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Full-Text Articles in Science and Technology Studies
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 …
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 …
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.
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.
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, …
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 …
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 …
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 …
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.
Network Structure, Ict Use And Performance Attitudes Of Knowledge Workers, Kon Shing Kenneth Chung, Liaquat Hossain
Network Structure, Ict Use And Performance Attitudes Of Knowledge Workers, Kon Shing Kenneth Chung, Liaquat Hossain
Faculty of Engineering and Information Sciences - Papers: Part A
In this study, we examine the effect of social network structure and information and communication technologies (ICT) use on performance attitudes of knowledge-intensive workers in dispersed occupational communities. We first develop a theoretical framework and use it to develop a valid and reliable survey instrument. Secondly, we apply structural hole measures (constraint and efficiency) for exploring the association with ICT use and attitudes to performance. Empirical results suggest that density of knowledge workers' professional network is positively associated with ICT use whereas network efficiency is negatively correlated with ICT use at both task and communication-structure level. The findings show that …
Single- And Multi-Carrier Idma Schemes With Cyclic Prefixing And Zero Padding Techniques, Qinghua Guo, Xiaojun Yuan, Li Ping
Single- And Multi-Carrier Idma Schemes With Cyclic Prefixing And Zero Padding Techniques, Qinghua Guo, Xiaojun Yuan, Li Ping
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, we investigate single-carrier (SC) and multi-carrier IDMA schemes with cyclic prefixing (CP) and zero padding (ZP) techniques. These schemes are called SC-IDMA-CP, SC-IDMA-ZP, orthogonal frequency-division multiplexing (OFDM)-IDMA-CP and OFDM-IDMA-ZP, respectively. By exploiting the circulant property of channel matrices, the multi-user detection of these schemes can be efficiently realised with per-user complexity independent of the number of users and the length of inter-symbol interference (ISI) channels. We show the potential advantages of ZP-based schemes in power efficiency and convergence speed. Simulation results are provided to compare the four schemes. Copyright © 2008 John Wiley & Sons, Ltd.
Lmmse Turbo Equalization Based On Factor Graphs, Qinghua Guo, Li Ping
Lmmse Turbo Equalization Based On Factor Graphs, Qinghua Guo, Li Ping
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, a vector-form factor graph representation is derived for intersymbol interference (ISI) channels. The resultant graphs have a tree-structure that avoids the short cycle problem in existing graph approaches. Based on a joint Gaussian approximation, we establish a connection between the LLR (log-likelihood ratio) estimator for a linear system driven by binary inputs and the LMMSE (linear minimum mean-square error) estimator for a linear system driven by Gaussian inputs. This connection facilitates the application of the recently proposed Gaussian message passing technique to the cycle-free graphs for ISI channels. We also show the equivalence between the proposed approach …
Evolution Analysis Of Low-Cost Iterative Equalization In Coded Linear Systems With Cyclic Prefixes, Xiaojun Yuan, Qinghua Guo, Xiaodong Wang, Li Ping
Evolution Analysis Of Low-Cost Iterative Equalization In Coded Linear Systems With Cyclic Prefixes, Xiaojun Yuan, Qinghua Guo, Xiaodong Wang, Li Ping
Faculty of Engineering and Information Sciences - Papers: Part A
This paper is concerned with the low-cost iterative equalization/detection principles for coded linear systems with cyclic prefixes. Turbo frequency-domain-equalization (FDE) is applied to systems that may contain the joint effect of multiple-access interference (MAI), cross-antenna interference (CAI) and inter-symbol interference (ISI). We develop an SNK-variance evolution technique for the performance evaluation of the proposed systems. Numerical results in various channel environments demonstrate excellent agreement between the predicted and simulated system performance. © 2008 IEEE.
Impact Of Signaling Schemes On Iterative Linear Minimum-Mean-Square-Error Detection, Li Ping, Jun Tong, Xiaojun Yuan, Qinghua Guo
Impact Of Signaling Schemes On Iterative Linear Minimum-Mean-Square-Error Detection, Li Ping, Jun Tong, Xiaojun Yuan, Qinghua Guo
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, we study the iterative detection problem for a coded system with multi-ary modulation. We show that, with iterative linear minimum-mean-square-error (LMMSE) detection, superposition coded modulation (SCM) can provide performance superior to that with other traditional signaling schemes used in trellis coded modulation (TCM) and bit-interleaved coded modulation (BICM). This finding provides a useful guideline for system design considering inter-symbol interference (ISI) and other forms of interference. Simulation results are provided to illustrate the efficiency of the iterative LMMSE detection with different signaling schemes. © 2008 IEEE.
Joint Linear Interleaver Design For Concatenated Zigzag Codes, D S. Lin, S Tong, S Q. Li
Joint Linear Interleaver Design For Concatenated Zigzag Codes, D S. Lin, S Tong, S Q. Li
Faculty of Engineering and Information Sciences - Papers: Part A
The design of a class of well-structured low-density parity-check (LDPC) codes, namely linear interleaver based concatenated zigzag (LICZ) codes, is investigated. With summary distances as the design metric, short LICZ codes with large minimum distances can be constructed. Moreover, an efficient cycle-based method is proposed to compute the minimum distances of LICZ codes. Simulation results show that LICZ codes outperform both CZ codes with random interleavers and LDPC codes by the progressive edge growth algorithm.
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.
Performance Analysis Of Multi-Ary Systems With Iterative Linear Minimum-Mean-Square-Error Detection, Li Ping, Jun Tong, Xiaojun Yuan, Qinghua Guo
Performance Analysis Of Multi-Ary Systems With Iterative Linear Minimum-Mean-Square-Error Detection, Li Ping, Jun Tong, Xiaojun Yuan, Qinghua Guo
Faculty of Engineering and Information Sciences - Papers: Part A
This paper is concerned with coded multi-ary systems over linear channels. Based on a semi-analytical evolution technique, the impact of signaling schemes on the performance of low-cost iterative linear minimum-mean-square-error (LMMSE) detection is studied. It is shown that superposition coded modulation (SCM) maximizes the output signal-to-noise ratio (SNR) of LMMSE detectors. Consequently, SCM may potentially outperform other conventional signaling schemes when LMMSE detectors are used. Numerical examples are provided to verify the theoretical analysis. © 2008 IEEE.
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 …
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 …
An Analysis Of The Criteria For Evaluating Adequate Theories Of Computation, Nir Fresco
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 malfunctions), the taxonomy criterion (i.e. distinguishing between different classes …
Laterally Loaded Rigid Piles In Cohesionless Soil, Wei-Dong Guo
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
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 …
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.
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 …
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 …
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, …