• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.129-132
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• 2001

The ad hoc network was composed of Mobile hosts. Due to the limited transmission range of each mobile node hosts, in such an environment, it is essential for other hosts to coorperate to transfer packet to destination. Moreover, the existing routing protocol algorithms are not efficient on the ad hoc network because a mobile host operates router without fixed router. In this paper, we will compare and analysis for the performance of existing ad hoc network routing protocols through simulation.

• The Transactions of the Korea Information Processing Society
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• v.7 no.9
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• pp.2969-2979
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• 2000

A mobile host has failure causes such as failure of the mobile host, disconnection of the mobile host, and wireless link failure that have not been seen in traditional computing environments. So far there have been few studies on fault tolerance of a mobile host in mobile computing environments. The Lazy scheme, a failure recovery technique of the mobile host, is a cost-effective one. However, this scheme has a defect that the mobile host cannot be recovered from failure of the base station with acheckpoint of the mobile host. In this paper, we propose and evaluate the Redundant Lazy scheme for performance improvement of the Lazy scheme.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.993-996
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• 1999

A mobile agent is a program which is capable of migrating autonomously from host to host in the heterogeneous network, to perform some computation on behalf of the user. Mobile agents have many advantages in the distributed computing environment. But they are likely to suffer many attacks on the security due to the mobility. In order to make use of a mobile agent in the real applications, the security issues must be addressed. We deal with the problem which is concerned with protecting a mobile agent in transit and detecting a mobile agent clone. In this paper we propose a trust center based secure mobile agent transfer protocol. This protocol transfers a mobile agent securely from host to host and detects a mobile agent clone. We further show the security of the protocol against many attacks.

• Journal of Information Technology Services
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• v.7 no.2
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• pp.181-195
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• 2008

The rapid growth of mobile communication technology has provided the expansion of mobile internet services, particularly mobile realtime transaction takes much weight among mobile fields. There is an increasing demand for various mobile applications to process transactions in a mobile computing fields. Thus, During transmission in wireless networks a base station failure inevitably causes data loss of the base station buffer. It is required to compensate the loss for communication. The existing methods for a base station failure are not adequate because they all suffer from too much overhead and resolve only the link failure. In this paper, we study an efficient recovry systems for a mobile DBMS. We propose SLL (Segment Log List) that enables the mobile host to compensate data loss efficiently in the case of base station failure. In SLL, a base station deliveries an output information of data cells to a mobile host. when a base station fails, the mobile host can retransmit just next data cells. We also prove the efficiency of new method.

• Journal of the military operations research society of Korea
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• v.22 no.2
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• pp.73-89
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• 1996

This paper suggests the new IP, SIMIP(Simple Mobile IP), which supports a continuous mobility between a static host and a mobile host in the static TCP/IP LAN environment where mobile hosts are overlayed with cells. For designing a mobile protocol, routing optimization is very important, and it is directly related to the management mechanism of a mobile host's location information. When the mobile hosts' location information are centralized, the network has high risk when a centralized device fails. On the other hand, when they are distributed, the above problems are solved. But it requires complicated techniques in order to search the encapsulated addresses. SIMP centralizes mobile hosts' location information, minimizes the risk by automatically substituting the failed default mobile router with one of the multiple general mobile routers, and supports the optimal routing path through "default mobile router path alternation" Then since SIMIP isn't reasonable the operations informations to the chief in military operations room.ions room.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.1
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• pp.56-63
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• 2009

Contrast operating system installed on traditional PC, operating system installed to mobile IP host is a status not to be established a definite monopoly system. Accordingly, for the time being, it is expected that operating system operated in mobile IP host will be used various operating systems. Regardless of operating system, this condition is a very vulnerable to modified virus. Because operating system used in an individual host is very diverse, It makes technical development to cure complicated in detection efficiently these virus. In this thesis, By using VMware under the various operating system, I designed and implemented system which is able to test a modified virus. Also I implemented prototype system to operate under the real mobile condition.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.89-94
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• 2006

In the Mobile IP, the movement of Mobile Host(MH) causes packets to be transmitted through a long route. A Correspond Node(CN) first communicate with a Home Agent(HA) when a Mobile Host moved from one subnet to another subnet. The HH-MIP algorithm reduces an inefficient transmission of packets by regarding a Foreign Agent(FA) near a mobile host as a Temporary Home Agent(THA). However, The algorithm costs the unnecessary signaling by measuring the distance of route between a FA and a THA for handover in the case that a Mobile host comes from a THA which a current FA never communicated. To solve this problem, we propose a scheme called Hierarchical Home Agent Handover in Mobile IP(HHH-MIP) algorithm. Our HHH-MIP algorithm only searches tables in a router by using the hierarchical structure between a FA and a THA. The simulation results show that the HHH-MIP algorithm reduces the additional signaling cost.

• Journal of the Korea Society of Computer and Information
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• v.4 no.3
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• pp.78-92
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• 1999

In mobile computing environments, to efficiently use the narrow bandwidth of wireless networks a mobile host caches the data that are frequently accessed. To guarantee the correctness of the mobile transaction, the data cached in a mobile host must be consistent with the data in a server. This paper proposes a new strategy which maintains cache consistency efficiently when the data cached in a mobile host are inconsistent with the data in a server by the mobility of the mobile host at the asynchronous mobile environment. In this strategy, the size of the invalidation message is relatively small and is independent of the number of data to be invalidated under conditions of variable update rates/patterns. So this strategy uses the narrow bandwidth of wireless networks efficiently and reduces the communication cost.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.273-278
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• 2007

In the next generation wireless mobile network, various methods are studied to offer interworking and mobility between various radio networks. To offer these harmoniously, network adaptation methods based on IP is generalized, and specifications of host-based mobility method with Mobile IPv4 and Mobile IPv6 to offer IP's mobility are defined in IETF specially. However, it is insufficient to satisfy quality of service that should be offered in wireless mobile network environment. Alternatively studies about Network-Based Mobility of Proxy Mobile IPv4, Proxy Mobile IPv6 etc. are preceded. This paper presents optimum plan that can offer mobility in the next generation radio transfer communication network by comparing and analyzing IP mobility methods divided by Host-based Mobility and Network-based Mobility.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.348-352
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• 2008

In distributed computing paradigm, mobile surrogate systems migrates from on host in a network to another. However, Mobile surrogate system have not gained wide acceptance because of security concerns that have not been suitably addressed yet. In this paper, we propose a security framework based on Grid Proxy Gateway for mobile Grid service. The current Grid Security Infrastructure is extended to mobile computing environments. The surrogate host system designed for mobile Personal Digital Assistant (PDA) users can access the certified host and get his proxy credential to launch remote job submission securely.