• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.219-228
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• 2012

As the wireless Internet become more widely accessible, variety of Internet services can be used without limitation of location. However, existing mobility management methods such as MIP and PMIP of IETF requires the load of heavy protocol stack on the mobile nodes or the addition of components such as LMA and MAG. In this paper, we proposed the location management technique in the PMIPv6 and Fast Handover technique. according to the moving pattern of the node, the location management technique proposed in order to adjust the paging area dynamically. The Fast Handover technique applied MIH technology and it reduced the handover signal processing time between heterogeneous network. The location management cost in the environment which the node moves in order to evaluate this and handover delay time was calculate. The proposal technique was efficiently more evaluated than PMIPv6 with the smallest 29% and maximum 83%.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.411-416
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• 2007

The General security method of wireless network provides a confidentiality of communication contents based on the cryptographic stability against a malicious host. However, this method exposes the logical and physical addresses of both sender and receiver, so transmission volume and identification of both may be exposed although concealing that content. Covered address scheme that this paper proposes generates an address to which knapsack problem using super increasing sequence is applied, and replaces the addresses of sender and receiver with addresses from super increasing sequence. Also, proposed method changes frequently secret addresses, so a malicious user cannot watch a target system or try to attack the specific host. Proposed method also changes continuously a host address that attacker takes aim at. Accordingly, an attacker who tries to use DDoS attack cannot decide the specific target system.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.9
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• pp.197-206
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• 2020

Collaborative research in science applications based on HPC service needs rapid transfers of massive data between research colleagues over wide area network. With regard to this requirement, researches on enhancing data transfer performance between major superfacilities in the U.S. have been conducted recently. In this paper, we deploy multiple data transfer nodes(DTNs) over high-speed science networks in order to move rapidly large amounts of data in the parallel filesystem of KISTI's Nurion supercomputer, and perform transfer experiments between endpoints with approximately 130ms round trip time. We have shown the results of transfer throughput in different size file sets and compared them. In addition, it has been confirmed that the DTN cluster with three nodes can provide about 1.8 and 2.7 times higher transfer throughput than a single node in two types of concurrency and parallelism settings.

• The Transactions of the Korea Information Processing Society
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• v.6 no.9
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• pp.2460-2469
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• 1999

Recently, appearing of various wireless telecommunications services, the competitive power of paging service is requested. In this paper, two-way paging earth station for satellite was proposed and designed to enhance the competitive power of cost and technique, and the link budget of this two-way paging networks using Koreas at was discussed. To reduce the cost of remote station, the antenna and HPA size of Hub and remote station were differently designed, and an idea of power allocations of inbound and outbound carriers was proposed and utilized in this link budget of two-way earth station for using satellite. The results of this link budget were follows. At the 0.043% time rate of rain, antenna size of Hub and remote station were 3.7m and 1.2m, the HPA size of Hub and remote station were 10.37W and 2.0W, and power allocations of outbound and inbound were 84% and 16% respectively. At the 0.02% time rate of rain, the antenna size of Hub and remote station were 3.7m and 1.8m and power allocations of outbound and inbound were 63% and 37% respectively.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.875-882
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• 2002

The active packets unlike traditional IP packets should be executed at each active node along their path. To execute the active program at each active node, the active packets for an active program should go through the same active nodes and all packets are delivered without any loss. This paper presents the new active engine for every active packet which execute an active program to be routed through the same intermediate active nodes and to be delivered reliably. Proposed active engine requires fewer changes to existing IP protocols and guarantees the reliable delivery of the active packets. Moreover, even if the sender does not have any information about the intermediate nodes every active packet is routed through the same intermediate active nodes. The simulation results show that proposed active engine achieves an efficient transmission with high data delivery and low communication overhead compared with the other existing transmission protocols.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2022-2028
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• 2015

SpaceWire is a standard for high-speed links and networks between spacecraft components, which was invented for better, cheaper and faster on-board data handling in spacecraft. The standard defines timecode and its distribution which can be used for time synchronization among the nodes in a SpaceWire network. A timecode output from the time master which provides standard time over a SpaceWire network travels through links and routers to reach every nodes. While traveling, a timecode suffers from transmission delay and jitter which cause some difference in time synchronization among nodes. In this work, a simulator was developed using OMNeT++ to simulate the operation of a SpaceWire network and some analyses were performed on the transmission delay and jitter accompanied with a transmission of a timecode. The result will be used in the near future for the research of a precise time synchronization technique over a SpaceWire network.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.123-131
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• 2015

This paper aims to identify and clarify the cyber security risks and their interaction with the power system in Smart Grid. The EMS and other communication networks interact with the power system on a real time basis, so it is important to understand the interaction between two layers to protect the power system from potential cyber threats. In this study, the optimal power flow(OPF) and Power Flow Tracing are used to assess the interaction between the EMS and the power system. Through OPF and Power Flow Tracing based analysis, the physical and economic impacts from potential cyber threats are assessed, and thereby the quantitative risks are measured in a monetary unit.

• Journal of Broadcast Engineering
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• v.13 no.2
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• pp.245-250
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• 2008

Efficient service discovery mechanism is a crucial feature for the usability of a wireless ad-hoc network. A wireless ad-hoc network is a temporal network formed by a collection of wireless mobile nodes without the aid of any existing network infrastructure or centralized administration. We propose an efficient service discovery mechanism using non-disjoint multi-path routing protocol for a wireless ad-hoc network. Our scheme has advantages of not only multi-path routing protocol but also cross-layer service discovery. By simulation, we showed that faster route recovery is possible by maintaining multiple routing paths in each node, and the route maintenance overhead can be reduced by limiting the number of multiple routing paths and by maintaining link/node non-disjoint multi-path.

• Journal of Satellite, Information and Communications
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• v.1 no.1
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• pp.12-19
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• 2006

In this paper, we propose the bandwidth borrowing scheme which improves the performance of the cal admission control of the integrated GEO satellite networks. In general, target transmission rates of communications and streaming services are fixed, but data services do not have the target transmission rates. Therefore, we can control the transmission rates for data services flexibly according to the system loading situation. When the available bandwidth of the system is insufficient, the bandwidth borrowing scheme gives the bandwidth to request real time services by the transmission rates control of data services through packet scheduler. We make the queueing model for our system model and demonstrate the results through simulations. The simulation results show that there is a 8.7-35.2 dB gain at the total blocking probability according to the use of bandwidth borrowing scheme.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.27-32
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• 2012

In this paper, the wastewater treatment plant sludge proposed TN/TP sensor data collected an efficient monitoring system in order to implement status monitoring to build WiFi networks. Also we sludge concentration and TN/TP sensor data were collected from wastewater treatment plant. It is able to be monitored sensor data through smart devices(Smart phones, smart pad, tablet PC, etc.) and pc. In addition, when certain events occur immediately be able to cope by adding features to enable efficient and rapid processing, real-time status can be checked by ensuring improved user access and convenience. We has built a WiFi network for to transfer data efficiently. It proved its effectiveness by analysis of sensor communication network. Therefore, we have verified the usefulness of the proposed technology.