Open Access. Powered by Scholars. Published by Universities.®
Social and Behavioral Sciences Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 31 - 49 of 49
Full-Text Articles in Social and Behavioral Sciences
Psdboost: Matrix-Generation Linear Programming For Positive Semidefinite Matrices Learning, Chunhua Shen, Alan Welsh, Lei Wang
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
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 study …
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 …
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 …
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 …
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 …
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.
A Low-Complexity Iterative Channel Estimation And Detection Technique For Doubly Selective Channels, Qinghua Guo, Li Ping
A Low-Complexity Iterative Channel Estimation And Detection Technique For Doubly Selective Channels, Qinghua Guo, Li Ping
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, we propose a low-complexity iterative joint channel estimation, detection and decoding technique for doubly selective channels. The key is a segment-by-segment frequency domain equalization (FDE) strategy under the assumption that channel is approximately static within a short segment. Guard gaps (for cyclic prefixing or zero padding) are not required between adjacent segments, which avoids the power and spectral overheads due to the use of cyclic prefix (CP) in the conventional FDE technique. A low-complexity bi-directional channel estimation algorithm is also developed to exploit correlation information of time-varying channels. Simulation results are provided to demonstrate the efficiency of …
Implementing Analytical Geometric And Penetration Response Correction For Keel-Edge Pinhole Spect Image Reconstruction, Xuezhu Zhang, Qiusheng Dai, Yujin Qi
Implementing Analytical Geometric And Penetration Response Correction For Keel-Edge Pinhole Spect Image Reconstruction, Xuezhu Zhang, Qiusheng Dai, Yujin Qi
Faculty of Engineering and Information Sciences - Papers: Part A
The collimator response compensation is very important in high-resolution pinhole SPECT imaging for resolution recovery and quantitative imaging. In this study the pinhole collimator response of the keel-edge aperture was investigated in terms of the geometric response function and penetration response function (GPRF). An approximate numerical method was proposed to implement the geometric and penetration response correction (GPRC) for keel-edge pinhole SPECT image reconstruction. A lookup table for the GPRC was calculated and then was utilized in the 3D pinhole iterative OSEM reconstruction procedure. The performance of the image reconstruction with the GPRC was evaluated using both the phantom and …
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 …
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} …
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 …
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.
Low-Complexity Iterative Detection In Multi-User Mimo Isi Channels, Xiaojun Yuan, Qinghua Guo, Li Ping
Low-Complexity Iterative Detection In Multi-User Mimo Isi Channels, Xiaojun Yuan, Qinghua Guo, Li Ping
Faculty of Engineering and Information Sciences - Papers: Part A
We propose a low-cost detection strategy for multi-user multiple-input-multiple-output (MIMO) systems with inter-symbol interference (ISI). The cyclic prefix (CP) technique is assumed. The proposed detection algorithm is derived in a very concise manner based on some elegant properties of circulant matrices. We show that multi-user detection and equalization can be carried out jointly and efficiently. © 2007 IEEE.
On Generalization Of Constitutive Models From Two Dimensions To Three Dimensions, N Khalili, M D. Liu
On Generalization Of Constitutive Models From Two Dimensions To Three Dimensions, N Khalili, M D. Liu
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, a study is made of the generalization of constitutive models for geomaterials from two-dimensional stress and strain states to three-dimensional stress and strain states. Existing methods of model generalization are reviewed and their deficiencies are highlighted. A new method is proposed based on geometries of the model imprints on two normal planes. Using the proposed method, various three dimensional failure criterions suitable for geomaterials are implemented directly into a two dimensional model and the generalized model is identical to its original form for the axially symmetric condition. To demonstrate the application of the proposed method, the Modified …
Performance Analysis Of Ofdm-Idma Systems With Peak-Power Limitation, Jun Tong, Qinghua Guo, Li Ping
Performance Analysis Of Ofdm-Idma Systems With Peak-Power Limitation, Jun Tong, Qinghua Guo, Li Ping
Faculty of Engineering and Information Sciences - Papers: Part A
This paper is concerned with orthogonal frequency-division multiplexing interleave-division multiple-access (OFDM-IDMA) systems over frequency-selective fading channels. Deliberate clipping is applied to reduce the peak-to-average power ratio (PAPR) of each user's transmitted signal. An iterative multiuser detection (MUD) technique is developed to recover the performance loss due to clipping. A semi-analytical signal-to- noise ratio (SNR) evolution technique is proposed, which can provide quick and accurate prediction of the iterative MUD performance. Numerical results show that the performance of OFDM-IDMA is not sensitive to the frequency selectivity of channels, and OFDM-IDMA is more power-efficient than other alternative multi-carrier transmission techniques. © 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 and error …
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
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.