• 한국음향학회지
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• 제20권2호
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• pp.10-15
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• 2001

본 논문에서 우리는 음향신호에서 음성과 음악을 분류하는 음성/음악 분류실험에 사용되는 특징들간의 상호조합을 비교하였다. 음향신호는 3가지 (음성, 음악, 음성+음악)와 2가지 (음성, 음악)로 분류하였다. 실험은 멜캡스트럼, 에너지, 영교차를 특징으로 사용하였고, 음성/음악 분류성능이 가장 좋은 특징간 상호조합을 모색하였다. 분류 알고리즘으로는 Gaussian Mixture Model (GMM)을 이용하였으며, GMM에 의한 데이터 모델링 전에 각기 다른 특징들을 하나의 특징공간에서 결합하였다. 실험결과 3가지 분류기준 적용시에는 멜캡스트럼, 영교차 조합이 가장 좋은 결과 (음성: 95.1％, 음악: 61.9％, 음성+음악: 55.5％)를 보였고, 2가지 분류기준 적용시에는 멜캡스트럼, 에너지 조합과 멜캡스트럼, 에너지, 영교차 조합이 가장 좋은 결과 (음성: 98.9％, 음악: 100％)를 보였다.

• Korean Journal of Mathematics
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• 제27권1호
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• pp.9-15
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• 2019

In this paper, we study a type of Riemannian manifold, namely quasi Ricci symmetric manifold. Among others, we show that the scalar curvature of a quasi Ricci symmetric manifold is constant. In addition if the manifold is Einstein, then its Ricci tensor is zero. Also we prove that if the associated vector field of a quasi Ricci symmetric manifold is either recurrent or concurrent, then its Ricci tensor is zero.

• 한국멀티미디어학회논문지
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• 제17권7호
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• pp.769-777
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• 2014

With the rapid interest in Geographic Information System (GIS) contents, a large volume of valuable GIS dataset has been distributed illegally by pirates, hackers, or unauthorized users. Therefore the problem focus on how to protect the copyright of GIS vector map data for storage and transmission. At this point, GIS security techniques focusing on secure network and data encryption have been studied and developed to solve the copyright protection and illegal copy prevention for GIS digital map. But GIS vector map data is very large and current data encryption techniques often encrypt all components of data. That means we have encrypted large amount of data lead to the long encrypting time and high complexity computation. This paper presents a novel selective encryption scheme for GIS vector map data protection to store, transmit or distribute to authorized users using K-means algorithm. The proposed algorithm only encrypts a small part of data based on properties of polylines and polygons in GIS vector map but it can change whole data of GIS vector map. Experimental results verified the proposed algorithm effectively and error in decryption is approximately zero.

• 한국경영과학회지
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• 제6권2호
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• pp.21-23
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• 1981

It is known that two-person zero-sum game with vector payoff can be reduced to a multiple objective linear programming. However, in this case, solutions for the game nay not be one, but many, In many cases in reality, one may need only one solution rather than all solutions. This paper develops a method to find a practical solution for the game by linear programming.

• Architectural research
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• 제14권4호
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• pp.143-152
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• 2012

A form-finding procedure is presented for planar tensegrity structures. Notably, a simple decision criteria is proposed to select the desirable candidate position vector from the unitary matrix produced by the eigenvalue decomposition of force density matrix. The soundness of the candidate position vector guarantees faster convergence and produces a desirable form of tensegrity without any member having zero-length. Several numerical examples are provided to demonstrate the capability of the proposed form-finding process.

• 한국경영과학회지
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• 제10권2호
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• pp.28-37
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• 1985

An obvious of ESACF approach for model identification by Tsay and Tiao(1984) is that the user may be confused by the elements which are in triangular but marginally larger two standard deviation values. To avoid this drawback, the joint limiting distribution of the vector whose elements are in triangular of ESACF arrays is verified and the statistics to test the nulity of the vector suggested. We illustrate this approach with three examples.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.106-108
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• 2020

This paper introduces a new pulse-width modulation (PWM) method to reduce common-mode voltages (CMVs) and compare its performance with other reduced CMV-PWM (RCMV-PWM) methods. To avoid the use of zero-vectors which cause high CMV peaks, the introduced method splits every reference vector into two vectors such that the peak-to-peak magnitude of CMV is reduced by one-third of conventional space-vector PWM (SVPWM). The performance of RCMV-PWMs altered by the modulation index are analyzed with simulation results.

• 대한수학회보
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• 제34권2호
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• pp.273-285
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• 1997

The aim of this paper is to present theorems on the exitence of zeros for mappings defined on convex subsets of topological vector spaces with values in a vector space. In addition to natural assumptions of continuity, convexity, and compactness, the mappings are subject to some geometric conditions. In the first theorem, the mapping satisfies a "Darboux-type" property expressed in terms of an auxiliary numerical function. Typically, this functions is, in this case, related to an order structure on the target space. We derive an existence theorem for "obtuse" quasiconvex mappings with values in an ordered vector space. In the second theorem, we prove the existence of a "common zero" for an arbitrary (not necessarily countable) family of mappings satisfying a general "inwardness" condition againg expressed in terms of numerical functions (these numerical functions could be duality pairings (more generally, bilinear forms)). Our inwardness condition encompasses classical inwardness conditions of Leray-Schauder, Altman, or Bergman-Halpern types.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.264-267
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• 1989

In the vector controlled induction machine drives, mechanical speed sensors such as shaft encoder and resolver have been used. However, the mechanical speed sensors present some problems and restrict the wide applications of high performance AC drives. This paper describes the vector control strategy with the speed estimation algorithm in which motor slip frequency is calculated. Also, the angle deviation of the rotor flux vector is calculated and instaneously compensated to keep the q axis flux zero in the rotationary reference frame.

• 제어로봇시스템학회논문지
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• 제9권9호
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• pp.692-699
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• 2003

A novel rotor speed estimation method using Model Reference Adaptive Control(MRAC) is proposed to improve the performance of a sensorless vector controller. In the proposed mettled, the stator current is used as the model variable for estimating the speed. In conventional MRAC methods, the relation between the two model errors and the speed estmation error is unclear. Yet, in the proposed method, the stator current error is represented as a function of the first degree for the error value in the speed estimation. Therefore, the proposed method can produce a fast speed estimation and is robust to the parameters error In addition, the proposed method of offers a considerable improvement in the performance of a sensorless vector controller at a low speed. The superiority of the proposed method is verified by simulation and experiment in a low speed region and at a zero-speed.