• Title/Summary/Keyword: Constraint Effect

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Robust speed control of DC motor using Expert Hybrid controller (전문가 제어기를 이용한 직류 전동기의 강인 제어)

  • Cho, Hyeon-Seob;Oh, Hun;Jeon, Jeong-Chay;Ryu, In-Ho
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2799-2801
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    • 2000
  • Robust control for DC motor is needed according to the highest precision of industrial automation. However, when a motor control system with PID controller has an effect of load disturbance, it is very difficult to guarantee the robustness of control system. In this paper, PID-Expert hybrid control method for motor control system as a compensation method solving this problem is presented. If PID control system is stable, the Expert controller is idle. if the error hits the boundary of the constraint. the Expert controller begins operation to force the error back to the constraint set. The disturbance effect decrease remarkably, robust speed control of DC motor using PID-Expert Hybrid controller is demonstrated by the simulation.

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Expert Supervisory Control for PID Control System (PID 제어시스템을 위한 전문가 관리 제어)

  • Cho, Hyun-Seob
    • Proceedings of the KAIS Fall Conference
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    • 2008.05a
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    • pp.192-195
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    • 2008
  • Robust control for DC motor is needed according to the highest precision of industrial automation. However, when a motor control system with PID controller has an effect of load disturbance, it is very difficult to guarantee the robustness of control system. In this paper, PID-Expert hybrid control method for motor control system as a compensation method solving this problem is presented. If PID control system is stable, the Expert controller is idle. if the error hits the boundary of the constraint, the Expert controller begins operation to force the error back to the constraint set. The disturbance effect decrease remarkably, robust speed control of DC motor using PID-Expert Hybrid controller is demonstrated by the simulation.

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A Review of the Modified Constraint Induced Movement Therapy in Stroke Patients (뇌졸중 환자에게 적용된 수정된 강제유도 운동치료에 대한 고찰)

  • Lee, Jong-Min
    • Therapeutic Science for Rehabilitation
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    • v.2 no.2
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    • pp.5-20
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    • 2013
  • Constraint Induced Movement Therapy(CIMT) is intense in that patient's unaffected arm is restrained for 90% of waking hours during a two-week period while they also participate in activity sessions using the affected arm for 6 hours/day. However CIMT showed that an issue for applying it to clinics of patients with stroke, and then modified constraint induced movement therapy(mCIMT) was designed to minimize the issue. Application on mCIMT for the patients has been studied in various ways. As a result, it has proved the effect on functional improvement of patients with stroke through methods such as MAL, FMA, WMFT, ARAT, FIM, SIS and so forth. It's considered that modified constraint induced movement therapy can be useful applied on clinical experiments of occupational therapy, as it is a way of treatment of upper extremity function, activities of daily living and an improvement of the quality of life for stroke patients.

Crack-tip Stress Field of Fully Circumferential Surface Cracked Pipe Under Combined Tension and Thermal Loads (원주방향 부분 관통 균열이 존재하는 직관에 인장하중과 열하중의 복합하중이 가해지는 경우의 균열 선단 응력장)

  • Je, Jin Ho;Kim, Dong Jun;Kim, Yun Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.11
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    • pp.1207-1214
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    • 2014
  • Under excessive plasticity, the fracture toughness of a material depends on its size and geometry. Under fully yielded conditions, the stresses in a material near its crack tip are not unique but rather depend on the geometry. Therefore, the single-parameter J-approach is limited to a high-constraint crack geometry. The JQ theory has been proposed for establishing the crack geometry constraints. This approach assumes that the crack-tip fields have two degrees of freedom. In this study, the crack-tip stress field of a fully circumferential surface-cracked pipe under combined loads is investigated on the basis of the JQ theory by using finite element analysis. The combined loads are a tensile axial force and the thermal gradient in the radial direction. Q-stresses of the crack geometry and its loading state are used to determine the constraint effects. The constraint effects of secondary loading are found to be greater than those of primary loading. Therefore, thermal shock is believed to be the most severe loading condition of constraint effects.

The Effects of Constraint-induced Movement Therapy on Affected Upper Limb Functions in Patients with Hemiplegia (뇌졸중 후 편마비 환자의 건측억제-환측유도 운동이 환측 상지기능에 미치는 효과)

  • Yoo, Gwang-Soo;Bae, Joung-Hee
    • Research in Community and Public Health Nursing
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    • v.17 no.4
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    • pp.482-491
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    • 2006
  • Purpose: Hemiplegia patients who were attacked by a stroke suffer from hemiplegic disabilities as well as motor disabilities. For them, rehabilitation cure is being carried out broadly. However, it is not enough for them to use the upper extremity than the lower extremity. For the use of the upper extremity, we examined the effect of constraint-induced movement therapy developed in this research on patients who experienced a stroke following hemiplegia. Method: For this study we selected 36 stroke patients who were registered at the community health center through accidental sampling, and assigned 21 of them to the experimental group, and 15 to the control group. The experimental group had constraint-induced movement therapy for 5 days and 7 hours a day from 9 to o'clock in the morning 9 to 4 o'clock in the afternoon 4 including warmup exercise and main exercise in the rehabilitation room, whereas the control group were restricted. Result: As a result of constraint-induced movement therapy, affected side elbow joint flexion range, side shoulder joint extension range and side shoulder joint of the flexion range of motions increased obviously in the experimental group compared to those in the control group. Conclusion: The result above clearly shows that constraint-induced movement therapy is an effective intervention for the rehabilitation of hemiplegia patients in increasing affected side elbow joint of the flexion range of motion, the shoulder joint extension, and the increase of flexion range of motion.

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Evaluation of Pressure-Temperature Limit Curve for the Safe Operation of an RFV based on 3-D Finite Element Analyses (유한요소해석을 이용한 원자로용기 압력-온도 한계곡선의 평가)

  • Lee, Taek-Jin;Park, Yun-Won;Lee, Jin-Ho;Choe, Jae-Bung;Kim, Yeong-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.10
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    • pp.1567-1574
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    • 2001
  • In order to operate an RPV safely it is necessary to keep the pressure-temperature (P-T) limit during the heatup and cooldown process. While the ASME Code provides the P-T limit curve for safe operation, this limit curve has been prepared under conservative assumptions In this paper the effects of conservative assumptions involved in the P-T limit curve specified in the ASME Code Sec. XI were investigated. Three different parameters the crack depth the cladding thickness and the cooling rate, were reviewed based on 3-D finite element analyses. Also the constraint effect on P-T limit curve generation was investigated based on J- T approach. It was shown that the crack depth and the constraint effect change the safe region in P-T limit curve significantly Therefore it is recommended to prepare a more precise P-T limit curve based on finite element analysis to obtain P-T limit for safe operation of an RPV.

Understanding the Continuance Intention of Knowledge Contribution in Q&A Virtual Communities: Focused on Moderating Effect of Personal Involvement (Q&A 가상 커뮤니티에서 지속적인 지식 기여에 영향을 미치는 요인: 개인적 관여도의 조절효과를 중심으로)

  • Zhao, Li;Jung, Chul-Ho
    • Journal of Information Technology Applications and Management
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    • v.28 no.6
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    • pp.117-132
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    • 2021
  • Based on the core value of the Q&A community, the contribution of knowledge and information has a great impact on users' community evaluation. As a small social group, the relationships and interactions among community members are quickly formed through information technology. As such, the cognitive evaluation of the relationship between community members will have an impact on the intention of information contribution. This research builds on the previous research based on the social exchange theory and establishes a dual model of swift guanxi in examining the relationship between guanxi and continuous knowledge contribution. In the current study, 305 survey questionnaires were used and 249 valid questionnaires were used for analysis. The analysis results are as follows: First, information support has a positive impact on dedication-based swift guanxi. While hypothesis between information support and constraint-based swift guanxi was not be supported. Second, emotional support has a positive impact on the formation of swift guanxi from a dual perspective. Third, the swift guanxi from the dual perspective has a positive impact on the intention of continuous knowledge contribution. Finally, although personal involvement has an adjustment effect, it is a downward adjustment effect, hypotheses are not supported. The current study offers theoretical and practical implications in field of knowledge management, specifically knowledge contribution in the virtual community.

The Effect of Arm Swing on Gait in Post-Stroke Hemiparesis (팔 흔들기가 뇌졸중으로 인한 편마비 환자의 보행에 미치는 영향)

  • Kim, Jin-Seop;Kwon, Oh-Hyoun
    • Journal of the Korean Society of Physical Medicine
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    • v.7 no.1
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    • pp.95-101
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    • 2012
  • Purpose : The purpose of this study was to investigate the variations in gait parameters according to arm swing use in post stroke hemiparesis. Methods : Sixteen patients participated in this study and walked at self-selected speeds on a Rs-scan systems. The were randomly assigned conditions: self-selected arm swing, constraint arm swing, emphasis arm swing. Results : In the comparison of parameters in each trial, both affected step length, non affected step length, affected stride length, non affected stride length, affected single support time, and non affected single support time were significantly increased and double support time was significantly decrease in emphasis arm swing when compared with both self-selected arm swing and constraint arm swing(p<.05). However, Asymmetrical ratio was significantly increased in both emphasis arm swing and self-selected arm swing when compared constraint arm swing(p<.05). Conclusion : Therefore, In this study, gait rehabilitation of patients with hemiplegia depending on what you need to apply the arm swing is considered.

Analysis of Cleavage Fracture Toughness of PCVN Specimens Based on a Scaling Model (PCVN 시편 파괴인성의 균열 깊이 영향에 대한 Scaling 모델 해석)

  • Park, Sang-Yun;Lee, Ho-Jin;Lee, Bong-Sang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.4
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    • pp.409-416
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    • 2009
  • Standard procedures for a fracture toughness testing require very severe restrictions for the specimen geometry to eliminate a size effect on the measured properties. Therefore, the used standard fracture toughness data results in the integrity assessment being irrationally conservative. However, a realistic fracture in general structures, such as in nuclear power plants, may develop under the low constraint condition of a large scale yielding with a shallow surface crack. In this paper, cleavage fracture toughness tests have been made on side-grooved PCVN (precracked charpy V-notch) type specimens (10 by 10 by 55 mm) with various crack depths. The constraint effects on the crack depth ratios were evaluated quantitatively by the developed scaling method using the 3-D finite element method. After the fracture toughness correction from scaling model, the statistical size effects were also corrected according to the standard ASTM E 1921 procedure. The results were evaluated through a comparison with the $T_0$ of the standard CT specimen. The corrected $T_0$ for all of the PCVN specimens showed a good agreement to within $5.4^{\circ}C$ regardless of the crack depth, while the averaged PCVN $T_0$ was $13.4^{\circ}C$ higher than the real CT test results.

PID-Supervision Hybrid Controller for Robust Control of DC Motor (DC 전동기의 강인 제어를 위한 PID-관리 복합형 제어기)

  • Jeon, Jeong-Chay;Oh, Hun;Park, Wal-Seo;Cho, Hyeon-Seob;Ryu, In-Ho
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.244-246
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    • 1998
  • Robust control for DC motor is needed according to the highest precision of industrial automation. However when a motor control system with PID controller has an effect of load disturbance, it is very difficult to guarantee the robustness of control system. As a compensation method solving this problem, in this paper, PID-supervision hybrid control method for motor control system is presented. If the PID control system (without the supervisory controller) is stable in the sense that the error is inside the constraint set, the supervisory control is idle. If the error hits the boundary of the constraint, the supervisory controller begins operation to force the error back to the constraint set. We prove that the PID-supervision hybrid control system is globally stable in the sense that the error is guaranteed to be within the tolerance limits specified by the system designer.

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