• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.8
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• pp.1257-1264
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• 2017

In video content watching service, when a user requests video content, the content server has to transmit the entire video to the client for watching. This transmission delay increases as the size of video content increases. In order to solve the transmission delay problem, a prefetching technique can be used in which a video content to be watched by a user is predicted and transmitted to a client before the user requests it. In this paper, we propose a prefetching system considering multiple indices for video content. In the proposed method, video content to be prefetched is selected by comprehensively analyzing the order relation index indicating the order of viewing the videos of the users, the similarity index between the video contents, and the popularity index reflecting the viewing frequency of the video content. Experimental results show that the maximum accuracy is achieved when prefetching uses only the order relation index for movie contents.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.11
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• pp.5731-5754
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• 2019

In this paper, we redesign, implement, and evaluate ShareSafe (Based on SecGraph), an open-source secure graph data sharing/publishing platform. Within ShareSafe, we propose De-anonymization Quantification Module and Recommendation Module. Besides, we model the attackers' background knowledge and evaluate the relation between graph data privacy and the structure of the graph. To the best of our knowledge, ShareSafe is the first platform that enables users to perform data perturbation, utility evaluation, De-A evaluation, and Privacy Quantification. Leveraging ShareSafe, we conduct a more comprehensive and advanced utility and privacy evaluation. The results demonstrate that (1) The risk of privacy leakage of anonymized graph increases with the attackers' background knowledge. (2) For a successful de-anonymization attack, the seed mapping, even relatively small, plays a much more important role than the auxiliary graph. (3) The structure of graph has a fundamental and significant effect on the utility and privacy of the graph. (4) There is no optimal anonymization/de-anonymization algorithm. For different environment, the performance of each algorithm varies from each other.

• Journal of Internet Computing and Services
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• v.10 no.1
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• pp.111-121
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• 2009

In this paper, we propose a multimedia recommender system using user's playback time. Proposed system collects multimedia content which is requested by user and its user‘s playback time, as web log data. The system predicts playback time.based preference level and related contents from collected transaction database by fuzzy association rule mining. Proposed method has a merit which sorts recommendation list according to preference without user’s custom preference data, and prevents a false preference. As an experimental result, we confirm that proposed system discovers useful rules and applies them to recommender system from a transaction which doesn‘t include custom preferences.

• Journal of the Korean Society of Marine Environment & Safety
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• v.1 no.1
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• pp.9-25
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• 1995

Although the studies carried out in recent years have provied much new information about channel widths and alignment, they are not consistent in their results. In addition, as a result of variations in local condition and type of traffic accommodated, the dimensions of the channel widths vary over a wide range. Therefore, the recommendation made by the maritime engineering organizations over the world, do not offer detailed and decisive optimal design criteria and are all different. It, therefore, was attempted in this paper to draw a decisive guideline on the optimal widths and alignment of the navigational channels, which can be utilized by the port designers at the stage of the planning. The guideline was drawn through the comparison and analysis of the existing guidelines of the U.S.A, Japan and PIANC and simulation experiment. The simulation experiment was carried out using the "Off Line Port and Waterway Design Simulator" to find the optimal dimensions of the widths of the navigational channels. 90 different simulation runs were conducted at the 3 different secenario channels. New guidelines, the result of the study, is expected to be used usefully by the Korean port designers when designing the rapodly developing ports in Korea. in Korea.

• Steel and Composite Structures
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• v.14 no.2
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• pp.173-190
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• 2013

The major objective of this paper is to evaluate the behavior and ultimate resisting capacity of circular CFT columns. To consider the confinement effect, proper material models with respect to the confinement pressure are selected. A fiber section approach is adopted to simulate the nonlinear stress distribution along the section depth. Material nonlinearity due to the cracking of concrete and the yielding of the surrounding steel tube, as well as geometric nonlinearity due to the P-${\Delta}$ effect, are taken into account. The validity of the proposed numerical analysis model is established by comparing the analytical predictions with the results from previous experimental studies about pure bending and eccentric axial loading. Numerical predictions using an unconfined material model were also compared to investigate the confinement effects on various loading combinations. The ultimate resisting capacities predicted by the proposed numerical model and the design guidelines in Eurocode 4 are compared to evaluate the existing design recommendation.

• Earthquakes and Structures
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• v.11 no.3
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• pp.387-406
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• 2016

The main purpose of this paper is to determine the dynamic characteristics and the structural stability of the two approach viaducts of the Bosphorus Suspension Bridge under the expected stresses that would be caused during earthquake conditions. The Ortakoy and the Beylerbeyi approach viaducts constitute the side spans of the bridge at two locations. The bridge's main span over the Bosphorus is suspended, whereas they are supported at the base at either end. For the numerical investigation of the viaducts, 3-D computational structural finite element-FE models were developed. Their natural frequencies and the corresponding mode shapes were obtained, analyzed, presented and compared. The performances of the viaducts, under earthquake conditions, were studied considering the P-Delta effects implementing the push-over (POA) and the non-linear time-history analyses (NTHA). For the NTHA, three earthquake ground motions were generated depending on the location of the bridge. Seismic performances of the viaducts were determined in accordance with the requirements of the Turkish Seismic Code for the Earthquake Design of Railways Bridges (TSC-R/2008) and those of Caltrans (CALTRANS-2001) given for Seismic Design of Steel Bridges, separately. Furthermore, the investigation was extended for evaluating the possible need for retrofitting in the future. After the analysis of the resultant data, a retrofit recommendation for the viaducts was presented.

• Women's Health Nursing
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• v.11 no.1
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• pp.5-11
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• 2005

Breast feeding can play a very important role in the development of strong, healthy children. Many studies over the years have shown that breast milk provides defense against common ailments of childhood such as otitis media, gastrointestinal distress, and atopic diseases (allergies). For these reasons the American Academy of Pediatrics recommends breast feeding for at least the first twelve months of an infant's life. Goals of the Health People 2010 Initiative include that at least 75% of mothers will be breast feeding upon discharge from the hospital and at least 50% will be still nursing at six months post-partum. Currently, about 60% of new mothers initiate breast feeding and about 26% are still breast feeding at six months. However, research has shown that breast feeding trends are below these averages in rural areas of the United States. This may be due in part to lack of breast feeding knowledge and teaching in rural areas. Rural hospitals and birthing centers have not initiated many of the breast feeding promotional programs, such as the Baby Friendly Hospital Initiative and Best Start, that have been successful in improving breast feeding trends in urban areas. Often new mothers who live in rural areas do not have access to a lactation consultant to help them with proper follow up. This paper will examine these concerns and propose recommendations to improve breast feeding in rural areas.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.416-423
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• 2009

From marketing perspectives, WOM(Word-of-Mouth) is one of the communication methods for travelers. It can be an instrument of the effect on tourist decision. The growing predominance of internet use has further highlighted the need for understanding of UCC(User-created contents) tourism information such as travel experience and travel recommendation. This paper was to examine usage patterns of UCC tourism information using experimental design and contents analysis. The result indicated that there were qualities of UCC tourism information. That is useful implication to tourism information-related marketers in destination marketing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1383-1391
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• 1999

This paper presents a rate control method that minimizes global distortion under given target bit rates for video communication. This method makes the quality of reconstructed images better than that of the conventional ones based on R-D model at the same bit rates. Given a set of quantizers, a sequence of macroblocks to be quantized selects the optimal quantizer for each macroblock so that the total cost measure is minimized and the finite buffer is never in overflow. To solve this problem we provide a heuristic algorithm based on Lagrangian optimization using an operational rate-distortion framework and a quantization method follows H.263recommendation.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.2
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• pp.232-236
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• 2010

Nowadays, mobile users have a huge amount of multimedia contents and can use these contents anytime, anywhere by advance in computer and network techniques. However, users spend too much time for searching and managing these contents in web and local file system. Expecially, small and uncomfortable user interfaces of mobile devices make it difficult to search and manage multimedia contents. Therefore, an intelligent multimedia contents management technique is needed to use these contents more efficiently. In this paper, we propose a Personalized Mobile Multimedia Contents Provider (PMMCP) System which provides personalized multimedia contents based on users' psychological patterns and situations.