• Journal of the Korea Society of Computer and Information
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• v.21 no.4
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• pp.25-30
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• 2016

We consider energy efficient transmit and receive strategy for a delay sensitive data. More specifically, we investigate an energy optimum scheduling characteristics for the 2 user interference channel where each user interferes to each other. First, we determine the optimum transmission rate region each individual user may have for optimum transmission. Next, we consider the optimum transmission region of two users together. Shortest path algorithm can be used for further reduction of search space. Eventually, we can reduce computational complexity. We then examine the performance of the optimum transmission strategy for various system environments.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.9
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• pp.623-635
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• 1987

A new suboptimal PWM is proposed, intended particularly for the reduction of acoustic noise and harmonics of the output current in the inverter-fed induction motor drive system. This strategy is based of the Regular PWM and applied optimal techniqe. And it could solve a problem that computation time is very much when switching strategy is determined at the Optimal PWM. In case that the number of switching increases infinitely, this strategy could determine the switching pattern, and can realize Online, Real time of microprocessor. Also, this strategy is applied to 1(Hp), three phase induction motor, and compared with the other PWMs. From the results, the validity of this strategy could be verified.

• Culinary science and hospitality research
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• v.4
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• pp.347-367
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• 1998

It is difficult to make which customers want in restaurant industry because of IMF situation. Therefore, utilization of service marketing is needed by best effect through least investment in restaurant industry. The background of restaurant industry is not directly related to the improvement of tourism industry. We should give a hand to tourism and restaurant industry by holding international events. so the way of thinking among people is changing. And importing of famous foreign brand and opening shops are accellerating the improvement of tourism and restaurant industry. In this perspective, improvement factors of restaurant industry are as follows : the increase of pst time, the increase of disposable income, the increase of woman's having jobs and double income, requirement of people about health food, the increase of nuclear family, and the change of viewpoint among people. This restaurant industry is service industry, and it sells invisible service except the aspect of selling menu. In addition, in terms of menu, price reduction strategy should be done by cost reduction and restructuring. The ultimate purpose of marketing is to increase sales and to do this we should increase the number of customers in shops. That means we should create new customers and try to attract customers who used to be regular in the shops. Therefore, the demonstration of management ability and positive reaction is really needed. So the most important things in marketing are as follows: proper strategy for double consumption, increasing the number of customers through new specific menu, menu life cycle according to menu item, menu development by considering customer, making recipe, enhancement of product quality and cost reduction by customer's opinion. We should concentrate on national menu first, and try to develop menu for international market. It is absolutely needed that we set up the menu product strategy through menu marketing with various products and constant study related to menu marketing is to be done.

• Journal of the Korean Electrochemical Society
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• v.18 no.2
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• pp.81-85
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• 2015

A method for degradation of the perchlorate anion ($ClO{_4}^-$) has been studied using electrochemically generated zero-valent iron (ZVI) deposited on a porous carbon electrode. The first strategy of this study is to produce the ZVI via the electrochemical reduction of iron (II) on a porous carbon electrode coated with a conducting polymer, instead of employing expensive $NaBH_4$. The present method produced well distributed ZVI on conducting polymer (polypyrrole thin film) and increased surface area. ZVI surface can be regenerated easily for successive reduction. The second strategy is to apply a mild reducing condition (-0.3 V) to enhance the efficiency of the degradation of perchlorate with ZVI without the evolution of hydrogen. The electrochemically generated ZVI nanoparticles may offer an alternative means for the complete destruction perchlorate without evolution of hydrogen in water with high efficiency and at low cost.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1177-1186
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• 2017

This paper presents a torque ripple reduction method of direct torque control (DTC) using fuzzy controller with optimal selection strategy of voltage vectors in a five-phase induction motor. The conventional DTC method has some drawbacks. First, switching frequency changes according to the hysteresis bands and motor's speed. Second, the torque ripple is rapidly increased in long control period. In order to solve these problems, some/most papers have proposed torque ripple reduction methods by using the optimal duty ratio of the non-zero voltage vector. However, these methods are complicated in accordance with the parameter. If this drawback is eliminated, the torque ripple can be reduced compared with conventional method. In addition, the DTC can be simply controlled without the use of the parameter. Therefore, the proposed algorithm is changing the voltage vector insertion time by using the designed fuzzy controller. Also, the optimized voltage vector selection method is used in accordance with the torque error. Simulation and experimental results show effectiveness of the proposed control algorithm.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.608-616
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• 2010

Seoul Metropolitan Rapid Transit Corporation, managing the line number 5,6,7 and 8 has inspected and maintained for the maintenance of the facilities spread in the extended 152km and 148 stations. Despite the thorough inspection for prevention of the facility failure, the failure has continuously occurred, due to the environmental factors of the underground, mechanical worn-out caused by frequent use, aging facilities, system error, negligence on use, etc. We have achieved a 53.4% reduction in the number of failure by the end of June, 2010 by breaking the conventional way of inspections and maintenance and by adopting quantitative goal management and new way of work. In this paper, we will analyze the problems of inspections and maintenance of the railway facilities, the failure reduction strategy and the performance of each strategy.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.560-563
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• 2000

In this paper we proposed AC/DC boost converter to improve input current harmonic reduction in TIG welder. The proposed harmonic reduction circuit with UC2854AN acting on constant switching frequency average current control has a three-loop control structure : the inner current loop the line voltage feed-forward loop and th outer voltage loop. Also we applied the constant current strategy on full bridge IGBT inverter to stabilized the output current using the analog PI controller. To demonstrate the practical significance of the proposed methods some simulation studies and experimental results are presented.

• Journal of Trauma and Injury
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• v.25 no.3
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• pp.91-93
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• 2012

Postraumatic lung hernia is a rare occurrence. A number of cases reported in the literature have been treated with early thoracotomy to repair partial protruded lung and pleura to prevent strangulation and incarceration. We present a case of a 45-year-old patient of left posttrumatic lung hernia, in which closed digital reduction was successful. The strategy of the management approach could be established by further accumulated experience.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.886-895
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• 2009

The guideline of selection of Integrated Management Practices (IMPs), such as wood, green roof, lawn, and porous pavement, for Low Impact Development (LID) design was proposed by ranking the reduction rate of surface runoff using LIDMOD1.0. Based on the guideline, LID was designed with several scenarios at two apartment complexes located at Songpa-gu, Seoul, Korea, and the effect of LID on surface runoff was evaluated during last 10 years. The effect of runoff reduction of IMP by land use change was highly dependent on the kind of hydrologic soil group. The wood planting is the best IMPs for reduction of surfac runoff for all hydrologic soil groups. Lawn planting is an excellent IMP for hydrologic soil group A, but reduction rate is low where soil doesn't effectively drains precipitation. The green roof shows constant reduction rate of surface runoff because it is not influenced by hydrologic soil group. Compared to the rate of other IMPs, the green roof is less effect the surface runoff reduction for hydrologic soil group A and is more effect for hydrologic soil group C and D followed to planing wood. The porous pavement for the impervious area is IMPs which is last selected for LID design because of the lowest reduction rate for all hydrologic soil group. As a result of LID application at study areas, we could conclude that the first step of the strategy of LID design at apartment complex is precuring pervious land as many area as possible, second step is selecting the kind of plant as more interception and evapotranspiration as possible, last step is replacing impervious land with porous pavement.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.11-26
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• 2018

A strategic technology selection for GHG reduction is crucial to secure mitigation means. Especially, a technology selection for a public sector is encouraged to consider integrated perspectives due to various stakeholders under public goals. However, previous studies have mainly focused on technological and economic factors, moreover, consistent criteria have not been applied. This study develops indicators for the GHG reduction technology selection from the public perspective based on delphi method with 22 experts. The result provides valid indicators of technology selection for GHG reduction considering an aspect of technology, economics, environment, policy, society. Specifically, 16 indicators from 5 categories on commercialized technology, and 18 indicators from 5 categories on new technology. We expect that those indicators are useful for a decision-making tool of technology selection. Moreover, provide the basis for the study of judgement criteria to evaluate GHG reduction technology.