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Full-Text Articles in Social and Behavioral Sciences

Representations Of Cuntz-Pimsner Algebras, Neal J. Fowler, Paul S. Muhly, Iain Raeburn Jan 2003

Representations Of Cuntz-Pimsner Algebras, Neal J. Fowler, Paul S. Muhly, Iain Raeburn

Faculty of Engineering and Information Sciences - Papers: Part A

Let X be a Hilbert bimodule over a C * -algebra A. We analyse the structure of the associated Cuntz-Pimsner algebra X and related algebras using representation-theoretic methods. In particular, we study the ideals (I) in X induced by appropriately invariant ideals I in A, and identify the quotients X/(I) as relative Cuntz-Pimsner algebras of Muhly and Solel. We also prove a gauge-invariant uniqueness theorem for X, and investigate the relationship between X and an alternative model proposed by Doplicher, Pinzari and Zuccante.


Delta-Ferrite Recovery Structures In Low-Carbon Steels, Rian Dippenaar, Dominic Phelan Jan 2003

Delta-Ferrite Recovery Structures In Low-Carbon Steels, Rian Dippenaar, Dominic Phelan

Faculty of Engineering and Information Sciences - Papers: Part A

The development of delta-ferrite recovery substructures in low-carbon steels has been observed in-situ utilizing laser scanning confocal microscopy (LSCM). Well-developed sub-boundaries with interfacial energies much smaller than that of delta-ferrite grain boundaries formed following transformation from austenite to delta-ferrite on heating. It is proposed that transformation stresses associated with the austenite to delta-ferrite phase transformation generate dislocations that subsequently recover into sub-boundaries by a process of polygonization. Experimental evidence in support of this proposal was found in a ferritic stainless steel. Thermal cycling through the high-temperature delta-ferrite/austenite/delta-ferrite phase transformation leads to the development of a well-defined recovery substructure, which, in …


Chain Entanglements And Fracture Energy In Interfaces Between Immiscible Polymers, Leonardo Silvestri, Hugh Ralph Brown, Stefano Carra, Sergio Carra Jan 2003

Chain Entanglements And Fracture Energy In Interfaces Between Immiscible Polymers, Leonardo Silvestri, Hugh Ralph Brown, Stefano Carra, Sergio Carra

Faculty of Engineering and Information Sciences - Papers: Part A

It is a very well-known experimental fact that the toughness of interfaces obtained by joining pairs of immiscible glassy polymers is strongly correlated to the interfacial width. Several models have been proposed in the literature to estimate the fracture energy of these interfaces, but the agreement displayed with the experimental data cannot be considered satisfactory. In this paper a new model is proposed for polymers with molecular weight higher than the critical value for the onset of entanglements. The model is based on a precise and realistic calculation of the areal density of entangled strands across the interface, that is …


Higher-Rank Graphs And Their C*-Algebras, Iain Raeburn, Aidan Sims, Trent Yeend Jan 2003

Higher-Rank Graphs And Their C*-Algebras, Iain Raeburn, Aidan Sims, Trent Yeend

Faculty of Engineering and Information Sciences - Papers: Part A

We consider the higher-rank graphs introduced by Kumjian and Pask as models for higher-rank Cuntz-Krieger algebras. We describe a variant of the Cuntz-Krieger relations which applies to graphs with sources, and describe a local convexity condition which characterises the higher-rank graphs that admit a nontrivial Cuntz-Krieger family. We then prove versions of the uniqueness theorems and classifications of ideals for the C*-algebras generated by Cuntz-Krieger families.


Detection Of Carbon Monoxide Within The Magellanic Bridge, E Muller, L Staveley-Smith, William Zealey Jan 2003

Detection Of Carbon Monoxide Within The Magellanic Bridge, E Muller, L Staveley-Smith, William Zealey

Faculty of Engineering and Information Sciences - Papers: Part A

The Mopra 22-m and SEST 15-m telescopes have been used to detect and partially map a region of 12CO(1-0) line emission within the Magellanic Bridge, a region lying between the Large and Small Magellanic Clouds (LMC and SMC, respectively). The emission appears to be embedded in a cloud of neutral hydrogen, and is in the vicinity of an IRAS source. The CO emission region is found to have a 60 μm/100 μm flux density ratio typical for 12CO(1-0) detections within the SMC, although it has a significantly lower 12CO brightness and velocity width. These suggest that the …


Rank-One Convexity Implies Quasi-Convexity On Certain Hypersurfaces, Nirmalendu Chaudhuri, Stefan Muller Jan 2003

Rank-One Convexity Implies Quasi-Convexity On Certain Hypersurfaces, Nirmalendu Chaudhuri, Stefan Muller

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.


Countably Generated Hilbert Modules, The Kasparov Stabilisation Theorem, And Frames In Hilbert Modules, Iain Raeburn, Shaun J. Thompson Jan 2003

Countably Generated Hilbert Modules, The Kasparov Stabilisation Theorem, And Frames In Hilbert Modules, Iain Raeburn, Shaun J. Thompson

Faculty of Engineering and Information Sciences - Papers: Part A

We consider a class of countably generated Hilbert modules in which the generators are multipliers of the module, and prove a version of the Kasparov Stabilisation Theorem for these modules. We then extend recent work of Frank and Larson on frames in Hilbert modules.


Bounds For The Best Constant In An Improved Hardy-Sobolev Inequality, Nirmalendu Chaudhuri Jan 2003

Bounds For The Best Constant In An Improved Hardy-Sobolev Inequality, Nirmalendu Chaudhuri

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.


Issues For Connection Of Distributed Generation In Rural/Remote Power Systems, Kashem M. Muttaqi, Gerard Ledwich, Michael Negnevitsky Jan 2003

Issues For Connection Of Distributed Generation In Rural/Remote Power Systems, Kashem M. Muttaqi, Gerard Ledwich, Michael Negnevitsky

Faculty of Engineering and Information Sciences - Papers: Part A

Connection of distributed generation (DG) into a distribution grid system affects the normal operation, control and protection of the distribution system. This paper addresses some of the technical issues arisen due to the addition of generation to a rural/remote distribution network. In this paper, a voltage controlled rotary DG is modelled to operate in the line of voltage sensitivity for maximum voltage improvement. A scenario-based study on DG operation and control has been conducted and recommendations for effective operation of DG presented. An investigation on barriers to inclusion of utility owned and customer owned DG has been carried out and …


Theoretical And Experimental Investigation Of Descending Salt Plumes From A Circular Source, Apichart Chaengbamrung, Paul Cooper, Peter W. Wypych, Ajit R. Godbole Jan 2003

Theoretical And Experimental Investigation Of Descending Salt Plumes From A Circular Source, Apichart Chaengbamrung, Paul Cooper, Peter W. Wypych, Ajit R. Godbole

Faculty of Engineering and Information Sciences - Papers: Part A

This paper describes work in the first part of an ongoing research programme on the generation and dispersion of fume from hot metal processes, a challenging industrial ventilation problem. This phase of the study involves research into a salt solution plume generated from an area source and descending into quiescent water. This is a 'cold flow' analogue of a thermal plume ascending in quiescent air. Experiments are described whereby the velocity and concentration profiles in the plume are determined using video footage and particle-tracking software, and a conductivity probe with digital traversing mechanism, respectively. Results from a transient numerical simulation …


Compiler Optimization And Ordering Effects On Vliw Code Compression, Montserrat Ros, Peter Sutton Jan 2003

Compiler Optimization And Ordering Effects On Vliw Code Compression, Montserrat Ros, Peter Sutton

Faculty of Engineering and Information Sciences - Papers: Part A

Code size has always been an important issue for all embedded applications as well as larger systems. Code compression techniques have been devised as a way of battling bloated code; however, the impact of VLIW compiler methods and outputs on these compression schemes has not been thoroughly investigated. This paper describes the application of single- and multipleinstruction dictionary methods for code compression to decrease overall code size for the TI TMS320C6xxx DSP family. The compression scheme is applied to benchmarks taken from the Mediabench benchmark suite built with differing compiler optimization parameters. In the single instruction encoding scheme, it was …


Image Retrieval With Svm Active Learning Embedding Euclidean Search, Lei Wang, Kap Luk Chan, Yap Peng Tan Jan 2003

Image Retrieval With Svm Active Learning Embedding Euclidean Search, Lei Wang, Kap Luk Chan, Yap Peng Tan

Faculty of Engineering and Information Sciences - Papers: Part A

Image retrieval with relevance feedback suffers from the small sample problem. Recently, SVM active learning has been proposed to tackle this problem, showing promising results. However, a small but sufficient number of initially labelled samples are still required to ensure the subsequent active learning efficient and good retrieval performance. In the existing method, the user is asked to label more images before active learning starts. In this paper, a method of embedding Euclidean search into SVM active learning is proposed. With the help of Euclidean search, not only the adverse effect on retrieval performance due to lack of initially labelled …


Australian Online Supermarket Usability, Mark Freeman, Peter N. Hyland, Jeffrey Soar Jan 2003

Australian Online Supermarket Usability, Mark Freeman, Peter N. Hyland, Jeffrey Soar

Faculty of Engineering and Information Sciences - Papers: Part A

The issue of usability plays a vital role in the success of an online store. However, to date there has been limited published research into this issue and there has been no research conducted into multiple item purchasing. There is much competition in the grocery shopping industry between the two major physical supermarket chains in Australia, Woolworths and Coles, both in traditional stores and online. Online, the major competitor is ShopFast, which does not have a traditional supermarket storefront to complement its online operations. The purpose of this study was to conduct a comparative analysis into the usability of ordering …


Www Sites Vs. Applications Software: The Dais Model, Lejla Vrazalic, Peter N. Hyland Jan 2003

Www Sites Vs. Applications Software: The Dais Model, Lejla Vrazalic, Peter N. Hyland

Faculty of Engineering and Information Sciences - Papers: Part A

Since the advent and widespread use of the Internet, it has become apparent that there are significant differences between applications software and WWW sites which warrant a re-examination of HCI design and evaluation methods. Previous research has identified and documented the factors which differentiate between applications software and WWW sites, however a well defined model of these differences and their origins was not available. This paper defines such a model of Distinguishing Attributes for Informational Sites (DAIS). © 2003 ACM.


Smoothness And Locality For Nonunital Spectral Triples, Adam C. Rennie Jan 2003

Smoothness And Locality For Nonunital Spectral Triples, Adam C. Rennie

Faculty of Engineering and Information Sciences - Papers: Part A

To deal with technical issues in noncommuntative geometry for nonunital algebras, we introduce a useful class of algebras and their modules. Thes algebras and modules allo us to extend all of the smoothness results for spectral triples to the nonunital case. In addition, we show that smooth spectral tiples are closed under the C- functional calculus of self-adjoint elements. In the final section we show that our algebras allow the formulation of Poincare Duality and that the algebras of smooth spectral triples are H-unital.


Local Compactness In Free Topological Groups, Peter Nickolas, Mikhail Tkachenko Jan 2003

Local Compactness In Free Topological Groups, Peter Nickolas, Mikhail Tkachenko

Faculty of Engineering and Information Sciences - Papers: Part A

We show that the subspace An(X) of the free Abelian topological group A(X) on a Tychonoff space X is locally compact for each n ω if and only if A2(X) is locally compact if an only if F2(X) is locally compact if and only if X is the topological sum of a compact space and a discrete space. It is also proved that the subspace Fn(X) of the free topological group F(X) is locally compact for each n …


Glass Formation In A (Ti,Zr,Hf)-(Cu,Ni,Ag)-Al High-Order Alloy System By Mechanical Alloying, L C. Zhang, Z Q. Shen, Jian Xu Jan 2003

Glass Formation In A (Ti,Zr,Hf)-(Cu,Ni,Ag)-Al High-Order Alloy System By Mechanical Alloying, L C. Zhang, Z Q. Shen, Jian Xu

Faculty of Engineering and Information Sciences - Papers: Part A

In this work, glass formation under high-energy ball milling was investigated for a (Ti0.33Zr0.33Hf0.33)50(Ni0.33Cu0.33Ag0.33)40Al10 high-order alloy system with equiatomic substitution for early and late transition-metal contents. For comparison, an amorphous alloy ribbon with the same composition was prepared using the melt-spinning method as well. Structural features of the samples were characterized using x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. Mechanical alloying resulted in a glassy alloy similar to that obtained by melt spinning. However, the glass formation was incomplete, and a …


The Surface Area Preserving Mean Curvature Flow, James Mccoy Jan 2003

The Surface Area Preserving Mean Curvature Flow, James Mccoy

Faculty of Engineering and Information Sciences - Papers: Part A

We adopt similar notation to Huisken in [Hu1] and [Hu2]. Let M be an n-dimensional Riemannian manifold.


Effect Of Deformation Schedule On The Microstructure And Mechanical Properties Of A Thermomechanically Processed C-Mn-Si Transformation-Induced Plasticity Steel, I B. Timokhina, P D. Hodgson, E V. Pereloma Jan 2003

Effect Of Deformation Schedule On The Microstructure And Mechanical Properties Of A Thermomechanically Processed C-Mn-Si Transformation-Induced Plasticity Steel, I B. Timokhina, P D. Hodgson, E V. Pereloma

Faculty of Engineering and Information Sciences - Papers: Part A

Thermomechanical processing simulations were performed using a hot-torsion machine, in order to develop a comprehensive understanding of the effect of severe deformation in the recrystallized and nonrecrystallized austenite regions on the microstructural evolution and mechanical properties of the 0.2 wt pct C-1.55 wt pct Mn-1.5 wt pct Si transformation-induced plasticity (TRIP) steel. The deformation schedule affected all constituents (polygonal ferrite, bainite in different morphologies, retained austenite, and martensite) of the multiphased TRIP steel microstructure. The complex relationships between the volume fraction of the retained austenite, the morphology and distribution of all phases present in the microstructure, and the mechanical properties …


High-Resolution Hi Observations Of The Western Magellanic Bridge, E Muller, L Staveley-Smith, William Zealey, S Stanimirovic Jan 2003

High-Resolution Hi Observations Of The Western Magellanic Bridge, E Muller, L Staveley-Smith, William Zealey, S Stanimirovic

Faculty of Engineering and Information Sciences - Papers: Part A

The 21-cm line emission from a 7 × 6 deg2 region east of and adjoining the Small Magellanic Cloud (SMC) has been observed with the Australia Telescope Compact Array and the Parkes telescopes. This region represents the westernmost part of the Magellanic Bridge, a gas-rich tail extending ∼14° to the Large Magellanic Cloud. A rich and complex neutral hydrogen (H i) structure containing shells, bubbles and filaments is revealed. On the larger scale, the H i of the Bridge is organized into two velocity components. This bimodality, which appears to originate in the SMC, converges to a single velocity …


Intersection Type Systems And Logics Related To The Meyer-Routley System B+, Martin W. Bunder Jan 2003

Intersection Type Systems And Logics Related To The Meyer-Routley System B+, Martin W. Bunder

Faculty of Engineering and Information Sciences - Papers: Part A

Some, but not all, closed terms of the lambda calculus have types; these types are exactly the theorems of intuitionistic implicational logic. An extension of these simple (→) types to intersection (or →∧) types allows all closed lambda terms to have types. The corresponding →∧ logic, related to the Meyer–Routley minimal logic B+ (without ∨), is weaker than the →∧ fragment of intuitionistic logic. In this paper we provide an introduction to the above work and also determine the →∧ logics that correspond to certain interesting subsystems of the full →∧ type theory.


Actions Of Z^K Associated To Higher Rank Graphs, Alexander Kumjian, David Pask Jan 2003

Actions Of Z^K Associated To Higher Rank Graphs, Alexander Kumjian, David Pask

Faculty of Engineering and Information Sciences - Papers: Part A

An action of Zk is associated to a higher rank graph Λ satisfying a mild assumption. This generalizes the construction of a topological Markov shift arising from a non-negative integer matrix. We show that the stable Ruelle algebra of Λ is strongly Morita equivalent to C(Λ). Hence, if Λ satisfies the aperiodicity condition, the stable Ruelle algebra is simple, stable and purely infinite.


Comparing Particle Swarms For Tracking Extrema In Dynamic Environments, Xiaodong Li, Hoa K. Dam Jan 2003

Comparing Particle Swarms For Tracking Extrema In Dynamic Environments, Xiaodong Li, Hoa K. Dam

Faculty of Engineering and Information Sciences - Papers: Part A

This work presents a comparative study of particle swarm models on their abilities to track extrema in dynamic environments. A standard PSO, two randomized PSOs, and a fine-grained PSO are evaluated in non-trivial multimodal dynamic environments involving small constant step changes, different large step changes, and chaotic step changes of the extrema. DF1 proposed by Morrison and De Jong is used to generate these three types of dynamics (1999). Our results indicate that PSO and its variants are able to perform reasonably well in a 2-dimensional variable space, whereas perform well to a less extent in a 10-dimensional variable space. …


Bootstrapping Svm Active Learning By Incorporating Unlabelled Images For Image Retrieval, Lei Wang, Kap Luk Chan, Zhihua Zhang Jan 2003

Bootstrapping Svm Active Learning By Incorporating Unlabelled Images For Image Retrieval, Lei Wang, Kap Luk Chan, Zhihua Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

The performance of image retrieval with SVM active learning is known to be poor when started with few labelled images only. In this paper, the problem is solved by incorporating the unlabelled images into the bootstrapping of the learning process. In this work, the initial SVM classifier is trained with the few labelled images and the unlabelled images randomly selected from the image database. Both theoretical analysis and experimental results show that by incorporating unlabelled images in the bootstrapping, the efficiency of SVM active learning can be improved, and thus improves the overall retrieval performance.


Australian Transport And Greenhouse Gas Reduction Targets, Philip G. Laird Jan 2003

Australian Transport And Greenhouse Gas Reduction Targets, Philip G. Laird

Faculty of Engineering and Information Sciences - Papers: Part B

Transport greenhouse gas emissions have increased by about 24 per cent since 1990-91 making transport the fastest growing contributor of all sources of greenhouse gas emissions in Australia. This paper compares the energy efficiency of different modes of transport for freight and passenger tasks. If demand for road vehicle travel was managed and growth in passenger and freight tasks was picked up by the more energy efficient public transport and rail, Australia would begin to reduce its greenhouse gas emissions and move closer to achieving its greenhouse gas target.