• 한국정밀공학회지
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• 제20권6호
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• pp.151-159
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• 2003

This paper presents a new DFA methodology to estimate the standard assembly time and evaluate the assemblablity of a product. The assembly time is estimated with some decision and influencing factors of assembly using motion analysis. The assemblability is evaluated using weights of the decision and influencing factors and assembly difficulty scores, and the tables that include the time and score of assembly are suggested. Finally, a new DFA system supporting the DFA is implemented to help designers to analyze the product during the design process in concurrent engineering.

• 한국정밀공학회지
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• 제13권7호
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• pp.122-132
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• 1996

It can be expected that the tolerances of the parts are assigned systematically and thus the parts are designed considering the assemblability in advance in the design stage, if the tolerances can be stored together with the geometric model of the parts and the assemblability of the parts is verified in the computer. In other words, an example of the concurrent engineering is realized. To verify the concepts described above, a new method is proposed to verify the assemblability when the tolerance information and the geometric model of the parts of an assembly are given. This method determines the assemblability by subdividing the range of relative motion between parts until the subdivided region corresponding to free of interference can be found.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1995년도 추계학술대회발표논문집; 서울대학교, 서울; 30 Sep. 1995
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• pp.358-358
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• 1995

• 기계와재료
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• 제5권1호통권15호
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• pp.107-124
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• 1993

• 시스템엔지니어링워크숍
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• 통권7호
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• pp.10-13
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• 2006

• 기계와재료
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• 제2권4호통권6호
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• pp.18-35
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• 1990

• Molecules and Cells
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• 제40권1호
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• pp.45-53
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• 2017

Aberrant hypermethylation of Wnt antagonists has been observed in gastric cancer. A number of studies have focused on the hypermethylation of a single Wnt antagonist and its role in regulating the activation of signaling. However, how the Wnt antagonists interacted to regulate the signaling pathway has not been reported. In the present study, we systematically investigated the methylation of some Wnt antagonist genes (SFRP2, SFRP4, SFRP5, DKK1, DKK2, and APC) and their regulatory role in carcinogenesis. We found that aberrant promoter methylation of SFRP2, SFRP4, DKK1, and DKK2 was significantly increased in gastric cancer. Moreover, concurrent hypermethylation of SFRP2 and DKK2 was observed in gastric cancer and this was significantly associated with increased expression of ${\beta}-catenin$, indicating that the joint inactivation of these two genes promoted the activation of the Wnt signaling pathway. Further analysis using a multivariate Cox proportional hazards model showed that DKK2 methylation was an independent prognostic factor for poor overall survival, and the predictive value was markedly enhanced when the combined methylation status of SFRP2 and DKK2 was considered. In addition, the methylation level of SFRP4 and DKK2 was correlated with the patient's age and tumor differentiation, respectively. In conclusion, epigenetic silencing of Wnt antagonists was associated with gastric carcinogenesis, and concurrent hypermethylation of SFRP2 and DKK2 could be a potential marker for a prognosis of poor overall survival.

• 소음진동
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• 제7권4호
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• pp.689-700
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• 1997

There are many difficulties in designing the engine structure properly due to the strong conflicts between NVH characteristics and the high performance, light weight and low product cost. Many feasible noise reduction techniques should be carefully incorporated to meet such stringent noise requirements. It is also required that the engine development be carried out by introducing concurrent engineering, in which the analysis and test database are usefully applied to the detail designs from the 1st stage. This paper reviews the significance of the noise characteristics of the structure elements in relation to the combustion pressure. The mechanisms of the crank shaft rumbling, which is the main source having the bad influence on the sound quality, are also explained. The influences of dynamic behavior of engine structure on its noise are investigated, followed by discussions on experimental results of the features necessary for the design of low noise engine concepts.

• 기계저널
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• 제35권4호
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• pp.322-336
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• 1995

오늘날의 세계 시장에서는 그 경쟁이 점점 복잡해지고 있다. 이 경쟁에서의 승리는 적절한 시 기에 적절한 새모델을 제시하느냐에 달려 있다. 불행히도 제품설계 및 제조사이클에는 종종 많은 시간이 요구되는 루프가 포함되어 있다. 즉 설계변경과 재작업 사이클 때문에 시자출하 시간이 지연된다. 이러한 변화를 동적으로 취급하고 적절한 시점에 적절히 이동할 수 있는 전략을 개 발하는 것이 오늘날 세계경쟁에서의 성공에 필수적이다. 이러한 문제점들의 해결방안으로 동시 공학, 혹은 지식베이스 시스템을 포함하는 지식베이스 엔지니어링(KBE:knowledge-based engineering)이 소개되는데 이러한 지식베이스엔지니어링은 기존의 제품개발 방법론을 개선하기 위한 지능적인 설계도구로서 컴퓨터를 사용하는 새롭고 흥미로운 가능성을 제시한다. 이러한 설계도구는 조직적이고 체계적으로 지식을 수집하여 활용함으로써 동시공한(concurrent engineering)방법론을 효율적으로 수행하는 데에 매우 유용하다.

• ETRI Journal
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• 제31권6호
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• pp.809-811
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• 2009

We propose a novel simulation method for modeling the game of golf using SystemC, a system description language that allows modeling of a concurrent system's behavior. Utilizing the proposed simulator, we compare different outing formats of golf, namely, regular and shotgun, in terms of playing time. Our simulation results reveal that the shotgun format can take longer than the regular format if the number of groups in a golf course exceeds 33 for the scenario we tested, confirming the belief that the shotgun format can take longer than the regular format. We also justify our simulation by comparing the simulation and analytical results.