• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.2
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• pp.67-74
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• 2007

The objective of this research is to select the most effective technique among task related techniques(motion & time study, job redesign, physical environment improvement) for improving work efficiency in shipbuilding enterprise. This study consists of several principal steps. The first step is to design critical criteria in evaluating work efficiency in ship-building enterprises. The second step is to develop sub-criteria of the critical criteria. The third step is to develop a four level AHP(Analytic Hierarchy Process) structure using the critical criteria, sub-criteria and techniques among task related techniques. The fourth step is to develop the pairwise comparison matrix at each level of AHP structure, which was based on survey data collected at the H heavy industry. And the last step is to select the most effective technique among task related techniques using AHP analysis. The result of AHP analysis has shown clear difference in priority among task related techniques in terms of work efficiency of the shipbuilding enterprise: The reduction of normal time is more important than the reduction of allowance time in improving of the work efficiency. Motion & time study is the most important technique for the reduction of normal time, and physical environment improvement is the most important technique for the reduction of allowance time as well.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.31-37
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• 2006

The objective of this research is to select the most effective technique from task related techniques(motion & time study, job redesign, physical environment improvement) for improving work efficiency in shipbuilding enterprise. This study consists of several principal steps. The first step is to design critical criteria in evaluating work efficiency in shipbuilding enterprises. The second step is to develop sub-criteria of the critical criteria. The third step is to develop a four level AHP(Analytic Hierarchy Process)structure using the critical criteria, sub-criteria and techniques from task related techniques. The fourth step is to develop the pairwise comparison matrix by each level of AHP structure, which was based on survey data collected at the H heavy industry. And the last step is to select the most effective technique from task related techniques using AHP analysis. The result of AHP analysis has shown clear difference in priority among task related techniques in terms of work efficiency of the shipbuilding enterprise: The reduction of normal time has more importance than the reduction of allowance time, motion & time study techniques are most important for the reduction of normal time, physical environment improvement is most important for the reduction of allowance time as well.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.559-568
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• 2017

Objective: The aim of this study is to investigate the effective managerial factors influencing dose reduction of the nozzle dam installation and removal tasks ranking within top 3 in viewpoint of average collective dose of nuclear power plant maintenance job. Background: International Commission on Radiation Protection (ICRP) recommended to reduce unnecessary dose and to minimize the necessary dose on the participants of maintenance job in radiation fields. Method: Seven sessions of nozzle dam installation and removal task logs yielded a multiple regression model with collective dose as a dependent variable and work time, number of participants, space doses before and after shield as independent variables. From the sessions in which a significant reduction in collective dose occurred, the effective managerial factors were elicited. Results: Work time was the most important factor contributing to collective dose reduction of nozzle dam installation and removal task. Introduction of new technology in nozzle dam design or maintenance job is the most important factor for work time reduction. Conclusion: With extended task logs and big data processing technique, the more accurate prediction model illustrating the relationship between collective dose reduction and effective managerial factors would be developed. Application: The effective managerial factors will be useful to reduce collective dose of decommissioning tasks as well as regular preventive maintenance tasks for a nuclear power plant.

• International Journal of Control, Automation, and Systems
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• v.5 no.6
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• pp.614-620
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• 2007

This paper considers vibration suppression of a mechanical transfer system, where the work is connected with the hand flexibly. We adopt the idea of jerk reduction of the hand. From the equation of motion, we first derive a state equation including the jerk and acceleration of the hand, but excluding the displacement and velocity of the work. Then, we design optimal state feedback for a suitable cost function, and show by simulation that jerk reduction of the hand is effective for vibration suppression of the work and improvement of the settling time. Since state feedback including the jerk and acceleration is not practical, we propose a computation method for optimal feedback using displacements and velocities in the state only.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.15-18
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• 2009

Due to its high dependency of manpower, construction work has several difficulties in terms of quality control, imbalance of supply and demand of qualified manpower, safety management for them and improvement of production. Such problems related to the management can be at some degree solved by introducing an automation facility. Since the unique environment of a construction site in the past was not structured, it is very hard to introduce a facility to automate construction work from operation of the equipment to assignment of where to work. This is a preliminary research for automation of construction work. In this study, the trend of development of a cutting-edge technology, RTLS, was researched and analyzed in order to review the possibility of utilizing RTLS in construction work and present a control mechanism for construction equipment. Although the presented mechanism is at the concept stage, which still has lots of restrictions to be solved, the application of the RTLS will be very much feasible. That is, if linkage of the study between the RTLS and the automation of construction is built, it will be expected to contribute to many fields such as cost reduction through efficient and systemic management, the reduction of construction period and precise construction as well as raising the level of the automation of domestic construction work.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1543-1550
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• 2007

This study was grasped an instance of a leisure activities about a construction engineers through the questions as to a need, a plan, a preference, a time and a main cause of a leisure activities. An increase of an income and a reduction of a work time have investigated an influence on a leisure cost and time. This study suggested a good method for an improvement of a leisure activities.

• Journal of the Korea Institute of Building Construction
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• v.12 no.4
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• pp.401-414
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• 2012

The adoption of Green Frame is expected to provide economic benefits, since construction costs are reduced by the in-situ production of precast concrete column and beam. The cost reduction can ultimately be realized by saving transportation costs and the overhead and profit of PC plants. The cost structure of Green Frame, which is built up using composite precast concrete members, is similar to that of a bearing-wall structure, but the difference in construction process has resulted in some cost differences for a few items. In particular, production and installation is the principal work involved in Green Frame made by precast concrete members, while form and concrete work is the principal work for a bearing-wall structure. As such, the rental time and fee for a tower crane should be compared through time analysis. To verify reliability, this study focused on developed residential projects to estimate the construction costs. Through this analysis, it was found that the costs of Green Frame were 1.57% lower than the costs of bearing-wall structure. The results of this study will help in the development of a management plan for the structural work of Green Frame.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.93-99
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• 1999

A try was carried out to reduce lead time of die manufacturing. That is to make manual machining and finishing work time shorter by improving CAD/CAM modeling methods, so called with "separate modeling" and "relief modeling". The manual machining and finishing manual work time were reduced adapting the novel CAD/CAM modeling methods. Ultimately we accomplished much reduction of the lead time of die manufacturing.f die manufacturing.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.16 no.28
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• pp.203-209
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• 1993

In Factory Automation environments such as FMS, the formation of machine-part based on GT should be considered. The purpose of this study is to develop a economic heuristic algorithm which considers various elements such as unit processing time, subcontract cost, and functional operation cost, machine processing capacity etc. When this proposed approach is applied to the real situation expected benefits are as follows: the reduction of production lead time work in process, labor force, tooling, rework and scrap, setup time, order time delivery, and paper work, etc.

• Korean Journal of Construction Engineering and Management
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• v.6 no.5 s.27
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• pp.139-147
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• 2005

During a typical construction project, a contractor nay often find that the time originally available or normally expected to perform its work has been severely reduced. To finish the project by the completion date, the contractor is forced to find a way to speed up the progress of its work to compensate for the reduction in available time. The most frequent initial reaction of contractors to this situation is to increase on-site manpower by working longer time (overtime), adding more workers (overmanning), or implementing shift work (shift work) to increase the rate of progress. The goals of this study were to investigate how these three methods affect labor productivity and to quantify their impact on labor productivity by analyzing real project data collected from sheet metal contractors and mechanical contractors in the US.