• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.8
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• pp.1284-1288
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• 1990

We proposed the equations which enable us to calculate more easily the far-field radiation characteristics fo linear antennas with arbitarary current distributions. We derived the equations as series forms by approximating the current distribution on antenna as piecewise sinusoidal functions. The solutions of the approximate equations approach the exact values with increasing number of segments, but we have noticed by several examples that only a few number of segments are enough for practical problems.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.1
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• pp.19-24
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• 1992

The analysis of the resonant tunneling based on the exact solution of Schrodinger equations is performed in a single quantum well structure under applied bias. The transmittivity and the net tunneling current density are calculated with Airy function and the boundary conditions which is suggested by Bastard. The results are compared with those from other methods and boundary conditions. From the calculated J-V characteristics for the tunneling current, the dependence of the voltage location showing the first peak current on the various temperatures and Fermi level is investigated. In addition, the wave function within the structure is obtained and compared with that from the flat-potential model.

• Steel and Composite Structures
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• v.4 no.1
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• pp.49-75
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• 2004

The paper derives, validates and illustrates the application of GBT-based formulae to estimate distortional critical lengths and bifurcation stress resultants in cold-formed steel rack-section columns, beams and beam-columns with arbitrarily inclined mid-stiffeners and four support conditions. After a brief review of the Generalised Beam Theory (GBT) basics, the main concepts and procedures employed to obtain the formulae are addressed. Then, the GBT-based estimates are compared with exact results and, when possible, also with values yielded by formulae due to Lau and Hancock, Hancock and Teng et al. A few remarks on novel aspects of the rack-section beam-column distortional buckling behaviour, unveiled by the GBT-based approach, are also included.

• Bulletin of Food Technology
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• v.15 no.4
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• pp.29-35
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• 2002

To prevent the incidence of type food allergies, removal of food allergens by excluding all foodstuffs containing the allergen(s) or disruption of allergen(s) using proteases has been employed. Though allergen- specific digestion with a protease worked well in the preparation of low allergenic goods, it is often difficult to destroy allergenicity without adversely affecting the nutritive value, taste and rheological properties of foods. In the present study, we represented that herbs component contained both allergy- enhancing and inhibiting factors, in addition to llergens. We also reported that herbal component such as epigallocatechingallate (EGCG) and epicatechingallate (ECG) is possible to be allergy- inhibiting factors, but the exact mechanism by which they alleviate allergic response is left to be clarifying. Document of allergy enhancing factors and enrichment of allergy inhibiting factors may provide a new approach to diminish allergenicity of various foodstufffs. Clarification of the allergic reaction modifying mechanism of food components and optimization of the intake of allergy modifying factor are necessary for decrement of allergenicity of conventional food and prevention of incidents of allergic response

• Journal of the Korean Institute of Navigation
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• v.23 no.2
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• pp.61-66
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• 1999

It is being more and more difficult to suppress emissions from electronic products using PCB(Printed Circuit Board) to the limit. Therefore, the exact evaluation of the emission from PCB has been more important to reduce the required time and the cost at the design phase of the products, especially on board ship's equipments. This research has evaluated the emission radiated from PCB based on the theoretical approach of SDA(Spectral Domain Analysis), which is available to analyze microwave stripline, coplanar line, patch antenna, etc. According to the theoretical results, it has been clearly shown that the emission radiated from PCB is reduced as the thickness of PCB is thinner, the permittivity of PCB is higher, the length of stripline is shorter, and the frequency is lower.

• The Korean Journal of Ceramics
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• v.5 no.3
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• pp.235-238
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• 1999

In a ceramic green body, some degree of nonuniformity in density always presents. These differences in green density will appear as nonuniform shrinkage after sintering takes place. For the complex ceramic bodies with various curves and angles, therefore, it is quite difficult to foresee the final dimensions precisely after sintering. This simulation study shows that, considering the sintering process as a thermal shrinkage phenomenon, the use of NASTRAN enables to predict the precise shape of a sintered body. Based on this result, 'the reverse engineering technique' has been developed that can unfold the exact dimensions of a green body to have the desired shape after sintering. This approach will provide a simple and useful tool for ceramic engineers to fabricate complicate bodies with tight dimensional tolerances.

• Journal of Ocean Engineering and Technology
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• v.21 no.5
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• pp.1-8
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• 2007

A long wave induced by a Gaussian-shape submarine landslide is simulated by a 2D fully nonlinear numerical wave tank (NWT). The NWT is based on the boundary element method and the mixed Eulerian/Lagrangian approach. Using the NWT, physical characteristics of land-slide tsunami, including wave generation, propagation, particle kinematics, hydrodynamic pressure, run-up and depression, are simulated for the early stage of long wave generation and propagation. Various sliding mass heights are applied to the developed model for a systematic sensitivity analysis. In particular, the fully nonlinear NWT results are compared with linear results (exact body-boundary conditions with linear free-surface conditions) to identify the nonlinear effects in the respective cases.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.26.5-26
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• 2001

This paper proposes a new approach to identifying the unknown parameters of continuous LTI systems. For parameter identification in continuous-time systems, the Linear Integral Filter (LIF) method generally has been used in the beginning. Especially, one of the most efficient LIF methods in the literature is to use a weighting function satisfying specific three constraints. In high order systems, even though the weighting function satisfies the three constraints, it is impossible to identify the exact parameters of the systems because of information loss arising from a great amount of magnitude differences among the weighting function and its high-order derivatives. This paper, using an LMI technique, shows the limitation in designing the weighting function of the existing methods, and ...

• The Journal of Fisheries Business Administration
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• v.32 no.2
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• pp.23-50
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• 2001

The study tries to suggest one kind of method for measuring expost commutative fisheries damages caused by a large scale coastal reclamation. The situation of fisheries damages which the paper is considering is different from those of general cases:the latter is a priori investigation but the former is a posteriori one. Therefore we need a different approach for exact measurement of such kind of fisheries damages. The key contribution of the paper is to try to estimate a decreasing production function using the results of present investigation and several statistical data about our coastal fisheries productivity and environmental deterioration. Using the function, the paper tries to derive the expected catch amount and damage amount.

• Journal of computational fluids engineering
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• v.2 no.2
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• pp.51-58
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• 1997

A reliable computational solver has been developed for the analysis of three-dimensional inviscid compressible flows around a nacelle of a high bypass ratio turbofan engine, The numerical algorithm is based on the modified Godunov scheme to allow the second order accuracy for space variables, while keeping the monotone features. Two step time integration is used not only to remove time step limitation but also to provide the second order accuracy in a time variable. The multi-block approach is employed to calculate the complex flow field, using an algebraic, conformal, and elliptic method. The exact solution of Riemann problem is used to define boundary conditions. The accuracy of the developed solver is validated by comparing its results around the isolated nacelle in the cruise flight regime with the solution obtained using a commercial code "RAMPANT. "