苹果轻微机械损伤高光谱图像无损检测

无损检测是高光谱遥感应用研究热点之一。苹果在采摘、运输过程中易发生轻微机械损伤而影响其品质。使用高光谱成像系统分别采集54个轻微损伤的“黄香蕉”与“烟台富士”苹果可见-近红外波段(400~1 000 nm)的图像,提取苹果损伤区域的均值波谱曲线,对其进行最小噪声分离变换和基于几何顶点端元原理提取端元波谱,计算损伤区域波谱和端元波谱的光谱角,构建了端元提取光谱角苹果轻微机械损伤检测模型。通过设定光谱角阈值分别检测“黄香蕉”与“烟台富士”苹果轻微机械损伤,并与MNF变换、PCA方法检测精度进行对比分析,结果表明EESA模型检测苹果轻微机械损伤的精度最高,检测正确率分别达到94.44%和90.07%。     

Preparation of Surface-enhanced Raman Scattering(SERS)-active Optical Fiber Sensor by Laser-induced Ag Deposition and Its Application in Bioidentification of Biotin/Avidin

A surface-enhanced Raman scattering(SERS) optical fiber sensor was prepared by the laser-induced deposition of Ag nanoparticle membrane on a silica optical fiber tip, which was applied to the real time SERS spectral monitoring on the biorecognition of biotin/avidin. The bioidentification of biotin/avidin was carried out through a indirect method, in which the bioidentification is based on the SERS response signal of a labeled dye(Atto610) after its fluorescence has been quenched totally by the deposited Ag nanoparticle membrane. By SERS monitoring the bioidentification process of biotin/avidin, it has been found that this recognition process is finished in 40 min. The lowest detection concentration of biotin is 1.0×10^-7 mg/mL. This research is promising in the application of immunoassays on line and in vivo.     

层次分析法判断矩阵可靠性探讨

层次分析法判断矩阵中可能会存在相互矛盾的一系列判断元素.通过一个房产评估例子论述这种矛盾造成的原因.为解决这类矛盾,对层次分析法的判断矩阵进行改进:判断矩阵的元素不是通过直接两两比较重要性而得,而是首先按照一定的标准建立评分矩阵,然后对评分矩阵进行矩阵变换形成判断矩阵.根据AHP法改进判断矩阵形成的过程,提出判别层次分析法判断矩阵可靠性的方法.     

N指标d维广义Wiener过程象集的一个性质

设W（t）是N指标d维广义Winener过程,A↓Borel集W1,…,Em包含R^N,本文研究了W（t）象集的m项代数和W（E1）＋W（E2）＋…＋W（En）内点的存在性的问题。     

Enumerating edge-constrained triangulations and edge-constrained non-crossing geometric spanning trees

In this paper, we present algorithms for enumerating, without repetitions, all triangulations and non-crossing geometric spanning trees on a given set of n points in the plane under edge inclusion constraint (i.e., some edges are required to be included in the graph). We will first extend the lexicographically ordered triangulations introduced by Bespamyatnikh to the edge-constrained case, and then we prove that a set of all edge-constrained non-crossing spanning trees is connected via remove-add flips, based on the edge-constrained lexicographically largest triangulation. More specifically, we prove that all edge-constrained triangulations can be transformed to the lexicographically largest triangulation among them by O(n²) greedy flips, i.e., by greedily increasing the lexicographical ordering of the edge list, and a similar result also holds for a set of edge-constrained non-crossing spanning trees. Our enumeration algorithms generate each output triangulation and non-crossing spanning tree in O(loglogn) and O(n²) time, respectively, based on the reverse search technique.     

On the Maximum Number of Edges in Topological Graphs with no Four Pairwise Crossing Edges

A topological graph is called k -quasi-planar if it does not contain k pairwise crossing edges. It is conjectured that for every fixed k, the maximum number of edges in a k-quasi-planar graph on n vertices is O(n). We provide an affirmative answer to the case k=4.     

On Regular Vertices of the Union of Planar Convex Objects

Let be a collection of n compact convex sets in the plane such that the boundaries of any pair of sets in intersect in at most s points for some constant s≥4. We show that the maximum number of regular vertices (intersection points of two boundaries that intersect twice) on the boundary of the union U of is O ^*(n ^4/3), which improves earlier bounds due to Aronov et al. (Discrete Comput. Geom. 25, 203–220, 2001). The bound is nearly tight in the worst case. In this paper, a bound of the form O ^*(f(n)) means that the actual bound is C _ε f(n)⋅n ^ε for any ε>0, where C _ε is a constant that depends on ε (and generally tends to ∞ as ε decreases to 0). Work by János Pach and Micha Sharir was supported by NSF Grant CCF-05-14079, and by a grant from the U.S.–Israeli Binational Science Foundation. Work by Esther Ezra and Micha Sharir was supported by grant 155/05 from the Israel Science Fund and by the Hermann Minkowski–MINERVA Center for Geometry at Tel Aviv University. Work on this paper by the first author has also been supported by an IBM Doctoral Fellowship. A preliminary version of this paper has been presented in Proc. 23nd Annu. ACM Sympos. Comput. Geom., 2007, pp. 220–226. E. Ezra’s current address: Department of Computer Science, Duke University, Durham, NC 27708-0129, USA. E-mail: esther@cs.duke.edu     

Coloring Geometric Range Spaces

We study several coloring problems for geometric range-spaces. In addition to their theoretical interest, some of these problems arise in sensor networks. Given a set of points in ?² or ?³, we want to color them so that every region of a certain family (e.g., every disk containing at least a certain number of points) contains points of many (say, k) different colors. In this paper, we think of the number of colors and the number of points as functions of k. Obviously, for a fixed k using k colors, it is not always possible to ensure that every region containing k points has all colors present. Thus, we introduce two types of relaxations: either we allow the number of colors used to increase to c(k), or we require that the number of points in each region increases to p(k).Symmetrically, given a finite set of regions in ?² or ?³, we want to color them so that every point covered by a sufficiently large number of regions is contained in regions of k different colors. This requires the number of covering regions or the number of allowed colors to be greater than k.The goal of this paper is to bound these two functions for several types of region families, such as halfplanes, halfspaces, disks, and pseudo-disks. This is related to previous results of Pach, Tardos, and Tóth on decompositions of coverings.