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  • Open Access


    High-Precision Time Delay Estimation Based on Closed-Form Offset Compensation

    Yingying Li1, Hang Jiang1, Lianjie Yu1, Jianfeng Li1,2,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.3, pp. 2123-2136, 2023, DOI:10.32604/cmes.2022.021407

    Abstract To improve the estimation accuracy, a novel time delay estimation (TDE) method based on the closed-form offset compensation is proposed. Firstly, we use the generalized cross-correlation with phase transform (GCC-PHAT) method to obtain the initial TDE. Secondly, a signal model using normalized cross spectrum is established, and the noise subspace is extracted by eigenvalue decomposition (EVD) of covariance matrix. Using the orthogonal relation between the steering vector and the noise subspace, the first-order Taylor expansion is carried out on the steering vector reconstructed by the initial TDE. Finally, the offsets are compensated via simple least squares (LS). Compared to other… More >

  • Open Access


    An Adaptive Neuro-Fuzzy Inference System to Improve Fractional Order Controller Performance

    N. Kanagaraj*

    Intelligent Automation & Soft Computing, Vol.35, No.3, pp. 3213-3226, 2023, DOI:10.32604/iasc.2023.029901

    Abstract The design and analysis of a fractional order proportional integral derivate (FOPID) controller integrated with an adaptive neuro-fuzzy inference system (ANFIS) is proposed in this study. A first order plus delay time plant model has been used to validate the ANFIS combined FOPID control scheme. In the proposed adaptive control structure, the intelligent ANFIS was designed such that it will dynamically adjust the fractional order factors (λ and µ) of the FOPID (also known as PIλDµ) controller to achieve better control performance. When the plant experiences uncertainties like external load disturbances or sudden changes in the input parameters, the stability… More >

  • Open Access


    Time Delay Estimation in Radar System using Fuzzy Based Iterative Unscented Kalman Filter

    T. Jagadesh1,2, B. Sheela Rani3,*

    Computer Systems Science and Engineering, Vol.44, No.3, pp. 2569-2583, 2023, DOI:10.32604/csse.2023.027239

    Abstract RSs (Radar Systems) identify and trace targets and are commonly employed in applications like air traffic control and remote sensing. They are necessary for monitoring precise target trajectories. Estimations of RSs are non-linear as the parameters TDEs (time delay Estimations) and Doppler shifts are computed on receipt of echoes where EKFs (Extended Kalman Filters) and UKFs (Unscented Kalman Filters) have not been examined for computations. RSs, certain times result in poor accuracies and SNRs (low signal to noise ratios) especially, while encountering complicated environments. This work proposes IUKFs (Iterated UKFs) to track online filter performances while using optimization techniques to… More >

  • Open Access


    Multi-Classification and Distributed Reinforcement Learning-Based Inspection Swarm Offloading Strategy

    Yuping Deng1, Tao Wu1, Xi Chen2,*, Amir Homayoon Ashrafzadeh3

    Intelligent Automation & Soft Computing, Vol.34, No.2, pp. 1157-1174, 2022, DOI:10.32604/iasc.2022.022606

    Abstract In meteorological and electric power Internet of Things scenarios, in order to extend the service life of relevant facilities and reduce the cost of emergency repair, the intelligent inspection swarm is introduced to cooperate with monitoring tasks, which collect and process the current scene data through a variety of sensors and cameras, and complete tasks such as emergency handling and fault inspection. Due to the limitation of computing resources and battery life of patrol inspection equipment, it will cause problems such as slow response in emergency and long time for fault location. Mobile Edge Computing is a promising technology, which… More >

  • Open Access


    Energy-Efficient Cluster in Wireless Sensor Network Using Life Time Delay Clustering Algorithms

    V. Kumar1,*, N. Jayapandian2, P. Balasubramanie3

    Computer Systems Science and Engineering, Vol.43, No.1, pp. 77-86, 2022, DOI:10.32604/csse.2022.023481

    Abstract Through Wireless Sensor Networks (WSN) formation, industrial and academic communities have seen remarkable development in recent decades. One of the most common techniques to derive the best out of wireless sensor networks is to upgrade the operating group. The most important problem is the arrangement of optimal number of sensor nodes as clusters to discuss clustering method. In this method, new client nodes and dynamic methods are used to determine the optimal number of clusters and cluster heads which are to be better organized and proposed to classify each round. Parameters of effective energy use and the ability to decide… More >

  • Open Access


    Duffing Oscillator’s Vibration Control under Resonance with a Negative Velocity Feedback Control and Time Delay

    Y. A. Amer1, Taher A. Bahnasy2,*

    Sound & Vibration, Vol.55, No.3, pp. 191-201, 2021, DOI:10.32604/sv.2021.014358

    Abstract An externally excited Duffing oscillator under feedback control is discussed and analyzed under the worst resonance case. Multiple time scales method is applied for this system to find analytic solution with the existence and nonexistence of the time delay on control loop. An appropriate stability analysis is also performed and appropriate choices for the feedback gains and the time delay are found in order to reduce the amplitude peak. Different response curves are involved to show and compare controller effects. In addition, analytic solutions are compared with numerical approximation solutions using Rung-Kutta method of fourth order. More >

  • Open Access


    Position and Velocity Time Delay for Suppression Vibrations of a Hybrid Rayleigh-Van der Pol-Duffing Oscillator

    Y. A. Amer1, A. T. El-Sayed2, M. N. Abd El-Salam3,*

    Sound & Vibration, Vol.54, No.3, pp. 149-161, 2020, DOI:10.32604/sv.2020.08469

    Abstract In this paper, we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing oscillator. This system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an external force. We applied the multiple scales method to get the solution from first approximation. Graphically and numerically, we studied the system before and after adding time delay feedback at the primary resonance case (Ω ≌ ω). We used MATLAB program to simulate the efficacy of different parameters and the time delay on the main system. More >

  • Open Access


    An Application of Support Vector Regression for Impact Load Estimation Using Fiber Bragg Grating Sensors

    Clyde K Coelho, Cristobal Hiche, Aditi Chattopadhyay

    Structural Durability & Health Monitoring, Vol.7, No.1&2, pp. 65-82, 2011, DOI:10.3970/sdhm.2011.007.065

    Abstract Low velocity impacts on composite plates often create subsurface damage that is difficult to diagnose. Fiber Bragg grating (FBG) sensors can be used to detect subsurface damage in composite laminates due to low velocity impact. This paper focuses on the prediction of impact loading in composite structures as a function of time using a support vector regression approach. A time delay embedding feature extraction scheme is used since it can characterize the dynamics of the impact using the sensor signals. The novelty of this approach is that it can be applied on complex geometries and does not require a dense… More >

  • Open Access


    A Semi-Discretizing Method Based Efficient Model for Fluidelastic Instability Threshold Prediction of Tube Bundles

    Yuerong Wang1, Jianping Jing1,2,3,*, Changmin Chen1, Sheng Xiong1

    CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.1, pp. 1-22, 2019, DOI:10.32604/cmes.2019.06158

    Abstract Fluidelastic instability is destructive in tube bundles subjected to cross flow. Flow channel model proposed by Leaver and Weaver is well used for modeling this problem. However, as the tube motion is supposed to be harmonic, it may not simulate the general dynamic behaviors of tubes. To improve this, a model with arbitrary tube motion is proposed by Hassan and Hayder. While, due to involving in the time delay term, the stability problem cannot be solved by the eigenvalue scheme, and time domain responses of the tube have to be obtained to assess the instability threshold. To overcome this weakness,… More >

  • Open Access


    Audible Threshold of Early Reflections with Different Orientations and Delays

    Xiaoli Zhong1, 2, Wenying Guo1, Jie Wang2

    Sound & Vibration, Vol.52, No.6, pp. 18-22, 2018, DOI:10.32604/sv.2018.03900

    Abstract Early reflection is an important component in an enclosed sound field. Due to the precedence effect, the early reflection may not be the dominant factor in sound source localization; however, it still has obvious influences on spatial position, loudness, timbre, and etc. Till now, there have sparse studies on evaluation of the audible threshold of early reflections with lacking of general and quantitative results. This work investigated the audible threshold of early reflection with a simplified sound field model under various experimental conditions including the combination of eight incidence angles and five time delays. Three-down-one-up adaptive strategy with three-interval three-alternative… More >

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