• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1726-1734
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• 1993

This paper propose a survivable communication network design process using node degree that augments the usual traffic flow and cost analyses with previously ignored topological survivability and computing time considerations. At first, decide a initial topology, and then measure a throughput of network. If the throughput is smaller than the required traffic, add edge to the optimum place by using minimum node degree and link distance. Otherwise, drop useless edge by using maximum node degree, link distance and link utilization. This process is repeated until throughput equals to the required traffics. This Process designs a survivable communication network with the minimized cost and computing time and usual traffic flow. The design proceses that minimized computing time are freely select initial topology and easily design a large network. And these results of algorithm are compared with the Kris and Pramod's in order to analyses the perfmance of the designed network.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.3
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• pp.268-274
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• 2013

In this paper, the performance analysis of optics-based sensor node localization using ToF (Time of Flight) scheme is conducted. Generally, the position of the sensor node is calculated on the base station. And the base station scans neighboring sensor nodes with a laser. The laser which is reflected from one sensor node, however, can be reached to the base station at different angles according to the scanning resolution. This means that the error of the reached angle can increase and one node may be recognized as different nodes. Also the power of laser can decrease because the laser signal spread. Thus the sensor node which is located at a long distance from the base station cannot be detected. In order to overcome these problems which can be occurred in localization using ToF, the beam spot, the scanning resolution, the size of reflector and the power of laser at the sensor node were analyzed. It can be expected that the consequence of analysis can be provided in acquisition of accurate position of sensor node and construction of optics-based sensor node localization system.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.156-162
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• 2020

Wireless Sensor Network (WSN) field is mainly studied to monitor and characterize large-scale physical environments to track various environmental or physical conditions, such as temperature, pressure, wind speed and humidity. WSN can be used in various applications such as wild surveillance, military target tracking and monitoring, dangerous environmental exploration and natural disaster relief. We design probabilistic mobile models that apply to mobile ad hoc network mobile environments. A probabilistic shift model proposed by dividing the number of moving nodes and the distance of travel into two categories to express node movement characteristics. The proposed model of movement through simulation was compared with the existing random movement model, ensuring that the width and variation rate of the first node node node node (FND) was stable regardless of the node movement rate. In addition, when the proposed mobile model is applied to the routing protocol, the superiority of network life can be verified from measured FND values. We overcame the limitations of the existing random movement model, showing excellent characteristics in terms of energy efficiency and stable in terms of changes in node movement.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.423-434
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• 2007

Vehicular ad-hoc network (VANET), a kind of mobile ad-hoc network (MANET), is a key technology for building intelligent transportation system (ITS). VANET is automatically and temporarily established through vehicle-to-vehicle communication without network infrastructure. It has the characteristics that frequent changes of network topology and node density are occurred and messages are disseminated through several relay nodes in the network. Due to frequent change of network topology and node density, however, VANET requires an effective relay node selection scheme to disseminate messages through the multi-hop broadcast. In this paper, we propose a contention window based multi-hop broadcast scheme for VANET. Each node has an optimized contention window and competes with each other for a relay node. The experimental results show that the proposed scheme has a better performance than the distance-based deterministic broadcast scheme in terms of message propagation delay and network traffic.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.12-21
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• 2013

This study developed searching network reduction algorithm for reduce shortest path searching time. Developed algorithm is searching nodes that have the including possibility of less weights path than temporal path that consists minimum number of nodes and minimum sum of the straight line distances. The node that has the including possibility of shortest path is the node that the sum of straight line distance from start node and straight line distance to target node is less than the value that temporary path's weights divided by minimum weights units. If searching network reconstitutes only these nodes, the time of shortest path searching will be reduced. This developed algorithm has much effectiveness that start node and target node is close in large network.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.131-138
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• 2008

Mobile Ad hoc NETworks (MANETs) refer to autonomous networks in which wireless data communications are established between multiple nodes in a given coverage area without a base station or centralized administration. Because of node mobility and limited battery life, the network topology may changes frequently. Selecting the most reliable path during route discovery process is important to improve performance in ad hoc networks. In this paper, an enhanced routing protocol based on AODV(Ad hoc On-demand Distance Vector routing) by monitoring variation of receiving signal strength is proposed. New metric function that consists of node mobility and hops of path is used for routing decision. For preventing route failure by node movement during data transmission, a new route maintenance named as LRC (Local Route Change) is presented. If the node movement is detected, the routing agent switches path to its neighbor node in LRC. Simulation results show that the performance of the proposed routing scheme is superior to previous AODY protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4B
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• pp.378-385
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• 2011

The three-dimensional triangulation algorithm that the beacon nodes can be allocated to dynamically in not the experimental region but the practical region is suggested, and the performance of the localization system adapting the suggested algorithm is analyzed. The suggested algorithm adapts the computation method of the three dimensional point that the surfaces of three spheres overlapped, while the traditional triangulation algorithm adapts the computation method of the two dimensional point that three circles are overlapped in order to compute the distance between beacon nodes and mobile node that means a radius. In addition to this, to analyze the performance of the localization system adapting the suggested algorithm, first of all, the allocation layout of beacon nodes is made, and the allocation layout is modeled by selection of ten random distance values between mobile node and beacon nodes for computer simulation of the practical model. Next, the two dimensional coordinator of mobile node that is calculated by the suggested algorithm and the traditional triangulation algorithm is compared with each other. The localization measuring performance about three dimensional coordinator(z axis) of the suggested algorithm is also obtained by comparing with that of the practical model.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.103-117
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• 2009

In MANET(Mobile Ad-Hoc Network), providing security to routing has been a significant issue recently. Existing studies, however, focused on either of secure routing or packet itself where malicious operations occur. In this paper, we propose SRPPnT(A Secure Routing Protocol in MANET based on Malicious Pattern of Node and Trust Level) that consider both malicious behavior on packet and secure routing. SRPPnT is identify the node where malicious activities occur for a specific time to compose trust levels for each node, and then to set up a routing path according to the trust level obtained. Therefore, SRPPnT is able to make efficient countermeasures against malicious operations. SRPPnT is based on AODV(Ad-Hoc On-Demand Distance Vector Routing). The proposed SRPPnT, from results of the NS-2 network simulation. shows a more prompt and accurate finding of malicious nodes than previous protocols did, under the condition of decreased load of networks and route more securely.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.81-86
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• 2013

In this paper, the parameter identification for localization scheme for the optics-based micro sensor node is conducted. We analyzed short measurement range problem which can be occurred in optical based micro sensor node localization method using a time of flight. And we set up the theory for distance and maximum reflected laser power to overcome the problem by identifying hardware parameters like laser power, effective area of MEMS CCR, sensitivity of photodetector, and so on. Experimental results of measurement of maximum reflected laser power were compared with results of the theory. By using the theory, we can identify hardware parameters of localization scheme to measure particular position of the optics-based micro sensor node.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.491-499
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• 2017

The Information & Communication Technology (ICT) and the Internet of Things (IoT) have become the major issues in Republic of Korea recently. While RS-232, Zigbee, and WiFi-related technologies are used in the ICT-based systems, we focus on the Power Line Communication (PLC) in this paper. By carrying out OPNET simulations, we've implemented the PLC Router Node Model, PLC Terminal Node Model, PLC Link Model, and PLC Palette Model and executed the simulations arranging 20 holds within the range of 400m (20m apart). As a result, we confirmed that the slient node problem had occurred at the point of 200m-2000m (as of 2016) distance preventing further communications. However, the control group, by contrast, was able to carry out the communications by installing a router. We expect that this paper will contribute to the development of a foundation technology which will saves costs by performing the simulation prior to building actual large-scale ICT Complex in the future work.