• Title/Summary/Keyword: feed-forward

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Active Vibration Control Using Piezostack Based Mount (압전작동기 마운트를 이용한 능동진동제어)

  • Nguyen, Vien-Quoc;Choi, Sang-Min;Paeng, Yong-Seok;Han, Young-Min;Choi, Seung-Bok;Moon, Seok-Jun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.4
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    • pp.386-392
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    • 2008
  • This paper presents active vibration control performance of a hybrid mount. The proposed hybrid mount is devised by adopting both piezostack as an active actuator and rubber as a passive element. After experimentally identifying actuating force characteristics of the piezostack and dynamic characteristics of the rubber, the hybrid mount was designed and manufactured. Subsequently, a vibration control system with a specific mass loading is constructed, and its governing equations of motion are derived. In order to actively attenuate vibration transmitted from the base, a feedforward controller is formulated and experimentally realized. Vibration control responses are then evaluated in time and frequency domains.

A Recommender System Model Using a Neural Network Based on the Self-Product Image Congruence

  • Kang, Joo Hee;Lee, Yoon-Jung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.44 no.3
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    • pp.556-571
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    • 2020
  • This study predicts consumer preference for social clothing at work, excluding uniforms using the self-product congruence theory that also establishes a model to predict the preference for recommended products that match the consumer's own image. A total of 490 Korean male office workers participated in this study. Participants' self-image and the product images of 20 apparel items were measured using nine adjective semantic scales (namely elegant, stable, sincere, refined, intense, luxury, bold, conspicuous, and polite). A model was then constructed to predict the consumer preferences using a neural network with Python and TensorFlow. The resulting Predict Preference Model using Product Image (PPMPI) was trained using product image and the preference of each product. Current research confirms that product preference can be predicted by the self-image instead of by entering the product image. The prediction accuracy rate of the PPMPI was over 80%. We used 490 items of test data consisting of self-images to predict the consumer preferences for using the PPMPI. The test of the PPMPI showed that the prediction rate differed depending on product attributes. The prediction rate of work apparel with normative images was over 70% and higher than for other forms of apparel.

A Study on Kinematics Modeling and Motion Control Algorithm Development in Joint for Vertical Type Articulated Robot Arma (수직다관절형 아암의 운동학적 모델링 및 관절공간 모션제어에 관한 연구)

  • Jo, Sang-Young;Kim, Min-Seong;Yang, Jun-Seok;Won, Jong-Beom;Han, Sung-Hyun
    • Journal of the Korean Society of Industry Convergence
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    • v.19 no.1
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    • pp.18-30
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    • 2016
  • In this paper, we propose a new technique to the design and real-time control of an adaptive controller for robotic manipulator based on digital signal processors. The Texas Instruments DSPs(TMS320C80) chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved Lyapunov second method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for a dual arm robot manipulator with eight joints. joint space and cartesian space.

Fast Face Gender Recognition by Using Local Ternary Pattern and Extreme Learning Machine

  • Yang, Jucheng;Jiao, Yanbin;Xiong, Naixue;Park, DongSun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.7
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    • pp.1705-1720
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    • 2013
  • Human face gender recognition requires fast image processing with high accuracy. Existing face gender recognition methods used traditional local features and machine learning methods have shortcomings of low accuracy or slow speed. In this paper, a new framework for face gender recognition to reach fast face gender recognition is proposed, which is based on Local Ternary Pattern (LTP) and Extreme Learning Machine (ELM). LTP is a generalization of Local Binary Pattern (LBP) that is in the presence of monotonic illumination variations on a face image, and has high discriminative power for texture classification. It is also more discriminate and less sensitive to noise in uniform regions. On the other hand, ELM is a new learning algorithm for generalizing single hidden layer feed forward networks without tuning parameters. The main advantages of ELM are the less stringent optimization constraints, faster operations, easy implementation, and usually improved generalization performance. The experimental results on public databases show that, in comparisons with existing algorithms, the proposed method has higher precision and better generalization performance at extremely fast learning speed.

AUTOMATIC DETECTION OF EPILEPTIFORM ACTIVITY USING WAVELET AND ARTIFICIAL NEURAL NETWORK (웨이브렛과 신경회로망을 이용한 간질 파형 자동 검출)

  • Park, H.S.;Park, C.H.;Lee, Y.H.;Lee, D.S.;Kim, S.I.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.05
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    • pp.358-361
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    • 1997
  • This paper describes a multichannel epileptic seizure detection algorithm based on wavelet transform(WT), artificial neural network(ANN) and expert system. First, through the WT, a small number of wavelet coefficients is used to represent the single channel epileptic spike. Next, 3-layer feed-forward network employing the error back propagation algorithm is trained and tested using parameters obtained above. Finally, 16 channel expert system which is based on clinical experience is introduced as a artifact rejection and reliable detection. The suggested algorithm was implemented on personal computer(PC). Two main events i.e., epileptiform and normal activities, were selected from 32 person's EEGs(normal: 20, seizure disorder: 12) in consensus among experts. The result was that WT reduced data input size and ANN detected 97 of the 100 EEGs containing definite spike - sensitivity of 97%. Expert rule system was capable of rejecting a wide variety of artifacts commonly found in EEG recordings. It also reduced false positive detections of ANN.

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A Study on the Determination of Linear Model and Linear Control of Biped Robot (이족로봇의 선형모델결정과 제어에 관한 연구)

  • Park, In-Gyu;Kim, Jin-Geol
    • Proceedings of the KIEE Conference
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    • 2000.11d
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    • pp.765-768
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    • 2000
  • Linearization of the biped dynamic equations and design of linear controller for the linearized equations are studied in this paper. The biped robot with inverted pendulum type trunk, used to stabilize the dynamic balancing of the biped robot during dynamic walking period, is modelled with 14 DOF and simulated. Despite of well defined linear control theories so far, the linear control methods was limited to the applications for a walking robot, because they have been inherently strong nonlinear properties, such as a modeling parameter uncertainties, external forces as noise, inertial and Coriolis terms by three dimensional modeling and so on. To linearize the nonlinear equations of motion of biped robot on MIMO and time varying linear equations of motion, 1st order Taylor series is used to formulate the linear equation. And a 2nd order numerical perturbation method Is used to approximate partial differential equations. Using the linearized equations of motion, a linear controller is designed by pole placement method with feed forward compensation. Using the obtained linearized equations and linear controller, the continuous walking simulation is performed.

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Predicting the buckling load of smart multilayer columns using soft computing tools

  • Shahbazi, Yaser;Delavari, Ehsan;Chenaghlou, Mohammad Reza
    • Smart Structures and Systems
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    • v.13 no.1
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    • pp.81-98
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    • 2014
  • This paper presents the elastic buckling of smart lightweight column structures integrated with a pair of surface piezoelectric layers using artificial intelligence. The finite element modeling of Smart lightweight columns is found using $ANSYS^{(R)}$ software. Then, the first buckling load of the structure is calculated using eigenvalue buckling analysis. To determine the accuracy of the present finite element analysis, a compression study is carried out with literature. Later, parametric studies for length variations, width, and thickness of the elastic core and of the piezoelectric outer layers are performed and the associated buckling load data sets for artificial intelligence are gathered. Finally, the application of soft computing-based methods including artificial neural network (ANN), fuzzy inference system (FIS), and adaptive neuro fuzzy inference system (ANFIS) were carried out. A comparative study is then made between the mentioned soft computing methods and the performance of the models is evaluated using statistic measurements. The comparison of the results reveal that, the ANFIS model with Gaussian membership function provides high accuracy on the prediction of the buckling load in smart lightweight columns, providing better predictions compared to other methods. However, the results obtained from the ANN model using the feed-forward algorithm are also accurate and reliable.

Shear Capacity of Reinforced Concrete Beams Using Neural Network

  • Yang, Keun-Hyeok;Ashour, Ashraf F.;Song, Jin-Kyu
    • International Journal of Concrete Structures and Materials
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    • v.1 no.1
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    • pp.63-73
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    • 2007
  • Optimum multi-layered feed-forward neural network (NN) models using a resilient back-propagation algorithm and early stopping technique are built to predict the shear capacity of reinforced concrete deep and slender beams. The input layer neurons represent geometrical and material properties of reinforced concrete beams and the output layer produces the beam shear capacity. Training, validation and testing of the developed neural network have been achieved using 50%, 25%, and 25%, respectively, of a comprehensive database compiled from 631 deep and 549 slender beam specimens. The predictions obtained from the developed neural network models are in much better agreement with test results than those determined from shear provisions of different codes, such as KBCS, ACI 318-05, and EC2. The mean and standard deviation of the ratio between predicted using the neural network models and measured shear capacities are 1.02 and 0.18, respectively, for deep beams, and 1.04 and 0.17, respectively, for slender beams. In addition, the influence of different parameters on the shear capacity of reinforced concrete beams predicted by the developed neural network shows consistent agreement with those experimentally observed.

Audio Event Classification Using Deep Neural Networks (깊은 신경망을 이용한 오디오 이벤트 분류)

  • Lim, Minkyu;Lee, Donghyun;Kim, Kwang-Ho;Kim, Ji-Hwan
    • Phonetics and Speech Sciences
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    • v.7 no.4
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    • pp.27-33
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    • 2015
  • This paper proposes an audio event classification method using Deep Neural Networks (DNN). The proposed method applies Feed Forward Neural Network (FFNN) to generate event probabilities of ten audio events (dog barks, engine idling, and so on) for each frame. For each frame, mel scale filter bank features of its consecutive frames are used as the input vector of the FFNN. These event probabilities are accumulated for the events and the classification result is determined as the event with the highest accumulated probability. For the same dataset, the best accuracy of previous studies was reported as about 70% when the Support Vector Machine (SVM) was applied. The best accuracy of the proposed method achieves as 79.23% for the UrbanSound8K dataset when 80 mel scale filter bank features each from 7 consecutive frames (in total 560) were implemented as the input vector for the FFNN with two hidden layers and 2,000 neurons per hidden layer. In this configuration, the rectified linear unit was suggested as its activation function.

Neural Network Modeling of PECVD SiN Films and Its Optimization Using Genetic Algorithms

  • Han, Seung-Soo
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.1 no.1
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    • pp.87-94
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    • 2001
  • Silicon nitride films grown by plasma-enhanced chemical vapor deposition (PECVD) are useful for a variety of applications, including anti-reflecting coatings in solar cells, passivation layers, dielectric layers in metal/insulator structures, and diffusion masks. PECVD systems are controlled by many operating variables, including RF power, pressure, gas flow rate, reactant composition, and substrate temperature. The wide variety of processing conditions, as well as the complex nature of particle dynamics within a plasma, makes tailoring SiN film properties very challenging, since it is difficult to determine the exact relationship between desired film properties and controllable deposition conditions. In this study, SiN PECVD modeling using optimized neural networks has been investigated. The deposition of SiN was characterized via a central composite experimental design, and data from this experiment was used to train and optimize feed-forward neural networks using the back-propagation algorithm. From these neural process models, the effect of deposition conditions on film properties has been studied. A recipe synthesis (optimization) procedure was then performed using the optimized neural network models to generate the necessary deposition conditions to obtain several novel film qualities including high charge density and long lifetime. This optimization procedure utilized genetic algorithms, hybrid combinations of genetic algorithm and Powells algorithm, and hybrid combinations of genetic algorithm and simplex algorithm. Recipes predicted by these techniques were verified by experiment, and the performance of each optimization method are compared. It was found that the hybrid combinations of genetic algorithm and simplex algorithm generated recipes produced films of superior quality.

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