• 융복합기술연구소 논문집
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• 제2권1호
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• pp.38-42
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• 2012

A scroll compressor used in the air conditioning in automobile consists of the fixed scroll and the orbiting scroll. Temperature gradient in the scroll compressor during the operation induces the thermal expansion of two scrolls. Therefore, the gap between scrolls in the initial stage is regarded as an important variable in structural design of the scroll compressor. The coupled thermal-stress analysis was carried out for the scrolls of a scroll compressor. The temperatures of major points of two scrolls in the steady states were referred by the literature of C. Lin. The sequentially coupled thermal-stress analysis is utilized to the heat transfer analysis and the thermal expansion analysis. In the thermal expansion analysis, the contact analysis was considered between the fixed and the orbiting scrolls in order to obtain the penetration distance and the contact pressure between two scrolls. The range of deformation was from 44 to $76{\mu}m$ according to the height of the scroll. The maximum penetration distance of $60{\mu}m$ occurred at the top surface of the fixed scroll in the center of the scroll parts.

• Asian Journal of Innovation and Policy
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• 제4권1호
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• pp.103-127
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• 2015

This paper investigates the two academic revolutions of the Korean higher education system. Since economic catch-up began in the 1960s, Korea has strongly encouraged the activities of its higher education system to serve industrial development as it has progressed through various developmental stages. At the 'strong regulation' stage, universities focused on the provision of technicians. As the need for higher education grew, the 'massive expansion' stage emerged. Finally, most recently, university research and its direct contribution to the economy have been invigorated by strong governmental support. Possibly, this is due to the fact that the Korean government has strongly controlled not only industry but also academia. As long as other East Asian universities have similar conditions to those of the development of Korean universities, we can generalise this model not only to universities in other East Asian countries, but also to universities in other rapid catch-up countries.

• 한국산학기술학회논문지
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• 제12권2호
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• pp.1013-1019
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• 2011

본 논문에서는 천연가스를 액화시키기 위해서 프로판, 에틸렌 및 메탄 냉매를 이용한 다단 캐스케이드 냉동사이클에 대한 전산모사를 PRO/II with PROVISION 8.3에 내장되어 있는 Peng-Robinson 상태방정식을 활용하여 수행하였다. 천연가스의 조성은 한국가스공사로부터 제공받은 것을 적용하였으며, 유량은 연간 500만톤으로 가정하였다. 프로판 냉매의 공급온도는 $-40^{\circ}C$로, 에틸렌 냉매의 공급온도는 $-95^{\circ}C$로 메탄 냉매의 공급온도는 $-155^{\circ}C$로 각각 정하였으며, 천연가스와 각각의 냉매의 최소 접근온도는 $3^{\circ}C$로 정하였다. 다단 냉동을 위한 프로판 냉동 사이클은 3단 냉동을 가정하였으며, 에틸렌 냉동 사이클은 2단 냉동을 그리고 메탄 냉동 사이클은 3단 냉동을 가정하였다. 메탄 냉매에 의해서 $-152^{\circ}C$까지 냉각된 천연가스는 줄-톰슨 팽창에 의해서 $-162^{\circ}C$까지 냉각되어 액화가 일어나도록 하였다. 결론적으로 캐스케이드 냉동 사이클과 줄-톰슨 팽창을 통한 천연가스의 액화율은 몰 비로 91.71%이며, 액화천연가스 1.0 kg/hr당 0.433 kW의 압축 일이 필요함을 알 수 있었다.

• 통상정보연구
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• 제7권4호
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• pp.387-407
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• 2005

This paper is to study globalization motives and strategies of Japanese and Korean industries by analyzing the causes and patterns of foreign direct investment (FDI) of the firms of the two countries during the 1980s and 1990s. First we develop a FDI function from the profit maximizing model of firms. Then we use regression analysis to determine internally driving-out factors and externally-inducing factors. Japanese FDI strategy has gone through three different stages; from natural resource-seeking investment in the 1950s and 1960s to market-expansion investment in the 1970s and 1980s and to a combination of cost-reducing (low-cost labor-seeking) investment and market-penetrating investment in the 1990s. On the other hand, Korean FDI behavior has gone through four different stages; from the learning stage with small investments in the 1970s, to natural resource-seeking investment in the early and mid 1980s, to the growth stage in the late 1980s and the early 1990s, to the maturity stage of the mid and late 1990s. The last two stages were characterized by a combination of cost-reducing investment and market-seeking investment. As a late comer, Korea began its FDI two decades later than Japan, but caught up the patterns of Japanese FDI by the mid 1990s and is in a competing position with Japan. Our findings show that both Japanese FDI and Korean FDI in Asia and other developing countries tendto be in labor-intensive sectors where their firms are losing their comparative advantages at home. The main motive for FDI into these regions is low-cost resource seeking. On the other hand, both Japanese FDI and Korean FDI in the U.S. and Europe tend to be knowledge-intensive sectors where Japanese and Korean firms attempt to internalize transaction and information costs by globalizing its production. The main motive for FDI into these regions is market-seeking. Firms in both countries have increased their investments in Mexico and Western and Eastern Europe in order to penetrate large economic blocs such as the EU and NAFTA area. Korean firms are more aggressive in expanding into new and untested markets than are their counterpart in Japan. Evidence of this can be seen in the scarcity of Japanese FDI and abundance of Korean FDI in Eastern Europe and China.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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• pp.466-473
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• 1998

LRV(Light Rail Vehicle) is one of the most useful way for urban transit. HDPIC has designed and manufactured the LRV train set for Manila Line 1 expansion. The LRV is composed of two carbody sections which are coupled by a articulated bogie. The articulated bogie and two motorized bogies have slewing rings in order to improve the curving performance and ride quality. Carbody structures are mainly made of low-carbon stainless steel (STS301L), and the carbody bolsters and draft sills are made of rolled steel for welded structures. The authority's specifications specified the design load conditions and weight limits. Design load conditions are vertical load, compressive load and diagonal jacking, and the maximum axle load is 10.7 ton. In order to meet those requirements, the stiffness and strength of carbody structure were predicted using finite element analysis during design stage. The half or full structure is modeled and analyzed with design load conditions, and critical areas are analysed in detail using sub-modeling method. The strength and strength of carbody structure was also verified by the load test. The analysis and test results show a good agreement.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.599-606
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• 2000

본 연구는 피에조콘(Piezocone) 관입 시험에 의한 과잉간극수압의 소산(Dissipation)특성을 파악하기 위하여, 실측된 소산실험 결과치와 Gupta & Davidson에 의해 개발된 연속 공동확장이론(Successive Cavity Expansion Theory) 모델을 비교하였고, 그 경험적 이론의 적합성을 규명하였다. 연속 공동확장 이론이란, 콘 관입이 유발하는 관입 주변지반의 변환 메커니즘을 연속적인 공동확장의 전개과정로 파악할 때, 관입주변의 연속적 공동확장 영역에서 발생된 과잉간극수압들은 연속적으로 소산되어지고, 결국에는 관입멈춤직후 얻게 되는 소산시험의 결과도 이러한 과잉간극수압의 연속적 소산 메커니즘으로부터 그 영향을 받는다는 개념이다. 본 연구의 실험방법은 Piezocone 관입을 위한 연약모형지반 조성을 위하여 초대형 Slurry Consolidometer에 Slurry를 45일간 압밀시킨후 Calibration Chamber(Louisiana State University Calibration Chamber System)에 옮긴 후 2차 압밀시키는 Two-Stage Consolidation Method를 사용하였다. 또한 모형지반내에 8개의 Piezometers를 설치하여 Piezometers를 설치하여 Piezocone 관입시 유발되는 지반 내에서의 과잉간극수압의 변환을 측정하였다. 실험결과와 이론 예측치를 비교함으로써 연속 공동확장이론 모델은 u$_2$형식의 피에조콘 관입 소산시험 결과들과 잘 들어맞는 모습을 보여줬으나, 관입으로 인한 주변 지반의 과잉간극수압의 소산변화는 정성적으로만 모사 되는 모습을 보여줬다.

• 산경연구논집
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• 제11권3호
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• pp.7-17
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• 2020

Purpose: This study reexamines the test on the pricing of accruals quality. Theory suggests that information risk is a priced risk factor. Using accruals quality as the proxy for information risk, researchers have tested the pricing of information risk. The results are inconsistent potentially because of the information shock in the realized returns that are used as the proxy for expected returns. Based on this argument, this study revisits this issue excluding information-shock-free measure of expected returns. Research design, data and methodology: This study estimates expected returns using the vector autoregression model. This method extracts information shocks more thoroughly than the methods in prior studies; therefore, the concern regarding information shock is minimized. As risk premiums are larger in recession periods than in expansion periods, recession and expansion subsamples were used to confirm the robustness of the main findings. For the pricing test, this study uses two-stage cross-sectional regression. Results: Empirical results find evidence that accruals quality is a priced risk factor. Furthermore, this study finds that the pricing of accruals quality is observed only in recession periods. Conclusions: This study supports the argument that accruals quality, as well as the pricing of information risk, is a priced risk factor.

• Radiation Oncology Journal
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• 제16권4호
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• pp.357-366
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• 1998

Brachytherapy is an essential part of radiotherapy for uterine cervical cancer. The low dose rate (LDR) regimen has been the major technique of intracavitary therapy for cervical cancer. However, there has been an expansion in the last 20 years of high dose rate (HDR) machines using Ir-192 sources. Since 1979, HDR brachytherapy has been used for the treatment of uterine cervical cancer in Korea. The number of institutions employing HDR has been increasing, while the number of low dose rate system has been constant. In 1995, there was a total 27 HDR brachytherapy units installed and 1258 cases of patients with cervical cancer were treated with HDR Most common regimens of HDR brachytherapy are total dose of 30-39 Gy at point A with 10-13 fractions in three fractions per week. 24-32 Gy with 6-8 fractions in two fractions per week, and 30-35 Gy with 6-7 fractions in two fractions per week. The average fractionation regimen of HDR brachytherapy is about 8 fractions of 4.1 Gy each to Point A. In Korea, treatment results for HDR brachytherapy are comparable with the LDR series and appears to be a safe and effective alternative to LDR therapy for the treatment of cervical carcinoma. Studies from the major centers report the five-year survival rate of cervical cancer as. 78-86$\%$ for Stage 1, 68-85$\%$ for stage 11, and 38-56$\%$ for Stage III. World-wide questionnaire study and Japanese questionnaire survey of multiple institutions showed no survival difference in any stages and dose-rate effect ratio (HDR/LDR) was calculated to be 0.54 to 0.58. However the optimum treatment doses and fractionation schemes appropriate to generate clinical results comparable to conventional LDR schemes have yet to be standardized. In conclusion, HDR intracavitary radiotherapy is increasingly practiced in Korea and an effective treatment modality for cervical cancer. To determine the optimum radiotherapy dose and fractionation schedule, a nation-wide prospective study is necessary in Korea. In addition, standardization of HDR application (clinical, computer algorithms, and dosimetric aspects) is necessary.

• 한국재난정보학회 논문집
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• 제19권3호
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• pp.510-518
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• 2023

연구목적: 본 연구는 기존의 보이스피싱과 신종 보이스피싱의 특성 및 진행과정을 비교·분석하여 심리적 기재를 기반으로 한 신종 보이스피싱에 대한 대응방안을 마련하는 정책적 기초 자료를 제시하는 데있다. 연구방법: 기존 보이스피싱에 대한 연구와 신종 보이스피싱 시나리오를 중심으로 한 각종 포털사이트에 있는 피해사례 등을 통해 양자의 범죄 진행과정 및 특성을 비교·분석하였다. 연구결과: 범죄준비 단계에서는 양자 모두 심리적 기재를 기반으로 하지만, 신종 보이스피싱은 피해자를 기망할 수 있는 시나리오가 더욱 치밀하게 작성되었고, 범행대상 범위가 확장되었다. 범죄실행단계에서는 신종 보이스피싱의 경우 피해자를 사회적으로 고립시켜 피해자의 판단능력을 저하시키고, 수사기관의 수사를 더욱 어렵게 하였다. 마지막단계에서는 금품 갈취 등 범죄피해의 지속성과 확장 가능성이 나타났다. 결론: 보이스피싱을 비교·분석하여 보았을 때 범행 대상 및 범위 그리고 범죄전략, 수법 등에 차이가 있었으며, 이에 따른 피해발생 가능성도 훨씬 크기 때문에 보다 더 효율적이 대응전략이 마련되어야 할 것이다.

• Geomechanics and Engineering
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• 제12권3호
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• pp.399-415
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• 2017

A series of direct shear tests were conducted to investigate the frictional properties of the interface between structures and the filling soil of Chongqing airport fourth stage expansion project. Two types of structures are investigated, one is low carbon steel and the other is the bedrock sampled from the site. The influence of soil water content, surface roughness and material types of structure were analyzed. The tests show that the interface friction and shear displacement curve has no softening stage and the curve shape is close to the Clough-Duncan hyperbola, while the soil is mainly shear contraction during testing. The interface frictional resistance and normal stress curve meets the Mohr-Coulomb criterion and the derived friction angle and frictional resistance of interface increase as surface roughness increases but is always lower than the internal friction angle and shear strength of soil respectively. When surface roughness is much larger than soil grain size, soil-structure interface is nearly shear surface in soil. In addition to the geometry of structural surface, the material types of structure also affects the performance of soil-structure interface. The wet interface frictional resistance will become lower than the natural one under specific conditions.