• Title/Summary/Keyword: ESTIMATION

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A Comparison of Estimation in an Unbalanced Linear Mixed Model (불균형 선형혼합모형에서 추정량)

  • 송석헌;정병철
    • The Korean Journal of Applied Statistics
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    • v.15 no.2
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    • pp.337-354
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    • 2002
  • This paper derives three estimation methods for the between group variance component for serially correlated random model. To compare their estimation capability, three designs having different degree of unbalancedness are considered. The so-called empirical quantile dispersion graphs(EQDGs) used to compare estimation methods as well as designs. The proposed conditional ANOVA estimation is robust for design unbalancedness, however, ML estimation is preferred to the conditional AOVA and REML estimation regardless of design unbalancedness and correlation coefficient.

A Bit of Factory Automation : Manufacturing Cost Estimation Using Group Technology (공장 자동화에 관한 소고 : 그룹 테크놀로지를 이용한 생산원가 추정)

  • Lee, Sung-Youl
    • Journal of Korean Institute of Industrial Engineers
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    • v.15 no.2
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    • pp.77-86
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    • 1989
  • A fully automated cost estimation system(FACES) has been developed. Since speed, accuracy, and consistency are essential factors in automating a cost estimation, the use of computers in cost estimation system(CES) has grown rapidly in the last few years. FACES is a micro computer based cost estimation system that employs a manufacturing knowledge base. A Group Technology(GT) based part classification and coding(C&C) scheme is used to automate the process planning aspects of cost estimation. Variant process planning methods are employed to generate workstation routings from form features of the part. The system has been tested for an assembly of six machined parts. Results indicate that the system could provide a substantial improvement in accuracy, productivity, and performance over the more traditional full dialog approach to cost estimation. It also provides a good foundation for a factory automation by using a common GT based database through design to production.

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Estimation of Change Point in Process State on CUSUM ($\bar{x}$, s) Control Chart

  • Takemoto, Yasuhiko;Arizono, Ikuo
    • Industrial Engineering and Management Systems
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    • v.8 no.3
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    • pp.139-147
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    • 2009
  • Control charts are used to distinguish between chance and assignable causes in the variability of quality characteristics. When a control chart signals that an assignable cause is present, process engineers must initiate a search for the assignable cause of the process disturbance. Identifying the time of a process change could lead to simplifying the search for the assignable cause and less process down time, as well as help to reduce the probability of incorrectly identifying the assignable cause. The change point estimation by likelihood theory and the built-in change point estimation in a control chart have been discussed until now. In this article, we discuss two kinds of process change point estimation when the CUSUM ($\bar{x}$, s) control chart for monitoring process mean and variance simultaneously is operated. Throughout some numerical experiments about the performance of the change point estimation, the change point estimation techniques in the CUSUM ($\bar{x}$, s) control chart are considered.

Comparison of Reliability Estimation Methods for One-shot Systems Using Accelerated Life Tests (가속수명시험을 이용한 원샷 시스템의 신뢰도 추정방법 비교)

  • Son, Young-Kap;Jang, Hyun-Jung
    • Journal of Korean Institute of Industrial Engineers
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    • v.36 no.4
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    • pp.212-218
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    • 2010
  • This paper shows accuracy comparison results of reliability estimation methods for one-shot systems with respect to sample sizes. To compare accuracy in reliability estimation methods, quantal-response data, characterizing one-shot systems, were simulated using failure times of LED obtained through the accelerated life test, and then the true reliability over time was evaluated using the failure times. The simulated quantal-response data were used to estimate the true reliability through applying reliability estimation methods in open literature. Accuracy of each reliability estimation method was compared in terms of both SSE (Sum of Squared Error) and MSE (Mean Squared Error), and then estimation trend for each method is found. Feasible bounds which true reliability would exist within were estimated through applying the found trends to quantal-response data set of a real weapon system.

Single Image Fog Removal based on JBDC and Pixel-based Transmission Estimation

  • Kim, Jongho
    • International journal of advanced smart convergence
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    • v.9 no.3
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    • pp.118-126
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    • 2020
  • In this paper, we present an effective single image fog removal by using the Joint Bright and Dark Channel (JBDC) and pixel-based transmission estimation to enhance the visibility of outdoor images susceptible to degradation due to weather and environmental conditions. The conventional methods include refinement process of coarse transmission with heavy computational complexity. The proposed transmission estimation reveals excellent edge-preserving performance and does not require the refinement process. We estimate the atmospheric light in pixel-based fashion, which can improve the transmission estimation performance and visual quality of the restored image. Moreover, we propose an adaptive transmission estimation to enhance the visual quality specifically in sky regions. Comprehensive experiments on various fog images show that the proposed method exhibits reduced computational complexity and excellent fog removal performance, compared with the existing methods; thus, it can be applied to various fields including real-time devices.

Nonlinear hierarchical motion estimation method based on decompositionof the functional domain (범함수 정의역 분할에 바탕을 둔 비선형 계층적 움직임 추정기법)

  • 심동규;박래홍
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.4
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    • pp.807-821
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    • 1996
  • In this paper, we proposed a nonlinear hierarchical mtion estimation method. Generally, the conventional hierarchical motion estimation methods have been proposed for fast convergence and detection of large motions. But they have a common drawback that large error in motion estimation is propapated across motion discontinuities. This artifiact is due to the constriaint of motion continuity and the linear interpolation of motion vectors between hierarchical levels. In this paper, we propose an effective hierarchical motion estimation mechod that is robust to motion discontinuities. The proposed algorithm is based on the decomposition of the functional domain for optimizing the intra-level motion estimation functional. Also, we propose an inter-level nonlinear motion estimation equation rather than using the conventional linearprojection scheme of motion field. computer simulations with several test sequences show tht the proposed algorithm performs better than several conventional methods.

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A Suggestion of Fuzzy Estimation Technique for Uncertainty Estimation of Linear Time Invariant System Based on Kalman Filter

  • Kim, Jong Hwa;Ha, Yun Su;Lim, Jae Kwon;Seo, Soo Kyung
    • Journal of Advanced Marine Engineering and Technology
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    • v.36 no.7
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    • pp.919-926
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    • 2012
  • In order to control a LTI(Linear Time Invariant) system subjected to system noise and measurement noise, first of all, it is necessary to estimate the state of system with reliability. Kalman filtering technique has been widely used to estimate the state of the stochastic LTI system with stationary noise characteristics because of its estimation ability versus algorithm simplicity. However, it often fails to estimate the state of the LTI system of which system parameter uncertainty exists partly and/or input uncertainty exists. In this paper, a new estimation technique based on Kalman filter is suggested for stochastic LTI system under parameter uncertainty and/or input uncertainty. A fuzzy estimation algorithm against uncertainties is introduced so as to compensate the state estimate filtered by Kalman filter. In order to verify the state estimation performance of the suggested technique, several simulations are accomplished.

A Study on the Desired Target Signal Estimation using MUSIC and LCMV Beamforming Algorithm in Wireless Coherent Channel

  • Lee, Kwan Hyeong
    • International journal of advanced smart convergence
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    • v.9 no.1
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    • pp.177-184
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    • 2020
  • In this paper, we studied to direction of arrival (DoA) estimation to use DoA and optimum weight algorithms in coherent interference channels. The DoA algorithm have been considerable attention in signal processing with coherent signals and a limited number of snapshots in a noise and an interference environment. This paper is a proposed method for the desired signal estimation using MUSIC algorithm and adaptive beamforming to compare classical subspace techniques. Also, the proposed method is combined the updated weight value with LCMV beamforming algorithm in adaptive antenna array system for direction of arrival estimation of desired signal. The proposed algorithm can be used with combination to MUSIC algorithm, linearly constrained minimum variance beamforming (LCMV) and the weight value method to accurately desired signal estimation. Through simulation, we compare the proposed method with classical direction of in order to desired signals estimation. We show that the propose method has achieved good resolution performance better that classical direction arrival estimation algorithm. The simulation results show the effectiveness of the proposed method.

Comparative Study of First-in-Human Dose Estimation Approaches using Pharmacometrics (약물계량학을 이용한 초기임상1상 시험 용량 예측 방법에 대한 비교연구)

  • Baek, In-hwan
    • Korean Journal of Clinical Pharmacy
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    • v.26 no.2
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    • pp.150-162
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    • 2016
  • Objective: First-in-human dose estimation is an essential approach for successful clinical trials for drug development. In this study, we systematically compared first-in-human dose and human pharmacokinetic parameter estimation approaches. Methods: First-in-human dose estimation approaches divided into similar drug comparison approaches, regulatory guidance based approaches, and pharmacokinetic based approaches. Human clearance, volume of distribution and bioavailability were classified for human pharmacokinetic parameter estimation approaches. Results: Similar drug comparison approaches is simple and appropriate me-too drug. Regulatory guidance based approaches is recommended from US Food and Drug Administration (FDA) and European Medicines Agency (EMA) regarding no-observed-adverse-effect level (NOAEL) or minimum anticipated biological effect level (MABEL). Pharmacokinetic based approaches are 8 approaches for human clearance estimation, 5 approaches for human volume of distribution, and 4 approaches for human bioavailability. Conclusion: This study introduced and compared all methods for first-in-human dose estimation. It would be useful practically to estimate first-in-human dose for drug development.

Range and Velocity Estimation of the Object using a Moving Camera (움직이는 카메라를 이용한 목표물의 거리 및 속도 추정)

  • Byun, Sang-Hoon;Chwa, Dongkyoung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.12
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    • pp.1737-1743
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    • 2013
  • This paper proposes the range and velocity of the object estimation method using a moving camera. Structure and motion (SaM) estimation is to estimate the Euclidean geometry of the object as well as the relative motion between the camera and object. Unlike the previous works, the proposed estimation method can relax the camera and object motion constraints. To this end, we arrange the dynamics of moving camera-moving object relative motion model in an appropriate form such that the nonlinear observer can be employed for the SaM estimation. Through both simulations and experiments we have confirmed the validity of the proposed estimation algorithm.