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Han W.,Aeronautics Computing Technique Research Institute | Han W.,Tsinghua University | Xie J.,Aeronautics Computing Technique Research Institute
Proceedings - 2014 10th International Conference on Computational Intelligence and Security, CIS 2014 | Year: 2015

FPGA is fit for large parallel programs. To improve the performance of EULER3D program, a PC+FPGA solution based on system generator was practiced. Based on the analysis of the algorithm's hotspot, a system model was built for EULER3D kernel algorithm constructed with system generator blocks. The data exchange between the PC and the FPGA board used the Gigabit Ethernet MAC interface, and the overall performance of the software improves a lot. The above method was compared to the manual HDL coding development method. The result shows that, with the help of system generator, it can reduce the development cycle and improve the efficiency. © 2014 IEEE.

Zheng Q.-Y.,Xidian University | Zheng Q.-Y.,Chang'an University | Liu S.-Y.,Xidian University | Liang Y.-H.,Aeronautics Computing Technique Research Institute
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2010

The DLR-F4 wing-body model is a simplified geometric simulation of current subsonic commercial aircraft intended to help evaluate simulations predicting aircraft drag. The accuracy of computed drag around it was investigated, and in particular, the effects of grid and turbulence models were analyzed. This was done by solving the Reynolds-averaged Navier-Stokes equations (RANS) coupled with the Spalart-Allmaras and Baldwin-Lomax turbulence models. A high quality multi-block structured patched grid around the wing-body configuration was generated using the hypercube concept. Mesh refinement was performed to investigate the effects of the grid's density. The results showed that computed lift was slightly affected by turbulence models and the grid's density. Computed drag was significantly affected by both turbulence models and the grid's density. The pressure coefficient distribution was slightly affected by the grid's density. This research showed that the accuracy of computed drag can be improved by decreasing the grid interval between the object plane and the first-layer mesh as well as by properly increasing the density of the grids.

Wei X.,Northwestern Polytechnical University | Dong Y.,Northwestern Polytechnical University | Ye H.,Aeronautics Computing Technique Research Institute
Proceedings - 2015 International Symposium on Theoretical Aspects of Software Engineering, TASE 2015 | Year: 2015

Quantitative verification is an effective technique for analyzing quantitative aspects of a safety critical system's design, and safety analysis is a significant aspect of safety critical system. However, they are often conducted separately. In this paper, we propose a new methodology, QaSten, fastens quantitative verification to safety analysis for Architecture Analysis and Design Language (AADL) model (including error model). QaSten formalizes a set of rigorous transformation rules that transform AADL model to PRISM model using formal method. In addition, QaSten can generate two safety property formulas automatically to check against the PRISM model for each hazardous state. Therefore, the occurrence probability of hazardous states can be calculated, which can help system designers understand the impact of parameters in the model. Furthermore, combining the probability and the severity of potential consequence of a hazardous state, QaSten determines the hazard risk acceptance level that can help engineers to identify critical hazard and modify or redesign architecture model to control it in an acceptable level. Two case studies, based on the Gas Leakage Alarm systems, are utilized to demonstrate QaSten's feasibility and effectiveness. © 2015 IEEE.

Zhang H.,Chang'an University | Yan H.,Aeronautics Computing Technique Research Institute
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2013

The accuracy of the drag prediction was investigated by simulating the transonic flow fields around the DLR-F6 wing-body (WB) and wing-body-nacelle-pylon (WBNP) configurations. The computations were performed using fully turbulence boundary-layer and fixed position transition boundary-layer respectively. Multiple sets of grids with different densities were then employed. The drag, drag increments by adding the nacelle and the pylon and the effects of grid and transition were also estimated. The results show that grid refinement leads to convergent results for two configurations, and the predicted surface pressure distributions on the wing and nacelle are in agreement with the experimental data. When comparing the experiment data, the predicted incremental drag was over estimated by about 3 drag counts, 0.000 3, but better than the results obtained by using other software. The computed results show that grid refinement had little effect on the wall surface pressure distributions, but obvious effect on drag, especially the pressure drag. Relative to the whole turbulence model, transition had obvious effect on drag, particularly on friction drag, but almost no effect on nacelle/pylon induced incremental drag.

Sun B.,Northwestern Polytechnical University | Dong Y.,Northwestern Polytechnical University | Ye H.,Aeronautics Computing Technique Research Institute
Proceedings - IEEE 9th International Conference on Ubiquitous Intelligence and Computing and IEEE 9th International Conference on Autonomic and Trusted Computing, UIC-ATC 2012 | Year: 2012

As the development of the large-scale and complicated software, especially in embedded system, nonfunctional properties of system, such as timing, reliability, safety and security, have become more and more important on impacting and restricting the behaviors of software system. One of the emerging challenges is how to test these properties in the phase of model-based software design. This paper aims to solve two essential problems in model-based testing: i) how to test model dynamically; ii) how to improve the efficiency of model-based testing. An enhancing adaptive random testing is investigated to generate test cases for AADL model-based testing in order to guarantee the system architecture and computing trustworthy. This methodology makes up the deficiency of adaptive random testing in dealing with the nonnumeric data. A case study is presented and illustrates that its efficiency is higher than traditional random testing. © 2012 IEEE.

Huang T.,Aeronautics Computing Technique Research Institute | Chen C.-S.,Aeronautics Computing Technique Research Institute
Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and Technology of China | Year: 2014

The paper focus on a real-time network, time-triggered Ethernet (TTE), which is used in safety-critical systems. The clock synchronization protocol related to the process of clock synchronization is researched and the permanence algorithm, compression algorithm, and clock synchronization service are analyzed. Then, the simulation platform including the switch model and node model is build. Finally the effectiveness and efficiency of time-triggered Ethernet clock synchronization are simulated and analyzed.

Wu T.,Northwestern Polytechnical University | Dong Y.,Northwestern Polytechnical University | Hu N.,Aeronautics Computing Technique Research Institute
Proceedings - 17th IEEE International Conference on Computational Science and Engineering, CSE 2014, Jointly with 13th IEEE International Conference on Ubiquitous Computing and Communications, IUCC 2014, 13th International Symposium on Pervasive Systems, Algorithms, and Networks, I-SPAN 2014 and 8th International Conference on Frontier of Computer Science and Technology, FCST 2014 | Year: 2015

This article presents a method to describe system requirements with B abstract machine, and transformation rules from B method to the Architecture Analysis and Design Language (AADL) model. We aim at solving the problems of requirements non-deterministic and ensuring requirements consistency during conversion procedure, AADL architecture model is consistent with requirements. Furthermore, in the early phrase of software development, various verification methods could be used to test software functional or nonfunctional attributes based on Model Driven Architecture (MDA). Firstly, we extract the subset of B method in this paper. Secondly, we describe this subset with formal method in terms of syntax and semantic. Thirdly, the derivation rules from B method to AADL model are proposed. The requirements consistency is then illustrated on a case study. © 2014 IEEE.

Lirong T.,Aeronautics Computing Technique Research Institute | Ming M.,Aeronautics Computing Technique Research Institute
SAE Technical Papers | Year: 2015

In recent year, with the booming of Chinese economy and domestic civil air transportation market, China's aircraft manufacturers have been trying to develop their own commercial aircraft and changing from the subcontracting-manufacturer to aircraft developer, which turned to be a very hard task. One of the main challenges in front of China's aircraft manufacturers and airborne equipment suppliers is how to apply the airworthiness standards, such as ARP4754A, ARP4761, DO-178B(C) and DO-254, etc, into their engineering practice. Chinese companies are struggling in improving their capabilities to satisfy certification requirements and are making some remarkable progress these years. The paper first introduces the current status of Chinese aviation industry, and then the challenges to China's airborne equipment suppliers are analyzed. Based on these, the customization considerations of airworthiness standards and ARP4754 Practice in Chinese context are discussed. Copyright © 2015 SAE International.

Zheng Q.,Xidian University | Zheng Q.,Chang'an University | Liu S.,Xidian University | Zhou T.,Aeronautics Computing Technique Research Institute
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | Year: 2010

The accuracy of computed drag around the DLR-F6 wing body configuration and the effects of grid and turbulence models on the aerodynamic characteristics are investigated by solving Reynolds-averaged Navier-Stokes (RANS) equations coupled with three kinds of turbulence models- the Spalart-Allmaras (SA) one equation model, the Wilcox's k-ω model, and the Menter's k-ω SST model. A multi-block structured patched grid provided by the AIAA Drag Prediction Workshop is employed in the computation. The computational results show that the pressure distributions on the wing surface agree well with the experiment. The varying trends of the computed aerodynamic forces with the angle of attack are consistent with the experiment. Grid refinement leads to convergent results for Spalart-Allmaras model, and the drag gets better than those from other softwares. The different turbulence models exert certain effects on the pressure distributions, especially on the positions of shock wave; a little effects on lift; and obvious effects on drag, especially friction drag. The turbulence models also exert effects on the flow separation near the root of wing. In the transonic flow computations, the Menter's k-ω SST model achieves the highest accuracy.

Cui X.,Xidian University | Cui X.,Aeronautics Computing Technique Research Institute | Yang J.,Xidian University
Proceedings - 2012 International Conference on Computer Science and Information Processing, CSIP 2012 | Year: 2012

As the networks have been broadly used everywhere such as national defense, military, bank and so on, security of data transported on network has become a hot issue. Public key cryptographic algorithms are widely applied in network communication. RSA has been used for a long time as a traditional public key cryptographic system, but it seems not able to meet user's higher security demands. In recent years, ECC(Elliptic Curve Cryptography) has been adopted more and more broadly because of its highest security of the same length bit. In addition, it also has the advantage of less computation overheads, less bandwidth demand and so on. The speed of encryption and decryption of ECC is greatly affected by point multiplication, which is very time-consuming. In this study, an FPGA(Field Programmable Gate Array) based processor is implemented for ECC, which parallelizes the computing of ECC at bit-level and gains a considerable speed-up. The ECC processor is fully implemented with hardware which supports key length of 113-bit, 163-bit and 193-bit. Algorithms suitable for hardware implementation are applied to make the processor more efficient. There are four kinds of unit in the processor: arithmetic logic unit, controlling unit, and input/output system. The units communicate with each other thought bus in FPGA device. © 2012 IEEE.

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