• Korean Journal of Adult Nursing
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• v.24 no.5
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• pp.509-519
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• 2012

Purpose: This retrospective study was designed to examine the frequency of unplanned extubation, and to identify the related factors of unplanned extubation in medical intensive care unit patients. Methods: Data were collected from medical records of patients who received intubation in a medical intensive care unit. One hundred eighteen patient charts were selected for the study. The Patient Severity Classification Scale and unplanned extubation risk factors were examined. Data were analyzed with descriptive statistics, $x^2$-test, Fisher's exact test and Mann-Whitney U test. Results: The incidence of unplanned extubation was 11 (9.32%) out of 118 patients who had undergone intubation. There were statistically significant differences between the unplanned extubation and work shift ($x^2$=61.52, p=.001), ventilation mode (p=.001), number of days of ventilator application (U=366.00, p=.038) and administration of sedatives (p=.025). Conclusion: Unplanned extubation is affected by the following variables: a) whether a nurse is in night shift, b) whether ventilation is mandatory, c) duration of ventilation use and d) administration of sedatives.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.89-97
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• 2014

As the digital control technologies in automotive industry have advanced, electronic control units(ECUs) play a key-role to improve system performance. Transmission control unit(TCU) is a shifting controller for automatic transmission of which major functions are to determine the shift and manage the shifting process considering the various sensor signal on transmission and driver's commands. As with any ECU in vehicle, TCU performs complex algorithms such as shift control, diagnostic and failsafe functions. However, firmware design analysis is hardly possible by the reverse engineering due to code protection. Transmission simulator is a hardware-in-the-loop simulator which enables TCU to work in normal mode by simulating the electrical signal of TCU interface. In this research, diagnosis and failsafe algorithm implemented on commercialized TCU is analyzed by using the transmission simulator that is developed for wheel loader construction vehicle. This paper gives various experimental results on the proportional solenoid current trajectories for different operating modes, error detection criterion and limphome mode gears for all the possible cases of clutch malfunction. The derived results for conventional TCU can be applied to the development of inherent TCU algorithms and the transmission simulator can also be utilized for the test of TCU to be developed.

• The Korean Journal of Food And Nutrition
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• v.33 no.3
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• pp.266-278
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• 2020

This study was conducted with 375 workers in Changwon to examine the effects of working patterns on dietary habits and health. A self-administered questionnaire was conducted July 22 October 30, 2019. According to the results of the dietary habits and health related factors analysis, non-shift administrative workers showed significantly higher rates of green tea intake (p<0.05), and shift production workers showed significantly higher smoking rates (p<0.001) and waist circumferences (p<0.01). According to the results of the Pearson's correlation coefficient analysis, work hours showed negative correlations with job satisfaction (r=0.22, p<0.01) and positive correlations with perceived stress level (r=0.14, p<0.01). Temporary workers showed negative correlations with feel job satisfaction(r=0.14, p<0.01), perceived stress level (r=0.12, p<0.05), and concern about health (r=0.13, p<0.05). Diabetes showed positive correlations with hypertension (r=0.20, p<0.01), low HDL cholesterolemia (r=0.22, p<0.01), abdominal obesity (r=0.13, p<0.05), and hypertriglyceridemia(r=0.22, p<0.01). Based on these results, this researcher proposes that continuous attention and support of industries and communities are necessary for nutritional education and counseling relative to improving workers' dietary lives as well as disease prevention and control.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.143-151
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• 2001

During the past several years, the major interests of car manufacturers in development of automatic transmission were in durability and shift quality. However, a large number of researches for improving shift quality that are based on dynamic characteristics of shifting mechanism have been rarely adopted in the developing process because it is quite difficult to predict the shifting performance from the dynamics simulation. One of the important reasons for the difference between simulation results and experiments arises from the automatic transmission hydraulic system that consists of many valves with high order model and shows a lot different dynamics to temperature variation. In this work, hardware-in-the-loop simulation system for automatic transmission was developed f3r improving the accuracy of simulated result by combining the real-time simulation model with the real hydraulic system. The real-time simulation for automatic transmission model excluding hydraulic system is executed with TI's TMS320C31 DSP and the interfacing board which includes 12bit A/D, PWM signal generator and driver, serial driver ,etc is designed for acquiring the simulation data and signal interface with hydraulic system. We verified the proper operation and correctness of shifting result by comparing the off-line simulation result with that of HILS and experimental result which was performed on transmission dynamometer driven by electric motor.

• Journal of Hydrogen and New Energy
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• v.30 no.6
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• pp.485-489
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• 2019

Hydrogen is known to be a clean fuel which does not generate a green house gas during the combustion. However, about 8 kg of carbon dioxide is generated during the course of producing 1 kg of hydrogen through reforming, water gas shift reaction and pressure swing adsorption in order to obtain a high purity hydrogen over 99.999% by volume. In this work, carbon dioxide generation is estimated according to four kinds of natural gas compositions supplied by Korea Gas Corporation and regarding natural gas as pure methane. For the simulation of the modeling, PRO/II with PROVISION V10.2 at AVEVA was utilized and Peng-Robinson equation of state with Twu's alpha function was selected.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.3
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• pp.131-137
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• 2005

This paper describes a new approach to the algorithm and fundamental characteristics of the device for monitoring the leakage currents flowing through zinc oxide (ZnO) surge arresters. In order to obtain a technique for a new on-line monitoring device that can be used in the deterioration diagnosis of ZnO surge arresters, the new algorithm and on-line leakage current detection device for extracting the resistive and capacitive currents using the phase shift addition method were proposed. The computer-based on-line monitoring device can sense accurately the power frequency leakage currents flowing through ZnO surge arresters. The on-line leakage current monitoring device of ZnO surge arresters proposed in this work has the high sensitivity compared to the third harmonic leakage current detection devices. As a consequence, it was found that the proposed leakage current monitoring device would be useful for forecasting the defects and degradation of ZnO surge arresters.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.37-43
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• 2020

This study proposes a 7kW low-voltage DC-DC converter (LDC) using a coupled inductor (CI) for heavy hydrogen electric transport vehicles. The LDC uses a phase-shift manner for soft switching. SiC-MOSFET is used to reduce the loss of reverse recovery current through the use of a high switching frequency. LDC is require large transformer and inductor because of large output current. The size of transformer and inductor can be reduced by deviding the transformer and inductor into two pieces each. This work presents the experimental results of the proposed circuit.

• Safety and Health at Work
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• v.13 no.1
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• pp.3-8
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• 2022

Background: This study aims to allow the development of efficient measures to improve occupational health of shift-working nurses focusing on job stress, health promotion behavior, resilience, and sleep disturbance. Methods: It was conducted on a subject panel of 137 nurses who were aware of the purpose of the study and agreed to participate. They worked three shifts at a tertiary hospital or a general hospital located in metropolitan city B. The collected data were analyzed by the independent t test and one-way analysis of variance and post-tested by Scheffe's test, Pearson's correlation coefficients, and multiple linear regression analysis using SPSS/WIN 25.0. Results: The significant influencing factors on sleep disturbance were of those whose subjective health status was 'normal' (b = 0.29, p < .001), 'not healthy' (β = .40, p < .001), who have job stress (β = .22, p = .003), and who have health promotion behavior (β = -0.17, p = .023). The overall explanatory power was 31.1% (F = 16.31, p < .001). Conclusion: Through this study, nurses' subjective health status and job stress of working shifts were found to be important factors influencing the sleep disturbance level, and the most influencing factor was identified as the subjective health status.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.1022-1028
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• 2024

A neutronics study of a supercritical CO₂-cooled fast reactor core for nuclear propulsion has been performed in this work. The thermal power of the reactor core is 30 MWth and a ceramic UO₂ fuel can be used to achieve a 20-year lifetime without refueling. In order to make a compact core with inherent safety features, the drum-type reactivity control system and folding-type shutdown system are adopted. In addition, we suggest a cold shutdown system using gadolinium as a spectral shift absorber (SSA) against flooding. Although there is a penalty of U-235 enrichment for the core embedded with the cold shutdown system, it effectively mitigates the increment of reactivity at the flooding of seawater. In this study, the neutronics analyses have been performed by using the continuous energy Monte Carlo Serpent 2 code with the evaluated nuclear data file ENDF/B-VII.1 Library. The supercritical CO₂-cooled fast reactor core is characterized in view of important safety parameters such as the reactivity worth of reactivity control systems, fuel temperature coefficient (FTC), coolant temperature coefficient (CTC), and coolant temperature-density coefficient (CTDC). We can say that the suggested core has inherent safety features and enough flexibility for load-following operation.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.50.1-50.11
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• 2023

Background: The rise in telecommuting or non-face-to-face work owing to the coronavirus disease 2019 pandemic has fueled conversations regarding the "right to disconnect." Although evidence suggests that receiving work-related communications through telecommunication devices outside of work hours may lead to various symptoms and illnesses, limited research has been undertaken on these symptoms. This study therefore aims to investigate the correlation between receiving work communications through telecommunication devices after work hours and the occurrence of work-related headaches and eyestrain in full-time, non-shift white-collar workers. Methods: This study used data from the 6th Korean Working Conditions Survey. The frequency of using telecommunication devices for work purposes outside of working hours was divided into five categories: "Every day," "Several times a week," "Several times a month," "Rarely," and "Never." Work-related headaches and eyestrain were categorized based on a "yes" or "no" response to the survey questions. Descriptive statistics, χ² tests, and multiple logistic regression analyses were performed using SPSS 27.0. Results: After adjusting for sex, age, income level, education, occupation, workplace size, work hours, and sleep disorders, the odds ratio (OR) of work-related headaches and eyestrain based on frequency of telecommunication device usage were as follows: "rarely" (OR: 1.292; 95% confidence interval [CI]: 1.111-1.503), "several times a month" (OR: 1.551; 95% CI: 1.249-1.926), "several times a week" (OR: 1.474; 95% CI: 1.217-1.784), and "every day" (OR: 1.548; 95% CI: 1.321-1.813). Conclusions: Employees who use telecommunication devices for work after regular hours are more susceptible to experiencing work-related headaches and eyestrain compared to those who do not. However, there is a dearth of research examining the physical and mental health impacts of using telecommunication devices for after-hours work. Furthermore, the existing preventative measures in Korea are insufficient. Consequently, it is imperative to develop effective measures and conduct additional research to address this issue.