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Physical Sciences and Mathematics Commons™
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- Audio coding (3)
- Data compression (3)
- Levels (3)
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- Amicable sets (2)
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- AMS Classification 05B05. (1)
- AMS Subject Classification: 65F05 65G05 20B20. (1)
- Hall polynomial. (1)
- AMS Subject Classification: 05820. (1)
- High non-linearity. (1)
Articles 61 - 86 of 86
Full-Text Articles in Physical Sciences and Mathematics
Six D.O.F Haptic Rendered Simulation Of The Peg-In-Hole Assembly, Shen Dong, Fazel Naghdy, Yan Chen
Six D.O.F Haptic Rendered Simulation Of The Peg-In-Hole Assembly, Shen Dong, Fazel Naghdy, Yan Chen
Faculty of Informatics - Papers (Archive)
A new paradigm for programming of robotics manipulator to perform complex constrained motion tasks is being studied. The teaching of the manipulation skills to the machine starts by demonstmting those skills in a haptic -rendered virtual environment. Position and contact force and torque data generated in the virtual environment combined with a priori knowledge about the task is used to identify and learn the skills in the newly demonstrated tasks and then to reproduce them in the robotics system. The peg-in-hole insertion problem is used as a case study. In the ftrst implementation of the virtual manipulahon envlfonment, a three …
Application Of Nega-Cyclic Matrices To Generate Spreading Sequences, R. Ang, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki
Application Of Nega-Cyclic Matrices To Generate Spreading Sequences, R. Ang, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki
Faculty of Informatics - Papers (Archive)
In the paper, we present a new class of orthogonal bipolar spreading sequences designed based on Goethals-Seidel construction with nega-cyclic matrices. The sequences can be designed for any length equal to 4 (mod 8), and possess good correlation properties. In particular, their aperiodic autocorrelation characteristics are very good. That can be traded off for improvement in the cross-correlation performance using a diagonal modification method, as shown in the example.
Williamson-Hadamard Spreading Sequences For Ds-Cdma Applications, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki
Williamson-Hadamard Spreading Sequences For Ds-Cdma Applications, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki
Faculty of Informatics - Papers (Archive)
Orthogonal bipolar spreading sequences are used in direct sequence code division multiple acces (DS-CDMA) systems for both spectrum spreading and channel separation. The most commonly used sequences are Walsh-Hadamard sequences of lenghts being an integer power of 2. A construction based on Williamson's arrays leading to sequences of lengths N ≡ 4(mod 8) is presented in the paper. Aperiodic correlation characteristics, for example sequence sets of lengths 12-252 are presented. The correlation properties of the sequence sets are later improved using a diagonal modification technique.
Harmonics And Flicker Levels At A Sub-Transmission Substation: A Measurement Experience, D A. Robinson, Victor J. Gosbell, Sarath Perera, N Browne
Harmonics And Flicker Levels At A Sub-Transmission Substation: A Measurement Experience, D A. Robinson, Victor J. Gosbell, Sarath Perera, N Browne
Faculty of Informatics - Papers (Archive)
Proactive monitoring of power quality disturbance levels by electricity utilities is vital to allow cost-effective mitigation when disturbances are perceived to be approaching planning levels and also to protect the security of customer installations. Ensuring that disturbance levels are within limits at the HV and EHV points of supply of the network is essential if satisfactory levels downstream are to be maintained. This paper presents discussion on a power quality monitoring campaign performed at the sub-transmission point of supply of a distribution network with the objective of benchmarking background disturbance levels prior to modifications to the substation and to ensure …
Harmonic Planning Levels For Australian Distribution Systems, Victor J. Gosbell, Victor W. Smith, D A. Robinson, W Miller
Harmonic Planning Levels For Australian Distribution Systems, Victor J. Gosbell, Victor W. Smith, D A. Robinson, W Miller
Faculty of Informatics - Papers (Archive)
A modelling technique is developed for determining the harmonic voltage distribution across a distribution system when there is an equitable distribution of harmonic emission. The harmonic voltages at the 132kV and 415V levels are fixed to values based on IEC Compatibility and Planning Levels and the intermediate voltages determined. Studies are made of six systems, typical of Australian distribution practice, to examine the effect of choice of voltage level and system parameters over the harmonic range of 2-40. Based on the study, harmonic Planning Levels are recommended for application to Australian distribution systems.
A Transient Index For Reporting Power Quality Surveys, Victor J. Gosbell, Sarath Perera, D A. Robinson, Chandana Herath
A Transient Index For Reporting Power Quality Surveys, Victor J. Gosbell, Sarath Perera, D A. Robinson, Chandana Herath
Faculty of Informatics - Papers (Archive)
Impulsive transients are often blamed for the destruction of customer appliances. Advances in Power Quality (PQ) monitors will soon make it feasible to incorporate impulsive transients into routine power quality surveys. This paper considers how the transient events captured over a period at many sites may be reported in a simple but useful manner. The paper first summarizes a recent publication by some of the authors, which attempt to give a complete framework for the analysis of utility PQ data. This framework provides a basis for evaluating existing transient characterization practices as well as for the proposed new transient index …
A Study Of Continuous Pq Disturbance Levels In Mv/Lv Distribution Systems, Victor J. Gosbell, D A. Robinson
A Study Of Continuous Pq Disturbance Levels In Mv/Lv Distribution Systems, Victor J. Gosbell, D A. Robinson
Faculty of Informatics - Papers (Archive)
Distribution Network Service Providers need to be aware of the general variation of PQ disturbances across their network, from the sites as diverse as the MV bus bar of a zone substation, the end of a MV feeder, and at the near and far ends of LV mains. This paper develops an understanding of PQ variations across such a system from survey results correlated with approximate analysis used to assign a PQ disturbance ranking to each site. The work will concentrate on continuous PQ disturbances, defined as those due to load current effects, for example voltage deviations, unbalance, fluctuations and …
Affine Hecke Algebras, Cyclotomic Hecke Algebras And Clifford Theory, Arun Ram, Jacqueline Ramagge
Affine Hecke Algebras, Cyclotomic Hecke Algebras And Clifford Theory, Arun Ram, Jacqueline Ramagge
Faculty of Informatics - Papers (Archive)
We show that the Young tableaux theory and constructions of the irreducible representations of the Weyl groups of type A, B and D, Iwahori-Hecke algebras of types A, B, and D, the complex reflection groups G(r, p, n) and the corresponding cyclotomic Hecke algebras Hr,p,n, can be obtained, in all cases, from the affine Hecke algebra of type A. The Young tableaux theory was extended to affine Hecke algebras (of general Lie type) in recent work of A. Ram. We also show how (in general Lie type) the representations of general affine Hecke algebras can be constructed from the representations …
Current State Of Smes Work At The University Of Wollongong, Australia, R L Thompson, Christopher J. Hawley, Christopher David Cook, Steve Gower, Frank Darmann
Current State Of Smes Work At The University Of Wollongong, Australia, R L Thompson, Christopher J. Hawley, Christopher David Cook, Steve Gower, Frank Darmann
Faculty of Informatics - Papers (Archive)
The University of Wollongong (UoW) has received funding for the research and development of a high transition temperature (HTS) superconducting magnetic energy storage (SMES) device designed to operate at 40 K. This paper provides an update on work previously reported at AUPEC (2001) and summarises progress in the areas of computer assisted modelling, electromagnetic and thermal coil design, electronic control system, current leads and the cryogenic system. The proposed coil design for the SMES will be evaluated and discussed with respect to its advantages and limitations.
A 96 X 64 Intelligent Digital Pixel Array With Extended Binary Stochastic Arithmetic, Tarik Hammadou, Magnus Nilson, Amine Bermak, Philip Ogunbona
A 96 X 64 Intelligent Digital Pixel Array With Extended Binary Stochastic Arithmetic, Tarik Hammadou, Magnus Nilson, Amine Bermak, Philip Ogunbona
Faculty of Informatics - Papers (Archive)
A chip architecture that integrates an optical sensor and a pixel level processing element based on binary stochastic arithmetic is proposed. The optical sensor is formed by an array of fully connected pixels, and each pixel contains a sensing element and a Pulse Frequency Modulator (PFM) converting the incident light to bit streams of identical pulses. The processing element is based on binary stochastic arithmetic to perform signal processing operations on the focal plane VLSI circuit. A 96 x 64 CMOS image sensor is fabricated using 0.5pm CMOS technology and achieves 29 x 29pm pixel size at 15% fill factor.
Stereoscopic Panoramic Video Generation Using Centro-Circular Projection Technique, Chaminda Weerasinghe, Wanqing Li, Philip Ogunbona
Stereoscopic Panoramic Video Generation Using Centro-Circular Projection Technique, Chaminda Weerasinghe, Wanqing Li, Philip Ogunbona
Faculty of Informatics - Papers (Archive)
This paper presents a method of stereoscopic panoramic video generation including techniques for panorama projection, stitching and calibration for various depth planes. The methods described can be used on video sequences captured by an arrangement of multiple pairs of cameras or multiple stereoscopic cameras mounted on a regular polygonal shaped camera rig. Algorithms can also be used in combination or separately, for generating both stereoscopic and monoscopic video and still panoramas.
A Hybrid Optical Network Architecture Consisting Of Optical Cross Connects And Optical Burst Switches, Chuntung Chou, Farzad Safaei, P. Boustead, I. Ouveysi
A Hybrid Optical Network Architecture Consisting Of Optical Cross Connects And Optical Burst Switches, Chuntung Chou, Farzad Safaei, P. Boustead, I. Ouveysi
Faculty of Informatics - Papers (Archive)
Optical burst switches (OBSes) have been proposed to improve the utilization of a network of optical cross connect (OXCs). Current studies on OBS assume a network consisting of OBSes alone. While this is a reasonable assumption for evaluating a new technology, the question of how a network of OXCs can be evolved to a network of OBSes has not been studied. In this paper, we propose a hybrid architecture consisting of OBSes at the network edge and OXCs in the network core. This architecture allows carriers to gradually migrate from an OXC-based network to an OBS-based network with an improved …
Frame Analysis For Biorthogonal Cosine-Modulated Filterbanks, Alfred Mertins
Frame Analysis For Biorthogonal Cosine-Modulated Filterbanks, Alfred Mertins
Faculty of Informatics - Papers (Archive)
This paper addresses the efficient computation of frame bounds for cosine-modulated filterbanks. We derive explicit expressions for the eigenvalues of the frame operator that can be easily computed from the prototype's polyphase components. The number of channels and the downsampling factor may be even or odd, and the oversampling factor is supposed to be an integer. The analysis of low-delay, biorthogonal filterbanks; shows that prototypes solely designed to minimize the stopband energy may lead to wide open frames and, thus, to an undesirable numerical behavior. Because the computational cost of determining the frame bounds with the proposed method is very …
Scalable To Lossless Audio Compression Based On Perceptual Set Partitioning In Hierarchical Trees (Pspiht), M. Raad, Alfred Mertins, I. Burnett
Scalable To Lossless Audio Compression Based On Perceptual Set Partitioning In Hierarchical Trees (Pspiht), M. Raad, Alfred Mertins, I. Burnett
Faculty of Informatics - Papers (Archive)
The paper proposes a technique for scalable to lossless audio compression. The scheme presented is perceptually scalable and also provides for lossless compression. It produces smooth objective scalability, in terms of SegSNR, from lossy to lossless compression. The proposal is built around the introduced perceptual SPIHT algorithm, which is a modification of the SPIHT algorithm. Both objective and subjective results are reported and demonstrate both perceptual and objective measure scalability. The subjective results indicate that the proposed method performs comparably with the MPEG-4 AAC coder at 16, 32 and 64 kbps, yet also achieves a scalable-to-lossless architecture.
Asymptotics For General Fractionally Intergrated Processes With Applications To Unit Root Tests, Q. Wang, Yan-Xia Lin, C. M. Gulati
Asymptotics For General Fractionally Intergrated Processes With Applications To Unit Root Tests, Q. Wang, Yan-Xia Lin, C. M. Gulati
Faculty of Informatics - Papers (Archive)
In this paper, functional limit theorems for general fractional processes are established under quite weak conditions+ The results are then used to derive weak convergence of general nonstationary fractionally integrated processes and to characterize unit root distribution in a model with error being a fractional autoregressive moving average process or a nonstationary fractionally integrated process+
A Flat Ship Theory On Bow And Stern Flows, Song-Ping Zhu, Y. L. Zhang
A Flat Ship Theory On Bow And Stern Flows, Song-Ping Zhu, Y. L. Zhang
Faculty of Informatics - Papers (Archive)
An analytical solution of a two dimensional bow and stern flow model based on a flat ship theory is presented for the first time. The flat ship theory is a counterpart to Michell’s thin ship theory and leads to a mixed initial boundary value problem, which is usually difficult to solve analytically. Starting from the transient problem, we shall first show that a steady state is attainable at the large time limit. Then the steady problem is solved in detail by means of the Wiener Hopf technique and closed form farfield results are obtained for an arbitrary hull shape. Apart …
The Adoption Of E-Commerce By Microbusinesses, Katina Michael
The Adoption Of E-Commerce By Microbusinesses, Katina Michael
Faculty of Informatics - Papers (Archive)
In Australia, about 89 per cent of businesses have less than five employees. This equates to 1035 000 microbusinesses. What is important to note is that 637300 of these are non-employing businesses (i.e. sole proprietors) according to the Australian Bureau of Statistics (ABS). By studying these figures it becomes increasingly apparent what a challenging task the majority of business operators have in adopting and successfully integrating electronic commerce into their business. They only have their own resources and experiences to draw on and face a multitude of constraints such as time, money, lack of expertise and access to limited amounts …
The Automatic Identification Trajectory, Katina Michael
The Automatic Identification Trajectory, Katina Michael
Faculty of Informatics - Papers (Archive)
The top-secret ENIAC project, at the Moore School of Engineering at the University of Pennsylvania, was first made known to the public in February 1946. Reporters used 'anthropomorphic' and 'awesome characterisations' to describe the computer. In an article entitled 'The myth of the awesome thinking machine', Martin stated that the ENIAC was referred to in headlines as 'a child, a Frankenstein, a whiz kid, a predictor and controller of weather, and a wizard'.
Integrating Islands Of Information Through Crm, Katina Michael
Integrating Islands Of Information Through Crm, Katina Michael
Faculty of Informatics - Papers (Archive)
It was not so long ago that one would pull up into a service station and be greeted by an attendant who would customarily ask whether or not to fill up the car with petrol. Of course, today things have changed. Petrol station attendants have been replaced by something called 'self-service'. The customer is empowered and has the responsibility to fill up their own car with as much petrol as they want. A little extra effort perhaps but no one seems to mind, apart from the countless number of people who lost their jobs as attendants. What is noticeable, however, …
The Battle Against Security Attacks, Katina Michael
The Battle Against Security Attacks, Katina Michael
Faculty of Informatics - Papers (Archive)
Medium-to-large-sized companies are increasingly using their intranets to broadcast company-wide messages and store valuable information. Employees can choose to view multimedia- based messages from company executives, link to the latest product success stories, download the most recent technical specifications or refer to the most up-to-date pricing figures. Whatever the requirement, organisations have become very reliant upon electronic intra- and intercommunication methods. Whether it is sending an email with an attachment to a client, downloading information from the knowledge management system (KMS) or placing files in one another's public folders, employees now expect the technological capabilities to be available all the …
Barunga Music Online, A. Toshack, Katina Michael
Barunga Music Online, A. Toshack, Katina Michael
Faculty of Informatics - Papers (Archive)
Barunga Music is a fictitious company, used for the sole purpose of creating this case study:
Barunga Music is an organisation that records, markets and sells Aboriginal compositions. Barunga is a small business that operates a physical store based in Melbourne. The organisation was established in 1994 by Stephen Clark and business partner Daniel Stone. The company employs 10 staff members, including a part-time IT professional.
The Online Privacy Frontier, Katina Michael
The Online Privacy Frontier, Katina Michael
Faculty of Informatics - Papers (Archive)
Many web sites pride themselves on offering personalised customer service, but that really depends on the amount of information the online shopper is willing to give the online merchant. In most cases, unless a purchase is made or some other form of transaction is enacted, the online shopper will not declare their identity. How personalised can an experience be online if one entity decides to remain anonymous? The online merchant has little, if any, information to go on apart from perhaps a cookie that tells them that the visitor is a repeat visitor to that web site. The seller does …
The Rise Of The Wireless Internet, Katina Michael
The Rise Of The Wireless Internet, Katina Michael
Faculty of Informatics - Papers (Archive)
The introduction of the mobile phone revolutionised the way people traditionally communicated with one another. People suddenly became accessible independent of their location, at any time of the day or week. A salesperson in business for instance, who was always on the road could now be reached and could in turn make phone calls conveniently between customer meetings. Bundled with the basic mobile voice service was messaging in the form of voice or text. The latter has especially proven to be a useful and cost-effective method for conveying a short message. Collectively residential and business mobile subscribers use the short …
Spatial Statistics In The Presence Of Location Error With An Application To Remote Sensing Of The Environment, Noel A. Cressie, John Kornak
Spatial Statistics In The Presence Of Location Error With An Application To Remote Sensing Of The Environment, Noel A. Cressie, John Kornak
Faculty of Informatics - Papers (Archive)
Techniques for the analysis of spatial data have, to date, tended to ignore any effect caused by error in specifying the spatial locations at which measurements are recorded. This paper reviews the methods for adjusting spatial inference in the presence of data-location error, particularly for data that. have a continuous spatial index (geostatistical data). New kriging equations are developed and evaluated based on a simulation experiment. They are also applied to remote-sensing data from the Total Ozone Mapping Spectrometer instrument on the Nimbus-7 satellite, where the location error is caused by assignment of the data to their nearest grid-cell centers. …
Allocating Harmonic Emission To Mv Customers In Long Feeder Systems, D A. Robinson, Victor J. Gosbell
Allocating Harmonic Emission To Mv Customers In Long Feeder Systems, D A. Robinson, Victor J. Gosbell
Faculty of Informatics - Papers (Archive)
Previous work has attempted to find satisfactory methods for the allocation of harmonic current emission MV subsystems containing long feeders. It has been proposed that best use of the network's harmonic absorption capacity is made if the allocated current varies with the inverse square root of the harmonic impedance at the point of connection. It has been shown that an exact solution following this principle requires an impracticably large amount of data. Here it is assumed that each feeder supplied from a given substation has its load distributed uniformly and continuously along it, giving equations requiring only a modest amount …
Preliminary Design Of A High Tc Superconducting Persistent Mode Current Switch, Christopher J. Hawley, Dominic Cuiuri, Steve Gower
Preliminary Design Of A High Tc Superconducting Persistent Mode Current Switch, Christopher J. Hawley, Dominic Cuiuri, Steve Gower
Faculty of Informatics - Papers (Archive)
Persistent Mode Current Switches (PMCS) are made from coils of superconductor that in theory will provide zero conduction losses when closed. By causing a section of the superconductor to leave its superconducting state and become resistive, the switch is effectively opened. There are currently 3 methods to open a PMCS; 1) applying heat, 2) applying a magnetic field or 3) application of current above the critical current (Ic) of the tape. The first two methods are not suitable for power applications as the switching time is too slow. Recent work at the University of Wollongong and in literature has shown …