• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.99-108
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• 2008

For video compression, we have to consider two performance factors that are the search speed and coded video's quality. In this paper, we propose an enhanced fast block matching algorithm using the spatial correlation of the video sequence and the center-biased characteristic of motion vectors(MV). The proposed algorithm first finds a predicted motion vector from the adjacent macro blocks of the current frame and determines an exact motion vector using the cross pattern and a flat hexagon search pattern. From the performance evaluations, we can see that our algorithm outperforms both the hexagon-based search(HEXBS) and the cross-hexagon search(CHS) algorithms in terms of the search speed and coded video's quality. Using our algorithm, we can improve the search speed by up to 31%, and also increase the PSNR(Peak Signal Noise Ratio) by at most 0.5 dB, thereby improving the video quality.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.4
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• pp.129-133
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• 2015

In this paper, we propose a fast motion estimation algorithm which is important in the performance of video encoding. Conventional fast motion estimation algorithms have serious problems of low prediction quality in some frames and still much computation. In the paper, we propose an algorithm that reduces unnecessary computations only, while keeping prediction quality almost similar to that of the full search. The proposed algorithm uses distribution of probability of motion vectors, divides search range into several groups according to its importance, and applies adaptive block matching criteria for each group of search range. The proposed algorithm takes only 3~5% in computational amount and has decreased prediction quality about 0~0.01dB compared with the fast full search algorithm.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1113-1120
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• 2016

The purpose of this study is to find the important travel agency service quality factors in relation to the amount of information search efforts through major information channels of customers such as interpersonal source, retailer source, and external media source. Factor analysis using varimax rotation was performed and 20 service attributes of travel agent was reduced to 6 factors; convenience system, personal service, customer maintaining service, reputation, atmosphere and accessibility. According to MANOVA analysis there are significant differences in the service quality factor due to the type of source and amount of efforts of information search.

• Journal of the Korea Computer Graphics Society
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• v.6 no.3
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• pp.35-40
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• 2000

There are two problems in H.26X compression technique. One is compressing time in encoding process and the other is degradation of the decoded video quality due to high compression rate. For transferring moving pictures in real-time, it is required to adopt massively high compression. In this case, there are a lot of losses of an original video data and that results in degradation of quality. Especially degradation called by blocking artifact may be produced. The blocking artifact effect is produced by DCT-based coding techniques because they operate without considering correlation between pixels in block boundaries. So it represents discontinuity between adjacent blocks. This paper describes methods of quality compensation for H.26x decoded data and enhancing encoding speed for real-time operation. Our goal of the quality compensation is not to make the decoded video identical to a original video but to make it perceived better through human eyes. We suggest an algorithm that reduces block artifact and clears decoded video in decoder. To enhance encoding speed, we adopt new four-step search algorithm. As shown in the experimental result, the quality compensation provides better video quality because of reducing blocking artifact. And then new four-step search algorithm with $MMX^{TM}$ implementation improves encoding speed from 2.5 fps to 17 fps.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1219-1223
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• 2010

This paper proposes a fast motion estimation algorithm based on motion speed and multiple initial center points. The proposed method predicts initial search points by means of the spatio-temporal neighboring motion vectors. A dynamic search pattern based on the motion speed and the predicted initial center points is proposed to quickly obtain the motion vector. Due to the usage of the spatio-temporal information and the dynamic search pattern, the proposed method greatly accelerates the search speed while keeping a good predicted image quality. Experimental results show that the proposed method has a good predicted image quality in terms of PSNR with less searching time comparing with the Full Search, New Three-Step Search, and Four-Step Search.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.3
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• pp.133-144
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• 2014

Naver, a leading search engine in South Korea, may show modified and reorganized search results for some trendy and popular keywords; when popular words such as the titles of soap operas and films are searched for,all the detailed and well-organized information regarding them can be presented. By recognizing that search engines may modify and reorganize search results for some popular keywords, we mathematically model the impact of the degree of modification of search results on the search engine's profit to derive its optimal modification degree. We show how the optimal degree of search result modification may change according to the different shapes of the search engine's advertising revenue function.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.17-22
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• 2022

Due to the recent advances in high-speed communication technologies as well as the easy production of high-quality video contents, IPTV is becoming increasingly popular. Meanwhile, as the number of IPTV channels increases, channel search time to find the desired channel keeps increasing. In this paper, we discuss how to improve the channel search latency in IPTV, and introduce caching and prefetching techniques that are widely used in memory management systems. Specifically, we adopt memory replacement, prefetching, and caching techniques in IPTV channel search interfaces and show the effectiveness of these techniques as the number of channels are varied.

• Clinics in Shoulder and Elbow
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• v.26 no.3
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• pp.238-244
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• 2023

Background: Many patients use online resources to educate themselves on surgical procedures and make well-informed healthcare decisions. The aim of our study was to evaluate the quality and readability of online resources exploring shoulder arthroplasty. Methods: An internet search pertaining to shoulder arthroplasty (partial, anatomic, and reverse) was conducted using the three most popular online search engines. The top 25 results generated from each term in each search engine were included. Webpages were excluded if they were duplicates, advertised by search engines, subpages of other pages, required payments or subscription, or were irrelevant to our scope. Webpages were classified into different source categories. Quality of information was assessed by HONcode certification, Journal of the American Medical Association (JAMA) criteria, and DISCERN benchmark criteria. Webpage readability was assessed using the Flesch reading ease score (FRES). Results: Our final dataset included 125 web pages. Academic sources were the most common with 45 web pages (36.0%) followed by physician/private practice with 39 web pages (31.2%). The mean JAMA and DISCERN scores for all web pages were 1.96±1.31 and 51.4±10.7, respectively. The total mean FRES score was 44.0±11.0. Only nine web pages (7.2%) were HONcode certified. Websites specified for healthcare professionals had the highest JAMA and DISCERN scores with means of 2.92±0.90 and 57.96±8.91, respectively (P<0.001). HONcode-certified webpages had higher quality and readability scores than other web pages. Conclusions: Web-based patient resources for shoulder arthroplasty information did not show high-quality scores and easy readability. When presenting medical information, sources should maintain a balance between readability and quality and should seek HONcode certification as it helps establish the reliability and accessibility of the presented information. Level of evidence: IV.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.3
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• pp.409-428
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• 1995

Job shop scheduling with m different machines and n different jobs is a NP-hard problem of combinatorial optimization. The purpose of the paper is to develop the heuristic method using tabu search for job shop scheduling to minimize makespan or mean flowtime. To apply tabu search to job shop scheduling problem, in this paper we propose the several move methods that employ insert moves in order to generate the neighbor solutions, and present the efficient rescheduling procedure that yields active schedule for a changed operation sequence by a move of operations. We also discuss the tabu search techniques of diversifying the search of solution space as well as the simple tabu search. By experiments, we find the appropriate tabu list size and tabu attributes, and analyze the proposed tabu search techniques with respect to the quality of solutions and the efforts of computation. The experimental results show that the proposed tabu search techniques using long-term memory function have the ability to search a good solution, and are more efficient in the mean flowtime minimization problem than in the makespan minimization.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06c
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• pp.214-217
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• 1994

The major drawback in the Code Excited Linear Prediction type vocoders is their large computational requirements. In this paper, a simple method is proposed to reduce the pitch searching time in the pitch filter almost without degradation of quality. On the basis of the observational regularity of the correlation function of speech, only the limited numbers of pitch lags are considered to be an optimum pitch. This is done by skipping the negative envelope side of the correlation function and limiting the maximum number of lags to be considered preliminarily. By doing so, we can reduce the computational time of pitch searching more than 51% with negligible quality degradation. In addition to that, by combining that method with the conventional delta search technique, we can reduce the computational time requirements more than 60% without serious lowering the speech quality in segmental SNR measure compared to the conventional full search method.