• 대한기계학회논문집A
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• 제26권8호
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• pp.1577-1584
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• 2002

This paper develops a finite element model for studying the occupant behavior and injury cofficients of a large-sized cab-over type truck. Since it does not have a room to absorb collision energy and deformation in front of the passenger compartment the deformation is directly transmitted to the passenger compartment. Moreover, since its steering column is attached on the frame, severe deformation of the frame directly affects on the steering wheel's movement. Therefore, if the occupant behavior and injury coefficients analysis is performed using a finite element model developed based on a sled test, it is very difficult to expect acquiring satisfactory results. Thus, the finite element model developing in this paper is based on the frontal crash test in order to overcome the inherent problems of the sled test based model commonly used in the passenger car. The occupant behavior and injury coefficients analysis is performed using PAM-CRASH installed in super-computer SP2. In order to validate the reliability of the developed finite element model, a frontal crash test is carried out according to a test method used fur developing truck occupant's secondary safety system in european community and japan. That is, test vehicle's collision direction is vertical to the rigid barrier and collision velocity is 45kph. Thus, measured vehicle pulses at the lower parts of the left and right B-pilla., dummy chest and head deceleration profiles, HIC(head injury criterial) and CA(chest acceleration) values, and dummy behavior from the frontal crash test are compared to the analysis results to validate reliability of the developed model.

• 대한조선학회논문집
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• 제30권4호
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• pp.102-111
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• 1993

대형구조물에서 발생되는 피로 및 취성파괴에 대한 강도의 특성 평가는 대형구조물의 설계에서 중요한 검토 사항중에 하나이다. 본 논문에서는 대형선체 및 해양구조물과 같은 대형구조물의 기본 설계단계에서 파괴역학을 이용하여 피로균열 진전과 취성파괴 발생 및 정지등에 대한 구조물의 파괴 강도 특성을 파악하고 이것을 기초로 이에 대한 안전성평가를 검토하였다. 소형시험 결과에서 선체구조의 상갑판 전단부와 같은 복잡한 구조물의 피로파괴 강도특성을 정도가 높고 또한 간편하게 추정할 수 있는가에 대하여, 실물크기 부분구조 모델시험을 실시하여 이를 비교 검토하였다. 본 연구대상에서는 소형시험결과를 기초로해서 대형구조물의 피로균열전파거동을 예측할 수 있음을 보였다.

• 설비공학논문집
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• 제25권1호
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• pp.20-27
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• 2013

Numerical modeling of $CO_2$ water heater was conducted prior to optimal design of medium and large sized $CO_2$ water heater, and the experimental test with small sized $CO_2$ water heater having heat capacity of 4 kW was completed to verify the present numerical model. The present model estimated the experimental data of COP(coefficient of performance), heating capacity, and the hot water outlet temperature within the range of 3% to 8% of mean deviation. As increase of EEV(electric expansion valve) opening area, decreasing of heating capacity and the hot water outlet temperature, and increasing of COP were found in both experimental and numerical investigation.

• 품질경영학회지
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• 제42권3호
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• pp.477-496
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• 2014

Purpose: This paper has examined the impact of open innovation business model in technology commercialization with the data from 30 companies of manufacturing firms in South Korea. Methods: The findings provide support for distinguishing five hypotheses relating to development time, IP management, sales, firm size and R&D intensity. To test the hypotheses, data were collected using via e-mail and fax. Small and medium-sized (less than 300 employees) and large industrial firms were chosen for this study. Results: The result shows that openness in its business model is positively associated with successful technology commercialization. Conclusion: The major findings and the implications are: First, as the business model gets more open, development period of technology will be more favorable which gets benefit from rising costs of innovation. Second, as the business model gets more open, large portion of sales are created from new products. Thus, the problem of shorter product life in the market which affects large portion of market revenue can be solved through an open business model. Third, in general, R&D intensity, firm size and the level of IP management affect determination of business model types. The findings also suggest that companies need to increasingly address their external technology exploitation process instead of focusing on their internal innovation processes.

• 한국건축시공학회지
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• 제23권6호
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• pp.821-830
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• 2023

본 연구에서 회귀분석을 통한 중소형 건설 현장 추락재해에 대한 안전사고 위험요소를 추출하기 위해 첫째, 10년간의 중소형 건설 현장에서 발생한 추락재해에 대한 데이터를 수집하였으며 둘째, t-test를 통해 중소형 건설 현장과 대형 건설 현장 두 그룹 사이의 추락재해 발생 시 진료일수의 차이가 있다는 것을 증명하였다. 마지막으로 회귀분석을 실시하여 안전사고 위험 요소에 대한 회귀 모델을 도출하였다. 추락재해에 영향을 미치는 요소는 사고 시간, 사고 요일, 직업 분류 순으로 크게 작용하는 것으로 나타났다. 본 연구 결과는 건설 현장 규모에 따른 정책 개선 및 통계분석을 위한 기초자료와 중소형 건설 현장 위험 정량화 연구의 기초자료로 활용될 것으로 사료된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.7-12
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• 2004

Large-sized pins are usually used to lift and handle large low speed diesel engine crankshaft. There has then been a need to reduce and optimize the weight of the traditionally used pins. Making an hole by cutting the inside of the pin out was investigated in view of static and fracture strength. To compensate the stress increase caused by the introduction of the inner hole, the groove in the circumferential direction pre-existing on the pin is to be removed. Finite element analysis was carried out for both the original model and weight reduced model. Stress intensity factors for semi-elliptical defects assumed on the pin for the original model and weight reduced model was calculated using the ASME method and compared with the fracture toughness test result of the pin material. The diameter of the cutting hole for the revised model was determined based on the analysis results.

• 지질학회지
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• 제54권6호
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• pp.605-614
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• 2018

지질학적 현상을 연구하는 물리적 실험의 경우, 반복성 있는 현상 재현이 가능할 때 실험의 신뢰성을 증대시킬 수 있다. 본 연구에서는 인장력에 의해 발생한 정단층 구조를 대상으로 모형 토조를 이용한 벤치마크 실험을 수행하였다. 이를 위해 모형 실험의 상사성을 검토하고, 벤치마크 실험에서와 같은 방법으로 실험 재료와 인장조건, 그리고 경계조건을 설정하여 실험을 수행하였다. 또한 대형 원심모형실험시설을 이용하여 동일한 크기의 모형에서 원심중력가속도와 인장 속도를 변화시켜 인장 거동 시의 물리량에 대한 상사비를 고려하였다. 1 g 상태에서의 벤치마크 실험과 10 g 상태에서의 원심중력장에서 일정한 속도의 인장 응력을 구현하고, 지표면의 형상을 신뢰성 있게 계측하였다. 이를 통해 지각의 변형 실험 연구를 수행 시, 대형 원심모형실험의 신뢰성과 적용성을 평가하였다.

• 무역학회지
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• 제46권6호
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• pp.73-92
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• 2021

Small and medium-sized enterprises (SMEs) account for a large proportion of the total number of enterprises in many countries. The development of SMEs has contributed to job creation and economic benefits. Every government has formulated active diversification strategies to promote the export market of SMEs, but the performance of export capabilities remains insufficient. The primary purpose of this study is to examine the effectiveness of export credit insurance in promoting SME export performance in Canada. Using data from 2008-2017, the augmented Dickey-Fuller (ADF) model to test the stationarity of the concerned variables and the error correction model (ECM) and autoregressive distributed lag (ARDL) cointegration test to empirically investigate the cointegration relationship between the research targets. The results represent the positive and critical impact of export relative price and domestic demand pressure on Canada's export performance, and the negative impact of the export volume index at a significant level. Regrettably, the impact of export credit insurance on the export performance of Canadian SMEs is considered exaggerated overall. In view of this result, it is necessary for the Canadian government to enact policies based on the current market status. And enhance confidence among SMEs to begin exports and diversify their markets rather than focusing only on the domestic or US market, especially given the impact of COVID-19. From the case of Canada, Korean government can attempt to learn from them to conduct more efficient strategies for SMEs.

• 제어로봇시스템학회논문지
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• 제10권4호
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• pp.357-363
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• 2004

Earlier models of card vending machines have generally motion drives with high cost and large size. However, current trend in card vending machines requires low-cost, compact-sized and readily installable motion drives. This paper shows the operational principle of the motion drive of a card vending machine and then presents the performance test results of the motion drive with improved mechanisms proposed in the paper. The results show that the proposed mechanism is valid and improves the card dispensing performance. The proposed model in the paper is accepted and introduced in the actual production line.

• 경영과학
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• 제11권1호
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• pp.91-106
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• 1994

In mixed model assembly lines, products are assembled seqeuntially that have different combination of options specified by customers. In just in time (JIT) environment, production smoothing becomes an important issue for sub-lines which supply the necessary parts to each workstation of the assembly line. Another important issue is to avoid line stopping caused by work overload in workstations. To find a sequence which minimizes the costs associated with line stoppage and the option parts inventory level, a nonlinear mixed integer programming is formulated. Recognizing the limit of the Branch and Bound technique in large sized problems, a heuristic solution procedure is proposed. The performance of the heuristic is compared with the Branch and Bound technique through randomly generated test problems. The computational results indicate that on the average the heuristic solutions deviate approximately 3.6% from the optimal solutions.