考虑工序外协的TOC产品组合优化研究

 针对 “粗粒度”产品外包或自制模式进行能力拓展时造成的产品规划保守和接单损失问题,采用“细粒度”工序外协模式对瓶颈、非瓶颈有区别地进行产能提升,使企业设备平均利用率最高、整体有效产出最优、市场需求满意度最好。从自制商和外协商两种角度定义了有效产出,并推导了工序外协和产品外包两种不同制造模式下有效产出的关系。基于传统和新型两种约束理论（TOC）运作逻辑,根据独立优化和集成优化两种优化策略,构建了考虑工序外协的两种TOC产品组合优化数学模型。分析了工序外协和自制/外包模型间的关系,并进行了数学证明。若单位产品的外包成本等于所有工序外协的累加成本,则同一制造模式下集成优化策略不差于独立优化策略,同一优化策略下工序外协制造模式不差于产品外包制造模式。最后通过单瓶颈、多瓶颈算例分析验证了模型以及定理的有效性。     

分布式航空电子系统信息传输机构设计研究

 航空电子系统日益增长的复杂性使其必须走向分布式处理的道路。本文介绍一个基于1553B总线的分布式航空电子系统的实验模型——EPDAS系统,讨论了EPDAS系统信息传输机构的有关组成部分:总线通信协议、通信管理软件和总线接口,本文在分析传统的同步总线控制方式的缺点之后,提出了询问和命令/响应相结合的总线控制方式,该方式能提高总线传输的效率和实时性。在EPDAS系统的总线接口设计中,引入了流水线并行处理技术,解决了总线接口的瓶颈问题,并使之易于VLSI化;伪DMA控制的概念,使总线接口电路更加简化;共享存贮器的互连技术,具有效率高、控制简单、容易实现等优点。EPDAS系统结构合理、效率高,符合国情、适合于新一代的飞机。     

Variable slip window technology in transition detection on pitching airfoil

In the pitching motion, the unsteady transition and relaminarization position plays an important role in the dynamic characteristics of the airfoil. In order to facilitate the computer to automatically and accurately calculate the position of the transition and relaminarization, a Variable Slip Window Technology (VSWT) suitable for airfoil dynamic data processing was developed using the S809 airfoil experimental data in this paper and two calculation strategies, i.e., global strategy and single point strategy, were proposed: global strategy and single point strategy. The core of the VSWT is the selection of the window function h and the parameters setting in the h function. The effect of the VSWT was evaluated using the dimensionless pulse strength value (INB), which can be used to evaluate the signal characteristics, of the root mean square (RMS) value of the fluctuating pressure. It is found that: the h function characteristics have a significant influence on the VSWT. The suitable functions are H_n function constructed in this paper and step function. For the left boundary of the magnified area, the step function can obtain the largest INB value, but the robustness is not good. The H₁ function (Gaussian-like function, n = 1) can show higher robustness while ensuring a large INB value. The two computing strategies, which are single point strategy and global strategy, have their own advantages and disadvantages. The former strategy, that is the single point strategy, can achieve a higher INB value, but the RMS magnification at the feature position needs to be known in advance. Although the INB value obtained by the latter strategy, that is the global strategy, is slightly smaller than the calculation results of the former strategy, it is not necessary to know the RMS magnification at the feature position in advance. So the global strategy has better robustness. The experimental data of NACA0012 airfoil was used to further validate the developed VSWT in this paper, and the results show that the VSWT developed in this paper can still double the INB value of the transition/relaminarization position. The VSWT developed in this paper has certain practicability, which is convenient for the computer to automatically determine the transition/relaminarization characteristics.     

基于Gauss伪谱法的UCAV对地攻击武器投放轨迹规划

研究无人作战飞机(UCAV)在对地攻击阶段的武器投放轨迹规划问题.针对传统方法在处理复杂的飞行器运动学、动力学约束上存在的困难,提出了一种基于Gauss伪谱法(GPM)的求解策略.首先,为了最大程度地逼近实际飞行环境,对UCAV的气动力特性、发动机推力特性、油耗特性及大气环境特性进行了高精度拟合,并充分考虑了飞行器各种...     

分层结构的雷达告警设备软件测试方法

雷达告警设备是现代作战飞机不可或缺的雷达对抗设备,主要用于对敌方雷达威胁信号的告警.分析了分层结构的雷达告警设备软件的特点,借鉴集成测试中自底向上增量式集成策略,提出了一种综合运用调试、插桩和仿真的配置项测试方法.测试结果表明,方法对此类以数据处理功能为核心、分层结构设计的嵌入式软件测试,有很好的借鉴作用.     

自动铺带机预浸带精密输送控制技术

 根据自动铺带（ATL）成型工艺对预浸带输送系统的要求,经运动学和动力学分析,建立预浸带输送的数学模型;提出一种适应于预浸带输送的精密控制策略,并采用模型参考自适应控制方式实现预浸带的精密控制;经SIMULINK仿真研究表明,自适应控制器满足预浸带精密输送控制系统的性能要求。     

Multiband coherent radar detection against compound-Gaussianclutter

A Multiband GLRT-LQ (Generalized Likelihood Ratio Test-Linear Quadratic), MBGLRT-LQ, detector is derived for the coherent radar target detection against a compound-Gaussian clutter background. This scheme is an extension to the multiband case of the Asymptotically Optimum Detector (AOD), also derived under the name of GLRT-LQ in. The proposed multiband version of the algorithm shows two main advantages with respect to the original single-band algorithm. 1) For the adaptive implementation, it requires a much smaller area of homogeneous clutter echoes to estimate the covariance matrix of the interference; 2) it provides an optimum processing of the radar echoes when the radar operates in frequency agility, as electronic counter-countermeasure (ECCM) strategy. A closed form performance analysis is provided for the MBGLRT-LQ detector, which is used to compare it with the single-band version. An application to live recorded data is also presented to validate the obtained results     

相控阵主动雷达导引头波形策略

针对高脉冲重复频率脉冲多普勒(HPRF-PD)体制的相控阵主动雷达导引头中存在的距离遮挡问题,设计了一种新的波形选择策略。首先,利用提出的脉冲重复频率(PRF)波形选择策略,离线计算得到距离对应PRF的波形查找表。然后,通过叉积自动频率控制环路滤波(CPAFCLF)算法预估下个相参处理间隔(CPI)导引头与目标间的径向相对速度,并联合提出的基于Sage-Husa带有速度预测的自适应"当前"统计模型(SH-ACSMVP)算法得到的距离跟踪值,获得下个CPI的距离预测值。在跟踪机动目标场景中,相比于"当前"统计(CS)模型跟踪算法及基于"当前"统计模型的自适应无迹卡尔曼滤波(CAUKF)算法,本文算法得到的距离预测误差更小,误差收敛速度更快。根据此距离预测值从波形查找表中选择波形发射,作为下个CPI的发射波形,实现后续跟踪阶段的抗距离遮挡,提高目标跟踪性能。仿真结果表明了本文所设计波形选择策略的正确性及有效性。     

基于Radau伪谱方法的轨迹优化

研究了导弹在末制导阶段满足多约束条件下的轨迹优化问题。针对传统方法在处理复杂的非线性运动学、动力学约束上存在的困难,提出了一种基于Radau伪谱方法(RPM)的求解策略。首先,给出了考虑导弹速度和空气密度变化、终端和过程约束条件以及2种不同的性能指标函数的最优轨迹优化问题;其次,利用RPM将轨迹优化问题转化为非线性规划问题,采用序列二次规划算法求得最优解;最后,分2种初始条件对最大落角和最大终端速度的轨迹优化问题进行了仿真验证,结果表明:本文方法能够在较短的时间内生成一条满足多种约束要求的高精度的最优轨迹。     

基于云蚁群算法的高效节能氩弧焊工艺参数优化研究

为在氩弧焊加工过程中提升效率的同时降低能耗,研究了一种氩弧焊高效节能工艺参数的多目标优化模型及算法。首先确定了以焊接速度及焊接电流为优化变量,在综合考虑焊接设备、工件特性、操作方法及焊接质量等约束的前提下,建立了以最小电能消耗以及最短加工时长为优化目标的多目标工艺参数优化模型;提出一种基于云模型的蚁群算法(CBACO)以对所构建的优化模型进行求解,其中包含一种适当的编码方式、一种局部与全局相结合的探索策略、一种基于云模型的变异因子、传统的单点交叉因子、单形交叉因子以及适当的选择策略;通过一个针对某航空器油箱的焊接实例,对所提出的优化模型及算法的实用性进行了验证,结果表明优化参数可在保证加工质量的前提下有效地节省时间60.41%~69.05%,节省电能34.88%~46.30%。     

Acousto-optic spectrum analyzer techniques for monitoring CW

The issues associated with processing the outputs of an integrating acoustooptical spectrum analyzer (AOSA) to detect and identify the frequency and power of continuous wave (CW) signals are considered. The performance of the optimum detection strategy is presented, along with the Cramer-Rao bound on the performance of estimators of the frequency, and the performance of a simple peak-based frequency estimator. The performance of the maximum likelihood (ML) estimator of the power level is also presented. The results provide the behavior of the system as a function of the product of the aperture time and photodetector spacing amongst other parameters     

新一代飞机任务系统概念与构架

新一代飞机是面向全球战略的空中力量组织,其任务系统是利用全球、全域和全空间能力组织,构建全球、全域和全空间警戒、到达和对抗的优势,实现面向全球的战略目标。从全球战略、战术和任务组织思想的角度,论述了新一代飞机任务系统战略需求和存在的挑战,描述了任务系统的"蝴蝶效应"及其形成过程等基本概念,构建了基于战略、战术、任务构架组织的战略云、战术云和任务云的系统框架组织,论述了相应的复杂系统、不确定性和智能化处理思路。     

Network-Enabled Missile Deflection: Games and Correlation Equilibrium

The problem of deploying countermeasures (CM) against antiship missiles is investigated from a network centric perspective in which multiple ships coordinate to defend against a known missile threat. Using the paradigm of network enabled operations (NEOPS), the problem is formulated as a transient stochastic game with communication where the appropriate strategy takes the form of an optimal stationary correlated equilibrium. Under this strategy, ships cooperate through real-time communication to satisfy both local and collective interests. The use of communication results in a performance improvement over the noncommunicating, Nash equilibrium scenario. This framework allows us to develop a theoretical foundation for NEOPS and captures the trade-off between information exchange and performance, while generalizing the standard Nash equilibrium solution for the missile deflection game given in [1], The NEOPS equilibrium strategy is characterized as the solution to an optimization problem with linear objective and bilinear constraints, which can be solved calculating successive improvements starting from an initial noncooperative (Nash) solution. The communication overhead required to implement this strategy is associated with the mutual information between individual action probability distributions at equilibrium. Numerical results illustrate the trade-off between communication and performance.     

SiCp/Al复合材料加工损伤及刀具优选研究进展

SiC_p/Al复合材料中增强相SiC颗粒的存在降低了该材料的加工性能,使得其切削加工时产生一系列加工损伤。本文综述了SiC_p/Al复合材料的加工缺陷类型、缺陷形成机理、缺陷控制策略和切削刀具的磨损机理与优选策略,并对今后SiC_p/Al复合材料加工损伤研究进行了展望。     

Galileo AltBOC signal multiresolution acquisition strategy

Herein, some critical aspects related to the acquisition of the future Galileo signals are discussed. In particular, the Alternative Binary Offset Carrier (AItBOC) modulation that will be used by the Galileo satellites to broadcast navigation signals on the E5 band is considered, addressing acquisition issues only partially analyzed in previous works. The implementation of an acquisition section for the AltBOC signals is not straightforward, since several different receiver architectures can be used and remarkable differences are required with respect to the conventional signal processing used in GPS receivers. The main problems that must be handled (risk of false lock, resolution of the search space, and computational burden) are outlined in the following. An innovative technique, called multiresolution acquisition and tailored to the AltBOC signals, is then proposed as an effective solution to previous problems. As demonstrated by means of simulations, this novel strategy can be successfully used in coherent dual-band AltBOC receiver architectures with a feasible implementation complexity and it leads to remarkable advantages in terms of acquisition time.     

Trajectory deviations in airborne SAR: analysis and compensation

This paper concerns the analysis and compensation of trajectory deviations in airborne synthetic aperture radar (SAR) systems. Analysis of the received data spectrum is carried out with respect to the system geometry in the presence of linear, sinusoidal, and general aircraft displacements. This shows that trajectory deviations generally produce spectral replicas along the azimuth frequency that strongly impair the quality of the focused image. Based on the derived model, we explain the rationale of the motion compensation (MOCO) strategy that must be applied at the SAR processing stage in order to limit the resolution loss. To this end aberration terms are separated into range space invariant and variant components. The former can be accounted for either in a preprocessing step or efficiently at range compression stage. The latter needs a prior accommodation of range migration effect. We design the procedure for efficient inclusion of the MOCO within a high precision scaled FT based SAR processing algorithm. Finally, we present results on simulated data aimed at validating the whole analysis and the proposed procedure     

Performance limits of sensor-scheduling strategies in electronic support

The case is considered in which a frequency-agile receiver (FAR) for electronic support (ES) attempts to intercept radar emissions over a wide search bandwidth. It was recently shown [1,2] that a random strategy exists in which the expected intercept time can be made arbitrarily close to linear as a function of the scan period of the radar. Can a deterministic strategy be devised in which a similar linear relationship exists for the maximum intercept time? By applying the celebrated arithmetic results of van der Waerden [3] and Szemeredi [4], we show that no such strategy is possible.     

国外企业战略更新:主题述评与研究展望

企业的战略更新是企业应对内外部环境变化,通过改变其战略意图和行为来改变其路径依赖和谋求竞争优势的过程,对于企业塑造其战略灵敏性、环境适应性以及克服企业危机等方面有重要意义.基于国内战略更新研究匮乏的现状,以国外战略更新相关研究成果为切入点并从战略更新前因、过程及结果三个方面进行整合分析.在提出了时下战略更新研究体系及框...     

Security applications of computer vision

In an age which bears witness to a proliferation of Closed Circuit Television (CCTV) cameras for security and surveillance monitoring, the use of image processing and computer vision techniques which were provided as top end bespoke solutions can now be realised using desktop PC processing. Commercial Video Motion Detection (VMD) and Intelligent Scene Monitoring (ISM) systems are becoming increasingly sophisticated, aided, in no small way, by a technology transfer from previously exclusively military research sectors. Image processing is traditionally concerned with pre-processing operations such as Fourier filtering, edge detection and morphological operations. Computer vision extends the image processing paradigm to include understanding of scene content, tracking and object classification. Examples of computer vision applications include Automatic Number Plate Recognition (ANPR), people and vehicle tracking, crowd analysis and model based vision. Often image processing and computer vision techniques are developed with highly specific applications in mind and the goal of a more global understanding computer vision system remains, at least for now, outside the bounds of present technology. This paper will review some of the most recent developments in computer vision and image processing for challenging outdoor perimeter security applications. It also describes the efforts of development teams to integrate some of these advanced ideas into coherent prototype development systems     

Intrinsic evolution of safe control strategies for autonomous spacecraft

Autonomous space vehicles need adaptive control strategies that can accommodate unanticipated environmental conditions. Although it is not difficult to construct alternative control strategies, a proper evaluation frequently can only be done by actually trying them out in the real physical environment. It therefore becomes imperative that any candidate control strategy be deemed safe - i.e., it does not damage any systems - prior to being tested online. How to do this has been a challenging problem. We propose a solution to this problem. Our approach uses an evolutionary algorithm (EA) to intrinsically evolve new control strategies. All candidate strategies are checked for safety using formal methods. More specifically, an EA evolves a series of finite state machines (FSMs), each of which encodes a unique control strategy. Model checking guarantees whether all safety properties are satisfied in the strategy. A numerical example is included to illustrate our approach.