• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1777-1783
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• 2013

We do research on the simulation of Doppler effect from a target's moving under the sea by Transmission Line Matrix modeling which is one of numerical methods on time domain. To implement the effect, the input signal was entered at a moving node according to a moving target's moving speed. The result had maximum 2.47% error compared with the theoretical value. And from simulation results with speed control of a moving target, we could also obtain resonable results within 0.63% error range.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.9
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• pp.459-464
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• 2006

The detent force by end-effect has an undesired influence on moving coil type Permanent Magnet Linear Synchronous Motor(PMLSM). So, the reduction of detent force by end-effect is especially required for the improvement of thrust characteristics. In this paper, in order to reduce detent force by end-effect, the auxiliary-teeth is installed at the end part of mover. It is also analyzed by Finite Element Analysis(FEA) and optimized by using neural network. By comparison, the detent force is reduced about 41.4[%] comparing to that of basic model.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.11-17
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• 2008

This paper proposes the USN node location recognition method with low power, which is the modified centroid method. The conventional Zigbee node location recognition is used to the three RSSI values from three beacons, respectively. When a person move with node, the moving speed of USN node doesn't fast. Therefore, one among three positions used to the value that it is a previous value. This method doesn't large the error in terms of the exact position. Using hand-off method, we get about 30% power advantage than the conventional centroid method. And Our monitoring system add the function that it is possible to search for the node region by color.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.8
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• pp.1388-1403
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• 2011

A vehicular ad-hoc network (VANET) consists of vehicles that form a network without any additional infrastructure, thus allowing the vehicles to communicate with each other. VANETs have unique characteristics, including high node mobility and rapidly changing network topology. Because of these characteristics, routing algorithms based on greedy forwarding such as greedy perimeter stateless routing (GPSR) are known to be very suitable for a VANET. However, greedy forwarding just selects the node nearest to the destination node as a relay node within its transmission range. This increases the possibility of a local maximum and link loss because of the high mobility of vehicles and the road characteristics in urban areas. Therefore, this paper proposes a reliability-improving position-based routing (RIPR) algorithm to solve those problems. The RIPR algorithm predicts the positions, velocities, and moving directions of vehicles after receiving beacon messages, and estimates information about road characteristics to select the relay node. Thus, it can reduce the possibility of getting a local maximum and link breakage. Simulation results using ns-2 revealed that the proposed routing protocol performs much better than the existing routing protocols based on greedy forwarding.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.461-465
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• 2007

MANET(Mobile Ad hoc Networks) is free-mobility formation of mobile nodes in the wireless networks. Generally, wireless networks has two main type of structures which Tree and Mesh. These general structure is difficult to do which connectivity, redundancy transmit and network continuant. In this paper, we would suggest a new ODDMRP(Ontology Doppler effect-based Dynamic Multicast Routing Protocol) technology for effective MANET which Ontology Doppler effect-based. ODDMRP consist of the parameters for node entropy when using Doppler effect which moving position of round node, moving time, and distribution chart in velocity also it express distance of destination node and property structure organization. It would be used to provide improvement to keep the optimal communication routing and also could be improve network stabilization, and continuation durability of connectivity.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.271-276
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• 2004

In this paper. dynamic behavior of the cracked beam under a moving mass is presented using the finite element method (FEM). Model accuracy is improved with the following consideration: (1) FE model with Timoshenko beam element (2) Additional flexibility matrix due to crack presence (3) Interaction forces between the moving mass and supported beam. The Timoshenko bean model with a two-node finite element is constructed based on Guyan condensation that leads to the results of classical formulations. but in a simple and systematic manner. The cracked section is represented by local flexibility matrix connecting two unchanged beam segments and the crack as modeled a massless rotational spring. The inertia force due to the moving mass is also involved with gravity force equivalent to a moving load. The numerical tests for various mass levels. crack sizes. locations and boundary conditions were performed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.93-95
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• 2014

In this paper, we proposed efficient forwarding path computing method using Context-Awareness Mobility Prediction Model. Context-Awareness Mobility Prediction Model is storing and classifying node's previous velocity and direction according to time in the hierarchical cluster structure. To overcome environment which node-to-node connection is broken off easily, the proposed algorithm calculate the connectivity formed matrix structure by comparing predicted velocity and direction, and use masking operation for selecting relay moving to destination. The proposed algorithm identified to show short delay by utilizing forwarding path which is continue node-to-node connection in the unstable situation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.4
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• pp.1187-1208
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• 2022

One of the main goals of wireless sensor networks (WSNs) is to utilize the energy of sensor nodes effectively and maximize the network lifetime. Thus, this paper proposed a routing protocol for WSNs based on virtual force disturbing mobile Sink node (VFMSR). According to the number of sensor nodes in the cluster, the average energy and the centroid factor of the cluster, a new cluster head (CH) election fitness function was designed. At the same time, a hexagonal fixed-point moving trajectory model with the best radius was constructed, and the virtual force was introduced to interfere with it, so as to avoid the frequent propagation of sink node position information, and reduce the energy consumption of CH. Combined with the improved ant colony algorithm (ACA), the shortest transmission path to Sink node was constructed to reduce the energy consumption of long-distance data transmission of CHs. The simulation results showed that, compared with LEACH, EIP-LEACH, ANT-LEACH and MECA protocols, VFMSR protocol was superior to the existing routing protocols in terms of network energy consumption and network lifetime, and compared with LEACH protocol, the network lifetime was increased by more than three times.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8A
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• pp.830-836
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• 2006

One of the seminal operation parameters of AODV is the node-to-node travel time of data, which is currently set to fixed value of 40 ms in the RFC3561 and widely used to compute other parameters such as the expected round-trip time of the connection setup message, etc. We have naturally thought the network performance could be improved by dynamically varying the node-to-node travel time with respect to the traffic condition in the networt rather than using the fixed value, which motivates this work. To this end, we apply the idea of using timestamp; every node places the current time in the message before sending it out, and the receiver node computes the node travel time based on the moving average algorithm by considering not only the current value but also the previous ones in an accumulated and exponentially decreasing fashion with time. We evaluate the performance of the proposed scheme in respect of the number of RREQ messages generated, throughput, and delay as a function of traffic load and node mobility, and compare the result with the original AODV scheme. The results show that the proposed scheme presents noticeable performance improvements, expecially under the condition of high node mobility and high traffic load.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.276-287
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• 2004

An ad hoc network is infra(Base Sstation or Access Point) free wireless mobile communication technology. Mobile nodes function as routers and servers in ad hoc networks. Many routing protocols for ad hoc network have been proposed. If any route is broken owing to moving node, source must repair broken route again. But route repair technology after route collapses is not suitable to transmit real-time data packet for QoS guarantee. So this paper presents route repair technology that prevents route from breaking. If intermediate node moves to critical section, the node issues handoff packet and sends the packet to the next node. After next node receives handoff packet, the node broadcasts route request packet to the previous node for intermediate node. Finally, even if intermediate node moves out of the routing region, the source can continuously transmit data packets to the destination through the new path.