University of Science and Technology Beijing

About: University of Science and Technology Beijing is a education organization based out in Beijing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 41558 authors who have published 44473 publications receiving 623229 citations. The organization is also known as: Beijing Steel and Iron Institute.

A Short Survey of Recent Advances in Graph Matching

Abstract: Graph matching, which refers to a class of computational problems of finding an optimal correspondence between the vertices of graphs to minimize (maximize) their node and edge disagreements (affinities), is a fundamental problem in computer science and relates to many areas such as combinatorics, pattern recognition, multimedia and computer vision. Compared with the exact graph (sub)isomorphism often considered in a theoretical setting, inexact weighted graph matching receives more attentions due to its flexibility and practical utility. A short review of the recent research activity concerning (inexact) weighted graph matching is presented, detailing the methodologies, formulations, and algorithms. It highlights the methods under several key bullets, e.g. how many graphs are involved, how the affinity is modeled, how the problem order is explored, and how the matching procedure is conducted etc. Moreover, the research activity at the forefront of graph matching applications especially in computer vision, multimedia and machine learning is reported. The aim is to provide a systematic and compact framework regarding the recent development and the current state-of-the-arts in graph matching.

Characteristics of atmospheric ammonia over Beijing, China

Abstract: . Continuous measurements of atmospheric ammonia (NH 3 ) were conducted using Ogawa passive samplers from February 2008 to July 2010 at an urban site and from January 2007 to July 2010 at a rural site in Beijing, China. NH 4 + in fine particles was also collected at the rural site during 2008–2009. The field comparison between the Ogawa passive samplers and an active analyzer for NH 3 conducted at the urban site assures the quality and accuracy of the measurements. The concentrations of NH 3 at the urban site ranged from 0.7 to 85.1 ppb, with the annual average of 18.5 ± 13.8 and 23.5 ± 18.0 ppb in 2008 and 2009, respectively. The NH 3 concentrations at the rural site were lower than those at urban site, and varied from 0.8 to 42.9 ppb, with the annual average of 4.5 ± 4.6, 6.6 ± 7.0 and 7.1 ± 3.5 ppb in 2007, 2008 and 2009, respectively. The data showed marked seasonal variations at both sites. The results emphasized traffic to be a significant source of NH 3 concentrations in winter in urban areas of Beijing. This was illustrated by the strong correlations of NH 3 with the traffic related pollutants (NO x and CO) and also by the bimodal diurnal cycle of NH 3 concentrations that was synchronized with traffic. Similar patterns were not observed during the summer, suggesting other non-traffic sources became more important. At the rural site, the daily NH 4 + concentrations ranged from 0.10 to 36.53 μg m −3 , with an average of 7.03 μg m −3 from June 2008 to December 2009. Monthly NH 3 were significantly correlated with NH 4 + concentrations. Average monthly NH 3 /NH 4 + ratios varied from 0.13 to 2.28, with an average of 0.73. NH 4 + in PM 2.5 was primarily associated with SO 4 −2 at the rural site.