Vehicle speed measurement based on gray constraint optical flow algorithm

Vehicle speed measurement (VSM) based on video images represents the development direction of speed measurement in the intelligent transportation systems (ITS). This paper presents a novel vehicle speed measurement method, which contains the improved three-frame difference algorithm and the proposed gray constraint optical flow algorithm. By the improved three-frame difference algorithm, the contour of moving vehicles can be detected exactly. Through the proposed gray constraint optical flow algorithm, the vehicle contour's optical flow value, which is the speed (pixels/s) of the vehicle in the image, can be computed accurately. Then, the velocity (km/h) of the vehicles is calculated by the optical flow value of the vehicle's contour and the corresponding ratio of the image pixels to the width of the road. The method can yield a better optical flow field by reducing the influence of changing lighting and shadow. Besides, it can reduce computation obviously, since it only calculates the moving target contour's optical flow value. Experimental comparisons between the method and other VSM methods show that the proposed approach has a satisfactory estimate of vehicle speed.     

Cervical spondylosis: Evaluation of microstructural changes in spinal cord white matter and gray matter by diffusional kurtosis imaging

Introduction

We investigated microstructural changes in the spinal cord, separately for white matter and gray matter, in patients with cervical spondylosis by using diffusional kurtosis imaging (DKI).

Methods

We studied 13 consecutive patients with cervical myelopathy (15 affected sides and 11 unaffected sides). After conventional magnetic resonance (MR) imaging, DKI data were acquired by using a 3 T MR imaging scanner. Values for fractional anisotropy (FA), apparent diffusion coefficient (ADC), and mean diffusional kurtosis (MK) were calculated and compared between unaffected and affected spinal cords, separately for white matter and gray matter.

Results

Tract-specific analysis of white matter in the lateral funiculus showed no statistical differences between the affected and unaffected sides. In gray matter, only MK was significantly lower in the affected spinal cords than in unaffected spinal cords (0.60 ± 0.18 vs. 0.73 ± 0.13, P = 0.0005, Wilcoxon’s signed rank test).

Conclusions

MK values in the spinal cord may reflect microstructural changes and gray matter damage and can potentially provide more information beyond that obtained with conventional diffusion metrics.     

基于纹理特征和形态学特征融合的高光谱影像分类法

针对传统融合空间和光谱特征方法仅使用单一空间特征,并未充分利用其双高分辨率的特点,提出了一种基于纹理特征和形态学特征融合的高光谱影像分类方法.首先利用传统主成份分析变换降低高光谱影像的维数,消除空间相关性,然后对每一主成分采用灰度共生矩阵提取纹理特征,获得扩展纹理特征,最后结合形态学特征和部分光谱特征进行高光谱影像的分类.实验证明,本文提出的方法能更好地克服传统光谱特征分类的局限性,提高高光谱影像的分类准确度.     

体外分阶段共培养法扩增的脐血造血干/祖细胞移植于NOD/SCID小鼠的实验研究

研究用分阶段共培养法进行体外扩增的脐血造血干/祖细胞对NOD/SCID小鼠重建造血功能的作用,探讨新扩增技术体系对将来临床移植的可行性.分离脐血单个核细胞,分别用rhSCF+rhG-CSF+rhMDGF组合(非共培养组合)和rhSCF+rhG-CSF+rhMDGF+人骨髓间充质干细胞组合(共培养组合)进行脐血造血干/祖细胞的体外扩增,并对扩增细胞进行流式细胞术和细胞集落形成能力分析.在移植实验中,将经致死剂量射线照射后的NOD/SCID小鼠随机分为3组,每组10只.A组:每只移植8.5×106个用rhSCF+rhG-CSF+rhMDGF+人骨髓间充质干细胞组合扩增的细胞;B组:每只移植8.5×106个用rhSCF+rhG-CSF+rhMDGF组合扩增的细胞;C组:每只仅输注0.5 mL生理盐水.移植后定期眼眶底部采血,分析重建造血.12周后取存活小鼠骨髓,检测人特异Alu基因的存在率.实验结果表明,rhSCF+rhG-CSF+rhMDGF+人骨髓间充质干细胞组合的共培养法显著提高了造血干/祖细胞的扩增倍数,并且有利于造血干/祖细胞的自我更新和提高细胞集落形成能力.两种组合扩增的细胞移植小鼠12 d后,小鼠的白细胞类群开始回升,25 d后基本恢复到了基数水平.在45～55 d后小鼠细胞有明显的第2个恢复期,并且共培养组合扩增细胞移植的小鼠中第2次恢复明显快于非共培养组合.12周后在两种组合移植的小鼠中检测到人特异Alu序列片段的概率分别为87.5%(7/8)和88.9%(8/9).由此可推论,分阶段共培养扩增体系有效地提高了脐血造血干/祖细胞的扩增能力和重建造血能力.     

灰色双矩阵博弈模型及其均衡解

在支付矩阵和约束条件都是灰色的情况下,给出灰双矩阵博弈的一般形式,并且定义了灰双矩阵博弈的均衡解,证明灰双矩阵博弈的均衡解可由求解一个非线性规划问题得到.     

环F2+uF2+vF2上自对偶码的两种构造方法

本文研究环R=F2+uF2+vF2上的自对偶码问题.利用Rn到F3n2的Gray映射及R上的自对偶码C的Gray像为F2上自对偶码,获得了R上任何偶长度的自对偶码存在性的结论.最后,给出了R上两种构造自对偶码的方法.     

Galois LCD codes over mixed alphabets

In this work we give a characterization of Galois Linear Complementary Dual codes and Galois-invariant codes over mixed alphabets of finite chain rings, which leads to the study of the Gray image of ${\mathbb{F}}_p{\mathbb{F}}_p[\theta ]$-linear codes, where $p\in \{2;3\}$ and $\theta \ne {\theta }^2=0$ that provides LCD codes over ${\mathbb{F}}_p$.     

Linearity and classification of ZpZp2-linear generalized Hadamard codes

The ${\mathbb{Z}}_p{\mathbb{Z}}_{p^2}$-additive codes are subgroups of ${\mathbb{Z}}_p^{{\alpha }_1}\times {\mathbb{Z}}_{p^2}^{{\alpha }_2}$, and can be seen as linear codes over ${\mathbb{Z}}_p$ when ${\alpha }_2=0$, ${\mathbb{Z}}_{p^2}$-additive codes when ${\alpha }_1=0$, or ${\mathbb{Z}}_2{\mathbb{Z}}_4$-additive codes when $p=2$. A ${\mathbb{Z}}_p{\mathbb{Z}}_{p^2}$-linear generalized Hadamard (GH) code is a GH code over ${\mathbb{Z}}_p$ which is the Gray map image of a ${\mathbb{Z}}_p{\mathbb{Z}}_{p^2}$-additive code. Recursive constructions of ${\mathbb{Z}}_p{\mathbb{Z}}_{p^2}$-additive GH codes of type $({\alpha }_1,{\alpha }_2;t_1,t_2)$ with $t_1,t_2\ge 1$ are known. In this paper, we generalize some known results for ${\mathbb{Z}}_p{\mathbb{Z}}_{p^2}$-linear GH codes with $p=2$ to any $p\ge 3$ prime when ${\alpha }_1\ne 0$, and then we compare them with the ones obtained when ${\alpha }_1=0$. First, we show for which types the corresponding ${\mathbb{Z}}_p{\mathbb{Z}}_{p^2}$-linear GH codes are nonlinear over ${\mathbb{Z}}_p$. Then, for these codes, we compute the kernel and its dimension, which allow us to classify them completely. Moreover, by computing the rank of some of these codes, we show that, unlike ${\mathbb{Z}}_4$-linear Hadamard codes, the ${\mathbb{Z}}_{p^2}$-linear GH codes are not included in the family of ${\mathbb{Z}}_p{\mathbb{Z}}_{p^2}$-linear GH codes with ${\alpha }_1\ne 0$ when $p\ge 3$ prime. Indeed, there are some families with infinite nonlinear ${\mathbb{Z}}_p{\mathbb{Z}}_{p^2}$-linear GH codes, where the codes are not equivalent to any ${\mathbb{Z}}_{p^s}$-linear GH code with $s\ge 2$.