Image retrieval with hierarchical matching pursuit

A novel representation of images for image retrieval is introduced in this paper, by using a new type of feature with remarkable discriminative power. Despite the multi-scale nature of objects, most existing models perform feature extraction on a fixed scale, which will inevitably degrade the performance of the whole system. Motivated by this, we introduce a hierarchical sparse coding architecture for image retrieval to explore multi-scale cues. Sparse codes extracted on lower layers are transmitted to higher layers recursively. With this mechanism, cues from different scales are fused. Experiments on the Holidays dataset show that the proposed method achieves an excellent retrieval performance with a small code length.Comment: 5 pages, 6 figures, conferenc

Metal based reactive nanocomposites prepared by cryomilling

Aluminum is one of the most commonly used metal fuel additives for propellants, explosives, and pyrotechnics. Recent interest has been focused on replacements for aluminum as fuel additives to achieve higher combustion temperatures and stronger pressure pulses for applications in advanced munitions systems. Two applications are addressed in this work. In the applications for explosives designed to defeat stockpiles of chemical and biological weapons, it is of interest to develop multifunctional materials combining the high energy density of metal fuels with the biocidal activity of halogens. A challenge of this effort is to design and prepare powder-like Al-I2 materials which can be used as drop-in replacements for pure aluminum powders in aluminized energetic formulations. For another application, it is desired to tailor combustion dynamics of aluminum in order to fully exploit its high reaction energy by modifying its surface and structure. Hydrocarbons with good volatility and reactivity are selected as additives to composite aluminum- based powders to achieve improved combustion dynamics. For both applications, mechanical milling offers a scalable and versatile method for modifying aluminum. The mechanical milling-based approach is explored in this effort using milling at the liquid nitrogen temperatures, or cryomilling, which enables mixing aluminum with materials that are unstable or difficult to process at room temperatures. Two types of composite materials are prepared and characterized: Al-I2 and Al-hydrocarbon (where wax, low density polyethylene and cyclooctane were used as different hydrocarbon components). Powders prepared by cryomilling are evaluated using Thermogravimetry Analysis (TGA), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). TGA results suggest that iodine is bound to Al, while hydrocarbon is present as a coating on the surface of fine Al grains and composite particles. Very fine, nano-scale particles can be prepared for composites milled at the liquid nitrogen temperature. Ignition temperatures are determined at heating rates in the range of 2000 - 35000 K/s using an electrically heated filament. Constant volume explosion experiments are used to characterize combustion performance of the produced powders. Materials are fed into an oxygen-acetylene flame to observe their burning characteristics and to measure the combustion temperature. The burn time and temperature as a function of particle size are measured using a single particle combustion measurement. Al-I2 powders are supplied to University of Cincinnati for independent evaluation of the biocidal properties of their combustion products. Ignition temperatures of the prepared materials are substantially reduced compared to Al. Burn rates for individual particles are comparable or somewhat lower than for pure Al. Combustion temperatures for the prepared composites are close to those of pure Al. Independent tests show that Al-I2 materials added to hydrocarbon flame substantially improve inactivation of the aerosolized biologically viable spores. The experiments show that combustion dynamics of the prepared Al-hydrocarbon composites is improved compared to pure Al powders

A Case Study of IELTS in Mainland China

This essay is a case study of IELTS use in mainland China, discussing the language assessment from three aspects: the purposes for testing, ethical problems of IELTS, and technologies applied in IELTS. It is worth noting that there are two types of IELTS: academic IELTS and general training IELTS, offered jointly by the British Council, Cambridge English Language Assessment, and other committees. This essay is confined to academic IELTS

A Design Framework for Online Support Systems of E-Government in China

With development of e-government systems, there are many big changes in Chinese government’s efficiency. However, the SARS revealed low efficiency is still serious. After the analysis of the factors affected on the efficiency, we find that traditional DSS is hard to support decision maker and that online support systems may improve the officials’ work effectiveness better. Unfortunately, little attention has been given to the research. In this paper, we will discuss the cultural characteristics of Chinese government. And then, based on the theory of Time-based Competition in governmental workflow, we summarize the four characteristics of online support systems. Furthermore, we propose the design framework for online support systems (OSS) in context of e-government in China, which consists of three major parts: the single OSS, the collaborative OSS and the mobile OSS. Also the detailed function and procedure of the three parts are presented. Analysis shows that the OSS contributes to developing efficiency in the official decision making

Fast parallel algorithms for the unit cost editing distance between trees

1. Problem Ordered labeled trees are trees whose nodes are labeled and in which the ° left-to-right order among siblings is significant. We consider the distance between two trees to be the minimum number of edit operations (insert, delete, and modify) necessary to transform one tree to another. We present three algorithms to find the distance. The first algorithm is a simple dynamic program-ming algorithm based on a postorder traversal whose complexity improves upon the best previ-ously published algorithm due to Tai (T79 in JACM). The second and third algorithms are parallel algorithms based on the application of suf-fix trees to the comparison problem. The cost of executing these algorithms is a monotonic increas-ing function of the distance between the two trees. Results Let trees T I and T2 have numbers of levels L i and L 2 respectively. Let k be the actual distance between T 1 and T2. Let N be rain (IT11, IT2]). The asymptotic running times (assuming a concurrent-read concurrent-write parallel random access machine) are: A lgor i thm T ime Processors Tai IT l lX [T2[xL~XL] Alg l [Tx [ × Ir=l xLI×L

Influence of stirring speed on SiC particles distribution in A356 liquid

A straight-blade mechanical stirrer was designed to stir A356-3.5vol%SiCp liquid in a cylindrical crucible with the capability of systematically investigating the influence of rotating speed of stirrer on the distribution of SiC particles in A356 liquid. The experimental results show that the vertical distribution of SiC particles in A356 liquid can be uniform when the rotating speed of stirrer is 200 rpm, but the radial distribution of SiC particles in A356 liquid is always nonhomogeneous regardless of the rotating speed of stirrer. The radial centrifugalization ratio of SiC particles in A356 liquid between the center and the periphery of crucible increases with the rotating speed of stirrer. The results were explained in the light of SiC particles motion subject to a combination of stirring and centrifugal effect