• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1847-1850
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• 2008

The process conditions during ultraviolet nanoimprint lithography (UV-NIL) process such as temperature, stamping pressure, UV irradiation, etc. are effective factors for successful imprinting of complex and fine patterns. In this study, the effects of aluminum mold on the thermal characteristics of UV-NIL process were investigated through imprinting experiments and numerical simulations. The temperature of polymer resin on mold was measured to study thermal characteristics during UV curing. From the experimental and numerical results, the importance of curing reaction control for UV-NIL process was discussed for deformation characteristics.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2008.04a
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• pp.179-186
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• 2008

현재 대부분의 산업용 열기관은 효율을 높이기 위하여 연소에 사용되는 공기를 예열하는 방법을 사용한다. 하지만, 산업용 열기관에서 평균적으로 발생되는 $1000^{\circ}C$ 이상의 배기가스는 일반 금속 열교환기에는 적합하지 않다. 이에 반해 세라믹 열교환기의 경우 고온에서 견디는 장점이 있다. 본 연구에서는 기본적인 열교환기 설계 이론을 이용하여 설계프로그램을 제작하였다. 또한 세라믹 열교환기 내 열 유체 거동을 CFD 상용코드인 FlUENT 6.2를 이용한 전산해석을 수행하여 설계결과를 비교 검증하였다. 설계 결과에서 휜의 형태 변화에 따라 열전달율과 온도구배는 무시할 수 있을 정도로 작았으나, 압력강하는 크게 변동되는 결과가 도출되었다. 제한된 모듈 크기에서 휜 간거리는 휜의 두께에 비해 약 3배 이상 클 경우가 적당하며, 판(plate)의 두께는 작을수록 압력손실이 적고, 열전달율이 상승하지만 두께가 너무 얇게 된다면 제작상의 어려움이 생긴다. 향후 연구에서는 단순한 구조에서 벗어나 off-set이나 판형구조를 고려하여 설계함으로서 열전달 면적을 넓히거나 난류유동을 발생시켜 열전달율을 높이는 연구를 진행 할 필요가 있다.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1937-1941
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• 2007

During a process of a nanoimprint for manufacturing LCD, a small temperature variation on the LCD glass can cause thermal stress and generate unexpected displacement. To avoid this trouble, a precision temperature control unit using thermoelectric modules is appropriate for nanoimprint processes. The unit consists of an air control system, a cooling water control system, and a power control system. The air control system includes a thermoelectric module, thermocouples measuring temperatures of air and a duct-stale fin, and two air fans. The heat generated by the thermoelectric module is absorbed by the cooling water control system. The power control system catches the temperature of the thermoelectric module, and a PID controller with SCR controls the input power of the thermoelectric module. Temperature control performance is evaluated by experiment and simulation. The temperature control unit is able to control the exit temperature about ${\pm}2^{\circ}C$ from the incoming fluid temperature, and the error range is ${\pm}0.1^{\circ}C$. However, the control time is approximately 30minute, which needs further study of active control

• Korea Journal of Hospital Management
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• v.20 no.3
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• pp.64-73
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• 2015

Medical tourism in Korea has been rapidly grown for last couple of years, based on exclusive support from Korean government. About 60,000 foreign patients received medial services in 2009, an initial stage of entering medical tourism business, and the number of foreign patients received medical services in Korea hiked to more than 266 thousands in 2014, which is showing 34.7% of annual average increase between 2009 and 2014. Diversification of target markets and service areas contributed on this remarkable growth. This paper describes current status of medical tourism in Korea as well as various supports from government for the growth of medical tourism. In addition, the paper presents approaches for brand marketing, by utilizing 7Ps, the marketing mix (a.k.a. service mix), in order to increase awareness and competitiveness of medical services of Korea in global market.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2375-2380
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• 2008

Controlling of thermal environment and flow in nanoimprint process chamber is important to ensure high precision levels of products. The purpose of this paper is to build optimal nanoimprint process environment. Because of this, Optimum PI control parameter for precise temperature control has been examined. Also porous medium of ventilation system is simulated for uniform flow in the equipment chamber. The porous medium consists of mesh structure, and is installed to place which flow the influx of the air flows. PID control parameter is based on the data obtained by experiment. And then heating and cooling method which simultaneously operated was used for decreasing an error. In conclude temperature in the equipment chamber was able to control precisely in the range of ${\pm}0.1^{\circ}C$ by the PID control parameter and Deadband.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1543-1548
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• 2010

Powder metallurgy processes are used to form Net-Shape products and have been widely used in the production of automobile parts to improve its manufacture productivity. Powder-forging technology is being developed rapidly because of its economic merits and because of the possibility of reducing the weight of automobile parts by replacing steel parts with aluminum ones, in particular while manufacturing automotive parts. In the powder-forging process, the products manufactured by powder metallurgy are forged in order to remove any pores inside them. Powderforging technology can help expand the applications of powder metallurgy; this is possible because powder-forging technology enables the minimization of flashes, reduction of the number of stages, and possible grain refinement. At present, powder forging is widely used for manufacturing primary mechanical parts as in combination with the technology of powder forging of aluminum alloy pistons.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.207-216
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• 2005

Spawning behaviors of Squalidus gracilis majimae (Cyprinidae) were observed in the laboratory whose environmental factors such as light (D/L = 16 : 8), temperature ($20\;{\sim}\;24\;＾{\circ}C$), and dissolved oxygen (>8 mg $L^{-1}$) were quite regularly controlled. The behavioral patterns were categorized into three stages ofpre-spawning, spawning, and Post-spawning behaviors. In Particular, the pre-spawning stage was specified by 11 specific behavioral patterns of aggressive mating behaviors. During the spawning stage, the male and female performed four distinct spawning behaviors including sexual temptation, stimulation, egg spawning, and the separation, and randomly laid about 200 ${\sim}$ 300 eggs on the bottom substrates through the night. After finishing spawning, two adults separated toward their refuges and showed 3 types of post-spawning behaviors such as the resting, occasional eggs protecting, and the egg eating. The fish was identified as a partial-parental care species after the spawning.

• The Korean Journal of Financial Management
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• v.24 no.4
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• pp.45-73
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• 2007

The empirical results are summarized as follows : First, In relation to effects of ownership structure on firm value, there is the non-linear relationship between major(and foreign) shareholder's holdings and firm value. So the results(the compromise hypothesis) by prior researches(Morck et al. 1988 and so forth) is supported. However Institutional shareholder's holdings do not show the significant results. Second, In relation to effects of outside directors on firm value, equally the results of prior researches(Vafeas 2000, Choi et al. 2004), the higher the ratio of outside directors in the board, the higher firm value. Also there is the non-linear relationship between outside directors ratio and firm value. Furthermore, the higher the possibility of outside directors election in the board, the higher the relationship between ownership structure and firm value. As the economic importance of KOSDAQ is more increase, the researches of KOSDAQ should be more realized.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.157-167
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• 2016

Detached residential housing areas are located in the west part of Pangyo City. Seven areas of them are designated for the displaced residents from their original homes by the city development, in which commercial use on the first floor is permitted. The District Plan for the areas were establishes, and one of its main goals is to secure privately owned public spaces (POPS). This research conducted a post enumeration survey on the POPS on the blocks in the seven areas, which blocks contain inner corridors between two rows of housing units. Analytical review of the survey result reveals that (1) POPS facing roads are mainly being used as parking lots or expansion-spaces for the commercial use on the first floor, (2) inner POPS forming corridors are being neglected and otherwise being used as storage areas or outdoor sub-kitchen spaces, and (3) no consideration has been taken for the continuity of the sloped corridors. Regardless of a few good practices in terms of air circulation and lighting, the POPS in the blocks prove to be limited in following the plan's original design intentions and principles.

• The Korean Journal of Financial Management
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• v.24 no.2
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• pp.113-145
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• 2007

In this paper, we examine whether the poor performance of distressed firms where banks take equity may occur due to agency problems in banks. By adopting the debt-equity swap, the bank can effectively postpone the occurrence of bad loans form the failure of the distressed firm. As a result, firms with more debt will be more likely to obtain debt-equity swap, regardless of their probabilities of revival. This is not because they are more profitable, but because they have more debt and thus it poses greater risk to the bank. We empirically look into these predictions with the data of 44 workout firms and find the following results. First, debt-equity swap appears to be more applicable especially when the distressed firms are large and when BIS of related banks is low. Specifically, the conditional probability of 'large firms' based on debt-equity swap is 65.52% and the conditional probability of 'bad banks' based on debt-equity swap is 75.86%. Also, as predicted, the performance of these debt-equity firms is poorer than that of non debt-equity firms. The conditional probability of 'large firms' based on posterior failure is 84.62% and the conditional probability of 'bad banks' based on posterior failure is 84.62%. This is consistent with our predictions and is also confirmed through results of the logit regression analysis. Second, when the restructuring is led by 'good banks', the performance of equity-swap firms is superior to that of non equity-swap firms. This result is consistent with that of James(1995). Hence, we can conclude that there may be some agency problems in restructuring distressed firm-especially when distressed firms are large and banks are bad. And these agency problems can reconcile the difference between James' results and Park, Lee, and Jang's.