• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.19-28
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• 2014

Recent advancements in the IT industry have made daily life more convenient than ever before. In particular, studies have focused on the position detection of individuals using the GPS in smartphones, and this application has been utilized actively in emergency rescue organizations. However, existing methods send the location information of a user to a predetermined guardian set by the user or to a control center when the user enters into or deviates from a predetermined space. Such spaces are created by an arbitrary radius, thereby making it difficult to set a detailed area by using an existing radius-area creation method in an unstructured space and path with a specific road, such as for trekking, amusement parks, or mountaineering. This study proposes a novel method for setting up an area by connecting multiple radii to improve the existing radius-area creation method in order to easily set a detailed area in smart devices or on the Internet. In addition, an optimization method for resource use is proposed by comparing the operation results in which a user's location is detected by using the proposed location-based area setup method and deviation detection.

• Korean Business Review
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• v.20 no.1
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• pp.145-168
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• 2007

Recommender system helps customers to find easily items and helps the e-biz companies to set easily their target customer by automated recommending process. Recommender systems are being adopted by several e-biz companies and from these systems, both of customers and companies take some benefits. This study sets several thresholds to the similarity weight, which indicates a degree of similarity of two customers' preference, to improve the performance of prediction accuracy. According to the threshold, the accuracy of prediction is being improved but some threshold setting shows the reduction of the prediction rate, which is the coverage. This coverage reduction has male effect on the prediction accuracy of customers, so more study on the prediction accuracy of recommender system and to maximize the coverage are needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.1-11
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• 2018

In various engineering fields, determining the appropriate parameter set is a cumbersome and difficult task when solving optimization problems. Despite the appropriate parameter setting through parameter sensitivity analysis, there are limits to evaluating whether the parameters are appropriate for all optimization problems. For this reason, kinds of a Self-adaptive Harmony searches have been developed to solve various engineering problems by the appropriate setting of algorithm's own parameters according to the problem. In this study, various types of Self-adaptive Harmony searches were investigated and the characteristics of optimization were categorized. Six algorithms with a differentiation of optimization process were applied and compared with not only the mathematical optimization problem, but also the engineering problem, which has been applied widely in the algorithm performance comparisons. The performance of each algorithm was compared, and the statistical performance indicators were used to evaluate the application results quantitatively.

• Journal of the Korean Geographical Society
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• v.39 no.3
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• pp.360-373
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• 2004

The purpose of this study is establishing how to build the area of local agents and regional offices in the oil company using GIS technique by reviewing on the spatial distribution pattern and characteristics of the sales area of oil products. Location-allocation and spatial interaction model are cooperated in order to establish sales area of petroleum products distribution system. Location-allocation model is used in the capital region where local agents are concentrated on like Kyoung-gi local agent. Spatial interaction model is used in the rest of the area in Korea to analyze the sales range of the regional offices in oil company. Each office made a big difference in registered cars and population because of the level of petroleum consumption in each sales area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1659-1664
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• 2011

Fuzzy C-Means (FCM) is one of the most widely used clustering algorithms and has been used in many applications successfully. However, FCM has some shortcomings and initial prototype selection is one of them. As FCM is only guaranteed to converge on a local optimum, different initial prototype results in different clustering. Therefore, much care should be given to the selection of initial prototype. In this paper, a new initialization method for FCM using kernel density estimation (KDE) is proposed to resolve the initialization problem. KDE can be used to estimate non-parametric data distribution and is useful in estimating local density. After KDE, in the proposed method, one initial point is placed at the most dense region and the density of that region is reduced. By iterating the process, initial prototype can be obtained. The initial prototype such obtained showed better result than the randomly selected one commonly used in FCM, which was demonstrated by experimental results.

• Journal of the Korean association of regional geographers
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• v.16 no.6
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• pp.673-688
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• 2010

The purpose of this study is to develop an optimization model for reconstructing local administrative districts using spatial analysis and modeling. For this, literature related to reorganization of local administrative systems was critically reviewed and criteria for redistricting were extracted. An optimization model for reconstructing administrative districts was formulated based on these criteria. The model considered three criteria; homogeneity within a reconstructed district, equity among reconstructed districts, and spatial arrangement. Homogeneity for relieving spatial mismatch between administrative and living(economic) boundaries is measured by spatial interaction within a district. Equity among districts is evaluated using population, area, and financial independence. Finally, spatial arrangement is measured by compactness and contiguity. The developed optimization model was implemented using Automated Zoning Procedure(AZP) in GIS environment and applied to a problem aggregating Si-Gun administrative units into broader districts. Application results demonstrate that the model can provide optimal districts according to alternative objective functions.

• The Journal of the Korea Contents Association
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• v.4 no.2
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• pp.68-75
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• 2004

In this paper, n study a distributed establishment scheme to setup lightpath in WDM/TDM Network considering user traffic characteristics. We propose a GBTA(guaranteed-bandwidth time-slot allocation) algorithm which assigns time-slots according to the requred traffic so that it can utilize given network resources efficiently in RWTA(routing and wavelength time-slot assignment) schemes. We consider traffic specification on the basis of ATM traffic classes. Also, in order to increase link utilization and minimize blocking probability, we extend distributed lightpath establishment protocol based on GBTA algorithm. In order to establish lightpath in distributed WDM/IDM network, we use backward resonation protocol that resewes resource with recent information. We use DOWTns(Distributed Optical WDM/TDM ns) that is extended from NS(Network Simulator), in order to verify proposed GBTA-based optical wavelength routed network.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.105-113
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• 2014

Most operating civil structures measure response data continuously by various types of sensors and evaluate their health conditions. Measurement control criteria for such civil structures are usually defined in the first operating stage by experts working at a construction or engineering company. However, a few studies have been carried to examine the adequacy of these measurement control criteria based on the actual measured data. The paper introduces a systematic way of resetting the measurement control criteria for the measured monitoring data based on the statistical aspects of the measured data. The proposed statistical approach has been examined with actually measured time-history data from a bridge structure.

• Journal of the Korean Society for Library and Information Science
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• v.40 no.4
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• pp.333-366
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• 2006

The purpose of this study is principle and theory of main class in a Library Classification. According to Sayers, 'The foundation of the library is the book; the foundation of librarianship is classification.' We looked at the between scientific and bibliographic classification, and at the fact that bibliographic scheme is usually an aspect classification. That is to say, the organization of topics is based on areas or activity and the first division of the scheme is into disciplines or subject domains. This first division of classification creates what are called main class. The sequence of main classes is also important. A rough definition of a amin class is that it corresponds to a sin91e notational character. Main classes usually equivalent to traditional disciplines. What constitutes a main class will vary from one classification to another. The order in which the main classes are listed is often discussed at the theoretical level, and some orders are considered to be better than others.

• Journal of Korean Society of Transportation
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• v.21 no.4
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• pp.29-44
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• 2003

A balanced evaluation system for a bus route network was proposed for a mid-sized suburban city. The evaluation system consists of 7 criteria-accessibility, riding comfort. transfer rate, directness of route, productivity of operation, regional equity, and minimum requirement of bus fleet - and quantitative indicators representing each of the criteria. The proposed system was applied in Siheung, a suburban city in Seoul Metropolitan Area. Four alternative scenarios of bus route network including the existing one were evaluated. The results showed that the suggested criteria and indicators are acceptable for the evaluation of a bus route network. In order to enhance the proposed evaluation procedure, further studies on the normalization of produced values and weights for each of the indicators are needed.