• 한국자동차공학회논문집
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• 제7권7호
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• pp.242-249
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• 1999

Spot welding is very important and useful technology in fabrication of an automobile body structure. Because fatigue strength of the spot welding point is however considerably lower than parent metal due to stress concentration at the nugget edge, accurate stress analysis and fatigue stength evaluation of spot welded lap joint are very important to valuate the reliability and durability of automobile body structure and to establish a criterion of long life fatigue design. Many invetigators have studied so far onsystematic fatigue strength evaluation with various methods. It is however necessary to verify their reliability and abailability for practical application to fatigue design of spot welded structure, Thus,in this study, fatigue strength evaluation methods of spot welded lap joint. which are the maximum principal stress method. the fracture and availability with the Weibull probability distribution. From the results, it was found that reliability and availability withe the Weibull probaility distribution. From the results, it was found that reliability and availability of the suggest fatigue strength estimation methods methods were higher than $\Delta$P-$N_f$ relation. However, among them , reliability of the maximum pricipal stress method was the highest.

• 전자공학회논문지A
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• 제33A권10호
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• pp.130-138
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• 1996

The size of a device needs to scale down to increase its integrity and speed. As the size of the device is reduced, the hot-carrier degradation that severely effects on device reliabilty is concerned. In this paper, sub-micron buried-channel P-MOSFETs were fabircated, and the hot-carrier effects were invetigated. Also the hot-carrier effect in the buired-channel P-MOSFETs and the surface-channel P-MOSFETs were compared with simulation programs using SUPREM-4 and MINIMOS-4. This paper showed that the electric characteristics of sub-micron P-MOSFET are different from those of N-MOSFET. Also it showed that the punchthrough voltage ( $V_{pt}$ ) was abruptly drop after applying the stress and became almost 0V when the channel lengths were shorter than 0.6.mu.m. The lower punchthrough voltage causes the device to operte poorly by the deterioration of cut-off characteries in the switching mode. We can conclude that the buried channel P-MOSFET for CMOS circuits has a limit of the channel length to be around 0.6.mu.m.

• 한국생산제조학회지
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• 제21권5호
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• pp.836-841
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• 2012

The repair of road pavement and manhole has been resulted long construction times and traffic jams, environmental pollution from construction wastes, and budget waste due to excessive construction costs. In order to resolve such problems, we have developed the new construction method using C-ring, which can fix and raise the manhole securely. This technology is the method by driving in a wedge after inserting C-ring and expanding it in order to raise manhole to the regular height. This has been approved by the test reports of KOLAS(Korea Laboratory Accreditation Scheme), and was confirmed safety, durability and reliabilty in result. In this paper we approved this technology was able to short working times to around 20% and construction costs to around 50% with compare other construction methods. Also, environmental pollution and civil complaints will be prevented because there will be no longer any noises, vibrations, dust, or construction wastes.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.17-22
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• 2009

Reliability analyses were performed to quantify the risk in axially loaded large-scale pile foundations in consideration of pile-soil interaction and uncertainties on various design variables. The finite difference method based on an equivalent soil spring model and a load transfer method and Monte Carlo simulation method are integrated in the framework of reliabilty analysis. The applicability and efficiency of the proposed method in the safety assessment of axially loaded pile-soil system was verified using a realistic example. Since the proposed method can explicitly consider uncertainties in various design variables, and quantify failure probability of a pile foundation, it can be used to estimate risk, to obtain basic informations for life cycle cost analysis, and to develop code requirements for a reliability-based design of pile foundations.

• Corrosion Science and Technology
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• 제19권5호
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• pp.265-280
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• 2020

External corrosion of buried pipes can be controlled using both coating and cathodic protection. However, deterioration of the coating can occur due to several reasons. The detection reliabilty of coating flaw detection methods is affected by interference such as metal objects connected to rectifiers and copper grids. When performing parallel direct current voltage gradient (DCVG) inspection, a sine wave form without potential reversal in voltage gradient appears in the area where the interference exists. However, this area may be not identified using existing methods. The objective of this study was to determine the effect of analyzing direction on the reliability of coating flaw detection of pipes buried in soil using a multi-electrode detector. DCVG on the buried pipe was measured along the buried pipe. This measurement parallel to the pipe was repeated. Measured data were analyzed for parallel, vertical, and diagonal directions. The reliability of coating flaw detection was improved by up to 46.4% compared to the conventional method.

• 한국조리학회지
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• 제22권4호
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• pp.156-169
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• 2016

본 연구의 목적은 중국 소비자를 대상으로 한국 라면 포장 디자인 속성과 라면 이미지, 그리고 라면 선택간의 관계를 연구하는데 있다. 한국 표본 라면으로 신라면, 짜파게티, 열무비빔면, 사리곰탕면, 참깨라면 등을 선택하였다. 본 연구의 결과를 정리하면 다음과 같다. 첫째, 중국 소비자들은 선호하는 라면으로 신라면을 가장 많이 선택하였고, 그 다음으로 열무비빔면, 짜파게티, 사리곰탕면, 참깨라면의 순으로 선택하였는데 라면 이미지에서는 신라면, 짜파게티, 열무비빔면, 참깨라면, 사리곰탕면의 순으로 높게 나왔다. 라면 포장 디자인 속성별로 대중성과 품질안정성에서 대부분 유의적인 차이가 있었으나 매력성과 건강성에서는 대부분 유의적인 차이가 없었다. 셋째, 신라면은 대중성, 품질 안정성이, 짜파게티에서는 품질 안정성이, 사리곰탕면에서는 품질 안정성과 건강성이 유의적인 정(+)의 영향력이 있었으나 사리곰탕에서는 매력성이 유의적인 부(-)의 영향력이 있었다.

• 조명전기설비학회논문지
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• 제12권1호
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• pp.35-44
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• 1998

본 연구에서는 전류스트레스 및 필터소자의 용량저감을 고려한 다이오드 정류기의 입력LC필터 설계법을 기술하였다. 입력교류전류의 제3고조파 성분에 대하여 무한한 임피던스를 갖도록 LC병렬 공진회로와 출력측 직류콘덴서로 구성된 새로운 필터를 단위법(Per Unit)에 의해 설계하였다. 제안된 LC필터를 다이오드정류기에 적용하여 정상상태에서 실험한 결과, 입력교류전류의 제3고조파성분을 8.8〔%〕로 감소시켰으며, 입력역률은 종전의 표준형의 입력역률이 0.76인데 비하여 0.913으로 개선시켰다. 또한 필터소지자의 전압.전류용량감소와 함께, 설계된 입력LC필터는 다이오드 정류기계통에 악영향을 미치지 않았으며, 따라서 종래의 표준형 LC필터에 의한 방법과 비교하여 제안된 방법이 83.5〔%〕의 저용량의 필터로도 고역률의 정류가 가능함을 입증하였다.

• 정보처리학회논문지C
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• 제17C권4호
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• pp.315-326
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• 2010

21세기를 막 들어선 세계는 과거 산업혁명, 종교개혁 등에 전혀 뒤쳐지지 않는 정보사회의 변화의 소용돌이에 휘말리고 있다. 이러한 정보사회를 설명할 수 있는 가장 일반적인 관점이 바로 기술결정론이라고 말할 수 있을 것이다. 정보기술이 곧 특정한 모습의 정보 사회를 가져올 것이라는 믿음이다. 기술 결정론이란 기술변화의 경로가 필연적이며 특정한 사회 변화를 요구한다는 견해를 의미한다[2]. 그러나 기술이 특정한 사회 변화를 요구함에 있어서, 기술의 발전의 정도 또한 중요하지만 기술의 신뢰감도 사회를 변화시키는 데 커다란 기여를 하게된다. 이러한 전제로 본 연구에서도 인터넷 기술에 대한 사람들의 신뢰감 정도에 따라 사회 변화와 개인의 변화가 다르게 나타날 수 있다는 견해를 가지고 진행하였다. 인터넷 익명성의 신뢰도에 따른 실명제의 선호도와 이용자의 행위에 미치는 영향력을 일반 사용자와 인터넷 관련 업계 종사자 간의 차이를 설문을 중심으로 분석하고, 인터넷 익명성의 가능성 및 당위성 그리고 역기능에 대한 해소방안을 제안하여 실명제의 논의와 인터넷 웹사이트의 익명성 정책에 대한 기준 자료를 제시하는데 그 목적을 두고 살펴보고자 한다.

• 한국정보전자통신기술학회논문지
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• 제10권5호
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• pp.469-475
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• 2017

소프트웨어 개발시행 과정에서 소프트웨어 신뢰성은 매우 기본적이고 필수적인 문제 중에 하나이다. 소프트웨어 고장현상을 파악하기 위하여 비동질적인 포아송 과정에서 순간 고장률인 강도함수가 고장시간에 독립적으로 일정하거나, 증가형 혹은, 감소형 추세를 가질 수 있다. 본 논문에서는 소프트웨어 설계 과정에서 강도형태가 감소패턴을 따르는 랜들리 수명분포와 증가하다가 감소하는 어랑수명 분포를 활용한 소프트웨어 신뢰속성 모형에 대하여 신뢰도 장단점에 관한 연구를 하였다. 소프트웨어 고장현상을 파악하기 위하여 모수추정은 최우추정법을 적용하였다. 따라서, 본 논문에서는 소프트웨어 고장시간 자료를 적용하여 소프트웨어 신뢰도를 비교하고, 평가하였다. 그 결과, 랜들리 모형이 어랑분포 모형보다 신뢰도가 상승하는 것으로 나타났으나, 어랑분포 모형에서는 형상모수가 높을수록 높은 신뢰도를 나타내는 추세를 보였다. 본 논문를 통하여 소프트웨어 기획 부서에서는 특정한 수명분포와 형상모수를 활용함으로서 소프트웨어 고장분석을 활용한 소프트웨어 신뢰성 모형에 대한 신뢰성 속성을 적용한 데이터 및 기본 지식을 제공함으로서 소프트웨어 설계에 실질적인 도움을 줄 수 있다.

• Journal of Preventive Medicine and Public Health
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• 제26권1호
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• pp.147-164
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• 1993

A study has been conducted on developing questionnaires to serve as on site diagnostic tools for the early detection of neuropsychiatric impairment among workers chronically exposed to low-level organic solvents. Two drafts of tentative questionnaires have been developed as follows; several question items were selected from questionnaires which were administered to workers exposed to organic solvents in previous studios and were grouped into each symptom category based on the presence of its association using Guttman scaling method, then these selected items were reviewed by neuropsychiatry specialists. The final draft of the questionnaire (total symptom score=36) was developed by selecting 33 question items which had more than a 0.88 Guttman coefficient of reproducibility in each symptom category from a pilot study in which these tentative questionnaires were administered to workers manufacturing soles. Three plants using organic solvents and one plant never using organic solvents as a control group were selected to test the reliability and validity of the developed questionnaires. The major organic solvent in the workplace environment detected by a personal air sampler and GC/MSD nab toluene. The concentration of toluene in air from the department using organic solvent was statistically different from that of the department never using organic solvent. The concentration of toluene from almost all of the workplace did not exceed the allowable level. There was no statistically significant difference between the concentration of urinary hippuric acid from the workers of the department using organic solvent and that of the department never using it. Total symptom score of the plant never using organic solvents was 9.8 and those of the three plants using organic solvents were 15.6, 14.7, and 13,7 respectively. In order to evaluate the validity of the questionnaires, the workers from two different departments of the plant in which usage of organic solvents are totally dofferemt were compared. The total symptom score was 17.8 for workers of the department using organic solvent and 13.5 for the department never using organic solvent and scores of each symptom group between exposure and non-exposure group also showed statistically significant difference. The finding that total symptom score of the exposure group increased as the duration of employment increased indirectly suggests the usefulness of the developed questionnaire to assess the health effects of chronic exposure to organic solvents. The correlation coefficient, which was calculated to evaluate the test-retest reliability, was 0.581 (p=0.001). The coefficient of Crohnbach which reflects the internal consistency of the questionnaire was 0.91. In conclusion, the reliabilty of the questionnaire was well maintained over the time lapse between the two administrations of the questionnaire and despite the seasonal difference.