• Journal of Korea Multimedia Society
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• v.22 no.12
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• pp.1438-1446
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• 2019

Recently, the number of mobile users as well as high-speed Internet user has been increasing rapidly. Moreover, traffic is growing fast as services that provide real-time content such as Youtube and Netflix become popular. The problem of traffic control in real-time content services is important because many people use cell phones to receive real-time content. In this regard, the field of CCN is currently being studied. We studied the mobility of nodes among CCN research fields. Node mobility can be divided into three categories : consumer mobility, intermediate node, and provide mobility. In this paper, we propose Mobility Node Support(MD-INS) to support the intermediate-node mobility in CCN real-time services. Experimental results show that the proposed scheme shows better performance than CCN in terms of service disconnection time and packet loss.

• Journal of Korea Multimedia Society
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• v.20 no.9
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• pp.1527-1540
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• 2017

Recently, due to the rapid development of the internet, the production and demand of high capacity contents are rapidly increasing. In order to accommodate the changing trend of internet usage, researches on CCN, the future internet architecture, are actively being conducted. Mobility support is an important challenge in CCN real-time services, given that today's internet environment is changing to mobile and real-time services are increasing. In CCN real-time services, the mobility problem can be largely divided into consumer mobility, provider mobility, and intermediate-node mobility. Among them, when the intermediate-node moves in the CCN real-time services, the service disconnection occurs and the QoS degradation is caused. In this paper. we propose Intermediate-Node Mobility Support(INMS) to support the intermediate-node mobility in CCN real-time services. Experimental results show that the proposed scheme shows better performance than CCN in terms of service disconnection time and packet loss.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.509-512
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• 2003

본 논문은 무선랜 환경에서 Mobile IPv6 Node가 이동 시에 발생하는 Handover Latency 를 줄이기 위한 새로운 알고리즘을 제안한다. 현재 Mobile IPv6 Fast Handover Protocol 은 Layer2 에서의 Handover 의 도움을 전제로 하기 때문에 실제 구현상에서 Real-time 이나Delay 에 민감한 Application 에 적용하기 어렵다. 이 문제를 해결하기 위해 무선랜에서 사용하는 Beacon 신호를 이용한 Dominant NAR 알고리즘을 적용하여 MIPv6 Fast Handover 과정을 선 처리하여 Handover Latency를 줄이고자 한다.

• Journal of the Korea Society for Simulation
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• v.11 no.1
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• pp.1-10
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• 2002

IETF proposed Fast Handover mechanism tn reduce the latency during which the mobile node is effectively dusconnected from the Internet. In this paper, we propose three buffering strategies and a bicasting strategy to resolve packet loss and packet disordering problems in Fast Hangover mechanism. Through Java-based simulation we show thats, packet loss and disordering problems have been resolved by our proposal. As the result the buffering and bicasting strategies can reduce the handover delay caused by packet loss and packet disordering, in addition.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.1
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• pp.99-105
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• 2012

Given the numbers of smartphones, tablets and other mobile devices shipped every day, more and more users are relying on the cloud as the main driver for satisfying their computing needs, whether it is data storage, applications or infrastructure. Mobile cloud computing is simply cloud computing in which at least some of the devices involved are mobile. Each node is owned by a different user and is likely to be mobile. Using mobile hardware for cloud computing has advantages over using traditional hardware. These advantage include computational access to multimedia and sensor data without the need for large network transfer, more efficient access to data stored on other mobile devices and distributed ownership and maintenance of hardware. It is important to predict job execution time in mobile cloud computing because there are many mobile nodes with different capabilities. This paper analyzes the job execution time for mobile cloud computing in terms of network environment and heterogeneous mobile nodes using a mathematical model.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.224-232
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• 2002

The routing protocols designed for wired networks can hardly be used for mobile ad-hoc networks due to limited bandwidth of wireless transmission and unpredictable topological change. Recently, several routing protocols for mobile ad-hoc networks have been proposed. However, when these protocols are applied to support real time services like multimedia transmission, they still have problems in ad-hoe networks, where the topology changes drastically. In this paper, we propose a new route selection algorithm which selects the most reliable rouse that is impervious to route failures by topological changes by mobile hosts. For reliable route selection, the concept of virtual zone (stable lone and caution zone) is proposed. The lone is located in a mobile node's transmission range and determined by mobile node's mobility information received by Global Positioning System (GPS). The proposed algorithm is applied to the route discovery procedure of the existing on-demand routing protocol, AODV, and evaluated by simulation in various traffic conditions and mobility patterns.

• Journal of Internet Computing and Services
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• v.14 no.3
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• pp.67-79
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• 2013

In wireless networks, efficient mobility management to support of mobile users is very important. Several mobility management schemeshave been proposed with the aim of reducing the signaling traffic of MN(Mobile Node). Among them, PMIPv6 (Proxy Mobile IPv6) is similar with host-based mobility management protocols but MN does not require any process for mobility. By introducing new mobile agent like MAG (Mobile Access Gateway) and LMA (Local Mobility Anchor), it provides IP mobility to MN. In this paper, we propose the analytical model to evaluate the mean signalingdelay and the mean bandwidth according to the type of MN mobility. As a result of mathematical analysis, MF-PMIP (Multicasting-based FastPMIP) outperforms compared to F-PMIP and PMIP in terms of parameters for the performance evaluation.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.411-413
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• 2000

Internet망에서 mobile comupting에 대한 관심은 커져하고 있다. Mobile IP는 노드의 이동성을 지원하는 방법 중의 하나이다. 그렇지만 handoff 하는 과정에서 발생하는 패킷 손실 때문에 신뢰성의 문제가 발생한다. 게다가 mobile node(MN)와 foreign agent(FA)사이가 무선 링크인 경우 패킷 손실은 더욱 심각하다. TCP/IP는 고정된 네트워크에서 고안되어진 것이기 때문에 기존의 TCP/Mobile IP가 무선에는 부적합하다. 그러므로 본 논문에서 TCP/Mobile IP와 application사이에 midddleware로써 mobile agen(MA)를 사용하는 것을 제안했다. TCP mobile agent(TCP MA)을 여러 application에서 TCP 성능의 향상을 위해 제안했다. TCP MA는 FA와 MN를 위해 행동하고, 그리고 MN의 현재 위치에 상관없이 MN에 결과를 보낸다. 이러한 TCP MA는 handoff 동안에 발생하는 패킷 손실을 감소시킨다.

• KIISE Transactions on Computing Practices
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• v.24 no.2
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• pp.77-81
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• 2018

Many studies that improve the efficiency of data collection and a network's lifetime by using a mobile sink have been conducted using wireless sensor networks. If a drone is used as a mobile sink, the drone can collect data more efficiently than can existing mobile sinks operating on the ground because the drone can minimize the effects of obstacles and the terrain. In this paper, we propose a rendezvous node selection scheme which considers estimated drone's trajectory and data collection latency of sensor networks for reliable data collection, when a drone whose trajectory is not predetermined works with terrestrial wireless sensor networks. A selected rendezvous node on the ground collects data from the entire network and it sends then collected data to the drone via direct communication. We also verify that the proposed scheme is more reliable than previous schemes without considering the drone's trajectory and data collection latency.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.508-516
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• 2016

When GPS signals are not available, a relative localization can be alternatively used to represent the topological relationship between mobile nodes. A relative location map of a network can be constructed by using the distance information between all the pairs of nodes in the network. If a network is large, a number of small local maps are individually constructed and are merged to obtain the whole map. However, this approach may result in a high computation and communication overhead. In this paper, we propose a reference-node selection scheme for relative localization map construction, which chooses a subset of nodes as a reference node that is supposed to construct local maps. The scheme is a greedy algorithm that iteratively chooses nodes with high degree as a reference node until the chosen local maps are successfully merged with a sufficient number of common nodes between nearby local maps. The simulation results indicate that the proposed scheme achieves higher localization accuracy with a reduced computational overhead.