Digital Commons Network^™

Self-Similar Solutions Of Fully Nonlinear Curvature Flows, James Alexander Mccoy

Faculty of Informatics - Papers (Archive)

We consider closed hypersurfaces which shrink self-similarly under a natural class of fully nonlinear curvature flows. For those flows in our class with speeds homogeneous of degree 1 and either convex or concave, we show that the only such hypersurfaces are shrinking spheres. In the setting of convex hypersurfaces, we show under a weaker second derivative condition on the speed that again only shrinking spheres are possible. For surfaces this result is extended in some cases by a different method to speeds of homogeneity greater than 1. Finally we show that self-similar hypersurfaces with sufficiently pinched principal curvatures, depending on …

Self-Matching Bands In The Paperfolding Sequence, Bruce Bates, Martin Bunder, Keith Tognetti

Faculty of Informatics - Papers (Archive)

We compare term by term the paperfolding sequence with a copy displaced by d terms to obtain the matching fraction M(d).

Using Singularity Theory To Analyse A Spatially Uniform Model Of Self-Heating In Compost Piles, Thiansiri Luangwilai, Harvinder Sidhu, Mark Nelson, Xiao Dong Chen

Faculty of Informatics - Papers (Archive)

Fires at industrial composting facilities, such as those storing industrial waste products like municipal solid waste (NSW) and landfills are fairly common. In most cases these are manageable and such incidents are not destructive enough to attract attention beyond these facilities. However, over the years there have been a few notable devastating fires at such facilities.

In each of these industrial processes there is an inherent increase in temperature as a consequence of the biological activity. Indeed such a temperature increase is one of the goals of the composting waste. Elevated temperatures of the order of 70-90 degrees celsius have …

An Estimation Method For Feedback Level Factor C Of A Self-Mixing Interferometry System, Yuanlong Fan, Yanguang Yu, Jiangtao Xi, Joe F. Chicharo

Faculty of Informatics - Papers (Archive)

This paper presents a fast estimation method for feedback level factor C of a self-mixing interferometry (SMI) system. The reconstruction of a displacement waveform using a SMI signal needs to know a C value. However, it is difficult to maintain a constant C value during the reconstruction process. We study the features of the reconstructed displacement waveforms incorporating different pre-set C values and classify waveforms into two types. Bisection method is introduced in our method for fast estimating C value. The effectiveness of our proposed method has been verified by both simulation and experimental data.

The Semenov Formulation Of The Biological Self-Heating Process In Compost Piles, Thiansiri Luangwilai, Harvinder Sidhu, M I. Nelson, X D. Chen

Faculty of Informatics - Papers (Archive)

We formulate and investigate a uniformly distributed mathematical model (based upon Semenov's theory for thermal explosions) for the thermal response of cellulosic materials in compost piles. The model consists of a mass balance equation for oxygen, a heat balance equation, and incorporates the heat release due to biological activity within the pile. Biological heat generation is known to be present in most industrial processes handling large volumes of bulk organic materials. We utilise singularity theory to investigate the generic properties of the model, as well as to determine the locus of different singularities, namely the cusp, isola and double limit …

Fpga-Based Signal Processing In An Optical Feedback Self-Mixing Interferometry System, Zongzhen Li, Yanguang Yu, Jiangtao Xi, Huiying Ye

Faculty of Informatics - Papers (Archive)

Optical feedback Self-mixing Interferometry (OFSMI) can achieve a high-resolution displacement sensing and measurement by using advanced digital signal processing. However, most existing signal processing algorithms used for OFSMI signals are implemented on a PC by Matlab or other programming languages. In this case, the whole structure of OFSMI sensing system is incompact and the measurement is in low speed. The design trends in sensing systems are towarding to small size, high integration and fast real time processing. These trends require us to improve the existing OFSMI design. It is a good solution to apply Field-programmable gate arrays (FPGAs) technique onto …

The Fourier Spectrum Analysis Of Optical Feedback Self-Mixing Signal Under Weak And Moderate Feedback, Xiaojun Zhang, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo

Faculty of Informatics - Papers (Archive)

The spectrum characteristics of self-mixing signals observed in optical feedback self-mixing interferometry (OFSMI) is studied in this paper. The purpose is to provide guidance for the design of pre-processing techniques for eliminating noise or disturbance. The influence of two important parameters of the OFSMI system on the spectrum, that is, the optical feedback factor and the linewidth enhancment factor, are measured by means of Discrete Fourier transform (DFT). The simulated results show that, at a weak feedback, the OFSMI signals are strictly band limited in nature, with the cut-off frequencies being the vibration frequency and the fringe frequency respectively. Also …

Adaptive Self-Organisation Of Wireless Ad-Hoc Control Networks, Fazel Naghdy, Nathan Simiana

Faculty of Informatics - Papers (Archive)

A novel concept called Wireless ad-hoc Control Networks (WACNets), exploring an ad-hoc approach to networked distributed control, has been under study for the last five years in the research group. Such systems represent a new stage in the evolution of distributed control and monitoring. The work carried out in developing an adaptive self-organisation algorithm for WACNet is reported. The algorithm deploys a distance measure technique while satisfying the rules and assumptions developed for WACNet framework. The effectiveness of the algorithm is verified through computer simulation under a number of given scenarios. The results obtained show that the algorithm effectively drives …

Mathematical Analysis Of Self-Heating In Compost Piles, Harvinder S. Sidhu, Mark I. Nelson, Nadeem Ansari, Xiao Dong Chen

Faculty of Informatics - Papers (Archive)

We model the increase in temperature in compost piles or landfill sites due to micro-organisms undergoing exothermic reactions. The model incorporates the heat release due to biological activity within the pile and the heat release due to the oxidation of cellulosic materials. The heat release rate due to biological activity is modelled by a function which is a monotonic increasing function of temperature over a particular range and followed by a monotone decreasing function of temperature. This functionality represents the fact that micro-organisms die or become dormant at high temperatures. The heat release due to the oxidation reaction is modelled …

Sava: A Novel Self-Adaptive Vertical Handoff Algorithm For Heterogeous Wireless Networks, Min Liu, Zhong-Cheng Li, Xiao-Bing Guo, Eryk Dutkiewicz, Ming-Hui Wang

Faculty of Informatics - Papers (Archive)

The next generation wireless networking (4G) is envisioned as a convergence of different wireless access technologies with diverse levels of performance. Vertical handoff (VHO) is the basic requirement for convergence of different access technologies and has received tremendous attention from the academia and industry all over the world. During the VHO procedure, handoff decision is the most important step that affects the normal working of communication. In this paper, we propose a novel vertical handoff decision algorithm, self- adaptive VHO algorithm (SAVA), and compare its performance with conventional algorithms. SAVA synthetically considers the long term movement region and short term …

Spin-Wave Relaxation In Diluted Magnetic Semiconductors Within The Self-Consistent Green's Function Approach, J E. Bunder, Shih-Jye Sun, Hsiu-Hau Lin

Faculty of Informatics - Papers (Archive)

No abstract provided.

A Data-Fitting Approach For Displacements And Vibration Measurement Using Self-Mixing Interferometers, Yi Zhang, Jiangtao Xi, Joe F. Chicharo, Yanguang Yu

Faculty of Informatics - Papers (Archive)

This paper presents a signal processing approach for vibration measurement using self-mixing interferometer (SMI). Compared to existing approaches, the proposed approach is able to achieve an accuracy of λ/40 which significantly exceeds the accuracy limit associated with conventional simple SMI systems λ/4.