• Title/Summary/Keyword: constraint function

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Dynamic rt-VBR Traffic Characterization using Sub-Sum Constraint Function (Sub-Sum Constraint Function을 이용한 동적 실시간 VBR 트래픽 특성화)

  • 김중연;정재일
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.217-220
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    • 2000
  • This paper studies a real-time VBR traffic characterization. There are two big approaches to determine traffic. One is a statistic approach and the other is a deterministic approach. This paper proposes a new constraint function, what we called “Sub-Sum Constraint Function”(SSCF). This function is mainly based on a deterministic approach and uses a statistic approach. It predicts and calculates the next rate with a present information about the stream. SSCF captures the intuitive bounded by a rate lower than its peak rate and closer to its long-term average rate. This model makes a order of the constraint function much less than any other works (O(n)). It can also be mapped on a token bucket algorithm which consists of r (token rate) and b (token depth). We use a concept, EB(effective bandwidth) for a utility of our function and comparing with other techniques such as CBR, average VBR. We simulated 21 multimedia sources for verifying the utility of our function.

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A Study on Constraint Accumulation in Mathematical Programming Problems Using Envelope Functions (덮개 함수를 이용한 제한 조건 누적 최적화 기법에 관한 연구)

  • Lee, Byeong-Chae;Lee, Jeong-Jun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.4
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    • pp.720-730
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    • 2002
  • Automated design of large structures requires efficient and accurate optimization algorithms because of a large number of design variables and design constraints. The objective of this study is to examine the characteristics of the Kreisselmeier -Steinhauser envelope function and to investigate va tidily of accumulating constraint functions into a small number of constraint functions or even into a single constraint function. The commercial package DOT is adopted as a local optimizer. The optimum results using the envelope function are compared with those of the conventional method for a number of numerical examples and the differences between them are shown to be negligible.

Constraint Operator for the Kinematic Calibration of a Parallel Mechanism

  • Lee, Min-Ki;Kim, Tae-Sung;Park, Kun-Woo;Kwon, Sung-Ha
    • Journal of Mechanical Science and Technology
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    • v.17 no.1
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    • pp.23-31
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    • 2003
  • This paper introduces a constraint operator for the kinematic calibration of a parallel mechanism. By adopting the concept of a constraint operator, the movement between two poses is constrained. When the constrained movements are satisfied, the active joint displacements are taken and inputted into the kinematic model to compute the theoretical movements. A cost function is derived by the errors between the theoretical movement and the actual movement. The parameters that minimize the cost function are estimated and substituted into the kinematic model for a kinematic calibration. A single constraint plane is employed as a mechanical fixture to constrain the movement, and three digital indicators are used as the sensing devices to determine whether the constrained movement is satisfied. This calibration system represents an effective, low cost and feasible technique for a parallel mechanism. A calibration algorithm is developed with a constraint operator and implemented on a parallel manipulator constructed for a machining center tool.

An Algorithm for the Concave Minimization Problem under 0-1 Knapsack Constraint (0-1 배낭 제약식을 갖는 오목 함수 최소화 문제의 해법)

  • Oh, S.H.;Chung, S.J.
    • Journal of Korean Institute of Industrial Engineers
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    • v.19 no.2
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    • pp.3-13
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    • 1993
  • In this study, we develop a B & B type algorithm for the concave minimization problem with 0-1 knapsack constraint. Our algorithm reformulates the original problem into the singly linearly constrained concave minimization problem by relaxing 0-1 integer constraint in order to get a lower bound. But this relaxed problem is the concave minimization problem known as NP-hard. Thus the linear function that underestimates the concave objective function over the given domain set is introduced. The introduction of this function bears the following important meanings. Firstly, we can efficiently calculate the lower bound of the optimal object value using the conventional convex optimization methods. Secondly, the above linear function like the concave objective function generates the vertices of the relaxed solution set of the subproblem, which is used to update the upper bound. The fact that the linear underestimating function is uniquely determined over a given simplex enables us to fix underestimating function by considering the simplex containing the relaxed solution set. The initial containing simplex that is the intersection of the linear constraint and the nonnegative orthant is sequentially partitioned into the subsimplices which are related to subproblems.

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The Effects of Constraint-Induced Movement Therapy on Improvement of Hand Function in Hemiplegic Side (Constraint-Induced Movement Therapy가 편마비측 손기능 증진에 미치는 영향)

  • Ryu, In-Tae;Hwang, Byong-Yong;Kim, Ji-Hye;Chung, Sang-Mi
    • The Journal of Korean Physical Therapy
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    • v.21 no.2
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    • pp.9-14
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    • 2009
  • Purpose: This study examined the effect of constraint-induced movement therapy (CIMT) on improving the hand function in hemiplegic side. Methods: Ten subjects without a control group were given CIMT to the hemiplegic side for 3 weeks. The effects of their hand function and sensibility were examined using a MAL and two point discrimination test. Repeated ANOVA was carried out for an analysis of the effects of the application of CIMT before and after treatment. Results: The participants showed significant improvement in their functional aspect with CIMT while there were no significant changes in the time domain variables. There was significant improvement in the quantitative and qualitative aspect of MAL, as well as significant improvement in the two-point discrimination function in all fingers. Conclusion: CIMT can enhance the motor function and sensory function of the hand in hemiplegic patients.

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Effects of Upper Extremity Exercise Training Using Biefeedback and Constraint-induced Movement on the Upper Extremity Function of Hemiplegic Patients (바이오피드백과 건측 억제유도 운동을 이용한 상지운동훈련이 편마비 환자의 상지기능에 미치는 효과)

  • 김금순;강지연
    • Journal of Korean Academy of Nursing
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    • v.33 no.5
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    • pp.591-600
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    • 2003
  • Purpose: The purpose of this study was to investigate the effects of exercise training using biofeedback and constraint-induced movement on the upper extremity function of hemiplegic patients. Method: A non-equivalent pretest-posttest design was used. Study subjects were a conveniently selected group of 40 hemiplegic patients(20 experimental subjects, 20 control subjects) who have been enrolled in two community health centers. After biofeedback training the subjects of experimental group were given constraint-induced movement, involving restraint of unaffected U/E in a sling for about 6 hours in a day over a period of two weeks, while at the same time intensively training the affected U/E. Outcomes were evaluated on the basis of the VIE motor ability(hand function, grip power, pinch power, U/E ROMs), and motor activity(amount, quality). Result: 1. After 2 weeks of treatment, the motor abilities of affected U/E(hand function, grip power, pinch power, ROMs of wrist flexion, elbow flexion and shoulder flexion/extension) were significantly higher in subjects who participated in exercise training than in subjects in the control group with no decrement at 4-week follow-up. However, there was no significant difference in wrist extension between experimental or control group. 2. After 2 weeks of treatment, the amount of use and the quality of motor activity of affected U/E were significantly higher in subjects who participated in exercise training than in subjects in the control group with no decrement at 4-week follow-up. Conclusion: The above results state that exercise training using biofeedback and constraint-induced movement could be an effective intervention for improving U/E function of chronic hemiplegic patients. Long-term studies are needed to determine the lasting effects of constraint-induced movement.

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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    • 2007.04a
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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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Effects of Constraint-Induced Movement Using Self-Efficacy Enhancing Strategies on the Upper Extremity Function of Chronic Hemiplegic Patients (자기효능증진전략을 이용한 건측억제유도운동이 편마비 환자의 상지기능에 미치는 효과)

  • Kang, Ji-Yeon
    • Journal of Korean Academy of Nursing
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    • v.36 no.2
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    • pp.403-414
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    • 2006
  • Purpose: The purpose of this study was to investigate the effects of constraint-induced (CI) movement using self-efficacy on U/E function of chronic hemiplegic patients. CI movement discourages the use of the unaffected U/E, combined with intensive training of the affected U/E. Method: A non-equivalent pretest-posttest design was used. Study subjects were 40 hemiplegic patients conveniently selected from 2 different community health centers. The experimental subjects participated in the CI movement program for 6 hours daily over a period of two weeks. The exercises for affected U/E consisted of warming up, main exercise and ADL practice. To encourage the participants' behaviors self-efficacy enhancing strategies were used, which included performance accomplishment, vicarious experience, verbal persuasion and emotional arousal. Result: After 2 weeks of treatment, the grip power, pinch power, wrist flexion/extension, elbow flexion, and shoulder flexion/extension were significantly higher in the experimental subjects than in the control subjects. However, there was no significant difference in hand functions of the two groups. Conclusion: The above results show that the constraint-induced movement using self-efficacy could be an effective nursing intervention for improving U/E function of chronic hemiplegic patients. Long term studies are needed to determine the lasting effects of constraint-induced movement.

Improvement of the Stratospheric Wind Analysis with the Climatological Constraint in the Global Three-Dimensional Variational Assimilation at Korea Meteorological Administration (3차원 변분법의 제한조건 적용을 통한 기상청 전지구 모델의 성층권 바람장 개선)

  • Joo, Sangwon;Lee, Woo-Jin
    • Atmosphere
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    • v.17 no.1
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    • pp.1-15
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    • 2007
  • A constraint based on climatology is introduced to the cost function of the three-dimensional variational assimilation (3dVar) to correct the error of the zonal mean wind structure in the global data assimilation system at Korea Meteorological Administration (KMA). The revised cost function compels the analysis fit to the chosen climatology while keeping the balance between the variables in the course of analysis. The constraint varies selectively with the vertical level and the horizontal scale of the motion. The zonally averaged wind field from European Centre for Medium-Range Weather Forecasts Re-Analysis 40 (ERA-40) is used as a climatology field in the constraint. The constraint controls only the zonally averaged stratospheric long waves with total wave number less than 20 to fix the error of the large scale wind field in the stratosphere. The constrained 3dVar successfully suppresses the erroneous westerly in the stratospheric analysis promptly, and has been applied on the operational global 3dVar system at KMA.