基于先验知识的微型零件检测中异物伪信息的剔除

微型零件视觉检测中,视场内灰尘、发屑等异物的存在会改变所提取的目标轮廓。为避免异物对测量带来的影响,提出了一种基于先验知识思想的异物伪信息剔除方法。首先对带有异物的零件图像进行角点检测;接着统计得出标准零件的角点分布特征作为先验知识;最后由标准零件角点特征得出异物伪信息判定条件,据此剔除异物伪信息。通过在实际工程项目中的成功应用,以三幅典型带异物微型零件图像的处理过程为例,证明了算法在保证测量精度的同时有效剔除了图像中的异物伪信息。     

基于区域权函数理论的多电极电磁流量计电极设计

基于Shercliff权函数提出区域权函数概念,设计多电极电磁流量计,通过测量管道截面不同位置的弦端电压,计算各区域的轴向平均速度,实现速度分布与体积流量的测量。着重研究了流量计电极设计,选取不锈钢平头方案的多电极电磁流量计,对于阀门下游的非轴对称单相流体积流量测量精度高于±1.0%,倾斜管固—液两相流实验证明:该设计对于两相流非轴对称的速度分布测量具备可靠性。     

基于Maven的J2EE后台管理系统代码生成器

后台管理系统功能和模式相对固定,为了降低软件开发人员的重复工作量,缩短项目的开发周期,应用基于模板技术的代码生成原理,设计一款基于Maven的后台管理系统代码生成器,完成从业务模型到后台管理系统的代码生成;从业务文件定义、业务文件解析到模板合成阐述本代码生成器的内部结构。     

X-Ray, Micro-Raman, Optical Absorption/Emission Studies of ErNbO4 Grown by Vapor Transport Equilibration

Vapor transport equilibration (VTE) treatments were performed on a Y-cut bulk Er (1.6 mol%)-doped congruent LiNbO₃ crystal and an X-cut pure congruent crystal, on one surface of which a 40 nm-thick film of erbium metal was coated before the VTE treatment. Scanning electron microscope, powder or single-crystal X-ray diffraction (XRD), polarized infrared absorption/emission of Er³⁺ as well as micro-Raman spectroscopy were used to study the two VTE crystals. The results are discussed in comparison with a corresponding as-grown bulk Er-doped crystal, calcined ErNbO₄ powder, and a locally Er-doped congruent LiNbO₃ crystal prepared by using the standard Er-diffusion technique. The experimental results show that the VTE treatment induces the formation of micrometer-sized ErNbO₄ precipitates with the crystallographic morphology of a flat polyhedron not only on the surfaces of both crystals but also in the bulk of the homogeneously Er-doped one. The optical absorption and emission studies show that the formation of the precipitates results in substantial spectral changes in both the 0.98 and 1.5 μm regions. The micro-Raman studies allow to resolve four additional Raman peaks around 800 cm⁻¹ in the E(TO) spectra of the two VTE crystals. These additional Raman peaks are associated with the characteristic vibrations with respect to the NbO₄³⁻ group. Characteristic XRD, optical absorption, and emission and Raman peaks for identifying the ErNbO₄ phase are proposed. Finally, the formation mechanism and light-scattering effect of the precipitates are discussed.     

Rate control of hierarchical B prediction structure for multi-view video coding

Rate control plays an important role in regulating bit streams in video coding. In order to obtain good coding performance, the hierarchical B prediction structure has been adopted in Multi-view Video Coding (MVC). However, the conventional rate control scheme is not efficient in the hierarchical B prediction structure. In this paper, we propose a rate control algorithm to address this problem. First, the accurate estimation of Mean Absolute Distortion (MAD) of the current frame is desired for both quantization parameter (QP) selection and Rate Distortion Optimization (RDO). Considering the hierarchical B structure, a bi-directional MAD prediction model is proposed to predict the MAD of the current frame by using the actual MADs of the encoded frames in the lower Temporal Layers (TLs). Second, the number of header bits has a close relationship with the TLs in the hierarchical B prediction structure. Therefore, we propose an enhanced prediction method in which a proportional relationship of the header bits is introduced if the frames are located in different TLs. Experimental results show that our proposed algorithm can achieve both accurate target bit rate and good coding performance.     

全生命周期软件过程风险管理模型研究

首先从软件过程的角度重新定义了过程风险的基本概念;然后结合CMMI和软件的生命周期分别从软件过程、生命周期和风险管理构建了三维结构的软件项目风险管理模型,提出了基于CMMI的全生命周期的过程风险策划、识别、评估和监控全过程模型;最后建立了软件研制风险管理系统,该系统在实际应用中取得了较好的效果。     

基于重力坝三维设计的CAD动态交互系统开发

为了在可研阶段合理、快速地制定重力坝设计方案,减少设计周期和成本,采用极限状态设计的方法,利用VB 6.0可视化编程工具开发出了一套能够与CAD动态交互的重力坝三维设计系统。该系统通过对Auto-CAD的二次开发实现了重力坝的三维参数化建模,并对所建三维模型进行结构计算,将设计与计算紧密结合,通过动态交互简化了大量复杂数据的计算,达到精确、快速完成断面设计的目的。经实践检验证明,该系统大大提高了断面设计效率,实用性强,对可研阶段的方案比选具有重大意义。     

资源受限项目调度问题的改进文化微粒群算法求解

为了克服标准微粒群算法在求解资源受限项目调度问题上存在的早熟现象,提出一种改进的文化微粒群算法。该算法框架基于微粒群算法的主群体空间和文化算法的知识空间,两种空间具有各自的群体并可独立并行演化,形成双演化双促进机制,提高了算法的全局搜索能力和运行效率。同时为了避免文化算法知识空间自我演化限制,引入遗传算法的演化机制来改进知识空间的演化操作。通过具体的算例比较,验证了提出的改进文化微粒群算法在求解资源受限项目问题时的有效性。     

Synthesis and Morphology of TiO2 Nanotube Arrays by Anodic Oxidation Using Modified Glycerol-Based Electrolytes

Titanium dioxide (TiO₂) nanotube arrays were prepared by electrochemical anodization of titanium sheets in the glycerol 176 mL/H₂O 44 mL/NH₄F 0.5 wt% electrolytes modified with H₂SO₄ and NaAc addition. The surface morphologies, average inner diameter, and the length of the nanotube arrays changed with the solution pH in the range from 5.6 to 4.0 by adding H₂SO₄. A uniform surface morphology of the nanotubes with average inner diameter of ∼80 nm and a length of ∼1000 nm was obtained when the solution pH was 5.0. The growth rates of the nanotubes were remarkably enhanced by NaAc addition in the range of 0.04–0.14 M . With NaAc addition of 0.10 M , the length of the nanotube arrays reached 4.16 μm after an 8-h anodization, increasing 3.23 μm compared with no NaAc addition. The relationship between solution pH and growth of TiO₂ nanotubes was analyzed by current–time curves, solution electrical conductivities, and scanning electron microscopy (SEM), and the role of NaAc was also discussed based on SEM and solution electrical conductivities.