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2007

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Articles 5191 - 5220 of 6758

Full-Text Articles in Physical Sciences and Mathematics

Surface Characterization Of Thin Film Zno Capacitors By Capacitance-Voltage Measurements, Linda Smith Jan 2007

Surface Characterization Of Thin Film Zno Capacitors By Capacitance-Voltage Measurements, Linda Smith

Electronic Theses and Dissertations

The main objective of the research was the fabrication and characterization of MOS/MIS capacitors with ZnO as the insulating layer. Comparison with the already well known behavior of MOS/MIS capacitors with SiO2 as insulator was used to facilitate determination of the ZnO characteristics. Moreover, thermal annealing of the samples led to increased understanding of the role of defects on the dielectric properties of the ZnO layers in the MOS/MIS devices. Hall-effect transport measurements and x-ray diffraction (XRD) spectroscopy are used to analyze the structure and electronic surface characteristics of the ZnO insulator. Capacitance-voltage (C-V) measurements are used to understand the …

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Influence Of Electron Trapping On Minority Carrier Transport Properties Of Wide Band Gap Semiconductors, Olena Tirpak Jan 2007

Influence Of Electron Trapping On Minority Carrier Transport Properties Of Wide Band Gap Semiconductors, Olena Tirpak

Electronic Theses and Dissertations

Minority carrier transport properties and the effects of electron irradiation/injection were studied in GaN and ZnO containing dopants known to form acceptor states deep within the materials' bandgap. Minority carrier diffusion length and lifetime changes were investigated using Electron Beam Induced Current (EBIC) method, cathodoluminescence spectroscopy, spectral photoresponse and persistent photoconductivity measurements. It is shown that electron irradiation by the beam of a scanning electron microscope results in a significant increase of minority carrier diffusion length. These findings are supported by the cathodoluminescence measurements that demonstrate the decay of near-band-edge intensity as a consequence of increasing carrier lifetime under continuous …

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Hybrid Photonic Signal Processing, Farzan Naseer Ghauri Jan 2007

Hybrid Photonic Signal Processing, Farzan Naseer Ghauri

Electronic Theses and Dissertations

This thesis proposes research of novel hybrid photonic signal processing systems in the areas of optical communications, test and measurement, RF signal processing and extreme environment optical sensors. It will be shown that use of innovative hybrid techniques allows design of photonic signal processing systems with superior performance parameters and enhanced capabilities. These applications can be divided into domains of analog-digital hybrid signal processing applications and free-space--fiber-coupled hybrid optical sensors. The analog-digital hybrid signal processing applications include a high-performance analog-digital hybrid MEMS variable optical attenuator that can simultaneously provide high dynamic range as well as high resolution attenuation controls; an …

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Rigorous Analysis Of Wave Guiding And Diffractive Integrated Optical Structures, Andrew Greenwell Jan 2007

Rigorous Analysis Of Wave Guiding And Diffractive Integrated Optical Structures, Andrew Greenwell

Electronic Theses and Dissertations

The realization of wavelength scale and sub-wavelength scale fabrication of integrated optical devices has led to a concurrent need for computational design tools that can accurately model electromagnetic phenomena on these length scales. This dissertation describes the physical, analytical, numerical, and software developments utilized for practical implementation of two particular frequency domain design tools: the modal method for multilayer waveguides and one-dimensional lamellar gratings and the Rigorous Coupled Wave Analysis (RCWA) for 1D, 2D, and 3D periodic optical structures and integrated optical devices. These design tools, including some novel numerical and programming extensions developed during the course of this work, …

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An Examination Of The Effectiveness Of The Adomian Decomposition Method In Fluid Dynamic Applications, Sonia Holmquist Jan 2007

An Examination Of The Effectiveness Of The Adomian Decomposition Method In Fluid Dynamic Applications, Sonia Holmquist

Electronic Theses and Dissertations

Since its introduction in the 1980's, the Adomian Decomposition Method (ADM) has proven to be an efficient and reliable method for solving many types of problems. Originally developed to solve nonlinear functional equations, the ADM has since been used for a wide range of equation types (like boundary value problems, integral equations, equations arising in flow of incompressible and compressible fluids etc...). This work is devoted to an evaluation of the effectiveness of this method when used for fluid dynamic applications. In particular, the ADM has been applied to the Blasius equation, the Falkner-Skan equation, and the Orr-Sommerfeld equation. This …

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Towards A Self-Calibrating Video Camera Network For Content Analysis And Forensics, Imran Junejo Jan 2007

Towards A Self-Calibrating Video Camera Network For Content Analysis And Forensics, Imran Junejo

Electronic Theses and Dissertations

Due to growing security concerns, video surveillance and monitoring has received an immense attention from both federal agencies and private firms. The main concern is that a single camera, even if allowed to rotate or translate, is not sufficient to cover a large area for video surveillance. A more general solution with wide range of applications is to allow the deployed cameras to have a non-overlapping field of view (FoV) and to, if possible, allow these cameras to move freely in 3D space. This thesis addresses the issue of how cameras in such a network can be calibrated and how …

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Efficient Inversion Of The Cone Beam Transform For A General Class Of Curves, Mikhail Kapralov Jan 2007

Efficient Inversion Of The Cone Beam Transform For A General Class Of Curves, Mikhail Kapralov

Electronic Theses and Dissertations

We extend an efficient cone beam transform inversion formula, proposed earlier for helices, to a general class of curves. The conditions that describe the class are very natural. Curves C are smooth, without self-intersections, have positive curvature and torsion, do not bend too much in a certain sense, and do not admit lines which are tangent to C at one point and intersect C at another point. A domain U is found where reconstruction is possible with a filtered backprojection type algorithm. Results of numerical experiments demonstrate very good image quality. The algorithm developed is useful for image reconstruction in …

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Pade Approximants And One Of Its Applications, Tame-Kouontcho Fowe Jan 2007

Pade Approximants And One Of Its Applications, Tame-Kouontcho Fowe

Electronic Theses and Dissertations

This thesis is concerned with a brief summary of the theory of Pade approximants and one of its applications to Finance. Proofs of most of the theorems are omitted and many developments could not be mentioned due to the vastness of the field of Pade approximations. We provide reference to research papers and books that contain exhaustive treatment of the subject. This thesis is mainly divided into two parts. In the first part we derive a general expression of the Pade approximants and some of the results that will be related to the work on the second part of the …

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High Birefringence Liquid Crystals For Optical Communications, Amanda Jane Parish Jan 2007

High Birefringence Liquid Crystals For Optical Communications, Amanda Jane Parish

Electronic Theses and Dissertations

High birefringence (Δn > 0.4) nematic liquid crystals are particularly attractive for infrared applications because they enable a thinner cell gap to be used for achieving fast response time and improved diffraction efficiency. In this thesis, the mesomorphic and electro‐optic properties of several new fluorinated isothiocyanate (NCS) terphenyl and phenyl tolane single compounds and mixtures are reported. The single compounds demonstrated Δn~0.35‐0.52 in the visible spectral region at room temperature and exhibit relatively low viscosity. It was found that lateral fluorine substitutions and short alkyl chains eliminate smectic phase and lower the melting temperature of the single compounds. However, the consequence …

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Forensic Analysis Of C-4 And Commercial Blasting Agents For Possible Discrimination, Katie Steele Jan 2007

Forensic Analysis Of C-4 And Commercial Blasting Agents For Possible Discrimination, Katie Steele

Electronic Theses and Dissertations

The criminal use of explosives has increased in recent years. Political instability and the wide spread access to the internet, filled with "homemade recipes," are two conjectures for the increase. C-4 is a plastic bonded explosive (PBX) comprised of 91% of the high explosive RDX, 1.6% processing oils, 5.3% plasticizer, and 2.1% polyisobutylene (PIB). C-4 is most commonly used for military purposes, but also has found use in commercial industry as well. Current methods for the forensic analysis of C-4 are limited to identification of the explosive; however, recent publications have suggested the plausibility of discrimination between C-4 samples based …

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Stability And Preservation Properties Of Multisymplectic Integrators, Tomasz Wlodarczyk Jan 2007

Stability And Preservation Properties Of Multisymplectic Integrators, Tomasz Wlodarczyk

Electronic Theses and Dissertations

This dissertation presents results of the study on symplectic and multisymplectic numerical methods for solving linear and nonlinear Hamiltonian wave equations. The emphasis is put on the second order space and time discretizations of the linear wave, the Klein-Gordon and the sine-Gordon equations. For those equations we develop two multisymplectic (MS) integrators and compare their performance to other popular symplectic and non-symplectic numerical methods. Tools used in the linear analysis are related to the Fourier transform and consist of the dispersion relationship and the power spectrum of the numerical solution. Nonlinear analysis, in turn, is closely connected to the temporal …

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Modulational Instability In Nonlinearity-Managed Optical Media, Martin Centurion, Mason A. Porter, Ye Pu, P. G. Kevrekidis, D. J. Frantzeskakis, Demetri Psaltis Jan 2007

Modulational Instability In Nonlinearity-Managed Optical Media, Martin Centurion, Mason A. Porter, Ye Pu, P. G. Kevrekidis, D. J. Frantzeskakis, Demetri Psaltis

Martin Centurion Publications

We investigate analytically, numerically, and experimentally the modulational instability in a layered, cubically nonlinear (Kerr) optical medium that consists of alternating layers of glass and air. We model this setting using a nonlinear Schrödinger (NLS) equation with a piecewise constant nonlinearity coefficient and conduct a theoretical analysis of its linear stability, obtaining a Kronig-Penney equation whose forbidden bands correspond to the modulationally unstable regimes. We find very good quantitative agreement between the theoretical analysis of the Kronig-Penney equation, numerical simulations of the NLS equation, and the experimental results for the modulational instability. Because of the periodicity in the evolution variable …

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Magnetism Of Fe Clusters Formed By Buffer-Layer Assisted Growth On Pt(997), J. Zhang, D. Repetto, V. Sessi, Jan Honolka, Axel Enders, Klaus Kern Jan 2007

Magnetism Of Fe Clusters Formed By Buffer-Layer Assisted Growth On Pt(997), J. Zhang, D. Repetto, V. Sessi, Jan Honolka, Axel Enders, Klaus Kern

Axel Enders Publications

The growth and magnetism of nanometer size Fe clusters on stepped Pt surfaces is investigated by scanning tunneling microscopy (STM) and magneto-optical Kerr effect measurements (MOKE). The clusters are formed on xenon buffer layers of varying thickness and then brought into contact with the substrate by thermal desorption of the Xe. The cluster size is controlled by the thickness of the Xe layer. It is found that clusters of diameter smaller than the Pt terrace width of 2 nm are aligned along the step edges of the Pt(997), thus forming linear cluster chains. In this arrangement, the clusters are ferromagnetic …

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Magnetic Anisotropy Of Deposited Transition Metal Clusters, S. Bornemann, J. Minar, J.B. Staunton, Jan Honolka, Axel Enders, Hubert Ebert Jan 2007

Magnetic Anisotropy Of Deposited Transition Metal Clusters, S. Bornemann, J. Minar, J.B. Staunton, Jan Honolka, Axel Enders, Hubert Ebert

Axel Enders Publications

We present results of magnetic torque calculations using the fully relativistic spin-polarized Korringa-Kohn-Rostoker approach applied to small Co and Fe clusters deposited on the Pt(111) surface. From the magnetic torque one can derive amongst others the magnetic anisotropy energy (MAE). It was found that this approach is numerically much more stable and also computationally less demanding than using the magnetic force theorem that allows to calculate the MAE directly. Although structural relaxation effects were not included our results correspond reasonably well to recent experimental data.

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Importance Of Verification And Validation Of Data Sources In Attaining Information Superiority, Gautham Kasinath, Leisa J. Armstrong Jan 2007

Importance Of Verification And Validation Of Data Sources In Attaining Information Superiority, Gautham Kasinath, Leisa J. Armstrong

Research outputs pre 2011

Information superiority has been defined as a state that is achieved when a competitive advantage is derived from the ability to exploit a superior information position. To achieve such a superior information position enterprises and nations, alike, must not only collect and record correct, accurate, timely and useful information but also ensure that information recorded is not lost to competitors due to lack of comprehensive security and leaks. Further, enterprises that aim to attain information superiority must also ensure mechanisms of validating and verifying information to reduce the chances of mis-information. Although, research has been carried out into ways to …

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Heat Shock Protein 90: A Potential Therapeutic Target In Leukemic Progenitor And Stem Cells Harboring Mutant Bcr-Abl Resistant To Kinase Inhibitors, C Peng, Dongguang Li, L Shaoguang Jan 2007

Heat Shock Protein 90: A Potential Therapeutic Target In Leukemic Progenitor And Stem Cells Harboring Mutant Bcr-Abl Resistant To Kinase Inhibitors, C Peng, Dongguang Li, L Shaoguang

Research outputs pre 2011

Development of drug resistance has become a major obstacle for tyrosine kinase inhibitors (TKIs) in the treatment of Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia (CML) and other cancers. The BCR-ABL-T315I mutant does not respond to clinically available TKIs, although some newly developed anti-BCR-ABL-T315I TKIs are now being tested in patients. TKIs transiently inhibit kinase activity of BCR-ABL, but do not reduce the level of the BCR-ABL protein. Elimination of mutant BCR-ABL protein would provide a new therapeutic strategy for treating Ph+ leukemia. We recently showed that inhibition of heat shock protein 90 (Hsp90) by a novel Hsp90 inhibitor, IPI-504, causes …

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Analysis Of Pki As A Means Of Securing Odf Documents, Gautham Kasinath, Leisa J. Armstrong Jan 2007

Analysis Of Pki As A Means Of Securing Odf Documents, Gautham Kasinath, Leisa J. Armstrong

Research outputs pre 2011

Public Key Infrastructure (PKI) has for the last two decades been a means of securing systems and communication. With the adoption of Open Document Format (ODF) as an ISO standard, the question remains if the unpopular, expensive, complex and unmaintainable PKI can prove to be a viable means of securing ODF documents. This paper analyses the drawbacks of PKI and evaluates the useji.tlness of PKl in provisioning robust, cheap and maintainable XML security to XML based ODF. This paper also evaluates the existing research on XML security, more specifically fine grained access control.

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Evolving Players For An Ancient Game: Hnefatafl, Philip Hingston Jan 2007

Evolving Players For An Ancient Game: Hnefatafl, Philip Hingston

Research outputs pre 2011

Hnefatafl is an ancient Norse game - an ancestor of chess. In this paper, we report on the development of computer players for this game. In the spirit of Blondie24, we evolve neural networks as board evaluation functions for different versions of the game. An unusual aspect of this game is that there is no general agreement on the rules: it is no longer much played, and game historians attempt to infer the rules from scraps of historical texts, with ambiguities often resolved on gut feeling as to what the rules must have been in order to achieve a balanced …

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Use Of Online Tools To Aid Group Work, Martin Masek Jan 2007

Use Of Online Tools To Aid Group Work, Martin Masek

Research outputs pre 2011

In this paper we examine the use of online tools – namely wikis and blogs in aiding group work for a large and diverse student-based team. The results suggest that while students see the generic skill of being able to work in a team as important for their future career, using blogs and wikis is not seen to be as important. It was also found that the flexibility of these tools provides more motivation for students than having assessment based on their use.

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Australian Firearm Identification System Based On The Ballistics Images Of Projectile Specimens, Dongguang Li Jan 2007

Australian Firearm Identification System Based On The Ballistics Images Of Projectile Specimens, Dongguang Li

Research outputs pre 2011

Charactetistic markings on the cartridge case and projectile of a fired bullet are created when it is fired. Over thirty different features within these marks can be distinguished, which in combination produce a "fingerprint" for a firearm. By analyzing features within such a set of fireann :fingerprints, it will be possible to identify not only the type and model of a fireann, but also each every individual weapon as effectively as human :fingerprint identification. A new analytic system based on fast Fourier transform (FFT) for identifying the projectile specimens by the line-scan imaging technique is proposed in this paper. Experimental …

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Proceedings Of The Sixth International Workshop For Applied Pkc (Iwap2007), Dongguang Li Jan 2007

Proceedings Of The Sixth International Workshop For Applied Pkc (Iwap2007), Dongguang Li

Research outputs pre 2011

IWAP2007 will be the sixth of a series of successful international workshops with focus on research and engineering issues of the applied aspects of public key cryptosystems. The inaugural IWAP event was held in Korea in 2001, and was subsequently held in 2002, 2004, 2005 and 2006 respectively in Taipei, Japan, Singapore and China. The IWAP2003 was cancelled due to the SARS breakout. Theoreticians and practitioners interested in the applied issues of PKC were encouraged to participate and contribute to the continuous success of the IWAP workshop series. The host of the IWAP2007 is Edith Cowan University. It is my …

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Some Problems In Network And Data Centre Management, David Veal, Gurpreet Kohli Jan 2007

Some Problems In Network And Data Centre Management, David Veal, Gurpreet Kohli

Research outputs pre 2011

Computer networks are vital to the running of modern organisations. Network managers are often concerned with the running of data centres. This paper provides an overview of some of the more important issues in managing modern computer networks and data centres and the problems faced in undertaking this task. It would be impossible to provide a complete list which, due to the fluid nature of this industry, would become outdated very quickly. It is important that network managers have an awareness of modern Occupational Health and Safety (OHS) requirements, training and skills. There is also a need for network managers …

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Using A Cultural Lens To Interpret The Success And Failure Of Regional Internet Community Portals In Promoting E-Commerce Adoption By Smes, Denise Gengatharen, Craig Standing Jan 2007

Using A Cultural Lens To Interpret The Success And Failure Of Regional Internet Community Portals In Promoting E-Commerce Adoption By Smes, Denise Gengatharen, Craig Standing

Research outputs pre 2011

In Western Australia (WA), efforts to increase SME e-commerce adoption have been integrated with some governmentlunded collaboratively-owned regional Internet community portals. This paper examines three such cases, two in regional WA and one in the metropolitan area, to determine the impact of cultural factors on the success of these portals. Results indicate that the collectivist culture of the communities in the two regional areas played an important role in initially sustaining the portals. Subsequently, legitimacy and mimetic pressure also contributed to SME involvement in these portals resulting in an overall increase in awareness by this sector of the benefits and …

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Factors Influencing Speed Of Cancer Diagnosis In Rural Wa, Moyez Jiwa, Georgia Halkett, Samar Aoun, Hayley Arnet, Marthe Smith, Megan Pilkington, Cheryl Mcmullen Jan 2007

Factors Influencing Speed Of Cancer Diagnosis In Rural Wa, Moyez Jiwa, Georgia Halkett, Samar Aoun, Hayley Arnet, Marthe Smith, Megan Pilkington, Cheryl Mcmullen

Research outputs pre 2011

Introduction: The speed of diagnosis impacts on prognosis and survival in all types of cancer. In most cases survival and prognosis are significantly worse in rural and remote Australian populations who have less access to diagnostic and therapeutic services than metropolitan communities in this country. Research suggests that in general delays in diagnosis were a factor of misdiagnosis, the confounding effect of existing conditions and delayed or misleading investigation of symptoms. The aim of this study is to further explore the factors that impact on the speed of diagnosis in rural Western Australia with direct reference to General Practitioners (GPs) …

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It Sharps: Issues Relating To Securely Disposing Of Hard Disks From Medical Information Systems, Craig Valli Jan 2007

It Sharps: Issues Relating To Securely Disposing Of Hard Disks From Medical Information Systems, Craig Valli

Research outputs pre 2011

Organisations worldwide are failing to adequately erase data from hard disks before disposing of them. Recent studies have uncovered significant and highly confidential data from computer hard disks for sale in the second hand market using minimal foresic recovery techniques. Increasingly medical businesses are being required to use IT based systems to deliver or receive services. Also medical records are becoming electronic in nature and have significant secondary storage requirements. Given the increased use of IT in medical practice this paper examines the issues uncovered in the studies into recovery of remnant data from hard disks. The paper also explores …

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Experimental Demonstration Of A Dynamic 10gbit/S Wdm Header/Label Recognition Structure, Muhsen Aljada, Kamal Alameh, Byeong Ha Lee, Yong Tak Lee, Kiegon Im, Se-Jong Baik Jan 2007

Experimental Demonstration Of A Dynamic 10gbit/S Wdm Header/Label Recognition Structure, Muhsen Aljada, Kamal Alameh, Byeong Ha Lee, Yong Tak Lee, Kiegon Im, Se-Jong Baik

Research outputs pre 2011

In this paper, we experimentally demonstrate a dynamic wavelength-division-multiplexing (WDM) header/label recognition structure that processes on-the-fly WDM patterns. An opto-VLSI processor is used to dynamically generate digital phase holograms that control the wavelength components of the label/header to create digital wavelength profiles. An autocorrelation function of a high-peak is generated when a label bit pattern matches a digital wavelength profile. The main attractive feature of using an opto-VLSI processor is that the lookup table of matching digital wavelength profiles does not need modification when the data bit-rate is upgraded. The dynamic pattern recognition structure is experimentally demonstrated at 10 Gbit/s …

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Experimental Demonstration Of A Tunable Laser Using An Soa And An Opto-Vlsi Processor, Muhsen Aljada, Rong Zheng, Kamal Alameh, Yong Lee Jan 2007

Experimental Demonstration Of A Tunable Laser Using An Soa And An Opto-Vlsi Processor, Muhsen Aljada, Rong Zheng, Kamal Alameh, Yong Lee

Research outputs pre 2011

In this paper we propose and experimentally demonstrate a tunable laser structure cascading a semiconductor optical amplifier (SOA) that generates broadband amplified spontaneous emission and a reflective Opto-VLSI processor that dynamically reflects arbitrarily wavelengths and injects them back into the SOA, thus synthesizing an output signal of variable wavelength. The wavelength tunablility is performed using digital phase holograms uploaded on the Opto-VLSI processor. Experimental results demonstrate a tuning range from 1524nm to 1534nm, and show that the proposed tunable laser structure has a stable performance.

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Pervasive 2d Barcodes For Camera Phone Applications, Hiroko Kato, Keng T. Tan Jan 2007

Pervasive 2d Barcodes For Camera Phone Applications, Hiroko Kato, Keng T. Tan

Research outputs pre 2011

In a previous study, we evaluated six 2D barcodes using eight criteria for standardization potential: omnidirectional symbol reading, support for low-resolution cameras, reading robustness under different lighting conditions, barcode reading distance, error correction capability, security, support for multiple character sets, and data capacity. We also considered the fidelity of the camera phone's captured image as a metric for gauging reading reliability. Here, we review the six 2D barcodes and then use an additional metric - a first-read rate - to quantitatively verify our earlier results and better gauge reading reliability.

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It Devices And Energy Consumption, David Veal Jan 2007

It Devices And Energy Consumption, David Veal

Research outputs pre 2011

The need for energy conservation has been topical for many years and has gained importance with global warming scenarios and the increasing cost of energy. This paper examines energy consumption of common home IT devices such as routers, voice boxes, PCs and printers with respect to minimising standby power. Another problem of concern in energy usage as related to IT activity is the increasing electrical power consumption levels of data centres, along with data centre cooling problems and the attempts to enhance their energy efficiency. These scenarios illustrate small amounts of energy consumption used by vast numbers of device compared …

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Profiling Through A Digital Mobile Device, Lee Fueng Yap, Andrew Jones Jan 2007

Profiling Through A Digital Mobile Device, Lee Fueng Yap, Andrew Jones

Research outputs pre 2011

Mobile digital devices have evolved from telecommunications device to a lifestyle product over the years. These devices are used in all aspects of our daily life. As a result, more information is stored within the devices. Unprotected mobile digital device is susceptible to privacy invasion attack when the device falls into the wrong hand of any unscrupulous third party. The main objective of this paper is to provide an implication analysis on the possible risks of information leakage through digital mobile devices, in the case when users forget to, or choose never to apply any security protection to their devices

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