• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2319-2337
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• 2019

In this paper, we study the distributed cooperative caching for Internet content providers in a small cell of heterogeneous network (HetNet). A general framework based on bankruptcy game model is put forth for finding the optimal caching policy. In this framework, the small cell and different content providers are modeled as bankrupt company and players, respectively. By introducing strategic decisions into the bankruptcy game, we propose a caching value assessment algorithm based on analytic hierarchy process in the framework of bankruptcy game theory to optimize the caching strategy and increase cache hit ratio. Our analysis shows that resource utilization can be improved through cooperative sharing while considering content providers' satisfaction. When the cache value is measured by multiple factors, not just popularity, the cache hit rate for user access is also increased. Simulation results show that our approach can improve the cache hit rate while ensuring the fairness of the distribution.

• Journal of Information Processing Systems
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• v.18 no.6
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• pp.803-812
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• 2022

With the increasing number of mobile device users worldwide, utilizing mobile edge computing (MEC) devices close to users for content caching can reduce transmission latency than receiving content from a server or cloud. However, because MEC has limited storage capacity, it is necessary to determine the content types and sizes to be cached. In this study, we investigate a caching strategy that increases the hit ratio from small base stations (SBSs) for mobile users in a heterogeneous network consisting of one macro base station (MBS) and multiple SBSs. If there are several SBSs that users can access, the hit ratio can be improved by reducing duplicate content and increasing the diversity of content in SBSs. We propose a Deep Q-Network (DQN)-based caching strategy that considers time-varying content popularity and content redundancy in multiple SBSs. Content is stored in the SBS in a divided form using maximum distance separable (MDS) codes to enhance the diversity of the content. Experiments in various environments show that the proposed caching strategy outperforms the other methods in terms of hit ratio.

• Food Science and Preservation
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• v.18 no.6
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• pp.1002-1008
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• 2011

This study aimed to examine the effect of the Schizandra chinensis fruit and Morus alba leaf on insulin expression in HIT-T15 cells, which is exposed by glucose. The total polyphenol contents of the S. chinensis fruit ethanol extract and the M. alba leaf hot-water extract were $20.11{\pm}0.35$ mg/g and $50.02{\pm}0.62$ mg/mL, respectively. The S. chinensis fruit ethanol extract and the M. alba leaf hot-water extract contained $2.85{\pm}0.15$ and $8.76{\pm}0.43$ mg/g flavonoids, respectively. The antioxidant ability of the M. alba leaf hot-water extract was found to be superior to that of the S. chinensis fruit ethanol extract. Compared to the HIT-T15-treated 10 mM 2-deoxy-D-glucose, the $100{\mu}g/mL$ S. chinensis ethanol extract was found to have a two fold increase in insulin productivity. Moreover, the $100{\mu}g/mL$ M. alba leaf hot-water extract promoted the insulin secretion of high-glucose-damaged HIT-T15 almost ten fold. The above results showed that the S. chinensis fruit ethanol extract and M. alba leaf hot-water extract may improve the insulin productivity of the beta cell with glucose-induced oxidative damage. These data suggest that the S. chinensis fruit ethanol extract and the M. alba leaf hot-water extract can be used as food materials for the regulation of insulin secretion.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.35-48
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• 2018

The study of air defense against North Korean tactical ballistic missiles (TBM) should consider the rapidly changing battlefield environment. The study for target re-designation for intercept missiles enables effective operation of friendly defensive assets as well as responses to dynamic battlefield. The researches that have been conducted so far do not represent real-time dynamic battlefield situation because the hit probability for the TBM, which plays an important role in the decision making process, is fixed. Therefore, this study proposes a target re-designation algorithm that makes decision based on hit probability which considers real-time field environment. The proposed method contains a trajectory prediction model that predicts the expected trajectory of the TBM from the current position and velocity information by using random forest and moving window. The predicted hit probability can be calculated through the trajectory prediction model and the simulator of the intercept missile, and the calculated hit probability becomes the decision criterion of the target re-designation algorithm for the missile. In the experiment, the validity of the methodology used in the TBM trajectory prediction model was verified and the superiority of using the hit probability through the proposed model in the target re-designation decision making process was validated.

• Journal of Acupuncture Research
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• v.29 no.5
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• pp.61-74
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• 2012

Objectives : This study is perfomed for preparation of oriental medicine clinical guidelines for drawing up the standards of oriental medicine demonstration and diagnosis classification about the knee pain. Methods : Statistical analysis about Crane's-knee wind(鶴膝風), arthralgia syndrome(痺症), knee injury(膝傷), gout arthritis(痛風), Youk jeol poung(歷節風) classified experts' opinions about knee pain patients by Delphi method is conducted by using oriental medicine diagnosis questionnaire. The result was classified by using linear discriminant analysis(LDA), diagonal linear discriminant analysis(DLDA), diagonal quadratic discriminant analysis(DQDA), K-nearest neighbor classification(KNN), classification and regression trees(CART), support vector machines(SVM). Results : The results are summarized as follows. 1. The result analyzed by using LDA has a hit rate of 81.65% in comparison with the original diagnosis. 2. The result analyzed by using DLDA has a hit rate of 63.3% in comparison with the original diagnosis. 3. The result analyzed by using DQDA has a hit rate of 65.14% in comparison with the original diagnosis. 4. The result analyzed by using KNN has a hit rate of 74.31% in comparison with the original diagnosis. 5. The result analyzed by using CART has a hit rate of 75.23% in comparison with the original diagnosis when the test of selected 13 significant questions based on analysis of variance was performed. 6. The result analyzed by using SVM has a hit rate of 87.16% in comparison with the original diagnosis. Conclusions : Statistical analysis using oriental medicine diagnosis questionnaire on knee pain generally turned out to have a significant result.

• Korean journal of communication and information
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• v.51
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• pp.47-64
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• 2010

Korea film market is heterogeneously divided market that comes from competition between Korean movies and foreign imported movies. This research empirically analyzes genre differentiation in Korean film market with three dimensions (film audience preference, production and import, box office hit). The results indicate that, first, audiences who preferring Korean movie preferred 'cultural factor oriented genres', but audiences who preferring foreign movie preferred 'high budget oriented genres'. Second, imported foreign movie genre distribution was little bit different with box office hit genre of foreign movies. Foreign movie was imported not only hit genre (action genre) but also low cost genre (comedy and Drama/melodrama genre), but most of all Korean film was produced in box office hit genres (comedy and Drama/melodrama genre), third, Korean movies hit a box office in comedy and Drama/melodrama genre, but foreign movies hit a box office in action and SF/Fantasy genre. Those results show that Korea movies' genres are concentrated very much in cultural factor oriented genre. Those results can give implication of diversity policy and movie production strategy of Korea film market.

• Health Policy and Management
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• v.10 no.2
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• pp.1-21
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• 2000

This study reviewde various parametic and nonparametic method for forexasting hospital closures in Korea. We compared multivariate discriminant analysis, multivartiate logistic regression, classfication and regression tree, and neural network method based on hit ratio of each model for forecasting hospital closure. Like other studies in the literture, neural metwork analysis showed highest average hit ratio. For policy and business purposes, we combined the four analytical method and constructed a foreasting model that can be easily used to predict the probabolity of hospital closure given financial information of a hospital.

• International Journal of Contents
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• v.3 no.1
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• pp.14-18
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• 2007

General replacement policy includes document-based LRU or LFU technique and other various replacement policies are used to replace the documents within cache effectively. But, these replacement policies function only with regard to the time and frequency of document request, not considering the popularity of each web site. In this paper, we present the document replacement policies with regard to the popularity of each web site, which are suitable for modern network environments to enhance the hit-ratio and efficiently manage the contents of cache by effectively replacing documents on intermittent requests by new ones.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.3
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• pp.289-294
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• 2012

In this paper, the three-dimensional magnetic field created by non-periodic magnet arrays is calculated analytically. The analytical expression of the magnetic field is derived by using a magnetic charge model. The influence of ferromagnetic boundaries is formulated with an image method. Finally, we compare the results determined by analytical calculations to those from a finite element simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.106-108
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• 2004

링크 구조를 이용하는 대표적인 알고리즘인 HITS는 링크 정보를 이용하여 Authority와 Hub rating을 구하는 알고리즘이다. 그러나 HITS에서는 중요도와는 관계없이 단순히 링크만을 많이 갖는 page의 Authority와 Hub rating이 비정상적으로 높게 계산되는 문제점이 있어 이를 해결하기 위한 연구들이 있었다. 본 논문에서는 이러한 연구들의 결과를 개선시키기 위해 Authority와 Hub rating의 단순한 합이 아닌, 평균과 priority를 적용하였다. 정확도를 측정하는 실험을 통해 제안하는 알고리즘이 기존의 방법보다 우수한 성능을 나타냄을 알 수 있다.