Taiwan Association of Engineering and Technology Innovation: E-Journals
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Enhanced Kalman Filter Navigation Algorithm Based on Correntropy and Fixed-Point Update
Get PDFThe accuracy of position estimation plays a key role in many of the precise positioning applications such as category I (CAT-I) aircraft landings, survey work, etc. To improve the accuracy of position estimation, a novel kinematic positioning algorithm designated as correntropy Kalman filter (CKF) is proposed in this study. Instead of minimum mean square error (MMSE), correntropy criterion (CC) is used as the optimality criterion of CKF. The prior estimates of the state and covariance matrix are computed in CKF and a novel fixed-point algorithm is then used to update the posterior estimates. The data of a dual-frequency global positioning system (GPS) receiver located at Indian Institute of Science (IISc), Bangalore (13.021°N/77.5°E) is collected from Scripps Orbit and Permanent Array Centre (SOPAC) to implement the proposed algorithm. The results of the proposed CKF algorithm are promising and exhibit significant improvement in position estimation compared to the conventional methods
Mechanical and Durability Properties of High-Performance Concrete Incorporating Fibers and Algerian Natural Pozzolans in Chloride Attack
Get PDFThis study aims to assess the effect of sodium chloride attack on the mechanical and durability properties of high-performance concrete (HPC) based on fibers and natural pozzolans. The resistance of specimens against chemical attack is determined by the unit weight, compressive strength, splitting-tensile strength, chloride ion permeability, apparent gas permeability, and visual inspection after 28, 90, 180, and 365 days of testing. A total of three types of concrete are assessed: reference concrete (RC), HPC, and high-performance fiber-reinforced concrete (HPFRC) stored in tap water and aggressive water (i.e., a 10% NaCl solution). The test results demonstrate that the presence of fibers negatively affects the permeability of HPC. However, HPC and HPFRC remain stable and are not influenced by the NaCl solution compared to RC. The natural pozzolans attenuate the side effect of fibers by occupying voids (i.e., the filler effect) and generating denser products (i.e., the pozzolanic reaction) in the cement matrix
Modified Digital Correlation Technique for Accurate Phase Measurement in Multi-Frequency Bio-Impedance Analysis
Get PDFIn bio-impedance analysis (BIA), high-frequency low-amplitude alternating current (AC) signals can incur time delays due to the capacitive nature of human cell membranes, and the characteristics of human tissues can be assessed from these delays in terms of phase changes. To accurately measure the phase changes, this work proposes a modified digital correlation-based phase measurement method. The accuracy of the general correlation technique is improved through digital direct synthesis (DDS) and digital correlation of unipolar square input signals. The proposed method is established through memory management and frequency adjustment. The result shows that, compared to the existing methods, the proposed method needs fewer hardware components, has better accuracy of 0.2° and higher frequency compatibility from 5 kHz to 1 MHz, and requires lower cost (140 USD). The method can be applied for the BIA of all types of tissues (recently used in COVID detection and care) and for the applications where efficient phase measurement is required
Development of Non-Contact Real-Time Monitoring System for Animal Body Temperature
Get PDFBody temperature is an important indicator of health monitoring. However, since animals are covered with fur, it is difficult to obtain their accurate body temperature with the traditional infrared measurement technology. To deal with this problem, this research proposes a non-contact real-time monitoring system using an infrared method combined with object detection. The system is developed based on general infrared thermal imaging technology and an infrared thermal imaging module with an image tracking algorithm. YOLO is used to detect animals, and a thermal imaging camera is used to measure the body surface temperature of animals. The result shows that the proposed system can accurately measure the body temperature of animals without being influenced by animals’ fur. In the future, it can be applied to monitor the body temperature of sick animals in veterinary hospitals
Application of AI Face Recognition Technology in Swipe Card Attendance Systems for Hospitals
Get PDFTraditional swipe card attendance systems for hospitals cannot effectively protect employees’ personal information and ensure that the employees are swiping their own cards. To solve the problem, the present study proposes a novel hospital swipe card attendance system using an artificial intelligence (AI) face modeling system with an open-source face database. The proposed system employs a multi-task cascaded convolutional network (MTCNN) algorithm and FaceNet to improve the performance of face recognition. The system can compare the face of the one who swipes a card with the faces of cardholders in the database, thereby preventing the one from clocking in on behalf of others. The results show that the application of AI technology in the hospital swipe card attendance system can realize the promise of protecting employees’ personal information and verifying employees’ identities
Circularly Polarized Antennas Using Characteristic Mode Analysis: A Review
Get PDFCharacteristic mode analysis (CMA) can be used in antenna designs to solve radiation problems. This review focuses on the existing development methodologies for circularly polarized (CP) antennas and their axial ratio bandwidth (ARBW) improvement using CMA. To discuss the physical insights related to CP radiation, this study systematically examines different antenna design structures used in previous research. It investigates the impact of modal parameters such as the eigenvalue, modal significance (MS), characteristic angle (CA), surface current, far-field radiation behavior on CP radiation, and ARBW for various antenna designs. In addition, it discusses the comparative analysis of various antenna design approaches in terms of antenna performance parameters such as the operating frequency band, ARBW, and gain. The results show that CMA provides more valuable information for the selection of feed position in antenna designs than the conventional full-wave simulation approach
Finite Element and Neural Network Based Predictive Model to Determine Natural Frequency of Laminated Composite Plates with Eccentric Cutouts under Free Vibration
Get PDFThis research proposes a predictive model to identify changes in the mechanical and geometrical properties of composite plates with eccentric cutouts based on natural frequency. Finite elements (FE) and neural networks are used to develop the model based on machine learning. First, the numerical analysis of free vibration is performed by the FE model on the laminated composite plates with a stacking sequence [0/90]2s under a clamped-free (CFFF) boundary condition. The outputs of the FE model (520 configurations) are then utilized to train the artificial neural network (ANN) model through the Levenberg-Marquardt method, and the developed ANN model is then used to evaluate the influence of various parameters on the natural frequency. The results show that the changes in the mechanical and geometrical properties of composite plates have impacts on the natural frequency. Furthermore, the findings of the ANN model are substantially identical to those of the numerical model, with a small margin of error
Observer-Based Quadratic Guaranteed Cost Control for Linear Uncertain Systems with Control Gain Variation
Get PDFThis study proposes a method for designing observer-based quadratic guaranteed cost controllers for linear uncertain systems with control gain variations. In the proposed approach, an observer is designed, and then a feedback controller that ensures the upper bound on the given quadratic cost function is derived. This study shows that sufficient conditions for the existence of the observer-based quadratic guaranteed cost controller are given in terms of linear matrix inequalities. A sub-optimal quadratic guaranteed cost control strategy is also discussed. Finally, the effectiveness of the proposed controller is illustrated by a numerical example. The result shows that the proposed controller is more effective than conventional methods even if system uncertainties and control gain variations exist
Measurement Accuracy of Ultrasound Viscoelastic Creep Imaging in Measuring the Viscoelastic Properties of Heterogeneous Materials
Get PDFUltrasound viscoelastic creep imaging (UVCI) is a newly developed technology aiming to measure the viscoelastic properties of materials. The purpose of this study is to investigate the accuracy of UVCI in measuring the viscoelastic properties of heterogeneous materials that mimic pathological lesions and normal tissues. The finite element simulation is used to investigate the measurement accuracy of UVCI on three material models, including a homogeneous material, a single-inclusion phantom, and a three-layer structure. The measurement accuracy for a viscoelastic property is determined by the difference between the simulated measurement result of that viscoelastic property and its true value defined during the simulation process. The results show that UVCI in general cannot accurately measure the true values of the viscoelastic properties of a heterogeneous material, demonstrating the need to further improve the theories and technologies relevant to UVCI to improve its measurement accuracy on tissue-like heterogeneous materials
Electronically Controlled Biquadratic Filter and Quadrature Oscillator Using CDTAs
Get PDFThis article presents a current-mode biquadratic filter and quadrature oscillator circuit based on current differencing transconductance amplifiers (CDTAs). The proposed circuit does not require changing the circuit topology. In addition to the low-pass filter, high-pass filter, band-pass filter, and sinusoidal quadrature signal, the proposed circuit has a pole frequency that can be controlled independently from the quality factor, while the oscillation frequency can be controlled non-interactively. The circuit impedance with high output can directly drive the load without using a current buffer. Furthermore, grounded capacitors can function without the use of external resistors. This qualification is ideal for the future development of integrated circuits (ICs). After the PSPICE simulation with 90 nm CMOS parameters and the experiments by commercial ICs, the results are consistent with the theoretical analysis of the proposed circuit