• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1465-1468
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• 2006

Railway is superior to the other land transportation systems in aspects of environmental problems. Environmental problems are not considered during a preliminary feasibility study. Investment for railway is low because of low B/C(benefit/cost)ratio in the economical efficiency analysis during the preliminary feasibility study. The body of this paper studies the railway noise which can reflect environmental problems an assessment of environmental impact. The body of this paper studies the presumption of The Benefit Cost of railroad noise arresting it will be able to reflect the evaluation environmental matter of the effect which it gives to an environment.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.4
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• pp.2063-2077
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• 1970

The Purpose of this study is to give the hydrologically basic data for the development of water resources in Korea and a quantity of daily average precipitation and its frequency in a year are investigated to study the presumption which is affected to river flow. Characteristics of precipitation is poor as source of water resources compared with its efficiency. So, because of such characteristics of precipitation, river flow also is in harmony and distribution of river flow comes to the result of irregularity, that is, range of river coefficiet between the quantity of maximum river flow and others river flow is big, and it is insufficient as source of water resources. Yearly river flow being expressed by daily unit indicates the ratio(%) of distribution to total yearly river flow, and the model of hydrograph is drawn up. The gives the basis to make yearly water balance sheet. This study is not completed, yet but in forth-coming days, the water will try continuously to give more correct basis for the development of water resources according to a great deal of data.

• Journal of Educational Research in Mathematics
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• v.12 no.2
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• pp.275-290
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• 2002

This Study takes Peirce' abduction which is Phenomenology' first reasoning mode, as a part of mathematical reasoning with deduction and induction. Abduction(retroduction, hypothesis, presumption, and originary argument) leads a case through a result and a rule, while deduction leads a result through a rule and a case and induction leads a rule through a case and a result. Polya(1954) involved generalization, specialization, and analogy within induction, but this paper contain analogy in abduction. And metaphors and metonymies are also contained in abduction, in which metaphors are contained in analogy. Metaphors and metonymies are applied to semiosis i.e. the signification of mathematical signs. Semiotic analysis for a student's problem solving showed the semiosis with metaphors and metonimies. Thus, abductions should be regarded as a mathematical reasoning, and we must utilize abductions in mathematical teaming since abductions are thought as a natural reasoning by students.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.164-169
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• 2008

The increasing late-payment rate of credit card customers caused by a recent economic downturn are incurring not only reduced profit of department stores but also significant loss. Under this pressure, the objective of credit forecasting is extended from presumption of good or bad customers to contribution to revenue growth. As a method of managing defaults of department store credit card, this study classifies credit delinquents into some clusters, analyzes repaying patterns of customers in each cluster, and develops credit forecasting system to manage delinquents of department store credit card using data of Korean D department store's delinquents. The model presented by this study uses Kohonen network, a kind of artificial neural network of data mining techniques to cluster credit delinquents into groups. Logistic regression model is also used to predict repayment rate of customers of each cluster per period. The accuracy of presented system for the whole clusters is 92.3%.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.34
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• pp.83-89
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• 1995

We call as plant life cycle the process starting from plant plan, design to disuse by way of construction, operation, but the plant facility inside it comes to changes of cope with various inner factor like blazing phenomenon and outer factor according to economic state. On the presumption of these factors, the problem is brought about how plant should be managed, this study attempt to suggest the conservation management through economic evaluation in investment design and alternative, that is, methodology connecting that of economical efficiency evaluation based on LCC(Life Cycle Costing) thinking method and facility management with that of life prediction.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.395-404
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• 2013

The risk of pipe-bursting in multi-regional transmission mains consisting of 89 % of singled pipeline is so high that pipeline stabilization project is required such as renewal and replacement, pipe paralleling, emergency ties. Pipeline stabilization projects could be postponed at the step of initial decision-making because effect of this project is intangible benefit like activation of economic, improvement of welfare related to water. This study is to suggest quantified economical feasibility model for intangible benefit presumption to solve above problem. Cost reduction of emergency water supply, leakage, burst restore and energy efficiency improvement was altered and applied. As a result of economic analysis taking into account estimated benefit and cost under discount rate 5.5 %, service life 40 years, sufficient economic feasibility analyzed with B/C 2.45, NPV 317,700 million won, IRR 9.09 %.

• Journal of the Korea Society for Simulation
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• v.13 no.2
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• pp.1-12
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• 2004

This paper estimated the arrival angle and electric wave delay time using the space method law and the directions of arrival (DOA) estimation algorithm in case of signal correlation. Space method law is the method used to repress cross correlation before applying the weight value to the receiving signal. The values of the diagonal elements in the correlation matrix were averaged to replace as the diagonal elements value. In the area of wireless communication or mobile communication, there are high correlations in case of low delay time difference in multiple waves. This causes the quality of the communication to drop due to interference with the desired signal elements. This paper estimated the arrival angle and electric wave delay time using the space method law and the MUSIC algorithm. With the arrival angle algorithm, the arrival angle cannot be estimated below 5 in case of signal correlations because the angle resolution capacity decreases accordingly. The super resolution capacity was estimated to determine the arrival angle below 5 in this paper. In addition, the proposed algorithm estimated the short delay time difference to be below 20ns.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.168-176
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• 1997

The purpose of this study is to know load for each human body's knee joint to endure load efficiently, when weight lifter pulls suitable bar in the each weight lifting level. To use the difference of load and correlation between men and women, the conclusion of this stduy is to find parameters to conduct maximum limitation of maximum load to search maximum limitation. The moment of each joint in the lower area was to have a much difference between group of the turunk in the first step. It decreased rapidly until decent and greatly pulled in the second step. Neuromusclar moment increased suddenly in the decrease phase. This phenomenon resulted from shock-absorbing function to sbsorb a load from bar.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.5
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• pp.46-52
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• 2003

End-milling have been used widely in industrial system because it is effective to a material manufacturing with various shape. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in precision machine part and electronic part. The optimum surface roughness has an effect on end-milling condition such as, cutting direction spindle speed, feed rate and depth of cut, etc. Therefore this study was carried out to presume for mutual relation of end-milling condition to get the optimum surface roughness by regression analysis. The results shown that coefficient of determination($\textrm{R}^2$) of regression equation has a fine reliability of 87.5% and regression equation of surface rough is made by regression analysis.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.29-33
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• 2002

There are a lot of errors and little accuracy when calculating the grounding resistance with the transposition methods in the equivalent surface of hemisphere electrode. Therefore we should calculate the grounding resistance by using the mesh factor, In this paper, we would estimate the grounding value of mesh electrode with water tank model & estimation method using the reduced scale ratio of mesh electrode based on the theory of model electrode & proportional factor according to the reduced scale ratio. And also we have confirmed the accuracy of the empirical formula of model electrode by using the regression analysis.