• Title, Summary, Keyword: Differential Peak Correction Method

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Determination of Attenuation Collection Methods According to the Type of Radioactive Waste Drums (방사성폐기물드럼 종류별 감쇠보정방법의 결정)

  • Kwak, Sang-Soo;Choi, Byung-I1;Yoon, Suk-Jung;Lee, Ik-Whan;Kang, Duck-Won;Sung, Ki-Bang
    • Journal of Radiation Protection and Research
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    • v.22 no.4
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    • pp.309-317
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    • 1997
  • The measured radioactivity of gamma-emitting radionuclides in each radioactive waste drum using the non-destructive waste assay method is underestimated than real radioactivity in radioactive waste drum because the gamma-rays are attenuated within the medium. Therefore, the measured radioactivity should be corrected for the attenuation of gamma-rays. For the correction of the attenuation of gamma-rays, the attenuation correction method should be applied differently by considering the distribution and density of medium in radioactive wastes drum generated from nuclear power plants. In this study, the model drums were fabricated for simulating five types of radioactive waste drums generated from nuclear power plant and the optimum methods of the attenuation correction were experimentally determined to analyze the activity of radionuclides in the waste drum accurately using the segmented gamma scanning system. With the determination of the attenuation correction methods from the experimental results the transmission method and the average density method for the miscellaneous waste drum, the transmission method and the differential peak absorption method for the shielded miscellaneous waste drum were used to measure the density of medium in waste drums. Also, the average density method and the differential peak absorption method for the spent resin drum, the paraffin solidified drum, and the spent filter drum were used.

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Daily Electric Load Forecasting Based on RBF Neural Network Models

  • Hwang, Heesoo
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.13 no.1
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    • pp.39-49
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    • 2013
  • This paper presents a method of improving the performance of a day-ahead 24-h load curve and peak load forecasting. The next-day load curve is forecasted using radial basis function (RBF) neural network models built using the best design parameters. To improve the forecasting accuracy, the load curve forecasted using the RBF network models is corrected by the weighted sum of both the error of the current prediction and the change in the errors between the current and the previous prediction. The optimal weights (called "gains" in the error correction) are identified by differential evolution. The peak load forecasted by the RBF network models is also corrected by combining the load curve outputs of the RBF models by linear addition with 24 coefficients. The optimal coefficients for reducing both the forecasting mean absolute percent error (MAPE) and the sum of errors are also identified using differential evolution. The proposed models are trained and tested using four years of hourly load data obtained from the Korea Power Exchange. Simulation results reveal satisfactory forecasts: 1.230% MAPE for daily peak load and 1.128% MAPE for daily load curve.

Design of Uplink Initial Ranging Algorithm for Large-Cell Coverage Fixed Wireless Communication System (광범위 고정형 무선 통신 시스템을 위한 상향 링크 초기 레인징 기법 설계)

  • Lee, Kyung-Hoon;Hwang, Won-Jun;Choi, Hyung-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.7A
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    • pp.569-580
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    • 2012
  • In this paper, an enhanced initial ranging algorithm for large-cell coverage fixed wireless communication system is proposed. In typical wireless communication system such as WiBro, because a round-trip delay between a transmitter and a receiver is within one OFDM (Orthogonal Frequency Division Multiplexing) symbol duration, a frequency-domain differential correlation method is generally used. However, the conventional method cannot be applied due to an increase of a maximum time delay in large-cell system. In case of an accumulative differential method, estimation errors can occur because of frequent sign transitions. In this paper, therefore, we propose an algorithm which can estimate a total timing offset in a ranging channel structure for 15 km cell. The proposed method can improve performance by sign comparison based sign error correction rule between the estimated values and using a weighting scheme based on channel correlation, the number of accumulations, and the noise reduction effect in normalization process. Also, it can estimate the integer timing offset of symbol duration by comparing peak-powers after compensating for the fractional timing offset of symbol duration.

Comparison of the Correction Methods for Gamma Ray Attenuation in the Radioactive Waste Drum Assay (방사성폐기물드럼 핵종분석에서 감마선 감쇠보정 방법들의 비교 평가)

  • Ji Young-Yong;Ryu Young-Gerl;Kwak Kyoung-Kil;Kang Duck-Won;Kim Ki-Hong
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.4 no.3
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    • pp.275-284
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    • 2006
  • In the measurement of gamma rays emitted from the nuclide in the radioactive waste drum, to analyze the nuclide concentration accurately, it is necessary to use the proper calibration standards and to correct for the attenuation of the gamma rays. Two drums having a different density were used to analyze the nuclide concentration inside the drum in this study. After carrying out the system calibration, we measured the gamma rays emitted from the standard source inside the model drum with changing the distance between the drum and the detector. The measured values were corrected with the three kinds of gamma attenuation correction methode, as a results, the error was less than 10 % in the low density drum and less than 25 % in the high density drum. The measured activity in the short distance was more accruable than in the long distance. The transmission correction for the mass attenuation showed good results(very Low error) compared to the mean density and the differential peak correction method.

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