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  • 1
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    Adaptive Second Order Sliding Mode Control of a Fuel Cell Hybrid System for Electric Vehicle Applications (2015)
    Hindawi
    Details
    Publication Date: 2015-07-30
    Description: We present an adaptive-gain second order sliding mode (SOSM) control applied to a hybrid power system for electric vehicle applications. The main advantage of the adaptive SOSM is that it does not require the upper bound of the uncertainty. The proposed hybrid system consists of a polymer electrolyte membrane fuel cell (PEMFC) with a unidirectional DC/DC converter and a Li-ion battery stack with a bidirectional DC/DC converter, where the PEMFC is employed as the primary energy source and the battery is employed as the second energy source. One of the main limitations of the FC is its slow dynamics mainly due to the air-feed system and fuel-delivery system. Fuel starvation phenomenon will occur during fast load demand. Therefore, the second energy source is required to assist the main source to improve system perofrmance. The proposed energy management system contains two cascade control structures, which are used to regulate the fuel cell and battery currents to track the given reference currents and stabilize the DC bus voltage while satisfying the physical limitations. The proposed control strategy is evaluated for two real driving cycles, that is, Urban Dynamometer Driving Schedule (UDDS) and Highway Fuel Economy Driving Schedule (HWFET).
    Print ISSN: 1024-123X
    Electronic ISSN: 1563-5147
    Topics: Mathematics , Technology
    Published by Hindawi
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  • 2
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    Coverage Restoration Method for Wireless Sensor Networks of Distributed PV System (2015)
    Hindawi
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    Publication Date: 2015-02-24
    Description: Continuous capacity increase of distributed grid-connected photovoltaic (PV) system produces more obvious disturbance on the grid. Monitoring network technology can provide protection for the safety and stability of power grid operation, but sensor nodes of the monitoring network will fall to failure due to environmental interference. According to the performance degradation problem caused by nodes failure in PV monitoring network, particle swarm optimization (PSO) of natural selection based on random weight is proposed in this paper to optimize monitoring performance. This method can restore the monitoring network by arousing redundant nodes. Simulation results show the effectiveness of the proposed algorithm.
    Print ISSN: 1550-1329
    Electronic ISSN: 1550-1477
    Topics: Electrical Engineering, Measurement and Control Technology
    Published by Hindawi
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  • 3
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    Acoustic Source Localization via Subspace Based Method Using Small Aperture MEMS Arrays (2014)
    Hindawi
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    Publication Date: 2014-07-17
    Description: Small aperture microphone arrays provide many advantages for portable devices and hearing aid equipment. In this paper, a subspace based localization method is proposed for acoustic source using small aperture arrays. The effects of array aperture on localization are analyzed by using array response (array manifold). Besides array aperture, the frequency of acoustic source and the variance of signal power are simulated to demonstrate how to optimize localization performance, which is carried out by introducing frequency error with the proposed method. The proposed method for 5 mm array aperture is validated by simulations and experiments with MEMS microphone arrays. Different types of acoustic sources can be localized with the highest precision of 6 degrees even in the presence of wind noise and other noises. Furthermore, the proposed method reduces the computational complexity compared with other methods.
    Print ISSN: 1687-725X
    Electronic ISSN: 1687-7268
    Topics: Electrical Engineering, Measurement and Control Technology
    Published by Hindawi
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  • 4
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    Yagi Array of Microstrip Quarter-Wave Patch Antennas with Microstrip Lines Coupling (2014)
    Hindawi
    Details
    Publication Date: 2014-07-23
    Description: A new kind of Yagi array of quarter-wave patch antennas is presented. The Yagi array has a low profile, a wide bandwidth, and a high gain. A main beam close to endfire is produced, with a vertical polarization in the horizontal plane. A set of microstrip lines are introduced between the driven element and the first director element to enhance the coupling between them, and therefore the bandwidth could be increased and the back lobes could be suppressed. Measured results show that the Yagi array with 4 elements generates a peak gain of about 9.7 dBi, a front-to-back ratio higher than 10 dB, and a 10 dB return loss band from 4.68 GHz to 5.24 GHz, with a profile of 1.5 mm and an overall size of 80 × 100 mm2. An increase of the number of director elements would enhance the gain and have the main beam pointing closer to endfire.
    Print ISSN: 1687-5869
    Electronic ISSN: 1687-5877
    Topics: Electrical Engineering, Measurement and Control Technology
    Published by Hindawi
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  • 5
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    Multiple Data-Dependent Kernel Fisher Discriminant Analysis for Face Recognition (2014)
    Hindawi
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    Publication Date: 2014-01-01
    Description: Kernel Fisher discriminant analysis (KFDA) method has demonstrated its success in extracting facial features for face recognition. Compared to linear techniques, it can better describe the complex and nonlinear variations of face images. However, a single kernel is not always suitable for the applications of face recognition which contain data from multiple, heterogeneous sources, such as face images under huge variations of pose, illumination, and facial expression. To improve the performance of KFDA in face recognition, a novel algorithm named multiple data-dependent kernel Fisher discriminant analysis (MDKFDA) is proposed in this paper. The constructed multiple data-dependent kernel (MDK) is a combination of several base kernels with a data-dependent kernel constraint on their weights. By solving the optimization equation based on Fisher criterion and maximizing the margin criterion, the parameter optimization of data-dependent kernel and multiple base kernels is achieved. Experimental results on the three face databases validate the effectiveness of the proposed algorithm.
    Print ISSN: 1024-123X
    Electronic ISSN: 1563-5147
    Topics: Mathematics , Technology
    Published by Hindawi
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  • 6
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    A Novel SHMPWM Technique for Sensorless Control in High-Power PMSM (2015)
    Hindawi
    Details
    Publication Date: 2015-01-01
    Description: In view of the low switching frequency restriction of high-power permanent magnet synchronous motor (PMSM) drive system and longing for sensorless control in hostile conditions, a novel PWM control scheme, born out of selective harmonic mitigation pulse width modulation (SHMPWM) technique, was proposed for sensorless control of high-power PMSM. A new enhanced constraint was placed on the traditional SHMPWM nonlinear transcendental equation to selectively generate constant amount of a certain3k+1order harmonic signals while guaranteed that the undesired harmonic signals can be suppressed. At the same time, the3k+1order harmonic signals were extracted by band-pass filter, which had the constant amplitude and phase angle difference of 120°, equivalent to inject rotating voltage vector in the natural coordinate system of motor, and the rotor position can be estimated using the3k+1order harmonic signals. The nonlinear transcendental equation of the novel modulation technique had been designed, and its numerical method had been analyzed. The rotor position observer had been designed according to the3k+1order harmonic signals. Simulation results verify that the harmonic suppression of the system was implemented, and the sensorless control was efficient by the novel SHMPWM technique.
    Print ISSN: 1024-123X
    Electronic ISSN: 1563-5147
    Topics: Mathematics , Technology
    Published by Hindawi
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  • 7
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    Study on Adaptive Slid Mode Controller for Improving Handling Stability of Motorized Electric Vehicles (2014)
    Hindawi
    Details
    Publication Date: 2014-01-01
    Description: An adaptive slid mode controller was established for improving the handling stability of motorized electric vehicle (MEV). First and foremost, the structure and advantages of electric vehicle driven by in-wheel motors will be provided. Then, an ideal cornering model of vehicles will be brought and analyzed, after which a method to estimate side-slip angle was also proposed and three typical sensors were used in the theory. Besides, an idea for the recognition of road adhesion coefficient was derived based on MEV platform, which will be helpful for better control performances. Finally, the scheme of control method was given and some typical tests for observing handling properties were implemented based on Simulink and Carsim software. With the outcomes from the experiments, which vividly showed the merits of the controller, one can come to a conclusion that MEV that equips with the adaptive slid mode controller always enjoys better handling performances than the one without control. Furthermore, the controller researched is friendly to the real-time working conditions, which will hold practical values in the future.
    Print ISSN: 1024-123X
    Electronic ISSN: 1563-5147
    Topics: Mathematics , Technology
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  • 8
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    Rapid and Selective Determination of Folate Receptor α with Sensitive Resonance Rayleigh Scattering Signal (2017)
    Hindawi
    Details
    Publication Date: 2017-05-25
    Description: A rapid, simple, and novel method for folate receptor α (FRα) determination is reported here. A probe of gold nanoparticles (Au NPs) modified with anti-FRα antibody was synthesized under the optimized conditions first. The antibody-modified Au NPs would aggregate when FRα was added to the probe for the specific interaction between antibody and antigen, resulting in the enhancement of resonance Rayleigh scattering (RRS) intensity. There is a linear relationship between the change of RRS intensity (ΔIRRS) and the concentration of FRα, with the detecting range of 0.50–37.50 ng·mL−1 and the limit of determination of 0.05 ng·mL−1. The determination of FRα in serum samples was realized with the advantages of high selectivity, high sensitivity, and easy operation.
    Print ISSN: 1687-8760
    Electronic ISSN: 1687-8779
    Topics: Chemistry and Pharmacology
    Published by Hindawi
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  • 9
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    Motion Reliability Analysis of the Delta Parallel Robot considering Mechanism Errors (2019)
    Hindawi
    Details
    Publication Date: 2019-05-02
    Description: Delta parallel robots are widely used in assembly detection, packaging sorting, precision positioning, and other fields. With the widespread use of robots, people have increasing requirements for motion accuracy and reliability. This paper considers the influence of various mechanism errors on the motion accuracy and analyzes the motion reliability of the mechanism. Firstly, we establish a kinematic model of the robot and obtain the relationship between the position of the end effector and the structural parameters based on the improved D–H transform rule. Secondly, an error model considering the dimension error, the error of revolute joint clearance, driving error, and the error of spherical joint clearance is established. Finally, taking an actual robot as an example, the comprehensive influence of mechanism errors on motion accuracy and reliability in different directions is quantitatively analyzed. It is shown that the driving error is a key factor determining the motion accuracy and reliability. The influence of mechanism errors on motion reliability is different in different directions. The influence of mechanism errors on reliability is small in the vertical direction, while it is great in the horizontal direction. Therefore, we should strictly control the mechanism errors, especially the driving angle, to ensure the motion accuracy and reliability. This research has significance for error compensation, motion reliability analysis, and reliability prediction in robots, and the conclusions can be extended to similar mechanisms.
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    Topics: Mathematics , Technology
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  • 10
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    ISAR Autofocus Imaging Algorithm for Maneuvering Targets Based on Phase Retrieval and Keystone Transform (2019)
    Hindawi
    Details
    Publication Date: 2019-03-26
    Description: In the current scenario of high-range resolution radar and noncooperative target, the rotational motion parameters of the target are unknown and migration through resolution cells (MTRC) is apparent in the obtained inverse synthetic aperture radar (ISAR)images, in both slant-range and cross-range directions. In the case of the high-speed maneuvering target with a small value of rotation, the phase retrieval algorithm can be applied to compensate for the translational motion to form an autofocusing image. However, when the target has a relatively large rotation angle during the coherent integration time, phase retrieval method cannot get an acceptable image for viewing and analysis as the location of the scatterer will not be true due to the Doppler shift imposed by the target’s rotational motion. In this paper, a novel ISAR imaging method for maneuvering targets based on phase retrieval and keystone transform is proposed, which can effectively solve the above problems. First, the keystone transform is used to solve the MTRC effects caused by the rotation component. Next, phase errors caused by the remaining translational motion will be removed by employing phase retrieval algorithm, allowing the scatterers are always kept in their range cells. Finally, the Doppler frequency shifts of scatterers will be time invariant in the phase of the received signal. Furthermore, this approach does not need to estimate the motion parameters of the target, which simplifies the processing steps. The simulated results demonstrate the validity of this method.
    Print ISSN: 1687-5869
    Electronic ISSN: 1687-5877
    Topics: Electrical Engineering, Measurement and Control Technology
    Published by Hindawi
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