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Full-Text Articles in Social and Behavioral Sciences

Generic Construction Of Hybrid Public Key Traitor Tracing With Full-Public-Traceability, Duong Hieu Phan, Rei Safavi-Naini, Joseph Tonien Jan 2006

Generic Construction Of Hybrid Public Key Traitor Tracing With Full-Public-Traceability, Duong Hieu Phan, Rei Safavi-Naini, Joseph Tonien

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.


An Efficient Single-Key Pirates Tracing Scheme Using Cover-Free Families, Joseph Tonien, Rei Safavi-Naini Jan 2006

An Efficient Single-Key Pirates Tracing Scheme Using Cover-Free Families, Joseph Tonien, Rei Safavi-Naini

Faculty of Engineering and Information Sciences - Papers: Part A

A cover-free family is a well-studied combinatorial structure that has many applications in computer science and cryptography. In this paper, we propose a new public key traitor tracing scheme based on cover-free families. The new traitor tracing scheme is similar to the Boneh-Franklin scheme except that in the Boneh-Franklin scheme, decryption keys are derived from Reed-Solomon codes while in our case they are derived from a cover-free family. This results in much simpler and faster tracing algorithms for single-key pirate decoders, compared to the tracing algorithms of Boneh-Franklin scheme that use Berlekamp- Welch algorithm. Our tracing algorithms never accuse innocent ...


Distributed Generation Control Using Protection Principles, An D. T Le, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich Jan 2006

Distributed Generation Control Using Protection Principles, An D. T Le, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.


Distributed Generation Diversity Level For Optimal Investment Planning, An D. T Le, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich Jan 2006

Distributed Generation Diversity Level For Optimal Investment Planning, An D. T Le, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

The task of improving the supply quality and maintaining supply continuity during emergencies has become more feasible for a distribution company (DISCO), owing to new developments in Distributed Generation (DG) technologies. Even though the technical issues regarding DG interconnection to the main grid are of great importance and are being addressed by on-going research, it must be clearly placed in the context of on the financial performance of the utility. In this paper, a general approach to quantify the technical benefits of DG employment is proposed. The power system economic impact is assessed by evaluating supply quality, supply reliability, system ...


Control Stabilisation Of An Islanded System With Dfig Wind Turbine, M Aktarujjaman, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich Jan 2006

Control Stabilisation Of An Islanded System With Dfig Wind Turbine, M Aktarujjaman, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

Distributed Generation (DG) is often used to export power to the utility system. Loss of main supply can cause a severe loading mismatch between DG generation and load consumption. Consequently, the voltage and frequency of the islanded system will cross the allowable limit. Due to this fact, it is essential to control the voltage and frequency in the islanding mode of operation. In this paper, control stabilisation of an islanded system with a doubly-fed induction generator (DFIG) wind turbine has been addressed. Wind DG produces variable output and is not capable to produce enough reactive power. Hence, it is imperative ...


Energy Storage System For Reduction Of Mid-Line Voltage Variation Of A Dfig Wnd Turbine Connected To A Weak Grid, M Aktarujjaman, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich Jan 2006

Energy Storage System For Reduction Of Mid-Line Voltage Variation Of A Dfig Wnd Turbine Connected To A Weak Grid, M Aktarujjaman, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

Penetration of wind power into electricity system is constantly increasing. Wind resources are usually distant from existing transmission lines. Wind farms are often connected to weak grids far from central generation stations. Maximum wind power extraction causes the more irregular and unpredicted power output of wind turbine, which has same nature as wind speed variation. The voltage in such long line is vulnerable with the consumption and generation imbalance. In a long line, the mid-line voltage is largely affected by the variation and the penetration of the wind fluctuating power. Fluctuating nature of wind power output and long transmission line ...


Hydro-Turbine Governor Control: Theory, Techniques And Limitations, J Culberg, Michael Negnevitsky, Kashem M. Muttaqi Jan 2006

Hydro-Turbine Governor Control: Theory, Techniques And Limitations, J Culberg, Michael Negnevitsky, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

With the entry of Tasmania into the national electricity market, equipment upgrades are required in many parts of the existing power system. This presents an opportunity to embrace new technology, in order to enhance the current efficiency and productivity of the system. One area is that of hydro-turbine speed governors, an integral part of maintaining the frequency of the output. This paper analyses the current standard control algorithm for turbine governors, the PID controller. It illustrates the processes involved, tuning and their limitations. Finally, alternative control systems are discussed.


Black Start With Dfig Based Distributed Generation After Major Emergencies, M Aktarujjaman, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich Jan 2006

Black Start With Dfig Based Distributed Generation After Major Emergencies, M Aktarujjaman, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

Grid connected distributed generation (DG) increases reliability and additional benefits for consumers as well as utilities. The stable and reliable operation of a power system is necessary after major emergencies (or blackouts) following a major system event. Distributed generation may be capable of black start and contribute to fast restoration process at medium to low voltage level. A large scale voltage and frequency excursions may occur during the process of black start with distributed generation due to low inertia and intermittency in power generation. Energy storage integrated with DG can absorb initial impact of central generation and ensure smooth load ...


Control Strategy Of Distributed Generation For Voltage Support In Distribution Systems, An D. T Le, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich Jan 2006

Control Strategy Of Distributed Generation For Voltage Support In Distribution Systems, An D. T Le, Kashem M. Muttaqi, Michael Negnevitsky, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

Voltage problem is always a critical issue in operating a distribution system. The uncertainties of load distribution and variation have introduced a great complexity to the task of maintaining system voltage within the permitted range. In this paper, small-scale generator, known as distributed generation (DG), is employed in the system and acting as a voltage regulator. The output of DG is controlled in such a way that acceptable level of electrical supply quality is achieved with a reasonable operating cost. The DG controller is tested with a non-uniformly varying load on the time domain basis. Simulations have been conducted with ...


Loading Capabilities Assesment Of Power Transmission Lines, P Hu, Michael Negnevitsky, Kashem M. Muttaqi Jan 2006

Loading Capabilities Assesment Of Power Transmission Lines, P Hu, Michael Negnevitsky, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

This paper reviews the factors that affect the loading capabilities of the transmission line over the short duration. The paper demonstrates how to determine the impact of various parameters on the permissible loading of bare conductors of a power transmission line. Methods for calculating these factors are presented. A sample of a practical application is also included in order to show how these factors affect the loading capabilities of a transmission line.


Distributed Generation For Minimization Of Power Losses In Distribution Systems, Kashem M. Muttaqi, An D. T Le, Michael Negnevitsky, Gerard Ledwich Jan 2006

Distributed Generation For Minimization Of Power Losses In Distribution Systems, Kashem M. Muttaqi, An D. T Le, Michael Negnevitsky, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

Appropriate size and location of distributed generation (DG) play a significant role in minimizing power losses in distribution systems. This paper represents techniques to minimize power losses in a distribution feeder by optimizing DG model in terms of size, location and operating point of DG. Sensitivity analysis for power losses in terms of DG size and DG operating point has been performed. The proposed sensitivity indices can indicate the changes in power losses with respect to DG current injection. The proposed techniques have been developed with considering load characteristics and representing loads with constant impedance and constant current models, separately ...


Spatial Prediction For Massive Datasets, Noel A. Cressie, Gardar Johannesson Jan 2006

Spatial Prediction For Massive Datasets, Noel A. Cressie, Gardar Johannesson

Faculty of Engineering and Information Sciences - Papers: Part A

Remotely sensed spatio-temporal datasets on the order of megabytes to terrabytes are becoming more common. For example, polar-orbiting satellites observe Earth from space, monitoring the Earth's atmospheric, oceanic, and terrestrial processes, and generate massive amounts of environmental data. The current generation of satellites, such as the National Aeronautic and Space Administration's (NASA) Earth Observing System (EOS) Terra and Aqua satellites, generate about 1.5 terrabytes of data per day. In the USA, there are remote-sensing projects in preparation that will dwarf even these datasets. NASA, the National Oceanic and Atmospheric Administration (NOAA), and the Department of Defense (DoD ...


Gait Analysis Of Low-Cost Flexible-Shank Transtibial Prostheses, Winson Lee, Ming Zhang, Peggy Chan, David A. Boone Jan 2006

Gait Analysis Of Low-Cost Flexible-Shank Transtibial Prostheses, Winson Lee, Ming Zhang, Peggy Chan, David A. Boone

Faculty of Engineering and Information Sciences - Papers: Part A

The latest lower-limb prosthetic designs have been incorporated with dynamic elastic response (DER) components to enhance prosthesis flexibility, which are suggested to be beneficial to gait. Although DER prosthetic. feet are preferred by most transtibial amputees and their benefits to gait are supported by some biomechanical studies, many are still utilizing the simple conventional solid ankle cushioned heel (SACH) designs because of the lower cost. The monolimb, a transtibial prosthesis with the socket and the shank molded from a single piece of thermoplastic material, perhaps is an alternative to DER feet for providing flexibility at the shank. In addition to ...


A Numerical Approach To Evaluate The Fatigue Life Of Monolimb, Nian-Zhong Chen, Winson Lee, Ming Zhang Jan 2006

A Numerical Approach To Evaluate The Fatigue Life Of Monolimb, Nian-Zhong Chen, Winson Lee, Ming Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

Monolimb refers to a transtibial prosthesis with the prosthetic socket and the shank being molded into one piece of thermoplastic material. Shank flexibility of a monolimb can improve gait and comfort. However, fatigue failure of monolimbs under cyclic walking load is an important concern. This study is to evaluate the fatigue life of a monolimb designed for a transtibial amputee, based on finite element analysis, the statistical Miner's rule and reliability analysis. Stress uncertainty due to modeling error and the scatter in fatigue test data were considered. Results indicated that the accuracy of fatigue life evaluation of monolimb depends ...


Quantifying The Regional Load-Bearing Ability Of Trans-Tibial Stumps, Ming Zhang, Winson Lee Jan 2006

Quantifying The Regional Load-Bearing Ability Of Trans-Tibial Stumps, Ming Zhang, Winson Lee

Faculty of Engineering and Information Sciences - Papers: Part A

This paper reports findings of experiments aiming to (1) compare the load tolerant ability over different regions of stumps of lower limb amputees, (2) study the effect of walking on the load tolerant ability, and (3) examine the distal-end weight-bearing ability supported by different interface materials. The method was to apply increasing load to the stump up to the pain level through a force transducer or a digital scale, considering the effect of regional difference, walking, and interface materials. The results show that the patellar tendon and the distal end of the fibula were the best and worst load-tolerant region ...


A Robust Design Procedure For Improvement Of Quality Of Lower-Limb Prosthesis, Nian-Zhong Chen, Winson Lee, Ming Zhang Jan 2006

A Robust Design Procedure For Improvement Of Quality Of Lower-Limb Prosthesis, Nian-Zhong Chen, Winson Lee, Ming Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

Lower-limb prostheses are used to restore amputee's walking. Monolimb is one of the designs referring to socket and the shank being molded into one piece of thermoplastic material. Appropriate shank flexibility of a monolimb can improve gait of an amputee. However, during the fabrication, the variations of design variables are inevitably produced which may lead the unexpected shank deflection and directly influence on gait efficiency of an amputee. This paper presents a robust design procedure for improvement of quality of the monolimb by simultaneously minimizing performance variations caused by variations in design variables and bringing the mean value of ...


Jacket Matrices Constructed From Hadamard Matrices And Generalized Hadamard Matrices, Ken Finlayson, Moon Ho Lee, Jennifer Seberry, Mieko Yamada Jan 2006

Jacket Matrices Constructed From Hadamard Matrices And Generalized Hadamard Matrices, Ken Finlayson, Moon Ho Lee, Jennifer Seberry, Mieko Yamada

Faculty of Engineering and Information Sciences - Papers: Part A

Jacket matrices constructed from Hadamard matrices and generalized Hadamard matrices.


The Use Of Maple Platform For The Study Of Geodisc Motion On Curved Spacetimes, Dumitru N. Vulcanov, Valentina D. Wheeler Jan 2006

The Use Of Maple Platform For The Study Of Geodisc Motion On Curved Spacetimes, Dumitru N. Vulcanov, Valentina D. Wheeler

Faculty of Engineering and Information Sciences - Papers: Part A

The article illustrates the graphical study of geodesic motion on curved space-times (mainly exact solutions of Einstein equations) using the symbolic, numerical and graphical computation facilities of Maple platform. The example of null geodesics on Schwarzschild solution is completely processed. The geodesic curves are plotted directly using DEtools package in Schwarzschild coordinates.


Exel's Crossed Product And Relative Cuntz-Pimsner Algebras, Nathan Brownlowe, Iain Raeburn Jan 2006

Exel's Crossed Product And Relative Cuntz-Pimsner Algebras, Nathan Brownlowe, Iain Raeburn

Faculty of Engineering and Information Sciences - Papers: Part A

We consider Exel's new construction of a crossed product of a $C^*$-algebra $A$ by an endomorphism $\alpha$. We prove that this crossed product is universal for an appropriate family of covariant representations, and we show that it can be realised as a relative Cuntz-Pimsner algbera. We describe a necessary and sufficient condition for the canonical map from $A$ into the crossed product to be injective, and present several examples to demonstrate the scope of this result. We also prove a gauge-invariant uniqueness theorem for the crossed product.


The Effect Of Small Business Clusters In Prioritising Barriers To E-Commerce Adoption In Regional Smes, Robert Macgregor, Lejla Vrazalic Jan 2006

The Effect Of Small Business Clusters In Prioritising Barriers To E-Commerce Adoption In Regional Smes, Robert Macgregor, Lejla Vrazalic

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a study of Swedish regional small businesses which investigated the barriers to E-commerce adoption (amongst other things). The aim of the paper is twofold: to examine the correlation between barriers to E-commerce adoption in order to identify underlying factors: and to determine whether these differ between SMEs that are members of a small business cluster and SMEs that are not. The paper begins by examining the nature of SMEs and identifying features that are unique to SMEs. A discussion of barriers to E-commerce adoption based on previous research is then presented and the barriers are mapped to ...


Reply To Comment By M. Bayani Cardenas And John L. Wilson On "Flow Resistance And Bed Form Geometry In A Wide Alluvial Channel", Shu-Qing Yang, Soon-Keat Tan, Siow-Yong Lim Jan 2006

Reply To Comment By M. Bayani Cardenas And John L. Wilson On "Flow Resistance And Bed Form Geometry In A Wide Alluvial Channel", Shu-Qing Yang, Soon-Keat Tan, Siow-Yong Lim

Faculty of Engineering and Information Sciences - Papers: Part A

The authors would like to thank Cardenas and Wilson [2006] for their valuable comments and interesting discussions.


Chandra Observations Of Nuclear Outflows In The Elliptical Galaxy Ngc 4552 In The Virgo Cluster, M Machacek, Paul E. J Nulsen, C Jones, W R. Forman Jan 2006

Chandra Observations Of Nuclear Outflows In The Elliptical Galaxy Ngc 4552 In The Virgo Cluster, M Machacek, Paul E. J Nulsen, C Jones, W R. Forman

Faculty of Engineering and Information Sciences - Papers: Part A

We use a 54.4 ks Chandra observation to study nuclear outflow activity in NGC 4552 (M89), an elliptical galaxy in the Virgo Cluster. Chandra images in the 0.5–2 keV band show two ringlike features ∼1.7 kpc in diameter in the core of NGC 4552, as reported previously by Filho et al. We use spherically symmetric point explosion shock models to argue that the shape of the surface brightness profile across the rims of the rings and the temperature of hot gas in the rings are consistent with a Mach 1.7 shock carrying mean mechanical power ...


Large Amplitude Nematicon Propagation In A Liquid Crystal With Local Response, Catherine Garcia-Reimbert, Antonmaria Minzoni, Noel Smyth, Annette L. Worthy Jan 2006

Large Amplitude Nematicon Propagation In A Liquid Crystal With Local Response, Catherine Garcia-Reimbert, Antonmaria Minzoni, Noel Smyth, Annette L. Worthy

Faculty of Engineering and Information Sciences - Papers: Part A

The evolution of polarized light in a nematic liquid crystal whose directors have a local response to reorienta-tion by the light is analyzed for arbitrary input light power. Approximate equations describing this evolution are derived based on a suitable trial function in a Lagrangian formulation of the basic equations governing the electric fields involved. It is shown that the nonlinearity of the material response is responsible for the forma-tion of solitons, so-called nematicons, by saturating the nonlinearity of the governing nonlinear Schrödinger equation. Therefore in the local material response limit, solitons are formed due to the nonlinear saturation behavior. It ...


A Dual Graph Construction For Higher-Rank Graphs, And K-Theory For Finite 2-Graphs, Stephen Allen, David Pask, Aidan Sims Jan 2006

A Dual Graph Construction For Higher-Rank Graphs, And K-Theory For Finite 2-Graphs, Stephen Allen, David Pask, Aidan Sims

Faculty of Engineering and Information Sciences - Papers: Part A

Given a k-graph Λ and an element p of Nk, we define the dual k-graph, pΛ. We show that when Λ is row-finite and has no sources, the C*-algebras C*(Λ) and C*(pΛ) coincide. We use this isomorphism to apply Robertson and Steger's results to calculate the K-theory of C*(Λ) when Λ is finite and strongly connected and satisfies the aperiodicity condition.


Validation Of The Geant4 Bremsstrahlung Models: First Results, S Chauvie, S Guatelli, B Mascialino, L Pandola, M G. Pia, P Rodrigues, A Trindade Jan 2006

Validation Of The Geant4 Bremsstrahlung Models: First Results, S Chauvie, S Guatelli, B Mascialino, L Pandola, M G. Pia, P Rodrigues, A Trindade

Faculty of Engineering and Information Sciences - Papers: Part A

A project is in progress for a systematic, rigorous validation of Geant4 electromagnetic physics. This paper presents the first results concerning the validation of Geant4 bremsstrahlung models against experimental data.


Geant4 Simulation For Lhc Radiation Monitoring, M Glaser, S Guatelli, B Mascialino, M Moll, M G. Pia, F Ravotti Jan 2006

Geant4 Simulation For Lhc Radiation Monitoring, M Glaser, S Guatelli, B Mascialino, M Moll, M G. Pia, F Ravotti

Faculty of Engineering and Information Sciences - Papers: Part A

Monitoring radiation background is a crucial task for the operation of LHC experiments. A project is in progress at CERN for the optimisation of the radiation monitors for LHC experiments. A simulation system based on Geant4, designed to assist the engineering optimisation of LHC radiation monitor detectors, is presented. Various detector packaging configurations are studied through their Geant4-based simulation, and their behaviour is compared.


Models Of Biological Effects Of Radiation In The Geant4 Toolkit, S Chauvie, Z Francis, S Guatelli, S Incerti, G Montarou, P Nieminen, M G. Pia Jan 2006

Models Of Biological Effects Of Radiation In The Geant4 Toolkit, S Chauvie, Z Francis, S Guatelli, S Incerti, G Montarou, P Nieminen, M G. Pia

Faculty of Engineering and Information Sciences - Papers: Part A

A project, named Geant4-DNA, is in progress to extend the Geant4 simulation toolkit to model the effects of radiation with biological systems at cellular and DNA level. The first component implemented in the first development cycle of the project describes the fractional survival of a population of cells irradiated with photons or charged particles. The software system developed provides the user the option to choose among a small set of alternative models for the calculation of mammalian cell survival after irradiation. The flexible design adopted makes the system open to further extension to implement other cell survival models available in ...


Geant4 Antropomorphic Phantoms, Susanna Guatelli, Barbara Mascialino, Maria Grazia Pia, Witold Pokorski Jan 2006

Geant4 Antropomorphic Phantoms, Susanna Guatelli, Barbara Mascialino, Maria Grazia Pia, Witold Pokorski

Faculty of Engineering and Information Sciences - Papers: Part A

A novel architectural approach to the design of human phantom software models is presented. A detailed design has been developed to enable the adoption of this approach in Geant4-based simulation applications. A few preliminary implementations and application demonstrations are described.


Validation Of Geant4 Electromagnetic And Hadronic Models Against Proton Data, G A. P Cirrone, G Cuttone, F Di Rosa, S Guatelli, B Mascialino, M G. Pia, G Russo Jan 2006

Validation Of Geant4 Electromagnetic And Hadronic Models Against Proton Data, G A. P Cirrone, G Cuttone, F Di Rosa, S Guatelli, B Mascialino, M G. Pia, G Russo

Faculty of Engineering and Information Sciences - Papers: Part A

A comprehensive, rigorous validation of Geant4 electromagnetic and hadronic models pertinent to the simulation of the proton Bragg peak in water is presented. Geant4 simulation results are validated against high precision experimental data taken in the CATANA hadrontherapy facility.


Geant4 Simulation In A Distributed Computing Environment, Susanna Guatelli, Alfonso Mantero, Patricia Mendez Lorenzo, Jakub Moscicki, Maria Grazia Pia Jan 2006

Geant4 Simulation In A Distributed Computing Environment, Susanna Guatelli, Alfonso Mantero, Patricia Mendez Lorenzo, Jakub Moscicki, Maria Grazia Pia

Faculty of Engineering and Information Sciences - Papers: Part A

A general system to perform a Geant4-based simulation in a distributed computing environment is presented. The architecture developed makes the system transparent to sequential or parallel execution and to the environment where the simulation is run: a single machine, a local cluster or a geographically distributed grid.