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- Audio coding (3)
- Data compression (3)
- Levels (3)
- Sequences (3)
- Systems (3)
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- Amicable sets (2)
- Codes (2)
- Construction (2)
- Current (2)
- Distribution (2)
- Grinding (2)
- Hadamard matrices (2)
- Harmonic (2)
- Mv (2)
- Orthogonal designs (2)
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- Spatial (2)
- Speech coding (2)
- Statistics (2)
- Study (2)
- Testing (2)
- Transform coding (2)
- Trees (mathematics) (2)
- quantisation (signal) (1)
- trees (mathematics) (1)
- AMS Classification 05B05. (1)
- AMS Subject Classification: 65F05 65G05 20B20. (1)
- Hall polynomial. (1)
- AMS Subject Classification: 05820. (1)
- High non-linearity. (1)
Articles 31 - 60 of 86
Full-Text Articles in Physical Sciences and Mathematics
Low Bit Rate Wideband Wi Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak
Low Bit Rate Wideband Wi Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak
Faculty of Informatics - Papers (Archive)
This paper investigates waveform interpolation (WI) applied low bit rate wideband speech coding. An analysis of the evolutionary behaviour of wideband characteristic waveforms (CWs) shows that direct application of the classical WI algorithm may not be appropriate for wideband speech. We propose a modification whereby CW quantisation is performed using classical WI decomposition for the low frequency region and noise modelling for the high frequency region. Wideband WI coders incorporating this modification and operating at 4 kbps and 6 kbps are described. Subjective testing of these coders shows that WI is a promising approach to low bit rate wideband speech …
Multi-Rate And Multi-Resolution Scalable To Lossless Audio Compression Using Pspiht, M. Raad, I. Burnett, Alfred Mertins
Multi-Rate And Multi-Resolution Scalable To Lossless Audio Compression Using Pspiht, M. Raad, I. Burnett, Alfred Mertins
Faculty of Informatics - Papers (Archive)
This paper presents a scalable to lossless compression scheme that allows scalability in terms of sampling rate as well as quantization resolution. The scheme presented is perceptually scalable and it also allows lossless compression. The scheme produces smooth objective scalability, in terms of SNR, until lossless compression is achieved. The scheme is built around the perceptual SPIHT algorithm, which is a modification of the SPIHT algorithm. Objective and subjective results are given that show perceptual as well as objective scalability. The subjective results given also show that the proposed scheme performs comparably with the MPEG-4 AAC coder at 16, 32 …
An Extended Acdc Algorithm For The Blind Estimation Of Convolutive Mixing Systems, Alfred Mertins, I. Russell
An Extended Acdc Algorithm For The Blind Estimation Of Convolutive Mixing Systems, Alfred Mertins, I. Russell
Faculty of Informatics - Papers (Archive)
This paper presents an extension of the ACDC algorithm introduced by Yeredor for the instantaneous mixing problem to the more general convolutive mixing problem with non-white sources. Further assumptions made on the source signals are their mutual statistical independence, nonstationarity and smoothness of their power spectra. The algorithm iterates the estimation of the mixing system (AC step) and the source statistics (DC step) until convergence is achieved. The proposed algorithm operates in the frequency domain, but unlike most frequency domain algorithms, it carries out some of the operations jointly for all frequencies. This allows us to overcome frequency dependent permutation …
The Maximal Determinant And Subdeterminants Of ±1 Matrices, Jennifer Seberry, Tianbing Xia, C. Koukouvinos, M. Mitrouli
The Maximal Determinant And Subdeterminants Of ±1 Matrices, Jennifer Seberry, Tianbing Xia, C. Koukouvinos, M. Mitrouli
Faculty of Informatics - Papers (Archive)
In this paper we study the maximal absolute values of determinants and subdeterminants of ±1 matrices, especially Hadamard matrices. It is conjectured that the determinants of ±1 matrices of order n can have only the values k • p, where p is specified from an appropriate procedure. This conjecture is verified for small values of n. The question of what principal minors can occur in a completely pivoted ±1 matrix is also studied. An algorithm to compute the (n — j) x (n — j), j = 1, 2, ... minors of Hadamard matrices of order n is presented, and …
Some Results On Self-Orthogonal And Self-Dual Codes, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Some Results On Self-Orthogonal And Self-Dual Codes, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We use generator matrices G satisfying GGT = aI+bJ over Zk to obtain linear self-orthogonal and self-dual codes. We give a new family of linear self-orthogonal codes over GF(3) and Z4 and a new family of linear self-dual codes over GF(3).
Generalized Bhaskar Rao Designs With Block Size 4 Signed Over Elementary Abelian Groups , G. Ge, M. Greig, Jennifer Seberry
Generalized Bhaskar Rao Designs With Block Size 4 Signed Over Elementary Abelian Groups , G. Ge, M. Greig, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
de Launey and Seberry have looked at the existence of Generalized Bhaskar Rao designs with block size 4 signed over elementary Abelian groups and shown that the necessary conditions for the existence of a (v, 4, λ; EA(g)) GBRD are sufficient for λ > g with 70 possible exceptions. This article extends that work by reducing those possible exceptions to just a (9,4,18h; EA(9h)) GBRD, where gcd(6, h) = 1, and shows that for λ = g the necessary conditions are sufficient for v > 46.
Performance Of Mpeg-7 Low Level Audio Descriptors With Compressed Data, Jason Lukasiak, David A. Stirling, N. Harders, S. Perrow
Performance Of Mpeg-7 Low Level Audio Descriptors With Compressed Data, Jason Lukasiak, David A. Stirling, N. Harders, S. Perrow
Faculty of Informatics - Papers (Archive)
This paper presents a detailed analysis of lossy compression effects on a set of the MPEG-7 low-level audio descriptors. The analysis results show that lossy compression has a detrimental effect on the integrity of practical search and retrieval schemes that utilize the low level audio descriptors. Methods are then proposed to reduce the detrimental effects of compression in searching schemes. These proposed methods include multi-frame searching and machine learning derived prediction. The proposed mechanisms greatly reduce the effect of compression on the set of MPEG-7 descriptors; however, future scope is identified to develop new audio descriptors that account for compression …
Scalable To Lossless Audio Compression Based On Perceptual Set Partitioning In Hierarchical Trees (Pspiht), M. Raad, Alfred Mertins, I. Burnett
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)
This paper proposes a technique for scalable and also provides for lossless compression. It reduces smooth objective scalability, in terms of SegSNR, from lossy to lossless compression. The proposal is built around the perceptual SPIHT algorithm, which is a modification of the SPIHT algorithm and is introduced in this paper. Both objective and subjective results are reported and demonstrate 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.
Construction Of Highly Non-Linear Cubic Homogeneous Boolean Functions On Gf2n+L (2), Jing Wu, Tianbing Xia, Jennifer Seberry
Construction Of Highly Non-Linear Cubic Homogeneous Boolean Functions On Gf2n+L (2), Jing Wu, Tianbing Xia, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
The work studies highly nonlinear Boolean functions in GF2n+1(2), i.e. for the dimensions where bent functions do not exist. We prove that for every n > 2 there exist homogeneous Boolean functions on GF(2)2n+1 with non-linearity greater than or equal to 22n — 2n and without linear structures.
On Using Fast Exponentiation Algorithm In Pdas (Or: How Secure Is The Discrete Logarithm Problem Assumption In Pdas?) , Willy Susilo, Jianyong Huang, Jennifer Seberry
On Using Fast Exponentiation Algorithm In Pdas (Or: How Secure Is The Discrete Logarithm Problem Assumption In Pdas?) , Willy Susilo, Jianyong Huang, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
Personal Digital Assistants (PDAs) are the miniature of normal size PCs, with a very limited computational power. In this paper, we investigate the security of PDAs when they are used to perform some cryptographic applications. In our context, we investigate the computation y = g' (mod p), for a prime p, which is believed to be secure in the sense of the Discrete Logarithm Problem (DLP) assumption. To be more precise, knowing only p, g and y, it is hard to derive x. We note that this computation is the most important operation in most cryptographic algorithms. However, due to …
An Activity Theory Framework For Computer Interface Design, E. Gould, I. Verenikina
An Activity Theory Framework For Computer Interface Design, E. Gould, I. Verenikina
Faculty of Informatics - Papers (Archive)
Computer interface design has the primary purpose of assisting information technology users in their professional activities. In order to accomplish this, users need to be able to work 'through the interface' to complete the tasks which achieve the goals associated with an activity. Although this is the conceptual province of psychology, very little use has been made of psychology in practical interface design. The attempts that have been made appear to have suffered from a lack of connection to real life problems which has been attributed to their foundations in the information processing structure of cognitive psychology. We elaborate an …
Weighing Matrices And Self-Orthogonal Quaternary Codes, C. Charnes, Jennifer Seberry
Weighing Matrices And Self-Orthogonal Quaternary Codes, C. Charnes, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We consider families of linear self-orthogonal and self-dual codes over the ring Z4 which are generated by weighing matrices W (n, k) k ≡ 0 (mod 4), whose entries are interpreted as elements of the ring Z4. We obtain binary formally self-dual codes of minimal Hamming distance 4 by applying the Gray map to the quaternary codes generated by W (n, 4).
On Full Orthogonal Designs In Order 72, S. Georgiou, C. Koukouvinos, Jennifer Seberry
On Full Orthogonal Designs In Order 72, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We find new full orthogonal designs in order 72 and show that of 2700 possible OD(72; s1, s2, s3, 72—s1—s2—s3) 335 are known, of 432 possible OD(72; s1, s2, 72—si—s2) 308 are known. All possible OD(72; s1, 72 — s1) are known.
Further Observations On The Structure Of The Aes Algorithm, B. Song, Jennifer Seberry
Further Observations On The Structure Of The Aes Algorithm, B. Song, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
Abstract. We present our further observations on the structure of the AES algorithm relating to the cyclic properties of the functions used in this cipher. We note that the maximal period of the linear layer of the AES algorithm is short, as previously observed by S. Murphy and M.J.B. Robshaw. However, we also note that when the non-linear and the linear layer are combined, the maximal period is dramatically increased not to allow algebraic clues for its cryptanalysis. At the end of this paper we describe the impact of our observations on the security of the AES algorithm. We conclude …
Regular Hadamard Matrices, Maximum Excess And Sbibd, Tianbing Xia, M. Xia, Jennifer Seberry
Regular Hadamard Matrices, Maximum Excess And Sbibd, Tianbing Xia, M. Xia, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
When k = q1, q2, q1q2, q1q4, q2q3N, q3q4N, q1, q2 and q3 are prime power, where q1 ≡ 1 (mod 4), q2 ≡ 3 (mod 8), q3 ≡ 5 (mod 8), q4 = 7 or 23, N = 2a3bt2, a, b = 0 or 1, t ≠ 0 is an arbitrary integer, we prove that there exist regular Hadamard matrices of order 4k2, and also there exist SBIBD(4k2, 2k2 + k, k2 + k). We find new SBIBD(4k2, 2k2 + k, k2 + k) for 233 values of k.
Orthogonal Designs Of Kharaghani Type: I, C. Koukouvinos, Jennifer Seberry
Orthogonal Designs Of Kharaghani Type: I, C. Koukouvinos, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We use an array given in H. Kharaghani, Arrays for orthogonal designs, J. Combin. Designs, 8 (2000), 166-173, to obtain infinite families of 8-variable Kharaghani type orthogonal designs, OD(8t; hi, kl, kl, kl, k2, k2, k2, k2), where k1 and k2 must be the sum of two squares. In particular we obtain infinite families of 8-variable Kharaghani type orthogonal designs, OD(8t; k, k, k, k, k, k, k, k). For odd t orthogonal designs of order ≡ 8( mod 16) can have at most eight variables.
Some Results On Kharaghani Type Orthogonal Designs, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Some Results On Kharaghani Type Orthogonal Designs, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
In this paper we give a general theorem which can be used to multiply the length of amicable sequences keeping the amicability property and the type of the sequences. As a consequence we have that if there exist two, four or eight amicable sequences of length m and type (al, a2), (al, a2, a3, a4) or (al, a2, …, as) then there exist amicable sequences of length ℓ ≡ 0 (mod m) and of the same type. We also present a theorem that produces a set of 2v amicable sequences from a set of v (not necessary amicable) sequences and …
An Algorithm To Find Formulae And Values Of Minors For Hadamard Matrices: Ii, C. Koukouvinos, E. Lappas, M. Mitrouli, Jennifer Seberry
An Algorithm To Find Formulae And Values Of Minors For Hadamard Matrices: Ii, C. Koukouvinos, E. Lappas, M. Mitrouli, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
An algorithm computing the (n — j) x (n — j ) , j = 1, 2, ... minors of Hadamard matrices of order n is presented. Its implementation is analytically described step by step for several values of n and j. For j = 7 the values of minors are computed for the first time. A formulae estimating all the values of (n — j) x (n — j) minors is predicted.
Compression Tolerant Dct Based Image Hash, C. Kailasanathan, R. Safavi-Naini, P. Ogunbona
Compression Tolerant Dct Based Image Hash, C. Kailasanathan, R. Safavi-Naini, P. Ogunbona
Faculty of Informatics - Papers (Archive)
With the advent of Internet image authentication has become a central part of research in security. Since JPEG has recommended discrete cosine transform as one of the steps in image compression systems, a hash function which utilizes discrete cosine decomposition is desirable. In this paper, we propose a discrete cosine based hash function which distinguishes acceptable level of compression from image processing modifications such as Median filtering, Gaussian noise addition, and FMLR attack. To increase manipulation detection, we optimize the number of AC coefficients needed in smoothing.
Sequential Traitor Tracing, R. Safavi-Naini, Yejing Wang
Sequential Traitor Tracing, R. Safavi-Naini, Yejing Wang
Faculty of Informatics - Papers (Archive)
We consider a new type of traitor tracing scheme, called sequential traitor tracing, that protects against rebroadcasting of decrypted content. Sequential traceability (TA) schemes trace all up to c traitors and remove the shortcomings of dynamic tracing schemes. We give two general constructions and show the relationship between c-TA codes and sequential tracing schemes.
A Self-Organizing Map For Adaptive Processing Of Structured Data, Markus Hagenbuchner, A. Sperduti, Ah Chung Tsoi
A Self-Organizing Map For Adaptive Processing Of Structured Data, Markus Hagenbuchner, A. Sperduti, Ah Chung Tsoi
Faculty of Informatics - Papers (Archive)
Recent developments in the area of neural networks produced models capable of dealing with structured data. Here, we propose the first fully unsupervised model, namely an extension of traditional self-organizing maps (SOMs), for the processing of labeled directed acyclic graphs (DAGs). The extension is obtained by using the unfolding procedure adopted in recurrent and recursive neural networks, with the replicated neurons in the unfolded network comprising of a full SOM. This approach enables the discovery of similarities among objects including vectors consisting of numerical data. The capabilities of the model are analyzed in detail by utilizing a relatively large data …
Fully Scalable Texture Coding Of Arbitrarily Shaped Video Objects, H. Danyali, Alfred Mertins
Fully Scalable Texture Coding Of Arbitrarily Shaped Video Objects, H. Danyali, Alfred Mertins
Faculty of Informatics - Papers (Archive)
This paper presents a fully scalable texture coding algorithm for arbitrarily shaped video object based on the 3D-SPIHT algorithm. The proposed algorithm, called Fully Scalable Object-based 3D-SPIHT (FSOB-3DSPIHT), modifies the 3D-SPIHT algorithm to code video objects with arbitrary shape and adds spatial and temporal scalability features to it. It keeps important features of the original 3D-SPIHT coder such as compression efficiency, full embeddedness, and rate scalability. The full scalability feature of the modified algorithm is achieved through the introduction of multiple resolution dependent lists for the sorting stage of the algorithm. The idea of bitstream transcoding without decoding to obtain …
Low Bit Rate Wideband Wi Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak
Low Bit Rate Wideband Wi Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak
Faculty of Informatics - Papers (Archive)
This paper investigates waveform interpolation (WI) applied low bit rate wideband speech coding. An analysis of the evolutionary behaviour of wideband characteristic waveforms (CW) shows that direct application of the classical WI algorithm may not be appropriate for wideband speech. We propose a modification whereby CW quantisation is performed using classical WI decomposition for the low frequency region and noise modelling for the high frequency region. Wideband WI coders incorporating this modification and operating at 4 kbit/s and 6 kbit/s are described. Subjective testing of these coders shows that WI is a promising approach to low bit rate wideband speech …
Robust Non-Interactive Oblivious Transfer, Y. Mu, J. Zhang, V. Varadharajan, Y. X. Lin
Robust Non-Interactive Oblivious Transfer, Y. Mu, J. Zhang, V. Varadharajan, Y. X. Lin
Faculty of Informatics - Papers (Archive)
We present a novel scheme of noninteractive m out of n oblivious transfer, which demonstrates significant improvement over the existing schemes in terms of completeness, robustness and flexibility. This scheme is useful for protection of user privacy in the Internet.
Blind Deconvolution Of Dynamical Systems Using A Balanced Parameterized State Space Approach, Ah Chung Tsoi, L. S. Ma
Blind Deconvolution Of Dynamical Systems Using A Balanced Parameterized State Space Approach, Ah Chung Tsoi, L. S. Ma
Faculty of Informatics - Papers (Archive)
In this paper, the problem of blind deconvolution of dynamical systems is considered using a state space approach. A balanced parameterized canonical form is used as a model for the underlying dynamical system instead of the more common controller or observable canonical form. The results are compared with those obtained using a controller canonical form. It is shown experimentally that using the balanced parameterized canonical form is more robust than the ones using a controller canonical form.
Universal Multimedia Experiences For Tomorrow, F. Pereira, I. Burnett
Universal Multimedia Experiences For Tomorrow, F. Pereira, I. Burnett
Faculty of Informatics - Papers (Archive)
The previous decade has seen a variety of trends and developments in the area of communications and thus multimedia access. While individual, isolated developments produced small advances on the status quo, their combination and cross-fertilization resulted in today's complex but exciting landscape. In particular, we are beginning to see delivery of all types of data for all types of users in all types of conditions. This article discusses the current status of universal multimedia access (UMA) technologies and investigates future directions in this area. Key developments and trends from the last few years have set the scene for ubiquitous multimedia …
A Study On Sound Source Apparent Shape And Wideness, Guillaume Potard, Ian Burnett
A Study On Sound Source Apparent Shape And Wideness, Guillaume Potard, Ian Burnett
Faculty of Informatics - Papers (Archive)
This work is intended as an initial investigation into the perception of wideness and shape of sound sources. A method that employs mUltiple uncorrelated point sources is used in order to form "sound shapes". Several experiments were carried out in which, after some initial training, subjects were asked to indicate the shapes that were being played. Results indicate that vertical and horizontal source wideness are easily perceived and scenes that use broad sound sources are preferred 70% of the time over point source versions. However, shape perception was found to be ambiguous except for certain types of signals where results …
Size And Power Considerations For Testing Loglinear Models Using Divergence Test Statistics, Noel A. Cressie, L Pardo, M Del Carmen Pardo
Size And Power Considerations For Testing Loglinear Models Using Divergence Test Statistics, Noel A. Cressie, L Pardo, M Del Carmen Pardo
Faculty of Informatics - Papers (Archive)
In this article, we assume that categorical data are distributed according to a multinomial distribution whose probabilities follow a loglinear model. The inference problem we consider is that of hypothesis testing in a loglinear-model setting. The null hypothesis is a composite hypothesis nested within the alternative. Test statistics are chosen from the general class of divergence statistics. This article collects together the operating characteristics of the hypothesis test based on both asymptotic (using large-sample theory) and finite-sample (using a designed simulation study) results. Members of the class of power divergence statistics are compared, and it is found that the Cressie-Read …
Plenary: Nonparametric Hypothesis Testing For A Spatial Signal, Noel A. Cressie
Plenary: Nonparametric Hypothesis Testing For A Spatial Signal, Noel A. Cressie
Faculty of Informatics - Papers (Archive)
Summary form only given. Nonparametric hypothesis testing for a spatial signal can involve a large number of hypotheses. For instance, two satellite images of the same scene, taken before and after an event, could be used to test a hypothesis that the event has no environmental impact. This is equivalent to testing that the mean difference of "after-before" is zero at each of the (typically thousands of) pixels that make up the scene. In such a situation, conventional testing procedures that control the overall Type I error deteriorate as the number of hypotheses increase. Powerful testing procedures are needed for …
In Process Surface Roughness Estimation In Grinding, Li Xue, Fazel Naghdy, Christopher David Cook
In Process Surface Roughness Estimation In Grinding, Li Xue, Fazel Naghdy, Christopher David Cook
Faculty of Informatics - Papers (Archive)
An intelligent sensor system for on-line estimation of surface roughness in the grinding process is developed. The system consists of a statistical signal processing algorithm and a neuro-fuzzy model of surface roughness. The model is established using a set of experimental data. The sensor signals of acoustic emission CAE), normal force and tangential force generated in grinding zone are acquired online in real time. The surface roughness of the ground workpiece is measured offline and used as the target output of the model. A first order Sugeno-type neuro-fuzzy inference system is employed to optimize the model by minimizing a sum …