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Articles 31 - 49 of 49
Full-Text Articles in Social and Behavioral Sciences
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 …
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.
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 …
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 …
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} …
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.
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.
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 …
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 …
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 …
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.
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.