Optimization model for medium term natural gas commitment

In this paper we study the optimal natural gas commitment for a known demand scenario. This study implies the best location of GSUs to supply all demands and the optimal allocation from sources to gas loads, through an appropriate transportation mode, in order to minimize total system costs. Our emphasis is on the formulation and use of a suitable optimization model, reflecting real-world operations and the constraints of natural gas systems. The mathematical model is based on a Lagrangean heuristic, using the Lagrangean relaxation, an efficient approach to solve the problem. Computational results are presented for Iberian and American natural gas systems, geographically organized in 65 and 88 load nodes, respectively. The location model results, supported by the computational application GasView, show the optimal location and allocation solution, system total costs and suggest a suitable gas transportation mode, presented in both numerical and graphic supports.

Liderança virtuosa, comprometimento organizacional e desempenho individual

Num mundo hipercompetitivo, a afirmação da virtuosidade tem enfrentado consideráveis resistências, sendo mesmo considerada como sinónimo de fraqueza ou ingenuidade. Todavia, e perante evidências dos potenciais perigos do exercício da liderança desprovido de valores, ética e moralidade, elevam-se as vozes em defesa de uma liderança virtuosa, capaz de aportar contributos significativamente positivos às organizações e seus colaboradores. Partindo desta premissa, esta investigação teve como objetivo analisar, com base nas perceções dos liderados, o impacto da liderança virtuosa no comprometimento organizacional, assim como o contributo deste último no desempenho individual. Sustentados numa metodologia quantitativa, inquirimos, numa primeira fase, 113 liderados provenientes de organizações localizadas no território português, com vista a apurar quais as virtudes que mais valorizavam num líder. Os dados para o teste de hipóteses foram recolhidos através da aplicação de uma bateria de testes junto de 351 liderados, também a exercer funções em organizações a operar em Portugal. Os resultados sugerem que as perceções dos liderados em torno de três dimensões de virtuosidade da liderança (liderança baseada em valores, perseverança e maturidade) contribuem para o comprometimento organizacional, sobretudo nas suas vertentes afetiva e normativa e, que este último, por sua vez, é capaz de influenciar positivamente o desempenho individual.

A new MILP based approach for unit commitment in power production planning

This paper presents a complete, quadratic programming formulation of the standard thermal unit commitment problem in power generation planning, together with a novel iterative optimisation algorithm for its solution. The algorithm, based on a mixed-integer formulation of the problem, considers piecewise linear approximations of the quadratic fuel cost function that are dynamically updated in an iterative way, converging to the optimum; this avoids the requirement of resorting to quadratic programming, making the solution process much quicker. From extensive computational tests on a broad set of benchmark instances of this problem, the algorithm was found to be flexible and capable of easily incorporating different problem constraints. Indeed, it is able to tackle ramp constraints, which although very important in practice were rarely considered in previous publications. Most importantly, optimal solutions were obtained for several well-known benchmark instances, including instances of practical relevance, that are not yet known to have been solved to optimality. Computational experiments and their results showed that the method proposed is both simple and extremely effective.

Linking transformational leadership and organisation commitment

The main goal of this paper is to analyse the impacts of transformational leadership on organisational commitment. To this effect we developed a case study following a quantitative methodological approach. The research was conducted at the Serralves Foundation (Porto, Portugal) to empirically test the proposed research model and its hypothesis. The empirical results confirm that transformational leadership are not significantly influenced by commitment. As the main limitation of this study we highlight the fact that it does not consider the leaders’ perspective on their subordinates’ behaviour.

A Multiple Criteria Utility-based Approa h for the Unit Commitment with Wind Power and Pumped Storage Hydro

The integration of wind power in eletricity generation brings new challenges to unit commitment due to the random nature of wind speed. For this particular optimisation problem, wind uncertainty has been handled in practice by means of conservative stochastic scenario-based optimisation models, or through additional operating reserve settings. However, generation companies may have different attitudes towards operating costs, load curtailment, or waste of wind energy, when considering the risk caused by wind power variability. Therefore, alternative and possibly more adequate approaches should be explored. This work is divided in two main parts. Firstly we survey the main formulations presented in the literature for the integration of wind power in the unit commitment problem (UCP) and present an alternative model for the wind-thermal unit commitment. We make use of the utility theory concepts to develop a multi-criteria stochastic model. The objectives considered are the minimisation of costs, load curtailment and waste of wind energy. Those are represented by individual utility functions and aggregated in a single additive utility function. This last function is adequately linearised leading to a mixed-integer linear program (MILP) model that can be tackled by general-purpose solvers in order to find the most preferred solution. In the second part we discuss the integration of pumped-storage hydro (PSH) units in the UCP with large wind penetration. Those units can provide extra flexibility by using wind energy to pump and store water in the form of potential energy that can be generated after during peak load periods. PSH units are added to the first model, yielding a MILP model with wind-hydro-thermal coordination. Results showed that the proposed methodology is able to reflect the risk profiles of decision makers for both models. By including PSH units, the results are significantly improved.

Supporting leadership development by exposure to role models: two case studies

The idiomatic expression “In Rome be a Roman” can be applied to leadership training and development as well. Leaders who can act as role models inspire other future leaders in their behaviour, attitudes and ways of thinking. Based on two examples of current leaders in the fields of Politics and Public Administration, I support the idea that exposure to role models during their training was decisive for their career paths and current activities as prominent characters in their profession. Issues such as how students should be prepared for community or national leadership as well as cross-cultural engagement are raised here. The hypothesis of transculturalism and cross-cultural commitment as a factor of leadership is presented. Based on current literature on Leadership as well as the presented case studies, I expect to raise a debate focusing on strategies for improving leaders’ training in their cross-cultural awareness.

O Contributo do sistema SAP R/3 no controlo interno na REFER

Dissertação apresentada ao Instituto Superior de Contabilidade para a obtenção do Grau de Mestre em Auditoria Orientador: Mestre Agostinho Sousa Pinto

The influence of relationship quality and culture in the relations between exporter and distributor : the case of portuguese exports to Angola

The objective of this research is to investigate the role of the relationship quality, cooperation and culture between Portuguese companies and their export market intermediaries in Angola. In particular, we aim to understand the importance that the quality of the relationship has in cooperation and the role of cultures in export activities. An important aspect of this study is precisely the fact that it includes an African country, where, in terms of the literature, there is a strong lack of studies. In terms of methodology we opted for qualitative analysis; we present the results of two case studies of Portuguese exporting companies and one case study of Angolan intermediate. In general, the results are that the business relationships are characterized by trust, commitment, cooperation, culture, similar values, as in the past, Angola belonged to Portugal there is easy communication because both countries share the same. Such factors will influence the trade relations between Portuguese exporters and their Angolan distributors.

Optimal dispatch with reactive power compensation by Genetic Algorithm

This paper presents a Unit Commitment model with reactive power compensation that has been solved by Genetic Algorithm (GA) optimization techniques. The GA has been developed a computational tools programmed/coded in MATLAB. The main objective is to find the best generations scheduling whose active power losses are minimal and the reactive power to be compensated, subjected to the power system technical constraints. Those are: full AC power flow equations, active and reactive power generation constraints. All constraints that have been represented in the objective function are weighted with a penalty factors. The IEEE 14-bus system has been used as test case to demonstrate the effectiveness of the proposed algorithm. Results and conclusions are dully drawn.

Personality, emotion, and mood in agent-based group decision making

Group decision making plays an important role in organizations, especially in the present-day economy that demands high-quality, yet quick decisions. Group decision-support systems (GDSSs) are interactive computer-based environments that support concerted, coordinated team efforts toward the completion of joint tasks. The need for collaborative work in organizations has led to the development of a set of general collaborative computer-supported technologies and specific GDSSs that support distributed groups (in time and space) in various domains. However, each person is unique and has different reactions to various arguments. Many times a disagreement arises because of the way we began arguing, not because of the content itself. Nevertheless, emotion, mood, and personality factors have not yet been addressed in GDSSs, despite how strongly they influence results. Our group’s previous work considered the roles that emotion and mood play in decision making. In this article, we reformulate these factors and include personality as well. Thus, this work incorporates personality, emotion, and mood in the negotiation process of an argumentbased group decision-making process. Our main goal in this work is to improve the negotiation process through argumentation using the affective characteristics of the involved participants. Each participant agent represents a group decision member. This representation lets us simulate people with different personalities. The discussion process between group members (agents) is made through the exchange of persuasive arguments. Although our multiagent architecture model4 includes two types of agents—the facilitator and the participant— this article focuses on the emotional, personality, and argumentation components of the participant agent.

Diagnóstico ambiental dos estabelecimentos de ensino orientado para a implementação de um sistema de gestão ambiental

As instituições de ensino procuram ser impulsionadoras de boas práticas ambientais demonstrando com isso o seu compromisso com o meio ambiente e com as gerações futuras. Os Sistemas de Gestão Ambiental (SGA), nomeadamente as exigências da ISO 14001:2004 podem ser uma oportunidade para as instituições gerirem correctamente todos os seus recursos, assim como eliminarem os riscos e custos desnecessários, ao mesmo tempo que reforçam os seus valores quanto à protecção do meio ambiente, prevenção da poluição, cumprimento legal e as necessidades socioeconómicas. Pretendeu-se com este estudo determinar quais os factores que condicionam a abordagem de uma política ambiental nos estabelecimentos de ensino, relacionando-as com as diferentes características das escolas com as suas abordagens ambientais, assim como determinar quais os factores que influenciam a postura ambiental das escolas. Os resultados foram recolhidos através de um inquérito por questionário, direccionado para os estabelecimentos de ensino pré-escolar, 1º, 2º, 3º ciclos e secundário da Área Metropolitana do Porto. Através da análise das respostas de 405 escolas, conclui-se que aqueles com melhores desempenhos ambientais e melhores condições para implementar um SGA são os estabelecimentos de ensino com a tipologia EB2,3/ES, públicos, pertencentes aos concelhos de Gondomar, Mais e Sto Tirso, localizados nas zonas urbanas e com edifícios escolares recentes em excelentes ou bons estados de conservação. De um modo geral todos os estabelecimentos de ensino demonstram um desempenho ambiental considerado bom e acima do considerado satisfatório para a implementação de um SGA.

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Mestrado em Engenharia Informática