Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- 15A15 (3)
- Complete pivoting (3)
- Gaussian elimination (3)
- Hadamard matrices (3)
- Minors (3)
-
- 05B20 (2)
- AMS Subject Classification: Primary 05B15 (2)
- AMS Subject Classification: Primary 05B20 (2)
- Analysis (2)
- Boundary filters (2)
- D-optimal designs (2)
- Growth (2)
- Multirate signal processing (2)
- Orthogonal designs (2)
- SBIBD (2)
- Subband coding (2)
- Supplementary difference sets (2)
- -sets (1)
- 20B20. (1)
- AMS Subject Classification: 05B20. (1)
- Secondary 62K05. (1)
- 65G05. (1)
- 62K15 (1)
- 65F05 (1)
- 65G05 (1)
- 65G05. (1)
- AMS Subject Classification: 05B20 (1)
- AMS Subject Classification: 65F05 (1)
- Abstract distributions (1)
- Algorithm (1)
Articles 1 - 30 of 32
Full-Text Articles in Entire DC Network
Plant Acoustic Density Profile Model Of Ctfm Ultrasonic Sensing, Phillip J. Mckerrow, N. Harper
Plant Acoustic Density Profile Model Of Ctfm Ultrasonic Sensing, Phillip J. Mckerrow, N. Harper
Faculty of Informatics - Papers (Archive)
Many applications require the sensing of plants. When an ultrasonic sensor insonifies a plant, the resultant echo is the superposition of the echoes from the leaves. As a result, the echo contains information about the geometric structure of the foliage. In this paper, we present a model of sensing that facilitates the extraction of geometric features from the echo for plant classification, recognition and discrimination. We model the echo from a CTFM ultrasonic sensor with the acoustic density profile model. Then, we identify a set of features that represent plant geometric characteristics and use these to perform an inverse transform …
An Optimal Importance Sampling Method For A Transient Markov System, H. Qi, Y. C. Wei, L. Wei
An Optimal Importance Sampling Method For A Transient Markov System, H. Qi, Y. C. Wei, L. Wei
Faculty of Informatics - Papers (Archive)
In this paper an optimal importance sampling (IS) method is derived for a transient markov system. Several propositions are presented. It is showned that the optimal IS method is unique, and it must converge to the standard Monte Carlo (MC) simulation method when the sample path length approaches infinity. Therefore, it is not the size of the state space of the Markov system, but the sample path length, that limits the efficiency of the IS method. Numerical results are presented to support the argument.
New Results On Frame-Proof Codes And Traceability Schemes, R. Safavi-Naini, Yejing Wang
New Results On Frame-Proof Codes And Traceability Schemes, R. Safavi-Naini, Yejing Wang
Faculty of Informatics - Papers (Archive)
In this correspondence we derive lower bounds on the maximum number of codewords in a class of frame-proof codes and traceability schemes, and give constructions for both with more codewords than the best known.
Function Spaces And Multiplier Operators, R. Nillsen, S. Okada
Function Spaces And Multiplier Operators, R. Nillsen, S. Okada
Faculty of Informatics - Papers (Archive)
Let G denote a locally compact Hausdorff abelian group. Then a bounded linear operator T from L^2(G) into L^2(G) is a bounded multiplier operator if, under the Fourier transform on L^2(G ), for each function f in L^2(G), T(f) changes into a bounded function U times the Fourier transform of f. Then U is called the multiplier of T. An unbounded multiplier operator has a similar definition, but its domain is a dense subspace of L^2(G) and the multiplier function need not be bounded. For example, differentiation on the first order Sobolev subspace of L^2(R) is an unbounded multiplier operator …
Assessing Hybrid Classes In A Flexible Learning Environment, M. Lawrence-Slater
Assessing Hybrid Classes In A Flexible Learning Environment, M. Lawrence-Slater
Faculty of Informatics - Papers (Archive)
This paper describes the development of a regime comprising a teaching platform and associated assessment processes. The objective behind these is to enable the equitable assessment of student assignments in hybrid courses. In this paper, the term hybrid refers to courses where the student body comprises both campus-based and off-campus students. Additionally, in either of these groups students may elect to undertake their studies using online resources rather than attend in person. The paper commences with a background discussion on the problem and reasons for seeking alternative approaches to teaching and assessment in hybrid courses. This is followed by a …
The Advantage Of Industrial R&D In The Training Of University Students, J. Fulcher
The Advantage Of Industrial R&D In The Training Of University Students, J. Fulcher
Faculty of Informatics - Papers (Archive)
Experience gained through industrial R&D projects supports the proposition that several benefits flow through to both students and faculty staff beyond that of simply providing associated student project titles. To be more specific, enhancing lecture material with not only specific research findings but also general experience gained from working on such projects are secondary benefits of such university-industry links. Moreover, the reputation and standing of both individual researchers and university research groups are further enhanced by such relationships. This in turn often leads to subsequent industrial R&D projects (and so the cycle continues...).
Scalable Audio Coding Employing Sorted Sinusoidal Parameters, M. Raad, I. Burnett, Alfred Mertins
Scalable Audio Coding Employing Sorted Sinusoidal Parameters, M. Raad, I. Burnett, Alfred Mertins
Faculty of Informatics - Papers (Archive)
This paper describes the use of sorted sinusoidal parameters to produce a fixed rate, scalable, wideband audio coder. The sorting technique relies on the perceptual significance of the sinusoidal parameters. Sinusoidal coding permits the representation of a given signal through the summation of sinusoids. The parameters of the sinusoids (the amplitudes, phases and frequencies) are transmitted to allow signal reconstruction. The sinusoidal parameters are sorted according to energy content and perceptual significance. The most significant parameters are transmitted first, allowing the use of only a small set of the parameters for signal reconstruction. The proposed scheme incurs a low delay …
Boundary Filter Optimization For Segmentation-Based Subband Coding, Alfred Mertins
Boundary Filter Optimization For Segmentation-Based Subband Coding, Alfred Mertins
Faculty of Informatics - Papers (Archive)
This paper presents boundary optimization techniques for the nonexpansive decomposition of arbitrary-length signals with multirate filterbanks. Both biorthogonal and paraunitary filterbanks are considered. The paper shows how matching moments and orthonormality can be imposed as additional conditions during the boundary filter optimization process. It provides direct solutions to the problem of finding good boundary filters for the following cases: (a) biorthogonal boundary filters with exactly matching moments and (b) orthonormal boundary filters with almost matching moments. With the proposed methods, numerical optimization is only needed if orthonormality and exactly matching moments are demanded. The proposed direct solutions are applicable to …
Irrational Rotations Motivate Measurable Sets, R. Nillsen
Irrational Rotations Motivate Measurable Sets, R. Nillsen
Faculty of Informatics - Papers (Archive)
In 1914 Constantin Carathéodory gave his definition of a measurable set, a definition that is crucial in the general theory of integration. This is because a “primitive” notion of area or measure, on a smaller family of sets, can be extended to the larger family of measurable sets, and it is this larger family that has the necessary properties for a natural and complete theory of integration. This more general theory of integration is of enormous practical importance, for it leads to quite broad conditions under which basic operations on integrals are valid. However, Carathéodory’s definition itself remains mysterious, and …
Low Rate Wi Sew Representation Using A Rew-Implicit Pulse Model, J. Lukasiak, I. Burnett
Low Rate Wi Sew Representation Using A Rew-Implicit Pulse Model, J. Lukasiak, I. Burnett
Faculty of Informatics - Papers (Archive)
Reducing the bit rate of waveform interpolation speech coders while maintaining the perceptual quality has been the focus of a great deal of research. This letter proposes a new method of slowly evolving waveform (SEW) quantization specifically targeted at low rate coding. The proposed method uses a pulse model whose parameters are implicitly contained in the quantized rapidly evolving waveform (REW) parameters, thus requiring no bits for transmission. Results indicate no degradation in perceptual speech quality when compared to that of the existing SEW quantization method. This retention of perceptual quality is in spite of a 12% reduction in the …
On Circulant Best Matrices And Their Applications, S. Georgiou, C. Koukouvinos, Jennifer Seberry
On Circulant Best Matrices And Their Applications, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
Call four type 1(1,-1) matrices, x1,x2,x3,x4; of the same group of order m (odd) with the properties (i) (Xi-I)T = -(Xi-I), i=1,2,3, (ii)XT4 = X4 and the diagonal elements are positive, (iii) XiXj = XjXi and (iv) X1XT1 + X2XT2+X3XT3 +X4XT4 = 4mIm, best matrices. We use a computer to give, for the first time, all inequivalent best matrices …
A Security Analysis For Label Switching Routers, M. Al-Ibrahim, M. Savsar, W. Adi
A Security Analysis For Label Switching Routers, M. Al-Ibrahim, M. Savsar, W. Adi
Faculty of Informatics - Papers (Archive)
Label Switching Routers (LSR), such as IP switching of Ipsilon, use separate Virtual Circuits (VC)from different sources even having the same destination. Merging switches, on the other hand, allow multiple VCs of upstream traffic to use a single output VC if having same destination criteria. In this paper, we study IP switching of Ipsilon and identify certain security threats. We found that oscillation between routing and switching as a result of a malicious frequent suspension and releasing of flows is a main security threat that decreases performance of such systems. To stabilize the performance in face of such an attack, …
Temporal Decomposition For Low Rate Wideband Speech Compression, C. H. Ritz, I. Burnett
Temporal Decomposition For Low Rate Wideband Speech Compression, C. H. Ritz, I. Burnett
Faculty of Informatics - Papers (Archive)
An investigation into low bit rate wideband speech coding for applications such as unicast streaming is presented. Wideband spectral parameters are quantised below 1 kbit/s using temporal decomposition (TD) applied to the line spectral frequencies. Quantisation using TD performs significantly better than split vector quantisation at an equivalent bit rate.
Simulating Ultrasonic Sensing With The Lattice Gas Model, Phillip J. Mckerrow, S. M. Zhu, S. New
Simulating Ultrasonic Sensing With The Lattice Gas Model, Phillip J. Mckerrow, S. M. Zhu, S. New
Faculty of Informatics - Papers (Archive)
People have difficulty understanding ultrasonic sensing because they cannot see sound. The purpose of simulation is to overcome this problem by visualizing the scattering of ultrasonic waves off objects. The lattice gas model calculates wave behavior with finite difference equations to produce data suitable for grayscale visualization. This visualization is useful when designing ultrasonic sensing systems for navigating mobile robots. Situations that result in the sensor failing to detect an object can be studied with the simulator.
New D-Optimal Designs Of Order 110, R. J. Fletcher, Jennifer Seberry
New D-Optimal Designs Of Order 110, R. J. Fletcher, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We give two new D-optimal designs of order 110.
Application Of The Discrete Fourier Transform To The Search For Generalised Legendre Pairs And Hadamard Matrices, R. J. Fletcher, M. Gysin, Jennifer Seberry
Application Of The Discrete Fourier Transform To The Search For Generalised Legendre Pairs And Hadamard Matrices, R. J. Fletcher, M. Gysin, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We introduce Legendre sequences and generalised Legendre pairs (GL-pairs). We show how to construct a Hadamard matrix of order 2ℓ + 2 from a GL—pair of length ℓ. We review the known constructions for GL-pairs and use the discrete Fourier transform (DFT) and power spectral density (PSD) to enable an exhaustive search for GL-pairs for lengths ℓ ≤ 45 and partial results for other ℓ.
On Infinite Families Of Sequences With One And Two Valued Autocorrelation And Two Valued Crosscorrelation Function, M. Gysin, Jennifer Seberry
On Infinite Families Of Sequences With One And Two Valued Autocorrelation And Two Valued Crosscorrelation Function, M. Gysin, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We show how to construct infinite families of sequences that have one and two valued autocorrelation and two valued crosscorrelation function. These sequences are obtained via the discrete Fourier transform of integer sequences. The sequences obtained can be complex valued or having entries ε {0, 1, ... , p}, p prime, depending on the construction used.
On Plateaued Functions, Y. Zheng, X. M. Zhang
On Plateaued Functions, Y. Zheng, X. M. Zhang
Faculty of Informatics - Papers (Archive)
The focus of this correspondence is on nonlinear characteristics of cryptographic Boolean functions. First, we introduce the notion of plateaued functions that have many cryptographically desirable properties. Second, we establish a sequence of strengthened inequalities on some of the most important nonlinearity criteria, including nonlinearity, avalanche, and correlation immunity, and prove that critical cases of the inequalities coincide with characterizations of plateaued functions.We then proceed to prove that plateaued functions include as a proper subset all partially bent functions that were introduced earlier by Claude Carlet. This solves an interesting problem that arises naturally from previously known results on partially …
On Ternary Complementary Pairs, M. Gysin, Jennifer Seberry
On Ternary Complementary Pairs, M. Gysin, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
Let A = {a0, ... aℓ-1 }, B = {b0, . . . , bℓ-1 } be two finite sequences of length ℓ. Their nonperiodic autocorrelation function NA,B (s) is defined as: NA,B(s) = ∑aiai+1 + ∑b1bi+1, s = 0,…,ℓ-1 where x* is the complex conjugate of x. If NA,B (s) = 0 for s = 1, ... , ℓ - 1 then A, B is called a complementary pair. If, furthermore, ai, bi ε {-1,1}, i = 0,...,ℓ-1 , or, ai, bi ε {-1,0,1}, i = 0, ... , ℓ-1, then A, B is called a binary complementary pair …
Boundary Filters For Size-Limited Paraunitary Filter Banks With Maximum Coding Gain And Ideal Dc Behavior, Alfred Mertins
Boundary Filters For Size-Limited Paraunitary Filter Banks With Maximum Coding Gain And Ideal Dc Behavior, Alfred Mertins
Faculty of Informatics - Papers (Archive)
This paper presents boundary optimization techniques for the processing of arbitrary-length signals with paraunitary multirate filter banks. The boundary filters are designed to maximize the coding gain while providing an ideal DC behavior where all filters except the low-pass filters have zero mean. Moreover, solutions are presented that have similar frequency responses as the original subband filters. The proposed methods give direct solutions to the problem of finding the optimal boundary filters with maximum coding gain and do not require numerical optimization. Thus, they are even applicable to systems with a large number of subbands and/or very long filter impulse …
Equitability In Retroactive Data Confiscation Versus Proactive Key Escrow, Y. Desmedt, M. Burmester, Jennifer Seberry
Equitability In Retroactive Data Confiscation Versus Proactive Key Escrow, Y. Desmedt, M. Burmester, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
The British Regulations of Investigatory Powers (RIP) Act 2000 is one of the first modern bills for mandatory disclosure of protected data in a democratic country. In this paper we compare this bill from a technical point of view with the US key escrow proposal (EES) and its variants and then, more generally we compare the merits of key confiscation vs key escrow. A major problem with key escrow is that once a private key is recovered it can be used to decipher ciphertexts which were sent well before a war-rant was issued (or after its expiration). Several alternative key …
Development And Performance Analysis Of A Single Axis Linear Motor, Jeffrey W. Moscrop, Christopher David Cook, Fazel Naghdy
Development And Performance Analysis Of A Single Axis Linear Motor, Jeffrey W. Moscrop, Christopher David Cook, Fazel Naghdy
Faculty of Informatics - Papers (Archive)
The ever-increasing demands placed on industrial machine tool manufacturers, for greater speeds and accuracies, are beginning to exceed the capabilities of current machine tool technologies. However, the ongoing revolution in computer, sensor and actuator technologies has introduced the potential of economically meeting these higher demands through new approaches in machine tool design. One actuator technology currently influencing high precision industrial automation is the linear motor. This paper details the development of a single axis linear motor test-bed, replicating one axis of a laser cutting machine tool. Through analysis of system stiffness and torque disturbances, the performance of the linear motor …
Values Of Minors Of (1,-1) Incidence Matrices Of Sbibds And Their Application To The Growth Problem, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Values Of Minors Of (1,-1) Incidence Matrices Of Sbibds And Their Application To The Growth Problem, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We obtain explicit formulae for the values of the v - j minors, j = 0,1,2 of (1, -1) incidence matrices of SBIBD(v,k,λ). This allows us to obtain explicit information on the growth problem for families of matrices with moderate growth. An open problem remians to establish whether the (1, -1) CP incidence matrices of SBIBD(v,k,λ), can have growth greater than V for families other than Hadamard families.
Signal Analysis Using A Multiresolution Form Of The Singular Value Decomposition, Ramakrishna Kakarala, Philip Ogunbona
Signal Analysis Using A Multiresolution Form Of The Singular Value Decomposition, Ramakrishna Kakarala, Philip Ogunbona
Faculty of Informatics - Papers (Archive)
This paper proposes a multiresolution form of the singular value decomposition (SVD) and shows how it may be used for signal analysis and approximation. It is well-known that the SVD has optimal decorrelation and subrank approximation properties. The multiresolution form of SVD proposed here retains those properties, and moreover, has linear computational complexity. By using the multiresolution SVD, the following important characteristics of a signal may be measured, at each of several levels of resolution: isotropy, sphericity of principal components, self-similarity under scaling, and resolution of mean-squared error into meaningful components. Theoretical calculations are provided for simple statistical models to …
Short Amicable Sets And Kharaghani Type Orthogonal Designs, C. Koukouvinos, Jennifer Seberry
Short Amicable Sets And Kharaghani Type Orthogonal Designs, C. Koukouvinos, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
Short amicable sets were introduced recently and have many applications. The construction of short amicable sets had lead to the construction of many orthogonal designs, weighing matrices and Hadamard matrices. In this paper we give some constructions for short amicable sets as well as some multiplication theorems. We also present a table of the short amicable sets known to exist and we construct some infinite families of short amicable sets and orthogonal designs.
An Algorithm To Find Formulae And Values Of Minors For Hadamard Matrices, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
An Algorithm To Find Formulae And Values Of Minors For Hadamard Matrices, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We give an algorithm to obtain formulae and values for minors of Hadamard matrices. One step in our algorithm allows the (n – j) x (n – j) minors of an Hadamard matrix to be given in terms of the minors of a 2j-1 x 2j-1 matrix. In particular we illustrate our algorithm by finding explicitly all the (n – 4) x (n – 4) minors of an Hadamard matrix.
Values Of Minors Of An Infinite Family Of D-Optimal Designs And Their Application To The Growth Problem, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Values Of Minors Of An Infinite Family Of D-Optimal Designs And Their Application To The Growth Problem, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We obtain explicit formulae for the values of the 2v — j minors, j = 0, 1, 2 of D-optimal designs of order 2v = x2 + y2, v odd, where the design is constructed using two circulant or type 1 incidence matrices of either two SBIBD(2s2 + 2s + 1, s2, s2-s/2) or 2 — {2s2 + 2s + 1; s2, s2; s(s–1)} sds. This allows us to obtain information on the growth problem for families of matrices with moderate growth. Some of our theoretical formulae imply growth greater than 2(2s2 + 2s + 1) but experimentation has not …
A New Algorithm For Computer Searches For Orthogonal Designs, S. Georgiou, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
A New Algorithm For Computer Searches For Orthogonal Designs, S. Georgiou, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We present a new algorithm for computer searches for orthogonal designs. Then we use this algorithm to find new sets of sequences with entries from {0, ±a, ±b, ±c, ±d} on the commuting variables a, b, c, d with zero autocorrelation function.
E-Business: Revolution, Evolution, Or Hype?, T. Coltman, T. M. Devinney, A. Latukefu, D. F. Midgley
E-Business: Revolution, Evolution, Or Hype?, T. Coltman, T. M. Devinney, A. Latukefu, D. F. Midgley
Faculty of Informatics - Papers (Archive)
As the Internet continues to grow in size and capability, many firms are implementing Web-based applications and Internet-derived economic change continues to occur. If this change is revolutionary, now or in the near future, then many managers will be required to rethink their firm strategies and managerial responses in a profound way. On the other hand, if the change is simply evolutionary, it will apply more to some firms than to others, and pre-Internet strategies and managerial responses will still be appropriate in many circumstances. While it is premature to categorize e-business as revolutionary, e-business is not a silver bullet, …
On The Complete Pivoting Conjecture For Hadamard Matrices Of Small Orders, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
On The Complete Pivoting Conjecture For Hadamard Matrices Of Small Orders, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
In this paper we study explicitly the pivot structure of Hadamard matrices of small orders 16, 20 and 32. An algorithm computing the (n — j) x (n — j) minors of Hadamard matrices is presented and its implementation for n = 12 is described. Analytical tables summarizing the pivot patterns attained are given.