• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.425-429
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• 1987

This paper describes a collision avoidance method for planning safe trajectories for multi-robot system in common work space. Usually objects have been approximated to convex polyhedra in most previous researches, but in case using such the approximation method it is difficult to represent objects analytically in terms of functions and also to describe tile relationship between the objects. In this paper, in order to solve such problems a modeling method which approximates objects to cylinder ended by hemispheres and or sphere is used and the maximum distance functions is defined which call be calculated simply. Using an objective function with inequality constraints which are related to minimum distance functions, work range and maximum allowable angular velocities of the robots, tile collision avoidance for two robots is formulated to a constrained function optimization problem. With a view to solve tile problem a penalty function having simple form is defined and used. A simple numerical example involving two PUMA-type robots is described.

• 대한수학회지
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• 제33권2호
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• pp.259-268
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• 1996

The Data Encryption Standard(DES) [3, 8, 9] was developed by an IBM team aroung 1974 and adopted as a national standard in 1977.

• 디지털융복합연구
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• 제12권8호
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• pp.321-327
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• 2014

특징 선택은 중복 또는 서로간의 관련이 없는 특징을 제거하여 분류 성능을 향상시키는 기술이다. 본 논문에서는 가중 퍼지소속함수 기반 신경망 (Neural Network with Weighted Fuzzy Membership Functions; NEWFM)에서 제공하는 가중 퍼지소속함수의 경계합 (Bounded Sum of Weighted Fuzzy Membership functions, BSWFM)의 무게중심간의 거리를 이용한 새로운 특징 선택을 제안하여 분류 성능을 향상시켰다. 이러한 거리 기반의 특징 선택을 이용하여 초기 24개의 특징으로부터 무게중심간의 거리가 짧은 특징을 하나씩 제거되면서 분류 성능이 가능 높은 22개의 최소 특징을 선택하였다. 이들 22개의 최소 특징을 NEWFM의 입력으로 사용하여 97.7%, 99.7%, 98.7%의 민감도, 특이도, 정확도를 각각 구하였다.

• 응용통계연구
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• 제25권6호
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• pp.1009-1018
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• 2012

Persistence homology (a type of methodology in computational algebraic topology) can be used to capture the topological characteristics of functional data. To visualize the characteristics, a persistence diagram is adopted by plotting baseline and the pairs that consist of local minimum and local maximum. We use the bottleneck distance to measure the topological distance between two different functions; in addition, this distance can be applied to multidimensional scaling(MDS) that visualizes the imaginary position based on the distance between functions. In this study, we use handwriting data (which has functional forms) to get persistence diagram and check differences between the observations by using bottleneck distance and the MDS.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제19권4호
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• pp.337-347
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• 2012

The taxicab distance and Chinese-checker distance in the plane are practical distance notions with a wide range of applications compared to the Euclidean distance. The ${\alpha}$-distance was introduced as a generalization of these two distance functions. In this paper, we study alpha circle, trigonometry, and the area of a triangle in the plane with ${\alpha}$-distance.

• 정보교육학회논문지
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• 제1권2호
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• pp.67-83
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• 1997

We studied a CAI courseware model for distance education on network, with the use of Java language. Basic www files, contents of courseware, are constructed with html. Students and educator can access the preferred unit composed of the appropriate multimedia data by using of www browser at any time. The distance education system, in this paper, has functions to manage the flow of distance learning, and to offer interaction between students and system in distributed environment. Students and/or 'educator can discuss a topic through server in different places. We implemented these functions, which are required in server and client environment of distance education, with the use of Java.

• 정보교육학회논문지
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• 제3권2호
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• pp.113-119
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• 2000

I studied a distance education model for English learning on the Internet. Basic WWW files, that contain courseware, are constructed with HTML, and functions, which are required in learning, are implemented with Java. Students and educators can access the preferred unit composed of the appropriate text, voice and image data by using a WWW browser at any time. The education system supports the automatic generation facility of English problems to practice reading and writing by making good use of the courseware data or various English text resources located on the Internet. Our system has functions to manage and control the flow of distance learning and to offer interaction between students and the system in a distributed environment. Educators can manage students' learning and can immediately be aware of who is attending and who is quitting the lesson in virtual space. Also, students and educators in different places can communicate and discuss a topic through the server. I implemented these functions, which are required in a client/server environment of distance education, with the use of Java. The URL for this system is "http://park.taegu-e.ac.kr" in the name of GAIA.

• Journal of Communications and Networks
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• 제12권5호
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• pp.399-405
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• 2010

Blind equalization techniques have been used in broadcast and multipoint communications. In this paper, two criteria of minimizing Euclidian distance between two probability density functions (PDFs) for adaptive blind equalizers are presented. For PDF calculation, Parzen window estimator is used. One criterion is to use a set of randomly generated desired symbols at the receiver so that PDF of the generated symbols matches that of the transmitted symbols. The second method is to use a set of Dirac delta functions in place of the PDF of the transmitted symbols. From the simulation results, the proposed methods significantly outperform the constant modulus algorithm in multipath channel environments.

• Communications for Statistical Applications and Methods
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• 제31권5호
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• pp.601-612
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• 2024

A functional clustering analysis is a crucial machine learning technique in functional data analysis. Many functional clustering methods have been developed to enhance clustering performance. Moreover, due to the phase variability between functions, elastic functional clustering methods, such as applying the Fisher-Rao metric, which can manage phase variation during clustering, have been developed to improve model performance. However, aligning functions without considering the phase variation can distort functional information because phase variation can be a natural characteristic of functions. Hence, we propose a state-of-the-art functional hierarchical clustering that can manage phase and amplitude variations of functional data. This approach is based on the phase and amplitude separation method using the norm-preserving time warping of functions. Due to its invariance property, this representation provides robust variability for phase and amplitude components of functions and improves clustering performance compared to conventional functional hierarchical clustering models. We demonstrate this framework using simulated and real data.

• 한국정보통신학회논문지
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• 제21권6호
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• pp.1237-1242
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• 2017

컴퓨터 비전은 인공 지능 기술을 통해 인간의 시각 시스템을 모방해 주변 환경을 보다 정확하게 인식하는 새로운 이미지 센서 기능으로 각광받고 있다. 본 논문에서는 사물감지 및 거리측정 기능이 있는 새로운 깊이 센서인 키넥트(Kinect) 카메라를 통해, 무인 또는 유인 차량, 로봇 및 드론 등을 위한 컴퓨터 비전의 가장 중요한 기능들을 대상으로 시험을 진행하였다. 키넥트 카메라를 통해 시야 내에 있는 사물의 자리 또는 위치를 예측하고, 실제 사물이 아닌 픽셀을 무시해 처리 시간을 줄일 수 있도록 감지한 사물이 실제 사물인지 확인하여 깊이 센터를 통해 정확하게 거리를 측정한다. 실험 결과, 해당 거리센서는 좋은 결과를 나타냈으며, 추가 프로세싱을 위한 컴퓨터 비전 어플리케이션의 핵심 기능인 사물감지와 거리측정에 키넥트 카메라를 사용한다.