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Leitao P.,Polytechnic Institute of Braganca | Marik V.,Czech Technical University | Vrba P.,Czech Technical University
IEEE Transactions on Industrial Informatics | Year: 2013

Industrial agents technology leverages the benefits of multiagent systems, distributed computing, artificial intelligence techniques and semantics in the field of production, services and infrastructure sectors, providing a new way to design and engineer control solutions based on the decentralization of control over distributed structures. The key drivers for this application are the benefits of agent-based industrial systems, namely in terms of robustness, scalability, reconfigurability and productivity, all of which translate to a greater competitive advantage. This manuscript monitors the chronology of research and development of the industrial applications of multiagent and holonic systems. It provides the comprehensive overview of methodologies, architectures and applications of agents in industrial domain from early nineties up to present. It also gives an outlook of the current trends as well as challenges and possible future application domains of industrial agents. © 2005-2012 IEEE. Source

Leitao P.,Polytechnic Institute of Braganca
Studies in Computational Intelligence | Year: 2013

The demand for large-scale systems running in complex and even chaotic environments requires the consideration of new paradigms and technologies that provide flexibility, robustness, agility and responsiveness. Multiagents systems is pointed out as a suitable approach to address this challenge by offering an alternative way to design control systems, based on the decentralization of control functions over distributed autonomous and cooperative entities. However, in spite of their enormous potential, they usually lack some aspects related to interoperability, optimization in decentralized structures and truly self-adaptation. This paper discusses a new perspective to engineer adaptive complex systems considering a 3-layer framework integrating several complementary paradigms and technologies. In a first step, it suggests the integration of multi-agent systems with service-oriented architectures to overcome the limitations of interoperability and smooth migration, followed by the use of technology enablers, such as cloud computing and wireless sensor networks, to provide a ubiquitous and reconfigurable environment. Finally, the resulted serviceoriented multi-agent system should be enhanced with biologically inspired techniques, namely self-organization, to reach a truly robust, agile and adaptive system. © Springer-Verlag Berlin Heidelberg 2013. Source

Silva J.A.C.,Polytechnic Institute of Braganca | Schumann K.,Chemiewerk Bad Kostritz | Rodrigues A.E.,University of Porto
Microporous and Mesoporous Materials | Year: 2012

The sorption equilibrium of CO 2 and CH 4 in binderless beads of 13X zeolite has been investigated between 313 and 373 K and pressure up to 4 atm. The amount adsorbed of CO 2 and CH 4 is around 5.2 mmol/g ads and 1.2 mmol/g ads, respectively, at 313 K and 4 atm. Comparing these values with the ones in literature the value of CO 2 is 20% higher than in CECA 13X binder pellets. It is also found that isotherms are pronounced Type I for CO 2 and almost linear for CH 4. The CO 2 isotherms were modeled using a simple deviation from Langmuir isotherm that takes into account interaction between adsorbed molecules at adjacent sites (Fowler model) suggesting a moderate repulsion. Henry's constants range from 143 to 11.1 mmol/g ads.atm for CO 2 and 0.45 to 0.27 mmol/g ads.atm for CH 4 between 313 and 373 K, respectively. The heats of sorption at zero coverage are 43.1 kJ/mol for CO 2 and 9.2 kJ/mol for CH 4. The sorption kinetics has been investigated by the Zero-Length Column technique (ZLC). Recipes to analyze ZLC desorption curves in pellets of adsorbents are reviewed and it is derived a criteria which indicates that for the sorption rate be measured macroscopically the time of the experiment (that should be above a few seconds) is directly calculated with the following expression: t0.1≥7.02×10-2rc2Dc. Based on such criteria it is shown that crystal diffusivity of CO 2 in 13X can be measured macroscopically by ZLC, being the same measurement for CH 4 practically impossible. The crystal diffusivity of CO 2 measured experimentally is 5.8 × 10 -15 m 2/s and 1.3 × 10 -15 m 2/s at 373 and 313 K, respectively. These values are comparable to the ones measured by a frequency response and pulse chromatography techniques reported in literature. The ZLC desorption curves for CH 4 were measured under an equilibrium regime. © 2012 Elsevier Inc. All rights reserved. Source

Ramalhosa E.,Polytechnic Institute of Braganca
Advances in food and nutrition research | Year: 2011

Honey is a natural product with recognized physical and chemical properties, which contribute to its biological activity. However, honey is currently being sold at low prices, making it imperative to find alternatives to make apiculture a viable national enterprise. One of these alternatives could be mead production. Despite the excellent properties of honey, mead production faces several problems, namely, delays and "pouts" fermentations, lack of product uniformity, and production of yeast off-flavors. Many factors might be related with these problems, such as honey variety, temperature, medium composition (vitamin and nitrogen content), fermentative yeast, and pH. Due to all these factors, mead production has decreased over the years. To overcome this situation, more research is needed to optimize the production of this beverage. This chapter presents a comprehensive review of previous research on mead production. It will focus on honey characterization and mead production. The first section covers honey composition and the way this affects honey properties, as well as important parameters that are indicators of honey quality. The second section discusses mead production, including fermentative microorganisms, fermentation conditions, and required postfermentation adjustments and maturation conditions. The final section focuses on the problems that must be surpassed and what the future holds for mead production. Copyright © 2011 Elsevier Inc. All rights reserved. Source

Alves M.J.,Polytechnic Institute of Braganca
Current topics in medicinal chemistry | Year: 2013

The present review reports the antifungal activity of mushroom extracts and isolated compounds including high (e.g. peptides and proteins) and low (e.g. sesquiterpenes and other terpenes, steroids, organic acids, acylcyclopentenediones and quinolines) molecular weight compounds. Most of the studies available on literature focused on screening of antifungal activity of mushroom extracts, rather than of isolated compounds. Data indicate that mushroom extracts are mainly tested against different Candida species, while mushroom compounds are mostly tested upon other fungi. Therefore, the potential of these compounds might be more useful in food industry than in clinics. Oudemansiella canarii and Agaricus bisporus methanolic extracts proved to be the most active mushroom extracts against Candida spp. Grifolin, isolated from Albatrellus dispansus, seemed to be the most active compound against phytopathogenic fungi. Further studies should be performed in order to better understand the mechanism of action of this and other antifungal compounds as well as safety issues. Source

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