ISE - Comunicações em actas de encontros científicos internacionais
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- Short-Term scheduling of a polymer compounding plantPublication . Castro, Pedro; Barbosa-Póvoa, Ana Paula; Matos, Henrique A.This paper addresses the optimal short-term scheduling of a three parallel production line plymer compounding plant, whose equipments require cleaning between product changeovers. A very effective user-friendly software tool was developed, which consists of a general scheduling model coupled with capabilities of Microsoft Excel for data handling and analysis. The scheduling model is based on a Resource Task Network discrete time formulation and leads to Mixed Integer Linear Programming problems. As outputs the user can access the optimal schedules for a number of different objectives.
- Analysis of processing systems involving reaction and distillation : the synthesis of ethyl acetatePublication . Filipe, Rui M.; Castro, Pedro; Matos, Henrique A.; Novais, Augusto Q.The integration of reaction and separation into a single process unit, i. e., reactive destillation, may offer several advantages over conventional systems that use a reactor followed by a distillation column. In this paper we explore the operational characteristics of reactive distillation and highlight some of this potential benefits, using the production of ethyl acetate as an illustrative example. With this aim, the two types of system are compared employing different reactor types and a number of performance indicators, such as yield, conversion, purity, specific energy consumption and residence time. A sensitivity analysis is carried out on some variables and parameters, in order to explore and define the distillation columns operating conditions. As expected, results point to a clear advantage of reactive distillation allowing for the azeotrope to be surpassed and for the overcoming of chemical equilibrium, favouring an increase in conversion and product purity, along with reduced operating costs.
- LP-based heuristic procedure for the optimal design of water using networks with multi-contaminantsPublication . Teles, João P.; Castro, Pedro; Barbosa-Póvoa, Ana Paula; Novais, Augusto Q.This paper proposes a new strategy for the optimal design of water-using networks in industrial systems featuring possibly more than a single water source and multiple contaminants. The model formulation is supported on a superstructure that exploits reuse opportunities and gives rise to a non-convex nonlinear which often leads to local optimal solutions. To overcome this, the new approach generates multiple initialization points, one for each possible sequence of operations, where a particular starting point is obtained by the sequential solution of a small set of related linear programs. The best solution of the several non-linear problems that are solved is then assumed to be the global optimal solution. The results obtained for a set of case studies have shown that the best initialization point is often the global optimal solution and that the procedure as a whole is efficient in escaping local optima.
- Return mobility of scientists and knowledge circulation : an exploratory approach to scientists attitudes and perspectivesPublication . Fontes, MargaridaThe paper addresses the international mobility and return of scientists and its implications for regions/countries with weaker scientific and technological systems. It focuses on the “return dilemma” and, using the Portuguese case as empirical setting, discusses the conditions for return, the “diaspora” alternative and the role of policies in minimising the impacts of mobility flows. Despite the growing importance assumed by scientific mobility, our understanding of mobility flows, in particular of return mobility, is still deficient. Data about the level of mobility and mobility paths is scarce and difficult to obtain and the knowledge about expatriate scientists’ motivations and strategies, namely their attitudes towards the home country and their perspectives concerning career and return mobility, remains limited. The research presented in this paper is a preliminary contribution to attend to some of these issues. A method is proposed to address some methodological problems in empirical research on scientific mobility. It permits to delimit a sample of “scientifically productive” expatriate scientists in specific fields, to locate these scientists and to trace their professional trajectories, thus making possible to collect information on their mobility behaviour as well as to gain some preliminary insights on their attitudes and perspectives. This methodology is experimentally applied to the Portuguese case. Notwithstanding its exploratory nature, the empirical research provides some insights into the behaviour of a younger generation of “scientifically productive scientists” in a field with a strong international mobility pattern (biotechnology), which can be relevant for policy making
- Towards an interdisciplinary framework for automated negotiationPublication . Lopes, Fernando; Novais, Augusto Q.; Coelho, HelderNegotiation is an important and pervasive form of social interaction. The design of autonomous negotiating agents involves the consideration of insights from multiple relevant research areas to integrate different perspectives on negotiation. As a starting point for an interdisciplinary research effort, this paper presents a model that handles bilateral multi-issue negotiation, employs game-theoretic techniques to define equilibrium strategies for the bargaining game of alternating offers, and formalizes a set of negotiation strategies and tactics studied in the social sciences. Autonomous agents equipped with the model are currently being developed using the Jade framework. The agents are able to negotiate under both complete and incomplete information, thereby making the model in particular and the agents in general very compelling for automated negotiation
- Performance indicators for reactive distillation designPublication . Filipe, Rui M.; Matos, Henrique A.; Novais, Augusto Q.A cost indicator for the design and multi-objective optimization of reactive distillation columns, designated capacity, was introduced in previous work by the authors. The question of this indicator’s effectiveness as a measure of the actual column cost, is herein investigated over a number of designs by comparing it with the value obtained by means of conventional costing procedures. The results show that the level of accuracy obtained when using capacity is satisfactory and certainly acceptable for a preliminary design stage.
- The evolution of negotiation and impasse in two-party multi-issue bargainingPublication . Lopes, Fernando; Novais, Augusto Q.; Coelho, HelderAutomated negotiation systems are becoming increasingly important and pervasive. Most previous research on automated negotiation has focused on understanding and formalizing “successful” negotiations, i.e., negotiations that do not become contentious to the point of impasse. This paper shifts the emphasis to negotiations that are “difficult” to resolve and can hit an impasse. It analyses a situation where two agents bargain over the division of the surplus of several distinct issues to demonstrate how a procedure to avoid impasses can be utilized in a specific negotiation setting. The procedure is based on the addition of new issues to the agenda during the course of negotiation and the exploration of the differences in the valuation of these issues to capitalize on Pareto optimal agreements. This paper also lays the foundation for performing an experiment to investigate how the evolution of negotiation contributes to the avoidance of impasses, paying particular attention to the expansion of the number of issues to be deliberated and its impact on the frequency of impasses
- Simulation of immune system response to bacterial challengePublication . Fachada, Nuno; Lopes, Vitor V.; Rosa, AgostinhoImmune system (IS) simulations have several applications, such as biological theory testing or as a complement in the development of improved drugs. This paper presents an agent based approach to simulate the IS response to bacterial infection challenge. The agent simulator is implemented in a discrete time and twodimensional space, and composed by two layers: a) a specialized cellular automata responsible for substance di usion and reactions; and b) the layer where agents move, act and interact. The IS model focuses upon low level cellular receptor interactions, receptor diversity and genetic-ruled agents, aiming to observe and study the resultant emergent behavior. The model reproduces the following IS behavioral characteristics: speci city and specialization, immune memory and vaccine immunization.
- The role of entrepreneurs social networks in the creation and early development of biotechnology companiesPublication . Sousa, Cristina; Videira, Pedro; Fontes, MargaridaThe main research question addressed in this paper concerns the way entrepreneurs’ social networks affect the opportunity identification and the access and mobilization of resources in a science-based field – biotechnology - facilitating the founding of new firms. For this purpose we adopted an analytical framework combining contributions from the technological entrepreneurship and the social network literature and, on this basis, we proposed: i) that entrepreneurs social networks, both those associated with their academic and professional trajectories and those intentionally build already having the firm as a goal, are critical to access the wide range of resources necessary to create a new firm in this type of field; ii) that different network configurations are associated with the access and mobilisation of different types of resources. We developed a methodology that combines several methods usually applied separately and that permits to assemble of a vast array of data capturing the nature and contents of a wide range of relationships. This methodology was applied to a sub-set of the Portuguese biotechnology industry – the molecular biology firms. Globally this research provides evidence that contributes to on-going debates in the area of social networks and entrepreneurship, both at the methodological and empirical levels. At this stage the main contribution regards the development of a methodology that was found to offer important insights into the behaviour of science-based entrepreneurs in their search for key resources for firm formation. The results obtained, although still exploratory, already provide some indications concerning the conditions for biotechnology entrepreneurship in countries that are peripheral relative to the major concentrations of biotechnology knowledge and business.
- Yeast metabolic state identification by fiber optics spectroscopyPublication . Castro, C. C.; Silva, J. S.; Lopes, Vitor V.; Martins, R. C.In this manuscript we explore the feasibility of using LWUV-VIS-SWNIR (340 - 1100 nm) spectroscopy to classify Saccharomyces cerevisiae colony structures in YP agar and YPD agar, under different growth conditions, such as: i) no alcohol; ii) 1 % (v/v) Ethanol; iii) 1 % (v/v) 1-Propanol; iv) 1 % (v/v) 1- butanol; v) 1 % (v/v) Isopropanol; vi) 1 % (v/v) (±)-1-Phenylethanol; vii) 1 % (v/v) Isoamyl alcohol; viii) 1 % (v/v) tert-Amyl alcohol (2-Methyl-2-butanol); and ix) 1 % (v/v) Amyl alcohol. Results show that LWUV-VISSWNIR spectroscopy has the potential for yeasts metabolic state identification once the spectral signatures of colonies differs from each others, being possible to acheive 100% of classification in UV-VIS and VISSWNIR. The UV-VIS region present high discriminant information (350-450 nm), and different responses to UV excitation were obtained. Therefore, high precision is obtained because UV-VIS and VIS-NIR exhibit different kinds of information. In the future, high precision analytical chemistry techniques such as mass spectroscopy and molecular biology transcriptomic studies should be performed in order to understand the detailed cell metabolism and genomic phenomena that characterize the yeast colony state