• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권3호
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• pp.180-187
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• 2000

A moving-coil-type linear oscillatory actuator(LOA) consists of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure. The LOA system was represented by the voltage equation of coil and the mechanical equation of motion. This set of equations was manipulated in state-space form. The EMF constant kE of equation parameters in state-space form can be obtained by using the induced voltage in armature coils at open circuit test. kE and other parameters provide the system matrices and transfer function for frequency response and dynamic simulation. Voltage source inverter-fed LOA is examined aiming to compare with results of simulation.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권11호
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• pp.713-719
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• 2000

This paper presents an approach toward improving the performance of Moving Coil Type Linear Oscillatory Actuator (MC-LOA) with the application of Finite Element Method (FEM) to a simple control system. MC-LOA has an unbalanced magnetic circuit due to its asymmetric structure and there is a different flux distribution on the air-gap along the current direction. The interaction driven by two fluxes between the Permanent Magnet (PM) and the current causes the unbalanced thrust and interferes with the proper oscillation of MC-LOA. In order to solve the above problems and improve the driving performance, it is necessary to analyze the rate of the unbalanced thrust according to the current direction by using FEM. Then, the analysis results are used to determine the input currents for both directions. Controlling the input currents can be easily achieved by a simple control system, such as Pulse Width Modulation (PWM), without complex units. The validity of the approach is verified by the experimental results.

• Parasites, Hosts and Diseases
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• 제49권2호
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• pp.153-159
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• 2011

A total of 286 individuals from 3 selected communities (Areedi-Aje, Ipakodo/Ojokodo, and Ijebu-Igbo) of Ijebu-North, southwestern Nigeria were examined for Loa loa microfilaremia using finger prick blood smear, between December 2008 and March 2009. Rapid assessment procedure for loiasis (RAPLOA) was used to obtain information, from 187 Ijebu-Igbo residents, on adverse reactions experienced from retrospective treatments with ivermectin and history of eye worm. Only 33.9% of the respondents reported having had a history of eye worm while 33.2% had microfilaremia. The demographic factor of gender was not significant determinants of the prevalence (p>0.05) while age was significant (P<0.05). The highest prevalence of eye worm history and microfilaremia were recorded in 61-70 and 15-20 years of age categories, respectively. Ijebu-Igbo had 27.3% eye worm history, 32.1% microfilaremia, and the highest intensity of 140 microfilariae (mf)/ml. Ipakodo area had the highest eye worm history of 54.4% and the highest intensity of 420 mf/ml. Areedi-Aje had the highest occurrence of 45.2% microfilaremia and the highest intensity of 460 mf/ml. Predictably, Areedi-Aje and Ipakodo areas were high risk communities. The low intensity of L. loa infection with an insignificant (2.1%; P>0.05) adverse reactions from 187 subjects involved in the retrospective ivermectin administration confirmed that ivermectin delivery may be considered safe. The community-directed treatment with ivermectin (CDTI) programme was most probably responsible for the low prevalence and intensity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.742-744
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• 2001

Moving flat core LOA consists of iron flat core as a mover and electric magnet as a stator and operated by electromagnetic force between mover and stator. In a moving flat core type, it takes advantage of doing not have to be equipped with power supply device, having a lower manufacturing cost. But it has a lower linearity and precision. In this paper, a static characteristics of LOA were studied and analyzed using FEA. Experiments, electromagnetic force and inductance according to air gap and input currents, were carried by exciting coil. And we compared these results one another.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.580-582
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• 2001

In moving coil LOA, the variation of mover position and the consequent changes of coil flux path affect the coil inductance because of unbalanced magnetic circuit. Furthermore, the armature field shifts and distorts the airgap flux density distribution due to the magnet alone by a certain amount, which cause the unbalanced reciprocating force. In this paper, we propose the reduction method of armature reaction and coil inductance. The proposed LOA has the shorted ring the saturated core, the double coil, and Halbach array.

• Journal of Computational Design and Engineering
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• 제3권1호
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• pp.24-36
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• 2016

During the past decade, solving complex optimization problems with metaheuristic algorithms has received considerable attention among practitioners and researchers. Hence, many metaheuristic algorithms have been developed over the last years. Many of these algorithms are inspired by various phenomena of nature. In this paper, a new population based algorithm, the Lion Optimization Algorithm (LOA), is introduced. Special lifestyle of lions and their cooperation characteristics has been the basic motivation for development of this optimization algorithm. Some benchmark problems are selected from the literature, and the solution of the proposed algorithm has been compared with those of some well-known and newest meta-heuristics for these problems. The obtained results confirm the high performance of the proposed algorithm in comparison to the other algorithms used in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.68-70
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• 2004

This paper deals with comparison of magnetic field distribution in LOA with slotless/slot stator. We derived magnetic field solutions in terms of vector potential and cylinderical coordinates. In particular this paper accounts for slotting effect due to stator slot opening by introducing a 2-D relative permeance function. The results of predictions from the analysis are compared with corresponding finite element analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.900-902
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• 2000

A moving-coil-type linear oscillatory actuator is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The inductance of moving coil and the push/pull effect is obtained from the permeance model of LOA with the open magnetic circuit. The analytical method are verified using the 2D finite element method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.15-17
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• 1999

A voice-coil-type LOA consists of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure. We have to obtain the back-EMF constant ${\kappa}_E$ from 3D FEA and experiments, precisely. The ${\kappa}_E$ and other parameters provide the transfer function, through which is derived the frequency response characteristics. Inverter-fed LOA is examined aiming to compare with results of simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.145-147
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• 1999

A voice type Moving Coil Linear Oscillatory Actuator(MC-LOA) has unbalanced magnetic circuit structure. Its asymmetric magnetic flux distribution along the mover directions causes shifting of displacement center to one side. Therefore, this paper analyzes both thrust and displacement characteristics and settles the unbalanced flux problem by performing shape optimization. The propriety of the improved design model has been verified by dynamic analysis based on the coupling of kinetic and electric equations.