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He Z.,Harbin Institute of Technology | Wang G.-X.,Harbin Institute of Technology | Meng F.-W.,Northeast University at Qinhuangdao Campus
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2015

A new design method for nonlinear H∞ control was proposed. Though sum of squares (SOS) method can be used to solve analytically unsolvable nonlinear problems, but it still cannot be used directly to solve the Hamilton-Jacobi-Issacs (HJI) inequality or the nonlinear bounded-real inequality. The restrictions of the SOS method were discussed in detail. An iterative design procedure for nonlinear H∞ control problems was presented. There are two steps in each round of iteration. The first step is to design the nonlinear state feedback with adjustable gain matrix by using the SOS method. The second step is to solve an optimal problem in computation of the L2-gain by using a graphical-analytical method. A nonlinear H∞ control design for large attitude maneuvers of statellites was presented as an application example of the proposed method. ©, 2014, Editorial Department of Electric Machines and Control. All right reserved.


Yuan H.,Northeast University at Qinhuangdao Campus | Wang D.,Shenyang University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

The paper present a new approach of calculating the shortest paths, the approach was named as SPM (the shortest paths' matrix). Compared to the past approaches, SPM introduced distances into a matrix and could show activity distances directly in elements of the matrix and improved efficiency. The definition, operating rules of SPM and others related to SPM were described in this paper. At the end, the approach was applied to practical processes, the shortest paths were found out quickly. The approach provided a new resolution to the calculation of the shortest paths. © 2010 Springer-Verlag.


Huilin Y.,Northeast University at Qinhuangdao Campus | Wang D.,Shenyang University
Proceedings - 2010 International Conference on Management of e-Commerce and e-Government, ICMeCG 2010 | Year: 2010

The new approach in this paper added role factor in the activity-section flow chart and proposed human-computer interactive, role-exchanged concept. It is used in a logistics system, remove the activity loops and reduce interactive times between sections or roles, so it is more suitable for electronic business process than before. © 2010 IEEE.


Zhang M.,China University of Mining and Technology | Li G.,Northeast University at Qinhuangdao Campus | Mu H.L.,Dalian University of Technology | Ning Y.D.,Dalian University of Technology
Energy | Year: 2011

This paper aims at analyzing energy and exergy efficiencies in the Chinese transportation sector. Historical data is used to investigate the development of efficiencies from 1980 to 2009. Firstly, we calculate energy consumption values in PJ (petajoule) for nine transportation modes of five transportation sub-sectors. Then, the weighted energy and exergy efficiencies for each transportation mode, calculated by multiplying weighting factors with efficiency values of that mode, are summed up to calculate the weighted mean overall efficiencies for a particular year. We find that: (1) In 2009, the energy consumed in transportation sector was 12179.80 PJ, whereas that was 589.25 PJ in 1980. (2) Highways transport was the biggest energy consumer, which consumed 82.0% of total transport energy consumption in 2009. (3) Up to 2009, the oil consumed by transportation accounted for 75.1% of that in the whole country, which is more than the net oil import. (4) The average overall energy and exergy efficiencies are found to be 21.22% and 19.95%, respectively. (5) A comparison with other countries showed that energy and exergy efficiencies of the Chinese transportation sector are slightly lower than those of Jordan, Malaysian, Saudi Arabian and Norwegian, and higher than that incurred in Turkish. © 2010 Elsevier Ltd.


Zhai Y.-J.,Liverpool John Moores University | Yu D.-W.,Northeast University at Qinhuangdao Campus | Guo H.-Y.,Zhejiang University | Yu D.L.,Liverpool John Moores University
Engineering Applications of Artificial Intelligence | Year: 2010

Current production engines use look-up table and proportional and integral (PI) feedback control to regulate air/fuel ratio (AFR), which is time-consuming for calibration and is not robust to engine parameter uncertainty and time varying dynamics. This paper investigates engine modelling with the diagonal recurrent neural network (DRNN) and such a model-based predictive control for AFR. The DRNN model is made adaptive on-line to deal with engine time varying dynamics, so that the robustness in control performance is greatly enhanced. The developed strategy is evaluated on a well-known engine benchmark, a simulated mean value engine model (MVEM). The simulation results are also compared with the PI control. © 2009 Elsevier Ltd. All rights reserved.


Yan T.,Yanshan University | Yu E.,Yanshan University | Zhao Y.,Northeast University at Qinhuangdao Campus
Materials and Design | Year: 2013

The hot deformation behavior of 55SiMnMo bainite steel was studied through isothermal hot compression tests conducted using a Gleeble 3500 at 950-1100°C, with strain rates of 0.01s-1 to 10s-1. A constitutive equation was established using the experimental results to describe the stress-strain relationship based on the dislocation density variation, considering the influence of the dynamic softening mechanism. When dynamic recovery is the only softening mechanism, a constitutive equation for flow stress was obtained from the variation of the dislocation density during hot deformation based on work hardening and dynamic recovery. When dynamic recrystallization occurs, the relationship between the dislocation density and the volume fraction of dynamic recrystallization was used to predict the flow stress after the peak. The reliability of the model was verified through a comparison between the predicted flow stress curves from the model and the experimental data. © 2013 Elsevier Ltd.


Liu H.,Yanshan University | Liu F.,Yanshan University | Hou D.,Northeast University at Qinhuangdao Campus | Shi P.,Yanshan University
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2012

Considering the role of nonlinear elastic constraint of the hydraulic pressure cylinder and compensating cylinder in the four-high rolling mill process, a multi-segmented nonlinear vibration dynamic equation of rolling mill rolls is established. Averaging method is used to get frequency response equation of the system, singularity theory is applied to analysis it and then 6 group transition sets and bifurcation diagrams are obtained, which show the various bifurcation forms of this system. The actual parameters of rolling mill is used to analyze the impact law that every nonlinear parameter on vibration characteristics of this system, after the numerical simulation the characteristics that the amplitude-frequency characteristic curves both show turning to the high frequency in each segment are found. Choosing proper system parameter can restrain this behave effectively, which provides a theoretical basis to suppress vibration of rolling mill rolls. © 2012 Journal of Mechanical Engineering.


Liu F.,Yanshan University | Liu B.,Yanshan University | Shi P.,Yanshan University | Hou D.,Northeast University at Qinhuangdao Campus
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2014

With four-high plate mill as an example, two nonlinear constraints that are segmented elastic force and friction force of hydraulic screw-down cylinders and bending cylinders in rolling mill roll system vibration are analyzed, the model that nonlinear roll system vibration under the nonlinear constraint action from hydraulic cylinder is established, and amplitude-frequency response of the vibration system is obtained by using average method. The behavior characteristic of roll system under the action of segment elastic force and friction force is studied by analysis of vibration curves under the function produced by two kinds of nonlinear factors. The law of amplitude-frequency characteristics of roll system influenced by two kinds of nonlinear factors respectively is studied by taking different segmented elastic force and friction force. The results show that vibration speed is affected by the magnitude of elastic force, the instability frequency area is wider with increases of segmented elastic force increasing, and the influence on the vibration behavior of the roll system turns damping into nonlinear with friction force increasingly. This conclusion provides a theory reference for roll system vibration control. © 2014 Journal of Mechanical Engineering.


Wang G.,Northeast University at Qinhuangdao Campus
Applied Mechanics and Materials | Year: 2014

New urbanization is an important feature of China's development. The development of urbanization has a far-reaching effect on the building materials industries. The development of the building materials industries is closely interrelated with all of the national economy, and it is obviously affected by macro economy and investment in the fixed assets. In the national economy, building materials industries is an important basic one, and plays an important role in the course of the industrialization and urbanization of our country. Urbanization needs to speed up the upgrade of the building materials industries transition, and come true the new Chinese-style industry. In the building materials industries, there are still many problems, such as Low-level competition, high pressure in eliminating the backward, and so on. The building materials industries provide an important material foundation to fixed assets investment of the urbanization. © (2014) Trans Tech Publications, Switzerland.


Liu T.,Northeast University at Qinhuangdao Campus
Computers and Mathematics with Applications | Year: 2016

By introducing the wavelet multiscale method and the homotopy method to the inversion process for the parameter identification problem of partial differential equations, a joint inversion method called the wavelet multiscale-homotopy method is proposed, which is globally convergent, computationally efficient, and has the anti-noise ability. As a practical problem, the parameter identification problem of the saturation equation in the fractional flow formulation of the two-phase porous media flow equations is solved. Numerical results validate the method's merits. © 2016 Elsevier Ltd.

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