Lin W.-F.,Tianjin University |
Zhang B.-C.,Tianjin Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management
Proceedings of 20th International Conference on Industrial Engineering and Engineering Management: Theory and Apply of Industrial Engineering | Year: 2013
This paper discusses estimation of returns to scale (RTS) of Weak BCC inefficient DMUs in DEA. RTS generally has an ambiguous meaning if DMU is not on Weak BCC efficient frontier. Researchers adopt projection method for this problem. Theoretically, a Weak BCC inefficient DMU and its projection should exhibit the same RTS nature. Banker et al. (Eur J Oper Res 88:583-585, 1996b)'s projection, however, may give inconsistent estimation of RTS in some cases. For accurate RTS estimation of Weak BCC inefficient DMUs, this paper establishes Weak BCC projection and strong BCC projection. It is proved that, for a Weak BCC inefficient DMU, it is its Weak BCC projection that always exhibits the same RTS nature as itself while its strong BCC projection is not in some cases. In addition, Weak BCC projection is the most representative point among all frontier points for Weak BCC inefficient DMU. Therefore the projection should be Weak BCC projection, not strong BCC projection, when estimating RTS of Weak BCC inefficient DMUs. © Springer-Verlag Berlin Heidelberg 2013.
Dong J.,Civil Aviation University of China |
Wang J.,Civil Aviation University of China |
Wang A.,Civil Aviation University of China |
Jiang G.,Tianjin Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2012
Aircraft pushback and U-turn maneuvers belong to the special ground taxiing behaviors, and these behaviors are not accurately demonstrated in the current visual simulation system. In this paper, we study the position and attitude computational problems during aircraft pushback and U-turn maneuvers. From the perspective of airport tower control simulation, aircraft movement calculation methods constrained by nonholonomic kinematics are proposed to accurately describe aircraft pushback and U-turn maneuvers. The aircraft pushback motion algorithm suitable for simulation-driven calculation is designed according to aircraft actual movement and nonholonomic path following model. In addition, under the open-loop control, aircraft U-turn maneuver algorithm constrained by runway geometry and steering angle variation is designed to completely describe aircraft behaviors during runway U-turn. Compared with dynamics model, the methods we have proposed have the advantages of being easier to calculate and more suitable for visual simulation. The validity of these methods is verified by numerical simulation using aircraft geometry data.
Wang J.-N.,Air Traffic Management Research Base |
Wang A.-G.,Flight Test Center |
Jiang G.-Y.,Tianjin Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2014
For the 3D scene-driven design problem of apron service vehicle simulation system, a service vehicle kinematic model was established, which was simple-calculated and could drive real-time 3D scene simulation system. With simulating the three typical running behaviors of apron vehicle by Matlab software, the correctness and efficiency of the model were verified. Considering the operation characteristics of the apron service, a QT-based 3D scene driven model was designed by the proposed method. © right.
Zhang B.,Civil Aviation University of China |
Wang J.,Civil Aviation University of China |
Liu C.,Tianjin Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management |
Zhao Y.,Tianjin Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management
Journal of Air Transport Management | Year: 2012
This paper evaluates the technical efficiency of 37 Chinese airport airsides. We introduce take-off distance available, landing distance available, and aircraft-parking position as inputs into the efficiency evaluation. This study also estimates the input excess and output shortfalls. Benchmarks are identified for those technically inefficient airsides. © 2011 Elsevier Ltd.
Liu W.,Civil Aviation University of China |
Liu W.,Tianjin Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management |
Jiang N.,Tianjin University |
Jiang N.,Tianjin Key Laboratory of Modern Engineering Mechanics |
And 2 more authors.
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2013
The time sequence signals of instantaneous longitudinal, normal and spanwise velocity components at different vertical locations on the turbulent boundary layer over a flat plate were finely measured by constant temperature anemometry and double-sensor hot-wire probe in a wind tunnel. By the criteria of the module-maximum of locally averaged longitudinal velocity structure function, the conditional phase-averaged waveforms of different velocity components and Reynolds stress were detected during the burst. After disturbance, it is found that the friction coefficients and the Reynolds stress are reduced; the phase-differences between the phase-averaged waveforms of longitudinal vertical velocity and the spanwise velocity components are changed. When their phase differences are about odd times of π/2, the Reynolds stress is depressed to about zero. The mechanisms of production, diffusion and transportation of Reynolds stress are changed in wall-bounded turbulent flow and the Reynolds stresses are restrained to a certain degree.