• 제목/요약/키워드: Time shift

검색결과 1,662건 처리시간 0.029초

Friction Coefficient, Torque Estimation, Smooth Shift Control Law for an Automatic Power Transmission

  • Jeong, Heon-Sul;Lee, Kyo-Ill
    • 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.

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Testing Procedure for Scale Shift at an Unknown Time Point

  • Song, Il-Seong
    • Communications for Statistical Applications and Methods
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    • 제3권1호
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    • pp.21-27
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    • 1996
  • A testing procedure is considered to the problem of testing whether there exists a shift in scale at an unknown time point whem a fixed number of observations are drawn successively in time. A test statistic based on squared ranks test for equal variances is suggested and its aymptotic distrbution is dereived. Small sample power comparisons are performed.

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귀금속 계열 촉매의 수성가스전환반응특성과 유효인자 (Noble metal catalysts for water gas shift reaction and their effectiveness factor)

  • 임성광;배중면;김기현
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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    • pp.514-517
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    • 2008
  • Water gas shift(WGS) is an important step in fuel process for fuel cells, and improperness of commercial WGS catalysts for use in fuel cell systems has prompted numerous researches on noble metal catalysts. A selected noble metal catalyst for water gas shift reaction(WGS) was prepared with various metal loadings. The prepared catalysts were tested under two feeding conditions. At moderate residence time, carbon monoxide conversion was much higher on the noble metal catalysts as compared to commercial high-temperature shift catalyst. Effects of metal loading were examined by activity tests at short residence time. Higher metal loading effected higher reaction rate. The kinetic data was fitted to simple reaction equations and effectiveness factor was estimated. The results suggest the necessity of a structural design for the highly active noble metal catalysts.

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호텔 요리사의 인간공학적 작업 위험성 평가 (A Heuristic Approach to the Shift-scheduling Considering the Balance of Work-load in Nuclear Power Plants)

  • 김대호;윤영수;이용희
    • 대한인간공학회지
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    • 제25권4호
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    • pp.1-7
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    • 2006
  • The purpose of this study is to develop an efficient algorithm for the management of the shift schedule in nuclear power plants in consideration with the ergonomic criteria and the regulatory codes. The ergonomic criteria considered are the work hours, overtime-work frequency and working time, start and finishing time of works, allocation of rest times and duty-offs, rotating of shifts, etc. to comply with the regulations such as the Labor Standard Act, the ILO Convention No. 171, 178, "the detailed content of a periodic safety review," enforcement regulations 19-2 of the Atomic Energy Act. The developed algorithm for the shift schedule program adopts a heuristic method to minimize the difference the workload for shift workers in nuclear power plants.

산업체 주.야간 근로자의 식생활 행동 및 영양소 섭취량 (A Study of the Eating Habits and Nutrient Intake of Industrial Workers Who Work Day and Night Shifts)

  • 박연옥;최인선;이성숙;오승호
    • 대한지역사회영양학회지
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    • 제7권5호
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    • pp.615-627
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    • 2002
  • The purpose of this study was to examine the eating habits and nutrient intake of industrial workers who work day and night shifts. In the area of percentage of skipped meals, the day shift workers responded that they usually skipped breakfast and the night shift workers often skipped lunch and dinner. The day shift workers answered that they skipped meals because of lack of time. The night shift workers cited poor appetite as their main reason for skipping meals. The intake of calories, Vitamin $B_2$ and calcium of the industrial workers who worked day and night shift was lower than the Korean RDA. The intake of iron of the male night shift workers was lower than the Korean RDA The intake of calories, protein, calcium, iron, Vitamin $B_2$and niacin, vitamin C of the female night shift workers was lower than the Korean RDA. In the area of nutrient intake, the night shift workers both male and female got lower scales than the day shift workers. The nutrient intake of the female night shift workers was the worst. Because they cook for themselves and live alone, their nutrient intake and eating habits were bad. The night shift workers were worse than the day shift workers and the female night shift workers were the worst. Considering the above results, night shift workers should correct their poor eating habits, their nutrient intake and have a well-balanced diet.

고장을 고려한 공정평균 이동에 대한 조정시기 결정 (Determination of Resetting Time to the Process Mean Shift with Failure)

  • 이도경
    • 산업경영시스템학회지
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    • 제42권4호
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    • pp.145-152
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    • 2019
  • All machines deteriorate in performance over time. The phenomenon that causes such performance degradation is called deterioration. Due to the deterioration, the process mean of the machine shifts, process variance increases due to the expansion of separate interval, and the failure rate of the machine increases. The maintenance model is a matter of determining the timing of preventive maintenance that minimizes the total cost per wear between the relation to the increasing production cost and the decreasing maintenance cost. The essential requirement of this model is that the preventive maintenance cost is less than the failure maintenance cost. In the process mean shift model, determining the resetting timing due to increasing production costs is the same as the maintenance model. In determining the timing of machine adjustments, there are two differences between the models. First, the process mean shift model excludes failure from the model. This model is limited to the period during the operation of the machine. Second, in the maintenance model, the production cost is set as a general function of the operating time. But in the process mean shift model, the production cost is set as a probability functions associated with the product. In the production system, the maintenance cost of the equipment and the production cost due to the non-confirming items and the quality loss cost are always occurring simultaneously. So it is reasonable that the failure and process mean shift should be dealt with at the same time in determining the maintenance time. This study proposes a model that integrates both of them. In order to reflect the actual production system more accurately, this integrated model includes the items of process variance function and the loss function according to wear level.

실시간 영상에서 물체의 색/모양 정보를 이용한 움직임 검출 알고리즘 구현 (The motion estimation algorithm implemented by the color / shape information of the object in the real-time image)

  • 김남우;허창우
    • 한국정보통신학회논문지
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    • 제18권11호
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    • pp.2733-2737
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    • 2014
  • 실시간 영상을 이용하여 움직임 검출을 하는데 사용하는 배경 차영상 기법에 의한 움직임 및 변화 영역 검출 방법과 움직임 히스토리에 의한 움직임 검출법, 광류에 의한 움직임 검출법, 움직임 추적을 위한 추적하려는 물체의 히스토그램의 역투영을 이용하면서 물체의 중심점을 추적하는 MeanShift와 물체의 중심, 크기, 방향을 함께 추적하는 CamShift, Kalman 필터에 의한 움직임 추적 알고리즘 등이 있다. 본 논문에서는 물체의 색상과 모양 정보를 이용한 움직임 검출 알고리즘을 구현하고 검증하였다.

Effects of Compelled Weight Shift on Balance Ability in Patients with Stroke

  • Son, Sung Min
    • The Journal of Korean Physical Therapy
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    • 제29권5호
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    • pp.255-258
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    • 2017
  • Purpose: This study aimed to investigate the effects of compelled weight shift in paretic lower limb training on balance ability in patients with stroke. Methods: Thirty-six individuals with hemiparesis, who were randomly assigned to a 10CWST (10 mm constrained -weight shift training) group, a 5CWST (5 mm constrained-weight shift training) group, and a control group participated in this study. Compelled weight shift training was performed in 3 sets of 5 min with a rest period of 1 min between sets. Both the 5CWST and 10CWST groups performed 5 times per week for 4 weeks. Static (mediolateral and anteroposterior sway velocities) and dynamic balance (mediolateral and anteroposterior distances) was assessed using the Good Balance system. Results: Significant differences were found in the M-L and A-P sway velocities, and the M-L sway distance. The M-L and A-P sway velocities, and M-L sway distance showed significantly large group effects (p<0.05), time effects (p<0.05), and group-by-time interaction (p<0.05). The post hoc analyses indicated that, following intervention, the 10CWST group showed more significant changes in the M-L and A-P sway velocities, and the M-L sway distance than the control group. Conclusion: These results suggest that the use of compelled weight shift in paretic lower limb training may be an effective method to improve balance ability in patients with stroke.

신생아중환자실 간호사의 간호업무량 분석 (Nursing Time Use in a Newborn Intensive Care Unit (NICU))

  • 전은경
    • 간호행정학회지
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    • 제6권1호
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    • pp.55-81
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    • 2000
  • This study examined nursing care in a Newborn Intensive Care Unit (NICU) by reviewing nursing activities for the newborns. Through direct observation, time used for nursing care according to the nursing activity, shift, day of the week, and position of the nurses was measured. This study was done on November 15, 21, 24, 1999 at a university medical center hospital and included eight nurses and 179 newborns as the study subjects. The data were collected from the medical records, and by using a nursing activity record for the NICU, and a nursing activity time record for the NICU. The first step in the data collection process was to develop a list of nursing activities which was done through a literature review, examination of medical affairs and duty records. Content validity was measured by a panel of three professors who were experienced clinicians. In the second step two pre-training sessions were held with three sophomore student nurses who then measured the time for each nursing activity using a stopwatch. The data were analyzed using frequencies for nursing activities, averages, percentages and ANOVA for differences between shift and between days of the week, and percentages and t-test for differences according to position of the nurse. The results are as follows: 1) The total number of activities was 156, direct or indirect nursing activities. Direct nursing activity classified according to physical, educational, emotional/social/economic/spiritual needs. There were 109 direct nursing activities in 16 fields. 2) The order of nursing activities, according to time required, was record keeping, nutritional care, measurement/observation, medication, hygiene care, examination and specimen collection, and checking supplies, and according to frequency, measurement/ examination, record keeping, nutrition care, hygiene care, elimination care and medication. 3) According to shift, direct care during the night shift at 313.4 minutes was the longest time and indirect nursing care during the night shift at 252.2 minutes was the highest time. 4) For days of the week, Monday had the highest time for direct care 275.8 minutes (34.6%) and Wednessday had the highest time for indirect nursing care 269.6 minutes (36.1%). 5) For nursing time according to position of nurse, general nurses had the highest for direct care (330.7 minutes), nurse managers for indirect nursing activities (239.0 minutes) and general nurses for individual private time (63.9 minutes). The results of this study show that the major nursing time consuming activities included record keeping, nutrition care and measurement/examination. For newborns, time needs to be allowed for care to be sensitive, sophisticated and specialized rather than concentrated on indirect nursing tasks such as record keeping. Therefore, it is imperative to develop computerized systems that support a systematic approach to record keeping which is more efficient. Moreover, nursing needs according to shift, day or position of nurse can be utilized in assessing nursing resources through a computerized process.

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TCU 제어로직 평가를 위한 AMT 모델 개발 (Development of Automated Mechanical Transmission Model to Evaluate TCU Control Logic)

  • 오주영;송창섭
    • 한국정밀공학회지
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    • 제27권3호
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    • pp.118-126
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    • 2010
  • The automated mechanical transmission(AMT) is composed of electronic control management(ECM) and automatic shift gear(ASG). The AMT has advantages which are high efficiency of manual transmissions(MT) and offer operation convenience similar to automatic transmissions(AT). However, it has defects that are the torque gap during gear shift transients and shift time is long. To reduce such defects, it is necessary practically to evaluate error and characteristics as developing simulation model before the control algorithm is applied. In this paper, models are composed of vehicle model and AMT shift control model. Particularly AMT shift control model consists of main clutch management model (MCM) and shift control management model(SCM). The developed models were verified by comparing the simulated and experimental results under the same operational conditions. It can also be used to evaluate shift algorithm.