고장시간 분포 추정을 위한 단일화된 접근 방법

김동석,윤복식,양경아 弘益大學校 科學技術硏究所 1996 科學技術硏究論文集 Vol.7 No.1

In this paper, we propose a simple and effective life distribution model based on piecewise Weibull failure rate function, called PWF model and introduce a simple method to estimate the parameters in PWF model based on the sequential partial F test and the least square method. All the procedures are computer coded and various numerical application exmples are also given. The results in this paper can be used to analyze failure time data almost automatically under quite general environment.

第2次 잭나이프를 이용한 密度函數 推定

姜錫福 嶺南大學校 基礎科學硏究所 1991 基礎科學硏究 Vol.11 No.-

In this paper, we propose Sharot's family of jackknives which include the first and second order jackknives as a special cases and the generalized second order jackknife estimator as the density estimator. The numerical values of the mean integrated square errors of the proposed jackknife estimators are obtained for some special cases. The proposed generalized second order jackknife estimator is shown to be preferable in the small sample size.

수명 검사 자료의 분석 방법에 관한 연구

윤복식,김동석 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.5 No.-

Life testing data has some peculiar features which can be utilized for proper statistical analysis. Among others it has the bathtub curve describing the change of the failure rate according to the elapsed time. In this paper, we review various efforts to get life distributions fitted for the bathtub-like failure rate function and propose simple and effective life distribution models based on piecewise Weibull failure rate function. Also, we introduce a simple method to estimate the failure rate of the censored life testing data. We can utilize the results in this paper to develop a comprehensive computational tool for reliability analysis.

일본의 중심시가지 활성화에 관한 동향

윤상복,윤시운,오석기,이종식 동아대학교 건설기술연구소 1999 硏究報告 Vol.23 No.2

Currently, Suburbanization of commercial function in local and metropolitan city of Japan brought about doughnut phenomenon of city center, which made it seriously devastated. This study aims at the grasp of the depressed phenomenon caused by doughnut, providing a fundamental guide for activation of the central city in Korea through analysis of trends and strategy about it in Japan.

극단값分布의 母數에 대한 붓스트랩 推定

姜錫福,趙容德 嶺南大學校 基礎科學硏究所 1996 基礎科學硏究 Vol.16 No.-

We propose the estimators of the parameters of the extreme value distribution when the scale parameter is known and unknown. We compare the proposed estimators of the parameters with the maximum likelihood estimator (MLE) in the extreme value distribution in the sense of mean square errors (MSE) through Monte Carlo method.

데이타 네트워크에 있어서 경로 선택 알고리즘에 관한 연구

조정복,이재욱,임효택,고석범 東西大學校 1998 동서논문집 Vol.4 No.-

최근에 많은 기업체에서 LAN(Local Area Network)을 기반으로 하는 인터넷 환경을 구축하는 예가 종종 보고되어 지는 것을 보면 네트워크 설계분야에 많은 관심이 집중되고 있음을 알 수 있다. 본 논문에서, Star-Ring LAN상에서 HUB의 할당과 경로 선택 문제를 취급한다. Star-Ring LAN의 설계는 1)HUB들과 사용자 노드(컴퓨터)들 간의 연결, 2)HUB들 간의 경로 선택 문제로 나눌 수 있다. 여기서 제안한 수학적 모델은 HUB의 설치 비용과 각 노드에서 트래픽의 전송 지연 시간을 고려한다. 그리고 최적 해를 탐색하기 위하여 경험적 탐색방법의 하나인 유전 알고리즘(GA:Genetic Algorithm)을 설계한다. 끝으로 본 논문에서 제안된 유전 알고리즘의 성능을 검증하기 위하여 하나의 수치 예를 보인다. Recently, many people are interested in the field of network design again as we know that Intranet environment based on LAN(Local Area Network) is often implemented at many companies. In this paper, we deal with the HUB allocation and routing problem on Star-Ring LAN. The design of Star-Ring LAN is divided into two level problems: 1)connecting between HUBs and user nodes(i.e. computers), and 2) routing between HUBs. In the mathematical model which we will develope, the cost to set up HUBs, and delay time due to communication traffic at each node should be considered as the important factors. Also, we investigate GA(genetic Algorithm)as heuristic method to search the optimal solution. Lastly, we show a numerical example to demonstrate good performances of the proposed method.

두경부 유리피판 26례 분석

정복성,윤근철,심경보,고경석,한상훈 大韓成形外科學會 1993 Archives of Plastic Surgery Vol.20 No.3

Twenty four patients(21 males and 3 females) aged 14 to 70 years underwent 26 microvascular free tissue transfers in head and neck reconstructions from April 1990 to July 1992 (27 months) . Nineteen cases were tumors in head and neck area, and four were acquired deformities such as burn alopecia, burn scar contracture of the neck, Romberg disease and frontal sinus infection, and one was hemifaclal microsomia. The free flaps were executed successfully in 15 upper aerodigestive tracts, in 2 scalps and 3 skull bases and in contouring and resurfacing six facial and cervical lesions. The selection of donor site was bases upon the location of defect and the volume of tissue required : the forearm free flap was used in 11 cases, the rectus abdominis in 5, the groin in 2, the jejunum in 2, the occipital scalp in one, the first toe web space in one, the latissimus dorsi in one, the serratus anterior in one, the parietotemporalis fascia in one and the omentum in one. The free tissue transfers were primarily indicated in all patients in our series and there was no flap failure. The complications were minimal and the morbidities low. A free flap in the head and neck area is not only the most expedient method of reconstruction but also either the most reliable or the only available one in some clinical situations.

사회문제 중심의 지역화 교재구성의 실제 : 울산지역을 중심으로 in the case of Ulsan

이기복,성숙희 부산교육대학교 교육대학원 2001 논문집 Vol.3 No.-

The goal of this study is to introduce regional social problems that might embody the essence of region in the social curriculum at elementary school social studies, to constitute learning material in an integrated way, and to embody a proper teaching model. In order to reach this goal, first, this study provides a standard that refers to general theoretical research about region and social problems and principles and method in text composition. Second, this study abstracts social problems relating to the Ulsan region and classifies their features for the development of integrated teaching material for inter-studies. Third, this study embodies the teaching-learning model of the social studies curriculum at the heart of the content of the text and tries to apply it to the school classroom environment. Especially, in order to make teaching material that addresses key social problems of the region, this study divides social problems in the Ulsan region into problems of social organization, social disorganization, and deviation, and divides them again into the following problem types: economic, regional gap, city, environmental, home, and crime. Furthermore, it suggests a procedure for text composition and clearly shows, as related constituents, the key idea, the goals, the teaching-learning process, and the assignment. It takes into account Learner's development of social consciousness and experiential Level as much as possible.

冪函數 分布의 로렌쯔 曲線과 지니 指數의 推定

姜錫福,趙瑛錫 嶺南大學校 基礎科學硏究所 1991 基礎科學硏究 Vol.11 No.-

In this paper, we obtain the maximum likelihood estimator, the uniformly minimum variance unbiased estimator and a strongly consistent asymptotically normal unbiased estimator for each of Lorenz curve and Gini index of a power function distribution. The mean square error of each estimator is derived in terms of several special functions. The unmerical values of the mean square errors are also obtained.

정규화한 표본 로렌츠 곡선의 성질

강석복,유세기 嶺南大學校基礎科學硏究所 2002 基礎科學硏究 Vol.22 No.-

In this paper, we prove that the transformed sample Lorenz curve, normalized sample Lorenz curve, and the test statistics for testing of normality based on the normalized sample Lorenz curve and the modified Lorenz curve which were introduced by Kang and Cho (2001a, 2002) are location and scale invariant statistics.