Physical Sciences and Mathematics Commons^™

It Offshoring Risks And Governance Capabilities, Akemi T. Chatfield, Padmaharsha Wanninayaka

Faculty of Informatics - Papers (Archive)

IT offshoring or offshore outsourcing is a fast growing trend that is worldwide and continuing. Driven by the competitive pressure to reduce IT costs, firms in developed countries opt to buy IT services from offshore service providers in developing countries, which provide comparative advantage in lower labour costs and skilled workforce. While much has been written about its relative costs and benefits, there is a lack of comprehensive research on risks of IT offshoring. This research aims to identify IT offshoring risks based on a comprehensive review of the literature and content analysis. It also aims to map those risks …

Generalised Linear Mixed Model Analysis Via Sequential Monte Carlo Sampling, Y Fan, D S. Leslie, M P. Wand

Faculty of Informatics - Papers (Archive)

We present a sequential Monte Carlo sampler algorithm for the Bayesian analysis of generalised linear mixed models (GLMMs). These models support a variety of interesting regression-type analyses, but performing inference is often extremely difficult, even when using the Bayesian approach combined with Markov chain Monte Carlo (MCMC). The Sequential Monte Carlo sampler (SMC) is a new and general method for producing samples from posterior distributions. In this article we demonstrate use of the SMC method for performing inference for GLMMs. We demonstrate the effectiveness of the method on both simulated and real data, and find that sequential Monte Carlo is …

Finding Symmetries By Incorporating Initial Conditions As Side Conditions, J. M. Goard

Faculty of Informatics - Papers (Archive)

It is generally believed that in order to solve initial value problems using Lie symmetry methods, the initial condition needs to be left invariant by the infinitesimal symmetry generator that admits the invariant solution. This is not so. In this paper we incorporate the imposed initial value as a side condition to find ‘infinitesimals’ from which solutions satisfying the initial value can be recovered, along with the corresponding symmetry generator.

Lie Symmetry Methods In Finance: An Example Of The Bond Pricing Equation, Joanna M. Goard

Faculty of Informatics - Papers (Archive)

Using Lie’s classical method of group invariants, new solutions are found for the valuation of zero-coupon bonds. In finding the solutions, the model for the underlying short-term interest rate assumes a realistic time-dependent, mean-reverting drift form and a power-law volatility.

An Operational Model For A Well-Stirred Membrane Bioreactor: Reactor Performance Analysis, Mark Nelson, Harvinder Sidhu, Soji Adesina

Faculty of Informatics - Papers (Archive)

We investigate the behavior of a reaction described by Michaelis-Menten kinetics in an immobilised enzyme reactor (IER). The IER is treated as a well-stirred flow reactor, in which the bound and unbounded enzyme species are immobilized and therefore constrained to remain within the reaction vessel. The product species leaves the bioreactor either in the reactor outflow or by permeating through the semi-permeable reactor wall. We explore how the concentration of recovered product and the reactor productivity vary with process parameters, particularly those associated with the separation of the product from the substrate through the semi-permeable reactor wall. We show that …

Formal Concept Analysis For E-Learning, Ghassan Beydoun

Faculty of Informatics - Papers (Archive)

We capture student interactions in an e-learning community to construct a semantic web (SW) to create a collective meta-knowledge structure guiding students as they search the existing knowledge corpus. We use formal concept analysis (FCA) as a knowledge acquisition tool to process the students virtual surfing trails to express and exploit the dependencies between web-pages to yield subsequent and more effective focused search results. We mirror social navigation and bypass the cumbersome manual annotation of webpages and at the same time paralleling social navigation for knowledge. We present our system KAPUST2 (Keeper and Processor of User Surfing Trails) which constructs …

Chord4s: A P2p-Based Decentralised Service Discovery Approach, Qiang He, Jun Yan, Yun Yang, Ryszard Kowalczyk, Hai Jin

Faculty of Informatics - Papers (Archive)

Service-oriented computing is emerging as a paradigm for developing distributed applications. A critical issue of utilising service-oriented computing is to have a scalable, reliable and robust service discovery mechanism. However, traditional service discovery methods using centralised registries can easily suffer from problems such as performance bottleneck and vulnerability to failures in the large scalable service network, thus functioning abnormally. To address these problems, this paper proposes a peer-to-peer based decentralised service discovery approach named Chord4S. Chord4S utilises the data distribution and lookup capabilities of the popular Chord to distribute and discover services in a decentralised manner. Data availability is further …

Towards An Enterprise Business Process Architecture Standard, George Koliadis, Aditya K. Ghose, Srinivas Padmanabhuni

Faculty of Informatics - Papers (Archive)

An effective process architecture helps provide a high-level blueprint of the complexity underlying an enterprise, which is used by executive committees during key decision and change processes. As existing service standards focus on co-ordination, they fall short in describing the motivational structure depicted in such models. In order to progress towards standardization in this area of complexity, we discuss the practicality of a process architecture, and present a set of 22 questions that can be used in the functional evaluation and construction of a process architecture. We use these questions to evaluate the current “state-of-the-art” in business process architecture. We …

Modelling Quality And Spatial Characteristics For Autonomous E-Service Peers, Jun Shen, Shuai Yuan

Faculty of Informatics - Papers (Archive)

In this paper, we present an autonomous and scalable WSMO-based methodology to describe quality of service (QoS) and geographic features of e-services in a peer-to-peer based environment. To fully explore the usability of service mining and categorisation, we designed an algorithm to select the most appropriate peers to improve effective service composition.

A Practical Geographic Ontology For Spatial Web Services, Shuai Yuan, Jun Shen, Jun Yan

Faculty of Informatics - Papers (Archive)

The application of ontology in Web services context for dynamic discovery, autonomous composition, invocation and monitoring has been deemed as very promising in semantic Web based enterprise application integration and m-commerce. There are many initiatives aiming to realize pervasive services to enable effective enactment of better quality of services, such as sensitiveness on service locations. The traditional WSDL is hardly qualified enough to tackle new challenges such as accurate representation of the non-functional properties of services. Hence, OWL-S came up with an effectual approach to facilitating semantic service description, dynamic composition, on-the-fly execution, and many other tasks. In this paper, …

Mining E-Services In P2p-Based Workflow Enactments, Shuai Yuan, Jun Shen

Faculty of Informatics - Papers (Archive)

This paper aims to explore the feasible mining and proper selection of QoS-aware services for a P2P-based business process enactment framework, and enhance the relevant workflow prototype.

Through observing and analysing unpredictable dynamic changes which commonly exist in e-service workflow, we propose a set of QoS specifications and monitoring mechanisms in a P2P workflow framework. These specifications are an evolving extension of services’ description with semantic Web facilitators for P2P-based e-services.

It has been demonstrated that our QoS-OWL approach can be effectively used to describe and exploit e-services, particularly in decentralised environment. QoS-OWL is also able to provide the deliberation …

A Flexible And Reasonable Mechanism For Self-Interested Agent Team Forming, Q. Bai, Minjie Zhang

Faculty of Informatics - Papers (Archive)

As social entities, intelligent agents need to collaborate with others regardless of whether they are cooperative or self interested. Compared with cooperative agents, collaborations among self-interested agents are more complex and dynamic due to the selfish features. Self-interested agents are impelled to cooperate with others by their individual goals. In an agent team composed of self-interested agents, "common" goals of agents may change to be conflicted as the environment changes.

Non-Optimal Receiver For Space Time Spreading Across A Time Hopping Over Ultra Wideband Ppm, Peter James Vial, Beata J. Wysocki, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

A novel non-optimal chip based technique is proposed to use two antennas to transmit data across a Direct Sequence Time Hopping Ultra Wideband dual antenna wireless communication system to a single receiver. The spread data is sent over the independent channels using the Space Time Spreading technique to encode the chips which are sent on each antenna simultaneously. A hard decision is made at each chip of the spreading code received based on the known Channel State Information which Pulse Position Modulated signal was received from each antenna. The paper shows that by adapting the Space Time Spreading technique to …

New Orthogonal Designs From Weighing Matrices, Ilias Kotsireas, Christos Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

In this paper we show the existence of new orthogonal designs, based on a number of new weighing matrices of order 2n and weights 2n − 5 and 2n−9 constructed from two circulants. These new weighing matrices were constructed recently by establishing various patterns on the locations of the zeros in a potential solution, in conjunction with the power spectral density criterion. We also demonstrate that some of these new orthogonal designs, the ones that are full, can be used to construct inequivalent Hadamard matrices.

A Spatially Aware Rfid-Enhanced Wireless Sensor Network, Dheeraj Klair, Kwan-Wu Chin, Raad Raad, Darryn Lowe

Faculty of Informatics - Papers (Archive)

Radio frequency identification (RFID) systems are becoming increasingly popular for automatic object identification and supply chain management. Wide acceptance of this technology has led to several new areas of research, one of which is RFID-enhanced wireless sensor networks (WSNs). Such networks have the ability to self-organize, identify tagged objects, perform localization, and carry out searches; all of which are enablers of pervasive computing. This paper therefore presents various challenges to creating such networks, and describes our recent research on energy efficient RFID tag reading protocols.

Calibrating Mean-Reverting Jump Diffusion Models: An Application To The Nsw Electricity Market, Jamie Alcock, J. M. Goard, Tony Vassallo

Faculty of Informatics - Papers (Archive)

[extract] In recent years the Australian National Electricity Market (the NEM) has been undergoing the transition to a fully deregulated marketplace. In December 1998, for the first time, the wholesale price of electricity was subject to market forces. The NEM includes the Queensland, New South Wales, Victorian, South australian, Tasmanian and Australian Capital Territory electricity markets. Almost 8 million end users are supplied by the world's longest interconnected power system, and the NEM trades up to $7 billion of electricity annually.

Power-Law And Stable Distributions Of Bgp Paths, Julien Clement, Kwan-Wu Chin

Faculty of Informatics - Papers (Archive)

This paper presents two new properties of BGP routes. First, it shows that the frequency of autonomous systems (ASs) appearing in path vectors follow a Power-Law relationship. Secondly, it shows that path lengths can be characterized accurately by stable distributions. The main implication of these properties is that it allows the creation of realistic forwarding tables for simulation studies. Moreover, they extend previous works that have thus far only shown Power-Law relationships exhibited by ASs degree.

On The Viability And Performance Of Dns Tunneling, Tom Van Leijenhorst, Kwan-Wu Chin, Darryn Lowe

Faculty of Informatics - Papers (Archive)

DNS tunnels are network covert channels that allow the transmission of arbitrary data using the DNS infrastructure. Users can use such tunnels to hide their communication sessions in order to bypass local security and accounting policies. Hence, it is important that we investigate the viability and performance of DNS tunneling. Our results show that clients can obtain up to 110 KB/s in throughput, and delays as low as 150ms. These results, however, incur very high overheads. In the worst case, clients generate up to 2000% more traffic!

Are There Hilbert-Style Pure Type Systems?, Martin Bunder, Willibrordus Dekkers

Faculty of Informatics - Papers (Archive)

For many a natural deduction style logic there is a Hilbert-style logic that is equivalent to it in that it has the same theorems (i.e. valid judgements with empty contexts). For intuitionistic logic, the axioms of the equivalent Hilbert-style logic can be propositions which are also known as the types of the combinators I, K and S. Hilbert-style versions of illative combinatory logic have formulations with axioms that are actual type statements for I, K and S. As pure type systems (PTSs)are, in a sense, equivalent to systems of illative combinatory logic, it might be thought that Hilbert-style PTSs (HPTSs) …

Modelling Social Networks As Authorised Domains With Decay, Nicholas Sheppard, Reihaneh Safavi-Naini

Faculty of Informatics - Papers (Archive)

Sharing multimedia among friends and acquaintances is a common practice that, in appropriate settings, need not be detrimental to the interests of copyright owners. In this paper, we propose a model for sharing multimedia based on the notion of an acquaintance domain whose members will have access to the domain owner’s multimedia. Membership of an acquaintance domain is determined by the closeness of a relationship – where “closeness” can be defined by factors such as the frequency of visits – and membership of the domain deteriorates as the relationship becomes more distant. We have made an implementation of the proposal …

A Hierarchical Learning Network For Face Detection With In-Plane Rotation, Fok Hing Chi Tivive, Abdesselam Bouzerdoum

Faculty of Informatics - Papers (Archive)

This paper presents a scale and rotation invariant face detection system. The system employs a hierarchical neural network, called SICoNNet, whose processing elements are governed by the nonlinear mechanism of shunting inhibition. The neural network is used as a face/nonface classifier that can handle in-plane rotated patterns. To train the network as a rotation invariant face classifier, an enhanced bootstrap training technique is developed, which prevents bias towards the nonface class. Furthermore, a multi-resolution processing is employed for scale invariance: an image pyramid is formed through subsampling and face detection is performed at each scale of the pyramid using an …

Multivariate Autoregressive Modelling Of Multichannel Reverberant Speech, Eva Cheng, Ian Burnett, Christian Ritz

Faculty of Informatics - Papers (Archive)

Recent research in speech localization and dereverberation introduced processing of the multichannel linear prediction (LP) residual of speech recorded with multiple microphones. This paper investigates the novel use of intra- and inter-channel speech prediction by proposing the use of a multichannel LP model derived from multivariate autoregression (MVAR), where current LP approaches are based on univariate autoregression (AR). Experiments were conducted on simulated anechoic and reverberant synthetic speech vowels and real speech sentences; results show that, especially at low reverberation times, the MVAR model exhibits greater prediction gains from the residual signal, compared to residuals obtained from univariate AR models …

Schengen Information System Ii: The Balance Between Civil Liberties, Security And Justice, Katina Michael, M G. Michael

Faculty of Informatics - Papers (Archive)

This paper investigates the application of the Schengen Information System (SIS) in the European Union and the balance between civil liberties, security and justice. It provides an overview of the SIS, technical issues related to the maintenance of the SIS, and transnational legal issues in the context of national security and public policy.

A Spatial Squeezing Approach To Ambisonic Audio Compression, Bin Cheng, Christian Ritz, I. Burnett

Faculty of Informatics - Papers (Archive)

Spatially squeezed surround audio coding (S3AC) has been previously shown to provide efficient coding with perceptually accurate soundfield reconstruction when applied to ITU 5.1 multichannel audio. This paper investigates the application of S3AC to the coding of Ambisonic audio recordings. Traditional ambisonics achieve compression and backward compatibility through the use of the UHJ matrixing approach to obtain a stereo signal. In this paper the relationship to Ambisonic B-format signals is described and alternative approaches that derive a stereo or mono-downmix signal based on S3AC are presented and evaluated. The mono-downmix approach utilizes side information consisting of spatial cues that are …

Binaural Reproduction Of Spatially Squeezed Surround Audio, Bin Cheng, Christian Ritz, Ian Burnett

Faculty of Informatics - Papers (Archive)

Spatially Squeezed Surround Audio Coding (S³AC) has been previously proposed as an efficient approach to multi-channel spatial audio coding with stereo/mono backward compatibility. This paper presents a binaural reproduction scheme that exploits source localisation information in the S³AC squeezed soundfield or S³AC cues to simulate surround audio scene over headphones. The approach utilises interpolated HRTFs to bring the S³AC advantages of accurate, localised sound sources to stereo headphone systems. The integration of the HRTF approach to reproduction also exploits human localisation ability to reduce interpolation complexity. Subjective experiments demonstrate that accurate localisation …

C*-Algebras Associated To Coverings Of K-Graphs, Alexander Kumjian, David A. Pask, Aidan Sims

Faculty of Informatics - Papers (Archive)

A covering of k-graphs (in the sense of Pask-Quigg- Raeburn) induces an embedding of universal C∗-algebras. We show how to build a (k + 1)-graph whose universal algebra encodes this embedding. More generally we show how to realise a direct limit of k-graph algebras under embeddings induced from coverings as the universal algebra of a (k +1)-graph. Our main focus is on computing the K-theory of the (k+1)-graph algebra from that of the component k-graph algebras.

Examples of our construction include a realisation of the Kirchberg algebra Pn whose K-theory is opposite to that of On, and a class of …

Format-Independent Rich Media Delivery Using The Bitstream Binding Language, Joseph Thomas-Kerr, I. Burnett, Christian Ritz

Faculty of Informatics - Papers (Archive)

Several recent standards address virtual containers for rich multimedia content: collections of media with metadata describing the relationships between them and providing an immersive user experience. While these standards - which include MPEG-21 and TVAnytime - provide numerous tools for interacting with rich media objects, they do not provide a framework for streaming or delivery of such content. This paper presents the bitstream binding language (BBL), a format-independent tool that describes how multimedia content and metadata may be bound into delivery formats. Using a BBL description, a generic processor can map rich content (an MPEG-21 digital item, for example) into …

Quality Information Retrieval For The World Wide Web, Milly W. Kc, Markus Hagenbuchner, Ah Chung Tsoi

Faculty of Informatics - Papers (Archive)

The World Wide Web is an unregulated communication medium which exhibits very limited means of quality control. Quality assurance has become a key issue for many information retrieval services on the Internet, e.g. web search engines. This paper introduces some quality evaluation and assessment methods to assess the quality of web pages. The proposed quality evaluation mechanisms are based on a set of quality criteria which were extracted from a targeted user survey. A weighted algorithmic interpretation of the most significant user quoted quality criteria is proposed. In addition, the paper utilizes machine learning methods to produce a prediction of …

Abnormal Behavior Detection Using A Multi-Modal Stochastic Learning Approach, Philippa M. Lyons-Wall, Abdesselam Bouzerdoum, Son Lam Phung, Azeddine Beghdadi

Faculty of Informatics - Papers (Archive)

This paper presents a new approach to trajectory-based abnormal behavior detection (ABD). While existing techniques include position in the feature vector, we propose to estimate the probability distribution locally at each position, hence reducing the dimensionality of the feature vector. Local information derived from accumulated knowledge for a particular position is integrated in the distribution enabling context-based decision for ABD. A stochastic competitive learning algorithm is employed to estimate the local distributions of the feature vector and the location of the distribution modes. The proposed algorithm is tested on the detection of driving under the influence of alcohol. The performance …

A New Approach For Measuring The Line-Width Enhancement Factor, Yanguang Yu, Jiangtao Xi, Joe F. Chicharo, Yan Zhao

Faculty of Informatics - Papers (Archive)

The paper presents a new approach for measuring the line-width enhancement factor (LEF) of semiconductor lasers (SLs). LEF can be measured using a technique called optical feedback self-mixing interferometry (OFSMI). However, the existing OFSMI based approaches require that optical feedback factor (denoted as C) associated with the SL systems within a narrow range. The proposed new method is also based on OFSMI principle. The method does not rely on the C factor, and is suitable for the whole moderate optical feedback regime. The associated simulations and the experiments are carried out for verifying the proposed method.