Polarized Lidar Reflectance Measurements of Vegetation at Near-Infrared and Green Wavelengths

There is growing interest in the use of lidar for remote sensing of vegetation owing to the emergence of reliable and rugged lasers and highly sensitive detectors. Lidar remote sensing has a distinct advantage over conventional techniques in vegetation remote sensing due to its capability for three-dimensional characterization of vegetative targets. The Multiwavelength Airborne Polarimetric Lidar (MAPL) system was developed primarily for vegetation remote sensing applications from an airborne platform of up to 1,000 -m altitude. The lidar system has full waveform capture and polarimetric measurement capability at two wavelengths in the near-infrared (1064 nm) and the green (532 nm) spectral regions. This study presents preliminary ground-based lidar reflectance measurements on a variety of deciduous and coniferous trees under fully foliated conditions with a view towards tree species discrimination. Variations in the reflectance characteristics of selected deciduous trees under unfoliated and fully foliated conditions were also investigated. Our study reveals distinct differences in the reflectance characteristics of various trees.     

The influence of Na<Superscript>+</Superscript> on the anilinepropylsilica xerogel synthesis by using the fluoride nucleophilic catalyst

Anilinepropylsilica xerogel was obtained by using an appropriate organosilane and tetraethyl orthosilicate as precursor reagents. The gelation was carried out using HF and NaF as catalysts. The presence of Na⁺ (when NaF was used) resulted in a decrease in the final organic content of the materials. This effect was interpreted as an inhibition of the organosilane polycondensation possibly due to the Na⁺ interaction with the SiO^- groups of the hydrolyzed organosilane. The presence of Na⁺ also results in morphological changes in the xerogels.     

Local Minimizers of the Ginzburg-Landau Energy with Magnetic Field in Three Dimensions

We establish the existence of locally minimizing vortex solutions to the full Ginzburg-Landau energy in three dimensional simply-connected domains with or without the presence of an applied magnetic field. The approach is based upon the theory of weak Jacobians and applies to nonconvex sample geometries for which there exists a configuration of locally shortest line segments with endpoints on the boundary.Research partially supported by NSERC grant number 261955     

Continuously coupled parametric generators and their quantum statistics

In this paper the quantum-statistical properties of light beams propagating in a directional nonlinear coupler are investigated. This device is composed of a pair of linearly coupled nonlinear waveguides operating by means of degenerate parametric downconversion. The possibility of generation of nonclassical states of light in single and compound modes, using the short-length approximation, is discussed. Influence of linear and nonlinear mismatches for generation of nonclassical light is taken into account. This work was supported by Project LN00A015, Research Project No. CEZ: J14/98 and the COST project OC P11.003 of the Czech Ministry of Education.     

Loading aircraft for military operations

In this paper, we describe an aircraft loading problem submitted by the French military agency (DGA) as part of a more general military airlift planning problem. It can be viewed as a kind of bi-dimensional bin-packing problem, with heterogeneous bins and several additional constraints. We introduce two-phase methods for solving this NP-hard problem. The first phase consists in building good initial solutions, thanks to two fast algorithms: a list-based heuristic and a loading pattern generation method. Both algorithms call a constraint-based subroutine, able to determine quickly if the items already loaded can be reshuffled to accommodate a new object. The second phase improves these preliminary solutions using local search techniques. Results obtained on real data sets are presented.     

ON THE RATE OF WEIGHTED Lp CONVERGENCE BY THE GRUENWALD INTERPOLATORY OPERATORS

This paper gives the weighted Lp convergence rate estimations of the Gruenwald interpolatory polynomials based on the zeros of Chebyshev polymomials of the first kind,and proves that the order of the estimations is optimal for p≥1.     

Reply to Nathan: How to reconstruct the causal argument

Nicholas Nathan tries to resist the current version of the causal argument for sense-data in two ways. First he suggests that, on what he considers to be the correct re-construction of the argument, it equivocates on the sense of proximate cause. Second he defends a form of disjunctivism, by claiming that there might be an extra mechanism involved in producing veridical hallucination, that is not present in perception. I argue that Nathan’s reconstruction of the argument is not the appropriate one, and that, properly interpreted, the argument does not equivocate on proximate cause. Furthermore, I claim that his postulation of a modified mechanism for hallucinations is implausibly ad hoc.     

On the bounded version of Hilbert's tenth problem

 The paper establishes lower bounds on the provability of 𝒟=NP and the MRDP theorem in weak fragments of arithmetic. The theory I ⁵ E ₁ is shown to be unable to prove 𝒟=NP. This non-provability result is used to show that I ⁵ E ₁ cannot prove the MRDP theorem. On the other hand it is shown that I ¹ E ₁ proves 𝒟 contains all predicates of the form (∀i≤|b|)P(i,x)^Q(i,x) where ^ is =, <, or ≤, and I ⁰ E ₁ proves 𝒟 contains all predicates of the form (∀i≤b)P(i,x)=Q(i,x). Here P and Q are polynomials. A conjecture is made that 𝒟 contains NLOGTIME. However, it is shown that this conjecture would not be sufficient to imply 𝒟=N P. Weak reductions to equality are then considered as a way of showing 𝒟=NP. It is shown that the bit-wise less than predicate, ≤₂, and equality are both co-NLOGTIME complete under FDLOGTIME reductions. This is used to show that if the FDLOGTIME functions are definable in 𝒟 then 𝒟=N P. Received: 13 July 2001 / Revised version: 9 April 2002 / Published online: 19 December 2002 Key words or phrases: Bounded Arithmetic – Bounded Diophantine Complexity     

在PowerPoint演示文稿中轻松插入Flash动画

用PowerPoint制作出的幻灯片简洁明快、条理清晰,而且PowerPoint简单易用,非常适合教师上课使用,成为教师制作多媒体课件的工具之一(在我校大部分教师采用PowerPoint制作多媒体课件).在制作多媒体课件过程中,结合适当的媒体技术(动画、声音、文字)不仅能提高课件的直观生动性,激发学生学习兴趣,同时有助于学生对课堂知识的当堂消化和理解,加深记忆.通过我校开展多媒体教学多年的实践发现:对医科学生的基础课、专业基础课和专业课教学中广泛涉及的机能性、原理性的知识适当采用动画其教学效果是传统教学方法无法比拟的.在众多的动画媒体中(avi、mov、mpg、swf、gif、ram等),Flash动画(swf文件)以其作品容量小(单个swf文件通常不到100 K)、质量高和丰富的交互性,特别是近年推出的Flash5同时能结合视频和音频,成为目前最为流行的二维动画.不仅为网页制作增添了活力,同时也为多媒体制作提供了有效的手段,既精巧又实用,素有"闪客"、"动画精灵"之美誉,越来越受到人们的青睐.如果要把Flash制作好的动画插入到PowerPoint制作的课件中,将会使PowerPoint单调的动画增色不少,使课件更具魅力.为此,我校专门开展了一系列Flash动画制作讲座,广大教师都能结合本专业制作Flash动画.如何将Flash动画加入到PowerPoint中,不少教师都是直接通过"超级连接"导入Flash课件,放映时总会出现讨厌的警告信息和警告声音提示,点击确定后打开Flash课件,有时打开的Flash课件窗口还要重新调整,使用十分不便.如何才能更恰当地引入Flash动画呢?不少杂志刊物和网上发表过类似文章,但大都比较复杂,而且在使用中特别是在PowerPoint中放映Flash动画偶尔会出现这样和那样的问题,这也是我们教学工作中经常遇到的问题,具有一定的普遍性.经过与教师们的众多交流和笔者平时反复摸索,找到了较为简便有效的方法,写出来与大家分享.