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landscape classification using Chinese advanced high-resolution satellite imagery and an object-oriented multi-variablemodel

Li-gang MA,Jin-song DENG,Huai YANG,Yang HONG,Ke WANG

《信息与电子工程前沿（英文）》 2015年 第16卷 第3期   页码 238-248 doi: 10.1631/FITEE.1400083

摘要： The Chinese ZY-1 02C satellite is one of the most advanced high-resolution earth observation systems designed for terrestrial resource monitoring. Its capability for comprehensive landscape classification, especially in urban areas, has been under constant study. In view of the limited spectral resolution of the ZY-1 02C satellite (three bands), and the complexity and heterogeneity across urban environments, we attempt to test its performance of urban landscape classification by combining a multivariable model with an object-oriented approach. The multiple variables including spectral reflection, texture, spatial autocorrelation, impervious surface fraction, vegetation, and geometry indexes were first calculated and selected using forward stepwise linear discriminant analysis and applied in the following object-oriented classification process. Comprehensive accuracy assessment which adopts traditional error matrices with stratified random samples and polygon area consistency (PAC) indexes was then conducted to examine the real area agreement between a classified polygon and its references. Results indicated an overall classification accuracy of 92.63% and a kappa statistic of 0.9124. Furthermore, the proposed PAC index showed that more than 82% of all polygons were correctly classified. Misclassification occurred mostly between residential area and barren/farmland. The presented method and the Chinese ZY-1 02C satellite imagery are robust and effective for urban landscape classification.

关键词： ZY-1 02C satellite     Classification     Urban     Multi-variable model    

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Mechanical responses of multi-layered ground due to shallow tunneling with arbitrary ground surface load

《结构与土木工程前沿（英文）》 2023年 第17卷 第5期   页码 745-762 doi: 10.1007/s11709-023-0935-4

摘要： An analytical model based on complex variable theory is proposed to investigate ground responses due to shallow tunneling in multi-layered ground with an arbitrary ground surface load. The ground layers are assumed to be linear-elastic with full-stick contact between them. To solve the proposed multi-boundary problem, a series of analytic functions is introduced to accurately express the stresses and displacements contributed by different boundaries. Based on the principle of linear-elastic superposition, the multi-boundary problem is converted into a superposition of multiple single-boundary problems. The conformal mappings of different boundaries are independent of each other, which allows the stress and displacement fields to be obtained by the sum of components from each boundary. The analytical results are validated based on numerical and in situ monitoring results. The present model is superior to the classical model for analyzing ground responses of shallow tunneling in multi-layered ground; thus, it can be used with assurance to estimate the ground movement and surface building safety of shallow tunnel constructions beneath surface buildings. Moreover, the solution for the ground stress distribution can be used to estimate the safety of a single-layer composite ground.

关键词： analytical model     mechanical response     multi-layered ground     shallow tunneling     ground surface load     complex variable solution    

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Performance design of a cryogenic air separation unit for variable working conditions using the lumpedparameter model

Jinghua XU, Tiantian WANG, Qianyong CHEN, Shuyou ZHANG, Jianrong TAN

《机械工程前沿（英文）》 2020年 第15卷 第1期   页码 24-42 doi: 10.1007/s11465-019-0558-6

摘要： Large-scale cryogenic air separation units (ASUs), which are widely used in global petrochemical and semiconductor industries, are being developed with high operating elasticity under variable working conditions. Different from discrete processes in traditional machinery manufacturing, the ASU process is continuous and involves the compression, adsorption, cooling, condensation, liquefaction, evaporation, and distillation of multiple streams. This feature indicates that thousands of technical parameters in adsorption, heat transfer, and distillation processes are correlated and merged into a large-scale complex system. A lumped parameter model (LPM) of ASU is proposed by lumping the main factors together and simplifying the secondary ones to achieve accurate and fast performance design. On the basis of material and energy conservation laws, the piecewise-lumped parameters are extracted under variable working conditions by using LPM. Takagi–Sugeno (T–S) fuzzy interval detection is recursively utilized to determine whether the critical point is detected or not by using different thresholds. Compared with the traditional method, LPM is particularly suitable for “rough first then precise” modeling by expanding the feasible domain using fuzzy intervals. With LPM, the performance of the air compressor, molecular sieve adsorber, turbo expander, main plate-fin heat exchangers, and packing column of a 100000 Nm O /h large-scale ASU is enhanced to adapt to variable working conditions. The designed value of net power consumption per unit of oxygen production (kW/(Nm O )) is reduced by 6.45%.

关键词： performance design     air separation unit (ASU)     lumped parameter model (LPM)     variable working conditions     T–S fuzzy interval detection    

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Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault

Hamed HABIBI, Hamed RAHIMI NOHOOJI, Ian HOWARD

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 377-388 doi: 10.1007/s11465-017-0431-4

摘要：

Power maximization has always been a practical consideration in wind turbines. The question of how to address optimal power capture, especially when the system dynamics are nonlinear and the actuators are subject to unknown faults, is significant. This paper studies the control methodology for variable-speed variable-pitch wind turbines including the effects of uncertain nonlinear dynamics, system fault uncertainties, and unknown external disturbances. The nonlinear model of the wind turbine is presented, and the problem of maximizing extracted energy is formulated by designing the optimal desired states. With the known system, a model-based nonlinear controller is designed; then, to handle uncertainties, the unknown nonlinearities of the wind turbine are estimated by utilizing radial basis function neural networks. The adaptive neural fault tolerant control is designed passively to be robust on model uncertainties, disturbances including wind speed and model noises, and completely unknown actuator faults including generator torque and pitch actuator torque. The Lyapunov direct method is employed to prove that the closed-loop system is uniformly bounded. Simulation studies are performed to verify the effectiveness of the proposed method.

关键词： wind turbine nonlinear model     maximum power tracking     passive fault tolerant control     adaptive neural control    

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Development of machine learning multi-city model for municipal solid waste generation prediction

《环境科学与工程前沿（英文）》 2022年 第16卷 第9期 doi: 10.1007/s11783-022-1551-6

摘要：

● A database of municipal solid waste (MSW) generation in China was established.

关键词： Municipal solid waste     Machine learning     Multi-cities     Gradient boost regression tree    

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Simulation of cohesive crack growth by a variable-node XFEM

Weihua FANG, Jiangfei WU, Tiantang YU, Thanh-Tung NGUYEN, Tinh Quoc BUI

《结构与土木工程前沿（英文）》 2020年 第14卷 第1期   页码 215-228 doi: 10.1007/s11709-019-0595-6

摘要： A new computational approach that combines the extended finite element method associated with variable-node elements and cohesive zone model is developed. By using a new enriched technique based on sign function, the proposed model using 4-node quadrilateral elements can eliminate the blending element problem. It also allows modeling the equal stresses at both sides of the crack in the crack-tip as assumed in the cohesive model, and is able to simulate the arbitrary crack-tip location. The multiscale mesh technique associated with variable-node elements and the arc-length method further improve the efficiency of the developed approach. The performance and accuracy of the present approach are illustrated through numerical experiments considering both mode-I and mixed-mode fracture in concrete.

关键词： extended finite element method     cohesive zone model     sign function     crack propagation    

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Amodified variable rate particle filter for maneuvering target tracking

Yun-fei GUO,Kong-shuai FAN,Dong-liang PENG,Ji-an LUO,Han SHENTU

《信息与电子工程前沿（英文）》 2015年 第16卷 第11期   页码 985-994 doi: 10.1631/FITEE.1500149

摘要： To address the problem of maneuvering target tracking, where the target trajectory has prolonged smooth regions and abrupt maneuvering regions, a modified variable rate particle filter (MVRPF) is proposed. First, a Cartesian-coordinate based variable rate model is presented. Compared with conventional variable rate models, the proposed model does not need any prior knowledge of target mass or external forces. Consequently, it is more convenient in practical tracking applications. Second, a maneuvering detection strategy is adopted to adaptively adjust the parameters in MVRPF, which helps allocate more state points at high maneuver regions and fewer at smooth regions. Third, in the presence of small measurement errors, the unscented particle filter, which is embedded in MVRPF, can move more particles into regions of high likelihood and hence can improve the tracking performance. Simulation results illustrate the effectiveness of the proposed method.

关键词： Maneuvering target tracking     Prolonged smooth regions     Variable rate model     Maneuver detection    

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A practical multi-lane factor model of bridges based on multi-truck presence considering lane load disparities

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 877-894 doi: 10.1007/s11709-021-0756-2

摘要： Many bridge design specifications consider multi-lane factors (MLFs) a critical component of the traffic load model. Measured multi-lane traffic data generally exhibit significant lane disparities in traffic loads over multiple lanes. However, these disparities are not considered in current specifications. To address this drawback, a multi-coefficient MLF model was developed based on an improved probabilistic statistical approach that considers the presence of multiple trucks. The proposed MLF model and approach were calibrated and demonstrated through an example site. The model sensitivity analysis demonstrated the significant influence of lane disparity of truck traffic volume and truck weight distribution on the MLF. Using the proposed approach, the experimental site study yielded MLFs comparable with those directly calculated using traffic load effects. The exclusion of overloaded trucks caused the proposed approach, existing design specifications, and conventional approach of ignoring lane load disparity to generate comparable MLFs, while the MLFs based on the proposed approach were the most comprehensive. The inclusion of overloaded trucks caused the conventional approach and design specifications to overestimate the MLFs significantly. Finally, the benefits of the research results to bridge practitioners were discussed.

关键词： bridges     multi-lane factor     traffic load     lane load disparity     multi-truck presence     weigh-in-motion data    

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A multi-sensor relation model for recognizing and localizing faults of machines based on network analysis

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0736-9

摘要： Recently, advanced sensing techniques ensure a large number of multivariate sensing data for intelligent fault diagnosis of machines. Given the advantage of obtaining accurate diagnosis results, multi-sensor fusion has long been studied in the fault diagnosis field. However, existing studies suffer from two weaknesses. First, the relations of multiple sensors are either neglected or calculated only to improve the diagnostic accuracy of fault types. Second, the localization for multi-source faults is seldom investigated, although locating the anomaly variable over multivariate sensing data for certain types of faults is desirable. This article attempts to overcome the above weaknesses by proposing a global method to recognize fault types and localize fault sources with the help of multi-sensor relations (MSRs). First, an MSR model is developed to learn MSRs automatically and further obtain fault recognition results. Second, centrality measures are employed to analyze the MSR graphs learned by the MSR model, and fault sources are therefore determined. The proposed method is demonstrated by experiments on an induction motor and a centrifugal pump. Results show the proposed method’s validity in diagnosing fault types and sources.

关键词： fault recognition     fault localization     multi-sensor relations     network analysis     graph neural network    

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Hydromechanical model for hydraulic fractures using XFEM

Bo HE

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 240-249 doi: 10.1007/s11709-018-0490-6

摘要： In this study, a hydromechanical model for fluid flow in fractured porous media is presented. We assume viscous fluids and the coupling equations are derived from the mass and momentum balance equations for saturated porous media. The fluid flow through discrete cracks will be modelled by the extended finite element method and an implicit time integration scheme. We also present a consistent linearization of the underlying non-linear discrete equations. They are solved by the Newton-Raphson iteration procedure in combination with a line search. Furthermore, the model is extended to includes crack propagation. Finally, examples are presented to demonstrate the versatility and efficiency of this two-scale hydromechanical model. The results suggest that the presence of the fracture in a deforming, porous media has great impact on the fluid flow and deformation patterns.

关键词： multi-phase medium     porous     fracture     multi-scale method    

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Applying the multi-zone model in predicting the operating range of HCCI engines

Ming JIA, Maozhao XIE, Zhijun PENG,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 414-423 doi: 10.1007/s11708-010-0108-8

摘要： In this paper, a multi-zone model is developed to predict the operating range of homogeneous charge compression ignition (HCCI) engines. The boundaries of the operating range were determined by knock (presented by ringing intensity), partial burn (presented by combustion efficiency), and cycle-to-cycle variations (presented by the sensitivity of indicated mean effective pressure to initial temperature). By simulating an HCCI engine fueled with iso-octane, the knock and cycle-to-cycle variations predicted by the model showed satisfactory agreement with measurements made under different initial temperatures and equivalence ratios; the operating range was also well reproduced by the model. Furthermore, the model was applied to predict the operating range of the HCCI engine under different engine speeds by varying the intake temperatures and equivalence ratios. The potential to extend the operating range of the HCCI engine through two strategies, i.e., variable compression ratio and intake pressure boosting, was then investigated. Results indicate that the ignition point can be efficiently controlled by varying the compression ratio. A low load range can be extended by increasing the intake temperature while reducing the compression ratio. Higher intake temperatures and lower compression ratios can also extend the high load range. Boosting intake pressure is helpful in controlling the combustion of the HCCI engine, resulting in an extended high load range.

关键词： homogeneous charge compression ignition (HCCI) engine     multi-zone     operating range    

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Multi-timescale optimization scheduling of interconnected data centers based on model predictive control

《能源前沿（英文）》 doi: 10.1007/s11708-023-0912-6

摘要： With the promotion of “dual carbon” strategy, data center (DC) access to high-penetration renewable energy sources (RESs) has become a trend in the industry. However, the uncertainty of RES poses challenges to the safe and stable operation of DCs and power grids. In this paper, a multi-timescale optimal scheduling model is established for interconnected data centers (IDCs) based on model predictive control (MPC), including day-ahead optimization, intraday rolling optimization, and intraday real-time correction. The day-ahead optimization stage aims at the lowest operating cost, the rolling optimization stage aims at the lowest intraday economic cost, and the real-time correction aims at the lowest power fluctuation, eliminating the impact of prediction errors through coordinated multi-timescale optimization. The simulation results show that the economic loss is reduced by 19.6%, and the power fluctuation is decreased by 15.23%.

关键词： model predictive control     interconnected data center     multi-timescale     optimized scheduling     distributed power supply     landscape uncertainty    

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Evaluation of measurement uncertainty of the high-speed variable-slit system based on the Monte Carlo

Yin ZHANG, Jianwei WU, Kunpeng XING, Zhongpu WEN, Jiubin TAN

《机械工程前沿（英文）》 2020年 第15卷 第4期   页码 517-537 doi: 10.1007/s11465-020-0589-z

摘要： This paper presents a dynamic and static error transfer model and uncertainty evaluation method for a high-speed variable-slit system based on a two-dimensional orthogonal double-layer air-floating guide rail structure. The motion accuracy of the scanning blade is affected by both the moving component it is attached to and the moving component of the following blade during high-speed motion. First, an error transfer model of the high-speed variable-slit system is established, and the influence coefficients are calculated for each source of error associated with the accuracy of the blade motion. Then, the maximum range of each error source is determined by simulation and experiment. Finally, the uncertainty of the blade displacement measurement is evaluated using the Monte Carlo method. The proposed model can evaluate the performance of the complex mechanical system and be used to guide the design.

关键词： air-floating guide rail     error transfer model     driving and following structure     dynamic error     uncertainty evaluation     Monte Carlo method    

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A multi-scale model for CO

G. X. WANG, X. R. WEI, V. RUDOLPH, C. T. WEI, Y. QIN

《化学科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 20-25 doi: 10.1007/s11705-009-0138-0

摘要： This paper presents a multi-scale model to simulate the multicomponent gas diffusion and flow in bulk coals for CO sequestration enhanced coalbed methane recovery. The model is developed based on a bi-dispersed structure model by assuming that coal consists of microporous micro-particles, meso/macro-pores and open microfractures. The bi-disperse diffusion theory and the Maxwell-Stefan approach were incorporated in the model, providing an improved simulation of the CH —CO /CH —N counter diffusion dynamics. In the model, the counter diffusion process is numerically coupled with the flow of the mixture gases occurring within macro-pores or fractures in coal so as to account for the interaction between diffusion and flow in gas transport through coals. The model was validated by both experimental data from literature and our CO flush tests, and shows an excellent agreement with the experiments. The results reveal that the gas diffusivities, in particular the micro-pore diffusivities are strongly concentration-dependent.

关键词： multi-scale model     gas transport     coal     coalbed methane     CO2 sequestration    

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Mechanical design, modeling, and identification for a novel antagonistic variable stiffness dexterous

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0691-5

摘要： This study traces the development of dexterous hand research and proposes a novel antagonistic variable stiffness dexterous finger mechanism to improve the safety of dexterous hand in unpredictable environments, such as unstructured or man-made operational errors through comprehensive consideration of cost, accuracy, manufacturing, and application. Based on the concept of mechanical passive compliance, which is widely implemented in robots for interactions, a finger is dedicated to improving mechanical robustness. The finger mechanism not only achieves passive compliance against physical impacts, but also implements the variable stiffness actuator principle in a compact finger without adding supererogatory actuators. It achieves finger stiffness adjustability according to the biologically inspired stiffness variation principle of discarding some mobilities to adjust stiffness. The mechanical design of the finger and its stiffness adjusting methods are elaborated. The stiffness characteristics of the finger joint and the actuation unit are analyzed. Experimental results of the finger joint stiffness identification and finger impact tests under different finger stiffness presets are provided to verify the validity of the model. Fingers have been experimentally proven to be robust against physical impacts. Moreover, the experimental part verifies that fingers have good power, grasping, and manipulation performance.

关键词： multifingered hand     mechanism design     robot safety     variable stiffness actuator    

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标题 作者 时间 类型 操作

landscape classification using Chinese advanced high-resolution satellite imagery and an object-oriented multi-variablemodel

Li-gang MA,Jin-song DENG,Huai YANG,Yang HONG,Ke WANG

期刊论文

Mechanical responses of multi-layered ground due to shallow tunneling with arbitrary ground surface load

期刊论文

Performance design of a cryogenic air separation unit for variable working conditions using the lumpedparameter model

Jinghua XU, Tiantian WANG, Qianyong CHEN, Shuyou ZHANG, Jianrong TAN

期刊论文

Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault

Hamed HABIBI, Hamed RAHIMI NOHOOJI, Ian HOWARD

期刊论文

Development of machine learning multi-city model for municipal solid waste generation prediction

期刊论文

Simulation of cohesive crack growth by a variable-node XFEM

Weihua FANG, Jiangfei WU, Tiantang YU, Thanh-Tung NGUYEN, Tinh Quoc BUI

期刊论文

Amodified variable rate particle filter for maneuvering target tracking

Yun-fei GUO,Kong-shuai FAN,Dong-liang PENG,Ji-an LUO,Han SHENTU

期刊论文

A practical multi-lane factor model of bridges based on multi-truck presence considering lane load disparities

期刊论文

A multi-sensor relation model for recognizing and localizing faults of machines based on network analysis

期刊论文

Hydromechanical model for hydraulic fractures using XFEM

Bo HE

期刊论文

Applying the multi-zone model in predicting the operating range of HCCI engines

Ming JIA, Maozhao XIE, Zhijun PENG,

期刊论文

Multi-timescale optimization scheduling of interconnected data centers based on model predictive control

期刊论文

Evaluation of measurement uncertainty of the high-speed variable-slit system based on the Monte Carlo

Yin ZHANG, Jianwei WU, Kunpeng XING, Zhongpu WEN, Jiubin TAN

期刊论文

A multi-scale model for CO

G. X. WANG, X. R. WEI, V. RUDOLPH, C. T. WEI, Y. QIN

期刊论文

Mechanical design, modeling, and identification for a novel antagonistic variable stiffness dexterous

期刊论文