• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9B
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• pp.1588-1595
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• 2000

To restore image degraded by out-of-focus blur and additivie noise a regularized iterative restoration is used. In concentional method, regularization is usually applied to all over the image without considering the local characteristics of image. As a result, ringing artifacts appear in edge regions and the noise amplification is introduced in flat regions. To solve this problem we propose an adaptive regularization iterative restoration using directional regularization operator considering edges in four directions and the regularization operator with on direction for flat regions. We verified that the proposed method show better results in the suppression of the noise amplification in flat regions, and introduced less ringing artifacts in edge regions. As a result it showed visually better image and improved better ISNR further than the conventional methods.

• Investigative Magnetic Resonance Imaging
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• v.4 no.2
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• pp.120-127
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• 2000

Adaptive template filtering has been proposed recently for enhancement of signal-to-noise ratio without loss of resolution. In the adaptive template filtering, an optimal template among multiple templates is selected, then linear least square error filtering based on the template is applied in vowel by vowel basis. In some magnetic resonance imaging, where the distribution of gray level has relatively small dynamic range, e.g., $T_1$ imaging, however, artificial stair-like artifact is observed at near edges. This is partially due to the edge enhancement effect in such yokels that contain multiple compounds at the boundaries of tissues. The gray levels of these yokels become similar gray levels of near dominant vowels that contain single compound by the adaptive filtering, which enlarges edge discontinuities. In this paper, we propose a technique to eliminate such artifact by identifying those yokels that contain multiple compounds and assigning the largest template for them. Filtered images with the proposed technique show substantial visual enhancement at the edges without degradation of peak signal-to-noise ratio compared to the original adaptive template filtering for both magnetic resonance images and phantom images.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.06a
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• pp.107-110
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• 1996

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.188-195
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• 2004

We have analyzed the performance of TCP in the CDMA mobile communications systems with the adaptive modulation and coding(AMC). The wireless channel using AMC is characterized with not high error rate but highly varying bandwidth. Due to time-varying bandwidth, timeout events of TCP occurs more frequently, which leads to the throughput degradation. The analysis model is composed of the two parts. In the first part, we divide TCP packet stream into ‘packet groups’and derive the probability distribution of the wireless transmission time of each Packet group that reflects the time varying characteristics of AMC. In the second part, we formulate embedded Markov chain by making use of the results of the first part to model TCP timer mechanism and wireless transmission. Since our system model is characterized by the forward link high speed data transmission using AMC, the results reported in this paper can be used as a guideline for the design and operation of HSDPA, 1xEV-DO, and 1xEV-DV.

• Journal of The Korean Association For Science Education
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• v.42 no.6
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• pp.567-578
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• 2022

In this study, we examine whether the description of the elementary science curriculum guide, the concept of evolution, and the beliefs of teachers affect the teaching practice in classes related to adaptation of elementary school teachers. First, we examined the alternative concept among the sentences described in the bio-adaptation-related unit of the 2009 Elementary Science Curriculum Teacher's Guide and identified the effects of this description on the teaching practice of elementary school teachers. Next, six elementary school teachers were classified according to the results of the evolutionary concept test paper and the evolutionary belief test paper, and based on the class recording data and interview data, whether there is a difference in teaching execution. As a result, it was confirmed that there were a total of 18 descriptions corresponding to the concept of evolutionary alternatives in the analysis of instruction descriptions, and that these descriptions influenced elementary school teachers' adaptation concepts and teaching practice. Next, the group with high and low levels of evolution differ in the areas of "recognition of importance in the unit, distinction between adaptation concepts in the general sense and adaptation concepts in the biological sense, errors in the class," and "recognition of evolutionary education needs in the elementary curriculum." This study is meaningful in that it qualitatively confirms the research on the evolution concept of elementary school teachers, which has been approached quantitatively, and in-depth, confirms how the description, evolution concepts, and evolutionary beliefs affect elementary school teachers' biological adaptation concepts.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.175-177
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• 2006

소프트웨어는 많은 상황을 염두에 두고 만들어진다. 하지만 모든 문제를 해결하도록 만들 수는 없기 때문에 문제가 발생했을 때 그 문제를 해결할 수 있도록 적응성을 두어야 한다. 본 논문에서 제시하는 아키텍처는 WSAS, 컴포넌트 변환, 적응성을 위한 부분으로 구성된다. WSAS는 기존의 UDDI를 변경하지 않고 확장된 검색을 지원하는 서비스이다. 그리고 컴포넌트 서비스를 위한 컴포넌트 저장소를 제공한다. 변환 아키텍처는 검색된 서비스를 통해 컴포넌트를 변환하고 변환된 컴포넌트는 적응형 아키텍처에서 재구성을 통해 문제를 해결한다. 본 논문에서는 컴포넌트 기반의 아키텍처에 적응성을 위해 개선된 웹 서비스 발견 기법을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.9A
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• pp.1492-1498
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• 2001

DS-CDMA 시스템에서 다중 사용자간섭에 의한 성능 저하를 방지하기 위하여 비교적 구조가 간단하고, 성능이 우수한 병렬 간섭제거기가 이용된다. 본 논문에서는 병렬간섭제거기에 이용되는 기존 검파기의 파라미터의 최적화를 통하여 적응 병렬간섭제거기의 성능을 분석하고, 새로운 시험검파기인 HTNZ 검파방식을 제안한다. 적응 병렬간섭제거기는 기존의 부분 병렬간섭제거기에서 사용하는 고정된 값의 가중치를 NLMS 적응 알고리즘을 이용하여 적응적으로 계산하는 방법을 사용하였다. 시뮬레이션 결과 제안하는 방법이 기존의 hard 검파방식에 비해 사용자 용량이 57% 증가하는 향상된 결과를 얻었다.

• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.274-292
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• 2011

This paper proposes an efficient coding method of the depth-map which is different from the natural images. The depth-map are so smooth in both inner parts of the objects and background, but it has sharp edges on the object-boundaries like a cliff. In addition, when a depth-map block is decomposed into bit planes, the characteristic of perfect matching or inverted matching between bit planes often occurs on the object-boundaries. Therefore, the proposed depth-map coding scheme is designed to have the bit-plane unit coding method using the adaptive XOR method for efficiently coding the depth-map images on the object-boundary areas, as well as the conventional DCT-based coding scheme (for example, H.264/AVC) for efficiently coding the inside area images of the objects or the background depth-map images. The experimental results show that the proposed algorithm improves the average bit-rate savings as 11.8 % ~ 20.8% and the average PSNR (Peak Signal-to-Noise Ratio) gains as 0.9 dB ~ 1.5 dB in comparison with the H.264/AVC coding scheme. And the proposed algorithm improves the average bit-rate savings as 7.7 % ~ 12.2 % and the average PSNR gains as 0.5 dB ~ 0.8 dB in comparison with the adaptive block-based depth-map coding scheme. It can be confirmed that the proposed method improves the subjective quality of synthesized image using the decoded depth-map in comparison with the H.264/AVC coding scheme. And the subjective quality of the proposed method was similar to the subjective quality of the adaptive block-based depth-map coding scheme.

• Journal of the Korea Convergence Society
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• v.7 no.1
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• pp.183-188
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• 2016

The purposes of this study are to analyze how effects of parental attitudes, Sense of Community on adolescents school adjustment and verified was the mediating effect of Sense of Community between parenting attitudes and adolescents school adjustment. For data analysis, we have use the first year data for the 1st year middle schol students from 'the Korean Children and Youth Panel Survey, conducted in 2010' by the National Youth Policy Institute. The study shows that parenting attitudes and Sense of Community have a significant effect on adolescents school adjustment. And, the Sense of Community have a significant partial mediating effect among on parental attitudes and school adjustment. Thus, efforts to foster individual's Sense of Community and develop desirable parenting attitudes should be made to enhance the level of school adjustment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.8
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• pp.676-683
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• 2016

In this paper, an adaptive nulling algorithm which can be used to form nulls in the direction of jammer or interference signals in array antennas of single port system is proposed. The proposed adaptive algorithm does not require a priori knowledge of the incoming signal direction and can be applied to the partially adaptive arrays. This algorithm is the combination of the PSO(Particle Swam Optimization) algorithm and the gradient-based perturbation adaptive algorithm, which shows stable nulling performance adaptively even on the moving jammer environment where the incident direction of the interference signal is changing with time.