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Boundary Value Methods for Second-Order PDEs via the Lanczos-Chebyshev Reduction Technique

MATHEMATICAL PROBLEMS IN ENGINEERING 2017年第1期2017卷 1-11页

作者： Biala, T. A. Jator, S. N. Adeniyi, R. B. Sule Lamido Univ Dept Math & Comp Sci PMB 048 Kafin Hausa Nigeria Austin Peay State Univ Dept Math & Stat Clarksville TN 37044 USA Univ Ilorin Dept Math Ilorin Nigeria

In this paper, we study the performance of Boundary Value Methods (BVMs) on second-order PDEs. The PDEs are transformed into a system of second-order ordinary differential equations (ODEs) using the Lanczos-Chebyshev reduction technique. The conditions under which the BVMs converge and the computational complexities of the algorithms are discussed. Numerical illustrations are given to show the simplicity and high accuracy of the approach.

关键词： BOUNDARY value problems LANCZOS method ORDINARY differential equations COMPUTATIONAL complexity computer algorithms

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Map Matching Based on Conditional Random Fields and Route Preference Mining for Uncertain Trajectories

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MATHEMATICAL PROBLEMS IN ENGINEERING 2015年第1期2015卷 1-13页

作者： Xu, Ming Du, Yiman Wu, Jianping Zhou, Yang Beijing Univ Posts & Telecommun Sch Comp Sci Beijing 100876 Peoples R China Tsinghua Univ Sch Civil Engn Beijing 100084 Peoples R China

In order to improve offline map matching accuracy of uncertain GPS trajectories, a map matching algorithm based on conditional random fields (CRF) and route preference mining is proposed. In this algorithm, road offset distance and the temporal-spatial relationship between the sampling points are used as features of GPS trajectory in a CRF model, which integrates the temporal-spatial context information flexibly. The driver route preference is also used to bolster the temporal-spatial context when a low GPS sampling rate impairs the resolving power of temporal-spatial context in CRF, allowing the map matching accuracy of uncertain GPS trajectories to get improved significantly. The experimental results show that our proposed algorithm is more accurate than existing methods, especially in the case of a low-sampling-rate.

关键词： MAPS RANDOM fields TRAJECTORIES (Mechanics) GLOBAL Positioning System computer algorithms

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ISP-Friendly Data Scheduling by Advanced Locality-Aware Network Coding for P2P Distribution Cloud

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-11页

作者： Li, Yanjun Zhang, Guoqing Zhang, Guoqiang Chinese Acad Sci Inst Comp Technol Beijing 100190 Peoples R China Nanjing Normal Univ Sch Comp Sci & Technol Nanjing 210023 Jiangsu Peoples R China

Peer-to-peer (P2P) file distribution imposes increasingly heavy traffic burden on the Internet service providers (ISPs). The vast volume of traffic pushes up ISPs' costs in routing and investment and degrades their networks performance. Building ISP-friendly P2P is therefore of critical importance for ISPs and P2P services. So far most efforts in this area focused on improving the locality-awareness of P2P applications, for example, to construct overlay networks with better knowledge of the underlying network topology. There is, however, growing recognition that data scheduling algorithms also play an effective role in P2P traffic reduction. In this paper, we introduce the advanced locality-aware network coding (ALANC) for P2P file distribution. This data scheduling algorithm completely avoids the transmission of linearly dependent data blocks, which is a notable problem of previous network coding algorithms. Our simulation results show that, in comparison to other algorithms, ALANC not only significantly reduces interdomain P2P traffic, but also remarkably improves both the application-level performance (for P2P services) and the network-level performance (for ISP networks). For example, ALANC is 30% faster in distributing data blocks and it reduces the average traffic load on the underlying links by 40%. We show that ALANC holds the above gains when the tit-for-tat incentive mechanism is introduced or the overlay topology changes dynamically.

关键词： PEER-to-peer architecture (computer networks) INTERNET service providers computer scheduling CODING theory computer algorithms

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Mixed Kinematic and Dynamic Sideslip Angle Observer for Accurate Control of Fast Off-Road Mobile Robots

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JOURNAL OF FIELD ROBOTICS 2010年第2期27卷 181-196页

作者： Lenain, Roland Thuilot, Benoit Cariou, Christophe Martinet, Philippe Irstea F-63172 Aubiere France Lasmea F-63177 Clermont Ferrand France

Automation ill Outdoor applications (farming, Surveillance, military activities, etc.) requires highly accurate control of mobile robots, at high speed, although they are moving on low-grip terrain. To meet such expectations, advanced control laws accounting for natural ground specificities (mainly sliding effects) must be derived. In previous work, adaptive and predictive control algorithms, based on an extended kinematic representation, have been proposed. Satisfactory experimental results have been reported (accurate to within +/- 10 cm,, whatever the grip conditions), but at limited velocity (below 3 m.s(-1)). Nevertheless, simulations reveal that control accuracy is decreased when vehicle speed is increased (up to 10 m.S-1). In particular, oscillations are observed at curvature transition. This drawback is due to delays in sideslip angle estimation, unavoidable at high speed because only an extended kinematic representation was used. hi this paper, a mixed backstepping kinematic and dynamic observer is designed to improve observation of these variables: the slow-varying data are still estimated from a kinematic representation, which is then injected into a dynamic observer to supply reactive and reliable sliding variable (namely sideslip angle) estimation, without increasing the noise level. The algorithm is evaluated via advanced Simulations (coupling Adams and MatLab software) investigating highspeed capabilities. Actual experiments at lower speed (experimental platform maximum velocity) demonstrate the benefits of the proposed approach. (C) 2009 Wiley Periodicals, Inc.

关键词： MATLAB accuracy control SIDESLIP Angle control accuracy Fasting Noise levels High speed Vehicle speed kinematics Mobile robots computer algorithms

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Numerically controlled oscillators with hybrid function generators

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IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL 2002年第7期49卷 995-1004页

作者： Janiszewski, I Hoppe, B Meuth, H Univ Appl Sci D-64295 Darmstadt Germany

Numerically controlled oscillators (NCOs), with a hybrid scheme of both look-up tables (LUT) and coordinate transformation digital computer (CORDIC) algorithms for a hardware efficient, high performance sine/cosine function generation are investigated. This scheme combines fast access and power efficiency of reasonably sized LUTs, and arbitrary precision obtainable from a rigorous iteration algorithm. Systematic studies using hardware description language (HDL) models and synthesis lead to optimum LUT/CORDIC ratios, which minimize power consumption and silicon area for a given operating clock frequency. First order error models are presented as guidelines for choosing internal NCO parameters. The NCO accuracy is tested with HDL simulations for all algorithmic states to limit output errors to 1 least significant bit (LSB) and by spectra derived from discrete Fourier transform (DFT) for typical frequency inputs f, resulting in a signal to noise ratio (SNR) of better than 100 dB for an amplitude word length AW of 16 Bit. Two benchmark designs were adopted for the two clock frequencies 200 MHz and 20 MHz, as "high" and "moderate" performance, respectively. The NCO models are synthesized in a 0.35 mum CMOS standard cell target technology and optimized to actually achieve after layout maximum clock frequencies exceeding 310 MHz, i.e., signal frequencies of up to 100 MHz.

关键词： FREQUENCY synthesizers computer algorithms CRYSTAL oscillators

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Control of Structural Response Under Earthquake Excitation

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computer-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING 2012年第8期27卷 620-638页

作者： Aldemir, Unal Yanik, Arcan Bakioglu, Mehmet Istanbul Tech Univ Div Mech Fac Civil Engn TR-34469 Istanbul Turkey

This study firstly proposes some representative simple methods to obtain the suboptimal passive damping and stiffness parameters from the optimal control gain matrix since it is not possible to add the exact optimal damping and stiffness parameters to the structure in practice. It is shown numerically that modifying the structural damping and the stiffness in the proposed suboptimal ways may suppress the uncontrolled vibrations while the performance levels depend on the seismic inputs. Since the proposed approach is intrinsically passive and has no adaptive property against changing dynamic effects, this study secondly proposes a new performance index so that the mechanical energy of the structure, control and the seismic energies are considered simultaneously in the minimization procedure. The implementation of the resulting closed-loop control algorithm does not require both a priori knowledge of the seismic excitation and the solution of the nonlinear matrix Riccati equation. The performance of the proposed approach is investigated, e.g., structures subjected to three seismic inputs and compared to the performance of the uncontrolled, the classical linear optimal control, and the passive cases. It is shown by the numerical simulation results that the proposed algorithm is capable of suppressing the uncontrolled seismic structural displacements and the absolute accelerations simultaneously and performs almost as well as the classical linear optimal control in reducing the displacements with comparable control effort and performs better than the classical linear optimal control in reducing the absolute accelerations. The results show that while the proposed active approach has similar performance to the classical linear optimal control, the classical linear optimal control increases the absolute accelerations slightly compared to the proposed active approach in regulating displacements, while the proposed active approach regulates and reduces both displacements and

关键词： Linear optimal control displacements non-structural component Riccati equations structure control MECHANICAL ENERGY Earthquakes acceleration performance indicators computer algorithms STRUCTURAL RESPONSE Level of Performance

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Analysis of power control for indoor optical wireless code-division multiple access networks using on-off keying and binary pulse position modulation

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IET COMMUNICATIONS 2010年第16期4卷 1919-1933页

作者： Khazraei, S. Pakravan, M. R. Aminzadeh-Gohari, A. Sharif Univ Technol Dept Elect Engn Adv Commun Res Inst Opt Commun & Data Networks Res Lab Tehran 113659363 Iran

Wireless infrared optical code-division multiple access (W-OCDMA) is a new developing technique with many useful applications. Noting the limitation on power consumption and eye-safety requirements, wireless optical systems are power limited. Therefore control and efficient use of optical power is a key issue in analysis and design of these systems. Also, multi-user interference is the major source of impairment in these systems and power control is required to control and reduce this interference. Power control and the inevitable errors in its algorithms play an important role in design and implementation of these systems. In this article the authors study the uplink performance of W-OCDMA networks employing on-off keying (OOK) and binary pulse position modulation (BPPM) schemes without any power control algorithm. The performance improvement as a result of using perfect power control is calculated. Then, the impact of imperfect power control that is the result of channel estimation error is analysed. The results clearly illustrate that deploying a proper and accurate power control algorithm can increase network capacity and reduce network average power consumption. The authors show that systems with non-ideal power control still perform considerably better than no-power controlled systems.

关键词： Pulse position modulation Power control Code division multiple access position modulation keying access network on-off keying binary pulse computer algorithms

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Parts-based face super-resolution via non-negative matrix factorization

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computerS & ELECTRICAL ENGINEERING 2014年第8期40卷 130-141页

作者： Wang, Xiaofeng Ling, Hefei Xu, Xin Huazhong Univ Sci & Technol Sch Comp Sci & Technol Wuhan 430074 Peoples R China Wuhan Univ Sci & Technol Sch Comp Sci & Technol Wuhan 430081 Peoples R China

Face super-resolution refers to inferring the high-resolution face image from its low-resolution one. In this paper, we propose a parts-based face hallucination framework which consists of global face reconstruction and residue compensation. In the first phase, correlation-constrained non-negative matrix factorization (CCNMF) algorithm combines non-negative matrix factorization and canonical correlation analysis to hallucinate the global high-resolution face. In the second phase, the High-dimensional Coupled NMF (HCNMF) algorithm is used to compensate the error residue in hallucinated images. The proposed CCNMF algorithm can generate global face more similar to the ground truth face by learning a parts-based local representation of facial images;while the HCNMF can learn the relation between high-resolution residue and low-resolution residue to better preserve high frequency details. The experimental results validate the effectiveness of our method. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： HIGH resolution imaging FACTORIZATION (Mathematics) IMAGE processing computer algorithms HUMAN face recognition (computer science)

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Short-Term Wind Speed Forecasting Using the Data Processing Approach and the Support Vector Machine Model Optimized by the Improved Cuckoo Search Parameter Estimation Algorithm

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MATHEMATICAL PROBLEMS IN ENGINEERING 2016年第1期2016卷 1-17页

作者： Wang, Chen Wu, Jie Wang, Jianzhou Hu, Zhongjin Lanzhou Univ Sch Math & Stat Lanzhou 730000 Peoples R China Northwest Univ Nationalities Sch Math & Comp Sci Lanzhou 730030 Peoples R China Dongbei Univ Finance & Econ Sch Stat Dalian 116025 Peoples R China

Power systems could be at risk when the power-grid collapse accident occurs. As a clean and renewable resource, wind energy plays an increasingly vital role in reducing air pollution and wind power generation becomes an important way to produce electrical power. Therefore, accurate wind power and wind speed forecasting are in need. In this research, a novel short-term wind speed forecasting portfolio has been proposed using the following three procedures: ( I) data preprocessing: apart from the regular normalization preprocessing, the data are preprocessed through empirical model decomposition ( EMD), which reduces the effect of noise on the wind speed data;( II) artificially intelligent parameter optimization introduction: the unknown parameters in the support vector machine ( SVM) model are optimized by the cuckoo search ( CS) algorithm;( III) parameter optimization approach modification: an improved parameter optimization approach, called the SDCS model, based on the CS algorithm and the steepest descent ( SD) method is proposed. The comparison results show that the simple and effective portfolio EMD-SDCS-SVM produces promising predictions and has better performance than the individual forecasting components, with very small rootmean squared errors and mean absolute percentage errors.

关键词： WIND speed measurements ELECTRONIC data processing SUPPORT vector machines computer algorithms HILBERT-Huang transform

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Decentralized Identification and Control in Real-Time of a Robot Manipulator via Recurrent Wavelet First-Order Neural Network

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MATHEMATICAL PROBLEMS IN ENGINEERING 2015年第1期2015卷 1-12页

作者： Vazquez, Luis A. Jurado, Francisco Alanis, Alma Y. Inst Tecnol La Laguna Tecnol Nacl Mexico Torreon 27000 Coah Mexico Univ Guadalajara CUCEI Guadalajara 44430 Jal Mexico

A decentralized recurrent wavelet first-order neural network (RWFONN) structure is presented. The use of a wavelet Morlet activation function allows proposing a neural structure in continuous time of a single layer and a single neuron in order to identify online in a series-parallel configuration, using the filtered error (FE) training algorithm, the dynamics behavior of each joint for a two-degree-of-freedom (DOF) vertical robot manipulator, whose parameters such as friction and inertia are unknown. Based on the RWFONN subsystem, a decentralized neural controller is designed via backstepping approach. The performance of the decentralized wavelet neural controller is validated via real-time results.

关键词： DECENTRALIZATION in management ROBOTS WAVELETS (Mathematics) computer algorithms DEGREES of freedom

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