• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2230-2231
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• 2008

최근에 국제유가의 급상승과 코토의정서 발의에 따른 대외적인 환경여건 변화로 인해 국내에서는 재생에너지 보급사업 및 에너지절감기술 관련 정책과 신기술이 활발히 추진되고 있다. 본 논문에서는 전기설비간의 주 동맥인 케이블 선정에 있어 케이블 굵기를 달리 하는 조건에 따라 전력손실량 변화의 실험값을 모의시험장치를 이용하여 취득하였고 이를 비교분석함으로 써 케이블 부문에서 에너지절감의 이론적 근거를 실증하였다. 또한, 수자원공사 수도사업장 중 취수장 전력시스템을 모델로 전력계통해석프로그램(PTW)을 이용하여 케이블 굵기 변화에 따른 전력손실량 변화를 모의하고 경제성분석을 통해 기존 케이블의 굵기 선정 방법을 재 고찰하고자 한다.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.6
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• pp.224-229
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• 2003

An ultra high frequency (UHF) coupler possessing ultra wide band (UWB) characteristics ranging from hundreds of MHz to several GHz is desirable for the detection of the partial discharge (PD) pulses because the pulses propagate with rise time shorter than one nanosecond in a gas-insulated substation (GIS). Thus, the authors have proposed a log-periodic antenna for GIS PD detection. Various parameters of the coupler such as frequency bandwidth, coupler gain, radiation pattern, and coupler geometry were considered throughout the simulations. The experiments for the detection characteristics of the coupler were carried out in the mock-up GIS chamber. The results indicated that the detection characteristics of the coupler are dependent on the installation angle of the coupler, the position of the coupler in the hand hole and the existence of the spacer.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.6
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• pp.236-240
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• 2003

The UWB UHF coupler for GIS PD detection requires a balun (balance to unbalance transformer) to show its inherent UWB characteristics. In order to reduce the size of the balun and to make it practical in the conventional GIS, a novel tapered coaxial balun with a dielectric was proposed for the UWB UHF coupler. The performance of the proposed balun was verified through a series of simulations, measurements and experiments. As a result, both the conventional balun and the proposed balun, which has a length equal to one third of that of the conventional balun, demonstrated good S11 characteristics, whereas the efficiency of the proposed balun increased as much as about 30% in comparison to the conventional one.

• Journal of the Ergonomics Society of Korea
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• v.16 no.2
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• pp.101-122
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• 1997

Our recent work on virtual environments and virtual displays is reviewed, including our efforts to establish the Virtual Environment Research, Interactive Technology, And Simulation (VERITAS) facility and our research on spatial hearing. VERITAS is a state-of -the-art multisensory facility, built around the ${CAVE}^{TM}$ technology. High-quality 3D audio is included and haptic interfaces are planned. The facility will support technical and non-technical users working in a wide variety of application areas. Our own research emphasizes the importance of auditory stimulation in virtual environments and complex display systems. Experiments on auditory-aided visual target acquistion, sensory conflict, sound localization in noise, and loxalization of speech stimuli are discussed.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.136-139
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• 2004

It is widely known that the ultra high frequency (UHF) method that detects the electromagnetic wave of the PD pulses in the gas insulated space is one of the most competitive methods for its high sensitivity. From the above point of view, this paper describes the propagation characteristics of GIS PD signals measured with ultra wide band (UWB) GIS PD detecting system in which PD signals are detected into the dual UHF band. The UWB PD detection system consists of the UWB UHF coupler, the UWB low noise amplifier (LNA) and the oscilloscope. The dual bands for PD signals are 0.5-2GHz(full band) and 1-2GHz(high band). As results, propagation characteristics of GIS PD signals were measured in the mock-up GIS bus and it was found that the propagation characteristics of the high band showed a better result in accordance with the infernal configuration of the GIS bus than those of the full band.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.178-181
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• 1996

The Outflow facility of eye ball provides crucial informations in the diagnose of ophthalmological glaucoma. Tn this study an ophthalmic outflow facility measuring device is developed and experimentally tested. This system employs pressure sensors and linear positioning device to regulate solution reservoir height, the pressure of eye ball. The experimental result show that the system works well even in harsh environment so that it can be implemented in ophthalmic practice as well as in biomedical research.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.137-141
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• 2022

To inspect the power facility faults using artificial intelligence, it need that improve the accuracy of the diagnostic model are required. Data augmentation skill using generative adversarial network (GAN) is one of the best ways to improve deep learning performance. GAN model can create realistic-looking fake images using two competitive learning networks such as discriminator and generator. In this study, we intend to verify the effectiveness of virtual data generation technology by including the fake image of power facility generated through GAN in the deep learning training set. The GAN-based fake image was created for damage of LP insulator, and ResNet based normal and defect classification model was developed to verify the effect. Through this, we analyzed the model accuracy according to the ratio of normal and defective training data.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.353-363
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• 2023

The STELLA-2 is a large-scale sodium thermal-hydraulic integral effect test facility and supports the development of PGSFR. The facility adopted Pump Simulation Loop System (PSLS) concept for the mechanical sodium pump in the reference reactor to control and to measure the primary sodium flow. Since the component (mechanical pump) is replaced by the loop, it is very important to evaluate the similarity between the pump and the loop. In this paper, to simulate the characteristic of the mechanical sodium pump, the pressure loss along the various options of the loop was evaluated and the comprehensive validity of each design options was analyzed. Using the similarity criteria based on the Richardson number and Euler number conservation, the PSLS design was finalized and the result was within the acceptable error range. Finally, the result of this study was used for construction of the overall facility, STELLA-2.

• Korean Management Science Review
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• v.12 no.2
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• pp.63-75
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• 1995

The uncapacitated facility location problem considered here is to determine facility location sites, minimizing the total cost of establishing facilities and serving customer demand points which require primary and back-up services. To solve this problem effectively, we propose two things in this study. First, we propose an idea of Benders' decomposition approach as a solution method of the problem. Second, we implement the problem on GAMS. Using GAMS (general Algebraic Modeling System) can utilize an mixed-integer programming solver such as ZOOM/XMP and provide a completely general automated implementation with a proposed solution method.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.3892-3901
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• 2021

The pressure drop of a moisture separator in a steam generator is the important design parameter to ensure the successful performance of a nuclear power plant. The moisture separators have a wide range of operating conditions based on the arrangement of them. The prediction of the pressure drop in a moisture separator is challenging due to the complexity of the multi-dimensional two-phase vortex flow. In this study, the moisture separator test facility using the air/water two-phase flow was used to predict the pressure drop of a moisture separator in a Korean OPR-1000 reactor. The prototypical steam/water two-phase flow conditions in a steam generator were simulated as air/water two-phase flow conditions by preserving the centrifugal force and vapor quality. A series of experiments were carried out to investigate the effect of hydraulic characteristics such as the quality and liquid mass flux on the two-phase pressure drop. A new prediction model based on the scaling law was suggested and validated experimentally using the full and half scale of separators. The suggested prediction model showed good agreement with the steam/water experimental results, and it can be extended to predict the steam/water two-phase pressure drop for moisture separators.