Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

None

Discipline
Keyword
Publication Year
Publication

Articles 991 - 1020 of 2377

Full-Text Articles in Physical Sciences and Mathematics

Handling Significant Scale Difference For Object Retrieval In A Supermarket, Yuhang Zhang, Lei Wang, Richard Hartley, Hongdong Li Dec 2012

Handling Significant Scale Difference For Object Retrieval In A Supermarket, Yuhang Zhang, Lei Wang, Richard Hartley, Hongdong Li

Dr Lei Wang

No abstract provided.


A Novel Video-Based Smoke Detection Method Using Image Separation, Hongda Tian, Wanqing Li, Lei Wang, Philip Ogunbona Dec 2012

A Novel Video-Based Smoke Detection Method Using Image Separation, Hongda Tian, Wanqing Li, Lei Wang, Philip Ogunbona

Dr Lei Wang

In the state-of-the-art video-based smoke detection methods, the representation of smoke mainly depends on the visual information in the current image frame. In the case of light smoke, the original background can be still seen and may deteriorate the characterization of smoke. The core idea of this paper is to demonstrate the superiority of using smoke component for smoke detection. In order to obtain smoke component, a blended image model is constructed, which basically is a linear combination of background and smoke components. Smoke opacity which represents a weighting of the smoke component is also defined. Based on this model, …


Positive Semidefinite Metric Learning With Boosting, Chunhua Shen, Junae Kim, Lei Wang, Anton Hengel Dec 2012

Positive Semidefinite Metric Learning With Boosting, Chunhua Shen, Junae Kim, Lei Wang, Anton Hengel

Dr Lei Wang

No abstract provided.


What Has My Classifier Learned? Visualizing The Classification Rules Of Bag-Of-Feature Model By Support Region Detection, Lingqiao Liu, Lei Wang Dec 2012

What Has My Classifier Learned? Visualizing The Classification Rules Of Bag-Of-Feature Model By Support Region Detection, Lingqiao Liu, Lei Wang

Dr Lei Wang

In the past decade, the bag-of-feature model has established itself as the state-of-the-art method in various visual classification tasks. Despite its simplicity and high performance, it normally works as a black box and the classification rule is not transparent to users. However, to better understand the classification process, it is favorable to look into the black box to see how an image is recognized. To fill this gap, we developed a tool called Restricted Support Region Set (RSRS) Detection which can be utilized to visualize the image regions that are critical to the classification decision. More specifically, we define the …


Perceptions Of The Ordering Process Of Online Grocery Stores, Mark Freeman Dec 2012

Perceptions Of The Ordering Process Of Online Grocery Stores, Mark Freeman

Dr Mark Freeman

No abstract provided.


Does Technology Use Change When In A Developed Country? A Case Study Of Libyans In Australia, Fouad Elgahwash, Mark Freeman Dec 2012

Does Technology Use Change When In A Developed Country? A Case Study Of Libyans In Australia, Fouad Elgahwash, Mark Freeman

Dr Mark Freeman

With developing countries now gaining access to modern banking services for their customers, research is needed to understand how developing countries will adapt to these changes. Since the 1980s, in the Arabic region, technological expansion has occurred with a focus on trade and services offered by industries &¿ recently the banking sector has started to develop banking services through mobile devices and the Internet to improve customer relationships. In particular, the banking sector is an information intensive industry and aims to be at the forefront of advanced use of Information and Communication Technologies (ICTs). One common trend is increasing the …


Fire, Wind And Water: Social Networks In Natural Disasters, Mark Freeman Dec 2012

Fire, Wind And Water: Social Networks In Natural Disasters, Mark Freeman

Dr Mark Freeman

No abstract provided.


Monotremes Provide A Key To Understanding The Evolutionary Significance Of Epididymal Sperm Maturation, Brett Nixon, Russell Jones, Jean-Louis Dacheux, Heath Ecroyd Dec 2012

Monotremes Provide A Key To Understanding The Evolutionary Significance Of Epididymal Sperm Maturation, Brett Nixon, Russell Jones, Jean-Louis Dacheux, Heath Ecroyd

Heath Ecroyd

"It has been widely accepted that mammalian spermatozoa are infertile when they leave the testes and require a period of maturation in both the epididymis and the female reproductive tract before acquiring the ability to fertilize an oocyte. However, the necessity for such a complex process of posttesticular sperm maturation appears to be unique to mammals because it is well established that these processes do not directly influence the fertilizing ability of the spermatozoa of birds, reptiles, and other lower vertebrates. Because of their key evolutionary position and form of reproduction, we contend that monotremes (platypus and echidna) provide a …


Nmr Spectroscopy Of 14-3-3zeta Reveals A Flexible C-Terminal Extension: Differentiation Of The Chaperone And Phosphoserine-Binding Activities Of 14-3-3zeta, H Fu, Danielle Williams, Heath Ecroyd, John Carver, Lixin Zhang, Huanqin Dai, Joanna Woodcock, K Goodwin Dec 2012

Nmr Spectroscopy Of 14-3-3zeta Reveals A Flexible C-Terminal Extension: Differentiation Of The Chaperone And Phosphoserine-Binding Activities Of 14-3-3zeta, H Fu, Danielle Williams, Heath Ecroyd, John Carver, Lixin Zhang, Huanqin Dai, Joanna Woodcock, K Goodwin

Heath Ecroyd

Intracellular 14-3-3 proteins bind to many proteins, via a specific phosphoserine motif, regulating diverse cellular tasks including cell signalling and disease progression. The 14-3-3 isoform is a molecular chaperone, preventing the stressinduced aggregation of target proteins in a manner comparable with that of the unrelated sHsps (small heat-shock proteins). 1H-NMR spectroscopy revealed the presence of a flexible and unstructured C-terminal extension, 12 amino acids in length, which protrudes from the domain core of 14-3-3 and is similar in structure and length to the C-terminal extension of mammalian sHsps. The extension stabilizes 14-3-3, but has no direct role in chaperone action. …


Enhanced Molecular Chaperone Activity Of The Small Heat-Shock Protein Alphab-Cystallin Following Covalent Immobilization Onto A Solid-Phase Support, V Bellotti, Heath Ecroyd, J Carver, H J Griesser, B Thierry, J G Shapter, S S Griesser, S Giorgetti, M R Nussio, J A Gerrard, J Garvey Dec 2012

Enhanced Molecular Chaperone Activity Of The Small Heat-Shock Protein Alphab-Cystallin Following Covalent Immobilization Onto A Solid-Phase Support, V Bellotti, Heath Ecroyd, J Carver, H J Griesser, B Thierry, J G Shapter, S S Griesser, S Giorgetti, M R Nussio, J A Gerrard, J Garvey

Heath Ecroyd

The well-characterized small heat-shock protein, alphaB-crystallin, acts as a molecular chaperone by interacting with unfolding proteins to prevent their aggregation and precipitation. Structural perturbation (e.g., partial unfolding) enhances the in vitro chaperone activity of alphaB-crystallin. Proteins often undergo structural perturbations at the surface of a synthetic material, which may alter their biological activity. This study investigated the activity of alphaB-crystallin when covalently bound to a support surface; alphaB-crystallin was immobilized onto a range of solid material surfaces, and its characteristics and chaperone activity were assessed. Immobilization was achieved via a plasma-deposited thin polymeric interlayer containing aldehyde surface groups and reductive …


Design Maintenance In Process Eco-Systems, Tri Kurniawan, Aditya Ghose, Hoa Dam, Lam-Son Le, Tiancheng Zhang Dec 2012

Design Maintenance In Process Eco-Systems, Tri Kurniawan, Aditya Ghose, Hoa Dam, Lam-Son Le, Tiancheng Zhang

Dr Hoa Dam

This paper addresses the problem of managing business process changes at the design level within a complex business process repository. We argue that a formal process eco-systems view can provide a particular useful solution to the problem in which their inter-process relationships can be properly described. Our intent is to build a modular infrastructure to support change management in process eco-systems by leveraging a change propagation approach that would maintain the inter-process relationships. This permits us to propagate the changes, made on a particular process, to the rest of the processes for maintaining the relationship equilibrium of such eco-system. Our …


On The Effect Of Multiple Access Interference In A Space Time Spreading Time Hopping Ppm Uwb System, Peter Vial, Beata Wysocki, Tadeusz Wysocki, Montserrat Ros, David Stirling Dec 2012

On The Effect Of Multiple Access Interference In A Space Time Spreading Time Hopping Ppm Uwb System, Peter Vial, Beata Wysocki, Tadeusz Wysocki, Montserrat Ros, David Stirling

Dr Peter Vial

This study investigates the effect of multiple sources using STS across a Time-Hopping-PPM Modulation that is over an UWB Saleh-Valenzuela channel with each source using two transmit antennas. We model and analyze this system, showing that the presence of such MAI results in a significant degradation in BER performance. Simulation results show that for strong signal strength of interfering MAI signals degradation in BER performance is observed for the cases where we have five and 10 distinct MAI sources present when using Walsh-Hadamard thirty two chip spreading sequences. Using simulation, we investigate the use of other sets of orthogonal spreading …


Design And Simulation Of A Ds-Th-Uwb System Using Simulink/Matlab For First Arriving Rays In A Non Line Of Sight Wireless Scenario, Peter Vial Dec 2012

Design And Simulation Of A Ds-Th-Uwb System Using Simulink/Matlab For First Arriving Rays In A Non Line Of Sight Wireless Scenario, Peter Vial

Dr Peter Vial

An Ultra Wideband system was developed using Simulink in previous work. Using this developed model for Ultra Wideband (UWB) Pulse Position Modulation (PPM) within Simulink, we apply Direct Sequence Walsh codes across Time Hopping Patterns to smooth out the spectral characteristics with Pulse Position Modulation. A non-line of sight Saleh-Valenzuela (SV) model is used to characterize the wireless channel. The system is described and results are presented for the scenario where the first arriving rays are used to detect the transmitted message. For this non-optimum technique (in that for non line of sight the strongest signal rays are available after …


Embedded Internet Laboratory, Fazel Naghdy, Peter Vial, N Taylor Dec 2012

Embedded Internet Laboratory, Fazel Naghdy, Peter Vial, N Taylor

Dr Peter Vial

No abstract provided.


Telecommunications Network Management Applications In An Educational Environment, Ibrahim Raad, Peter Vial, W. Raad, Keni Popovski Dec 2012

Telecommunications Network Management Applications In An Educational Environment, Ibrahim Raad, Peter Vial, W. Raad, Keni Popovski

Dr Peter Vial

No abstract provided.


Space-Time-Frequency Trellis Coding For Multiband Ofdm Ultra Wideband Wireless Systems, Phuc Ngoc Le, Le Chung Tran, Farzad Safaei Dec 2012

Space-Time-Frequency Trellis Coding For Multiband Ofdm Ultra Wideband Wireless Systems, Phuc Ngoc Le, Le Chung Tran, Farzad Safaei

Dr Le Chung Tran

In this paper, the application of space time trellis codes to multiband orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) systems is investigated. We propose a coding scheme that could fully exploit all the available channel diversity, including space diversity, frequency diversity and inter-subband diversity. Performance of the proposed system is compared with that of the conventional MB-OFDM UWB system in terms of frame error rate (FER). Simulation results show that this system outperforms the conventional one. As an example, an improvement of at least 5 dB at FER=1E-2 could be achieved over the IEEE 802.15.3a channel modes of CM1 and …


A Study Of Information Security Awareness And Practices In Saudi Arabia, Abdulaziz Alarifi, Holly Tootell, Peter Hyland Dec 2012

A Study Of Information Security Awareness And Practices In Saudi Arabia, Abdulaziz Alarifi, Holly Tootell, Peter Hyland

Dr Holly Tootell

Although the Web, cell phoneand cloud computing put a world of information at our fingertips, that information is under constant threat from cyber vandals and hackers. While awareness of information threats is growing in the Western world, in places like Saudi Arabia, information security is very poor. Unlike Western pluralistic democracies, Saudi Arabia is a highly-censored country, with a patriarchical and tribal culture, which may influence its poor information security rating. This paper examines the level of information security awareness (ISA) among the general public in Saudi Arabia, using an anonymous online survey, based on instruments produced by the Malaysian …


Privacy- The Times They Are A-Changin', M.G. Michael, Katina Michael Dec 2012

Privacy- The Times They Are A-Changin', M.G. Michael, Katina Michael

Professor Katina Michael

This special section is dedicated to privacy in the information age. Since the rise of mobile social media in particular and the advent of cloud computing few can dispute that the times have changed. Privacy is now understood in context, and within a framework that is completely different to what it once was. The right to be let alone physically seemingly has been replaced by the right to give away as much information as you want virtually. What safeguards can be introduced into such a society? We cannot claim to wish for privacy as a right if we ourselves do …


A Survey Of Some Mathematical Results For Highly Frictional Granular Materials, Grant Cox, Ngamta Thamwattana, James Hill Dec 2012

A Survey Of Some Mathematical Results For Highly Frictional Granular Materials, Grant Cox, Ngamta Thamwattana, James Hill

Dr Ngamta Thamwattana

Recently the authors have exploited the notion of a highly frictional granular material to derive analytical solutions for certain problems. Generally, we use the term highly frictional granular material to refer to those materials which possess an angle of internal friction such that the trigonometric sine of the angle of internal friction is close to unity. There are many granular materials for which this is the case, such as black and brown coal and limestone powder. For such materials formal perturbation solutions can be derived for which the zeroth-order solution corresponds to an angle of internal friction precisely equal to …


Coulomb-Mohr Granular Materials: Quasi-Static Flows And The Highly Frictional Limit, James Hill, Grant Cox, Ngamta Thamwattana, Scott Mccue Dec 2012

Coulomb-Mohr Granular Materials: Quasi-Static Flows And The Highly Frictional Limit, James Hill, Grant Cox, Ngamta Thamwattana, Scott Mccue

Dr Ngamta Thamwattana

One approach to modeling fully developed shear flow of frictional granular materials is to use a yield condition and a flow rule, in an analogous way to that commonly employed in the fields of metal plasticity and soil mechanics. Typically, the yield condition of choice for granular materials is the CoulombMohr criterion, as this constraint is relatively simple to apply but at the same time is also known to predict stresses that are in good agreement with experimental observations. On the other hand, there is no strong agreement within the engineering and applied mechanics community as to which flow rule …


Mechanics Of Fullerene-Carbon Nanotube Bundle Oscillators, James Hill, Ngamta Thamwattana, Duangkamon Baowan, Barry Cox Dec 2012

Mechanics Of Fullerene-Carbon Nanotube Bundle Oscillators, James Hill, Ngamta Thamwattana, Duangkamon Baowan, Barry Cox

Dr Ngamta Thamwattana

Carbon nanostructures, such as nanotubes and fullerenes, are of considerableinterest to a wide range of research communities. Owing to their unique properties, a numberof applications involving these structures have been proposed, one of which is the so-callednano-scaled oscillators, for which the resultant oscillatory frequencies are in the gigahertzrange. The phenomena of the gigahertz oscillations have also led to the possible creation offuture devices, such as ultra-fast optical filters and ultra-sensitive nano-antennae. In thispaper we present recent developments in this area and review the authors recent work,where we investigate the mechanics of a new type of gigahertz oscillator comprising afullerene C60 …


Mathematical Modelling For A C60 Carbon Nanotube Oscillator, Barry Cox, Ngamta Thamwattana, James Hill Dec 2012

Mathematical Modelling For A C60 Carbon Nanotube Oscillator, Barry Cox, Ngamta Thamwattana, James Hill

Dr Ngamta Thamwattana

The discovery of fullerenes C60 and carbon nanotubes has created an enormous impact on nanotechnology. Because of their unique mechanical and electronic properties, such as low weight, high strength, flexibility and thermal stability, fullerenes C60 and carbon nanotubes are of considerable interest to researchers from many scientific areas. One problem that has attracted much attention is the creation of gigahertz oscillators. While there are difficulties for micromechanical oscillators, or resonators, to reach a frequency in the gigahertz range, it is possible for nanomechanical systems to achieve this. A number of studies have found that the sliding of the inner-shell inside …


Orientation Of A Benzene Molecule Inside A Carbon Nanotube, Thien Tran-Duc, Ngamta Thamwattana, James Hill Dec 2012

Orientation Of A Benzene Molecule Inside A Carbon Nanotube, Thien Tran-Duc, Ngamta Thamwattana, James Hill

Dr Ngamta Thamwattana

Benzene molecules confined in carbon nanotubes of varying radii are employed as semiconductors in electronic nanodevices, and their orientation determines the electrical properties of the system. In this paper, we investigate the interaction energy of all the possible configurations of a benzene molecule inside various carbon nanotubes and then we determine the equilibrium configuration. We adopt the continuous approach together with the semi-empirical Lennard-Jones potential function to model van der Waals interaction between a benzene molecule and a carbon nanotube. This approach results in an analytical expression, which accurately approximates the interaction energy and can be readily used to generate …


Continuum Modelling Of Gigahertz Nano-Oscillators, James Hill, Ngamta Thamwattana, Duangkamon Baowan, Tamsyn Hilder, Barry Cox Dec 2012

Continuum Modelling Of Gigahertz Nano-Oscillators, James Hill, Ngamta Thamwattana, Duangkamon Baowan, Tamsyn Hilder, Barry Cox

Dr Ngamta Thamwattana

Fullerenes and carbon nanotubes are of considerable interest throughout many scientific areas due to their unique and exceptional properties, such as low weight, high strength, flexibility, high thermal conductivity and chemical stability. These nanostructures have many potential applications in nano-devices. One concept that has attracted much attention is the creation of nano-oscillators, which can produce frequencies in the gigahertz range, for applications such as ultra-fast optical filters and nano-antennae. In this paper, we provide the underlying mechanisms of the gigahertz nano-oscillators and we review some recent results derived by the authors using the Lennard-Jones potential together with the continuum approach …


Spherical And Spheroidal Fullerenes Entering Carbon Nanotubes, James Hill, Ngamta Thamwattana, Barry Cox Dec 2012

Spherical And Spheroidal Fullerenes Entering Carbon Nanotubes, James Hill, Ngamta Thamwattana, Barry Cox

Dr Ngamta Thamwattana

A continuous model of a fullerene inside a carbon nanotube and for which both the fullerene and carbon nanotube are treated as smooth surfaces with uniform atomic number densities and the van der Waals interaction is formulated using a 6-12 Lennard-Jones potential. From the model we derive acceptance conditions and suction energies for C60, C70 and C80 fullerenes. We show that for these systems where the fullerenes are not accepted by the nanotube, then the suction energy is particularly sensitive to the equatorial semi-axis length b. Alternatively, when the nanotube does accept the fullerene then an approximately equal suction energy …


Modelling Adsorption Of A Water Molecule Into Various Pore Structures Of Silica Gel, Duangkamon Baowan, Ngamta Thamwattana Dec 2012

Modelling Adsorption Of A Water Molecule Into Various Pore Structures Of Silica Gel, Duangkamon Baowan, Ngamta Thamwattana

Dr Ngamta Thamwattana

Silica gel is widely used in commercial applications as a water adsorbent due to its properties including hydrothermally stable, high water sorption capacity, low regeneration temperature, low cost and wide range of pore diameters. Since the water sorption capacity of silica gel strongly depends on the pore size and structure, which can be controlled during synthesis, this paper study the effect of pore shapes and dimensions of silica gel upon the adsorption of a water molecule aiming at maximising the water sorption capacity. In particular, we consider three types of pore structures, namely cylindrical, square prismatic and conical pores. On …


Magnetic Field Driven Nano Tippe Top, James Hill, Ngamta Thamwattana, Yue Chan Dec 2012

Magnetic Field Driven Nano Tippe Top, James Hill, Ngamta Thamwattana, Yue Chan

Dr Ngamta Thamwattana

We investigate the motion of a nano tippe top, which is formed from a C60 fullerene, and which is assumed to be spinning on either a graphene sheet or the interior of a single-walled carbon nanotube. We assume no specific geometric configuration for the top, however for example, the nano tippe top might be formed by joining a fullerene C60 with a small segment of a smaller radius carbon nanotube. We assume that it is spinning on a graphene sheet or a carbon nanotube surface only as a means of positioning and isolating the device, and the only effect of …


Modelling Peptide Nanotubes For Artificial Ion Channels, Ngamta Thamwattana, Barry Cox, Fainida Rahmat Dec 2012

Modelling Peptide Nanotubes For Artificial Ion Channels, Ngamta Thamwattana, Barry Cox, Fainida Rahmat

Dr Ngamta Thamwattana

We investigate the van der Waals interaction of D,L-Ala cyclopeptide nanotubes and various ions, ion&¿water clusters and C60 fullerenes, using the Lennard-Jones potential and a continuum approach which assumes that the atoms are smeared over the peptide nanotube providing an average atomic density. Our results predict that Li + , Na + , Rb + and Cl &¿ ions and ion&¿water clusters are accepted into peptide nanotubes of 8.5 Å internal diameter whereas the C60 molecule is rejected. The model indicates that the C60 molecule is accepted into peptide nanotubes of 13 Å internal diameter, suggesting that the interaction energy …


The Analysis Of Stratified Multiple Responses, Ivy Liu, Thomas Suesse Dec 2012

The Analysis Of Stratified Multiple Responses, Ivy Liu, Thomas Suesse

Dr Thomas Suesse

Surveys often contain qualitative variables for which respondents may select any number of the outcome categories. For instance, for the question “What type of contraception have you used?” with possible responses (oral, condom, lubricated condom, spermicide, and diaphragm), respondents would be instructed to select as many of the outcomes that apply. This situation is known as multiple responses. When the data includes stratification variables, we discuss two approaches: (1) the “GEE” approach which uses logit models directly applying the generalized estimating equations (GEE) method (Liang and Zeger, 1986); and (2) the “GMH” approach which extends the generalized Mantel–Haenszel type estimators …


Methods For Parameter Identification In Oscillatory Networks And Application To Cortical And Thalamic 600 Hz Activity, Thomas Suesse, Jens Haueisen, Lutz Leistritz, Herbert Witte, Bernd Hilgenfeld Dec 2012

Methods For Parameter Identification In Oscillatory Networks And Application To Cortical And Thalamic 600 Hz Activity, Thomas Suesse, Jens Haueisen, Lutz Leistritz, Herbert Witte, Bernd Hilgenfeld

Dr Thomas Suesse

No abstract provided.