Yang X.-J.,Unit 63892 of PLA |
Yang X.-J.,Academy of Equipment Command and Technology |
Zeng L.,Academy of Equipment Command and Technology |
Zhang R.,Unit 63892 of PLA
International Journal of Uncertainty, Fuzziness and Knowlege-Based Systems | Year: 2012
Group decision making is an important category of problem solving techniques for complicated problems, among which the Delphi method has been widely applied. In this paper an improved Delphi method based on Cloud model is proposed in order to deal with the fuzziness and uncertainty in experts' subjective judgments. The proposed Cloud Delphi Method (CDM) describes experts' opinions by Cloud model and we aggregate the experts' Cloud opinions by synthetic algorithm and weighted average algorithm. Another key point of CDM is to stabilize and accommodate the individual fuzzy estimates by the defined stability rules rather than having to force them to converge, or reduce. The Cloud opinions and aggregation results can be exhibited in a graphically way leading experts to judge intuitively and it can decrease the number of repetitive surveys and/or interviews. Moreover, it is more scientific and easier to represent experts' opinion base on Cloud model which can combine fuzziness and uncertainty well. A numerical example is examined to demonstrate applicability and implementation process of CDM. © 2012 World Scientific Publishing Company.
Yang X.,Unit 63892 of PLA |
Yang X.,Academy of Equipment Command and Technology |
Yan L.,Unit 63892 of PLA |
Zeng L.,Academy of Equipment Command and Technology
Information Sciences | Year: 2013
In practice, many practical problems occur in uncertain environments, especially in situations that involve human subjective evaluation such as that in the analytic hierarchy process (AHP). This paper presents a practical multi-criteria group decision-making method for decision making under uncertainty. To handle the randomness and fuzziness of individual judgments, the normal Cloud model, group decision-making technique, and the Delphi feedback method are adopted. In the proposed Cloud Delphi hierarchical analysis (CDHA), experts are asked to express their judgments using interval numbers. Individual fuzziness and randomness are then mined from the interval-value comparison matrices. Subsequently, the interval-value pairwise comparison matrices are converted into the corresponding Cloud matrices, and the one-iteration Delphi process is executed to diminish individual judgment mistakes. The individual Cloud weight vectors are calculated using the geometric mean technique and are finally weighted to form the group Cloud weight vector. A simple case study that involved reproducing the relative area sizes of six provinces in China shows that the CDHA method can effectively reduce mistakes and improve decision makers' judgments in situations that require subjective expertise and judgmental inputs. In addition, a practical decision-making problem in which houses are ranked by home buyers shows that the proposed method is effective when applied to complex, large, multidisciplinary problems with considerable uncertainties. © 2012 Elsevier Inc. All rights reserved.
Zou Q.,Unit 63892 of PLA |
Chen Q.,Unit 63892 of PLA |
Zhang Y.,Unit 63892 of PLA |
Yuan C.,Unit 63892 of PLA |
Yuan S.,National University of Defense Technology
Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams | Year: 2013
According to the analysis of the characteristics of oscillation paths in the optical cavity of the unstable-resonator DF chemical laser, we point out that different oscillation paths of the upstream and downstream spectra will lead to certain difference in the emission spectrum. The emission spectrum of a continuous-wave DF laser was measured, and it is found that there is no significant difference in the major spectral line components, but some difference in the relative intensity of the upstream and downstream spectral lines. The spectral band of the upstream laser spot, namely the rotational quantum number at maximum relative intensity, tends to be in the direction of the low rotational quantum number for each spectral band. According to the measured spectrum, the cavity temperature and particle population ratio were estimated, and it is found that the average temperature of the upstream cavity is lower than that of the downstream cavity.
Fan Y.,Nanjing University of Aeronautics and Astronautics |
Han Y.,Nanjing University of Aeronautics and Astronautics |
Zhou C.,Unit 63892 of PLA
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010
GPS based spacecraft attitude autonomous determination technology is researched, and a Lyapunov stability theory based attitude control law with strong adaptivity and robustness is presented in the paper. A new strategy of spacecraft attitude autonomous determination technology is researched, which aligns two groups of baselines on the spacecraft. One group called short baselines resolves integer ambiguity since it's shorter than half of the carrier wave. The other group called long baselines is used to make up the shortages of shorter baseline based attitude determination precision. Adaptive and sliding mode variable structure controller with the stronger adaptability and robustness is designed considering uncertainty of inertia moment of spacecraft and outer disturbance torque. In the control process, an online uncertainty estimator corrects the parameters of sliding mode variable structure controller based on the adaptive law. Finally, numerical simulation about the integrated attitude closed loop composed of determination system and control system is executed on some section of spacecraft's orbit. The results of simulation sustain the effectiveness of the attitude determination and control algorithm presented in the paper. © 2010 Copyright SPIE - The International Society for Optical Engineering.
Zhang L.,National University of Defense Technology |
Liang D.,Unit 63891 of PLA |
Yao M.,Unit 63892 of PLA |
Zhang M.,Unit 63892 of PLA |
Zhang L.,Unit 63891 of PLA
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2013
As the influence of background radiation is not considered, traditional operating range equation of infrared search and track system (IRST) has a limit. In order to complete the equivalent calculation of operating range of IRST on small dynamic target rapidly in various meteorological and flight conditions, the operating range model on point target of IRST was derived in the sky background. Based on the equation, the operating range of one IRST on the target drone in all kinds of meteorological conditions was calculated. In addition, the equation was validated by the data of target drone flight test and it is proved that the equation is correct and can be used to the equivalent calculation of operating range of IRST. Finally, the operating range of IRST on one kind of missile under different flight and specifically meteorological conditions was calculated based on the equation.
Li H.,Postdoctoral Workstation of Unit 63880 of PLA |
Wu J.,Unit 63892 of PLA |
Zhu Z.,Unit 63892 of PLA |
Yin R.,Unit 63892 of PLA |
Dai W.,Unit 63891 of PLA
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2011
As the key components of laser terminal guided weapons (projectiles, bombs and missile), the performance of laser seeker directly influences acquisition, tracking capability and precision of target. Modeling and simulation of seeker based on computer simulation technology is an efficient method to evaluate its performance. With the mechanism characteristics of two-axis rate gyroscope stabilized seeker, the space stabilization and tracking principle of seeker was proposed and the mathematical model of servo system was established based on the multi-body kinetic and space flight theory. Simulation results shows the correctness of the model and expresses the stabilization and tracking principle of seeker, which lays the foundation for the trajectory simulation and set up of laser jamming mathematical simulation system.
Liu Y.,Henan Polytechnic University |
Wang Y.,Unit 63892 of PLA |
Meng F.,Henan Polytechnic University
Bandaoti Guangdian/Semiconductor Optoelectronics | Year: 2013
The non-linearity and dispersion characteristics of photonic crystal fiber (PCF) were investigated theoretically by adopting the multipole method. The numerical simulation results show that the two approaches can not only evidently increase the non-linearity of PCF, but also effectively extend the zero-dispersion wavelength λ0 in short-wavelength direction: one way is to decrease the hole diameter d but under the same ratio d/Λ; the other way is to increase the ratio d/Λ but under the same hole diameter d. The high non-linearity and flexible dispersion characteristics of PCF can provide preconditions for broadband and visible supercontinuum generation.
Bo J.,Unit 63892 of PLA |
Yan L.-L.,Unit 63892 of PLA |
Li W.,Unit 63892 of PLA
Proceedings - 2011 IEEE International Conference on Computer Science and Automation Engineering, CSAE 2011 | Year: 2011
Background subtraction methods are widely exploited for moving objects detection in surveillance video sequences acquired by static camera. Gaussian Mixture Model (GMM), whose convergence speed is rather slow, can be used to model the background of complex scene. This paper adds virtual Gaussian component into GMM and optimizes the updating process of parameters in GMM, in order to increasing the convergence speed of GMM. Experimental results show that our method can detect moving objects in complex scene correctly with fast convergence speed. © 2011 IEEE.
Wang Y.,Unit 63892 of PLA |
Qi F.,Unit 63892 of PLA |
Li H.,Unit 63892 of PLA |
Huang C.,Unit 63892 of PLA |
And 3 more authors.
Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams | Year: 2014
The regular circular fringes could be observed when the visible array CCD was irradiated by 532 nm pulsed laser from a distance of 31.5 m. Their generating conditions and mechanism have been investigated by changing the incident angle, the attenuation factor, repetition frequency and distance. The experimental results show that in the premise that the incident angle of laser is smaller or a little larger than the half angle of view 6.8°, the regular circular fringes can be observed as long as the power density can reach 10-3 W/cm2 at the pupil of optical system. It was proved that the regular circular fringes were caused by the diffraction effect of the pupil of optical system, based on the simulation of energy distribution on the detector's surface.
Li J.,State Key Laboratory of Complex Electromagnetic Environment Effect on Electronics Information Systems |
Zeng Y.,State Key Laboratory of Complex Electromagnetic Environment Effect on Electronics Information Systems |
Zhou B.,Unit 63892 of PLA |
Fu H.,Unit 63892 of PLA
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2013
Gesture consistency of airplane target between static and dynamics measurements was studied. The most common coordinate systems in target characteristics measurement were introduced, and the translation relationships were presented. The typical relative position relationship between line of radar sight and airplane target was analyzed, and the flow chart of gesture translation between static and dynamic measurements was derived. A simulation example was given. The airplane flew with a typical path, the radar track of airplane was simulated. The relative position relationship between line of radar sight and airplane target in polarization coordinate system and target coordinate system was derived while airplane is flying. The research can help to compare target characteristics between static and dynamic measurements rightly, and can also guide the dynamic simulation of target characteristics.