• Communications for Statistical Applications and Methods
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• 제16권5호
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• pp.821-840
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• 2009

This article addresses the problem of estimating a family of general population parameter ${\theta}_{({\alpha},{\beta})}$ using auxiliary information in the presence of measurement errors. The general results are then applied to estimate the coefficient of variation $C_Y$ of the study variable Y using the knowledge of the error variance ${\sigma}^2{_U}$ associated with the study variable Y, Based on large sample approximation, the optimal conditions are obtained and the situations are identified under which the proposed class of estimators would be better than conventional estimator. Application of the main result to bivariate normal population is illustrated.

• Geomechanics and Engineering
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• 제16권2호
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• pp.159-168
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• 2018

In this study, a real-time grouting management system based on the clogging theory was established to manage injection procedure in real time. This system is capable of estimating hydraulic permeability with the passage of time as the grout permeates through the ground, and therefore, capable of estimating real time injection distance and flow rate. By adopting the Controlled Injection Pressure (CoIP) model, it was feasible to predict the grout permeation status with the elapse of time by consecutively updating the hydraulic gradient and flow rate estimated from a clogging-induced alteration of pore volume. Moreover, a method to estimate the volume of the fractured gap according to the reduction in injection pressure was proposed. The validity of the proposed system was successfully established by comparing the estimated values with the measured field data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.60-65
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• 2003

In this study, for estimating responses of a controlled structure and determining the maximum control force of velocity-dependent damping devices, three estimation models such as Fourier envelope convex model, probability model, and Newmark design spectrum are used. For this purpose, a procedure proposed by Gupta (1990) for estimating spectral velocity using pseudo-spectral velocity which is given by the estimation models is used and modified to consider the effects of increased damping ratio by the damping device. Time history results indicate that Newmark design spectrum gives the best estimation of maximum control force for over all period structures.

• 물과 미래
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• 제12권2호
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• pp.56-62
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• 1979

강우자료로부터 설계 홍수량을 추정하는 많은 방법들은 설계강우량의 지속기간 결정에 매우 복잡한 시행 착오법을 사용하고 있으나, 본 연구에서는 순간단위유량도 이론을 적용한 해석적 방법에 의하여 근사 지속기간을 결정하는 방법을 이론적으로 전개하였다. 이렇게 유도된 방법을 무심천 대표유역에 적용하여 교점유량비곡선(hydrograph curve)과 재현기간별로 설계강우곡선(rainfall curve)을 계산하고, 그 결과를 동일 좌표상에 그려 그 교점이 표시하는 유효우량 지속기간을 결정하였다.

• 산업공학
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• 제10권3호
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• pp.125-132
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• 1997

We proposed a 2-step neural network approach for estimating machining parameters of electric discharge wire cut. The first step net, which is described as a backward neuro-estimation, is designed for estimating coarse cutting parameters while the second phase net, as a polishing forward neuro-estimation, is utilized for determining fine parameters. Sequential estimation procedure, based on backward and forward net, is performed using the net's approximation capability which is M to 1 and 1 to M mapping property. Experimental results an given to evaluate the accuracy of the proposed 2-step neuro-estimation.

• 한국국방경영분석학회지
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• 제31권2호
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• pp.45-59
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• 2005

As more advanced and complicated equipments are introduced, effective operation and maintenance, along with acquisition of the equipments, commands more significance lately. In order to perform effective depot maintenance, the Republic of Korea Army is continually developing the concept, cycle and method for operating the depot maintenance. Not only the high-cost testing and maintenance equipments but the highly developed maintenance technologies are required for the depot maintenance of the latest weapon system. In order to have the depot maintenance capability, this paper provides the standard and procedure for estimating the development cost of the depot maintenance elements to be utilized in the depot maintenance elements development project.

• Journal of Electrical Engineering and Technology
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• 제5권1호
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• pp.28-35
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• 2010

This paper presents new Adaptive Linear Combination Structure (ADALINE) for tracking/estimating voltage-current phasor and frequency of power system. To estimate the phasors and frequency from sampled data, the algorithm assumes that orthogonal coefficients and speed of angular frequency of power system are unknown parameters. With adequate sampled data, the estimation problem can be considered as a linear weighted least squares (LMS) problem. In addition to determining the phasors (orthogonal coefficients), the procedure estimates the power system frequency. The main algorithm is verified through a computer simulation and data from field. The proposed algorithm is tested with transient and dynamic behaviors during power swing, a step change of frequency upon islanding of small generators and disconnection of load. The algorithm shows a very high accuracy, robustness, fast response time and adaptive performance over a wide range of frequency, from 10 to 2000 Hz.

• 한국소프트웨어감정평가학회 논문지
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• 제16권1호
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• pp.21-26
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• 2020

The completeness appraisal of software is performed in various forms, such as assessing the completion level in the development process, calculating the defect rate, estimating the development cost, and calculating the redevelopment cost. Along with this, the problem that is often dealt with is estimation of the development time. Even in a dispute over completeness due to delays in software development, issues of calculating an appropriate development time required to develop a delivery software or a development time required for change requests are often included in the appraisal request. In this paper, we introduce the procedure and method for estimating the appropriate project time of software development so that the appraiser can be applied to the appraisal work for determining the completeness. The method is based on the manual for calculating the appropriate project period of software development project.

• Journal of Preventive Medicine and Public Health
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• 제55권2호
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• pp.116-124
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• 2022

Epidemiological studies typically examine the causal effect of exposure on a health outcome. Standardization is one of the most straightforward methods for estimating causal estimands. However, compared to inverse probability weighting, there is a lack of user-centric explanations for implementing standardization to estimate causal estimands. This paper explains the standardization method using basic R functions only and how it is linked to the R package stdReg, which can be used to implement the same procedure. We provide a step-by-step tutorial for estimating causal risk differences, causal risk ratios, and causal odds ratios based on standardization. We also discuss how to carry out subgroup analysis in detail.

• 산업경영시스템학회지
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• 제37권1호
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• pp.115-119
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• 2014

When the number of items of same type of industrial property is quite large, calculating depreciation for a group of such item may be more efficient than depreciating each item separately. Also, predicting the service life of a specific individual unit is very difficult to do with any degree of accuracy. Estimating the probable average service life (PASL) of many units (or dollars) is not an easy task; however, an average life of many units can probably be predicted with a much higher degree of accuracy than the life of some particular unit. Using the average of many units allows for some units having relatively short lives and some units having relatively long lives without specifying whether a particular unit will have a short or a long life. If the life of each vintage in an account are not estimated, then the broad group procedure can be used. The broad group procedure depreciates the several vintage in an account as a single group. The PASL for this procedure is the estimate of the average of lives of the individual dollars in the group. If the estimated PASL's of the vintages are not the same, then a weighted average PASL would have to be calculated for each calendar year. In this paper, we illustrate the calculations of accrual rates and the annual depreciation charge for each of the calendar years by the broad group depreciation procedure.