• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.7
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• pp.398-400
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• 2014

In this letter, we propose a cross-layer technique jointly considering modulation coding schemes (MCSs) of medium access control (MAC) layer, source significance information (SSI) and error concealment unit of application (APP) layer, and channel quality information (CQI) of physical (PHY) layer. We demonstrate the improved video quality by the proposed technique when H.264 videos are streamed over Rayleigh fading wireless channels.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.71-75
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• 1998

압축된 비디오 신호를 전송함에 있어 에러에 의해 영상이 손상되는 영향을 최소화하기 위하여 여러 가지 오류은닉 기법들이 제안되고 있다. 본 논문에서는 인터 프레임에서 오류가 발생하여 정보가 손실되었을 경우, 움직임벡터의 효율적인 복구를 통한 오류은닉 방식을 제안하였다. 이를 위해 기존의 블록오류은닉 방식이 갖고 있는 문제점들을 살펴보고 이 중 전체 합 문제(total sum problem)에 대해 해결책으로 제시 될 수 있는 Infinite Norm을 이용한 블록경계정합방식을 제안하였고 실험에 의해 그 성능을 검증하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.366-367
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• 2015

최근 악성코드의 유포 동향을 살펴보면 APT 공격이 많다. 본 논문에서는 악성코드 은닉사이트를 통하여 악성코드가 유포되는 과정과 그 과정에서 공격자가 침투하는 경로나 대표적인 취약점들에 대하여 설명하고 그에 대한 대응책에 대하여 논하고자 한다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.6
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• pp.641-651
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• 2002

Recently, many advanced video application services over the mobile wireless networks have required a transcoder which can efficiently reduce the size of compressed video bitstreams. The transcoder can be worked in either the spatial domain or the DCT domain. In this paper, we propose a new fast hybrid-type transcoder which can efficiently reduce the frame size with keeping the visual quality. The proposed scheme consists of two major processes: a transform domain process and a spatial domain process. We also propose a scheme for coding mode selection and motion vector refinement. Experimental results show that our approach can reduce the computational complexity more than any other conventional spatial-domain transcoder with keeping the visual quality.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.167-175
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• 2000

Compressed bitstreams generated by an MPEG-2 video encoder (or digital TV picture transmission are quite sensitive to channel errors. Due to the coding structure of the MPEG-2 video compression algorithm, a single bit error can affect not only the current Picture frame but also succeeding frames. Error concealment algorithms attempt to repair damaged portions of the picture by exploiting spatial and temporal redundancies in the correctly received and reconstructed video frames. In this paper, we analyze the effect of channel errors in MPEG-2 video bitstreams and estimate lost motion vectors by exploiting temporal redundancies in the video frames. Motion vectors can be estimated from the vertically adjacent extended region of lost macroblocks. Finally, we conceal the damaged macroblocks by compensating the displacement with the estimated motion vectors. Simulation results demonstrate that both the weighted sum algorithm and the extension matching algorithm achieve good performance in terms of PSNR values as well as subjective image quality.

• Journal of the Korean Society of Costume
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• v.56 no.5 s.104
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• pp.132-149
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• 2006

The purpose of this study was to establish the theoretical view for the analysis of the aesthetic characteristics of dress from the viewpoint of oriental aesthetics. Also, this study examined the universality and particularity of aesthetic characteristics in Korean and Japanese women's traditional costumes. To establish the theoretical view for the aesthetic analysis of dress from the viewpoint of oriental aesthetics, this study examined the relationship between the internal spirit of human, culture and the external form of dress. Based on this consideration, the viewpoints for the analysis of dress formation were the 'Form' as the basic structure of the external formation of dress and 'the Ornamentation' as the emphasis of the artistic characteristics of dress. The common world view shared by Korea and Japan holds the thinking system that everything is created from 'not to bee(無)' to 'being(有)'. This view emphasizes the totality and circulation of energy called 'Ki(氣)'. According to this view, oriental culture has been developed by intuition and pleasure called 'Heung(興)'. Therefore, the form of the oriental culture includes ambiguity and emphasizes the total harmony. These characteristics appeared in dress as the design of ambiguity, asymmetry and concealment. The meaning of the ornamentation in oriental world was the unified harmony of diversity and the colors and patterns of oriental dress were used by the symbolic meaning of Yin-Yang & Wu-Shing (陰陽五行)s principles. On the basis of the world view of the Ki, Korean and Japanese women's traditional costumes commonly shared the aesthetic values of concealment, emptiness, and symbolism. Also, their costumes expressed the difference, especially in the ornamentation. Korean costume expressed the beauty of simplicity and naivety, and Japanese costume expressed the beauty of ornamentation and nonornamentatIon.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.20-29
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• 2013

The compression of video data is intended for real-time transmission of band-limited channels. Compressed video bit-streams are very sensitive to transmission error. If we lose packets or receive them with errors during transmission, not only the current frame will be corrupted, but also the error will propagate to succeeding frames due to the spatio-temporal predictive coding structure of sequences. Error detection and concealment is a good approach to reduce the bad influence on the reconstructed visual quality. To increase concealment efficiency, we need to get some more accurate error detection algorithm. In this paper, We hide specific data into the motion vector difference of each macro-block, which is obtained from the procedure of inter prediction mode in H.264/AVC. Then, the location of errors can be detected easily by checking transmitted specific data in decoder. We verified that the proposed algorithm generates good performances in PSNR and subjective visual quality through the computer simulation by H.324M mobile simulation tool.

• The Journal of the Korea Contents Association
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• v.6 no.10
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• pp.107-113
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• 2006

Error Concealment method for Intra frames in H.264 reconstructs the lost block by computing weighted average value of the boundary pixels of the neighboring blocks; up, bottom, left and right blocks. However a simple average of pixel values of the neighboring blocks for Intra frames in H.264 leads to excessive blurring and degrades the picture quality severely. To solve this problem, in this paper we estimate the dominant edge of lost block using the pixel values of the neighboring blocks and reconstruct the pixel values by choosing adaptive interpolation between directional interpolation and weighted average interpolation considering the result value of the interference function based on statistics. Finally directional interpolation method improves by determining the dominant edge direction considering the relation of the dominent edge and the edges of neighboring blocks. Experiments show improvement of picture quality of about $0.5{\sim}2.0dB$ compared with the method of H.264.

• Journal of Haehwa Medicine
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• v.24 no.1
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• pp.25-36
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• 2015

Objective : This study aims to evaluate a risk of bias by Risk of Bias tool and RoBANS(Risk of Bias Assessment tool for Non-randomized Study) tool for clinical trial papers proving treatment effect of herbs to alopecia and provides the newest reason of effectiveness of herbs to alopecia. Methos : Data were collected through electronic database including NDSL, KISS, KMBASE, Koreantk, OASIS, KoreaMed, KISTI, Pubmd, Cochrane CENTRAL and CINAHL. Two experts in Oriental Medince assessed risk of bias of randomized controlled trials by Cochrane group's Risk of Bias tool and non-randomized controlled trials by RoBANS tool after searching, reviewing and selecting papers. Results : Total number of selected trials is 20 including 4 randomized controlled trials, 13 non-randomized controlled trials and 3 case reports. This study evaluates the risk of bias of 17 papers including 4 randomized controlled trials and 13 non-randomized controlled trials except 3 case reports by risk of bias tool and RoBANS tool. All papers of randomized controlled trials are evaluated unclear for random sequence generation and allocation concealment as there are no word on them. And all papers of non-randomized controlled trials are evaluated unclear for blinding of outcome assessments and relatively low for others. Conclusion : We must try to specify concretely methods of allocation concealment after planning and practicing it for reducing a selection bias in randomized controlled trials. Also report a reason of missing value and blinding outcome assessments. And we have to agonize and mention methods of blinding of researchers for reducing a detection bias in non-randomized controlled trials.

• Journal of the Korean Society of Costume
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• v.57 no.1 s.110
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• pp.105-117
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• 2007

The purpose of this study is to help the understanding the characteristics in the costumes of men and women throughout the overall acceptance process of 'Naewaebub' in the late 'Chosun Dynasty' in which the notion of 'Naewae' is more prosperous than any other period in Korean history. Originally the distinction between man and woman was not intended to display the high and the low but to show the mutual respect according to each duty. As time goes on, that ideal became gradually changed to heighten the man and lower the women especially in 'Han' period of China. There was the ideal of distinction in the ancient times in Korea. Until 'Koryo Dinasty' the community has the system of blood-tied that put together maternal and paternal. 'Karye' was introduced in the late 'Koryo Dynasty' and accepted to the stereotype of morale in the 'Chosun Dynasty' and there seemed to be 'Samgang' and 'Oryun' at once. Many restrictions was imposed to behavior in women like rules of prohibition in attending the temple and concealment of woman's face and was recognized to rule of distinction between man and woman. Confucian life custom has been settled to Korean society throughout the late 16th century and 17th century and there were some appearances in the housing construction which divide the residences of man and woman. The characteristics in the costume from the avoidance of opposite sexes are clear in the structure of clothes changed from similar style to different style. The examples of those characteristics are as fellows. The costume in man was developed to advanced 'Pyoun-bokkwan' and 'Pyounbokpo' as social action of man prospered. Meanwhile the trousers which had been the same in the man and woman were separated to different trousers between man and woman. The costume life style of woman was changed to using the a hair whirl, hiding the face in the street and overlapping the innerwear under the skirt which was extension of woman's closed life style in late 'Chosun Dynasty'.