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2008

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Articles 1291 - 1320 of 1335

Full-Text Articles in Computer Sciences

Covert Encryption And Document Authentication Using Texture Coding, Jonathan Blackledge, Mary Hallot Jan 2008

Covert Encryption And Document Authentication Using Texture Coding, Jonathan Blackledge, Mary Hallot

Articles

With the improvements in the quality of Commercial-Off-The-Shelf (COTS) printing and scanning devices, the ability to counterfeit documents has become a widespread problem. Consequently, there has been an increasing demand to develop digital watermarking techniques which can be applied to both electronic and printed images (and documents) that can be authenticated, prevent unauthorized copying and withstand abuse and degradation. In this paper , a new approach to digital watermarking is presented and a range of possible applications are considered. The process is defined by using concepts and techniques borrowed from Cryptography. It is based on computing a 'scramble image' by …


Book Review: Challenges To Digital Forensic Evidence, Gary C. Kessler Jan 2008

Book Review: Challenges To Digital Forensic Evidence, Gary C. Kessler

Publications

This document is Dr. Kessler's review of Challenges to Digital Forensic Evidence, by Fred Cohen. Fred Cohen & Associates, 2008. ISBN 1-878109-41-3


Anti-Phishing Models: Main Challenges, Edina Hatunic-Webster Jan 2008

Anti-Phishing Models: Main Challenges, Edina Hatunic-Webster

Conference papers

Phishing is a form of online identity theft in which the attacker attempts to fraudulently retrieve a legitimate user's account information, logon credentials or identity information in general. The compromised information is then used for withdrawing money online, taking out cash advances, or making purchases of goods and services on the accounts. Various solutions have been proposed and developed in response to phishing. As phishing is a business problem, the solutions target both non-technical and technical areas. This paper investigates the current anti-phishing solutions and critically reviews their usage, security weaknesses and their effectiveness. The analysis of these models points …


Tunable True-Time Delay Unit Based On Opto-Vlsi Processing, Feng Xiao, Budi Juswardy, Kamal Alameh Jan 2008

Tunable True-Time Delay Unit Based On Opto-Vlsi Processing, Feng Xiao, Budi Juswardy, Kamal Alameh

Research outputs pre 2011

A novel tunable true-time delay unit is proposed and demonstrated. The unit is based on the use of an Opto-VLSI processor that dynamically selects a single waveband or multiple wavebands from an RF-modulated broadband optical signal and routes them to a high-dispersion fiber for arbitrary time delay synthesis. Experimental results demonstrate continuously tunable time delay of up to 4 ns.


Obstacle Detection And Spectral Discrimination Using Multi-Wavelength Motionless Wide Angle Laser Scanning, Kaveh Sahba, Kamal Alameh, Clifton Smith Jan 2008

Obstacle Detection And Spectral Discrimination Using Multi-Wavelength Motionless Wide Angle Laser Scanning, Kaveh Sahba, Kamal Alameh, Clifton Smith

Research outputs pre 2011

Static laser scanning over a wide angle is demonstrated by ranging to 20 laser beams generated by a novel cylindrical quasi-cavity waveguide, using laser triangulation. Baseline distances and outgoing angles unique to each laser beam are calculated by modelling the triangulation arrangement using a system of linear equations and plotting principal rays. The quasi-cavity waveguide, imaging lens and focal plane are also plotted. The system is calibrated by finding optimal values for uncertain instrumental parameters using constrained non-linear optimization. Distances calculated over 5m indoors result in accuracies above 93%. Discrete laser spectroscopy using 640nm and 785nm laser diodes is also …


A Tunable Multiwavelength Laser Employing A Semiconductor Optical Amplifier And An Opto-Vlsi Processor, Muhsen Aljada, Kamal Alameh, Yong T. Lee Jan 2008

A Tunable Multiwavelength Laser Employing A Semiconductor Optical Amplifier And An Opto-Vlsi Processor, Muhsen Aljada, Kamal Alameh, Yong T. Lee

Research outputs pre 2011

We propose and experimentally demonstrate a stable tunable multiwavelength laser employing a semiconductor optical amplifier (SOA) in conjunction with an opto-very-large-scale-integration (VLSI) processor. By uploading digital phase holograms onto the opto-VLSI processor, the amplified spontaneous emission of the SOA is arbitrarily sliced and injected back into the SOA to generate multiple lasing wavelengths with a linewidth of 0.5 nm. Experimental results demonstrate a tunable multiwavelength laser with a tuning range from 1528 to 1533 nm with power fluctuations of less than 0.5 dB.


Current Challenges Facing Information And Communications Technology: A Manifesto For Change, Donald Mcdermid Jan 2008

Current Challenges Facing Information And Communications Technology: A Manifesto For Change, Donald Mcdermid

Research outputs pre 2011

A distinction is drawn concerning the true nature of Information and Communications Technology (ICT) which previously was seen as technology-focused or techno centric but actually concerns transformation and the management of change in business (socio-techno centric). Current issues and challenges in ICT are examined and future trends and directions highlighted. This leads to a manifesto for change outlining a coherent approach to transforming ICT into a resource which fully contributes to business. Finally given this manifesto, challenges for tertiary education are outlined.


Evaluation Of An Optical Image Sensor For Use In The Microphotonic Real-Time Vegetation Discrimination System, Arie Paap, Sreten Askraba, Kamal Alameh, John Rowe Jan 2008

Evaluation Of An Optical Image Sensor For Use In The Microphotonic Real-Time Vegetation Discrimination System, Arie Paap, Sreten Askraba, Kamal Alameh, John Rowe

Research outputs pre 2011

A comparison between the performance of a commercially available line scan camera and a linear sensor array employed in a micro-photonic real-time vegetation discrimination system for use in selective herbicide spraying systems is presented.


A Type Of Variation Of Hamilton Path Problem With Applications, Jitian Xiao, Jun Wang Jan 2008

A Type Of Variation Of Hamilton Path Problem With Applications, Jitian Xiao, Jun Wang

Research outputs pre 2011

This paper describes a type of variation of the Hamilton path problem that can be applied to a type of applications. Unlike the original Hamilton path problem, the variation always has a solution. The problem of finding solutions to the variation of the Hamilton path problem is NP-complete. A heuristic for finding solutions to the problem is developed and analyzed. The heuristic is then applied to a real application scenario in the area of spatial cluster scheduling in spatial join processing. Experiments have demonstrated that the proposed method generates better cluster sequence than existing algorithms.


Opto-Vlsi Based Broadband Reconfigurable Optical Add-Drop Multiplexer, Feng Xiao, Budi Juswardy, Kamal Alameh Jan 2008

Opto-Vlsi Based Broadband Reconfigurable Optical Add-Drop Multiplexer, Feng Xiao, Budi Juswardy, Kamal Alameh

Research outputs pre 2011

In this paper, a reconfigurable optical add/drop multiplexer (ROADM) structure using an Opto-VLSI processor, two arrayed waveguide grating de/multiplexers (AWGs) and a custom-made fiber array is described. The fiber array consist of N pairs of upper and lower fibers, where each pair could function as an add, a drop or a thru multiplexers depending on the hologram generated by the Opto-VLSI processor. Experimental results show that the proposed ROADM structure has an average insertion loss of 5.5 dB for all the functions and a uniformity of 0.3 dB over a wide wavelength range from 1524 nm to 1576 nm. A …


Opto-Vlsi-Based Reconfigurable Microwave Photonic Transversal Filter With Positive And Negative Coefficients, Feng Xiao, Budi Juswardy, Kamal Alameh Jan 2008

Opto-Vlsi-Based Reconfigurable Microwave Photonic Transversal Filter With Positive And Negative Coefficients, Feng Xiao, Budi Juswardy, Kamal Alameh

Research outputs pre 2011

A novel reconfigurable microwave photonic filter structure with positive and negative coefficients is proposed and demonstrated. The filter structure comprises two arrayed waveguide gratings, a custom-made fiber array, high-dispersion fibres, and a reconfigurable opto-VLSI processor. Positive and negative filter weights can flexibly be synthesised to realise arbitrary transfer functions. Experimental results are presented, which demonstrate the principle of the proposed filter structure.


Reconfigurable Multi-Passband Optical Filter Using Opto-Vlsi Processor, Muhsen Aljada, Kamal Alameh Jan 2008

Reconfigurable Multi-Passband Optical Filter Using Opto-Vlsi Processor, Muhsen Aljada, Kamal Alameh

Research outputs pre 2011

A reconfigurable multi-passband optical filter of 0.5 nm linewidth and a tuning range of 8 nm is demonstrated using an opto-VLSI processor. The wavelength tunability is performed using digital phase holograms uploaded on the opto-VLSI processor.


You've Got Mail: Accountability And End User Attitudes To Email Management, Mark Brogan, Susan Vreugdenburg Jan 2008

You've Got Mail: Accountability And End User Attitudes To Email Management, Mark Brogan, Susan Vreugdenburg

Research outputs pre 2011

In a pioneering ethnographic study of end user responses to the problem of ‘information overload’ Whittaker and Sidner (1996) found that the design of systems primarily as methods of asynchronous communication, posed significant information management problems for users. In another contemporaneous study, David Bearman (1993) extended understanding of the implications of end user email management behavior by identifying significant accountability implications for organizations arising from the use of email. Recent case studies in the United States and Australia (Leopold, 2008; Raleigh Chronicle, 2008; Strutt, and Taylor, 2007) have once again focused attention on the accountability consequences for Government of email …


A Novel Wide-Angle Laser Triangulation Method For Obstacle Detection, Kaveh Sahba, Kamal Alameh, Clifton Smith Jan 2008

A Novel Wide-Angle Laser Triangulation Method For Obstacle Detection, Kaveh Sahba, Kamal Alameh, Clifton Smith

Research outputs pre 2011

Indoor active triangulation to laser spots generated by quasi-cylindrical cavity is demonstrated. Principal ray trajectory is modeled using a system of linear equations and fundamental ray geometry. Each ray’s unique outgoing angle and baseline is calculated and used to derive the range to the corresponding spot. Above 98% accuracy is achieved over an approximate range of 5m, demonstrating a novel motionless laser scanning technique with a wide scanned angle and no moving parts.


A Novel Mobile Wimax Solution For Higher Throughput, Iftekhar Ahmad, Daryoush Habibi Jan 2008

A Novel Mobile Wimax Solution For Higher Throughput, Iftekhar Ahmad, Daryoush Habibi

Research outputs pre 2011

The IEEE 802.16 standard, also known as WiMAX, has emerged as an exciting technology for broadband wireless communications with potentials to offer high throughput and support high bandwidth demanding applications. WiMAX, however, has yet to prove its effectiveness when the end terminals are not fixed and have the capacity to move from one place to another at different speeds. Recent studies suggest that while WiMAX (802.16e) has the potential to deliver a data rate up to 75 Mb/s for fixed wireless communications, it fails drastically for mobile wireless communications, often providing a data rate less than 1 Mb/s when the …


A Proactive Forward Error Control Scheme For Mobile Wimax Communication, Iftekhar Ahmad, Daryoush Habibi Jan 2008

A Proactive Forward Error Control Scheme For Mobile Wimax Communication, Iftekhar Ahmad, Daryoush Habibi

Research outputs pre 2011

The IEEE 802.16 standard, also known as WiMAX, has yet to prove its effectiveness when the end terminals are not static and free to move at vehicular speeds. High bit error rate caused by multipath fading at high vehicular speeds, is the key reason for low throughput at high speeds. Standard error control mechanisms like transmission control protocol (TCP) and forward error correction (FEC) have limited impact on the overall throughput at vehicular speeds. In this paper, we propose a proactive FEC scheme that adjusts the FEC code size based on the estimated bit error rate at various vehicular speeds. …


Fast Evaluation Of The Square Root And Other Nonlinear Functions In Fpga, Stefan Lachowicz, Hans-Joerg Pfleiderer Jan 2008

Fast Evaluation Of The Square Root And Other Nonlinear Functions In Fpga, Stefan Lachowicz, Hans-Joerg Pfleiderer

Research outputs pre 2011

The paper presents a novel method of evaluating the square root function in FPGA. The method uses a linear approximation subsystem with a reduced size of a look-up table. The reduction in the size of the lookup table is twofold. Firstly, a simple linear approximation subsystem uses the lookup table only for the node points. Secondly, a concept of a variable step look-up table is introduced, where the node points are not uniformly spaced, but the spacing is determined by how close to the linear function the approximated function is. The proposed method of evaluating nonlinear function and specifically the …


The Use Of Neural Networks In The Prediction Of The Stock Exchange Of Thailand (Set) Index, Suchira Chaigusin, Chaiyaporn Chirathamjaree, Judith Clayden Jan 2008

The Use Of Neural Networks In The Prediction Of The Stock Exchange Of Thailand (Set) Index, Suchira Chaigusin, Chaiyaporn Chirathamjaree, Judith Clayden

Research outputs pre 2011

Prediction of stock prices is an issue of interest to financial markets. Many prediction techniques have been reported in stock forecasting. Neural networks are viewed as one of the more suitable techniques. In this study, an experiment on the forecasting of the Stock Exchange of Thailand (SET) was conducted by using feedforward backpropagation neural networks. In the experiment, many combinations of parameters were investigated to identify the right set of parameters for the neural network models in the forecasting of SET. Several global and local factors influencing the Thai stock market were used in developing the models, including the Dow …


Towards Automated Test Sequence Generation, Usman Farooq, Chiou Peng Lam, Huaizhong Li Jan 2008

Towards Automated Test Sequence Generation, Usman Farooq, Chiou Peng Lam, Huaizhong Li

Research outputs pre 2011

The article presents a novel control-flow based test sequence generation technique using UML 2.0 activity diagram, which is a behavioral type of UML diagram. Like other model-based techniques, this technique can be used in the earlier phases of the development process owing to the availability of the design models of the system. The activity diagram model is seamlessly converted into a colored Petri net. We proposed a technique that enables the automatic generation of test sequences according to a given coverage criteria from the execution of the colored Petri nets model. Two types of structural coverage criteria for AD based …


Supporting Component Selection With A Suite Of Classifiers, Valerie Maxville, Chiou Peng Lam, J Armarego Jan 2008

Supporting Component Selection With A Suite Of Classifiers, Valerie Maxville, Chiou Peng Lam, J Armarego

Research outputs pre 2011

Software selection involves the assimilation of information and results for each candidate to enable a comparison for decisions to be made. The processes and tools developed assist with software selection to enhance quality, documentation and repeatability. The CdCE process aims to retain and document the information used in selection to assist decisions and to document them for reference as the system evolves. This paper describes the CdCE process and our approach to assist the shortlisting of candidates through a suite of classifiers. The application of the suite is illustrated using a selection and evaluation case study. Applying this approach helps …


Morphology Independent Dynamic Locomotion Control For Virtual Characters, Adrian Boeing Jan 2008

Morphology Independent Dynamic Locomotion Control For Virtual Characters, Adrian Boeing

Research outputs pre 2011

Physically based animation of virtual characters is an attractive technology for computer games. It enables characters to dynamically react to interactions with the environment. Existing dynamic simulation controllers are often complex to understand and manipulate, and so are of limited use for animators. This paper presents an extended spline-based control strategy similar to splines used in standard keyframe animation techniques. Unlike existing dynamic control strategies, this allows animators to modify the control system parameters in a manner similar to traditional kinematic animation techniques. A genetic algorithm is employed to produce the initial control parameters for the desired gait, and extend …


Mutation Analysis For The Evaluation Of Ad Models, Usman Farooq, Chiou Peng Lam Jan 2008

Mutation Analysis For The Evaluation Of Ad Models, Usman Farooq, Chiou Peng Lam

Research outputs pre 2011

UML has became the industry standard for analysis and design modeling. Model is a key artifact in Model Driven Architect (MDA) and considered as an only concrete artifact available at earlier development stages. Error detection at earlier development stages can save enormous amount of cost and time. The article presents a novel mutation analysis technique for UML 2.0 Activity Diagram (AD). Based on the AD oriented fault types, a number of mutation operators are defined. The technique focuses on the key features of AD and enhances the confidence in design correctness by showing the absence of control-flow and concurrency related …


Optimized Wlan Mac Protocol For Multimedia Applications, Hushairi Zen, Daryoush Habibi, Alexander Rassau, Iftekhar Ahmad Jan 2008

Optimized Wlan Mac Protocol For Multimedia Applications, Hushairi Zen, Daryoush Habibi, Alexander Rassau, Iftekhar Ahmad

Research outputs pre 2011

In this paper we propose an optimized WLAN MAC protocol for multimedia applications. The proposed MAC protocol consist of 3 main optimizing architectures, traffic segregation, specific service interval (SI) for voice and video traffic and smaller contention window (CW). Traffic segregation segregates real-time traffic from best-effort traffic while specific service interval provides voice and video traffic with the SI based on its mean arrival rate. In the contention time frame, the CW is made smaller to reduce delay and increase throughput. Ns2 is used as a simulating tool to compare the results of our proposed protocol with the legacy 802.11 …


Node Admission Control For Multimedia Traffic In Ad-Hoc Wlans, Hushairi Zen, Daryoush Habibi, Iftekhar Ahmad, Alexander Rassau Jan 2008

Node Admission Control For Multimedia Traffic In Ad-Hoc Wlans, Hushairi Zen, Daryoush Habibi, Iftekhar Ahmad, Alexander Rassau

Research outputs pre 2011

In this paper, we design an admission control scheme for ad hoc WLAN based on self-restraint mechanism. The self-restraint admission control mechanism is implemented in each of the wireless nodes instead of the access point (AP). It has two important admission control abilities: first, it can restrain itself from joining the network if the network channel is congested; second, a joining node can drop itself from the network if the channel becomes congested as a result of its admission. We simulate an ad hoc WLAN and show that the self-restraining mechanism works effectively in sustaining traffic in ad hoc WLAN …


Using Design-Based Research For The Evolutionary Development Of An Online Metacognitive Tool, Joseph Luca, Mark Mcmahon Jan 2008

Using Design-Based Research For The Evolutionary Development Of An Online Metacognitive Tool, Joseph Luca, Mark Mcmahon

Research outputs pre 2011

No abstract provided.


Creating A Web-Based Knowledge-Building Team: Design Of Tasks, Scaffolds And Social Affordances, Catherine Mcloughlin, Joseph Luca Jan 2008

Creating A Web-Based Knowledge-Building Team: Design Of Tasks, Scaffolds And Social Affordances, Catherine Mcloughlin, Joseph Luca

Research outputs pre 2011

In a blended learning environment, where students undertake professional skills development in the workplace, a flexible environment is designed in order to support problem solving in project management. The design of the environment, informed by socio-cultural theory, was intended to support knowledge building among students, and in particular to support exchange of ideas, peer review and commentary on solutions presented to problems, and a reflective space for exchange of ideas. The online environment incorporates a number of functional affordances that scaffold knowledge exchange, collaborative tasks and peer commentary. The design features of the online site are described and a proposed …


Integrated True-Time Delay Unit For Broadband Inteference Nulling In Phased-Array Antenna, Budi Juswardy, Kamal Alameh Jan 2008

Integrated True-Time Delay Unit For Broadband Inteference Nulling In Phased-Array Antenna, Budi Juswardy, Kamal Alameh

Research outputs pre 2011

This paper discusses an integrated true-time delay generation unit based on microminiaturisation of photonic and electronic components. The design, simulation, and performance of important building blocks for implementing a true-time delay-based phased-array antenna are presented.


Tunable Photonic Rf Signal Processor Using Opto-Vlsi, Budi Juswardy, Feng Xiao, Kamal Alameh Jan 2008

Tunable Photonic Rf Signal Processor Using Opto-Vlsi, Budi Juswardy, Feng Xiao, Kamal Alameh

Research outputs pre 2011

A tunable photonic RF signal processor is proposed and demonstrated. The filter structure comprises a reconfigurable Opto-VLSI processor for tunability, arrayed waveguide gratings for wavelength slicing and multiplexing, a custom-made fiber array for wavelength routing and dropping, and high-dispersion fibres for true-time delay generation. The processor structure enables positive and negative weights to be synthesised thus realising arbitrary responses. The proof-of-concept of the tunable photonic RF signal processor is experimentally demonstrated.


Systemic Problems In Information Technology Adoption And Use: A Systems Thinking Perspective, Syed Arshad Raza, Craig Standing Jan 2008

Systemic Problems In Information Technology Adoption And Use: A Systems Thinking Perspective, Syed Arshad Raza, Craig Standing

Research outputs pre 2011

Understanding and creating the conditions under which information systems will be embraced by human organizations (thinking systems) remain a high-priority research issue. Despite numerous benefits associated with Information Technology (IT), there exist some intervening factors (systemic problems or issues) that impede technology’s widespread adoption and use in organisations. Established information technology adoption models like TAM, TRA etc. view technology adoption from the users’ perspective without taking a strategic perspective into account. As an alternative focus we suggest that addressing systemic problems can be a method of reducing fundamental barriers to organizational progress. This paper presents some real life examples of …


A Study Into The Forensic Recoverability Of Data From 2nd Hand Blackberry Devices: World-Class Security, Foiled By Humans, Craig Valli, Andrew Jones Jan 2008

A Study Into The Forensic Recoverability Of Data From 2nd Hand Blackberry Devices: World-Class Security, Foiled By Humans, Craig Valli, Andrew Jones

Research outputs pre 2011

Blackberry RIM devices are arguably one of the more secure platforms for email, calendaring and voice. It is one of the few devices in this arena that has approval for carrying restricted security classifications. Blackberry devices do suffer from the same basic fundamental flaw in that they have a human operator. This research was about the blind purchase of Blackberry devices from auctions. Of the 15 Blackberry examined in this study 3 were able to be fully recovered. They all revealed personal and corporate details about the users of the devices.