• Journal of Magnetics
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• v.16 no.1
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• pp.58-63
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• 2011

This paper presents design procedures of a transverse flux linear motor (TFLM). The minimum and maximum flux linkage was determined by the simplified equivalent magnetic circuit and estimated average magnetic flux density at the air gap region by considering the shape of applied magnetomotive force (MMF). With this information, the number of turns of each phase winding was calculated based on the amplitude of applied voltage and speed of a mover. The rated current, coil diameter, and winding area were obtained with the aid of an empirical formula for determining the required MMF. The usefulness of the proposed design method for TFLM is verified by the three-dimensional equivalent magnetic circuit network (EMCN) method and the experimental results of prototyped machine.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1371-1372
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• 2012

협업 필터링은 유사한 사용자를 선별하여 아이템을 추천하는 대표적인 추천 방법이다. 협업 필터링을 이용한 추천에서 추천 품질은 유사 사용자를 선별하는 기법에 따라 크게 달라질 수 있다. 본 논문에서는 협업 필터링 추천의 품질을 크게 개선 시킬 수 있는 새로운 유사 사용자 선별 기법을 제안한다. 제안하는 기법에서는 Earth Mover's Distance (EMD)를 이용하여 사용자간의 유사도를 정의한다. EMD를 적용하기 위해서 각 사용자를 히스토그램으로 표현하며, 히스토그램 빈(bin)간의 거리를 정의한다. 이렇게 정의된 유사도를 이용하여 타깃 사용자와 유사한 사용자들을 선별하며, 이를 기반으로 타깃 사용자가 부여한 타깃 아이템에 대한 점수를 예측한다. 다양한 실험을 통하여, 제안된 기법이 기존 기법들과 비교하여 추천의 정확도를 최대 30%까지 향상시키는 것으로 나타났다.

• Asia Marketing Journal
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• v.19 no.4
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• pp.37-59
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• 2018

This study investigates the effects of the distribution channel structure on quality decisions under duopoly competition. I considers a set-up in which two retailers compete on product quality and retail price. In the set-up, the integrated retailer has the power to determine the quality of its exclusive product, while the decentralized retailer does not. For the decentralized retailer, the supplier determines product quality. I find that asymmetric pairs of a decentralized channel by one retailer and an integrated channel by the other retailer can be a Nash equilibrium in a simultaneous-channel-choice model. The two retailers select different levels of quality, and this quality competition benefits retailers by softening price competition. In a sequential-channel-choice model, I find that the leader can obtain a first-mover advantage. From the perspective of the supplier, which can decide the distribution channel structure and level of quality, both suppliers choose the decentralized channel in equilibrium.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.172-174
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• 2020

기존의 절대위치 감지 방식은 초기위치를 알기 위하여 이동자의 위치를 초기화해야 하고 생산 단가가 높다는 단점을 보완하기 위해 MR 센서를 이용하여 비접촉 방식으로 선형모터 이동자 절대위치를 판별하는 시스템을 제안하였다. 센서값을 이용하여 절대위치를 판별해야 하기 때문에 ADC 기능과 실시간 연산 기능이 필요하다. 때문에 8bit MCU(Atmega324PA)를 이용했다. 본 논문에서 이용한 MR 센서의 출력 변동폭이 작기 때문에 Instrumentation Amplifier를 이용하여 증폭된 출력을 MCU로 읽어 사용했다. 제안 시스템의 회로 및 알고리즘을 구현하였고 이를 이론적, 실험적 분석을 통해 동작 및 타당성을 검증하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.585-594
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• 2013

In this study, laboratory experiments and numerical simulations were conducted to test the performance of resonance power buoy system proposed by Kweon et al.(2010). The system is composed of a linear generator and a mooring buoy. The mover of the linear generator mainly has heave motion driven by vertical oscillation of the buoy. In this system, the velocity discrepancy between the mover and the buoy makes electricity. However, ocean wave energy as a natural resource around Korean peninsula is comparatively small and the driving force for producing electricity is not enough for commercialization. Therefore, it is necessary that the buoy motion be amplified by using resonance characteristics. In order to verify the resonance effects on the test power buoy, the experimental investigations were conducted in the large wave flume (length of 110 m, width of 8 m, maximum depth of 6 m) equipped with regular and random plunger wave generator. The resonance draft of test power buoy is designed for the corresponding period of incident wave, 1.96 sec. Regular wave test results show that the heave response amplitude operator(RAO) by a test buoy has the amplification of 5.66 times higher compared to the wave amplitude at the resonance period. Test results of random waves show that the buoy has the largest spectrum area of 20.73 times higher at the point of not the resonance period but the shorter one of 1.85 sec. Therefore this study suggests the resonance power buoy for wave power generation for commercial application in the case of the coastal and oceanic area with smaller wave energy.

• Journal of Arbitration Studies
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• v.28 no.4
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• pp.3-42
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• 2018

This paper aims to explore ways to develop the arbitration industry in Korea. The prospects for the promotion of the arbitration industry in Korea are never dim. International arbitration competitiveness is somewhat lower than its competitors at present, but the international economic base to support it is solid, and the domestic arbitration environment seems to be sufficient to support the development possibility of arbitration. Since geographical and economic factors have already been defined, Korea must at least improve the arbitration act with passion and vision for the best one. The arbitration act that is the most accessible to arbitration consumers is the best arbitration act. The important thing is to have an arbitration act that makes people want to use more than litigation or other dispute resolution procedures. There is no hope of remaining as a "second mover" in the field of arbitration law. One should have a will and ambition to become a "first mover" even if it is risky. Considering the situation of the current arbitration law, it is necessary to start an arbitration appeal system in order to become a consumer-friendly arbitration law, and it is necessary to examine ways of integrating the grant of execution clause and enforcement application procedures. The abolition of the condition of Article 35 of the Arbitration Act, which rules the validity of the arbitration award, will help promote international arbitration. Exclusion agreements of setting aside against arbitration awards must also be fully recognized. It is also important to publish a widely cited international arbitration journal. In order to respond to the fourth industrial revolution era, it is necessary to support the establishment of a dispute resolution system that utilizes IT technology. In order to actively engage the arbitrators in the market, it is necessary to abolish the regulations that exist in the Attorneys-at-Law Act. There is also a need to allocate more budget to educate arbitration consumers and to establish arbitration training centers to strengthen domestic arbitration education. It is also necessary to evaluate and verify the Arbitration Promotion Act so that it can achieve results. In the international arbitration market, competition is fierce and competitors are already taking the initiative, so in order not to miss the timing, Korea needs to activate international arbitration first. In order to activate international arbitration, the arbitration body needs to be managed with the same mobility and strategy as the agency in the marketplace. In Korea, unlike in Singapore and Hong Kong, it is necessary to recognize that the size of the domestic arbitration market is very likely to increase sharply due to the economic size of the country and the large market potential it can bring from litigation. In order to promote the arbitration industry, what is most important is to make arbitration activities in accordance with the principles of the market and to establish an institutional basis to enable competition. It is urgently required to change the perception of the relevant government departments and arbitration officials.

• Analyses & Alternatives
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• v.7 no.2
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• pp.35-77
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• 2023

This study aims to solve the entangled loop between demographic transition (DT) and economic growth by analyzing cross-country data. We undertake a national-level group analysis to verify the compressed transition of demographic variables over time. Assuming that the LA (latecomer advantage) on DT over time exists, we verify that the DT of the latecomer is compressed by providing a formal proof of LA on DT over income. As a DT has the double-kinked functions of income, we check them in multiple aspects: early maturation, leftward threshold, and steeper descent under a contour map and econometric methods. We find that the developing countries (the latecomer) have speedy DT (CDT, compressed DT) as well as speedy income such that DT of the latecomers starts at lower levels of income, lasts for a shorter period, and finishes at the earlier stage of economic development compared to that of developed countries (the early mover). To check the balance of DT, we classify countries into four groups of DT---balanced, slow, unilateral, and rapid transition countries. We identify that the main causes of rapid transition are due to the strong family planning programs of the government. Finally, we check the effect of latecomer's CDT on economic growth inversely: we undertake the simulation of the CDT effect on economic growth and the aging process for the latecomer. A worrying result is that the CDT of the latecomer shows a sharp upturn of the working-age population, followed by a sharp downturn in a short period. Compared to early-mover countries, the latecomer countries cannot buy more time to accommodate the workable population for the period of demographic bonus and prepare their aging societies for demographic onus. Thus, we conclude that CDT is not necessarily advantageous to developing countries. These outcomes of the latecomer's CDT can be re-interpreted as follows. Developing countries need power sources to pump up economic development, such as the following production factors: labor, physical and financial capital, and economic systems. As for labor, the properties of early maturation and leftward thresholds on DTs of the latecomer mean that demographic movement occurs at an unusually early stage of economic development; this is similar to a plane that leaks fuel before or just before take-off, with the result that it no longer flies higher or farther. What is worse, the property of steeper descent represents the falling speed of a plane so that it cannot be sustained at higher levels, and then plummets to all-time lows.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.558-563
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• 2012

In this paper, a novel planar type magnetic levitation system without other assistant devices is proposed and it can move with 6 degree of freedom (X, Y, Z, ${\theta}_X$, ${\theta}_Y$, ${\theta}_Z$) in wafer size as well as in nano scale positioning.The mover is composed with 2-D Halbach permanent magnet array and the stator is composed with $10{\times}10$ coil arrays.It was composed in laboratory and tested with short stroke (4 [mm]) and long stroke (160 [mm])movements. The errors of short movement test is [X, Y, Z, ${\theta}_X$, ${\theta}_Y$, ${\theta}_Z$]${\leq}$ [${\pm}200nm$, ${\pm}200nm$, ${\pm}250nm$, ${\pm}3urad$, ${\pm}2urad$, ${\pm}1urad$]The errors of long stroke movement test is [X, Y, Z, ${\theta}_X$, ${\theta}_Y$, ${\theta}_Z$]${\leq}$ [${\pm}200nm$, ${\pm}200nm$, ${\pm}250nm$, ${\pm}1.5urad$, ${\pm}2urad$, ${\pm}0.5urad$].

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1675-1680
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• 2011

Inductive power transfer module(IPTM) is a contact-less power supply device and its application range has been extended to the large capacity devices such as electric vehicles, industrial mover and railway system as well as small capacity devices such as electric toothbrush charger, celluar phone charger, and so on. For railway application, the IPTM will transfer energy while train stops at a station for around 30[sec]. Therefore, equivalent circuit parameters and coupling coefficient of IPTM are an important design factor for the high energy transfer efficiency. This paper investigates the properties of equivalent circuit parameters and coupling coefficient of U-U type IPTM and U-I type IPTM using an analytical method and experimental method. Considering the coupling coefficient of the U-U type is larger than U-I type's, the U-U type is suitable for an application which need maximum power transfer and high efficiency.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3079-3085
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• 2011

Through Korean Urban Maglev Program started in 2006, an urban maglev train was developed and the demonstration line is under construction as of now in 2011. The target speed of the developed maglev train is 110km/h, and the core technologies for super speed maglev trains over 500km/h are being studied. The propulsion and levitation systems of the super speed maglev train under consideration consist of linear synchronous motors (LSM) and levitation electromagnets which also act as a mover of LSM. In addition, guidance electromagnets are used to ensure stable running on curved tracks during super speed operation. The levitation and guidance control is focused on in this paper. For experimental purpose, a small maglev train is being manufactured, and its levitation and guidance controller is studied. The main task of the controller is to maintain the gap between the corresponding electromagnet and the guideway constantly. In general, measurements of the gap, acceleration and current and so on are utilized, and the gap control is implemented independently for each electromagnet. In this paper, the levitation and guidance system is modelled considering mechanical interactions, and the levitation and guidance controller is proposed based on this model. The developed controller is verified by various simulations using MATLAB/Simulink.