• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.623-628
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• 2002

A meshfree formulation for the calculation of energy band structure is presented. The conventional meshfree shape function is modified to handle the periodicity of Bravais lattice, and applied to the calculation of real-space electronic-band structure. Numerical examples include the Kronig-Penney model potential and the empirical pseudopotentials of diamond and zinc-blonde semiconductors. Results demonstrate that the meshfree method be a promising one as a real-space technique for the calculations of diverse physical band structures.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.7
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• pp.14-21
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• 2015

Distribution systems are operated in radial structure, but temporal loop structure could be founded the live load transfer. Main purposes of reconfiguration of distribution network are load balancing, loss minimization and voltage drop maintaining. In the loop structure, huge loop current can be flowed between two substations in case of large voltage angle difference. Protection devices of distribution line can be triped by this huge loop current. So, precise calculation of loop current is very important for secure switching. This paper proposes a novel calculation method of loop current using the voltage angle differences measured at the tie switches. Feasibility of the propose method has been verified by various case studies based on Matlab simulation.

• Journal of KSNVE
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• v.4 no.2
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• pp.155-161
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• 1994

The dynamic behavior of a complex mechanical structure can be identified by dividing the structure into a series of smaller structure, called sub- structure and by studying the dynamic characteristics of these components. Generally, the dynamic characteristics of mechanical structure are strongly affected by the properties of joint parameters. In this paper, to identify the dynamic characteristics of mechanical structure, and experimental identification method in which directrly measured frequency response function(FRF) is used is considered. The method does not use the procedure of complex matrix calculation but use that of real matrix calculation. To confirm this method, computer simulation is performed by using frequency response function mixed with noise, and the experimental study is performed about the simple structure. The dynamic characteristics of joint parameters and identified more accurately than in using the prcedure of complex matrix calculation.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.357-362
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• 2000

Allowable stress design(ASD) method has been widely used to design steel structures such as boiler and heat recovery steam generator(HRSG) of power plant. However, many researchers are recently intrested in road and resistance factor design(LRFD) method which may take the place of ASD. In this work, the weight calculation of steel structure was compared when ASD and LRFD were applied respectively. For the calculation of weight of steel structure, computer program was developed and applied to obtain beam weight. Using this program and GTSTRUDL, structural design program, weight of steel structure is calculated. As a result of weight calculation, maximum 5.4% of weight reduction is achieved among examples of this study by applying LRFD comparing with the result of ASD, and those results quite dependent on the applied load and member classification.

• Korean Journal of Materials Research
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• v.17 no.7
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• pp.358-360
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• 2007

Cobalt subtitution on NiSi is investigated by using an ab-initio calculation. Firstly, a relaxed NiSi structure is calculated and the calculated lattice parameters are compared with experimentally determined lattice parameters. The calculated values are smaller than the experimental values by about 2%. As the calculation is based on 0 K, and the experimental measurement is performed at room temperature, those values are in good agreement. Next, a Co atom substitutes a Ni and Si site, respectively, to evaluate the preferable site between them. Co prefers Ni site to Si site. The calculated total energy also indicates that the Co substitution to Ni site stabilizes the NiSi structure. Therefore, the thermal stability of NiSi with Co addition can be achieved by the structure stabilization of NiSi by Co substitution into Ni site of NiSi.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.1
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• pp.26-32
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• 2000

Design load calculations which depend on the thermal characteristics of the building structure such as the wall, roof, and fenestration provide the basic data for selecting an HVAC system and its equipment. Most of domestic multi-family houses include a high thermal storage layer like massive concrete structure and a floor heating structure. This study is to compare the results of the design heating load between steady state and unsteady state calculation in order to comprehend the thermal storage effect in multi-family houses. The design heating load under the steady state calculation is estimated from 5.4% to 7.8% larger than that under the unsteady state in the typical floor of a multi-family house model. The design heating load considered the safety factors like a orientation and location factor also is 21.4% to 26.5% larger than that by the unsteady state calculation. So, the safety factors for use of the practicing engineer are analyzed as the main factor of a heating plant oversizing.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.450-454
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• 1999

In order to evaluate the integrity of nuclear power plants, J-integral calculation is crucial. For this purpose, finite element method is popularly used to obtain J-integral. However, high cost time consuming preprocess should be performed to design the finite element model of a cracked structure. Also, the J-integral should be verified by alternative method since it may differ depending on the calculation method. The objective of this paper is to develop a three-dimensional elastic-plastic J-integral analysis system which is named as EPAS. The EPAS program consists of an automatic mesh generator for a through-wall crack and a surface crack, a solver based on ABAQUS program, and a J-integral calculation program which provides DI(Domain Integral) and EDI(Equivalent Domain Integral) based J-integral calculation. Using the EPAS program, an optimized finite element model for a cracked structure can be generated and corresponding J-integral can be obtained subsequently.

• Bulletin of the Society of Naval Architects of Korea
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• v.23 no.3
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• pp.27-38
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• 1986

In the recent years, the finite element method has been a leading method in calculating the strength of ship hull structural members. But such a calculation has many difficulties in constructing data, reducing CPU-time and connecting it with optimal design. This paper describes more efficient method for three dimensional strength calculation of the hull structure of oil tanker by using the slope-deflection method, and the computer program based on this method is developed. The results of the calculation by using this method are compared with those by using the SAP4 program based on the finite element method. Some advantages are obtained from the application of the slop-deflection method described in this paper in the calculation of the hull structure oil tanker.

• Journal of KIBIM
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• v.3 no.3
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• pp.9-18
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• 2013

In case of applying the BIM method in the civil engineering of irregularly shaped structure, BIM method began to be introduced in the current building engineering area compared with the expected effects of the relatively high construction productivity has been recognized. In this paper, I have developed quantity calculation algorithms applying it to earthwork and bridge construction, tunnel construction, retaining wall construction, culvert construction and implemented BIM based 3D-BIM Modeling quantity calculation. Structure work in which errors occurred in range between -6.28% ~ 5.17%. Especially, understanding of the problem and improvement of the existing 2D-CAD based of quantity calculation through rock type quantity calculation error in range of -14.36% ~ 13.07% of earthwork quantity calculation. It's benefit and applicability of BIM method in civil engineering. In addition, routine method for quantity of earthwork has the same error tolerance negligible for that of structure work. But, rock type's quantity calculated as the error appears significantly to the reliability of 2D-based volume calculation shows that the problem could be. Through the estimating quantity of earthwork based 3D-BIM, proposed method has better reliability than routine method. BIM, as well as the design, construction, maintenance levels of information when you consider the benefits of integration, the introduction of BIM design in civil engineering and the possibility of applying for the effectiveness was confirmed. In addition, as the beginning phase of information integration, quantity document automation program has been developed for activation of BIM. And automatically enter the program code number, linkage and manual volume calculation program, quantity document automation programs, such as the development is now underway, and step-by-step procedures and methods are presented.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.78-78
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• 2010

The Adsorption structures of phenylalanine on Ge(100) surface have been investigated as a function of coverage using high-resolution photoemission spectroscopy (HRPES) and density functional (DFT) calculation. To converge these experimental and theoretical conclusion, we systematically performed HRCLPES measurements and DFT calculation for various coverage in the adsorption structures of phenylalanine molecules on the Ge(100) surface. In this study, we found two different adsorption structure as a function of coverage in phenylalanine on Ge(100), monitoring three core level spectra (Ge 3d, C 1s, N 1s, and O 1s) using HRPES Through analysis of the binding energies, we confirmed that O-H dissociated and N dative-bonded structure emerges at low coverage (0.10 ML), which is the same to the result of glycine and alanine on Ge(100) system, whereas O-H dissociation structure also appears at higher coverage. Moreover, we observed the shape of phenyl group being included in phenylalanine is changed from flat to tilting structure at final state using DFT calculation. Through the spectral analysis for phenylalanine, we will demonstrate variation of coverage dependent structural change for phenylalanine on Ge(100) surface using experimental (HRPES) and theoretical studies (DFT calculation).