• East Asian mathematical journal
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• 제27권5호
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• pp.557-564
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• 2011

In 2007, Huang and Zhang [1] introduced a cone metric space with a cone metric generalizing the usual metric space by replacing the real numbers with Banach space ordered by the cone. They considered some fixed point theorems for contractive mappings in cone metric spaces. Since then, the fixed point theory for mappings in cone metric spaces has become a subject of interest in [1-6] and references therein. In this paper, we consider some fixed point theorems for generalized nonexpansive setvalued mappings under suitable conditions in sequentially compact cone metric spaces and complete cone metric spaces.

• Communications for Statistical Applications and Methods
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• 제3권2호
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• pp.175-185
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• 1996

For the Change-point problem in a sequence of binomial variables we consider the maximum likelihood estimator (MLE) of unknown change-point. Its asymptotic distribution is quite limited in the case of binomial variables with different numver of trials at each time point. Hinkley and Hinkley (1970) gives an asymptotic distribution of the MLE for a sequence of Bernoulli random variables. To find the asymptotic distribution a numerical method such as bootstrap can be used. Another concern of our interest in the inference on the change-point and we derive confidence sets based on the liklihood ratio test(LRT). We find approximate confidence sets from the bootstrap distribution and compare the two results through an example.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2002년도 춘계 학술발표회 논문집
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• pp.1-5
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• 2002

We consider the problem of optimal bandwidth choice for nonparametric classification, based on kernel density estimators, where the problem of interest is distinguishing between two univariate distributions. When the densities intersect at a single point, optimal bandwidth choice depends on curvatures of the densities at that point. The problem of empirical bandwidth selection and classifying data in the tails of a distribution are also addressed.

• 품질경영학회지
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• 제30권4호
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• pp.78-85
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• 2002

The problem of trend change in the mean residual life is great interest in the reliability and survival analysis. In this paper, a new test statistic for testing whether or not the mean residual life changes its trend is developed. It is assumed that neither the change point nor the proportion at which the trend change occurs is known. The asymptotic null distribution of test statistic is established and asymptotic critical values of the asymptotic null distribution is obtained. Monte Carlo simulation is used to compare the proposed test with previously known tests.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.673-676
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• 2003

This paper deals with the problem of moving object detection and location in computer vision. We describe a new object-dependent motion analysis method for tracking target in an image sequence taken from a moving platform. We tackle these tasks with three steps. First, we make an active contour model of a target in order to build some of low-energy points, which are called kernels. Then we detect interest points in two windows called tracking windows around a kernel respectively. At the third step, we decide the correspondence of those detected interest points between tracking windows by the probabilistic relaxation method In this algorithm, the detecting process is iterative and begins with the detection of all potential correspondence pair in consecutive image. Each pair of corresponding points is then iteratively recomputed to get a globally optimum set of pairwise correspondences.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.93-93
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• 2003

Tungsten and tungsten heavy alloys have widespread application as radiation shielding devices and heavy duty electrical contacts. High density and good room temperature mechanical properties have generated interest in evaluating tungsten and tungsten alloys as kinetic energy penetrators against armor. Nowdays ultra fine-grained tungsten powders are in great interest because higly dense structures can be obtained at low temperature, pressure and lower sintering time. Several physical md chemical methods are available for the synthesis of nanometric metal Powders: ball milling, laser abalation, vapor condensation, chemical precipitation, metallic wire explosion i.e. However production rates of the above mentioned methods are low and further efforts are needed to find out large-scale synthesis methods. From this point of view solid state combustion method ( known as SHS) represents undoubted interest.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제20권12호
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• pp.652-657
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• 2014

출발지와 도착지, 사용자가 방문해야 하는 POI(Point of Interest)유형들, 이 유형들 중 전체 혹은 부분에 대한 방문순서들이 주어질 때, 출발지에서 여러 방문순서를 만족시키는 순서대로 각 POI 유형별로 적어도 하나의 POI를 방문한 후 목적지에 도착하는 경로를 순차적 경로라 한다. 본 논문에선 이 경로 중 근사 최단 경로(Approximate Shortest Path)를 찾는다. 기존의 두 가지 기법은 방문한 POI(또는 출발지)와 방문해야 할 유형의 POI들과의 근접성 만을 보거나 후보군 선정 시 방문순서 및 네트워크를 고려하지 않고 출발지와 목적지를 이은 직선과 가까운 POI들로 경로를 찾는 문제를 갖고 있었다. 본 논문에서는 네트워크 탐색을 이용하여 출발지와 목적지 간 네트워크 경로에 근접한 POI를 후보군으로 선정하여 경로를 탐색하고, 이 경로 중 방문한 POI유형이 많은 경로에 적응적 우선순위를 주어 향상된 근사 최단 경로를 구하는 기법을 제안한다.

• 대한원격탐사학회지
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• 제16권4호
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• pp.355-365
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• 2000

The interferometric correlation, or coherence, is calculated to measure the variance of the interferometric phase and amplitude within the neighbourhood of any location within the image at a result of SAR (Synthetic Aperture Radar) interferometric process which utilizes the phase information of the images. The coherence contains additional information that is useful for detecting point targets which change their location in an area of interest (AOI). In this research, a RGB colour composite image was generated with a intensity image (master image), a intensity change image as a difference between master image and slave image, and a coherence image generated as a part of SAR interferometric processing. We developed a technique performing detection of a point target movement using SAR interferometry and applied it to suitable tandem pair images of ERS-1 and ERS-2 as test data. The possibility of change detection of a point target in the AOI could be identified with the technique proposed in this research.

• Communications for Statistical Applications and Methods
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• 제28권5호
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• pp.511-520
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• 2021

Over the last decade, Bitcoin has attracted a great deal of public interest and Bitcoin market has grown rapidly. One of the main characteristics of the market is that it often undergoes some events or incidents that cause outlying observations. To obtain reliable results in the statistical analysis of Bitcoin data, these outlying observations need to be carefully treated. In this study, we are interested in change point analysis for Bitcoin return series having such outlying observations. Since these outlying observations can affect change point analysis undesirably, we use a robust test for parameter change to locate change points. We report some significant change points that are not detected by the existing tests and demonstrate that the model allowing for parameter changes is better fitted to the data. Finally, we show that the model with parameter change can improve the forecasting performance of Value-at-Risk.

• 한국시뮬레이션학회논문지
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• 제27권2호
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• pp.1-10
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• 2018

본 논문은 지상무인전투체계 중의 하나인 무인경전투차량이 RGB 영상정보를 기초로 스스로 전차를 탐지하고 조준점을 산출하는 지능형 표적획득/처리기술의 기초연구이다. 무인 경전투 차량이 전장에서 적 전차와 조우 시, 적 전차를 자율적으로 탐지하고 스스로 조준하는 방법을 개발하기 위해, 영상정보로부터 전차의 주요특징을 식별 및 추출하고, Maximally stable extremal regions, 중간값 필터, k평균 클러스터링 그리고 Morphological filtering의 영상처리기법 및 인공지능 알고리즘을 통해 전차의 외형정보를 추출 및 분석하였으며, 식별된 전차 외형정보를 벡터화하여 전차의 중앙을 지향하는 조준점을 산출하였다. 또한, 본 연구의 성능을 측정하기 위해 선진국들의 주력전차의 영상정보를 수집 및 분석하였고, 제안한 방법의 객관적인 전차탐지 성능은 정확도 91.6%, 정밀도 90.4%, 재현율 85.8% 그리고 F-measure 88.1%의 결과를 보여주었다. 본 연구가 무인전투체계의 지능형 표적획득/처리기술 연구개발에 도움이 되기를 기대한다.