• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.221-229
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• 2015

The purpose of study was to broaden our knowledge on the productivity and cost of thinning operations which has become increasingly practiced in Korea. The thinning operations were conducted in a 40-year old larch (Larix leptolepis) stand, including chainsaw felling and processing at the stump, followed by yarding tree-length logs using a Koller K301-4 tower yarder. The logs were further processed and sorted into 1.8 m and 3.6 m log piles at the landing. We used a standard time study method to evaluate key variables that affect the productivity of thinning operations. The total stump-to-pile operational cost was $41,707won/m^3$. The highest cost activity was the yarding phase which cost $20,083won/m^3$ (48.2% of the total cost), followed by the costs of processing treelength materials into marketable log lengths ($12,143won/m^3$; 29.1%), and then by the costs of sorting/piling the processed logs ($5,039won/m^3$; 12.1%). It was interesting to see that felling and processing trees at the stump had low costs at $1,315won/m^3$ (3.2%) and $3,127won/m^3$ (7.5%), respectively. We used the detailed time study data to develop regression equations which were to predict yarding productivity. Our analysis showed that harvesting system cost was highly sensitive to the number of logs, yarding distance and lateral distance per turn, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.161-163
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• 2010

In this study, it was accomplished the analysis of apartment house shape and the work factor productivity of the form work for the application of rational construction cost in apartment house. The form work is highly depended on the manpower in frame construction, and it has been a high impact during estimating of frame work cost.

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.292-300
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• 2014

The construction progress control is very important because there are many unexpected factors affecting time schedule delay and cost overruns. A complicated measure including item quantity and inherent time and costs is used to monitor the progress. Another element to be considered is a productivity, which is cost effectiveness because productivity is primarily measured by the costs. Productivity is stated as constant in-place value divided by inputs such as worker-hour. The main purpose of this paper is to analyze the productivity of structural formwork using a 3D BIM. In order to achieve the research objective, an integrated model of a BIM with a daily foreman's report is developed. The quantities being extracted from a 3D model and information are integrated with manpower utilized. The developed model is applied to a case project to measure and analyze the productivity in terms of individual building and work crew team. The results are discussed and further research topics will be addressed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.42-43
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• 2014

Few studies on crew productivity has been conducted, although the data is significant for time and cost estimation. Crew productivity data was collected for over 9 months from a nuclear power plant and analysed in order to identify factors driving the productivity. It was revealed that the crew productivity of form work, rebar work and concrete pouring work was 45.64(㎡/crew·day), 2.93(t/crew·day), 110.25(㎡/crew·day) on average respectively. Moreover, 'nightwork', 'No. of workers per crew' and 'total work amount' were identified as drivers.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.191-192
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• 2011

The construction projects contain a lot of variables and risk affecting productivity. The duration of the project must be recognized important as for quality, unit cost and safety. There is need for improving work efficiency by investigating relationship of works to prevent delay. This study focuses on analysing the delay factors of steel staircase system to suggest regression model that enables construction productivity estimation. The position of the observers and construction delay factors were expressed by the independent variable of the regression model and productivity was expressed by a dependent variable. This paper suggests quantitative productivity and it is expected that will be helpful estimating application in construction new technologies.

• Proceedings of the Safety Management and Science Conference
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• 2004.11a
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• pp.131-141
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• 2004

This study deals with the procedure of safety improvement, productivity increase, and tact-time reduction through setting up the system about preventive maintenance. Actually, it is hard to establish and carry out preventive maintenance, even though we recognize the importance of the system concerning time, cost, labor, and so forth. In this study in the viewpoint of cost we are for achieving maximum efficiency by change and reduction of planning process adapted to the special work group. At first we briefly will mention the kind, the necessity, and the concept of preventive maintenance, and then divide the equipment used in the assembly line into the two whether it is necessary or not by way of estimating the breakdown loss, comparing with general establishment of preventive maintenance and modifying it to the case. At the second step we will establish the operation system of plan management related to production and quality in the special case. Check period and category will be set by dividing the assembly equipment into LCL and Focus in the third step. The forth step will contain the operation procedure in detail. And then we must make check and repair record periodically. Finally, on the basis of the record the selection of checking of significance will be conducted. This results in safety improvement, tact time reduction, and productivity improvement.

• Journal of the Korea Safety Management & Science
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• v.7 no.1
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• pp.101-115
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• 2005

This study deals with the procedure of safety improvement, productivity increase ,and tact-time reduction through setting up the system about preventive maintenance. Actually, it is hard to establish and carry out preventive maintenance, even though we recognize the importance of the system concerning time, cost, labor, and so forth. In this study in the viewpoint of cost we are for achieving maximum efficiency by change and reduction of planning process adapted to the special work group. At first we briefly will mention the kind ,the necessity ,and the concept of preventive maintenance ,and then divide the equipment used in the assembly line into the two whether it is necessary or not by way of estimating the breakdown loss ,comparing with general establishment of preventive maintenance and modifying it to the case. At the second step we will establish the operation system of plan management related to production and quality in the special case. Check period and category will be set by dividing the assembly equipment into LCL and Focus in the third step. The forth step will contain the operation procedure in detail. And then we must make check and repair record periodically. Finally, on the basis of the record the selection of checking of significance will be conducted. This results in safety improvement, tact time reduction, and productivity improvement.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.80-83
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• 2005

The competitiveness of the manufacturing company is evaluated in terms of line productivity, quality cost, inventory level, logistics efficiency, and so on. The productivity is defined by the number of products divided by the number of workers within the given operation time. Increasing the productivity is not easy to man-operated situation in the line, since it heavily depends on the standard time of the workers. This paper deals with the productivity of the Back Light Unit assembler for TFT-LCD, and proposes the methodology of investigating the optimal process by simulation of Arena.

• Journal of Preventive Medicine and Public Health
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• v.43 no.4
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• pp.352-361
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• 2010

Objectives: This study estimated the annual socioeconomic costs of food-borne disease in 2008 from a societal perspective and using a cost-of-illness method. Methods: Our model employed a comprehensive set of diagnostic disease codes to define food-borne diseases with using the Korea National Health Insurance (KNHI) reimbursement data. This study classified the food borne illness as three types of symptoms according to the severity of the illness: mild, moderate, severe. In addition to the traditional method of assessing the cost-of-illness, the study included measures to account for the lost quality of life. We estimated the cost of the lost quality of life using quality-adjusted life years and a visual analog scale. The direct cost included medical and medication costs, and the non-medical costs included transportation costs, caregiver's cost and administration costs. The lost productivity costs included lost workdays due to illness and lost earnings due to premature death. Results: The study found the estimated annual socioeconomic costs of food-borne disease in 2008 were 954.9 billion won (735.3 billion won-996.9 billion won). The medical cost was 73.4 -76.8% of the cost, the lost productivity cost was 22.6% and the cost of the lost quality of life was 26.0%. Conclusions: Most of the cost-of-illness studies are known to have underestimated the actual socioeconomic costs of the subjects, and these studies excluded many important social costs, such as the value of pain, suffering and functional disability. The study addressed the uncertainty related to estimating the socioeconomic costs of food-borne disease as well as the updated cost estimates. Our estimates could contribute to develop and evaluate policies for food-borne disease.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.523-526
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• 2002

In the bearing wall systems, a form work has a lot of room that saves cost because it takes a substantial proportion of construction cost. Therefore the systemic and efficient methods are required in the form work. This study focuses on methods that enhance the quality and the productivity of form work and presents the kicker form as an alternative plan to simplify the form work through being modular and automatical it. Work sampling method is used for productivity measurement. It is expected that it will reduce the work process and improve the Qualify and the podructivity of construction.