• Journal of Power Electronics
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• v.14 no.6
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• pp.1130-1138
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• 2014

This study analyzes a ladder multilevel converter (double ladder topology) with the use of a new averaging modeling technique. This technique introduces an analytical method to compute for the switching losses and is used to conduct an in-depth analysis of the influence of the switching frequency and parasitic resistance of components on converter efficiency. The obtained results enable the selection of switches and switching frequency to minimize losses. Moreover, simulation results and experimental measurements validate the analytical calculations.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.5
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• pp.88-94
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• 1994

Inverse Chebyshev function can realize the same order of Chebyshev function nuder the same specification. In general, inverse Chebyshev function has the preferable characteristics in terms of the delay characteristics and the time-domain performances compare with Chebyshev function. However, for the even order n, inverse Chebyshev function does not realize in the doubly-terminated ladder network which has preferable sensitivity characteristics because of the finite value at ${\omega}={\infty}$. In this paper, the modified inverse Chebyshev function with $\mid$H($j^{\infty}$$\mid$=0 s proposed to realize the passive doubly-terminated ladder network for the n even or odd. The modified inverse Chebyshev function characteristics ars studied in the frequency and time domain, and then, realize the passive doubly-terminated ladder network.

• Journal of Korean Clinical Nursing Research
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• v.21 no.3
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• pp.277-292
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• 2015

Purpose: The purpose of this study was to develop a Clinical Ladder System (CLS) model for staff nurses working in inpatient units of tertiary care hospitals in Korea. Methods: The study was carried out in 2 steps. First, a nursing competence evaluation scale was developed. Second, evaluation of the nursing competences, qualifications, and professional activities of 230 nurses from five tertiary care hospitals was done by 49 head nurses between Feb. and Dec., 2014. Nurses were selected by head nurses according to their clinical experience and expected behavioral characteristics at each level of the ladder. Results: A nursing competence scale was developed consisting of 5 subcategories (clinical practice, ethical practice, education, leadership, and professional development) and 11 elements, and 5 levels of behavioral indicators for each element. Cronbach's alphas for the entire tool and subcategories were over .853 and stability of the scale was confirmed. There were significant differences in nursing competence according to the 5 levels of the ladder. Conclusion: The findings indicate that the proposed CLS model with a standard score for nursing competence, recommended or obligatory criteria for qualifications and professional activities provides a good tool for developing nurses' competences and retaining excellent nurses in clinical practice.

• Journal of Korean Critical Care Nursing
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• v.3 no.1
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• pp.1-13
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• 2010

Purpose: This study was designed to evaluate ICU nurses' clinical competence according to clinical ladder by job analysis tool for the evaluation tool development of clinical ladder development program, Methods: Data was collected using the ICU nurses job analysis tool from 148 ICU nurses who work for 6 ICUs of A hospital in S city, Results: The mean clinical competence score of the subjects was 3.03 on a 4 point scale, Competence score was increasing as ICU clinical ladder was higher (F=35.18, p<.001). Step_1 was the lowest and step_4 was higher than step_3 from Scheffe post hoc test, Result of multiple regression showed that ICU clinical ladder and ICU clinical nursing education explained 52.1% (F=38.83, p<.001) of ICU nurse's clinical competence. Conclusion: ICU nurses' clinical competence can be evaluated using ICU nurse's job analysis tool. Further researches is needed on job description according to clinical ladder for performance and evaluation.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.6
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• pp.633-641
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• 2017

The aim of this study is to investigate the effects of intermittent ladder-climbing exercise training on mitochondrial biogenesis and ER stress of the cardiac muscle in high fat diet-induced obese middle-aged rats. We induced obesity over 6 weeks of period in 40 male Sprague-Dawley rats around 50 weeks old, and were randomly divided into four experimental groups: chow, HFD, exercise+HFD, and exercise+chow. The exercising groups underwent high-intensity intermittent training using a ladder-climbing and weight exercise 3 days/week for a total of 8 weeks. High-fat diet and concurrent exercise resulted in no significant reduction in body weight but caused a significant reduction in visceral fat weight (p<0.05). Expression of $PPAR{\delta}$ increased in the exercise groups and was significantly increased in the high-fat diet+exercise group (p<0.05). Among the ER stress-related proteins, the expression levels of p-PERK and CHOP, related to cardiac muscle damage, were significantly higher in the cardiac muscle of the high-fat diet group (p<0.05), and were significantly reduced by intermittent ladder-climbing exercise training (p<0.05). Specifically, this reduction was greater when the rats underwent exercise after switching back to the chow diet with a reduced caloric intake. Collectively, these results suggest that the combination of intermittent ladder-climbing exercise training and a reduced caloric intake can decrease the levels of ER stress-related proteins that contribute to cardiac muscle damage in obesity and aging. However, additional validation is required to understand the effects of these changes on mitochondrial biogenesis during exercise.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.503-515
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• 2018

The aim of this study was to develop a list of nursing competency for nurses' continuing education, and to propose a competency-based continuing education system according to nurses' clinical ladder. The definition of nursing competency was extracted by analyzing 10 studies. Also, the knowledge base of each nursing competency was confirmed through Carper and Chinn & Kramer's research. Nurses' clinical ladder and preliminary items of nursing competency behavior indicators were verified by seven experts for content validity. The results of this study were as follows; Nursing competencies were defined as 'evidence-based patient care', 'education and counseling', 'nursing management and leadership', 'law and ethics', 'professional value and development', 'research and policy development'. In addition, the validity of the 4 stages of clinical ladder and the 24 indicators of nursing competency were confirmed by experts. These findings suggest that the competency-based continuing education system according to the clinical ladder will be utilized as an effective human resource development strategy for improving the professionalism of nurses.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.4
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• pp.3-19
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• 2009

This paper proposes efficient scalar multiplication algorithms based on Montgomery ladder method. The proposed algorithm represents the scalar as ternary or quaternary and applies new composite formulas utilizing only x coordinate on affine coordinate system in order to improve performance. Furthermore, side-channel atomicity mechanism is applied on the proposed composite formulas to prevent simple power analysis. The proposed methods saves at least 26% of running time with the reduced number of storage compared with existing algorithms such as window-based methods and comb-based methods.

• Korean Journal of Ichthyology
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• v.21 no.4
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• pp.262-272
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• 2009

Upstream behavior of glass eels was examined in an experimental eel-ladder at a laboratory of the National Fisheries Research and Development Institute from March to May in 2008. The study was made under various environmental factors and conditions affecting the upstream migration of glass eels in order to design a functional ladder that would allow the passage of glass eels. The experimental eel-ladder consisted of an upper freshwater chamber and a lower sea water chamber; glass eels in sea water can move up to the upper freshwater chamber through the slope (eel-ladder) between them. The optimal condition of the eel-ladder was estimated by comparing the number of glass eels that moved upstream depending on various conditions. Since the glass eels actively moved up the slope to river water rather than to reservoir water or tap water, the experiment was realized using river water. A significantly higher number of glass eels moved up during the spring tide than during the neap tide, and during night than during the day. Upstream movement was significantly higher during high tide than during low tide. Glass eels effectively moved up through a slope of less than $30^{\circ}$ and water-flow velocity lower than 0.4 m/sec. The fish preferred a coarser ladder bed covered with small gravels, brush or carpet.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.511-519
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• 2021

This study examined the perception of life felt by low-income people in middle-aged and elderly people by enhancing the population structure of Korea, which is entering an aging society. For the analysis, the variables that need from the 2019 welfare panel data provided by the Ministry of Health and Welfare were selected. The final 1,684 samples were selected from the panel samples of 14,918 people, from the '60-70s' of 'low income class', by removing the unresponsive and insincere samples. In particular, this study defined as a dependent variable as a 'ladder of life' measured in panel data, and analyzed the personal characteristics and life satisfaction factors affecting 'ladder of life'. As a result of the analysis, most of the personal characteristics were found to be influential factors of the "ladder of life" when considering only personal characteristics as an influential factor for the dependent variable "ladder of life". Also, as a result of examining the interaction effect on the economic state variable, there was no significant interaction effect. This shows that the health condition is more important than the economic condition as the influential factor on the ladder of middle-aged elderly people. Therefore, the recognition of the elderly 'ladder of life' should improve the awareness of the elderly's life by various 'environmental factors', both internal and external, rather than the personal conditions and environment of the elderly. In other words, a plan to present a positive alternative to their perception of life will be needed.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2776-2778
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• 2011