• Journal of Korea Port Economic Association
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• v.31 no.3
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• pp.93-105
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• 2015

The purpose of this study is to outline the strategic implications of a structure analysis and trends of transferred air cargoes for the main airports of the North Asian region for 13 years from 2000 to 2012. To do so, it analyses the concentration levels using a Gini coefficient and Hirschmann Herfindahl index and represents the competitive positioning with regard to the main East Asian airports using the BCG framework and shift-share analysis. Currently, the concentration level is getting weaker in response to the emergence of Chinese airports in the north-east region. It is likely that the steady growth of air cargo of Shanghai airport (PVG) has caused the increase in concentration levels in the region. Seoul airport (ICN) may be directly in competition with PVG for air cargo in the region, giving consideration to reducing or maintaining an average increase ratio of air cargoes of ICN, NRT (Tokyo), and KIX (Osaka) for same period. In the same sense, the average increase in ratio for ICN for same period yields 1.3%, which is far behind the 6.2% and 5.2% of the north-east region and PVG respectively. Additionally, shift-share effect analysis indicates that ICN lost 422,180 tons in the north-east region during the same period, suggesting that transferred cargoes might have been forwarded to PVG.

• Journal of the Korea Convergence Society
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• v.7 no.4
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• pp.107-121
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• 2016

This study aimed to seek the way of effectively managing job stress of shift work nurses, to improve nursing performance, the influence of job stress of shift work nurses on nursing performance through convergence research. A total of 244 questionnaires obtained by a survey targeting nurses, who were doing shift work in a university hospital located in B city, in the period from March 2 to 15, 2015 were analyzed using the SPSS 21.0 program. As a result, the mean score of job stress was 3.57 points, and the mean score of nursing performance was 3.69 points. Job stress made a significant positive(+) influence on the sub-dimensions of interpersonal duty. Therefore, efforts should be made to more accurately identify shift work nurses' job stress and efficiently manage the nursing personnel. Moreover, if shift work nurses' job stress is effectively managed by preparing practical job stress management intervention programs for continuous improvement of nursing performance, high quality medical services will be provided through high quality nursing practice.

• The Korean Journal of Community Living Science
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• v.17 no.1
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• pp.55-65
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• 2006

The major purposes of this paper are (1) to explore korean rural planning as subplanning of nation planning and regional planning, (2) to explore functional change of korean rural areas, (3) and suggest appropriate policy for functional change of rural society in Korea. I divided korean rural planning into five periods according to its paradigm shift. In the first period of rural planning lay emphasis on food self-supply, antipoverty and improvement of living condition. In the second period of rural planning lay emphasis on food self-supply, green revolution and income gap mitigation between urban and rural areas. In the third period of rural planning lay emphasis on integrated rural development. In the fourth period of rural planning lay emphasis on multifunctionality of agriculture. In the fifth period of rural planning Korea government announced a new policy and lay emphasis on balanced national development. Food supply used to be most important function of rural areas, but it is weakened in recent days. The role as axis for balanced national development become another important function of rural areas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8A
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• pp.752-759
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• 2010

The low power consumption is the most important design factor for the In-Body communication system of WBAN. The conventional PSSK (Phase-Silence-Shift-keying) modulation technique can be regarded as an extension from PSK modulation. And this PSSK has better power efficiency than PSK modulation, and higher spectral efficiency than FSK modulation. PSSK modulation is to transmit two orthogonal symbols. The transmission power can be lowered because the symbol rate in signal period becomes half. BER performance is improved because transmission power is lower and the modulation symbol distance is widened. In addition, PSSK preserve the low-power and increase the data rate than FSK. In this paper, we analyzed existing PSSK and like to propose a new PSPM (Phase-Shift-Position-Modulation) modulation scheme. This PSPM is evaluated in terms of considered bandwidth efficiency and BER performance, compared with the PSSK. This PSPM modulation method transmits the information data by both PSK symbol data and symbol position data, so that we can significantly improve the power efficiency. New proposed PSPM method could be very useful for the In-body communication that requires the most power efficient system.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.2
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• pp.131-137
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• 2013

In this paper, the phase-shift full-bridge DC/DC converter with fixed-phase operation inverter is proposed. The proposed circuit consists of two full-bridge inverters which are connected in parallel. While one full-bridge inverter operates as the fixed-phase, it regulates the output voltage by adjusting the phase of the other inverter. During the normal operation period, the proposed circuit makes the less amount of conduction loss of the primary switches and secondary synchronous rectifiers, as well as the less amount of the current ripple of the output inductor, than the conventional phase-shift full-bridge DC/DC converter does. Also, it achieves high efficiency by reducing the snubber loss of the secondary synchronous rectifier. To sum up, the present inquiry analyzes the theoretical characteristics of the proposed circuit, and shows the experimental results from a prototype for 450W power supply.

• Physical Therapy Korea
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• v.19 no.1
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• pp.10-18
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• 2012

The purpose of this study was to determine the effects of weight shift training with joint mobilization on the ankle joint passive range of motion (PROM), balance capacity and gait velocity in hemiplegic patients. Fourteen subjects were randomly assigned to either the experimental group (EG) or the control group (CG), with seven subjects in each group. The EG received weight shift training with joint mobilization in the paretic leg's subtalar joint in order to increase ankle dorsiflexion. The CG received general physical therapy training. Both groups received training five times a week over a period of two consecutive weeks. The figures for PROM of ankle dorsiflexion on the paretic leg, the functional reach test (FRT), the timed up and go (TUG) test, and gait velocity were recorded both before and after the training sessions for both groups. The EG's results in gait velocity, the FRT and the TUG test improved after training (p<.05). The PROM of ankle dorsiflexion improved both in the EG and the CG (p<.05), the EG demonstrated a significantly higher increase (p<.05) than that of the CG. The results of this study suggest that increased joint mobilization positively affects balance and gait velocity of hemiplegic patients. Further studies with a greater sample size are necessary in order further prove the accuracy of the results of this study.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.95-100
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• 2020

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. The representative type of the degeneration is wear of tool or machine. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore a periodic preventive resetting the process is necessary. The total cost consists of three items: adjustment cost (or replacement cost), non-conforming cost due to product out of upper or lower limit specification, and quality loss cost due to difference from the process target value and the product characteristic value among the conforming products. In this case, the problem of determining the adjustment period or wear limit that minimizes the total cost is called the 'process mean shift' problem. It is assumed that both specifications are set and the wear level can be observed directly. In this study, we propose a new model integrating the quality loss cost, process variance, and production volume, which has been conducted in different fields in previous studies. In particular, for the change in production volume according to the increasing in wear level, we propose a generalized production quantity function g(w). This function can be applied to most processes and we fitted the g(w) to the model. The objective equation of this model is the total cost per unit wear, and the determining variables are the wear limit and initial process setting position that minimize the objective equation.

• Journal of Korean Critical Care Nursing
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• v.10 no.1
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• pp.1-12
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• 2017

Purpose: This study aimed to estimate the appropriate nurse staffing ratio in intensive care units (ICUs) by measuring nursing workload based on patient's severity and needs, using the Korean Patient Classification System for critical care nurses. Methods: The data were collected from January 18 to February 29, 2016 using a standardized checklist by observation or self-report. During the study period, 723 patients were included to be categorized from I to IV using the patient classification system. Measurement of total nursing workload on a shift was calculated in terms of hours based on the time and motion method by using tools for surveying nursing activities. The nursing activities were categorized as direct nursing care, indirect nursing care, and personal time. Total of 127 cases were included in measuring direct nursing time and 18 nurses participated in measuring indirect and personal time. Data were analyzed using descriptive statistics. Results: Two patients were classified into Class I (11.1%), 5 into Class II (27.8%), 9 into Class III (50%), and two into Class IV (11.1%). The amount of direct nursing care required for Class IV (513.7 min) was significantly more than that required for Class I (135.4 min). Direct and indirect nursing care was provided more often during the day shift as compared to the evening or night shifts. These findings provided the rationale for determining the appropriate ratio for nursing staff per shift based on the nursing workload in each shift. Conclusions: An appropriate ratio of nurse staffing should be ensured in ICUs to re-arrange the workload of nurses to help them provide essential direct care for patients.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.1
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• pp.45-50
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• 2021

Machines and facilities are physically or chemically degenerated by continuous usage. The representative type of the degeneration is the wearing of tools, which results in the process mean shift. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore, a preventive maintenance is necessary at some point. The problem of determining the maintenance period (or wear limit) which minimizes the total cost is called the 'process mean shift problem'. The total cost includes three items: maintenance cost (or adjustment cost), non-conforming cost due to the non-conforming products, and quality loss cost due to the difference between the process target value and the product characteristic value among the conforming products. In this study, we set the production volume as a decreasing function rather than a constant. Also we treat the process variance as a function to the increasing wear rather than a constant. To the quality loss function, we adopted the Cpm+, which is the left and right asymmetric process capability index based on the process target value. These can more reflect the production site. In this study, we presented a more extensive maintenance model compared to previous studies, by integrating the items mentioned above. The objective equation of this model is the total cost per unit wear. The determining variables are the wear limit and the initial process setting position that minimize the objective equation.

• Sleep Medicine and Psychophysiology
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• v.6 no.1
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• pp.68-75
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• 1999

Objectives: We intended to observe changes in sleep patterns and mood states of night-shift workers following light exposure. We also estimated the degree of tolerance of light exposure. By studying these, we investigated the possibility of applying light therapy to night-shift workers for improving their adaptation. Methods: Twelve night-shift nurses working at Yong-In Mental Hospital volunteered to participate in this study. The study consisted of 3 parts: 1) night-shift control study; 2) light exposure study; 3) day-shift control study. All the nurses accomplished 3 parts of the study, each of which continued for 3 days, except one nurse who did not participate in day-shift control study. During light exposure study, nurses were exposed to bright light for 4 hours from 1AM to 5AM. Sleep patterns were evaluated with wrist actigraphy and automatic sleep analysis program. Mood states and side effects of light exposure were assessed with self-report scales. Results: Sleep period time, total sleep time, and sleep efficiency were increased following light exposure compared with night-shift control study. Light exposure study showed no difference from day-shift control study in above-mentioned sleep parameters. Daily fluctuation of sleep efficiency was less prominent during light exposure study than during night-shift control study. During light exposure study, the subjects felt more elated and energetic in the evening after daytime sleep than during night-shift control study. None of the subjects complained of severe side effects related to light exposure on the third day of light exposure. Tolerance of side effects was noted to develop with the repetition of light exposure. Conclusion: Light exposure improved the daytime sleep of night-shift workers to the level of normal nighttime sleep, making the subjects more elated and energetic. Side effects of light exposure were found to be tolerable. Light exposure seems to be safely applicable to night-shift workers for their adaptation.