• KSII Transactions on Internet and Information Systems (TIIS)
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• v.1 no.1
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• pp.1-17
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• 2007

This paper proposes and analyzes a scalable and an efficient cluster based group key management protocol by introducing identity based infrastructure for secure communication in mobile wireless sensor networks. To ensure scalability and dynamic re-configurability, the system employs a cluster based approach by which group members are separated into clusters and the leaders of clusters securely communicate with each other to agree on a group key in response to changes in membership and member movements. Through analysis we have demonstrated that our protocol has a high probability of being resilient for secure communication among mobile nodes. Finally, it is established that the proposed scheme is efficient for secure positioning in wireless sensor networks.

• Journal of KIISE:Information Networking
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• v.30 no.4
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• pp.545-558
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• 2003

It is expected that per-user customized services are widely used in next generation Personal Communication Network. The ultimate goal for personalized service is the Virtual home Environment (VHE) providing ´same-look-and-feel´ services for the subscriber wherever he roams to. To provide personalized services for each call, per-user service profiles are frequently referenced, so efficient service profile management is essentially required. To realized the VHE, typically two schemes, can be employed; One is Intelligent Network based service control and the other is a full replication scheme that always replicates profile in user´s current zone. The first scheme is referred as Central scheme and th second scheme is the modified replication scheme of IMT-2000, we refer to as Follow-Me Replication Unconditional (FMRU). Since the Central scheme only depends on the service cal rate and the FMRU is merely dependent on the movement rate, it is apparent that FMRU scheme outperforms the Central scheme if the call to mobility ratio (CMR) is large, and vice versa. In this paper, we propose a new service profile replication schemes, Adaptive Follow-Me Replication (AFMR) that determine replication automatically according to the user´s CMR. We compared the performance of the AFMR with the non-adaptive Follow-Me Replication unconditional on Demand (FMRUD) scheme. Performance results indicate that as the CMR of a user changes AFMR adapts well compared to the existing schemes.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.16-27
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• 2014

In this paper, we propose an efficient grid based routing scheme using the location information in order to reduce the routing cost in mobile ad-hoc networks. In our proposed scheme, all nodes can be a candidate to forward messages to the specified destination node and reduce the management cost of head nodes because they do not exist. The intermediate nodes determine the next hop relaying messages on the basis of location relations between a node and a grid zone. The proposed scheme explores the routing path considering the direction of a node using the coordinate of a grid zone and neighbor node information. It also maintains the routing path considering connectivities among the nodes. In order to show the superiority of the proposed routing scheme, we compare it with the existing grid based routing scheme in terms of the overhead of message, the success rate of transmission.

• Journal of KIISE:Information Networking
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• v.31 no.5
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• pp.490-500
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• 2004

In mobile/wireless environment, mobility management is widely being focused as one popular researches. But, disruption happens when messages are exchanged between nodes as registration is made after handoff, and unnecessary traffic occurs because of the use of the Random-walk model, in which the probability for MN to move to neighboring cells is equal. In order to solve these problems, this study proposes a technique and algorithm for composing Directional Shadow Registration Region (DSRR) that provides seamless mobility. The core of DSRR is to prevent disruption and unnecessary traffic by minimizing the number o) neighboring cells with a high probability of handoff (AAAF). This study sensed the optimal time for handoff through regional cell division by introducing a division scheme, and then decided DSRR, the region for shadow registration, by applying direction vector (DV) obtained through directional cell sectoring. According to the result of the experiment, the proposed DSRR processes message exchange between nodes within the intra-domain, the frequency of disruptions decreased significantly compared to that in previous researches that process in inter-domain environment. In addition, traffic that occurs at every handoff happened twice in DSRR compared to n (the number of neighboring cells) times in Previous researches. As an additional effect, divided regions obtained from the process of composing DSRR filter MN that moves regardless of handoff.

• Journal of information and communication convergence engineering
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• v.7 no.4
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• pp.475-479
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• 2009

In ad hoc network, the scarce energy management of the mobile devices has become a critical issue in order to extend the network lifetime. Current research activity for the Minimum Energy Multicast (MEM) problem has been focused on devising efficient centralized greedy algorithms for static ad hoc networks. In this paper, we consider mobile ad hoc networks(MANETs) that could provide the reliable monitoring and control of a variety of environments for remote place. Mobility of MANET would require the topology change frequently compared with a static network. To improve the routing protocol in MANET, energy efficient routing protocol would be required as well as considering the mobility would be needed. In this paper, we propose a new method, the CACH(Context-aware Clustering Hierarchy) algorithm, a hybrid and clustering-based protocol that could analyze the link cost from a source node to a destination node. The proposed analysis could help in defining the optimum depth of hierarchy architecture CACH utilize. The proposed CACH could use localized condition to enable adaptation and robustness for dynamic network topology protocol and this provide that our hierarchy to be resilient. As a result, our simulation results would show that CACH could find energy efficient depth of hierarchy of a cluster.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.5
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• pp.888-908
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• 2011

The increasing demand from passengers in vehicles to improve safety, traffic efficiency, and comfort has lead to the growing interest of Wi-Fi based vehicle-to-infrastructure (V2I) communications. Although the V2I system provides fast and cost-effective Internet connectivity to vehicles via roadside Wi-Fi access points (APs), it suffers from frequent handoffs due to the high mobility of vehicles and the limited coverage of Wi-Fi APs. Recently, the Mobile AP (MAP) platform has emerged as a promising solution that overcomes the problem in the V2I systems. The main advantage is that MAPs may yield longer service duration to the nearby vehicles that have similar mobility patterns, yet they provide smaller link capacities than the roadside APs. In this paper, we present a new association control technique that harnesses available connection duration as well as achievable link bandwidth in high-speed vehicular network environments. We also analyze the tradeoff between two association metrics, namely, available connection duration and achievable link bandwidth. Extensive simulation studies based on real traces demonstrate that our scheme significantly outperforms the previous methods.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.2
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• pp.9-14
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• 2008

Mobile Ad-Hoc network is the network of mobile nodes which has no fixed infrastructure, and mobile node in MANET can move freely and communicate with each other. The location management is an important issue because location information of a mobile node is frequently changed in MANET. In this paper, we propose new quorum system applying the gravity of locality of mobile nodes adaptively by using the fuzzy-logic for the mobility of mobile nodes in order to manage location information of mobile nodes in MANET efficiently. The performance of the proposed scheme is evaluated by an analytical model and compared with those of existing UQS and DQS schemes.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.32-45
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• 2013

Globally, intelligent vehicles and telematics research and development through the integration of IT technology in the vehicle are significant increasing. Real-time data communication for intelligent transportation system (ITS) is very important. It collects real-time data from the vehicle and provides the information collected from ITS center. We propose an effective and secure communication scheme for these communication procedures. In particular, our proposed SIP-based MVPN reduces signaling cost and has many advantages in security aspects. In addition, our proposed scheme performs the mobility management applying NEMO (Network Mobility) for the communication between the vehicles. In other words, we propose an ITS communication mechanism of SIP-based mobile VPN and V2V NEMO. Finally, our performance analysis show that the ITS of SIP-based MVPN is significantly reducing the handoff signaling cost.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.283-292
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• 2002

This paper develops a scheme of resource management for guaranteeing QoS of realtime traffic in wireless mobile internet environments Mobile terminal has significant impact on the QoS originating mobility provided to a real-time application. The currently proposed MRSVP is not clear the boundary of resource reservation tregion and also can give rise to signal overhead to maintain sessions. To solve above problem, we propose the new reservation protocol, mobile cluster based H-MRSVP to combine MRSVP with moving cluster concept. In this paper, we analytically design our model for guaranteeing the QoS of realtime traffic and compare the three schemes: guard channel allocation schemes, DCA and our model. The performance measures are the probabilities of new call blocking, handoff dropping, resource utilization and service completion versus the system offered Erlang load. Consequently, Simulation indicate our model is more flexible than DCA in a view pint of channel utilization and gains the advantage over guard channel scheme with respects to the mobility.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.80-84
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• 2010

Data multicasting from a source to multiple sinks in wireless sensor networks is used to achieve both reducing communication costs and energy efficiency. Almost all existing schemes for the multicasting might be effectively performed by optimal construction of a multicasting tree between a source and multiple stationary sinks. However, in practical sensor applications, sinks could move around on the wireless sensor networks for own missions, such as scouting of soldiers and saving lives of victims by firefighters. Unfortunately, the sink mobility causes frequent entire reconstruction of the multicasting tree and thus it leads to exhaustion of battery power of sensors. Hence, we propose an energy-efficient multicast protocol to support multiple mobile sinks by the local multicast tree reconstruction, called Local Update-based geographic Multicasting for Mobile sinks (LUMM) for wireless sensor networks. Our simulation results show that our scheme for mobile sinks is more efficient in terms of energy resource management than other exist works.