航空发动机变结构全局快速Terminal滑动模态控制方法研究

针对航空发动机这个具有时变不确定性的非线性系统,提出了一种新型变结构全局快速最终滑动模态控制(Variable Structure Global Fast Terminal Sliding Mode Control)的航空发动机控制方法;通过对利用VSGFTSMC理论设计航空发动机最终滑动模态控制器的方法进行了深入研究,设计了航空发动机变结构全局快速滑动模态控制器;仿真结果表明,所设计的控制器的控制效果良好,对外界干扰有很强的抑制能力,使被控系统在整个控制阶段都具有较强的鲁棒性.     

加油站库存信息采集与管理系统

为了提高石油公司对下属加油站库存的管理问题,设计了加油站库存信息采集与管理系统,系统分别由油罐液位仪、加油站管理主机和上级石油运营公司三级组成;油罐液位仪负责采集加油站各油罐内的油位并通过CAN总线发送给管理主机;管理主机接收来自各油罐监液位的数据,经过处理、统计分析、显示并存储到数据库ACCESS2003里;石油运营公司与加油站主机通过TCP/IP网络连接进行数据交互,获取各加油站的库存和销售速度等信息;经过对某加油站内8个椭圆型储油罐进行实验,得出了各油罐内传感器的输出电压、液位高度和剩余油量等数据,并且根据销售油速预测出了断油时间,能够达到及时油品配送的目的,避免断油事故的发生。     

基于FPGA的MEMS陀螺仪SAR150实时数据采集系统设计

针对传统MEMS陀螺仪输出信息为模拟量且易受干扰、噪声较大的问题,结合SAR150陀螺仪可以直接输出数字信号的特点,提出了一种新型的数字陀螺仪实时数据采集系统;该系统以FPGA为主控制器,通过SPI接口完成对MEMS陀螺仪SAR150的控制与数据的传输,实现了对陀螺仪输出信号的采集、实时传输及存储;通过将所研制的数据采集系统应用于SAR150陀螺仪测量角速率实验,并对测得数据进行误差分析,实验结果表明:数据采集系统采集输出的角速率值与理论值的绝对误差标准差均小于0.2°/s;且该系统的可靠性高、实时性好,为后续的陀螺仪测试及标定奠定了基础,有一定的工程应用价值。     

STM32F207和DM9161A的以太网实现方案

电力抄表系统常通过网络采集和传输电网中的谐波等信息。本文提出了一种适合电力系统的网络设计方案。在STM32F207和DM9161A为核心的硬件平台上,完成了LwIP协议栈的移植,实现了远程终端和上位机通信。使电力系统更具实时性与交互性,并保证了通信的可靠性。     

Example-based automatic music-driven conventional dance motion synthesis

We introduce a novel method for synthesizing dance motions that follow the emotions and contents of a piece of music. Our method employs a learning-based approach to model the music to motion mapping relationship embodied in example dance motions along with those motions' accompanying background music. A key step in our method is to train a music to motion matching quality rating function through learning the music to motion mapping relationship exhibited in synchronized music and dance motion data, which were captured from professional human dance performance. To generate an optimal sequence of dance motion segments to match with a piece of music, we introduce a constraint-based dynamic programming procedure. This procedure considers both music to motion matching quality and visual smoothness of a resultant dance motion sequence. We also introduce a two-way evaluation strategy, coupled with a GPU-based implementation, through which we can execute the dynamic programming process in parallel, resulting in significant speedup. To evaluate the effectiveness of our method, we quantitatively compare the dance motions synthesized by our method with motion synthesis results by several peer methods using the motions captured from professional human dancers' performance as the gold standard. We also conducted several medium-scale user studies to explore how perceptually our dance motion synthesis method can outperform existing methods in synthesizing dance motions to match with a piece of music. These user studies produced very positive results on our music-driven dance motion synthesis experiments for several Asian dance genres, confirming the advantages of our method.     

Extension of the DEMATEL method in an uncertain linguistic environment

The decision making trial and evaluation laboratory (DEMATEL) method is a useful tool for analyzing correlations among factors using crisp values. However, the crisp values are inadequate to model real-life situations due to the fuzziness and uncertainty that are frequently involved in judgments of experts. The aim of this paper is to extend the DEMATEL method to an uncertain linguistic environment. In this paper, the correlation information among factors provided by experts is in the form of uncertain linguistic terms. A formula is first presented to transform correlation information from uncertain linguistic terms to trapezoidal fuzzy numbers. Then, we aggregate the transformed correlation information of each expert into group information using the operations of trapezoidal fuzzy numbers. The importance and classification of factors are determined via fuzzy matrix operations. Furthermore, a causal diagram is constructed to vividly show the different roles of factors. Finally, an example is used to illustrate the procedure of the proposed method.     

Design optimization of supersonic jet pumps using high fidelity flow analysis

Supersonic jet pumps are simple devices with no moving parts, where a high velocity (primary) flow is used to pump a second fluid. In this paper, Computational Fluid Dynamics (CFD) is combined with an optimization framework in order to develop a tool for the rapid generation of jet pump designs. A key feature of the problem formulation is the transformation of the jet pump design parameters in terms of geometric ratios. This approach dramatically reduces the number of unrealistic designs covered by the Design of Experiments. Optimal Latin Hypercubes for surrogate model building and model validation points are constructed using a permutation genetic algorithm and design points are evaluated using CFD. Surrogate models of primary and entrained flow rates are built using a Moving Least Squares approach. A series of optimizations for various pump sizes are performed using a genetic algorithm and Sequential Quadratic Programming, with responses calculated from the surrogates. This approach results in a set of optimized designs, from which pumps for a wide range of flow rates can be interpolated.     

多目标多约束的集成电路统计优化策略

对于集成电路设计、生产过程中的多目标、多约束统计优化问题,本文提出了“合格率足够高”的优化宗旨,并从概率论的基本原理出发,结合集成电路的特点,导出了一种合格率的近似表述方法,提出的变权重Monte Carlo法编程简便,效率高。采用这些优化策略设计的集成电路合格率优化系统取得了比较好的结果。     

Effect of nitrogen and nickel on the stability of an Fe-12Cr-23Mn austenitic steel

The effect of nitrogen and nickel on the austenite stability and the structural changes as a result of cold work of an Fe-12Cr-23Mn alloy steel has been examined by transmission electron microscopy and X-ray analysis. Prestrain was performed either at room temperature or at 200° C. Final strain was carried out at liquid nitrogen temperature. The volume fraction of strain-induced martensite decreased by 40% and 12% due to the addition of 2.43% Ni and 0.11% N, respectively, despite whether prestrain was performed or not. The mechanisms are discussed in terms of the phase, stacking faults, dislocation cells and dislocation tangles induced by prestrain and final strain.     

Stability and work hardening of an Fe-12Cr-23Mn austenitic steel

The effect of pre-strain on the strain-induced martensitic transformation of an Fe-12Cr-23Mn austenitic steel has been investigated through transmission electron microscopy and X-ray analysis. Pre-strain was performed either at room temperature or at 200° C. Final strain was carried out at liquid-nitrogen temperature. The phase was shown to form on {1 1 1} planes of the austenite matrix predominantly by overlapping of stacking faults. The martensite transformation sequence was . Nucleation of the phase mainly occurred at intersections of bands. Austenite stability was shown to increase by pre-strain at 25° C or 200° C. Pre-strain at 200° C has a greater effect on austenite stability than does pre-strain at 25° C. The mechanism was discussed in terms of martensite transformation rate and various substructures introduced during straining. Work hardening was shown to depend on the degree of pre-strain and final strain. The correlation between work hardening and substructures introduced during straining was examined.