• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.186-188
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• 2005

Because forest fire changes the direction according to the environmental elements, it is difficult to predict the direction of it. Currently, though some researchers have been studied to which predict the forest fire occurrence and the direction of it, using the remote detection technique, it is not enough and efficient. And recently because of the development of the sensor technique, a lot of In-Situ sensors are being developed. These kinds of In-Situ sensor data are used to collect the environmental elements such as temperature, humidity, and the velocity of the wind. Accordingly we need the prediction technique about the environmental elements analysis and the direction of the forest fire, using the In-Situ sensor data. In this paper, as a technique for predicting the direction of the forest fire, we propose the correlation analysis technique about In-Situ sensor data such as temperature, humidity, the velocity of the wind. The proposed technique is based on the clustering method and clusters the In-Situ sensor data. And then it analyzes the correlation of the multivariate correlations among clusters. These kinds of prediction information not only helps to predict the direction of the forest fire, but also finds the solution after predicting the environmental elements of the forest fire. Accordingly, this technique is expected to reduce the damage by the forest fire which occurs frequently these days.

• 전기학회논문지
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• 제66권2호
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• pp.261-284
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• 2017

This paper describes the results of a low-frequency oscillation analysis using data measured in PMU installed in the KEPCO system, and the comparison with eigenvalues computed from the linear model. The dominant oscillation modes are estimated by applying various algorithms. The algorithms are: the extended Prony method; multiple time interval parameter estimation method; subspace system identification method; and spectral analysis. From the measurement data, modes of frequency 0.68[Hz] and 0.92[Hz] were estimated, and modes of frequency 0.63[Hz] and 0.80[Hz] were computed from the eigenvalue calculation. There was a difference between the mode estimated from measurement data and that from the linear model. This is possibly because of an error in the dynamic data of the KEPCO system used in eigenvalue calculation. Because wide area modes exist in the KEPCO system, these modes should be monitored continuously for the reliable operation of the system. In order to prevent total blackouts caused by wide area oscillation, moreover, contingency analysis should be performed in relation to this mode and appropriate measures should be established.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.216-220
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• 2000

AC Superconducting Generators (ACSG) are featured by 3D magnetic flux distribution, which decreases in the direction of axis. For this reason, when ACSG is optimal designed, 3D magnetic field analysis is required. This paper proposes 2D Finite Element Analysis (FEA) results normalized by 3D FEA according to the position of armature coil and the ratio of field coil width to axial length in order to reduce the analysis time. By using the proposed data, the reasonable 3D FEA results of ACSG can be only predicted by 2D FEA results. The validity of the 3D FEA results is verified by comparison with the experimental results of 30kVA superconducting synchronous generator.

• 전기학회논문지
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• 제66권10호
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• pp.1445-1453
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• 2017

In this paper, we propose a fault detection model based on multi-layer neural network using data mining technique for faults due to boiler tube leakage in a thermal power plant. Major measurement data related to faults are analyzed using statistical methods. Based on the analysis results, the number of input data of the proposed fault detection model is simplified. Then, each input data is clustering with normal data and fault data by applying K-Means algorithm, which is one of the data mining techniques. fault data were trained by the neural network and tested fault detection for boiler tube leakage fault.

• 조명전기설비학회논문지
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• 제25권10호
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• pp.38-46
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• 2011

Recently, interests in renewable energy have gradually increased. Of various renewable energy, Photovoltaic system has the properties affected by weather. This paper discusses the economic evaluation based on insolation data analysis. Real insolation data were obtained by radiation measurement device installed in projected photovoltaic system site during 20 months. Obtained real insolation data were standardized using clear day analysis. Standardized data are greater than obtained real insolation data and were used as parameters of RETScreen for the economic evaluation. In results, capacity(30[kW]) of soon cheon is shown the most B/C(1.20). Applied methods have effectively done to develop photovoltaic system.

• 대한전기학회논문지:전력기술부문A
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• 제52권10호
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• pp.571-576
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• 2003

XML Web Service based on internet can cause problems on transmission speed and data error. Also system analysis results simulated by several different research groups can hardly have reliability because of error data that come from improperly managed files. In order to solve this problems, algorithm sever using XML Web Service is shared on the internet so widely that various application programs based on basic analysis module with a united IO can be developed. And also XML Dataset DB is interacted with XML Web Service, which prevents propagation of error data. It causes to improve reliabilityon the load flow analysis result and solve the problems on data error or transmission speed that can possibly come from internet.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.58-60
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• 2009

This paper deals with force characteristic analysis of linear switched reluctance motor using dynamic simulation. First, we calculated flux density of linear switched reluctance motor according to position. Second, analyzed normal force from flux density of linear switched reluctance motor according to position. Also, analysis result compares with data that is derived through a finite element analysis, and proved validity. However, linear switched reluctance motor has non linear characteristic, hence, analysis of propulsion force do not easy using analytical method. Therefore, we presented dynamic characteristic analysis model which is consisted at motor and sensor signal part, etc., and substitute circuit constant that get using magnetic equivalent circuit method, we confirmed propulsion force.

• International Journal of Safety
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• 제8권2호
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• pp.9-14
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• 2009

This paper describes analysis of risk voltage for grounding electrode where earth leakage current is injected. To assess risk voltage of grounding electrode, the grounding simulator and CDEGS program were used to obtain measured data and theoretical results of this study. The grounding simulator was composed of a hemispherical water tank, AC power supply, a movable potentiometer, and test grounding electrodes. The shapes of grounding electrode model was ground rod. The potential rise was measured by grounding simulator, and the touch and step voltages were computed by CDEGS program. As a consequence, the potential rise of ground rod abruptly decreases with increasing the distance from the grounding electrode to the point to be tested. The touch voltage above the ground rod was low, but the step voltage was high. The measured results were compared with the computer calculated data and were known in good agreement.

• 대한통합의학회지
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• 제10권3호
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• pp.37-52
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• 2022

Purpose : The purpose of this meta-analysis was to evaluate the effects of electrical stimulation on patients with non-specific low back pain. Methods : Domestic databases were gathered from studies that conducted clinical trials associated with electrical stimulation and its impact on pain of non-specific low back patients. A total of 681 studies were identified, with 12 studies satisfying the inclusion data. The studies consisted of patient, intervention, comparison, outcome, and study design (PICO-SD). The search outcomes were items associated with low back pain. Cochrane risk of bias 2 (RoB 2) was used to evaluate the quality of 12 randomized controlled trials. Effect sizes (Hedges's g) in this study were computed as the corrected standard mean difference (SMD). A random-effect model was used to analyze the effect size because of the high heterogeneity among the studies. Egger's regression and 'trim-and-fill' tests were carried out to analyze the publication bias. Cumulative meta-analysis and sensitivity analysis were conducted to analyze the effect according to the sample size and the consistency of the effect size. Results : The following factors had a large overall effect size (Hedges's g=1.28, 95 % CI=.20~2.36) involving electrical stimulation on non-specific low back pain. The subgroup analysis all showed a statistical difference in the types of study design, electrical stimulation, and assessment tool. No statistically significant difference was found in the meta-regression analysis. Publican bias was found in the data. Conclusion : The findings in this study indicate that electrical stimulation interventions have a positive effect on patients with non-specific low back pain. However, due to the low quality of studies and publication bias, the results of our study should be interpreted cautiously.

• 한국안전학회지
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• 제20권3호
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• pp.53-57
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• 2005

This paper presents development of a classification system for an electrical fire investigation. In order to reduce an electrical fires and establish detailed prevention plans, the collection of an electrical fire causes and base data are very important. Based on this data, a new classification system for an electrical fire investigation was developed and the direction to the classification system was suggested by fundamental analysis. All of the collected information is analyzed by bottom-up method. Criteria items which based on base data were categorized to classify items. The classification of items were found out as follows : basic condition fire scene condition, fire sign, fire cause. Particularly, the fire cause category is classified. A new developed classification system for an electrical fire investigation will be used to analyse electrical fires easily and efficiently.