基于CppUnit的虚拟试验单元测试研究

虚拟试验是通过大量平台软件验证实物试验的可行性,达到“以实验虚 以虚辅实 以虚预实”的目的。这对平台软件的稳健性具有较高的要求,软件测试是提高软件产品质量的重要手段,而其中的单元测试是对软件模块的功能测试。CppUnit主要用于实现对软件的单元测试,本文基于CppUnit提出了一种应用于虚拟试验平台软件的单元测试方法,实现了对平台软件功能的单元测试,平台使用者在软件开发阶段不仅能较好地验证软件的稳健性,而且能提高虚拟试验验证的效率,为实物试验提供参考依据。     

一种用于分布式控制的光纤通信协议设计与仿真

针对航天飞行控制系统特点,对比了光纤通道协议的三种拓扑结构的应用,对实际特定应用中功能与需求结合不紧密的方面进行研究,提出了一种适用于航天领域分布式控制的光纤通信协议;详细描述了协议的功能框架、拓扑结构和数据格式,基于FPGA搭建了通信协议的实现平台,着重描述了工作流程和状态机设计,最后对协议设计进行了多节点通信仿真;结果表明通信协议能够满足分布式控制需求;对于未来光纤总线在航天领域的应用具有推广意义。     

面向航天型号软件缺陷预测的属性选择方法

针对当前航天型号软件模块故障预测中度量属性过多而影响分类模型效率、准确率和数据收集困难的问题,以NASA公布的MDP数据集为基础,设计了基于Logistic回归模型的属性选择算法;通过该算法在6个数据集上的应用选择了对航天型号软件质量影响较大的4个属性,并将其在12个软件中进行验证,说明了该算法的有效性,选择的4个度量属性可为当前航天型号软件的度量提供参考和依据。     

舰船嵌入式软件测试用例自动驱动研究

针对舰船嵌入式软件手动测试的弊端,首先从业务逻辑、接口类型等方面总结了舰船嵌入式软件的特点,从测试用例的建模、形式化转换以及用例的解析3个方面提出了测试用例自动驱动方案,在此基础上,根据舰船嵌入式软件的业务逻辑,研究了测试用例建模方法,包括测试用例数据模型、行为模型和测试用例模型特性,给出了测试用例自动驱动方法,并且以上述方法为基础对测试用例自动驱动平台进行了设计,给出了平台硬件组成和软件设计方案;最后,利用测试用例驱动平台对某软件进行了测试应用验证,验证结果表明利用测试用例驱动平台可以显著提高测试效率。     

基于FPGA和SSPC的智能配电系统设计与实现

航天及航空领域智能配电技术发展迅速。配电系统是航天及航空飞行器的重要分系统,其性能的优劣直接影响到飞行任务的成败,为了提高配电系统的可靠性和灵活性,提出了基于FPGA和SSPC的智能配电系统设计,从航天及航空飞行器智能配电技术的发展现状出发,具体阐述了该系统总体方案的设计思路及关键技术,同时分析了采用FPGA、SSPC和总线通信带来的控制灵活、易于实现故障隔离和系统重构、可靠性高以及系统重量轻等诸多优点。该系统已开展了相关的试验验证,试验结果表明该系统稳定可靠,具有广泛的应用前景。     

基于ARINC629的层次化验证平台设计

结合约束随机、覆盖率驱动及断言等多种验证方法,对层次化验证平台的搭建方法进行了研究;以对ARINC629航空数据总线接口控制器的验证过程为例,介绍了基于System Verilog的层次化验证平台的搭建过程及其使用方法;根据验证后覆盖率报告,证明各项功能均已达到其设计需求,且实现率为100%;验证结果表明该平台和传统验证方法相比极大地提高了验证效率,平台的搭建方法和结构具有一定的通用性,更改其数据生成模块即可用于其他类似设计的验证。     

IOTEST在某型模拟对抗终端嵌入式软件测试中的应用

由于嵌入式系统对功能和性能的高要求,对嵌入式软件进行测试存在一定难度。嵌入式系统通过各种不同类型的接口与外界实现交互,故而对嵌入式系统的接口进行测试,是保证嵌入式软件质量的重要途径。以某型模拟对抗终端嵌入式软件为例,根据该型终端的特点,对基于IOTEST实现嵌入式软件测试的自动化进行研究。依照测试需求分析、测试环境搭建、测试建模、变量配置、测试脚本编写、测试执行的测试步骤和方法,通过测试实现过程详细说明了IOTEST在嵌入式软件测试中的应用。测试结果表明,IOTEST能够对嵌入式系统接口的正确性、实时性和可靠性进行有效地测试,该工具在测试过程中具备良好的实用性和通用性。在嵌入式软件的测试过程中合理使用IOTEST,可以有效提高测试效率,保证软件质量。     

FPGA中信号可靠性设计的方法研究

对FPGA程序设计中存在的信号抖动、相位差异以及在模块继承时不同时钟域引起的软件异常等可靠性设计问题,将目前常用的信号抖动抑制及判断方法进行了分析总结,提出了几种新的FPGA内部的信号处理方法;通过实验验证,这些方法对不同脉冲宽度、不同突发频率的随机干扰,能够进行有效抑制;通过合理降频、例化原语等方法优化软件设计,提高了FPGA输出信号的完整性和可靠性;在航天、航空和工业控制领域中,有效地解决了软件系统的可靠性问题,为建立可靠性高、运行稳定的软件系统创造了条件。     

基于增量光栅尺的纵横转换图像细分算法实现

针对现有光栅测量方法不能兼顾高速与高精度的问题,为适应电子制造装备高速运动和高精密定位的位移反馈要求,提出基于增量式光栅尺的纵横转换细分测量原理和相应的图像快速处理算法。为了提高光栅图像采集处理速度,搭建基于FPGA的硬件测试平台,先将采集到的图像进行滤波和二值化处理,然后对图像先进行纵横坐标相加,求取像素点最小值得到交点位移值。实验结果表明:应用纵横转换算法并搭载FPGA测试系统,能够达到0.029 μm的分辨率,精度达到0.3 μm。     

云计算在航天测试领域的研究与应用

为满足航天测试领域日益增长的数据处理需求,利用云计算技术提高航天测试领域的数据处理性能和数据可靠性,数据安全性,主要从三个方面对云计算技术与航天测试领域结合进行了研究,首先建立以Hadoop为基础架构的云计算平台,设计新的测试数据传输方案,并以Hadoop冗余备份机制为基础,提高数据可靠性;其次,对云计算平台的数据处理模块进行了研究,并与航天测试领域的数据比对工作相结合;最后,为云计算平台设计了安全性更高的身份认证和加密模块.通过与原有航天测试工作对比分析可以看出,云计算对航天测试领域数据处理速度的提升是巨大的,安全模块也有效的对数据进行了保护,适应了航天测试领域对安全方面的高要求,将云计算应用于航天测试领域具有极大的潜力和广阔的前景。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.     

Fiber Modal Index Measurements Based on Fiber Gratings

A novel method based on fiber gratings for measuring the effective indices of fiber modes is proposed. The effective index difference between the core mode and a cladding mode was obtained by analyzing the interference fringe of a pair of cascaded long-period fiber gratings. In order to extract the core mode index from the measured index difference, an index matching oil immersion method is proposed. By analyzing the interaction between the cladding mode and the oil applied on the cladding surface, the mode order and the effective index of the involved cladding mode might be calculated. Experimental results about the interference fringe shifts induced by the oil index and the oil-applied length are also presented.     

Optical Pulse Compression Schemes That Use Nonlinear Bragg Gratings

Nonlinear optical pulse compression of picosecond pulses typically requires long lengths of optical fiber and multiple components. Periodic structures, such as fiber Bragg gratings, are highly dispersive at wavelengths outside of the photonic bandgap. This implies that such gratings can be used as very short all-fiber compressors. In this paper a number of such compression schemes are reviewed involving uniform and nonuniform fiber Bragg gratings, relying on both soliton and nonsoliton compression principles. Experimental results supporting the corresponding underlying theory are also presented. Finally, an extension of one of the compression schemes is shown, which allows the generation of adjustable high-repetition rate soliton trains.