• Journal of The Korea Institute of Healthcare Architecture
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• v.17 no.3
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• pp.43-51
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• 2011

The mobility and accessibility enhancement is gradually becoming a global interest due to the growth in the aging population and concerns about people with disabilities. The main purpose of this study is to know the current situation in barrier-free level in railroad facilities in order to allow the mobility handicapped to travel in a safe and convenient manner. The research has started with investigating current situation for the mobility handicapped people and explores the needs of barrier-free facilities. 84 domestic railroad facilities were evaluated based on assessment tool developed from the mobility handicapped act. As a result, the fact that the mobility handicapped experienced limited accessibility due to various types of obstacles in the facilities was discovered. Based on the evaluation, obstacles in the facilities were analyzed and categorized by specific dimensions, users' accessibility, mobility, usability, and clarity (way-finding). This study suggests barrier-free design for passenger facilities focused on train station. Because mobility and accessibility are emphasized in current society, improvement of the mobility handicapped' movement should be considered. Barrier-free design for passenger facilities should be realized throughout comprehending the reasons why these obstacles occur in the facilities not using installation convenience facilities. This study has meaning in finding out the obstacles in each cause of occurrence(accessibility, mobility, usability, and clarity (way-finding)).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1344-1367
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• 2014

Mobile traffic is increasing a masse because of the propagation of the Internet and the development of wireless mobile technology. Accordingly, the Network Local Mobility Management (NETLMM) working group [1] of the Internet Engineering Task Force (IETF) has standardized Proxy Mobile IPv6 (PMIPv6) [2] as a protocol for accomplishing the transmissibility of mobile terminals. PMIPv6 is a network-led IP-based mobility management protocol, which can control terminal mobility without depending on the type of access system or the capability of the terminal. By combining PMIPv6 and the mobility of Session Initiation Protocol (SIP), we can establish terminal mobility and session mobility through a more effective route. The mobility function can be improved and the overlap of function reduced as compared to that in the case of independent operation. PMIPv6 is appropriate for a non-real-time service using TCP, and SIP is appropriate for a real-time service using RTP/UDP. Thus, in the case of a terminal using both services, an effective mobility management is possible only by using PMIPv6 together with SIP. In order to manage mobility in this manner, researches on PMIPv6-SIP are in progress. In line with this trend, this paper suggests a new PMIPv6-SIP architecture where when a mobile terminal conducts a handover, a network-led handover while maintaining the session without the addition of a special function or middleware is possible along with effective performance evaluation through mathematical modeling by comparing the delay and the packet loss that occur during the handover to the Pure-SIP.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1078-1087
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• 2014

In the conventional centralized mobility management schemes, it can lead to single points of failure, occurrence of a bottleneck, since all data and control are concentrated on the mobility anchor which is located in home network. In the current research of distributed mobility management, it is doing research into distributed mobility management which is supported by distributed mobility anchors. Such schemes do not consider a failure of the mobility anchor. However, it could be an issue under tactical environment since it occur non-service problem due to anchor movement, maintenance, failure, etc. In this paper, we proposed new DMM scheme named T-DMM(Tactical-Distributed Mobility Management) which can support handover even if mobility anchor breaks down. From the numerical analysis, we evaluate signaling cost and handover latency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.911-916
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• 2001

Structural acoustic modification method based on the structural mobility analysis is applied to reduce the structure-borne noise radiated from hard disk drive system. Sound intensity techniques and ODS(Operational Deflection Shape) techniques are also used in order to provide the structural acoustic information for the mobility modification. The sound intensity is for the acoustic visualization of the noise source locations, and the ODS is for the visualization of the vibration pattern and its dynamic characteristics of the noise sources. Using visualization information of sound and vibration, local structural input mobility is reduced in the frequency band of interest by designing asymmetrical wave-stringer structure in the wave-number domain as well as frequency domain. The overall sound pressure level is reduced by 4dB and its controlled sound power radiated from the disk drive is proved to under 2.8Bel in idle-spinning mode and 3.1 Bel in random-seeking mode, which are the lowest noise levels in the hard disk drive industry.

• Journal of Labour Economics
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• v.29 no.2
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• pp.145-169
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• 2006

This study analyze the effect on wage, labor mobility by using Craft II Class certification out of National skill certification. In this article, we used the parametric and nonparametric method. In the former we used IV that the fraction of certification by occupation by firm scale to solve the selection problem. In the latter, it's used matching method and kernel regression. The paper shows that certification effect on wage has about 5.1~9.9%. The result of analysis between certification and labor mobility indicates better certification effects on long term tenure to the same firm than certification effects on wage from labor mobility. Also, we knew that the employee which have no certification relative is difficult to be established in the same workplace.

• Journal of Labour Economics
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• v.33 no.2
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• pp.53-89
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• 2010

Curricula relevant to labor market needs are often designed with the goals of individual employment and regional development at the forefront. This study provided information on regional scope by investigating the extent and determinants of the geographic mobility of vocational high school graduates and the effects of that mobility on first-job wage rates. Geographic mobility was defined as being employed in other provinces in which vocational schools were located. About 38% of graduates were employed in other provinces. Geographic mobility was positively related to gender and human capital such as health, course of study, vocational certificate, and job training. Mobility led to higher wage rates even after controlling for sample selection bias. The implication is that vocational high school curricula which focus excessively on provincial concerns may weaken a workforce's effectiveness.

• International Journal of Advanced Culture Technology
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• v.2 no.1
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• pp.1-13
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• 2014

In next-generation wireless networks, provisioning of IP-based network architecture and seamless transmission services are very important issues for mobile nodes. For this reason, a mobility management mechanism to support global roaming is highly regarded. These technologies bring a broader life by using a global roaming account through the connection of multiple devices or technology to mobile users; they also provide real-time multimedia services. This paper presents a comprehensive performance analysis of fast handover for hierarchical mobile IPv6 (F-HMIPv6), hierarchical mobile IPv6 (HMIPv6), Proxy Mobile IPv6 (PMIPv6), and fast Proxy Mobile IPv6 (FPMIPv6) using the fluid-flow model and random-walk model. As a result, the location update cost of the PMIPv6 and FPMIPv6 is better than that of HMIPv6 and F-HMIPv6. These results suggest that the network-based mobility management technology is superior to the hierarchical mobility management technology in the mobility environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.397-408
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• 2017

As mobile traffic increases rapidly, DMM (Distributed Mobility Management) has been proposed as a mobility management technology for seamless communication of mobile devices as mobile traffic increases rapidly. the DMM distributes mobility management from the core network to the edge network, enabling stable binding updates with low latency. However, the DMM still have network delay and security problems for sessions. In this paper, we point out the problems existing in the DMM and propose a new protocol in which the MN (Mobile Node) directly participates in authentication and mutual authentication is correctly performed to solve this problem. We demonstrate not only security improvements but also performance improvements with performance analysis.

• Journal of Astronomy and Space Sciences
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• v.29 no.4
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• pp.413-422
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• 2012

In recent years, a number of missions have been planned and conducted worldwide on the planets such as Mars, which involves the unmanned robotic exploration with the use of rover. The rover is an important system for unmanned planetary exploration, performing the locomotion and sample collection and analysis at the exploration target of the planetary surface designated by the operator. This study investigates the development of mobility system for the rover ground model necessary to the planetary surface exploration for the benefit of future planetary exploration mission in Korea. First, the requirements for the rover mobility system are summarized and a new mechanism is proposed for a stable performance on rough terrain which consists of the passive suspension system with 8 wheeled double 4-bar linkage (DFBL), followed by the performance evaluation for the mechanism of the mobility system based on the shape design and simulation. The proposed mobility system DFBL was compared with the Rocker-Bogie suspension system of US space agency National Aeronautics and Space Administration and 8 wheeled mobility system CRAB8 developed in Switzerland, using the simulation to demonstrate the superiority with respect to the stability of locomotion. On the basis of the simulation results, a general system configuration was proposed and designed for the rover manufacture.

• Korean Management Science Review
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• v.23 no.1
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• pp.21-41
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• 2006

Given the growing deployment of mobile offices, we need to understand the fectors which affect their successful use and implementation. We in this paper present a parsimonious model which integrates the IS success model and the TAM. The main feature of the model is that it allows one to explore the role of mobility of mobile office systems in determining the level of system usage and dependence. Although the mobility is the key property of any mobile system, there is little research effort exerted to understand how mobility affects the traditional IS factors such as perceived ease of use and usefulness. In addition to the system usage, this model also uses dependence as the dependent variable. This is expected to provide richer understanding of the study context. We collected survey data from 1,614 field service workers of a major domestic electronic company. They use PDAs to retrieve information regarding the specifics of the customer service requests and to report what has been done for each service job. The results from SEM analysis show that mobility improves the perceived ease of use which then leads the field service workers to depend more on the PDA systems. Interestingly enough, however, the workers' satisfaction does not cause more frequent use of the system.