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Full-Text Articles in Social and Behavioral Sciences

Formal Security Definition And Efficient Construction For Roaming With A Privacy-Preserving Extension, Guomin Yang, Duncan S. Wong, Xiaotie Deng Jan 2008

Formal Security Definition And Efficient Construction For Roaming With A Privacy-Preserving Extension, Guomin Yang, Duncan S. Wong, Xiaotie Deng

Faculty of Engineering and Information Sciences - Papers: Part A

In a secure roaming scenario, a user U travels to a foreign network and communicates with a foreign server V securely so that no one other than U and V can obtain the messages exchanged between them. U may also want to travel anonymously so that no one including V can find out its identity or trace its whereabouts except its home server H. There have been many key establishment protocols proposed for secure roaming. A typical application of these protocols is the mobile roaming service which may be deployed to interconnected WLAN and 3G networks. Despite the importance of ...


A Best-First Anytime Algorithm For Computing Optimal Coalition Structures, Chattrakul Sombattheera, Aditya K. Ghose Jan 2008

A Best-First Anytime Algorithm For Computing Optimal Coalition Structures, Chattrakul Sombattheera, Aditya K. Ghose

Faculty of Engineering and Information Sciences - Papers: Part A

This work presents a best-first anytime algorithm for computing optimal coalition structures. The approach is novel in that it generates coalition structures based on coalition values, while existing algorithms base their generation on the structure (members and configurations) of coalitions. With our algorithm, coalition structures are generated by repeatedly choosing the best coalition, as determined using a novel metric called agent's contribution to coalition structure that we define. We have compared the performance of our algorithm against that of Rahwan et al [5] using 20 data distributions. Our results show that our algorithm almost always converges on an optimal ...


Reducing Diffusible Hydrogen Contents Of Shielded Metal Arc Welds Through Addition Of Flux-Oxidizing Ingedients, John Du Plessis, Madeleine Du Toit Jan 2008

Reducing Diffusible Hydrogen Contents Of Shielded Metal Arc Welds Through Addition Of Flux-Oxidizing Ingedients, John Du Plessis, Madeleine Du Toit

Faculty of Engineering and Information Sciences - Papers: Part A

This investigation examined the feasibility of using flux modification in the form of the addition of oxidizing ingredients to reduce the as-deposited hydrogen content of basic-type shielded metal arc welds. Additions of up to 16.3% micaceous iron oxide (MIO) to the flux formulation of an E7018-1 type electrode lowered the diffusible weld hydrogen content by approximately 70%. This can be attributed to the formation of oxygen, which lowers the partial pressure of hydrogen in the arc atmosphere, and the reaction of FeO (formed on dissociation of MIO) with hydrogen. The partitioning of deoxidizing elements (manganese and silicon) between the ...


Study Of The Energy Performance Of Korean Apartment Buildings With Alternative Balcony Configurations, Jo Clarke, Cameron Johnstone, Jaemin Kim, Georgios Kokogiannakis, Paul Strachan, Kyung-Hun Woo, Boo-Sik Kang Jan 2008

Study Of The Energy Performance Of Korean Apartment Buildings With Alternative Balcony Configurations, Jo Clarke, Cameron Johnstone, Jaemin Kim, Georgios Kokogiannakis, Paul Strachan, Kyung-Hun Woo, Boo-Sik Kang

Faculty of Engineering and Information Sciences - Papers: Part A

The purpose of this study is to evaluate the impact of the new regulations design changes on heating loads of apartment buildings and identify the construction configurations (e.g. glazing types, thermal properties, window area ratio, etc.) of the new designs that will ensure the energy performance is at least on the same level as those with a traditional balcony configuration.


Shi's Local Estimates, Glen Wheeler Jan 2008

Shi's Local Estimates, Glen Wheeler

Faculty of Engineering and Information Sciences - Papers: Part A

The talk is concerned with some of the analytic results and techniques that are fundamental to the study of the qualitative behavior of solutions of the Ricci flow, later used in singularity analysis. In particular we focus on derivatives estimates, useful for proving long time existence of solutions and obtaining local control of solutions.


Perelman's L-Distrance, V.-M Wheeler Jan 2008

Perelman's L-Distrance, V.-M Wheeler

Faculty of Engineering and Information Sciences - Papers: Part A

This talk is a preparation of the necessary tools for proving the non-collapsing results. The L-length defined by Perelman is the analog of an energy path, but defined in a Riemannian manifold context. The length is used to define the l reduced distance and later on, the reduced volume. So far the properties of the l-length have two applications in the proof of the Poincare conjecture. Associated with the notion of reduced volume, they are used to prove non-collapsing results and also to study the K- solutions.


Monotonicity Of Reduced Volume; Local Non-Collapsing, V.-M Wheeler Jan 2008

Monotonicity Of Reduced Volume; Local Non-Collapsing, V.-M Wheeler

Faculty of Engineering and Information Sciences - Papers: Part A

The talk is divided in two parts. In the first one we give the definition of the reduced volume and by means of reduced length we prove it to be non-increasing in backwards time.


Distributed Generation Diversity Level For Optimal Investment Planning, An D. T Le, M A. Kashem, Michael Negnevitsky, G Ledwich Jan 2008

Distributed Generation Diversity Level For Optimal Investment Planning, An D. T Le, M A. Kashem, Michael Negnevitsky, G Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

The task of improving the supply quality and maintaining supply continuity during emergencies has become more feasible for a distribution company (DISCO), owing to new developments in Distributed Generation (DG) technologies. Even though the technical issues regarding DG interconnection to the main grid are of great importance and are being addressed by on-going research, it must be clearly placed in the context of on the financial performance of the utility. In this paper, a general approach to quantify the technical benefits of DG employment is proposed. The power system economic impact is assessed by evaluating supply quality, supply reliability, system ...


Differential Equations And Asymptotic Solutions For Arithmetic Asian Options: 'Black-Scholes Formulae' For Asian Rate Calls, Jeffrey Dewynne, William Shaw Jan 2008

Differential Equations And Asymptotic Solutions For Arithmetic Asian Options: 'Black-Scholes Formulae' For Asian Rate Calls, Jeffrey Dewynne, William Shaw

Faculty of Engineering and Information Sciences - Papers: Part A

In this article, we present a simplified means of pricing Asian options using partial differential equations (PDEs). We first provide a concise derivation of the well-known similarity reduction and exact Laplace transform solution. We then analyse the problem afresh as a power series in the volatility-scaled contract duration, with a view to obtaining an asymptotic solution for the low-volatility limit, a limit which presents difficulties in the context of the general Laplace transform solution. The problem is approached anew from the point of view of asymptotic expansions and the results are compared with direct, high precision, inversion of the Laplace ...


Berkovich Indentation Of Diamondlike Carbon Coatings On Silicon Substrates, Ayesha J. Haq, Paul Munroe, Mark Hoffman, Phil Martin, Avi Bendavid Jan 2008

Berkovich Indentation Of Diamondlike Carbon Coatings On Silicon Substrates, Ayesha J. Haq, Paul Munroe, Mark Hoffman, Phil Martin, Avi Bendavid

Faculty of Engineering and Information Sciences - Papers: Part A

The deformation behavior of diamondlike carbon (DLC) coatings on silicon substrates induced by Berkovich indentation has been investigated. DLC coatings deposited by a plasma-assisted chemical vapor deposition technique were subjected to nanoindentation with a Berkovich indenter over a range of maximum loads from 100 to 300 mN. Distinct pop-ins were observed for loads greater than 150 mN. However, no pop-out was observed for the loads studied. The top surface of the indents showed annular cracks with associated fragmented material. The cross sections showed up to 20% localized reduction in thickness of the DLC coating beneath the indenter tip. Cracking, {111 ...


Enhancing Information Flow In A Retail Supply Chain Using Rfid And The Epc Network: A Proof-Of-Concept Approach, Samuel Fosso Wamba, Harold Boeck Jan 2008

Enhancing Information Flow In A Retail Supply Chain Using Rfid And The Epc Network: A Proof-Of-Concept Approach, Samuel Fosso Wamba, Harold Boeck

Faculty of Engineering and Information Sciences - Papers: Part A

RFID technology and the Electronic Product Code (EPC) network have attracted considerable interest from businesses and academics in recent years. The interest is even stronger in the retail industry where firms such as Best Buy, Wal-Mart, Tesco, Target and Metro AG are capitalizing on the potential of these technologies. Based on a field study conducted in a three-layer retail supply chain, this paper tests several scenarios integrating Radio Frequency Identification (RFID) technology and the EPC network and evaluates, in a laboratory setting, their potential as enablers of information flow within a retail supply chain. Using an "open-loop" adoption strategy, our ...


An Analysis Of The Criteria For Evaluating Adequate Theories Of Computation, Nir Fresco Jan 2008

An Analysis Of The Criteria For Evaluating Adequate Theories Of Computation, Nir Fresco

Faculty of Engineering and Information Sciences - Papers: Part A

This paper deals with the question: What are the criteria that an adequate theory of computation has to meet? (1) Smith's answer: it has to meet the empirical criterion (i.e. doing justice to computational practice), the conceptual criterion (i.e. explaining all the underlying concepts) and the cognitive criterion (i.e. providing solid grounds for computationalism). (2) Piccinini's answer: it has to meet the objectivity criterion (i.e. identifying computation as a matter of fact), the explanation criterion (i.e. explaining the computer's behaviour), the right things compute criterion, the miscomputation criterion (i.e. accounting for ...


Laterally Loaded Rigid Piles In Cohesionless Soil, Wei-Dong Guo Jan 2008

Laterally Loaded Rigid Piles In Cohesionless Soil, Wei-Dong Guo

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, limiting force profile for laterally loaded rigid piles in sand and is differentiated from the on-pile force profile, from which elastic-plastic solutions are established and presented in explicity expressioins. Nonlinear responses of the piles are characterized by slip depths mobilized from mudline and the pile-tip. At the states of tip-yield and rotation point yield, expressions for some critical depths are developed, which allow the on-pile force profiles to be constructed. The solutions and the expressions are developed concerning a constant subgrade modulus (k) and a linearly incresing modulus with depth (Gibson k), respectively. capitalized on three measurable ...


Two Colour Nonlocal Vector Solitary Waves With Angular Momentum In Nematic Liquid Crystals, Gaetano Assanto, Noel F. Symth, A. L. Worthy Jan 2008

Two Colour Nonlocal Vector Solitary Waves With Angular Momentum In Nematic Liquid Crystals, Gaetano Assanto, Noel F. Symth, A. L. Worthy

Faculty of Engineering and Information Sciences - Papers: Part A

The propagation and interaction of two solitary waves with angular momentum in bulk nematic liquid crystals, termed nematicons, have been studied in the nonlocal limit. These two spinning solitary waves are based on two different wavelengths of light and so are referred to as two-color nematicons. Under suitable boundary conditions, the two nematicons can form a bound state in which they spin about each other. This bound state is found to be stable to the emission of diffractive radiation as the nematicons evolve. In addition this bound state shows walk-off due to dispersion. Using an approximate method based on the ...


Fitting Position Latent Cluster Models For Social Networks With Latentnet, Pavel N. Krivitsky, M Handcock Jan 2008

Fitting Position Latent Cluster Models For Social Networks With Latentnet, Pavel N. Krivitsky, M Handcock

Faculty of Engineering and Information Sciences - Papers: Part A

latentnet is a package to fit and evaluate statistical latent position and cluster models for networks. Hoff, Raftery, and Handcock (2002) suggested an approach to modeling networks based on positing the existence of an latent space of characteristics of the actors. Relationships form as a function of distances between these characteristics as well as functions of observed dyadic level covariates. In latentnet social distances are represented in a Euclidean space. It also includes a variant of the extension of the latent position model to allow for clustering of the positions developed in Handcock, Raftery, and Tantrum (2007). The package implements ...


Fabrication And Characterisation Of Periodically Poled Lithium Niobate Waveguide Using Femtosecond Laser Pulses, Shuanggen Zhang, Jianghong Yao, Qing Shi, Yange Liu, Weiwei Liu, Zhangchao Huang, Fuyun Lu, Enbang Li Jan 2008

Fabrication And Characterisation Of Periodically Poled Lithium Niobate Waveguide Using Femtosecond Laser Pulses, Shuanggen Zhang, Jianghong Yao, Qing Shi, Yange Liu, Weiwei Liu, Zhangchao Huang, Fuyun Lu, Enbang Li

Faculty of Engineering and Information Sciences - Papers: Part A

We present in this letter the fabrication and characterization of thermally stable type II waveguides in Z-cut periodically poled lithium niobate crystals. The waveguides were fabricated by using a femtosecond laser and were utilized for second harmonic generation. Our experiments have shown that a quasiphase matching wavelength of 1548.2nm, a tuning bandwidth of 2nm, and a tuning temperature range of 150.4±1.6°C can be achieved.


High Spatial Resolution Fibre -Optic Fizeau Interferometric Strain Sensor Based On An In-Fiber Spherical Microcavity, Enbang Li, Gang-Ding Peng, Xin Ding Jan 2008

High Spatial Resolution Fibre -Optic Fizeau Interferometric Strain Sensor Based On An In-Fiber Spherical Microcavity, Enbang Li, Gang-Ding Peng, Xin Ding

Faculty of Engineering and Information Sciences - Papers: Part A

We present a fiber-optic Fizeau interferometric strain sensor consisting of an in-fiber spherical microcavity of 39um in diameter. The spherical microcavity was formed by splicing a normal single-mode fiber with a hollow-core photonic crystal fiber. We demonstrate that strain sensing can be realized by using the interference between the light signals reflected by the front and rear surfaces of the sphere. Experiments have shown that the strain sensor has a strain sensitivity of 3.36um/ue and a temperature sensitivity of 1.35um/°C.


Tangential Sphere Bounds On The Ensemble Performance Of Ml Decoded Gallager Codes Via Their Exact Ensemble Distance Spectrum, Sheng Tong Jan 2008

Tangential Sphere Bounds On The Ensemble Performance Of Ml Decoded Gallager Codes Via Their Exact Ensemble Distance Spectrum, Sheng Tong

Faculty of Engineering and Information Sciences - Papers: Part A

An efficient numerical approach to the exact ensemble distance spectrum of Gallager codes has been developed by evaluating powers of polynomials. With the exact ensemble distance spectrum of Gallager codes, tangential sphere upper bounds on their maximum likelihood (ML) decoding performance over binary input AWGN channels are investigated. Numerical results indicate improved bounds have been obtained, better than Sason and Shamai's results (which are based on Gallager's upper bound on the ensemble distance spectrum), especially in the error floor region. Furthermore, some critical properties of Gallager codes, including typical minimum distance and the performance tradeoff in the waterfall ...


Thermal And Electrical Characterization Of Silicon Photomultiplier, M Petasecca, B Alpat, G Ambrosi, P Azzarello, R Battiston, M Ionica, A Papi, G U. Pignatel, S Haino Jan 2008

Thermal And Electrical Characterization Of Silicon Photomultiplier, M Petasecca, B Alpat, G Ambrosi, P Azzarello, R Battiston, M Ionica, A Papi, G U. Pignatel, S Haino

Faculty of Engineering and Information Sciences - Papers: Part A

Detection of low levels of light is one of the key aspects in medical and space applications. Silicon photomultiplier, a novel type of avalanche photodetector which operates in Geiger mode, shows promising results and offer superior design options. The performance characteristics of the SiPM realized in FBK-irst are studied and presented in this paper. The leakage current, dark rate and internal gain are characterized as a function of temperature. The investigation has been carried out in the framework of the DASiPM Collaboration and the INFN/FBK-irst MEMS project. © 2008 IEEE.


A Novel Dynamic Absorber Using Enhanced Magnetorheological Elastomers For Powertrain Vibration Control, Nong Zhang, Nga Hoang, Haiping Du Jan 2008

A Novel Dynamic Absorber Using Enhanced Magnetorheological Elastomers For Powertrain Vibration Control, Nong Zhang, Nga Hoang, Haiping Du

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a novel Adaptive Tuned Vibration Absorber (ATVA) using the enhanced magnetorheological elastomers (MREs) for powertrain vibration reduction. The MRE material used in this application includes micro-sized iron particles enhanced by adding nano-sized magnetic powders. With the enhancement, MRE's elastic modulus significantly increases due to the MR effect. In the new ATVA, the MRE plays a role as a torsional spring whose stiffness coefficient can be varied with an external magnetic field. Additionally, this ATVA could operate in shear-squeeze mode rather than shear mode. Thus, the frequency range is much wider than that of general MREs. Such ...


She-Pwm Switching Strategies For Active Neutral Point Clamped Multilevel Converters, Sridhar R. Pulikanti, Mohamed S. A Dahidah, Vassilios G. Agelidis Jan 2008

She-Pwm Switching Strategies For Active Neutral Point Clamped Multilevel Converters, Sridhar R. Pulikanti, Mohamed S. A Dahidah, Vassilios G. Agelidis

Faculty of Engineering and Information Sciences - Papers: Part A

The main drawback of the diode neutral-point-clamped (NPC) converter is the unequal loss distribution among the semiconductor devices which confines the maximum output power and the switching frequency. To address this drawback, switching state redundancy is required to evenly distribute the losses and can be achieved differently as the level of the converter changes. For instance, the three-level active NPC (3L-ANPC) converter has switching state redundancy and is derived from the 3L-NPC converter by adding an anti-parallel switch to the clamping diodes; in the 4L-ANPC converter, the combination of a 2L converter and a 3L-ANPC converter is used; in a ...


Cost-Based Bdi Plan Selection For Change Propagation, Khanh Hoa Dam, Michael Winikoff Jan 2008

Cost-Based Bdi Plan Selection For Change Propagation, Khanh Hoa Dam, Michael Winikoff

Faculty of Engineering and Information Sciences - Papers: Part A

Software maintenance is responsible for as much as two thirds of the cost of any software, and is consequently an important research area. In this paper we focus on the change propagation problem: given a primary change that is made in order to meet a new or changed requirement, what additional, secondary, changes are needed? We build on previous work that has proposed to use a BDI (belief-desire-intention) agent framework to propagate changes by fixing violations of consistency constraints. One question that needs to be answered as part of this framework is how to select between different applicable (repair) plan ...


An Agent-Oriented Approach To Support Change Propagation In Software Evolution, Hoa K. Dam Jan 2008

An Agent-Oriented Approach To Support Change Propagation In Software Evolution, Hoa K. Dam

Faculty of Engineering and Information Sciences - Papers: Part A

Software maintenance and evolution is arguably a lengthy and expensive phase in the life cycle of a software system. A critical issue at this phase is change propagation: given a set of primary changes that have been made to software, what additional secondary changes are needed? Although many approaches have been proposed, automated change propagation is still a significant technical challenge in software maintenance and evolution. This paper presents a Ph.D. research in the final stages of developing and evaluating a novel, agent-based, framework to support semi-automated change propagation in evolving software systems.


A Kernel-Induced Space Selection Approach To Model Selection Of Klda, Lei Wang, Kap Luk Chan, Ping Xue, Luping Zhou Jan 2008

A Kernel-Induced Space Selection Approach To Model Selection Of Klda, Lei Wang, Kap Luk Chan, Ping Xue, Luping Zhou

Faculty of Engineering and Information Sciences - Papers: Part A

Model selection in kernel linear discriminant analysis (KLDA) refers to the selection of appropriate parameters of a kernel function and the regularizer. By following the principle of maximum information preservation, this paper formulates the model selection problem as a problem of selecting an optimal kernel-induced space in which different classes are maximally separated from each other. A scatter-matrix-based criterion is developed to measure the "goodness" of a kernel-induced space, and the kernel parameters are tuned by maximizing this criterion. This criterion is computationally efficient and is differentiable with respect to the kernel parameters. Compared with the leave-one-out (LOO) or -fold ...


Adaboost With Svm-Based Component Classifiers, Xuchun Li, Lei Wang, Eric Sung Jan 2008

Adaboost With Svm-Based Component Classifiers, Xuchun Li, Lei Wang, Eric Sung

Faculty of Engineering and Information Sciences - Papers: Part A

The use of SVM (Support Vector Machine) as component classifier in AdaBoost may seem like going against the grain of the Boosting principle since SVM is not an easy classifier to train. Moreover, Wickramaratna et al. [2001. Performance degradation in boosting. In: Proceedings of the Second International Workshop on Multiple Classifier Systems, pp. 11-21] show that AdaBoost with strong component classifiers is not viable. In this paper, we shall show that AdaBoost incorporating properly designed RBFSVM (SVM with the RBF kernel) component classifiers, which we call AdaBoostSVM, can perform as well as SVM. Furthermore, the proposed AdaBoostSVM demonstrates better generalization ...


The Chern Character Of Semifinite Spectral Triples, Alan L. Carey, John Phillips, Adam C. Rennie, Fyodor A. Sukochev Jan 2008

The Chern Character Of Semifinite Spectral Triples, Alan L. Carey, John Phillips, Adam C. Rennie, Fyodor A. Sukochev

Faculty of Engineering and Information Sciences - Papers: Part A

In previous work we generalised both the odd and even local index formula of Connes and Moscovici to the case of spectral triples for a ∗-subalgebra A of a general semifinite von Neumann algebra. Our proofs are novel even in the setting of the original theorem and rely on the introduction of a function valued cocycle (called the resolvent cocycle) which is 'almost' a (b,B)-cocycle in the cyclic cohomology of A. In this paper we show that this resolvent cocycle 'almost' represents the Chern character, and assuming analytic continuation properties for zeta functions, we show that the associated ...


Orbifolds Are Not Commutative Geometries, Adam C. Rennie, Joseph C. Varilly Jan 2008

Orbifolds Are Not Commutative Geometries, Adam C. Rennie, Joseph C. Varilly

Faculty of Engineering and Information Sciences - Papers: Part A

In this note we show that the crucial orientation condition for commutative geometries fails for the natural commutative spectral triple of an orbifold M/G.


Psdboost: Matrix-Generation Linear Programming For Positive Semidefinite Matrices Learning, Chunhua Shen, Alan Welsh, Lei Wang Jan 2008

Psdboost: Matrix-Generation Linear Programming For Positive Semidefinite Matrices Learning, Chunhua Shen, Alan Welsh, Lei Wang

Faculty of Engineering and Information Sciences - Papers: Part A

In this work, we consider the problem of learning a positive semidefinite matrix. The critical issue is how to preserve positive semidefiniteness during the course of learning. Our algorithm is mainly inspired by LPBoost [1] and the general greedy convex optimization framework of Zhang [2]. We demonstrate the essence of the algorithm, termed PSDBoost (positive semidefinite Boosting), by focusing on a few different applications in machine learning. The proposed PSDBoost algorithm extends traditional Boosting algorithms in that its parameter is a positive semidefinite matrix with trace being one instead of a classifier. PSDBoost is based on the observation that any ...


Regularized Discriminative Direction For Shape Difference Analysis, Luping Zhou, Richard Hartley, Lei Wang, Paulette Lieby, Nick Barnes Jan 2008

Regularized Discriminative Direction For Shape Difference Analysis, Luping Zhou, Richard Hartley, Lei Wang, Paulette Lieby, Nick Barnes

Faculty of Engineering and Information Sciences - Papers: Part A

The "discriminative direction" has been proven useful to re- veal the subtle difference between two anatomical shape classes. When a shape moves along this direction, its deformation will best manifest the class difference detected by a kernel classifier. However, we observe that such a direction cannot maintain a shape's "anatomical" correctness, in- troducing spurious difference. To overcome this drawback, we develop a regularized discriminative direction by requiring a shape to conform to its population distribution when it deforms along the discriminative direction. Instead of iterative optimization, an analytic solution is pro- vided to directly work out this direction. Experimental ...


Semifinite Spectral Triples Associated With Graph C*-Algebras, Alan L. Carey, John Phillips, Adam Rennie Jan 2008

Semifinite Spectral Triples Associated With Graph C*-Algebras, Alan L. Carey, John Phillips, Adam Rennie

Faculty of Engineering and Information Sciences - Papers: Part A

We review the recent construction of semifinite spectral triples for graph C^*-algebras. These examples have inspired many other developments and we review some of these such as the relation between the semifinite index and the Kasparov product, examples of noncommutative manifolds, and an index theorem in twisted cyclic theory using a KMS state.