Physical Sciences and Mathematics Commons^™

Mine Boundary Detection Using Partially Ordered Markov Models, Xia Hua, Jennifer Davidson, Noel A. Cressie

Faculty of Informatics - Papers (Archive)

Detection of objects in images in an automated fashion is necessary for many applications, including automated target recognition. In this paper, we present results of an automated boundary detection procedure using a new subclass of Markov random fields (MRFs), called partially ordered Markov models (POMMs). POMMs offer computational advantages over general MRFs. We show how a POMM can model the boundaries in an image. Our algorithm for boundary detection uses a Bayesian approach to build a posterior boundary model that locates edges of objects having a closed loop boundary. We apply our method to images of mines with very good …

Models And Inference For Clustering Of Locations Of Mines And Minelike Objects, Noel A. Cressie, Andrew B. Lawson

Faculty of Informatics - Papers (Archive)

Mines and mine-like objects are distributed throughout an area of interest. Remote sensing of the area form an aircraft yields image data that represent the superposition of electromagnetic emissions from the mines and mine-like objects. In this article we build a hierarchical statistical model for the reconstruction of mien locations given a point pattern of the superposition of mines and mine-like objects. It is shown how inference on the mine locations can be obtained using Markov chain Monte Carlo methods.

On 4-Npaf(1,2w) Sequences, Marc Gysin, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We give an overview on the existence of 4-NPAF (1,2w) sequences. We sketch some construction methods which give new 4-NPAF(1,2w) sequences and new orthogonal designs OD(4n;1,2w).

Weighing Matrices And Their Applications, Christos Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Three major applications of weighing matrices are discussed. New weighing matrices and skew weighing matrices are given for many orders 4t ≤ 100. We resolve the skew-weighing matrix conjecture in the affirmative for 4t ≤ 88.

How To Prevent Cheating In Pinch's Scheme, G. Hossein, J. Pieprzyk, G. Chaundhry, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

A modified protocol is proposed which prevents cheating in the Online multiple secret sharing scheme proposed by Pinch.

Optimal Designs, Supplementary Difference Sets And Multipliers, Christos Koukouvinos, Jennifer Seberry, A. L. Whiteman, Xia Ming-Yuan

Faculty of Informatics - Papers (Archive)

We investigate multipliers of 2 - {v; q², q²; λ} supplementary difference sets where cyclotomy has been used to construct D-optimal designs.

Computer Viruses An Introduction, Jeffrey Horton, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Computer viruses pose a considerable problem for users of personal computers. The recent emergence of macro viruses as a problem of some importance may heighten virus awareness in general. Yet most people have little or no understanding of common anti-virus measures, the varieties of viruses that exist today, and the strategies which they use to accomplish infection and to defeat anti-viruses. It is well-known that the virus problem is most severe for users of IBM PCs and compatibles; however, users of other platforms, such as the Macintosh, should not become complacent - viruses exist for many platforms in varying numbers. …

Application Of Visual Modelling In Image Restoration And Colour Image Processing, Aziz Qureshi, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

This paper describes the application of human visual models in (i) defining a visually uniform colour representation space and (ii) the formulation of visually weighted Kalman filtering for image restoration. The former being useful in colour image quantisation and compression. For (i), the uniformity of chromaticity differences at the ouptut of Frei ’s colour vision model [3] is tested and compensated for by using MacAdam’s uniform chromaticity space. For (ii), the dynamical image model of the Kalman filter is visually weighted using the frequency response of Stockham’s model [l] of human vision.

Shape Vq-Based Adaptive Predictive Lossless Image Coder, Jiazhao Wang, Philip Ogunbona, Golshah Naghdy

Faculty of Informatics - Papers (Archive)

A new shape adaptive predictive lossless image coder is proposed. Three classes of block shapes are delineated with associated “optimum” predctors. Each image is partitioned into sub-blocks that are classified into one of the three classes using vector quantisation. The encoder then employs the predictor corresponding to the class of the block under consideration. Performance evaluation of the proposed coder in comparison with four other lossless coders includmg lossless JPEG indicates its superiority.

On The Step Response Of The Dct, Jim Andrew, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

We show that the discrete cosine transform (DCT) is the best orthogonal transform, in terms of energy packing efficiency, for coding input steps of uniformly distributed random phase. Over sufficiently small block sizes, edges in an image can be modeled as such step inputs. This characteristic of the DCT, coupled with its high energy packing efficiency for highly correlated data, helps explain the impressive performance of the DCT for image compression.

Wavelet-Based Feature-Adaptive Adaptive Resonance Theory Neural Network For Texture Identification, Jiazhao Wang, Golshah Naghdy, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

A new method of texture classification comprising two processing stages, namely a low-level evolutionary feature extraction based on Gabor wavelets and a high-level neural network based pattern recognition, is proposed. The design of these stages is motivated by the processes involved in the human visual system: low-level receptors responsible for early vision processing and the high-level cognition. Gabor wavelets are used as extractors of ‘‘lowlevel’’ features that feed the feature-adaptive adaptive resonance theory (ART) neural network acting as a high-level ‘‘cognitive system.’’ The novelty of the model developed in this paper lies in the use of a self-organizing input layer …

Content-Based Retrieval From Compressed-Image Databases, Philip Ogunbona, P Sangassapaviriya

Faculty of Informatics - Papers (Archive)

There is an enormous amount of multi-media data including images, video, speech, audio and text, distributed among the various computer nodes on the Internet. The extent to which a user wiU be able to derive useful information from these data depends largely on the ease with which required data can be retrieved from the databases. The share volume of the data also poses a storage constraint on the databases; hence these data will need to exist in the compressed form on the databases. In this paper we concentrate on image data and propose a new paradigm in which a compressed …

Edge Image Description Using Fractal Interpolation, P Motallebi, P O. Ogunbona

Faculty of Informatics - Papers (Archive)

Edge images derived from compressed image databases are described using fractal techniques. The proposed method is able to give affine transformation-invariant description suitable for use in a query-by-example database application. Comparison among the proposed method, polynomial interpolation and spline interpolation is given. It is concluded that fractal interpolation can give a compact description of image contours and is able to cope with random perturbation of the coordinates of the contour points by as much as 25 percent.

A Cause Of Chaos, R. Nillsen

Faculty of Informatics - Papers (Archive)

An abstract dynamical system consists of a collection S of points together with a transformation, or function, f which maps points of S into points of S. The points in S stand for all possible states of the system. The transformation is a “process of change” over one time unit, that changes each state x in S into another state f(x). Then we can interpret the equation f(x)=y as meaning that if the system is in state x, over the next time unit it will change into the state y. Alternatively, x is a “cause” of y, or x is …

Chronology Of Holocene Tsunamis On The Southeastern Coast Of Australia, R. W. Young, Edward A. Bryant, David M. Price, S. Y. Dilek, D. J. Wheeler

Faculty of Science - Papers (Archive)

Recent research has revealed much geomorphological evidence for major tsunamis on the southeastern coast of Australia prior to British settlement in 1788. This discovery is important because this tectonically very stable coast was believed to be safe from the hazard of tsunamis because no major tsunami has occurred here in the last 200 years. But high level marine deposits of Holocene age along the coast south of Sydney show that tsunamis ran up to heights of >30 m, and at one site to heights probably >100 m. Developing a chronology for these catastrophic events is of great importance to the …

The Impact Of Tsunami On The Coastline Of Jervis Bay, Southeastern Australia, Edward A. Bryant, R. W. Young, D. M. Price, D. J. Wheeler, M. I. Pease

Faculty of Science - Papers (Archive)

The Jervis Bay area offers а diversity of landforms that do not fit within con¬temporary views of coastal evolution. Field evidence indicates that catastrophic tsunami have had а significant impact on the coast and its hinterland both within and outside the embayment. Runup has overtopped cliffs 80 m above sea level and deposited chevron-shaped ridges to elevations of 130 m on the southern headland. Boulders, up to 6 m in diameter, have been deposited in an imbricated fashion against cliffs, on clifftops, and along shoreline ramps. Bedform features and the size of transported material indicate flow depths up tо 10 …

Late Pleistocene Marine Chronology Of The Gippsland Lakes Region, Australia, Edward A. Bryant, D. M. Price

Faculty of Science - Papers (Archive)

Thermoluminescence dating is used to define the chronology of the coastal barriers of the Gippsland Lakes region, Australia. The area evidences а long history of marine deposition extending back со the Middle Pleistocene. However, the majority of Pleistocene barriers have formed since the Last Interglacial during two phases at 59 to 72 ka and 40 to 48 ka corresponding to interstadials. А third phase, with dates around the Last Glacial, appears со represent rapid shoreward movement of Late Pleistocene sediment from the shelf during the Holocene. Barriers have developed in an en echelon fashion seaward as the region has been …

An Audio Representation For Content Based Retrieval, Kathy Melih, Ruben Gonzalez, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

Despite: the increasing interest in multimedia data retrieval audio data has received little attention. This is due, not to a lack of interest but rather to unique difficulties posed by the medium. In particular existing unstructured audio representations do not easily lend themselves to content based retrieval and especially browsing. This paper aims to address hs oversight by developing an audio representation that provides direct support for browsing and content based retrieval. This support is the result of a structured representation based on psychoacoustic ptincip1.e~in which salient attributes of audio are directly accessible. In addition, the representation is compact thus …

On The Computational Complexity Of The Lbg And Pnn Algorithms, Jamshid Shanbehzadeh, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

This correspondence compares the computational complexity of the pair-wise nearest neighbor (PNN) and Linde–Buzo–Gray (LBG) algorithms by deriving analytical expressions for their computational times. It is shown that for a practical codebook size and training vector sequence, the LBG algorithm is indeed more computationally efficient than the PNN algorithm.

Similarity Measures For Compressed Image Databases, P Sangassapaviriya, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

For image database applications it is desirable that functions such as searching, browsing and partial recall be done without the need to totally decompress the image. This has the advantage of alleviating possible burden and degradation that the network may suffer. Edge images derived from wavelet-compressed images are considered as index that can be queried by example. Zernike moment invariants are used as descriptors for the index edge image and the query sketch image. The descriptions are compared for the purpose of database searching. The query images were allowed to undergo translation, rotation, scaling and some deformation. Simulation results gave …

Index-Compressed Vector Quantisation Based On Index Mapping, Jamshid Shanbehzadeh, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

The authors introduce a novel coding technique which significantly improves the performance of the traditional vector quantisation (VQ) schemes at low bit rates. High interblock correlation in natural images results in a high probability that neighbouring image blocks are mapped to small subsets of the VQ codebook, which contains highly correlated codevectors. If, instead of the whole VQ codebook, a small subset is considered for the purpose of encoding neighbouring blocks, it is possible to improve the performance of traditional VQ schemes significantly. The performance improvement obtained with the new method is about 3dB on average when compared with traditional …

The Contested Domain Of Pastoralism: Landscape, Work And Outsiders In Central Australia , N. J. Gill

Faculty of Science - Papers (Archive)

Extensive cattle grazing has long been the dominant land use in Central Australian rangelands. Today, however, the pastoral landscape is increasingly fractured and contested by indigenous and environmentalist claims on land. Pastoralists in Central Australia are responding to environmentalist claims by reasserting territory. Territory is being constructed with reference to to particular forms of social nature and social space. Identities of insider and outsider have developed. These identities commonly correspond to pastoralists and others, such as conservationists and government, but the place specific nature of pastoralists' environmental knowledge has the potential to render pastoralists as outsiders as well. Moreover, as …

Subcritical, Transcritical And Supercritical Flows Over A Step, Y. Zhang, Song-Ping Zhu

Faculty of Informatics - Papers (Archive)

Free-surface flow over a bottom topography with an asymptotic depth change (a `step') is considered for di erent ranges of Froude numbers varying from subcritical, transcritical, to supercritical. For the subcritical case, a linear model indicates that a train of transient waves propagates upstream and eventually alters the conditions there. This leading-order upstream influence is shown to have profound e ects on higher-order perturbation models as well as on the Froude number which has been conventionally de ned in terms of the steady-state upstream depth. For the transcritical case, a forced Korteweg{de Vries (fKdV) equation is derived, and the numerical …

Discrete-Event Modelling, Simulation And Control Of A Distributed Manipulation Environment, Fazel Naghdy, N. Anjum

Faculty of Informatics - Papers (Archive)

Conventional robotics has proved to be inflexible and non-generic. The concept of Distributed Manipulation Environment (DME) is introduced to overcome some of these shortcomings. This concept proposes a distributed approach to robotics and flexible automation. The work is concerned with modelling, simulation and event based control of DME. The modelling, conducted both at the atomic and the coupled level, is quite generic and provides a framework for static and dynamic behaviour analysis of DME systems. The simulation models serve as a mean of performance evaluation of the system on a computer before the actual implementation in real time. The event-based …

Minimal Critical Set Of A Room Square Of Order 7, Ghulam R. Chaudhry, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

A Room square R of order r is an r x r array each of whose cells may either be empty or contain an unordered pair of objects 0,1,2,...,r, subject to the following conditions:

(i) each of the objects 0,1,2.....r occurs precisely once in each row of R and precisely once in each column of R, and

(ii) every possible unordered pair of objects occurs precisely once in the whole array.

"Albert Leon Whiteman (1915-1995)", S. Golomb, T. Harris, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

The Mathematical Family Tree of Hans Rademacher (with A. Whiteman branch)

On The Smith Normal Form Of Weighing Matrices, Christos Koukouvinos, C. Mitrouli, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

The Smith normal forms (SNF) of weighing matrices are studied. We show that for all orders n ≥ 35 the full spectrum of Smith normal forms (SNF) exists for weighing matrices W(n,9) ie there exists a W(n,9) with SNF 1^1/2(n-s)3^s9^1/2(n-s), for s in a set, which is described, of consecutive integers.

Secure Access To Electronic Strongboxes In Electronic Commerce, Thomas Hardjono, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Two protocols for access to electronic strongbox are described in the context of electronic commerce. The notion of electronic strongboxes is discussed, and the participants of the strongbox system are presented. The two protocols concern two participants of the strongbox systemn namely the Customer who wishes to access a strongbox maintained by a Strongbox Provider. The security aspects of the protocols are then analysed, focusing on possible methods of cheating by the two involved participants.

Factors From Trees, Jacqueline Ramagge, A G. Robertson

Faculty of Informatics - Papers (Archive)

We construct factors of type III,/n for n E N, n > 2, from group actions on homogeneous trees and their boundaries. Our result is a discrete analogue of a result of R.J Spatzier, where the hyperfinite factor of type III1 is constructed from a group action on the boundary of the universal cover of a manifold.