• 제목/요약/키워드: experimental techniques

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첨단 유동가시화 기술을 이용한 수치해석 검증용 실험 (EXPERIMENTS FOR VALIDATING NUMERICAL ANALYSIS USING ADVANCED FLOW VISUALIZATION TECHNOLOGIES)

  • 이상준
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2008년도 학술대회
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    • pp.14-17
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    • 2008
  • Recently, several advanced flow visualization techniques such as Particle Image Velocimetry (PIV) including stereo PIV, holographic PIV, and dynamic PIV have been developed. These advanced techniques have strong potential as the experimental technology which can be used for verifying numerical simulation. In addition, there would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the basic research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is difficult for conventional methods to observe most complicated nano- and bio-fluidic phenomena. In this paper, the basic principle of these advanced visualization techniques and their practical applications which cannot be resolved by conventional methods, such as flow in automotive HVAC system, ship and propeller wake, three-dimensional flow measurement in micro-conduits, and flow around a circulating cylinder will be introduced.

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첨단 유동가시화 기술을 이용한 수치해석 검증용 실험 (EXPERIMENTS FOR VALIDATING NUMERICAL ANALYSIS USING ADVANCED FLOW VISUALIZATION TECHNOLOGIES)

  • 이상준
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2008년 추계학술대회논문집
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    • pp.14-17
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    • 2008
  • Recently, several advanced flow visualization techniques such as Particle Image Velocimetry (PIV) including stereo PIV, holographic PIV, and dynamic PIV have been developed. These advanced techniques have strong potential as the experimental technology which can be used for verifying numerical simulation. In addition, there would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the basic research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is difficult for conventional methods to observe most complicated nano- and bio-fluidic phenomena. In this paper, the basic principle of these advanced visualization techniques and their practical applications which cannot be resolved by conventional methods, such as flow in automotive HVAC system, ship and propeller wake, three-dimensional flow measurement in micro-conduits, and flow around a circulating cylinder will be introduced.

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Compensation techniques for experimental errors in real-time hybrid simulation using shake tables

  • Nakata, Narutoshi;Stehman, Matthew
    • Smart Structures and Systems
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    • 제14권6호
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    • pp.1055-1079
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    • 2014
  • Substructure shake table testing is a class of real-time hybrid simulation (RTHS). It combines shake table tests of substructures with real-time computational simulation of the remaining part of the structure to assess dynamic response of the entire structure. Unlike in the conventional hybrid simulation, substructure shake table testing imposes acceleration compatibilities at substructure boundaries. However, acceleration tracking of shake tables is extremely challenging, and it is not possible to produce perfect acceleration tracking without time delay. If responses of the experimental substructure have high correlation with ground accelerations, response errors are inevitably induced by the erroneous input acceleration. Feeding the erroneous responses into the RTHS procedure will deteriorate the simulation results. This study presents a set of techniques to enable reliable substructure shake table testing. The developed techniques include compensation techniques for errors induced by imperfect input acceleration of shake tables, model-based actuator delay compensation with state observer, and force correction to eliminate process and measurement noises. These techniques are experimentally investigated through RTHS using a uni-axial shake table and three-story steel frame structure at the Johns Hopkins University. The simulation results showed that substructure shake table testing with the developed compensation techniques provides an accurate and reliable means to simulate the dynamic responses of the entire structure under earthquake excitations.

디모자익킹 기술 개발을 위한 신규 맥매스터 영상 데이터에 대한 해석 (Analysis on the new McMaster image dataset to develop demosaicking techniques)

  • 유훈
    • 한국정보통신학회논문지
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    • 제16권2호
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    • pp.344-349
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    • 2012
  • 본 논문에서는 디모자익킹 기술 개발에서 신규 맥매스터 영상 데이터에 대한 실험을 진행하고 그에 따른 해석 결과를 제공한다. 디모자익킹 기술 개발을 위해서 사용되는 실험 영상으로 현재까지 가장 알려져 있는 데이터는 코닥 영상이다. 하지만 최근 신규 영상 데이터가 개발됨으로써 이전과는 다른 디모자익킹 실험 결과를 보여주고 있다. 따라서, 본 논문에서는 코닥 영상과 맥매스터 영상에 대한 통계적 특성을 실험, 분석 하고 비교함으로써 신규 실험 영상이 어떤 특징을 갖는지에 대해서 해석한다. 또한 실험 결과와 해석은 맥매스터 영상이 디모자익킹 기술 개발에 실험 영상으로써 가치가 있음을 보여주며, 향후 개발될 디모자익킹 기술에 대한 기초 자료로 활용될 것으로 기대된다.

A STATISTICAL ANALYSIS METHOD FOR ESTIMATING GROUNDWATER CONTAMINANT CONCENTRATION

  • LEE, YOUNG CHEON
    • 호남수학학술지
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    • 제26권1호
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    • pp.87-103
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    • 2004
  • A practical estimation method for groundwater contaminant concentration is introduced. Using geostatistical techniques and symmetry, experimental variograms show significant improved correlation compared with those from conventional techniques. Numrical experiments are performed using a field data set.

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An Experimental Investigation of the Application of Artificial Neural Network Techniques to Predict the Cyclic Polarization Curves of AL-6XN Alloy with Sensitization

  • Jung, Kwang-Hu;Kim, Seong-Jong
    • Corrosion Science and Technology
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    • 제20권2호
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    • pp.62-68
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    • 2021
  • Artificial neural network techniques show an excellent ability to predict the data (output) for various complex characteristics (input). It is primarily specialized to solve nonlinear relationship problems. This study is an experimental investigation that applies artificial neural network techniques and an experimental design to predict the cyclic polarization curves of the super-austenitic stainless steel AL-6XN alloy with sensitization. A cyclic polarization test was conducted in a 3.5% NaCl solution based on an experimental design matrix with various factors (degree of sensitization, temperature, pH) and their levels, and a total of 36 cyclic polarization data were acquired. The 36 cyclic polarization patterns were used as training data for the artificial neural network model. As a result, the supervised learning algorithms with back-propagation showed high learning and prediction performances. The model showed an excellent training performance (R2=0.998) and a considerable prediction performance (R2=0.812) for the conditions that were not included in the training data.

A PRACTICAL ESTIMATION METHOD FOR GROUNDWATER LEVEL ELEVATIONS

  • Cho, Choon-Kyung;Kang, Sung-Kwon
    • 대한수학회지
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    • 제34권4호
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    • pp.927-947
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    • 1997
  • A practical estimation method for groundwater level elevations is introduced. Using geostatistical techniques with drift, averaging process and ratio, experimental variograms show significant improved coorelation compared with those from conventional techniques. The estimation method is applied to a field experimental data set.

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SIMULATION OF EXPERIMENTAL VISUALIZATION METHODS FOR COMPUTATIONAL FLUID DYNAMICS RESEARCH

  • TAMURA Y.;FUJII K.
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 1995년도 창립기념학술대회
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    • pp.44-68
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    • 1995
  • In the present paper, visualization techniques in fluid dynamic experiments such as Schlieren photograph are numerically simulated so that the same output as the experimental flow visualization can be obtained from the computed results for the fair comparison. Numerical methods to simulate optical visualizations, that are Schlieren photograph, shadowgraph and interferogram, are considered. Some examples of pictures obtained by the present methods show the importance of the simulations of visualization techniques for the correct comparisons of the computations and experiments.

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골반 변위가 있는 환자에서 추나 치료군과 자가 MET 병행군의 교정 정도 비교 연구 : 무작위 대조 연구 (The comparative study between the effect of Chuna manual treatment and Chuna manual treatment with self muscle energy techniques on patients with pelvic malposition : A Randomized, Controlled, Trial)

  • 윤용일;허석원;배영춘;정범환;조주현
    • 척추신경추나의학회지
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    • 제10권1호
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    • pp.75-86
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    • 2015
  • Objectives : The purpose of this study is to compare the effect of Chuna manual treatment and Chuna manual treatment with self muscle energy techniques on patients with pelvic malposition Methods : Random allocation was done. We used Chuna manual treatment to control group and Chuna manual treatment with self muscle energy techniques to experimental group. These patient's pelvic malposition were checked by Leg length analysis, measuring Innominate measurement length, obturator foramen size and height of femur head. Results : 1)After the 3 weeks treatment, patients' inequality of leg length and Innominate measurement length were significantly reduced. 2)There was no significant difference between control group and experimental group. Conclusions : Chuna manual treatment and Chuna manual treatment with self muscle energy techniques are considered to be effective and useful in patients with pelvic malposition. But there was no significant difference between control group and experimental group.