• 산업경영시스템학회지
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• 제36권3호
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• pp.1-7
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• 2013

This paper is a case study of reliability assessment with field warranty data of Clutch Master Cylinder (CMC) in hydraulic clutch system. We estimate lifetime distribution using field warranty data which contain much useful information for understanding reliability of the system in the real-world environments. However, the estimated parameters are far from existing reference values, which seems to be caused right censored field warranty data. To modify the parameters, we use the information of the durability test which is performed to verify that the lifetime of the item meets the required level. After that, we can observe that the modified parameters are closer to the existing reference values. This case study shows a possible idea to supplement lack of right censored field warranty data and its applicability.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1807-1816
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• 2020

In this work, a Gaussian Process (Kriging) approach is proposed to provide efficient dose mapping for complex radiation fields using limited number of responses. Given a few response measurements (or simulation data points), the proposed approach can help the analyst in completing a map of the radiation dose field with a 95% confidence interval, efficiently. Two case studies are used to validate the proposed approach. The First case study is based on experimental dose measurements to build the dose map in a radiation field induced by a D-D neutron generator. The second, is a simulation case study where the proposed approach is used to mimic Monte Carlo dose predictions in the radiation field using a limited number of MCNP simulations. Given the low computational cost of constructing Gaussian Process (GP) models, results indicate that the GP model can reasonably map the dose in the radiation field given a limited number of data measurements. Both case studies are performed on the nuclear engineering radiation laboratories at the University of Sharjah.

• 한국안전학회지
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• 제20권2호
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• pp.50-55
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• 2005

This Paper Presents assessment of fuzzy measure Possibility far the electromagnetic field according to voltage fluctuation of the Jechon Area. To cope with substantial electromagnetic analysis, the safety assessment were analyzed the double 154kV T/L, 345kV T/L, Jechon-Ichon Jechon-Youngju, respectively. As the results of case study, in case of 345kV T/L, the electric field value was 11.4927kV/m, magnetic field value was 0.4622G at the Point about 7m away from the line in severest case. Tn assessment of fuzzy measure Possibility for the electromagnetic field, this paper use probability of fuzzy and measure of fuzziness technique.

• 한국환경교육학회지:환경교육
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• 제13권2호
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• pp.91-102
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• 2000

National curriculum for environmental education recommends various teaching-learning methods including survey and discussion of environmental problems, investigation of case studies, experiments, role play, and field-experience learning in addition to the traditional lecture-oriented teaching methods. The field experience learning in environmental education is considered to be a good method to develop environmentally sound attitude and to cultivate environmental sensitivity, but here has been very limited research concerning models for field-experience learning. The aim of this study is to develop a model of the field-experience learning program of environmental education utilizing environmental facilities. In this study a kind of such a basic model was developed and presented. The developed basic model of the field-experience learning was applied to the case utilizing landfill facilities. A specific application of the landfill program to the Bangcheon-ri landfill, in Daegu, was also presented with related teaching materials developed in this studies. And various aspects in the program was discussed.

• 한국도로학회논문집
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• 제16권4호
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• pp.21-33
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• 2014

PURPOSES: The purpose of this study was to break away from the workforce method using cold-mix asphalt mixtures and has a constant quality and has develop repair materials of pre-production asphalt-precast types. METHODS: The selection of the repair material was determined as the results obtained through physical properties of materials and the field applicability. In case of repair materials, values obtained through Marshall stability test & the dynamic stability test & retained stability test as well as the site conditions was considered. In case of adhesive, test results were obtained through examination of the bond strength(tensile, shear) and the field applicability of the adhesive was examined through combined specimens to simulate field applications. RESULTS : According to the results of laboratory tests, in the case of repair materials, Marshall stability and dynamic stability, retained stability of cold-mix reaction type asphalt mixture is the highest. In the case of adhesive, two-component epoxy-urea has a very high bonding strength(tensile, shear) was most excellent. According to the results of field tests, when epoxy-urea was excellent workability. Also, the repair body through actual mock-up test did not occur large deformation and fracture after 12 months. CONCLUSIONS : A suitable repair material is cold-mix reaction type mixture of asphalt-precast, a suitable adhesive is a two-component epoxy-urea.

• Wind and Structures
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• 제30권2호
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• pp.165-180
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• 2020

To determine tornadic wind loads, the wind pressure, forces and moments induced by tornadoes on civil structures have been studied. However, in most previous studies, only the individual building of interest was included in the wind field, which may be suitable to simulate the case where a tornado strikes rural areas. The statistical data has indicated that tornadoes induce more significant fatalities and property loss when they attack densely populated areas. To simulate this case, all buildings in the community of interest should be included in the wind field. However, this has been rarely studied. To bridge this research gap, this study will systematically investigate the influence of a community of buildings on tornadic wind fields by modeling all buildings in the community into the wind field (designated as "the Community case under tornadic winds"). For comparison, the case in which only a single building is included in the tornadic wind field (designated as "the Single-building case under tornadic winds") and the case where a community of buildings are included in the equivalent straight-line wind field (designated as "the Community case under straight-line winds") are also simulated. The results demonstrate that the presence of a number of buildings completely destroys the pattern of regular circular strips in the distribution of tangential velocity and pressure on horizontal planes. Above the roof height, the maximum tangential velocity is lower in the Community case under tornadic winds than that in the Single-building case under tornadic winds because of the higher surface friction in the Community case; below the roof height, greater tangential velocity and pressure are observed in the Community case under tornadic wind fields, and more unfavorable conditions are observed in the Community case under tornadic winds than under the equivalent straight-line winds.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 추계 학술발표회
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• pp.229-240
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• 2006

Most of rock slopes contain a lot of discontinuities which have a specific direction and various characteristics. In general, the collapses of the rock slopes occur when the sliding dip of the discontinuity is higher than the internal friction angle and also smaller than the free-air plane of the slope. If a general slope theory is only considered in the case of field exploration of the slopes, there is a possibility that dangerous slopes might be estimated as stable slopes. We mention problems that can easily fail to notice something in field exploration and propose the alternatives to solve the problems through the case studies.

• 한국안전학회지
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• 제15권4호
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• pp.69-77
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• 2000

This paper presents a study for decision method of human body safety according to power load fluctuation of the Chechon area. To cope with substantial electromagnetics analysis, the safety assessments were analyzed the double 154 [kV] T/L, 345 [kV] T/L, Chechon-Ichon, Chechon-Youngju, respectively. As the results of case study, in case of 345 [kV] T/L, the electric field value was 11.4927 [kV/m], magnetic field value was 0.4622 [G] at the point about 7 [m] away from the line in severest case. The results showed that the membership of a proposition fuzzy '11.4937 [kV/m] is hazardous' is 0.7063 for the severest case in case of 345 [kV] T/L. As the analytic results using the fuzzy qualifier term, the membership in case of very false is 0.0862 and fairly false is 0.5419, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.515-518
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• 2002

In this study, the ellipsoidal cap type magnetic pole structure was proposed for the electro-magnet in B-H curve tracer. From the simulation for the electro-magnet without specimen, the area of effective uniform field(99% range for the central field value) was considerably increased in case of the newly proposed ellipsoidal cap type magnetic pole than that of the conventional simple-inclined cap type magnetic pole. Also, through the simulation for the electro-magnet with permanent magnet specimen(NaFe30), the optimal Positions of the magnetic field measurement sensor(Hall sensor) were found out in each case and the errors were decreased in case of the newly proposed ellipsoidal cap type magnetic pole.

• 조명전기설비학회논문지
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• 제25권6호
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• pp.57-67
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• 2011

Purpose of this study is to find the mitigation method of magnetic field by finite length multi-conductors such as indoor distribution lines and to be applicable to design of the distribution lines. For this purpose, exact formula about the components $B_x$, $B_y$, $B_z$ of magnetic field need in case of straight line-conductor with finite length forward any direction. In this study simple formula of the components were deduced and by using these formula magnetic fields for various models of line-configurations were calculated. And also a calculation method of induced currents in conductive shield was presented and using this method, programing of calculation is relatively easy and calculation time is short. The magnetic field after cancellation by these induced currents was calculated. All of calculations were performed by Matlab 7.0 programs. Through the calculation results it could be obtained followings for the mitigation of magnetic fields. The separation between conductors ought to be smaller than smaller as possible. In case of 3-phase, delta configuration is more effective than flat configuration. In case of 3-phase, unbalanced currents ought to be reduced as possible.. In case of more than two circuits of 3-phase, adequate locations of each phase-conductor such as rotating configuration of 3-phase conductors are more effective. The magnetic shielding effect of the conductive shielding sheet is very high.