• Title/Summary/Keyword: Central difference method

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Emotion Recognition by Vision System (비젼에 의한 감성인식)

  • 이상윤;오재흥;주영훈;심귀보
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2001.12a
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    • pp.203-207
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    • 2001
  • In this Paper, we propose the neural network based emotion recognition method for intelligently recognizing the human's emotion using CCD color image. To do this, we first acquire the color image from the CCD camera, and then propose the method for recognizing the expression to be represented the structural correlation of man's feature Points(eyebrows, eye, nose, mouse) It is central technology that the Process of extract, separate and recognize correct data in the image. for representation is expressed by structural corelation of human's feature Points In the Proposed method, human's emotion is divided into four emotion (surprise, anger, happiness, sadness). Had separated complexion area using color-difference of color space by method that have separated background and human's face toughly to change such as external illumination in this paper. For this, we propose an algorithm to extract four feature Points from the face image acquired by the color CCD camera and find normalization face picture and some feature vectors from those. And then we apply back-prapagation algorithm to the secondary feature vector. Finally, we show the Practical application possibility of the proposed method.

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Comparison of Waterproofing Preparation Time with the Unfolded of Donut-type Staking Method Fire Hose in Indoor Hydrant System (옥내소화전설비에서 도너츠형 적재방식의 소방호스 전개형태에 따른 방수준비시간 비교)

  • Hong, Suk-Hwan;Kong, Ha-Sung
    • Journal of the Korea Safety Management & Science
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    • v.23 no.3
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    • pp.115-122
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    • 2021
  • In this study, the purpose of this study was to examine the effect of twisting in the preparation of waterproofing in the process of unfolded donut-type staking method fire hoses in indoor hydrant system. The central pull-out method caused more twisting than the rolling method, and there was no significant difference in the number of twists according to the pull-out method in the case of male and female students. It was found that the time it took to untwist and prepare waterproofing was much shorter for male students. The angle valve and hose are connected, and the time to untwist and prepare for waterproofing after withdrawing the fire hose with the hose and nozzle connected was shorter than the unconnected state. In the rolling method, when a hose connected with two 15 m fire hoses was used and the angle valve-hose was connected, but the hose-nozzle was not connected, the least kinking occurred. The time to untwist and prepare for waterproofing was also the shortest. As a result, in the withdrawal method of the donut-type loaded fire hose in the indoor hydrant system, it is a rolling method rather than a central withdrawal method. With the angle valve and hose connected, unfold the fire hose with the hose and nozzle connected, if a large number of people unwind the twisted hose, the time to prepare for waterproofing can be shortened.

Some Modifications of MacCormark's Methods (MacCormack 방법의 개량에 대한 연구)

  • Ha, Young-Soo;Yoo, Seung-Jae
    • Convergence Security Journal
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    • v.5 no.3
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    • pp.93-97
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    • 2005
  • MacCormack's method is an explicit, second order finite difference scheme that is widely used in the solution of hyperbolic partial differential equations. Apparently, however, it has shown entropy violations under small discontinuity. This non-physical shock grows fast and eventually all the meaningful information of the solution disappears. Some modifications of MacCormack's methods follow ideas of central schemes with an advantage of second order accuracy for space and conserve the high order accuracy for time step also. Numerical results are shown to perform well for the one-dimensional Burgers' equation and Euler equations gas dynamic.

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Calculating of the Unrelaxed Surface Energy of Spinel Ferrites (스피넬 페라이트의 비이완 표면에너지 계산)

  • Shin, Hyung-Sup;Sohn, Jeongho
    • Korean Journal of Materials Research
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    • v.25 no.12
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    • pp.713-718
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    • 2015
  • A new method is proposed for the calculation of the unrelaxed surface energy of spinel ferrite. The surface energy calculation consists of (1) setting the central and computational domains in the semi-infinite real lattice, having a specific surface, and having an infinite real lattice; (2) calculation of the lattice energies produced by the associated portion of each ion in the relative domain; and (3) dividing the difference between the semi-infinite lattice energy and the infinite lattice energy on the exposed surface area in the central domain. The surface energy was found to converge with a slight expansion of the domain in the real lattice. This method is superior to any other so far reported due to its simple concept and reduced computing burden. The unrelaxed surface energies of the (100), (110), and (111) of $ZnFe_2O_4$ and $Fe_3O_4$ were evaluated by using in the semi-infinite real lattices containing only one surface. For the normal spinel $ZnFe_2O_4$, the(100), which consisted of tetrahedral coordinated $Zn^{2+}$ was electrostatically the most stable surface. But, for the inverses pinel $Fe_3O_4$, the(111), which consisted of tetrahedral coordinated $Fe^{3+}$ and octahedral coordinated $Fe^{2+}$ was electrostatically the most stable surface.

Baseline-free damage detection method for beam structures based on an actual influence line

  • Wang, Ning-Bo;Ren, Wei-Xin;Huang, Tian-Li
    • Smart Structures and Systems
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    • v.24 no.4
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    • pp.475-490
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    • 2019
  • The detection of structural damage without a priori information on the healthy state is challenging. In order to address the issue, the study presents a baseline-free approach to detect damage in beam structures based on an actual influence line. In particular, a multi-segment function-fitting calculation is developed to extract the actual deflection influence line (DIL) of a damaged beam from bridge responses due to a passing vehicle. An intact basis function based on the measurement position is introduced. The damage index is defined as the difference between the actual DIL and a constructed function related to the intact basis, and the damage location is indicated based on the local peak value of the damage index curve. The damage basis function is formulated by using the detected damage location. Based on the intact and damage basis functions, damage severity is quantified by fitting the actual DIL using the least-square calculation. Both numerical and experimental examples are provided to investigate the feasibility of the proposed method. The results indicate that the present baseline-free approach is effective in detecting the damage of beam structures.

Volume difference in upper central incisor preparation according to the changes of restorative design and marginal location (상악 중절치 삭제 시 수복 디자인과 변연부 위치에 따른 부피 변화)

  • Kim, Chong-Hyun;Park, Young-Bum;Kim, Sung-Tae;Lee, Keun-Woo
    • The Journal of Korean Academy of Prosthodontics
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    • v.49 no.2
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    • pp.152-160
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    • 2011
  • Purpose: The aim of this study was to evaluate the volumetric change of teeth after preparation for various designs and margin locations through Micro CT analysis (Skyscan 1076: SKYSCAN, Konitch, Belgium). Materials and methods: The 36 artificial teeth were used to determine reduction volume of upper central incisor. According to the restorative design these 36 teeth were divided into 4 groups and according to the marginal location each group was divided into 3 subgroups. The volume of unprepared teeth was obtained by using Micro CT and the volume of prepared teeth was obtained in the same method. The CT scanned images before and after preparation were superimposed. Results: The volume difference was significantly increased as follows: traditional laminate veneer < full laminate veneer < all ceramic crown < metal ceramic crown. One-way ANOVA and Tukey multiple comparison analyses were used to analyze the data in this study. In each group the volume difference was significantly increased as follows: 1 mm above CEJ < CEJ < 1 mm below CEJ (P<.05). The % volume difference of all ceramic crown and metal ceramic crown was 31 - 48% and that of laminate veneer was 14 - 30%. The volume difference of the traditional laminate veneer was 1/3 of that of metal ceramic crown. The full laminate (1 mm below CEJ) and all ceramic crown (1 mm above CEJ) showed a similar volume difference. Metal ceramic crown showed 13.7% more volume difference than all ceramic crown. Conclusion: There exists the difference in volumetric change according to designs of restoration and margin locations of preparation.

Perceptual Quality-based Video Coding with Foveated Contrast Sensitivity (Foveated Contrast Sensitivity를 이용한 인지품질 기반 비디오 코딩)

  • Ryu, Jiwoo;Sim, Donggyu
    • Journal of Broadcast Engineering
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    • v.19 no.4
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    • pp.468-477
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    • 2014
  • This paper proposes a novel perceptual quality-based (PQ-based) video coding method with foveated contrast sensitivity (FCS). Conventional methods on PQ-based video coding with FCS achieve minimum loss on perceptual quality of compressed video by exploiting the property of human visual system (HVS), that is, its sensitivity differs by the spatial frequency of visual stimuli. On the other hand, PQ-based video coding with foveated masking (FM) exploits the difference of the sensitivity of the HVS between the central vision and the peripheral vision. In this study, a novel FCS model is proposed which considers both the conventional DCT-based JND model and the FM model. Psychological study is conducted to construct the proposed FCS model, and the proposed model is applied to PQ-based video coding algorithm implemented on HM10.0 reference software. Experimental results show that the proposed method decreases bitrate by the average of 10% without loss on the perceptual quality.

AN IMPLICIT NUMERICAL SCHEME FOR SOLUTION OF INCOMPRESSIBLE NAVIER-STOKES EQUATIONS ON CURVILINEAR GRIDS

  • Fayyaz, Hassan;Shah, Abdullah
    • Bulletin of the Korean Mathematical Society
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    • v.55 no.3
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    • pp.881-898
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    • 2018
  • This article deals with implementation of a high-order finite difference scheme for numerical solution of the incompressible Navier-Stokes equations on curvilinear grids. The numerical scheme is based on pseudo-compressibility approach. A fifth-order upwind compact scheme is used to approximate the inviscid fluxes while the discretization of metric and viscous terms is accomplished using sixth-order central compact scheme. An implicit Euler method is used for discretization of the pseudo-time derivative to obtain the steady-state solution. The resulting block tridiagonal matrix system is solved by approximate factorization based alternating direction implicit scheme (AF-ADI) which consists of an alternate sweep in each direction for every pseudo-time step. The convergence and efficiency of the method are evaluated by solving some 2D benchmark problems. Finally, computed results are compared with numerical results in the literature and a good agreement is observed.

A Study on the Nonlinear Analysis of Dynamic Response of Shell Structure (Shell 구조물의 비선형 동적응답 해석에 관한 연구)

  • Bae, Dong-Myung;Jin, Jong-Dae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.28 no.1
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    • pp.79-92
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    • 1992
  • This is analyzed using the finite element method which is appling excellent isoparametric curve element in the aspect of large usages of dynamic responses in which is regarding geometric and material nonlinear of a large scale shell structure of an airplane, a submarine, a ship, and an ocean structure. The solution of dynamic equations is got by direct integration method using time-stepping procedure and regarding Central Difference Method of the both solutions. But because formal matrix factorization is not necessary in each time step and it does not take less time to compute relatively, this method must be regarded very few time steps on the condition. Axisymmatric shell problems are inspected using 8 node Isoparametric element in this paper. Partial axisymmatric spherical shell is used as a model to analyze axisymmatric nonlinear dynamic behavior regarding. Total Lagrangian formulation in geometric nonlinear behavior and elastio-viscoplastic in material nonlinear behavior.

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A Study on the Motion Analysis for Disk Cam Mechanism Using Circular Arc (원호접근법을 이용한 디스크 캠기구의 운동해석에 관한 연구)

  • Koo, B.K.;Shin, J.H.;Yoon, H.E.;Zhang, Y.H.
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.772-777
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    • 2000
  • Cam mechanisms are used commonly in many automatic machinery. Disk cam mechanisms has 4 different types according to the different types of followers. The motion characteristics of the cam mechanisms depend on the shape of the cam and the type of the follower. This paper performs the motion analysis for a disk cam and follower mechanism using a circular arc method and a coordinate transformation method in order to find a contact point of the cam and follower. The velocity is calculated by using the instant velocity concept. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

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