Repositório RCAAP

The changes brought by the constant technological evolution, improvement of production processes with high competitiveness among the companies form a scenario where people are subjected to stressful situations. Occupational stress affects people regardless of age, gender and role within the company. Governments and companies expend a lot of resources because of sick leave, benefit payments, troubled professional relationships and low levels of productivity due to the effects of stress at work. In addition, prolonged exposure to stress and the lack of mechanisms to manage it can cause serious health problems of people. On the other hand, current research shows that digital games have positive potential for coping with stress. However, systems or stress management programs that suggest the action of playing as a way to lower stress levels, do not specify which games should be used. This choice is sometimes in charge of the patient himself. Playing at the workplace is different from playing at home. It is important that the choice of games for coping with occupational stress is made based on workplace environmental characteristics, employee, game and supervised by a Psychologist to avoid the unwanted consequences of using these games. Thus, there is a need to provide psychologic tools that assist them in such task. Researches in the context of digital games and stress have focused on proving that digital games can be used when coping with stress. However, no studies were found to address this goal. This study therefore aims to propose a strategy for the development of search engines and digital entertainment games for coping with occupational stress. The strategy proposed here is based on the relationship among the information coping strategies, personality traits, games preferences, stressors and restrictions at work environment. This information characterizes the company and the employee in the context of occupational stress. The strategy can be used as a guide in the development of tools to assist the Psychologist in the task of suggesting game.

The computational and empirical modelling of geophysical phenomena, such as F region zonal plasma drifts, is a basic tool for the understanding and forecasting of effects that have great social-economic impact on the human activities. This work proposes, develops and implements a model, based on Computer Aided Geometric Design techniques, to F region zonal plasma drifts over Jicamarca, Peru. Amongst the developed models, that which shows itself as having the greatest success uses Bézier curve fitting with least-square methods. Other models used, such as wavelet theory, minimax and Kalman filters, had also been attempted, but without the same success. The main data source was the incoherent scatter radar measurements installed in the Jicamarca Radio Observatory. This data was preprocessed in order to carry out error handling and to improve its statistical quality. The preprocessed data formed the basis to the quiet and disturbed time zonal dritfs models construction. The models had been implemented in the functional programming language Objective Caml, an efficient, concise and well tailored programming language in numerical calculus.

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The next generation of high-speed mobile/wireless networks will support multimedia applications. The support of such applications imposes Quality of Service (QoS) requirements that have been considered very restrictive in this network environment due to the difficulty of managing the scarce bandwidth, the droppings because of handoff and blocking calls. Thus, in this work, we propose alternative schemes of CAC (Call Admission Control) combined with adaptive bandwidth reservation schemes of adjacent cells, in an end-to-end approach. The results obtained from performance studies based on modeling and simulation, demonstrated that the proposed schemes called Directed Reserve (RDir) and Total Reserve (RT), have presented the lowest CDP (Call Dropping Probability), when compared with similar schemes described in the literature. Thus, these schemes are capable to promote the maintenance of the accepted calls within the network and improve the quality of service of the cellular mobile networks with support to multimedia traffic

Many computer algebra systems have already been proposed and implemented. Most of them are implemented in or even implement languages without the referential transparency property, making it difficult, if not impractical, to reason about algebra programs. This thesis presents a computer algebra system implemented as a library in the Haskell programming language, a modern functional language with the desired referential transparency property. The author presents the foundations and basic algorithms for manipulation of algebraic expressions in a declarative context, compatible with Mathematics. The adequacy of the constructs provided by the Haskell programming language is considered when implementing such a library in a modular way, so that it can be easily extended with the inclusion of new algebraic formulas and manipulations. Such extensions should keep compatibility with prior versions of the library. This work also contributes for showing that modern functional languages like Haskell are viable for day to day programming, even beating conventional languages in some aspects, like level of abstraction.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The evidences demonstrate that the inorganic phosphate increase is strongly associated with the weakness of the contractile mechanism, due to attractiveness with the ion calcium liberated by the sarcoplasmic reticulum and the formation of the calcium phosphate. Experimental studies related to the effect of the inorganic phosphate reacting with ion calcium, usually in vitro are accomplished, in other words, with reactions that could omit substances with interfere in the conditions in vivo during the muscular contraction. It is still necessary to observe the high concentration of inorganic phosphate drives the precipitation of calcium phosphate and if these reactions can be verified in vivo, as well as, to present a methodology that allows reproductibility for futures research projects that can associate this precipitation affects, or can not, the muscular contraction. This study order to evaluated the inorganic phosphate, induced through the injection of potassium phosphate in vivo, it causes precipitation with the calcium serum, generating the product denominated insoluble phosphate of calcium and, which ideal amount to be injected indeed for such a precipitation to happen in vivo. The protocol used in that procedure consisted of the use of intraperitoneal injection of potassium phosphate, in rats Wistar separated randon and equal distributed in seven groups of seven animals, where the Group I was denominated of control and injected 0,5 ml of physiologic solution (NaCl 0,9%) and the Groups II to VII with the following doses, respectively: 0,5, 1,5, 2,5, 5,0, 7,5 g e 10,0 mg/kg. After the injection of potassium phosphate, the blood was collected of the inferior cava vein and submitted the biochemical evaluation of the creatinin, urea, calcium and inorganic phosphate. The results demonstrated that after to the regression of analysis, none of the models was significant statistically (p0,05) to represent some urea variation and of the creatinin in function of the variations of the doses of inorganic phosphate. In relation to the inorganic phosphate, the model sigmoidal of four parameters presents an excellent adjustment degree to the data and with difference significant statistically among the doses of potassium phosphate (p<0,0147). The calcium serum presented difference significant statistically (p<0,0069) among the treatment it controls and the treatment that corresponds to the application of 5,0 mg/kg of phosphate potassium. From of that value there is a tendency to the stabilization of the presented answer, where we didn't find differences significant statistically among the doses of potassium phosphate. With these results we can conclude that the potassium phosphate is a substance capable to cause precipitation of calcium serum without any lesion in the animals and that the ideal amount of potassium phosphate to be injected for increase of the concentration of inorganic phosphate and decrease of the calcium serum is of 5,0 mg/kg, and you dose superiors or inferior don't present effects in the concentration of calcium serum due to precipitation with the inorganic phosphate.

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The purpose of this study was investigate the measurement techniques of human movement and to develop a system capable of capturing and reconstructing the movement trajectory on real world. The devised system uses video cameras to record the movement and a computer program to process video footage assessing the movement trajectory and calculating its kinematical variables. Those data are showed by the program as graphics or animation which simulates the reconstructed movement. To reach these objectives, the system used techniques from image processing, computer vision and anthropometric models. In the end of this work, it is exhibited an experimental evaluation of the precision and accuracy of the system and some case studies to show its potential.

The incipient technology of wireless access networks of the IEEE 802.16 Standard aggregates to the BWA systems many advantages over concur technologies, such as radio signal wide coverage, even in difficult access regions or needy of conventional infrastructure of network, as the case of some urban and rural areas of Brazil. Moreover, enables access to the Internet in last mile with high transmission rates, attending to the more several requisites of the data, voice and video applications with minor cost in comparison to others available alternatives. Meanwhile, this technology not specifies how the packages or service flows should be the scheduled in the MAC layer. Thus, this study compares the use of mechanisms for scheduling that approximates the ideal GPS scheduler to support the provision of QoS on IEEE 802.16 PMP network. The modeling and simulation based results evidence that the considered mechanisms WRR and WF2Q get good results in the support to the provision of QoS in this network.

In globalization times, the international trade becomes part of day-by-day of the people. With this continuous increasing of the importation and exportation activities, the logistic chain starts to have vital and indispensable role. Containers Terminal is an important component of the international logistic chain; multimodal interface that handles mainly with goods of the maritime modal (ship), become one of the responsible by the agility and the cost that the goods that are destined and came from foreign commerce reaches the final consumer. One of the more important tasks of the Container Terminal operational activities is the Stowage Planning, which can be characterized as a work of the optimize resources and schedules. The large amount of variables in these optimizations becomes decision support tools indispensable. Genetic Algorithms (GA) have being successfully used in complex problems, mainly which deterministic modeling is difficult, or if this approach brings computational times that becomes solutions infeasible. The proposal of this work was the implementation of the GA that could enclose the Container Terminal reality, with the complete and the large number of variables and restrictions known for the Stowage Planning process. In the GA developed was used also a routine that seems the local search process, called repaired routine, intending to speed up the convergence to the feasible solutions space, improving the general performance. With the container set used, the simulations results showed that the employed technique is appropriate, considering the characteristics of the best solutions and the computational times. Future works suggested would become the proposal still more adherent to daily run of the Container Terminal.

The compressed air systems represent plot expressive of energy consumption of an industrial plant. However, the lack of an appropriate project and a regular maintenance causes reduction in the overall performance featuring a constant source of waste. This fact guided the subject of this dissertation research, which is directed towards the development and application of techniques for analysis of the energy efficiency of compressed air systems. The analysis will be addressed more specifically to the study of the compressor installed in the laboratory systems driving the Faculty of Electrical Engineering of the Federal University of Uberlândia. Within this focus, the activities developed and presented in this document include issues related to energy conservation, presentation of the prototype, its analysis through digital simulations in the field of time, method of diagnosis energy, and finally, a case study obtained the prototype.

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