• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1119-1127
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• 2012

The one of features of M2M communications, which are recently attracted attention as a future business of mobile communications, is that there is a large number of devices compared with traditional communication services. Hence, the control signal that are generated by the M2M devices may cause a significant congestion in the network and in order to solve this problem, a standardization is progressing for reducing the redundant signaling by managing M2M devices as a group in 3GPP standardization. In this paper, we propose a method of group based mobility management by managing M2M devices that have the same mobility as a group. In the proposed method, M2M devices that have the same mobility are grouped by the Mobility Management Entity (MME) and the MME elects a group header among the M2M devices in the group. Then, the group header performs the Tracking Area Update (TAU) on behalf of the group members to reduce the signaling overhead of mobility management. With the proposed method, we can achieve 80% decrease of the signaling overhead of mobility management compared with the case where each M2M device individually performs its TAU procedure.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.9
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• pp.1112-1124
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• 2011

The development of computer graphics and Internet technology has created a 3D Web-based virtual world that has transformed the global fashion industry environment. In this study, the application cases of 3D virtual fashion education were analyzed to discuss the necessity and application of a 3D apparel CAD curriculum as part of a special education for global fashion talent at Korean fashion-related colleges. Prior studies, literature, photo data and Internet data (in and out of Korea) were used for this study. The demonstration case studies were conducted for the virtual fashion education 'SLCC 2007' of Buffalo State College (U.S.), 'Ratava's Line (2004)' of SFU/FIT Collaborative Design Project (Canada and U.S.) and '2011 Graduation Fashion Show' of Ueda Fashion College (Japan). The results of the study show that the 3D apparel CAD system (as a core technology of the IT fashion industry) would allow the current mass production concept to change to a new paradigm of 'mass customization' along with new fashion business types that include global fashion companies and Web-based Internet, mobile and virtual-world shopping malls. In addition, it appears that the system should be included in the curriculum of fashion-related colleges and institutes to educate technical designers for the global fashion industry and global fashion talent with comprehensive system operation and management ability, and to promote single proprietor companies.

• The Korean Journal of Applied Statistics
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• v.26 no.1
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• pp.23-36
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• 2013

In this study, we investigate how churn customers (who play a central connector or broker role) affect other customers' churn in their call networks with ego-network analysis using call data of a mobile telecom company in Korea. As a result of investigating Reciprocal Network, we found a relationship of attrition among churn customers. Churn provokers who influence other customers' attrition exist in customer churn networks. The characteristics of churn provokers is that they play a central connector and broker role in their groups. The proportion of churn provokers increases and the churn provoker's influence increases because the network is a reciprocal one.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.87-96
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• 2007

Ubiquitous is a Latin-derived word meaning "to exist at any time and place" like water or air. In computing, the word "ubiquitous" indicates an environment in which users have access to networks without any limitation regarding computer networks or places. Important issues in building Ubiquitous Korea (U-Korea) are the social problems appearing with a rapid increase in the old age population. Nowadays, with the rise of the nuclear family, the increase in the number of elderly people living alone, and the change in the status of women, both wives and husbands are employed outside the home, and the relatives who would be responsible for supporting the elderly sometimes are on long or short business trips, and it happens that old people can't be looked after. Therefore the government developed a wireless paging system for the sick, disabled, old and weak so that when an emergency happens, by just simply dialing 119, an emergency aid center could take prompt action. However, the present wireless paging systems composing the under-layer of the emergency aid information system have some problems, such as, a lack of reliability, problems among terminals, mobile transmitters and receiving terminals, the users' refusal to admit the need for the system and poor operational skills, administrators' perfunctory management and checks, etc. On account of these problems, the system efficiency has degraded and therefore a system upgrade is necessary. In this paper, we attempt to evaluate the newly implemented SAFE119 system, a new wireless paging system seeking to correct the problems of the current system.

• Journal of radiological science and technology
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• v.27 no.4
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• pp.37-41
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• 2004

Purpose : Raise ability cultivation in presence at a sicked business by performance management estimation of device through measurement. Also Learn a technology that measure exact tube voltage, exposure time, output dose. And it is to grasp photofluorography X-ray generator existing circumstances using at hospital. Material & Method : Investigated Photofluorography X-ray generator(inside, outside each 10) of 10 university hospitals using tube voltage, exposure time, output dose measuring instrument. Result : Photofluorography device that tube voltage correctness is incongruent by examination PAE decision came out 3, and at exposure time correctness examination 2 incongruent, Also 3 that calculate coefficient of variation about exposure in repeatability examination of exposure were incongruent. Inappropriate photofluorography device is 5 outside hospital(mobile unit) and the thing in hospital was 3 in 3 kind of efficiency test. It appeared high that photofluorography device outside hospital is more incongruent than thing in hospital. Conclusion : May ready situation that can offer patient medical service of good quality by radiation exposure reduction, image quality administration, retake decrease etc. by keeping performance of Photofluorography device. Therefore, is considered that need on-time efficiency test.

• Journal of Broadcast Engineering
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• v.13 no.5
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• pp.719-731
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• 2008

This paper defines QoE (Quality of Experience) for multi-view video streaming service over WiBro and proposes the CLO (Cross-Layer Optimization) algorithm can maximize this. Proposal CLO algorithm contains from physical layer to video layer. Under the time-varying wireless channel condition, the CLO technique takes view-wise and the temporal priority of the multi-view video into consideration in order to decide the transmission of frames and its FEC level. At the handover situation, it is shown through computer simulation that the optimal quality of the multi-view video can be achieved using the minimum amount of resources if the proposed CLO technique is applied.

• Convergence Security Journal
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• v.16 no.4
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• pp.63-68
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• 2016

This study examined the current state of fitness IT which are commercially available, and proposed the prospect and promoting plans for fitness IT. Latest wearable smart market has been reorganized into smart watch market and fitness tracker market. Fitness trackers which are typical devices of fitness IT technology has developed various types of such as watch, band, clothes, glasses, and lens. Until now, the most popular type of fitness tracker are watch and band including clip, necklace, hair band etc.. Also Apple and Google referred to as the two major axes of mobile platform has provided a health-related platform such as "Healthkit" and "Google Fit" for preoccupying the fitness business. The view of the fitness IT has seen a continuous growth trend considering smaller and lighter of fitness-related wearable device. To continuous growth and promote of fitness IT, it is expected to require mash-up a variety of fitness applications and services, ensuring the convenience of user experience, design and resonable price.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.678-691
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• 2015

Internet and mobile traffic continues to surge exponentially in recent years due to popularization of smart devices, the appearance of various internet services carrying large amount of traffic from richer content and applications. This phenomenon leaded to various network problems such as the congestion delay, the non-balanced traffic ratio between ISPs, the continuous network investment cost and the Internet access problems. In light of changed data-driven communication ecosystem, There are growing concerns by both academia and industry that settlement-free peering and full transit regime have the limitations such as not only difficulties in maintaining mutual benefits but also difficulties in securing investment incentives for upgrading network performance and quality. Thus, it becomes more necessary for introducing the evolved internet interconnection regime which can fulfill the All-IP network environment. This study derives core issues regarding internet interconnection regime in Korea and suggest new evolved alternatives based on three point of view(traffic optimization, cost optimization, network investment optimization) through the empirical analysis.

• Journal of the Korea Society of Computer and Information
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• v.18 no.3
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• pp.11-18
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• 2013

In this paper, we propose a new design scheme of N-Screen emulator based on Cloud and then implement the emulator, in order to solve the critical point of N-Screen emulator based on Cloud. This method, without the emulator in the server, will be able to confirm the features of the emulator with a browser using Web Service. This means that the identical service is possible without regard to personal computer or mobile environment. Also, in order to emulating each different web browser engine of the various devices separately, we revise and manage the WebKit engine to be suitable to the characteristics of each device. In the previous design method, the number of emulators which can be shown in a monitor is restricted to 2 or 3. However, we show that the proposed design method can improve the performance of server to the extent that this method could operate more than 100 emulators per each server.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.131-139
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• 2016

Given social problems of service addiction such as mobile messenger services(MMSs), many studies on service management and information systems have examined the negative outcomes of service addiction. MMS addiction significantly influences user's health and academic performance. In this regard, this study investigated the effects of MMS addiction on user's health and academic performance problems. We posit personal traits and service features as key antecedents of MMS addiction. The research framework was tested by using survey data collected from 162 university students who have frequently used Kakaotalk. The analysis results found that MMS addiction significantly influences users' health and academic performance problems. The findings of this study indicate that self-esteem and self-control play an important role in generating MMS addiction. While attention significantly affects MMS addiction, social relationship formation and perceived enjoyment are not significantly associated with MMS addiction. The analysis results help MMS providers and government establish policies or guidelines to induce healthy MMS use.