• Journal of the Korean Society of Safety
• /
• v.23 no.6
• /
• pp.7-13
• /
• 2008

It is important to prevent roll failure in hot rolling process for reducing maintenance cost and production loss. The relationship between rolling pass schedule and the work roll wear profile will be presented. The roll wear pattern is related with roll catastrophic failure. The irregular and deep roll wear pattern should be removed by On-line Roll Grinder(ORG) for roll failure prevention. In this study, a computer roll wear prediction model under real process working condition is developed and evaluated with hot rolling pass schedule. The method of building wear calculation functions for center portion abrasion and marginal abrasion respectively was used to develop a work roll wear prediction mathematical model. The three type rolling schedule are evaluated by wear prediction model. The optimum roll grinding methods is suggested for schedule tree rolling technique.

• Korean Journal of Construction Engineering and Management
• /
• v.6 no.1 s.23
• /
• pp.177-185
• /
• 2005

The purpose of this study is to develop a supporting tool for efficient management, at preconstruction phase, of the schedule risk that is able to generate at construction phase. The main contents of this study to develop a practical tool are as follows. First steel work was selected as a relevant trade and a risk breakdown structure focused on the process of steel work having large effect on total construction process was made. Secondly, the work flow considering schedule risk factor was made and schedule risks that must be managed preferentially through analyzing the grade of importance for risk was selected. Finally, based on above two procedure, the management form for schedule risk was developed It is necessary to accumulate abundant data for schedule risk for other construction process and to develop a manual and a schedule risk management system.

• International conference on construction engineering and project management
• /
• 2007.03a
• /
• pp.554-562
• /
• 2007

This study determined tact process paths by separating the finish works according to the properties of work areas and work relations in order to apply the tact schedule management to the finish works. In addition, by suggesting preparing and sharing the workflow charts, the experiments can be shared between the executors and any possible frictions between the specialist works can be identified in advance. In addition, any errors on the plan can be reviewed and modified through the measurement stage of tact plan attainment rate. The process of tact schedule management is improved with such tools and methods and the efficiency of the process through the application of cases was verified.

• Journal of Korean Clinical Nursing Research
• /
• v.27 no.2
• /
• pp.165-178
• /
• 2021

Purpose: To analyze nurses' shift work according to the government guidelines for night work and their perceptions of their work schedules. Methods: The study sample included 487 nurses who provided information on their schedules, including the normal working hours of each shift, and overtime per shift during September 2020. Nurses' perceptions were measured in terms of satisfaction, appropriateness for work-life balance, and fairness to their work schedule. Results: One-third of the respondents worked more than 40 hours per week. The average overtime hour was 1.14 hours per shift. Unsocial hours (8 pm to 6 am on weekdays, midnight to midnight on weekends and public holidays) accounted for 56.4% of all working hours. During their last night shift, on average, nurses worked 9.62 hours and had a break of 39 minutes, although 20.5% reported no break. Sixty-eight percent of nurses had at least one between-shift break shorter than 48 hours after a consecutive night shifts. Fifty-seven percent were satisfied with their schedule. One-third perceived their schedule as appropriate for work-life balance, and two-thirds perceived that days off on weekends and nights were fairly distributed within the unit. Working and overtime hours had an inverse relationship with all three aspects of nurses' perceptions. A higher proportion of unsocial hours and having no breaks during the night shift were associated with lower perceptions of fairness. Conclusion: Reducing working hours, ensuring breaks during night shifts, and increasing rewards for unsocial hours are required to improve nurses' perceptions and reduce turnover due to shift work.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.6
• /
• pp.1281-1286
• /
• 2009

Our government operates earned value management system (EVMS)of construction schedule and cost for improving earned management system of the construction projects. but There is two unification Method construction schedule and cost to estimate construction progress currently. This weight a staff work. therefore this study present unification method which operate integrate schedule and cost by using work task. In order to inflect verification and model of schedule and cost, this study develop prototype of EVMS.

• Journal of the Korean Society for Railway
• /
• v.12 no.1
• /
• pp.135-143
• /
• 2009

The majority of development projects fail to meet their target schedule and cost, with the overrun typically between 40 and 200 percent. These overruns happen because the planners underestimate the work or do not consider the need to rework at project planning. Representative schedule planning/management techniques such as Gantt Chart, PERT/CPM etc. that are used in domestic project planning are unable to reflect rework. This paper proposes a method to consider rework to provide more realistic estimates at schedule planning. Additionally, to prevent the underestimation of the work this paper proposes a simulation method that calculates a probabilistic estimated schedule and the associated variance based on the random variable modeling of individual task completion dates.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.1 no.1
• /
• pp.77-97
• /
• 1994

The circadian system represents a temporal order which is mediated by the mutual coupling of oscillators and by the synchronizing effects of zeitgebers. It is known that well-being of man depends partly on the maintenance of this order, and that repeated or long lasting disturbances to it such as shift work will Cause harmful effects. This study was a quasi-experimental study to test the effect of shift directions for the clinical nurses on the circadian rhythm. Fourteen nurses working at the general units of Y hospital were selected according to the established criteria. Fourteen subjects were assigned to a weekly shift but the directions of shift work were phase delay first and then phase advance or vice versa. Oral temperature, total sleeping time, frequency of sleep-wake cycle, fatigue, mental performance, and physical symptom were measured during these days except holidays. The data collection period was from April 26, 1993 to July 3, 1993. MANOVA and Wilcoxon signed rank test were used for statistical analysis. The results are summarized as follows. 1. Having worked on evening and night shifts in either phase delay or phase advance schedules, temperature rhythms of shift workers were gradually adapted to the new sleep-wake cycles. A complete adaptation to work on the night shift was achieved the sixth day of the night shift in the phase delay schedule compared to the partial adaptation to the work on the night shift in the phase advance schedule. Accordingly, by putting evening shift between day and night shifts, it will be possible for circadian rhythm to adapt easily to the night shift. 2. There were differences in the total sleeping time, frequency of steep-wake cycle, fatigue, and physical symptom except for mental performance between night shift and day, evening shift. This indicates further that shift workers working on the night shift have a hard time adapting to the shift work compared to the other shifts. 3. Evaluating all the acrophases of temperature rhythm either in phase delay or phase ad-vance schedules, it was shown that night to evening shift in the phase ad-vance schedule revealed the smallest phase move. Also phase advance schedule showed poorer adaptation to shift work than phase delay schedule in connection with total sleeping time, frequency of sleep-wake cycle, fatigue, mental performance, and physical symptom. It is suggested, taken together, these findings reflect that phase delay schedule facilitated the degree of adjustment to the shift work compared to the phase advance schedule.

• Korean Journal of Construction Engineering and Management
• /
• v.1 no.4 s.4
• /
• pp.82-90
• /
• 2000

An integrated cost and schedule control is a noteworthy alternative of the separate control method which is commonly used in the domestic construction industry. In Korea, some cost and schedule integration models have been applied partly by construction managers. But, these models have not been customized yet because they did not reflect the characteristics of the domestic construction industry. This study investigates the characteristics of domestic integration models analyzed through interviews with experts who have the experiences in applying cost-schedule integration models. Based on these surveys, this study suggests the strategy for the improvement of work packaging model in the domestic construction industry.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2006.11a
• /
• pp.722-726
• /
• 2006

Last Planner System (LPS) developed by Lean Construction Institute consists of four steps: Master Schedule, Phase Schedule, Lookahead Planning and Weekly Work Plan. This paper focuses on the process of measuring Percent of Plan Completed (PPC) at the Weekly Work Plan stage. PPC means the percentage of weekly assignments completed. According to the results of the researches that deal with PPC from many other countries, we can assure the benefits of using PPC. However, the concept of PPC is unfamiliar in Korea construction industry. This paper analyzes the cases in which PPC is applied in other countries and compares them with the production control system in Korean construction industry. The results of this research will provide the time management system for using PPC in Korea.

• Journal of the Korea Institute of Building Construction
• /
• v.9 no.1
• /
• pp.89-94
• /
• 2009

A study was performed the analysis for the schedule delay of the public housing. To perform this study, the first study existing research literature on the cause of the schedule delay was considered. The based on existing study, this study selected the cause of schedule delay. For check of the schedule delay, this study was compared the monthly schedule and the work diary. Survey was conducted for using the selected cause of schedule delay. And the importance was calculated for using the AHP method. In a case site, the cause of the schedule delay was analyzed. The last, the delay cause was presented the map of cause of effect the based on the delay cause of a case site.