• Journal of Korean Society for Quality Management
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• v.39 no.1
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• pp.71-77
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• 2011

In the fields of reliability application, the most commonly used test methods for reliability qualification are zero failure tests since they require fewer test samples and less test time compared to other test methods that guarantee the same reliability with a given confidence level. An economic zero failure test plan is developed that minimizes the total cost related to perform a life test to guarantee a specified reliability of a product with a given confidence level and a numerical example is provided to illustrate the use of the proposed test method.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1163-1164
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• 2008

From the complexities and functional/operational expectations, the compositions of PC devices requires Device Drivers to deliver full performance of the Hardware. However, due to quick transition of hardwares and expectations of better performance of the system. As a rest users are exposed of unexpected failures of device drivers which will cause malfunction of the system which consequently cause damages in quantity as well as quality wise. In this paper, the method of calculation and/or forecast to unexpected failure will be suggested. It may not be the answer but can be a guide to calculation to economic damage due to device driver failure.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.640-643
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• 1987

A probabilistic production costing model based on the economic load dispatch has been developed. Objective function is composed of fuel cost which is a function of generation output and the failure cost. Coefficients of the failure cost is determined from the known equivalent generation cost. The model is compared with other existing methodolgies and the excellent results are obtained.

• Journal of Applied Reliability
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• v.12 no.1
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• pp.47-56
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• 2012

Reliability demonstration tests with zero-failure acceptance criterion are most commonly used in the field of reliability application since they require fewer test samples and less test time compared to other test methods that guarantee the same reliability with a given confidence level. For products with lognormal lifetime distribution, an economic zero-failure test plan is developed that minimizes the total cost related to perform a life test to guarantee a specified reliability of a product with a given confidence level. A numerical example is provided to illustrate the use of the proposed test plan.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.1
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• pp.37-45
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• 2018

This study develops a model to estimate the economic life of the large-diameter water supply pipeline in Korea by supplementing existing methods used to perform similar calculations. To evaluate the developed methodology, the model was applied to the actual target area with the conveyance pipe in P waterworks. The application yielded an economic life computation of 39.7 years, considering the cost of damages, maintenance, and renewal of the pipeline. Based on a sensitivity analysis of the derived results, the most important factor influencing the economic life expectancy was the predicted failure rate. The methodology for estimating the economic life of the water supply pipeline proposed in this study is one of the core processes of basic waterworks facility management planning. Therefore, the methods and results proposed in this study may be applied to asset management planning for water service providers.

• Environmental Engineering Research
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• v.24 no.1
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• pp.63-73
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• 2019

This study suggests a method for calculating the benefits of water pipe renewal based on an estimate of the water supply suspension risk. The proposed method based on five benefit items is more direct and specific than other benefit estimation methods. In addition, a methodology evaluating the economics of pipe renewal based on pipe failure rate is proposed for estimating the optimal renewal point from an economic perspective. By estimating the optimal renewal period based on a yearly benefit cost ratio per pipe in a case study area, it was possible to draft an optimal renewal plan for the subject region from an economic perspective. Compared with other methodologies, a reasonable optimal renewal period was derived from an economic point of view. The result of this study may be used to develop future water pipe renewal plans. Moreover, the proposed methodologies and results derived from this study can be applied to asset management plans.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.39
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• pp.285-292
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• 1996

In the case of existence of second-hand market, some methods for economic depreciation measurement have been developed. Among them, we consider two method. Those are Box -Cox model by Halten and Wykoff and Ratio method of T-factor by Iowa State University. Here, we suggest a new measurement method of economic depreciation based on the above two methods. According to the new method, we can get the failure rate of a equipment under the appropriate assumption. Then we can measure the economic depreciation more simply.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.2
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• pp.128-135
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• 2000

This paper considers a consecutive k-out-of-n:F system when the failure of a component in the system induces higher failure rate of the preceding survivor. The reliability, mean time to failure(MTTF), and average failure number of a consecutive k-out-of-n:F system are obtained, when the failure of a component increases the failure rate of the survivor which is working just before the failed component. Then the optimal number of consecutive failed components to minimize this long run average cost rate can be obtained. An example is considered to calculate the reliability, MTTF and average failure number of the system. And two procedures that find the optimal number of consecutive failed components are studied. Then, various cases of system parameters are also studied.

• Economic and Environmental Geology
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• v.34 no.6
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• pp.601-615
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• 2001

The study area. Boeun-eup Boeun-kun, belongs to Ogchon metamorphic belt which is highly metamorphosed and consisted of complex geologic formations. Even though the geological structures and formations are complex and metamorphosed, the geological investigation and consideration are not enough and consequently the plane failure is occurred in the rock slope which was under construction on 1 : 0.5 gradient. This area is assessed as unstable and additional failure is possible by the discontinuity with same direction of failure surface. Therefore, the authors evaluate the slope stability using various analysis methods such as SMR, stereographic projection method, and the limit equilibrium analysis. In order to analyze stress redistribution and nonlinear displacement behavior caused by stress release, the authors conduct numerical analysis with UDEC and then the behavior of rock mass is analyzed after reinforcements are applied.

• Journal of environmental and Sanitary engineering
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• v.8 no.2
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• pp.49-64
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• 1993

The present waste problems require a change of thinking with regard to conventional economics. It has been generally believed that competitive markets maximize social welfare. But, the other hand, a few economists argue that "the competitive markets cannot always be relied on to provide all goods in the efficient amount." One of the best examples of the latter contention is the environmental problem. What is the basic thinking of the conventional economics that causes this problems \ulcorner What is the present problem that requires the change of conventional economic thinking \ulcorner The environmental problem result from the conventional economic thinking such as pursuing the limitless of the Gross National Product(GNP), believing the increasing returns in economics of scale and the efficiency of competitive market. This economic principles, howe- ver, does not apply currently to public goods, especially environmental amenity and natural resource because the price of markets does not reflect the natural goods of services. We call this eternality. Externalizes are no considered by either buyers or sellers of goods of which production or use results in an eternality. This leads to market failure are causes an waste problem in the economic activities. Today, it is almost impossible to say in a word what the solution for waste problems is because they are by-products complicated and entangled human activities. In this paper, I have introduced the causes of environmental problems only from the economic point of view. I have also described the needs of conversion of conventional economic thinking. Firstly, sustainable development, maintaining the natural resources, should be the basis of the economic growth rather that pursuing the limitless growth of GNP. Secondly, an appropriate scale of human's production activity should be taken into account to reduce the impact to the natural environment. Thirdly, internalization of eternality is asked to correct the market failure. This requires the public policy such as imposing a talsubsidy, assigning a property right or implement a more detailed environmental quality standard through, because use of the natural resources can be. allocated optimally by the intervention of government or social associations.