• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.169-172
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• 2005

Modem SAR interferometry (IFSAR) sensors delivering intensity images and corresponding digital terrain model (DTM) allow for a thorough surface lineament interpretation with the all-weather day-night applicability. In this paper, an automatic linear-feature detection algorithm for high-resolution SAR images acquired in Taiwan is proposed. Methodologies to extract linear features consist of several stages. First, the image denoising techniques are used to remove the speckle noise on the raw image. In this stage, the Lee filter has been chosen because of its superior performance. After denoising, the Coefficient of Variation Detector is performed on the result images for edge enhancements and detection. Dilation and erosion techniques are used to reconnect the fragmented lines. The Hough transform, which is a special case of a more general transform known as Radon transform, is a suitable method for line detection in our analysis. Finally, linear features are extracted from the binary edge image. The last stage contains many substeps such as edge thinning and curve pruning.

• Journal of Communications and Networks
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• v.12 no.5
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• pp.475-479
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• 2010

The clipping value, defined as the log-likelihood ratio (LLR) in the case wherein all the list of candidates have the same binary value, is investigated, and an effective method to estimate it is presented for iterative tree search detection. The basic principle behind the method is that the clipping value of a channel bit is equal to the LLR of the maximum probability of correct decision of the bit to the corresponding probability of erroneous decision. In conjunction with multilevel bit mappings, the clipping value can be calculated with the parameters of the number of transmit antennas, $N_t$; number of bits per constellation point, $M_c$; and variance of the channel noise, $\sigma^2$, per real dimension in the Rayleigh fading channel. Analyses and simulations show that the bit error performance of the proposed method is better than that of the conventional fixed-value method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.8-13
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• 2005

In this paper discusses single-phase DC-AC Inverter design of reversible power converter that driven by binary combination at different transformer winding ratio by BCD code level. It has a advantage that constructs a control system simply and obtain load current of good quality without filter circuit and free from noise or isolation for lower switching frequency. In this research, study on current type converter and inverter circuit that consist for possibility of AC-DC/DC-AC multi-level reversible converter.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.303-305
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• 2003

This paper discusses single-phase AC-DC converter that driven by binary combination at different transformer winding ratio. It has a advantage that constructs a control system simply and obtain load current of good quality without filter circuit and free from noise or isolation for lower switching frequency. Also, this has merit that can do high power capacity. In this research, study on feedback circuit that consist for load stability of AC-DC multi-level converter.

• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1980-1987
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• 2000

In this paper, an efficient watermarking technique in wavelet transform domain is proposed. Watermarking is embedding a digital signal called as 'watermark' into images to claim the ownership. In the proposed method, the image is 1-level wavelet transformed, and then the watermark with a binary stamp is embedded into the baseband. The watermark is embedded by inverting the polarities of he selected coefficient paris. In the inverting process, we can increase image quality by finding means and differences of the selected neighboring coefficient paris, and then adding values, which are inversely proportional to the differences, to th means. The experimental results show that the proposed method has good quality and is robust to various attacks such as the JPEG lossy comparison, noise addition, clipping, blurring, etc.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.16-19
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• 2010

본 논문에서는 송신국과 릴레이에서의 오류확률을 고려한 복호 후 전달 릴레이(DF: Decoded and Forward) 시스템에 대하여 정확한 비트 오류율 분석을 수행하고자 한다. 성능 분석에서는 복호 후 전달 릴레이 시스템의 노드들 간의 채널을 상호 독립적인 레일리 페이딩 채널로 가정하고 변조 방식으로는 BPSK(Binary Phase Shift Keying)를 사용한다. 우선, 정확한 평균 오류율 분석을 위하여 송신국-수신국 링크와 릴레이-수신국 링크 결합시 릴레이노드의 복호결과 오류 유무에 따라 수신 SNR(Signal to Noise Ratio)을 각각 유도하고 복호결과가 오류일 때 수신 SNR이 양수인 경우와 음수인 경우를 고려하여 그에 대한 PDF(Probability Density Function)를 계산한다. 그리고 각각의 경우에 대한 평균 오류율을 유도하였다. 또한 모의실험 결과와의 비교를 통하여 제안된 성능 분석 기법의 정확성을 검증하였다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.1
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• pp.35-41
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• 2003

In this paper, a machine vision system for recognizing and classifying the patterns and marks engraved by die molding or laser marking on the glass panels of computer monitors is suggested and evaluated experimentally. The vision system is equipped with a neural network and an NGC pattern classifier including searching process based on normalized grayscale correlation and adaptive binarization. This system is found to be applicable even to the cases in which the segmentation of the pattern area from the background using ordinary blob coloring technique is quite difficult. The inspection process is accomplished by the use of the NGC hypothesis and ANN verification. The proposed pattern recognition system is composed of three parts: NGC matching process and the preprocessing unit for acquiring the best quality of binary image data, a neural network-based recognition algorithm, and the learning algorithm for the neural network. Another contribution of this paper is the method of generating the training patterns from only a few typical product samples in place of real images of all types of good products.

• Journal of Korea Multimedia Society
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• v.8 no.1
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• pp.27-33
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• 2005

In this paper, an effective skeleton method is proposed in order to obtain an enhanced digital image of skeleton line. The binary image using the threshold values is applied in the preprocessing stage and then The proposed method is applied to obtain the improved image of skeleton line. We used the existing skeleton methods and SPTA(Shin's Parallel Thinning Algorithm) method for the comparison. The demerits of the existing skeleton methods have a result of noise branch, expansion and contraction. and then we are proposed a SPTA method.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1689-1699
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• 2006

A nonlinear channel blind equalizer by using a hybrid genetic algorithm, which merges a genetic algorithm with simulated annealing, and a RBF network is presented. In this study, a hybrid genetic algorithm is used to estimate the output states of a nonlinear channel, based on the Bayesian likelihood fitness function, instead of the channel parameters. From these estimated output states, the desired channel states of the nonlinear channel are derived and placed at the center of a RBF equalizer to reconstruct transmitted symbols. In the simulations, binary signals are generated at random with Gaussian noise. The performance of the proposed method is compared with those of a conventional genetic algorithm(GA) and a simplex GA, and the relatively high accuracy and fast convergence of the method are achieved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1147-1152
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• 2012

In this paper, it is key issue about analysis of characteristics processing of digital random output stream of hardware random number generator, which is applied in medical area. The output stream of random number generator based on hardware binary random number is effected from factors such as delay, jitter, temperature, and so on. In this paper, it presents about major factor, which effects hardware output random number stream, and the randomness of output stream data, which are combined output stream and postprocessing data such as encryption algorithm, encoding algorithm, is analyzed. the analyzed results are evaluated by major test items of randomness.