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Faculty of Informatics - Papers (Archive)

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Articles 1261 - 1290 of 2013

Full-Text Articles in Physical Sciences and Mathematics

Analysis Of The Michaelis-Menten Mechanism In An Immobilised Enzyme Reactor, Mark Nelson, Xiao Dong Chen, M. J. Sexton Jan 2005

Analysis Of The Michaelis-Menten Mechanism In An Immobilised Enzyme Reactor, Mark Nelson, Xiao Dong Chen, M. J. Sexton

Faculty of Informatics - Papers (Archive)

We investigate the behaviour of a reaction described by Michaelis-Menten kinetics in an immobilised enzyme reactor (IER). The IER is treated as a well-stirred flow reactor, with the restriction that bounded and unbounded enzyme species are constrained to remain within the reaction vessel. Our aim is to identify the best operating conditions for the reactor. The cases in which an immobilised enzyme reactor is used to either reduce pollutant emissions or to synthesise a product are considered. For the former we deduce that the reactor should be operated using low flow rates whereas for the latter high flow rates are …

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Distance Education Teaching And Tutoring: Two Evolving Australian Models, A. Fuller, Penelope Mcfarlane, Patricia Cretchley, Christine Mcdonald, Cam Le Lam Jan 2005

Distance Education Teaching And Tutoring: Two Evolving Australian Models, A. Fuller, Penelope Mcfarlane, Patricia Cretchley, Christine Mcdonald, Cam Le Lam

Faculty of Informatics - Papers (Archive)

Many Australian universities have entered the distance education market, offering degree programs throughout South East Asia. Although each university offers their programs in a variety of styles, the common factor is the use of computer and web based technologies to not only support the subject’s content, but to facilitate the communication between the students and their academics. Students have accepted this mode of delivery through the presence of their local academics, who have facilitated their use of the technology. Without their local input, both academically and culturally, it can be seen that student use of computer based technology would be …

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Embedded Lossless Audio Coding Using Linear Prediction And Cascade, Kevin Adistambha, Christian Ritz, Jason Lukasiak Jan 2005

Embedded Lossless Audio Coding Using Linear Prediction And Cascade, Kevin Adistambha, Christian Ritz, Jason Lukasiak

Faculty of Informatics - Papers (Archive)

Embedded lossless audio coding is a technique for embedding a perceptual audio coding bitstream within a lossless audio coding bitstream. This paper provides an investigation into a lossless embedded audio coder based on the AAC coder and utilising both backward Linear Predictive Coding (LPC) and cascade coding. Cascade coding is a technique for entropy coding of large dynamic range integer sequences that has the advantage of simple implementation and low complexity. Results show that employing LPC in an embedded architecture achieves approximately an 8% decrease in the coding rate. The overall compression performance of cascade coding closely follows Rice coding, …

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Knowledge-Based Semantic Image Segmentation And Global Precedence Effect, Fardin Akhlaghian Tab, Golshah Naghdy Jan 2005

Knowledge-Based Semantic Image Segmentation And Global Precedence Effect, Fardin Akhlaghian Tab, Golshah Naghdy

Faculty of Informatics - Papers (Archive)

This paper introduces a knowledge-based semantic image segmentation which extracts the "object(s)-of-interest" from the image. Image templates are the high-level knowledge in the system. The major contribution of this work is the use of the "Global Precedence Effect" (forest before trees) of the human visual system (HVS) in image analysis and understanding. The "object-of-interest" is searched for hierarchically through an irregular pyramid by an affine invariant comparison between the different region combinations and the template starting from lowest to the highest resolutions. The global/large size objects are found at lower resolutions with significantly lower computational complexity.

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Certificateless Public Key Encryption Without Pairing, Joonsang Baek, R. Safavi-Naini, Willy Susilo Jan 2005

Certificateless Public Key Encryption Without Pairing, Joonsang Baek, R. Safavi-Naini, Willy Susilo

Faculty of Informatics - Papers (Archive)

“Certificateless Public Key Cryptography” has very appealing features, namely it does not require any public key certification (cf. traditional Public Key Cryptography) nor having key escrow problem (cf. Identity-Based Cryptography). Unfortunately, construction of Certificateless Public Key Encryption (CLPKE) schemes has so far depended on the use of Identity-Based Encryption, which results in the bilinear pairing-based schemes that need costly operations. In this paper, we consider a relaxation of the original model of CLPKE and propose a new CLPKE scheme that does not depend on the bilinear pairings. We prove that in the random oracle model, our scheme meets the strong …

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Universal Designated Verifier Signature Proof (Or How To Efficiently Prove Knowledge Of A Signature), Joonsang Baek, R. Safavi-Naini, Willy Susilo Jan 2005

Universal Designated Verifier Signature Proof (Or How To Efficiently Prove Knowledge Of A Signature), Joonsang Baek, R. Safavi-Naini, Willy Susilo

Faculty of Informatics - Papers (Archive)

Proving knowledge of a signature has many interesting applications. As one of them, the Universal Designated Verifier Signature (UDVS), introduced by Steinfeld et al. in Asiacrypt 2003 aims to protect a signature holder’s privacy by allowing him to convince a verifier that he holds a valid signature from the signer without revealing the signature itself. The essence of the UDVS is a transformation from a publicly verifiable signature to a designated verifier signature, which is performed by the signature holder who does not have access to the signer’s secret key. However, one significant inconvenience of all the previous UDVS schemes …

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Efficient Multi-Receiver Identity-Based Encryption And Its Application To Broadcast Encryption, Joonsang Baek, R. Safavi-Naini, Willy Susilo Jan 2005

Efficient Multi-Receiver Identity-Based Encryption And Its Application To Broadcast Encryption, Joonsang Baek, R. Safavi-Naini, Willy Susilo

Faculty of Informatics - Papers (Archive)

In this paper, we construct an efficient “multi-receiver identity-based encryption scheme”. Our scheme only needs one (or none if precomputed and provided as a public parameter) pairing computation to encrypt a single message for n receivers, in contrast to the simple construction that re-encrypts a message n times using Boneh and Franklin’s identity-based encryption scheme, considered previously in the literature. We extend our scheme to give adaptive chosen ciphertext security. We support both schemes with security proofs under precisely defined formal security model. Finally, we discuss how our scheme can lead to a highly efficient public key broadcast encryption scheme …

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Effects Of Polyethylene Bags, Ethylene Absorbent And 1-Methylcyclopropene On The Storage Of Japanese Pears, M. J. Szczerbanik, K. J. Scott, J. E. Paton, D J. Best Jan 2005

Effects Of Polyethylene Bags, Ethylene Absorbent And 1-Methylcyclopropene On The Storage Of Japanese Pears, M. J. Szczerbanik, K. J. Scott, J. E. Paton, D J. Best

Faculty of Informatics - Papers (Archive)

Storage of the ‘Nijisseiki’ cultivar of Japanese pears was studied over three seasons for periods up to 36 weeks at 0°C. Storage in 50 pm thick low-density polyethylene (LDPE) bags at 0°C considerably delayed yellowing in all experiments, even after fruit was removed to 20°C for 1 week at the end of storage. The addition of an ethylene absorbent made from potassium permanganate on aluminium oxide (Purafil II) further delayed yellowing. Carbon dioxide levels in both treatments varied, but were generally in the range 2-3%. Oxygen levels remained high, generally 16-19%. In bags without Purafil, ethylene levels rose slightly during …

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Satellite Dvb Multicast For Remote Desert Community Messaging, A. Eyers, Mehran Abolhasan Jan 2005

Satellite Dvb Multicast For Remote Desert Community Messaging, A. Eyers, Mehran Abolhasan

Faculty of Informatics - Papers (Archive)

A key issue for remote Australian desert community viability is providing services such as health and education, particularly given the limited telecommunications infrastructure. To help address this issue, we examine how satellite Digital Video Broadcast (DVB) TV can support new telecommunications services for these communities. In particular, we consider options for the DVB based multicast which underpins these services. We show that existing DVB and MHP capabilities can provide the required multicast support.

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Continued Fractions And The Gauss Map, Bruce Bates, Martin Bunder, Keith Tognetti Jan 2005

Continued Fractions And The Gauss Map, Bruce Bates, Martin Bunder, Keith Tognetti

Faculty of Informatics - Papers (Archive)

We discovered properties of the Gauss Map and its iterates using continued fractions. In particular, we find all points and show that the graph of an iterate over [0, 1/2] is symmetric to the graph of the next higher iterate over [1/2,1].

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Conceptual Modelling Of Computations On Data Streams, Anita Dani, Janusz Getta Jan 2005

Conceptual Modelling Of Computations On Data Streams, Anita Dani, Janusz Getta

Faculty of Informatics - Papers (Archive)

This paper proposes a new symbolic language for the conceptual modelling of computations on data streams. We consider a class of algorithms related to the evaluation of mathematical operators on data streams. A vector model is defined to represent the sliding windows. A graph abstraction is used to model the algorithms. The notation is general enough to be used for visualisation and optimisation of a wide class of data stream processing applications.

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Stereophonic Acoustic Echo Cancellation, Fenglu Ge, Prashan Premaratne, Jiangtao Xi Jan 2005

Stereophonic Acoustic Echo Cancellation, Fenglu Ge, Prashan Premaratne, Jiangtao Xi

Faculty of Informatics - Papers (Archive)

This paper presents a new approach for Stereophonic acoustic echo cancellation (SAEC), based on a combination of J-H network and the natural gradient algorithm. In the new approach for SAEC, Computer simulations show that echoes are significantly reduced.

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Dealing With Web Service Qos Factors Using Constraint Hierarchy, Y. Guan, Aditya K. Ghose Jan 2005

Dealing With Web Service Qos Factors Using Constraint Hierarchy, Y. Guan, Aditya K. Ghose

Faculty of Informatics - Papers (Archive)

Functionality and non-functional properties are two critical factors in web service technology, but non-functional properties (quality factors) are often ignored. Usually, these are articulated as statements of objectives, as opposed to prepositional assertions. A key challenge in dealing with objectives is that there is no obvious means to decide when they are satisfied. In effect, these objectives are never fu lly satisfied, but satisficed to varying degrees. Alternative design decisions need to trade-off varying degrees of satisfaction of potentially mutually contradictory non-functional requirements. In some circumstances, non-Junctional properties are crucial; they do affect the design decision. Upon a request, there …

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Loosely-Coupled Consistency Between Agent-Oriented Conceptual Models And Z Specifications, Aneesh Krishna, Aditya K. Ghose, Sergiy A. Viklomir Jan 2005

Loosely-Coupled Consistency Between Agent-Oriented Conceptual Models And Z Specifications, Aneesh Krishna, Aditya K. Ghose, Sergiy A. Viklomir

Faculty of Informatics - Papers (Archive)

Agent-oriented conceptual modelling (AOCM) is a relatively new technique that offers significant benefits in the modelling and development of complex computer systems. It is highly effective in answering questions such that what are the main goals of the system, how key actors depend on each other, and what alternatives exist. A formal method can benefit any stage of the software development lifecycle and improves the quality of the computer systems. The paper defines an approach that allows to complement requirements modelling notations with formal specifications, while preserving the consistency between them.

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The Experimental Evaluation Of Fbg Sensor For Strain Measurement Of Prestressed Steel Strand, Enbang Li, Jiangtao Xi, Joe F. Chicharo, Tiegen Liu, Xin Li, Junfeng Jiang, Lina Li, Yunxin Wang Jan 2005

The Experimental Evaluation Of Fbg Sensor For Strain Measurement Of Prestressed Steel Strand, Enbang Li, Jiangtao Xi, Joe F. Chicharo, Tiegen Liu, Xin Li, Junfeng Jiang, Lina Li, Yunxin Wang

Faculty of Informatics - Papers (Archive)

Multi-wire steel strands have been widely used in various prestressed concrete structures. In this study, experimental evaluation of fiber Bragg grating (FBG) sensors for strain measurements in a seven-wire prestressed steel strand has been carried out. An installation technique of FBG sensors has been developed to fulfill the special requirements of the prestressed steel strand. The experiment results show that fiber Bragg gratings can represent the overall stress of the prestressed steel strand without being affected by the specific structure of the strand when it is only fixed on one wire. It is also demonstrated that the maximum strain that …

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Novel Color Processing Architecture For Digital Cameras With Cmos Image Sensors, Chaminda Weerasinghe, Wanqing Li, Igor Kharitonenko, Magnus Nilsson, Sue Twelves Jan 2005

Novel Color Processing Architecture For Digital Cameras With Cmos Image Sensors, Chaminda Weerasinghe, Wanqing Li, Igor Kharitonenko, Magnus Nilsson, Sue Twelves

Faculty of Informatics - Papers (Archive)

This paper presents a color processing architecture for digital color cameras utilizing complementary metal oxide semiconductor (CMOS) image sensors. The proposed architecture gives due consideration to the peculiar aspects of CMOS image sensors and the human visual perception related to the particular application of digital color photography. A main difference between the proposed method arid the conventional systems is the fact that color correction module is located before the interpolation module. Therefore, a method of performing color correction on a color filter array (CFA) pattern is also provided in this paper. The interpolation algorithm is especially designed to solve the …

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Efficient Broadcast From Trapdoor Functions, Yi Mu, Willy Susilo, Xinyi Huang Jan 2005

Efficient Broadcast From Trapdoor Functions, Yi Mu, Willy Susilo, Xinyi Huang

Faculty of Informatics - Papers (Archive)

We present a novel scheme of broadcast encryption that is suitable for broadcast servers such as pay TV services. The important feature of our scheme is that the length of a broadcast string in our scheme is independent of the number of receivers in the system; hence it is suitable for large groups. Our scheme is based on a trapdoor encryption technique under the RSA assumption. We also describe a variant of our scheme which provides stronger security.

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Reducing Security Overhead For Mobile Networks, Fangguo Zhang, Yi Mu, Willy Susilo Jan 2005

Reducing Security Overhead For Mobile Networks, Fangguo Zhang, Yi Mu, Willy Susilo

Faculty of Informatics - Papers (Archive)

Security of mobile communications comes with the cost of computational overhead. Reducing the overhead in security computations is critical to ensure the overall performance of a mobile network. In this paper, we present the notion of online/offline signcryption, where most of computations are carried out offline and the online part of our scheme does not require any exponent computations and therefore is very efficient. Our scheme allows any third party to verify the encryption without compromising confidentiality. We also show that our scheme is secure against existential forgery under chosen message attacks and adaptively chosen ciphertext attacks under the notion …

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An Id-Based Access Control Scheme For Mospf, Junqi Zhang, Vijay Varadharajan, Yi Mu Jan 2005

An Id-Based Access Control Scheme For Mospf, Junqi Zhang, Vijay Varadharajan, Yi Mu

Faculty of Informatics - Papers (Archive)

Multicast Open Shortest Path First (MOSPF) is an enhancement to unicast routing protocol OSPF. It has been widely used in many multicast applications for years. However, its security is still a major concern in some applications. Much work has been done on data protection, but only a few works have been done on member access control mechanisms. In this paper, we present a new secure multicast architecture and protocol for MOSPF from the perspective of member access control. Our new model includes a variant of previous access control mechanism and a novel ID-based distributed encryption scheme. This architecture in particular …

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A Neural Network With Localized Receptive Fields For Visual Pattern Classification, Son Lam Phung, Abdesselam Bouzerdoum Jan 2005

A Neural Network With Localized Receptive Fields For Visual Pattern Classification, Son Lam Phung, Abdesselam Bouzerdoum

Faculty of Informatics - Papers (Archive)

We introduce a new neural network for 2D pattern classification. The new neural network, termed as localized receptive field neural network (RFNet), consists of a receptive field layer for 2D feature extraction, followed by one or more 1D feedforward layers for feature classification. All synaptic weights and biases in the network are automatically determined through supervised training. In this paper, we derive five different training methods for the RFNet, namely gradient descent, gradient descent with momentum, resilient backpropagation, Polak-Ribiere conjugate gradient, and Levenberg-Marquadrt algorithm. We apply the RFNet to classify face and nonface patterns, and study the performances of the …

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Scene Analysis For Autonomous System Control, David Ngan Luu, David A. Stirling Jan 2005

Scene Analysis For Autonomous System Control, David Ngan Luu, David A. Stirling

Faculty of Informatics - Papers (Archive)

The potential of autonomous airborne platforms have long been considered for applications in surveillance, exploration and search and rescue. For example, an autonomous blimp or airship, able to navigate through complex unstructured environments, could be used to survey the aftermath of dangerous earthquake zones, or be employed to provide unique replay angles in sporting events. Therefore autonomous airships fill an important gap in the spectrum of aerial observations, supplying images with better resolution and much more acquisition flexibility than those acquired through satellite or airplanes. This paper proposes to configure a semi-autonomous Unmanned Aerial Vehicle (UAV) for research into navigation …

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Copyright Protection Scheme For Digital Television Content, Prashan Premaratne, Liyanage C. Desilva, Farzad Safaei Jan 2005

Copyright Protection Scheme For Digital Television Content, Prashan Premaratne, Liyanage C. Desilva, Farzad Safaei

Faculty of Informatics - Papers (Archive)

We have developed a copyright protection system aimed at empowering the content provider to dictate the terms for free-to-air digital TV recording. The system proposes embedding copyright instructions into MPEG2 content to be telecasted so that the complying set top boxes would not be able to bypass the terms such as expiry period of recording or prohibition of recording of any specific program. After the expiration of the program recording rights, as determined by the telecaster, any recorded program is deleted. The system also uses encryption to prevent content copying to external storage devices.

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Implementation Of A Turbo Codes Test Bed In The Simulink Environment, Ibrahim S. Raad, Mehmet Yakan Jan 2005

Implementation Of A Turbo Codes Test Bed In The Simulink Environment, Ibrahim S. Raad, Mehmet Yakan

Faculty of Informatics - Papers (Archive)

This paper presents an implementation of turbo codes test bed developed in Matlab’s Simulink which will aid researchers in the field of turbo codes.It discusses the design, implementation and presents the validation results.

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A Watermarking Scheme In Low Frequency Components Using 2d Barcodes, Prashan Premaratne, Ian Burnett, Liyanage C. De Silva Jan 2005

A Watermarking Scheme In Low Frequency Components Using 2d Barcodes, Prashan Premaratne, Ian Burnett, Liyanage C. De Silva

Faculty of Informatics - Papers (Archive)

A robust watermark should be able to withstand most image manipulations such as cropping, additive noise and JPEG type compressions. It should also be able to hold telltale signs of attacks that are unknown to the user. Both of these aims can be fulfilled by embedding two watermarks, one fragile and one robust in different domains where watermarks are not vulnerable to the aforementioned manipulations. It is a well known fact that watermarking of DC components of discrete cosine transform (DCT) stand against JPEG compression. We build on this concept by inserting a watermark in the transform domain to further …

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Identity-Based Ring Signcryption Schemes: Cryptographic Primitives For Preserving Privacy And Authenticity In The Ubiquitous World, Xinyi Huang, Willy Susilo, Yi Mu, Futai Zhang Jan 2005

Identity-Based Ring Signcryption Schemes: Cryptographic Primitives For Preserving Privacy And Authenticity In The Ubiquitous World, Xinyi Huang, Willy Susilo, Yi Mu, Futai Zhang

Faculty of Informatics - Papers (Archive)

In this paper, we present a new concept called an identity based ring signcryption scheme (IDRSC,). We argue that this is an important cryptographic primitive that must be used to protect privacy and authenticity of a collection of users who are connected through an ad-hoc network, such as Bluetooth. We also present an efficient IDRSC scheme based on bilinear pairing. As a regular signcryption scheme, our scheme combines the functionality of signature and encryption schemes. However, the idea is to have an identity based system. In our scheme, a user can anonymously sign-crypts a message on behalf of the group. …

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Handwritten Digit Recognition Based On Shunting Inhibitory Convolutional Neural Networks, Fok Hing Chi Tivive, Abdesselam Bouzerdoum Jan 2005

Handwritten Digit Recognition Based On Shunting Inhibitory Convolutional Neural Networks, Fok Hing Chi Tivive, Abdesselam Bouzerdoum

Faculty of Informatics - Papers (Archive)

This paper presents the application of a new class of convolutional neural networks based on the mechanism of shunting inhibition for handwritten digit recognition. With a three layer network architecture and the use of shunting inhibitory neurons as information processing elements, the network consists of 1926 trainable parameters which are adapted by a first-order gradient training algorithm derived from Rprop, Quickprop, and SuperSAB. Trained on a dataset of 10,000 samples and evaluated on the entire test set of the MNIST database, these networks achieve classification accuracies above 93% with the best performance obtained from those networks with partial connection schemes.

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Privacy-Enhanced Internet Storage: Non-Interactive Publicly Verifiable 1-Out-Of-N Encryption Schemes, Willy Susilo, Fangguo Zhang, Yi Mu Jan 2005

Privacy-Enhanced Internet Storage: Non-Interactive Publicly Verifiable 1-Out-Of-N Encryption Schemes, Willy Susilo, Fangguo Zhang, Yi Mu

Faculty of Informatics - Papers (Archive)

One of the main important uses of Internet is its ability to connect people through the use of email or Internet storage. However, it is often desirable to limit the use of email or Internet storage due to organization's restriction, avoiding spams, etc. In particular, emails with multimedia contents will take up a lot of spaces. In this paper, we propose cryptographic schemes that can be used to stop unwanted messages to be stored in the Internet server. We refer this technique as privacy enhancement for Internet storage, since the Internet server will not learn any information directed to …

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Using Simcts Framework To Model Determinants Of Customer Satisfaction: A Case In An Isp, Karthik Vilapakkam Nagarajan, Meena Chavan, Tamrad Woldu Tewoldeberhan, Peter James Vial, V. N. Srivalli Jan 2005

Using Simcts Framework To Model Determinants Of Customer Satisfaction: A Case In An Isp, Karthik Vilapakkam Nagarajan, Meena Chavan, Tamrad Woldu Tewoldeberhan, Peter James Vial, V. N. Srivalli

Faculty of Informatics - Papers (Archive)

In this paper we describe a call center simulation case study that uses real data obtained from an Internet Service Provider (ISP). The case study is conducted using SIMCTS (Simulation Modelling and Analysis of Customer Satisfaction Patterns for Telecommunication Service Providers) framework [25]. The applicability of this framework to model ISP business scenario is discussed in detail. The simulation case study reveal that the dimensions of service quality have huge impact on customer satisfaction and also provide valuable insight in to gap analysis of customer perception and expectation. Various key satisfaction variables in relation to call center are modelled using …

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An Eye Feature Detector Based On Convolutional Neural Network, Fok Hing Chi Tivive, Abdesselam Bouzerdoum Jan 2005

An Eye Feature Detector Based On Convolutional Neural Network, Fok Hing Chi Tivive, Abdesselam Bouzerdoum

Faculty of Informatics - Papers (Archive)

One of the main problems when developing an eye detection and tracking system is to build a robust eye classifier that can detect the true eye patterns in complex scenes. This classi fication task is very challenging as the eye can appear in different locations with varying orientations and scales. Furthermore, the eye pattern varies intrinsically between ethnic groups, and with age and gender of a person. To cope better with these variations, we propose to use a bio-inspired convolutional neural network, based on the mechanism of shunting inhibition, for the detection of eye patterns in unconstrained environments. A learning …

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An Ultra Wide Band Simulator Using Matlab/Simulink, Peter James Vial, Beata J. Wysocki, Tad Wysocki Jan 2005

An Ultra Wide Band Simulator Using Matlab/Simulink, Peter James Vial, Beata J. Wysocki, Tad Wysocki

Faculty of Informatics - Papers (Archive)

Ultra Wide Band (UWB) is a promising technology for sensor networks, broadband wireless data access and location finding applications. This study outlines the development and validation of a single transmitter and receiver system across the multipath channel proposed by Saleh-Valenzuela. We have designed and tested a UWB simulator using MATLAB’s Simulink in combination with the Real Time Workshop(RTW) Tool box for Simulink using the Fixed Step Discrete Solvers of RTW which is required to produce executable simulations on multiple computers (both Linux and Microsoft based devices). This paper outlines the basic design and modules chosen for the simulation and compares …

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