• Journal of Digital Convergence
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• v.12 no.6
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• pp.265-270
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• 2014

The working-day movement model, which implemented in the ONE simulator, supports the environments similar to the real life by using the transportation. However, there is no taxi movement model in the working-day movement model. So, we implemented a taxi movement model in the ONE simulator as the previous work. It is changed significantly for the simulation results of routing protocols in the ONE simulator. In this paper, we analyze the performance evaluation of the DTN routing protocol such as an epidemic routing protocol using our taxi movement model in the ONE simulator.

• Journal of the Korean Society of Visualization
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• v.17 no.3
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• pp.52-58
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• 2019

Thermal performance and flow patterns inside the closed loop pulsating heat pipe (CLPHP) were experimentally investigated. For investigating the effect of working fluids, CLPHP was filled with various working fluids including methanol, acetone and ethanol. The thermal resistance was calculated by temperatures in evaporator and condenser and flow patterns were visualized by a digital camera. The thermal resistances for all fluids were decreased as the heat increases. Flow patterns change from static slug to elongated slug flows, bulk circulation and annular flows as the heat increases. Dry-out occurs after annular flows. For reasonable comparison of thermal performances, normalized CHF, Kutateladze number (K_u), was compared. Even though ethanol has smallest CHF, K_u of ethanol is similar with that of methanol. In addition, acetone has the highest K_u that means CLPHP with acetone provides the higher thermal performance compared with CLPHP with other fluids.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.131-139
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• 2005

This study concerns the performance of boiling heat transfer in two-phase closed thermosyphons with various helical grooves. Distilled water, methanol, ethanol have been used as the working fluids. In the present work, a copper tube of the length of 1200 mm and 14.28 mm of inside diameter is used as the container of the thermosyphon. Each of the evaporator and the condenser section has a length of 550 mm, while the remaining part of the thermosyphon tube is adiabatic section. A experimental study was carried out for analyzing the Performances of having 50, 60, 70, 80 and 50 helical grooves. A Plain thermosyphon having the same inner and outer diameter as the grooved thermosyphons is also tested for comparison. The type of working fluid and the numbers of grooves of the thermosyphons with various helical grooves have been used as the experimental parameters. The experimental results have been assessed and compared with existing theories. The results show that the number of grooves and the type of working fluids are very important factors for the operation of thermosyphons. The helical grooved thermosyphons having 50 to 60 grooves in water, 60 to 70 grooves in methanol and ethanol shows the best heat boiling heat transfer coefficient.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.5
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• pp.384-392
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• 2006

Reported are the heat transfer characteristics of a two-phase loop thermosyphon (TLT) with nanofluids consisted of nano-size silver particles and distilled water as the working fluid. The nanofluids used in the present study are dispersed solutions with various amount of silver nanoparticle in distilled water. It is seen from the present study that the heat transfer performance of the test TLT with nanofluids increased as much as about 2 times higher than that of a TLT with pure water as the working fluid based on same heat flux. The study also showed that there was no deterioration of the TLT performance with time, up to a period of 8 days of continuous operation which implies that there was no coagulation of nanoparticles within the working nanofluid during the operation of the test TLT.

• The Journal of Economics, Marketing and Management
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• v.3 no.4
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• pp.13-20
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• 2015

This study examined the relationship between working capital management and performance of listed companies Stock Exchange in Tehran. A total of 40 companies from the cement industry for the period 2007 to 2010 of which only 25 were selected for this study had the condition. In order to achieve the objectives, this study surveys the exploration of correlation regression analysis and used the curve obtained, the regression equation. To test the hypothesis, quantitative analysis was used as a method. The results showed a negative relationship between the variables of working capital management and the company's performance and the only variable cash conversion cycle did not show a significant relationship. There is often a negative correlation between the variables studied. This study is based on five assumptions impact of working capital management on corporate profitability is examined. Therefore, the results suggest that the variables in working capital (average collection of receivables, average inventory turnover period, the average net debt and average transaction cycle) and net operating profit is significant negative correlation Net cash conversion cycle and only illustrates the relationship is not significant. Thus, it showed that in debt collection and debt payment period, the turnover of inventory and net trade cycle to reduce the profitability of companies will increase.

• Journal of Korean Public Health Nursing
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• v.17 no.2
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• pp.317-332
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• 2003

This study attempts to investigate the relations between the types of communication, the job satisfaction. and the nursing performance of the staff nurses. The subjects of this study were the 114 nurses working in general wards, intensive care units, and the emergency rooms of the general hospital in Kyongbuk province. They were asked to answer the questionnaires as regards the types of communication and job satisfaction, and their performance of nursing, and these were evaluated by the head nurses, and their direct seniors. The data were collected for 10 days from the September 17 to 26, 2002. According to the purpose of the study, descriptive analysis, ANOVA. Pearson correlation coefficient, and stepwise multiple regression were applied for the data analysis using SPSS 10.0. The results are as follows : 1. The types of communication of staff nurses showed that the upward communication was $3.12\pm0.56$. the downward communication was $3.56\pm0.42$. the horizontal communication was $2.98\pm0.44$. and the informal communication was $2.59\pm0.49$. It showed that the most frequent communication was the downward communication. 2. In terms of the job satisfaction, there was significant difference according to the length of the period working for one ward (F=5.95, p=0.003), 3. The performance of nursing was significantly different according to the age (F=23.52, p=0.000), the working duration as a nurses (F=21.9, p=0.000), the types of nursing unit (F=5.33, p=0.002), and the working duration in present nursing unit (F=15.87, p=0.000). 4. In terms of communication type, the job satisfaction was associated with quality of the upward communication (F=6.23, p=0.003), the downward communication (F=5.78, p=0.004), and the horizontal communication (F=11.73, p=0.000) There were no association between the types of communication and the performance of nursing. 5. There was a positive correlation between the communication and the job satisfaction. And the downward communication (r=0.398) showed the greatest correlation with the job satisfaction. There was no statistically significant correlation between the communication and the performance of nursing. And the upward communication (r=-0.058) showed a negative, though not significant correlation with performance of nursing. 5. There was a positive correlation between the communication and the job satisfaction. And the downward communication (r=0.398) showed the greatest correlation with the job satisfaction. There was no statistically significant correlation between the communication and the performance of nursing. And the upward communication (r=-0.058) showed a negative. though not significant correlation with performance of nursing. 6. The stepwise multiple regression result showed that the downward communication accounts for $15.8\%$ (p=0,000) of the job satisfaction.

• Journal of Korean Academy of Nursing
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• v.27 no.4
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• pp.765-776
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• 1997

Hospitals accomodate patients who have a high risk of infection due to reduced immunity as well as people who require surgical, medical or other treatments. Consequently, the role of clinical nurses, who come into close contact with these patients is very important in the control of nosocomial infection. This study was done to investigate and compare the level of perception of the importance of the control of nosocomial infections as well as the level of actual performance, and the level of satisfaction with the control of nosocomial infection by the clinical nurses. Thus, the purpose of this study is to contribute basic data for improving policies and educational programs to control nosocomial infection. A summary of the survey results is as follows. 1) The means of scores on all categories of the inquiry were 4. 51 for awareness 4.42 for actual performance, and 3.20 for satisfaction, of a possible high score of 5.00. 2) Correlations of the level of perception of importance between characteristics of nurses and hospital control of nosocomial infection differed significantly according to the type of hospital establishment type (p=.005), age(p=.000), career(p=.000), position (p=.002), and regular conferences on infection control in working departments(p=.003), Correlation of the level of actual performance between characteristics of nurses and hospital control of nosocomial infection diffesed significantly according to type of hospital(p=.000), hospital size (p=.009), working department(p=.000), age(p=.000), career (p=.000), school career(p=.040), position (p=.000), education experience on nosocomial infection(p=.020), and regular conferences on infection control in working department(p=.000). Correlation of degree of satisfaction between characteristics of nurses and hospital control of nosocomial infection also differed significantly according to the type of hospital establishment (p=.003), working department(p=.000), age (p=.000), and regular conferences on infection control in working department (p=.000). 3) Correlation between clinical nurses, level of perception of importance and actual level of performance for the control of nosocomial infection was relatively positive (r=.57, p=.000). Correlation between clinical nurses degree of satisfaction and level of actual performance for control of nosocomial infection was relatively positive (r=.47, p=.000). Correlation between clinical nurses, level of perception of importance and degree of satisfaction degree with the control of nosocomial infection was also relatively positive (r=.27, p=.000).

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.651-660
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• 1996

The purpose of this study was to examine and analyze the degrees and the influence factors of job satisfaction of dietitians working in hospitals in relation to performance of duty in their works and to provide effective management of hospital dietitians for high quality health and food service in hospital. The questionaire was prepared with reference to the previous studies on job satisfaction of dietitians working in hospitals throughout the nation. 201 dietitians in the country were surveyed. The period of research was from January 20 to February 28, 1995. The results are as follows. 1) In regard to the degree of job satisfaction of hospital dietitians, they showed the highest degree of job satisfaction in the relationships with fellow dietitians followed by worth and self-confidence, aptitude and interests, relationships with cooks, job stability, degree of recognition of the dietitians competence, supervision of the superiors, degree of application of professional knowledge, work load, wage level, degree of recognition of the importance of duty, cooperative relationships with load, wage level, degree of recognition of the importance of duty, cooperative relationships with doctors, degree of performance of clinical work, the number of dietitians, the prromotion system, and welfare system in that order. On the other hand, they showed the highest dissatisfaction with food service facilities. 2) The influence factors on job satisfaction are as follows. (1) Wage factor : Shorter weekday working hours and higher bonuses make greaster job satisfaction (R2=0.3115). (2) Working condition factor : Larger number of monthly holidays(R2=0.5142), shorter weekday working hours(R2=0.1077), longer previous food service experience and computer utilization (R2=0.1432) make greater job satisfaction. (3) Welfare factor : Welfare system (R2=0.4132) and promotion system (R2=0.1624) have to do with computer utilization. Job stability has to do with marital status and computer utilization (R2=0.1165). consequently, those married dietitians who use computers show higher job satisfaction. (4) Human relationship factor : Smaller mumber of patients receiving food makes greater job satisfaction (R2=0.1334). (5) Superivision factor : Shorter weekday working hours and larger number of monthly holidays make greater job satisfaction (R2=0.1709). (6) Achievement factor : Marriage, larger number of dietitians(R2=9.2293), age, larger number of monthly holiday, higher monthly wages and computer utiliazation (R2=0.1088) make greater job satisfaction. (7) Speciality factor : Marriage, longer current hospital tenure, higher position and working in seoul(R2=0.1142) make higher job satisfaction. (8) Job inclination factor : working in general hospitals rather than in oriental hispitals, working in seoul(R2=0.1776) and better bonuses(R2=0.1078)make greater job satisfaction. As a result, the following is suggested for the job satisfaction of hospital dietitions on the basis of this study : hospital dietitians can achieve miximum job satisfaction through smooth relationships with coworkers, and the responsible managers should improve welfare and working conditions for the job satisfaction of hospital dietitians.

• Journal of Drive and Control
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• v.13 no.4
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• pp.14-22
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• 2016

This paper presents a stochastic and predictive working-risk-assessment algorithm for excavators based on a one-layer laser scanner. The one-layer laser scanner is employed to detect objects and to estimate an object's dynamic behaviors such as the position, velocity, heading angle, and heading rate. To estimate the state variables, extended and linear Kalman filters are applied in consideration of laser-scanner information as the measurements. The excavator's working area is derived based on a kinematic analysis of the excavator's working parts. With the estimated dynamic behaviors and the kinematic analysis of the excavator's working parts, an object's behavior and the excavator's working area such as the maximum, actual, and predicted areas are computed for a working risk assessment. The four working-risk levels are defined using the predicted behavior and the working area, and the intersection-area-based quantitative-risk level has been computed. An actual test-data-based performance evaluation of the designed stochastic and predictive risk-assessment algorithm is conducted using a typical working scenario. The results show that the algorithm can evaluate the working-risk levels of the excavator during its operation.

• Nuclear Engineering and Technology
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• v.11 no.1
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• pp.29-45
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• 1979

In this paper. nuclear characteristics of TRIGA Mark-III has been analyzed in detail for six different fuel options. Presently, 70 w/o enriched FLIP fuels are adopted for TRIGA core to improve fuel lifetime. However, such highly enriched fuels are not easily obtained due to nonproliferation treaty. This research examines the possible substitution for FLIP fuels with high density fuels without reducing the nuclear performance. This work will provide long-time plan for TRIGA operation.