• Journal of the Korean Solar Energy Society
• /
• v.23 no.3
• /
• pp.73-80
• /
• 2003

The purpose of this study was to analyze daylighting performance in a semi-infinite size office space for lighting energy conservation. DOE2.1E was used for simulations for the model space of $12\times12\times2.6m$. Nomographs were developed which could simulate work plane illuminance, glare index, energy consumption rate and energy reduction rate for daylighting design. Major results of simulations are as follows ; 1) When blinds facing south were installed, 43% of workplane illuminance diminished, but the flare index didn't exceed the recommended max-glare value. 2) In a semi-infinite office space facing south. energy consumption rate in the case space of 500 lux workplane illuminance is larger then case space of 300 lux workplane illuminance. Therefore, energy reduction rate is increased when the semi-infinite office faces south and naintains 300 lux workplane illuminance level.

• Journal of KSNVE
• /
• v.8 no.5
• /
• pp.974-980
• /
• 1998

The analysis of dynamic responses are carried out on several orthotropic systems due to transient line source. These include infinite and semi-infinite spaces. The media possess orthotropic or higher symmetry. The lode is in the form of a normal stress acting with parallel to symmetry axis on the plane of symmetry within the materials. The results are first derived for responses of infinite media due to a harmonic line source. Subsequently the results for semi-infinite are derived by using superposition of the solution in the infinite medium together with a scattered solution from the boundaries. The sum of both solutions has to satisfy stress free boundary conditions thereby leading to the complete solutions. Explicit splutions for the displacements due to transient line loads are then obtaind by using Cargniard-DeHoop contour.

• Journal of applied mathematics & informatics
• /
• v.30 no.5_6
• /
• pp.759-772
• /
• 2012

In this paper, semi-infinite constrained programming, a class of constrained nonsmooth optimization problems, are transformed into unconstrained nonsmooth convex programs under the help of exact penalty function. The unconstrained objective function which owns the primal-dual gradient structure has connection with $\mathcal{VU}$-space decomposition. Then a $\mathcal{VU}$-space decomposition method can be applied for solving this unconstrained programs. Finally, the superlinear convergence algorithm is proved under certain assumption.

• International Journal of Aeronautical and Space Sciences
• /
• v.2 no.2
• /
• pp.46-55
• /
• 2001

A Green's function approach based on the laminate theory is adopted to obtain the unsteady temperature distributions in a semi-infinite hollow circular cylinder made of functionally graded materials (FGMs). The transient heat conduction equation based on the laminate theory is formulated into an eigenvalue problem for each layer by using the eigenfunction expansion theory and the separation of variables. The eigenvalues and the corresponding eigenfunctions obtained by solving an eigenvalue problem for each layer constitute the Green's function solution for analyzing the unsteady temperature distributions. Numerical calculations are carried out for the semi-infinite hollow circular FGM cylinder subjected to partially heated loads, and the numerical results are shown in figures.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2000.04a
• /
• pp.451-457
• /
• 2000

In many dynamic problems such as foundation vibrations ultrasonic nondestructive evaluation and blasting analysts are confronted with the problem of wave propagation in an infinite or semi-infinite media. In order to simulate this situation by a finite analytical model provisions must be made to absorb the stress waves arriving at the boundary. Absorbing boundaries are mathematical artifacts used to prevent wave reflections at the boundaries of discrete models for infinite media under dynamic loads. An analytical study is carried out to examine the effectiveness of Lysmer-Kuhlemeyer model one of the most widely used absorbing boundaries. Validity of the absorbing boundary conditions suggested by Lymer-Kuhlemeyer is examined by adopting the solution of Ewing et al. to the problem of plane waves from a harmonic normal force on the surface of an elastic half-space. The Ewing's problem is than numerically simulated using the finite element method on a semi-circular mesh with and without absorbing boundaries which are represented by viscous dashpots. The absorption ratios are calculated by comparing the displacements at the absorbing boundaries to those at the free field without absorbing boudaries.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.4
• /
• pp.606-611
• /
• 2012

The similarity, analogy and equivalence between the phenomenon due to electric and magnetic dipoles have been discussed in the open literature for different situations. Here we are presenting the numerical proof of the trajectory of leakage electric field due to a semi-infinite electric dipole layer in the external periphery and the electric field in the space between oppositely charged surfaces. The result is also valid for the fringing electric field of a parallel plate capacitor. The result is also proved to be a dual of Amp$\grave{e}$re's law in the electrostatics due to a semi-infinite electric dipole layer.

• Bulletin of the Korean Mathematical Society
• /
• v.48 no.4
• /
• pp.813-838
• /
• 2011

In this paper, we prove sufficient conditions for controllability of second order semi-linear neutral impulsive differential inclusions on unbounded domain with infinite delay in Banach spaces using the theory of strongly continuous Cosine families. We shall rely on a fixed point theorem due to Ma for multi-valued maps. The controllability results in infinite dimensional space has been proved without compactness on the family of Cosine operators.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.9
• /
• pp.816-822
• /
• 2011

In this study, a program has been coded to evaluate propeller thrust rapidly following the effects of propeller shapes and the environmental facts. At this time, Semi-infinite Helical Vortices model is used to predict the induction factor which is introduced by Kawada. This program is based on Wrench's Propeller lifting line theory, and it can predict aerodynamic coefficients such as thrust, power, and efficiency. First of all, this program is compared with test results of NACA reports to verify of the reliability. Secondly, subsonic wind tunnel test has been performed following variations of propeller's rpm and inflow velocities.

• The Bulletin of The Korean Astronomical Society
• /
• v.32 no.1
• /
• pp.36.1-36.1
• /
• 2007

• Journal of KSNVE
• /
• v.7 no.1
• /
• pp.43-53
• /
• 1997

This paper investigated the practical use for measuring the structural intensity (power flow per width of cross section) in a uniform semi-infinite beam in flexural vibration. The structural intensity is obtained as a vector at a measurement point, One-dimensional structural intensity can be obtained from 4-point cross spectral measurement, or 2-point measurement on the assumption of far field. The measurement errors due to finite difference approximation and phase mismatch of accelerometers are examined. For precise measurements, it would be better to make the value of k$\delta$(wave number x space between accelerometers) between 0.5 and 1.0. Formulation of the relation between bending waves in structures and structural intensity makes it possible to separate the wave components by which one can get a state of the vibration field. Experimental results are obtained from 2- and 4-point measurement performed at 200mm (near field) and 400mm (far field) apart from excitation point in random excitation. the results are compared with the theoretical values and measured values of input power spectrum in order to verify the accuracy of structural intensity method, 2-point method is suggested as the practical structural intensity method.