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Articles 31 - 60 of 211
Full-Text Articles in Physical Sciences and Mathematics
Optimisation Of Triangulation Based Optical Profilometers Utilising Digital Video Projection Technology, Matthew J. Baker, Jiangtao Xi, Joe F. Chicharo, Enbang Li
Optimisation Of Triangulation Based Optical Profilometers Utilising Digital Video Projection Technology, Matthew J. Baker, Jiangtao Xi, Joe F. Chicharo, Enbang Li
Faculty of Informatics - Papers (Archive)
Fast, high precision and automated optical noncontact surface profile and shape measurement has been an extensively studied research area due to its many potential applications including 3D sensing, industrial monitoring, mechanical engineering, medicine, robotics, machine vision,animation, virtual reality, dressmaking, prosthetics, ergonomics. Among others, structured light approaches including fringe profilometry have proven to be one of the most promising techniques. In such profilometry techniques a structured light pattern, generally composed of parallel lines is projected onto a diffuse surface to be measured and viewed from an offset angle. The observed pattern is distorted by the object in such a way that …
Multi-Point Fiber Bragg Grating Based Vibration Measurement System With High Sensitivity And Fast Frequency Response, Enbang Li, Jiangtao Xi, Joe F. Chicharo
Multi-Point Fiber Bragg Grating Based Vibration Measurement System With High Sensitivity And Fast Frequency Response, Enbang Li, Jiangtao Xi, Joe F. Chicharo
Faculty of Informatics - Papers (Archive)
We have proposed and demonstrated a new fiber Bragg grating (FBG) based vibration measurement system which can demodulate vibration signals from wavelength-multiplexed FBG sensors with high sensitivity and fast frequency response.
A Novel Ieee 802.15.3 Cta Sharing Protocol For Supporting Vbr Streams, Kwan-Wu Chin, Darryn Lowe
A Novel Ieee 802.15.3 Cta Sharing Protocol For Supporting Vbr Streams, Kwan-Wu Chin, Darryn Lowe
Faculty of Informatics - Papers (Archive)
The IEEE 802.15.3 MAC enables high-rate communications between devices in a wireless personal area network and has good support for applications requiring quality of service (QoS). To meet applications' QoS requirements, such as delay and jitter, the channel time allocation (CTA) scheduler plays an important role in sizing and positioning CTAs within each super-frame. In this paper, we first present a novel CTA sharing protocol, called VBR-MCTA that enables the sharing of CTAs belonging to streams with the same group identity. This allows our protocol to exploit the statistical characteristics of variable bit rate (VBR) streams by giving unused time …
Ardez: A Low Power Asymmetric Rendezvous Mac For Sensor Networks, K. Chin, Mohammed Raad
Ardez: A Low Power Asymmetric Rendezvous Mac For Sensor Networks, K. Chin, Mohammed Raad
Faculty of Informatics - Papers (Archive)
We present a rendezvous based medium access control (MAC), culled ArDeZ, for use in sensor networks. ArDeZ is a TDMA based medium access scheme that does not rely on strict time slot positioning and assignments, making ArDeZ easily deployable in large sensor networks without having to adhere to strict time slot boundaries. ArDeZ establishes two independent peer-to-peer time channels between nodes, and these channels do not necessarily have the same duty cycle. Each channel has a set of rendezvous periods associated with it that are generated from a seed exchanged during the setup process. Further, the duration and frequency of …
Bounds On Authentication Systems In Query Mode, R. Safavi-Naini, P. Wild
Bounds On Authentication Systems In Query Mode, R. Safavi-Naini, P. Wild
Faculty of Informatics - Papers (Archive)
Unconditionally secure authentication codes provide information theoretic security against an adversary who observes authenticated messages and then wants to construct a fraudulent message that is acceptable by the receiver. The attack model for these codes has recently been strengthened and adaptive adversaries with oracle access have been introduced. In this paper we give an analysis of this new model and derive information theoretic bounds on the success probability and key size of the codes. Our analysis treats two games that an adversary can play: an offline attack in which the adversary is allowed to query a verification oracle and then …
Deploying The Digital Aid Framework: A Non-Traditionalist View Of The Intrinsic Nature Of E-Business Solutions For Humanitarian Relief, J. Sargent
Faculty of Informatics - Papers (Archive)
Commercial Fortune 500 companies come readily to mind in any discussion or categorization of global e- Businesses. However, organizations within the international humanitarian relief sector such as UNHCR, the UN’s refugee agency, are consistently over-looked or underestimated as global ‘e-Biz’ players. This paper acts as a primer for the principles of e-Business for humanitarian relief by presenting deployment examples of traditional e-Business processes in non-traditional contexts; refugee and Internally Displaced Person (IDP) crises. Preliminary research indicates such illustrated indicative examples detailed in the Digital Aid Framework have potential for easy adoption and integration into future humanitarian (refugee & IDP) relief …
Humancentric Applications Of Precise Location Based Services, L. Perusco, Katina Michael
Humancentric Applications Of Precise Location Based Services, L. Perusco, Katina Michael
Faculty of Informatics - Papers (Archive)
This paper focuses on the growing need to consider the implications of humancentric applications of precise location based services (LBS). As newer positioning technologies are introduced into the market with a greater level of location accuracy, and existing technologies are utilized in an integrated fashion to overcome limitations, issues pertaining to the use and potential misuse of location information rise to the fore. The scenario planning methodology provides a robust approach within which to consider future possibilities based on current market developments. To this end, document and content analysis play an important role in the collection of facts used to …
Is It The End Of Barcodes In Supply Chain Management? , Luke Mccathie, Katina Michael
Is It The End Of Barcodes In Supply Chain Management? , Luke Mccathie, Katina Michael
Faculty of Informatics - Papers (Archive)
Barcode is a mature automatic identification (auto-ID) technology that has been used in supply chain management (SCM) for several decades. Such has been the domination of the auto-ID technique that it has pervaded all facets of SCM, from item-level identification to transportation applications. It has enjoyed free reign especially in the retail sector. However, recently radio-frequency identification (RFID) has been considered a rival technology, more superior in terms of its power to store and update information instantaneously, and non-line of sight (nLoS) ability to be read. Yet RFID is more costly and for the present barcode is still the most …
On The Performance Of Turbo Codes With Convolutional Interleavers, Sina Vafi, Tadeusz A. Wysocki
On The Performance Of Turbo Codes With Convolutional Interleavers, Sina Vafi, Tadeusz A. Wysocki
Faculty of Informatics - Papers (Archive)
In this paper, some issues governing the block-wise performance of convolutional interleavers used in turbo codes are presented. Two different constructions of convolutional interleaver differing by the position of stuff bits in the interleaved data block are considered here. The performance assessment is based on the contribution of each weight to the overall code performance. For the given turbo code and each utilized interleaver, weight contribution is computed to finalize the code behavior in different signal to noise ratios. Simulations have been performed to verify the conducted analysis.
Mpeg-21 In Backpack Journalism Scenario, G. Drury, I. Burnett
Mpeg-21 In Backpack Journalism Scenario, G. Drury, I. Burnett
Faculty of Informatics - Papers (Archive)
The vision of MPEG-21-the multimedia framework-is to enable transparent and augmented use of multimedia resources across a wide range of networks and devices used by different communities. As the initial standardization effort for MPEG-21 reaches its conclusion, this article explores one case scenario and examines whether MPEG-21 can achieve its vision.
The Structure And Components Of E-Mall Business Models, Renae Cooper, Katina Michael
The Structure And Components Of E-Mall Business Models, Renae Cooper, Katina Michael
Faculty of Informatics - Papers (Archive)
This paper is concerned with e-mall business models. The investigation defines what constitutes an e-mall, the different types of implementations, and surveys a number of established e-malls. The study looks at e-malls through the eyes of a buyer and seller and describes the different types of components available to each on e-malls including categorization, payment facilities and considerations, site linking and redirection, buyer traffic, loyalty and advertising schemes and legalities. It becomes apparent throughout the paper that e-malls use a diverse number of strategies in their implementations, and that sellers using e-malls maintain their autonomy as individual retailers. Therefore while …
The Rise And Fall Of Digital Music Distribution Services: A Cross-Case Comparison Of Mp3.Com, Napster And Kazaa, K. Alves, Katina Michael
The Rise And Fall Of Digital Music Distribution Services: A Cross-Case Comparison Of Mp3.Com, Napster And Kazaa, K. Alves, Katina Michael
Faculty of Informatics - Papers (Archive)
The aim of this research is to assess the role of digital music distribution services in the downturn and restructuring of the music industry. The research was bound by the systems of innovation conceptual framework and explores the dynamics between the technical, social, legal and economic dimensions with the purpose of understanding how the traditional supply chain has changed. The cases of MP3.com, Napster and Kazaa are studied for their historical significance and the sheer breadth of issues they bring to the fore. Data was collected using documentation review and interviews. The findings of the research show that the creation …
Performance Investigation On Three-Classes Of Manet Routing Protocols, Mehran Abolhasan, Tadeusz A. Wysocki, Justin Lipman
Performance Investigation On Three-Classes Of Manet Routing Protocols, Mehran Abolhasan, Tadeusz A. Wysocki, Justin Lipman
Faculty of Informatics - Papers (Archive)
Routing in Ad-hoc Networks has received significant attention with a number of different routing protocols proposed in recent years. These routing protocols may be classified into three main categories: proactive, reactive and hybrid. Prior work aimed at comparing the performance of routing protocols has mainly fo cused on comparing reactive and proactive protocols [6] [4] [1]. In this paper, we present a simulation study of different routing protocols from all three categories. We also explore the benefits and performance of each routing category. Further, we present a discussion of future research directions for routing in Ad-hoc Networks.
The Behavior Of Manet Routing Protocols In Realistic Environments, K. Chin
The Behavior Of Manet Routing Protocols In Realistic Environments, K. Chin
Faculty of Informatics - Papers (Archive)
This paper presents an analysis of MANET routing protocols’ behavior in realistic channel fading scenarios. The motivation of this study was due to our previous testbed experimentations where we found that AODV and DSDV’s performance did not match simulation results, primarily due to the use of a simple radio propagation model that did not take into account transient links caused by small-scale fading. Henceforth, we extended the ns-2 simulator with a realistic radio propagation model, that incorporated Rayleigh fading, to gain insights into the impact of transient links on AODV, DSR, and DSDV’s behaviour. Our simulation studies explain each protocol’s …
A Cryptographic Solution For General Access Control, Y. Kong, Jennifer Seberry, J. R. Getta, Ping Yu
A Cryptographic Solution For General Access Control, Y. Kong, Jennifer Seberry, J. R. Getta, Ping Yu
Faculty of Informatics - Papers (Archive)
As one of the most popular information safeguarding mechanisms, access control is widely deployed in information systems. However, access control approach suffers from a tough problem, i.e. system administrators must be unconditionally trusted. Cryptographic substitutes have been developed to solve the above problem. In particular, hierarchical encryption, as an alternate solution of access control in a hierarchy, has been intensively studied. In this paper, we propose a cryptographic solution for general access control based on Chinese Remainder Theorem. Our solution has two categories: data based solution and key based solution. In contrast to the most recent hierarchical encryption system: Ray, …
Executable Specifications For Agent Oriented Conceptual Modelling, Y. Guan, Aditya K. Ghose
Executable Specifications For Agent Oriented Conceptual Modelling, Y. Guan, Aditya K. Ghose
Faculty of Informatics - Papers (Archive)
Agent-oriented conceptual modelling (AoCM) notations such as i* have received considerable recent attention as a useful approach to early-phase requirements engineering. AoCM notations are useful in modeling organizational context and in offering high-level anthropomorphic abstractions as modeling constructs. AoCM notations such as i* help answer questions such as what goals exist, how key actors depend on each other and what alternatives must be considered. In this paper, we suggest an approach to executing i* models by translating these into set of interacting agents implemented in the 3APL language. In addition, we suggest a hybrid modeling, or co-evolution, approach in which …
Simultaneous Map Estimation Of Inhomogeneity And Segmentation Of Brain Tissues From Mr Images, Wanqing Li, C. Desilver, Y. Attikiouzel
Simultaneous Map Estimation Of Inhomogeneity And Segmentation Of Brain Tissues From Mr Images, Wanqing Li, C. Desilver, Y. Attikiouzel
Faculty of Informatics - Papers (Archive)
Intrascan and interscan intensity inhomogeneities have been identified as a common source of making many advanced segmentation techniques fail to produce satisfactory results in separating brains tissues from multi-spectral magnetic resonance (MR) images. A common solution is to correct the inhomogeneity before applying the segmentation techniques. This paper presents a method that is able to achieve simultaneous semi-supervised MAP (maximum a-posterior probability) estimation of the inhomogeneity field and segmentation of brain tissues, where the inhomogeneity is parameterized. Our method can incorporate any available incomplete training data and their contribution can be controlled in a flexible manner and therefore the segmentation …
Generalized Williamson And Wallis-Whiteman Constructions For Improved Square Order-8 Co Stbcs, Le Chung Tran, Tadeusz A. Wysocki, Jennifer Seberry, A. Mertins, Sarah A. Spence
Generalized Williamson And Wallis-Whiteman Constructions For Improved Square Order-8 Co Stbcs, Le Chung Tran, Tadeusz A. Wysocki, Jennifer Seberry, A. Mertins, Sarah A. Spence
Faculty of Informatics - Papers (Archive)
Constructions of square, maximum rate Complex Orthogonal Space-Time Block Codes (CO STBCs) are well known, however codes constructed via the known methods include numerous zeros, which impede their practical implementation. By modifying the Williamson and Wallis-Whiteman arrays to apply to complex matrices, we propose two methods of construction of square, order-4n CO STBCs from square, order-n codes which satisfy certain properties. Applying the proposed methods, we construct square, maximum rate, order-8 CO STBCs with no zeros, such that the transmitted symbols equally disperse through transmit antennas. Those codes, referred to as the improved square CO STBCs, have the advantages that …
The Power And Influence In Some Youden Squares And Secret Sharing, L. Fitina, Ken Russell, Jennifer Seberry
The Power And Influence In Some Youden Squares And Secret Sharing, L. Fitina, Ken Russell, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We investigate subsets of critical sets of some Youden squares in the context of secret sharing schemes. A subset C of a Youden square is called a critical set, if C can be uniquely completed to a Youden square but any subset of C cannot does not have a unique completion to a Youden square. That part of a Youden square Y which is inaccessible to subsets of a critical set C of Y, called the strongbox of C, may be thought to contain secret information. We study the size of the secret. Seberry and Street have shown how strongboxes …
Optical Signal Processing For Fiber Bragg Grating Based Wear Sensors, Enbang Li, Jiangtao Xi, Joe F. Chicharo
Optical Signal Processing For Fiber Bragg Grating Based Wear Sensors, Enbang Li, Jiangtao Xi, Joe F. Chicharo
Faculty of Informatics - Papers (Archive)
In this study, we propose a simplified signal processing scheme for fiber Bragg grating (FBG) based wear sensing. Instead of using a chirped FBG and detecting the bandwidth, we use uniform gratings as sensors and measure the optical power reflected by the sensing grating to determine the length of the sensor grating, hence detect the wear. We demonstrate by the experiments that the proposed method is feasible and practical. The advantage of the proposed method lies in the fact that structure of the wear sensing system is simplified and therefore the cost can be significantly reduced. The principle of the …
A Half-Frequency Domain Approach For Convolutive Blind Source Separation Based On Kullback-Leibler Divergence, T. Mei, Fuliang Yin, Jiangtao Xi, Alfred Mertins, Joe F. Chicharo
A Half-Frequency Domain Approach For Convolutive Blind Source Separation Based On Kullback-Leibler Divergence, T. Mei, Fuliang Yin, Jiangtao Xi, Alfred Mertins, Joe F. Chicharo
Faculty of Informatics - Papers (Archive)
This paper studies the problem of blind separation of convolutive mixtures by means of Kullback-Leibler divergence in frequency domain. Unlike exiting approaches, an integrated objective function is defined in frequency-domain with time-domain parameters as the variables. The permutation problem is avoided through the frequency domain integration and time domain optimization. Simulation results show that the algorithm is valid and of high performance for the separation of real world recorded convolutive mixtures.
An Investigation Of Temporal Modeling In Blind Signal Separation, Daniel Smith, Jason Lukasiak, Ian Burnett
An Investigation Of Temporal Modeling In Blind Signal Separation, Daniel Smith, Jason Lukasiak, Ian Burnett
Faculty of Informatics - Papers (Archive)
This paper investigates the performance of blind signal separation (BSS) algorithms that exploit the temporal predictability of speech. Specifically, the investigation considers how the separation performance of two BSS algorithms will be affected when the length of the AR process (used in the algorithms to model speech) is varied. The investigation concludes that the length of the AR process (prediction order) has a significant impact on separation performance. In particular, the separation performance of both algorithms is degraded, if the AR model’s prediction order, over fits, or under fits, the temporal structure of the speech. It is revealed that a …
Shift Estimation Method Based Fringe Pattern Profilometry And Performance Comparison, Y. Hu, Jiangtao Xi, Enbang Li, Joe F. Chicharo, Zongkai Yang
Shift Estimation Method Based Fringe Pattern Profilometry And Performance Comparison, Y. Hu, Jiangtao Xi, Enbang Li, Joe F. Chicharo, Zongkai Yang
Faculty of Informatics - Papers (Archive)
In this paper, we present and study two approaches to fringe pattern profilometry (FPP) technique. Based on generalized analysis model for fringe pattern profilometry (FPP), Inverse Function based Shift Estimation (IFSE) and Gradient-based Shift Estimation (GSE) are proposed to calculate the shift between the projected and deformed fringe patterns. Further, computer simulations are utilized to compare the performance between these two methods. Meanwhile, we also compare these two algorithms with Phase Shift profilometry (PSP). It can be seen that both of these two shift estimation algorithms can significantly improve the measurement accuracy when the fringe patterns are nonlinearly distorted.
An Improved Dynamic Model For Optical Feedback Self-Mixing Interferometry-Based Measurement And Instrumentation, Jiangtao Xi, Yuanguang Yu, Enbang Li, Joe F. Chicharo
An Improved Dynamic Model For Optical Feedback Self-Mixing Interferometry-Based Measurement And Instrumentation, Jiangtao Xi, Yuanguang Yu, Enbang Li, Joe F. Chicharo
Faculty of Informatics - Papers (Archive)
This paper presents a new model that describes the behaviour of optical feedback self-mixing interferometry (OFSMI). Compared to the existing model, the proposed one does not suffer from the multiple value ambiguity problems. The proposed model is a dynamic one that gives a unique relationship between the external target moving law and the self-mixing signal (SMS) waveform (SMS) when other parameters are given. A computer simulation tool for OFSMI has been implemented to generate SMS waveforms and its effectiveness has been verified by experimental data.
Wireless Ad-Hoc Control Networks, Shengrong Bu, Fazel Naghdy
Wireless Ad-Hoc Control Networks, Shengrong Bu, Fazel Naghdy
Faculty of Informatics - Papers (Archive)
A new concept called wireless ad-hoc control networks (WACNets), designed for distributed and remote monitoring and control is suggested in this work. Such systems represent the next stage in the evolution of distributed control and monitoring. WACNet explores a framework for organic, evolutionary and scalable method of integrating a large number of nodes with sensing and/or actuation, local intelligence and control, data processing and communication capabilities. The concept is introduced and the design of the network is presented. As an essential element in the operation of WACNet, service discovery developed for WACNet will be described and progress made so far …
Estimating The Parameters Of Semiconductor Lasers Based On Weak Optical Feedback Self-Mixing Interferometry, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo, T. Bosch
Estimating The Parameters Of Semiconductor Lasers Based On Weak Optical Feedback Self-Mixing Interferometry, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo, T. Bosch
Faculty of Informatics - Papers (Archive)
The paper presents a practical approach for measuring the linewidth enhancement factor /spl alpha/ of semiconductor lasers and the optical feedback level factor C in a semiconductor laser with an external cavity. The proposed approach is based on the analysis of the signals observed in an optical feedback self-mixing interferometric system. The parameters /spl alpha/ and C are estimated using a gradient-based optimization algorithm that achieves best data-to-theoretical model match. The effectiveness and accuracy of the method has been confirmed and tested by computer simulations and experiments, which show that the proposed approach is able to estimate /spl alpha/ and …
A Coloured Petri Net Based Strategy For Multi-Agent Scheduling, Q. Bai, Minjie Zhang, H. Zhang
A Coloured Petri Net Based Strategy For Multi-Agent Scheduling, Q. Bai, Minjie Zhang, H. Zhang
Faculty of Informatics - Papers (Archive)
In the last decade, the focus of agent research has shifted from single agent systems to multi-agent systems (MASs). Dynamic agent coordination is one of the challenge problems of multi-agent research. One coordination problem is how to achieve agent scheduling under open dynamic environments. Petri Nets (PNs) and Coloured Petri Nets (CPNs) are system study tools that provide an appropriate mathematical formalism for the description, construction and analysis of distributed and concurrent systems. In this paper, we present a CPN based strategy to schedule and allocate new tasks to suitable agent(s) or agent combinations. In this strategy, through using CPNs …
Universal Designated Multi Verifier Signature Schemes, Ching Yu Ng, Willy Susilo, Y. Mu
Universal Designated Multi Verifier Signature Schemes, Ching Yu Ng, Willy Susilo, Y. Mu
Faculty of Informatics - Papers (Archive)
The notion of Universal Designated-Verifier Signatures was put forth by Steinfeld et. al. in Asiacrypt 2003. This notion allows a signature holder to designate the signature to a desired designated-verifier. In this paper, we extend this notion to allow a signature holder to designate the signature to multi verifiers, and hence, we call our scheme as Universal Designated Multi Verifier Signatures. We provide security proofs for our schemes based on the random oracle model.
Delegatable Access Control For Fine-Grained Xml, Jing Wu, Jennifer Seberry, Y. Mu, Chun Ruan
Delegatable Access Control For Fine-Grained Xml, Jing Wu, Jennifer Seberry, Y. Mu, Chun Ruan
Faculty of Informatics - Papers (Archive)
The access control mechanisms are critical to ensure security in XML (eXtensible Markup Language). Several such mechanisms have been used or proposed; however, the notion of delegation in XML has not been studied in the literature. In this paper, we propose an access control model encapsuling delegation authorization rules for XML documents that allow flexible data granularity and limited inference protection. Our access control policy specification is basically DTD-based. It can also be considered to be document-based.
Humancentric Applications Of Rfid Implants: The Usability Contexts Of Control, Convenience And Care, Amelia Masters, Katina Michael
Humancentric Applications Of Rfid Implants: The Usability Contexts Of Control, Convenience And Care, Amelia Masters, Katina Michael
Faculty of Informatics - Papers (Archive)
Recent developments in the area of RFID have seen the technology expand from its role in industrial and animal tagging applications, to being implantable in humans. With a gap in literature identified between current technological development and future humancentric possibility, little has been previously known about the nature of contemporary humancentric applications. This paper utilizes usability context analyses, to provide a cohesive study on the current development state of humancentric applications, detached from the emotion and prediction which plagues this particular technology.