• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.165.1-165.1
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• 2011

In the present study, two numerical methods were developed and compared for the performance prediction of the horizontal axis energy conversion turbine. The Blade Element Momentum Theory was adopted, and the rotating reference frame method for Computational Fluid Dynamics solver was also used. Hybrid meshing was used for the complex geometry of turbines. The analysis results using each method were compared to figure out a better method for the performance prediction.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1339-1342
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• 2005

The development of an accurate and energy saving pneumatic regulator that may be applied to a variety of practical pressure control applications is described in this paper. A novel modified pulse width modulation(MPWM) valve pulsing algorithm allows the pneumatic regulator to become energy saving system. A comparison between the system response of conventional PWM algorithm and that of the modified PWM(MPWM) algorithm shows that the control performance is almost the same, but energy saving is greatly improved by adopting this new MPWM algorithm. The effectiveness of the proposed control algorithm is demonstrated through experiments with various reference trajectories.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.5
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• pp.277-284
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• 2012

To meet the usage of discrete wavelet transform (DWT) on potable devices, this paper implements 2-level DWT using a reference many-core processor architecture and determine the optimal many-core processor. To explore the optimal many-core processor, we evaluate the impacts of a data-per-processing element ratio that is defined as the amount of data mapped directly to each processing element (PE) on system performance, energy efficiency, and area efficiency, respectively. This paper utilized five PE configurations (PEs=16, 64, 256, 1,024, and 4,096) that were implemented in 130nm CMOS technology with a 720MHz clock frequency. Experimental results indicated that maximum energy and area efficiencies were achieved at PEs=1,024. However, the system area must be limited 140mm2 and the power should not exceed 3 watts in order to implement 2-level DWT on portable devices. When we consider these restrictions, the most reasonable energy and area efficiencies were achieved at PEs=256.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.1
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• pp.15-22
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• 2001

In this paper, a VSC(Voltage Sag Corrector) is discussed for the purpose of power quality enhancement. A fast detecting technique of voltage sag is accomplished through the detection of instantaneous value on synchronous reference frame. A robust characteristic against the noise is available by inserting the first order low pass filter in the detection circuit. The formula and the filter design process is described properly with the mathematical equations. Because the VSC system supply the active power to load, it is required to design the proper size of the energy storage system, In this paper, the capacitor bank is used as an energy storage system, and the size of the capacitor is designed from the point of view of input/output energy as the output power rating and the amplitude and duration time of the voltage sag. The simulation is accomplished by PSCAD/EMTDC.

• Nuclear Engineering and Technology
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• v.31 no.1
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• pp.116-132
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• 1999

This study is intended to analyze the requirements of a buffer material that is one of the major components of the engineered barriers in a high-level radioactive waste repository. The characteristics of potential materials for the buffer in the repository were analyzed and a candidate material was selected. And, based on the current knowledge and the information from various sources, the requirements of a buffer material were evaluated. Finally its quantitative functional criteria on the generic viewpoint has been recommended to be supplied as a guideline for the development of the reference disposal concept and the related buffer material in Korea. The criteria are composed of seven major items, such as hydraulic conductivity, retardation capacity, swelling potential and swelling pressure, thermal conductivity, longevity, organic matter content, and mechanical properties.

• Nuclear Engineering and Technology
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• v.34 no.6
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• pp.610-618
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• 2002

A study of the conceptual data modeling to realize the decommissioning database on the HRR-1&2 was carried out. In this study, the current state of the abroad decommissioning database was investigated to make a reference of the database. A scope of the construction of decommissioning database has been set up based on user requirements. Then, a theory of the database construction was established and a scheme on the decommissioning information was classified . The facility information, work information, radioactive waste information, and radiological information dealing with the decommissioning database were extracted through interviews with an expert group and also decided upon the system configuration of the decommissioning database. A code which is composed of 17 bit was produced considering the construction, scheme and information. The results of the conceptual data modeling and the classification scheme will be used as basic data to create a prototype design of the decommissioning database.

• Nuclear Engineering and Technology
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• v.35 no.1
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• pp.35-44
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• 2003

The neutron induced nuclear data for Eu-153, Gd-155 and Cd-157 are calculated and evaluated in the high energy region. The evaluation procedure for deformed nuclei is setup by using Ecis-Empire codes. The energy dependent optical model potential parameters are searched based on the recent experimental data and applied up to 20 MeV. Optical model, full featured Hauser-Feshbach model and multistep direct and multistep compound model are used in the calculation. The direct-semidirect capture model and the direct coupled-channels contribution to discrete levels are introduced to improve the capture and inelastic scattering cross sections. The theoretically calculated cross sections are compared with the experimental data and the evaluated files. The model-calculated total and capture cross sections are in good agreement with the reference experimental data. The evaluated cross section results are compiled to ENDF-6 format and are expected to improve the ENDF/B-Vl.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.425-426
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• 2005

1. The oxide thickness on the fuelled test rods was within the following range from 7 ${\mu}m$ to 17 ${\mu}m$. In general, the HANA claddings showed better corrosion behavior than the two reference alloys (A-Cladding and Zr-4). 2. The weight gains of corrosion coupons were ranged from 21 to 56 mg/$dm^2$.

• Journal of the Korean Solar Energy Society
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• v.22 no.3
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• pp.11-20
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• 2002

This paper proposed a MPPT(Maximum Power Point Tracking) control algorithm for PV(Photovoltaic) array based on a modified constant voltage control MPPT algorithm at low insolation. This method which combined a reference voltage control and a constant voltage control algorithm. In contrast to the typical conventional MPPT algorithm, the proposed method have been obtained high efficiency and good performance in all insolation intensity. The proposed algorithm is verified through simulation and experiment.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.787-798
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• 2013

This paper proposes a special power circuit topology and its corresponding control strategy for an energy recovery power accumulator battery pack testing system (PABPTS), which is particularly used in electric vehicles. Firstly, operation principle and related parameter design for the system are illustrated. Secondly, control strategy of the composite power converter for PABPTS is analyzed in detail. The improved scheme includes a high accuracy charge and discharge current closed loop. active power reference for the grid-side inverter is provided by the result of multiplication between battery pack terminal voltage and test current. Simulation and experimental results demonstrate that the proposed scheme could not only satisfy the requirements for PABPTS with wide-range current test, but also could recover the discharging energy to the power grid with high efficiency.