• 한국콘텐츠학회논문지
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• 제18권3호
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• pp.557-567
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• 2018

본 연구는 코스닥 IPO시장에서 공모주식 청약 시 일반투자자의 배정비율을 20%이상으로 규정한 2004년 3월부터 2013년 12월까지 코스닥 시장에 신규 상장한 모든 기업을 대상으로 일반투자자의 배정비율과 저평가율 간의 관계에 대해 실증분석 한다. 본 연구의 결과는 다음과 같이 요약될 수 있다. 일반투자자 배정비율의 20% 초과 여부가 저평가율에 있어 유의한 설명력을 갖는지 회귀식을 통해 검증한 결과 1% 유의수준 하에서 의미가 있다고 나타난다. 나아가 일반투자자의 배정비율도 5% 유의수준 하에서 저평가율에 대해 설명력을 갖는 것으로 나타난다. 저평가에 대한 가설은 여러 가지가 존재하지만, 일반투자자 배정비율이 높으면서 저평가가 뚜렷이 나타난다면, 상장 후 주가 및 실적에 대한 공모회사의 자신감을 볼 수 있는 간접적인 신호(Signalling)라고 볼 수 있다. 결론적으로 본 연구는 코스닥 IPO시장에서 공모주식 청약 시 일반투자자의 배정비율이 저평가 정도에 유의한 영향을 미치는 주요한 설명변수로 이용될 수 있음을 실증분석을 통해 확인한다.

• 한국구조물진단유지관리공학회 논문집
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• 제8권4호
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• pp.175-183
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• 2004

아치교량의 미관과 경제성을 고려할 때 가장 중요한 요소가 라이즈 비 이며, 이러한 라이즈 비를 결정하는데 있어 현재는 자중에 의한 영향만을 고려하고 있다. 본 연구에서는 아치교량의 라이즈 비 검토시 현재 고려하고 있는 자중에 의한 영향뿐만 아니라 최근 중요시 되고 있는 지진하중에 대한 동적안정성 문제를 라이즈 비 결정인자로 추가하여 자중에 의한 라이즈 비 결정이 가지고 있는 문제점에 대하여 검토하였다. 그 결과 라이즈 비 선정시 지진하중에 대한 동적안정성은 필히 고려되어야 할 것으로 판단되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제29권2호
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• pp.185-193
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• 2005

The present study composed a diesel-atkinson cycle of high expansion as a method of achieving high efficiency in diesel cycle engines. It also interpreted the cycle engine thermodynamically analysis to determine the possibility of the improvement of thermal efficiency and clarified the characteristics of several factors . According to the result of theoretical analysis, heat efficiency was highest when expansion-compression ratio Reど:1. In addition. diesel engines with high apparent compression ratio had higher expansion-compression ratio than otto engines and consequently their effect of high expansion was high. which in turn enhanced thermal efficiency. When the atkinson cycle was implemented in a real diesel engine by applying the miller cycle through the variation of the closing time of the intake valve, the effective compression ratio and the quantify of intake air decreased and as a result, the effect of high expansion was not observed. Accordingly. the atkinson cycle can be implemented when the quantity of intake air is compensated by supercharge and the effective compression ratio is maintained at its initial level through the reduction of the clearance volume. In this case. heat efficiency increased by $4.1\%$ at the same expansion-compression ratio when the apparent compression ratio was 20 and the fuel cut off ratio was 2. As explained above, when the atkinson cycle was used for diesel cycle. heat efficiency was improved. In order to realize high expansion through retarding the intake value closing time, the engine needs to be equipped with variable valve timing equipment, variable compression ratio equipment and supercharged Pressure equipment. Then a diesel-atkinson cycle engine is realized.

• 한국잠사곤충학회지
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• 제20권2호
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• pp.6-9
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• 1978

잠 103$\times$잠 104 와 그 역교, 잠107$\times$잠108 및 그 역교를 공시하여 6개 업자의 잠종비중별 부화율 및 실용부화율 시험에서 얻은 결과는 1. 난비중을 세분하여 부화율 실용부화율을 보면 경비중에 비하여 중비중 및 중비중의 난이 부화율 및 실용부화율이 높았다. 2. 일모체는 중모체에 비하여 경비중 및 중비중난에서 부화률이 높았고 실용부화율은 경비중난에서만 높았다. 3. 중모체는 비중별 실용부화율 및 부화율의 차이가 컸으며 이에 비하여 일모체는 부화율에는 차이가 없으나 실용부화율에서 비중별 차이를 인정할 수 있었다. 4. 제조업자별 중비중난의 부화율 및 실용부화율의 차이는 없으나 경비중, 중비중난에서는 현저한 차이를 나타내었다.

• Geomechanics and Engineering
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• 제13권4호
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• pp.601-619
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• 2017

Cantilever retaining wall movements generally depend on the intensity and duration of ground motion, the response of the soil underlying the wall, the response of the backfill, the structural rigidity, and soil-structure interaction (SSI). This paper investigates the effect of material properties on seismic response of backfill-cantilever retaining wall-soil/foundation interaction system considering SSI. The material properties varied include the modulus of elasticity, Poisson's ratio, and mass density of the wall material. A series of nonlinear time history analyses with variation of material properties of the cantilever retaining wall are carried out by using the suggested finite element model (FEM). The backfill and foundation soil are modelled as an elastoplastic medium obeying the Drucker-Prager yield criterion, and the backfill-wall interface behavior is taken into consideration by using interface elements between the wall and soil to allow for de-bonding. The viscous boundary model is used in three dimensions to consider radiational effect of the seismic waves through the soil medium. In the seismic analyses, North-South component of the ground motion recorded during August 17, 1999 Kocaeli Earthquake in Yarimca station is used. Dynamic equations of motions are solved by using Newmark's direct step-by-step integration method. The response quantities incorporate the lateral displacements of the wall relative to the moving base and the stresses in the wall in all directions. The results show that while the modulus of elasticity has a considerable effect on seismic behavior of cantilever retaining wall, the Poisson's ratio and mass density of the wall material have negligible effects on seismic response.

• International Journal of Air-Conditioning and Refrigeration
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• 제15권3호
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• pp.114-121
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• 2007

In this study, a modified reverse flow type, one of the triple effect absorption cycles, is studied for performance improvement. The cycle simulation is carried out by using EES(Engineering Equation Solver) program for the working fluid of $H_2O/LiBr$ solution. The split-ratios of solution flow rate, UA of each component, pumping mass flow rate of solution are considered as key parameters. The results show that the optimal SRH (split ratio of high side) and SRL (split ratio of low side) values are 0.596 and 0.521, respectively. Under these conditions, the COP is maximized to 2.1. The optimal pumping mass flow rate is selected as 3 kg/s and the corresponding UAEV A is 121 kW/K in the present system. The present simulation results are compared to the other literature results from Kaita's (2002) and Cho's (1998) triple effect absorption systems. The present system has a lower solution temperature and a higher COP than the Kaita's modified reverse flow, and it also gives a higher COP than the Cho's parallel flow by adjusting split ratios.

• 대한치과보철학회지
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• 제38권3호
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• pp.348-357
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• 2000

The purpose of this study is to examine the effect of partial osseointegration situation on bone loading patterns around two different free-standing screw shaped implants (Nobel Biocare, Gothenburg, Sweden and Degussa-Huls, Hanau, German). Two dimensional axisymmetric Finite element models of two implants(10mm length and 4mm diameter) were created according to different bone quantity, quality and osseointegration ratio in maxilla and mandible bone. At the same time uni-cortical and hi-cortical fixation were analyzed. Generally, full bond case showed less stress than partial bond case in overall area and mandibular model showed less amount of stress than that of maxilla model. Maximum stress of the Branemark implant is higher than that of ANKYLOS regardless of bonding ratio at crestal and apex region. However, more stress concentration was noted in ANKYLOS implant at screw body area especially in mandible. The effect of bicortical fixation on crestal bone stress reduction is dramatical in mandible however, there was no significant effect in maxillary case. The effect of partial bond on stress distribution was more significant at screw body and apex region than in crestal region. Partial bond cases demonstrated greater stress accumulation in trabecular bone than cortical bone. It is concluded that the more accurate model of implant and bone which affects stress and strain distribution is needed to mimic in vivo behavior of implants.

• The Korean Journal of Physiology
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• 제12권1_2호
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• pp.15-23
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• 1978

The action of ascorbic acid on the sodium Plus potassium activated ATPase activity in the rabbit red cell membrane has been investigated and the experiments were also designed to determine the mechanism of action if ascorbic acid on the ATPase activity The following results were observed. 1. The activity of the NaK ATPase from red cell membrane is stimulated by ascorbic acid and the concentration of ascorbic acid for maximal activity is about 8 mM. 2. The activating effect of ascorbic acid on the ATPase activaty, with a given concentration of sodium in the medium, is increased by raisins the potassium concentration but activity ratio is decreased. 3. The activating effect of ascorbic acid on the ATPase activity, with a given concentration of potassium in the medium, is increased by raising the sodium concentration but activity ratio is decreased. 4. The action of ascorbic acid on the ATPase activity is stimulated by calcium ions and activity ratio is increased by raising the calcium concentration. 5. The activating effect of ascorbic acid on the ATPase activity was not related to the sulfhydryl group of cysteine or the hydroxyl group of threonine. 6. The activating effect of ascorbic acid on the ATPase activity is due to amino group and carboxyl group of the enzyme of NaK ATPase.

• 응용통계연구
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• 제19권1호
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• pp.163-170
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• 2006

역학(epidemiology) 또는 임상(clinic) 자료를 분석하기 위한 주효 측도의 선택에 대한 연구가 계속되고 있지만, 주효 측도들이 일반적인 함수 형태로만 표현되는 경우에는 주효 측도들의 특징이나 관계를 이해하는 것이 쉽지 않다. 이 논문에서는 주효 측도의 선택 문제 보다는 이변량 자료에 대한 주효 측도 중에서 위험도차이(risk different: RD), 상대위험률(relative risk: RR), 그리고 교차비(odds ratio: OR)를 방사형 그림(radar diagram)을 사용하여 나타내고 이 그림을 이용하여 이들의 특성이나 관계를 살펴보았다. 방사형 그림은 이 측도들을 이해하는데 좋은 도구가 될 것이다.

• 설비공학논문집
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• 제28권11호
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• pp.434-443
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• 2016

The evaporation of water from an aqueous solution is widely used in the food, desalination, pulp, and chemical industries. Usually, a large amount of energy is consumed in the evaporation process to boil off water due to atmospheric pressure. As a way of improving the energy efficiency of the evaporation process, the combination of multiple effect evaporation and thermal vapor recompression has been proposed and has become a successful technique. In this study, 4 multiple-effect falling film type evaporators for sugar solution are designed and the energy efficiency of the system is analyzed in response to the selection of the steam ejector position. Energy efficiency is increased and vapor is more compressed in the steam ejector as the Thermal Vapor Recompression (TVR) is arranged in the rear part of the evaporator system. A simplified 0-dimensional evaporator model is developed using non-linear equations derived from mass balances, energy balances, and heat transfer equations. Steam economy is calculated to compare the evaporation performance of the 4 proposed evaporators. The entrainment ratio, compression ratio, and expansion ratio are computed to check the ejector performance.