• Journal of Mechanical Science and Technology
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• v.18 no.3
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• pp.471-480
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• 2004

Statistical simulation approaches are proposed to evaluate the shift feeling for a manual transmission. First, shift force simulator for the manual transmission is developed by considering the dynamic models of the external and internal linkage, synchronizer, and drivetrain. It is found that the shift force by the simulator shows a good correlation with the test results. Using the simulator, two kinds of statistical simulation approaches are proposed and the objective parameters that can be used to evaluate the shift feeling quantitatively are obtained. It is expected that the shift force simulator with the statistical approaches, developed in this study can be used as a useful design tool to evaluate the shift feeling in the initial design stage.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.107-117
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• 1996

The shift feeling, a driver experiences during gear shifting, is a major factor in manual transmission quality. Recently, the shift feeling has becoming more severe every year in proportion to the higher torque and revolution speed of today's automotive engine. In this paper, first, the diagram of a relation between cone angle, sleeve chamfer angle, and friction coefficient of ring is investigated for easy design of Synchromesh system. And then, methodology to solve the shift problems such as clashing noise and rough shift, ect. by analyzing the synchronization procedure in sequence and by investigating the shift waveform if presented.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.3
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• pp.85-97
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• 2000

In this paper, static and dynamic shift control stategies of CVT speed ratio are suggested. For the static shift control, in order to operate engine on the optimal operating region, a fuzzy control logic is used. In the fuzzy logic, S- factor that is defined as a degree of sportiness is introduced. Simulation results show that the static shift control strategy based on the fuzzy logic selects the optimal operating point automatically between the economy and the sporty mode corresponding to the driver's desire and the driving condition. For the dynamic shift control strategy, a shift speed map is suggested which determines the shift sped as fast or slow based on Δi, the difference between the desired speed ratio id and the actual speed ratio i, and throttle opening. It is seen from the simulation results that the CVT shift speed is determined by the dynamic shift control strategy to provide appropriate performance and comfort for the driver's demand and driving condition. Additionally, experiments are performed to investigate the dynamic performance of the shift speed for the lift foot up. From the experimental results, it is found that improved shift feeling can be obtained by the dynamic shift control strategy when lift foot up occurs.

• Journal of Korean Clinical Nursing Research
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• v.23 no.1
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• pp.54-63
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• 2017

Purpose: The purpose of this study was to compare the working status and Standard Shiftwork Index (SSI) between night shift-fixed nurses and rotating shift nurses. Methods: Participants were 367 nurses working as registered nurses at 7 different medical institutions. The data were collected from August 8, 2016 to September 30, 2016. Results: Night shift fixed nurses were more satisfied with work schedule than rotating shift nurses. Rotating shift nurses reported higher SSI scores, such as chronic fatigue, musculoskeletal problems, than night shift fixed nurses. In SSI's sub-items, rotating shift nurses reported higher scores, such as the amount of sleep, feeling well after sleep, heartburn or stomach-ache and heartbeat irregularities, than night shift fixed nurses. Conclusion: The results indicated that night shift fixed system might be an effective method to improve nurses' work satisfaction. It is necessary to figure out any suitable night shift fixed system based on the characteristics of each nursing organization. The SSI might be an useful tool to measure the nurses' satisfaction in reference to their work shift.

• Safety and Health at Work
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• v.6 no.3
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• pp.240-248
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• 2015

Background: Recovery from fatigue is important in maintaining night workers' health. This study compared the course of self-reported recovery after 2-week 12-hour schedules consisting of either night shifts or swing shifts (i.e., 7 night shifts followed by 7 day shifts) to such schedules consisting of only day work. Methods: Sixty-one male offshore employees-20 night workers, 16 swing shift workers, and 25 day workers-rated six questions on fatigue (sleep quality, feeling rested, physical and mental fatigue, and energy levels; scale 1-11) for 14 days after an offshore tour. After the two night-work schedules, differences on the $1^{st}$ day (main effects) and differences during the follow-up (interaction effects) were compared to day work with generalized estimating equations analysis. Results: After adjustment for confounders, significant main effects were found for sleep quality for night workers (1.41, 95% confidence interval 1.05-1.89) and swing shift workers (1.42, 95% confidence interval 1.03-1.94) when compared to day workers; their interaction terms were not statistically significant. For the remaining fatigue outcomes, no statistically significant main or interaction effects were found. Conclusion: After 2-week 12-hour night and swing shifts, only the course for sleep quality differed from that of day work. Sleep quality was poorer for night and swing shift workers on the $1^{st}$ day off and remained poorer for the 14-day follow-up. This showed that while working at night had no effect on feeling rested, tiredness, and energy levels, it had a relatively long-lasting effect on sleep quality.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.7-13
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• 2015

The production processes were reviewed through the injection analysis of the shift lever as a core component of an auto lever installed in the automatic transmission of cars. The injection analysis was carried out for the shift lever and rod among the components in a shift lever module. The shift lever and rod are designed for injection molding with the insertion of a tube, a pin cable plate, and a steel rod for securing the strength of the product. The charging time, failure of injection molding, weld line, air trap, and deformation were reviewed according to this insert. Analyses on various gate positions were carried out for reviewing the cultivation and deformation of fiber around major components, such as the generation section of manipulation feeling and assembly section, so that optimal gate conditions might be reviewed and reflected in the mold design. Finally, we plan to compare the analysis results with the production of trial products.

• Women's Health Nursing
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• v.24 no.3
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• pp.252-264
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• 2018

Purpose: To understand the essentials of rearing conflict experience by three shift nurses in advanced general hospitals. Methods: The design was a qualitative research of phenomenology. Participants were 7 shift nurses working in advanced general hospitals who were rearing young children. Data were collected individually through in-depth interview on their life experiences. Data were analyzed by Colaizzi's phenomenological methodology. Results: Eighteen themes were drawn from 256 meaningful experiences and these themes were integrated to six theme clusters. The most influencing themes were 'Regret that I cannot satisfy even the slightest wish', 'Fail to care for kids', and 'Mutual feeling to care giver between appreciation and inconvenience'. Other themes were as follows: 'Body and mind are broken', 'The need for a three-shift system to support nurses who are rearing children', 'Doing my best for work and child rearing'. Conclusion: The nature of three-shift nurses working in advanced hospital and caring kids is explained as 'lives with conflict' between work and home. This study suggests it is necessary to establish a 24-hour care center for 3-shift nurses to keep working while rearing their children.

• Clinical and Experimental Emergency Medicine
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• v.5 no.4
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• pp.240-248
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• 2018

Objective Determine differences between faculty, residents, and nurses regarding night shift preparation, performance, recovery, and perception of emotional and physical health effects. Methods Survey study performed at an urban university medical center emergency department with an accredited residency program in emergency medicine. Results Forty-seven faculty, 37 residents, and 90 nurses completed the survey. There was no difference in use of physical sleep aids between groups, except nurses utilized blackout curtains more (69%) than residents (60%) and faculty (45%). Bedroom temperature preference was similar. The routine use of pharmacologic sleep aids differed: nurses and residents (both 38%) compared to faculty (13%). Residents routinely used melatonin more (79%) than did faculty (33%) and nurses (38%). Faculty preferred not to eat (45%), whereas residents (24%) preferred a full meal. The majority (>72%) in all groups drank coffee before their night shift and reported feeling tired despite their routine, with 4:00 a.m. as median nadir. Faculty reported a higher rate (41%) of falling asleep while driving compared to residents (14%) and nurses (32%), but the accident rate (3% to 6%) did not differ significantly. All had similar opinions regarding night shift-associated health effects. However, faculty reported lower level of satisfaction working night shifts, whereas nurses agreed less than the other groups regarding increased risk of drug and alcohol dependence. Conclusion Faculty, residents, and nurses shared many characteristics. Faculty tended to not use pharmacologic sleep aids, not eat before their shift, fall asleep at a higher rate while driving home, and enjoy night shift work less.

• Korean Journal of Occupational Health Nursing
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• v.9 no.2
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• pp.86-93
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• 2000

This study was conducted to find out the degree of tiredness, accumulated tendencies of fatigues in accordance with 3 types of circadian rhythms and 3 types of perceived fatigue signs such as physical, psychological and neurosensory aspects in before and after work at night. Samples were chosen from the 217 intensive care units nurses working in 13 general hospitals which had 3 shift rotating systems, Data were collected from November to December in 1999. Two hundreds seventeen respondents were classified by 3 circadian types such as 59 morning, 110 middle and 48 evening. Circadian type was measured by the circadian type scale which was designed by ${\ddot{O}}stberg$ and Home (1976). in order to estimate the level of tiredness, the investigator used the fatigue checklist designed by the Labor and Health Institute of Japan(1970). Analysis was done by frequency a percentages, ${\chi}^2$ test and repeated measures ANOVA test. The result of this study were as follow: 1. In the general characteristics of the subjects circadian types, moderate type had the large proportion at 50.7% and morning type had 27.2% and evening type had 22.1%. 2. According to the 3 types of fatigue signs, the highest general tendency was 'General weakness' and 'Feeling of headsore' for physically perceived sign, 'Drowsiness' for psychological sign, and 'Uncomfortableness in sight seeing' for neurosensory sign. 3. The most frequently complained fatigue were observed in physical symptoms among physical, mental, and neurosensual symptoms. The percentage of complained was higher after night work than before the work started. 4. There was not any statistical significant difference between the circadian type and the degree of physical, mental, neurosensory fatigue. 5. There was not any statistical significant difference in regarding to each date of night shift except difference between 1st and 2nd days of fatigue perceived physically. Therefore, the study concluded that the fatigue perceived by night shift nurses might be related with shift working condition rather than circadian types.

• Clinics in Shoulder and Elbow
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• v.3 no.2
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• pp.79-86
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• 2000

Purpose: We analysed the clinical efficacy of inferior capsular shift operation in multidirectional instability of the shoulder joint in terms of functional aspects and patient's satisfaction Materials and Methods: From July, 1998 to March, 2000, we treated 23 cases of multidirectional instability of the shoulder joint with T-shaped inferior capsular shift and/or Bankart repair. All of them have complained of an experience about frank dislocations. Two of them has a voluntary component. We evaluated them according to complication, function, range of motion, stability and patient's satisfaction with an average follow-up of 15 months(the range of 9 to 27 months). Results: Eight cases were atraumatic multidirectional instability and coexisting Bankart lesion were present in 15. There was no redislocation, but one case of symptomatic subluxation, 3 cases of transient nerve palsy and 2 cases of feeling of laxity developed. Limitation of motion after surgery was an average of 3.4° in flexion, and 8.5° in external rotation. With Rowe scoring system, the clinical result was excellent or good in 22 cases and poor in one. According to American shoulder and elbow society, pain score improved to 1.4 from 6.1, and stability score also improved to 1.8 from 9.1. Conclusion: In multidirectional shoulder instability, one should pay attention to finding a coexisting Bankart lesion. In that case, adequate capsular volume reduction by using inferior capsular shift as well as repair of Bankart lesion is needed to get a good surgical outcome.