种特征

The results offer the condition that these plants of Ajuga could be distinguished by size and ornamentation of exhymenine.

结果表明，同属三种植物的形态特征相似，可通过叶形及花期是否具基生叶，花萼的形态，花冠颜色以及茎的生长方式和植株被毛情况等予以鉴别；通过对三种植物的花、根、茎、叶及全草粉末的组织构造观察，认为种间差异较小，可依据毛茸的分布及形态特征和茎的木化程度不同加以鉴别；对三者花粉粒进行了扫描电镜观察，发现其大小和外壁纹饰具有明显差异，为三者的鉴别提供了有力的依据，也为该属的分类及植物花粉形态研究提供了花粉形态学方面的资料。

In this paper, three types of image data base is proposed, that is, attribute-oriented, feature-oriented and knowledge-oriented; the public fundamental structure of image data base system in each field is implemented, the improved expression of image geometrical feature is given, the strong command language and necessary auxiliary means to manage image data base are designed.

文中提出了图象数据库的3种类型，即面向属性型、面向特征型和面向知识型；实现了各领域上的图象数据库系统共有的基本结构；给出了一种改进的用于表示图象几何特征的方法；设计了一种具有较强功能的命令语言和管理图象数据库所必要的辅助手段。

For Hu invariant moment having no scale invariance, two modified algorithms are proposed: one is based on the normalized central moment coming from the concept of image square and the other is based on constructing a new invariant moment.

主要贡献如下： 1。针对离散情况下Hu不变矩特征仅仅具有平移、旋转不变性，不具有比例不变性的问题，提出了两种改进算法：一种是从图像正方形概念演变而来的归一化中心矩的修正；另一种是重新构造新的不变矩特征。

This paper studys the stability of nonlinear systems in two particular critical cases. In a case, the linear systems at the equilibrium point of interest is assumed to possess a simple zero eigenvalue. In the other case, it is assumed to possess a complex conjugate pair of simple pure imaginary eigenvalue.

本文基于中心流形定理研究了非线性系统在两种特殊临界情形下的稳定性问题，一种是与它相应的线性系统在平衡点仅有零特征根，另一种是与它相应的线性系统在平衡点仅有一对共轭的纯虚数特征根。

For the bottom-up attention process, areas of interest that deserve visual attention are formed by a sequentially extracting of feature map, conspicuity map, and interesting map. Firstly, based on Treisman's feature integration theory and the characteristics of orientation and frequency selective nerve cells in biological cortex, we propose a new 2D optimal quadrature filter in the meaning of minimum energy loss to extract intensity, edge, orientation, symmetry, curvature and comer features to form the feature maps. Then based on the local competent and global cooperative perception character of biological vision, we design a kind of competent/cooperative filter and use a set of such filters to extract conspicuous locations that will most likely to cause visual attention from feature maps to form conspicuity maps.

我们根据Treisman〓的特征整合理论，结合生物视觉皮层的方向、频率敏感性神经元，提出采用一组调制在不同尺度和方向上的新的最佳正交特征滤波器并行地提取图象的亮度、边缘、方向、对称性、曲率和角度等特征作为注意线索，构成特征图；在此基础上，基于生物视觉的局部竞争和全局协作特性，本文设计了一种竞争协作滤波器用于从特征图中提取可能引起视觉注意的显著位置构成显著图，各显著图进一步通过本文提出的融合算法和非线性松弛迭代算法生成自底向上兴趣图。

This paper applies the entropy concept of information theory to feature selection,and defines two information measurements overlap entropy and error entropy that are used to evaluate features.Then the physical meanings of the two definiens are explained.The crucial problem about how to divide the interzones is provided in the following.

将信息论中熵的概念应用到特征选择中，定义了两种信息测度评价特征——误差熵和混叠熵，然后阐述了两种定义的不用物理意义，分析了计算熵中最关键的区间划分问题，并提出一种较好的区间划分方法。

The diagnostic features for the species include deep excavation on the posteroventral margin of the premaxilla, a diastema between the premaxillary and maxillary teeth, a a number of many pits and ridges on the anterolateral surface of the antorbital fossa, the posterolateral process of the parietal being long and sharply posteriorly directed, the column ar -like margin of the pterygoid process of the quadrate, the bifurcated posterior margin of the dentary, a distinctive groove posterior to the anterior carina on the medial surface of the premaxillary tooth crowns, absence of ventrolateral processes on intercentrum of t he atlas, T-shaped centrum of the first caudal in ventral view, transverse process on anterior caudals with rounded , and strongly anteroposteriorly expanded distal end, presence of two fossae separated by an oblique ridge on the lateral side of the anterior chevrons near the articular end, and pubis strongly curved psoteriorly.

这一属种的主要鉴定特征包括：前上颌骨后腹缘有一深凹、前上颌齿和上颌齿之间有一齿缺、眶前窝外表面前部有许多坑窝和脊、顶骨侧后突伸向后方、方骨的翼骨支边缘柱状、靠近前上颌齿齿冠舌面前缘有槽、环椎间椎体外腹突缺失、第一尾椎椎体腹视 T 形、前部尾椎横突远端前后向强烈扩展呈圆形、前部脉弧近端外侧面有两个被一斜脊分离的窝以及耻骨强烈向后弯曲。通过分析千禧中国鸟龙的96个骨骼学特征，发现其中21个特征支持奔龙类与鸟类的亲缘关系最近，9个特征支持奔龙类与伤齿龙类亲缘关系最近，25个特征支持奔龙类、伤齿龙类和鸟类亲缘关系较为接近。

Firstly, those useless to classify texts are filtered according the category document frequency distribution difference of each feature; and then in order to overcome the limitations of TF-IDF weighting formula a novel weighting formula called TF-CDF is presented . Calculate the weight of each feature according to TF-CDF and build the Vector Space Model for the entire corpus. To select significant features, a feature selection approach based on Variable Precision Rough Set is also proposed and implement with some SQL sentences combining the definitions of VPRS with the advantages of SQL sentences.

该文首先根据特征词的类别分布差异进行特征过滤；然后，分析传统的权值公式TF-IDF的缺点，采用改进的权值计算公式简记为TF-CDF，依据TF-CDF公式计算每个特征词的权值，生成文档集的向量空间模型VSM；接着，提出了一种基于可变精度粗糙理论的特征选择进一步选择对分类贡献度大的特征，并用SQL实现。

Basesd on the precipitation difference in Tsaidam Basin of Qinghai Province, three sampling areas, including Geremu, Delinghan and Doulan, were selected, and then three sapmling plots in each sampling area were selected to study the characteristics of plant community which dominated by Ceratoides lateens, Nitraria tangutorum, Tamarix chinensis, Kalidium gracile, Haloxylon ammodendron and Salsola arbuscula respectively. At the same time, the morphological and physiological features of above-mentioned 6 species were measured for probing their drought tolerance. By using the subordinative function method, grey correlative degree analyse and no-weight index comprehensive evaluation method, their drought tolerance were compared as well. The results were showed as follows: The main xeric vegetation types in the desert steppe of Tsaidam Basin were Nitraria tangutorum community, Tamarix chinensis community, Haloxylon ammodendron community, Kalidium gracile+Salsola arbuscula community, Ceratoides lateens+ Haloxylon ammodendron+Kalidium gracile community.

根据青海省柴达木盆地不同地区历年降水量差异，在研究区内选择格尔木、德令哈、都兰3个采样区，每个样区内确定3个采样点(表示为D11、D12、D13、D21、D22、D23、D31、D32、D33)，以样区内唐古特白刺、甘蒙柽柳、梭梭、木本猪毛菜、里海盐爪爪、驼绒藜等6种主要植物为研究对象，通过调查采样地区群落特征，观测植物形态解剖特征，测定植物脯氨酸、可溶性糖、叶绿素、超氧化物歧化酶、过氧化物酶和过氧化氢酶等生理指标，研究了柴达木盆地6种植物抗旱生理特性及抗旱特性，用模糊数学隶属函数法、灰色关联分析和非加权指数评价法分别对6种植物的各个抗旱性指标进行了综合评价。

In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.

这章具体研究了基于三种极化散射特性描述的相应的目标识别方法：①基于极化参数平面描述的目标识别方法，将目标回波极化状态投影到以极化椭圆参数，即椭圆率角ε和倾角τ表征的极化状态平面上，参数随观测频率的变化就形成了图，根据图的变化特点构造了目标的多维极化特征空间，并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构；②基于Poincare极化球面描述的目标识别方法，采用Stokes矢量表征目标回波的极化状态，并将其投影到描述极化状态的Poincare极化球面上，定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息，提取了准方位不变性的目标极化特征，最后设计了目标的识别器结构；③基于频率敏感性描述的目标识别方法，通过在Poincare极化球面上所定义的极化状态距离的概念，研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题，获得了在极化状态距离下的频率分布特性曲线，采用最小二乘估计曲线拟合方法，它既用于极化特征的降维，同时又直接将拟合参数作为目标的分类特征。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。