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Full-Text Articles in Social and Behavioral Sciences
She-Pwm Switching Strategies For Active Neutral Point Clamped Multilevel Converters, Sridhar R. Pulikanti, Mohamed S. A Dahidah, Vassilios G. Agelidis
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 …
Semifinite Spectral Triples Associated With Graph C*-Algebras, Alan L. Carey, John Phillips, Adam Rennie
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.
Gas Drainage Improvement In Underground Coal Mines, Dennis John Black, Naj Aziz
Gas Drainage Improvement In Underground Coal Mines, Dennis John Black, Naj Aziz
Faculty of Engineering and Information Sciences - Papers: Part A
Effective gas management is vital to the success of the longwall mining in the Bulli seam, in the Southern Coalfield, Sydney Basin, NSW, Australia. The evolution of gas drainage methods and practices are discussed with respect to gas type, gas drainage lead time and prevailing geological conditions. Both underground to inseam drilling and surface to inseam drilling techniques are described at both pre and post-drainage conditions. Post-drainage of gas from longwall is discussed for its effectiveness, practicability and efficiency. The long term benefit of the method selected is examined with respect to gas capture efficiency. An alternative method of surface …
Hydraulic Fracturing In Underground Coal Mines, Dennis John Black, Naj Aziz
Hydraulic Fracturing In Underground Coal Mines, Dennis John Black, Naj Aziz
Faculty of Engineering and Information Sciences - Papers: Part A
The success of hydraulic fracturing application in stimulating gas drainage from coal seams is influenced by the ground stress conditions and the effective installation of straddled packers. A total of five holes were drilled in the Bulli Seam in a mine (Mine A) and tested for increased gas stimulation by hydraulic fracturing. Parameters examined included casing material integrity for cutability and ability to resist the external collapse during grouting and hydraulic fracturing. Changes made to the injecti on pressure, casing wall thickness, slot orientation (circumferential instead of axial) and controlled pressure release rate post-treatment improved the hydraulic fracturing treatment. However, …
The Evolution In Coal Mine Gas Extraction - A Response To Economic, Environmental And Community Pressures, Dennis John Black, Naj Aziz
The Evolution In Coal Mine Gas Extraction - A Response To Economic, Environmental And Community Pressures, Dennis John Black, Naj Aziz
Faculty of Engineering and Information Sciences - Papers: Part A
Effective gas management is vital to the success of the longwall mines operating in the Bulli seam, located in the Southern Sydney Basin, Australia. High gas emissions are characteristic of the region with specific gas emissions typically in the order of 30-45 m3/t. The mines that operate in this area have, since 1980, relied on the use of extensive underground to inseam (UIS) drilling to drain gas both ahead of advancing roadway development and following longwall coal extraction. With the ever increasing production capacity of modern mining machinery the UIS methods are struggling to drain sufficient gas from the coal …
Improving Uis Gas Drainage In Underground Coal Mines, Dennis John Black, Naj Aziz
Improving Uis Gas Drainage In Underground Coal Mines, Dennis John Black, Naj Aziz
Faculty of Engineering and Information Sciences - Papers: Part A
Gas drainage is considered one of the most effective controls in preventing coal and gas outbursts. The advances in mining equipment technology over the last 20 years have led to a significant increase in coal mine production, resulting in increased coal mine gas emission during the coal extraction process. High gas emissions, if not effectively managed, may exceed the diluting capability of the mine's ventilation system, potentially exceeding the statutory limit, resulting in gas related production delays. The development of underground to inseam (UIS) gas drainage is discussed. The study is focused on a range of factors which impact gas …
Development Of Hydraulic Fracturing In High Stress Conditions In Australian Underground Coal Mines, Dennis John Black, Naj Aziz
Development Of Hydraulic Fracturing In High Stress Conditions In Australian Underground Coal Mines, Dennis John Black, Naj Aziz
Faculty of Engineering and Information Sciences - Papers: Part A
Hydraulic fracturing has been used extensively in the petroleum and coalbed methane industries as a means of improving access to the reservoir and thereby enhancing production. In the Australian coal mining industry there has been an aversion to the use of hydraulic fracturing. One of the main reasons for the lack of application of this technology has been the perceived risk of damage to the strata and the resulting impact on future mining operations. A number of Australian mines are progressing toward areas where gas drainage is becoming increasingly difficult and these mines are seriously considering the use of hydraulic …
Distributed Generation Diversity Level For Optimal Investment Planning, An D. T Le, M A. Kashem, Michael Negnevitsky, G Ledwich
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
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
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
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 …
Shi's Local Estimates, Glen Wheeler
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
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
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.
Fitting Position Latent Cluster Models For Social Networks With Latentnet, Pavel N. Krivitsky, M Handcock
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
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
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.
Numerical Analysis Of Roll Deflection For Sendzimir Mill, H L. Yu, X H. Liu, G T. Lee, X W. Li, H D. Park
Numerical Analysis Of Roll Deflection For Sendzimir Mill, H L. Yu, X H. Liu, G T. Lee, X W. Li, H D. Park
Faculty of Engineering and Information Sciences - Papers: Part A
The present work introduces a new type of numerical analyzing method: the contact element method with two relative coordinates (CEM). The main characteristic of the procedure is elements meshing on the basis of the contact length between objects and that each element has two relative coordinates. The ordinary expression of this procedure is DX[CXY(i)]=D Y[CYX(i)]. Through this method, the CEM function of the 20-high Sendzimir mill and the deflection function expression of every roll are obtained. A computational software SM4SM for the Sendzimir mill has been developed, by which the deflection condition of rolls S, O, I, and A can …
Analysis Of Roll Gap Pressure In Sendzimir Mill By Fem, Hai-Liang Yu, Xiang-Hua Liu, Chao Wang, Hae-Doo Park
Analysis Of Roll Gap Pressure In Sendzimir Mill By Fem, Hai-Liang Yu, Xiang-Hua Liu, Chao Wang, Hae-Doo Park
Faculty of Engineering and Information Sciences - Papers: Part A
The acting force on the roll system of Sendzimir mill was analyzed using 3D FEM. The roll gap pressure distribution and the acting force between rolls S and O, rolls O and I, rolls O and J, rolls I and A, rolls I and B, as well as rolls J and B were analyzed. The results showed that the roll gap pressure mainly affected the roll surface layer, 50 mm for backup rolls the roll gap pressure distribution is of double peaks among the work roll, the 1st intermediate roll (IMR), and the 2nd IMR; the maximum value of the …
Formal Security Definition And Efficient Construction For Roaming With A Privacy-Preserving Extension, Guomin Yang, Duncan S. Wong, Xiaotie Deng
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
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 coalition …
Reducing Diffusible Hydrogen Contents Of Shielded Metal Arc Welds Through Addition Of Flux-Oxidizing Ingedients, John Du Plessis, Madeleine Du Toit
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 weld …
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
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.
A Novel Dynamic Absorber Using Enhanced Magnetorheological Elastomers For Powertrain Vibration Control, Nong Zhang, Nga Hoang, Haiping Du
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 property …
Cost-Based Bdi Plan Selection For Change Propagation, Khanh Hoa Dam, Michael Winikoff
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
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
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
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 …
Orbifolds Are Not Commutative Geometries, Adam C. Rennie, Joseph C. Varilly
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.
The Chern Character Of Semifinite Spectral Triples, Alan L. Carey, John Phillips, Adam C. Rennie, Fyodor A. Sukochev
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 residue cocycle, …