• 한국자동차공학회논문집
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• 제7권5호
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• pp.96-106
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• 1999

In this study, the advanced shift control algorithm for parallel type hybrid drivetrain system with automated manual transmission(AMT) is proposed. The AMT can be easily realized by mounting the pneumatic actuators and sensors on the clutch and shift levers of the conventional manual transmission. By using the electronic-controlled AMT, engine and induction machine, it is possible to achieve the integrated control of overall system for the efficiency and the performance of the vehicle. Performing the speed control of the induction machine and the engine, the synchronization at gear shifting and the smooth engagement of clutch can be guaranteed. And it enables to reduce the shift shock and shorten the shift time. Hence, it results in the improvement of shift quality and the driving comfort of the vehicle. Dynamometer-based experiments are carried out to prove the validity of the proposed shift control algorithm.

• 한국직업건강간호학회지
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• 제17권1호
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• pp.45-54
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• 2008

Purpose: This study was conducted to compare and estimate sleep patterns and health status of the shift and non-shift factory workers. Methods: The subjects of this study were 290 male workers in 13 companies, which manufacture automobile parts in Daegu, Korea. Survey data were collected from March 5th, 2007 to April 5th, 2007. PSQI was scored to check the quality of sleep, ESS for excessive daytime sleep disorder, ISI for insomnia, and SF-36 for health status. The data were analyzed by $X^2$ and t-test using SPSS 12.0 for windows. Results: There was a difference in quality of sleep patterns between shift and non-shift workers (p=.033). A difference in the pattern of excessive daytime sleep (P=.005) and in the degree of insomnia (p=.030) were observed between the two groups. However, there were no significant difference in health status between the two groups. Conclusion: Based on these results, shift workers are in need of careful and continuous monitoring regarding sleep disorders and we need to develop health promotion programs including sleep hygiene for shift workers.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1472-1481
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• 2001

In this paper, an advanced shift controller that supervises the shift transients with adaptive compensation is presented. Modern shift control systems for vehicle automatic transmission are designe d to provide smooth transients for passengers' comfort and better component durability. In the conventional methods, lots of testing and calibration works have been done to tune gains of the controller, but it does not assure optimum shift quality at all times owing to system variations often caused by uncertainties in shifting hydraulic systems and external disturbances. In the proposed control scheme, an adaptive compensation controller with intelligent supervisor is implemented to achieve improved shift quality over the system variations. The control input pattern which generates clutch pressure commands in hydraulic actuating systems, is updated through a learning process to adjust for each subsequent shift based on continuous monitoring of shifting performance and environmental changes. The proposed algorithm is implemented and evaluated on the experimental test setup. Results from the experimental studies for several operation modes show both improved performance and adaptability of the proposed shift controller to uncertain changes of the shifting environment in vehicle power transmission systems.

• 한국산학기술학회논문지
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• 제17권6호
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• pp.546-559
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• 2016

본 연구의 목적은 교대근무 간호사를 대상으로 스트레스 반응, 신체활동, 수면위생과 수면의 질의 관계를 분석하고, 수면의 질에 미치는 영향요인을 파악하기 위함이다. 연구대상은 경남 C시에 소재한 대학병원과 종합병원에서 교대근무 하는 간호사 168명이었고, 자료수집기간은 2016년 3월 25일부터 2016년 3월 31일까지 였다. 연구도구는 Pittsburgh Sleep Quaility Index, Stress Response Inventory, Korean version International Physical Activity Questionnaire Short Form 및 Sleep Hygiene Practice Scale을 사용하였다. SPSS WIN 18.0을 이용하여 빈도, 백분율, 평균, 표준편차, t-test, ANOVA 및 사후검증, Pearson correlation coefficient, Hierarchical mutiple regression으로 분석하였다. 연구결과, 교대근무 간호사의 수면의 질은 7.35점(범위 0-21점), 스트레스 반응은 2.20점(범위 1-5점), 신체활동량은 3986MET-min/week, 수면위생은 2.73점(범위 1-6점)이었다. 수면의 질은 교대근무 간호사의 특성 중 교대근무 경력, 건강상태, 일주기 리듬에서 유의한 차이를 보였다. 수면의 질에 영향을 미친 변수는 교대근무경력, 수면위생, 스트레스 반응, 신체활동으로 나타났으며 설명력은 40%(F=8.16, p<.001)였다. 따라서, 교대근무 간호사의 수면의 질을 향상시키기 위하여 수면위생 증진 교육을 실시하고, 스트레스 반응을 줄이기 위한 전략을 사용하도록 하며, 중간정도의 신체활동을 권장하는 것이 필요하다.

• 한국산업보건학회지
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• 제25권4호
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• pp.566-572
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• 2015

Objectives: The major objective of this study was to analyze insomnia after the change to consecutive day shift from day and night shift in a motor assembly factory. Materials: Data were collected at before and after shift system change through a survey conducted by a labor union. We analyzed transition of PSQI(Pittsburgh Sleep Quality Index) among 222 workers by separating the day shift week and night shift week. The cut-off point of insomnia was 8.5 on the PSQI. Results: Mean PSQI in the day shift week significantly did not decrease, going from $6.36{\pm}3.23$ to $6.46{\pm}3.00$(p=0.612 by paired t-test), Mean PSQI for night shift week significantly decreased from $8.31{\pm}3.36$ to $6.19{\pm}3.18$(p<0.001 by paired t-test). However, mean PSQI in the day shift week increased from $6.33{\pm}3.83$ to $7.11{\pm}2.86$ in ${\geq}50$ years(p=0.085, by repeated measured ANOVA). Mean PSQI score in the night shift week improved more in the married group(from $8.38{\pm}3.27$ to $6.12{\pm}3.18$) than in the non-married group(from $7.82{\pm}3.27$ to $6.12{\pm}3.18$)(p=0.038, by repeated measured ANOVA). Conclusions: The change to consecutive day shift improved insomnia in night shift. However, insomnia in the day shift week was worsened among those more than 50 years old.

• 대한기계학회논문집A
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• 제22권3호
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• pp.663-670
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• 1998

Most of feedback shift controllers developed in the past have fixed control parameters tuned by experts using a trial and error method. Therefore, those controllers cannot satisfy the best control performance under various driving conditions. To improve the shift quality under various driving conditions, a new self-organizing controller(SOC) that has an optimal control performance through self-learning of driving conditions and driver's pattern is designed in this study. The proposed SOC algorithm for the shift controller uses simple descent method and has less calculation time than complex fuzzy relation, thus makes real-time control passible. PCSV (Pressure Control Solenoid Valve) control current is used as a control input, and turbine speed of the torque converter is used indirectly to monitor the transient torque as a feedback signal, which is more convenient to use and economic than the torque signal measured directoly by a torque sensor. The results of computer simulations show that an apparent reduction of shift-transient torque is obtained through the process of each run without initial fuzzy rules and a good control performance in the shift-transient torque is also obtained.

• 대한기계학회논문집A
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• 제22권3호
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• pp.654-662
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• 1998

Shift quality of an automatic transmission in a vehicle is mainly affected by transient pressures in the hydraulic system during shifting. In this study, dynamic modelings of the hydraulic system and the power train of an automatic transmission are made systematically by a bond-graph method. The dynamic characteristics of the line pressures and clutch/brake pressures during shiftings are investigated by simulations and verified by experiments. The effects of clutch/brake pressures on the shift torque are also investigated through driving simulation.

• 품질경영학회지
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• 제12권2호
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• pp.6-10
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• 1984

A model for obtaining optimal resetting period and optimal target value of the process quality level is proposed when the quality characteristic is subject to a linear shift in mean. Different sales conditions are considered where good items can he sold at a regular price and bad items at a discounted one. Some numerical examples are also given.

• Journal of Mechanical Science and Technology
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• 제14권5호
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• pp.508-517
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• 2000

For shift quality improvement, torque sensors are currently too expensive to be used on production vehicles. To achieve smooth acceleration shift, the reference trajectory of the clutch slip speed for accomplishing the shift process within a designated shift completion time and its relationship with the clutch actuating torque were suggested by Jeong and Lee (1999). In order to facilitate the proposed algorithm, nonlinear estimators for necessary information such as the axle shaft torque, clutch friction and turbine torque were designed using only speed sensors. Accounting for the modeling error, a control law for this indirect smooth shift was proposed based on the above mentioned suggestions. Simulation results of the proposed estimators and shift controller were presented and further considerations for practical applications are discussed.

• 한국자동차공학회논문집
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• 제4권4호
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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.