• Journal of Korean Society of Transportation
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• v.9 no.2
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• pp.41-56
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• 1991

The aim of this research is designing road lighting installations(arrangement, mounting height spacing and overhang) which produce a certain level and distribution of luminance together with minimal glare. These can be varied over a limited range for a given luminance and road surface to achieve the required installation performance. In Korea there are no code of practice which lays down recommended performance criteria (Lavg, Uo, Ul, G, TI) with practical design guidance on how to achieve them. In case study design rules and current installation of road lighting in daegu city are analysed. The core of research are suggesting a new performance criteria and providing a set of table giving the maximum lognitudinal spacing between successive luminaires. The result of this research prescribes the combination of height and spacing for various road widths and arrangements which will achieve a specified minimum performance on straigt roads for particular luminaire and a particular road surf-ace.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.343-347
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• 2001

Advanced Pressurized Reactor 1400(APR-1400), which is a standard evolutionary advanced light water reactor(ALWR), has been developed from 1992 as one of long-term Government Project(G-7). The APR-1400 is designed to operate at the rated output of 4000MWt to produce an electric power output of around 1450MWe. The balance of plant (BOP) for the secondary system consists of main steam, feedwater, condensate, turbine generator and auxiliary system. In this paper, we describe the major design features of secondary component, balance of plant configuration, and then the turbine cycle thermal performance evaluation using PEPSE code.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.188-192
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• 2009

A massive cavity is generated behind the underwater vehicles, such as marine propellers, pump impellers, nozzles, injectors, torpedoes, etc. when a underwater vehicle moves at very high speed in the underwater. At this point it makes supercavitating flow and the nose, ie., the cavitator is very important fator at the vehicle since it should be surrounded by the cavity. The present work has focused on the simulation of cavitation flow using the new cavitator. The governing equation is the Navier-Stokes equation based on homogeneous mixture model. For the code validation, the results from the present solver have been compared with experiments and other numerical results. A fairly good agreement with the experimental data and other numerical results have been obtained.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.149-154
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• 2009

The cavitating flow simulation is of practical importance for many engineering systems, such as marine propellers, pump impellers, nozzles, injectors, torpedoes, etc. The present work has focused on the simulation of cavitating flow past cylinders with strong side flow. The governing equation is the Navier-Stokes equation based on homogeneous mixture model. The momentum and energy equation is in the mixture phase while the continuity equation is solved liquid and vapor phase, separately. An implicit dual time and preconditioning method are employed for computational analysis. The results from the present solver have been in a fairly good agreement with the experimental data and other numerical results. After the code validation the strong side flow was applied to include the wake flow effect of the submarine.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.126-130
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• 2000

In this study, flutter characteristics of a composite wing have been studied for the variation of laminate angles in the subsonic, transonic and supersonic flow regime. The laminate angles are selected by the aspect of engineering practice such as 0, $\pm$45 and 90 degrees. To calculate the unsteady aerodynamics for flutter analysis, the Doublet Lattice Method(DLM) in subsonic flow and the Doublet Point Method(DPM) in supersonic flow are applied in the frequency domain. In transonic flow, transonic small disturbance(TSD) code is used to calculate the nonlinear unsteady aerodynamics in the time domain. Aeroelastic governing equation has been solved by v-g method in the frequency domain and also by Coupled Time-Integration Method(CTIM) in the time domain. from the results of present study, characteristics of free vibration responses and aeroelastic instabilities of a composite wing are presented for the set of various lamination angles in the all flow range.

• Journal of computational fluids engineering
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• v.8 no.3
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• pp.50-55
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• 2003

Recent numerical simulation has a tendency to require the higher-order accuracy in time, as well as in space. This tendency is more true in LES and acoustic noise simulation. In the present work, the accuracy of a Fractional step method, which is widely used in LES simulation, has been increased to the fourth-order accurate compact Pade discretization. To validate the present code, the flow-field past a cylinder was simulated and compared with experiment. A good agreement with experiment was achieved.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.3
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• pp.75-81
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• 2003

Pocket machining is metal removal operation commonly used for creating depressions in machined parts. Numerically controlled milling is the primary means for machining complex die surface. These complex surfaces are generated by a milling cutter which removes material as it traces out pre-specified tool paths. To machine, a component on a CNC machine, part programs which define the cutting tool path are needed. This tool path is usually planned from CAD, and converted to a CAM machine input format. In this paper I proposed a new method for generating NC tool paths. This method generates automatically NC tool paths with dynamic elimination of machining errors in 2$\frac{1}{2}$ arbitrary shaped pockets. This paper generates a spiral-like tool path by dynamic computing optimal pocket of the pocket boundary contour based on the type and size of the milling cutter, the geometry of the pocket contour and surface finish tolerance requirements. This part programming system is PC based and simultaneously generates a G-code file.

• Asia pacific journal of information systems
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• v.7 no.2
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• pp.77-102
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• 1997

The use of statistical methods in the MIS research is increasing. However, there has been a meager attempt to critically evaluate the use statistical methods in MIS research papers. The review of 33G papers published in MIS Quarterly from Volume 1 to 14 resulted in three findings; (1) the portion of empirical research has been gradually increasing compared with non-empirical research, (2) univariate parametric statistical methods are most popular among MIS researchers, (3) researchers do not comply with the writing code of scientific research. This paper disscusses what errors MIS researchers might commit in using statistical research methods and how to prevent those errors in each of three stages of research, research design phase, statistical inference phase, and interpretation phase.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.409-412
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• 2004

In this paper, an integrated automation system of pattern design and $CO_2$ laser cutting for diving suits is presented. Pattern design includes grading which creates a full-size range from a base pattern. Tool path for laser cutting from the patterns is generated in G-code format. $CO_2$ Laser cutting machine is developed to help cut the patterns with accuracy and speed. Aluminum profiles, ball screws, and stepping motors are engaged into the machine as frame structure, transfer unit, and driving devices respectively. The developed system is tested in dry suit cutting, convincing it can be readily introduced in driving suits manufacturing with respect to cost and efficiency.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.917-922
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• 2002

This paper deals with the estimation of the maximum crack widths considering bond-slip relationships based on experimental data that were tensed by axial force. It is certificated that the concrete stress condition clearly affects the bond-slip relationship. The proposed method utilizes the conventional crack and bond-slip theories as well as the characteristics of deformed reinforcement and size effects. An analytical equation for the estimation of the maximum flexural crack width is formulated as a function of minimum crack length and the coefficient of bond stress effect. The validity, accuracy and efficiency of the proposed method are established by comparing the analytical results with the experimental data and the major specifications (e.g., ACI, CEB-FIP Model code, Turocode 2, JSCE, etc.). The analytical results presented in this paper indicate that the proposed method can be effectively estimated the maximum flexural crack width of reinforced concrete.