• Journal of Korean Academy of Nursing
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• v.14 no.2
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• pp.28-37
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• 1984

The purpose of this study is to propose the baseline data for developing the stress measurement tool for staff nurses working in the hospital. Two hundred and fifteen stan nurses in Seoul National University Hospital were participated during the period from Feb. 28 to Mar. 10, 1984. Though the pretest and literature review a questionnaire was constructed with 63 stressors which were experienced by the nurses in the hospital. Subjects were given instruction to rate 1∼6 likert type scale according to the level of stress experienced by each stressor described. Reliability of the tool was tested by Cronbach's Alpha, and the result was α=0.94871. Factor analysis was applied to organize 63 items together. As the result, 15 factors were obtained and these factors explained 66.3% of variance. The 15 factors were: 1) Work overload 2) Role conflict as a profession 3) Lack of professional knowledge and skill 4) Interpersonal problem 5) Conflict in nurse doctor relationship 6) Work conflict with doctors 7) Emotional burden due to the limitation of medicine 8) Poor treatment 9) Unsatisfactory relationship with supervisor 10) Low reward 11) Unsatisfactory relationship with subordinate 12) Poor physical environment of unit 13）Responsibility for extra affairs 14）Unfamiliar situation 15）Night duty.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.385-393
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• 2022

This study conducted a survey of social welfare facility workers in Mokpo, Jeollanam-do from May 21 to May 24, 2019 to empirically analyze the effect of job rotation on work efficiency and job satisfaction. Individual development of job rotaion (independent variable), job satisfaction (dependent variable), work efficiency (mediating variable), and work overload (moderating variable) were set as variables of the research model. For the questions of all variables, the Likert 5-point scale was used, the SPSS version 24.0 was used as an empirical analysis tool to verify the hypothesis, descriptive statistics and reliability analysis were performed, and the mediating effect and moderating effect were analyzed using SPSS PROCESS macro 4.0. The results of this study are as follows. First, it was analyzed that the individual development of job rotation did not significantly affect job satisfaction. Second, it was found that work efficiency fully mediated the relationship between individual development of job rotation and job satisfaction. Finally, it was found that the interaction term between work efficiency and job overload had a negative effect on job satisfaction and had a moderated mediating effect.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.5
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• pp.1176-1181
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• 1995

Microdrilling is one of the most difficult operations because of the poor chip discharge and the weakness of tool. This study is concerned about the development of a microdrilling monitoring system that is useful for minimizing the tool breakage and enhancing the machinability in the air spindle based microdrilling. The system is composed of a drilling state detection unit and an adaptive step-feed control unit that controls the micro-stepping motor driven spindle axis. Drilling states such as overload, tood breakage are recognized by the change of the air spindle speed which is measured via the reflective photo sensor. Based on the monitoring results, the adaptive step-feed control algorithm adjusts the step increment to keep the decrease of spindle speed within a specified range. The results of evaluation tests have shown that the developed system is very effective to prevent the breakage of microdrill and improves the productivity in comparison with the conventional microdrilling.

• Journal of Sensor Science and Technology
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• v.31 no.1
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• pp.57-63
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• 2022

This study describes a system that monitors the tool and cutting state of automatic beveling operation in real time. As a signal for cutting state monitoring, a motor current detected from the spindle drive system of the automatic beveling machine is used to monitor abnormal state. Because automatic beveling is processed using a face milling cutter, the cutting force mechanism is the same as the milling process. The predicted cutting torque is obtained using a cutting force model based on specific cutting resistance. Then, the predicted cutting torque is converted into the spindle motor current value, and cutting state stability is diagnosed by comparing it with the motor current value detected during beveling operation. The experimental results show that the spindle motor current can detect abnormal cutting state such as overload and tool wear during beveling operation, and can diagnose the cutting stability using the proposed equip-current line diagram.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.5
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• pp.98-107
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• 1995

The in-process detection of drill wear and breakage is one of the most importnat technical problems in unmaned machining system. In this paper, the monitoring system is developed to monitor abnormal drilling states such as drill breakage, drill wear and unstable cutting using motor current. Drill breakage is detected by level monitoring. Tool wear is classified by fuzzy pattern recognition. The key feature for classification of tool wear is the estimated flank wear which is calculated by the proposed flank wear model. The characteristic of the model is not sensitive to the variation of cutting conditions but is sensitive to drill wear state. Unstable cutting states due to the unsmooth chip disposal and the overload are monitored by the variance/mean ratio of spindle motor current. Variance/mean ratio also includes the information about the prediction of drill wear and drill breakage. The evaluation experiments have shown that the developed system works very well.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.3
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• pp.397-407
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• 1995

Use of a hypertext is growing as multimedia and hypermedia systems become popular. The major difference between hypertext-based and ordinary user interfaces is navigation. Typically, there are two major navigation problems in a hypertext compared to the ordinary user interface: "Disorientation" and "Cognitive Overload". To reduce or eliminate these problems of the hypertext system, a variety of aiding tools have been proposed. Among them, a local map is a good tool for helping users navigate through screens, especially for a large and complex system. This study examined three major design variables of a local map in a hypertext: breadth, depth, and functionality of a map. A human factors experiment was conducted to investigate the effects of these variables. Based upon the results of the experiment, design guidelines are suggested.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.120-126
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• 1997

This paper examines the crack growth behavior of 7075-T651 aluminum alloy under high-low block loading condition. The cantilever beam type specimen with a chevron notch is used in this study. The crack growth and closure are investgated by compliance method. The applied initial stress ratios are R=-0.5, R=0.0 and R=0.25 Crack length($\alpha$), effective stress intensity factor range(ΔKeff), ratio of effective stress intensity factor range(U) and crack growth rate(d$\alpha$/dN) etc. are inspected fracture mechanics estimate.

• Korean System Dynamics Review
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• v.4 no.2
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• pp.131-151
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• 2003

Traffic congestion stems from the widespread desires of people to purse certain goals that inevitably overload existing roads every day. he a transportation policy, congestion toll system has been implemented in Seoul, since 1996. The growing concerns on whether the system would achieve sustained results in the future motivated us to investigate the effectiveness of this policy. Developing and running the congestion toll simulation model, we find that this policy is not an effective policy in the long m. The paper indicates the power of system dynamics approach as a tool for evaluating complex policy like a congestion toll, and suggest that city transportation policy maker should approach the problem with systems thinking and analyze the effectiveness of policy on the basis of understanding the dynamic relationships among subsystems.

• Journal of Veterinary Science
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• v.22 no.5
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• pp.60.1-60.9
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• 2021

Background: Echocardiography is a primary tool used by veterinarians to evaluate heart diseases. In recent years, various studies have targeted standard echocardiographic values for different breeds. Reference data are currently lacking in Maltese dogs and it is important to fill this gap as this breed is predisposed to myxomatous mitral valve disease, which is a volume overload disease. Objectives: To establish the normal echocardiographic parameters for Maltese dogs. Methods: In total, 23 healthy Maltese dogs were involved in this study. Blood pressure measurements, thoracic radiography, and complete transthoracic echocardiography were performed. The effects of body weight, age and sex were evaluated, and the correlations between weight and linear and volumetric dimensions were calculated by regression analysis. Results: The mean vertebral heart size was 9.1 ± 0.4. Aside from the ejection fraction, fractional shortening, and the left atrial to aorta root ratio, all the other echocardiographic parameters were significantly correlated with weight. Conclusion: This study describes normal echocardiographic parameters that may be useful in the echocardiographic evaluation of Maltese dogs.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.15-27
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• 1997

Quasti-static cutting force variations in milling process are measured indirectly using spindle motor current. Quasi-static sensitivity of the spindle motor current is higher than that of the feed motor current. Magnitude of the spindle motor current is independent of cutting direction. The linear relationship between the cutting force and the spimdle motor RMS current at various spindle rotational speed is obtained. Frequency/ Voltage(F/V) converter voltage is measured to identify the spindle speed and to determine the cutting force at various spindle speeds. Overload on the tool during milling process can be detected using the proposed indirect cutting force measurement. Based on these measurements, cutting force is regulated at a constant level by feedrate control.