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Articles 1 - 30 of 74
Full-Text Articles in Physical Sciences and Mathematics
Skill Acquisition In Transfer Of Manipulation Skills From Human To Machine Through A Haptic Virtual Environment, Y. Chen, F. Naghdy
Skill Acquisition In Transfer Of Manipulation Skills From Human To Machine Through A Haptic Virtual Environment, Y. Chen, F. Naghdy
Faculty of Informatics - Papers (Archive)
A new paradigm for programming a robotics manipulator is developed. It is intended that the teaching of the machine will begin with the necessary skills being demonstrated by the human operator in a virtual environment with tactile sensing (haptics). Position and contact force and torque data generated in the virtual environment combined with a priori knowledge about the task is used to identify and learn the skills in the newly demonstrated tasks and then to reproduce them in the robotics system. The peg-in-hole insertion problem is used as a case study. The overall concept is described. The methodologies developed to …
Routing In Mobile Ad Hoc Networks With Global Knowledge, D. Platt
Routing In Mobile Ad Hoc Networks With Global Knowledge, D. Platt
Faculty of Informatics - Papers (Archive)
This paper describes a method of routing in mobile ad hoc networks. The problem is exacerbated by the fact that the radio links between the nodes of the network are continually being made and broken. The method consists of using the known connections to construct a "map" of the network which is intended to reproduce the geographical layout of the network at any time. An algorithm is described which finds a route from one node to another by always attempting to move geographically closer to the destination at every hop. This produces nearly optimal performance with very short computation time. …
Improved Utilisation In Ip Networks Using Multiple Path Routing, D. Platt
Improved Utilisation In Ip Networks Using Multiple Path Routing, D. Platt
Faculty of Informatics - Papers (Archive)
This paper considers routing in an IP network running a routing protocol such as OSPF It takes as a benchmark a routing scheme. which computes a single lowest cost path between every source/destination pair. It proposes two more schemes which each generate two routes for each source/destination pair. The second scheme uses the present lowest cost route and the previous lowest cost route, different from the present one. The third scheme uses the present lowest cost route and re-computes a route by removing all the links used in the first route and using the Dijkstra algorithm. A number of tests …
Scalable Routing Strategy For Dynamic Zones-Based Manets, Mehran Abolhasan, Tadeusz A. Wysocki, E. Dutkiewicz
Scalable Routing Strategy For Dynamic Zones-Based Manets, Mehran Abolhasan, Tadeusz A. Wysocki, E. Dutkiewicz
Faculty of Informatics - Papers (Archive)
This paper presents a new routing strategy for mobile ad hoc networks, called dynamic zone-based topology routing protocol (DZTR). We introduce new strategies to maintain up-to-date intrazone and interzone topology information at each node. We also propose a GPS-based location tracking mechanism, which reduces route discovery area and the number of nodes queried to find the required destination. Our routing strategy has been designed to work with a dynamic zone, which contains a set of member nodes. Every node outside a zone is called a single-state node. We perform theoretical performance analysis, which shows that our network topology creation process …
Remote Collaborative Teaching For Computer Science, A. Fuller, Penelope Mcfarlane, K. Lam
Remote Collaborative Teaching For Computer Science, A. Fuller, Penelope Mcfarlane, K. Lam
Faculty of Informatics - Papers (Archive)
Like many western universities, the University of Wollongong (Australia) is offering degrees to an increasing number of offshore students. Their usual offshore teaching model involves intensive delivery of course material. Disadvantages of this model include the apparent secondary nature of the offshore academic's role and its unsuitability for technical subjects. In this paper, the authors discuss experiments using Internet technologies to overcome those disadvantages.
Enhancing Team Teaching With Webct, Gene Awyzio, Penelope Mcfarlane, A. Fuller
Enhancing Team Teaching With Webct, Gene Awyzio, Penelope Mcfarlane, A. Fuller
Faculty of Informatics - Papers (Archive)
Team teaching has been shown to benefit both students and faculty and we have previously shown a class management package (WebCT) supports an interdisciplinary team environment. However, what happens when the team constituency changes? This paper explores our experience with this situation as we depend on WebCT to facilitate adapting to such a change, further highlighting that WebCT is an integral member of our team.
Experiences Using Case Studies To Teach Risk, A. Fuller, Khin Than Win, L. Dei
Experiences Using Case Studies To Teach Risk, A. Fuller, Khin Than Win, L. Dei
Faculty of Informatics - Papers (Archive)
Most software development projects today are facing increased risks. Despite this risk management planning is virtually nonexistent, as managers have not been trained in risk management. Few current software engineering curricula provide comprehensive coverage of risk, nor any practical experience in risk assessment. In this paper we discuss our experience using case studies to teach risk as part of a final year course in software process management with a view to determining the effectiveness of the particular case studies. This experience will be used as a foundation for implementing the full semester course in 2003.
Asymptotic Solitons For A Higher-Order Modified Korteweg–De Vries Equation, Timothy R. Marchant
Asymptotic Solitons For A Higher-Order Modified Korteweg–De Vries Equation, Timothy R. Marchant
Faculty of Informatics - Papers (Archive)
Solitary wave interaction for a higher-order modified Korteweg–de Vries (mKdV) equation is examined. The higher-order mKdV equation can be asymptotically transformed to the mKdV equation, if the higher-order coefficients satisfy a certain algebraic relationship. The transformation is used to derive the higher-order two-soliton solution and it is shown that the interaction is asymptotically elastic. Moreover, the higher-order phase shifts are derived using the asymptotic theory. Numerical simulations of the interaction of two higher-order solitary waves are also performed. Two examples are considered, one satisfies the algebraic relationship derived from the asymptotic theory, and the other does not. For the example …
Traffic Engineering For Mpls-Based Virtual Private Networks, Chuntung Chou
Traffic Engineering For Mpls-Based Virtual Private Networks, Chuntung Chou
Faculty of Informatics - Papers (Archive)
This paper considers the traffic engineering of MPLS-based virtual private networks (VPNs) with multiple classes of service. We focus on two main issues. Firstly, we point out that the one LSP per ingress-egress pair constraint can be relaxed for the case of MPLS-based VPNs due to the ease in classifying flows on a per-VPN basis. This allows us to use LSP with finer granularity and thus better load balancing. Secondly, we point out that the single objective traffic engineering formulations proposed in literature address only one particular aspect of the traffic engineering problem. We propose a multiobjective traffic engineering problem …
Spanning The 4 Kbps Divide Using Pulse Modeled Residual, J Lukasiak, I. Burnett
Spanning The 4 Kbps Divide Using Pulse Modeled Residual, J Lukasiak, I. Burnett
Faculty of Informatics - Papers (Archive)
This paper reports a scalable method for coding the LP residual. The scalable method is capable of increasing the accuracy of the reconstructed speech from a parametric representation at low rates to a more accurate waveform matched representation at higher rates. The method entails pitch length segmentation, decomposition into pulsed and noise components and modeling of the pulsed components using a fixed shape pulse model in a closed-loop, analysis by synthesis system.
Scalable Decomposition Of Speech Waveforms, J Lukasiak, I. Burnett
Scalable Decomposition Of Speech Waveforms, J Lukasiak, I. Burnett
Faculty of Informatics - Papers (Archive)
Decomposition of speech signals into periodic and noise components is widely used in speech coding to facilitate efficient compression. Existing decomposition schemes are too inflexible to model transient changes in the speech signal, require high delay or produce a large parameter set that is not scalable to low rates. This paper proposes a technique that requires only a single frame of speech and produces a scalable decomposition. The latter allows reconstruction accuracy to be varied according to the bit rate available.
The Analysis Of Speech Codecs Using Psychoacoustic Measures, M. Raad, C. H. Ritz, I. Burnett, Alfred Mertins
The Analysis Of Speech Codecs Using Psychoacoustic Measures, M. Raad, C. H. Ritz, I. Burnett, Alfred Mertins
Faculty of Informatics - Papers (Archive)
This paper analyses two narrowband speech codecs, the 4.8 kbit/s FS1016 coder and the 8 kbit/s G729 coder, using objective psychoacoustic measures. Four measures are used: loudness, sharpness, roughness and tonality. The results show sharpness and roughness as the two major contributing factors to the subjective difference between the two coders.
Extending Waveform Interpolation To Wideband Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak
Extending Waveform Interpolation To Wideband Speech Coding, C. H. Ritz, I. Burnett, Jason Lukasiak
Faculty of Informatics - Papers (Archive)
This paper investigates the extension of waveform interpolation (WI) to wideband speech coding. Included is an analysis of the evolutionary behaviour of wideband speech and the consequences for WI. We highlight problems associated with direct application of the classical WI algorithm applied to wideband speech.
On Full Orthogonal Designs In Order 56, S. Georgiou, C. Koukouvinos, Jennifer Seberry
On Full Orthogonal Designs In Order 56, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We find new full orthogonal designs in order 56 and show that of 1285 possible OD(56; s1, s2, s3, 56—s1—s2-s3) 163 are known, of 261 possible OD(56; s1, s2, 56—s1—s2) 179 are known. All possible OD(56; s1, 56 — s1) are known.
Adaptive Management: What Does It Mean And How Can It Be Used In Fire Management?, R. J. Whelan
Adaptive Management: What Does It Mean And How Can It Be Used In Fire Management?, R. J. Whelan
Faculty of Science - Papers (Archive)
‘Adaptive Management’ is becoming a frequently heard term but it is a much misunderstood concept. It does not mean that developments can go ahead and be ‘adapted’ if detrimental effects are discovered! Its greatest value is in defining an experimental approach to land management in situations where scientific knowledge is lacking but where immediate actions are required. This is especially important where doing nothing might conceivably be just as undesirable as applying any of the alternative management options. Given the lack of knowledge of fire responses of much of our native biota, adaptive management is clearly a sensible approach to …
Unified Power Quality Index (Upqi) For Continuous Disturbances, V. J. Gosbell, B. Perera, H. M. Herath
Unified Power Quality Index (Upqi) For Continuous Disturbances, V. J. Gosbell, B. Perera, H. M. Herath
Faculty of Informatics - Papers (Archive)
Power quality indices are being developed that attempt to quantify certain aspects of service quality. There has been considerable amount of work on the characterization of individual types of power quality disturbances and corresponding indices. However, there does not exist in the literature a standard approach that allows one to quantify the overall power quality. This paper proposes a unified power quality index (UPQI) as a useful tool for ranking sites as to their overall power quality.
Calibrating A 4-Wheel Mobile Robot, Phillip J. Mckerrow, D. Ratner
Calibrating A 4-Wheel Mobile Robot, Phillip J. Mckerrow, D. Ratner
Faculty of Informatics - Papers (Archive)
When a mobile robot is constructed the odometry must be calibrated. Calibrating a 4-wheel robot requires the accurate measurement of steering angle as well as translation and rotation. Some measurements are made with a tape measure and some with ultrasonic sensors. The measurements are used to determine the parameters of the odometry calibration matrix and the steering kinematic model. A procedure for calibrating a 4-wheel robot is discussed.
Analysis And Representation Of Statistical Performance Of Jpeg2000 Encoded Image Over Wireless Channels, J. He, Z. Yang, D. Yang, Z. Tang, J. Hu, Chuntung Chou
Analysis And Representation Of Statistical Performance Of Jpeg2000 Encoded Image Over Wireless Channels, J. He, Z. Yang, D. Yang, Z. Tang, J. Hu, Chuntung Chou
Faculty of Informatics - Papers (Archive)
JPEG2000 is a new coming image standard. In this paper we analyze the performance of error resilience tools in JPEG2000, and present an analytical model to estimate the quality of JPEG2000 encoded image transmitted over wireless channels. The effectiveness of the analytical model is validated by simulation results. Furthermore, analytical model is utilized by the base station to design efficient unequal error protection schemes for JPEG2000 transmission. In the design, a utility function is defined to make a tradeoff between the image quality and the cost for transmitting the image over a wireless channel.
Highly Scalable Image Compression Based On Spiht For Network Applications, H. Danyali, Alfred Mertins
Highly Scalable Image Compression Based On Spiht For Network Applications, H. Danyali, Alfred Mertins
Faculty of Informatics - Papers (Archive)
We propose a highly scalable image compression scheme based on the set partitioning in hierarchical trees (SPIHT) algorithm. Our algorithm, called highly scalable SPIHT (HS-SPIHT), supports spatial and SNR scalability and provides a bitstream that can be easily adapted (reordered) to given bandwidth and resolution requirements by a simple transcoder (parser). The HS-SPIHT algorithm adds the spatial scalability feature without sacrificing the SNR embeddedness property as found in the original SPIHT bitstream. HS-SPIHT finds applications in progressive Web browsing, flexible image storage and retrieval, and image transmission over heterogeneous networks.
Decoding Of Images Using Soft-Bits And Markov Random Field Modeling, Alfred Mertins, O. Jamart
Decoding Of Images Using Soft-Bits And Markov Random Field Modeling, Alfred Mertins, O. Jamart
Faculty of Informatics - Papers (Archive)
We combine soft-bit decoding with Markov random field modeling of source signals and apply the proposed technique to image communication over noisy channels. No redundancy is added by the encoder in the form of channel codes. For error correction and concealment, the decoder relies only on the bit-reliability information extracted at the channel output and the random field modeling of natural images. The results obtained show that the proposed method yields excellent performance even under extremely noisy conditions.
Secure Authorization, Access Control And Data Integrity In Bluetooth, L. Nguyen, R. Safavi-Naini, Willy Susilo, Tadeusz A. Wysocki
Secure Authorization, Access Control And Data Integrity In Bluetooth, L. Nguyen, R. Safavi-Naini, Willy Susilo, Tadeusz A. Wysocki
Faculty of Informatics - Papers (Archive)
The Bluetooth standard has a provision for mutual authentication of connecting devices but not their actual users and allows access control during connection setup only. We propose a user authorization and pairing (UAP) application, that has the ability to perform authentication and authorization of users using role based model. The pairing procedure, which exchanges link key between devices, is also performed as a part of the user authorization process. The integrity of the message is guaranteed by using message authentication codes. We also extend an attack on a short PIN during the pairing procedure for devices compliant with the Bluetooth …
Securing Handheld Devices, Willy Susilo
Securing Handheld Devices, Willy Susilo
Faculty of Informatics - Papers (Archive)
Handheld devices are becoming an indispensable part of everyday life. In this paper, we review the security of handheld devices, which are based on the Pocket PC operating system. We then identify the risks and threats of having these handheld devices connected to the Internet, and propose several methods to protect against the threats. We point out some advantages and security threats of porting server applications to handheld devices. We also consider the newest technology in mobile applications using the Microsoft's NET framework and provide the security risk analysis for it. We conclude the paper with an open problem.
On The (V,5,Λ)-Family Of Bhaskar Rao Designs, G. R. Chaudhry, M. Greig, Jennifer Seberry
On The (V,5,Λ)-Family Of Bhaskar Rao Designs, G. R. Chaudhry, M. Greig, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We establish that the necessary conditions for the existence of Bhaskar Rao designs of block size five are : i). λ(v - 1) ≡ 0 (mod 4) ii). λv(v - 1) ≡ 0 (mod 40) iii). 2|λ. We show these conditions are sufficient: for λ = 4 if v > 215, with 10 smaller possible exceptions and one definite exception at v = 5; for λ = 10 if v > 445, with 11 smaller possible exceptions, and one definite exception at v = 5; and for λ = 20, with the possible exception of v = 32; we also give a …
Necessary And Sufficient Conditions For Three And Four Variable Orthogonal Designs In Order 36, S. Georgiou, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Necessary And Sufficient Conditions For Three And Four Variable Orthogonal Designs In Order 36, S. Georgiou, C. Koukouvinos, M. Mitrouli, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We use a new 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. Then we use these sequences to construct a series of new three and four variable orthogonal designs in order 36. We show that the necessary conditions plus (.s1, s2, s3, s4) not equal to 12816 18 816 221313 26721 36 816 4889 12825 191313 23 424 289 9 381015 8899 14425 22 916 are sufficient for the existence of an OD(36; s1, s2 s3, s4) constructed using four circulant …
Compression Performance Of Jpeg Encryption Scheme, C. Kailasanathan, R. Safavi-Naini, P. Ogunbona
Compression Performance Of Jpeg Encryption Scheme, C. Kailasanathan, R. Safavi-Naini, P. Ogunbona
Faculty of Informatics - Papers (Archive)
Recent development in the Internet and Web based technologies require faster communication of multimedia data in a secure form. A number of encryption schemes for MPEG have been proposed. In this paper, we evaluate the compression performance of JPEG which has been encrypted with the zig-zag permutation algorithm, suggest a security enhancement to the scheme, and propose an alternative to entropy coding recommended by JPEG to compensate for the compression drop occurring due to permutation.
On A Use Of Golay Sequences For Asynchronous Ds Cdma Applications, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki
On A Use Of Golay Sequences For Asynchronous Ds Cdma Applications, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki
Faculty of Informatics - Papers (Archive)
Golay complementary sequences, often referred to as Golay pairs, are characterised by the property that the sum of their aperiodic autocorrelation functions equals to zero, except for the zero shift. Because of this property, Golay complementary sequences can be utilised to construct Hadamard matrices defining sets of orthogonal spreading sequences for DS CDMA systems of the lengths not necessary being a power of 2. In the paper, we present an evaluation, from the viewpoint of asynchronous DS CDMA applications, of some sets of spreading sequences derived from Golay complementary sequences. We then modify those sets of sequences to enhance their …
Face Recognition Using A Similarity-Based Measure In Image Database For Crime Investigation, V. Srisarkun, J. Cooper
Face Recognition Using A Similarity-Based Measure In Image Database For Crime Investigation, V. Srisarkun, J. Cooper
Faculty of Informatics - Papers (Archive)
A method to handle searching a face image database (FID) is proposed to support police officers when searching criminal records from a central registration database system (CRDS). The proposed method assumes that each FID consists of a fixable object and object correlation. The proposed method employs a database search, so that all images with a similarity-based measure are retrieved. Consequently, the proposed method is much faster than sequential searching, especially when an additional set of attributes, like scar, is defined. Moreover it requires less storage space.
Modulated, Perfect Reconstruction Filterbanks With Integer Coefficients, Alfred Mertins, T. Karp
Modulated, Perfect Reconstruction Filterbanks With Integer Coefficients, Alfred Mertins, T. Karp
Faculty of Informatics - Papers (Archive)
We present design methods for perfect reconstruction (PR) integer-modulated filterbanks, including biorthogonal (low-delay) filterbanks. Both the prototype filter and the modulation sequences are composed of integers, thus allowing efficient hardware implementations and fast computation. To derive such filterbanks, we first start with the PR conditions known for cosine modulation and extend them to more general, integer modulation schemes. For the design of biorthogonal PR integer prototypes, a lifting strategy is introduced. To find suitable integer modulation schemes, new algebraic methods are presented. We show solutions where the PR conditions on the prototype filters and the modulation matrices are entirely decoupled …
Streptococcus Pyogenes Prtfii, But Not Sfbi, Sfbii Or Fbp54, Is Represented More Frequently Among Invasive-Disease Isolates Of Tropical Australia, A. Delvecchio, B. J. Currie, Jason D. Mcarthur, Mark J. Walker, K. S. Sriprakash
Streptococcus Pyogenes Prtfii, But Not Sfbi, Sfbii Or Fbp54, Is Represented More Frequently Among Invasive-Disease Isolates Of Tropical Australia, A. Delvecchio, B. J. Currie, Jason D. Mcarthur, Mark J. Walker, K. S. Sriprakash
Faculty of Science - Papers (Archive)
Streptococcus pyogenes (group A streptococcus) strains may express several distinct ®bronectinbinding proteins (FBPs) which are considered as major streptococcal adhesins. Of the FBPs, SfbI was shown in Šitro to promote internalization of the bacterium into host cells and has been implicated in persistence. In the tropical Northern Territory, where group A streptococcal infection is common, multiple genotypes of the organism were found among isolates from invasive disease cases and no dominant strains were observed. To determine whether any FBPs is associated with invasive disease propensity of S. pyogenes, we have screened streptococcal isolates from bacteraemic and necrotizing fasciitis patients and …
Frame Bounds For Biorthogonal Cosine-Modulated Filter Banks, Alfred Mertins
Frame Bounds For Biorthogonal Cosine-Modulated Filter Banks, Alfred Mertins
Faculty of Informatics - Papers (Archive)
We derive explicit expressions for the eigenvalues of the frame operator for cosine-modulated filter banks. The filter banks may be critically sampled or oversampled by an integer factor. The analysis of low-delay, biorthogonal filter banks shows that prototypes solely designed to minimize the stopband energy may lead to wide open frames and thus to an undesirable numerical behavior. Because the computational cost of determining the frame bounds with the proposed method is very low, we can directly use the bounds during prototype optimization and obtain prototypes with minimum stopband energy under the condition of fixed frame bounds.