25 resultados para NELSON, LEONARD
em Instituto Politécnico do Porto, Portugal
Resumo:
This paper presents a negotiation mechanism for Dynamic Scheduling based on Swarm Intelligence (SI). Under the new negotiation mechanism, agents must compete to obtain a global schedule. SI is the general term for several computational techniques which use ideas and get inspiration from the social behaviors of insects and other animals. This work is concerned with negotiation, the process through which multiple selfinterested agents can reach agreement over the exchange of operations on competitive resources.
Resumo:
Agility refers to the manufacturing system ability to rapidly adapt to market and environmental changes in efficient and cost-effective ways. This paper addresses the development of self-organization methods to enhance the operations of a scheduling system, by integrating scheduling system, configuration and optimization into a single autonomic process requiring minimal manual intervention to increase productivity and effectiveness while minimizing complexity for users. We intend to conceptualize real manufacturing systems as interacting autonomous entities in order to build future Decision Support Systems (DSS) for Scheduling in agile manufacturing environments.
Resumo:
Swarm Intelligence generally refers to a problem-solving ability that emerges from the interaction of simple information-processing units. The concept of Swarm suggests multiplicity, distribution, stochasticity, randomness, and messiness. The concept of Intelligence suggests that problem-solving approach is successful considering learning, creativity, cognition capabilities. This paper introduces some of the theoretical foundations, the biological motivation and fundamental aspects of swarm intelligence based optimization techniques such Particle Swarm Optimization (PSO), Ant Colony Optimization (ACO) and Artificial Bees Colony (ABC) algorithms for scheduling optimization.
Resumo:
Swarm Intelligence (SI) is a growing research field of Artificial Intelligence (AI). SI is the general term for several computational techniques which use ideas and get inspiration from the social behaviours of insects and of other animals. This paper presents hybridization and combination of different AI approaches, like Bio-Inspired Techniques (BIT), Multi-Agent systems (MAS) and Machine Learning Techniques (ML T). The resulting system is applied to the problem of jobs scheduling to machines on dynamic manufacturing environments.
Resumo:
Este artigo propõe um Mecanismo de Negociação para Escalonamento Dinâmico com recurso a Swarm Intelligence (SI). No Mecanismo de Negociação, os agentes devem competir para obter um plano de escalamento global. SI é o termo geral para várias técnicas computacionais que retiram ideias e inspiração nos comportamentos sociais de insectos e outros animais. Este artigo propõe uma abordagem híbrida de diferentes conceitos da Inteligência Artificial (IA), como SI, Negociação em Sistemas Multi-Agente (SMA) e Técnicas de Aprendizagem Automática (AA). Este trabalho concentra a sua atenção na negociação, processo através do qual múltiplos agentes auto-interessados podem chegar a acordo através da troca competitiva de recursos.
Resumo:
We describe a novel approach to scheduling resolution by combining Autonomic Computing (AC), Multi-Agent Systems (MAS) and Nature Inspired Optimization Techniques (NIT). Autonomic Computing has emerged as paradigm aiming at embedding applications with a management structure similar to a central nervous system. A natural Autonomic Computing evolution in relation to Current Computing is to provide systems with Self-Managing ability with a minimum human interference. In this paper we envisage the use of Multi-Agent Systems paradigm for supporting dynamic and distributed scheduling in Manufacturing Systems with Autonomic properties, in order to reduce the complexity of managing systems and human interference. Additionally, we consider the resolution of realistic problems. The scheduling of a Cutting and Treatment Stainless Steel Sheet Line will be evaluated. Results show that proposed approach has advantages when compared with other scheduling systems.
Resumo:
The present paper results of an ongoing research project were it is expected to develop an information system to monitoring a cultural-touristic route. The route to monitor is the Romanesque Route of Tâmega. This Route is composed of 58 monuments located in the region of Tâmega in the North of Portugal. Due to the particular location of this region, that is between coastal zone, but not yet in the inland, it has a weak political influence, and it is reflected in the low levels of development at several levels, observed. The Romanesque Route was implemented in a part of this region in 1998, and enlarged to the all-region in 2010. In order to evaluate the socio-ecomonic impact of this route in the region a research project is being developed. The main goal of this paper is to open a discussion on the elements that must be taken into consideration to evaluate the economic and social impact of a touristic cultural route within a region and this one in particular.
Resumo:
In the present paper we will consider strategies of innovation, risk and proactivity as entre/ intrapreneurship strategies. This study was done in a Portuguese and in a Polish region. In Portugal the region was Vale do Sousa, located in the northern Portugal. The Polish region was Lublin Voivodeship and it is situated in the south-eastern part of the country. The study focused on Industrial and Construction sectors. In order to get a valid sample, a group of 251 firms were analysed in Portugal, and 215 in Poland. However, the minimum sample size in Poland should be 323. Since this is a work in progress, we are aiming for this number of questionnaires. Each strategy was analysed individually for both regions and the results pointed to a lack of culture of entrepreneurship in firms’ management. Only Proactivity presented a positive result in firms’ management. Polish firms tend to be more innovative and more risk takers, while in proactivity Portuguese ones present a slightly higher result. Combining the strategy results, it was possible to identify that 61.2% of Portuguese firms present a low level of entrepreneurship, while 60% of Polish firms present a moderate level. Considering intrapreneurship good levels, while Portugal account for 5.2% this figure is 19.1% in Poland.
Resumo:
Small firms are a major player in development. Thus, entrepreneurship is frequently attached to these rms and it must be present in daily management of factors such as planning and cooperation. We intend to analyze these factors, comparing familiar and non-familiar businesses. This study was conducted in a Portuguese region in the north of Portugal - Vale do Sousa . The results allow us to conclude that even with some managerial di erences it was not possible to identify distinct patterns between them. The main goal of this paper is to open research lines on important issues to distinguish familiar from non-familiar businesses.
Resumo:
In the present paper we analyzed the behavior of firms in the construction and manufacturing sectors, located in the region of Vale do Sousa, in the north of Portugal. From the literature, even existing some disagreements, it is possible to conclude that planning is crucial for firms survival and growth. Cooperation is another aspect that the literature presents as an important factor for firms sustainability. It also plays a major role in competition, since firms are adopting coopetition strategies. By studying a sample of 251 firms, it was possible to realize, that the majority started their business without a formal planning, and they keep going without using it. In cooperation aspects, there is a lack of cooperation. It was possible to verify, that existing cooperation has some evidence but at a vertical level. These vertical relations were also identified in stakeholder’s involvement.
Resumo:
The goal of the present paper is to analyse the classic entrepreneurship strategies (Innovation, Risk and Proactivity) in small and medium-sized businesses. However as presented in the title, the study will go further by comparing the results of those strategies in familiar and nonfamiliar businesses. This study was carried on in construction and industry sectors, in the region of Vale do Sousa, in the north of Portugal. In order to classify businesses as familiar or non-familiar types two criterion were adopted: (1) Management Control, (2) Family Employability. On the opposite to some studies that present a larger percentage of familiar businesses in national and European entrepreneurial fabric, the criterion used leaded to a larger number of non-familiar businesses (53%). The results showed that in general SMEs in this region are not following entrepreneurship strategies. Analysing the entire sample without a separation of businesses by nature (familiar/non-familiar) only proactivity showed to be more present in the managerial decisions. There is a lack of innovation and risk culture. Comparing the groups only on proactivity tests was possible to verify some differences. It was concluded that non-familiar businesses are more proactive than familiar ones. Between those groups there are no statistical differences on the means of the variables innovation and risk. At the same time some tests were conducted to test the differences on the variable entrepreneurship. The results were similar to innovation and risk strategies: There are no significant differences on entrepreneurship between these groups of businesses.
Resumo:
In the present paper, entrepreneurship strategies and its relations with managers and management are analysed in order to evaluate who are the real entrepreneurs. This study was done in a region of northern Portugal (Vale do Sousa) and focus on Industrial and Construction sectors. The region is composed of six concelhos in some of which it is possible to identify some industrial districts. In order to get a valid sample, a group of 251 firms were analysed. The results present a high level of risk aversion and some findings that go with literature on innovation, such as higher levels of education lead to more innovative managers, or young managers are more innovative. It was concluded, that those managers that were able to search and explore opportunities in the past, present better levels of entrepreneurship in their firms.
Resumo:
This research work has been focused in the study of gallinaceous feathers, a waste that may be valorised as sorbent, to remove the Dark Blue Astrazon 2RN (DBA) from Dystar. This study was focused on the following aspects: optimization of experimental conditions through factorial design methodology, kinetic studies into a continuous stirred tank adsorber (at pH 7 and 20ºC), equilibrium isotherms (at pH 5, 7 and 9 at 20 and 45ºC) and column studies (at 20ºC, at pH 5, 7 and 9). In order to evaluate the influence of the presence of other components in the sorption of the dyestuff, all experiments were performed both for the dyestuff in aqueous solution and in real textile effluent. The pseudo-first and pseudo-second order kinetic models were fitted to the experimental data, being the latter the best fit for the aqueous solution of dyestuff. For the real effluent both models fit the experimental results and there is no statistical difference between them. The Central Composite Design (CCD) was used to evaluate the effects of temperature (15 - 45ºC) and pH (5 - 9) over the sorption in aqueous solution. The influence of pH was more significant than temperature. The optimal conditions selected were 45ºC and pH 9. Both Langmuir and Freundlich models could fit the equilibrium data. In the concentration range studied, the highest sorbent capacity was obtained for the optimal conditions in aqueous solution, which corresponds to a maximum capacity of 47± 4 mg g-1. The Yoon-Nelson, Thomas and Yan’s models fitted well the column experimental data. The highest breakthrough time for 50% removal, 170 min, was obtained at pH 9 in aqueous solution. The presence of the dyeing agents in the real wastewater decreased the sorption of the dyestuff mostly for pH 9, which is the optimal pH. The effect of pH is less pronounced in the real effluent than in aqueous solution. This work shows that feathers can be used as sorbent in the treatment of textile wastewaters containing DBA.
Resumo:
Purpose: To describe and compare the content of instruments that assess environmental factors using the International Classification of Functioning, Disability and Health (ICF). Methods: A systematic search of PubMed, CINAHL and PEDro databases was conducted using a pre-determined search strategy. The identified instruments were screened independently by two investigators, and meaningful concepts were linked to the most precise ICF category according to published linking rules. Results: Six instruments were included, containing 526 meaningful concepts. Instruments had between 20% and 98% of items linked to categories in Chapter 1. The highest percentage of items from one instrument linked to categories in Chapters 2–5 varied between 9% and 50%. The presence or absence of environmental factors in a specific context is assessed in 3 instruments, while the other 3 assess the intensity of the impact of environmental factors. Discussion: Instruments differ in their content, type of assessment, and have several items linked to the same ICF category. Most instruments primarily assess products and technology (Chapter 1), highlighting the need to deepen the discussion on the theory that supports the measurement of environmental factors. This discussion should be thorough and lead to the development of methodologies and new tools that capture the underlying concepts of the ICF.
Resumo:
O biodiesel é uma fonte de energia renovável, que se pode obter pela transformação dos resíduos domésticos, e é ambientalmente inócuo, e fácil de transportar, pois tem um ponto de fulgor elevado. Atualmente tem-se focado a atenção nos efeitos da oxidação do biodiesel causados pelo contato com o ar ambiente durante o seu armazenamento. Os produtores, fornecedores e consumidores, pretendem garantir que a qualidade do biodiesel e das suas misturas com combustíveis destilados do petróleo, mantém-se durante longos períodos de armazenamento. A maioria dos óleos vegetais e das gorduras animais, usados como matéria – prima, são triacilgliceróis com grupos ácido gordos de cadeia longa (C16 – C18) ligados por ligações éster a uma estrutura de glicerol. O objetivo deste estudo foi avaliar a eficiência do ácido gálhico e seus derivados alquilo ésteres aumentando a resistência relativa à oxidação do ácido linoléico, inibindo a peroxidação ácido gordos de cadeia longa insaturados. Outro objetivo foi estudar a taxa de inibição da auto-oxidação do ácido linoleico. Foi, ainda estudado o efeito que a concentração do antioxidante, tinha na estabilidade do ácido linoleico. No caso do ácido gálhico verificou-se que o aumento para o dobro da concentração do antioxidante utilizada, obtinha-se quase o dobro da taxa de inibição da oxidação do ácido linoleico. A auto-oxidação de ácido linoleico é acompanhada pela formação do seu dieno conjugado, o qual foi medido sua absorvância, durante 7 dias, por espetrofotometria de absorção UV a 234 nm. Uma diminuição da taxa de formação de dieno conjugado, indica o aumento da atividade antioxidante do composto adicionado à micela de ácido linoleico. Os resultados obtidos permitem concluir que de todos os antioxidantes testados o galhato de butilo é o que possibilita uma maior inibição da oxidação do ácido linoleico para as duas concentrações de antioxidantes testadas (0,1 mM e 1mM), obteve-se uma percentagem de inibição do ácido linoleico de 54,0% e 63,6%, respetivamente. O estudo comparativo da estabilização do ácido linoleico com o antioxidante de referência, o butil -hidroxitolueno, mostrou que este composto tem um poder de estabilização inferior a qualquer dos antioxidantes estudados. Os resultados deste estudo demonstraram que a utilização de compostos fenólicos, em especial o galhato de butilo, constitui uma boa alternativa para a estabilização de matrizes lipídicas, nomeadamente de combustíveis como o biodiesel.