• Title/Summary/Keyword: modified technique

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High accuracy position control of pneumatic rodless cylinder using LVQNN (LVQNN을 이용한 공압 로드리스 실린더의 고정도 위치제어)

  • 표성만;정민화;안경관;이병룡;양순용
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1012-1017
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    • 2003
  • The development of a fast, accurate, and inexpensive position-controlled pneumatic actuator that may be applied to a variety of practical positioning applications with various external loads is described in this paper. A novel modified pulso width modulation (MPWM) valve pulsing algorithm allows on/off solenoid valves to be used in place of costly servo valves. A comparison between the system response of standard PWM technique and that of the novel modified PWM technique shows that the control performance is significantly increased. A state feedback controller with position, velocity and acceleration feedback is successfully implemented as the continuous controller. Switching algorithm of control parameter using learning vector quantization neural network (LVQNN) is newly proposed. which estimates the external loads of the pneumatic actuator. The effectiveness of the proposed control algorithms are demonstrated through experiments with various loads.

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Development of Planning Indicators in Rural Village for Realization of Low Carbon Society (저탄소사회 실현을 위한 농촌마을 계획지표 개발)

  • Kim, Eun-Ja;Ko, Ah-La;Lee, Jeung-Won;Kim, Sang-Bum
    • Journal of Korean Society of Rural Planning
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    • v.17 no.1
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    • pp.29-42
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    • 2011
  • The Purpose of this study is to develop indicators for low carbon planning in rural village. We made two indicators for inland area and waterside area to consider regional disparities. To develop indicators, a draft of the indicators was estimated with collected research materials and 52 experts reviewed this draft three times with Modified Delphi Technique to check the validity and revise the draft. As a result, the inland indicators were settled with 4 domains 8 items 20 indicators and the waterside indicators were 4 domains 8 items 22 indicators. The final indicators will be used to realize low carbon rural village planning in future which the government is pushing forward with construction of six-hundred low carbon green village.

Intelligent Control of Pneumatic Actuator using On/Off Valve (On/Off 밸브를 이용한 공압 실린더의 지능제어)

  • 안경관;표성만;송인성;이병룡;양순용
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.8
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    • pp.86-93
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    • 2003
  • The development of a fast, accurate, and inexpensive position-controlled pneumatic actuator that may be applied to a variety of practical positioning applications with various external loads is described in this paper. A novel modified pulse width modulation (MPWM) valve pulsing algorithm allows on/off solenoid valves to be used in place of costly servo valves. A comparison between the system response of standard PWM technique and that of the novel modified PWM technique shows that the control performance is significantly increased. A state feedback controller with position, velocity and acceleration feedback is successfully implemented as the continuous controller. Switching algorithm of control parameter using learning vector quantization neural network (LVQNN) is newly proposed, which estimates the external loads of the pneumatic actuator. The effectiveness of the proposed control algorithms are demonstrated through experiments with various loads.

Iterative Tuning of PID Controller by Fuzzy Indirect Reasoning and a Modified Zigler-Nichols Method (퍼지 간접추론법과 수정형 지글러-니콜스법에 의한 비례-적분-미분 제어기의 점진적 동조)

  • Kim, S.D.
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.5
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    • pp.74-83
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    • 1996
  • An iterative tuning technique is derived for PID controllers which are widely used in industries. The tuning algorithm is based upon a fuzzy indirect reasoning method and an iterative technique. The PID gains for the first tuning action are determined by a method which is modified from the Ziegler-Nichols step response method. The first PID gains are determined to obtain a control performance so close to a design performance that the following tuning process can be made effectively. The design paramaters are given as time-domain variables which human is familiar with. The results of simulation studies show that the proposed tuning method can produce an effective tuning for arbitrary design performances.

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Analysis of Shear Damage Behaviour of Reinforced Concrete Beams using Modified Compression Field Theory (철근콘크리트보의 전단피로손상거동에 대한 수정압축장이론을 이용한 해석기법)

  • 한승환;오병환
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.552-557
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    • 1997
  • In this study, a quantitative analysis technique for the damage process of reinforced concrete beams under repeated shear loading is proposed, which can express the progressively increasing strain and stiffness reduction. The analysis technique is mainly based on the modified compression field theory and scalar damage concept. which describe the strain and stress configuration in the shear zone by considering the 2-dimensional effect, and express the degradation of principal compressive strut by cyclic strain increment, secant modulus decrement, and modifying the parabolic stress strain relationship. The analysis of the response of RC beams under repeated shear-flexure loading has been carried out and compared with the experimental results. The present theory may efficiently be used to evaluate the deflection and strain accumulation under repeated loadings.

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Study of the Photo-alignment Technique through the Surface Modification

  • Song, Dong-Mee;Shin, Dong-Myung
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.197-198
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    • 2000
  • A surface-assisted photo-control of the liquid crystal (LC) alignment has been achieved by modifying the topmost surface of the polyimide film with photo-reactive molecules. Recently, photo-alignment technique using a thin film of poly(vinyl cinnamates) have been reported. However their commercial potentiality is limited by their low thermal stability. To enhance thermal stability, we synthesized the chalcone derivatives as the photo-reactive molecules and introduced the materials on the surface-modified polyimide film.. We identified that the photo-chemical reaction of the chalcone derivatives occur in few minutes with irradiation of UV light. The photo-alignment characteristics of the modified polyimide films treated by polarized UV light and their LC cells are investigated as a function of exposure dose.

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CT Guided Transaortic Celiac Plexus Neurolysis (CT감시하의 경대동맥 접근법에 의한 복강 신경총 차단)

  • Chung, Mi-Young;Lee, Hae-Giu;Lee, Chul-Woo
    • The Korean Journal of Pain
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    • v.4 no.1
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    • pp.37-41
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    • 1991
  • Celiac Plexus neurolysis (C. P. N) has been commonly used to treat malignant pain of the abdominal area that is intractable. It relieves the pain effectively instead of using massive systemic narcotic analgesics. C. P. N. with modified transaortic technique was performed under C-T guidance, in which a single needle was advanced from a left posterior paramedian approach through the aorta in order to inject anesthetic agents directly into the celiac plexus. There was marked pain relief without any hemorrhagic and neurological or other complications. We found this modified transaortic method of C. P. N. to be very effective, safe and easy to perform compared with the classic two needle technique.

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A Parallel Operation of DC/DC Converter for suitable Photovoltaics System (태양광 발전에 적합한 DC/DC 컨버터의 병렬운전)

  • Kim Byeong-Woo;Park Sung-Jun;Moon Chae-Ju;Nam Hae-Kon;Kim Cheul-U;Kim Jong-Dal
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.1498-1500
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    • 2004
  • A novel technique for efficiently extracting maximum power from PV panels is proposed, consisting of a modified buck-boost converter, witch is controlled by a DSP. A variation of the proposed MPPT technique is directly use the modified buck-boost converter current reference as a control parameter. Also 4 parallel boost converters have division of load. A theoretical analysis of the proposed converter is performed and compared with experimental results obtained from a 1k[W] prototype solar panel under a controlled experimental setup.

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Efficient Language Model based on VCCV unit for Sentence Speech Recognition (문장음성인식을 위한 VCCV 기반의 효율적인 언어모델)

  • Park, Seon-Hui;No, Yong-Wan;Hong, Gwang-Seok
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.836-839
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    • 2003
  • In this paper, we implement a language model by a bigram and evaluate proper smoothing technique for unit of low perplexity. Word, morpheme, clause units are widely used as a language processing unit of the language model. We propose VCCV units which have more small vocabulary than morpheme and clauses units. We compare the VCCV units with the clause and the morpheme units using the perplexity. The most common metric for evaluating a language model is the probability that the model assigns the derivative measures of perplexity. Smoothing used to estimate probabilities when there are insufficient data to estimate probabilities accurately. In this paper, we constructed the N-grams of the VCCV units with low perplexity and tested the language model using Katz, Witten-Bell, absolute, modified Kneser-Ney smoothing and so on. In the experiment results, the modified Kneser-Ney smoothing is tested proper smoothing technique for VCCV units.

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Time Harmonic interactions in the axisymmetric behaviour of transversely isotropic thermoelastic solid using New M-CST

  • Lata, Parveen;Kaur, Harpreet
    • Coupled systems mechanics
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    • v.9 no.6
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    • pp.521-538
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    • 2020
  • The present study is concerned with the thermoelastic interactions in a two dimensional homogeneous, transversely isotropic thermoelastic solid with new modified couple stress theory without energy dissipation and with two temperatures in frequency domain. The time harmonic sources and Hankel transform technique have been employed to find the general solution to the field equations.Concentrated normal force, normal force over the circular region, thermal point source and thermal source over the circular region have been taken to illustrate the application of the approach. The components of displacements, stress, couple stress and conductive temperature distribution are obtained in the transformed domain. The resulting quantities are obtained in the physical domain by using numerical inversion technique. Numerically simulated results are depicted graphically to show the effect of angular frequency on the resulted quantities.