• Title/Summary/Keyword: Auxiliary variable

Search Result 115, Processing Time 0.03 seconds

THE CALIBRATED VARIANCE ESTIMATOR UNDER THE UNIT NONRESPONSE

  • Son, Chang-Kyoon;Hong, Ki-Hak;Lee, Gi-Sung
    • Journal of applied mathematics & informatics
    • /
    • v.8 no.3
    • /
    • pp.975-987
    • /
    • 2001
  • We treat the problem of variance estimation for the estimator of population total, which is derived from the calibration estimation procedure corresponding to the levels of auxiliary information under nonresponse situation. We develop the calibrated variance estimation procedure using the fact that the population total and variance as well as the sample total and variance of the auxiliary variable are known. We show that the proposed variance estimation procedure improves the $Lundst\ddot{o}rm$ and $S\ddot{a}rndal's$ (1999) procedure with respect to the variance and nonresponse bias reduction through the simulation study.

A Study for the Unit Nonresponse Calibration using Two-Phase Sampling Method

  • Yum, Joon Keun;Jung, Young Mee
    • Communications for Statistical Applications and Methods
    • /
    • v.9 no.2
    • /
    • pp.479-489
    • /
    • 2002
  • The case which applies two-phase sampling to stratification and nonresponse problem, it is a poweful and effective technique. In this paper we study the calibration estimator and its variance estimator for the population total using two-phase sampling method according to the of auxiliary information for population and sample having strong correlation with an interested variable in unit nonresponse situation. The auxiliary information that available both at first-phase and second-phase sampling can be used to improve weights by the calibration procedure. A weight which corresponds to the product of sampling weights and response probability is calculated at each phase of sampling.

Design of the High Efficiency Bidirectional Converter for DC Distributed Power System (직류 배전 시스템을 위한 고효율 양방향 컨버터의 설계)

  • Tran, Duc-Hung;Choi, Woojin
    • Proceedings of the KIPE Conference
    • /
    • 2016.11a
    • /
    • pp.5-6
    • /
    • 2016
  • This paper introduces a high efficiency bidirectional resonant converter using an additional LC auxiliary circuit for dcdistribution applications. The LC auxiliary circuit operates as a variable inductor and the additional LC circuit helps to increase the effective magnetizing inductance, thereby reducing the turn-off and primary circulating current. A 5 kW bidirectional converter for dc-distribution system is implemented to verify the validity of the proposed method. The experimental results show the high efficiency characteristics of the proposed converter over the wide range of load in both direction of power flow. The maximum efficiency of the proposed system was 98.1 % at 3 kW.

  • PDF

A Modified Horvitz-Thompson Estimator by Transformation of Variables (변수변환에 의한 수정 HORVITZ-THOMPSON 추정량)

  • 류제복
    • The Korean Journal of Applied Statistics
    • /
    • v.17 no.1
    • /
    • pp.27-34
    • /
    • 2004
  • The Horvitz-Thompson(H-T) estimator is less efficient than PPS estimators in some cases. We use the two-stage variable transformation in order to remove the drawbacks and increase the efficiency of H-T estimator. We transform the auxiliary variable to use the Midzuno-Sen sampling scheme at the first stage. And the next stage, we also transform the study variable to reduce the variance of H-T estimator using the inclusion probability obtained from the first transformation. We compare the efficiency between a suggested modified H-T estimator and PPS estimators.

Application of KED Method for Estimation of Spatial Distribution of Probability Rainfall (확률강우량의 공간분포 추정을 위한 KED 기법의 적용)

  • Seo, Young-Min;Yeo, Woon-Ki;Lee, Seung-Yoon;Jee, Hong-Kee
    • Journal of Korea Water Resources Association
    • /
    • v.43 no.8
    • /
    • pp.757-767
    • /
    • 2010
  • This study employs the KED method using the correlations between probability rainfall and topographical factors as single auxiliary variable for assessing the effectiveness of external variables to improve the reliability in the estimation of spatial distribution of probability rainfall. As a result, the KED method gives similar results compared with deterministic spatial interpolation methods and kriging methods in the estimation of rainfall spatial distribution and mean areal rainfall, and as a result of the cross-validations of KED and kriging methods, the KED method using terrain elevation as auxiliary variable gives the best results, which are not significantly different in comparisons with other methods.

Efficient Use of Auxiliary Information through the Stratified Sampling and Systematic Sampling Design (층화추출과 계통추출을 이용한 효율적인 보조정보 사용)

  • Kim, Gwan-Su;Park, Min-Gue
    • Survey Research
    • /
    • v.10 no.1
    • /
    • pp.155-168
    • /
    • 2009
  • As an efficient sampling design, stratified random sampling is often used when auxiliary information is available at the designing stage. Although one - per - stratum design is an efficient design that can be used when many auxiliary variables are available, it does not provide any unbiased variance estimator. With a two - per - stratum sample in which two elements are selected from each stratum, it is possible to obtain an unbiased variance estimator. However the loss of efficiency could be significant if any important stratification variable is missed. In this study, we investigated a sampling design that uses the all given auxiliary information and also permits an unbiased variance estimator suggested by Park and Fuller(2008). Through a simulation study, we compared several stratified random sampling and systematic sampling design. We also applied the proposed stratified sampling designs to 2007 youth panel data.

  • PDF

Calibration for Spatial Stratified Sampling Design (공간층화표본설계에 대한 보정)

  • Byun, Jong-Seok;Son, Chang-Kyoon;Kim, Jong-Min
    • Communications for Statistical Applications and Methods
    • /
    • v.17 no.1
    • /
    • pp.9-16
    • /
    • 2010
  • The sampling design for the spatial population studies needs a model assumption of a dependent relationship, where the interesting parameters can be the population mean, proportion and area. We know that the study of an interested spatial population, which is stratified by a geographical condition or shape, and the degree of distort of an estimation area is much useful. In light of this, if auxiliary information of the target variable such as wasted area contaminated by some material and the degree of distribution of animal or plants is available, then the spatial estimator might be improved through the calibration procedure. In this research, we propose the calibration procedure for the spatial stratified sampling in which we consider the one and two-dimensional auxiliary information.

Intelligent Control Algorithm for the Adjustment Process During Electronics Production (전자제품생산의 조정고정을 위한 지능형 제어알고리즘)

  • 장석호;구영모;고택범;우광방
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.4 no.4
    • /
    • pp.448-457
    • /
    • 1998
  • A neural network based control algorithm with fuzzy compensation is proposed for the automated adjustment in the production of electronic end-products. The process of adjustment is to tune the variable devices in order to examine the specified performances of the products ready prior to packing. Camcorder is considered as a target product. The required test and adjustment system is developed. The adjustment system consists of a NNC(neural network controller), a sub-NNC, and an auxiliary algorithm utilizing the fuzzy logic. The neural network is trained by means of errors between the outputs of the real system and the network, as well as on the errors between the changing rate of the outputs. Control algorithm is derived to speed up the learning dynamics and to avoid the local minima at higher energy level, and is able to converge to the global minimum at lower energy level. Many unexpected problems in the application of the real system are resolved by the auxiliary algorithms. As the adjustments of multiple items are related to each other, but the significant effect of performance by any specific item is not observed. The experimental result shows that the proposed method performs very effectively and are advantageous in simple architecture, extracting easily the training data without expertise, adapting to the unstable system that the input-output properties of each products are slightly different, with a wide application to other similar adjustment processes.

  • PDF

Evaluating the efficiency of treatment comparison in crossover design by allocating subjects based on ranked auxiliary variable

  • Huang, Yisong;Samawi, Hani M.;Vogel, Robert;Yin, Jingjing;Gato, Worlanyo Eric;Linder, Daniel F.
    • Communications for Statistical Applications and Methods
    • /
    • v.23 no.6
    • /
    • pp.543-553
    • /
    • 2016
  • The validity of statistical inference depends on proper randomization methods. However, even with proper randomization, we can have imbalanced with respect to important characteristics. In this paper, we introduce a method based on ranked auxiliary variables for treatment allocation in crossover designs using Latin squares models. We evaluate the improvement of the efficiency in treatment comparisons using the proposed method. Our simulation study reveals that our proposed method provides a more powerful test compared to simple randomization with the same sample size. The proposed method is illustrated by conducting an experiment to compare two different concentrations of titanium dioxide nanofiber (TDNF) on rats for the purpose of comparing weight gain.

A Diode Bridge-type ZVT Inverter for Induction Motor Drive Application (유도 전동기 구동용 다이오드 브릿지-타입 ZVT 인버터)

  • 이성룡;고성훈;권순신;송인석
    • Proceedings of the KIPE Conference
    • /
    • 1999.07a
    • /
    • pp.295-298
    • /
    • 1999
  • In this paper, the diode bridge-type ZVT(Zero-Voltage Transition) inverter is proposed. It consists of one auxiliary switch, three resonant inductors and six blocking diodes. So, the advantage of the proposed topology is the reduction of the auxiliary switch. The topology of the proposed ZVT inverter is analyzed with a description of the control conditions based on the load current. Therefore, this paper two control algorithms were discussed. A variable resonant pattern control algorithm by using load current feedback and a resonant period control algorithm by using resonant inductor current feedback is proposed in order to achieve the ZVT switching condition in full control range and the reducing current spike main switches cause by reverse recovery problem.

  • PDF