Physical Sciences and Mathematics Commons^™

Improving Bdd Cryptosystems In General Lattices, Willy Susilo, Thomas Plantard, Michael Rose

Dr Thomas Plantard

No abstract provided.

On The Cca-1 Security Of Somewhat Homomorphic Encryption Over The Integers, Zhenfei Zhang, Thomas Plantard, Willy Susilo

Dr Thomas Plantard

The notion of fully homomorphic encryption is very important since it enables many important applications, such as the cloud computing scenario. In EUROCRYPT 2010, van Dijk, Gentry, Halevi and Vaikuntanathan proposed an interesting fully homomorphic encryption scheme based on a somewhat homomorphic encryption scheme using integers. In this paper, we demonstrate a very practical CCA-1 attack against this somewhat homomorphic encryption scheme. Given a decryption oracle, we show that within O(λ2) queries, we can recover the secret key successfully, where λ is the security parameter for the system.

Processing Resource Scheduling In Programmable Networks, Farzad Safaei, D. Platt, Sanjay Jha, F. Sabrina, Cong Duc Nguyen

Dr Donald Platt

No abstract provided.

An Application Of The 5-S Activity Theoretic Requirements Method, Robert Brown, Peter Hyland, Ian Piper

Dr Ian Piper

One of the most crucial aspects of highly interactive, multi-user, organisational systems is the interface. The Human Computer Interaction (HCI) community has not adopted rigorous Formal Methods with open arms (Paterno, 1996). However, the HCI community has widely adopted Usability Engineering approaches (Corporate Solutions 2006), such as Nielsen’s (1994), which offers considerable formality. There remains, however, scope for user interface (UI) design to adopt a theoretical framework to enhance consistency across the whole design and development lifecycle. A theoretically-consistent framework from initial conceptual elicitation to evaluation of the finished product may prove useful. Since the aim of UI design is …

A Fundamental Analysis Of Continuous Flow Bioreactor And Membrane Reactor Models With Non-Competitive Product Inhibition. Ii. Exponential Inhibition, Mark Nelson, Wei Xian Lim

Associate Professor Mark Nelson

The steady-state production of a product produced through the growth of microorganisms in a continuous flow bioreactor is presented. A generalised reactor model is used in which both the classic well-stirred bioreactor and the idealised membrane bioreactor are considered as special cases. The reaction is assumed to be governed by Monod growth kinetics subject to non-competitive product inhibition. Inhibition is modelled as a decaying exponential function of the product concentration. This reaction scheme is well documented in the literature, although a stability analysis of the governing equations has not previously been presented. The performance of a well-stirred bioreactor with microorganisms …

Experience With Change Evaluations Suggests The Need For Better Learning Designs: One Possibility For Mathematics, Bothaina Bukhatowa, Anne Porter, Mark Nelson

Associate Professor Mark Nelson

A Change Evaluation was conducted in the School of Mathematics and Applied Statistics, at the University of Wollongong (UOW) with a view to identifying which resources to improve in order to facilitate better student learning outcomes. One hundred and thirty students took the subject MATH151 during the autumn term of the 2010 academic year with 101 students responding to the evaluation questionnaire. Data collection was used to discover which resources had the greatest potential for improvement or replacement and to examine if the structure of the subject could be improved for better student understanding and learning. The survey was also …

Analysis Of A Chemostat Model With Variable Yield Coefficient: Contois Kinetics., Rubayyi Alqahtani, Mark Nelson, Annette Worthy

Associate Professor Mark Nelson

Food processing wastewaters and slurries typically contain high concentrations of biodegradable organic matter. Before the wastewater can be discharged, the pollutant concentration must be reduced. One way to achieve this is by using a biological species (biomass) that consumes the organic matter (substrate). We investigate an unstructured kinetic model for a bioreactor with a variable yield coefficient, taking into account the death rate of the microorganisms. The growth rate is given by a Contois expression, which is often used to model the growth of biomass in wastewaters containing biodegradable organic materials. The analysis shows that the system has natural oscillations …

Survey Of Experimental Work On The Self-Heating And Spontaneous Combustion Of Coal, Mark Nelson, Xiao Dong Chen

Associate Professor Mark Nelson

No abstract provided.

A Mathematical Model For The Biological Treatment Of Industrial Wastewaters In A Cascade Of Four Reactors, Annette Worthy, Mark Nelson, Rubayyi Turki Alqahtani

Associate Professor Mark Nelson

Many industrial processes, particularly in the food industry, produce slurriesor wastewaters containing high concentrations of biodegradable organicmaterials. Before these contaminated wastewaters can be dischargedthe concentration of these pollutants must be reduced. A method which has beenextensively employed to remove biodegradable organic matter is biologicaltreatment. In this process the wastewater (or slurry) is passed through abioreactor containing biomass which grows through consumption of thepollutants.The industrial treatment of wastewaters typically employs a reactor cascade.In a reactor cascade of n reactors the effluent stream from the ith reactor inthe cascade acts as the feed stream for the (i+1)th reactor, i.e. the nextreactor. The …

Behaviour Of An Elementary Oxidation Reaction In A Semi-Batch Reactor, Mark Nelson, Harvinder Sidhu

Associate Professor Mark Nelson

No abstract provided.

A Two Dimensional, Reaction-Diffusion Model Of Compost Piles, T Luangwilai, H Sidhu, M Nelson

Associate Professor Mark Nelson

We consider the self heating process in a two dimensional spatially dependent model of a compost pile which incorporates terms that account for self heating due to both biological and oxidation mechanisms. As moisture is a crucial factor in both the degradation process and spontaneous ignition within a compost pile, this model consists of four mass-balance equations, namely, energy, oxygen, vapour and liquid water concentrations. Analyses are undertaken for different initial water contents within the compost pile. We show that when the water content is too low, the reaction is almost negligible; whereas when it is too high, the reaction …

A Fundamental Analysis Of Continuous Flow Bioreactor Models And Membrane Reactor Models To Process Industrial Wastewaters, Mark Nelson, Xiao Dong Chen, Easwaran Balakrishnan, Harvinder Sidhu

Associate Professor Mark Nelson

No abstract provided.

A Fundamental Analysis Of Continuous Flow Bioreactor Models With Recycle Around Each Reactor Governed By Contois Kinetics. Iii. Two And Three Reactor Cascades, Rubayyi Alqahtani, Mark Nelson, Annette Worthy

Associate Professor Mark Nelson

The steady-state treatment of industrial wastewaters in a cascade reactor with recycle is analyzed. A number of cascades with alternative arrangements of the settling units are considered. Specifically, we consider the case when the recycle stream leaving a settling unit which is placed around a reactor goes back into the feed stream for that reactor. The Contois kinetic model is used to study the degradation of biodegradable organic materials. The steady-states for the model are found and their stability determined as a function of the total residence time in the cascade. Asymptotic solutions in the limit of large total residence …

A Mathematical Model For The Biological Treatment Of Industrial Wastewater In A Reactor Cascade, Rubayyi Turki Alqahtani, Mark Nelson, Annette Worthy

Associate Professor Mark Nelson

Many industrial processes, particularly in the food industry, produce slurries or wastewaters containing high concentrations of biodegradable organic materials. Before these contaminated wastewaters can be discharged the concentration of the biodegradable organic pollutant must be reduced. One way to do this is to pass the wastewater through a bioreactor containing biomass which grows through consumption of the pollutant. Anaerobic conditions are often favoured for the processing of waste materials with high levels of biodegradable organic pollutants as these can be removed with low investment and operational costs. We investigate the steady state effluent concentration leaving a cascade of two reactors. …

A Spatially Uniform Model Of Oxidative Self-Heating In Compost Piles, Mark Nelson, Xiao Dong Chen, Harvinder Sidhu

Associate Professor Mark Nelson

In this paper we model the thermal behaviour of compost heaps in the presence of micro-organism undergoing oxidative exothermic reactions. For simplicity we consider a spatially uniform model in which oxidative reactions of the cellulosic components is ignored. We use singularity theory to investigate the generic properties of the model. We show that there are two generic steady-state diagrams including one in which the temperature-response curve is the standard S-shaped curve familiar from combustion problems. Such a steady-state diagram contains an elevated temperature branch, which is the feature of practical interest in facilities such as industrial compost heaps and municipal …

Theoretical Probing Of The Phenomenon Of The Formation Of The Outermost Surface Layer Of A Multi-Component Particle, And The Surface Chemical Composition After The Rapid Removal Of Water In Spray Drying, Mark Nelson, Harvinder Sidhu, X.D. Chen

Associate Professor Mark Nelson

Spray drying is a primary process for the manufacture of powders, which satisfy a vast array of societal demands in the areas of nutrition, health and medicine. The functionality of a spray-dried product begins with its incorporation into water (wetting followed by dispersion) Therefore, as its surface chemical composition and structure determine its first contact with water (that is, its hydrophilic nature), these are of prime concern. Laboratory studies on this first layer, which is in the order of several nm in depth from the surface, have been extensive but there is still a lack of a fundamental quantitative explanation …

Mathematical Analysis Of Self-Heating In Compost Piles, Harvinder Sidhu, Mark Nelson, Nadeem Ansari, Xiao Dong Chen

Associate Professor Mark Nelson

We model the increase in temperature in compost piles or landfill sites due to micro-organisms undergoing exothermic reactions. The model incorporates the heat release due to biological activity within the pile and the heat release due to the oxidation of cellulosic materials. The heat release rate due to biological activity is modelled by a function which is a monotonic increasing function of temperature over a particular range and followed by a monotone decreasing function of temperature. This functionality represents the fact that micro-organisms die or become dormant at high temperatures. The heat release due to the oxidation reaction is modelled …

Tempestites In A Teapot? Condensation-Generated Shell Beds In The Upper Ordovician, Cincinnati Arch, Usa, Benjamin F. Dattilo

Benjamin F. Dattilo

Skeletal concentrations in mudstones may represent local facies produced by storm winnowing in shallow water, or time-specific deposits related to intervals of diminished sediment supply. Upper Ordovician (Katian) of the Cincinnati region is a mixed siliciclastic-carbonate succession including meter-scale cycles containing a shelly limestone-dominated phase and a mudstone-dominated phase.

The “tempestite proximality model” asserts that shell-rich intervals originated by winnowing of mud from undifferentiated fair-weather deposits. Thus shell beds are construed as tempestites, while interbedded mudstones represent either fair-weather or bypassed mud. Meter-scale cycles are attributed to sea-level fluctuation or varying storm intensity.

Alternatively, the “episodic starvation model” argues, on …

A Novel Solution To The Millionaire Problem, Yi Mu, Luke Mcaven, Shuo Zheng

Dr Luke McAven

We give an efficient symmetric--key based protocol to solve Yao'smillionaire problem. We assume a semi--honest server assists incomparing values held by two different parties. We assume thisserver only executes the protocol precisely and does not colludewith any other participants. We protect the participants against theserver getting any information about the numbers or theirrelationship, by using encryption and hash chains. The protocol hasthree communication phases; initialisation, computation andannouncement. Each of the two parties and the server sends twomessages during the protocol. Each phase requires the two parties torun one of their three algorithms. We discuss the correctness,security properties and efficiency of …

Viewpoint Invariants From Three-Dimensional Data: The Role Of Reflection In Human Activity Understanding, Ramakrishna Kakarala, Prabhu Kaliamoorthi, Wanqing Li

Associate Professor Wanqing Li

Human activity understanding from three-dimensional data, such as from depth cameras, requires viewpoint-invariant matching. In this paper, we propose a new method of constructing invariants that allows distinction between isometries based on rotation, which preserve handedness, and those that involve reflection, which reverse right and left hands. The state-of-the-art in viewpoint invariants uses either global descriptors such as moments or spherical harmonic magnitudes, or relies on local methods such as feature matching. None of those methods are able to easily distinguish rotations from reflections, which is essential to understand left vs right handed gestures. We show that the distinction between …

Mri Reconstruction From 2d Truncated K-Space, Jianhua Luo, Yuemin Zhu, Wanqing Li, Pierre Croisille, Isabelle Magnin

Associate Professor Wanqing Li

Purpose: To shorten acquisition time by means of both partial scanning and partial echo acquisition and to reconstruct images from such 2D partial k-space acquisitions. Materials and Methods: We propose an approach to reconstructing magnetic resonance images from 2D truncated k-space in which the k-space is truncated in both phase- and frequency-encoding directions. Unlike conventional reconstruction techniques, the proposed approach is based on a newly developed 2D singularity function analysis (SFA) model and a sparse representation of an image whose parameters can be estimated from the 2D partial k-space data. Such a sparse representation leads to an accurate recovery of …

Semi-Supervised Maximum A Posteriori Probability Segmentation Of Brain Tissues From Dual-Echo Magnetic Resonance Scans Using Incomplete Training Data, Wanqing Li, P Ogunbona, C Desilva, Y Attikiouzel

Associate Professor Wanqing Li

This study presents a stochastic framework in which incomplete training data are used to boost the accuracy of segmentation and to optimise segmentation when images under consideration are corrupted by inhomogeneities. The authors propose a semi-supervised maximum a posteriori probability (ssMAP) segmentation method that is able to utilise any amount of training data that are usually insufficient for supervised segmentation. The ssMAP unifies supervised and unsupervised segmentation and takes the two as its special cases. To deal with inhomogeneities, the authors propose to incorporate a bias field into the ssMAP and present an algorithm (referred to as ssMAPe) for simultaneous …

Face To Face Communications In Multiplayer Online Games: A Real-Time System, Ce Zhan, Wanqing Li, Farzad Safaei, Philip Ogunbona

Associate Professor Wanqing Li

Multiplayer online games (MOG) bring HCI into a new era of human-human interactions in computer world. Although current MOG provide more interactivity and social interaction in the virtual world, natural facial expression as a key factor in emulating face to face communications has been neglected by game designers. In this work, we propose a real-time automatic system to recognize players’ facial expressions, so that the recognition results can be used to drive the MOG’s “facial expression engine” instead of “text commands”. Our major contributions are the evaluation, improvement and efficient implementation of existing algorithms to build a real-time system that …

Human Detection With Contour-Based Local Motion Binary Patterns, Duc Thanh Nguyen, Philip Ogunbona, Wanqing Li

Associate Professor Wanqing Li

This paper presents a human detection method using contour- based local motion features. The local motion is encoded using a variant of the popular Local Binary Pattern (LBP) called Non-Redundant Local Binary Pattern (NRLBP) descriptor computed on the difference image of two consecutive frames. In addition, the local motion features are extracted along the human's boundary contour. Localising features on the contours has the advantage of utilizing a precise human shape description. A motivation of the proposed method is that most of informative movements are performed on boundary contours of the body parts, e.g. legs of pedestrians. Evaluation of the …

Human Motion Simulation And Action Corpus, Gang Zheng, Wanqing Li, Philip Ogunbona, Liju Dong, Igor Kharitonenko

Associate Professor Wanqing Li

Acquisition of large scale good quality training samples is becoming a major issue in machine learning based human motion analysis. This paper presents a method to simulate continuous gross human body motion with the intention to establish a human motion corpus for learning and recognition. The simulation is achieved by a temporal-spatialtemporal decomposition of human motion into actions, joint actions and actionlets based on the human kinematic model. The actionlet models the primitive moving phase of a joint and represents the muscle movement governed by kinesiological principles. Joint actions and body actions are constructed from actionlets through constrained concatenation and …

Smoke Detection In Videos Using Non-Redundant Local Binary Pattern-Based Features, Hongda Tian, Wanqing Li, Philip Ogunbona, Duc Thanh Nguyen, Ce Zhan

Associate Professor Wanqing Li

This paper presents a novel and low complexity method for real-time video-based smoke detection. As a local texture operator, Non-Redundant Local Binary Pattern (NRLBP) is more discriminative and robust to illumination changes in comparison with original Local Binary Pattern (LBP), thus is employed to encode the appearance information of smoke. Non-Redundant Local Motion Binary Pattern (NRLMBP), which is computed on the difference image of consecutive frames, is introduced to capture the motion information of smoke. Experimental results show that NRLBP outperforms the original LBP in the smoke detection task. Furthermore, the combination of NRLBP and NRLMBP, which can be considered …

Illumination Invariant Face Detection Using Classifier Fusion, Alister Cordiner, Philip Ogunbona, Wanqing Li

Associate Professor Wanqing Li

An approach to the problem of illumination variations in face detection that uses classifier fusion is presented. Multiple face detectors are seperately trained for different illumination environments and their results are combined using a combination rule. To define the illumination environments, the training samples are clustered based on their illumination using unsupervised training. Different methods of clustering the samples and combining the outputs of the classifiers are examined. Experiments with the AR face database show that the proposed method achieves higher accuracy than the traditional monolithic face detection method.

Optimal Image Watermark Decoding, Wenming Lu, Wanqing Li, Reihaneh Safavi-Naini, Philip Ogunbona

Associate Professor Wanqing Li

Not much has been done in utilizing the available information at the decoder to optimize the decoding performance of watermarking systems. This paper focuses on analyzing different decoding methods, namely, Minimum Distance, Maximum Likelihood and Maximum a-posteriori decoding given varying information at the decoder in the blind detection context. Specifically, we propose to employ Markov random fields to model the prior information given the embedded message is a structured logo. The application of these decoding methods in Quantization Index Modulation systems shows that the decoding performance can be improved by Maximum Likelihood decoding that exploits the property of the attack …

A Novel Video-Based Smoke Detection Method Using Image Separation, Hongda Tian, Wanqing Li, Lei Wang, Philip Ogunbona

Associate Professor Wanqing Li

In the state-of-the-art video-based smoke detection methods, the representation of smoke mainly depends on the visual information in the current image frame. In the case of light smoke, the original background can be still seen and may deteriorate the characterization of smoke. The core idea of this paper is to demonstrate the superiority of using smoke component for smoke detection. In order to obtain smoke component, a blended image model is constructed, which basically is a linear combination of background and smoke components. Smoke opacity which represents a weighting of the smoke component is also defined. Based on this model, …

Image Reconstruction From Sparse Projections Using S-Transform, Jianhua Luo, Jiahai Liu, Wanqing Li, Yuemin Zhu, Ruiyao Jiang

Associate Professor Wanqing Li

Sparse projections are an effective way to reduce the exposure to radiation during X-ray CT imaging. However, reconstruction of images from sparse projection data is challenging. This paper introduces a new sparse transform, referred to as S-transform, and proposes an accurate image reconstruction method based on the transform. The S-transform effectively converts the ill-posed reconstruction problem into a well-defined one by representing the image using a small set of transform coefficients. An algorithm is proposed that efficiently estimates the S-transform coefficients from the sparse projections, thus allowing the image to be accurately reconstructed using the inverse S-transform. The experimental results …