Human gait recognition using localized Grassmann mean representatives with partial least squares regression

Multimedia Tools and Applications - Gait recognition has become popular due to the rising demand for nonintrusive biometrics. At its nascent stage of development, gait recognition faces a number of...     

Discussion of papers

This paper describes a bridge condition assessment model that is based upon the simplification of a computational technique called resolution identity of fuzzy sets. The proposed model utilizes a fuzzy weighted average to combine fuzzy bridge condition ratings. The procedure is based on the decomposition of fuzzy sets into non-fuzzy level-sets or intervals. The utility and effectiveness of this procedure are illustrated with an example of the bridge condition assessment problem.     

Comprehensive Warpage Analysis of Stacked Die MEMS Package in Accelerometer Application

<正>Packaging of MEMS ( micro-electro-mechanical system ) devices poses more challenges than conventional IC packaging, since the performance of the MEMS devices is highly dependent on packaging processes. A Land Grid Array ( LGA ) package is introduced for MEMS technology based linear multi-axis accelerometers. Finite element modeling is conducted to simulate the warpage behavior of the LGA packages. A method to correlate the package warpage to matrix block warpage has been developed. Warpage for both package and sensor substrate are obtained. Warpage predicted by simulation correlates very well with experimental measurements. Based on this validated method, detailed design analysis with different package geometrical variations are carried out to optimize the package design. With the optimized package structure, the packaging effect on accelerometer signal performance is well controlled.     

An efficient solution for mitigating light-load penalty in EPONs

In this paper, an effective medium access control protocol is proposed for Ethernet passive optical networks. By combining the bandwidth guarantee polling (BGP) scheme with the strict priority queuing (SPQ) mechanism, the proposed solution can greatly mitigate the light-load penalty while supporting differentiated services. The performance of the proposed solution has been demonstrated by the simulation results.     

Numerical Optimization of an Active Voltage Controller for High-Power IGBT Converters

Feedback control of insulated gate bipolar transistors (IGBTs) in the active region can be used to regulate the device switching trajectory. This facilitates series connection of devices without the use of external snubber networks. Control must be achieved across the full active region of the IGBT and must balance a number of conflicting system goals including diode recovery. To date, the choice of control parameters has been a largely empirical process. This paper uses accurate device models and formalized optimization procedures to evaluate IGBT active voltage controllers. A detailed optimization for the control of IGBT turn-on is presented in this paper     

Towards a new model of crack tip stress fields

This work introduces a novel mathematical model of the stresses around the tip of a fatigue crack, which considers the effects of plasticity through an analysis of their shielding effects on the applied elastic field. The ability of the model to characterize plasticity-induced effects of cyclic loading on the elastic stress fields is assessed and demonstrated using full-field photoelasticity. The focus is on determining the form of the shielding stress components (induced by compatibility requirements at the elastic–plastic interface along the crack flank and via the crack tip plastic zone) and how they influence the crack tip elastic stress fields during a load cycle. The model is successfully applied to the analysis of a fatigue crack growing in a polycarbonate CT specimen.     

Transient response of ARROW VCSELs

The transient response of antiresonant reflecting optical waveguide (ARROW) vertical-cavity surface-emitting lasers (VCSELs) is analyzed. It is found that under current modulation, the radiation loss of the transverse-leaky mode decreases during the state of the lasers but increases during the state. Numerical analysis shows that this variation in radiation loss is due to the carrier-induced refractive-index depression that arises from spatial-hole-burning of carrier concentration. It is noted that the increment in radiation loss during the state can be used to prevent net modal gain of the transverse-leaky mode from reacquiring threshold after turn-off. Hence, a new method to design ARROW, based on the variation in radiation loss, is proposed to eliminate the excitation of secondary pulsation in VCSELs. The influence of thermal lensing effects on the excitation of secondary pulsation during the state of the lasers is also investigated.     

Joint trellis-coded quantisation/modulation

Joint trellis-coded quantisation (TCQ) and trellis-coded modulation (TCM) can achieve considerable signal-to-quantisation noise ratios with moderate complexity. TCM is replaced with turbo TCM (TTCM) and simulation results given which show that the new scheme can achieve the same performance as that possible using by trellis-coded scalar quantisation at an SNR slightly above the channel capacity bound     

Performance analysis under dynamic loading of wavelength continuous and non‐continuous WDM networks with shortest‐path routing

The performance of WDM networks using shortest path routing is studied under wavelength continuous (WC) and non‐continuous (NWC) constraints and dynamic traffic loading. Approximate analytical models are presented for the performance studies of such systems. Results of numerical calculations based on these models and simulations are given for different network topologies for the purposes of comparison. These analytical and simulation results are used to study the performance of these WDM networks under dynamic traffic loading. Copyright © 2001 John Wiley & Sons, Ltd.