Physical Sciences and Mathematics Commons^™

Exploration Of The Internet Controlled 'Rent-A-Factory' Concept, Laurence Bate, Christopher David Cook

Faculty of Informatics - Papers (Archive)

There are several robots and other devices which can now be controlled over the Internet. It is possible that an expansion of this concept ultimately leading to an Internet controlled factory could assist Australia overcome the 'tyranny' both of distance and of small production volumes. This paper discusses initial work being performed to investigate the relevance and practicality of the Internet for remote factory operations. A review of current Internet controlled equipment is presented. New experimental work involving the development of a web based graphical interface enabling clear observation and control of an Adept-One robot over the World Wide Web …

Behavioural Modelling Of High Temperature Superconducting Wires And Coils For Power Engineering Applications, Thomas Hardjono, Christopher David Cook, Sarath Perera

Faculty of Informatics - Papers (Archive)

Many aspects of the behaviour of high temperature superconducting (HTS) wires are well understood for dc applications. However, models of HTS suitable for use in circuit analysis by power engineers designing HTS applications are not readily available. This paper describes the initial development of suitable models for HTS wire. The V-I characteristics for wires carrying dc transport current can be empirically determined using a power law V=kIn. Experimentally measured V-I characteristics are fitted using the above power law. This enables the simulation of the behaviour of Bi-2223/Ag wire using the well-known circuit simulator PSpice. Other factors affecting the dc critical …

An Examination Of The Efficiency Of Australian Crop Variety Evaluation Programmes, Brian R. Cullis, A B. Smith, C Hunt, Arthur R. Gilmour

Faculty of Informatics - Papers (Archive)

In this paper we present the analysis of yield data from a broad cross-section of crop variety evaluation programmes (CVEP) conducted in Australia. The main sources of variety by environment interaction are ` non-static ' interactions, namely those linked to seasonal influences. These contributed an average of 41.3% of the total variance. In contrast the static component accounts for only 5.3% of the total.

We develop methods for determining the relative accuracy of CVEP based on selection of newly promoted entries. The accuracy of the current testing regimes for the Australian CVEP under study is determined. The accuracy of alternative …

Secure Compression Using Adaptive Huffman Coding, C. Kailasananathan, Reihaneh Safavi-Naini, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

Recent developments in the Internet and Web based technologies require faster communication of multimedia data in a secure form. Standard compression algorithms such arithmetic coding schemes, and propose methods of protecting against these attacks. In the next section we review DHC, and in Section 3 describe DHC encryption scheme and examine possible attacks. In Section 4, we propose an encryption scheme that protects against the attacks and in Section 5 give the results of our experiments. Section 6, concludes the paper. as JPEG and MPEG use an entropy coding stage. By incorporating security in this stage it it possible to …

Securing Wavelet Compression With Random Permutations, Takeyuki Uehara, Reihaneh Safavi-Naini, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

Wavelet compression for digital images achieves very high compression with reasonably high image quality and so is widely used in various applications. Adding security to compression algorithms has been proposed in a number of compression systems with the aim reducing the overall cost of compression and encryption. In this paper we propose a combined compression and encryption system based on wavelet transform and examine its security. Our results show that with a relatively small added cost varying degrees of security can be obtained while maintaining the performance of the compression system.

Necessary And Sufficient Conditions For Two Variable Orthogonal Designs In Order 44: Addendum, S. Georgiou, C. Koukouvinos, M. Mitrouli, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

In our recent paper Necessary and sufficient conditions for some two variable orthogonal designs in order 44, Koukouvinos, Mitrouli and Seberry leave 7 cases unresolved. Using a new algorithm given in our paper A new algorithm for computer searches for orthogonal designs by the present four authors we are able to finally resolve all these cases. This note records that the necessary conditions for the existence of two variable designs constructed using four circulant matrices are sufficient. In particular of 484 potential cases 404 cases have been found, 68 cases do not exist and 12 cases cannot be constructed using …

Strongbox Secured Secret Sharing Schemes, Jennifer Seberry, A. Penfold Street

Faculty of Informatics - Papers (Archive)

We present one way in which combinatorial designs can be used to give conditionally perfect secret sharing schemes. Schemes formed in this way have the advantage over classical secret sharing schemes of being easily adapted for use as compartmentalized or hierarchical access structures. We study the problem of completion of structures, given partial information, to obtain measures of how closely the behaviour of the secret sharing schemes approaches to ideal behaviour in practice. It may happen that part of a combinatorial design can never be reconstructed from a subset of a minimal defining set. That is, to find the blocks …

Identification Of Bad Signatures In Batches, J. Pastuszak, D. Michalek, J. Pieprzyk, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

The paper addresses the problem of bad signature identification in batch verification of digital signatures. The number of generic tests necessary to identify all bad signatures in a batch instance, is used to measure the efficiency of verifiers. The divide-and-conquer verifier DCVα(x,n) is defined. The verifier identifies all bad signatures in a batch instance x of the length n by repeatedly splitting the input into α sub-instances. Its properties are investigated. In particular, probability distributions for the number of generic tests necessary to identify one, two and three bad signatures, are derived. The average numbers of GT tests necessary to …

Homogeneous Bent Functions, C. Qu, Jennifer Seberry, J. Pieprzyk

Faculty of Informatics - Papers (Archive)

This paper discusses homogeneous bent functions. The space of homogeneous functions of degree three in six boolean variables was exhaustively searched and thirty bent functions were found. These are found to occur in a single orbit under the action of relabelling of the variables. The homogeneous bent functions identified exhibit interesting combinatorial structures and are, to the best of our knowledge, the first examples of bent functions without quadratic terms. A construction for other homogeneous bent functions of degree three in larger spaces is also given.

The Method Of Generalised Conditional Symmetries And Its Various Implementations, J. M. Goard

Faculty of Informatics - Papers (Archive)

We relate Kaptsov's method of B-determining equations for nding invariant solutions of PDEs to the nonclassical method and to the method of generalised conditional symmetries. An extension of Kaptsov's method is then used to nd new solutions of degenerate diusion equations.

A Third-Order Boussinesq Model Applied To Nonlinear Evolution Of Shallow-Water Waves, Y. L. Zhang, Song-Ping Zhu

Faculty of Informatics - Papers (Archive)

The conventional Boussinesq model is extended to the third order in dispersion and nonlinearity. The new equations are shown to possess better linear dispersion characteristics. For the evolution of periodic waves over a constant depth, the computed wave envelops are spatially aperiodic and skew. The model is then applied to the study of wave focusing by a topographical lens and the results are compared with Whalin's (1971) experimental data as well as some previous results from the conventional Boussinesq model. Encouragingly, improved agreement with Whalin's experimental data is found.

Result Of Ac Loss Tests On Twisted And Untwisted Htsc Tape Exposed To An External Field, Tri Hardono, Christopher David Cook, Frank Darmann

Faculty of Informatics - Papers (Archive)

This paper presents the results of magnetic loss tests on twisted and untwisted 37 multifilament tapes exposed to an alternating field at power frequencies. The losses are measured using calorimetric methods, which are capable of measuring losses in short tapes with the accuracy of several microwatts per centimeter of tape. The losses of the tape due to the longitudinal field of the untwisted tape agree well with theoretical calculations. The measurement results on the twisted filament tape, with 50-mm twist pitch, show that the losses are slightly lower than that in the untwisted tape. This is due to the reduction …

Growth In Gaussian Elimination For Weighing Matrices, W (N, N — 1), C. Koukouvinos, M. Mitrouli, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We consider the values for large minors of a skew-Hadamard matrix or conference matrix W of order n and find maximum n x n minor equals to (n — 1)n/2, maximum (n — 1) x (n — 1) minor equals to (n–1)n/2-1 maximum (n — 2) x (n — 2) minor equals to 2(n — 1) n/2–2, and maximum (n — 3) x (n — 3) minor equals to 4(n — 1)n/2-3. This leads us to conjecture that the growth factor for Gaussian elimination of completely pivoted skew-Hadamard or conference matrices and indeed any completely pivoted weighing matrix of order …

New Orthogonal Designs And Sequences With Two And Three Variables In Order 28, C. Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We give new sets of sequences with entries from {0, ±a, ±b, ±c} on the commuting variables a, b, c and zero autocorrelation function. Then we use these sequences to construct some new orthogonal de-signs. We show the necessary conditions for the existence of an OD(28; s1, s2, s3) plus the condition that (s1, s2, s3) ≠ (1,5,20) are sufficient conditions for the existence of an OD(28; s1, s2, s3). We also show the necessary conditions for the existence of an OD(28; s1, s2, s3) constructed using four circulant matrices are sufficient conditions for the existence of 4 — NPAF(s1, …

Influence Of Entries In Critical Sets Of Room Squares, Ghulam Chaudhry, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We consider structures which have rules for completion such as balanced incomplete block designs, Latin squares, Rooms squares, F-squares, Youden squares, regular graphs, colourings, finite geometries and difference sets. In particular we are concerned with the problem of unique completion of structures given partial information. If the partial structure can be uniquely completed then this partial structure together with the rules contains the same information as the final structure. In this paper, we study the information inherent in partial Room squares, where it is not possible to uniquely complete the square. We study the influence and power of parts of …

An Almost Optimal Fail-Stop Signature Scheme, Willy Susilo, R. Safavi-Naini, M. Gysin, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Security of ordinary digital signature schemes relies on a computational assumption. Fail-stop signature schemes provide security for a sender against a forger with unlimited computational power by enabling the sender to provide a proof of forger, if it occurs. In this paper, we give an efficient fail-stop signature scheme that uses two hard problems, discrete logarithm and factorisation , as the basis of receiver's security. We show that the scheme has provable security against adaptively chosen message attack and is the most efficient scheme with respect to the ratio of the message length to the signature length. The scheme provides …

Long-Lead Prediction Of Pacific Ssts Via Bayesian Dynamic Modeling, L M. Berliner, Christopher K. Wikle, Noel A. Cressie

Faculty of Informatics - Papers (Archive)

Tropical Pacific sea surface temperatures (SSTs) and the accompanying El Nino-Southern Oscillation phenomenon are recognized as significant components of climate behavior. The atmospheric and oceanic processes involved display highly complicated variability over both space and time. Researchers have applied both physically derived modeling and statistical approaches to develop long-lead predictions of tropical Pacific SSTs. The comparative successes of these two approaches are a subject of substantial inquiry and some controversy. Presented in this article is a new procedure for long-lead forecasting of tropical Pacific SST fields that expresses qualitative aspects of scientific paradigms for SST dynamics in a statistical manner. …

"For It Is The Number Of A Man", M. G. Michael

Faculty of Informatics - Papers (Archive)

No abstract provided.

Back Circulant Latin Squares And The Influence Of A Set, L. F. Fitina, Jennifer Seberry, G. R. Chaudhry

Faculty of Informatics - Papers (Archive)

We define the notions of nest and influence of a subset of a critical set of a back circulant latin square, and study their properties. We also show that a secret sharing scheme based on a critical set of a latin square is both compartmentalised, and hierachical.

When The Necessary Conditions Are Not Sufficient: Sequences With Zero Autocorrelation Function, J. Horton, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Recently K. T. Arasu (personal communication) and Yoseph Strassler, in his PhD thesis, The Classification of Circulant Weighing Matrices of Weight 9, Bar-Ilan University, Ramat-Gan, 1997, have intensively studied circulant weighing matrices, or single sequences, with weight 9. They show many cases are non-existent. Here we give details of a search for two sequences with zero periodic autocorrelation and types (1,9), (1,16) and (4,9). We find some new cases but also many cases where the known necessary conditions are not sufficient. We instance a number of occasions when the known necessary conditions are not sufficient for the existence of weighing …

Soliton Evolution And Radiation Loss For The Sine-Gordon Equation , N. F. Smyth, Annette L. Worthy

Faculty of Informatics - Papers (Archive)

An approximate method for describing the evolution of solitonlike initial conditions to solitons for the sine-Gordon equation is developed. This method is based on using a solitonlike pulse with variable parameters in an averaged Lagrangian for the sine-Gordon equation. This averaged Lagrangian is then used to determine ordinary differential equations governing the evolution of the pulse parameters. The pulse evolves to a steady soliton by shedding dispersive radiation. The effect of this radiation is determined by examining the linearized sine-Gordon equation and loss terms are added to the variational equations derived from the averaged Lagrangian by using the momentum and …

The Genre Of The Apocalypse: What Are They Saying Now?, M. G. Michael

Faculty of Informatics - Papers (Archive)

No abstract provided.

Observations On 666 In The Old Testament, M. G. Michael

Faculty of Informatics - Papers (Archive)

No abstract provided.

On F-Squares And Their Critical Sets, L. F. Fitina, Jennifer Seberry, D. Sarvate

Faculty of Informatics - Papers (Archive)

We define the notion of critical set of an F-square, following the definition of critical set in latin squares, and then give critical sets for certain classes of F-squares. We also generalise certain results obtained for critical sets of latin squares, and look at minimal such sets. We show that critical sets of F-squares need to be studied as well as critical sets for latin squares as the techniques used differ considerably. We obtain theorems for the sizes of critical sets of types F(n; 1,n — 1), F(n;1, 1, n — 2), and F(n; 2, 2, ... , 2).

Asymptotic Solitons Of The Extended Korteweg–De Vries Equation, Timothy R. Marchant

Faculty of Informatics - Papers (Archive)

The interaction of two higher-order solitary waves, governed by the extended Korteweg–de Vries (KdV) equation, is examined. A nonlocal transformation is used on the extended KdV equation to asymptotically transform it to the KdV equation. The transformation is used to derive the higher-order two-soliton collision and it is found that the interaction is asymptotically elastic. Moreover, the higher-order corrections to the phase shifts suffered by the solitary waves during the collision are found. Comparison is made with a previous result, which indicated that, except for a special case, the interaction of higher-order KdV solitary waves is inelastic, with a coupling, …

New Weighing Matrices And Orthogonal Designs Constructed Using Two Sequences With Zero Autocorrelation Function - A Review, C. Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

The book, Orthogonal Designs: Quadratic Forms and Hadamard Matrices, Marcel Dekker, New York-Basel, 1979, by A. V. Geramita and Jennifer Seberry, has now been out of print for almost two decades. Many of the results on weighing matrices presented therein have been greatly improved. Here we review the theory, restate some results which are no longer available and expand on the existence of many new weighing matrices and orthogonal designs of order 2n where n is odd. We give a number of new constructions for orthogonal designs. Then using number theory, linear algebra and computer searches we find new weighing …

Crypto Topics And Applications Ii, Jennifer Seberry, C. Charnes, J. Pieprzyk, R. Safavi-Naini

Faculty of Informatics - Papers (Archive)

In this chapter we continue our exposition of the crypto topics which was begun in the previous chapter. This chapter covers: Secret Sharing, Threshold Cryptography, Signature Schemes, and finally Quantum Key Distribution and Quantum Cryptography. As in the previous chapter, we have focused only on the essentials of each topic. We have included in the bibliography sufficient items which can be consulted for further details.

Crypto Topics And Applications I, Jennifer Seberry, C. Charnes, J. Pieprzyk, R. Safavi-Naini

Faculty of Informatics - Papers (Archive)

In this chapter we discuss four related areas of cryptology, namely: Authentication, Hashing, Message Authentication Codes (MACs), and Digital Signatures. These topics represent currently active and growing research topics in cryptology. Due to space limitations, we concentrate only on the essential aspects of each topic. The bibliography is intended to supplement our survey. We have included sufficiently many items to provide the interested reader with an overall view of the current state of knowledge in the above areas.

Exact Neumann Boundary Controllability For Problems Of Transmission Of The Wave Equation, W. Liu, G. H. Williams

Faculty of Informatics - Papers (Archive)

Using the Hilbert Uniqueness Method, we study the problem of exact controllability in Neumann boundary conditions for problems of transmission of the wave equation. We prove that this system is exactly controllable for all initial states in L2(Omega) x (H1(Omaga))'.

On Circulant Weighing Matrices, K. T . Arasu, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Algebraic techniques are employed to obtain necessary conditions for the existence of certain circulant weighing matrices. As an application we rule out the existence of many circulant weighing matrices. We study orders n = s2 + s + 1, for 10 less than or equal to s less than or equal to 25. These orders correspond to the number of points in a projective plane of order s.