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Song X.,Beihang University | Zhang Z.,Beihang University | Peng G.,Tsinghua University | Shi G.,Beijing Simulation Center
Physica A: Statistical Mechanics and its Applications | Year: 2017

Most pedestrian evacuation literatures are about routing algorithm, human intelligence and behavior etc. Few works studied how to fully explore the function of authority/security figures, who know more of the environment by simply being there every day. To evaluate the effect of authority figure (AF) in complex buildings, this paper fully investigates the AF related factors that may influence the evacuation effect of crowd, such as the number and locations of AFs, their spread of direction, calming effect and distribution strategies etc. Social force based modeling and simulation results show that these factors of AFs play important roles in evacuation efficiency, which means fewer AFs with right guiding strategy can have good evacuation performance. For our case study, Zhichun Avenue station, the conclusion is that deployment of four AFs is a good choice to achieve relatively high evacuation performance yet save cost. © 2016 Elsevier B.V.


Zhang L.,Beihang University | Luo Y.,Beihang University | Tao F.,Beihang University | Li B.H.,Beihang University | And 7 more authors.
Enterprise Information Systems | Year: 2014

Combining with the emerged technologies such as cloud computing, the Internet of things, service-oriented technologies and high performance computing, a new manufacturing paradigm - cloud manufacturing (CMfg) - for solving the bottlenecks in the informatisation development and manufacturing applications is introduced. The concept of CMfg, including its architecture, typical characteristics and the key technologies for implementing a CMfg service platform, is discussed. Three core components for constructing a CMfg system, i.e. CMfg resources, manufacturing cloud service and manufacturing cloud are studied, and the constructing method for manufacturing cloud is investigated. Finally, a prototype of CMfg and the existing related works conducted by the authors' group on CMfg are briefly presented. © 2014 Taylor and Francis Group, LLC.


Ren L.,Beihang University | Zhang L.,Beihang University | Zhang Y.-B.,Beihang University | Zhang Y.-B.,Beijing Simulation Center | And 2 more authors.
Jisuanji Jicheng Zhizao Xitong/Computer Integrated Manufacturing Systems, CIMS | Year: 2011

As a key technology of Cloud Manufacturing(CMfg), resource virtualization leveraged Internet of Things(IoT), Cyber-Physical System(CPS), and computing virtualization to achieve intelligent perception and control of all kinds of physical manufacturing resources, which could be transformed into logic resources so as to decouple physical elements from application services. Resource virtualization targeted to support a virtual service environment for CMfg with high efficiency, agility, reliability, security, and usability. Relevant technologies of CMfg resource virtualization were analyzed. And a layered framework for resource virtualization in CMfg was proposed. It was also pointed out that CMfg resource virtualization could realize overall resource sharing, obtain higher resource utilization rate and reduce energy consumption. It supported collaboration operation of multi-Agent with high reliability and security. It also provided satisfactory service operation environment for overall product lifecycle users.


Li T.,Beijing Simulation Center | Li B.-H.,Beihang University | Chai X.-D.,Beijing Simulation Center
Jisuanji Jicheng Zhizao Xitong/Computer Integrated Manufacturing Systems, CIMS | Year: 2012

According to the characteristics of multi-granularity resources sharing and simulation services establishment as well as its new demand on Simulation Service Description Framework(SSDF) in cloud simulation, a layered SSDF oriented to cloud simulation was proposed. The semantics of each layer in the framework were defined and formalized in OWL-S, and the researches were applied to the description of simulation services in certain cloud simulation system prototype. The proposed layered SSDF was verified by typical example. The result showed that the layered SSDF oriented cloud simulation was suitable for various multi-granularity simulation resources of cloud simulation system, and could described cloud simulation services in both attribute-semantic and model-semantic. Thus the intelligent discovery and automatic combination of simulation services were supported, and the construction of cloud simulation mode was realized.


Zhang Z.H.,Beihang University | Chai X.D.,Beijing Simulation Center | Hou B.C.,Beijing Simulation Center
Proceedings of the 2011 6th IEEE Conference on Industrial Electronics and Applications, ICIEA 2011 | Year: 2011

Cloud simulation is proposed currently as a new networked modeling and simulation mode, and it has attracted wide attention from both industrial and academic communities. There is an information assurance challenge and details of simulation must be guarded from unauthorized access. However, HLA provide little security mechanism. So the security threats of the HLA/RTI protocol were analyzed. In order to address these threats, security architecture for web-enabled HLA/RTI in the cloud simulation environment were proposed based on HTTPS and public key infrastructure (PKI) technique. There were two protocols of this platform: the security record layer protocol to provide data confidentiality and integrity services, the authentication protocol to provide authentication service based on PKI authentication framework. © 2011 IEEE.


Zhang Y.,Beihang University | Tao F.,Beihang University | Laili Y.,Beihang University | Hou B.,Beijing Simulation Center | And 2 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2013

The partner selection problem (PSP) in virtual enterprise has been comprehensively investigated from the aspects of research fields, contents, attributes or criteria been considered, and algorithms. With the consideration of environmental protection, the importance of "green criteria" in PSP is introduced, and two new green criteria, i.e., carbon emission and lead content in manufacturing production, are firstly brought into PSP. A formulation of PSP with green criteria is established which includes four objectives and six constraints. A new improved algorithm, named Pareto genetic algorithm for PSP (Pareto-PSGA), is designed for addressing the specific PSP. With Pareto solution ideas, vector encoding, random selection, two-point crossover, and single-point mutation for Pareto solutions are designed in the Pareto-PSGA. Experimental results demonstrate that compared with other typical intelligent algorithms such as simulated annealing and particle swarm optimization, Pareto-PSGA shows high performance in solving the specific PSP with more suitable Pareto solutions in shorter time. © Springer-Verlag London 2012.


Xie X.,Beihang University | Li B.,Beihang University | Chai X.,Beijing Simulation Center
Journal of Information Hiding and Multimedia Signal Processing | Year: 2015

Hyperspectral Imagery Sensing (HIS) is widely gained tremendous popularity in many research areas such as remotely sensed satellite imaging and aerial reconnaissance. HIS is an important technique with the measurement, analysis, and interpretation of spectra acquired sensing scene an airborne or satellite sensor. The development of sensor technology brought the developing of collecting image data using hyperspectral instruments with hundreds of contiguous spectral channels. The preprocessing of hyperspectral sensing data is a feasible way through machine learning technology. Among these machine learning methods, kernel learning is a feasible nonlinear feature extraction on hyperspectral sensing data. The nonlinear problems are solved with kernel function, and system performances such as recognition accuracy, prediction accuracy are largely increased. In this paper, we present a novel Kernel-Based Nonparametric Fisher Classifier (KNFC) for hyperspectral remote sensing imagery. Firstly, we have a comprehensive theoretical analysis on Nonparametric Discriminant Analysis. And NDA has its limitations on extracting the nonlinear features owing to the high nonlinear and complex distribution of the hyperspectral imagery data. In order to improve the limitation of NDA on hyperspectral remote sensing imagery, we introduce the kernel trick to NDA to develop Kernel-Based Nonparametric Fisher Classifier to enhance its ability on hyperspectral Imagery Sensing data. The feasibility of the KNFC is testified on the ORL and YALE databases, and then some experiments are implemented on two real data sets including Indian Pines and Washington, D.C. Mall, with various spectral and spatial resolutions reflecting different environments of remote sensing. © 2015 ISSN.


Xiao S.,Beihang University | Xudong C.,Beijing Simulation Center | Li Z.,Yunnan University | Guanghong G.,Beihang University
Simulation Modelling Practice and Theory | Year: 2010

This paper presents a modeling framework for product lifecycle information. Although being widely used in enterprises' virtual product data management, Product Lifecycle Management (PLM) systems are unable to manage the modeling and simulation aspects of virtual products. To reinforce the sharing and management of the product lifecycle information, especially the simulation data, a product's four-dimensional (4D) view model (PLIM) is established, which includes geometry view, task view, virtual prototype system view and lifecycle view. To provide efficient and effective simulation information, the prototype system view is then studied in detail. Finally, to validate the feasibility of the modeling framework, a prototype system is developed based on an application example, with the demonstration of 4D product lifecycle information model (PLIM). © 2010 Elsevier B.V. All rights reserved.


Ren L.,Beihang University | Zhang L.,Beihang University | Tao F.,Beihang University | Zhang X.,Pennsylvania State University | And 3 more authors.
Enterprise Information Systems | Year: 2012

Multidisciplinary design of complex products leads to an increasing demand for high performance simulation (HPS) platforms. One great challenge is how to achieve high efficient utilisation of large-scale simulation resources in distributed and heterogeneous environments. This article reports a virtualisation-based methodology to realise a HPS platform. This research is driven by the issues concerning large-scale simulation resources deployment and complex simulation environment construction, efficient and transparent utilisation of fine-grained simulation resources and high reliable simulation with fault tolerance. A framework of virtualisation-based simulation platform (VSIM) is first proposed. Then the article investigates and discusses key approaches in VSIM, including simulation resources modelling, a method to automatically deploying simulation resources for dynamic construction of system environment, and a live migration mechanism in case of faults in run-time simulation. Furthermore, the proposed methodology is applied to a multidisciplinary design system for aircraft virtual prototyping and some experiments are conducted. The experimental results show that the proposed methodology can (1) significantly improve the utilisation of fine-grained simulation resources, (2) result in a great reduction in deployment time and an increased flexibility for simulation environment construction and (3)achieve fault tolerant simulation. © 2012 Copyright Taylor and Francis Group, LLC.


Zhao M.-Y.,Beijing Institute of Electronic System Engineering | Wei M.-Y.,Beijing Institute of Electronic System Engineering | He Q.-R.,Beijing Simulation Center
Yuhang Xuebao/Journal of Astronautics | Year: 2010

For the missile controlled by the combination of lateral jet thrusters and aerodynamic fins, the control system is designed. The lateral jet thrusters can improve the response speed, but the structure of control system becomes more complex. Therefore, how to design control strategy properly is a urgent problem. For the aerodynamic fins controlled loop, a missile object with good performance is obtained by solving a minimum time control problem based on the concept of finite time stability. Furthermore, the lateral jet control law based on the backstepping approach is studied, and the control system with faster response can be achieved. In the whole process of design, the response property of the system is improved by adding an 'implicit angle-of-attack' feedback. Finally, the effectiveness of the proposed approach is validated by numerical simulation.

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