• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1741-1747
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• 2010

The development of overload management systems for distribution transformers offers new opportunities for improving the reliability of distribution systems. It allows network planners to optimize the system resource utilization and investment cost. Such an improvement in the flexibility of the distribution network is only possible if the operator has more accurate knowledge of the realtime conditions of distribution transformers. In this paper, we present an improved overload decision system for distribution transformers using realtime monitoring data. Our study can be categorized into two parts: (a) improvement in the criteria for judging the overload conditions of distribution transformers and (b) development of an overload evaluation system using realtime monitoring data. In order to determine the overload criteria, overload experiments are performed on sample transformers; the results of these experiments are used to define the relationship between the transformer overload and the increase in the top-oil temperature. To verify the accuracy of the experimental results, field tests are performed using specially manufactured transformers, the loads and top-oil temperatures of which can be measured. For arriving at online overload decisions, we propose methods whereby the measured load curve can be converted into an overload characteristic curve and the overload time can be calculated for any load condition. The developed system is able to evaluate the overload for individual distribution transformers and calculate the losses using realtime monitoring data.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.339-344
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• 2019

In this paper, a digital home electric overload alarm system based on DSP for smart home automation which can minimize electrical fire damage caused by an home electrical overload was made experimentally. To verify the validity of the home electrical overload alarm technology, an electric overload alarm performance evaluation system which can artificially generate the electrical overloads was designed, developed, and constructed, and the effectiveness of the overload alarm developed by the overload test was verified. In particular, an overload test EMTP model based on EMTP-RV was developed, and simulation and measurement results obtained from the overload test were compared, and the reliability of overload performance verification results was confirmed.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.172-174
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• 2002

This paper proposes a new methodology for adequacy evaluation of composite power system considering an ambiguity of overload of transmission lines. Nodal arrival powers under considering an ambiguity of overload of transmission lines can be evaluated using the proposed method. Fuzzy set theory has been used in order to consider the permission level of overload of transmission lines. The problem of adequacy evaluation has been formulated using fuzzy linear programing. The effectiveness of the proposed method considering permissible overload of transmission lines has been demonstrated on the IEEE RTS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.506-514
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• 2010

Defense systems are needed to prevent catastrophic failures of a power grid due to cascaded events. Cascaded events can be occurred by power flow overload. Especially, it is the most dangerous problem that overload line is outage, because it can make the power system face danger of cascaded. In this paper, vulnerability evaluation for monitoring wide are outage is proposed using by configuration information of transmission systems. This method of vulnerability evaluation is considered direct effect and indirect effect of power flow, especially overload. What is more, it can be used when the configuration of power system changes, as simple fault occurs or maintenance of facility. In the case studies, the estimation and simulation network have been testified and analysed in PSSE and C programming.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.359-364
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• 2004

In this study, experiments were tried on the mixed-mode I+II single overloading model which changes the loading mode of overload and fatigue load. Aspects of deformation field in front of the crack which is formed by mixed-mode I+II single overloading were experimentally studied. Then the shape and size of mixed-mode plastic zone were approximately calculated. The propagation behavior of fatigue crack was examined under the test conditions combined by changing the loading mode. The behavior of fatigue cracks were greatly affected by shapes of plastic deformation field and applying mode of fatigue load. Accuracy of prediction and evaluation for fatigue life may be improved by considering all aspects of deformation and behavior of fatigue cracks.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.67-68
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• 2006

In this paper, we introduced about safety algorithm of transformer for MV/LV distribution customers using by fuzzy theory. Overload of transformer becomes different by surrounding temperature. And parameters about overload of transformer are connection each other. Therefore, we organize safety algorithm consider overload of transformer and surrounding temperature in this research. And we induce the relational expression of each parameters using experiment data of IEEE std C57.91-1995. Deduction of result used fuzzy reasoning. We guess the safety algorithm suggested in this paper shows the new direction that heavy electrical equipments including switchboard are going to develop in the future.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1242-1251
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• 2009

A DSMS(Data Stream Management System) in ubiquitous environment processes huge data that input from a number of sensor. The existed system is used with a load shedding method that is eliminated with a part of huge data stream when it doesn't process the huge data stream. The Load shedding method has to filter a part of input data. This is because, data completeness or reliability is decreased. In this paper, we proposed the overload prediction load balancing to maintain data completeness when the system has an overload. The proposed method predicts the overload time. and than it is decreased with data loss when achieves the prediction overload time. The performance evaluation shows that the proposed method performs better than the existed method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.11-16
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• 2004

This paper proposes the overload reduction method for the connection information audit processor in ATM switch. Based on this method, we design the simple IPC exchange method and non-stop auditing method for IPC loss. We evaluate the performance about the proposed Audit method. At the result of evaluation, we figure out that the p개posed audit method reduces the load of call control processor because of a fewer IPC and prevent stopping audit function for IPC loss because of requesting the lost connection information again. Therefore, we confirm that the proposed audit method can reestablish a Mismatched connection information with a little load and elevate correctness about audit function.

• Fashion & Textile Research Journal
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• v.21 no.2
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• pp.141-150
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• 2019

Online recommendation services help people search for an appropriate product among a huge assortment in stores that also minimize consumers' choice overload. People with a need for uniqueness are likely to prefer this online recommendation service based on individual needs and tastes. This study verifies the effect of consumers' choice overload and similarity avoidance in consumers' evaluation towards an online recommendation service with a focus on innovativeness and use comparability. Two-hundred consumers participated in this study and data were collected through an online survey firm. A mock retailer's webpage was created and showed six types of sneakers, which was presented as a result of product recommendation based on consumers' personal information. Data was analyzed using confirmatory factor analysis (CFA), analysis of variance (ANOVA), and regression analysis. The results show that people with a high similarity avoidance perceive an online recommendation service as an innovative and compatible service. They also perceive a high level of use compatibility for an online recommendation service, especially when it is difficult to choose a product under choice overload. Innovativeness and use compatibility of an online recommendation service increase behavioral intention. The results of this study can contribute to strategies to start online recommendation services from online retailers' websites that identify circumstances in which consumers can adopt innovative services in a positive manner.

• Journal of Energy Engineering
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• v.29 no.3
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• pp.74-85
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• 2020

This paper presents an algorithm that evaluated the overload influence by bus upon the distribution system by calculating the daily load curve of PEVs charging by bus based on the daily charging patterns of PEVs according to PEVs penetration scenarios. The proposed algorithm calculates the number of PEVs to estimate the number of households by bus; the probability density function of the charging start time of PEVs, considering driving characteristics of PEVs and the daily load curve of PEVs charging by bus considering battery characteristics according to PEVs penetration scenarios. To verify the evaluation of the overload influence by bus on the distribution system in terms of the proposed algorithm, the cases were reviewed on the target bus(apartment and detached houses) among the feeders of the distribution systems at Dongtan new-town in Korea.