• 디지털콘텐츠학회 논문지
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• 제15권2호
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• pp.301-308
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• 2014

최근에 데이터가 대용량화됨에 따라 정보 저장의 중요성이 부각되고 있다. 본 연구는 대용량 저장장 치에 많이 사용되는 2.5인치 HDD에 대해서 가속 시험결과를 토대로 연간 제품 고장률을 예측하고 사용 환경에 대한 연간 제품 고장률과의 차이를 최소화 시키는 새로운 방안을 제시하고자 한다. 반품된 2.5인치 HDD 309개의 정보를 분석하여 실사용 환경의 시간당 전송량을 구했고, 가속 수명시험으로부터 가속 시험조건의 시간당 전송량을 구한 후, 사용률에 대한 가속 계수를 산출했다. 온도에 대한 가속 계수, 사용률에 대한 가속 계수와 고장률로 연간 제품 고장률을 예측하였다. 가속 시험의 시간당 전송량 81.4GB/hour와 사용자 93.4 %까지 대표하는 실사용 환경의 시간당 전송량은 5.8 GB/hour로 산출한 사용률에 대한 가속 계수는 14.1이다. 실사용 환경의 연간 제품 고장률은 1년 이후 안정화 되었으며, 이때 연간 제품 고장률은 0.3~0.378 % 이내에서 변동 하였다. 본 연구를 통하여 예측된 연간 제품 고장률은 0.4 %로 실사용 환경의 연간 제품 고장률과 75~94%의 일치됨을 보였다. 본 연구는 제조사의 가속수명 결과로 실사용 환경을 연간 제품 고장률을 예측하는 방법에 영향을 줄 것이다.

• Clinical and Experimental Reproductive Medicine
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• 제12권1호
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• pp.47-70
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• 1985

This study was presented of the 1,872 cases of infertile couples who visited and examined at the sterility clinic of Department of Obstetrics & Gynecology, Seoul National University Hospital from Sept., 1980 to Dec., 1983. Age, duration of infertility, past medical history, and other general factors were analyzed, and the factors responsible for infertility were classified and discussed. Mode of treatment, outcome of pregnancy, pregnancy rate responsible for each factor were also presented. The results were as follows: 1) The infertility was primary in 1,128, or 60.3% and secondary in 744, or 39.7%. 2) The age between 26 and 30 years of age comprised about one half of the total patients. 3) The duration of infertility between 1 and 4 years comprised about three quarters of the total patients, and the mean duration was 3.8 years. 4) The most common medical history in primary infertility was tuberculous disease, and that in secondary infertility was history of previous laparotomy. 5) About two thirds of antecedent pregnancies were abortion. 6) The major etiologic factor of infertility were male factor in 12.3%, tubal factor in 38.8%, ovulatory failure in 25.4%, uterine factor in 8.8%, cervical factor in 5.2%, peritoneal factor in 9.5%, and no demonstrable cause in 11.3%. 7) The types of male factor were azoospermia in 61.6%, oligospermia in 25.8%, low motility in 11.6%, and other abnormality in 1.0%. 8) The types of ovulatory failure were ovarian failure in 7.4%, hypothalamo-pituitary failure in 8.1 %, hypothalamo-pituitary dysfunction (including Polycystic ovarian syndrome) in 30.2%, and hyperprolactinemia in 22.4%. 9) The types of uterine factor were endometrial tuberculosis in 27.5%, uterine synechia in 33.8%, uterine anomaly in 19.7%, myoma and polyp in 9.1 %, and luteal phase defect in 9.9%. 10) The types of peritoneal factor were pelvic adhesion in 80.9% and endometriosis in 19.6%. 11) Surgeries were done in 408 patients, and they were salpingolysis, lysis of extraadnexal adhesion, salpingostomy, fimbrioplasty, ovarian wedge resection for polycystic ovarian disease, tubo-tubal anastomosis, and tubo-uterine implantation in orders. 12) 243 pregnancies were achieved during the infertility work-up, of which livebirth was 46.5%, ectopic pregnancy was 7.4%, spontaneous abortion was 7.8%, and on-going pregnancy or lost to follow-up was 36.2%. 13) Pregnancy rates in various factors were male factor in 18.7%, ovulatory factor in 31.7%, tubal factor in 24.2%, uterine factor in 34.6%, cervical factor in 19.0%, peritoneal factor in 29.0%, combined factors in 10.5%, and unexplained infertility in 37.1%. Pregnancy rate in whole patients was 25.2%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.609-614
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• 2001

This paper is to explain reasonable shear behavior that can apply usually to reinforced concrete beams on the basic concepts of existent analysis and experimental research information. This study is succession $paper^{2) 3) 4) 5)}$ of treatise announced in existing and main control variable of reinforced concrete beams with stirrups used internal force state factor($\alpha$). Shear failure of reinforced concrete beams with stirrups is Influenced greatly because of the actual geometrical shape(a/d) of the concrete and flexural reinforcement steel ratio, stirrup reinforcement ratio and concrete compression strength, size effect etc. Therefore, shear behavior of reinforced concrete beams with stirrups that flexural crack is happened can be explained easily through proper extent proposal of internal force state factor($\alpha$) that express internal force state flowing. Use existent variable truss model by analysis model to explain arch action. Also, wish to compose each failure factors and correlation with internal force state factor by function, and when diagonal cracks happens, internal force state factor($\alpha$) study whether shear stress and some effect are.

• Industrial Engineering and Management Systems
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• 제8권4호
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• pp.247-256
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• 2009

In mass production industries such as steel making that have large equipment, sudden stops of production process due to machine failure can cause severe problems. To prevent such situations, machine diagnosis techniques play important roles. Many methods have been developed focusing on this subject. In this paper, we propose a method for the early detection of the failure on rotating machine, which is the most common theme in the machine failure detection field. A simplified method of calculating autocorrelation function is introduced and is utilized for ARMA model identification. Furthermore, an absolute deterioration factor such as Bicoherence is introduced. Machine diagnosis can be executed by this simplified calculation method of system parameter distance with weight. Proposed method proved to be a practical index for machine diagnosis by numerical examples.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권2호
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• pp.93-96
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• 2014

RFID (Radio Frequency IDentification) system is recognition technology which can maintain various object's information. Reliability of RFID tags is the most important factor in RFID system. In this paper, we proposed ALT (Accelerated Life Test) method for UHF RFID tags. Temperature and humidity were adopted as stress factors and the accelerated life tests were conducted in three different conditions. We performed failure analysis for identifying failure mechanism and statistical analysis of test data. In the statistical analysis, we employed Inverse Power law for relationship between tag's life and stress. Through the statistical analysis, we proposed acceleration factor for several levels of temperature-humidity. The reliability qualification test plans were also designed for the tag's target reliability.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.643-650
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• 2002

The large planar failure has occurred in a rock cut slope of highway construction site in Boeun. This area is considered as unstable since the discontinuities whose orientations are similar to the orientation of the failure plane, are observed in many areas. Therefore, several analysis techniques such as SMR, stereographic analysis, limit equilibrium, numerical analysis, which are commonly used in rock slope stability analysis, are adopted in this area. In order to analyze the stress redistribution and nonlinear displacement caused by cut, which are not obtained in limit equilibrium method, the UDEC and shear strength reduction technique were used in this study Then the factors of safety evaluated by shear strength reduction technique and limit equilibrium were compared. In addition, the factor of safety under fully saturated slope condition was calculated and subsequently, the effect of the reinforcement was evaluated.

• 한국전산구조공학회논문집
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• 제34권6호
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• pp.393-401
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• 2021

본 논문에서는 폭발하중을 받는 부재의 저항성능 평가를 위한 모멘트-곡률 관계 기반 수치해석 기법을 소개한다. 직접전단 파괴 모드를 고려하기 위하여 경험적인 직접전단응력-슬립양 관계를 기반으로 하는 무차원 스프링 요소를 도입하였다. 재료에 대해 정의된 동적증가계수 식을 바탕으로 단면의 모멘트-곡률 관계에 직접적으로 적용가능한 단면의 곡률 변화율에 따른 동적증가계수 식을 제작하였다. 또한 부착슬립의 영향을 고려하기 위하여 소성힌지영역 내에 등가 휨강성을 도입하였다. 제안된 수치해석 모델의 타당성 검증을 위하여 실험결과와의 비교연구를 수행하였으며, 단자유도계 모델의 해석결과와의 비교를 통해 본 수치해석 모델의 우수성을 확인하였다. P-I 선도를 제작하여 부재의 휨 파괴 및 직접전단 파괴에 대한 저항성능을 평가하였으며, 매개변수 연구를 수행하여 P-I 선도 및 저항성능의 변화를 확인하였다.

• 한국건설관리학회논문집
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• 제13권3호
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• pp.78-88
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• 2012

국내의 건설실패 관련 연구는 체계화된 실패정보 분류체계 및 실패정보의 활용을 위한 방안을 제시하는 것에 초점을 맞추고 있다. 그러나, 건설현장의 한정된 관리자가 건설실패를 유발하는 다양한 원인에 대한 예방대책을 수립하는 것은 한계가 있다. 따라서, 효율적인 건설실패 예방활동이 이루지기 위해서는 많은 실패원인에 대한 정량적 평가를 통해 우선순위를 정하여 효율적인 예방대책이 수립되어야 한다. 이에 본 연구는 정량적인 평가를 통해 실패를 유발하는 핵심관리요인을 도출 할 수 있도록 FMEA(Failure Mode and Effect Analysis) 기법을 활용한 건설실패 핵심관리요인 선정방법을 제시하고, 공동주택 골조공사를 대상으로 핵심관리요인을 분석하는 것을 목적으로 하였다. 이를 위해 FMEA 기법의 위험도를 실패 위험성과 예방성으로 구분하여 평가할 수 있도록 하였다. 본 연구에서 제시한 핵심관리요인 평가방법은 건설실패의 사전예방대책을 효율적으로 수립하는데 활용될 수 있으며, 향후 유사한 연구를 통해 프로젝트 수행 단계별 혹은 다양한 시설 및 공종에 대한 핵심관리요인을 도출하는데 활용될 수 있을 것으로 기대된다.

• 한국병원경영학회지
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• 제1권1호
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• pp.136-153
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• 1996

The purpose of this study is to identify the factors hindering hospital reengineering project in one university hospital. The data was collected by the self-administered Questionnaire to 288 members of the hospital in Pusan on April 5-18, 1996. This study took some statistical methodologies, such as descriptive analysis, factor analysis and logit model analysis. The results were as follows; First, in the descriptive analysis for whether the hospital reengineering named RUSH94 was a success or not, the subjects judged that it was not successful and regarded their fable mutual communication as the main factor. Second, in the reason of failure at the reengineering project, the group who thought that the failure factor was the lack of mutual consensus checked the scores of the first factor produced from the factor analysis.

• Journal of Chest Surgery
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• 제23권2호
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• pp.275-284
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• 1990

A serious problem after cardiovascular surgery known as Multiple Organ Failure[MOF] whereby several vital organs successively demonstrate dysfunction in spite of intensive postoperative treatment has recently arisen. We have made a retrospective study of the clinical records of 137 patients who underwent cardiovascular surgery during past two years [1987-1988]. Fourteen patients [10%] developed multi-organ failure postoperatively with the results of seven death [50%]. In fatal group, preoperative poor cardiac function [Cardiac Index<2.0L/min/m2] was considered important prognostic factor and infection 5 disseminated intravascular coagulation complicating gastrointestinal bleeding were the leading cause of death. In conclusion, evaluation of multiple factors concerning multi-organ failure demonstrates preoperative poor functional preservation of vital organs is the main factor. So early diagnosis k management for each of the failing organs & prevention of infection are mandatory of the treatment of these critically ill patients.