• Journal of Electrochemical Science and Technology
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• v.6 no.4
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• pp.146-151
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• 2015

Here I report an electrochemical simulation work that compares voltammetric current and resistance of a complex electrochemical reaction over a potential scan. For this work, the finite element method is employed which are frequently used for voltammetry but rarely for impedance spectroscopy. Specifically, this method is used for simulation of a complex reaction where a heterogeneous faradaic reaction is followed by a homogeneous chemical reaction. By tracing the current and its polarization resistance, I learn that their relationship can be explained in terms of rate constants of charge transfer and chemical change. An unexpected observation is that even though the resistance is increased by the rate of the following chemical reaction, the current can be increased due to the potential shift of the resistance made by the proceeding faradaic reaction. This report envisions a possibility of the FEM-based resistance simulation to be applied to understand a complex electrochemical reaction. Until now, resistance simulations are mostly based on equivalent circuits or complete mathematical equations and have limitations to find proper models. However, this method is based on the first-principles, and is expected to be complementary to the other simulation methods.

• Journal of Power Electronics
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• v.13 no.5
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• pp.757-765
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• 2013

For conventional interleaved two-phase forward converters with a common output inductor, the maximum duty cycle is 0.5, which limits the voltage range and increases the difficulty of the transformer's optimization. A new two-phase hybrid forward converter with series-parallel auto-regulated transformer windings is presented in this paper. With interleaved control signals for the two phases, the secondary windings of the transformers can work in series when the duty cycle is larger than 0.5, and they can work in parallel when duty cycle is lower than 0.5. Therefore, the maximum duty cycle is extended and the turns ratio of the transformer can be optimized. Duty cycle dependent auto-regulated windings result in the steady states of the converter being different in different duty cycle ranges (D>0.5 and D<0.5). Fortunately, the steady state gains of the proposed hybrid converter are identical at different duty cycle ranges, which means a stepless shift between two states. A prototype is built to verify the theoretical analysis. A conventional control loop is compatible for the whole input voltage range and load range thanks to the stepless shifting between the different duty cycle ranges.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.92-100
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• 2006

In many common control charting situations, the statistic to be charted can be viewed as the output of a linear filter applied to the sequence of process measurement data. In recent work that has generalized this concept, the charted statistic is the output of a general linear filter in impulse response form, and the filter is designed by selecting its impulse response coefficients in order to optimize its average run length performance. In this work, we restrict attention to the class of all second-order linear filters applied to the residuals of a time series model of the process data. We present an algorithm for optimizing the design of the second-order filter that is more computationally efficient and robust than the algorithm for optimizing the general linear filter. We demonstrate that the optimal second-order filter performs almost as well as the optimal general linear filter in many situations. Both methods share a number of interesting characteristics and are tuned to detect any distinct features of the process mean shift, as it manifests itself in the residuals.

• The Journal of Korean Academic Society of Nursing Education
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• v.23 no.3
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• pp.252-267
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• 2017

Purpose: This study aimed to investigate clinical nurses' perception on nursing managerial competencies. Methods: This was a descriptive study. The data were collected from 198 nurse managers who had worked in six general hospitals using a self-reporting questionnaire. Data were analyzed by descriptive statistics, t-test, ANOVA, and Importance-Performance Analysis. Results: Only 32% of the participants had experienced nursing managerial competency training. The mean score for perceived performance of nursing managerial competency was lower than that for perceived importance. There were significant differences in perceived importance, performance, and importance-performance gaps among head, charge, and staff nurses. Importance-performance analysis showed that three of the 30 nursing managerial competencies require further development: staffing, human resources development and education, and nursing standard development competency. There were significant differences in importance-performance gaps according to age, career years in current hospital, work shift, position, nursing delivery system, and nursing managerial competency-education experience. Conclusion: A training program for developing and improving nursing managerial competencies which is focused on the gaps in importance and performance level is needed for clinical nurses. In addition, it should be considered to improve nursing work conditions such as nursing delivery system and formal appointment in order to increase the performance of nursing managerial competencies.

• Journal of Korean Academy of Nursing Administration
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• v.15 no.3
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• pp.305-313
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• 2009

Purpose: This study was done to identify the current status of burnout research on Korean nurses and to suggest the directions for future research. Method: Fifty two articles between 1998 and 2007 were selected using the key words such as "Nurse" and "Burnout" from the database (RISS4U et al.). Results: 77.9% of studies were master's theses unpublished in the nursing journals. All studies were cross-sectional and therefore did not allow casual inference. Hospital nurses were the most common subjects (21 studies). The most frequently used burnout measurement instrument was the Burnout Measure, while the Maslach Burnout Inventory was used in only 6 studies. 55.7% of studies reported the average burnout score as higher than the middle level. Among individual factors, variables significantly correlated to burnout were age, position, work experience, coping, and personality. Some of job factors including shift work, workloads, job stress, and organizational commitment were also significantly related to burnout. There was very little discussion about the influence of organizational factors analyzed by unit or institution level. Conclusion: In Korea, the next phase of nurse burnout research needs to consider the measurement tool selection for the international comparison and longitudinal design to find more specific causal relationships.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.2
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• pp.104-109
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• 2012

Cooperative education, a new paradigm of education, is a educational method of combining classroom-based education with practical work experience. To obtain appropriate learning experience during the work period, industrial mentors who provide beneficial advice and instruct students, are needed. Industrial mentors, basically, performs various roles in helping students to make the experiential learning efficiently, and the scope of their role is broad. In this paper, we classified the role of industrial mentors, proposed appropriate operating models and described the detail of their responsibilities.

• Safety and Health at Work
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• v.4 no.2
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• pp.87-94
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• 2013

Background: In times of continuous change and volatile markets, organizations are increasingly characterized by downsizing, work intensification, and resource rationalization. This has resulted in diversification, and the emergence of newrisks within the field of occupational health and safety, with an important impact. This paper focuses on one such type of risk in the modern workplace-psychosocial risks. The current study aimed to explore stakeholder perspectives, regarding the extent to which psychosocial risks are incorporated into strategic risk management practices, at both the business and policy level. Methods: Semi-structured interviews were conducted with 14 professionals, representing employer, expert, policy maker, and trade union stakeholder perspectives. Results: It was found that the majority of organizations do not sufficiently, if at all, understand and incorporate psychosocial risks into strategic decision making, whereby the key barrier related to practical difficulties of not knowing how to manage psychosocial risks adequately. Conclusion: The study found that there is a need to close the gap between policy and practice on a number of levels. Future recommendations comprise a policy framework and infrastructure underpinned by educational initiatives, partnerships, and networks to drive a shift in attitudes toward recognizing the duality of the concept of risk (including both potential negative and positive outcomes) and moving beyond simple regulatory compliance.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1309-1312
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• 2009

Surface potential and growth processes of hexadecanethiol (HDT) self-assembled monolayers (SAMs) on Au(111) surfaces were examined by Kelvin probe method and scanning tunneling microscopy. It was found that surface potential strongly depends on surface structure of HDT SAMs. The surface potential shift for the striped phase of HDT SAMs chemisorbed on Au(111) surface was +0.45 eV, which was nearly the same as that of the flat-lying hexadecane layer physisorbed on Au(111) surface. This result indicates that the interfacial dipole layer induced by adsorption of alkyl chains is a main contributor to the surface potential change. In the densely-packed HDT monolayer, further change of the surface potential was observed, suggesting that the dipole moment of the alkanethiol molecules is an origin of the surface potential change. These results indicate that the work function of a metal electrode can be modified by controlling the molecular orientation of an adsorbed molecule.

• Korean Journal of Occupational Health Nursing
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• v.8 no.2
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• pp.156-161
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• 1999

The EMG(Electromyography) analysis was used to identify the fact the degree of inclined step was selected as dependent variable and feet muscle fatigue was selected as a independent variable. In a final result from EMG test. the shift in median frequency (MF) with 20, 25, 30, 35 degree of inclined steps indicated that 30 degree step was identified as most effective for a decrease in feet muscle fatigue. In a department store, 80% of the workers are female standing sales workers. They work at standing on average 10 hours per day. They performed heavy duty jobs such as lifting, lowering. packing and carrying heavy materials. Furthermore, even though they have work shoes, they usually use various kind of high heels. Eventually, this situation develops low-back-pain (LBP) problems for female workers. In conclusion, it is recommended that a particular branch in a department store claimed this step can effectively to circulate blood and significantly decrease feet muscle fatigue in lower extremity.

• Korean Journal of Occupational Health Nursing
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• v.23 no.2
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• pp.89-96
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• 2014

Purpose: The purpose of this study is to discover the influence of the working conditions on women workers' occupational stress. Methods: Descriptive method is used to identify women's stress depending on their general working features and conditions by conducting a survey of them in women-dominated service industries. SPSS 18.0 program is used for data analysis and descriptive statistics is presented with standard deviation, frequency and percentage. ${\chi}^2$-test is used as an analysis tool. To figure out factors that influence their stress, logistic regression analysis is used for general features and working conditions as independent variables, and occupational stress as a dependent variable. Results: As a result, among the independent variables, employment status, weekly working hours, career, shiftwork, and work-family-balance are meaningful factors that influence their stress. Temporary workers' stress is 3.65 times higher (p<.001), and workers working over 48 hours a week have 1.97 times higher stress (p<.003). Workers with over 5 years' career are under 1.73 times higher stress (p<.046) and shift workers are under 3.51 times higher stress (p<.001). Work family balance results in 1.93 times higher stress (p<.009). Conclusion: It is necessary to seek how to prevent and manage women workers' stress considering features.