• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.1994-2017
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• 2022

In view of the past, the mobility of the multicast source in the mobility networks is seldom discussed in the traditional multicast protocols. It is a heavy cost for the traditional multicast protocols to reconstruct the multicast tree in the Network Mobility (NEMO) environment. This article proposes an alternative multicast protocol, referred to as Mobility-Sensitive Multicast protocol (MSM), for the NEMO environment. The MSM can be considered as an alternative version of the Multicast Listener Discovery (MLD) protocol to maintain the multicast tree in the NEMO. There are two obvious contributions for the MSM. Reconstruct mechanism could rebuild the multicast tree for the mobility of the multicast source. Multi-group suppression mechanism reduce the multicast tree maintaining cost for the mobility of the multicast members. Through the performance evaluations and analyses, the MSM has less cost to maintain the multicast tree than the traditional multicast protocols, especially for a large numbers of multicast groups. Moreover, the MSM allows the mobility of the multicast source to reconstruct the multicast tree easily.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3656-3671
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• 2016

Most of the research in the area of wireless communications exclusively relies on simulations. Further, it is essential that the mobility management strategies and routing protocols should be validated under realistic conditions. Most appropriate mobility models play a pivotal role to determine, whether there is any subtle error or flaw in a proposed model. Simulators are the standard tool to evaluate the performance of mobility models however sometimes they suffer from numerous documented problems. To accomplish the widely acknowledged lack of formalization in this domain, a Coloured Petri nets (CPNs) based random direction mobility model for specification, analysis and validation is presented in this paper for wireless communications. The proposed model does not suffer from any border effect or speed decay issues. It is important to mention that capturing the mobility patterns through CPN is challenging task in this type of the research. Further, an appropriate formalism of CPNs supported to analyze the future system dynamic status. Finally the formal model is evaluated with the state space analysis to show how predefined behavioral properties can be applied. In addition, proposed model is evaluated based on generated simulations to track origins of errors during debugging.

• International journal of advanced smart convergence
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• 제7권4호
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• pp.197-205
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• 2018

Nowadays, wireless sensor networks (WSNs) have been widely adopted in structural health monitoring (SHM) systems for social overhead capital (SOC) public infrastructures. Structural health information, environmental disturbances and sudden changes of weather conditions, damage detections, and external load quantizing are among the capabilities required of SHM systems. These information requires an efficient transmission with which an efficient mobility management support for wireless networks can provide. This paper deals with the analysis of mobility management schemes in order to address the real-time requirement of data traffic delivery for critical SHM information. The host-based and network-based mobility management protocols have been identified and the advantages of network mobility (NEMO) enabled Proxy Mobile Internet Protocol version 6 (PMIPv6) have been leveraged in order to address the SHM information transmission needs. The scheme allows an efficient information transmission as it improves the handover performance due to shortened handover latency as well as reduced signaling overhead.

• 한국통신학회논문지
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• 제28권6B호
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• pp.563-572
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• 2003

차세대 이동 통신망 환경에 Mobile IP 방식을 적용하였을 경우 빈번히 발생하는 핸드오프로 인한 재등록 과정의 오버헤드 증가와 등록 시의 지연으로 인한 패킷 손실 증가 등의 마이크로 이동성(micro-mobility) 문제가 발생할 수 있다. 본 논문에서는 이 문제의 해결을 위해 IP 기반 무선 액세스 망에서 마이크로 이동성을 효율적으로 지원하는 ANMM(Access Network Mobility Management) 방식을 제안한다. ANMM 방식은 액세스 망 내에서 노드가 이동할 때 발생하는 핸드오프 등록 과정을 액세스 망 자체적으로 처리하여 등록 지연과 시그널링 오버헤드를 감소시킨다. 또한 핸드오프 시의 무선 구간에서의 시그널링을 최소화하여 무선 자원의 낭비를 줄일 수 있다.

• Journal of Contemporary Eastern Asia
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• 제14권1호
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• pp.5-22
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• 2015

This study examines how different uses of social network sites (SNS) and mobile phones (MP) to communicate with friends and business associates are related to the acquisition of job-related information, job mobility, and entrepreneurial intentions, using social capital as its main theoretical lens. To this end, a nationally representative, random digit dialing (RDD) survey was conducted in Singapore. Path analyses show that SNS interactions with friends are positively related to both bonding and bridging social capital. The former is linked with greater job mobility, the latter with entrepreneurship, and both are associated with more job-related information. SNS interactions with business contacts are directly positively related to job-related information and entrepreneurship. For mobile phones, interactions with friends are positively related to social capital, job information and entrepreneurship. Professional networking is associated with more bridging social capital, job information and job mobility. Bonding capital is found to be linked with greater job mobility, while bridging capital has a positive relationship with both entrepreneurship and job mobility.

• Journal of Computing Science and Engineering
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• 제5권1호
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• pp.71-84
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• 2011

Pervasive applications such as digital memories or patient monitors collect a vast amount of data. One key challenge in these systems is how to extract interesting or unusual information. Because users cannot anticipate their future interests in the data when the data is stored, it is hard to provide appropriate indexes. As location-tracking technologies, such as global positioning system, have become ubiquitous, digital cameras or other pervasive systems record location information along with the data. In this paper, we present an automatic approach to identify unusual data using location information. Given the location information, our system identifies unusual days, that is, days with unusual mobility patterns. We evaluated our detection system using a real wireless trace, collected at wireless access points, and demonstrated its capabilities. Using our system, we were able to identify days when mobility patterns changed and differentiate days when a user followed a regular pattern from the rest. We also discovered general mobility characteristics. For example, most users had one or more repeating mobility patterns, and repeating mobility patterns did not depend on certain days of the week, except that weekends were different from weekdays.

• 한국통신학회논문지
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• 제36권1A호
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• pp.82-89
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• 2011

IETE Proxy Mobile IPv6는 이동 단말의 이동성을 지원하기 위한 망 기반 이동성 관리 기술이다. PMIPv6는 Mobile Access Gateway 와 Local Mobility Anchor 사이의 터널을 형성하고 항상 패킷이 Local Mobility Anchor를 통하여 전달되도록 설계하여, Local Mobility Anchor 병목현상 및 종단간 지연이 증가하는 문제점이 있다. 이러한 문제점을 해결하기 위해 경로 최적화 수행 기능 감지, 경로 최적화 절차 등의 많은 연구가 진행되고 있으나 추가적인 시그널링으로 인한 오버헤드가 증가하고 다중 Local Mobility Anchor 환경에 적용하기에 어려움이 있다. 따라서 본 논문에서는 다중 Local Mobility Anchor 환경을 고려한 PMIPv6 기반의 향상된 경로 최적화 방안을 제안하였다. PMIPv6 도메인 내 모든 Local Mobility Anchor의 정보를 Mobile Access Gateway가 유지하도록 하여 신속하게 경로 최적화를 수행하도록 하였으며, Local Mobility Anchor에 경로 최적화 상태 정보를 저장하여 핸드오버 이후에도 신속한 경로 최적화를 지원하도록 하였다. 또한 핸드오버 시에 상대 노드의 Mobile Access Gateway에 버퍼링 기능을 추가하여 경로 최적화를 수행하는 동안의 패킷 순서화 문제를 해결하였다. 제안된 방안의 성능은 OPNET 시뮬레이터를 이용하여 분석하였으며, 이를 통해 제안 방안의 우수성을 검증하였다.

• Journal of information and communication convergence engineering
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• 제6권3호
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• pp.245-248
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• 2008

Everytime a node moves out of its area, the connection to the node encounters a handover which may cause much latency. NetLMM(Network based Localized Mobility Management) supports the mobility management for such nodes and improves handover latency using MIH(Media Independent Handover) function. In this paper, we add some messages to NetLMM procedure to improve handover latency and analyze its effects through a scenario based approach

• Asia pacific journal of information systems
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• 제24권2호
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• pp.115-140
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• 2014

In a dynamic business environment, the enterprise mobility solution for a mobile office (EMS) has been adopted to increase the competitive edge of organizations. By using an EMS, performance is expected to be enhanced. However, the related literature has paid little interest to the impact of system quality in an EMS on the information quality produced by the system. On the basis of socio-technical theory, we posited that the system quality in an EMS influences information quality. In addition, we investigated the relationships between the above two qualities, use and job performance by considering task mobility and task inter-dependence as control variables. Survey respondents were from many industries using EMSs. The result of structural equation modeling shows that system quality positively affects information quality, and other relationships in the model are proven statistically significant. We also found that system quality has stronger impacts on use and job performance than information quality does in EMS. However, system quality does not affect use in case both task mobility and task inter-dependence exist. The theoretical and practical implications of the result are discussed in the paper.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.71-87
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• 2015

Mobile users want to be provided with undisrupted network services when they navigate on the Next-Generation (NG) wireless networks. For that, interlocking with a heterogeneous network is important, but there have been few studies on the method for guaranteeing global mobility. Thus, this paper proposes the Proxy-LMA technique, the mobile IP-based global inter-networking system, to enhance global mobility and interoperability within the Next-Generation (NG) network environment. The purpose of the proposed Proxy-LMA system is to expand the boundary of the mobility with regards to the existing mobility management protocol (PMIPv6 and MIPv6) in order to guarantee global mobility and interoperability within the heterogeneous network environment. The results of the performance evaluation showed that the proposed Proxy-LMA system was more efficient than other methods from the standpoint of signaling cost and delay in the heterogeneous network environment.