• 한국통신학회논문지
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• 제25권6B호
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• pp.1092-1099
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• 2000

An adaptive array system can effectively remove all received interferences by using adaptive algorithms even though the received signal condition is not known. The conventional adaptive array systems, however, cannot remove all interferences adaptively and converge very slowly when the eigenvalue spread of the input covariance matrix is large. In the paper, a new adaptive array system called an automatic gain controller (AGC) Applebaum array and its control algorithm are proposed to overcome the performance degradation of conventional Applebaum array in multiple interference conditions. The performance analysis of the proposed AGC Applebaum array is described under the condition of multiple narrowband interferences. Simulation results show the array output signal-to-noise ratio (SNR) of the AGC Applebaum array increases by 30dB compared to that of the conventional Applebaum array in the simulation condition. The gain of the AGC Applebaum array in the incident direction of a weaker interference is also shown to be lower than that of the conventional Applebaum array.

• 대한전자공학회논문지TC
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• 제46권12호
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• pp.44-51
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• 2009

핀 배열 안테나를 이용한 선형 위상 배열 안테나의 방사 특성을 일반적인 패치안테나를 이용한 선형 위상 배열 안테나와 방사 특성을 비교하였다. 핀 배열 안테나를 이용한 위상 배열 안테나는 단위 안테나간의 상호결합이 작게 발생하기 때문에 일반적인 패치안테나를 이용한 위상 배열 안테나의 성능보다 향상되었다. 핀 태열 안테나를 이용한 선형 위상 배열 안테나는 주빔의 방향에 따른 이득과 side lobe level 의 변화가 적은 우수한 방사 특성을 가진다.

• Advances in Computational Design
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• 제8권4호
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• pp.273-293
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• 2023

This study evaluated the acoustic performance of two configurations of serial HR arrays and lined HR arrays in the presence of grazing flow using a 3D numerical simulation. The dual, triple, and quad HR arrays were compared to the conventional HR array. The simulation results showed that the number of resonant frequencies increased with the number of serial HR arrays. The C_TL did not significantly change with the number of serial HR arrays. The acoustic performance of the two, three, and four-lined HR arrays was compared to the conventional HR array. The results showed that the resonant frequency and TLmax increased with the number of lined HR arrays. The C_TL also increased with the number of lined HR arrays. The effect of the grazing flow Mach number (M_a) was investigated on the four-lined HR array configuration and compared to the conventional HR configuration. TLmax and C_TL decreased for both configurations with increasing M_a. The four-lined HR array configuration had significantly better acoustic performance than the conventional HR configuration. The TLmax and C_TL increased by more than 300% when the configuration was changed from the conventional HR to the four-lined HR array at M_a = 0.The increment percentage decreased with increasing M_a.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.141-144
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• 2000

In this paper, a new parallel array structure for the asynchronous array multiplier is introduced. This structure is designed for a data dependent asynchronous multiplier to reduces power which is wasted in conventional array structure. Simulation shows that this structure saves 30％ of power and 55％ of computation time comparing to conventional booth encoded array multiplier.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.855-857
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• 2000

Brake system using eddy current is adequate to obtain safe braking force in high speed transportation system and electric vehicle etc. In this paper, we propose the new type eddy current braker using Halbach array. which compared with the conventional permanent magnet array. The airgap flux density of Halbach array is higher 25% then conventional array, therefor we can predict that braking force is much large 1.56 times then conventional array.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
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• pp.242-245
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• 2000

In this paper, we present a color interpolation technique based on artificial neural networks for a single-chip CCD (charge-coupled device) camera with a Bayer color filter array (CFA). Single-chip digital cameras use a color filter array and an interpolation method in order to regenerate high quality color images from sparsely sampled images. We applied 3-layer feedforward neural networks in order to interpolate missing pixel from surrounding pixels. And we compared the proposed method with conventional interpolation methods such as the proposed interpolation algorithm based on neural networks provides a better performance than the conventional interpolation algorithms.

• 전자공학회논문지S
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• 제34S권10호
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• pp.132-140
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• 1997

This paper proposes systolic array architectures for compuataion of the 1-D and 2-D discrete wavelet transform (DWT). The proposed systolic array for compuataion of the 1-D DWT consists of L processing element (PE) arrays, where the PE array denotes the systolic array for computation of the one level DWT. The proposed PE array computes only the product terms that are required for further computation and the outputs of low and high frequency filters are computed in alternate clock cycles. Therefore, the proposed architecuter can compute the low and high frequency outputs using a single architecture. The proposed systolic array for computation of the 2-D DWT consists of two systolic array architectures for comutation of the 1-D DWT and memory unit. The required time and hardware cost of the proposed systolic arrays are comparable to those of the conventional architectures. However, the conventional architectures need extra processing units whereas the proposed architectures fo not. The proposed architectures can be applied to subband decomposition by simply changing the filter coefficients.

• 대한전자공학회논문지TC
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• 제46권10호
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• pp.63-71
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• 2009

여러 가지 기판 두께에서 동작 주파수를 일정하게 유지하면서 좋은 방사 특성을 가지는 핀 배열을 가지는 패치 안테나에 대해 연구하였다. 수평방향으로의 방사를 최대로 억제시키는 핀 배열 패치 안테나의 패치 길이가 기판 두께가 증가함에 따라 작아짐을 볼 수 있었다. 핀 배열 패치 안테나는 기본 패치 안테나보다 수평방향으로의 방사가 크게 억제되고 전방방사 이득이 증가하며 후방방사는 감소함을 볼 수 있다. 또한 핀 배열 패치 안테나의 E-plane 방사 패턴의 Half-power beamwidth가 기본 패치 안테나보다 작아져 안테나의 지향성이 향상됨을 볼 수 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.164-169
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• 2005

Microphone array techniques are being used widely in wind tunnel measurements for identification of the distributed aerodynamic noise sources on the model being tested. Depending on the frequencies and sound levels, conventional beamforming algorithm has limitation in separating two adjacent sources. Several modifications to the classical beamforming have been developed to enhance way resolution and reduce sidelobe levels. In this Paper the robust adaptive beamforming and the CLEAN algorithm are used to compare to the result of conventional beamforming method. It is found that the CLEAN algorithm is capable of pin-pointing locations of multiple sources nearby, while these sources are unidentifiable with robust adaptive or conventional beamforming techniques.

• Journal of electromagnetic engineering and science
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• 제18권3호
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• pp.175-181
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• 2018

The array patterns of a patch array antenna were calculated using an active element pattern (AEP) method that considers ground edge effects. The classical equivalent radiation model of the patch antenna, which is characterized by two radiating slots, was adopted, and the AEPs that include mutual coupling were precisely calculated using full-wave simulated S-parameters. To improve the accuracy of the calculation, the edge diffraction of a ground plane was incorporated into AEP using the uniform geometrical theory of diffraction. The array patterns were then calculated on the basis of the computed AEPs. The array patterns obtained through the conventional AEP approach and the AEP method that takes ground edge effects into account were compared with the findings derived through full-wave simulations conducted using a High Frequency Structure Simulator (HFSS) and FEKO software. Results showed that the array patterns calculated using the proposed AEP method are more accurate than those derived using the conventional AEP technique, especially under a small number of array elements or under increased steering angles.