Xu A.-G.,CAS Beijing Institute of Applied Physics And Computational Mathematics |
Zhang G.-C.,CAS Beijing Institute of Applied Physics And Computational Mathematics |
Gan Y.-B.,North China Institute of Aerospace Engineering |
Chen F.,Linyi Normal University |
Yu X.-J.,CAS Beijing Institute of Applied Physics And Computational Mathematics
Frontiers of Physics | Year: 2012
In this mini-review we summarize the progress of Lattice Boltzmann (LB) modeling and simulating compressible flows in our group in recent years. Main contents include (i) Single-Relaxation-Time (SRT) LB model supplemented by additional viscosity, (ii) Multiple-Relaxation-Time (MRT) LB model, and (iii) LB study on hydrodynamic instabilities. The former two belong to improvements of physical modeling and the third belongs to simulation or application. The SRT-LB model supplemented by additional viscosity keeps the original framework of Lattice Bhatnagar-Gross-Krook (LBGK). So, it is easier and more convenient for previous SRT-LB users. The MRT-LB is a completely new framework for physical modeling. It significantly extends the range of LB applications. The cost is longer computational time. The developed SRT-LB and MRT-LB are complementary from the sides of convenience and applicability. © 2012 Higher Education Press and Springer-Verlag Berlin Heidelberg.
Cheng G.,North China Institute of Aerospace Engineering |
Chen X.,Beijing Oriental College
ICCRD2011 - 2011 3rd International Conference on Computer Research and Development | Year: 2011
In a visual driver-assistance system, vehicle detection is one of the major tasks. This paper presents a vehicle detection method based on multi-features fusion in the images acquired by a fisheye camera. The vehicle detection algorithm can be divided into three main steps: fisheye image calibration, generation of candidates with respect to a vehicle and verification of the candidates. In the fist step, a fisheye image calibration algorithm based on cylinder model is proposed for reproducing virtual scene. The second step determines vehicle candidates using features such as the shadow, symmetry and vertical edge. A precise symmetry axis location approach is introduced by combining edge symmetry axis, grey-level symmetry axis and S-channel symmetry axis in HSV color space. Furthermore, a nighttime vehicle detection algorithm is designed by detecting the headlights. And the last step determines whether the candidate is a vehicle or not by using wavelet decomposition for feature extraction and the Support Vector Machines (SVMS) for classification. Experimental results in different conditions, including sunny, rainy, and nighttime demonstrates that most vehicles can be detected and recognized with a high accuracy and a frame rate of approximately 16 frames per second on a standard PC. © 2011 IEEE.
Zhang J.Y.,North China Institute of Aerospace Engineering
Advanced Materials Research | Year: 2014
Based on the flexibility matrix method, the elastohydrodynamic lubrication performance of journal bearing are studied. Comparisons are made the effect of elastic deformation on the center orbit of connecting rod big end bearing. The results show that bearing eccentricity has far exceeded 1 near the maximum combustion pressure, considering the elastic deformation of connecting rod big end bearing, changing trend of bearing center orbit is the same at other times. © (2014) Trans Tech Publications, Switzerland.
Wang Y.,Yanshan University |
Li B.,North China Institute of Aerospace Engineering
Journal of Optical Communications and Networking | Year: 2010
An optical code-labeled router that performs packet forwarding through optical code label swapping (OCLS) based on code division multiplexing technology is proposed. It can enhance the processing speed of packets that can adapt to the growth of data and the aggregation of data service. The throughput of the router increases obviously since the optical code division multiplexing (OCDM) paths on the same wavelength can be processed in parallel. Moreover, it is attractive for its traffic control, bandwidth efficiency, protocol transparency, channel granularity, and so on. © 2010 Optical Society of America.
Yue Y.,North China Institute of Aerospace Engineering
Advanced Materials Research | Year: 2012
Tourism is often viewed as the availability of a clean natural environment without the pollution as the industry, but the hospitality industry, due to its very specific function, operating characteristics and services provided, consumes substantial quantities of energy, water and non-durable products. The resulting environmental impacts of hospitality facilities are thus characteristically greater than those caused by other types of buildings of similar size in China. In recognition of environmental degradation, governments, along with the green movement within the hospitality industry, and travellers, have become increasingly aware of the need for more effective measures to protect the environment. In order to achieve noticeable improvement, the managers and operators of the hospitality industry should be willing to act in an environmentally responsible manner. They also need to have adequate knowledge of the environmental issues pertinent to their activities, and sufficient funds to implement state-of-the-art environmentally sound practices. © (2012) Trans Tech Publications.
Zhou Y.,North China Institute of Aerospace Engineering
Advances in Mechanical Engineering | Year: 2015
Based on the surface piezoelectricity theory and first-order shear deformation theory, the surface effect on the axisymmetric wave propagating in piezoelectric cylindrical shells is analyzed. The Gurtin-Murdoch theory is utilized to get the nontraditional boundary conditions and constitutive equations of the surface, in company with classical governing equations of the bulk, from which the basic formulations are obtained. Numerical results show that the surface layer has a profound effect on wave characteristics in nanostructure at a higher mode. © 2015 SAGE Publications Ltd, unless otherwise noted. Manuscript content on this site is licensed under Creative Commons Licenses.
Liu L.,North China Institute of Aerospace Engineering
Mathematical Problems in Engineering | Year: 2014
Interval wavelet numerical method for nonlinear PDEs can improve the calculation precision compared with the common wavelet. A new interval Shannon wavelet is constructed with the general variational principle. Compared with the existing interval wavelet, both the gradient and the smoothness near the boundary of the approximated function are taken into account. Using the new interval Shannon wavelet, a multiscale interpolation wavelet operator was constructed in this paper, which can transform the nonlinear partial differential equations into matrix differential equations; this can be solved by the coupling technique of the wavelet precise integration method (WPIM) and the variational iteration method (VIM). At last, the famous Black-Scholes model is taken as an example to test this new method. The numerical results show that this method can decrease the boundary effect greatly and improve the numerical precision in the whole definition domain compared with Yan's method. © 2014 Liwei Liu.
Zhai Z.P.,North China Institute of Aerospace Engineering
Applied Mechanics and Materials | Year: 2014
This paper briefly describes the application of data mining technology on the personalized service in university library, and illustrate the importance of data mining for college library development through the analysis of its application in the library work in universities. © (2014) Trans Tech Publications, Switzerland.
Yue Y.,North China Institute of Aerospace Engineering
Journal of Chemical and Pharmaceutical Research | Year: 2015
It is belonged to the dynamic supply in the tourist supply, which constitutes the whole one together with food, lodging, purchases and other parts of the static supply of tourism products. In the three basic elements of modern tourism: tourists, tourism transportation, and travel means, the tourism transportation is an integral part of tourism. It is an important link linked with the tourist destinations and the location of tourists, by which it plays the role of a bridge and link between these two important parts. Tourism traffic is also belonged to the scope of the transport industry and other related industries. Therefore, the construction of tourism transport system with statistical information for tourism transportation and tourists, can improve the travel agency's rapid response capability, and accurate dynamic monitoring and implementation of security, which have a positive and important role. © 2015, Journal of Chemical and Pharmaceutical Research. All Rights Reserved.
Liu L.-W.,North China Institute of Aerospace Engineering
Advances in Mathematical Physics | Year: 2013
The Fokker-Planck-Kolmogorov (FPK) equation governs the probability density function (p.d.f.) of the dynamic response of a particular class of linear or nonlinear system to random excitation. An interval wavelet numerical method (IWNM) for nonlinear random systems is proposed using interval Shannon-Gabor wavelet interpolation operator. An FPK equation for nonlinear oscillators and a time fractional Fokker-Planck equation are taken as examples to illustrate its effectiveness and efficiency. Compared with the common wavelet collocation methods, IWNM can decrease the boundary effect greatly. Compared with the finite difference method for the time fractional Fokker-Planck equation, IWNM can improve the calculation precision evidently. © 2013 Li-wei Liu.