• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.295-300
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• 2001

Additional costs as well as schedule delay are occurred due to change orders in today's construction projects. Additional costs, overhead calculation methods are of various types. In a foreign country cases, many claims related to the loss of labor productivity quote research statistics data. In domestic cases, the study of the reason why the loss of labor productivity occurs and its effect have not been performed. Therefore, this paper analyzes factors affecting lost productivity and a methodology is presented to estimate the lost productivity.

• Korean Journal of Construction Engineering and Management
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• v.6 no.5 s.27
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• pp.69-77
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• 2005

Change is inevitable and is a reality of construction projects. Most construction contracts include change clauses and allowing contractors an equitable adjustment to the contract price and duration caused by change. However, the actions of a contractor can cause a loss of productivity and furthermore can result in disruption of the whole project because of a cumulative or ripple effect. Because of its complicated nature, it becomes a complex issue to determine the cumulative impact (ripple effect) caused by single or multiple change orders. Furthermore, owners and contractors do not always agree on the adjusted contract price for the cumulative Impact of the changes. A number of studies have attempted to quantify the impact of change orders on project costs and schedule. Many of these attempted to develop regression models to quantify the loss. However, regression analysis has shortcomings in dealing with many qualitative or noisy input data. This study develops ANN models to classify and quantify the labor productivity losses that are caused by the cumulative impact of change orders. The results skew that ANN models give significantly improved performance compared to traditional statistical models.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.4 no.5
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• pp.27-42
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• 1981

The object of this paper is to Study the work measurement which is one of the principal technique in work study for the improvement of Productivity in the foundry industry. Most of domestic mechanical enterprise using the expensive foreign machinerise is inoufficient for the standardization of the operation method and time. Therefore, the improvement of operation and productivity through the introduction of the work measurement is an urgent task. Therefore, this paper is contribute to the improvement of operation and to reduce the loss time through the application of the work measurement based on the case study conducted at W-Foundry Corporation. The summary of this study is follows; 1. The measurement of operation efficiency can be accomplished by the standard time. 2. The detailed causes and counter-proposal of loss time can be established, 3. More than 50% of loss time is attributed to c/p.

• Design & Manufacturing
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• v.6 no.1
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• pp.18-23
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• 2012

HI-WORTH T-32, a non-powered plasma cutter, is a portable cutter that utilizes compressor-plasma inverter. With a special air-pressure piston, the cutter is semiautomatic. When they were produced by die casting dies, the bodies or housings of the cutter have defects about 100 percent of defect rate due to blisters and thermal deformation. Therefore, they are produced by mechanical machining, which leads to a hike in material and machining costs and to the loss of productivity. And companies are left with insignificant profit margins. Besides mechanical machining, this study proposes to modify defective mold and cut down defective rate and boost productivity.

• The Journal of Fisheries Business Administration
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• v.36 no.1 s.67
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• pp.1-26
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• 2005

This study attempts to suggest the requisites for selecting the neighboring fisheries of the same kind related to the calculation of aquaculture fisheries loss stipulated in the article 62 of enforcement ordinance of fisheries law. First of all, the requisites for the same kind of aquaculture fisheries are legally evident. The more important requisites are the factors for the neighboring fisheries of aquaculture fisheries. Here the factors we must consider are the same oceanic environment, the same fisheries management, and the same productivity of fisherman. In conclusion, the best way of selecting neighboring fisheries is picking up the adjacent fishery to the fishery because the factor of the same oceanic environment is the most important in determining the productivity of fisheries.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.556-562
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• 2012

Micro electrical discharge machining (${\mu}EDM$) has been used for non-conventional material removal. One drawback of ${\mu}EDM$ is low productivity. In this study, we tried to find the optimal machining conditions to manufacture the micro hole with an optimal machining time without loss of accuracy. Taguchi method was used to figure out the relation between machining parameters and characteristics of the process. It was found that the electrode wear, the entrance and exit clearance gave a significant effect on the diameter of the micro hole when the diameter of the electrode was identical. Grey relational analysis was used to determine the optimal machining condition for minimum machining time without loss of accuracy. The obtained optimal machining condition was the input voltage of 80V, the capacitance of 680pF, the resistance of $500{\Omega}$, the feed rate of $1.5{\mu}m$/s and the spindle speed of 2900rpm. The machining time was reduced to 48% without loss of accuracy under the optimal machining condition.

• Journal of the Korea Institute of Building Construction
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• v.13 no.4
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• pp.372-381
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• 2013

In the construction industry, a great deal of research has been focused on productivity improvement because a minor change in labor productivity can often make the difference between a profit and a loss. This study shows how productivity measurement methods can be applied in practice, step by step, to analyze and identify potential problems both in productivity and methods performance for masonry work. A work sampling technique was conducted to determine the nature and extent of an observable activity as an aid to measuring overall performance. Also, a method productivity delay model was used to identify non-productivity in individual cycle times. From the work sampling technique, it was found that the masonry crew had a Labor Utilization Factor of 47.1%, and from the videotape analysis, it was found that the material and dumpster location need to be adjusted to reduce the travelling distance. We have found that efforts to improve the productivity of masonry work should be focused almost exclusively on machine and labor delays, based on the result from the method productivity delay model.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.557-562
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• 2002

Physiological characteristics such as specific productivity, morphology of Streptomyces cells Immobilized on celite beads, and operational stability at different dilution rates were investigated in continuous immobilized-cell cultures for the production of kasugamycin. At a dilution rate (D) of 0.05 $h^{-1}$, a relatively high specific productivity was attained and the loss of cell-loaded beads was negligible. At D=0.1 $h^{-1}$, a higher specific productivity and cell concentration could be obtained, resulting in a significantly improved volumetric kasugamycin productivity. However, no stable operation could be maintained due to a significant loss of cell-loaded beads from the reactor that was caused by their fluffy morphology developed in the later stage. At D=0.2 $h^{-1}$, the production of kasugamycin and cell growth were observed to be severely inhibited by the high concentration of residual maltose.

• Proceedings of the Safety Management and Science Conference
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• 2005.11a
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• pp.199-202
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• 2005

All machines and systems in a firm should be managed for optimizing its productivity. Actually, however, it is hard to manage the machines of a firm in collective methods because the company making each machine varies and the way maintaining each machine is various. As a machine Is out of order, the machine is fixed by the repair person from the company making the machine. Every time comes repair person to fix a machine firm having the machine would experience time loss and cost loss. Therefore, a firm needs to manage blueprint of their machine to reduce loss in time and cost and to maintain their facilities in TPM(Total Productive Management) to make operators manage directly. In this study, we suggest the method to manage a blueprint of a machine with TPM.

• Journal of Preventive Medicine and Public Health
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• v.39 no.1
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• pp.21-29
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• 2006

Objectives: We wanted to estimate the annual socioeconomic costs of alcohol drinking in Korea. Methods: The costs were classified as direct costs, indirect costs and the other costs. The direct costs consisted of direct medical costs, indirect medical costs and subsidiary medical costs. Particularly, the medical costs and population attributable fraction for disease were considered to reflect the calculation of the direct medical costs. The indirect costs were computed by the extent to which the loss of productivity and loss of the workforce might have occurred due to changes in mortality and morbidity according to alcohol drinking. The other costs consisted of property loss, administration costs and costs of alcoholic beverage. Results: The annual costs, which seemed to be attributable to alcohol drinking, were estimated to be 149,352 hundred million won (2.86% of GDP). In case of the latter, the amount includes 9,091 hundred million won for direct costs (6.09%), 62,845 hundred million won for the reduction and loss of productivity (42.08%), 44,691 hundred million won for loss of the workforce (29.92%), and the other costs (21.91%). Conclusions: Our study confirms that compared with the cases of Japan (1.9% of GNP) and the other advanced countries (1.00-1.42% of GDP), alcohol drinking incurs substantial socioeconomic costs to the Korean society. Therefore, this study provides strong support for government interventions to control alcohol drinking in Korea.