Pre-Attentive and Attentive Detection of Humans in Wide-Field Scenes

We address the problem of localizing and obtaining high-resolution footage of the people present in a scene. We propose a biologically-inspired solution combining pre-attentive, low-resolution sensing for detection with shiftable, high-resolution, attentive sensing for confirmation and further analysis. The detection problem is made difficult by the unconstrained nature of realistic environments and human behaviour, and the low resolution of pre-attentive sensing. Analysis of human peripheral vision suggests a solution based on integration of relatively simple but complementary cues. We develop a Bayesian approach involving layered probabilistic modeling and spatial integration using a flexible norm that maximizes the statistical power of both dense and sparse cues. We compare the statistical power of several cues and demonstrate the advantage of cue integration. We evaluate the Bayesian cue integration method for human detection on a labelled surveillance database and find that it outperforms several competing methods based on conjunctive combinations of classifiers (e.g., Adaboost). We have developed a real-time version of our pre-attentive human activity sensor that generates saccadic targets for an attentive foveated vision system. Output from high-resolution attentive detection algorithms and gaze state parameters are fed back as statistical priors and combined with pre-attentive cues to determine saccadic behaviour. The result is a closed-loop system that fixates faces over a 130 deg field of view, allowing high-resolution capture of facial video over a large dynamic scene.     

Mobile robot path planning based on hierarchical hexagonal decomposition and artificial potential fields

In this article, a new algorithm based on an artificial potential field and hierarchical cell decomposition technique is developed to solve the find-path problem for a mobile robot. The complete map of the workspace including obstacle locations is assumed to be known a priori. The basic cell structure used for decomposition is a hexagon. The artificial potential field is based on an attractive force from the goal position and repelling forces from the obstacles. Computer simulations of the algorithm for various obstacle scenarios are also presented. © 1994 John Wiley & Sons, Inc.     

一种性能可调的新型节能材料－电致变色膜

本文介绍了一种性能可调的新型节能材料—电致色薄膜，描述了以其为核心的全固态灵巧窗结构、工作原理和光学调节性能，回顾了电致色材料、离子存储层和固态锂离子导体及其性质，并展望了这种新型节能材料的应用。     

Thermal decoloration kinetics of spirooxazines in Ormocer coatings prepared via sol-gel processing

Two free and one silylated (silane-substituted) photochromic spirooxazines are doped into organically modified ceramics (Ormocer) coatings by sol-gel processing and the thermal decoloration kinetics of these coatings are investigated and compared with the corresponding ethanol solutions and PMMA coatings. The decoloration behaviour of the two free dyes (SO-1 and SO-2) in the Ormocer coatings is similar to that in ethanol solutions, obeying a first-order mechanism and possessing almost the same decoloration rates as in ethanol. This suggests that the dye molecules encapsulated within the pores of the solid matrix are as free as those in ethanol solutions. The silylated dye (SO-3) in the Ormocer coatings, however, exhibits a considerably lower decoloration rate than the corresponding free dye (SO-1) and evident deviation from the first-order mechanism. This indicates apparently that the degree of freedom of the dye molecules is reduced by the silylation. These results are discussed on the basis of solvent polarity, porous structure of the Ormocer coating, and the dye-to-matrix connectivity.     

Interdiffusion behavior of Hg in HgTe/CdTe superlattices grown on Cd0.96Zn0.04 Te (211)B substrates by molecular beam epitaxy

Double-crystal x-ray rocking curve (DCRC) and secondary-ion mass-spectroscopy (SIMS) measurements have been performed to investigate the effect of rapid thermal annealing on the interdiffusion behavior of Hg in HgTe/CdTe superlattices grown on Cd_0.96Zn_0.04Te (211)B substrates by molecular beam epitaxy. The sharp satellite peaks of the DCRC measurements on a 100-period HgTe/CdTe (100Å/100Å) superlattice show a periodic arrangement of the superlattice with high-quality interfaces. The negative direction of the entropy change obtained from the diffusion coefficients as a function of the reciprocal of the temperature after RTA indicates that the Hg diffusion for the annealed HgTe/CdTe superlattice is caused by an interstitial mechanism. The Cd and the Hg concentration profiles near the annealed HgTe/CdTe superlattice interfaces, as measured by SIMS, show a nonlinear behavior for Hg, originating from the interstitial diffusion mechanism of the Hg composition. These results indicate that a nonlinear interdiffusion behavior is dominant for HgTe/CdTe superlattices annealed at 190°C and that the rectangular shape of HgTe/CdTe superlattices may change to a parabolic shape because of the intermixing of Hg and Cd due to the thermal treatment.     

Experimental densities for compressed R134a

This paper reports densities of compressed R134a (1,1,1,2-tetrafluoroethane) determined by using a contiuously weighed pycnometer at 20 K intervals between 180 and 380 K at pressures from slightly greater than the vapour pressure to 70 MPa. The results are accurate to within ±0.1%. Saturated liquid densities derived by extrapolation from the experimental values agree with other reported values to within ±0.3%.     

新增探明储量的经济可采储量计算方法

提出了新增探明储量有无经济可采储量的判别方法。在此基础上，通过对立已开发油田技术可采储量经济转化率与油藏空气渗透率的相关关系式和图版，根据储层的空气渗透率，计算新增探明储量的经济转化率和经济可采储量。该方法参数易取，计算简便，对于快速、准确计算新增探明储量的经济可采储量具有重要意义。