• 제목/요약/키워드: experimental model

검색결과 18,898건 처리시간 0.045초

Walking load model for single footfall trace in three dimensions based on gait experiment

  • Peng, Yixin;Chen, Jun;Ding, Guo
    • Structural Engineering and Mechanics
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    • 제54권5호
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    • pp.937-953
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    • 2015
  • This paper investigates the load model for single footfall trace of human walking. A large amount of single person walking load tests were conducted using the three-dimensional gait analysis system. Based on the experimental data, Fourier series functions were adopted to model single footfall trace in three directions, i.e. along walking direction, direction perpendicular to the walking path and vertical direction. Function parameters such as trace duration time, number of Fourier series orders, dynamic load factors (DLFs) and phase angles were determined from the experimental records. Stochastic models were then suggested by treating walking rates, duration time and DLFs as independent random variables, whose probability density functions were obtained from experimental data. Simulation procedures using the stochastic models are presented with examples. The simulated single footfall traces are similar to the experimental records.

실험적으로 구한 MR 댐퍼의 개선된 Bouc-Wen 모델을 이용한 자동차 서스펜션 제어 (Vehicle Suspension Control Using an MR Damper of a Bouc-Wen Model Obtained from Experimental Studies)

  • 전형진;정슬
    • 제어로봇시스템학회논문지
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    • 제16권2호
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    • pp.151-157
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    • 2010
  • This paper presents the modelling of an MR damper system through extensive experimental studies. The hysteresis of the MR damper is modelled by using the improved Bouc-wen model. A test bed for experimental studies of measuring parameters of the MR damper is designed and implemented. Based on the experimental data, the Bouc-Wen Model is modified for the MR damper system. To check the modelling property, a vehicle suspension system is controlled using a PID controller for the verification of the MR damper model.

사출성형공정에서 CAE 기반 품질 데이터와 실험 데이터의 통합 학습을 통한 인공지능 품질 예측 모델 구축에 대한 연구 (A study on the construction of the quality prediction model by artificial neural intelligence through integrated learning of CAE-based data and experimental data in the injection molding process)

  • 이준한;김종선
    • Design & Manufacturing
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    • 제15권4호
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    • pp.24-31
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    • 2021
  • In this study, an artificial neural network model was constructed to convert CAE analysis data into similar experimental data. In the analysis and experiment, the injection molding data for 50 conditions were acquired through the design of experiment and random selection method. The injection molding conditions and the weight, height, and diameter of the product derived from CAE results were used as the input parameters for learning of the convert model. Also the product qualities of experimental results were used as the output parameters for learning of the convert model. The accuracy of the convert model showed RMSE values of 0.06g, 0.03mm, and 0.03mm in weight, height, and diameter, respectively. As the next step, additional randomly selected conditions were created and CAE analysis was performed. Then, the additional CAE analysis data were converted to similar experimental data through the conversion model. An artificial neural network model was constructed to predict the quality of injection molded product by using converted similar experimental data and injection molding experiment data. The injection molding conditions were used as input parameters for learning of the predicted model and weight, height, and diameter of the product were used as output parameters for learning. As a result of evaluating the performance of the prediction model, the predicted weight, height, and diameter showed RMSE values of 0.11g, 0.03mm, and 0.05mm and in terms of quality criteria of the target product, all of them showed accurate results satisfying the criteria range.

전기화학적 임피던스 Fitting 개선을 위한 전극/전해질 계면의 전기회로 모델 연구 (A Study on the Electrical Circuit Model of the Electrode/Electrolyte Interface for Improving Electrochemical Impedance Fitting)

  • 장종현;박정호
    • 전기학회논문지
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    • 제56권6호
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    • pp.1087-1091
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    • 2007
  • Exact impedance modeling of the electrode/electrolyte interface is important in bio-signal sensing electrode development. Therefore, the investigation of the equivalent circuit models for the interface has been pursued for a long time by several researchers. Previous circuit models fit the experimental results in limited conditions such as frequency range, type of electrode, or electrolyte. This paper describes a new electrical circuit model and its capability of fitting the experimental results. The proposed model consists of three resistors and two constant phase elements. Electrochemical impedance spectroscopy was used to characterize the interface for Au, Pt, and stainless steel electrode in 0.9% NaCl solution. Both the proposed model and the previous model were applied to fit the measured impedance results for comparison. The proposed model fits the experimental data more accurately than other models especially at the low frequency range, and it enables us to predict the impedance at very low frequency range, including DC, using the proposed model.

Ratcheting assessment of austenitic steel samples at room and elevated temperatures through use of Ahmadzadeh-Varvani Hardening rule

  • Xiaohui Chen;Lang Lang;Hongru Liu
    • Structural Engineering and Mechanics
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    • 제87권6호
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    • pp.601-614
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    • 2023
  • In this study, the uniaxial ratcheting effect of Z2CND18.12N austenitic stainless steel at room and elevated temperatures is firstly simulated based on the Ahmadzadeh-Varvani hardening rule (A-V model), which is embedded into the finite element software ABAQUS by writing the user material subroutine UMAT. The results show that the predicted results of A-V model are lower than the experimental data, and the A-V model is difficult to control ratcheting strain rate. In order to improve the predictive ability of the A-V model, the parameter γ2 of the A-V model is modified using the isotropic hardening criterion, and the extended A-V model is proposed. Comparing the predicted results of the above two models with the experimental data, it is shown that the prediction results of the extended A-V model are in good agreement with the experimental data.

Nonlinear finite element analysis of RC beams strengthened with CFRP strip against shear

  • Bulut, Nalan;Anil, Ozgur;Belgin, Cagatay M.
    • Computers and Concrete
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    • 제8권6호
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    • pp.717-733
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    • 2011
  • Strengthening of reinforced concrete (RC) members against shear that is one of the failure modes especially avoided by using carbon fiber reinforced polymer (CFRP) is widely used technique, which is studied at many experimental studies. However, conducting experimental studies are required more financial resources and laboratory facilities. In addition, along with financial resources, more time is needed in order to carry out comprehensive experimental studies. For these reasons, a verified finite element model that is tested with previous experimental studies can be used for reaching generalized results and investigating parameters that are not studied. For this purpose, previous experimental study results are used and "T" cross-sectioned RC beams strengthened with CFRP strips with insufficient shear strength are modeled by using ANSYS software. First, finite elements modeling of the previously tested RC beams are done, and then the computed results are compared with the experimental ones whether they are matched or not. As a result, the finite element model is verified. Later, analyses of the cases without any test results are done by using the verified model. Optimum CFRP strip spacing is determined with this verified finite element model, and compared with the experimental findings.

슬랙스 실루엣의 도형적 해석을 이용한 패턴 연구 (A Study on Pattern Using Geometric Interpretation of Stacks Silhouette)

  • 강석경;임원자
    • 한국의류학회지
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    • 제21권5호
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    • pp.807-820
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    • 1997
  • This exploratory research was intended to develop and test a slacks pattern based upon conic model. Data came from measurements of photograph of three subjects. Silhouette of slacks was close fit on waist and hip and loose under hip level. This three-dimensional form was modeled with truncated cones. This conic model was truncated by plane of the waist level, the abdomen level, the hip level, the crotch level and the ankle level parallel to the floor. Two models that have differences in back part of the model were tested. Drafted patterns from two models were taken for each subject. Drafted experimental pattern was operated for slacks pattern. The first step was to make sideseam. Parts over crotch level were moved to both sides. And then to make waistdarts. Experimental pattern had two darts each in front and back. Each experimental slacks was evaluated by sensory test to appearance and comfort by five judges. The results can be summarized as follows. 1) Appearance and comfort of experimental pattern were judged to be satisfactory. Especially these patterns were fitted we18 in waist darts front and back. So we evaluated that was proper pattern for slacks. 2) Model 2 was better in appearance than model 1. But Model 1 was more comfortable in non significant difference. This was supposed to be resulted from fit more closely of model 2. 3) considering preceding results, this geometric model based upon truncated cone was applicable for slacks pattern.

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Nonlinear numerical analyses of a pile-soil system under sinusoidal bedrock loadings verifying centrifuge model test results

  • Kim, Yong-Seok;Choi, Jung-In
    • Geomechanics and Engineering
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    • 제12권2호
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    • pp.239-255
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    • 2017
  • Various centrifuge model tests on the pile foundations were performed to investigate fundamental characteristics of a pile-soil-foundation system recently, but it is hard to find numerical analysis results of a pile foundation system considering the nonlinear behavior of soil layers due to the dynamic excitations. Numerical analyses for a pile-soil system were carried out to verify the experimental results of centrifuge model tests. Centrifuge model tests were performed at the laboratory applying 1.5 Hz sinusoidal base input motions, and nonlinear numerical analyses were performed utilizing a finite element program of P3DASS in the frequency domain and applying the same input motions with the intensities of 0.05 g~0.38 g. Nonlinear soil properties of soil elements were defined by Ramberg-Osgood soil model for the nonlinear dynamic analyses. Nonlinear numerical analyses with the P3DASS program were helpful to predict the trend of experimental responses of a centrifuge model efficiently, even though there were some difficulties in processing analytical results and to find out unintended deficits in measured experimental data. Also nonlinear soil properties of elements in the system can be estimated adequately using an analytical program to compare them with experimental results.

Education based on the health belief model to improve the level of physical activity

  • Khodaveisi, Masoud;Azizpour, Bahman;Jadidi, Ali;Mohammadi, Younes
    • 운동영양학회지
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    • 제25권4호
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    • pp.17-23
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    • 2021
  • [Purpose] This study aimed to investigate the effect of education based on the health belief model on the physical activity of the staff of the University of Medical Sciences. [Methods] This semi-experimental study was conducted on 130 university staff aged 25-50 years from the Hamadan University of Medical Sciences. Inclusion criteria were having at least 1 year of work experience, lack of acute and chronic physical and mental illnesses, and not using drugs that affect physical activity. The samples were randomly divided into two groups. The experimental group received three training sessions based on the health belief model. Before and 2 months after training, the control and experimental groups were evaluated via the following questionnaires: (1) demographic information questionnaire, (2) Health Belief Model Questionnaire, and (3) International Physical Activity Questionnaire. Finally, data were analyzed statistically. [Results] The training process resulted in a significant increase in the mean scores of the health belief model constructs in the experimental group, but changes in the control group were not significant. Self-efficacy was the strongest predictor of physical activity. [Conclusion] The health belief model is a useful model for improving individuals' understanding of the benefits of physical activity.

중국어 텍스트 분류 작업의 개선을 위한 WWMBERT 기반 방식 (A WWMBERT-based Method for Improving Chinese Text Classification Task)

  • 왕흠원;조인휘
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2021년도 춘계학술발표대회
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    • pp.408-410
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    • 2021
  • In the NLP field, the pre-training model BERT launched by the Google team in 2018 has shown amazing results in various tasks in the NLP field. Subsequently, many variant models have been derived based on the original BERT, such as RoBERTa, ERNIEBERT and so on. In this paper, the WWMBERT (Whole Word Masking BERT) model suitable for Chinese text tasks was used as the baseline model of our experiment. The experiment is mainly for "Text-level Chinese text classification tasks" are improved, which mainly combines Tapt (Task-Adaptive Pretraining) and "Multi-Sample Dropout method" to improve the model, and compare the experimental results, experimental data sets and model scoring standards Both are consistent with the official WWMBERT model using Accuracy as the scoring standard. The official WWMBERT model uses the maximum and average values of multiple experimental results as the experimental scores. The development set was 97.70% (97.50%) on the "text-level Chinese text classification task". and 97.70% (97.50%) of the test set. After comparing the results of the experiments in this paper, the development set increased by 0.35% (0.5%) and the test set increased by 0.31% (0.48%). The original baseline model has been significantly improved.