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针对人员疏散研究中提取疏散场景行人运动参数的需要,采用数字图像处理技术对记录行人运动的视频进行了处理.首先对背景进行混合高斯建模并提取前景,然后采用mean-shift算法对视频中彼此相连的多个行人目标进行有效地聚类分割并准确地跟踪每个行人,得到了包含有行人运动特性时空信息的运动轨迹,利用轨迹得到了行人在行进过程中的速度变化特征.结果表明该文所提出方法可以方便、快速、准确地提取人员运动特性参数,可望对提取人员疏散实验以及真实场景中行人运动的基础数据,如速度、密度、流量等提供有效的技术手段. 相似文献
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Rosinda Leonor Pato Alexandre O. Tavares 《Journal of Environmental Planning and Management》2016,59(4):607-627
This study analysed the importance of physical forces on land-use change, on the planning framework in a Portuguese periurban area. A temporal matrix showing the trajectories of land transformation was obtained. A multivariate redundancy analysis explored the importance of physical parameters on temporal and spatial land-use change. A content analysis on urban or municipal master plans was made framing the importance of physical parameters on the planning process. The results highlighted a consistent trajectory of profound land-use changes with distinctive trajectories, with increasingly complex patterns with a limited dependence on physical variables. The trajectories were more related to the planning framework, where political actors and planning managers seemed to be most important. A theoretical model balancing three main components – physical forces, actors, and land transformation (DFA-C model) is proposed, reflecting the informal relationships between physical parameters and actors during the planning process. 相似文献
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In underground coal mining, methane explosions often can cause tremendous disasters. In the meantime, carbon monoxide (CO), generated during the process of coal oxidation, may appear in the air. Therefore, the explosion characteristics of the mixture of CH4 and CO must be investigated to prevent gas explosion accidents in coal mines. We conducted experiments by using a 20-L nearly spherical gas explosion testing device. The software FLACS was used to simulate the explosion of the mixture of CH4 and CO at various mixing concentrations, and the simulation results corresponded to experimental results. With the increase of CO concentration, both upper and lower explosive limits of CH4 decreased. On the whole, the explosion characteristic parameters of CH4 and the mixture are similar. When CH4 concentration was below the stoichiometric concentration, the addition of CO could promote the intensity of gas explosion; oppositely, excessive CO would inhibit the gas explosion reaction. The inhibitory effects become more significant as the concentration of CH4 increases. 相似文献
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Akinpelu Kamoru Babayemi Okechukwu Dominic Onukwuli Emeka Emmanuel Eluno John Adebayo Otolorin 《环境质量管理》2021,30(3):43-51
Adsorptive bleaching potentials of activated animal bone on palm oil was investigated. Palm oil was obtained locally from the mesocarp of oil palm fruits. The obtained palm oil was degummed, neutralized, and subjected to proximate analysis before bleaching. The animal bone–based activated carbon used as a bleaching material was locally prepared by cleaning, drying, carbonization, and chemical activation process. The prepared activated carbon (CBAC) was characterized using Fourier transform infrared, scanning electron microscopy, Braummer–Emmett–Teller, and x‐ray diffraction (XRD) methods. Bleaching of the prepared palm oil on CBAC was done at different process conditions. The characterization results of BET analysis show that CBAC has a surface area of 593.270 m2/g, micropore surface area 595.56 m2/g, micropore volume 0.212 cm3/g, Langmuir surface area 1.38e+04 m2/g, and adsorption energy 3.998 KJ/mol. XRD analysis indicates gypsum as the dominant mineral in the activated carbon sample. The CBAC efficiency of 75.14% was obtained for time/temperature interactions at 50 min/120°C while at 25 g/50 min dosage/time interactions an efficiency of 75.17% was obtained. 相似文献
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