• Geophysics and Geophysical Exploration
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• v.15 no.3
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• pp.121-128
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• 2012

Absorbing boundary conditions are used to mitigate undesired reflections that can arise at the model's truncation boundaries. We apply a complex frequency shifted perfectly matched layer (CFS-PML) to elastic wave modeling in the frequency domain. Modeling results show that the performance of our implementation is superior to other absorbing boundaries. We consider the coefficients of CFS-PML to be optimal when the kinetic energy becomes to the minimum, and propose the modified CFS-PML that has the CFS-PML coefficient ${\alpha}_{max}$ defined as a function of frequency. Results with CFS-PML and modified CFS-PML are significantly improved compared with those of the classical PML technique suffering from large spurious reflections at grazing incidence.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.15-20
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• 2020

A manufacturing industry has secured its competitiveness through cost reduction, research for new products, development of manufacturing technology traditionally. However, many manufacturers are being required of innovative efforts for business sustainability by emergence of new technology and industry owing to fast technology development and convergence among technologies and industries. Continuous growth can not be expected with the way of simple manufacturing and sales under the 4^th industrial revolution era. Separation of service from product is getting more vague in some specific area and a service provider is often offering its own product together. Innovation destroying manufacturing value chain with servitization can only create the new value. Basic concept of servitization, paradigm change and future prospect of manufacturing industries suffering from the 4^th industrial revolution will be analyzed in this paper. Also, the strategy, application and methodology for servitization required in the convergence period will be researched.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.367-373
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• 2017

The study aims to suggests mobile application service that helps to reduce physical and mental suffering after surgery for breast cancer patients constantly increasing. At first, I analyze literature research to understand the breast cancer and similar services for achieving study purposes. After I finally design a mobile application that offers to customed one-to-one specialist coaching service focused on post-treatment management by using a double diamond design process model. In detail, first, I analyze the current program and comprehend user needs through interviews with the person such as breast patient, protector, nurse, salesperson in cancer center. Second, I specify the entire scenario, concept and keyword based on the persona and the customer journey map representing user. Third, I propose the mobile application for the ultimate goal by producing prototype to effectively communicate with specific functional descriptions. I hope this service will improve the quality of their lives.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.950-958
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• 2017

Viaduct increases the height of subway catenary, namely magnifies lightning attraction scope that lead to higher possibility of suffering lightning stroke. Therefore, it is necessary to analyze performance of lightning striking to catenary of subway in viaduct section and propose an improving lightning protection scheme. In this paper, using ATP-EMTP simulation software to establish an associated model to evaluate lightning withstand level of catenary with existing lightning protection schemes including arrester and grounding point, an improving lightning protection scheme is proposed - every pillar ground earth and arresters are installed with some installing spacing between 200m to 400m based on lightning damage degree and reliability requirements - according to analyzing results: while lightning withstand level is lowest for lightning striking to the neutral pillar, lightning withstand level is greatest for lightning striking to the both-ends pillar that arrester and grounding point are both installed; grounding point could obviously improve lightning withstand level for lightning striking to ground wire while arrester could obviously improve the lightning withstand level for lightning striking to catenary; every pillar ground earth could enhance the lowest lightning withstanding level up to 2.5 times than of that pillar ground earth across every 200m.

• The Journal of Bigdata
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• v.1 no.1
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• pp.61-66
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• 2016

With big data analysis, companies use the customized marketing strategy based on customer's information. However, because of the concerns about privacy issue and identity theft, people start erasing their personal information or changing the privacy settings on social network site. Facebook, the most used social networking site, has the feature called 'Likes' which can be used as a tool to predict user's demographic profiles, such as sex and age range. To make accurate analysis model for the study, 'Likes' data has been processed by using Gaussian RBF and nFactors for dimensionality reduction. With random Forest and 5-fold cross-validation, the result shows that sex has 75% and age has 97.85% accuracy rate. From this study, we expect to provide an useful guideline for companies and marketers who are suffering to collect customers' data.

• Journal of Intelligence and Information Systems
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• v.7 no.1
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• pp.177-197
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• 2001

This paper is aimed at proposing a data mining-driven analysis to manage the customer defection rate in the bank. After 1997 IMF crisis, Korean banks were suffering from hard-pressed restructuring. At the heart of such restructuring effects, there was the need to manage the customer more effectively than ever. So far, many banks in Korea used to a poor management of customers without any highly-skillful techniques. In line with this argument, we propose several data mining techniques to determine more effective technique far managing customer deflection. We applied three data mining techniques such as logit model, neural network, and C5.0. Experiment data were collected from personal deposit account data of a specific bank in Korea. After experiments, we found that C5.0 showed more robust performance compared to other two techniques. On the basis of those experiment results, we proposed customer defection management policy.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.235-246
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• 2002

While the Internet is suffering from the massive data such as video stream, IP multicast can ease the load of the Internet by enabling one copy of digital information to be received by multiple computers simultaneously. But If multicast is based on UDP, packets are delivered using a best-effort Policy without any reliability, congestion control or flow control. Multicast group members can join or leave a multicast group at will, and multicast uses broadcast mechanism, it's very hard to keep security from unauthorized members. In this paper, we introduce a new reliable multicast protocol TRDMF proper for one-to-many multicast model with reliability, flow control, congestion control and key management.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.4
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• pp.345-354
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• 2007

A sedimentation analysis has been attempted to figure out sedimentation environment due to construction of coastal jetties, such as fish harbor dike, flow guided dike and jetty in shallow Kusipo area, in which tidal range marks up to 6.6 meters in spring tide. As an initial approach of understanding field measurement were done on several stations along reference lines with total station and photo analysis taken by remote controlled small air craft far one and half years. Also numerical tests were done by 2-D ADCIRC model considering dry-wet treatment to evaluate flow and bottom shear stress variations. According to direct measurement, deposition seems to be dominant on Kusipo beach. Model results show bottom shear stress lessens to $0.10{\sim}0.15\;N/m^2$ on most shadow zone of jetties and the inner zone is suffering sedimentation as a result of dike construction. However this is the first approach with limited analysis, thus it should be dealt further considering physical characteristics of bottom sediments in a complete sediment model on upcoming study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.447-454
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• 2009

This study investigates to information medium and small enterprises and analyzed how enterprise's integration information system affects to business users. Many medium and small enterprises are introducing and operate new integrated system for latest several years, but it is suffering difficulty in substantial business analysis as unstable system, maintenance and insufficiency of management controls. Therefore, in this study, tried to analyze common problem and solution to enterprise which is operating integration information system stably. Designed study model and research hypothesis to variable of information level, system availability, information availability, information creation level, service availabilities for this analysis. This studγ got conclusion as following. First, If system usefulness, information usefulness, information creation level, service usefulness are high, Analysis result about user business performance appeared very positive effect. Second, Analyzed to which lack a little user realization about information level in details measured variable. This study will be able to become data that is useful in stable system introduction in various field of industry of medium and small enterprises hereafter.

• Korea Journal of Hospital Management
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• v.13 no.4
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• pp.27-45
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• 2008

This research focused on a total of 378 patients with external injuries under the age of 14 who visited the emergency center at a university hospital in Korea, during the months of January, April, August and November between January and December of 2007. In addition, the survey was conducted only on even number days and ranged across the whole year to reflect the impact of seasonal characteristics on the collected data. The research focused on determining the characteristics and inflicting cause of these patients with external injuries, analyzed the total time spent in the emergency room and obtained the following results. 1. When classifying the patients into different genders, the proportion of males (67.5%) was higher than that of females (32.5%). According to the different age groups, the highest ratio, at 61.1 %, was patients under the age of six. 2. Looking at the total number of minutes spent in the emergency room, the longest amount of time occurred during April with 162.7 minutes, followed by 121.9 minutes in January and 92.4 minutes in November. August had the shortest period of time spent in the emergency room, a significant statistical difference from the other periods of the year (p<0.001). 3. Regarding the amount of time required for each examination, patients required to provide a urine test spent an average of 204.7 minutes while those who did not spent 113.5 minutes on average. This is a 5% statistical difference among the two groups (p>0.05). 4. Looking at the five most commonly diagnosed problems in the emergency room, the total number of people with these top five commonly diagnosed illnesses comprised 55.6%, or 210 patients out of 378. 5. Utilizing the Decision Tree Model to estimate the total number of minutes required per visit, the first classifications were made using a chemical examination factor. People subject to chemical classification spent an average of 177.7 minutes, which was longer than the overall average of 115.2 minutes, and those exempt from chemical examination spent an average of 103.8 minutes, which was shorter than the average Conclusion; Effort to curtail the total time spent in emergency rooms is vital in guaranteeing efficient management of hospitals and providing medical services. The delay experienced by many comprehensive professional medical centers must be resolved through the establishment of effective delivery of medical services, increased supply of patient rooms and other policy oriented implementations. However, for now, this problem must be resolved by increasing the level of patient satisfaction and guaranteeing effective operation of patient rooms, which will significantly contribute to the general management and success of hospitals and institutions.