• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.1045-1051
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• 2016

This paper introduces a new optimal design method using a bacterial survival strategies for a ectromagnet of Maglev transportation vehicle. Usually, an electromagnetic suspension which has more advantages than electro dynamic suspension is used in Maglev systems. However, the structural constraints must be considered in the optimal design of an electromagnet for electromagnetic suspend system. In this paper, the optimal design method of a electromagnet based on a bacterial survival strategies optimization algorithm to design the electromagnet satisfying the structural constraints. The effectiveness of the proposed method was verified by Matlab simulations and the simulation results show that the proposed method is more efficient than conventional methods.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.695-700
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• 1997

To enhance the safety of nuclear power plants, implementation of accident management has been suggested as one of most important programs. Specially, accident management strategies are suggested as one of key elements considered in development of the accident management program. In this study, generally applicable accident management strategies to domestic nuclear power plants are identified through reviewing several accident management programs for the other countries and considering domestic conditions. Identified strategies are as follows; 1) Injection into the Reactor Coolant System, 2) Depressurize the Reactor Coolant System, 3) Depressurize the Steam Generator, 4) Injection into the Steam Generator, 5) Injection into the Containment, 6) Spray into the Containment, 7) Control Hydrogen in the Containment. In addition, the systems and instrumentation necessary for the implementation of .each strategy are also investigated.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.630-632
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• 2003

This paper describes allocation strategies of controllable loads for load aggregator in power market with the direct load control (DLC) program, which is carried out the two-way confirmation procedure. So, it is needed to the priority among the controllable loads to perform effectively and quickly the confirmation task. In this paper, allocation strategies for market operator and/or load aggregator are proposed, which are based on the basic load patterns defined in this paper. To verify the soundness of proposed strategies. case study on a sample system is performed.

• Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.38-42
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• 2005

We evaluated the effects of different feeding strategies on the growth of young Nile tilapia, Oreochromis niloticus L., in a freshwater recirculating system during summer. Each of twenty fish (Mean body weight$\pm$ SD; 37. 7$\pm$0.10 g) were randomly distributed into each of 24 tanks. Eight treatments were prepared in triplicate. Control fish were hand-fed commercial feed twice daily without starvation. The other seven treatments employed different feeding and starvation strategies ranging from I day starved and 1 day fed (1DS+ 1DF) to 7 days starved to 7 days fed (7DS+7DF). All fish survived to the end of the 44-day feeding trial. The amount of food supplied was highest for the control fish in the control. Food supplied to fish in the 3DS+3DF and 4DS+4DF treatments was significantly lower than that of fish in the 1DS+1DF and 2DS+2DF treatments, but significantly higher than that of fish in the 5DS+5DF, 6DS+6DF and 7DS+7DF treatments. The weight gain of control fish was significantly higher than that of fish in other treatments. Feed efficiency ratio (FER) for fish in the 7DS+7DF treatment was significantly higher than that of fish in the control group, but it did not differ from that of fish in the 1DS+1DF and 2DS+2DF treatments. We concluded that young Nile tilapia raised with different starvation and feeding regimes during the summer in a freshwater recirculating system did not catch up in growth to fish fed daily. However, the enhanced FER of Nile tilapia in the 7DS+ 7DF, 2DS+ 2DF, and 1 DS+ I DF treatments partly explains the compensatory growth of the fish, although their weight gain was relatively low.

• Journal of Communications and Networks
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• v.14 no.4
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• pp.352-363
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• 2012

In this paper, we study the role of cooperative relays to provide and improve secure communication rates through decodeand-forward (DF) strategies in a full-duplex multiple relay network with an eavesdropper. We consider the DF scheme as a basis for cooperation and propose several strategies that implement different versions of this scheme suited for cooperation with multiple relays. Our goal is to give an efficient cooperation paradigm based on the DF scheme to provide and improve secrecy in a multiple relay network. We first study the DF strategy for secrecy in a single relay network. We propose a suboptimal DF with zero forcing (DF/ZF) strategy for which we obtain the optimal power control policy. Next, we consider the multiple relay problem. We propose three different strategies based on DF/ZF and obtain their achievable secrecy rates. The first strategy is a single hop strategy whereas the other two strategies are multiple hop strategies. In the first strategy, we show that it is possible to eliminate all the relays' signals from the eavesdropper's observation (full ZF), however, the achievable secrecy rate is limited by the worst source-relay channel. Our second strategy overcomes the drawback of the first strategy, however, with the disadvantage of enabling partial ZF only. Our third strategy provides a reasonable compromise between the first two strategies. That is, in this strategy, full ZF is possible and the rate achieved does not suffer from the drawback of the first strategy. We conclude our study by a set of numerical results to illustrate the performance of each of the proposed strategies in terms of the achievable rates in different practical scenarios.

• Journal of Korean Elementary Science Education
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• v.31 no.1
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• pp.109-124
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• 2012

Developing pedagogical content knowledge (PCK) has been emphasized for teacher's professionalism and it should be done from systematic teacher training courses. In this study, we investigated changes of elementary pre-service teachers' PCK of science teaching and motivational strategies before and after a training course. For the analysis of pre-service teachers' PCK, their lesson plans, surveys, and interviews were collected. According to the results, in the beginning of the semester, pre-service teachers in the experimental group usually used didactic or combination of didactic and inquiry teaching strategies and a few pre-service teachers used inquiry or discovery teaching strategies when making lesson plans. However, at the end of the semester many pre-service teachers used inquiry teaching strategies in their lessons which included activities of asking students' prior knowledge, conducing experiments, finding conclusion, and comparing teachers' explanations with students' explanations. Regarding motivational strategies, in the beginning of the semester they focused using activities to create student's emotional interest in science lesson but at the end they used other strategies to create positive atmosphere for learning, capture intellectual interest in science, and connect science to students' everyday lives. The changes in pre-service teachers' PCK in the experimental group was meaningful because there was less change in pre-service teachers' PCK in the control group. This study implies the need for effective professional development programs for developing pre-service teachers' PCK.

• Journal of the Korea Society of Computer and Information
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• v.14 no.9
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• pp.157-165
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• 2009

The purpose of this study was to investigate the relationship between internet addiction in adolescent and influencing factor traits. In addition, the relationship between internet addiction and environmental coping strategies were examined. To examine the main purpose. analyzed as followed. According to the results of study. First, What have influencing factors on internet addiction? Second, How about were relationship between multidimensional factors correlation and multiregression analysis? Third, What about were prevention and coping strategies on internet addiction in adolescent period? According to the analysis with coping strategies researches, the results were presented as follows. Results showed that have positive correlation with internet use time, escape from reality, impulsivity, depression, anger control by examined results of Young addiction measure. Significant variables have influencing internet addiction with internet use time, escape from reality internet use, depression, anger control impulsivity. Based on these study results, This paper made a suggestion about prevention prescription and coping strategies of influencing factors on internet addiction in adolescent.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.212-219
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• 1999

This paper describes the NANDO VDC (Vehicle Dynamics Control) system for the vehicle stability enhancement and consists of the control strategies , computer simulation and tests on the various road surface. This VDC system controls the dynamic vehicle motion in the emergency situation such as the final oversteer/understeer andallows the vehicle to follow the course as desired by the driver. The system is based on an active yaw control and its performance verified by the test is shown. Also the comparison between the MANDO VDC System and a competitor is carried out.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.529-534
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• 1998

In this paper, control strategies of the bridge-type ZVT inverter for AC motor drive application were discussed. The topology of the ZVT inverter is analyzed with a description of the control conditions based on the load current. And a new resonant control algorithm by using load current feedback and modified SVM algorithm for the proposed ZVT inverter is proposed in order to achieve the ZVT switching condition in full control range. The detailed computer simulation and experimental results represent that ZVT and ZCT operation for the main and auxiliary switch, respectively, was achieved.

• KOREAN ASSOCIATION OF OCCUPATIONAL HEALTH NURSES
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• v.6 no.2 s.20
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• pp.45-46
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• 1999