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Optimum Array Processing with Variable Linear Constraint
Chang, Byong Kun The Korea Institute of Information and Commucation 2014 Journal of information and communication convergen Vol.12 No.3
A general linearly constrained adaptive array is examined in the weight vector space to illustrate the array performance with respect to the gain factor. A narrowband linear adaptive array is implemented in a coherent signal environment. It is shown that the gain factor in the general linearly constrained adaptive array has an effect on the linear constraint gain of the conventional linearly constrained adaptive array. It is observed that a variation of the gain factor of the general linearly constrained adaptive array results in a variation of the distance between the constraint plane and the origin in the translated weight vector space. Simulation results are shown to demonstrate the effect of the gain factor on the nulling performance.
General Linearly Constrained Broadband Adaptive Arrays in the Eigenvector Space
Chang, Byong Kun The Korea Institute of Information and Commucation 2017 Journal of information and communication convergen Vol.15 No.2
A general linearly constrained broadband adaptive array is examined in the eigenvector space with respect to the optimal weight vector and the adaptive algorithm. The optimal weight vector and the general adaptive algorithm in the eigenvector space are obtained by eigenvector matrix transformation. Their operations are shown to be the same as in the standard coordinate system except for the relevant transformed vectors and matrices. The nulling performance of the general linearly constrained broadband adaptive array depends on the gain factor such that the constraint plane is shifted perpendicularly to the origin by an increase in the gain factor. The general linearly constrained broadband adaptive array is observed to perform better than a conventional linearly constrained adaptive array in a coherent signal environment, while the former performs similarly to the latter in a non-coherent signal environment.
Linearly Constrained Adaptive Array Processing with Alternate Mainbeam Nulling
Byong Kun Chang,Chang Dae Jeon,Dong Hyuk Song 한국전자파학회JEES 2008 Journal of Electromagnetic Engineering and Science Vol.8 No.2
This paper concerns with signal cancellation problem in a linearly constrained adaptive array processor in coherent environment. Alternate mainbeam nulling approach was proposed to prevent the signal cancellation phenomenon. The linearly constrained LMS algorithm with a unit gain constraint and that with a null constraint in the direction of the desired signal is alternately implemented to reduce the signal interaction between the desired signal and the interferences, which is the main cause of the signal cancellation. It is shown that the proposed method performs better than a conventional method.
Chang, Byong-Kun,Jeon, Chang-Dae,Song, Dong-Hyuk The Korea Institute of Information and Commucation 2009 Journal of information and communication convergen Vol.7 No.3
A novel approach is presented to improve the array performance of the alternate mainbeam nulling in a linearly constrained adaptive array processor in coherent environment. The convergence parameters in the linearly constrained LMS algorithm with a unit gain constraint and a null constraint in the direction of the desired signal are adaptively estimated to reduce the error power between the desired signal and the array output in the 2-dimensional convergence parameter space. It is shown that the case for estimating the convergence parameter for the unit gain constraint with that for null constraint fixed performs best. Also, it is observed that the proposed method performs significantly better than conventional methods as the number of coherent interferences increases.
A Novel Approach to General Linearly Constrained Adaptive Arrays
Chang, Byong-Kun,Kim, Tae-Yeon,Lee, Yong-Kwon The Korea Institute of Information and Commucation 2012 Journal of information and communication convergen Vol.10 No.2
A novel approach to general linearly constrained adaptive arrays is presented to improve the nulling performance in coherent and noncoherent environments. The narrowband and broadband linearly constrained adaptive arrays are implemented to examine the array performance. It is shown that the proposed approach performs better than the conventional adaptive arrays and the nulling performance depends on the gain factor for the desired response.
General Linearly Constrained Narrowband Adaptive Arrays in the Eigenvector Space
Chang, Byong Kun The Korea Institute of Information and Commucation 2017 Journal of information and communication convergen Vol.15 No.3
A general linearly constrained narrowband adaptive array is examined in the eigenvector space. The optimum weight vector in the eigenvector space is shown to have the same performance as in the standard coordinate system, except that the input signal correlation matrix and look direction steering vector are replaced with the eigenvalue matrix and transformed steering vector. It is observed that the variation in gain factor results in the variation in the distance between the constraint plane and the origin in the translated weight vector space such that the increase in gain factor decreased the distance from the constraint plane to the origin, thus affecting the nulling performance. Simulation results showed that the general linearly constrained adaptive array performed better at an optimal gain factor compared with the conventional linearly constrained adaptive array in a coherent signal environment and the former showed similar performance as the latter in a noncoherent signal environment.
Chang, Byong-Kun The Acoustical Society of Korea 1999 韓國音響學會誌 Vol.18 No.e4
This paper concerns a modified perturbation method and a least square approach to synthesize an optimum beam pattern of a thinned sensor array with respect to element spacing. In the modified perturbation, the antenna spacing is perturbed iteratively such that the sidelobes are equalized via a linear programming approach. The least square approach is proposed to improve the array performance for the thinned array using the fact that the number of sidelobes is more than the number of element spacings. It is demonstrated that the least square approach performs better than the modified perturbation method.
Optimum Design of Thinned Microphone Arrays Using a Modified Perturbation Approach
Chang, Byong-Kun The Acoustical Society of Korea 1998 韓國音響學會誌 Vol.17 No.e4
A modified perturbation method is proposed to optimize the beam pattern of thinned microphone arrays. Both microphone spacing and array weight are iteratively adjusted via successive perturbation to achieve an optimum beam pattern in a Dolph Chebyshev sense. To improve the sidelobe performance, an alternative perturbation with respect to microphone spacing and array weight is implemented. Also, a linear space-tapering is employed in the perturbation process. It is demonstrated that the proposed approaches successfully yield sidelobe performances comparable to that of a normal array. Computer simulation results are presented.
효율적인 Web기반 조명시설 제어 및 관리 시스템의 개발
장병건(Byong Kun Chang),진창대(Chang Dae Jeon) 한국조명·전기설비학회 2004 한국조명·전기설비학회 학술대회논문집 Vol.2004 No.11월
In this paper, PDA(Personal Digital Assistants) terminal is proposed to be used for controlling and managing light facilities efficiently by connecting it to a web-based server system and adding additional functions. The control box of current light facilities may be implemented based on a simple On-Off function. The operational quality of the light facilities will be efficiently improved with some practical advantages such as reduction of required facility, manpower and time in managing the lights and control boxes by using the popular PDA.