• Smart Structures and Systems
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• 제15권1호
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• pp.81-97
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• 2015

Recently, a new output-only modal identification method based on time-frequency independent component analysis (ICA) has been developed by the authors and shown to be useful for even highly-damped structures. In many cases, it is of interest to identify the complex modes of structures with non-proportional damping. This study extends the time-frequency ICA based method to a complex ICA formulation for output-only modal identification of non-proportionally-damped structures. The connection is established between complex ICA model and the complex-valued modal expansion with sparse time-frequency representation, thereby blindly separating the measured structural responses into the complex mode matrix and complex-valued modal responses. Numerical simulation on a non-proportionally-damped system, laboratory experiment on a highly-damped three-story frame, and a real-world highly-damped base-isolated structure identification example demonstrate the capability of the time-frequency complex ICA method for identification of structures with complex modes in a straightforward and efficient manner.

• 시스템엔지니어링학술지
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• 제3권1호
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• pp.27-31
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• 2007

A complex system like ATM(Air Traffic Management) has safety problem emerging from complex interactions between systems. In complex systems, malfunctions of components are not the only causes of critical accidents. To resolve this problem many researchers have proposed new safety analysis models for complex systems. This research is a way of improving safety analysis model focusing on systems engineering design model for ATM.

• 한국화재소방학회논문지
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• 제25권4호
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• pp.42-47
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• 2011

본 연구에서는 환기 및 소방용 복합댐퍼의 개발을 위한 기초 연구의 일환으로 복합댐퍼의 설계인자에 관한 연구를 수행하였다. 본 연구는 복합댐퍼의 프로세스와 운동 메커니즘, 기구 모델링을 바탕으로 복합댐퍼의 설계 및 해석이론을 제시하였고, 설계 및 해석이론을 바탕으로 한 운동해석 시뮬레이션을 통해 복합댐퍼의 각 요소를 설계할 수 있는 엔지니어링 데이터 구축과 원천기술을 확립하였다. 따라서 본 연구를 통해 환기 및 소방용 복합댐퍼 개발에 폭넓게 응용할 수 있는 결과를 얻었다. 본 연구를 바탕으로 복합댐퍼가 개발되면 환기풍도로부터 유입되는 연기제어와 기술적 대책을 마련할 수 있을 것으로 본다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.58-63
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• 1998

B.Widrow established fundamental relations between the least-mean-square (LMS) algorithm and the digital Fourier transform［1］. By extending these relations, we proposed the short time spectra analysis system using the LMS algorithm［2]. In that paper, we used the normal LMS algorithm on the thought of dealing with only real analytical signal. This algorithm minimizes the real mean-square by recursively altering the complex weight vector at each sampling instant. But, the short time spectra analysis sometimes deals with the complex signal that is outputted from complex analog filter. So, in order to optimize and develop this methods, furthermore it is necessary to derive an algorithm for the complex analytical signal. In this paper, we first discuss the new adaptive system for the spectra analysis using the complex LMS algorithm and then derive convergence condition, time constant of coefficient adjustment and frequency resolution by extending the discussion. Finally, the effectiveness of the proposed method is experimentally demonstrated by applying it to the measurement of transfer performance on complex analog filter.

• 대한수학회보
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• 제54권4호
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• pp.1229-1240
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• 2017

This paper presents a systematic study of the abstract harmonic analysis over spaces of complex measures on homogeneous spaces of compact groups. Let G be a compact group and H be a closed subgroup of G. Then we study abstract harmonic analysis of complex measures over the left coset space G/H.

• 한국수학사학회지
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• 제21권4호
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• pp.141-152
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• 2008

본 연구는 복소수의 교수학적 분석인데 주로 문제해결에 필요한 지식의 연결성에 초점을 맞추고 있으며 복소수 개념이 학교수학에서 핵심적 역할을 한다는 것을 보이고 있다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2003년도 춘계종합학술대회논문집
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• pp.351-355
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• 2003

포유류 동물의 시각피질 세포에 나타나는 특징은 크게 단순특징을 추출하는 simple cell과 복잡한 특징에 반응하는 complex cell로 구분된다. 이 연구에서는 입력영상에 독립성분분석을 적응하여 complex cell에 대응하는 복잡한 특징을 추출하였다. 이 결과는 시각피질 세포의 정보처리에 대한 방식을 이해하는 데 기여할 것이다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제7권2호
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• pp.51-64
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• 2003

Analysis is given of construction and stability of complex symmetric analogues of Householder matrices, with applications to the eigenproblem for such matrices. We investigate numerical properties of the deflation of complex symmetric matrices by using complex symmetric Householder transformations. The proposed method is very similar to the well-known deflation technique for real symmetric matrices (Cf. [16], pp. 586-595). In this paper we present an error analysis of one step of the deflation of complex symmetric matrices.

• 한국유기농업학회지
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• 제25권1호
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• pp.1-22
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• 2017

The purpose of this research is to analysis actual condition of promoting complex industrialization and changes after promoting, and then to classify organic farmer using cluster analysis based on delineated organic farmer's changes factors. This study also aims to investigate differences in socioeconomic characteristics and behavioral intentions among classified groups of organic farmer's changes. Data were obtained by questionnaire. From the factor analysis, four factors were derived as "Economics", "Public benefit", "Environment and philosophical values" and "Establishing management and the regional bedrock". From the cluster analysis, three cluster were derived as "group that has a positive awareness of promoting complex industry", "group that has a negative awareness of promoting complex industry" and "unstable management and a regional base". And the three classifications were significantly different in the satisfaction and behavioral intentions.

• Geomechanics and Engineering
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• 제17권3호
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• pp.227-236
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• 2019

In practice, the natural slopes are frequently with soils of spatial properties and irregular features. The traditional limit analysis method meets an inherent difficulty to deal with the stability problem for such slopes due to the normal condition in the associated flow rule. To overcome the problem, a novel technique based on the upper bound limit analysis, which is called the discretization technique, is employed for the stability evaluation of complex slopes. In this paper, the discretization mechanism for complex slopes was presented, and the safety factors of several examples were calculated. The good agreement between the discretization-based and previous results shows the accuracy of the proposed mechanism, proving that it can be an alternative and reliable approach for complex slope stability analysis.