• Korean Journal of Social Welfare
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• v.57 no.3
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• pp.133-164
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• 2005

This study examined the effects of children's perceived stress of economic strain, resulting family conflict, and stress coping strategies on their adjustment. Dimensions of children's adjustment studied in this research were problem behaviors (aggression, delinquency, withdrawal and anxiety depression) and school adjustment. Interaction effects between children's stress variables and coping strategies on the adjustment were also explored. 1,115 fifth to eighth graders from Chungbuk regions participated in self-administered structured questionnaires. Data were processed with SPSS PC 10.0 statistical package. Results were: First, the level of children's problem behaviors and school adjustment indicated differences according to their academic achievement, gender, and their age. Middle schoolers with rather low grade average reported higher level of aggression, delinquency, withdrawal and that of depression/anxiety. Boys tended to be more prone to external problems while girls to internal problems. Second, stresses originated from children's perceived economic strain and family conflicts showed consistent meaningful explanatory power on adjustment. Boys' adjustment was influenced by stress from economic strain and family conflict while girls by family conflict and academic achievements. The support seeking coping strategy among others was the most popularly employed coping strategy of children followed by aggressive coping strategy. In boys' cases, interaction effects of stress and coping strategies were significant in all of the adjustment variables, the more frequent the use of support seeking coping strategies, the lower the problem behavior, while interaction effect of family conflict stress and support seeking coping strategies played the opposite significant role in girls' cases. Further research efforts are required. Research results suggest; when developing a program facilitating children's adjustment, training on stress coping strategies should be considered as a potent new arena of interest.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2150-2161
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• 2016

Mechanical and electrical parameter uncertainties cause dynamic and static estimation errors of the rotor speed and position, resulting in performance deterioration of sensorless control systems. This paper applies an extended nonlinear observer to interior permanent magnet synchronous motors (IPMSM) for the simultaneous estimation of the rotor speed and position. Two compensation methods are proposed to improve the observer performance against parameter uncertainties: an on-line rotational inertia adjustment approach that employs the gradient descent algorithm to suppress dynamic estimation errors, and an equivalent flux error compensation approach to eliminate static estimation errors caused by inaccurate electrical parameters. The effectiveness of the proposed control strategy is demonstrated by experimental tests.

• Journal of Power Electronics
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• v.14 no.3
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• pp.541-548
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• 2014

This paper presents a simple lead angle adjustment method for brushless DC motors. The proposed method is based on the motor current dynamics analysis during the current commutation interval. With the proposed scheme, the phase current and phase back-EMF voltage are in phase and the BLDC motor and drive system have a high efficiency induced by the reduced copper and conduction losses. Experimental results are shown to validate the proposed method.

• Journal of Power System Engineering
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• v.6 no.1
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• pp.82-87
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• 2002

Not only ferrous but also non-ferrous materials such as aluminum, brass, plastic and woods need cutting operation in recent manufacturing industry. Over the past few years a considerable number of studies have been made on non-ferrous metal cutting. But more study is required to meet various engineering needs. The purpose of this paper is to preform an experiment on the influence of feed-rate adjustment and side rake angle in turning operations from non-ferrous metals. As a result, the surface roughness was reduced when a side-rake angle increases and feed-rate decreases in the case of the plastic, brass, aluminum, and paulownia. Therefore, this papers develop a new type bite that be used to adjust side-rake angle.

• Communications for Statistical Applications and Methods
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• v.25 no.6
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• pp.577-590
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• 2018

Employing the covariance adjustment technique, we show that in the system of two seemingly unrelated multivariate regressions the estimator of regression coefficients can be expressed as a matrix power series, and conclude that the matrix series only has a unique simpler form. In the case that the covariance matrix of the system is unknown, we define a two-stage estimator for the regression coefficients which is shown to be unique and unbiased. Numerical simulations are also presented to illustrate its superiority over the ordinary least square estimator. Also, as an example we apply our results to the seemingly unrelated growth curve models.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.1
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• pp.18-23
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• 2006

Cutting by a high speed laser cutting machine is one of most effective technologies to improve productivity. This paper has presented the cutting characteristics and optimal cutting conditions in a high speed feeding type laser cutting machine by using Tacuchi method in the design of experiment. An L9(34) orthogonal array is adopted to study the effect of adjustment parameters. The adjustment parameters consist of cutting speed, laser power, laser output duty and assistant gas pressure. The surface roughness of sheet metal is regarded as a quality feature. Analysis of variance is performed in order to evaluate the effect of adjustment parameters on the quality feature of laser cutting process.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.281-284
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• 2002

This paper describes the initial angle adjustment method on Hall Sensorless Linear Permanent Magnet Synchronous Motor The implementation of the controller is designed on the DSP TMS320C32 board. PMLSM is operated by using 4-point absolute positions profile with each velocity, acceleration and deceleration. To achieve Hall Sensorless characteristics, Moving Coil Type PMLSM is used and initial angle adjustment algorithm is adapted.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.26-33
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• 1994

Much time and labor has been conventionally paid for fine adjustment of circuit elements by experience to improve the characteristics of Tap-off for CATV systems. To solve the problem, in this paper, the relations between the even- and odd-mode impedance. Z$_{oe}$ and Z$_{oo}$ of symmetrical 4-port coupled-line directional coupler and power dividing characteristics of Tap-off for CATV system have been derived. After the coupling, the reflectivity and the isolation are represented by Z$_{oe}$ and Z$_{oo}$ only, the fine adjustment of all S-parameters can be performed by controling the elements of Z$_{oe}$ and Z$_{oo}$ only. Furthermore, the validity of the new fine adjustment method proposed here has been confirmed by experiments.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.6
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• pp.77-83
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• 2004

Cutting by a high speed laser cutting machine is one of most effective technologies to improve productivity. This paper has studied to obtain the cutting characteristics and optimal cutting conditions in a high speed feeding type laser cutting machine by Tacuchi method in design of experiments. A Lf(34) orthogonal array is adopted to study the effect of adjustment parameter. The adjustment parameters consist of cutting speed, laser power, laser output duty and assistant gas pressure. And the quality feature is selected as surface roughness of sheet metal. Variance analysis is performed in order to evaluate the effect of adjustment parameters on the quality feature of laser cutting process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.561-566
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• 2021

The optimum kernel size for error-distribution estimation with given error samples cannot be used in the weight adjustment of minimum Euclidean distance between error distributions (MED) algorithms. In this paper, a new adaptive kernel estimation method for convergence enhancement of MED algorithms is proposed. The proposed method uses the average rate of change in error power with respect to a small interval of the kernel width for weight adjustment of the MED learning algorithm. The proposed kernel adjustment method is applied to experiments in communication channel compensation, and performance improvement is demonstrated. Unlike the conventional method yielding a very small kernel calculated through optimum estimation of error distribution, the proposed method converges to an appropriate kernel size for weight adjustment of the MED algorithm. The experimental results confirm that the proposed kernel estimation method for MED can be considered a method that can solve the sensitivity problem from choosing an appropriate kernel size for the MED algorithm.