• Speech Sciences
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• v.8 no.4
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• pp.171-184
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• 2001

American English vowels and Korean vowels were compared by the plotformant method. For American English vowels, six General American English speakers pronounced English words in the b_t environment. For Korean vowels eight Kyongsang dialect speakers and eight Seoul dialect speakers pronounced Korean words in the environments of k_t, p_t and t_t. The formant plots were obtained by plotting F1/F2 tokens of 13 American English vowels on the F1xF2 plane. In spite of personal variations the 13 vowel spaces of all six American English speakers maintained their relative positions with some overlaps. Clear distinctions were made between i-I, e-$\varepsilon$, u-$\sigma$, and o-c. The domain of c and $\alpha$ overlapped for three American English speakers, but it did not for three other speakers. The 8 Korean vowel spaces of Kyongsang dialect speakers and Seoul dialect speakers were very similar and maintained their relative positions. No distinction was made between e and $\varepsilon$. In contrast with American English e which is a neutral vowel, Korean e was a back vowel. The comparison of 13 American English vowel positions and 8 Korean Vowel positions is expected to shed some light on the errors of English vowel pronunciation of Korean learners.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.9
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• pp.103-109
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• 2007

LCD (Liquid Crystal Display) is widely used electronic product. It needs too many processes such as PECVD (Plasma Enhanced Vapor Deposition), Sputtering, Photo-lithography, Dry etch. Each process is important but inspection process is more important because most companies emphasis on the six sigma. Recently, LCD inspection system is composed with inlet, inspector, outlet air pads. LCD is inspected on air pad which is shooting air from air hole. This paper studies on pad design of air bearing for LCD inspection to minimize LCD fluctuation. This design is able to reduce fluctuation and then satisfies CCD inspectional range. Also inspection pad needs to adequate stable area.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.459-472
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• 2014

Storm surge height in the coastal area of Jeju Island was examined using the Princeton Ocean Model(POM) with a sigma coordinate system. Amongst the typhoons that had affected to Jeju Island for six years(1987 to 2003), the eight typhoons(Maemi, Rusa, Prapiroon, Olga, Yanni, Janis, Gladys and Thelma) were found to bring relatively huge damage. The storm surge height of these typhoons simulated in Jeju harbour and Seogwipo harbour corresponded relatively well with the observed value. The occurrence time of the storm surge height was different, but mostly, it was a little later than the observed time. Jeju harbour showed a higher storm surge height than Seogwipo harbour, and the storm surge height didn't exceed 1m in both of Jeju harbour and Seogwipo harbour. Maemi out of the eight typhoons showed the maximum storm surge height(77.97 cm) in Jeju harbour, and Janis showed the lowest storm surge height(5.3 cm) in Seogwipo harbour.

• Journal of Korean Society for Quality Management
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• v.32 no.2
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• pp.201-211
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• 2004

Process adjustment is a complimentary tool to process monitoring in process control. Process adjustment directs on maintaining a process output close to a target value by manipulating another controllable variable, by which significant process improvement can be achieved. Therefore, this approach can be applied to the 'Improve' stage of Six Sigma strategy. Though the optimal control rule minimizes process variability in general, it may not properly function when special causes occur in underlying process, resulting in off-target bias and increased variability in the adjusted output process, possibly for long periods. In this paper, we consider a responsive feedback control system and the minimum mean square error control rule. The bias in the adjusted output process is investigated in a general framework, especially focussing on stationary underlying process and the special cause of level shift type. Illustrative examples are employed to illustrate the issues discussed.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.388-393
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• 2004

Creep behavior of Ti had been studied in a stress from 9.8 to 29.4 MPa and temperature rang from 873K to 973K with a special reference to tertiary creep. It was found that stress exponent of Ti was larger than that of the general pure metal and the compound metal. The relationship between true strain and strain rate in tertiary creep was appeared as the equation, $ln{\dot{e}}$ = $ln{\dot{e}}_{0}$ + ${\Omega}$ e Also, Apparent activation energy of was appeared as 274.92kJ/mol by using the equation ${\dot{\varepsilon}}_{0}$ = A ${\sigma }_{0}^{\ast_0}$ exp$(-Q_{0}/RT)$

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.882-886
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• 2004

A nation have the regulation for a vehicle safety and interested in the side impact of a vehicle. But we spend a lot of money and time for the side impact test. So we must design a vehicle parts regard to the side impact test. This paper describes a new test method for side impact test. We used DFSS(Design For Six Sigma) process for design of door trim armrest. We searched the door trim armrest control factor and made the experiment plan. We researched the optimal design factor and improved the abdomen injury value of the human dummy.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.238-244
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• 2008

본 연구는 급변하는 경영환경에서 서비스 기업들이 빠르고 창의적인 혁신활동으로 기업의 문제를 해결을 지원하기 위한 문제해결 정보시스템을 설계 하고자 하는 연구이다. 이를 위해 창의적 혁신 기법인 TRIZ 혁신 기법과 고객관점의 최적화 기법인 6시그마 기법을 융합하여 CTQ를 중심으로 하는 3단계 문제해결 Logic과 이를 지원하는 정보 시스템 설계에 대한 Framework 및 속성들을 제시하였다. 또한 서비스 기업의 일반적 사례 적용을 통해 문제해결정보시스템의 활용 가능성을 확인 하였고, 이에 대한 문제해결 시스템 적용을 통해 서비스 기업들의 경영혁신을 고도화하여, 기업의 경쟁력을 향상할 수 있다는 점을 제시해 주고 있다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.280-281
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• 2008

In pursuit of decreasing noise and vibration, the electromagnetic active control mount(ACM) is developed which is corresponding with the tendency of greater fuel efficiency, higher engine power and lower lightweight vehicle. In process of developing the ACM, making patent searches and benchmarking are performed first, and then robust mount design which is reflected on the users' demand through Design For Six Sigma(DFSS) is carried out. The manufactured prototype of ACM is tested in various environmental conditions for the purpose of ensuring the performance quantitatively.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.500-504
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• 2004

본 논문에서는 한 중소기업을 상대로 진행된 게이트 도장 품질 개선을 위한 6시그마 프로젝트 과정을 소개한다. 프로젝트는 6시그마 개선활동의 로드맵인 DMAIC 절차를 따라 진행하였다. 먼저 Define 단계에서는 고객요구사항 파악을 위해 VOC 기법을 활용하여 CTQ를 선정하였다. Measure 단계에서는 프로세스 맵, 특성요인도, XY 매트릭스, FMEA등을 이용하여 주요 인자들을 규명하였다. Analyze 단계에서는 상관분석, ANOVA, 그래프 분석 등 각종 통계적 기법을 활용해 핵심입력변수인 'Vital Few's'를 규명한 후, Improve 단계에서 DOE를 통한 최적조건을 도출하였다. 또한 Control 단계에서는 최적조건을 유지하기 위한 관리계획 및 실수방지, 표준화 기법을 도입하였다. 이러한 개선 활동을 통해 개선 전 2.957 시그마 수준의 품질을 3.66 시그마 수준까지 높일 수 있었으며, 6천 3백만원의 비용절감을 할 수 있었다. 또한 본 논문에서는 중소기업에서의 프로젝트 진행의 문제점을 제시하였고, 그 해결방안에 대해서도 논하고자 한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.339-342
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• 2004

현재까지 많은 기업들이 정보화를 대세로 인정하고 IT 투자에 막대한 기업 자원을 투입하였다. 특히 닷컴 버블까지 발생했던 지난 몇 년 간 대다수 기업들은 경쟁에서 뒤처지지 않기 위해서 정보화 투자에 대한 효익을 간과한 채 투자에 힘써온 것이 사실이다. 미국의 조사 기관 중 하나인 메타 그룹이 발표한 자료에 따르면 2001년 한 해 동안 전 세계의 대다수 기업들이 IT 투자에 쏟은 투자액만 총 2조 2000억 달러에 달하지만 ROI 등을 고려하여 투자한 기업은 드물었다고 한다. 그러나 세계적인 경기 침체에 따라서 기업 가치에 특별한 효익을 가져다주지 못하다고 판단한 기업들은 IT 투자를 축소하고 있거나 투자 효익에 대한 검증을 원하고 있다. 따라서 본 연구에서는 이러한 평가 방법론 중 대표적인 방법론으로 성과 중심의 BSC(Balanced Scorecard) 방법론, 프로세스 관점에서의 CMM(Capability Maturity Model) 방법론, 운영 관점의 6 시그마 방법론에 대해서 서로 비교 분석해보고 특히 6 시그마 방법론이 두 방법론들 사이에서 제시해 줄 수 있는 공통 관계 및 인과 관계를 분석함으로써 성과 관리 및 프로세스 관리에 대한 관점을 제시하고자 한다.