Navegando por Assunto "Optimization"

Agora exibindo 1 - 20 de 20

Acesso aberto (Open Access)
Análise de heurísticas de implantação de hetnets densas
(Universidade Federal do Pará, 2017-02-24) ARAÚJO, Welton Vasconcelos; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
The growth of traffic in mobile networks demands a search for new technologies that can bring evolutions to the sector in question. Technologies such as heterogeneous networks (HetNets) and C-RAN (Centralized Radio Access Networks) appear as prominent solutions to this demand. However, without proper planning in the deployment of these networks, problems such as deployment cost, interference, energy efficiency and subsequent network management can lead to project unfeasibility. In this sense, this work investigates how to plan a heterogeneous network, through several heuristics in the implementation of HetNets, which will be explained later. These algorithms are evaluated in scenarios that illustrate real environments, in addition to analyzing several metrics to perform the appropriate performance evaluation of each approach. The planning of the use of centralized networks is also addressed, with a comparison with the Distributed Radio Access Network (D-RAN) model in order to show in which situations one is less costly than other. With the results, it is possible to perceive that the change in the size of the network (numbers of connected users) directly influences the results, as well as having a good indication of which technology to use in a given situation.
Acesso aberto (Open Access)
Avaliação de algoritmos evolucionários multiobjetivo para o problema de alocação de bancos de capacitores na presença de harmônicos
(Universidade Federal do Pará, 2017-08-10) KATAOKA, Vitor da Silva; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
The rapid growth of urban areas bring, as a consequence, an increase in the amount of loads connected to the distribution grids. Furthermore, the increase in the demand implies in equal raise in reactive loads, which are known to cause losses in the network. Thus, the utilities have a great challenge ahead, as the dynamics of the load require a greater effort in terms of expansion and improvements of the grid. In an attempt to mitigate the problems caused, the allocation of capacitor banks can become a practical, economical and technically robust solution. Nevertheless, it is extremely important to analyze the sizing and positioning of the banks, in order to achieve the best possible outcome. In parallel, the increasing use of nonlinear loads cause harmonics to appear in the system. When in conjunction with capacitor banks, it is possible to develop the far more dangerous phenomenon of resonance, where the amplitude of some of the harmonics goes beyond acceptable limits, resulting in undesirable effects. In this context, this work proposes a comparison between two multiobjective optimization tehcniques, NSGA-II and SPEA2, to solve the problem of sizing and placement of capacitor banks in electric energy distribution grids, considering the effects of harmonics produced by nonlinear loads.
Acesso aberto (Open Access)
Controle inteligente LQR neuro-genético para alocação de autoestrutura em sistemas dinâmicos multivariáveis
(Universidade Federal do Pará, 2008-08-30) ABREU, Ivanildo Silva; FONSECA NETO, João Viana da; http://lattes.cnpq.br/0029055473709795
In this thesis is presented a neural-genetic model, oriented to state space controllers synthesis, based on the Linear Quadratic Regulator design, for eigenstructure assignment of multivariable dynamic systems. The neural-genetic model represents a fusion of a genetic algorithm and a recurrent neural network to perform the weighting matrices selection and the algebraic Riccati equation solution, respectively. In order to a assess the LQR design, the procedure was applied in a 6th order aircraft model, 6th order doubly fed induction generator model of a wind plant and a 4th order electric circuit model which were used to evaluate the fusion of the computational intelligence paradigms and the control design method performance.The performance of the neural-genetic models are evaluated by the first and second statistics moments for the genetic algorithm, whereas the neural network is evaluated by surfaces of the energy function and of the norm of the infinity of the algebraic equation of Riccati and the results compared to the results obtained by using Schur’s Method.
Acesso aberto (Open Access)
Estratégia de resolução de situações-problema ancorada na teoria dos campos conceituais
(Universidade Federal de Mato Grosso, 2021-12) SANTOS, Rudinei Alves dos; SILVA, Francisco Hermes Santos da; DIAS, Joelson Magno; MADURO, Vanessa Pires Santos
The pandemic caused by COVID-19 led to the suspension of in-person classes, forcing those involved in the teaching and learning process to seek,as a matter of urgency, strategies that would enable the continuity of school activities. However, communication between teacher and student was relatively impaireddue to technological limitations or lack of affinity with virtual meetings. Therefore, the present work, elaborated from a qualitative approach, in the molds of the bibliographical research and anchored in the Theory of Conceptual Fields -TCF, aimed to propose a strategy of resolution of situations in the conceptual field of optimization that favors the communication between the actors in the teaching and learning process, enabling the reflection of those involved and the (re)direction of the teacher's pedagogical planning. We conclude that the strategy of solving hypotheses of the conceptual field of optimization through subtasks, in light of the TCC, is a resource that can contribute to better communication between students and teachers, especially in virtual meetings. Furthermore, we consider that the strategy discussed in this article is not exclusive to the conceptual field approach and can be tested in other conceptual fields and other areas of knowledge, as in times like these, no science-based resource should be discarded.
Acesso aberto (Open Access)
Estratégias de planejamento de Smart Grids: uma abordagem baseada em meta-heurísticas e simulação
(Universidade Federal do Pará, 2017-05-15) SANTOS, Ederson Costa dos; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
Currently, the Electric Power System undergoes major modifications, which focus on various levels and sub-levels of the generation, transmission and distribution subsystems, all of which are based on Smart Grids logic. This concept is characterized by the inclusion of new digital technologies in the electrical system, with the purpose of bringing security, speed, monitoring, among many other benefits. For the full development of Smart Grids, a lot still needs to be done in several areas of research. In this line, this work presents simulations of a Smart Grid planning model, characterizing it from protocols, which are trends for this type of network. For this, we also analyzed an optimization method, which uses intelligent algorithms to optimize devices in a Smart Grid. The proposed solution is based on the optimized allocation of equipment in acommunication network, which uses as its physical transmission medium its own electrical wiring, Power Line Communitation technology. In this network are inserted Smart Grid applications defined through IEC 61850. Thus, with this proposed model, simulations were performed in the Network Simulator-3 discrete event software. The results show a significant decrease in the quantity of equipment, maintaining the quality levels to the applications.
Acesso aberto (Open Access)
Ferramentas estatísticas aplicadas nos diferentes métodos de secagem de gelatina de peixe e no desenvolvimento de bala de goma comestível
(Universidade Federal do Pará, 2021-11-22) MATIAS, Cleidiane da Silva Araújo; REGO, José de Arimateia Rodrigues do; http://lattes.cnpq.br/4163468898377462; https://orcid.org/0000-0003-0891-6438; LOURENÇO, Lúcia de Fátima Henriques; http://lattes.cnpq.br/7365554949786769; https://orcid.org/0000-0001-5009-8235
Fish skin gelatin is a collagen product partially denatured by heat, with great potential for application in several areas of industry and thus the use of this biomaterial will add value to waste from the fishing industry and will contribute to reducing environmental impacts. The objectives of this study were: a) to optimize the drying methods by forced convection of hot air and combined with infrared radiation of gelatin extracted from fish skins, using fractional planning and rotational central composite design; b) verify the effect of different drying methods (freeze-drying, forced hot air convection, combined method, infrared radiation and refractance window) on the technological, functional, structural, thermal and rheological properties of gelatin, evaluated by ANOVA and principal component analysis; and c) prepare gummy candy using fish gelatin, cassava starch and powdered cupuaçu, through mixing planning. According to the results obtained, the desirability function showed that 59.14 °C for 12.35 h was the most effective condition for hot air convection drying and for the combined process, the optimized region was infrared temperature and drying time. 70 °C/2h with oven time/temperature of 3.51h at 70 °C. Regarding the evaluation of the five drying methods, the results were that the principal component analysis explained the accumulated variation of 99.87% of the data and that lyophilization was the method that provided the best preservation of gelatin properties, although drying convective and refractance window also showed good results, demonstrating that they are techniques with great potential for the production of gelatin. The desirability function defined the best conditions for the elaboration of the gum, in 25% of fish gelatin, 15% of cassava starch and 7% of cupuaçu powder. Therefore, the relevance of controlling the variables of the drying methods as a strategy for the production of biomaterials with standardized biochemical composition is of great interest, to obtain desirable physical, technological and functional properties necessary for the different applications of gelatin. In addition, the study suggests that there is great potential in the use of fish gelatin associated with the use of cassava and cupuaçu starch in the preparation of confectionery gum, providing better technological and functional properties of the final product
Acesso aberto (Open Access)
Metaproteômica como ferramenta tecnológica para otimização dos parâmetros de fermentação do milho para formulação de pasta alimentícia
(Universidade Federal do Pará, 2023-06-05) BAHULE, Celina Eugenio; MARTINS, Luiza Helena da Silva; http://lattes.cnpq.br/1164249317889517; LOPES, Alessandra Santos; http://lattes.cnpq.br/8156697119235191
In most developing countries, maize products are often what alleviate hunger and guarantee the livelihood of the population. Fermentation is a processing medium used to soften the corn kernel, improve flavor and digestibility, and some fermented corn products are used in the belief that they have functional properties. Maize dough, obtained by fermentation, has already been reported as having a probiotic and nutraceutical effect, however, other studies discourage its consumption, justifying it by the load and diversity of microorganisms that develop during fermentation. With the aim of studying the functional profile and looking for likely ways to optimize maize dough, a recreation of the spontaneous fermentation of corn was performed, and the formulated dough was subjected to metaproteomics analysis. A total of 53977 peptides were recovered and identified, of which more than 60% were associated with the substrate, 6% with fungi, and 34% with bacteria. Metaproteomics revealed a probable association between Actinobacteria and starch degradation enzymes in the matrix. Proteobacteria (pathogenic majority) and Firmicutes (probiotic part) coexisted and multiplied in equal proportion until the end, allied to this, the high count of mesophiles(213 x 106 CFU/g) and the timid reduction of the pH (4.42) suggested a food product not completely safe. As a way to optimize the process, the maize was autoclaved at 121oC for 20 min for enzymatic inactivation and elimination of microorganisms, and then it was inoculated with Pediococcus acidilati. Untreated maize was also inoculated. The performance of the strain both in pre-treated maize (T+I) and in untreated maize (nT+I) was considered excellent, since, in the first 24 hours, the pH values, 4.2 for nT+I samples and 4.41 for T+I samples were at levels considered safe and decreased with fermentation time. The strong correlation between the fermentation parameters when P.acidilati was used for maize inoculation, opens possibilities for the application of optimization models towards the fast, safe, and industrial production of maize dough. Indeed, metaproteomics, as culture-free and protein-based technique, allows the rapid analysis of the microbiota and the identification of active microorganisms, with the advantage of displaying and correlating the microbial profile with functionality, and are well indicated to study fermented foods quickly and concisely, demonstrating effective methods for optimization
Acesso aberto (Open Access)
Método de inversão para a obtenção dos parâmetros elétricos do solo para região amazônica baseado em medições e usando equações parabólicas
(Universidade Federal do Pará, 2015-08-20) OLIVEIRA, Romulo Augusto Nascimento de; MAGNO, Fátima Nazaré Baraúna; http://lattes.cnpq.br/8466611553866661; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
In recent years, due to the rapid development of the technology of radio access digital such as TV Digital and digital audio broadcasting, accompanied by a strong demand for these types of services, it has become of great importance the study the electric field behavior generated by radio stations who will use these technologies as well as knowledge of electrical parameters involved, which are essential in determining of the stations coverage area. This work presents a methodology of inversion through weighted least squares to obtain the equivalent electrical parameters of the vegetation and soil of a typical Amazon forest region using the model based on the formalism of parabolic equations to calculate the electric field strength received by a mobile receiver contained within in this region. To validate this methodology, measurement campaigns were conducted in Benfica, Marituba and Barcarena, State of Pará. Since in Benfica and Marituba was used a frequency of 900 MHz and Barcarena was used the frequency of 1.8 GHz. For the three cities, the measuring system consisted of a laboratory fixed and a mobile station that has been set up to measure and store the instantaneous values of the received signal. The measurements were compared with computer simulations, and so it was possible to estimate the optimal values for the electrical conductivity and relative permittivity of the vegetation that cut the road access to the cities and of the highway soil through the proposed inversion methodology. It was also made a quantitative analysis of these parameters with the values found in the literature which demonstrated the effectiveness of the proposed methodology. Finally, this work presents the results obtained with the inversion method for a rural region located in the center of Brazil, where it was found that the estimated values for soil electrical conductivity were very close to those shown in recent studies to the region.
Acesso aberto (Open Access)
Um modelo cross layer para predição de parâmetros de desempenho em redes sem fio baseados em OFDM
(Universidade Federal do Pará, 2011-11-28) MACHADO, Victor de Andrade; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
This dissertation work aims to create a mathematical model that performs the adjustment of data obtained from measurement campaigns using a prototype of a WiMAX scenario. The measurement campaigns were made at the Federal University of Para, using equipment which would enable such work. WiMAX antennas were used, one as a server, located in the building up of High Performance Network Planning Laboratory (LPRAD), and the other receiver, who was on top of a vehicle so that the points were collected. The adjustment method used was the Linear Least Squares. Through the collected data, the method is applied and their behavior is studied, checking how the optimization was effective in the cases presented. The use of relevant technology such as Internet access in some programs like NAVEGAPARÁ, the search for improvements or creation of propagation models and cross-layer analysis of the metrics used in the work, as the influence of signal to noise ratio in the loss frame, are motivating factors for this dissertation research.
Acesso aberto (Open Access)
Uma nova solução para a otimização do despacho econômico e ambiental utilizando metaheurísticas da computação bio-inspirada
(Universidade Federal do Pará, 2016) NASCIMENTO, Manoel Henrique Reis; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
Due to the significant industrial growth in the North of Brazil, especially at the Industrial Pole of Manaus (PIM), it has been an increased necessity for energy generation, which in this region is provided by thermoelectric plants (UTEs) in over 90% of its total. Thus, it became necessary the use of computational tools that help the specialists or operators of electrical systems, for making decisions about the optimal power dispatch of each generating unit that contemplate not only to reduce costs but also reduce the atmospheric pollution levels. Optimization of Economic Dispatch (ED) is one of the oldest and most important tasks in power plant management, and currently, due to growing concerns about the environment, this problem is extended to the optimization of the Economic and Environmental Dispatch (EAD). This thesis has as main objective to analyze a new proposal to solve the old optimization problem of ED and the EAD implemented by several Deterministic methods (Iteration Lambda, Quadratic Programming and Newton method) and Heuristic methods (Genetic Algorithms, Particle Swarm, Differential evolution, Simulated Annealing, Optimization by Grey Wolf and Artificial Bee Colonies) for the ED problem. Non-dominated Sorting Genetic Algorithms (NSGA II and NSGA III), were used for evaluating the problem of EAD, considering the shutdown of the generators with higher losses and thus reducing the fuel cost. The method of incremental cost and transmission losses are used to determine the best active power values for each generating unit. It was ensured the energy balance between the total generated power, the demand of the electrical system, losses and minimizing, on the other hand, the total cost of fuel, reducing emissions, and further improving efficiency not only for generators but also to UTE as a whole. Consequently, the proposed new solution has the following contributions: contemplates the turning off generation systems that have higher fuel cost, reducing the overall costs and enabling predictive maintenance on these machines. This approach also determines optimal solutions for the power output in various scenarios characteristic and not characteristic of UTEs or power plants, considering changes in active power generation and reducing greenhouse gas emissions as NOx and CO2. To explore the feasibility of the new solution proposed by this theory, it was used as a test system a set of ten (10) generating units for the case study and three sets of generators´ parameters described in the literature. They were used for demonstrating the robustness of the proposed solution considering the use of various deterministic and Bioinspired computing methods for mono-objective and multi-objective optimization. The results presented here, from an analysis of several practical examples show the advantages of the new proposed solution.
Acesso aberto (Open Access)
Otimização da detecção de formas de onda de campos eletromagnéticos emitidos por descargas atmosféricas
(Universidade Federal do Pará, 2018-01-23) LEAL, Adônis Ferreira Raiol; RAKOV, Vladimir; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
This work aims the application of optimization techniques to detect and record lightning electromagnetic waveforms. As a result of the optimization techniques developed on this Thesis, it is presented the “Lightning Detection and Waveform Storage System - (LDWSS)”. The main optimized points were: cost of the device; improvements of its detection dynamic range; development of a mobile device; possibility to detect in a multi-band way; and calibration in order to infer peak currents from remote measurements of lightning electric fields. The developed system was validated through comparison of a return stroke data in lightning triggered using the rocket-and-wire technique at the International Center for Lightning Research and Testing - ICLRT, of National Lightning Detection Network – NLDN data, and data from the Lightning Observatory in Gainesville - LOG. The main usage of the optimized system is on the investigation of lightning physics and effects, mainly in the Amazon region. As a result of using the system were obtained: a better understanding about Compact Intracloud Discharge - CID; the characteristics of ionosphere heights computed using intraclound and cloud-to-ground lightning electric field waveforms; the conception of a lightning electric field waveform database containing more than 8 thousand waveforms of different types of lightning; and the implementation of the first continuous lightning electric field measurement system in the amazon region, localized at CESIPAM, Belem, PA.
Acesso aberto (Open Access)
Otimização de nanoantenas plasmônicas para células solares orgânicas
(Universidade Federal do Pará, 2016-01-18) SILVA JÚNIOR, Marcelino Lopes Corrêa da; DMITRIEV, Victor Alexandrovich; http://lattes.cnpq.br/0684541646225359; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647
This work shows a theoretical nanoantennas study about organic solar cells of thin films, occasioning the increase in the efficiency of light absorption. The unitary organic solar cell formed by a reflector silver block, an active layer formed by the semiconductor P3HT:PCBM and a nanoantenna, also made of silver. The numerical analysis of the device is made through the Finite Element Method; the materials are analysed from the relative permittivity. Firstly, we executed the validation of the nanostructure through the numerical method. Then, we apply the geometric optimization process in the other nanoantenna models. This optimization process was based on nanoantennas geometrical parameters preserving its superficial area. Since were considered four new models of nanoantennas with different geometrical parameters, which means, conical nanoantennas, root cone, and exponential root cone 1 and 2. It was observed, from the efficiency of integrated absorption for different incidence angles and light polarization, current density and plasmonic decay that the nanoantennas, the root cone and the exponential cone 2, gave better performance compared to the other models.
Acesso aberto (Open Access)
Otimização de sistemas híbridos para a eletrificação de minirredes com fontes renováveis: aspectos de projeto, operação e gestão
(Universidade Federal do Pará, 2014-08-08) BLASQUES, Luis Carlos Macedo; PINHO, João Tavares; http://lattes.cnpq.br/0847897516772421
To avoid premature failure of hybrid power systems for electricity generation (HPSEG) and to ensure the continuity of power supply with minimum intervention of users or utilities it is essential to evaluate the design, operation and management of the system correctly. This thesis presents optimization proposals for the stages of design, operation and management of HPSEG in microgrid configuration. An operational strategy is proposed, which aims to optimize the energy dispatch of the system, identifying the best relationship, considering technical and economic aspects, between load supply exclusively via renewable sources and battery bank or exclusively via generator set, and the battery bank being charged only by renewable sources or also by the generator set. An algorithm for sizing HPSEG is also developed, using genetic algorithms and simulated annealing, metaheuristic optimization techniques, aiming to present the best system configuration, in terms of equipment, that result in the best technical and economic feasibility for a given input, defined by the user. Finally, a system management model is proposed, considering tariffing and load control systems with the objective of ensuring an appropriate relationship between energy availability of the generation system and load demand. The operational strategy proposed combines the strategies of discontinued operation of the generator set, the critical load and the optimum contribution of generator to battery charging, and the results show that there is a decrease in the system’s operational costs. Related to the sizing optimization, the proposed algorithm, when compared to other tools for the optimization of HPSEG, presents good results and is suitable for the Brazilian reality. The management model of the system proposes the establishment of consumption and demand limits suitable to the reality of isolated communities supplied by renewable generation systems and, if correctly applied, can help guarantee the system's sustainability.
Acesso aberto (Open Access)
Otimização do processo do repasse aos municípios e ao Distrito Federal – DF, oriundo da Lei 13.240, de 30 de dezembro de 2015
(Universidade Federal do Pará, 2021-08-03) FRANÇA, Fabiano Franco; LEITE, Jandecy Cabral; http://lattes.cnpq.br/7279183940171317
Public services imported a range of performance management techniques and instruments to increase the efficiency and quality of processes and services and the transparency of results, including rational planning, target setting and budget control, lean management and performance measurement. Law No. 13,240/15, which deals with the administration, disposal, transfer of property management from the Union and its use for the constitution of funds. Most public sector organizations are facing increasing scrutiny amid calls for greater accountability, monitoring and control. Thus, the objective of this dissertation is to analyze the failures of the transfer process, in the last 5 (five) years, as well as to quantify the amounts not transferred to the states. The first stage of the research consisted of a literature review. Content analysis was developed in three phases: first, a previous analysis was carried out; subsequently, the choice of documents and information obtained from the databases of the Secretariat for Heritage of the Union (SPU) was made and, finally, the material was explored with the proper interpretation of the data and discussion among the authors. The results show, as the main failures, the discontinuity of the municipalities' administrations in the disclosure of information from the Plants of Generic Values – PVG to the Regional Superintendencies of the Union's Patrimony Secretariat until 06/30 of each year; in the cataloging and sent the PVG data to the Regional Superintendencies to the General Coordinator of Heritage Assessment and Accounting – CGCAV/SPU/ME. It was found that some Regional Superintendencies either sent wrongly the list of municipalities with rights or sent updates of the PVG from previous years; sending of data (CNPJ and Current Accounts) incomplete or with divergences by Banco do Brasil; in the process in the General Coordination of Collection in the Preparation of Municipalities with Rights to Transfer; in the process in the General Coordination of Collection of Payment in the Integrated Administration System - SIAFI. It is concluded that, in addition to introducing an important improvement in the process of monitoring heritage revenues, the tool allowed us to estimate the amounts to be transferred to the Municipalities as established in art. 27 of Law No. 13,240/2015, which amended Decree-Law No. 2,398 of 12/21/1987 with the inclusion of art. 6-B.
Acesso aberto (Open Access)
Otimização do tempo de teste funcional de placa de circuito impresso montada para computador pessoal
(Universidade Federal do Pará, 2012-01-13) OLIVEIRA, Edson Farias de; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Increased competitiveness among the peer group has become increasingly important to the constant optimization of processes to consequently reduce manufacturing costs. The objective of this study is to assess the time involved in the functional testing phase of MBs produced in a company of the Industrial Pole of Manaus and propose improvements that lead to optimization of this phase. The actions taken with respect to optimizations led to the development system for capturing images to improve the analysis of downtimes and development of devices for testing, as well as the proprietary test system based on Linux to replace the previous system which relied of foreign partners. The percentage gains in the project was presented in four optimization proposals, the first being with the unification of the tests, the second with the test being performed on two board, the third with the replacement of the previous test by the system owner and end automation of the test device, which was demonstrated gains in each of the proposals. The results obtained after implementation of each proposal were positive and reinforce the need to apply scientific methods combined with creativity to achieve the optimization at any stage of the production process and closes the work suggesting ideas for future improvement of the system already optimized.
Acesso aberto (Open Access)
Otimização multicritério para despacho econômico e ambiental de usinas térmicas utilizando enxame de partículas
(Universidade Federal do Pará, 2015-03-27) AZEVEDO, Raimundo Edney dos Santos; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
One of the main objectives in the generation of electricity in thermal systems is to minimize fuel consumption through optimal allocation of power generation for each generating unit via the economic dispatch, maintaining pollutant emissions within the limits of environmental licensing, whose integrated solution is subject to a set of equality and inequality constraints. Due to environmental concerns that were developed from the emissions produced by power plants that use fossil fuels, the economic dispatch that minimizes only the total fuel cost can no longer be considered a suitable option of dispatch. This paper therefore proposes a strategy based on mathematical models to solve the problem of load dispatch considering the economic problems and the emission of pollutants, whose premises are combined into an objective function and several electrical and emission constraints using the LabView software environment. The results achieved with the application of the procedures proposed here to a thermal power plant in the city of Manaus AM, appear quite positive towards providing dispatch solutions that proved sustainable with regard to the economic and environmental aspects considered.
Acesso aberto (Open Access)
Posicionamento otimo de estações rádio base do serviço móvel celular utilizando modelo de conhecimento discreto em propagação outdoor
(Universidade Federal do Pará, 2018-12-14) GOMES, Igor Ruiz; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
A good wireless network design depends on technical, financial and what criteria you want to meet. New technologies and services, such as transmission in 5G, and the reuse of frequencies, several new studies are being done to ensure the best project for a given area. This work presents a discrete radio propagation model that uses the K-nearest neighbors classifier. The model takes into account different attributes of an environment, the studied environment was in the dependencies of the Federal University of Pará (Pará-Brazil), representing a typically Amazonian environment. For design the model, measurement campaigns were carried out in three different frequencies: 521MHz, 2100 MHz, and 2600 MHz. The study of the fading in these frequencies was made to make a generalization of frequencies to include in the model. Two scenarios to optimize the positioning of the base stations under study were carried out. The proposed model was applied in some scenarios, showing the power received at each point, in addition, tests for frequency of 700 MHz were performed to show how good the polynomial obtained was in the generalization of the frequencies.
Acesso aberto (Open Access)
Processo de secagem de Morinda citrifolia L. em secador de radiação com lâmpadas refletoras, utilizando planejamento composto central rotacional
(Universidade Federal do Pará, 2015-10-16) BARROS, Hellen Carvalho; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
Morinda citrifolia Linn, popularly known as Noni, is a plant in the Rubiaceae, family that has been used for many centuries in popular medicine. The ancestors of the Polynesians discovered the plant and there have been numerous reports of its therapeutic and nutritional properties. For that reason, it was decided to carry out a study with the fruits of the species Morinda citrifolia L., in order to encourage use of the fruit for consumption in people’s diet, as well as to confirm its functional potential after drying. In this research, the conditions for drying Noni fruits were studied, and the phenolic compounds and antioxidant activity of the extracts obtained were assessed and quantified. In the drying process a dryer with reflecting lamps was used at the laboratory scale. In analyzing the process a statistical model was used as a basis, to quantify the effects of the entry variables in the Responses, by means of regression analyses through rotational central compound planning (PCCR) with two entry variables and five levels, employing temperature and size of the pulp as entry variables and final humidity level, antioxidant capacity and free radical sequestration activity as responses. It was observed that increasing the drying temperature led to a decrease in the final humidity level of Morinda citrifolia L fruits.The values of the responses observed varied from 0,01 a 3,50 bs, for drying; 1,32% a 38,8%, and 12,54 to 26,56(mg Eag/g) for phenolic levels.Within the experimental domain, only the variable of the isolated entry X1 (temperature) in the linear and quadratic forms were statistically influential on the Xbsresponse variable.
Acesso aberto (Open Access)
Redução de ordem de modelos matemáticos lineares usando algoritmos genéticos
(Universidade Federal do Pará, 2012-08-07) FERREIRA, André de Oliveira; BARREIROS, José Augusto Lima; http://lattes.cnpq.br/1246564618922453
This dissertation presents the order reduction problem of dynamic models, from the optimization viewpoint by genetic algorithm. An objective function, obtained from the norm of the coefficients of the numerator of the error transfer function among the original and reduced model, is minimized by a genetic algorithm, with consequent calculation of the parameters of the reduced model. The procedure is applied to some examples that demonstrate the validity of the approach.
Acesso aberto (Open Access)
Solução para o despacho econômico ambiental de um sistema de geração térmica por recozimento simulado
(Universidade Federal do Pará, 2018-02-27) BRITO JÚNIOR, Jorge de Almeida; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
In recent years, population and government concerns about environmental protection have increased. At the same time, the use of fossil fuels to the production of electricity is still high, due to the high availability of this kind of energy and the consolidated technology of the thermal plants. In that context, it has become increasingly common to adopt methodologies to optimize the operation of thermoelectric plants, not only in terms of fuel costs, but also the emissions of pollutants generated, with a positive impact on the reduction of environmental pollution for electric power generation by thermal systems based on fossil fuels. This process establishes the need for research in the field of energy planning, usually based on the application of optimization methods that consider the two objectives mentioned in an integrated way. Optimization tools based on metaheuristic characteristics, such as simulated annealing, are well suited to these types of problems. In this context, the aim of this PhD thesis was to apply multiobjective optimization in the environmental economic dispatch (DEA) of thermal plants using simulated annealing, comparing the results obtained with other metaheuristic techniques. This tool was used with an aptitude function that involves two objectives (cost and emissions), to find the optimal result, taking into account the shutdown of less efficient engines, thus ensuring the reduction of financial costs and pollution.