• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.7
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• pp.656-665
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• 1992

In this paper, the performance of the various multiple access techniques for the mobile computer network has been studiedi in the consideration of the charactersitics of the mobile cimmunication channel. In the case of the hidden node occurring. It could be seen that the performance of the code division multiple access (CDMA) technique with simultaneous access function is better than that of the other packet access methods such as carrier sendsed multiple access (CDMA), busy tone multiple access (BTMA) and idle signal multiple access (ISMA) in the view of the throughput and mean delay time. Also, it has been shown that the performance of the CDMA method is superior to that of other packet access techniques such as multiple access (CSMA), etc. when the fading effect or impulsive noise exists in the mobile channel, Especially, in the case of the distributed mobile network it has been shown that the receivertransmitter based CDMA method using the characteristics of CDMA effectively has better throughput and less mean delay time than the commontransmitter based CDMA technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11B
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• pp.987-996
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• 2006

In NEMO scenarios, mobile node's variety of movements and mobile router's point of attachment changes can result in handover. This handover process needs additional time to finish due to the multiple levels of indirection involved in NEMO. And the performance issues of mobile node's handover such as handover delay and packet loss in above cases haven't been studied thoroughly. So, in this paper, we define fast handover failure cases in hierarchical mobile IPv6 network based NEMO. We briefly described NEMO architecture and handover procedures of FMIPv6 and HMIPv6. And then, we classified mobile node or mobile router's movement pattern into several scenarios. Analysis for the fast handover classified NEMO scenarios, in terms of handover latency and packet delivery cost have been performed.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.81-84
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• 2005

Various design schemes for network using wireless sensor nodes have been widely studied on the several application areas ranging from the real world information collection to environmental monitor. Currently, the schemes are focused on the design of sensor network for low power consumption, power-aware routing protocol, micro miniature operating system and sensor network middleware. The indoor localization system that identifies the location of the distributed nodes in a wireless sensor network requires features dealing with mobility, plurality and other environmental constraints of a sensor node. In this paper, we present an efficient location system to cope with mobility of multiple mobile nodes by designing a location handler that processes location information selectively depending on the nodes' density in a specific region. In order to resolve plurality of multiple mobile nodes, a routing method for the location system is also proposed to avoid the occurrence of overlapped location data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3603-3618
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• 2022

The offloading method is important when there are multiple mobile nodes and multiple edge servers. In the environment, those mobile nodes connect with edge servers with different bandwidths, thus taking different time and energy for offloading tasks. Considering the system load of edge servers and the attributes (the number of instructions, the size of files, deadlines, and so on) of tasks, the energy-aware offloading problem becomes difficult under our mobile edge environment (MCE). Most of the past work mainly offloads tasks by judging where the job consumes less energy. But sometimes, one task needs more energy because the preferred edge servers have been overloaded. Those methods always do not pay attention to the influence of the scheduling on the future tasks. In this paper, first, we try to execute the job locally when the job costs a lower energy consumption executed on the MD. We suppose that every task is submitted to the mobile server which has the highest bandwidth efficiency. Bandwidth efficiency is defined by the sending ratio, the receiving ratio, and their related power consumption. We sort the task in the descending order of the ratio between the energy consumption executed on the mobile server node and on the MD. Then, we give a "suffrage" definition for the energy consumption executed on different mobile servers for offloading tasks. The task selects the mobile server with the largest suffrage. Simulations show that our method reduces the execution time and the related energy consumption, while keeping a lower value in the number of uncompleted tasks.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.4
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• pp.9-17
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• 2007

Network Mobility basic support protocol (NEMO Basic) extends the operation of Mobile IPv6 to provide uninterrupted Internet connectivity to the communicating nodes of mobile networks. The protocol uses a mobile router (MR) in the mobile network to perform prefix scope binding updates with its home agent (HA) to establish a bi-directional tunnel between the HA and MR. This solution reduces location-update signaling by making network movements transparent to the mobile nodes (MNs) behind the MR. However, delays in data delivery and higher overheads are likely to occur because of sub-optimal routing and multiple encapsulation of data packets. To manage the mobility of the mobile network, it is important to minimize packet overhead, to optimize routing, and to reduce the volume of handoff signals over the nested mobile network. This paper proposes en aggregate router-assisted route optimization (ARARO) scheme for nested mobile networks support which introduces a local anchor router in order to localize handoff and to optimize routing. With ARARO, a mobile network node (MNN) behind a MR performs route optimization with a correspondent node (CN) as the MR sends a binding update message (BU) to aggregate router (AGR) via root-MR on behalf of all active MNNs when the mobile network moves. This paper describes the new architecture and mechanisms and provides simulation results which indicate that our proposal reduces transmission delay, handoff latency and signaling overhead. To evaluate the scheme, we present the results of simulation.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.3
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• pp.1-11
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• 2013

This study developed the algorithm of location-based service for supplying the efficient tourism service to traveller using mobile device and applied it to the Jeonju HANOK village. First, the location service was advanced using algorithm coupling with GPS error range and travel speed in single line, and with GPS location and nearest neighbor method to line in multiple one. Also this study developed a program using DuraMap-Xr spatial engine for establishing topology to Node and Link in line automatically. And the foundation was prepared for improving travel convenience by programming location-based service technology to single and multiple lines based on Blackpoint-Xr mobile application engine.

• Advances in Computational Design
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• v.3 no.2
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• pp.191-200
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• 2018

Establishment of an efficient routing technique in multiple-input-multiple-output (MIMO) based mobile ad hoc network (MANET) is a new challenge in wireless communication system to communicate in a complex terrain where permanent infrastructure network implementation is not possible. Due to limited power of mobile nodes, a minimum power consumed routing (MPCR) algorithm is developed which is an integration of cooperative transmission process. This algorithm select relay node and support short distance communication. The performance analysis of proposed routing algorithm increased signal to noise interference ratio (SNIR) resulting effect of cooperative transmission. Finally performance analysis of the proposed algorithm is verified with simulated result.

• Journal of Information Processing Systems
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• v.7 no.1
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• pp.137-150
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• 2011

Mobile ad hoc networks are expected to be widely used in the near future. However, they are susceptible to various security threats because of their inherent characteristics. Malicious flooding attacks are one of the fatal attacks on mobile ad hoc networks. These attacks can severely clog an entire network, as a result of clogging the victim node. If collaborative multiple attacks are conducted, it becomes more difficult to prevent. To defend against these attacks, we propose a novel defense mechanism in mobile ad hoc networks. The proposed scheme enhances the amount of legitimate packet processing at each node. The simulation results show that the proposed scheme also improves the end-to-end packet delivery ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8A
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• pp.679-687
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• 2005

A mobile ad-hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. It is necessary to use bandwidth effectively because MANET has limited bandwidth. In this paper, we propose SMGS (source based multiple gateway selection routing protocol). In SMGS, each node estimates its expected life time (ELT) and if its ELT is larger than that of current gateway it becomes a candidate node. When a source node establishes a path, in each grid the candidate node will take the route request and be a gateway node for the each source node. The node that is expected to stay the longest time in the grid is selected so that we can reduce frequent gateway handoff, packet loss, and handoff delay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.777-785
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• 2009

In recent wireless sensor networks, stationary nodes and mobile nodes co-exist to provide a diverse service. However, because there are multiple mobile nodes located in the wireless sensor network, there is a potential for the instability due to the frequent network reconfiguration and the traffic caused by densely concentration of mobile nodes while mobile nodes are switching locations. In order to solve this problem, we propose the pumping node architecture to solve this traffic congestion problem due to the crowds of mobile nodes. The pumping node can be reduced heavy traffic by pumping through the backbone network caused by the densely concentration of the mobile nodes. As a result, the architecture reduces the traffic in the sensor network with high reliability.