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Empirical Bayes Nonparametric Estimation with Beta Processes Based on Censored Observations

  • Hong, Jee-Chang;Kim, Yongdai;Inha Jung
    • Journal of the Korean Statistical Society
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    • v.30 no.3
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    • pp.481-498
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    • 2001
  • Empirical Bayes procedure of nonparametric estiamtion of cumulative hazard rates based on censored data is considered using the beta process priors of Hjort(1990). Beta process priors with unknown parameters are used for cumulative hazard rates. Empirical Bayes estimators are suggested and asymptotic optimality is proved. Our result generalizes that of Susarla and Van Ryzin(1978) in the sensor that (i) the cumulative hazard rate induced by a Dirichlet process is a beta process, (ii) our empirical Bayes estimator does not depend on the censoring distribution while that of Susarla and Van Ryzin(1978) does, (iii) a class of estimators of the hyperprameters is suggested in the prior distribution which is assumed known in advance in Susarla and Van Ryzin(1978). This extension makes the proposed empirical Bayes procedure more applicable to real dta sets.

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An Efficient Adaptive Polarimetric Processor with an Embedded CFAR

  • Park, Hyung-Rae;Kwag, Young-Kil;Wang, Hong
    • ETRI Journal
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    • v.25 no.3
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    • pp.171-178
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    • 2003
  • To improve the detection performance of surveillance radars with polarization diversity, we developed an adaptive polarimetric processor and compared it with other polarimetric processors. We derived our adaptive polarimetric processor, called the polarization discontinuity detector (PDD), from the generalized likelihood ratio (GLR) test principle for the unspecified target component. We derived closed-form expressions of its probabilities of detection and false alarm, and compared its performance to that of the adaptive polarization canceller (APC) and Kelly's GLR processor. The PDD had a performance similar to Kelly's GLR in Gaussian clutter, and both the PDD and Kelly's GLR, which have embedded constant false alarm rates (CFARs), outperformed the APC, especially when the target polarization state was close to the clutter's polarization state. The important difference is that the PDD is much simpler than Kelly's GLR for hardware/software implementation, because the PDD does not require a costly two-parameter filter bank to cover the unknown target polarization state as Kelly's GLR does.

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상부패드의 형상변경을 통한 증기터빈용 Anti-spragging 틸팅패드 저널베어링 개발(2-1)

  • Na, Un-Hak
    • 열병합발전
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    • s.50
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    • pp.18-22
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    • 2006
  • The tilting pad journal bearing has widely used to support high pressure/high rotating turbine rotors owing to their inherent dynamic stability characteristics. However, fatigue damages in the upper unlcaded pads and the break of locking pins etc. by pad spragging were continuously taken place in the actual steam turbines. The purpose of this paper is to develope a new bearing model that can prevent bearing damage problem effectively by pad spragging in a tilting pad journal bearing. A new bearing model which has a wedged groove is suggested from the studies of spragging mechanism performed by previously research works. The spragging characteristics of the upper unloaded pad are studied experimentally in order to verify the reliability of a new bearing model. It can be known that the phenomenon of pad spragging nearly does not occur in the new bearing model under the various experimental conditions. And it is observed that any kinds of bearing failures by pad spragging does not detect in the application of actual steam turbines.

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A study on KIMI-Theory (I) - The relationship between 'KI' and changes in body temperature - (기미론의 연구(I) - 부제 : 체온과 사기의 관계 -)

  • Lee, Han-Goo;Lee, Mi-Young;Lee, Je-Hyun
    • Korean Journal of Oriental Medicine
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    • v.1 no.1
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    • pp.419-431
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    • 1995
  • The common KIMI-Theory of Oriental medicine has evaluated clinical effects of herbal-drug based on KI, nature of berbs, and tastes. The KI in the theory consists of hotness, warm, cool and coldnes and also the Mi does five tastes such as sour, bitterness, sweet, spicy hotness and saltiness. However the KI does not mean thermal effect only. Thus we tried to determine skin and rectal temperatures at the same time for evaluating the relationship between KI and berbs. Male, adult Sprage-Dawly rat was chosen and berbal extract, 10g/Kg, was given orally once at 9:00 A.M. changes in rectal and skin temperatures were measured at 10, 30, 60, and 90 mins after the drug administratin. The changes in body temperatures are in greate deal of agreement of KI written in Herbology literatures.

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Output Control Simulation of Variable Speed Wind Power System using Real Data (실제 데이터를 이용한 가변속 풍력발전시스템의 출력제어 시뮬레이션)

  • Han, Sang-Geun;Park, Min-Won;Yu, In-Keun
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1342-1344
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    • 2002
  • Wind is a significant and valuable renewable energy resource. It is safe and abundant and can make an important contribution to future clean, sustainable and diversified electricity supplies. Unlike other sources of energy, wind does not pollute the atmosphere nor create any hazardous waste. In some countries wind energy is already competitive with fossil and nuclear power even without accounting for the environmental benefits of wind power. The cost of electricity from conventional power stations does not usually take full account of its environmental impact (acid rain, oil slick clean up, the effects of climate change, etc). In this paper, a transient phenomenon simulation method for Wind Power Generation System(WPGS) under real weather conditions has been proposed. The simulation method is expected to be able to analyze easily under various conditions with considering the sort of wind turbine, the capacity of system and the converter system. Wind turbine connected to the synchronous generator and power converter was simulated.

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A Study of Comparison between Internet Banking and Mobile Banking by Extending the TAM (기술수용모형을 이용한 인터넷 뱅킹과 모바일 뱅킹 이용의 차이에 관한 연구)

  • Lee Dong-Hyun;Kwak Soo-Hwan;Hwang Kyu-Seung
    • Journal of Technology Innovation
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    • v.14 no.1
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    • pp.201-225
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    • 2006
  • Technology Acceptance Model (TAM) considers perceived ease of use and perceived usefulness as the important determinants of user behavior regarding information technology. As an extension of TAM, this research examines perceived security as an additional determining variable to explain an individual's acceptance and use of mobile banking as well as internet banking. The results show that perceived ease of use does not affect the individual's attitude toward the use of mobile or internet banking, while perceived usefulness does. Furthermore, perceived security affects perceived usefulness in mobile banking, but not in internet banking. In addition, in mobile banking, perceived security is positively related to perceived usefulness, though perceived security is negatively related to attitude. Finally, the average scores of surveyed data for Internet banking are higher and significantly different than those for mobile banking.

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Trading rule extraction in stock market using the rough set approach

  • Kim, Kyoung-jae;Huh, Jin-nyoung;Ingoo Han
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 1999.10a
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    • pp.337-346
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    • 1999
  • In this paper, we propose the rough set approach to extract trading rules able to discriminate between bullish and bearish markets in stock market. The rough set approach is very valuable to extract trading rules. First, it does not make any assumption about the distribution of the data. Second, it not only handles noise well, but also eliminates irrelevant factors. In addition, the rough set approach appropriate for detecting stock market timing because this approach does not generate the signal for trade when the pattern of market is uncertain. The experimental results are encouraging and prove the usefulness of the rough set approach for stock market analysis with respect to profitability.

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Scaling of the Korean Version of the GMFM

  • Park, So-Yeon;Yi, Chung-Hwi
    • Physical Therapy Korea
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    • v.12 no.4
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    • pp.20-25
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    • 2005
  • The Gross Motor Function Measure (GMFM) is an internationally widely used outcome measure. The aim of this study was to evaluate the structural properties of the Korean version of GMFM using the Rasch Model, with regard to scoring within rehabilitation centers in Korea. GMFM data for 206 children with cerebral palsy were collected from 11 outpatient rehabilitation facilities by 29 pediatric therapists. The Winsteps software was used to refine the rating scale. This study suggests that the scoring categories of the Korean version of the GMFM should be collapsed from 0 (subject does not initiate task), 1 (subject initiates task), 2 (subject partially completes task), 3 (subject completes task) to 0 (subject does not initiate task), 1 (subject initiates or partially completes task), 2 (subject completes task) for better accuracy in estimating the gross motor function of children with cerebral palsy.

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