• Journal of Korean Society for Quality Management
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• v.19 no.1
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• pp.28-42
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• 1991

For a series or parallel system, though the component lifetimes have the absolutely continuous bivariate exponential distributions(ACBVE) by Block and Basu(1974), the common assumption that the component lifetimes are independent is used. The purpose of this paper, in this case, is to investigate the magnitude of the error caused by erroneous assumption, using the measure proposed by Klein and Moeschberger(1986). Estimation of the measure is conducted by maximum likelihood estimator(MLE) and those estimators are compared with corresponding jackknifed MLE through the Monte Carlo study.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.302-306
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• 2000

In case of applying electrokinetic remediation, magnitude of electric current is one of major factors for estimation of contaminant transport. In practice, electric current provide determination of electric conductivity based on specimen resistance. Electric current variation is produced during Electrokinetic remediation test. Electric current is decreased by expotential function according to time in condition of constant voltage. This can be interpreted as precipitation effect by OH$^{-10}$ generation in a cathode.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.157-162
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• 1998

Dynamic loads may arise from rotating parte of pump if they are insufficiently balanced. The magnitude of pump induced vibrations varies according to the weight, eccentricity, and unbalanced mass of pump. This is a study to estimate the pump induced vibration in time and frequency domain by transfer function. The transfer function has real and imaginary information of signals, and response function has also real and imaginary information. So the vibration force can be obtained from the response and transfer function by complex calculation. The amplitudes and components of 50Hp pump vibration force are suggested.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06d
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• pp.64-67
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• 1998

원격지간 화상회의 시스템에서 화자의 위치에 따른 카메라 제어를 위해서는 마이크로폰 배렬(Microphone Array)로 수음한 음성신호에 대해 각 마이크로폰간의 빠른 지연시간 추정이 요구된다. 본 연구에서는 음원위치 추정을 위한 지연시간(Time delay) 계산을 위해 AMDF(Average Magnitude Difference Function)를 적용하여 연산시간을 단축시키는데 목적을 두고 있다. 기본의 상호상관함수 (Cross-correlation )알고리즘 과 본 연구에서 적용한 AMDF 알고리즘을 비교하기 위해 SNR 10dB 와 20dB 인 200Hz, 500Hz, 1kHz, 2kHz의 정현파 합성신호와 단음절 음성신호에 대해 시뮬레이션을 행하였다. 시뮬레이션 결과 AMDF 알고리즘의 정확한 지연시간 추정을 확인하였다.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.545-548
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• 2008

In this study, the concept of safety impact assessment to achieve 'Design-for-Safety' in design phase is introduced. For this purpose, safety impact assessment model was devised and a methodology using the risk-based safety impact assessment approach for NATM of tunnel projects is suggested. The suggested methodology includes safety information survey, classification of safety impact factors caused by design and construction, and quantitative estimation of magnitude and frequency of safety impact factors. A real-world case study on the safety impact assessment of a tunnel construction project is also provided in the paper.

• The Journal of the Acoustical Society of Korea
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• v.17 no.2E
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• pp.10-15
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• 1998

Application of the Filtered-X LMS adaptive filter to active noise cancellation requires to estimate the transfer characteristics between the output and the error signal of the adaptive canceler. In this paper, we derive an adaptive cancellation algorithm and analyze is convergence behavior when the acoustic noise is assumed to consist of multiple sinusoids. The results of the convergence analysis of the Filtered-X LMS algorithm indicate that the effects of parameter estimation inaccuracy on the convergence behavior of the algorithm are characterize by two distinct components : Phase estimation error and estimated magnitude. In particular, the convergence of the Filtered-X LMS algorithm is show to be strongly affected by the accuracy of the phase response estimate. Simulation results of the algorithm are presented which support the theoretical convergence analysis.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.152-155
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• 2007

Efficiency and limitations of HAZUS-MH, a GIS based systematic and informative system developed by FEMA and NIBS for natural hazard loss estimations, are discussed by means of a pilot study in the Korean Peninsular. Gyeongsang-do has been selected for the test after careful reviews of previous studies including historical and modern seismicity in the peninsular. A ShakeMap for the selected scenario earthquake with magnitude 6.7 in Gyeongju area is prepared. Then, any losses due to the scenario event have been estimated using HAZUS. Results of the pilot test show that the study area may experience significant physical, economic and social damages. Detailed study in the future will provide efficient and crucial information to the decision makers and emergency agents to mitigate any disaster posed by natural hazards.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.207-213
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• 1999

In this study, the possibility of estimation of friction coefficient between tire and road surface using running car data are checked. To get necessary data, such as tire and car velocities and braking force, a test car is driven with certain magnitude of decelerations from pre-set initial velocities to stop . The data are used to estimate friction coefficient with property chosen parameters , e.g,, driving stiffness, pressure distribution functions, etc. Experimental results show that running data car be used with properly chosen parameters to estimate friction coefficient.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.410-413
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• 2008

We constructed the regional flood risk and damage magnitude using hazard and vulnerabilities which are climatic, hydrological, socio-economic, countermeasure, disaster probability components for DB construction on the GIS system. Also we developed the Excess Flood Vulnerability index estimation System(EFVS). By the construction of the System, we can perform the scientific flood management for the flood prevention and optional extreme flood defenses according to regional characteristics. In order to evaluate the performance of system, we applied EFVS to Anseong-chen in Korea, and the system's stabilization is appropriate to flood damage analysis.

• Journal of information and communication convergence engineering
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• v.16 no.1
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• pp.6-11
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• 2018

It is important to find the random estimation points in wireless sensor network. A link quality indicator (LQI) is part of a network management service that is suitable for a ZigBee network and can be used for localization. The current quality of the received signal is referred as LQI. It is a technique to demodulate the received signal by accumulating the magnitude of the error between ideal constellations and the received signal. This proposed model accepts any number of random estimation point in the network and calculated its nearest anchor centroid node pair. Coordinates of the LQI sphere are calculated from the pair and are added iteratively to the initially estimated point. With the help of the LQI and weighted centroid localization, the proposed system finds the position of target node more accurately than the existing system by solving the problems related to higher error in terms of the distance and the deployment of nodes.