• The Bulletin of The Korean Astronomical Society
• /
• v.22
• /
• pp.30.1-30.1
• /
• 1997

• Journal of Sensor Science and Technology
• /
• v.25 no.6
• /
• pp.431-434
• /
• 2016

Currently, the radial basis function network (RBFN) and various other neural networks are employed to classify gases using chemical sensors arrays, and their performance is steadily improving. In particular, the identification performance of the RBFN algorithm is being improved by optimizing parameters such as the center, width, and weight, and improved algorithms such as the radial basis function network-stochastic gradient (RBFN-SG) and radial basis function network-normalized stochastic gradient (RBFN-NSG) have been announced. In this study, we optimized the number of centers, which is one of the parameters of the RBFN-NSG algorithm, and observed the change in the identification performance. For the experiment, repeated measurement data of 8 samples were used, and the elbow method was applied to determine the optimal number of centers for each sample of input data. The experiment was carried out in two cases(the only one center per sample and the optimal number of centers obtained by elbow method), and the experimental results were compared using the mean square error (MSE). From the results of the experiments, we observed that the case having an optimal number of centers, obtained using the elbow method, showed a better identification performance than that without any optimization.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.34C no.4
• /
• pp.36-44
• /
• 1997

An efficient context-free multiple-object segmentation using attention operator based on modified generalized symmetry transform is proposed and implemented by modifying a radial basis function network. By using the difference of intensity gradient, instead of te intensity gradient itself, in generalized symmetry tranform so as to make the attention operator to preserve the edges of the objects shape, an efficient context-free multiple-object segementation is proposed in which no a priori shape informtion on the objects is requried. The attention operator is implemented by using a modified radial basis function network which can reflect symmetry, and by using te edge pyramid of the input image, both of the local and the global symmetry of the objects are reflected simultaneously to make the multiple-object with different sizes be segmented with a singel fixed-size $n\timesm$ can be done with O(n) complexity. The simulaton results show that the proposed algorithm can efficiently be used in context-free multiple-object segmentation even for the low contrast IR images as well as for the images from the camera.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.10 no.2
• /
• pp.91-95
• /
• 2000

The effects of argon gas flow on the axial temperature gradient near the interface, the oxygen concentration, and the radial oxygen uniformity was investigated for 8-inch CZ silicon growth. As argon flow rate was increased, the temperature gradient was increased in the crystal near the crystavmelt interface and the oxygen content in the crystal was decreased. But the radial oxygen uniformity was deteriorated. It was found that argon flow is one of the important growing parameters to affect the quality of crystals such as oxygen content and uniformity.

• Archives of Pharmacal Research
• /
• v.3 no.1
• /
• pp.13-16
• /
• 1980

The model of an isolated organ system has been constructed to simulated the behavior of drug in the circulatory system of an acting organ or site. The model is developed on the following assumptions : The drug in the microcirculatory system cannot permeate the capilary walls. The capilary bed is modeled as a simple ideal plug flow system with and without radial concentration gradient. The mathematical model is developed from basic considerations of drug distribution with hemodynamical and pharmacokinetical meanings. It is considered that a nonmetabolic drug substance is injected into the arterial inflow site of an isolated organ at a constant rate. The concentration of the drug in the outflow site is mathematically expressed as a function of time.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.04a
• /
• pp.530-533
• /
• 2011

방사형 그라디언트 페인트(radial gradient paint)는 벡터 그래픽스(vector graphics)에서 적은 정보로 다양한 효과를 적용시킬 수 있는 방법이다. 기본적으로 이 방법은 곱하기, 나누기, 제곱근 등의 복잡한 연산이 필요하기 때문에 모바일 같은 저성능 환경에 적합하지 않았다. 하지만 최근 모바일 기기들은 SIMD 연산 지원 및 고성능의 GPU 탑재 등으로 성능이 향상됨에 따라 이러한 문제를 해결할 수 있게 되었다. 본 논문은 ARM의 SIMD연산인 NEON을 이용하여 최대 2.6배의 성능을 가속시켰으며 GPU의 쉐이더를 이용하여 4.9배의 성능을 가속하였다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.3
• /
• pp.151-157
• /
• 2021

This paper is devoted to a convergence study of the nonlocal integral operator in peridynamics. The implicit formulation can be an efficient approach to obtain the static/quasi-static solution of crack propagation problems. Implicit methods require constly large-matrix operations. Therefore, convergence is important for improving computational efficiency. When the radial influence function is utilized in the nonlocal integral equation, the fractional Laplacian integral equation is obtained. It has been mathematically proved that the condition number of the system matrix is affected by the order of the radial influence function and nonlocal horizon size. We formulate the static crack problem with peridynamics and utilize Newton-Raphson methods with a preconditioned conjugate gradient scheme to solve this nonlinear stationary system. The convergence behavior and the computational time for solving the implicit algebraic system have been studied with respect to the order of the radial influence function and nonlocal horizon size.

• The Bulletin of The Korean Astronomical Society
• /
• v.32 no.1
• /
• pp.101.1-101.1
• /
• 2007

• Bulletin of the Korean Space Science Society
• /
• 2009.10a
• /
• pp.34.4-35
• /
• 2009

We have studied the radial g-r color gradients of early-type galaxies in the Sloan Digital Sky Survey (SDSS) DR6 in the redshift range 0.00 < z < 0.06. The color profiles of ~30 per cent of the galaxies in this sample show positive color gradients (centers being bluer). These positive gradient galaxies often show strong $H\beta$ absorption line strengths or emission line ratios that are consistent with star-forming populations. Combining the optical data with Galaxy Evolution Explorer (GALEX) UV photometry, we find that all positive gradient galaxies show blue UV-optical colors. They also exhibit a tendency of having a lower stellar velocity dispersion. Positive gradient galaxies tend to live in lower density regions than negative gradient galaxies and are likely to have a late-type companion galaxy. On the other hand, massive early-type galaxies show negative color gradients. A simplistic population analysis shows that these positive color gradients are visible only for half a billion years after a star burst. Although the effective radius decreases and mean surface brightness increases due to this centrally concentrated star formation, the positions of the positive gradient galaxies on the fundamental plane cannot be reproduced by any amount of recent star formation. Instead it required a lower velocity dispersion.

• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.468-470
• /
• 1986

An optimal control in heat-up operation was formulated for minimizing the quadratic performance criterion which is a function of temperature, temperature gradient in the wall and fuel flow rate. For optimal control law computations mathematical model was simplified with assumptions and then linearized by use of orthogonal collocation in radial direction. Effects of weighting function assigned to temperature and temperature gradient and final time were compared with industrial data.