Video object segmentation by 2-D mesh-based motion analysis

Video object extraction is a key technology in content-based video coding.A novel video object extracting algorithm by two Dimensional (2-D) mesh-based motion analysis is proposed in this paper.Firstly,a 2-D mesh fitting the original frame image is obtained via feature detection algorithm. Then,higher order statistics motion analysis is applied on the 2-D mesh representation to get an initial motion detection mask.After post-processing,the final segmenting mask is quickly obtained.And hence the video object is effectively extracted.Experimental results show that the proposed algorithm combines the merits of mesh-based segmenting algorithms and pixel-based segmenting algorithms,and hereby achieves satisfactory subjective and objective performance while dramatically increasing the segmenting speed.     

Half Mode Substrate Integrated Waveguide (HMSIW) Directional Filter

A double-loop directional filter is described and realized in this work by using a novel guided-wave structure called half mode substrate integrated waveguide (HMSIW), which retains the attractive performances of substrate integrated waveguide (SIW) with a nearly half reduction in size compared to the original SIW version. The demonstrated filter is designed at 12 GHz with less than 3.2 dB insertion loss for a 250-MHz bandwidth, and the minimum insertion loss is 1.5 dB. It presents low insertion loss, high power capacity in planar compact configuration with a standard PCB fabrication process.     

基于改进PSO-BP神经网络的冰蓄冷空调冷负荷动态预测模型

当前多数冰蓄冷空调冷负荷动态预测方法中,由于模型输入变量与输出结果相关性差、信息冗余度高等原因,导致多数预测模型在预测精度和收敛速度方面都未达到理想的预测效果,因此,提出一种改进的PSO-BP神经网络算法预测大型公共建筑的冷负荷。对于输入变量与输出结果采用灰色关联度分析,消除样本输入变量对数的耦合性,确定影响冰蓄冷空调系统冷负荷的关键性因素,将其作为输入变量,预测冰蓄冷空调系统动态冷负荷。结果表明：T时刻室外空气温度、T-1 h时刻室外空气温度、T时刻室外空气湿度、T时刻太阳辐射强度、T-1 h时刻太阳辐射强度、T-1 h时刻空调冷负荷是影响T时刻冰蓄冷空调系统冷负荷的关键因素,并以此作为预测模型的输入变量。相对于传统PSO-BP神经网络全输入变量预测算法,该模型预测结果精确度更高、收敛速度更快。     

Evaluation of the FEH Rainfall-Runoff Method for Catchments in the UK

The Flood Estimation Handbook, which was published in 1999, has substantially replaced the Flood Studies Report for design flood estimation in the UK. Although there are substantial differences between the handbook and the report, the philosophy of the rainfall-runoff method has been retained in the handbook. However, there are differences in the equations that have been used to estimate parameters of the rainfall-runoff method.
This paper provides a comprehensive evaluation of the performance of the Flood Estimation Handbook rainfall-runoff method for flood-frequency estimation, using data from eighty-eight catchments in the UK. The performance is evaluated by reference to the flood quantiles obtained from single-site frequency analysis, and comparison is made with the performance of the Flood Studies Report methodology. In general terms, the handbook over-estimates flood quantiles, with respect to (a) those estimated from observed records and (b) the report's quantiles. The paper explores the causes of these over-estimations and seeks linkages with particular catchment characteristics.     

高海拔地区典型长空气间隙的操作冲击放电特性和海拔校正

研究棒-板和棒-棒空气间隙等典型的空气间隙的放电特性和海拔校正,不仅可为高海拔地区输变电工程空气间隙距离的选择提供参考,而且可为更高海拔地区空气间隙放电电压的海拔校正提供依据。为此,在海拔高度为0m、2 200m、3 000m、4 300m和5 000m的地区,对不同间隙距离的棒-板和棒-棒典型长空气间隙进行了标准操作冲击放电特性试验。根据试验结果计算分析了不同海拔地区典型的棒-板和棒-棒间隙的操作冲击放电电压的海拔校正因数。将IEC 60071-2标准中规定的放电电压海拔校正方法适用范围外延至海拔高度5 000m,对棒-板间隙的放电电压的海拔校正因数进行了计算。试验结果表明,随着海拔高度的升高,棒-板和棒-棒间隙的操作冲击放电电压都降低,棒-棒间隙放电电压的降低幅度要大于棒-板间隙。根据IEC 60071-2标准对海拔校正因数的计算结果在海拔高度为2 200m的地区与试验结果基本一致;但随着海拔高度的增加,计算结果与试验结果的差别越来越大:在海拔高度为4 300m和5 000m的地区,间隙距离约为2m时,计算结果比试验结果小10%以上。     

Continued development of a mass balance model of chemical fate in a sewage treatment plant

Chemicals that pass through a sewage treatment plant (STP) and into receiving waters lead to exposure of human and ecological receptors. Most countries require that such chemicals and especially those that are new to commerce be assessed for their treatability in STPs using a screening-level model. The STP model has been widely used for such assessments in Canada, the US and elsewhere. It is important for both industry and regulators that such a model be simple, accurate and applicable even with the limited data available for most chemicals. The STP model has been upgraded to include the capability to handle ionizing chemicals, and a variety of treatment plant configurations commonly used in Canada and elsewhere around the world. A scheme for obtaining appropriate biodegradation half-lives for the different treatment options from available aqueous biodegradation half-lives or standard biodegradability tests is suggested. Model simulations show good agreement with pilot-scale experimental data from literature for 20 organic chemicals with widely varying physico-chemical properties.     

Consumer acceptance of reformulated food products: A systematic review and meta-analysis of salt-reduced foods

Food product reformulation is promoted as an effective strategy to reduce population salt intake and address the associated burden of chronic disease. Salt has a number of functions in food processing, including impacting upon physical and sensory properties. Manufacturers must ensure that reformulation of foods to reduce salt does not compromise consumer acceptability.

The aim of this systematic review is to determine to what extent foods can be reduced in salt without detrimental effect on consumer acceptability.

Fifty studies reported on salt reduction, replacement or compensation in processed meats, breads, cheeses, soups, and miscellaneous products. For each product category, levels of salt reduction were collapsed into four groups: <40%, 40–59%, 60–79% and ≥80%. Random effects meta-analyses conducted on salt-reduced products showed that salt could be reduced by approximately 40% in breads [mean change in acceptability for reduction <40% (?0.27, 95% confidence interval (CI) ?0.62, 0.08; p = 0.13)] and approximately 70% in processed meats [mean change in acceptability for reductions 60–69% (?0.18, 95% CI ?0.44, 0.07; p = 0.15)] without significantly impacting consumer acceptability. Results varied for other products.

These results will support manufacturers to make greater reductions in salt when reformulating food products, which in turn will contribute to a healthier food supply.     

高海拔地区直流输电线路鸟粪闪络模拟试验研究

为掌握高海拔地区直流架空输电线路的鸟粪闪络特性,在海拔高度为4 300 m的西藏羊八井高海拔试验基地对直流V串绝缘子的鸟粪闪络问题进行了试验研究。研究表明:中等黏度的鸟粪易于形成连续的鸟粪通道,闪络概率较高,且正极性的鸟粪闪络概率略高于负极性;在1.9～20.9 mS/cm的电导率范围内,鸟粪电导率对鸟粪闪络概率影响很小;增加垂直间隙距离可降低鸟粪闪络概率。基于试验提出了±400k V柴拉直流线路垂直间隙距离推荐值,考虑风偏修正和鸟类泄粪角度的影响,在4 500～5 000 m海拔地区,防护半径宜设置为3.5 m。鸟粪闪络属于空气间隙击穿与沿鸟粪通道沿面放电相结合的混合放电过程,在海拔高度4 300 m处,其间隙最低击穿电位梯度约为2.1 kV/cm,鸟粪与均压环间隙的放电可近似等效为棒–棒间隙。     

Instructional objectives and bench examinations in circuitslaboratories

For a three-course sequence of required circuits laboratories, the author has written detailed instructional objectives. These behaviorally observable goals focus student learning on the educational objectives selected by the course supervisor. They summarize the concepts, relationships, and measurement skills presented in the course. During a bench final examination, the student randomly selects one or more of these instructional objectives and demonstrates mastery to the teaching assistant. This encourages the student to master all instructional objectives in order to succeed in the course     

液压系统的频域模型

本文根据频率特性实验数据,以系统辨识程序为工具,确定了阀控马达试验台的实际频域模型。并介绍了辨识原理,所开发的辨识程序可以确定系统的阶次与结构参数。经实测频率响应和计算机辅助分析结果证明,辨识模型具有较高的准确度。