• 한국생활과학회지
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• 제21권5호
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• pp.903-913
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• 2012

This study investigated the effects of depression, anxiety, and impulsiveness on suicidal thoughts among adolescents with the goal of better understanding the psychological needs of adolescents and to provide them with more effective counseling and guidance. Participants for this study included 340 high school students in their first and second year living in large urban centers. Respondents answered a questionnaire that documented their experiences related to depression, anxiety, impulsiveness, and suicidal thoughts. Data analysis was performed using the means, standard deviations, correlation analysis, and multiple regression using the IBM SPSS 19.0 statistics program. The results were as follows. There was no statistically significant difference in anxiety and impulsiveness based on gender. However, female respondents demonstrated a higher rate of suicidal thoughts than male respondents. Second, in both sexes, comparative analysis between depression, anxiety, impulsiveness, and suicidal thoughts revealed that respondents with higher levels of depression and anxiety demonstrated elevated levels of suicidal thoughts. Impulsiveness demonstrated a correlation with suicidal thoughts only for female participants. Third, while depression and anxiety affected suicidal thoughts in both male and female respondents, impulsiveness did not affect suicidal thoughts, with depression having the strongest effect.

• 한국경영과학회지
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• 제21권3호
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• pp.159-174
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• 1996

Facing decision-making tasks, managers frequently make judgments, However, since managers are human beings, the fficiency of their judgments is limited. Two major sources of inefficiency in their judgments have been recognized : one is systematic deviations from normatively preferred decisions, so called bias or incorrect intuition, and the other is inconsistency in their judgments, i. e. erratic decision making variance. Rather than bias, variance is really expensive or damaging. Thus, if the inconsistency inmanagers judgments is removed, performance could be by far improved by virtue of the reduced random variance. One of the approaches to improve managerial judgment is to simply bring managers together by effectively moderating the random variance due to inconsistency. Focusing on combining judgments, this paper addresses many relevant issues such as why combining and how to combine judgments, and suggests methods and models to effectively aggregate subjective judgments, We conduct an experiment to validata the effectiveness of combining jugements over individual judgments. Various combining schemes are also evaluated in terms of their prective accuracy. Among them, mean bias based wighting scheme turns out the best. However, when available information is not enough to estimate the expertise of judges, simple and robust equal weighting might be more efficient and productive. This urges an imperative future research on the issue of how many and which ones to combine from a large set of experts.

• 대한전자공학회논문지
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• 제9권2호
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• pp.17-23
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• 1972

본논문에서는 운동매질내에서 크기가 파장과 동등정도이거나 그 이상인 circular loop antenna의 방사특성을 전류분포가 정현파적인 경우에 대하여 고찰하였다. 고찰결과로는 방사특성이 매질속도의 영향을 받는다는 사실과 그 영향으로는 정지매질의 radiation pattern 과 비교하여 방사지향성이 loop antenna면에 평행인 매질속도성분에만 영향을 받고 수직성분속도에는 무관하며 radiation pattern의 최대지향성은 loop면에 평행인 속도성분방향으로 이동하고 이와 반대방향으로는 Pattern의 크기가 증가하게 된다. 또 이와 같은 운동매질의 영향은 매질속도도가 오고 전류주파수가 높을수록 antenna의 직경이 클수록 더욱 현저하게 된다는 사실을 알게 되었다.

• 한국연초학회지
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• 제26권1호
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• pp.57-63
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• 2004

A comparative analysis of characteristics of domestic and foreign reconstituted tobacco based on papermaking was conducted to evaluate the quality of reconstituted tobacco and to utilize as basic data for improvement of domestic reconstituted tobacco. In the formation, which is key factor to quality and physical properties of product, foreign reconstituted tobacco has better uniform formation than those of domestic one. These result was attributed to distribution of large floc size in the domestic one unevenly. In the fiber morphology, domestic reconstituted tobacco has larger average fiber length and width than those of foreign one. They indicated that fiber morphology of domestic one will exert structural properties of paper such as formation and permeability. Tensile strength of domestic one has lower than those of foreign one by basis weight. In the air permeability, domestic one was remarkably reduced because base web was over sized. It also will affect the combustibility of reconstituted tobacco. In summary, we conclude that the physical and structural properties of domestic reconstituted tobacco result in quality deviations compared with foreign reconstituted tobacco.

• Journal of the Korean Data and Information Science Society
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• 제26권1호
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• pp.197-207
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• 2015

야구경기에서 타자의 능력을 평가하는 중요 측도에는 타율, 타점, 홈런, 득점, 출루율 등이 있지만 최근에는 타자의 능력을 OPS, ISO, SECA, TA, RC, XR 등과 같은 포괄적인 지표를 사용하여 나타내는 경우가 많다. 이러한 지표들은 흔히 특정 기간 동안 얻은 데이터를 이용하여 계산된 것이기 때문에 기간에 따라 대체로 큰 편차를 보이는 경우가 많으며 특정 모수 (parameter)를 추정하는 것도 아니다. 본 연구에서는 한국프로야구 선수들의 순수한 타격 능력 (hitting ability)을 모수로 간주하여 통계적 방법으로 추정하고자한다. 타격 능력에 추정에는 타수 (at bat)가 반영된 베이지안 방법이 사용될 것이다.

• 대한전자공학회논문지
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• 제9권1호
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• pp.17-24
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• 1972

단순한 외부 측정만으로써 수동 및 능동 회로망에서의 한개의 결함요소(Faulty Element)를 결정하기위해서 벡터를 이용한 한 방법을 연구했다. 큰 회로망은 몇개의 작은 회로망이 연결되었다고 생각할 수 있다. 여러 주파수에서의 전달 함수의 크기와 회로요소의 변화와의 사이에서 일어나는 관계를 이용함으로써 Fault Simulation Curve를 그릴 수 있다. 이곡선으로부터 결함식별영역(Fault Identification Region)을 정의한다. 정의된 결함식별영역에 따라 결함시별 매트릭스(Fault Irlentification Matrix)가 형성된다. 어떤 회로로부터 측정된 치를 성분으로하는 벡터를 결함식별 매트릭스에 곱해줌으로써 다른 한개의 벡터를 유도하는데 이유도된 벡터의 성분이 회로의 결함요소를 식별해주는 것이다. 결함식별방법을 위한 한 시험절차가 계시되고 실험에 의하여 입증되었다.

• Nuclear Engineering and Technology
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• 제48권3호
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• pp.820-830
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• 2016

Pipe wall thinning by flow-accelerated corrosion and various types of erosion is a significant and costly damage phenomenon in secondary piping systems of nuclear power plants (NPPs). Most NPPs have management programs to ensure pipe integrity due to wall thinning that includes periodic measurements for pipe wall thicknesses using nondestructive evaluation techniques. Numerous measurements using ultrasonic tests (UTs; one of the nondestructive evaluation technologies) have been performed during scheduled outages in NPPs. Using the thickness measurement data, wall thinning rates of each component are determined conservatively according to several evaluation methods developed by the United States Electric Power Research Institute. However, little is known about the conservativeness or reliability of the evaluation methods because of a lack of understanding of the measurement error. In this study, quantitative models for UT thickness measurement deviations of nuclear pipes and fittings were developed as the first step for establishing an optimized thinning evaluation procedure considering measurement error. In order to understand the characteristics of UT thickness measurement errors of nuclear pipes and fittings, round robin test results, which were obtained by previous researchers under laboratory conditions, were analyzed. Then, based on a large dataset of actual plant data from four NPPs, a quantitative model for UT thickness measurement deviation is proposed for plant conditions.

• 한국정보과학회논문지:데이타베이스
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• 제32권3호
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• pp.228-242
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• 2005

투영 클러스터링은 고 차원 데이타집합에서 서로 다른 부분공간들에서 클러스터들을 찾으려고 모색한다. 사용자가 출력 클러스터들의 개수와 투영 클러스터들의 부분공간의 평균 차원수를 지정하지 않아도, 거의 최적인 투영 클러스터들을 탐사해내는 알고리즘을 제안한다. 클러스터링의 각 단계에서 알고리즘의 목적 함수는 투영 에너지, 품질, 그리고 이상치들의 개수를 계산한다. 클러스터링에서 투영 에너지를 최소화하고 품질을 최대화하기 위하여, 전체 차원의 표준 편차들을 비교함으로 입력 점들의 밀도 상에서 각 클러스터의 최선의 부분영역을 찾기 시작한다. 부분공간의 각 차원에 대한 가중치 요소가 투영 거리 측정에서 확률 오차를 없애기 위하여 사용된다. 제안된 알고리즘이 투영 클러스터들을 정확하게 발견해내고 대 용량의 데이타 집합에서 비례확장성을 갖는다는 것을 여러 가지 실험으로 보여준다.

• 한국연소학회지
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• 제5권1호
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• pp.19-30
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• 2000

The characteristics of NOx emissions in pure hydrogen nonpremixed flames with coaxial air are analyzed numerically for the three model cases of coaxial air flames classified by varying coaxial air velocity and/or fuel velocity. In coaxial air flames, the flame length is reduced by coaxial air and can be represented as a function of the ratio of coaxial air to fuel velocity. Coaxial air decreases flame reaction zone, resulting in reducing flame residence time significantly. Finally, the large reduction of EINOx is achieved by the decrease of the flame residence time. It is found that because coaxial air can break down the flame self-similarity law, appropriate scaling parameters, which are different from those in the simple jet flames, are recommended. In coaxial air flames, the flame residence time based on the flame volume produces better results than that based on a cube of the flame length. And some portion of deviations from the 1/2 scaling law by coaxial air may be due to the violation of the linear relationship between the flame volume and the flame reaction zone.

• 품질경영학회지
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• 제38권3호
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• pp.313-321
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• 2010

The coefficient of variation represents the ratio of the standard deviation to the mean, and it is a useful statistic for comparing the degree of variation from one data series to another, even if the means are drastically different from each other. Recently, the CV control chart is developed for monitoring processes in such situations. However, the CV control chart has low performance in detecting small shift. Due to the development of equipment and technique, currently, small shift of process occurs more frequently than large shift. In this paper, we proposes the CV-CUSUM control chart using CUSUM scheme which is cumulative sum of the deviations between each data point and a target value to detect a small shift in the process. We also found that the FIR(fast initial response) CUSUM control chart is especially valuable at start-up or after a CV-CUSUM control chart has signaled out-of-control.