A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are suucient to construct a general quantum circuit. The best previous result had shown the universality of three-bit gates, by analogy to the universality of the Tof-foli three-bit gate of classical reversible computing. Two-bit quantum gates may be implem...

Localized defects in rotating mechanical parts tend to result in impulse response in vibration signal, which contain important information about system dynamics being analyzed. Thus, parameter identification of impulse response provides a potential approach for localized fault diagnosis. A method combining the Morlet wavelet and correlation filtering, named Cyclic Morlet Wavelet Correlation Fil...

The gearbox is one of the key components in wind turbines. Gearbox fault signals are usually nonstationary and highly contaminated with noise. The presence of amplitude-modulated and frequency-modulated (AM-FM) characteristics compound the difficulty of precise fault diagnosis of wind turbines, therefore, it is crucial to develop an effective fault diagnosis method for such equipment. This pape...

Ensemble empirical mode decomposition (EEMD) is a noiseassisted method and also a significant improvement on empirical mode decomposition (EMD). However, the EEMD method lacks a guide to choosing the appropriate amplitude of added noise and its computation efficiency is fairly low. To alleviate the problems of the EEMD method, the improved complementary EEMD method (ICEEMD) was proposed. Furthe...

Due to industrial importance of gears in power transmission systems, fault detection and diagnosis of gear transmission systems have attracted considerable attention in recent years, there is constant pressure to improve measuring techniques and tools for early detection and diagnosis of gearbox faults. The time and frequency localization properties of continuous wavelet transform offers a viab...

The development of enhanced fault detection ability for gearbox systems has received considerable attention in recent years. Detecting the gear fault easier is very important for maintenance action. This has driven the need in research for enhanced gear fault detection method. The goal is to extract periodic impulse signal from the very noise signal which mainly contains the narrowband signals....

This paper deals with signal processing techniques for non-destructive fault detection on gearbox of helicopter by using time synchronous averaging. Time synchronous averaging is a signal processing technique that is used to extract repetitive signals from additive noise. This process requires an accurate measurement of the repetitive frequency of the desired signal or a signal that is synchron...

Lubrication oil plays a decisive role to maintain a reliable and efficient operation of gear transmissions. Many offline methods have been developed to monitor the quality of lubricating oils. This work focus on developing a novel online method to diagnose oil degradation based on the measurements from power supply system to the gearbox. Experimental studies based on an 10kW industrial gearbox ...

This paper presents an efficient design tool for the estimation of the transient electromagnetic peak torque and transient rotor over-voltages of wind turbines (WT) doubly-fed induction generators (DFIG) during severe fault conditions on the grid side. This versatile and robust tool is well adapted to the implementation in a DFIG drives CAD environment using iterative optimization procedures. I...