• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.91-97
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• 2005

In the mobile antenna systems for satellite multimedia communications, the active way antenna having a low sidelobe antenna pattern is described in this paper. This designed and fabricated array antenna is satisfied with international beam pattern regulation on moving states. The subarray of the proposed mobile antenna system is arranged with a stair-planar structure and non-periodic array spacing. This subarray is designed with three-layered microstrip patch as both receiving and transmitting radiator of which are improved with antenna gain and bandwidth. Also, the optimum subarray spacing is designed to make the lowest sidelobe pattern by genetic algorithm. In addition, the characteristics of a GA-perturbed array are investigated from simulated and measured beam pattern results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1201-1208
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• 2009

The Direction-Of-Arrival(DOA) resolution of signals depends on the aperture size of the array. Therefore it is not easy to resolve closely spaced coherent signals impinge on an array with a small radius. In order to overcome the problem, a new method is proposed to use the characteristic of spatial spectrums for arrays which have different aperture sizes after virtually expanding the spacing of original antenna array. In case of coherent signals impinge on an uniform circular array, the perfect DOA resolution capability of 100 % is achieved at the SNR range of -10 dB to 0 dB by the Deterministic Maximum Likelihood(DML) algorithm including the proposed method. On the other hand, the standard DML algorithm can not resolve signals at all at the same SNR.

• Journal of Sensor Science and Technology
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• v.22 no.2
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• pp.162-173
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• 2013

The purpose of this paper is to classify VOC gases by emulating the characteristics found in biological olfaction. For this purpose, we propose new signal processing method based a polymeric chemical sensor array consisting of 4096 sensors which is created by NEUROCHEM project. To remove unstable sensors generated in the manufacturing process of very large scaled chemical sensor array, we used discrete wavelet transformation and cosine similarity. And, to remove the supernumerary redundancy, we proposed the method of selecting candidates of representative sensor representing sensors with similar features by Fuzzy c-means algorithm. In addition, we proposed an improved algorithm for selecting representative sensors among candidates of representative sensors to better enhance classification ability. However, Classification for very large scaled sensor array has a great deal of time in process of learning because many sensors are used for learning though a redundancy is removed. Throughout experimental trials for classification, we confirmed the proposed method have an outstanding classification ability, at transient state as well as steady state.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.3
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• pp.224-228
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• 2015

In this paper, we study the method for desired signals estimation that array antennas are received signals. We apply sub spatial method of direction of arrival algorithm and adaptive array antennas in order to remove interference and noise signal of received antenna signals. Array response vector of adaptive array antenna is probability, it is correctly estimation of direction of arrival of targets to update weight signal. Desired signals are estimated updating covariance matrix after moving interference and noise signals among received signals. We estimate signals using eigen decomposition and eigen value, high resolution direction of arrival estimation algorithm is devided signal sub spatial and noise sub spatial. Though simulation, we analyze to compare proposed method with general method.

• Journal of KIISE
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• v.43 no.1
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• pp.13-26
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• 2016

This paper proposes a new sound localization algorithm that can improve localization performance based on a tetrahedron-shaped microphone array. Sound localization system estimates directional information of sound source based on the time delay of arrival(TDOA) information between the microphone pairs in a microphone array. In order to obtain directional information of the sound source in three dimensions, the system requires at least three microphones. If one of the microphones fails to detect proper signal level, the system cannot produce a reliable estimate. This paper proposes a tetrahedron- shaped sound localization system with a coordinate transform method by adding one microphone to the previously known triangular-shaped system providing more robust and reliable sound localization. To verify the performance of the proposed algorithm, a real time simulation was conducted, and the results were compared to the previously known triangular-shaped system. From the simulation results, the proposed tetrahedron-shaped sound localization system is superior to the triangular-shaped system by more than 46% for maximum sound source detection.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.218-223
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• 1993

In this paper, we modify a multiple target angle tracking algorithm presented by Sword et al.. The predicted estimates, instead of the existing estimates, of the target angles are updated by the most recent output of the sensor array to improve the tracking performance of the algorithm for crossing targets. Also, the least square solution is modified to avoid abnormally large angle innovations when the target angles are very close. The improved performance of the proposed algorithm is demonstrated by computer simulations.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.851-856
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• 1987

A direct computation algorithm of two dimensional fast Fourier transform (2D-FFT) is considered here for implementation in mesh connected multiprocessor array of both a 2D-toroidal and a rectangular type. Results are derived for a hardware algorithm including data allocation and interprocessor communications. A performance comparison is carried out between the proposed direct 2D-FFT computation and the conventional one to show that a new algorithm gives higher speedup under a reasonable assumption on the speeds of operations.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.5
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• pp.81-87
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• 1994

This paper proposes a divider structure that combines a carry-propagation-free division algorithm using RSD number system and a self-timed ring structure. The self-timed ring structure enables the divider to compute at a speed comparable to that of combinational array dividers with less silicon area. By exploiting the carry-propagation-free division algorithm, we can achieve further reduction of silicon area and computation time. The algorithm and structure of the proposed divider have been successfully verified through VHDL modeling and simulation. Preliminary experimental results show the effectiveness of the algorithm and structure.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.1
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• pp.19-29
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• 2019

This paper analyzes the design factors for GNSS anti-jamming receiver system in which the adaptive beamforming algorithm is applied in GNSS receiver system. The design analysis factors used in this paper are divided into three: antenna, beamforming algorithm, and operation environment. This paper analyzes the above three factors and presents numerical simulation results on antenna and beamforming algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.187-195
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• 2012

In this paper, we propose the optimization of subarray configurations for linear array to minimize the side lobe level (SLL) in sum beam pattern based on the genetic algorithm. The operations of genetic algorithm are modified to be applied to subarray configurations. Using the proposed method, we construct subarray structure with 16 irregular subarray elements from 40 linear array elements to minimize the SLL in sum beam pattern in case of applying the adaptive beamforming(ABF) to suppress the jamming power, whose the SLL is 10 dB lower than that of regular subarray configuration.