• Journal of KIISE
• /
• v.45 no.1
• /
• pp.15-21
• /
• 2018

Low-Rank Representation (LRR) based methods are widely used in many practical applications, such as face clustering and object detection, because they can guarantee high prediction accuracy when used to constructing graphs in graph - based semi-supervised learning. However, in order to solve the LRR problem, it is necessary to perform singular value decomposition on the square matrix of the number of data points for each iteration of the algorithm; hence the calculation is inefficient. To solve this problem, we propose an improved and faster LRR method based on the recently published Fast LRR (FaLRR) and suggests ways to introduce and optimize additional constraints on the underlying optimization goals in order to address the fact that the FaLRR is fast but actually poor in classification problems. Our experiments confirm that the proposed method finds a better solution than LRR does. We also propose Fast MLRR (FaMLRR), which shows better results when the goal of minimizing is added.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.15 no.2
• /
• pp.367-377
• /
• 2002

This paper deals with the free vibrations of shallow arches resting on elastic foundations. Foundations we assumed to follow the hypothesis proposed by Pasternak. The governing differential equation is derived for the in-plane free vibration of linearly elastic arches of uniform stiffness and constant mass per unit length. Two arch shapes with hinged-hinged and clamped-clamped end constraints we considered in analysis. The frequency equations (lowest symmetrical and antisymmetrical frequency equations) we obtained by Galerkin's method. The effects of arch rise, Winkler foundation parameter and shear foundation parameter on the lowest two natural frequencies are investigated. The effect of initial arch shapes on frequencies is also studied.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.30 no.2
• /
• pp.174-179
• /
• 1985

Estimate of heritabilities, genotypic and phenotypic correlations and path coefficient analysis were performed for the seven characters of barley cultivars (Hordeum vulgare L.). Heritabilities of broad sense for stem length and spike length were 0.923 and 0.907. Kernels per spike, grain yield and 100 grain weight also showed high heritabilities. High genotypic and phenotypic correlations existed between stem length and 100 grain weight. Grain yield showed highly significant phenotypic correlation with spike length, 100 grain weight and kernels per spike. Genotypic correlations between those characters were moderately high. Number of stem had greatest direct effect but the number of spike had a strong negative direct effect upon grain yield. Kernels per spike via number of spike showed greatest indirect effect and the number of stem via number of spike showed strong negative indirect effect upon grain yield.

• Korean Journal of Food Science and Technology
• /
• v.27 no.3
• /
• pp.387-393
• /
• 1995

Diffusion coefficients of moisture and solid, reaction rate constants of carotene destruction, and the fitness of drying models for moisture transfer were determined to study the characteristics of mass transfer during osmotic dehydration. Moisture loss and solid gain were increased with increase of temperature and concentration; temperature had higher osmotic effect than concentration. Diffusion coefficient showed similar trend with osmotic effect. Diffusion coefficients of solids were larger than those of moisture because the movement of solid was faster than that of moisture at the high temperature. Reaction rate constants were affected to the greater extent by concentration changes than by temperature changes. Arrhenius equation was applied to determine the effect of temperature on diffusion coefficients and reaction rate constants. Moisture diffusion required high activation energy in $20^{\circ}Brix$, while relatively low in $60^{\circ}Brix$. To predict the diffusion coefficients and reaction rate constants, a model was established by using the optimum functions of temperature and concentration. The model had high $R^2$ value when applied to diffusion coefficients, but low when applied to reaction rate constants. Quadratic drying model was most fittable to express moisture transfer during drying. In conclusion, moisture content of carrots could be predictable during the osmotic dehydration process, and thereby mass transfer characteristics could be determined by predicted moisture content and diffusion coefficient.

• Journal of the Korean Society of Industry Convergence
• /
• v.3 no.1
• /
• pp.53-59
• /
• 2000

단섬유 보강 복합재료의 종횡비(aspect ratio)를 변화시키며 기계적 특성(탄성계수, 인장강도)을 평가하였다. 2차원 다중 파이버(multi-fiber) 모델을 이용하여 엇갈린(staggered) 배열과 규칙적(aligned) 배열에 대해 유한요소 해석을 하였다. 단섬유 복합재료의 유효탄성계수 및 인장강도는 섬유와 기지의 탄성계수비, 섬유 배열상태, 그리고 단섬유 종횡비의 함수로 표현되었으며, 해석결과의 탄성계수와 인장강도는 이론 모델의 결과와 사출 성형된 PEEK 복합재료 시험편의 결과와 비교하였다. 시험결과는 낮은 종횡비에서 이론 모델 결과와 일치함을 보였다. 단섬유 보강 복합재료의 배열 및 종횡비 변화에 따른 섬유보강 효과에 따른 계면응력 상태는 기계적 특성 결정에 중요한 영향을 보였다.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.43 no.1 s.307
• /
• pp.91-100
• /
• 2006

A scheme is proposed for implementing the block LMS algorithm in a block floating point framework that permits processing of data over a wide dynamic range at a processor complexity and coat as low as that of a fixed point processor. The proposed scheme adopts appropriate formats for representing the filter coefficients and the data. Using these and a new upper bound on the step size, update relations for the filter weight mantissas and exponent are developed, taking care so that neither overflow occurs, nor are quantifies which are already very small multiplied directly. It is further shown how the mantissas of the filter coefficients and also the filter output can be evaluated faster by suitably modifying the approach of the fast block LMS algorithm

• Journal of Broadcast Engineering
• /
• v.9 no.1
• /
• pp.17-31
• /
• 2004

This paper proposes an algorithm for the robust transmission of video in error Prone environment using multiple description codingby optimal split of DCT coefficients and rate-distortionoptimization framework. In MDC, a source signal is split Into several coded streams, which is called descriptions, and each description is transmitted to the decoder through different channel. Between descriptions, structured correlations are introduced at the encoder, and the decoder exploits this correlation to reconstruct the original signal even if some descriptions are missing. It has been shown that the MDC is more resilient than the singe description coding(SDC) against severe packet loss ratecondition. But the excessive redundancy in MDC, i.e., the correlation between the descriptions, degrades the RD performance under low PLR condition. To overcome this Problem of MDC, we propose a hybrid MDC method that controls the SDC/MDC switching according to channel condition. For example, the SDC is used for coding efficiency at low PLR condition and the MDC is used for the error resilience at high PLR condition. To control the SDC/MDC switching in the optimal way, RD optimization framework are used. Lagrange optimization technique minimizes the RD-based cost function, D+M, where R is the actually coded bit rate and D is the estimated distortion. The recursive optimal pet-pixel estimatetechnique is adopted to estimate accurate the decoder distortion. Experimental results show that the proposed optimal split of DCT coefficients and SD/MD switching algorithm is more effective than the conventional MU algorithms in low PLR conditions as well as In high PLR condition.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.09a
• /
• pp.180-183
• /
• 2001

오염물 이동에 영향을 미치는 지연계수는 용질과 시료의 흡착특성을 나타낸다. 흡착특성을 표현하는 데에는 Freundlich등온식, Langmuir등온식 또는 선형등온식등을 사용할 수 있는 데, 본 연구에서는 상관계수를 이용하여 각등온식의 적용성을 평가하고 용질이동 수치해 석을 하여 농도가 10ppm 이하로 낮을 경우의 용질이동정도를 상호 비교하였다. 아연, 크롬, 납에 대한 등온식의 상관계수에 따른 적용성 평가결과 Freundlich 등온식이 보편적으로 적용 가능한 것으로 나타났고, 수치해석 결과 농도가 10ppm 이하일 경우는 용질이동성이 동일하게 나타났다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.7
• /
• pp.585-590
• /
• 2017

Vehicle behavior is determined by forces and a torques generated at the ground contact surface of the tire. Various tire models are used to calculate the forces and torques acting on the tire. The brush model calculates the forces and torques with fewer coefficients than other tire models. However, owing to fewer degrees of freedom in calculating the forces, this model has limitations in precisely expressing measured data. In this study, this problem was addressed by adding the least parameters to the friction coefficient and tire properties of the brush model, and the proposed model was validated.

• Korean Journal of Optics and Photonics
• /
• v.35 no.1
• /
• pp.1-8
• /
• 2024

Explicit expressions for the transmission pseudo-ellipsometric constants and transmittance of a semi-transparent glass substrate coated with thin films are presented to determine the optical constants of a very weakly absorbing thin film coated on a glass substrate. The intensity of the multiply reflected light inside the semi-transparent substrate is superposed incoherently and the light absorption by the substrate is properly treated, so that modeling analysis of thin films coated on a semi-transparent substrate can be performed with increased accuracy. The extinction coefficient derived from transmittance analysis is compared to that from ellipsometric analysis in the weakly absorbing region, and the difference between the two extinction coefficients is discussed in relation to the sensitivities of the transmittance and ellipsometric constants. This transmittance analysis, together with ellipsometric analysis, is applied to a glass substrate coated with a SiN thin film, and it is shown that the thickness and complex refractive index of the SiN thin film can be determined accurately, even though the extinction coefficient is very small.