Modeling of electric vehicle chargers

The chargers of electric vehicles (EV) are highly non-linear devices. They are characterized by high harmonic current distortion and poor power factor. Different models of chargers and converters had been studied and a number of papers were published. In order to study the impacts of a large number of electric vehicles to the power system, an appropriate charger model for a population of EVs should be developed. To illustrate the process in using Monte Carlo method to describe the interaction of EV chargers, the mean value of the total harmonic distortion (THD) is estimated as it is one of the most important parameters should be studied. Different charging algorithms will have different performance and harmonic distortion. Since current-voltage control charging method is widely adopted for various types of batteries, a model based on this algorithm is presented.published_or_final_versio

A practical postprocessing technique for real-time block-based coding system

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Neuro-Fuzzy Speed Tracking Control of Traveling-Wave Ultrasonic Motor Drives Using Direct Pulsewidth Modulation

The traveling-wave ultrasonic motor (TWUM) drive offers many distinct advantages but suffers from severe system nonlinearities and parameter variations, especially during speed control. This paper presents a new speed tracking control system for the TWUM drive, which newly incorporates neuro-fuzzy control and direct pulsewidth modulation to solve the problem of nonlinearities and variations. The proposed control system is digitally implemented by a low-cost digital-signal-processor-based microcontroller, hence reducing the system hardware size and cost. Experimental results confirm that the proposed speed tracking controller can offer good steady-state and transient performance.published_or_final_versio

A practical real-time post-processing technique for block effect elimination

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Subband adaptive regularization method for removing blocking effect

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Neuro-fuzzy dual-mode control of travelling-wave ultrasonic motors

With their significant advantages over traditional electromagnetic motors, ultrasonic motors (USMs) are becoming attractive. This paper presents a neuro-fuzzy dual-mode controller, combining the knowledge-based fuzzy logic and the learning-incorporated neural network as well as using dual control inputs, for servo control of travelling-wave USMs. According to the proposed neuro-fuzzy control, both the driving frequency and phase difference of the USM system are simultaneously adjusted on-line. Experimental results have verified its superior steady-state and dynamic performances under various reference inputspublished_or_final_versio

Perioperative use of statins in noncardiac surgery

Background: Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) can significantly decrease cardiovascular mortality and morbidity, irrespective of the patients' cholesterol status. This paper reviews the effects of perioperative statin therapy in patients undergoing noncardiac surgery. Method: A systematic literature review was undertaken of all published literature on this subject using Medline and cross-referenced. All published relevant papers on the perioperative use of statins were used. Results: Perioperative statin therapy is associated with a lower perioperative morbidity and mortality in patients undergoing elective or emergency surgery. The effects are due to a combination of lipid-lowering and pleiotropic properties of statins. Conclusion: Ideally a large scale multi-centre randomized controlled trial of perioperative statin therapy should be performed but this may be difficult to conduct since there is already overwhelming evidence in the literature to suggest perioperative cardiovascular protective properties. Statins may still be under-prescribed in surgical patients. © 2008 Chan et al, publisher and licensee Dove Medical Press Ltd.published_or_final_versio

Second-order Direct Analysis of Steel Structures made of tapered members

[EN] Mild steel hot-rolled sections are commonly prismatic because of the rolling process with a furnace, but welded sections made from steel plates do not have such a constraint, especially when robotic welding machines are used. The weight saving could be very significant by, say, using wide flanged section at mid-span and a small flanged section at ends of a simply supported beam. However, design codes do not provide formulae for buckling check of tapered members. This paper proposes a code-free second-order direct analysis for stabilty design of steel frames made of tapered members. The design is further applied to a single layered mega space frame of 136m span. In the whole design process based on the concept of Second-order Direct Analysis, no uncertain effective length and independent member buckling checking are required.The authors are grateful to the financial supports by the Research Grant Council of the Hong Kong SAR Government on the project “Second-Order Analysis of Shallow Dome Structures Made of Tapering Members (PolyU 152047/17E)” and Second-Order Analysis of Flexible Steel Cable Nets Supporting Debris (PolyU 152008/15E)” and support by Innovation and Technology Fund of the Hong Kong SAR Government for the project “Development of an energy absorbing device for flexible rock-fall barriers (ITS/059/16FP)” and by the Hong Kong Branch of Chinese National Engineering Research Centre for Steel Construction of The Innovation and Technology Fund of the Hong Kong SAR Government for the project Advanced Numerical Analysis for Building Structures using High Performance Steel Materials".Chan, S.; Liu, S.; Liu, Y. (2018). Second-order Direct Analysis of Steel Structures made of tapered members. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 75-82. https://doi.org/10.4995/ASCCS2018.2018.7221OCS758

Regularized restoration of VQ compressed images with constrained least squares approach

Author name used in this publication: S. W. HongVersion of RecordPublishe

Panax ginsengRhodiola rosea and schisandra chinensis

2011-2012 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe