• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.383-385
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• 2010

This study analyzed the change of flowout and suspend solid in Andong and Imha basin according to the climate change to develop evaluation index about turbid water occurrence possibility and to support the countermeasures for turbid water management using GIS-based Soil and Water Assessment Tools (SWAT). MIROC3.2 hires model values of A1B climate change scenario that were supplied by Intergovernmental Panel on Climate Change (IPCC) were applied to future climage change data. Precipitation and temperature were corrected by applying the output value of 20th Century Climate Coupled Model (20C3M) based on past climate data during 1977 and 2006 and downscaled with Change Factor (CF) method. And future climate change scenarios were classified as three periods (2020s, 2050s, 2080s) and the change of flowout and suspended solid according to the climate change were estimated by coupling modeled value with SWAT model.

• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.122-127
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• 2011

A general analysis of an aperture-coupled vertically mounted strip antenna is presented to examine its circuit characteristics. Based on the present analysis, an equivalent circuit model is developed, and an analytic or semi-analytic evaluation of the related circuit element values is described. The effects of structure parameters on the antenna characteristics were studied with the developed equivalent circuit, and the design curves were obtained. To check the validity of the proposed analysis and design theory, two C-band antennas (5.0 GHz and 4.5 GHz) were designed and fabricated. Their computed characteristics, derived from the proposed network analysis, were compared with the measurement and simulation results. The error of the current model in predicting the operating center frequency was less than 0.50 %. In addition, the observed bandwidth was found to be comparable to the conventional microstrip antennas. All the results fully validated the efficiency and accuracy of the proposed analysis and network model.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.226-232
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• 2000

The design of agricultural facilities is the consistent activities, which systematically analyze all the actual conditions, design the unit structures, and improve the faming environment through efficient organization of the unit facility. The design of agricultural facilities is composed of site study, preliminary design, primary design, and detail design. Integrated design system can manage and process the information created by and used in all steps of design process. Formal data models of these design activities are important conceptual steps in development of integrated design system. However, most of existing models are not available for agricultural facilities. To support efficiently developing the integrated design system of agricultural facilities, we have developed the Multi-Layered Primitive-Composite mode I through object-oriented analysis of agricultural facilities. The MPC model not only satisfies the characteristics of agricultural facility, such as variety, coupling, informal data, but also improves abilities of integrated design system such as extensibility, flexibility, and granularity. The paper presents a formal definition of the MPC model.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.182-185
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• 2003

We have suggested an equivalent circuit model for switching performance of bipolar spin transistor composed of a nonmagnetic metal film (N) sandwiched between two ferromagnetic metal films (F1 and F2). The 'ON' or 'OFF' operation of this equivalent circuit model is simulated by depending on the orientation of the magnetization of F1 and F2 rather than the strength of the external magnetic filed. Changing the coupling coefficient, turn number of two inductances, (L1:L2) like a transformer, and parallel variable resistance R4 connected to L2 at the collector region, we can explain the magnetic characteristics and the dependence of magneto resistance ratio on the orientation of spin-polarized electrons.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.489-496
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• 2002

The lateral buckling of a laminated composite beam is studied. A general analytical model applicable to the lateral buckling of a composite beam subjected to various types of loadings is derived. This model is based on the classical lamination theory, and accounts for the material coupling for arbitrary laminate stacking sequence configuration and various boundary conditions. The effects of the location of applied loading on the buckling capacity are also included in the analysis. A displace-based one-dimensional finite element model is developed to predict critical loads and corresponding buckling modes for a thin-walled composite beam with arbitrary boundary conditions. Numerical results are obtained for thin-walled composites under central point load, uniformly distributed load, and pure bending with angle-ply and laminates. The effects of fiber orientation location of applied load, and types of loads on the critical buckling loads are parametrically studied.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.799-806
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• 1989

Component mode synthesis (CMS) method can be divided into free, fixed and hybrid interface method according to each component's connecting conditions. In this paper, major mode synthesis methods were reviewed and their accuracies were examined by comparing the calculated eigenvalues with those from full finite element (FE) model. Also, CMS is expanded into the coupling between finite element (FE) and experimental model. Since the assumed experimental data seldom have slope information, the slope information at the interface points is prepared by curve-fitting of the calculated values. A simple beam structure to show the effectiveness of the above method, and we found that it can improve the accuracy of the synthesis method in calculation, expecially in the low modes.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.6
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• pp.470-476
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• 1989

In order to develop a mathematical model which can predict the operating voltage and current of a discharge lamp, the properties and the physical phenomena of a low pressure gas discharge are investigated. Fluorescent lamp which uses a low pressure mercury-argon gas discharge is used in the model development. In a low pressure mercur-argon gas discharge, the continuity equation for each excited atom and electron, and the electron energy balance equation can predict the physical quantities of discharge. By coupling these equations and the circuit equation, the electrical characteristics of the discharge lamp can be predicted. To verify the validity of the suggested model, we calculated the voltage and current of a fluorescent lamp operating with inductor ballast for source frequency of 5KHz, 8KHz, 10KHz, and 13KHz. The results show good agreements in wave forms between the measured voltage and current, and the difference between the measured and calculated one is less than 5%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.714-719
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• 2000

The analysis of structures may be classified into three categories: theoretical, numerical, and experimental approaches. The numerical and experimental methods are very useful when the structures to be analyzed have complicated shapes or geometry because theoretical methods are restricted to simple and special cases. However, the theoretical methods are very important analysis in the viewpoint that they can give basic insight for the structural behavior. Among them the modal model method is widely used because of the powerful propertiy of eigenfunctions(mode shapes), or orthogonality. In this paper, the modal model method was reviewed and studied for various models for structures: string, beam, membrane, and plate. Governing equations and solution methods were compared and a structural-acoustic coupling system was used for an application.

• Journal of Ocean Engineering and Technology
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• v.22 no.1
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• pp.1-5
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• 2008

A 2-D Fluent-based numerical wave tank(FBNWT) capable of simulating wave propagating and overtopping is presented. The FBNWT model is based on the Reynolds averaged Naiver-Stokes equations and VOF free surface tracking method. The piston wave maker system is realized by dynamic mesh technology(DMT) and user defined function(UDF). The non-iteration time advancement(NITA) PISO algorithm is employed for the velocity and pressure coupling. The FBNWT numerical solutions of linear wave propagation have been validated by analytical solutions. Several overtopping problems are simulated and the prediction results show good agreements with the experimental data, which demonstrates that the present model can be utilized in the corresponding analysis.

• Advances in aircraft and spacecraft science
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• v.4 no.2
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• pp.185-202
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• 2017

In a flexible airvehicle, an assessment of the structural coupling levels through analysis and experiments provides structural data for the design of notch filters which are generally utilized in the flight control system to attenuate the flexible response pickup. This is necessitated as during flight, closed loop control actuation driven with flexible response inputs could lead to stability and performance related problems. In the present work, critical parameters influencing servoelastic response have been identified. A sensitivity study has been carried out to assess the extent of influence of each parameter. A multi-parameter tuning approach has been implemented to achieve an enhanced analytical model for improved predictions of aircraft servoelastic response. To illustrate the model updation approach, initial and improved test analysis correlation of lateral servoelastic responses for a generic flexible airvehicle are presented.