BAMoL Formalização da linguagem e validação sintática de modelos

A BAMoL (Business Application Modeling Language) é uma linguagem de domínio específico utilizada para o desenvolvimento de soluções para a plataforma myMIS, no âmbito dos sistemas de informação para a gestão. Esta linguagem carecia de dois aspetos, nomeadamente a sua formalização e a existência de mecanismos de validação sintática das soluções desenvolvidas. Estes problemas identificados tornam impossível a validação sintática das soluções desenvolvidas utilizando esta linguagem, aumentando assim a probabilidade de existência de erros, podendo fazer com que as mesmas sejam mais ineficientes e podendo até trazer um aumento de custos de manutenção da plataforma. De forma a resolver os problemas enunciados, foi realizada, para o primeiro, uma descrição textual de todos os constituintes da linguagem e criada uma gramática representativa da mesma, em que constam todos os seus elementos e regras. No caso do segundo problema, a sua resolução passou pela criação de uma ferramenta que utiliza a gramática criada e que permite validar sintaticamente e encontrar as falhas das soluções desenvolvidas. Desta forma, passa a ser possível detetar os erros existentes nas soluções, permitindo assim à equipa de desenvolvimento ter maior controlo sobre as mesmas, podendo torná-las mais corretas, na perspetiva das regras da linguagem.

Contributo para a utilização de modelos de simulação dinâmica no dimensionamento de processos de lamas activadas

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Sanitária

Modelação numérica de modelos experimentais de alvenaria de pedra tradicional

Dissertação apresentada para obtenção do grau de Mestre em Engenharia Civil – Perfil de Construção, pela Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa

Modelos de avaliação da qualidade do atendimento na prestação de serviços públicos: aplicação da metodologia de scoping review à tomada de decisão com base na evidência (evidence-based management), na Administração Pública.

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

Um middleware independente da plataforma para computação paralela

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Propagação de vírus informáticos baseada em modelos biológicos

A evolução digital proporcionou às sociedades uma facilidade extraordinária de comunicação. Com o número crescente de computadores e o aumento de acessos à internet, surgiu uma nova forma de criminologia, que cresceu em paralelo com o número de utilizadores. Desta forma, tornou-se comum a criação e difusão de vírus informáticos pelos chamados hackers. Neste trabalho estudam-se modelos de transmissão de vírus informáticos, usando modelos epidemiológicos. Começa-se por fazer uma revisão dos modelos existentes na literatura, de seguida sugerem-se alterações a esses modelos de forma a conseguir uma melhor aproximação à dinâmica real de transmissão de vírus informáticos. As simulações numéricas dos modelos permitem-nos inferir de que uma forma de controlar a transmissão de vírus informáticos é a diminuição da taxa de infeção, isto é, da taxa de transmissão do vírus. No último capítulo enumeram-se as conclusões do trabalho efetuado e indicam-se direções de trabalho futuro.

Electricity markets modeling considering complex contracts and aggregators

All over the world, the liberalization of electricity markets, which follows different paradigms, has created new challenges for those involved in this sector. In order to respond to these challenges, electric power systems suffered a significant restructuring in its mode of operation and planning. This restructuring resulted in a considerable increase of the electric sector competitiveness. Particularly, the Ancillary Services (AS) market has been target of constant renovations in its operation mode as it is a targeted market for the trading of services, which have as main objective to ensure the operation of electric power systems with appropriate levels of stability, safety, quality, equity and competitiveness. In this way, with the increasing penetration of distributed energy resources including distributed generation, demand response, storage units and electric vehicles, it is essential to develop new smarter and hierarchical methods of operation of electric power systems. As these resources are mostly connected to the distribution network, it is important to consider the introduction of this kind of resources in AS delivery in order to achieve greater reliability and cost efficiency of electrical power systems operation. The main contribution of this work is the design and development of mechanisms and methodologies of AS market and for energy and AS joint market, considering different management entities of transmission and distribution networks. Several models developed in this work consider the most common AS in the liberalized market environment: Regulation Down; Regulation Up; Spinning Reserve and Non-Spinning Reserve. The presented models consider different rules and ways of operation, such as the division of market by network areas, which allows the congestion management of interconnections between areas; or the ancillary service cascading process, which allows the replacement of AS of superior quality by lower quality of AS, ensuring a better economic performance of the market. A major contribution of this work is the development an innovative methodology of market clearing process to be used in the energy and AS joint market, able to ensure viable and feasible solutions in markets, where there are technical constraints in the transmission network involving its division into areas or regions. The proposed method is based on the determination of Bialek topological factors and considers the contribution of the dispatch for all services of increase of generation (energy, Regulation Up, Spinning and Non-Spinning reserves) in network congestion. The use of Bialek factors in each iteration of the proposed methodology allows limiting the bids in the market while ensuring that the solution is feasible in any context of system operation. Another important contribution of this work is the model of the contribution of distributed energy resources in the ancillary services. In this way, a Virtual Power Player (VPP) is considered in order to aggregate, manage and interact with distributed energy resources. The VPP manages all the agents aggregated, being able to supply AS to the system operator, with the main purpose of participation in electricity market. In order to ensure their participation in the AS, the VPP should have a set of contracts with the agents that include a set of diversified and adapted rules to each kind of distributed resource. All methodologies developed and implemented in this work have been integrated into the MASCEM simulator, which is a simulator based on a multi-agent system that allows to study complex operation of electricity markets. In this way, the developed methodologies allow the simulator to cover more operation contexts of the present and future of the electricity market. In this way, this dissertation offers a huge contribution to the AS market simulation, based on models and mechanisms currently used in several real markets, as well as the introduction of innovative methodologies of market clearing process on the energy and AS joint market. This dissertation presents five case studies; each one consists of multiple scenarios. The first case study illustrates the application of AS market simulation considering several bids of market players. The energy and ancillary services joint market simulation is exposed in the second case study. In the third case study it is developed a comparison between the simulation of the joint market methodology, in which the player bids to the ancillary services is considered by network areas and a reference methodology. The fourth case study presents the simulation of joint market methodology based on Bialek topological distribution factors applied to transmission network with 7 buses managed by a TSO. The last case study presents a joint market model simulation which considers the aggregation of small players to a VPP, as well as complex contracts related to these entities. The case study comprises a distribution network with 33 buses managed by VPP, which comprises several kinds of distributed resources, such as photovoltaic, CHP, fuel cells, wind turbines, biomass, small hydro, municipal solid waste, demand response, and storage units.

Estimação de Modelos de Adopção e Difusão de Tecnologias de Informação e Comunicação em Portugal

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

A framework for memory contention analysis in multi-core platforms

The last decade has witnessed a major shift towards the deployment of embedded applications on multi-core platforms. However, real-time applications have not been able to fully benefit from this transition, as the computational gains offered by multi-cores are often offset by performance degradation due to shared resources, such as main memory. To efficiently use multi-core platforms for real-time systems, it is hence essential to tightly bound the interference when accessing shared resources. Although there has been much recent work in this area, a remaining key problem is to address the diversity of memory arbiters in the analysis to make it applicable to a wide range of systems. This work handles diverse arbiters by proposing a general framework to compute the maximum interference caused by the shared memory bus and its impact on the execution time of the tasks running on the cores, considering different bus arbiters. Our novel approach clearly demarcates the arbiter-dependent and independent stages in the analysis of these upper bounds. The arbiter-dependent phase takes the arbiter and the task memory-traffic pattern as inputs and produces a model of the availability of the bus to a given task. Then, based on the availability of the bus, the arbiter-independent phase determines the worst-case request-release scenario that maximizes the interference experienced by the tasks due to the contention for the bus. We show that the framework addresses the diversity problem by applying it to a memory bus shared by a fixed-priority arbiter, a time-division multiplexing (TDM) arbiter, and an unspecified work-conserving arbiter using applications from the MediaBench test suite. We also experimentally evaluate the quality of the analysis by comparison with a state-of-the-art TDM analysis approach and consistently showing a considerable reduction in maximum interference.

Trade-Off Performance Regions of Slotted ALOHA Protocol using Multi-Objective Optimization

10th Conference on Telecommunications (Conftele 2015), Aveiro, Portugal.

A Random Access Protocol incorporating Multi-Packet Reception, Retransmission Diversity and Successive Interference Cancellation

8th International Workshop on Multiple Access Communications (MACOM2015), Helsinki, Finland.

Multi-Objective and Financial Portfolio Optimization of Carrier-Sense Multiple Access Protocols with Cooperative Diversity

8th International Workshop on Multiple Access Communications (MACOM2015), Helsinki, Finland.

System Level Simulation and Radio Resource Management for Distributed Antenna Systems with Cognitive Radio and Multi-Cell Cooperation

4th International Conference on Future Generation Communication Technologies (FGCT 2015), Luton, United Kingdom.

A Multi-DAG Model for Real-Time Parallel Applications with Conditional Execution

The 30th ACM/SIGAPP Symposium On Applied Computing (SAC 2015). 13 to 17, Apr, 2015, Embedded Systems. Salamanca, Spain.