• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.33-51
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• 1999

In this study, the system level network simulation is considered with adaptive array antenna in CDMA mobile communication system. A network simulation framework is implemented based on IS-95A/B system to consider dynamic handoff, system level network behavior, and deploying strategy into the overall CDMA mobile communication network under adaptive array algorithm. Its simulation model, such as vector channel model, adaptive beam forming antenna model, handoff model, and power control model, are described in detail with simulation block. In order to maximize SINR of received signal at antenna, Maximin algorithm is particularly considered, and it is computed at each simulation snap shot with SINR based power control and handoff algorithm. Graphic user interface in this system level network simulator is also implemented to define the simulation environments and to represent simulation results on real mapping system. This paper also shows some features of simulation framework and simulation results.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.113-116
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• 2001

Reed-Solomon(RS) code is the most powerful burst error correcting code. In Ois paper, the architecture for the adaptive RS encoder adaptable for multi QoS requirements or time-varying channel environments has been designed. In the adaptive RS code, the message length k and the error correction capability t are allowed to be variable so that the block length n is also variable. We proposed the architecture of the adaptive RS encoder by designing the optimal structure of Galois fields multiplier with comparison of fixed multiplier and variable multiplier. The proposed architecture is implemented in VHDL and verified with the simulation tool

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.167-170
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• 1998

본 논문에서는 주파수 영역에서 구현되는 안테나 배열을 이용한 적응형 등화기의 구조를 제안하였다. 제안된 방식은 주파수 영역에서 블록 LMS (least mean squares) 방식을 사용하기 때문에 수렴 속도가 빠르고 계산량이 적다. 또한 안테나 배열을 사용함으로서 다중경로 환경에서 한 개의 안테나를 사용한 경우에 비해 특히 우수한 성능을 지닌다. 다중 경로를 통한 신호들을 분리하기 위해 학습신호를 사용하여 반복적으로 출력신호와의 오차를 최소화하는 방법을 사용하였다. 시뮬레이션을 통하여 안테나의 개수, 신호의 입사각, 세기 등에 따른 성능을 분석하고, 제안된 방식이 다이버시티 시스템에 사용되는 경우에 대하여도 성능을 분석하였다.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1418-1421
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• 1987

An important problem in edge detection is to select a proper threshold that transforms the gradient picture to e two level picture containing optimum edges between regions, Such a threshold is determined depending on some measures of errors in tresholding. In this paper, an error criterion on extracting edges by thresholding the block gradient image is presented. Based on the error measure, the optimum threshold is chosen for the detection of acceptable edges.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.133-136
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• 2003

In this paper, we propose a low bit-rate embedded video coding scheme with 3-D block partition in the wavelet domain. The proposed video coding scheme includes multi-level three dimensional dyadic wavelet decomposition, raster scanning within each subband, partitioning of blocks, and adaptive arithmetic entropy coding. Although the proposed video coding scheme is quite simple, it produces bit-streams with good features, including SNR scalability from the embedded nature. Experimental results demonstrate that the proposed video coding scheme is quite competitive to other good wavelet-based video coders in the literature.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.33-36
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• 1998

Most image restoration problems are ill-posed and need to e regularized. A difficult task in image regularization is to avoid smoothing of image edges. In this paper, were proposed an edge-preserving image restoration algorithm using block-based edge classification. In order to exploit the local image characteristics, we classify image blocks into edge and no-edge blocks. We then apply an adaptive constrained least squares (CLS) algorithm to eliminate noise around the edges. Experimental results demonstrate that the proposed algorithm can preserve image edges during the regularization process.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.81-84
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• 1990

This paper presents a method of sub-optimal control for nonlinear systems via block pulse transformation. The adaptive optimal control scheme proposed by J.P. Matuszewski is introduced to minimize the performance index. The proposed method is simple and computationally advantageous. Viablity of the this method is established with simulation results for the van der Pole equation for comparision with other methods.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.101-104
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• 2001

This paper proposes a unique shot boundary detection algorithm for the video indexing and/or browsing. Conventional methods based on the frame differences and the histogram differences are improved. Instead of using absolute frame differences, block by block based relative frame differences are employed. Frame adaptive thresholding values are also employed for the better detection. for the cases that the frame differences are not enough to detect the shot boundary, histogram differences are selectively applied. Experimental results show that the proposed algorithm reduces both the “false positive” errors and the “false negative” errors especially for the videos of dynamic local and/or global motions

• ETRI Journal
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• v.32 no.3
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• pp.380-389
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• 2010

This paper presents a new edge-protection algorithm and its very large scale integration (VLSI) architecture for block artifact reduction. Unlike previous approaches using block classification, our algorithm utilizes pixel classification to categorize each pixel into one of two classes, namely smooth region and edge region, which are described by the edge-protection maps. Based on these maps, a two-step adaptive filter which includes offset filtering and edge-preserving filtering is used to remove block artifacts. A pipelined VLSI architecture of the proposed deblocking algorithm for HD video processing is also presented in this paper. A memory-reduced architecture for a block buffer is used to optimize memory usage. The architecture of the proposed deblocking filter is verified on FPGA Cyclone II and implemented using the ANAM 0.25 ${\mu}m$ CMOS cell library. Our experimental results show that our proposed algorithm effectively reduces block artifacts while preserving the details. The PSNR performance of our algorithm using pixel classification is better than that of previous algorithms using block classification.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.2
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• pp.73-78
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• 2004

By modeling the block matching algorithm as a function of the correlation of image blocks, we derive search patterns for fast block matching motion estimation. The proposed approach provides an analytical support lot the diamond-shape search pattern, which is widely used in fast block matching algorithms. We also propose a new fast motion estimation algorithm using adaptive search patterns and statistical properties of the object displacement. In order to select an appropriate search pattern, we exploit the relationship between the motion vector and the block differences. By changing the search pattern adaptively, we improve motion prediction accuracy while reducing required computational complexity compared to other fast block matching algorithms.