• 제목/요약/키워드: Change points

검색결과 1,782건 처리시간 0.029초

Bayesian Multiple Change-Point Estimation of Multivariate Mean Vectors for Small Data

  • Cheon, Sooyoung;Yu, Wenxing
    • 응용통계연구
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    • 제25권6호
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    • pp.999-1008
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    • 2012
  • A Bayesian multiple change-point model for small data is proposed for multivariate means and is an extension of the univariate case of Cheon and Yu (2012). The proposed model requires data from a multivariate noncentral $t$-distribution and conjugate priors for the distributional parameters. We apply the Metropolis-Hastings-within-Gibbs Sampling algorithm to the proposed model to detecte multiple change-points. The performance of our proposed algorithm has been investigated on simulated and real dataset, Hanwoo fat content bivariate data.

Application of Change Detection Techniques Using KOMPSAT-1 EOC Images

  • Kim, Youn-Soo;Lee, Kwang-Jae
    • 대한원격탐사학회지
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    • 제19권3호
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    • pp.263-269
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    • 2003
  • This research examined the capabilities of KOMPSAT-1 EOC images for the application of urban environment, including the urban changes of the study areas. This research is constructed in three stages: Firstly, for the application of change detection techniques, which utilizes multi-temporal remotely sensed data, the data normalization process is carried out. Secondly, the change detection method is applied for the systematic monitoring of land-use changes. Lastly, using the results of the previous stages, the land-use map is updated. Consequently, the patterns of land-use changes are monitored by the proposed scheme. In this research, using the multi-temporal KOMPSAT-1 EOC images and land-use maps, monitoring of urban growth was carried out with the application of land-use changes, and the potential and scope of the application of the EOC images were also examined.

심근허혈 진단을 위한 ST세그먼트 형태 분류 알고리즘 (ST Segment Shape Classification Algorithm for Making Diagnosis of Myocardial Ischemia)

  • 조익성;권혁숭
    • 한국정보통신학회논문지
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    • 제15권10호
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    • pp.2223-2230
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    • 2011
  • 심전도는 심근허혈, 부정맥, 심근경색과 같은 심장질환의 진단에 이용된다. 특히 심근허혈은 ST 세그먼트의 형태 변화가 나타나는데, 이러한 변화는 일시적으로 나타나며 특별한 증상을 동반하지 않는다. 따라서 지속적인 모니터링을 통해서 ST의 일시적인 변화를 검출하는 것이 매우 중요하다. 이에 본 연구에서는 심근허혈 진단을 위한 ST세그먼트 형태 분류 알고리즘을 제안한다. 이는 전처리 과정과 적응가변형 문턱치를 통해 R파와 각 특징점을 검출 한 후 S와 T파사이의 굴곡점으로부터 특정한 기울기 정보를 추출하여 ST의 기울기 기준점과 비교함으로써, 검출된 ST를 6가지 형태로 분류하는 방법이다. 개발된 알고리즘은 심전도로부터 ST 레벨 변화 구간을 검출하고, 검출된 구간에 대해서도 ST의 형태를 분류함으로써 심전도 레벨 변화뿐만 아니라 형태에 대한 정보도 제공한다. 제안한 알고리즘의 심근허혈 패턴 진단 성능을 평가하기 위해서 European ST 데이터베이스를 사용하였다. 성능 평가 결과 가장 높은 분류성공률은 99.4%이며, 낮은 성공률은 68.48%를 나타내었다.

상지동작에 따른 길의 변화에 관한 연구(제2보) - 사선방향의 변화를 중심으로 - (A Study on the Change of Waist Pattern by Upper Limb Motion (Part 2) - By the Change of Oblique Line -)

  • 이은정
    • 한국의류산업학회지
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    • 제4권2호
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    • pp.145-155
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    • 2002
  • In order to investigate how upper limb motion gives influence on clothing, this study measured tests by following standards: Front Vertical motion, Side-Vertical motion, and Horizontal motion. For this study, the procedures in the order of alphabet are applied. A. Eeach of testee's pattern was copied by the motion with a method of tight fitting technique. B. Analyzing each of the size-change on measuring item. C. Studying the moving aspects at each datum points. The results shows that the biggest change can be found in the following items. 1) In vertical motion of F4 (the length to shoulder point from A-point) 2) In horizontal motion of F5 (the length to front-width point from A-point), the check-result gained by checking the notice between motions shows that the most noticeable items are F4 (the length to shoulder point from A-point), F5 (the length to front-width point from A-point), F6 (the length to armpit point from A-point), B7 (the length to side-waist point from B-point). In result of the study of datum point's movement by motion, the items which were measured with the longest on straight-distance in vertical motion are the front and rear-shoulder, and the rear-shoulder, front-armpit in horizontal motion each. In the movement of each datum points by length, the check-result gained by checking the notice between motions shows that the most remarkable item is the front-shoulder.

불확실성을 고려한 미래 잣나무의 서식 적지 분포 예측 - 종 분포 모형과 RCP시나리오를 중심으로 - (Estimating Korean Pine(Pinus koraiensis) Habitat Distribution Considering Climate Change Uncertainty - Using Species Distribution Models and RCP Scenarios -)

  • 안윤정;이동근;김호걸;박찬;김지연;김재욱
    • 한국환경복원기술학회지
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    • 제18권3호
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    • pp.51-64
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    • 2015
  • Climate change will make significant impact on species distribution in forest. Pinus koraiensis which is commonly called as Korean Pine is normally distributed in frigid zones. Climate change which causes severe heat could affect distribution of Korean pine. Therefore, this study predicted the distribution of Korean Pine and the suitable habitat area with consideration on uncertainty by applying climate change scenarios on an ensemble model. First of all, a site index was considered when selecting present and absent points and a stratified method was used to select the points. Secondly, environmental and climate variables were chosen by literature review and then confirmed with experts. Those variables were used as input data of BIOMOD2. Thirdly, the present distribution model was made. The result was validated with ROC. Lastly, RCP scenarios were applied on the models to create the future distribution model. As a results, each individual model shows quite big differences in the results but generally most models and ensemble models estimated that the suitable habitat area would be decreased in midterm future(40s) as well as long term future(90s).

한말 충청수영 객사·동헌의 위치와 존치상태 연구 (A Study on the Position and Preservation Situation of Gaeksa·Dongheon in Choongcheong Suyeong at the end Joseon Dynasty)

  • 김명래
    • 건축역사연구
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    • 제27권2호
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    • pp.101-112
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    • 2018
  • The study on the government office building in Chungcheong Suyeong(忠淸水營) is very rare. How were the Gaeksa(客舍) and Dongheon(東軒) which are representative government office buildings in Suyeong, maintained and what was the aspect of it, while passing through the upheaval period of the end of Joseon(朝鮮)? And where was the original place and was there any change in use? It is so regrettable that these subjects were not figured out yet. So I thought it is very important task to figure out its actual aspect by investigating the maintain state of the Gaeksa and Dongheon and the change of their places. So this study examined the related historical records and, based on it, analyzed "Ocheon GoonJi(鰲川郡誌)" in various view points. Through this analysis, this study could figured out the maintain aspect of the gaeksa and dongheon and the change of their places, and be able to deduce the other change of the government office building. This study could assume the places of each government office buildings by comparing this investigated result and the analyzed result of the original cadastral map in various view points. As the result of the study done by this method, this study confirmed the maintain state of the Gaeksa and Dongheon in Chungcheong Suyeong while passing through the upheaval period of the end of Joseon. And this study figured out the places of the Gaeksa and Dongheon, and be able to confirm their places by the lot number on the original cadastral map. Along with this, this study could estimate Jo(趙) family's confliction with the residents at that time by verifying the lot numbers of the Sapaeji(賜牌地) which this family received from the government. And among the names of the government office buildings, for the Jangkyocheong(將校廳) which is in dispute because of the name, this study figured out that the author of "Ocheon GoonJi" made a mistake in writing Dongheon.

광량 변화에 강건한 가중치 국부 기술자 기반의 스테레오 정합 (Robust Stereo Matching under Radiometric Change based on Weighted Local Descriptor)

  • 구자민;김용호;이상근
    • 전자공학회논문지
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    • 제52권4호
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    • pp.164-174
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    • 2015
  • 기하학적 특성이 주어진 두 개 이상의 카메라를 사용하거나 한 개의 카메라를 이동시켜가면서 스테레오 영상을 얻을 때에, 카메라 설정 값의 차이, 조명의 변화 등으로 인해 광량의 변화가 발생한다. 하지만 색상 유사도를 기반으로 한 기존의 스테레오 정합 방법들은 정확한 대응점을 추정하지 못한다. 본 논문에서는 광량 변화에 강건하기 위한 방법으로 스테레오 영상에서 픽셀의 밝기 정보와 그라디언트 정보 및 텍스쳐 정보를 국부 기술자로 구성하는 새로운 방법을 제안하고, 엔트로피에 기반한 적응적 가중치를 국부 기술자에 부여하여 광량 변화에도 정확한 대응점을 추정할 수 있도록 한다. 제안하는 방법은 조명의 변화, 노출 시간의 차이로 인해 광량 변화가 발생된 Middlebury의 실험 영상을 통해 실험되었으며, 광량 변화에 강건한 최근의 방법들과 비교하였다. 그 결과, 제안하는 방법은 전체 영역에서의 오정합 비율이 약 5 % 정도로 비교하는 방법들보다 낮게 발생하여 가장 좋은 성능을 보여주었다.

전이학습 기법을 이용한 철도교량의 동적응답 예측 (Predicting Dynamic Response of a Railway Bridge Using Transfer-Learning Technique)

  • 김민수;최상현
    • 한국전산구조공학회논문집
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    • 제36권1호
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    • pp.39-48
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    • 2023
  • 철도교량의 설계는 장기간에 걸쳐 수행되고 대규모의 부지를 대상으로 하기 때문에 다양한 환경적인 요인과 불확실성을 동반하게 된다. 이러한 연유로 초기 설계단계에서 충분히 검토하였더라도 설계변경이 종종 발생하고 있다. 특히 철도교량과 같은 대규모 시설물의 설계변경은 많은 시간과 인력을 소모하며, 매번 모든 절차를 반복하는 것은 매우 비효율적이다. 본 연구에서는 딥러닝 알고리즘 중 전이학습을 통해 설계변경 전의 학습 결과를 활용하여 설계변경 후의 학습의 효율성을 향상시킬 수 있는 기법을 제안하였다. 분석을 위해 기개발한 철도교량 딥러닝 기반 예측 시스템을 활용하여 시나리오들을 작성하고 데이터베이스를 구축하였다. 제안된 기법은 설계변경 전 기존 도메인에서 학습에 사용한 8,000개의 학습데이터 대비 새로운 도메인에서 1,000개의 데이터만을 학습하여 유사한 정확도를 나타내었고 보다 빠른 수렴속도를 가지는 것을 확인하였다.

Some Nonparametric Tests for Change-points with Epidemic Alternatives

  • Kim, Kyung-Moo
    • Communications for Statistical Applications and Methods
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    • 제4권2호
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    • pp.427-434
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    • 1997
  • The purpose of this paper is to discuss distribution-free tests of hypothesis that the random samples are identically distributed against the epidemic alternative. But most tests that have been considered are depended only on specific null distribution. Two nonparametric tests are considered and compared with a likelihood ratio test by the empirical powers.

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학교보건교사 전염병관리교육 효과평가 (Evaluation of Field Epidemiology Specialist Program for School Nurse)

  • 박노례;권준욱;김명순;정인숙
    • 보건교육건강증진학회지
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    • 제24권1호
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    • pp.63-74
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    • 2007
  • Objectives: This study aimed to evaluate the educational effect of the Field Epidemiology Specialist Training Program for School Nurse which composed of 18hours curriculum. Method: The subjects were 797 who participated in the 2005 training program. Data was collected with structured questionnaires(knowledge on the control of communicable disease 15 items, attitude 15 items, and confidence in practice 14 items, demographic characteristics 4 items) before (January) and after (July to October) programs in 2005. Results: Knowledge on the control of communicable disease was improved from 9.7 points (possible range : 0-15) before program to 11.9 points after program. Attitude was improved from 53.6 points (possible range : 15-60) before program to 55.7 points after program. Confidence in practice was changed from 45.9 points (possible range : 14-56) before program to 50.0 points after program. Even though all three areas were improved after educational program, knowledge showed the largest change among them. Conclusion: We can conclude the educational program was effective because knowledge, attitude, and confidence in practice on the control of communicable were statistically significantly improved after educational program. Further educational program is recommended to be operated to get more improvement in attitude and confidence in practice. And short-term continuing educational program is needed to maintain and refresh the information on the control of communicable diseases in schools.