基于代码覆盖率的回归测试用例缩减

提出一种基于代码覆盖率的测试用例推荐的算法,可以在保证代码覆盖率的情况下,挑选出较小的用例子集,大大减少回归测试运行时间,遗传算法具有适应性好,效果佳的特点,采用一种改进的遗传算法实现用例缩减功能,用贪心算法生成初始种群,用测试覆盖率和测试时间成本构造适应度函数,通过海明距离来计算变异与交叉算子,最后给出实验结果,实验表明,改进的遗传算法能有效的减少测试用例,缩短测试运行时间。     

基于模糊数学的测试用例优化技术研究

为了缩短软件测试周期,测试用例的生成是关键.在模糊综合评判数学模型和马尔可夫使用链模型的基础上,提出了基于模糊数学的测试用例优化的方法.通过实例证明了这一技术的实用性和有效性.     

基于概率论的测试用例优化技术研究

软件可靠性测试是软件工程中的一个新的研究领域.为了缩短软件测试周期,测试用例的生成是关键.基于马尔可夫链模型,提出了一种测试用例优化技术,该理论采用适应度比例的概率方法进行优化.通过例子证明.该方法在产生均匀、优化的测试用例方面是有效的.     

基于遗传蚁群算法的测试用例集约简

为提高软件测试效率,节省回归测试成本,本文提出了一种新的约简测试用例集的算法.该算法是遗传算法和蚁群算法两种算法的结合,首先利用遗传算法的快速随机全局搜索能力,生成蚁群算法的初始信息素,然后利用蚁群算法的正反馈性,快速得到约简测试用例集的近似最优解.最后通过仿真实验验证了该算法的有效性.     

一种基于DARTS设计的嵌入式软件测试用例模型

嵌入式系统是目前计算机研究领域的一个热点，嵌入式软件的特点使其设计方法发生了变化，软件测试是保证嵌入式产品质量的关键，研究新设计方法下的新测试方法是非常必要的。本文分析了嵌入式软件的特点，对嵌入式软件测试的方法和问题进行了讨论，根据DARTS设计方法和基于规约说明的测试方法，提出了一种基于任务划分的实时嵌入式软件的测试用例生成模型。     

基于形态学膨胀和差分缩减的DCT域嵌入式图像压缩算法

提出了一种基于形态学膨胀操作和差分缩减的DCT域图像编码方法,该方法根据块内DCT系数的聚集特性和块间DCT系数的相似性,使用形态学膨胀算子优化DCT重要系数的编码,并对重要性检测和符号编码精心设计了上下文自适应算术模型,有效去除了块内、块间DCT的统计相关性;使用差分缩减方式对各DCT系数聚类簇的起始位置和稀疏系数进行编码,提高对不重要DCT系数的编码效率;算法还结合预处理和后处理滤波器,进一步提高编码效率的同时可有效抑制解码图像的方块效应.编码器基于位平面实现,码流具有渐进性.实验结果表明本文算法的编码性能普遍优于目前主流的图像编码器,例如在0.25 bpp下,Lena和Barbara图像的峰值信噪比分别较JPEG2000提高0.4dB和1.7dB.     

基于数据缩减的分频段小波模态参数快速识别

针对利用小波进行模态参数识别效率较低的问题,提出了一种基于数据缩减的分频段小波模态参数快速识别算法。利用奇异值分解对协方差信号在保留数据信息量的情况下进行缩减以减少参与计算的数据量,对正功率谱密度矩阵的奇异值分解确定识别系统的模态阶数及相应的频率范围,利用小波变换对缩减后的数据进行各阶模态逐频段识别。相比原始算法,文中方法减少了小波分析的数据量并避免了一些无用频带的小波分解从而减少计算量。通过对一个3阶线性时不变系统以及一个大桥模型的参数识别验证了文中方法在保持识别精度的情况下大幅度地提升了计算效率。     

基于复杂网络社团聚类的复合故障特征分离诊断方法

针对复合故障多种故障特征相互叠加彼此干扰,给全面准确诊断带来困难,提出了基于复杂网络社团聚类的复合故障特征分离诊断方法。该方法首先应用EMD将复合故障信号分解为若干个IMF分量,由于不同单一故障的特征会在不同频段得以体现,提取每个IMF分量的特征量,建立故障数据网络模型;然后将每个IMF分量视为网络中的社团,根据复杂网络社团结构的特性,进行同类社团合并,合并所得每个社团与单一故障相对应,最后对合并的信号进行分析,实现复合故障特征分离。本文以转子不平衡和轴承内圈、轴承内圈和滚动体复合故障特征分离与诊断为例,验证了该方法的可行性。     

基于MOABCO的多目标测试用例优先级排序

为了提高回归测试的效率,提出了一种基于多目标人工蜂群优化(Multi-Objective Artificial Bee Colony Optimization, MOABCO)算法的多目标测试用例优先级排序(Multi-Objective Test Case Prioritization, MOTCP)方法.针对标准多目标人工蜂群(Multi-Objective Artificial Bee Colony, MOABC)算法容易陷入局部最优解的问题,将差分变异策略融入到新蜜源更新阶段,且基于信息熵改进新蜜源选择方法,以避免算法陷入局部最优并增强了全局搜索能力;然后,将代码覆盖率和测试用例有效执行时间作为优化目标,并用MOABCO算法求Pareto最优解集,以解决MOTCP问题.实验结果表明, MOABCO算法求得的Pareto最优解集在逼近性和分布均匀性上均优于MOABC算法;在解决MOTCP问题上,相对于NSGA-II算法具有更高的收敛速度和更高的缺陷检测率.     

基于结点位移插值的约束子结构界面自由度缩减方法

基于结点位移插值原理,建立了约束模态子结构界面自由度的缩减方法,形成了约束子结构模态综合法的二次坐标变换矩阵.通过第二次坐标变换可有效地缩减计算系统的广义自由度,提高计算效率.算例表明,这种缩减方法是合理有效的.该文还讨论了插值基点的选择方式对计算精度的影响,计算结果表明,当选择的插值基点在界面上均匀分布时,计算精度最好.最后,对比了插值域的形状对计算精度的影响,计算结果表明,矩形插值域的计算精度要好于三角形插值域.     

Model reduction for LPV systems based on approximate modal decomposition

The paper presents a novel model order reduction technique for large‐scale linear parameter‐varying (LPV) systems. The approach is based on decoupling the original dynamics into smaller dimensional LPV subsystems that can be independently reduced by parameter‐varying reduction methods. The decomposition starts with the construction of a modal transformation that separates the modal subsystems. Hierarchical clustering is applied then to collect the dynamically similar modal subsystems into larger groups. The resulting parameter‐varying subsystems are then independently reduced. This approach substantially differs from most of the previously proposed LPV model reduction techniques, since it performs manipulations on the LPV model itself, instead of on a set of linear time‐invariant models defined at fixed scheduling parameter values. Therefore, the interpolation, which is often a challenging part in reduction techniques, is inherently solved. The applicability of the developed algorithm is thoroughly investigated and demonstrated by numerical case studies.     

Robust profile alignment based on penalised-spline smoothing

In quality engineering practice, profiles that are used for quality monitoring or evaluation are sometimes unaligned due to engineering constraints. In such cases, profiles have to be registered (aligned) through shifting, time warping or coordinate alignment such that samples are comparable and easy to handle. Among the different registration algorithms, time warping, or alignment of profiles with unequal lengths, is a challenging task. In quality engineering, a typical phenomenon observed in profile alignment is that neighbours of an aligned pair have a high possibility of being similar, which means that a large jump in a warping path is less likely. In this article, a penalised-spline smoothing method is proposed for profile alignment to handle this problem. The newly proposed nonparametric alignment strategy attempts to capture the smoothness and spatially correlated features of warping shifts, and is proven more robust than existing algorithms. A dynamic programming algorithm is developed to obtain the optimal path. Both simulation studies and a real example demonstrate the effectiveness of the proposed method.     

Process capability index for Poisson regression profile based on the Spmk index

In many process control applications, the quality of a process or a product can be characterized by a functional relationship between a response variable and one or more explanatory variables which is typically referred to as a profile. Such profiles can be expressed by a linear or a non-linear model. On the other hand, for an in-control process, capability indices are used for process quality improvement. In this article, we propose a method to measure the process capability when the quality of the process is characterized by a Poisson regression profile. The performance of the proposed index is evaluated through simulations studies. Two real data examples illustrate this method.     

基于椭圆线轮廓度误差评定的椭圆提取方法

简要介绍了目标测头视觉坐标测量系统,分析了测量系统成像目标的图像特征。在此基础上,提出了一种识别和提取CCD图像中目标椭圆的新方法。该方法对CCD图像中的每一个封闭轮廓进行椭圆拟合,根据评价椭圆形状误差的线轮廓度大小来判定该轮廓是否为目标椭圆轮廓。实际检测结果表明,该算法原理正确,易于编程实现,能有效剔除噪音图像,准确提取目标椭圆,具有广泛的实用性。     

Study on the void reduction behaviour of porous asphalt pavement based on discrete element method

The objective of this study was to analyse the void reduction behaviour of porous asphalt mixture under load. A three-dimensional discrete element model of porous asphalt mixture based on aggregate gradation and void gradation was built in PFC3D software. The parameter of the model was obtained from creep test. The rutting test was simulated using this discrete element model. And a new method was developed to obtain and analyse the void structure in discrete element model. The simulation results were compared with one of the laboratory test. The comparative analysis indicates that, the discrete element method can be used to simulate the creep response and void reduction behaviour of porous asphalt mixture. Further research shows that porosity, effective porosity, number of connected components and section pores have a good correlation with strain of porous asphalt mixture. With the increase in strain, the proportion of section pores with diameter less than 2 mm increases. In the initial stage of loading, the void reduction is the main reason for rut increment of porous asphalt mixture. In the later stage, the void structure is almost incompressible; the lateral deformation of mixture becomes the domination factor.     

真空硅浴熔融还原白云石炼镁的实验研究

通过往煅烧白云石中添加适量的Al2O3和SiO2,使其在1500～1600℃之间形成熔融炉渣,并在真空下采用硅铁还原液态渣中的MgO。研究了造渣剂对MgO还原率的影响,结果表明,在能够获得熔融炉渣的情况下,增大Al2O3/SiO2比能够极大地提高渣中MgO的还原率,理想的炉渣成分为32.0%CaO-23.0%MgO-35.0%Al2O3-10%SiO2。同时,对该炉渣进行了正交实验,通过分析得出影响MgO还原率因素的顺序依次是:反应温度、还原剂硅铁添加量、反应时间、催化剂CaF2添加量。在熔融还原工艺参数为:反应温度1600℃,还原剂硅铁添加量n(Si)/n(2MgO)=1.2,反应2h,催化剂CaF2添加量3%条件下,渣中的MgO还原率高达97.3%。     

Sequential sampling designs based on space reduction

In the field of engineering design and optimization, metamodels are widely used to replace expensive simulation models in order to reduce computing costs. To improve the accuracy of metamodels effectively and efficiently, sequential sampling designs have been developed. In this article, a sequential sampling design using the Monte Carlo method and space reduction strategy (MCSR) is implemented and discussed in detail. The space reduction strategy not only maintains good sampling properties but also improves the efficiency of the sampling process. Furthermore, a local boundary search (LBS) algorithm is proposed to efficiently improve the performance of MCSR, which is called LBS-MCSR. Comparative results with several sequential sampling approaches from low to high dimensions indicate that the space reduction strategy generates samples with better sampling properties (and thus better metamodel accuracy) in less computing time.     

基于数码相机特性文件的色彩校正和色彩管理研究

阐述了颜色特性文件的作用,分析了数码相机颜色特性文件的制作过程和使用原理,并对使用数码相机颜色特性文件进行色彩校正和色彩管理进行了研究,有效的实现了数码相机的色彩还原和保证了颜色复制过程中的一致性.