• Progress in Superconductivity and Cryogenics
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• v.12 no.1
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• pp.28-31
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• 2010

A magnetic field calculation method for toroidal type winding which has circular section was developed. At first, the equation for magnetic field by single filament coil was extended using numerical integration to estimate the entire interesting region of solenoid, especially winding region itself. And then, the magnetic field by toroidal arrangement of solenoids was computed with a coordinate transformation of vector fields. The superconducting magnet with toroidal arrangement can be made up of several tens of solenoid type double pancake windings for some applications such as superconducting magnetic energy storage system(SMES). In this system, the field calculation on the high-Tc superconducting(HTS) tape itself is very important because the entire system can be reached to a fault by magnetic stress of conductor or the critical current of superconducting tape can be dramatically reduced under its self field condition. To make matters worse, 3-dimensional analysis is indispensable for this type of magnet and the most of commercial programs with finite element method can be taken too much time for analysis and design. In this paper, a magnetic field calculation method for toroidal type winding with circular section was induced.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4722-4730
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• 2022

This paper introduces a new point depletion-based source term calculation code named BESNA (Bateman Equation Solver for Nuclear Applications), which is aimed to estimate nuclide inventories and source terms from spent nuclear fuels. The BESNA code employs a new modified CE/CM (Constant Extrapolation - Constant Midpoint) predictor-corrector scheme in depletion calculations for improving computational efficiency. In this modified CE/CM scheme, the decay components leading to the large norm of the depletion matrix are excluded in the corrector, and hence the corrector calculation involves only the reaction components, which can be efficiently solved with the Talyor Expansion Method (TEM). The numerical test shows that the new scheme substantially reduces computing time without loss of accuracy in comparison with the conventional scheme using CRAM (Chebyshev Rational Approximation Method), especially when the substep calculations are applied. The depletion calculation and source term estimation capability of BESNA are verified and validated through several problems, where results from BESNA are compared with those calculated by other codes as well as measured data. The analysis results show the computational efficiency of the new modified scheme and the reliability of BESNA in both isotopic predictions and source term estimations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6274-6281
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• 2015

Radio-based train control system has driving headway shortening effect by real-time train interval control using two-way radio communication between onboard and wayside systems, and reduces facility investment because it does not require any track-circuit. Automatic train protection(ATP), the most significant part of the radio-based train control system, makes sure a safe distance between preceding and following trains, based on real-time train location tracing. In this paper, we propose the overall ATP train interval control algorithm to control the safe interval between trains, and preprocessing-based speed profile calculation algorithm to improve the processing speed of the ATP. The proposed speed profile calculation algorithm calculates the permanent speed limit for track and train in advance and uses as the most restrictive speed profile. If the temporary speed limit is generated for a particular track section, it reflects the temporary speed limit to pre-calculated speed profile and improves calculation performance by updating the speed profile for the corresponding track section. To evaluate the performance of the proposed speed profile calculation algorithm, we analyze the proposed algorithm with O-notation and we can find that it is possible to improve the time complexity than the existing one. To verify the proposed ATP train interval control algorithm, we build the train interval control simulator. The experimental results show the safe train interval control is carried out in a variety of operating conditions.

• Proceedings of the KSEEG Conference
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• 2001.04a
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• pp.111-114
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• 2001

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.224-229
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• 2001

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.109-117
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• 2015

This paper proposes the comparison results of various optimal power flow algorithms (OPF) to calculate the locational marginal prices (LMP) of the unreduced full scale Korean transmission system. Five different types of optimal power flow models are employed: Full AC OPF, Cubic AC OPF, Quadratic AC OPF, Linear AC OPF and DC OPF. As the results, full AC OPF and cubic AC OPF model provides LMP calculation results very similar to each other while the calculation time of cubic AC OPF model is faster than that of the Full AC OPF. Other simplified OPF models, quadratic AC OPF, linear AC OPF and DC OPF offer erroneous results even though the calculation times are much faster than the Full AC OPF and the Cubic AC OPF. Given the condition that the OPF models sometimes fail to find the optimal solution due to the severe complexity of the Korean transmission power system, the Full AC OPF should be used as the primary OPF model while the Cubic AC OPF can be a promising backup OPF model for the LMP calculations and/or real-time operation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.2
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• pp.70-74
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• 2018

Social infrastructure such as production, transportation, gas, and electrical facilities would be degraded according to time and those facilities might need more maintenances, repairing, and management as time goes by. Especially, in the case of a power transformer, it is important to diagnose the transformer in order to avoid malfunction and failure because they could cause enormous damage. The economic as well as technical aspects of a transformer management must be considered while it is operated. Therefore, the concept of asset management should be applied as an advanced method of transformer management. Asset management refers to a series of processes to make a plan of maintenance and conservation of a power transformer considering the soundness, investment cost, and importance of equipment. It is important to apply the asset management considering calculation of a lifetime loss. In this paper, the lifetime loss calculation method of asset management for a power transformer is suggested.

• Progress in Medical Physics
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• v.13 no.4
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• pp.234-241
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• 2002

The depth electrode technique, especially using the occipito-temporal route is widely used in the clinic, since it is known to be the most precise method about the invasive study of the mesial temporal lobe epilepsy. The depth electrode with the occipito-temporal route has been applied with manual calculation of MR images. Inherently there are some factor causing significant errors due to geometrical axis alignment, such as miss alignment of horizontal or vertical cutting line. In order to correct it in manually, it takes a long time. In this study, authors has developed the software for automate calculation of MRI wording for instance calculation and for the no time delaying operation. Authors could show that this software is useful for the clinic after applying if for 33 cases of the patients.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.72-77
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• 2008

About 25% of overall energy use of Korea had been spent in buildings. It is crucial to acknowledge the importance of saving energy in buildings. In order to save energy, it is important to predict accurate energy use. There are numerous energy simulation program that predicts both energy load and energy use. The problem of the energy simulation program is that it holds too many input variables, and it needs experts to model a building. So, our purpose of this study is to develop the simplified thermal load calculation program for building energy analysis which eliminates coordinates of building components instead of using full coordinates by using DOE2. Since the engine of the program is DOE2, we verified the validity of S-DOE by comparing peak heating & cooling load results and annual energy use results. The results shows that there are little difference between VisualDOE and S-DOE. Also it showed that S-DOE took less time to input variables than VisualDOE. These results reveals that the application of S-DOE is possible to accurately predict energy load and energy use of the building and still have strong point that it takes less time to analyse building energy.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1097-1108
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• 2017

Accurate calculation of the conduction and switching losses of a power electronic converter is required to achieve the efficiency of the converter. Such calculation is also useful for computing the junction temperature of the switches. A few models have been developed in the articles for calculating the switching energy losses during switching transitions for the given values of switched voltage and switched current. In this study, these models are comprehensively reviewed and investigated for the first time for ease of comparison among them. These models are used for calculating the average amount of switching power losses. However, some points and details should be considered in utilizing these models when switched current or switched voltage presents time-variant and alternative quantity. Therefore, an applicable technique is proposed in details to use these models under the above-mentioned conditions. A proper switching loss model and the presented technique are used to establish a new and fast method for obtaining the average switching power losses in any type of power electronic converters. The accuracy of the proposed method is evaluated by comprehensive simulation studies and experimental results.