Contribuições da pesquisa operacional para gestão da produção e operações : uma análise exploratória da literatura

This research aims to investigate the evolution presented during three decades (1980, 1990 and 2000) of using the tools of Operations Research (OR) as a suport to decision making in Production Operation Management (POM). Hypothesis tests were made to verify the proportional growth of a given area over the decades to the detriment of the areas of facility layout, capacity planning, production scheduling and inventory management. Six journals were selected and from them more than 800 articles were used for classification and analysis in the grounds of review. It also discussed possible ways for future research and comparisons are made with other papers of literature review. As a result, it was found that areas of heuristics and simulation showed a greater quantity of contributions in all POM areas of this study

Uso de técnicas de otimização baseadas em derivadas como suporte do planejamento operacional de redes de distribuição de energia elétrica

The usual programs for load flow calculation were in general developped aiming the simulation of electric energy transmission, subtransmission and distribution systems. However, the mathematical methods and algorithms used by the formulations were based, in majority, just on the characteristics of the transmittion systems, which were the main concern focus of engineers and researchers. Though, the physical characteristics of these systems are quite different from the distribution ones. In the transmission systems, the voltage levels are high and the lines are generally very long. These aspects contribute the capacitive and inductive effects that appear in the system to have a considerable influence in the values of the interest quantities, reason why they should be taken into consideration. Still in the transmission systems, the loads have a macro nature, as for example, cities, neiborhoods, or big industries. These loads are, generally, practically balanced, what reduces the necessity of utilization of three-phase methodology for the load flow calculation. Distribution systems, on the other hand, present different characteristics: the voltage levels are small in comparison to the transmission ones. This almost annul the capacitive effects of the lines. The loads are, in this case, transformers, in whose secondaries are connected small consumers, in a sort of times, mono-phase ones, so that the probability of finding an unbalanced circuit is high. This way, the utilization of three-phase methodologies assumes an important dimension. Besides, equipments like voltage regulators, that use simultaneously the concepts of phase and line voltage in their functioning, need a three-phase methodology, in order to allow the simulation of their real behavior. For the exposed reasons, initially was developped, in the scope of this work, a method for three-phase load flow calculation in order to simulate the steady-state behaviour of distribution systems. Aiming to achieve this goal, the Power Summation Algorithm was used, as a base for developing the three phase method. This algorithm was already widely tested and approved by researchers and engineers in the simulation of radial electric energy distribution systems, mainly for single-phase representation. By our formulation, lines are modeled in three-phase circuits, considering the magnetic coupling between the phases; but the earth effect is considered through the Carson reduction. It s important to point out that, in spite of the loads being normally connected to the transformer s secondaries, was considered the hypothesis of existence of star or delta loads connected to the primary circuit. To perform the simulation of voltage regulators, a new model was utilized, allowing the simulation of various types of configurations, according to their real functioning. Finally, was considered the possibility of representation of switches with current measuring in various points of the feeder. The loads are adjusted during the iteractive process, in order to match the current in each switch, converging to the measured value specified by the input data. In a second stage of the work, sensibility parameters were derived taking as base the described load flow, with the objective of suporting further optimization processes. This parameters are found by calculating of the partial derivatives of a variable in respect to another, in general, voltages, losses and reactive powers. After describing the calculation of the sensibility parameters, the Gradient Method was presented, using these parameters to optimize an objective function, that will be defined for each type of study. The first one refers to the reduction of technical losses in a medium voltage feeder, through the installation of capacitor banks; the second one refers to the problem of correction of voltage profile, through the instalation of capacitor banks or voltage regulators. In case of the losses reduction will be considered, as objective function, the sum of the losses in all the parts of the system. To the correction of the voltage profile, the objective function will be the sum of the square voltage deviations in each node, in respect to the rated voltage. In the end of the work, results of application of the described methods in some feeders are presented, aiming to give insight about their performance and acuity

Uso de técnicas de otimização baseadas em derivadas como suporte do planejamento operacional de redes de distribuição de energia elétrica

The usual programs for load flow calculation were in general developped aiming the simulation of electric energy transmission, subtransmission and distribution systems. However, the mathematical methods and algorithms used by the formulations were based, in majority, just on the characteristics of the transmittion systems, which were the main concern focus of engineers and researchers. Though, the physical characteristics of these systems are quite different from the distribution ones. In the transmission systems, the voltage levels are high and the lines are generally very long. These aspects contribute the capacitive and inductive effects that appear in the system to have a considerable influence in the values of the interest quantities, reason why they should be taken into consideration. Still in the transmission systems, the loads have a macro nature, as for example, cities, neiborhoods, or big industries. These loads are, generally, practically balanced, what reduces the necessity of utilization of three-phase methodology for the load flow calculation. Distribution systems, on the other hand, present different characteristics: the voltage levels are small in comparison to the transmission ones. This almost annul the capacitive effects of the lines. The loads are, in this case, transformers, in whose secondaries are connected small consumers, in a sort of times, mono-phase ones, so that the probability of finding an unbalanced circuit is high. This way, the utilization of three-phase methodologies assumes an important dimension. Besides, equipments like voltage regulators, that use simultaneously the concepts of phase and line voltage in their functioning, need a three-phase methodology, in order to allow the simulation of their real behavior. For the exposed reasons, initially was developped, in the scope of this work, a method for three-phase load flow calculation in order to simulate the steady-state behaviour of distribution systems. Aiming to achieve this goal, the Power Summation Algorithm was used, as a base for developping the three phase method. This algorithm was already widely tested and approved by researchers and engineers in the simulation of radial electric energy distribution systems, mainly for single-phase representation. By our formulation, lines are modeled in three-phase circuits, considering the magnetic coupling between the phases; but the earth effect is considered through the Carson reduction. Its important to point out that, in spite of the loads being normally connected to the transformers secondaries, was considered the hypothesis of existence of star or delta loads connected to the primary circuit. To perform the simulation of voltage regulators, a new model was utilized, allowing the simulation of various types of configurations, according to their real functioning. Finally, was considered the possibility of representation of switches with current measuring in various points of the feeder. The loads are adjusted during the iteractive process, in order to match the current in each switch, converging to the measured value specified by the input data. In a second stage of the work, sensibility parameters were derived taking as base the described load flow, with the objective of suporting further optimization processes. This parameters are found by calculating of the partial derivatives of a variable in respect to another, in general, voltages, losses and reactive powers. After describing the calculation of the sensibility parameters, the Gradient Method was presented, using these parameters to optimize an objective function, that will be defined for each type of study. The first one refers to the reduction of technical losses in a medium voltage feeder, through the installation of capacitor banks; the second one refers to the problem of correction of voltage profile, through the instalation of capacitor banks or voltage regulators. In case of the losses reduction will be considered, as objective function, the sum of the losses in all the parts of the system. To the correction of the voltage profile, the objective function will be the sum of the square voltage deviations in each node, in respect to the rated voltage. In the end of the work, results of application of the described methods in some feeders are presented, aiming to give insight about their performance and acuity

Diagnóstico operacional de lagoas de estabilização

This work intends to develop an approach based through scientific criteria in the operational diagnosis of ponds of stabilization, starting from analyses accomplished in loco and in laboratory of 78 systems of sewer treatment through ponds of stabilization in the State of Rio Grande do Norte. The objectives of the research are: to map, to evaluate and to diagnose the operational acting of the ponds of stabilization of the state of Rio Grande do Norte, through visits in loco and analyses laboratory; to build a SIG, through the map rain, locate the points of releases of sewages of the systems of existent ponds in Rio Grande do Norte, as well as operational data and his/her respective efficiency diagnosis in the removal of BOD and Coliforms Termotolerantes; to evaluate, in real scale, three systems of ponds of stabilization of RN in the operational efficiency for the parameters BOD5, COD, pH, Temperature, OD and Coliforms Termotolerantes. Of 78 ETEs of appraised RN just, 9% or 7 had maximum concepts in what concerns the removal of BOD and Coliforms Termotolerantes and 41% or 32, they had the worst concepts in term of operational efficiency. The flowing concentrations ETEs of RN of BOD and Coliforms were of 410mg/L and 2,50x107UFC/100ml, the predominant configuration is of the type F1+M1+M2, the relationship BOD/COD revealed for the sewer tributary characteristic biodegradable high. For the study of case of 3 ETEs, the best operational efficiencies in decreasing order were: Cidade (Municipal district), it Roça (State) and São Miguel (SAAE). The removals of final BOD were 51,6mg/L; 108,27mg/L and 62,6mg/L, tends efficiency of 82%; 74% and 81%. In term of coliforms removal in the final effluentes were 1,90x103UFC/100ml; 1,50x104UFC/100ml and 3,10x104UFC/100ml, tends efficiencies of 99,99%; 99,95% and 99,90%. In what it concerns the practice of agricultural reúso of cultures consumed raw, none of 3 ETEs assisted the parameters of the Resolution CONAMA 357/05, for other reúso practices, all assisted the categories B and C of OMS. For release in body receiving ETE Cidade just, they assist the demands of the resolution of CONAMA 357/05, by study of purification solemnity of the receiving body. The maintenance lack and operation; exclusive operator in ETEs and operation knowledge was the contributory factors for the operational fall in appraised ETEs of RN

A influência da prática meditativa sobre parâmetros psicofisiológicos e tarefas de memória operacional em indivíduos saudáveis

Meditation is described as a method for improving attention and promoting psychological and emotional stability, presenting favourable results on memory and stress tolerance as well. Studies have shown differences in physiological and psychological measurements between meditators and non-meditators. The aim of this study was to investigate the influence of regular meditation practice on working memory, psychological measurements and quality of life of healthy practitioners. We carried out a comparative study with meditators and non-meditators. Working memory tests and standard inventories of life quality, anxiety, mood, sleep quality, depression and stress were applied. Our study showed that meditators presented better scores in parameters indicative of life quality, mood, depression and stress when compared with non-meditators. Moreover, there was a trend in best performance of meditators in memory tasks (forward digit span task and Hanoi tower). These findings corroborate other studies showing that regular meditation can provide an improvement in general quality of life and affecting positively the behavioral and attentional functions in individuals

Sistema operacional e biblioteca de funções para plataformas MPSOC: um estudo de caso para simuladores de reservatórios

The increasingly request for processing power during last years has pushed integrated circuit industry to look for ways of providing even more processing power with less heat dissipation, power consumption, and chip area. This goal has been achieved increasing the circuit clock, but since there are physical limits of this approach a new solution emerged as the multiprocessor system on chip (MPSoC). This approach demands new tools and basic software infrastructure to take advantage of the inherent parallelism of these architectures. The oil exploration industry has one of its firsts activities the project decision on exploring oil fields, those decisions are aided by reservoir simulations demanding high processing power, the MPSoC may offer greater performance if its parallelism can be well used. This work presents a proposal of a micro-kernel operating system and auxiliary libraries aimed to the STORM MPSoC platform analyzing its influence on the problem of reservoir simulation

A utilização da pesquisa operacional para o gerenciamento dos leitos em um hospital particular: estudo de caso baseado em simulação computacional

The hospital is a place of complex actions, where several activities for serving the population are performed such as: medical appointments, exams, surgeries, emergency care, admission in wards and ICUs. These activities are mixed with anxiety, impatience, despair and distress of patients and their families, issues involving emotional balance both for professionals who provide services for them as for people cared by them. The healthcare crisis in Brazil is getting worse every year and today, constitutes a major problem for private hospitals. The patient that comes to emergencies progressively increase, and in contrast, there is no supply of hospital beds in the same proportion, causing overcrowding, declines in the quality of care delivered to patients, drain of professionals of the health area and difficulty in management the beds. This work presents a study that seeks to create an alternative tool that can contribute to the management of a private hospital beds. It also seeks to identify potential issues or deficiencies and therefore make changes in flow for an increase in service capacity, thus reducing costs without compromising the quality of services provided. The tool used was the Computational Simulation –based in discrete event, which aims to identify the main parameters to be considered for a proper modeling of this system. This study took as reference the admission of a private hospital, based on the current scenario, where your apartments are in saturation level as its occupancy rate. The relocation of project beds aims to meet the growing demand for surgeries and hospital admissions observed by the current administration.

Análise de confiabilidade de um moto-ventilador centrífugo: aplicação no sistema de pressurização de subestação industrial para garantia da segurança operacional na indústria petroquímica

The need of the oil industry to ensure the safety of the facilities, employees and the environment, not to mention the search for maximum efficiency of its facilities, makes it seeks to achieve a high level of excellence in all stages of its production processes in order to obtain the required quality of the final product. Know the reliability of equipment and what it stands for a system is of fundamental importance for ensuring the operational safety. The reliability analysis technique has been increasingly applied in the oil industry as fault prediction tool and undesirable events that can affect business continuity. It is an applied scientific methodology that involves knowledge in engineering and statistics to meet and or analyze the performance of components, equipment and systems in order to ensure that they perform their function without fail, for a period of time and under a specific condition. The results of reliability analyzes help in making decisions about the best maintenance strategy of petrochemical plants. Reliability analysis was applied on equipment (bike-centrifugal fan) between the period 2010-2014 at the Polo Petrobras Guamaré Industrial, situated in rural Guamaré municipality in the state of Rio Grande do Norte, where he collected data field, analyzed historical equipment and observing the behavior of faults and their impacts. The data were processed in commercial software reliability ReliaSoft BlockSim 9. The results were compared with a study conducted by the experts in the field in order to get the best maintenance strategy for the studied system. With the results obtained from the reliability analysis tools was possible to determine the availability of the centrifugal motor-fan and what will be its impact on the security of process units if it will fail. A new maintenance strategy was established to improve the reliability, availability, maintainability and decreased likelihood of Moto-Centrifugal Fan failures, it is a series of actions to promote the increased system reliability and consequent increase in cycle life of the asset. Thus, this strategy sets out preventive measures to reduce the probability of failure and mitigating aimed at minimizing the consequences.