• Journal of Korean Academy of Nursing
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• v.47 no.5
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• pp.700-711
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• 2017

Purpose: This study aimed to test a proposed structural equation model in which bullying experience, conflict management styles and psychological empowerment predict psychological well-being among Chinese nursing students in clinical placement. Methods: Three hundred and sixty-six nursing students recruited from five hospitals in J city and Y city were assessed with self-report questionnaires on bullying experience, conflict management styles, psychological empowerment and psychological well-being including depression, self-esteem, and academic major satisfaction. Data were analyzed using SPSS version 20.0 and AMOS version 22.0. Results: The evaluation parameters included the comparative fit index at .90, the goodness of fit index at .93, the root mean square error of approximation at .07, and ${\chi}^2/df$ ratio at 2.66, indicating that the proposed structural equation model provided a good fit to the data. Experience of being bullied during clinical placement, conflict management styles and psychological empowerment explained 93.0% of the variance and had significant effects on psychological well-being, with conflict management styles and psychological empowerment mediating the association between bullying and psychological well-being. Conclusion: The findings indicated that mediation by conflict management styles and psychological empowerment alleviated the negative influence of bullying on psychological well-being. To limit bullying and its negative effects, development of effective guidelines to deal with bullying will be a critical tool for both Chinese nursing students and their instructors. Further research should incorporate conflict management styles and psychological empowerment into the specific intervention strategies for handling bullying behaviors among nursing students and staff nurses and promoting nursing students' psychological well-being.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.134-140
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• 1998

The authors have shown that the performance of discrete-time observer-based monitoring systems can be represented by the performance index k$_2$(P) (condition number of the eigensystem P of the observer matrix in terms of L$_2$ norm). The observers with the minimized performance index can be defined as robust observers in the sense that the observer performance can be guaranteed in harsh environments. In this paper, based on the performance index, a design methodology for the robust discrete-time observer is developed. Similar to the continuous-time case, the methodology determines the structure and eigenvalues of the observer matrix simultaneously. A complete design procedure is given for single-output case and is illustrated with a spindle-driver example. The simulation results demonstrate the improved performance compared with a traditional pole-placement observer technique.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.6
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• pp.555-562
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• 2013

This paper presents the optimal array of optical mice for the accurate velocity estimation of a mobile robot. It is assumed that there can be some restriction on the installation of two or more optical mice at the bottom of a mobile robot. First, the velocity kinematics of a mobile robot with an array of optical mice is derived, which maps the velocity of a mobile robot to the velocities of optical mice. Second, taking into account the consistency in physical units, the uncertainty ellipsoid is obtained to represent the error characteristics of the mobile robot velocity estimation owing to noisy optical mouse measurements. Third, a simple but effective performance index is defined as the inverse of the volume of the uncertainty ellipsoid, which can be used for the optimization of the optimal optical mouse placement. Fourth, simulation results for the optimal placement of three optical mice within a given elliptical region are given.

• Journal of the korean academy of Pediatric Dentistry
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• v.4 no.1
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• pp.28-34
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• 1977

The present study was undertaken to evaluate gingivitis and oral hygiene status of the crowned teeth comparing to controlled teeth by use of P. M. A. Index and Oral Hygiene. Index in children from $3\frac{1}{2}$ to $7\frac{1}{2}$ years old. The results were as followings. 1. In P. M. A. Index, satisfactory crowned teeth (1.53) showed statistically significant increment compare to the controlled teeth (0.68) (P<0.01). 2. In P. M. A. Index, unsatisfactory crowned teeth (2.22) showed statistically significant increment compare to the controlled teeth (0.70) (P<0 01). 3. In Oral Hygiene Index, satisfactory crowned teeth (1.49) showed statistically nonsignificant increment compare to the controlled teeth (1.27). 4. In Oral Hygiene Index, unsatisfactory crowned teeth (1.62) showed statistically nonsignicant increment compare to the controlled (1.39) 5. The severity of gingivitis following Oral Hygiene Index showed higher in crowed teeth than the controlled teeth. 6. The severity of giginvitis showed the highest in the unsatisfactory crowned teeth, the next was the satisfactory crowned teeth, and the controlled teeth showed the lowest.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.492-498
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• 2009

The placement of the UPFC is the major concern to ensure the full potential of utilization in the transmission network. Voltage stability enhancement with the optimal placement of UPFC using stability index such as modal analysis, Voltage Phasor method is made and the loss minimization including UPFC is formulated as an optimization problem. This paper proposes particle swarm optimization for the exact real power loss minimization including UPFC. The implementation of loss minimization for the optimal location of UPFC was tested with IEEE-14 and IEEE-57 bus system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.12-16
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• 2002

Dynamic characteristics of smart laminated composite plates with passive constrained layer damping have been investigated to design structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, multi-layer laminated plates. The damping ratio and modal damping of the first bending and torsional modes are calculated by means of iterative complex eigensolution method. The structural damping index(SDI) is introduced to determine the optimum placement of viscoelastic patch. This paper addresses a design strategy of laminated composite plate under vibrations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.684-688
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• 1998

Optimization of the collocated piezoceramic sensor/actuator placement is investigated numerically and verified experimentally for vibration control of laminated composite plates. The finite element method is used for the analysis of dynamic characteristics of the laminated composite plates with the piezoceramic sensor/actuator. The structural damping index(SDI) is defined from the modal damping. It is chosen as the objective function for optimization. Weights for each vibrational mode are taken into account in the SDI calculation. The gradient method is used for the optimization. Optimum location of the piezoceramic sensor/actuator is determined by maximizing tie SDI. Numerical simulation and experimental results show that the optimum location of the piezoceramic sensor/actuator is dependent upon the outer layer fiber orientations of the plate, and location and size of the piezoceramic sensor/actuator.

• Journal of Mechanical Science and Technology
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• v.15 no.8
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• pp.1119-1131
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• 2001

In this paper we formulate an optimization based approach to determining the maximally inscribed rectangle in a robots workspace. The size and location of the maximally inscribed rectangle is an effective index for evaluating the size and quality of a robots workspace. Such information is useful for, e. g., optimal worktable placement, and the placement of cooperating robots. For general robot workspaces we show how the problem can be formulated as a constrained nonlinear optimization problem possessing a special structure, to which standard numerical algorithms can be applied. Key to the rapid convergence of these algorithms is the choice of a starting point; in this paper we develop an efficient computational geometric algorithm for rapidly obtaining an approximate solution suitable as an initial starting point. We also develop an improved version of the algorithm of Haug et al. for calculating a robots workspace boundary.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1271-1280
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• 2000

A sensor placement technique to identify structural parameter was developed. Experimental results must be acquired to identify unknown dynamic characteristics of a targeting structure for the comparison between analytical model and real structure. If the experimental environment was not equipped itself properly, it can be happened that some valuable information are distorted or ill-condition can be occurred. In this work the index to determine exciting points was derived from the criterion of maximizing parameter sensitivity matrix and that to choose measurement points was from that of preserving the invariant of sensitivity matrix. This idea was applied to a compressor hull structure to verify its performance. The result shows that the selection of measurement and excitation points using suggested criteria improve the ill-conditioning problem of inverse type problems such , as model updating.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2060-2066
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• 2002

The closed-loop state and input observer is a pole-placement type observer and estimates unknown state and input variables simultaneously. Pole-placement type observers may have poor transient performance with respect to ill-conditioning factors such as unknown initial estimates, round-off error, etc. For the robust transient performance, the effects of these ill-conditioning factors must be minimized in designing observers. In this paper, the transient performance of the closed-loop state and input observer is investigated quantitatively by considering the error bounds due to ill-conditioning factors. The performance indices are selected from these error bounds and are related to the observer robustness with respect to the ill -conditioning factors. The closed-loop state and input observer with small performance indices is considered as a well-conditioned observer from the transient perspective.