• International Journal of Control, Automation, and Systems
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• 제6권5호
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• pp.627-638
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• 2008

With the shift of the electric power industry from a regulated monopoly structure to a competitive market environment, the focus of the transmission expansion planning has been moving from reliability-driven transmission expansion to market-based transmission expansion. In market-based transmission expansion, however, a growing demand for electricity, an increasing number of transmission bottlenecks, and the falling levels of transmission investment have created the need for an incentive to motivate investors. The expectation of profit serves as a motivational factor for market participants to invest in transmission expansion in a competitive market. To promote investment in transmission expansion, there is an increasing need for a systematic method to examine transmission expansion for investment incentives from multiple perspectives. In this paper, the transmission expansion problem in a competitive market environment is formulated from ISO and investors' perspectives. The proposed method uses parametric analysis to analyze benefits for investors to identify the most profitable location and amount for transmission addition. Numerical results are presented to demonstrate the effectiveness of the proposed method.

• 한국멀티미디어학회논문지
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• 제14권12호
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• pp.1536-1543
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• 2011

Video stabilization is a very important step for vision based applications in the vehicular technology because the accuracy of these applications such as obstacle distance estimation, lane detection and tracking can be affected by bumpy roads and oscillation of vehicle. Conventional methods suffer from either the zooming effect which caused by a camera movement or some motion of surrounding vehicles. In order to overcome this problem, we propose a novel video stabilization method using FOE(Focus of Expansion). When a vehicle moves, optical flow diffuses from the FOE and the FOE is equal to an epipole. If a vehicle moves with vibration, the position of the epipole in the two consecutive frames is changed by oscillation of the vehicle. Therefore, we carry out video stabilization using motion vector estimated from the amount of change of the epipoles. Experiment results show that the proposed method is more efficient than conventional methods.

• 신재생에너지
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• 제3권4호
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• pp.22-30
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• 2007

An expansion device plays an important role in optimizing the heat pumps by controlling refrigerant flow and balancing the system pressures. Conventional expansion devices are being gradually replaced with electronic expansion valves due to increasing focus on comfort, energy conservation, and application of a variable speed compressor. In addition, the amount of refrigerant charge in a heat pump is another primary parameter influencing system performance. In this study, the flow characteristics of the expansion devices are analyzed, and the effects of refrigerant charge amount on the performance of the heat pump and the variation of compressor speed are investigated at various operating conditions. Mass flow rate through capillary tube, short tube orifice, and EEV was strongly dependent on the upstream pressure and subcooling. The heat pump system is very sensitive with a variation of refrigerant charge amount. The performance of it can be optimized by adjusting the flow rate through expansion device to maintain a constant superheat at all test conditions.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.538-541
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• 2007

An expansion device plays an important role in optimizing the heat pumps by controlling refrigerant flow and balancing the system pressures. Conventional expansion devices are being gradually replaced with electronic expansion valves due to increasing focus on comfort, energy conservation, and application of a variable speed compressor. In addition, the amount of refrigerant charge in a heat pump is another primary parameter influencing system performance. In this study, the flow characteristics of the expansion devices are analyzed, and the effects of refrigerant charge amount on the performance of the heat pump are investigated at various operating conditions. Cooling capacity of the heat pump system is strongly dependent on load conditions. The heat pump system is very sensitive with a variation of refrigerant charge amount. But, the performance of it can be optimized by adjusting the flow rate through expansion device to maintain a constant superheat at all test conditions.

• 말소리와 음성과학
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• 제11권2호
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• pp.15-21
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• 2019

Korean and English are both known to show on-focus pitch range expansion and post-focus pitch range compression (PFC). But it is not clear if this prosodic similarity would make it easy for Korean speakers to learn English focus prosody. In the present study, we conducted a production experiment using phone number strings to examine whether Korean learners of English produce a native-like focus prosody. Korean learners of English were classified into three groups (advanced, intermediate and low) according to their English proficiency and were compared to native speakers. Results show that intermediate and low groups of speakers did not increase duration, intensity, and pitch in the focus positions, nor did they compress those cues in the post-focus positions. Advanced speakers noticeably increased the acoustic cues in the focus positions to a similar extent as native speakers. However, their performance in post-focus positions was quite far from that of native speakers in terms of pitch and excursion size. These results thus demonstrate a lack of positive transfer of focus prosody from Korean to English in L2 learning, and learners may have to relearn it from scratch, which is consistent with a previous finding. More importantly, the results provide further support for the view proposed in other works that acoustic properties of PFC were not easily transferred from one language to another.

• Kyungpook Mathematical Journal
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• 제57권3호
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• pp.371-383
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• 2017

Let M be a matroid. We study the expansions of M mainly to see how the combinatorial properties of M and its expansions are related to each other. It is shown that M is a graphic, binary or a transversal matroid if and only if an arbitrary expansion of M has the same property. Then we introduce a new functor, called contraction, which acts in contrast to expansion functor. As a main result of paper, we prove that a matroid M satisfies White's conjecture if and only if an arbitrary expansion of M does. It follows that it suffices to focus on the contraction of a given matroid for checking whether the matroid satisfies White's conjecture. Finally, some classes of matroids satisfying White's conjecture are presented.

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2008년도 춘계학술대회
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• pp.957-962
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• 2008

We propose a model for the line expansion problem in the AMOLED (Active Matrix Organic Light Emitting Diodes) industry, which now faces market uncertainty: for example, changing customer needs, technological development path, etc. We focus on the optimal investment time and size of the AMOLED production lines. In particular, employed here is the ROV (Real Options Valuation) model to show how to capture the value of line expansion and to determine the optimal investment time. The ROV framework provides a systematic procedure to quantify an expected outcome of a flexible decision which is not possible in the frame of the traditional NPV (Net Present Value) approach. Furthermore, we also use Monte Carlo simulation to measure the uncertainty associated with the line expansion decision; Monte Carlo simulation estimates the volatility of a decision alternative. Lastly, we present a scenario planning to be conducted for what-if analysis of the ROV model.

• 산업경영시스템학회지
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• 제43권3호
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• pp.29-40
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• 2020

Korean firms have been vigorously searching and exploring overseas market opportunities through export and overseas investment. As of end of 2019, there were more than 80,000 Korean overseas subsidiaries all over the world. With Korean overseas direct investment increasing recently, it became one of the important issues for overseas investors to be successful in the global market. There are a lot of studies on factors influencing the performance of overseas subsidiaries such as 'firm' and 'country' factors. This study empirically examines subsidiary performance determinants with 'industry architectures' by using a sample of 292 overseas Korean firm subsidiaries. Industry architectures are the stable but evolving sets of rules and roles through which labor is divided within a sector. This article considers how industry architectures shape success in international expansion. Industry architectures differ between countries, are not necessarily technologically determined, shape firms' capabilities and their competitive environment, and constitute a distinct level of analysis. We extract antecedents of related theory and empirically test its impact with a survey of Korean firms expanding in emerging economies. We would say this is the first study which tries to focus on industry architectures with the performance of Korean overseas subsidiaries. We find that separability and similarity of industry architectures across countries and localization of subsidiaries are robust and important predictors of success in international expansion. Our results suggest that industry architectures should be added to firm and country as an intermediate level of analysis that helps explain success in international expansion. While we established a pattern, much more remains to be done. We focus on the success of foreign operations, but we do not consider the broader benefits of going abroad, such as the learning or network effects that accrue at the level of the entire firm. The next obvious question is whether the results would differ in the developed market context. These we leave for future research to consider.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.34.1-34
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• 2002

1. Introduction 2. Focus of Expansion 3. Log-Polar Mapping 4. Egomotion and Optical Flow 5. Experimental Results 6. Conclusion. References.

• 설비공학논문집
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• 제15권8호
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• pp.661-666
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• 2003

Constant area expansion devices such as capillary tubes, short tube orifices are being gradually replaced with electronic expansion valves (EEVs) because of increasing focus on comfort and energy conservation. In this study, the performance of a water-to-water heat pump as a function of refrigerant charge is investigated in steady state, cooling mode operation with expansion devices of a capillary tube and an EEV. The performance of the capillary tube system varies drastically according to the change of refrigerant charge amount and inlet temperature of the secondary fluid in the condenser. Cooling capacity and COP of the EEV system show little dependence on the refrigerant charge, while those are strongly dependent on the secondary fluid temperature at the condenser inlet. In general, for a wide range of operating conditions the EEV system shows much higher performance as compared with the capillary tube system. The performance of the EEV system can be optimized by adjusting EEV opening to maintain a constant superheat at all test conditions.