• Title, Summary, Keyword: Constraint

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A study on fuzzy constraint line clustering for optical flow estimation (Optical Flow 추정을 위한 Fuzzy constraint Line Clustering에 관한 연구)

  • 김현주;강해석;이상홍;김문현
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.9
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    • pp.150-158
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    • 1994
  • In this paepr, Fuzzy Constraint Line Clustering (FCLC) method for optical flow estimation is proposed. FCLC represents the spatical and temporal gradients as fuzzy sets. Based on these sets, several constraint lines with different membership values are generated for the poxed whose velocity is to be estimated. We describe the process for obtaining the membership values of the spatial and temporal gradients and that of the corresponding constraint line. We also show the process for deciding the tightest cluster of point formalated by intersection between constraint lines. For the synthetic and real images, the results of FCLC are compared with of CLC.

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A Geometric Constraint Solver for Parametric Modeling

  • Jae Yeol Lee;Kwangsoo Kim
    • Korean Journal of Computational Design and Engineering
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    • v.3 no.4
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    • pp.211-222
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    • 1998
  • Parametric design is an important modeling paradigm in CAD/CAM applications, enabling efficient design modifications and variations. One of the major issues in parametric design is to develop a geometric constraint solver that can handle a large set of geometric configurations efficiently and robustly. In this appear, we propose a new approach to geometric constraint solving that employs a graph-based method to solve the ruler-and-compass constructible configurations and a numerical method to solve the ruler-and-compass non-constructible configurations, in a way that combines the advantages of both methods. The geometric constraint solving process consists of two phases: 1) planning phase and 2) execution phase. In the planning phase, a sequence of construction steps is generated by clustering the constrained geometric entities and reducing the constraint graph in sequence. in the execution phase, each construction step is evaluated to determine the geometric entities, using both approaches. By combining the advantages of the graph-based constructive approach with the universality of the numerical approach, the proposed approach can maximize the efficiency, robustness, and extensibility of geometric constraint solver.

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Hierarchical Constraint Network Representation of Concurrent Engineering Models (동시성공학 모형의 계층적 제약식 네트워크 표현 방법론)

  • Kim, Yeong-Ho
    • Journal of Korean Institute of Industrial Engineers
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    • v.22 no.3
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    • pp.427-440
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    • 1996
  • Constraint networks are a major approach to knowledge representation in Concurrent Engineering (CE) systems. The networks model various factors in CE as constraints linked by shared variables. Many systems have been developed to assist constraint network processing. While these systems can be useful, their underlying assumption that a solution must simultaneously satisfy all the constraints is often unrealistic and hard to achieve. Proposed in this paper is a hierarchical representation of constraint networks using priorities, namely Prioritized Constraint Network (PCN). A mechanism to propagate priorities is developed, and a new satisfiability definition taking into account the priorities is described. Strength of constraint supporters can be derived from the propagated priorities. Several properties useful for investigating PCN's and finding effective solving strategies ore developed.

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Safety Evaluation for PSCI-Beam by Tilt-Constructed with Constraint and Deviation of Bearings (받침의 구속과 편기를 갖는 경사지게 설치된 PSCI빔의 안전성 평가)

  • Park, Chang-Ho;Shin, Jae-In;Lee, Byeong-Ju;Seo, Sang-Gul
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.346-349
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    • 2006
  • Superstructure of reinforced concrete bridges are shortened or elongated due to creep, drying shrinkage, temperature and so on. Most of bridge superstructures are free to shortening and elongation without constraint and stresses will not be induced by creep, drying shrinkage and temperature. But if bridge superstructure are constraint due to wrong setting and functional defects of bridge bearing, very large constraint forces can be induced. In this study, PSCI-Beam by tilt-constructed with constraint and deviation of bearings are presented and the effects of time-dependent constraint stress and temperature loads are investigated.

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The Influence of the constraint condition on the Roller-rig (주행시험대 구속조건에 따른 영향 분석)

  • Kim, Nam-Po;Park, Joon-Hyuk
    • Proceedings of the KSR Conference
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    • pp.1074-1079
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    • 2011
  • This paper describes the influence on the nonlinear critical speed results of a specific railway vehicle depending on various constraint conditions. In the roller-rig tests, proper constraints are inevitable to safely hold the test vehicles. Particularly, the test results using KRRI roller-rig are more sensitive to constraint conditions because it is a kind of semi-full car type. In this study, nonlinear critical speed of specific vehicle with regards to several constraint cases were predicted by computational analysis and these results were compared to find the suitable constraint conditions. And also the deviation of semi-full car model from actual full car model was investigated. According to the bifurcation analysis, the nonlinear critical speed are dependent with the constraint condition and car-body yaw motion should be free to achieve more accurate results. And the difference between semi-full and full car model was so small that KRRI's semi-full car model are valid as long as the stability is concerned.

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BPN Based Approximate Optimization for Constraint Feasibility (구속조건의 가용성을 보장하는 신경망기반 근사최적설계)

  • Lee, Jong-Soo;Jeong, Hee-Seok;Kwak, No-Sung
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.141-144
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    • 2007
  • Given a number of training data, a traditional BPN is normally trained by minimizing the absolute difference between target outputs and approximate outputs. When BPN is used as a meta-model for inequality constraint function, approximate optimal solutions are sometimes actually infeasible in a case where they are active at the constraint boundary. The paper describes the development of the efficient BPN based meta-model that enhances the constraint feasibility of approximate optimal solution. The modified BPN based meta-model is obtained by including the decision condition between lower/upper bounds of a constraint and an approximate value. The proposed approach is verified through a simple mathematical function and a ten-bar planar truss problem.

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Experimental Constraint Effect $A_{2}$, Values depending on Displacement according to measuring Positions near Crack Front. (균열선단 근방 변위측정 위치에 따른 구속효과 $A_{2}$)

  • Han, Min-Su;Jang, Seok-Ki;Lee, Don-Chool;Kim, Seong-Jong
    • Proceedings of the KSME Conference
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    • pp.25-30
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    • 2004
  • The magnitude of constraint effect $A_{2}$ values were experimentally estimated using displacement according to measuring positions on the non-linear elastic plastic fracture toughness estimate. For 25.4 mm thickness SS400 steel CT specimen, constraint effect $A_{2}$ values we re dependent on specimen configuration and on measured displacement near crack front. Commonly, Estimating constraint effect $A_{2}$ measuring position for displacement should be existed inside plastic region. Therefore, the ${\delta}_{5}$ method was not reliable for evaluation of constraint effect $A_{2}$ values because measuring position for displacement is in elastic region at crack growth initiation in this paper.

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The Leisure Constraint and Leisure Life Satisfaction of the Institutionalized Elderly in Seoul - Focusing on the Free Institutionalized Elderly - (서울시 시설거주 노인의 여가프로그램제약정도와 여가생활만족도 - 무료양로시설을 중심으로 -)

  • Park Mee Sok
    • Journal of the Korean Home Economics Association
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    • v.43 no.4
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    • pp.203-223
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    • 2005
  • This study investigated the leisure constraints and leisure life satisfaction of the institutional elderly. The respondents were 302 elderly people residing in 5 free institutionalized elderly homes in Seoul. The data were analyzed by frequency analysis, factor analysis, One-way ANOVA, Duncan's post hoc test and regression analysis using SPSS WIN 12.0 program. Exploratory factor analysis revealed that the 10 items in the proposed scale could be grouped into four factors of constraint on leisure:'physical constraint','psychological constraint','interpersonal constraint', and 'structural constraint 'There were differences in leisure constraints according to sex, age, education degree, interaction with facility colleagues, and interaction with facility staff. There were differences in leisure life satisfaction according to sex, age, having religion or not, interaction with facility colleagues, interaction with facility staff and leisure constraints. Regression analysis results indicated that the main effective factors of leisure life satisfaction were leisure constraints.

A Study on the Dynamic Analysis of Railway Vehicle by Using Track Coordinate System (트랙좌표계를 이용한 철도차량의 동역학 해석에 관한 연구)

  • Kang, Juseok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.2
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    • pp.122-130
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    • 2013
  • Rail geometries such as cant, grade and curvature can be easily represented by means of a track coordinate system. In this analysis, in order to derive a dynamic and constraint equation of a wheelset, the track coordinate system is used as an intermediate stage. Dynamic and constraint equations of railway vehicle bodies except the wheelset are written in the Cartesian coordinate system as a conventional method. Therefore, whole dynamic equations of a railway vehicle are derived by combining wheelset dynamic equations and dynamic equations of railway vehicle bodies. Constraint equations and constraint Jacobians are newly derived for the track coordinate system. A process for numerical analysis is suggested for the derived dynamic and constraint equations of a railway vehicle. The proposed dynamic analysis of a railway vehicle is validated by comparison against results obtained from VI-RAIL analysis.

Evaluation of Fracture Toughness considering Constraint Effect of Reactor Pressure Vessel Nozzle (원자로압력용기 노즐부 구속효과를 고려한 파괴인성 평가)

  • Kweon, Hyeong Do;Lee, Yun Joo;Kim, Dong Hak;Lee, Do Hwan
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.15 no.1
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    • pp.71-76
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    • 2019
  • Actual stress distributions in the nozzle of a pressure vessel may not be in plane strain condition, implying that the crack-tip constraint condition may be relaxed in the nozzle. In this paper, a methodology for evaluating the fracture toughness of the ASME Code is presented considering the relaxation of the constraint effect in the nozzle of the reactor pressure vessel. The crack-tip constraint effect is quantified by the T-stress. The equation, which represent the relation between the fracture toughness in the lower constraint condition and the plane strain fracture toughness, is derived using the T-stress. This equation is similar to the method for evaluating the fracture toughness of the Master Curve for low constraint conditions. As a result of evaluating the fracture toughness considering the constraint effect in the reactor inlet, outlet and direct injection nozzles using the proposed equation, it was confirmed that the fracture toughness in the nozzles is higher than the plane strain fracture toughness. Applying the proposed evaluation methodology, it is possible to reflect the relaxation of the constraint effect in the nozzles of the reactor pressure vessel, therefore, the safe operation area on the pressure-temperature limit curve can be prevented from being excessively limited.