• International conference on construction engineering and project management
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• 2013.01a
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• pp.300-303
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• 2013

On BIPV systems, especially roof-top PV systems, the power generation is easier to be reduced due to the shades of facilities nearby, or roof itself. To secure profitability of roof-top PV systems, the optimal design of solar arrays through the precise shading analysis is an important item of design considerations. In this paper, an optimization system for array design of roof-top PVs is to be developed using three-dimensional Geospatial Information System(GIS). The profitability of income and expense is considered through the shading analysis of entire roofs. By applying the system to project for validation, the adequacy and the improvement of NPV of the system were verified compared to expert's design. The system has significance by reason that PV modules are placed through rules established with expert knowledge and geometric rules were applied to reflect the constructability and maintainability.

• Nuclear Engineering and Technology
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• v.29 no.1
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• pp.78-84
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• 1997

The specific purpose of this study is to develop the numerical guide for the cost-benefit analysis of ORE ($/person-Sv reduction) to meet the criterion of ALARA in the design stage of the KNGR. In deriving the guide, the risk factor which is defined by the risk to unit collective radiation exposure dose (deaths/person-Sv) and the monetary value of human life ($/death) are required. The risk factor has been estimated from various clinical data accumulated for a number of years and continuously modified. And the monetary value of human life is usually quantified using the human capital approach. In this study, the risk to radiation exposure perceived by a group of people is investigated through an extensive poll survey conducted among university students in order to modify the existing risk factor for radiation exposure. And in evaluating the monetary value of human life, the QOL factor is introduced in order to incorporate the degree of public welfare or quality of life. As a result of study, a value within the range of 151, 000~172, 000 dollars per person-Sv reduction is recommended as the appropriate interim numerical guide for cost-benefit analysis of ORE to meet the criterion of ALARA in the design stage of the KNGR. A poll survey was also conducted in order to see whether the public acceptance cost of nuclear power should be incorporated in developing the guide, and the result of study shooed that such a cost does not need to be considered.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.4
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• pp.229-237
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• 2022

The sewer capacity design have been based on the Huff model or the rational equation in South Korea and often failed to determine optimal capacity, resulting in frequent urban flooding or over-sizing. A time distribution of rainfall (i.e., Huff or ABM method) could be used instead of a rainfall hyetograph obtained from statistical analysis of previous rainfalls. In this study, the Huff method and the ABM method, which predict the time distribution of rain intensity, which are widely used to calculate sewage pipe drainage capacity using the SWMM, were compared with the standard rainfall intensity hyetograph of Seoul. If the rainfall duration was 30 minutes to 180 minutes, the rainfall intensity value calculated by the Huff model tended to be less than the rainfall intensity value of the standard rainfall intensity in the initial 5-10 minutes. As a result, more than 10% to 30% of under-design would be made. In addition, the rainfall intensity value calculated by the Huff model from the section excluding the initial 5-10 minutes of rainfall to the rainfall duration was calculated larger than the value using the standard rainfall intensity equation, which would result in an over-design of 10% to 30%. In the case of a relatively long rainfall duration of 360 minutes (6 hours) to 1,440 minutes (24 hours), it showed an lower rainfall intensity of 60 to 90% in the early stages of rainfall, but the problem of under-design had been solved as the rainfall duration time had elapsed. On the other hand, in the alternating block method (ABM) method, it was found that the rainfall intensity at the entire period at each assumed rainfall duration accurately matched the standard rainfall intensity hyetograph of Seoul.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.1
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• pp.63-69
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• 2015

In this paper, infrared reflector design targeting infrared stealth effect is presented using structural optimization based on the phase field method. The analysis model was determined to accomplish the design that an incident infrared wave was reflected to a desired direction. The design process was to maximize the objective value at the measuring domain located in a target region and the design objective was set to the Poynting vector value which represents the energy flux. Optimization results were obtained according to the variation of some parameter values related to the phase field method. The model with a maximum objective value was selected as the final optimal model. The optimal model was modified to eliminate the gray scale using the cut-off method and it confirmed improved performance. In addition, to check the desired effect in the middle wave infrared range(MWIR), the analysis was performed by changing the input wavelength. The finite element analysis and optimization process were performed by using the commercial package COMSOL combined with the Matlab programming.

• Journal of the Korean Society of Systems Engineering
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• v.13 no.1
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• pp.25-31
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• 2017

This paper aims to evaluate the conservatism in the design of APR1400 (Advanced Pressurized water Reactor 1400 designed by KHNP) reactor internals component, the LSS (Lower Support Structure). Re-engineering of the LSS is done based on the system design condition data and applicable ASME code that was used for the original APR1400 design. Systems engineering approach is applied to design the LSS of APR1400 without refering APR1400 LSS dimensional parameters and tries to verify important design parameters of APR1400 LSS as well as the validity of the re-engineering design process as independent verification method of reactor component design. Systems engineering approach applied in this study following V-model approach. The re-engineered LSS design showed more than enough conservatism for static loading case. The maximum deflection of LSS is under 1mm (calculated value is 0.25mm) from 4000 mm diameter of LSS. Hence the deflection can be ignored in other reactor internals for structural integrity assessment. Especially the effect of LSS deflection on fuel assembly can be minimized and which is one of the main requirements of LSS design. It also showed that the maximum stress intensity is 2.36MPa for the allowable stress intensity of 60.1 MPa. The stress resulted from the static load is also very small compared to the maximum allowable stress intensity, hence there is more than enough conservatism in the LSS design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.497-503
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• 2016

In this study, we formulate an acoustical topology optimization problem to optimally design a partition layout inside the expansion chamber of a muffler. The lower-limit insertion loss value at a target frequency is constrained, and the partition volume is selected as an object function. In this study, we calculate the insertion loss outside the duct, while to determine the noise-attenuation performance, we use the insertion loss value calculated inside the duct or transmission loss value obtained in a previous study. We employ the finite-element model for acoustical analysis, and we determine the transmission of an incident acoustic wave through each finite element using the functions of design variables that change continuously between "0" and "1." The rigid body elements, which totally reflect incident waves, build up partitions. Finally, we compare optimal topologies that depend on the target frequency and the allowed lower-limit value of insertion loss.

• Journal of Engineering Education Research
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• v.15 no.5
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• pp.25-30
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• 2012

"The engineering education program for environmental intention and value creation" has been executed from 2008 to 2010 in Suzuka National College of Technology, which program was promoted as "Good Practice for Education" by Ministry of Education, Culture, Sports, Science and Technology Japan. "Eco-car project" is one of these practical ecology/environment education programs. The project's members have been learning and researching the environmental managements by the process of design, manufacturing, and assembly of solar car, highly effective fuel consumption car (Eco-run car), electric vehicle and fuel-cell car. Also this project was supported by some professional experts of the local industries and community. The students learned the actual industrial technique, the engineering management and the structure of local industries by this project. In this paper, the environmental intention engineering design education with local industry collaboration is introduced.

• Korean Journal of Construction Engineering and Management
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• v.6 no.6 s.28
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• pp.133-141
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• 2005

In the resent years, the importance of VE (value engineering) and LCC (life cycle cost) analysis for apartment building construction projects has been fully recognized. Accordingly theoretical models, guidelines, and supporting software systems were developed for the value engineering and life cycle cost analysis for construction management including large building systems. However, the level of consensus on VE and LCC analysis results is still low due to the lack of reliable data on maintenance. This paper presents time dependent LCC model based value analysis method for rational investment decision making and design alternative selection for construction of apartment building. The proposed method incorporates a time dependent LCC model and a performance evaluation technique by fuzzy logic theory to properly handle the uncertainties associated with statistics data and to analyze the value of alternatives more rationally. The presented time dependent VE and LCC analysis procedure were applied to a real world project, and this case study is discussed in the paper. The model and the procedure presented in this study can greatly contribute to design value engineering alternative selection, the estimation of the life cycle cost, and the allocation of budget for apartment building construction projects.

• Journal of Engineering Education Research
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• v.15 no.1
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• pp.79-83
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• 2012

I argue that STS education for engineers, despite its prima facie usefulness in demystifying the conventional image of science and technology, should deal with a few challenges in order to cultivate 'responsible' engineers. The challenges come from the fact that there are more than one legitimate way of understanding 'responsible' in the engineering contexts depending on how wide the range of responsibility is intended and on how the relevant reference class is defined. In order to tackle these issues, I suggest that we should take into account more seriously the 'value-laden' nature of the engineering design.

• Wind and Structures
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• v.31 no.3
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• pp.197-207
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• 2020

Knowledge on the design value of extreme wind pressure coefficients (EWPC) of a specific zone of buildings is essential for the wind-resistant capacity of claddings. This paper presents a method to estimate the representative EWPC introducing the multivariate extreme value model. The spatial correlations of the extreme wind pressures at different locations can be consider through the multivariate extreme value. The moving average method is also adopted in this method, so that the measured point pressure can be converted to wind pressure of an area. The proposed method is applied to wind tunnel test results of a large flat roof building. Comparison with existing methods shows that it can give a good estimation for all target zones with different sizes.