• Journal of Korea Multimedia Society
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• v.3 no.3
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• pp.320-332
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• 2000

Web consists of the grand virtual system which is made of all connected computers network. We can solve the huge problem which requires high quality in cost performance and powerful computing power to use a numerous idle state system on internet as process it parallel. However, we have to consider heterogeneous computing resources, accessibility, and reliability to carry out parallel system on global environment, not network but whole Internet. In this paper, We the WebImg system which has the power of web computing, and show the flexible task allocation strategy in heterogeneous hosts. Also, we evaluate its performance, moreover the proposed task allocation strategy supplies fault tolerance by controlling host situation at any time.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.4
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• pp.280-284
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• 2016

Stability and reliability of a power system in many respects depend on the condition of power transformers. Essential devices as power transformers are in a transmission and distribution system. Being one of the most expensive and important elements, a power transformer is a highly essential element, whose failures and damage may cause the outage of a power system. To detect the power transformer faults, dissolved gas analysis (DGA) is a widely-used method because of its high sensitivity to small amount of electrical faults. Among the various diagnosis methods, Rogers diagonsis method has been widely used in transformer in service. But this method cannot offer accurate diagnosis for all the faults. This paper proposes a fault diagnosis method of oil-filled power transformers using PNN(Probability Neural Network) based Rogers diagnosis method. The test result show better performance than conventional Rogers diagnosis method.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.102-107
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• 2011

LED-based lighting motivated by significant energy savings provides an opportunistic development of widespread free-space optical communications. Their transceivers have a variety of competitive advantages over RF including high bandwidth density, reliability, lower energy consumption, and long lifetime. But, it is difficult for existing buildings and structures such as ships and vehicles to install the communication cable to the ceiling. In this paper, controller area network (CAN)-based LED lighting communication systems were proposed. Results indicate the viability of developing inexpensive CAN interface modules and transceivers might be embedded in lighting products to support the indoor wireless networking.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2488-2511
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• 2015

Data redundancy has high impact on Wireless Sensor Network's (WSN) performance and reliability. Spatial and temporal similarity is an inherent property of sensory data. By reducing this spatio-temporal data redundancy, substantial amount of nodal energy and bandwidth can be conserved. Most of the data gathering approaches use either temporal correlation or spatial correlation to minimize data redundancy. In Collective Prediction exploiting Spatio Temporal correlation (CoPeST), we exploit both the spatial and temporal correlation between sensory data. In the proposed work, the spatial redundancy of sensor data is reduced by similarity based sub clustering, where closely correlated sensor nodes are represented by a single representative node. The temporal redundancy is reduced by model based prediction approach, where only a subset of sensor data is transmitted and the rest is predicted. The proposed work reduces substantial amount of energy expensive communication, while maintaining the data within user define error threshold. Being a distributed approach, the proposed work is highly scalable. The work achieves up to 65% data reduction in a periodical data gathering system with an error tolerance of 0.6℃ on collected data.

• Journal of Distribution Science
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• v.17 no.2
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• pp.35-42
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• 2019

Purpose - There is little research on the market of foreign infant education materials. So, it is needed to deeply examine the development and preference factors of foreign infant education materials. Therefore, this study presents a future method and model for analyzing the important variables of buying foreign infant education materials. Research design, data, and methodology - The conjoint analysis method and model of this paper is used as follows. Conjoint analysis method is possible to derive the attributes to be analyzed through the model of the preferred factors, and then to derive the sub-attributes of the attributes. Results - This study derived preference attributes between brand benefit, equity (brand image, loyalty, awareness), distribution network (department store, specialty stores, discount store, internet mall), and service quality (tangibles, reliability, responsiveness, assurance, empathy) in infant education materials conjoint model. Conclusions - Since the opening of the education market in Korea, parents have a high education level due to low birth rate. The advantages of the conjoint analysis method have been extended to the study of infant education materials. Based on this, this paper will identify important attributes that are considered in preference of foreign infant education materials and help to establish and implement future marketing strategies.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.314-317
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• 2004

With the advance of network and software infrastructure, Grid-computing technology on a cluster of heterogeneous computing resources becomes pervasive. Grid computing is required a coordinated use of an assembly of distributed computers, which are linked by WAN. As the number of grid system components increases, the probability of failure in the grid computing is higher than that in a traditional parallel computing. To provide the robustness of grid applications, fault detection is critical and is essential elements in design and implementation. In this paper, a OGSA based process fault-detection services presented to provide high reliability under low network traffic environment.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.116-122
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• 2006

Most of the multimedia applications require strict quality of service (QoS) guarantee during the communication between a single source and multiple destinations. This gives rise to the need for an efficient QoS multicast routing strategy. Determination of such QoS-based optimal multicast routes basically leads to a multi-objective optimization problem, which is computationally intractable in polynomial time due to the uncertainty of resources in Internet. This paper describes a network model for researching the routing problem and proposes a new multicast tree selection algorithm based on genetic algorithms to simultaneously optimize multiple QoS parameters. The paper mainly presents a QoS multicast routing algorithm based on genetic algorithm (QMRGA). The QMRGA can also optimize the network resources such as bandwidth and delay, and can converge to the optimal or near-optimal solution within few iterations, even for the networks environment with uncertain parameters. The incremental rate of computational cost can close to polynomial and is less than exponential rate. The performance measures of the QMRGA are evaluated using simulations. The simulation results show that this approach has fast convergence speed and high reliability. It can meet the real-time requirement in multimedia communication networks.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.1
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• pp.27-33
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• 2007

Hard turning on modern lathes becomes a realistic replacement for many grinding applications. Because CBN tools are expensive, excessive tool wear can eliminate economic advantages of hard turning. This paper describes a study of investigating the cutting force and the characteristics of tool wear in hard turning of hardened steels, AISI 52100. Cutting forces generated using CBN tools have been evaluated. The radial thrust cutting force was the largest among three cutting force components. It increased dramatically as a result of progressive tool wear. On the other hand, the result shows significantly different wear characteristics between high CBN and low CBN. Backpropagation neural network was used for the estimation of tool wear. The networks were achieved the reliability of 96.3% even when the spindle speed and feed rate are changed.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.1-7
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• 2011

The UAV(Unmanned Aerial Vehicle) which is remotely operating with long endurance in high altitude must have a very reliable propulsion system. The precise fault diagnostic system of the turboprop engine as a propulsion system of this type UAV can promote reliability and availability. This work proposes a diagnostic method which can identify the faulted components from engine measuring parameter changes using Fuzzy Logic and quantify its faults from the identified fault pattern using Neural Network Algorithms. It is found by evaluation examples that the proposed diagnostic method can detect well not only single type faults but also multiple type faults.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.21-26
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• 2005

We propose a fully converged Ethernet and TDM transport system. Developed Ethernet and TDM convergence system can support not only L2 VPN service and premium multimedia service based on MPLS protocol but also TDM leased line service, simultaneously. Developed convergence system can provide high reliability for Ethernet packet due to support protection and restoration function of circuit based networks. Evaluation for Ethernet and TDM path was successfully performed to show the typical application of the proposed system in the legacy networks.