融合特征光流与角点特征的图像特征匹配算法研究

图像特征匹配是视觉里程计的重要环节,针对视觉图像序列特征点匹配中存在的匹配精度低问题,提出一种融合金字塔特征光流与角点特征的精确快速图像特征匹配算法。算法首先利用ORB(二进制定向简单描述符)算法快速提取图像特征点,然后融合金字塔Lucas-Kanade特征光流的追踪特性,使用局部特征窗口计算图像特征点位移矢量。接着针对图像特征的匹配对齐问题以及特征丢失问题,算法采用K最近邻半径搜索作为特征滤波器移除混淆的匹配,最后使用RANSAC(Random Sample Consensus)算法剔除冗余误匹配点对,提高匹配率。通过多组实验数据对比,该算法的图像特征匹配率可达到98%。对比传统的ORB特征匹配算法,该算法在实时性和图像特征匹配精度上均有显著提高。     

基子光谱差分吸收技术的农药残留检测研究

针对国内主要食品中广泛存在的农药残留带来的食品安全问题,研究一种方便快捷且成本适宜的检测技术,具有重要的意义。目前,已有相关实验将光谱吸收技术用于食品农药残留检测,但是,对于定量检测及测量精度方面该实验还存在一些不足。本文基于差分吸收技术,采用荷兰Avantes公司的微型光纤光谱仪以及分光光度计,进行了相关实验,实现了对敌敌畏水剂农药的定量测量,从而对基于光谱吸收技术的农药残留检测技术进行了完善,使其更加适合实际应用。     

First principle study of spintronic properties for double perovskites Ba2XMoO6 with X=V,Cr and Mn

Cubic double perovskites Ba₂XMoO₆ (X=V, Cr and Mn) compounds are studied using the full potential linearized augmented plane wave (FP-LAPW) method within the frame work of density functional theory (DFT). The structural, electronic and magnetic properties are calculated by using the Generalized Gradient Approximation (GGA), GGA+U and modified Becke–Johnson mBJ-GGA. Density of States and band structure results reveal a similar half-metallic ferromagnetic ground state for Ba₂CrMoO₆. Whereas, a metallic ferromagnetic character is predicted for Ba₂VMoO₆ and a matching metallic ferromagnetic ground state is obtained for Ba₂MnMoO₆. The mBJ calculations yield a better energy-gap than the GGA and GGA+U methods.     

Band gap engineering by substitution of S by Se in nanostructured CdS1−xSex thin films grown by soft chemical route for photosensor application

Ternary alloys of CdS_1−xSe_x (x=0, x=0.2, x=0.4, x=0.6, x=0.8, x=1) thin films were prepared on to glass substrates by a simple and economical soft chemical route (chemical bath deposition) at 50° to 80 °C in air. The as-grown films were characterized by optical and electrical measurement systems, X-ray diffraction (XRD), Energy dispersive X-ray analysis (EDAX) and SEM (scanning electron microscopy). The optical study reveals shift in the absorption edge towards the higher wavelengths, i.e. the band gap decreases as a function of ‘x’ (quantity of selenium in the bath). I–V measurement of CdS (resulted when x=0), CdS_1−xSe_x (x=0.2, x=0.4, x=0.6, x=0.8) and CdSe (resulted when x=1) thin films under dark and illumination conditions (60 W) were measured. Increase in photoconductivity is observed, suggesting its applicability in photosensor devices. Electrical resistivity shows semiconducting behavior and activation energy decreases. The XRD patterns reveals that deposited thin films have hexagonal mixed structure. EDAX confirmed the compositional parameters. SEM images showed uniform deposition of the material over the entire glass substrate.     

新型高效低噪叶片在主通风机中的应用

通过分析风机叶片噪声的类型,研究风机叶片产生空气动力性噪声的机理,采用三元流理论设计出低噪主通风机叶型,并利用模型机试验测试装机效果,筛选出分别符合精密铸造工艺和铆焊工艺的低噪主通风机叶型。     

Measuring contradiction on A-IFS defined in finite universes

The work outlined here aims to build and examine contradiction measures on Atanassov intuitionistic fuzzy sets (A-IFS) that are defined in this particular case in finite universes. The axiomatic definition of contradiction measure in the A-IFS framework was given in [7]. A number of axioms formalizing the concept of continuity for the above measures were also given. In this paper, Section 1, which briefly discusses the preliminaries required to develop the work, is followed by a section analysing how the restriction of the universe of discourse to a finite set influences the continuity axioms. The following three sections look at three types of specific contradiction measures. In Section 3, continuous t-norms and fuzzy negations are used to construct a large family of measures. These measures satisfy different types of continuity, which are examined at length. Then, Sections 4 Contradiction measures from geometrical methods, 5 Contradiction measures in reference to the region of non- take up other families introduced in [8], [10], [9], proving that their behaviour with respect to continuity is better than it was in the earlier articles because the universes considered here are finite.     

Nature of intrinsic and impure luminescence of MAlP2O7 crystals

The results of the photoluminescence (PL) investigation of pure and chromium-doped MAlP₂O₇ (M = Na, K, Cs) compounds are presented. The spectra of the intrinsic luminescence of MAlP₂O₇ crystals consist of a separated UV band at a peak position near 330 nm and a complex wide band which covers the region of visible light up to 750 nm at excitation by VUV synchrotron radiation. The “red” band in 600–1000 nm diapason appears in the PL spectra of crystals doped with chromium ions. The effect of the temperature on the structure, the peak positions and intensities of the luminescence bands was studied. An assumption about the nature of the intrinsic PL was made. The “red” luminescence was considered as a result of the ⁴Т₂ → ⁴А₂ radiation transitions in the impurity Cr³⁺ ions located in the intermediate crystal field.     

Modeling the dynamic effects of ice shedding on spacer dampers

Effects of ice-shedding-induced cable vibration on spacer dampers are studied by applying a dynamic model. The model is based on the authors' recent development, which is improved here by applying spacer properties obtained experimentally. The model simulates cable vibration and bundle rotation at mid-span, where the spacer is attached to the cables, as well as the spacer deformation and forces acting on the spacer during the vibration of twin, triple and quad conductor bundles. Ice accumulation on a spacer may change the latter's elastic and damping properties, whose influence on the vibration is considered in the model together with the effect of varying cable properties. Simulation results show how the risk of bundle collapse and the load on the spacer is reduced when the number of subconductors in the bundle is increased. The model also predicts that the most important property which can reduce forces acting on the spacer during vibration is spacer damping, whereas the bundle rotation is affected to the greatest extent by cable damping.     

普适计算中一种基于蚁群算法的服务调度模型

针对普适计算环境下对服务调度的高可靠要求，研究人员已提出不少服务调度模型，但都不具有很好的适应性．在现有的服务调度模型基础上，提出了一种新的基于信任的自适应服务调度模型，该模型先基于信任进行首次考核筛选，选出可靠的节点，然后基于蚁群算法进行任务调度．通过计算分析和仿真，验证了该模型的适应性．     

高校自主管理权与大学生受教育权的冲突及平衡

阐述了高校自主管理权的内涵，高校行使自主管理权的法律依据、必要性与合理性；大学生受教育权的含义和内容；分析了高校自主管理权与大学生受教育权的冲突原因；指出了平衡高校自主管理权与大学生受教育权的途径．