SOINN-Based Abnormal Trajectory Detection for Efficient Video Condensation

With the evolution of video surveillance systems, the requirement of video storage grows rapidly; in addition, safe guards and forensic officers spend a great deal of time observing surveillance videos to find abnormal events. As most of the scene in the surveillance video are redundant and contains no information needs attention, we propose a video condensation method to summarize the abnormal events in the video by rearranging the moving trajectory and sort them by the degree of anomaly. Our goal is to improve the condensation rate to reduce more storage size, and increase the accuracy in abnormal detection. As the trajectory feature is the key to both goals, in this paper, a new method for feature extraction of moving object trajectory is proposed, and we use the SOINN (Self-Organizing Incremental Neural Network) method to accomplish a high accuracy abnormal detection. In the results, our method is able to shirk the video size to 10% storage size of the original video, and achieves 95% accuracy of abnormal event detection, which shows our method is useful and applicable to the surveillance industry.     

Ultralight and robustly compressible silica aerogel enhanced by AC/C sponge with high oil/water separation

Journal of Porous Materials - In recent years, oil spills and industrial organic pollutants have caused irreparable damage to the environment and biological ecosystems. Therefore, the treatment of...     

An integrated model for analysing the effects of ultrasonic vibration on tool torque and thermal processes in friction stir welding

An integrated model of ultrasonic vibration enhanced friction stir welding (UVeFSW) is developed by integrating the thermal-fluid model with the ultrasonic field model and tool torque model. The tool torque and the heat generation rate at tool/workpiece contact interfaces are coupled with the interfacial temperature, strain rate and ultrasonic energy density. The model is used in quantitatively analysing the effects of ultrasonic vibration on tool torque and thermal processes in friction stir welding (FSW). The results show that ultrasonic vibration reduces the flow stress, which results in a decreasing of tool torque, interfacial heat generation rate and interfacial temperature. The complicated interaction of ultrasonic energy with the thermal processes in FSW leads to a gentle thermal gradient and an enhanced plastic material flow in UVeFSW. The model is validated by a comparison of the calculated thermal cycles and tool torque at various welding parameters with the experimentally measured ones.     

国外某高磷鲕状赤铁矿直接还原—磁选降磷研究

以国外某高磷鲕状赤铁矿为研究对象进行脱磷研究，该高磷矿铁品位为55.81%，磷含量为0.72%，铁矿物主要为磁铁矿和赤铁矿，48.61%的磷存在于磷酸盐中，47.22%的磷分布于铁矿物中。研究了脱磷剂用量、秸秆炭用量、还原温度以及还原时间对粉末还原铁指标的影响。结果表明：无脱磷剂碳酸钙时，无法获得合格的指标；在碳酸钙用量为25%，秸秆炭用量为12.5%，还原温度1 200 ℃，还原时间为75 min，还原产品两段磨矿两段磁选的条件下，可获得铁品位、铁回收率以及磷含量分别为94.27%、87.34%以及0.077%的粉末还原铁，该产品可作为电炉炼钢的优质原料。不加添加剂时，部分含磷矿物被还原成单质磷进入到金属铁中，故粉末还原铁磷含量较高，当碳酸钙用量为25%时，含磷矿物的还原受到抑制而保留在脉石相中，可实现降磷目的，而还原时间过长时，磷仍在脉石相中，铁颗粒将部分含磷矿物包裹，磨矿难以分离，导致磷含量升高。     

Overland Flow along Stone Covered Slope Land Simulated with Semi-Analytical and Numerical Models

Overland flow is an important hydrological response of catchments to rainstorms and contributes to soil erosion and nutrient loss. The kinematic wave model is known to describe the transformation of rainfall to overland flow. Through this, field studies were conducted on a hillslope to simulate water scouring from upstream with a complex surface condition, which was covered with different sizes and percentages of stones. Existing semi-analytical and numerical models were adopted to describe the overland flow in the field. Results indicate that both semi-analytical and numerical models could be applied to describe the process of overland flow. Furthermore, predicted outflow rates by the semi-analytical and the numerical model showed strong correlation with the field measured outflow rates, respectively (NS?=?(0.926, 0.942, 0.992), RE?=?(5.5%, 4.7%, 1.7%) for the semi-analytical model, and NS?=?(0.817, 0.952, 0.992), RE?=?(5.5%, 5.5%, 2.1%) for the numerical model). Besides, hydraulic parameters (Reynolds number-Re, Froude numbers-Fr, Darcy-Weisbach-f, hydraulic shear stress-τ, stream power-ω, water wave celerity-v_w) at any time and distance could be described by the semi-analytical method, and the parameter n/h (an important factor indicating the energy of water and wave flow celerity) could successfully characterize the average hydraulic parameters, and all of the hydraulic parameters are fitted to the expression of y?=?a(n/h)^b.

     

退火温度对新型锆合金薄板带材析出相和织构的影响

采用扫描电镜和超高分辨透射电镜,对具有良好冲制性能的新型锆合金薄板成品带材进行含晶粒、第二相粒子等在内的显微组织研究,并探索真空退火处理条件下温度对带材显微组织的影响。结果显示:新型锆合金薄板成品带材晶粒平均尺寸2.17 μm,存在{0001}<1010>和{0001}<1120>两种织构,大部分晶粒<1120>平行带材RD方向,较少晶粒<1010>平行带材RD方向;第二相粒子分布在晶粒内部及晶界,平均尺寸114 nm,尺寸较大的为不规则椭圆形的Zr-Nb-Fe相,尺寸较小的为圆形的β-Nb相;热处理退火温度降低,带材晶粒尺寸减小,第二相粒子细小弥散分布;新型锆合金薄板成品带材良好冲制性能主要源于轧制积累应变诱发再结晶过程进行充分,导致晶粒细小及孪晶发生破碎;相对轧制变形,退火对带材冲制性能影响不显著。