• Communications for Statistical Applications and Methods
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• v.5 no.2
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• pp.339-351
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• 1998

Designs for discriminating between two linear regression models are studied under $\Lambda$-type optimalities maximizing the measure for the lack of fit for the designs with fixed model inadequacy. The problem of selecting an appropriate $\Lambda$-type optimalities is shown to be closely related to the estimation method. $\Lambda$-type optimalities for the least squares and minimum bias estimation methods are considered. The minimum bias designs are suggested for the designs invariant with respect to the two estimation methods. First order minimum bias designs optimal under $\Lambda$-type optimalities are then derived. Finally for the case where the lack of fit test is significant, an approach to the construction of a second order design accommodating the optimal first order minimum bias design is illustrated.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1227-1234
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• 2015

Traditional criteria for optimum experimental designs depend on the specifications of the model; however, there will be a dilemma when we do not have perfect knowledge about the model. Box and Draper (1959) suggested one direction to minimize bias that may occur in this situation. We will demonstrate some examples with exact solutions that provide a no-bias design for polynomial regression. The most interesting finding is that a design that requires less bias should allocate design points away from the border of the design space.

• The Korean Journal of Applied Statistics
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• v.15 no.2
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• pp.395-403
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• 2002

In the third phase of the response surface methods, the first-order model is assumed and the curvature of the response surface is checked with a fractional factorial design augmented by centre runs. We further assume that a true model is a quadratic polynomial. To choose an optimal design, Box and Draper(1959) suggested the use of an average mean squared error (AMSE), an average of MSE of y(x) over the region of interest R. The AMSE can be partitioned into the average prediction variance (APV) and average squared bias (ASB). Since AMSE is a function of design moments, region moments and a standardized vector of parameters, it is not possible to select the design that minimizes AMSE. As a practical alternative, Box and Draper(1959) proposed minimum bias design which minimize ASB and showed that factorial design points are shrunk toward the origin for a minimum bias design. In this paper we propose a robust AMSE design which maximizes the minimum efficiency of the design with respect to a standardized vector of parameters.

• Journal of the Korean Statistical Society
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• v.20 no.2
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• pp.147-155
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• 1991

This paper treats a robust design criterion which minimizes the effects of outliers and model inadequacy, and investigates robust designs for some response surface designs. In order to develop a robust design criterion and robust design, the integrated mean squared error of *(equation omitted) over a region is utilized, where *(equation omitted). is the estimated response by the minimum bias estimation proposed by carson, Manson and Hader (1969) . According to the number of aberrant observations and their positions, the proposed criterion and designs are studied. Also further development of the proposed criterion is treated when outliers can occur in any position of a design.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.22-28
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• 1998

A new type of FET source mixer with a single bias voltage has been presented. It is designed to operate at Vds=0 [V] with only one positive supply voltage, which makes mixer circuits simple. The proposed mixer has shown improved stability and less sensitivity to both bias and LO power compared with conventional active mixers. It also shows lower conversion loss than that of diode mixers. The minimum conversion loss measured at RF frequency of 5.6㎓ is 0.6㏈ for a LO frequency of 5.8㎓.

• Journal of the Korean Statistical Society
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• v.9 no.2
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• pp.145-172
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• 1980

Draper and Lawrence (1965a) have given mixture designs for three factors when all the mixture components can vary on the entire factor space so that the region of interest is an equilateral triangle in two dimensions. In this paper their work is extended to the cases when the region of interest is an echelon, parallelogram, pentagon or hexagon, because of the restirctions imposed on some or all of the mixture components. The principles used in the choice of appropriate designs are those originally introduced by Box and Draper(1959). It is assumed that a response surface equation of first order is fitted, but there is a possibility of bias error due to presence of second order terms in the true model. Minimum bias designs for several cases of restricted regions of interest are illustrated.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.123-130
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• 2003

We define a broad class of rotation designs whose monthly sample is balanced in interview time, level of recall, and rotation group, and whose rotation scheme is time-invariant. The necessary and sufficient conditions are obtained for such designs. Using these conditions, we derive a minimum variance unbiased generalized composite estimator (MVUGCE). To examine the existence of time-in-sample bias and recall bias, we also propose unbiased estimators and their variances. Numerical examples investigate the impacts of design gap, non-sampling error sources, and two types of correlations on the variance of MVUGCE.

• Journal of IKEEE
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• v.20 no.3
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• pp.251-259
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• 2016

This paper describes that how to enhance the robustness of semiconductor TRM(Transmitter and Receiver Module) through the bias sequencing and tuning the switching time. Previous circuit designs focused on improving the MDS(Minimum Detection Signal) performance. Because TRM has critical problem which transmission output signal leak into receiver by it's compact design. Under this condition, TRM was frequently broken down within the MTBF(Mean Time Between Failure). This study proposes the bias sequencing and tuning the switching time to improve above problem. At first, we collected major failure symptom and infer it's cause. Second, we demonstrated it's effect by derive the improvement method and apply it to our system. And finally we can convinced that the proposed method clear the frequent failure problem with its lack of isolation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.7
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• pp.875-880
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• 2016

A new hybrid permanent magnet biased magnetic levitation actuator (maglev) is developed. This new maglev actuator is composed of two C-core electromagnetic cores separated with two permanent magnets. Compared to the conventional hybrid maglev actuators, the new actuator has unique flux paths such that bias flux paths are separated with control flux paths. The control flux paths have minimum reluctances only developed by air gaps, so the currents to produce control fluxes can be minimized. The gravity load can be compensated with the permanent magnet bias fluxes developed at off-centered air gap positions while external disturbances are controlled with control fluxes by currents. The consumed power to operate this levitation system can be minimized. 1-D magnetic circuit model is developed for this model such that the flux densities and magnetic forces are extensively analyzed. 3-D finite element model is also developed to analyze the performances of the maglev actuator.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.1
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• pp.29-37
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• 2019

A new permanent magnet biased hybrid maglev actuator is developed. Compared to the classical hybrid maglev actuators, the new maglev has unique flux paths such that bias fluxes are separated with control flux paths. The control flux paths have minimum reluctances only developed by air gaps, so the currents to produce control fluxes can be minimized. The consumed power to operate this maglev system can also be minimized. The gravity load can be compensated with the static magnetic forces developed by the permanent magnet bias fluxes while external disturbances are controlled with the bidirectional AC magnetic forces developed by control fluxes by currents. 1-D circuit model is developed for this model such that the flux densities and magnetic forces are extensively analyzed. 3-D finite element model is also developed to analyze the performances of the maglev actuator.