• Journal of Mechanical Science and Technology
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• 제19권3호
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• pp.731-742
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• 2005

A magnetic bearing even with multiple coil failure can produce the same decoupled magnetic forces as those before failure if the remaining coil currents are properly redistributed. This fault-tolerant, force invariance control can be achieved with simply replacing the distribution matrix with the appropriate one shortly after coils fail, without modifying feedback control law. The distribution gain matrix that satisfies the necessary constraint conditions of decoupling linearized magnetic forces is determined with the Lagrange Multiplier optimization method.

• Korean Journal of Geomatics
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• 제3권1호
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• pp.23-32
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• 2003

Rigorous sensor and dynamic modeling techniques are required if spatial information is to be accurately extracted from video imagery. First, a mathematical model for an uncalibrated video camera and a description of a bundle adjustment with added parameters, for purposes of general block triangulation, is presented. This is followed by the application of invariance-based techniques, with constraints, to derive initial approximations for the camera parameters. Finally, dynamic modeling using the Kalman Filter is discussed. The results of various experiments with real video imagery, which apply the developed techniques, are given.

• 대한수학회논문집
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• 제17권1호
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• pp.155-163
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• 2002

The purpose of this paper is to establish discrete versions of the well-known Lyapunov's stability theorem and LaSalle's invariance theorem for a non-autonomous discrete dynamical system. Our proofs for these theorems are constructive in the sense that they are made by explicitly building a Lyapunov function for the system. A comparison between non-autonomous discrete dynamical systems and continuous dynamical systems is conducted.

• 대한수학회보
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• 제49권4호
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• pp.863-874
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• 2012

We provide a study of lightlike hypersurfaces of a generalized Robertson-Walker (GRW) space-time. In particular, we investigate lightlike hypersurfaces with curvature invariance, parallel second fundamental forms, totally umbilical second fundamental forms, null sectional curvatures and null Ricci curvatures, respectively.

• Journal of applied mathematics & informatics
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• 제26권5_6호
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• pp.1161-1168
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• 2008

We prove a theorem that there exists at least a solution reaching the prescribed target in autonomous differential inclusion. A weak invariance theorem is obtained from this theorem as its corollary. To deduce the conclusion, we assume that the target satisfies inward pointing condition. This condition will be given by proximal normal cone.

• 전자공학회논문지A
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• 제33A권6호
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• pp.178-188
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• 1996

In this paper, we propose a new opto-digital object recognition system which has rotation, scale, and shift invariant characteristics. The fourier power spectrum of the object image is modified to get shift invariance. The log-polar transform is used for rotation and scale invariance. And the decision of similarities is performed by nonlinear joint transform correlator (NJTC) that can control the ratio of phase and amplitude signals. Experimental verification of th eproposed optical object recognition system is presented.

• 대한수학회지
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• 제17권2호
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• pp.265-267
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• 1981

• 전자공학회논문지
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• 제49권9호
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• pp.164-171
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• 2012

센서 어레이(sensor array)가 천이불변(shift invariance) 성질을 가질 때, ESPRIT(Estimation of Signal Parameter via Rotational Invariance Techniques) 방식은 이를 이용하여 어레이에 도래하는 신호의 도래각을 추정한다. 본 논문에서는 ESPRIT 방식을 적용하여 코히런트 신호의 도래각을 효과적으로 추정하는 방법을 제시한다. ESPRIT 방식은 신호부공간(signal subspace)을 이용한다. 코히런트 신호가 존재할 때, 신호부공간을 구하는 방법으로 SS(spatial smoothing) 방식이 널리 알려져 있으나 계산이 매우 복잡하다. 최근에 발표된 CV(correlation vector)에 기초한 방식은 계산은 간단하지만 SS 방식보다 작은 수의 신호를 분해한다. 제안 방식은 상관행렬의 일부를 이용하여 신호부공간을 구성하여 도래각을 추정한다. SS 방식과 비교하여, 제안 방식에서는 분해 가능한 신호의 수는 동일하면서 계산량을 크게 줄일 수 있다.

• 감성과학
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• 제21권3호
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• pp.103-114
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• 2018

SPANE(the Scale of Positive and Negative Experience) 척도는 기존 정서 측정도구의 한계를 보완하기 위해 Diener 등(2010)이 개발한 정서적 안녕감 척도이다. 이 척도는 긍정적 정서와 부정적 정서 경험을 측정하는 총 12문항으로 구성되어 있으며, 포괄적 정서(e.g. positive, negative)와 구체적 정서(e.g. joyful, sad) 문항이 포함되어 있다. 각성수준의 측면에서도 고(e.g. joy, angry), 중(e.g. happy, afraid), 저(e.g. contented, sad) 각성 정서들이 모두 반영되어 있다. 본 연구는 한국판 SPANE 척도의 요인구조 및 성별 측정 동일성을 검토하였다. 이를 위해서, 한국 대학생 총 551명(남자 276, 여자 275)의 자료를 분석했다. 그 결과, SPANE 척도는 양호한 수준의 신뢰도와 요인 타당도를 보였다. 또한 남녀 집단 간에 요인구조, 요인부하량, 절편이 동일한 것으로 나타나서, 성별 척도 동일성이 확인되었다. 이러한 결과는 SPANE 척도가 한국에서도 대학생들의 정서적 안녕감을 측정하기에 적합한 척도일 뿐 아니라 성별 차이를 비교하는 타당한 도구가 될 수 있음을 시사한다.

• Asia pacific journal of information systems
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• 제16권1호
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• pp.103-125
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• 2006

Online game business has emerged as the most lucrative entertainment industry, with over 10 million players in South Korea and over 30million in Japan in 2005. While the interactive entertainment market continues to expand, with many new online game publishers entering the market, relatively little theory has been developed about which factors influence online gamers' behavioral intentions (i.e., loyalty, satisfaction, words of mouth, etc.) in this area. The purpose of this research is to investigate the relationships among the gamers' satisfaction, trust toward game publishers, the role of online game community, social reputation, and the managerial support of game publishers. We also examine the differences between Korean and Japanese gamers concerning the relationships of these key success factors. The structural model is tested with the data from entire data samples (i.e., Korean and Japanese gamers pooled together) and each of the sub-samples (i.e., Korean and Japanese gamers taken separately). Properties of the causal paths, including standardized path coefficients, the significance of difference, and variance explained for Trust and Satisfaction in the hypothesized model, are presented. Following the model test, we conduct a test of the differences in path coefficients between Korean and Japanese gamers. Statistical results show that, compared to Japanese gamers, Korean gamers had a greater salient effect on Social Reputation in determining. Trust, in addition to placing a greater emphasis on Support of Game Publishers in determining Social Reputation. Other interesting results concerning game Publishers' strategy are also presented.