Physical Sciences and Mathematics Commons^™

Dynamic Selection Of Service Peers With Multiple Property Specifications, Jun Shen, Shuai Yuan, Aneesh Krishna

Faculty of Informatics - Papers (Archive)

Semantic Web services, one of the most significant areas in the emerging business process management systems, have attracted a great deal of effort from both academic and industry community. Traditional methodologies are still very inadequate to effectively and autonomously conduct service discovery and composition in a dynamic environment, as they seldom focus on dealing with real complex situations, such as simultaneously considering peers’ multiple specifications which reflect different properties of e-services. Different ontology based e-service profiles have been proposed to enhance service oriented framework for the total or partial automation of service invocation, discovery, selection and composition, which are involved …

Towards Dynamic Formation Of Temporal Constraints For The Service Level Agreements Negotiation, Azlan Ismail, Jun Yan, Jun Shen

Faculty of Informatics - Papers (Archive)

SLAs play an important role for the QoS-driven service composition. Meanwhile, the temporal constraints are one of the main elements in the management of SLA especially in specifying the validity period of the QoS offers. In practice, the temporal constraints should be generated dynamically by taking the resource capability of the provider into account. The generation should consider various parameters that influence the resource capability such as the expected duration of the required Web service, the amount of current utilization, the amount of available resources, the number of required time slots, etc. Therefore, this paper aims to elaborate this issue …

E-Cheating And Calculator Technology: A Preliminary Study Into Casual Implications Of Calculator-Technology Usage On Students' Attitude Toward E-Cheating, Zeenath Khan

Faculty of Informatics - Papers (Archive)

Across the globe, educational institutions are adopting e-learning tools into their curricula to cater to the ever-growing demand for technology inside the classrooms. Where traditional blackboards have been replaced by virtual whiteboards and library books by online resources, teachers are trying hard to cope with the growing competition from technology outside the classroom that has captured their students’ attention and imagination, with more technology, perhaps increasing student dependency. However, the author’s previous research has shown that engaging e-learning tools to enhance student learning experience is not enough as it has negative impact on students’ attitude towards e-cheating, disillusioning their awareness …

Optimisation Of Component Sizes For A Hybrid Remote Area Power Supply System, Saad M. Sayeef, Nishad Mendis, Kashem Muttaqi

Faculty of Informatics - Papers (Archive)

In this paper, an optimisation model for determination of the optimal sizes of various system components, including wind, diesel and energy storage, has been developed to obtain a reliable and cost-effective wind-diesel hybrid remote area power supply (RAPS) system. A linear programming based cost minimisation algorithm has been formulated for determination of optimal sizes of various components in a RAPS system with consideration of continually varying wind and system load. The system constraints, including power balance for both under-generation and over-generation scenarios, have been considered in the optimisation formulation. Optimisation model to minimize the total cost of the system based …

Support Of Distribution System Using Distributed Wind And Pv Systems, Kai Zou, Ashish P. Agalgaonkar, Kashem Muttaqi, Sarath Perera, N Browne

Faculty of Informatics - Papers (Archive)

The application of renewable distributed generation (DG) could be considered as an alternative approach for distribution system expansion planning not only to reduce power loss and carbon emission, but also to improve system voltage profile. This paper investigates technical aspects relatedto voltage support and loss reduction in distribution systems with distributed wind and solar generation. The probabilistic wind, solar, and load models have been developed in order to address uncertain nature of wind speed, solar radiation, and load demand. Investigations have been carried out using Monte Carlo based probabilistic load flow analysis to estimate the probability distributions of system state …

Diffraction Of Ocean Waves Around A Hollow Cylindrical Shell Structure, Song-Ping Zhu, Lewis Mitchell

Faculty of Informatics - Papers (Archive)

In recent years, there has been renewed interest in problems of diffraction and radiation of ocean waves around structures, in relation to “green” power generation by Oscillating Water Column (OWC) devices. In this paper we present a first-order analytical solution for the diffraction of ocean waves around a hollow cylindrical shell structure suspended in an ocean of finite depth. By revisiting work done by Garrett (1970) on the problem of a bottomless harbor, but adopting a different and more direct method, we obtain the solution for the diffracted wave potential. Using the new approach, we analyze the dependence of the …

Comparison Of Alamouti And Sts Implementations Using A Software Defined Radio Test Bed, Shinhan Wee, Montserrat B. Ros, Peter James Vial

Faculty of Informatics - Papers (Archive)

A Software Defined Radio test bed using the Gnu Radio project was installed on Unix computers and modified so that estimates of the channel state coefficients were taken for a Multiple Input Multiple output (MIMO) system to take advantage of space time transmission at a frequency of 2.4GHz. Two MIMO techniques were implemented, one based on Alamouti and the other on Space Time Spreading. The technique used to estimate channel coefficients is described. The Bit Error Rate performance was compared, when using Binary Phase Shift Keying, between the two systems and it was found that the STS system performed better …

Application Of A Continuum Theory To Vertical Vibrations Of A Layer Of Granular Material, James M. Hill, Anthony J. Spencer, Scott W. Mccue

Faculty of Informatics - Papers (Archive)

Many interesting phenomena have been observed in layers of granular materials subjected to vertical oscillations; these include the formation of a variety of standing wave patterns, and the occurrence of isolated features called oscillons, which alternately form conical heaps and craters oscillating at one-half of the forcing frequency. No continuum-based explanation of these phenomena has previously been proposed. We apply a continuum theory, termed the double-shearing theory, which has had success in analyzing various problems in the flow of granular materials, to the problem of a layer of granular material on a vertically vibrating rigid base undergoing vertical oscillations in …

Reflecting On Ontologies Towards Ontology-Based Agent-Oriented Software Engineering, Ghassan Beydoun, Brian Henderson-Sellers, Jun Shen, G. Low

Faculty of Informatics - Papers (Archive)

“Ontology” in association with “software engineering” is becoming commonplace. This paper argues for the need to place ontologies at the centre of the software development lifecycle for multi agent systems to enhance reuse of software workproducts as well as to unify agent-based software engineering knowledge. The paper bridges the state-of-the-art of ontologies research from Knowledge Engineering (KE) within Artificial Intelligence and Metamodelling within Software Engineering (SE). It presents a sketch of an ontology-based Multi Agent System (MAS) methodology discussing key roles on ontologies and their impact of workproducts, illustrating these in a MAS software development project for an important application …

Is The Notion Of Divisible On-Line/Off-Line Signatures Stronger Than On-Line/Off-Line Signatures?, Willy Susilo, Yi Mu, Man Ho Allen Au

Faculty of Informatics - Papers (Archive)

On-line/Off-line signatures are useful in many applications where the signer has a very limited response time once the message is presented. The idea is to perform the signing process in two phases. The first phase is performed off-line before the message to be signed is available and the second phase is performed on-line after the message to be signed is provided. Recently, in CT-RSA 2009, Gao et al. made a very interesting observation that most of the existing schemes possess the following structure. In the off-line phase, a partial signature, called the off-line token is computed first. Upon completion of …

Secure Mobile Agents With Designated Hosts, Qi Zhang, Yi Mu, Minjie Zhang, Robert H. Deng

Faculty of Informatics - Papers (Archive)

Mobile agents often travel in a hostile environment where their security and privacy could be compromised by any party including remote hosts in which agents visit and get services. It was proposed in the literature that the host visited by an agent should jointly sign a service agreement with the agent's home, where a proxy-signing model was deployed and every host in the agent system can sign. We observe that this actually poses a serious problem in that a host that should be excluded from an underlying agent network could also send a signed service agreement. In order to solve …

Supply Current Charactersistics Of Modern Domestic Loads, Sean T. Elphick, Sarath Perera, Philip Ciufo

Faculty of Informatics - Papers (Archive)

The domestic load is considerably different to that seen 10 to 15 years ago. It has evolved significantly in terms of consumption and characteristics. In addition to traditional resistive and refrigeration type loads, the modern domestic load is now likely to contain a variety of sophisticated devices mostlypowered and controlled by power electronics. This paper examines the power quality characteristics of the modern domestic load. Laboratory testing and mathematical analysis is used to quantify and predict the behaviour of loads operating individually and in parallel. Specifically examined is thebehaviour and variation in harmonic current magnitudes across a variety of loads.

Voltage Quality Behaviour Of A Wind Turbine Based Remote Area Power System, Nishad Mendis, Kashem Muttaqi, Sarath Perera

Faculty of Informatics - Papers (Archive)

The power quality behaviour of a Remote Area Power System (RAPS) consisting of a Doubly Fed Induction Generator (DFIG), its main loads and a dummy load is presented in this paper. The dummy load is used to maintain the power balance of the system under changing wind and loading conditions. The performance of the remote area power system subject to various loading conditions has been evaluated in terms of the voltage quality, an aspect which has not received much attention in the past. The existing Distributed Generation (DG) power quality standards are taken as the basis to compare the voltage …

Computational Capabilities Of Graph Neural Networks, Franco Scarselli, Marco Gori, Ah Chung Tsoi, Markus Hagenbuchner, Gabriele Monfardini

Faculty of Informatics - Papers (Archive)

In this paper, we will consider the approximation properties of a recently introduced neural network model called graph neural network (GNN), which can be used to process-structured data inputs, e.g., acyclic graphs, cyclic graphs, and directed or undirected graphs. This class of neural networks implements a function tau(G, n) isin R ^m that maps a graph G and one of its nodes n onto an m-dimensional Euclidean space. We characterize the functions that can be approximated by GNNs, in probability, up to any prescribed degree of precision. This set contains the maps that satisfy a property …

Dynamic Service Selection For Service Composition With Time Constraints, Azlan Ismail, Jun Yan, Jun Shen

Faculty of Informatics - Papers (Archive)

Service selection is a kind of planning approach that evaluates and selects from multiple services to form a composite plan. In service selection, we found one additional issue that has not been investigated yet namely time constraints consistency among composite services. This issue is significant because there are potential time constraints involved that might cause inconsistency between selected services although they can offer aggregated QoS that satisfy global requirements. Furthermore, there might be some unintended waiting time to be considered in the QoS aggregation. Thus, this paper contributes to the analysis on the problem caused by the time constraints and …

Dynamic Modelling Of Hydroelectric Turbine-Generator Unit Connected To A Hvdc System For Small Signal Stability Analysis, Yin Chin Choo, Ashish P. Agalgaonkar, Kashem Muttaqi, Sarath Perera, Michael Negnevitsky

Faculty of Informatics - Papers (Archive)

This paper presents the linearised small-signal dynamic modelling of hydroelectric turbine-generator (TG) unit with CIGRE first high-voltage direct current (HVDC) benchmark system in the synchronously rotating D-Q reference frame for small-signal stability analysis. The interaction behaviour between the hydroelectric unit and the dynamics and control of HVDC system is investigated utilising eigen-analysis,participation factor analysis and by conducting sensitivity studies. The computation of eigenvalues and eigenvectors for small signal stability analysis provides an invaluable insight onto the power system dynamic behaviour by characterising the damping and frequency of the system oscillatory modes. Theconsequences of different operating conditions, such as active and …

Fuzzy Control For Nonlinear Uncertain Electrohydraulic Active Suspensions With Input Constraint, Haiping Du, Nong Zhang

Faculty of Informatics - Papers (Archive)

This paper presents a Takagi-Sugeno (T-S) model-based fuzzy control design approach for electrohydraulic active vehicle suspensions considering nonlinear dynamics of the actuator, sprung mass variation, and constraints on the control input. The T-S fuzzy model is first applied to represent the nonlinear uncertain electrohydraulic suspension. Then, a fuzzy state feedback controller is designed for the obtained T-S fuzzy model with optimized H _infin performance for ride comfort by using the parallel-distributed compensation (PDC) scheme. The sufficient conditions for the existence of such a controller are derived in terms of linear matrix inequalities (LMIs). Numerical simulations on a full-car suspension model …

Modelling Hydrogen Adsorption Within Spherical, Cylindrical And Slit-Shaped Cavities, Aaron Thornton, James M. Hill

Faculty of Informatics - Papers (Archive)

The ability to store hydrogen in a highly dense state within absorbents via the mechanism of adsorption has become a critical step in order to make a hydrogen powered automobile a practical reality. Absorbents are composed of nano-scale cavities (or pores) designed in such a way that hydrogen will adsorb onto the internal surface and thus be stored densely and safely enough for transport at ambient conditions. This work investigates the effect of the geometry of the cavity shape by applying a new mathematical model for predicting gas uptake, which is based on calculating the van der Waals' interactions for …

Analysis Of Property-Preservation Capabilities Of The Rox And Esh Hash Domain Extenders, Reza Reyhanitabar, Willy Susilo, Yi Mu

Faculty of Informatics - Papers (Archive)

Two of the most recent and powerful multi-property preserving (MPP) hash domain extension transforms are the Ramdom-Oracle-XOR (ROX) transform and the Enveloped Shoup (ESh) transform. The former was proposed by Andreeva et al. at ASIACRYPT 2007 and the latter was proposed by Bellare and Ristenpart at ICALP 2007. In the existing literature, ten notions of security for hash functions have been considered in analysis of MPP capabilities of domain extension transforms, namely CR, Sec, aSec, eSec (TCR), Pre, aPre, ePre, MAC, PRF, PRO. Andreeva et al. showed that ROX is able to preserve seven properties; namely collision resistance (CR), three …

A Car Detection System Based On Hierarchical Visual Features, Fok Hing Chi Tivive, Abdesselam Bouzerdoum

Faculty of Informatics - Papers (Archive)

In this paper, we address the problem of detecting and localizing cars in still images. The proposed car detection system is based on a hierarchical feature detector in which the processing units are shunting inhibitory neurons. To reduce the training time and complexity of the network, the shunting inhibitory neurons in the first layer are implemented as directional nonlinear filters, whereas the neurons in the second layer have trainable parameters. A multi-resolution processing scheme is implemented so as to detect cars of different sizes, and to reduce the number of false positives during the detection stage, an adaptive thresholding strategy …

Identifying Anatomical Shape Difference By Regularized Discriminative Direction, Luping Zhou, Richard Hartley, Lei Wang, Paulette Lieby, Nick Barnes

Faculty of Informatics - Papers (Archive)

Identifying the shape difference between two groups of anatomical objects is important for medical image analysis and computer-aided diagnosis. A method called ldquodiscriminative directionrdquo in the literature has been proposed to solve this problem. In that method, the shape difference between groups is identified by deforming a shape along the discriminative direction. This paper conducts a thorough study about inferring this discriminative direction in an efficient and accurate way. First, finding the discriminative direction is reformulated as a preimage problem in kernel-based learning. This provides a complementary but conceptually simpler solution than the previous method. More importantly, we find that …

Dynamic Universal Accumulators For Ddh Groups And Their Application To Attribute-Based Anonymous Credential Systems, Man Ho Au, Patrick P. Tsang, Willy Susilo, Yi Mu

Faculty of Informatics - Papers (Archive)

We present the first dynamic universal accumulator that allows (1) the accumulation of elements in a DDH-hard group G and (2) one who knows x such that y = g^x has - or has not - been accumulated, where g generates G, to efficiently prove her knowledge of such x in zero knowledge, and hence without revealing, e.g., x or y. We introduce the Attribute-Based Anonymous Credential System, which allows the verifier to authenticate anonymous users according to any access control policy expressible as a formula of possibly negated boolean user attributes. We construct the system from our accumulator.

Embedded Partially Replicated Designs For Grain Quality Testing, Alison B. Smith, Robin Thompson, Brian R. Cullis

Faculty of Informatics - Papers (Archive)

The literature on the design and analysis of cereal variety trials has focussed on the trait of grain yield. Such trials are also used to obtain information on grain quality traits but these are rarely subjected to the same level of statistical rigour. The data are often obtained using composite rather than individual replicate samples. This precludes the use of an efficient statistical analysis. In this paper we propose an approach in which a proportion of varieties is grain quality tested using individual replicate samples. This is achieved by embedding a partially replicated design (for measuring quality traits) within a …

Estimation In A Multiplicative Mixed Model Involving A Genetic Relationship Matrix, Alison M. Kelly, Brian R. Cullis, Arthur R. Gilmour, John A. Eccleston, Robin Thompson

Faculty of Informatics - Papers (Archive)

Genetic models partitioning additive and non-additive genetic effects for populations tested in replicated multi-environment trials (METs) in a plant breeding program have recently been presented in the literature. For these data, the variance model involves the direct product of a large numerator relationship matrix A, and a complex structure for the genotype by environment interaction effects, generally of a factor analytic (FA) form. With MET data, we expect a high correlation in genotype rankings between environments, leading to non-positive definite covariance matrices. Estimation methods for reduced rank models have been derived for the FA formulation with independent genotypes, and we …

Effects Of Novel Hybrid And Traditional Rootstocks On Vigour And Yield Components Of Shiraz Grapevines, T H. Jones, B R. Cullis, P R. Clingeleffer, E H. Ruhl

Faculty of Informatics - Papers (Archive)

Background and Aims: The influence of grapevine rootstocks on vine vigour and crop yield is recognized as an integral part of viticultural management. However, the genetic potential of Vitis species rootstock hybrids for vigour and yield control is not fully exploited in Australian viticulture. The effect of 55 novel inter- and intra-species hybrids and five traditional hybrid rootstock cultivars on winter pruning weight, berry size and fruit yield of grafted Shiraz vines is presented. The genetic predictions that resulted from this analysis were used to illustrate how rootstocks that best perform for a combination of traits may be selected.

Methods …

A Part-Based Template Matching Method For Multi-View Human Detection, Duc Thanh Nguyen, Wanqing Li, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

This paper proposes a part-based template matching method for multi-view human detection. The proposed method includes two stages: matching and verification. In particular, the best individual matching parts given a detection window are determined using an improved template matching algorithm. The hypothesis of the matched parts forming a human is then verified by employing a Bayesian-based model. The verification is not only based on the matching costs of individual parts but also how well the combining the matched parts satisfying the configuration constraints of the human body. Experimental results have shown that the proposed method is robust for detecting humans …

A Novel Template Matching Method For Human Detection, Duc Thanh Nguyen, Wanqing Li, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

This paper proposes a novel weighted template matching method. It employs a generalized distance transform (GDT) and an orientation map (OM). The GDT allows us to weight the distance transform more on the strong edge points and the OM provides supplementary local orientation information for matching. Based on the matching method, a two-stage human detection method consisting of template matching and Bayesian verification is developed. Experimental results have shown that the proposed method can effectively reduce the false positive and false negative detection rates and perform superiorly in comparison to the conventional Chamfer matching method.

Human Detection Based On Weighted Template Matching, Duc Thanh Nguyen, Philip Ogunbona, Wanqing Li

Faculty of Informatics - Papers (Archive)

This paper proposes a new two-stage human detection method involving matching and verification. A Bayesian framework is developed to verify the matching score obtained from a weighted distance measure. Performance evaluation indicates that the proposed method is able to utilize the flexible matching scheme and produce superior true positive, true negative and low misclassification rates.

Greedy Approximation Of Kernel Pca By Minimizing The Mapping Error, Peng Cheng, Wanqing Li, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

In this paper we propose a new kernel PCA (KPCA) speed-up algorithm that aims to find a reduced KPCA to approximate the kernel mapping. The algorithm works by greedily choosing a subset of the training samples that minimizes the mean square error of the kernel mapping between the original KPCA and the reduced KPCA. Experimental results have shown that the proposed algorithm is more efficient in computation and effective with lower mapping errors than previous algorithms.

Kernel Pca Of Hog Features For Posture Detection, Peng Cheng, Wanqing Li, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

Motivated by the non-linear manifold learning ability of the Kernel Principal Component Analysis (KPCA), we propose in this paper a method for detecting human postures from single images by employing KPCA to learn the manifold span of a set of HOG features that can effectively represent the postures. The main contribution of this paper is to apply the KPCA as a non-linear learning and open-set classification tool, which implicitly learns a smooth manifold from noisy data that scatter over the feature space. For a new instance of HOG feature, its distance to the manifold that is measured by its reconstruction …