• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.684-690
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• 2006

This paper proposes a message transmission model for hard real-time communications of periodic messages on a switched Ethernet and also proposes an algorithm to schedule the messages to be transmitted within their deadlines. The proposed scheduling algorithm is a distributed one and is peformed by the source and the destination nodes without the modification of the operational features of the standard Ethernet switch. When a new periodic message needs to be transmitted, it is first checked whether it can be scheduled on both the transmission and the reception links without affecting the already-scheduled messages, and a feasible schedule is made for the new message if it is schedulable. The proposed scheduling algorithm guarantees the transmission of periodic messages within their deadline and allows flexible message transmission on a hard real-time switched Ethernet through the dynamic addition of new periodic messages during run-time.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.1
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• pp.86-93
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• 2006

The TAM(Topographic Attentive Mapping) network based on a biologically-motivated neural network model is an especially effective one for pattern analysis. It is composed of of input layer, category layer, and output layer. Fuzzy rule, for input and output data are acquired from it. The TAM network with three pruning rules for reducing links and nodes at the layer is called fuzzy TAM network. In this paper, we apply fuzzy TAM network to pattern analysis of core competency model for subcontractors of construction companies and show its usefulness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.889-898
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• 2000

In order to support various broadband multimedia servies in the future, we designed a well balanced WDM backbone network. In Korean network traffic environment, six regional centers are selected, link capacities between the regional centers are estimated from the PDI traffic model, and the overall network configuration is designed for the all-optical backbone network. Also, we designed a basic configuration to be able to protect minimum communication capability against link failure. A simulation study is carried out to verify the desired performance of the designed WDM backbone network. Simulation results show that performance of the backbone network is well balanced to support various communication services in Korea in the mid 2000s

• KSCI Review
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• v.1 no.2
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• pp.73-94
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• 1995

In this paper, design of efficient NDB(Network Data Base) for the activation plan of chain information network. The DB structure build up, logical structure, store structure, physical structure, the data express for one's record, and the express using linked in the releation of data. Also express as hierarchical model on the DSD(Data Structure Diagram) from the database with logical structure. Each node has express on record type, the linked in course of connective this type, the infuence have efficent of access or search of data, in the design for connection mutually a device of physical, design for database, and construction a form of store for logical. Also activation of chain information network of efficent, using POS(Point Of Sale) system in OSI(Open Systems Interconnection) environment for network standardization, and build up network a design for system.

• KIISE Transactions on Computing Practices
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• v.23 no.2
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• pp.122-127
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• 2017

The data link layer operates reliable internode communication in the OSI reference model. Generally, the forward error correction (FEC) method is used in the data link layer of the wireless sensor network (WSN) environment that has a high frequency of errors. However, the FEC method consumes a significant amount of energy due to its high error correction rate, which negatively affects the networks' lifespan. In contrast with battery-based technology, energy is regularly recharged in the solar-powered WSN to meet higher energy needs than required for basic operation of existing nodes. By efficiently utilizing this surplus energy, the proposed energy-aware FEC method can reduce the data loss rate with no decrement of the network lifetime. The method employs a trade-off relationship between the energy and data loss rate by adjusting the parity length in the FEC method to the energy state in each node. The performance of the proposed scheme was verified through a simulation.

• Journal of Internet Computing and Services
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• v.15 no.4
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• pp.1-8
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• 2014

In wireless body sensor system(WB-SNSs), unlike existing sensor network system, the size of device is small and amount of battery is considerably limited. And various channel environments can be made by link channel characteristic, human movements, sensor placements, transmission power control(TPC) algorithms and so on. In this paper, therefore we take diverse experiments with totally considerated environments to overcome these restrictions and to manage the energy efficiently and find the value of target received signal strength indicator(RSSI) based on diverse factors such as human movements, sensor placements, and TPC algorithms. And we conduct analysis in terms of energy consumption and packet delivery rate(PDR) based on the experimental results. Through these analysis, we compare and evaluate the efficiency according to setup values of Target RSSI and Target RSSI range suitable for wireless body sensor network system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.193-199
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• 2010

In this paper, we propose a new metric to measure the dynamic connection states of Ad Hoc network. The new metric measures the total path break up time $\sum_{i}T_i$, where $T_i$ is the time period during which maximum cluster distance exceeds the radio range. $T_i$ can be calculated from the maximum cluster distance function of time, which can be computed from the node position samples of mobility model. The proposed metric can be used as a total system metric as well as an individual connection metric.

• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.261-277
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• 2005

We propose the PAD (Power Aware Data-centric Routing Protocol), which finds minimum energy routes and prolongs network life-time, for the data-centric sensor networks. Firstly, the PAD discovers the minimum energy Property graph by removing redundant communication links. The proposed a1gorithm to find the minimum energy property graph is faster, simpler and easier to implement than existing aIgorithms. Secondly, the PAD runs the DDBF (Distributed Data-centric Bellman-Ford Algorithm) to determine routing paths between a base node and all sensor nodes. The DDBF selves the drawbacks of the distributed bellman-ford algorithm, i.e. slow convergence and a possible cyclic routing path. Since the PAD is a fully distributed algorithm with low overhead, it can be used in various kinds of resource limited sensor network applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3086-3097
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• 1996

Generally, the performance of the computer network may differ according to various parameters like routing, bandwidth and timers. Since the network system requirements may widely very according to specific application, computer network must be tailored at tailored at the design starge by selection of appropriate protocols and assignment of degfault parameter. However, since the condition under which a network actually operates may change from that considered at the design stage, control and managment action are required to adjust the network parameter so that the perforance of network is satisfied.

• Journal of the Korea Society of Computer and Information
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• v.1 no.1
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• pp.25-36
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• 1996

We have analyzed the reliability of failure models In grid topology circuit switched networks. These models are grid topology circuit_ switched networks. and each node transmits packets to object node using flooding search routing method. We hypothesized that the failure of each link Is Independent. We have analyzed for the performance estimation of failure models It using joint probability method to the reliability of a small grid topology circuit switched network. and compared analytic output with simulated output. Also. We have evaluated the reliability of networks using call blocking Probability occurred in circuit switched networks.