• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.794-801
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• 2006

The linkage framework of geometric modeling and analysis based on the NURBS technology is developed in this study. The NURBS surfaces are generated by interpolating the given set of data points or by extracting the necessary information to construct the NURBS surface from the IGES format file which is generated by the commercial CAD systems in the present study. Numerical examples shows the rate of displacement convergence according to the paramterization methods of the NURBS surface. NURBS can generate quadric surfaces in an exact manner. It is the one of the advantages of the NURBS. A trimmed NURBS surface that is often encountered in the modeling process of the CAD systems is also presented in the present study. The performance of the developed geometrically exact shell element integrated with the exact geometric representations by the NURBS equation is compared to those of the previous reported FE shell elements in the selected benchmark problems.

• Journal of the Korean Solar Energy Society
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• v.29 no.5
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• pp.1-7
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• 2009

Energy demands for offices in Korea are surveyed and analyzed to generate communicational models for simulations. Daily energy loads of 13 office buildings scattered in the 6 largest cities in the country are surveyed and analyzed based on energy consumption log sheets. Detailed hourly loads that are frequently required when a detailed operation simulation is performed are measured using remote data acquisition processes for 3 offices. The complete load demand models of electricity, cooling, heating and hot water are established by combining the daily and hourly patterns based on the statistical behavior of the hourly patterns.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.412-418
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• 2006

In this paper we deal with the APARP theory which has been applied for UK railway system and risk assessment method which has been using in the domestic railway system for the safety demonstration. Both techniques are applied to the ATP wayside equipment for interface. Also, fur the applications of each techniques a analysis of the safety activity and a possibility of the application of ALARP theory are evaluated. Finally, we generate requirements of the safety demonstration for the future domestic railway system by way of the analysis of some assumptions and requirement data which can be applied to the risk assessment of ALARP.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.37
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• pp.31-40
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• 1996

The amount of safety stock is decided from various information such as the forecasted demand, the lead time, the size of the order quantity and the desired service level. There are two cases to consider the problem of setting safety stock when both the demand in a period and the lead time are characterized as random variables: the first case is the parameters of the demand and lead time distributions are known, the second case is they are unknown and must be estimated. The objective of this study is to present the procedure for setting safety stocks in the case the parameters of the demand and lead time distributions are unknown and must be estimated. In this study, a simple exponential smoothing model is used. to generate the estimates of demand in each period and a discrete distribution of the lead time is developed from historical data, and the optimal service level is used which determined to consider both of a backorder and lost sale.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.61-66
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• 1996

High pressure. high temperature steam/water blowdown test loop has been constructed. The loop simulates a pressurizer. depressurizalion system and In-Containment Refueling Water Storage Tank (IRWST) with full pressure and temperature conditions. and will be used to generate data for development of an optimal sparser as well as for design of safety/automatic depressurization system. In addition. experiments for reactor safety and pressurizer thermal hydraulics are scheduled. In this paper. general description of the Blowdown and Condensation (B&C) Loop will be given together with the test program.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.831-839
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• 2016

Seismic qualification by test is widely used as a way to show the integrity and functionality of equipment that is related to the overall safety of nuclear power plants. Another means of seismic qualification is by direct integration analysis. Both approaches require a series of time histories as an input. However, in most cases, the possibility of using real earthquake data is limited. Thus, artificial time histories are widely used instead. In many cases, however, response spectra are given. Thus, most of the artificial time histories are generated from the given response spectra. Obtaining the response spectrum from a given time history is straightforward. However, the procedure for generating artificial time histories from a given response spectrum is difficult and complex to understand. Thus, this paper presents a simple time-domain method for generating a time history from a given response spectrum; the method was shown to satisfy conditions derived from nuclear regulatory guidance.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.190-199
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• 2006

A new approach which combines implicit surface scheme and recursive subdivision method is suggested in order to fill the holes with complex shapes in the polygon model. In the method, a base surface is constructed by creating smooth implicit surface from the points selected in the neighborhood of holes. In order to assure C$^1$ continuity between the newly generated surface and the original polygon model, offset points of same number as the selected points are used as the augmented constraint conditions in the calculation of implicit surface. In this paper the well-known recursive subdivision method is used in order to generate the triangular net with good quality using the hole boundary curve and generated base implicit surface. An efficient anisotropic smoothing algorithm is introduced to eliminate the unwanted noise data and improve the quality of polygon model. The effectiveness and validity of the proposed method are demonstrated by performing numerical experiments for the various types of holes and polygon model.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.4
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• pp.32-42
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• 1989

An algorithm and its computer program are developed for the computer aided automatic conversion from 2 dimensional (2-D) design drawings to a 3 dimensional used to generate the tool path of NC machine. The algorithm and its computer program developed were applied to several real objects for their feasibility check and showed satisfactory results. As the results of this study, it was proved that a foundation work to prepare the data base for CAD/CAM integ- ration can be established so as to improve the productivity.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.213-220
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• 1997

In this study, a design for a shape of centrifugal pump impeller has been performed using a p.c. under a Windows environment. Interaction between a user and a computer has been easily established using the Visual Basic. In determining an outer diameter of an impeller, steps are divided into two, a basic computational step and a refinment step. In this way user can enter his/her experience at the refinment step and hence can expect to lessen the nonlinear nature inherent to the design. In determining a shape of a side view of an impeller, the Bezier cubic curve has been used, and it can be seen that the Bezier cubic curves are well suited in the shape design under a Windows environment. By simply manipulating the four control points, one can generate various cubic curves among which one is selected. Also, a simple method, which can determine the curved position of an impeller vane, has been developed. These data can be used for final CAD drawings.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.135-140
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• 2006

Numerical computations are made to predict wave loads on a vertical cylinder in an extreme wave. To generate the extreme wave, a frequency-focused unidirectional wave is adopted in three-dimensional numerical wave tank. The mathematical formulation is wide in the scope of the potential theory with fully nonlinear free surface conditions. As a numerical method, finite element method based on variational principle is applied. Comparisons between the present numerical results and the previous computation data. show a good agreement.