676 research outputs found
Half-Dimension Subspace Decomposition for Fast Direction Finding With Arbitrary Linear Arrays
No full textIt is well-known that the multiple signal classification (MUSIC) algorithm is computationally time-consuming because it requires a complex-valued full-dimension eigenvalue decomposition (EVD) and a complex-valued spectral searching. In this paper, we exploit the virtual signal model of forward/backward average of array covariance matrix (FBACM) to show that its real part (R-FBACM) is a real symmetric matrix. Based on that, we prove that by evaluating two half-dimension EVD after an orthogonally similar transformation performed on the estimated R-FBACM, we are able to reconstruct the original eigenspace whereas the maximum number of estimated sources is reduced as compared to the upper limit M - 1 for original MUSIC. Numerical results show that the proposed method provides satisfactory estimation accuracy and improved resolution with reduced complexity
Anthropology as an interdisciplinary field
No full textThe article discusses anthropology as an interdisciplinary field from the author's own research experience.AnthropologySociologySSCI0ARTICLE120-243
Stratego/XT 0.17. A Language and Toolset for Program Transformation
No full textPreprint of paper published in: Science of Computer Programming (Elsevier), 72 (1-2), 2008; doi:10.1016/j.scico.2007.11.003 Stratego/XT is a language and toolset for program transformation. The Stratego language provides rewrite rules for expressing basic transformations, programmable rewriting strategies for controlling the application of rules, concrete syntax for expressing the patterns of rules in the syntax of the object language, and dynamic rewrite rules for expressing context-sensitive transformations, thus supporting the development of transformation components at a high level of abstraction. The XT toolset offers a collection of flexible, reusable transformation components, and tools for generating such components from declarative specifications. Complete program transformation systems are composed from these components. This paper gives an overview of Stratego/XT 0.17, including a description of the Stratego language and XT transformation tools; a discussion of the implementation techniques and software engineering process; and a description of applications built with Stratego/XT.Software Computer TechnologyElectrical Engineering, Mathematics and Computer Scienc
Simplification of Fan-Meshes models for fast rendering of large 3D point-sampled scenes
No full textFan-Meshes (FM) are a kind of geometrical primitives for generating 3D model or scene descriptions that are able to preserve both local geometrical details and topological structures. In this paper, we propose an efficient simplification algorithm for the FM models to achieve fast post-processing and rendering of large models or scenes. Given a global error tolerance for the surface approximation, the algorithm can find an approximately minimal set of FMs that covers the whole model surfaces. As compared with splat-based methods, the FM description has a large simplification rate under the same surface fitting error measurement.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000232256900012&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Artificial IntelligenceComputer Science, Theory & MethodsImaging Science & Photographic TechnologySCI(E)CPCI-S(ISTP)
Real-Valued MUSIC for Efficient Direction of Arrival Estimation With Arbitrary Arrays: Mirror Suppression and Resolution Improvement
No full textExisting real-valued subspace-based direction of arrival (DOA) estimation methods mainly face two prob-lems: the limitations of uniform linear array (ULA) in practical applications and the presence of virtual mirrored angles. This paper exploits the properties of the virtual signal model of forward/backward av-erage of the array covariance matrix (FBACM), in particular of the eigenvalue-eigenvector decomposition (EVD) of the real part (R-FBACM) and imaginary part (I-FBACM) of the FBACM. Our theoretical analysis proves that the subspace leakage is the cause of virtual mirrored angles. We further prove that FBACM has the same real eigenvalues as the sum of R-FBACM and I-FBACM. Based on this result, we propose a new compound real-valued MUSIC (CRV-MUSIC) algorithm to reconstruct the MUSIC pseudo-spectrum without virtual mirrored angles, which is applicable into arbitrary array configurations. Numerical anal-ysis demonstrate that the proposed CRV-MUSIC algorithm has lower computational complexity, better resolution, and similar estimation accuracy than classical MUSIC and other existing methods.(c) 2022 Elsevier B.V. All rights reserved
XT-ADS sensitivity analysis
No full textThis work has been carried out in the first period (March-June 2010) In which the author Joined the Central Design Team in Mol (B) for the CDT/FASTEF EU FP7 project. Before to start with the deep characterisation foreseen during the WP2 for FASTEF (100 MW LBE cooled reactor, working in both critical and sub-critical modes), a preliminary code tuning has been carried out by adopting the XT-ADS core layout (developed in IP EUROTRANS, EU FP6 project). The tuning deals with the neutronic codes, in particular: ERANOS (deterministic) and MCNPX (Monte Carlo). The main results have been included in the two SCK-CEN calculation notes here reported. The first calculation note (ANS/RMS/TS/ARTD00CDT-02/827/10-15) highlights the main differences between the ERANOS and MCNPX models for XT-ADS. Then the ERANOS input has been modified to consider the same assumptions adopted by MCNPX. A further tuning of both models yields, as a whole, a reduction of the MCNPX-ERANOS keff difference (at BoL) from by about 2700 pcm down to 1000 pcm. The second calculation note (ANS/RMS/TS/ARTD00CDT-02/827/10-16) summarizes the XT-ADS sensitivity analysis performed by ERANOS ver. 2.1 with two different nuclear data Iibraries: JEFF3.1 and ENDF/BVI.8. The study, carried out by exploiting the basics of standard perturbation theory, points out which nuclides, which cross-section and which range of energy yield the most significant impact on the core reactivity. As in the first note, the ERANOS evaluations (performed in a reference and voided configurations) have been compared with the results obtained with the MCNFX code
Oscillation Criteria for First Order Neutral Differential Equations with Positive and Negative Coefficients
No full textSufficient conditions for the oscillation of the equation � xt Ž. � Rt Ž. xt � Ž r.� d
Dui liu tuan liu zhong tiao jian wen du jie gou han shu zhi yan jiu
No full textChau Kwok Leung = 對流湍流中條件溫度結構函數之硏究 / 周國良.Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.Includes bibliographical references (leaves [93]-94).Text in English; abstracts in English and Chinese.Chau Kwok Leung = Dui liu tuan liu zhong tiao jian wen du jie gou han shu zhi yan jiu / Zhou Guoliang.Abstract --- p.iAbstract (Chinese Version) --- p.iiAcknowledgement --- p.iiiTable of contents --- p.ivList of figures --- p.vList of tables --- p.xiiiChapter 1 --- Introduction --- p.1Chapter 2 --- Rayleigh Benard experiments --- p.6Chapter 2.1 --- Rayleigh-Benard Experiment --- p.6Chapter 2.2 --- Rayleigh-Benard Convection using Helium --- p.8Chapter 2.3 --- Rayleigh-Benard Convection Experiment using water --- p.9Chapter 2.4 --- Passive Temperature Measurements in a Wind Tunnel Experiment --- p.10Chapter 3 --- Conditional Probability density function of the Temperature Differences --- p.11Chapter 3.1 --- Approximation of locally averaged temperature dissipation rate --- p.12Chapter 3.2 --- Conditional PDF for r Tb --- p.18Chapter 4 --- Conditional Statistics of Temperature Difference --- p.26Chapter 4.1 --- Distribution of In xT --- p.26Chapter 4.2 --- XT-dependence of 〈\TT\P\XT〉 --- p.28Chapter 4.2.1 --- Xr-dependence for small T --- p.28Chapter 4.2.2 --- XT dependence for large T --- p.31Chapter 4.3 --- "m(T,P)" --- p.39Chapter 4.4 --- Consequence of the Standard Gaussian Conditional PDF for T >Tb --- p.53Chapter 4.5 --- c(T，p) --- p.57Chapter 4.5.1 --- T>Tb --- p.60Chapter 4.5.2 --- T>Tb --- p.64Chapter 5 --- Height dependence of Conditional Temperature Structure Function --- p.69Chapter 5.1 --- Determination of rc and Td --- p.69Chapter 5.2 --- Height dependence of Conditional Temperature Structure Function --- p.72Chapter 6 --- Discussion --- p.78Chapter 6.1 --- Comparison with passive measurement --- p.78Chapter 6.2 --- Pr-dependence of Conditional PDF on XT --- p.87Chapter 7 --- Conclusion --- p.90Bibliography --- p.9
The AgriRover : a reinvented mechatronic platform from space robotics for precision farming
No full textThis paper presents an investigation of a novel development of a multi-functional mobile platform for agriculture applications. This is achieved through a reinven-tion process of a mechatronic design by spinning off space robotic technologies in terrestrial applications in the AgriRover project. The AgriRover prototype is the first of its kind in exploiting and applying space robotic technologies in precision farming. To optimize energy consumption of the mobile platform, a new dynamic total cost of transport algorithm is proposed and validated. An autonomous navi-gation system has been developed to enable the AgriRover to operate safely in unstructured farming environments. An object recognition algorithm specific to agriculture- has been investigated and implemented. A novel soil sample collect-ing mechanism has been designed and prototyped for on-board and in-situ soil quality measurement. The design of the whole system has benefited from the use of a mechatronic design process known as the Tiv model through which a plane-tary exploration rover is reinvented into the AgriRover for agricultural applica-tions. The AgriRover system has gone through three sets of field trials in the UK and some of these results are reported
Spin-polarized current induced by a local exchange field in a silicene nanoribbon
No full textA mechanism to generate a spin-polarized current in a two-terminal zigzag silicene nanoribbon is predicted. When a weak local exchange field that is parallel to the surface of silicene is applied on one of edges of the silicene nanoribbon, a gap is opened in the corresponding edge states but another pair of gapless edge states with opposite spin are still protected by the time-reversal symmetry. Hence, a spin-polarized current can be induced in the gap opened by the local exchange field in this two-terminal system. What is important is that the spin-polarized current can be obtained even in the absence of Rashba spin-orbit coupling and in the case of the very weak exchange field. That is to say, the mechanism to generate the spin-polarized currents can be easily realized experimentally. We also find that the spin-polarized current is insensitive to weak disorder.Physics, MultidisciplinarySCI(E)EI13ARTICLEnull1
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