods researchers��� point of view, not only the solution for the problem is needed. Also additional information about the iterative process is useful, such as: the number of iterations; the value of the solution at each iteration; the stopping criteria, etc. In this paper are presented the features added to the API to allow users to access to the iterative process data.

Web-based application programming interface to solve nonlinear optimization problems

Nonlinear Optimization Problems are usual in many engineering fields. Due to its characteristics the objective function of some problems might not be differentiable or its derivatives have complex expressions. There are even cases where an analytical expression of the objective function might not be possible to determine either due to its complexity or its cost (monetary, computational, time, ...). In these cases Nonlinear Optimization methods must be used. An API, including several methods and algorithms to solve constrained and unconstrained optimization problems was implemented. This API can be accessed not only as traditionally, by installing it on the developer and/or user computer, but it can also be accessed remotely using Web Services. As long as there is a network connection to the server where the API is installed, applications always access to the latest API version. Also an Web-based application, using the proposed API, was developed. This application is to be used by users that do not want to integrate methods in applications, and simply want to have a tool to solve Nonlinear Optimization Problems.

Virtual laboratory for educational environments

In this paper a new simulation environment for a virtual laboratory to educational proposes is presented. The Logisim platform was adopted as the base digital simulation tool, since it has a modular implementation in Java. All the hardware devices used in the laboratory course was designed as components accessible by the simulation tool, and integrated as a library. Moreover, this new library allows the user to access an external interface. This work was motivated by the needed to achieve better learning times on co-design projects, based on hardware and software implementations, and to reduce the laboratory time, decreasing the operational costs of engineer teaching. Furthermore, the use of virtual laboratories in educational environments allows the students to perform functional tests, before they went to a real laboratory. Moreover, these functional tests allow to speed-up the learning when a problem based approach methodology is considered. �� 2014 IEEE.

Comanche: aplica����es web estendidas nos clientes

Disserta����o apresentada na Faculdade de Ci��ncias e Tecnologia da Universidade Nova de Lisboa para obten����o do grau de Mestre em Engenharia Inform��tica