• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1125-1136
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• 2010

Lately there exist increasing demands for online abnormality monitoring over trajectory stream, which are obtained from moving object tracking devices. This problem is challenging due to the requirement of high speed data processing within limited space cost. In this paper, we present a FADA (Fuzzy Anomaly Detection Algorithm) which constructs normal profile by computing mobility feature information from the GPS (Global Positioning System) logs of mobile devices in MANETs (Mobile Ad-hoc Networks), computes a fuzzy dissimilarity between the current mobility feature information of the mobile device and the mobility feature information in the normal profile, and detects effectively the anomaly behaviors of mobile devices on the basis of the computed fuzzy dissimilarity. The performance of proposed FADA is evaluated through simulation.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.425-430
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• 2007

Without the aid of stationary infrastructure, maintaining routing information for all nodes is inefficient in the Mobile Ad hoc Networks(MANET). It is more efficient when every time routing information is necessary that the source node broadcasts a query message to neighbour nodes. The source node using Ad hoc On-Demand distance Vector(AODV), which is one of the routing protocols of MANET, uses the Expanding Ring Search(ERS) algorithm which finds a destination node efficiently. In order to reduce the congestion of the network, ERS algorithm does not broadcast Route REQuest(RREQ) messages in the whole network. When the timer expires, if source node does not receive Route REPly(RREP) messages from the destination node, it gradually increases TTL value and broadcasts RREQ messages. Existing AODV cost a great deal to find a destination node because it uses a fixed NODE_TRAVERSAL_TIME value. Without the message which is added in existing AODV protocols, this paper measures delay time among the neighbours' nodes by making use of HELLO messages. We propose Adaptive ERS(AERS) algorithm that makes NET_TRAVERSAL_TIME optimum which apply to the measured delay time to NODE_TRAVERSAL_TIME. AERS suppresses the unnecessary messages, making NET_TRAVERSAL_TIME optimum in this paper. So we will be able to improve a network performance. We prove the effectiveness of the proposed method through simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.9
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• pp.3449-3467
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• 2015

A broadcast operation is the fundamental transmission technique in mobile ad-hoc networks (MANETs). Because a broadcast operation can cause a broadcast storm, only selected forwarding nodes have the right to rebroadcast a broadcast message among the one-hop and two-hop neighboring nodes of a sender. This paper proposes the maximum intersection self-pruning (MISP) algorithm to minimize broadcasting redundancy. Herein, an example is given to help describe the main concept of MISP and upper bounds of forward node have been derived based on induction. A simulation conducted demonstrated that when conventional blind flooding (BF), self-pruning (SP), an optimized link state routing (OLSR) multipoint relay (MPR) set, and dominant pruning (DP), are replaced with the MISP in executing Strong duplicate address detection (DAD), the performances in terms of the energy consumption, upper bounds of the number of forward nodes, and message complexity have been improved. In addition, to evaluate the performance in reference to the link error probability, P_e, an enhancement was achieved by computing a proposed retransmission limit, S, for error recovery based on this probability. Retransmission limit control is critical for efficient energy consumption of MANET nodes operating with limited portable energy where Strong DAD reacts differently to link errors based on the operational procedures.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.719-721
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• 2010

VoIP over MANET is an important IP phone technique used in mobile ad-hoc networks. VoIP system over wired networks is based on SIP, SIP UA and SIP server which process the users invite, register and so on. Since no base stations in MANETs to perform as SIP servers, VoIP service on MANETs is being done with tiny SIP server which is done on each node. In this paper, VoIP system is implemented with pseudo SIP server which can process 1 call based on modification of standard SIP server which is used on communication environment such as wired networks. The propesed system is performed well and compatible with SIP and SIP UA.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1109-1116
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• 2010

In this paper, some performance characteristics of VoIP(Voice over Internet Protocol) for MANET(Mobile Ad-hoc Networks) with simulation is studied and appropriate condition for implementation of VoIP service is suggested. VoIP simulator is implemented with NS(Network Simulator)-2. VoIP traffic for simulation is generated with some codecs of G.711, G.723.1, G.726-32, G.729A, GSM.AMR and iLBC. As simulation results for traffic transmission under $670{\times}670m$ 50node MANET environment, performance data for MOS(Mean Opinion Score), network delay, packet loss rate and transmission bandwidth are measured. Normalized analysis about measured results shows that maximum VoIP connection satisfying VoIP service quality condition is 15.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.444-446
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• 2021

MANETs(Mobile Ad-hoc Networks) are composed of mobile nodes that are not subordinate to fixed networks and have the feature that can form their own networks. they are used in various fields for specific goals. The mobility model in MANET can be applied in various ways depending on the purpose of usage. The random mobility model has the advantage of being simple and easy to implement, so it is being used the most. In a MANET, it is assumed that each node moves independently. The random movement model is a good model for expressing this independence of each node. However, it is insufficient to express the characteristics of all nodes with only random properties of individual nodes. This paper limits the stochastic mobility model applicable in MANET. we compare the proposed stochastic mobility model and the random mobility model. We confirm that the proposed mobility model is applied to the routing protocol to show improved characteristics in terms of energy consumption efficiency.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.809-816
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• 2005

MANET(mobile ad hoc network) cn be one of the access networks of BcN(broadband convergence network), and an user node requires address auto-configuration protocol for mu14i-hop environment. Some address auto-configuration protocols are proposed for independent MANET, but they don't consider BcN-accessable MANET environment. In this paper, new address auto-configuration protocol for wireless nodes is proposed. With this proposal, they ran configure their global addresses automatically in hybrid MANETs as BcN access networks. The autoconfiguration protocol modifies IPv6 NDP(neighbor discovery protocol) messages to deliver global prefix information to all wireless nodes, and avoids message boradcasting to minimize network overhead.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2861-2880
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• 2018

Mobile Ad hoc Networks (MANETs) have become a viable platform owing to their potential of providing communication without any pre-existing infrastructure and central administrating authority. Mutual support and co-operation among nodes are prerequisites for performing functions in such networks. The scarcity of resources makes it economical for nodes to conserve their resources and misbehave by avoiding participation in the network. Therefore, a mechanism is required to detect and handle such misbehaving nodes and promote co-operation in the network. Existing techniques for handling misbehaving nodes focus only on their current behaviour without considering the antecedent behaviour of nodes. In real world, a node may dynamically change its behaviour in accordance to its requirements. Hence, an efficient mechanism is required for providing security against such misbehaviour. This paper proposes an Adaptive Security Model which contemplates the present as well as anterior behaviour of nodes for providing security against dynamic node behaviour. The adaptivity of the model is nested in its ability to requite well-behaving nodes and penalize misbehaving ones in conformity with their overall behaviour. Simulation results indicate the efficiency of proposed scheme in securing the network from the menace of dynamic behaviour of nodes.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.221-227
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• 2008

The proposed zone-based self-organized clustering broadcasts neighbor information to only a zone with the same ID. Besides, the zone-based self-organized clustering with unique IDs can communicate securely even if the state transition of nodes in zone-based self-organized clustering is threatened by corrupted nodes. For this security, the Byzantine agreement protocol with proactive asynchronous verifiable secret sharing (AVSS) is considered. As a result of simulation, an efficiency and a security of the proposed clustering are better than those of a traditional clustering. Therefore, this paper describes a new and extended self-organized clustering that securely seeks to minimize the interference in mobile ad hoc networks (MANETs).

• Journal of Communications and Networks
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• v.14 no.4
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• pp.434-442
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• 2012

Several gateway selection schemes have been proposed that select gateway nodes based on a single Quality of Service (QoS) path parameter, for instance path availability period, link capacity or end-to-end delay, etc. or on multiple non-QoS parameters, for instance the combination of gateway node speed, residual energy, and number of hops, for Mobile Ad hoc NETworks (MANETs). Each scheme just focuses on the ment of improve only a single network performance, i.e., network throughput, packet delivery ratio, end-to-end delay, or packet drop ratio. However, none of these schemes improves the overall network performance because they focus on a single QoS path parameter or on set of non-QoS parameters. To improve the overall network performance, it is necessary to select a gateway with stable path, a path with themaximum residual load capacity and the minimum latency. In this paper, we propose a gateway selection scheme that considers multiple QoS path parameters such as path availability period, available capacity and latency, to select a potential gateway node. We improve the path availability computation accuracy, we introduce a feedback system to updated path dynamics to the traffic source node and we propose an efficient method to propagate QoS parameters in our scheme. Computer simulations show that our gateway selection scheme improves throughput and packet delivery ratio with less per node energy consumption. It also improves the end-to-end delay compared to single QoS path parameter gateway selection schemes. In addition, we simulate the proposed scheme by considering weighting factors to gateway selection parameters and results show that the weighting factors improve the throughput and end-to-end delay compared to the conventional schemes.