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Faculty of Informatics - Papers (Archive)

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Articles 1531 - 1560 of 2013

Full-Text Articles in Physical Sciences and Mathematics

A Hybrid Optical Network Architecture Consisting Of Optical Cross Connects And Optical Burst Switches, Chuntung Chou, Farzad Safaei, P. Boustead, I. Ouveysi Jan 2003

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 …

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Frame Analysis For Biorthogonal Cosine-Modulated Filterbanks, Alfred Mertins Jan 2003

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 …

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Scalable To Lossless Audio Compression Based On Perceptual Set Partitioning In Hierarchical Trees (Pspiht), M. Raad, Alfred Mertins, I. Burnett Jan 2003

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.

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Asymptotics For General Fractionally Intergrated Processes With Applications To Unit Root Tests, Q. Wang, Yan-Xia Lin, C. M. Gulati Jan 2003

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+

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A Flat Ship Theory On Bow And Stern Flows, Song-Ping Zhu, Y. L. Zhang Jan 2003

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 …

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The Adoption Of E-Commerce By Microbusinesses, Katina Michael Jan 2003

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 …

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The Automatic Identification Trajectory, Katina Michael Jan 2003

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'.

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Integrating Islands Of Information Through Crm, Katina Michael Jan 2003

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, …

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The Battle Against Security Attacks, Katina Michael Jan 2003

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 …

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Barunga Music Online, A. Toshack, Katina Michael Jan 2003

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.

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The Online Privacy Frontier, Katina Michael Jan 2003

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 …

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The Rise Of The Wireless Internet, Katina Michael Jan 2003

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 …

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Spatial Statistics In The Presence Of Location Error With An Application To Remote Sensing Of The Environment, Noel A. Cressie, John Kornak Jan 2003

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. …

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Allocating Harmonic Emission To Mv Customers In Long Feeder Systems, D A. Robinson, Victor J. Gosbell Jan 2003

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 …

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Preliminary Design Of A High Tc Superconducting Persistent Mode Current Switch, Christopher J. Hawley, Dominic Cuiuri, Steve Gower Jan 2003

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 …

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Current State Of Smes Work At The University Of Wollongong, Australia, R L Thompson, Christopher J. Hawley, Christopher David Cook, Steve Gower, Frank Darmann Jan 2003

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.

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Skill Acquisition In Transfer Of Manipulation Skills From Human To Machine Through A Haptic Virtual Environment, Y. Chen, F. Naghdy Dec 2002

Skill Acquisition In Transfer Of Manipulation Skills From Human To Machine Through A Haptic Virtual Environment, Y. Chen, F. Naghdy

Faculty of Informatics - Papers (Archive)

A new paradigm for programming a robotics manipulator is developed. It is intended that the teaching of the machine will begin with the necessary skills being demonstrated by the human operator in a virtual environment with tactile sensing (haptics). 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. The overall concept is described. The methodologies developed to …

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Routing In Mobile Ad Hoc Networks With Global Knowledge, D. Platt Nov 2002

Routing In Mobile Ad Hoc Networks With Global Knowledge, D. Platt

Faculty of Informatics - Papers (Archive)

This paper describes a method of routing in mobile ad hoc networks. The problem is exacerbated by the fact that the radio links between the nodes of the network are continually being made and broken. The method consists of using the known connections to construct a "map" of the network which is intended to reproduce the geographical layout of the network at any time. An algorithm is described which finds a route from one node to another by always attempting to move geographically closer to the destination at every hop. This produces nearly optimal performance with very short computation time. …

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Improved Utilisation In Ip Networks Using Multiple Path Routing, D. Platt Nov 2002

Improved Utilisation In Ip Networks Using Multiple Path Routing, D. Platt

Faculty of Informatics - Papers (Archive)

This paper considers routing in an IP network running a routing protocol such as OSPF It takes as a benchmark a routing scheme. which computes a single lowest cost path between every source/destination pair. It proposes two more schemes which each generate two routes for each source/destination pair. The second scheme uses the present lowest cost route and the previous lowest cost route, different from the present one. The third scheme uses the present lowest cost route and re-computes a route by removing all the links used in the first route and using the Dijkstra algorithm. A number of tests …

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Scalable Routing Strategy For Dynamic Zones-Based Manets, Mehran Abolhasan, Tadeusz A. Wysocki, E. Dutkiewicz Nov 2002

Scalable Routing Strategy For Dynamic Zones-Based Manets, Mehran Abolhasan, Tadeusz A. Wysocki, E. Dutkiewicz

Faculty of Informatics - Papers (Archive)

This paper presents a new routing strategy for mobile ad hoc networks, called dynamic zone-based topology routing protocol (DZTR). We introduce new strategies to maintain up-to-date intrazone and interzone topology information at each node. We also propose a GPS-based location tracking mechanism, which reduces route discovery area and the number of nodes queried to find the required destination. Our routing strategy has been designed to work with a dynamic zone, which contains a set of member nodes. Every node outside a zone is called a single-state node. We perform theoretical performance analysis, which shows that our network topology creation process …

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Remote Collaborative Teaching For Computer Science, A. Fuller, Penelope Mcfarlane, K. Lam Nov 2002

Remote Collaborative Teaching For Computer Science, A. Fuller, Penelope Mcfarlane, K. Lam

Faculty of Informatics - Papers (Archive)

Like many western universities, the University of Wollongong (Australia) is offering degrees to an increasing number of offshore students. Their usual offshore teaching model involves intensive delivery of course material. Disadvantages of this model include the apparent secondary nature of the offshore academic's role and its unsuitability for technical subjects. In this paper, the authors discuss experiments using Internet technologies to overcome those disadvantages.

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Enhancing Team Teaching With Webct, Gene Awyzio, Penelope Mcfarlane, A. Fuller Nov 2002

Enhancing Team Teaching With Webct, Gene Awyzio, Penelope Mcfarlane, A. Fuller

Faculty of Informatics - Papers (Archive)

Team teaching has been shown to benefit both students and faculty and we have previously shown a class management package (WebCT) supports an interdisciplinary team environment. However, what happens when the team constituency changes? This paper explores our experience with this situation as we depend on WebCT to facilitate adapting to such a change, further highlighting that WebCT is an integral member of our team.

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Experiences Using Case Studies To Teach Risk, A. Fuller, Khin Than Win, L. Dei Nov 2002

Experiences Using Case Studies To Teach Risk, A. Fuller, Khin Than Win, L. Dei

Faculty of Informatics - Papers (Archive)

Most software development projects today are facing increased risks. Despite this risk management planning is virtually nonexistent, as managers have not been trained in risk management. Few current software engineering curricula provide comprehensive coverage of risk, nor any practical experience in risk assessment. In this paper we discuss our experience using case studies to teach risk as part of a final year course in software process management with a view to determining the effectiveness of the particular case studies. This experience will be used as a foundation for implementing the full semester course in 2003.

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Asymptotic Solitons For A Higher-Order Modified Korteweg–De Vries Equation, Timothy R. Marchant Oct 2002

Asymptotic Solitons For A Higher-Order Modified Korteweg–De Vries Equation, Timothy R. Marchant

Faculty of Informatics - Papers (Archive)

Solitary wave interaction for a higher-order modified Korteweg–de Vries (mKdV) equation is examined. The higher-order mKdV equation can be asymptotically transformed to the mKdV equation, if the higher-order coefficients satisfy a certain algebraic relationship. The transformation is used to derive the higher-order two-soliton solution and it is shown that the interaction is asymptotically elastic. Moreover, the higher-order phase shifts are derived using the asymptotic theory. Numerical simulations of the interaction of two higher-order solitary waves are also performed. Two examples are considered, one satisfies the algebraic relationship derived from the asymptotic theory, and the other does not. For the example …

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Traffic Engineering For Mpls-Based Virtual Private Networks, Chuntung Chou Oct 2002

Traffic Engineering For Mpls-Based Virtual Private Networks, Chuntung Chou

Faculty of Informatics - Papers (Archive)

This paper considers the traffic engineering of MPLS-based virtual private networks (VPNs) with multiple classes of service. We focus on two main issues. Firstly, we point out that the one LSP per ingress-egress pair constraint can be relaxed for the case of MPLS-based VPNs due to the ease in classifying flows on a per-VPN basis. This allows us to use LSP with finer granularity and thus better load balancing. Secondly, we point out that the single objective traffic engineering formulations proposed in literature address only one particular aspect of the traffic engineering problem. We propose a multiobjective traffic engineering problem …

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Spanning The 4 Kbps Divide Using Pulse Modeled Residual, J Lukasiak, I. Burnett Oct 2002

Spanning The 4 Kbps Divide Using Pulse Modeled Residual, J Lukasiak, I. Burnett

Faculty of Informatics - Papers (Archive)

This paper reports a scalable method for coding the LP residual. The scalable method is capable of increasing the accuracy of the reconstructed speech from a parametric representation at low rates to a more accurate waveform matched representation at higher rates. The method entails pitch length segmentation, decomposition into pulsed and noise components and modeling of the pulsed components using a fixed shape pulse model in a closed-loop, analysis by synthesis system.

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Scalable Decomposition Of Speech Waveforms, J Lukasiak, I. Burnett Oct 2002

Scalable Decomposition Of Speech Waveforms, J Lukasiak, I. Burnett

Faculty of Informatics - Papers (Archive)

Decomposition of speech signals into periodic and noise components is widely used in speech coding to facilitate efficient compression. Existing decomposition schemes are too inflexible to model transient changes in the speech signal, require high delay or produce a large parameter set that is not scalable to low rates. This paper proposes a technique that requires only a single frame of speech and produces a scalable decomposition. The latter allows reconstruction accuracy to be varied according to the bit rate available.

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The Analysis Of Speech Codecs Using Psychoacoustic Measures, M. Raad, C. H. Ritz, I. Burnett, Alfred Mertins Oct 2002

The Analysis Of Speech Codecs Using Psychoacoustic Measures, M. Raad, C. H. Ritz, I. Burnett, Alfred Mertins

Faculty of Informatics - Papers (Archive)

This paper analyses two narrowband speech codecs, the 4.8 kbit/s FS1016 coder and the 8 kbit/s G729 coder, using objective psychoacoustic measures. Four measures are used: loudness, sharpness, roughness and tonality. The results show sharpness and roughness as the two major contributing factors to the subjective difference between the two coders.

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Extending Waveform Interpolation To Wideband Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak Oct 2002

Extending Waveform Interpolation To Wideband Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak

Faculty of Informatics - Papers (Archive)

This paper investigates the extension of waveform interpolation (WI) to wideband speech coding. Included is an analysis of the evolutionary behaviour of wideband speech and the consequences for WI. We highlight problems associated with direct application of the classical WI algorithm applied to wideband speech.

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On Full Orthogonal Designs In Order 56, S. Georgiou, C. Koukouvinos, Jennifer Seberry Oct 2002

On Full Orthogonal Designs In Order 56, S. Georgiou, C. Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We find new full orthogonal designs in order 56 and show that of 1285 possible OD(56; s1, s2, s3, 56—s1—s2-s3) 163 are known, of 261 possible OD(56; s1, s2, 56—s1—s2) 179 are known. All possible OD(56; s1, 56 — s1) are known.

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