• Journal of Information Technology Applications and Management
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• 제21권3호
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• pp.135-156
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• 2014

The Online business model for purchasing agent service is getting more popular. However, consumers perceive more risk when buying products from foreign online purchasing agents (FOPA) than from common online sellers (COS). This study focuses on finding out how consumers manage risk when they perceive risk and what different risk-reliever strategies they use when buying from high-risk FOPA and low-risk COS. This study has proved the following two. First, when consumers perceive risk at online purchasing, they tend to select risk-reliever strategies, such as the use of communication media, online assurance mark, seller's record, and secure payment to mitigate risk. With the application of those risk-reliever strategies, they built trust with the seller. Second, risk-perception of FOPA influences usage of communication media and check of online assurance mark more strongly than that of COS. On the contrary, risk-perception of COS influences the check of seller record more strongly than that of FOPA. This study helps to explain why FOPA is proliferating, despite its inherent high risk due to the fact that buyers and sellers are separated in time and space and that buyers and sellers have different social and cultural backgrounds. This study also helps managers of E-commerce to relieve consumer's risk-perception and to build trust.

• 전기학회논문지
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• 제65권3호
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• pp.493-498
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• 2016

Heart Rate Variability (HRV) represents beat-to-beat fluctuations of R-R intervals in Electrocardiogram (ECG). On of the clinical applications of HRV is to assess the mental-stress state by evaluating its power spectral density distribution. This study aims at finding new discriminative role of the coupled-oscillating coupling constants, Cs and Cp in the Integral Pulse Frequency Modulation (IPFM) model. Based on comparing with power spectral density of HRV in terms of the relative ratio of the low and high-frequency power component, we can conclude the fact that the coupling parameters Cs and Cp can replace the role of HRV power spectrum interpretation for judging the mental-stress state.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2536-2539
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• 2008

A study has been made on how to occur inertial oscillations in a rotating flow. The flow is considered to be induced by differentially-rotating top and bottom disks with infinite radius. The top and bottom disks are assumed to be set in motion over a finite initial start-up time duration from initial solid body rotation ($\Omega$) to each finial state, i.e., the top disk is rotating at the angular velocity (${\Omega}+{\Delta}{\Omega}$) and the bottom disk (${\Omega}-{\Delta}{\Omega}$). The system Reynolds number, which is a reciprocal of conventional Ekman number in rotating flows, is very high so that a boundary layer flow near disks is pronounced. From a strict theoretical analysis, it is clearly found the fact that inertial oscillation in a rotating flow is caused by excessive input of torque during start-up phase. Above finding comes from the following physics of theoretical result: in the case of abrupt start-up within very shorter time-duration than spin-up time scale, the inertial oscillation is magnified but it could be completely depressed in the case of mildly accelerated start-up, i.e., start-up process being established over diffusion time scale.

• 산업경영시스템학회지
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• 제37권1호
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• pp.50-59
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• 2014

In this paper, we develop an efficient approach to solve a multiple-item budget-constraint newsboy problem with a reservation policy. A conventional approach for solving such problem utilizes an approximation for the evaluation of an inverse of a Gaussian cumulative density function when the argument of the function is small, and a heuristic method for finding an optimal Lagrangian multiplier. In contrast to the conventional approach, this paper proposes more accurate method of evaluating the function by using the normalization and an effective numerical integration method. We also propose an efficient way to find an optimal Lagrangian multiplier by proving that the equation for the budget-constraint is in fact a monotonically increasing function in the Lagrangian multiplier. Numerical examples are tested to show the performance of the proposed approach with emphases on the behaviors of the inverse of a Gaussian cumulative density function and the Lagrangian multiplier. By using sensitivity analysis of different budget constraints, we show that the reservation policy indeed provides greater expected profit than the classical model of not having the reservation policy.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.388-393
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• 2009

It is important to know character about efficiency of converters before manufacturing it. Recently, various techniques are developed for solar array system. Converters can be used for control of solar array's condition. So, solar array with converter structures are very useful. If we want to measure converter's efficiency after manufacturing it. It's not difficult if we have measuring equipment. But we need to measure efficiency before realization converters for development of optimized efficiency and simulations. This research offers an efficiency calculation of single phase hard switching boost converter. And it is the most basic type of converters. In fact, it can be used techniques for getting higher efficiency like soft-switching and more. But the cost is an important issue in compact solar array system. One way to escape from the cost problem is finding optimized efficiency of basic types of convener.

• 대한기계학회논문집
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• 제13권3호
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• pp.500-507
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• 1989

본 논문에서는 흡배기 변동압을 실측하여 이것을 계산의 입력수치로 사용 하는 전산프로그램을 개발하여 간단하면서도 정확한 사이클 시뮬레이션이 가능하도록 하여 체적효율을 예측하였다.

• 한국항공운항학회지
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• 제23권3호
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• pp.42-52
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• 2015

Since the tax-free system for overseas laborers was implemented in 1974, the tax-free limits of international air crew, overseas construction workers and crewmen of deep-sea fishing ships and ocean-going ships had been identical by 2005, but there are big differences, currently. The Ministry of Strategy and Finance pointed out the poor working environments and international competitiveness of the industries to explain the reason for the differential tax-free limit. From this perspective, the fairness of the tax-free system for overseas laborers was analyzed. This is an empirical study, based on the objective fact. The study finding showed that international air crew were working in the structural flight work environments to threaten the right of health due to jet lag and excessive exposure to high-altitude cosmic radiation. Therefore, it was analyzed there should be a proper system reform to apply the tax-free limits to international air crew which are identical to those applied to overseas construction workers and crewmen of deep-sea fishing ships and ocean-going ships, for a fair taxation.

• 한국전자통신학회논문지
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• 제6권3호
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• pp.363-369
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• 2011

본 논문은 기술발전에 따라 등장하게 된 융합미디어에 대한 수용자 인지가 실제 이용 의도에 어떠한 영향을 미치는지 분석하였다. 분석결과, 융합미디어에 대한 인지된 유용성이 높다고 생각할수록 이용의도가 높아지며, 인지된 용이성이 높을수록 이용의도 역시 높아지는 것으로 나타났다. 이용 의도는 실제 이용도에 유의미한 영향을 미치는 것으로 나타났는데, 이용의도가 높을수록 융합미디어를 많이 이용한다는 것을 의미한다. 반면 혁신저항이 높을수록 인지된 유용성, 사용의도, 매체 친밀도는 낮아는 것으로 나타났다. 결국 혁신저항으로 인해 매체 이용의도가 낮아지고, 융합 미디어 수용이 지연되는 결과를 가져올 수 있다.

• 한국게임학회 논문지
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• 제11권5호
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• pp.23-30
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• 2011

무리 짓기는 대규모 무리의 사실적인 시뮬레이션으로 게임이나 컴퓨터 그래픽에서 자주 사용된다. 이러한 대규모 무리의 실시간 시뮬레이션은 계산 집약적 작업이기 때문에 효율적인 알고리즘에 대한 많은 연구들이 있었다. 본 논문에서는 기존의 효율적인 무리 짓기 알고리즘이 불필요한 계산을 포함하고 있다는 사실은 실험적으로 찾아내고, 간단한 휴리스틱으로 이러한 단점을 개선하는 새로운 알고리즘을 제안한다. 제안된 방법의 성능을 평가하기 위하여 많은 실험을 수행하였다. 실험의 결과는 제안하는 알고리즘이 기존의 효율적인 알고리즘에 비하여 평균 약 21%정도 성능을 개선한다는 것을 보였다.

• 한국디지털건축인테리어학회논문집
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• 제3권2호
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• pp.30-38
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• 2003

The purpose of this study was to analyze the demand estimation erection of lifetime sports facilities for making an accurate estimate of its demand on the basis of the rate of the people participating in lifetime sports activities. Participation rate was determined on the basis of the fact-finding survey [by the Ministry of Culture and Tourism(2000)] as a basis research on facilities demand, and its demand was calculated by making an estimate of facilities demand. An estimate of facilities demand was made in the equation by participation population, facilities demand for each person, sports space area for each person, time of sports, cycle of sports, possible time to use of sports space. Facilities demand for each person by sports event is the following: $swimming;0.03m^2$, $basketball;0.045m^2$, martial arts(taekwondo, judo, korean fencing);0.003 $75m^2$, $aerobics;0.0289m^2,\;health;0.00326m^2,\;badminton;0.00323m^2,\;tennis;0.01429m^2,\;soccer;0.1112m^2,\;squash;0.01323m^2$.