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Faculty of Informatics - Papers (Archive)

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Articles 1021 - 1050 of 2013

Full-Text Articles in Physical Sciences and Mathematics

Performance Comparison Of Uwb Hopping Codes In A Multi-User Rich Scattering Environment, K. Popovski, Beata J. Wysocki, Tadeusz A. Wysocki May 2006

Performance Comparison Of Uwb Hopping Codes In A Multi-User Rich Scattering Environment, K. Popovski, Beata J. Wysocki, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

Ultra Wideband is a short-range wireless communication technique which has seen increased interest over the past decade. Having several methods of implementation, a key issue will always be the avoidance of multi-user interference. For time-hopped Ultra Wideband, this is achieved through the use of different codes assigned to each user, performing time-hopped code division multiple access. This paper presents a performance comparison of several time hopping sequence construction methods. It presents correlation results between sequences, and simulation results in a Gaussian noise degraded, scattering rich multi-user environment. Simulations are based on the IEEE channel model for UWB communications.

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Identification Of Load Power Quality Characteristics Using Data Mining, Ali Asheibi, David A. Stirling, Duane Robinson May 2006

Identification Of Load Power Quality Characteristics Using Data Mining, Ali Asheibi, David A. Stirling, Duane Robinson

Faculty of Informatics - Papers (Archive)

The rapid increase in computer technology and the availability of large scale power quality monitoring data should now motivate distribution network service providers to attempt to extract information that may otherwise remain hidden within the recorded data. Such information may be critical for identification and diagnoses of power quality disturbance problems, prediction of system abnormalities or failure, and alarming of critical system situations. Data mining tools are an obvious candidate for assisting in such analysis of large scale power quality monitoring data. This paper describes a method of applying unsupervised and supervised learning strategies of data mining in power quality …

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Undular Bore Solution Of The Camassa-Holm Equation, Timothy R. Marchant, N. F. Smyth May 2006

Undular Bore Solution Of The Camassa-Holm Equation, Timothy R. Marchant, N. F. Smyth

Faculty of Informatics - Papers (Archive)

Modulation theory is developed for a periodic peakon solution of the Camassa-Holm equation. An explicit simple wave solution of these modulation equations is then derived; this simple wave describing the evolution into an undular bore of an initial step. The characteristic on which the expansion fan occurs (propagating at a nonlinear group velocity) has a turning point, illustrating the fact that there is a minimum nonlinear group velocity at which the waves can propagate. A linear analytical solution, based on an integral of the Airy function, is then derived to describe the evanescent portion of the undular bore behind the …

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A New Technique For Reducing Mac Address Overheads In Sensor Networks, Kwan-Wu Chin, Darryn Lowe, Ricardo Gandia Sanchez May 2006

A New Technique For Reducing Mac Address Overheads In Sensor Networks, Kwan-Wu Chin, Darryn Lowe, Ricardo Gandia Sanchez

Faculty of Informatics - Papers (Archive)

In sensor networks, the size of the medium access control (MAC) address is prohibitively expensive when one considers the small payload and the cost of transmitting one bit. We address this problem by proposing a technique that encodes L-bits of the payload with a key derived from MAC addresses. We show how the decoding process removes the need for MAC addresses in packets.

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The Proliferation Of Identification Techniques For Citizens Throughout The Ages, Katina Michael, M G. Michael May 2006

The Proliferation Of Identification Techniques For Citizens Throughout The Ages, Katina Michael, M G. Michael

Faculty of Informatics - Papers (Archive)

Manual identification techniques date back to ancient times, however the need to identify individuals has heightened particularly since the Industrial Revolution. This paper traces the use of identification techniques throughout the ages and focuses on the growing importance of citizen identification (ID) by governments. The paper uses a historical approach beginning with manual techniques such as tattoos, through to more recent automatic identification (auto-ID) techniques such as smart cards and biometrics. Data was collected primarily through qualitative document analysis, and the paper contains thick description typical of a narrative. The findings indicate that identification techniques born for one purpose have …

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Towards Autonomous Service Level Agreement Negotiation For Adaptive Service Composition, Jun Yan, J. Zhang, J. Lin, M. B. Chhetri, S. K. Goh, R. Kowalczyk May 2006

Towards Autonomous Service Level Agreement Negotiation For Adaptive Service Composition, Jun Yan, J. Zhang, J. Lin, M. B. Chhetri, S. K. Goh, R. Kowalczyk

Faculty of Informatics - Papers (Archive)

This paper reports innovative research aiming at supporting autonomous establishment and maintenance of service level agreements in order to guarantee end-to-end quality of service requirements for service composition provision. In this research, a set of interrelated service level agreements is established and maintained for a service composition, through autonomous agent negotiation. To enable this, an innovative framework is proposed in which agents on behalf of the service requestor and the service providers can negotiate service level agreements in a coordinated way. This framework also enables adaptive service level agreement re-negotiation in the dynamic and ever-changing service environment.

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Exploiting Time Diversity To Improve Block Spread Ofdm In A Multipath Environment, Ibrahim S. Raad, Xiaojing Huang Apr 2006

Exploiting Time Diversity To Improve Block Spread Ofdm In A Multipath Environment, Ibrahim S. Raad, Xiaojing Huang

Faculty of Informatics - Papers (Archive)

This paper presents a new method to improve on block spread OFDM by exploiting time diversity to ensure that the blocks are independent and uncorrelated in a multipath environment. While BSOFDM utilizes frequency diversity to significantly improve on OFDM in frequency selective channel, this did not improve during flat fading channel which does occur during transmission. Our work has also shown that this improvement is also true in multipath transmission. By exploiting time and frequency diversity, BSOFDM is improved significantly over conventional BSOFDM and conventional OFDM.

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A Variable Length Linear Array For Smart Antenna Systems, Walid Raad, Ian S. Burnett, Ibrahim Raad Apr 2006

A Variable Length Linear Array For Smart Antenna Systems, Walid Raad, Ian S. Burnett, Ibrahim Raad

Faculty of Informatics - Papers (Archive)

Adaptive Arrays have been used extensively in wireless communications applications to reduce interference between desired users and interfering signals. In particular a large concentration of research has been directed to the Uniform Linear Array (ULA). However in most situations presented the authors utilise a fixed array length. In a mobile environment this has the disadvantage of producing a fixed beamwidth due to the fixed array length. This paper proposes an algorithm which can be used to determine the required beamwidth for a number of incoming signals by altering the length a specified number of elements present in an antenna array. …

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Certificateless Designated Verifier Signature Schemes, Xinyi Huang, Willy Susilo, Yi Mu, Futai Zhang Apr 2006

Certificateless Designated Verifier Signature Schemes, Xinyi Huang, Willy Susilo, Yi Mu, Futai Zhang

Faculty of Informatics - Papers (Archive)

Designated verifier signature schemes allow a signer to convince a designated verifier, in such a way that only the designated verifier will believe with the authenticity of such a signature. The previous constructions of designated verifier signature rely on the underlying Public Key Infrastructure, that requires both signer and verifier to verify the authenticity of the public keys, and hence, the certificates are required. In contrast to the previous constructions, in this paper, we propose the first notion and construction of the certificateless designated verifier signature scheme. In our new notion, the necessity of certificates are eliminated. We show that …

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Electric Field-Induced Force Between Two Identical Uncharged Spheres, B. J. Cox, N. Thamwattana, James M. Hill Apr 2006

Electric Field-Induced Force Between Two Identical Uncharged Spheres, B. J. Cox, N. Thamwattana, James M. Hill

Faculty of Informatics - Papers (Archive)

The problem of electric field-induced force between spheres is fundamental to electrorheological fluids. Previously published experimental results indicate that the interaction force between two spheres under an external field is not adequately explained by the existing approximate and numerical methods. The specific models compared were dipole, dipole with local field corrections and a finite-element analysis. This letter employs an exact solution (via the equivalent multipole-moment method) to the electrostatic problem which accurately predicts the low-frequency experimental results at all measured interstices. The solution presented later is self-contained and addresses specifically the geometry of the previously mentioned experimental results. While more …

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Swindew-S: Extending P2p Workflow Systems For Adaptive Composite Web Services, Jun Shen, Jun Yan, Yun Yang Apr 2006

Swindew-S: Extending P2p Workflow Systems For Adaptive Composite Web Services, Jun Shen, Jun Yan, Yun Yang

Faculty of Informatics - Papers (Archive)

SwinDeW, an innovative decentralised workflow management system, has established an underlying framework for peer-to-peer (p2p) based business process coordination environments. SwinDeW-S extends SwinDeW to support adaptive composite service orchestration in the era of service-oriented computing. This paper comprehensively presents features of SwinDeW-S, including the p2p network establishment, the messaging mechanism, the service deployment and enactment, the service discovery and advertisement, and the service flow execution. The prototypical extension of SwinDeW to SwinDeW-S and the advantages of SwinDeW-S are also examined and analysed. With the innovative integration of service and p2p-based enterprise application techniques, SwinDeW-S can support composite service orchestration, deployment …

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Simulation Of Hts Saturable Core-Type Fcls For Mv Distribution Systems, S B. Abbott, Duane Robinson, S Perera, F A. Darmann, C J. Hawley, T P. Beales Apr 2006

Simulation Of Hts Saturable Core-Type Fcls For Mv Distribution Systems, S B. Abbott, Duane Robinson, S Perera, F A. Darmann, C J. Hawley, T P. Beales

Faculty of Informatics - Papers (Archive)

The design principles and performance characteristics of a prototype high-temperature superconductor saturable magnetic core-type fault current limiter are described. These are based on a distribution network service provider feasibility specification that included the footprint and regulatory requirements for limiting fault currents. Time-domain simulations using PSCAD/EMTDC are given to illustrate specific applications and the transient behavior of the different distribution system configurations are investigated.

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Adaptive Resource Replication In A Ubiquitous Peertopeer Based Multimedia Distribution Environment, L. Rong, I. Burnett Jan 2006

Adaptive Resource Replication In A Ubiquitous Peertopeer Based Multimedia Distribution Environment, L. Rong, I. Burnett

Faculty of Informatics - Papers (Archive)

A dynamic P2P architecture was proposed in our previous work to support resource adaptation/personalization according to the surrounding usage environment and user preferences. In this paper, we propose an adaptive resource replication strategy based on the proposed P2P architecture. It uses resource request rate as the metric to trigger the resource replication process, and proportionally replicate multimedia resources into various configuration states according to the properties of peers (i.e., terminal capabilities and user preferences) and the size of peer clusters. Also, the strategy uses peer related information stored on super peers to determine which peers should be selected to perform …

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Where Are The Benefits In Crm Technology Investment?, T. R. Coltman Jan 2006

Where Are The Benefits In Crm Technology Investment?, T. R. Coltman

Faculty of Informatics - Papers (Archive)

A common belief today is that sustainable competitive advantages are in some way positively correlated with customer focused behavior and CRM technology. However, the enthusiasm generated around CRM and a select concentration of companies that might be classified as "relationship leaders" is in stark contrast to the nay saying of many business commentators. Building on the resource-based view of the firm this study identifies the human and technological capabilities required to successfully execute a CRM program. Further, the study shows that to be successful, CRM programs must be feasible and this requires a wider understanding of the structural and behavioral …

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Analysis Of A Model For The Treatment Of Wastewater By The Activated Sludge Process, Simon D. Watt, Harvinder S. Sidhu, Mark I. Nelson Jan 2006

Analysis Of A Model For The Treatment Of Wastewater By The Activated Sludge Process, Simon D. Watt, Harvinder S. Sidhu, Mark I. Nelson

Faculty of Informatics - Papers (Archive)

We investigate a model for the treatment of wastewater in the activated sludge process. This process is based on the aeration of waste water with flocculating biological growth, followed by the separation of treated waste water from biological growth. Part of this growth is then wasted, and the remainder is returned to the system. The wastewater reactor is assumed to be well mixed, so the mathematical formulation for this process can be represented by a continuously stirred tank reactor with recycle. This system is analysed by combining steady-state analysis with path-following techniques. In practice, wastewater is treated by a sequence …

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Orbiting Buckyballs Inside Nanotori, Tamsyn A. Hilder, James M. Hill Jan 2006

Orbiting Buckyballs Inside Nanotori, Tamsyn A. Hilder, James M. Hill

Faculty of Informatics - Papers (Archive)

The discovery of carbon nanostructures, such as carbon nanotubes and the so-called buckyballs (or C60 fullerenes), have generated considerable interest for potential nanomechanical device applications. One such device is the high frequency nanoscale gigahertz oscillator. A number of studies investigating these oscillators find that sliding an inner-shell inside an outer-shell of a multi-walled carbon nanotube can generate oscillatory frequencies in the gigahertz range. It is found that the oscillation is sensitive to diameter and helicity of the tube and that the inner tube length can be used to tune the frequency, where the buckyball provides the highest frequency. More recently, …

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Activated Sludge Wastewater Treatment Process: Performance Comparison Between A Two-Reactor Cascade And A Single Tank, Harvinder S. Sidhu, Simon D. Watt, Mark I. Nelson Jan 2006

Activated Sludge Wastewater Treatment Process: Performance Comparison Between A Two-Reactor Cascade And A Single Tank, Harvinder S. Sidhu, Simon D. Watt, Mark I. Nelson

Faculty of Informatics - Papers (Archive)

We Investigate a model for the treatment of wastewater in the activated sludge process. The process is based on the aeration of wastewater with flocculating biological growth, followed by the separation of treated wastewater from biological growth. Part of this growth is wasted, and the remainder returned to the system. The biochemical model consists of two types of bacteria, sludge bacteria and sewage bacteria, and two types of ciliated protozoa, free-swimming ciliates and ciliates attached to sludge floes. A combination of steady-state analysis, path following techniques and numerical integration of the governing equations are used to study the dynamics of …

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The Emerging Ethics Of Humancentric Gps Tracking And Monitoring, Katina Michael, Andrew Mcnamee, M G. Michael Jan 2006

The Emerging Ethics Of Humancentric Gps Tracking And Monitoring, Katina Michael, Andrew Mcnamee, M G. Michael

Faculty of Informatics - Papers (Archive)

The Global Positioning System (GPS) is increasingly being adopted by private and public enterprise to track and monitor humans for location-based services (LBS). Some of these applications include personal locators for children, the elderly or those suffering from Alzheimer's or memory loss, and the monitoring of parolees for law enforcement, security or personal protection purposes. The continual miniaturization of the GPS chipset means that receivers can take the form of wristwatches, mini mobiles and bracelets, with the ability to pinpoint the longitude and latitude of a subject 24/7/365. This paper employs usability context analyses to draw out the emerging ethical …

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Authenticated Aodv Routing Protocol Using One-Time Signature And Transitive Signature Schemes, Shidi Xu, Yi Mu, Willy Susilo Jan 2006

Authenticated Aodv Routing Protocol Using One-Time Signature And Transitive Signature Schemes, Shidi Xu, Yi Mu, Willy Susilo

Faculty of Informatics - Papers (Archive)

Mobile ad hoc network (MANET) has been generally regarded as an ideal network model for group communications because of its specialty of instant establishment. However, the security of MANET is still a challenge issue. Although there are some existing security schemes such as ARAN (Authenticated Routing for Ad hoc Networks) protocol that makes use of cryptographic certificate to provide end-to-end authentication during routing phases, the overhead of security computation is still a serious hurdle for real application. In this paper, we propose a comparatively efficient scheme to perform ARAN protocol, based on AODV, by using one-time signature in place of …

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Exploiting Time Diversity To Improve Block Spread Ofdm, Ibrahim S. Raad, Xiaojing Huang Jan 2006

Exploiting Time Diversity To Improve Block Spread Ofdm, Ibrahim S. Raad, Xiaojing Huang

Faculty of Informatics - Papers (Archive)

This paper presents a new method to improve on block spread OFDM by exploiting time diversity to ensure that the blocks are independent and uncorrelated. Simulation results have shown significant improvement over conventional OFDM and Block Spread OFDM.

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Study Of Spread Codes With Block Spread Ofdm, Ibrahim S. Raad, Xiaojing Huang, Darryn Lowe Jan 2006

Study Of Spread Codes With Block Spread Ofdm, Ibrahim S. Raad, Xiaojing Huang, Darryn Lowe

Faculty of Informatics - Papers (Archive)

This paper presents the study undertaken with block spread OFDM and compares three spreading matrices. The matrices include the Hadamard, Rotated Hadamard and Mutually Orthogonal Complementary Sets of Sequences (MOCSS). The study is carried out for block lengths of M = 2, M = 4 and M = 8 and it shows that all the spreading matrices show improvement and a better performance over the conventional OFDM over frequency selective channel as expected. As the size of M increased the spreading matrices which have better orthogonal qualities show greater improvement.

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Face Classification With Ultrasonic Sensing, Phillip J. Mckerrow, Kok Kai Yoong Jan 2006

Face Classification With Ultrasonic Sensing, Phillip J. Mckerrow, Kok Kai Yoong

Faculty of Informatics - Papers (Archive)

The echo of a chirp of ultrasonic energy from an object contains information about the geometry of that object: relative depth of surfaces and approximate area of those surfaces. A human face has complex geometry that produces a distinctive echo. In this paper, we report initial research into whether there is sufficient information in the echo to recognize a face. Potential features for classification are identified using a facial model. The classification results are poor, but encourage future research to find better quality features.

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Landmark Navigation With Fuzzy Logic, Sherine M. Antoun, Phillip J. Mckerrow Jan 2006

Landmark Navigation With Fuzzy Logic, Sherine M. Antoun, Phillip J. Mckerrow

Faculty of Informatics - Papers (Archive)

Our previous research emulated aeroplane navigation for dead reckoning flight in reasonable weather conditions. In this research, we propose to tackle navigation in a more realistic environment for a mobile robot by modelling it on the case of a tourist in an unfamiliar village. When lost tourists use a variety of strategies to reacquire the path. Here we will emulate these to navigate a mobile robot. We will attempt to develop an intelligent controller, which copes with imprecise inputs, to achieve its commanded tasks safely. The controller will make use of fuzzy logic to make decisions based on data stored …

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Electronic Commerce Adoption Barriers In Indonesian Small Medium-Sized Enterprises (Smes): An Exploratory Study, Mira Kartiwi, Robert Macgregor, Deborah Bunker Jan 2006

Electronic Commerce Adoption Barriers In Indonesian Small Medium-Sized Enterprises (Smes): An Exploratory Study, Mira Kartiwi, Robert Macgregor, Deborah Bunker

Faculty of Informatics - Papers (Archive)

This research seeks to explore and detect underlying relationships between identifiable barriers of electronic commerce (ecommerce) adoption in Indonesian small medium-sized enterprises (SMEs). A quantitative pilot study was conducted through a mail survey to collect the relevant data from several cities in three provinces in Indonesia, namely West Java, Bali and DKI Jakarta. The inter-correlations among the barriers influential to the e-commerce adoption decision demanded the application of principal component analysis to determine the factors perceived to dictate e-commerce adoption decision outcomes. The results of the analysis indicate that correlations between the barriers do exist and that the barriers can …

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Small Business Adoption Of E-Commerce: A Comparison Of B2b And B2c Businesses, Robert Macgregor, Deborah Bunker, Lejla Vrazalic Jan 2006

Small Business Adoption Of E-Commerce: A Comparison Of B2b And B2c Businesses, Robert Macgregor, Deborah Bunker, Lejla Vrazalic

Faculty of Informatics - Papers (Archive)

This paper examines why both B2B and B2C small businesses adopt of E-commerce. It provides an examination of the association between B2B/B2C adoption and other organizational and managerial factors by questioning small business managers about business sector, market focus, gender of the CEO and educational level of the CEO. It also examines the groupings and priorities of criteria used in the decision-making process to adopt E-commerce, to determine whether differences exist between those small businesses that operate primarily in a B2B mode and those that operate primarily in a B2C mode.

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Constant-Size Id-Based Linkable And Revocable-Iff-Linked Ring Signature, Man Ho Allen Au, Joseph K. Liu, Willy Susilo, Tsz Hon Yuen Jan 2006

Constant-Size Id-Based Linkable And Revocable-Iff-Linked Ring Signature, Man Ho Allen Au, Joseph K. Liu, Willy Susilo, Tsz Hon Yuen

Faculty of Informatics - Papers (Archive)

In this paper, we propose a new notion called Revocable-iff-Linked Ring Signature (R-iff-L Ring Signature). In R-iff-L ring signatures, a signer can sign on behalf of the whole group, just like ordinary ring signatures. However, if he signs twice or more, he can be linked and his identity can be revoked by everyone. We formally define a new security model for the new notion in identity-based (ID-based) setting and propose a constant-size ID-based construction, that is, the size of the signature is independent of the size of the group. In addition, we enhance the security model of ID-based linkable ring …

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Constant-Size Dynamic K-Taa, Man Ho Allen Au, Willy Susilo, Yi Mu Jan 2006

Constant-Size Dynamic K-Taa, Man Ho Allen Au, Willy Susilo, Yi Mu

Faculty of Informatics - Papers (Archive)

k-times anonymous authentication (k-TAA) schemes allow members of a group to be authenticated anonymously by application providers for a bounded number of times. Dynamic k-TAA allows application providers to independently grant or revoke users from their own access group so as to provide better control over their clients. In terms of time and space complexity, existing dynamic k-TAA schemes are of complexities O(k), where k is the allowed number of authentication. In this paper, we construct a dynamic k-TAA scheme with space and time complexities of O(log(k)). We also outline how to construct dynamic k-TAA scheme with a constant proving …

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A Parallel Key Generation Algorithm For Efficient Diffie-Hellman Key Agreement, Yun Chen, Xin Chen, Yi Mu Jan 2006

A Parallel Key Generation Algorithm For Efficient Diffie-Hellman Key Agreement, Yun Chen, Xin Chen, Yi Mu

Faculty of Informatics - Papers (Archive)

The kernel function of the Diffie-Hellman (DH) protocol is a modular exponentiation over finite field with high computational complexity. In this paper, we propose a novel key generation algorithm for DH agreement that derives computational efficiency from constructing a parallel architecture. Compared to the serial structure for traditional binary representation (BR) method, our algorithm is significantly more efficiency on key generation and suitable for hardware implementation in an ephemeral-static mode for DH agreement which is thought to be more secure (Rosorla, 1999)

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Server-Aided Public Key Generation Protocols On Low-Power Devices For Ad-Hoc Networks, Yun Chen, Weijian Chen, Yi Mu, Xin Chen, Min Liu Jan 2006

Server-Aided Public Key Generation Protocols On Low-Power Devices For Ad-Hoc Networks, Yun Chen, Weijian Chen, Yi Mu, Xin Chen, Min Liu

Faculty of Informatics - Papers (Archive)

Against the problems emerged in protocols presented by N. Modadugu, D.Boneh and M. Kim (2000), new server-aided public key generation protocols on low-power devices are proposed in this paper. The protocols are secure against some passive attacks, such as "collusion attack" and "the third party attack". In addition, efficiency of primality test on low-power devices is improved in this paper. Prospective applications of the protocols would be found in mobile e-commence, mobile ad-hoc, and military communications.

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An Efficient Approach To Generic Multimedia Adaptation, Joseph Thomas-Kerr, I. Burnett, Christian Ritz Jan 2006

An Efficient Approach To Generic Multimedia Adaptation, Joseph Thomas-Kerr, I. Burnett, Christian Ritz

Faculty of Informatics - Papers (Archive)

This paper addresses efficiency issues identified in the Bitstream Syntax Description Language used by the MPEG-21 generic multimedia adaptation framework. In particular, when used to adapt modern content formats such as H.264/AVC, the time required for processing increases exponentially relative to the duration of the bitstream. In response, the paper proposes several additional features for the Bitstream Syntax Description Language which reduce the complexity of adaptation using BSDL to a linear function of bitstream duration. These features are implemented and validated using bitstreams of real-world length.

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