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Assessment of algorithms for the no-slip boundary condition in the lattice Boltzmann equation of BGK model

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS 2008年第12期58卷 1353-1378页

作者： Suh, Yong Kweon Kang, Jinfen Kang, Sangmo Dong A Univ Dept Mech Engn Pusan 604714 South Korea

Three kinds of algorithms for the lattice Boltzmann equation of the BGK model in the implementation of the no-slip boundary condition on the wall are assessed by using the analytical formula for the slip velocity of the fully developed pressure-driven channel How. It is shown that the bounce-back algorithm results in the spatial accuracy of 1st order, except for the case when the wall is located at half way between the two grid lines. The interpolation scheme proposed by Yu et at. (Prog. Aerospace Sci. 2003;39:329-367) and the similar one by Bouzidi et al. (Phys. Fluids 2001 13(11):3452-3459) are of 2nd order, but the error increases quadratically with the relaxation time. The extrapolation scheme of Guo et al. (Phys. Fluids 2002;14(6):2007-2010) is also shown to be of 2nd order, and the error level increases linearly with the relaxation time, but it turns Out that this scheme is unstable for a certain range of parameter values. Numerical experiments with various parameter sets have been performed to obtain the stability diagram. Three algorithms are then applied to a circular-Couette flow and their performance is also studied in terms of the numerical accuracy and stability. Copyright (C) 2008 John Wiley & Sons, Ltd.

关键词： lattice Boltzmann equation BGK model no-slip boundary condition interpolation algorithm extrapolation algorithm channel flow circular-Couette flow

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Developing continuous machining strategy for cost-effective five-axis CNC milling systems with a four-axis controller

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INTERNATIONAL JOURNAL OF COMPUTER INTEGRATED MANUFACTURING 2020年第5期33卷 474-490页

作者： Liu, Jiang Huang, Leiyang Wang, Yesong Wang, Yachao Shi, Jing Univ Sci & Technol Beijing Sch Mech Engn Beijing Peoples R China Univ Cincinnati Dept Mech & Mat Engn Cincinnati OH 45221 USA

This paper investigates the five-axis continuous machining strategy on cost-effective five-axis CNC milling systems, which is limited by simultaneous control of any four axes at a given time. The proposed strategy consists of (1) generation of five-axis continuous milling tool path for conventional five-axis machines using a CAD/CAM software, and (2) conversion of the generated tool path to four-axis tool trajectory based on a novel interpolation algorithm. The interpolation algorithm is built on the relationship between the position data of the tool and the displacement of the machine tool axis. The position of the interpolation point is determined by the offset distance of the interpolation point, and the error of the interpolation is controlled by the dichotomy method. Furthermore, two simulation case studies are conducted to verify the effectiveness of the proposed algorithm. One case study is on a standard 'S' test piece, and the other study is on a more complicated geometry - an impeller part. The generated five-axis continuous paths are converted to the four-axis trajectory by the proposed algorithm. Machining simulations are performed using both the five-axis continuous path and the converted four-axis continuous path. The conversion quality is found to be satisfactory for both cases.

关键词： Five-axis CNC machine continuous machining tool path interpolation algorithm conversion error

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Mapping Atmospheric Corrosivity in Shandong

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WATER AIR AND SOIL POLLUTION 2020年第12期231卷 1-13页

作者： Fan, Zhibin Li, Xingeng Jiang, Bo Wang, Xiaoming Wang, Qian State Grid Shandong Elect Power Res Inst State Grid Corp Joint Lab Adv Elect Engn Mat SDEP Jinan 250001 Peoples R China

Air pollution can significantly accelerate the process of material corrosion, which may cause significant economic losses and serious safety incidents. Atmospheric corrosion maps provide atmospheric corrosivity in a given geographic scope, which can guide the designers to select the most suitable anti-corrosion materials for outdoor projects, also provide useful information for maintenance. This article investigated mapping of atmospheric corrosivity in Shandong Province, China. In order to obtain atmospheric corrosivity data, 100 exposure corrosion test sites were established in Shandong according to International Standard Organization (ISO) 8565. Hot-dip galvanized steel samples were exposed for 1 year in the test sites. Taking the results of exposure corrosion test as the data, inverse distance weighting (IDW) and ordinary kriging (OK) interpolation algorithm were used to estimate the atmospheric corrosivity of Shandong Province according to ISO 9223. The validity of OK and IDW was compared in developing atmospheric corrosion maps of Shandong Province on a 1x1 km resolution. The cross-validation results showed that OK interpolation algorithm with Gaussian semivariogram model get the best result in the prediction of corrosion rate. When the corrosion category was used as the criterion, the IDW interpolation algorithm of power 4 performed best, predicted results of 74 sites (n=100) were consistent with observed. However, high mean relative errors (MRE more than 37%) and relatively low correlation (R-2 about 24%) indicated that the prediction results of the two interpolation algorithms had a large error, which was caused by the low data density and the complicated corrosive factors of the atmosphere.

关键词： Atmospheric corrosion maps interpolation algorithm Ordinary kriging Inverse distance weighting Cross-validation

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Rapid accurate frequency estimation of multiple resolved exponentials in noise

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SIGNAL PROCESSING 2017年 132卷 29-39页

作者： Ye, Shanglin Aboutanios, Elias Univ New South Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia

The estimation of the frequencies of the sum of multiple resolved exponentials in noise is an important problem due to its application in diverse areas from engineering to chemistry. Yet to date, no low cost Fourier-based algorithm has been successful at obtaining unbiased estimates that achieve the Cramer Rao lower bound (CRLB) over a wide range of signal-to-noise ratios. In this work, we achieve precisely this goal, proposing a fast yet accurate estimator that combines an iterative frequency-domain interpolation step with a leakage subtraction scheme. By analysing the asymptotic performance and the convergence behaviour of the estimator, we show that the estimate of each frequency converges to the asymptotic fixed point. Thus, the estimator is asymptotically unbiased and the variance is extremely close to the CRLB. We verify the theoretical analysis by extensive simulations, and demonstrate that the proposed algorithm is capable of obtaining more accurate estimates than state-of-the-art high resolution methods while requiring significantly less computational effort. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Frequency estimation Resolved exponentials interpolation algorithm Fourier coefficient Leakage subtraction

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Learning to rank with relational graph and pointwise constraint for cross-modal retrieval

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SOFT COMPUTING 2019年第19期23卷 9413-9427页

作者： Xu, Qingzhen Li, Miao Yu, Mengjing South China Normal Univ Sch Comp Guangzhou 510631 Guangdong Peoples R China

Cross-modal retrieval (i.e., image-query-text or text-query-image) is a hot research topic for multimedia information retrieval, but the heterogeneity gap between different modalities generates a critical challenge for multimodal data. Some researchers regard the cross-modal retrieval as a leaning to rank task, and they usually consider to measure similarity between two different modalities in the embedding shared subspace. However, previous methods almost pay more attention to construct a discriminative objective function to optimize common space, ignoring to exploit correlation between the single modality. In this paper, we consider the cross-modal retrieval task, from the perspective of optimizing ranking model, as a listwise ranking problem, and propose a novel method called learning to rank with relational graph and pointwise constraint (LR(2)GP). In LR(2)GP, we first propose a discriminative ranking model, which makes use of the relation between the single modality to improve ranking performance so as to learn an optimal embedding common subspace. Then, a pointwise constraint is introduced in the low-dimension embedding subspace to make up for the real loss in the training phase since listwise method introduced merely considers directly optimize latent permutation from the perspective of the overall. Finally, a dynamic interpolation algorithm, which gradually transits from pointwise and pairwise to listwise learning, is selected to deal with the problem of fusion of loss function reasonable. Experiments on the benchmark datasets about Wikipedia and Pascal demonstrate the effectiveness for proposed method.

关键词： Cross-modal retrieval Ranking model Single modality Pointwise constraint interpolation algorithm

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A Novel Toolpath for Robotic Adaptive Grinding of Extremely Thin Blade Edge Based on Dwell Time Model

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IEEE-ASME TRANSACTIONS ON MECHATRONICS 2022年第6期27卷 4429-4439页

作者： Lv, Chong Zou, Lai Huang, Yun Li, Heng Wang, Tingting Mu, Yilin Chongqing Univ Coll Mech & Vehicle Engn State Key Lab Mech Transmiss Chongqing 400044 Peoples R China

High precision and high efficiency in robotic grinding of aero-engine extremely thin blade edges is a challenging problem. In this article, a novel toolpath planning method is proposed based on the derived dwell time calculation model and the developed interpolation algorithm. The dwell time of each cutter contact point is solved based on the matrix method by consideration of the revised material removal model and machining allowance distribution. To optimize the previous interpolation algorithm based on geometric intersection, an arc length and Taylor binary expansion optimization are proposed to plan cutter contact points according to the dwell time and the curvature changes of blade edges. Subsequently, the tool orientation is corrected based on a double-vector controlling method to avoid the processing interference. Simulation results show that the proposed interpolation algorithm has improved the path coverage by 17.6%, and its computational efficiency is 34 times higher than that in previous algorithm. The comparative robotic grinding experiment results show that the proposed toolpath has improved the surface profile accuracy of blade edge to 0.042 mm, and its machining accuracy is 14.3-46.2% higher than that of other methods.

关键词： Aero-engine blade dwell time interpolation algorithm robotic grinding toolpath planning uneven allowance

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Design and evaluation of a novel formulation prediction system

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INTERNATIONAL JOURNAL OF PHARMACEUTICS 2010年第1-2期402卷 129-139页

作者： Guan, Jin Xiang, Rongwu Pan, Yusheng Pan, Hao Su, Xiangdong Zhou, Liying Cui, Yuni Pan, Weisan Shenyang Pharmaceut Univ Dept Pharmaceut Sch Pharm Shenyang 110016 Peoples R China Shenyang Pharmaceut Univ Math Teaching & Res Sect Shenyang 110016 Peoples R China Shenyang Ligong Univ Res & Dev Ctr CAD CAM Shenyang 110168 Peoples R China

Purpose: The purpose of this study is to design and evaluate a novel formulation prediction system for formulation study of monolithic osmotic pump tablets (MOPTs). Methods: Ternary-component diagram was originally brought forward to evaluate MOPTs formulations. Optimal formulation regions were delimited in ternary-component diagrams. Water-insoluble drug gliclazide was chosen as a model drug for selecting most suitable suspending agent. With five model drugs, we obtained five ternary-component diagrams. By MATLAB (R) software, a triangular prism model was then established regarding doses as vertical coordinate and the five diagrams as cross-sections, with the formation of an optimal formulation channel in it, followed by the design of formulation prediction software (FPS 1.0). The practicality of the system was finally validated. Results: After entering the drug information, we immediately obtained the optimal formulation region for preparing MOPTs with interpolation algorithm. The dissolution test results of the four randomly selected formulations all met the evaluating conditions. Conclusions: Ternary-component diagram is useful for MOPTs formulation optimization. The predictive ability of the system is tentatively confirmed and the experiment efficiency is greatly improved. (c) 2010 Elsevier B.V. All rights reserved.

关键词： Formulation prediction system Ternary-component diagram Optimal formulation region Triangular prism model interpolation algorithm Monolithic osmotic pump tablets

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RSS-Based DoA Estimation Using ESPAR Antennas and Interpolated Radiation Patterns

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2018年第1期17卷 25-28页

作者： Kulas, Lukasz Gdansk Univ Technol Fac Elect Telecommun & Informat Dept Microwave & Antenna Engn PL-80233 Gdansk Poland

In this letter, it is shown how an algorithm, which employs received signal strength values in order to estimate direction of arrival (DoA) of impinging signals in wireless sensor network (WSN) nodes equipped with electronically steerable parasitic array radiator (ESPAR) antennas, can easily be improved by applying an interpolation algorithm to radiation patterns recorded in the calibration phase of the DoA estimation process. The proposed method allows one to measure ESPAR antenna's radiation patterns during the initial calibration phase with much coarser than 1 degrees angular resolution, while the overall DoA estimation accuracy can be kept at the similar level. Measurements using a fabricated ESPAR antenna have indicated that anechoic chamber calibration procedure of WSN nodes equipped with such antennas can be done almost 50% faster, which in consequence will reduce system deployment costs in practical WSN applications where a number of WSN nodes can easily reach hundreds.

关键词： direction of arrival (DoA) electronically steerable parasitic array radiator (ESPAR) antenna interpolation algorithm received signal strength (RSS) switched-beam antenna

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A Bio-inspired trajectory planning method for robotic manipulators based on improved bacteria foraging optimization algorithm and tau theory

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MATHEMATICAL BIOSCIENCES AND ENGINEERING 2022年第1期19卷 643-662页

作者： Wang, Zhiqiang Peng, Jinzhu Ding, Shuai Zhengzhou Univ Sch Elect Engn 100 Sci Ave Zhengzhou 450001 Peoples R China

In this paper, a novel bio-inspired trajectory planning method is proposed for robotic sys-tems based on an improved bacteria foraging optimization algorithm (IBFOA) and an improved in-trinsic Tau jerk (named Tau-J*) guidance strategy. Besides, the adaptive factor and elite-preservation strategy are employed to facilitate the IBFOA, and an improved Tau-J* with higher-order of intrinsic guidance movement is used to avoid the nonzero initial and final jerk, so as to overcome the computa-tional burden and unsmooth trajectory problems existing in the optimization algorithm and traditional interpolation algorithm. The IBFOA is utilized to determine a small set of optimal control points, and Tau-J* is then invoked to generate smooth trajectories between the control points. Finally, the results of simulation tests demonstrate the eminent stability, optimality, and rapidity capability of the proposed bio-inspired trajectory planning method.

关键词： robotic manipulator trajectory planning improved bacteria foraging optimization algorithm Tau theory interpolation algorithm multi-objective optimization

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Thermal protection system gap analysis using a loosely coupled fluid-structural thermal numerical method

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ACTA ASTRONAUTICA 2018年 146卷 368-377页

作者： Huang, Jie Li, Piao Yao, Weixing Nanjing Univ Aeronaut & Astronaut Nanjing 210016 Jiangsu Peoples R China

A loosely coupled fluid-structural thermal numerical method is introduced for the thermal protection system (TPS) gap thermal control analysis in this paper. The aerodynamic heating and structural thermal are analyzed by computational fluid dynamics (CFD) and numerical heat transfer (NHT) methods respectively. An interpolation algorithm based on the control surface is adopted for the data exchanges on the coupled surface. In order to verify the analysis precision of the loosely coupled method, a circular tube example was analyzed, and the wall temperature agrees well with the test result. TPS gap thermal control performance was studied by the loosely coupled method successfully. The gap heat flux is mainly distributed in the small region at the top of the gap which is the high temperature region. Besides, TPS gap temperature and the power of the active cooling system (CCS) calculated by the traditional uncoupled method are higher than that calculated by the coupled method obviously. The reason is that the uncoupled method doesn't consider the coupled effect between the aerodynamic heating and structural thermal, however the coupled method considers it, so TPS gap thermal control performance can be analyzed more accurately by the coupled method.

关键词： Thermal protection system Gap thermal control analysis Loosely coupled method interpolation algorithm

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