Direct multisearch for multiobjective optimization

In practical applications of optimization it is common to have several conflicting objective functions to optimize. Frequently, these functions are subject to noise or can be of black-box type, preventing the use of derivative-based techniques. We propose a novel multiobjective derivative-free methodology, calling it direct multisearch (DMS), which does not aggregate any of the objective functions. Our framework is inspired by the search/poll paradigm of direct-search methods of directional type and uses the concept of Pareto dominance to maintain a list of nondominated points (from which the new iterates or poll centers are chosen). The aim of our method is to generate as many points in the Pareto front as possible from the polling procedure itself, while keeping the whole framework general enough to accommodate other disseminating strategies, in particular, when using the (here also) optional search step. DMS generalizes to multiobjective optimization (MOO) all direct-search methods of directional type. We prove under the common assumptions used in direct search for single objective optimization that at least one limit point of the sequence of iterates generated by DMS lies in (a stationary form of) the Pareto front. However, extensive computational experience has shown that our methodology has an impressive capability of generating the whole Pareto front, even without using a search step. Two by-products of this paper are (i) the development of a collection of test problems for MOO and (ii) the extension of performance and data profiles to MOO, allowing a comparison of several solvers on a large set of test problems, in terms of their efficiency and robustness to determine Pareto fronts.

Intelligent energy resources management in the context of smart grids

Smart grids are envisaged as infrastructures able to accommodate all centralized and distributed energy resources (DER), including intensive use of renewable and distributed generation (DG), storage, demand response (DR), and also electric vehicles (EV), from which plug-in vehicles, i.e. gridable vehicles, are especially relevant. Moreover, smart grids must accommodate a large number of diverse types or players in the context of a competitive business environment. Smart grids should also provide the required means to efficiently manage all these resources what is especially important in order to make the better possible use of renewable based power generation, namely to minimize wind curtailment. An integrated approach, considering all the available energy resources, including demand response and storage, is crucial to attain these goals. This paper proposes a methodology for energy resource management that considers several Virtual Power Players (VPPs) managing a network with high penetration of distributed generation, demand response, storage units and network reconfiguration. The resources are controlled through a flexible SCADA (Supervisory Control And Data Acquisition) system that can be accessed by the evolved entities (VPPs) under contracted use conditions. A case study evidences the advantages of the proposed methodology to support a Virtual Power Player (VPP) managing the energy resources that it can access in an incident situation.

Towards a future SCADA

Currently, Power Systems (PS) already accommodate a substantial penetration of DG and operate in competitive environments. In the future PS will have to deal with largescale integration of DG and other distributed energy resources (DER), such as storage means, and provide to market agents the means to ensure a flexible and secure operation. This cannot be done with the traditional PS operation. SCADA (Supervisory Control and Data Acquisition) is a vital infrastructure for PS. Current SCADA adaptation to accommodate the new needs of future PS does not allow to address all the requirements. In this paper we present a new conceptual design of an intelligent SCADA, with a more decentralized, flexible, and intelligent approach, adaptive to the context (context awareness). Once a situation is characterized, data and control options available to each entity are re-defined according to this context, taking into account operation normative and a priori established contracts. The paper includes a case-study of using future SCADA features to use DER to deal with incident situations, preventing blackouts.

Relatório de estágio: POC para SNC

Mestrado em Contabilidade

Energy resource management in smart grids considering an Intensive use of electric vehicles

The introduction of electricity markets and integration of Distributed Generation (DG) have been influencing the power system’s structure change. Recently, the smart grid concept has been introduced, to guarantee a more efficient operation of the power system using the advantages of this new paradigm. Basically, a smart grid is a structure that integrates different players, considering constant communication between them to improve power system operation and management. One of the players revealing a big importance in this context is the Virtual Power Player (VPP). In the transportation sector the Electric Vehicle (EV) is arising as an alternative to conventional vehicles propel by fossil fuels. The power system can benefit from this massive introduction of EVs, taking advantage on EVs’ ability to connect to the electric network to charge, and on the future expectation of EVs ability to discharge to the network using the Vehicle-to-Grid (V2G) capacity. This thesis proposes alternative strategies to control these two EV modes with the objective of enhancing the management of the power system. Moreover, power system must ensure the trips of EVs that will be connected to the electric network. The EV user specifies a certain amount of energy that will be necessary to charge, in order to ensure the distance to travel. The introduction of EVs in the power system turns the Energy Resource Management (ERM) under a smart grid environment, into a complex problem that can take several minutes or hours to reach the optimal solution. Adequate optimization techniques are required to accommodate this kind of complexity while solving the ERM problem in a reasonable execution time. This thesis presents a tool that solves the ERM considering the intensive use of EVs in the smart grid context. The objective is to obtain the minimum cost of ERM considering: the operation cost of DG, the cost of the energy acquired to external suppliers, the EV users payments and remuneration and penalty costs. This tool is directed to VPPs that manage specific network areas, where a high penetration level of EVs is expected to be connected in these areas. The ERM is solved using two methodologies: the adaptation of a deterministic technique proposed in a previous work, and the adaptation of the Simulated Annealing (SA) technique. With the purpose of improving the SA performance for this case, three heuristics are additionally proposed, taking advantage on the particularities and specificities of an ERM with these characteristics. A set of case studies are presented in this thesis, considering a 32 bus distribution network and up to 3000 EVs. The first case study solves the scheduling without considering EVs, to be used as a reference case for comparisons with the proposed approaches. The second case study evaluates the complexity of the ERM with the integration of EVs. The third case study evaluates the performance of scheduling with different control modes for EVs. These control modes, combined with the proposed SA approach and with the developed heuristics, aim at improving the quality of the ERM, while reducing drastically its execution time. The proposed control modes are: uncoordinated charging, smart charging and V2G capability. The fourth and final case study presents the ERM approach applied to consecutive days.

Análise e melhoria de processo de pintura e vulcanização na Continental

A indústria automóvel é um dos setores mais exigentes do mercado global, por este motivo empresas como a Continental Mabor S.A, líderes de mercado, necessitam estar na linha da frente no que toca a programas de melhoria contínua e de uma gestão orientada para um crescimento rentável e sustentado. Nesta perspetiva, este estudo de dissertação tem como objetivo encontrar uma solução para a gestão de stock e FiFo (First in First out) de pneus em verde na supracitada empresa, situada em Lousado, Vila Nova de Famalicão. Este projeto de dissertação iniciou-se com uma análise e diagnóstico do processo produtivo do pneu, entre a Construção e a Vulcanização. Nesta análise, foi possível identificar vários problemas, sendo o mais crítico associado à logística interna de transporte do pneu “em curso”, de fabrico entre as fases do mesmo, Construção e Vulcanização. Devido a condicionantes estruturais e de organização, a logística interna de transporte entre estes dois sectores enfrenta estrangulamentos nos fluxos, a falta de espaço para acomodar o material em curso, problemas organizacionais de controlo e monitorização do processo produtivo, dificuldades de regulação do fluxo e localização dos carros de transporte dos pneus em verde. Face aos problemas detetados ao longo do estudo, foram analisadas várias soluções para a resolução ou minimização dos mesmos. Entre as soluções propostas salientam-se: o alargamento do sistema de transporte por tapetes rolantes GTC (Green Tire Conveying) a todos os módulos de construção. Esta solução diminui o fluxo de carros para a área da construção, descongestionando a zona próxima do sistema de carregamento automático GTAL (Green Tire Automatic Loading) na vulcanização. A implementação dum sistema Wi-Fi RFID, que permite identificar e localizar artigos em curso utilizando etiquetas inteligentes numa rede wireless, conseguindo melhorar a programação de produção e o respetivo sequenciamento. Sabendo também que a Continental se encontra numa fase de expansão, designada Projeto Route 17/20, as soluções propostas tomaram em consideração essa nova realidade futura. Assim, foram estudados e propostos novos layouts para esse atual processo. Nestes novos layouts, procurou-se uma reorganização dos processos de fabrico, bem como um redimensionamento dos espaços de parqueamento de carros de pneus verdes adequado aos volumes produtivos. De igual forma, adequou-se os espaços físicos à possível implementação de um sistema de FiFo de pneus em verde na planta fabril, quando concluída a expansão. Este trabalho de dissertação apresenta como vantagens diretas da sua implementação: gerar a menor perturbação no atual método de trabalho seguido na empresa; previsivelmente aumentar a eficiência do processo produtivo; potenciar o crescimento tecnológico programado pela empresa; e oferecer uma boa relação custo/benefício no investimento necessário. Como apreciação final, pode-se concluir que este estudo foi finalizado com sucesso, visto que as soluções propostas foram apreciadas positivamente pela Administração da Continental Mabor S.A. e estão correntemente a ser avaliadas pelo grupo.

Controlador dedicado de Ecrãs LCD/TFT

Para dar resposta aos grandes avanços tecnológicos e, consequentemente, à postura mais exigente dos clientes, a empresa Francisco Parracho – Electrónica Industrial, Lda., que tem actividade no ramo dos elevadores, decidiu introduzir no mercado um controlador dedicado de ecrãs Liquid Crystal Display / Thin Film Transistor (LCD / TFT). O objectivo é substituir um sistema suportado por um computador, caracterizado pelas suas elevadas dimensões e custos, mas incontornável até à data, nomeadamente para resoluções de ecrã elevadas. E assim nasceu este trabalho. Com uma selecção criteriosa de todos os componentes e, principalmente, sem funcionalidades inúteis, obteve-se um sistema embebido com dimensões e custos bem mais reduzidos face ao seu opositor. O ecrã apontado para este projecto é um Thin Film Transistor – Liquid Crystal Display (TFT-LCD) da Sharp de 10.4” de qualidade industrial, com uma resolução de 800 x 600 píxeis a 18 bits por píxel. Para tal, foi escolhido um micro-controlador da ATMEL, um AVR de 32 bits que, entre outras características, possui um controlador LCD que suporta resoluções até 2048 x 2048 píxeis, de 1 a 24 bits por píxel. Atendendo ao facto deste produto ser inserido na área dos elevadores, as funcionalidades, quer a nível do hardware quer a nível do software, foram projectadas para este âmbito. Contudo, o conceito aqui exposto é adjacente a quaisquer outras áreas onde este produto se possa aplicar, até porque o software está feito para se tornar bem flexível. Com a ajuda de um kit de desenvolvimento, foram validados os drivers dos controladores e periféricos base deste projecto. De seguida, aplicou-se esse software numa placa de circuito impresso, elaborada no âmbito deste trabalho, para que fossem cumpridos todos os requisitos requeridos pela empresa patrocinadora: - Apresentação de imagens no ecrã consoante o piso; - Possibilidade de ter um texto horizontalmente deslizante;Indicação animada do sentido do elevador; - Representação do piso com deslizamento vertical; - Descrição sumária do directório de pisos também com deslizamento vertical; - Relógio digital; - Leitura dos conteúdos pretendidos através de um cartão SD/MMC; - Possibilidade de actualização dos conteúdos via USB flash drive.

Biochemistry of adipose tissue: an endocrine organ

Adipose tissue is no longer considered to be an inert tissue that stores fat. This tissue is capable of expanding to accommodate increased lipids through hypertrophy of existing adipocytes and by initiating differentiation of pre-adipocytes. Adipose tissue metabolism exerts an impact on whole-body metabolism. As an endocrine organ, adipose tissue is responsible for the synthesis and secretion of several hormones. These are active in a range of processes, such as control of nutritional intake (leptin, angiotensin), control of sensitivity to insulin and inflammatory process mediators (tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), resistin, visfatin, adiponectin, among others) and pathways (plasminogen activator inhibitor 1 (PAI-1) and acylation stimulating protein (ASP) for example). This paper reviews some of the biochemical and metabolic aspects of adipose tissue and its relationship to inflammatory disease and insulin resistance.

SPARTS: simulator for power aware and real-time systems

Real-time systems demand guaranteed and predictable run-time behaviour in order to ensure that no task has missed its deadline. Over the years we are witnessing an ever increasing demand for functionality enhancements in the embedded real-time systems. Along with the functionalities, the design itself grows more complex. Posed constraints, such as energy consumption, time, and space bounds, also require attention and proper handling. Additionally, efficient scheduling algorithms, as proven through analyses and simulations, often impose requirements that have significant run-time cost, specially in the context of multi-core systems. In order to further investigate the behaviour of such systems to quantify and compare these overheads involved, we have developed the SPARTS, a simulator of a generic embedded real- time device. The tasks in the simulator are described by externally visible parameters (e.g. minimum inter-arrival, sporadicity, WCET, BCET, etc.), rather than the code of the tasks. While our current implementation is primarily focused on our immediate needs in the area of power-aware scheduling, it is designed to be extensible to accommodate different task properties, scheduling algorithms and/or hardware models for the application in wide variety of simulations. The source code of the SPARTS is available for download at [1].

Comparing the schedulers and power saving strategies with SPARTS

We have developed SPARTS, a simulator of a generic embedded real-time device. It is designed to be extensible to accommodate different task properties, scheduling algorithms and/or hardware models for the wide variety of applications. SPARTS was developed to help the community investigate the behaviour of the real-time embedded systems and to quantify the associated constraints/overheads.

POSIX trace based behavioural reflection

Traditional Real-Time Operating Systems (RTOS) are not designed to accommodate application specific requirements. They address a general case and the application must co-exist with any limitations imposed by such design. For modern real-time applications this limits the quality of services offered to the end-user. Research in this field has shown that it is possible to develop dynamic systems where adaptation is the key for success. However, adaptation requires full knowledge of the system state. To overcome this we propose a framework to gather data, and interact with the operating system, extending the traditional POSIX trace model with a partial reflective model. Such combination still preserves the trace mechanism semantics while creating a powerful platform to develop new dynamic systems, with little impact in the system and avoiding complex changes in the kernel source code.

TRAILER project overview: tagging, recognition and acknowledgment of informal learning experiences

The evolution of new technology and its increasing use, have for some years been making the existence of informal learning more and more transparent, especially among young and older adults in both Higher Education and workplace contexts. However, the nature of formal and non-formal, course-based, approaches to learning has made it hard to accommodate these informal processes satisfactorily, and although technology bring us near to the solution, it has not yet achieved. TRAILER project aims to address this problem by developing a tool for the management of competences and skills acquired through informal learning experiences, both from the perspective of the user and the institution or company. This paper describes the research and development main lines of this project.

Coalition based approach for shop floor agility – a multiagent approach

Dissertation submitted for a PhD degree in Electrical Engineering, speciality of Robotics and Integrated Manufacturing from the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Remote and mobile experimentation: pushing the boundaries of an ubiquitous learning place

Concepts like E-learning and M-learning are changing the traditional learning place. No longer restricted to well-defined physical places, education on Automation and other Engineering areas is entering the so-called ubiquitous learning place, where even the more practical knowledge (acquired at lab classes) is now moving into, due to emergent concepts such as Remote Experimentation or Mobile Experimentation. While Remote Experimentation is traditionally regarded as the remote access to real-world experiments through a simple web browser running on a PC connected to the Internet, Mobile Experimentation may be seen as the access to those same (or others) experiments, through mobile devices, used in M-learning contexts. These two distinct client types (PCs versus mobile devices) pose specific requirements for the remote lab infrastructure, namely the ability to tune the experiment interface according to the characteristics (e.g. display size) of the accessing device. This paper addresses those requirements, namely by proposing a new architecture for the remote lab infrastructure able to accommodate both Remote and Mobile Experimentation scenarios.

Dioszegia antarctica sp. nov. and Dioszegia cryoxerica sp. nov., psychrophilic basidiomycetous yeasts from polar desert soils in Antarctica

International Journal of Systematic and Evolutionary Microbiology, 60