Contact duration aware evaluation for content dissemination delay in mobile social network

Groups of people with mobile phones using short‐range connections such as WiFi and Bluetooth to propagate messages can be modeled as, with regard to regular absence of end‐to‐end connection, mobile social networks (MSNs), which can be exploited to offload a significant amount of mobile content from the overloaded infrastructure networks such as 3G. The study of content transmission delay for the applications of mobile content dissemination in MSNs is an important problem, because to enhance the network capacity, the traffic is offloaded at the cost of inducing longer delay. In contrast to existing works, which ignore the factors of contact duration limits and large content size, we present a contact duration aware framework to model the content dissemination process in MSNs, give an explicit expression for the average content dissemination delay, and reveals its relationship with various system parameters of content size, users’ selfishness, number of involved subscribers, infecting ratio, and so on. We apply our proposed model to real‐life traces to assess its reliability by comparing the theoretical results with measured statistics and present extensive upshots to evaluate the influence of various parameters on system performance. The results demonstrate the accuracy of our proposed framework and reveal that system parameters of content size, system infecting ratio and intragroup transmission are the most important factors to influence the content dissemination delay. Copyright © 2013 John Wiley & Sons, Ltd.     

Dead‐time elimination SVPWM of six‐leg inverter

We present a six‐leg voltage source inverter (VSI) with a single DC link to feed a three‐phase inductive load. The space vector pulse width modulation (SVPWM) of the six‐leg inverter is studied in detail. The novel switching strategy in one sampling period for H bridge is proposed to avoid the 180° phase shift of the PWM signals for upper and lower side switches. Based on the novel switching strategy, a dead‐time elimination SVPWM is proposed, which can be easily implemented on a digital signal processor. Experimental results are presented to demonstrate the validity and features of the proposed novel SVPWM. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A classification control strategy for energy storage system in microgrid

Storage devices are indispensable elements in a microgrid to compensate for the power imbalance between loads and the distributed generator (DG) output. Different storage strategies give diverse performances in adjustment speed and capacity. Based on the performance of different storage devices and the features of power imbalance curve in different periods, a classification control strategy is proposed in this paper. First, storage devices are given priorities according to the adjusting speed, and the power imbalance curve is divided into two periods according to the changing speed. During an emergency, all the storages are employed to compensate the rapidly increasing power imbalance; during the steady period, storage device with higher priority is employed to track the instantaneous component of power imbalance, while storage device with lower priority is used to replace the kWh output of higher priority storage. The proposed strategy is tested in a microgrid within the subdistribution network of IEEE RBTS Bus6 system using Monte Carlo methods. Simulation results indicate that the classification control strategy could endow the system with fast adjusting ability through coordination between storages. Reliability indices of the testing system are utilized to demonstrate that the classification control strategy could improve the stability of the microgrid and reliability of the distribution network. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

地下室模型对超高层建筑地下室核心筒剪力墙受力影响研究

通过理论分析和实际工程数值计算研究了高层建筑地下室楼板模型及地下室外回填土约束作用对核心筒剪力墙计算结果的影响。研究表明,地下室楼板采用刚性假定不能真实地反映结构的受力状况,无论地下室外回填土的约束作用是否考虑,都会得出地下1层墙肢剪力突增的计算结果;而地下室楼板采用弹性壳元模拟,即便地下室外回填土的约束设定为无约束和水平刚性约束两种极端情况,地下1层核心筒剪力墙依然不会出现显著的剪力突变。     

丁基橡胶铝箔防水卷材的性能研究

介绍了丁基橡胶铝箔防水卷材的配方和生产工艺,讨论了丁基橡胶的用量对卷材产品耐热度、低温柔性及剥离强度的影响。考察了丁基橡胶铝箔防水卷材与改性沥青防水卷材的常规防水指标以及阻燃、保温、隔音等特殊指标的差异,指出丁基橡胶铝箔防水卷材特别适用于屋面工程。     

微观尺度下浇筑式沥青混合料超热老化机理

为了揭示浇筑式沥青混合料超热老化机理,采用傅里叶红外光谱法（FTIR）和热失重法(TG)实时追踪扫描了微观尺度下浇筑式沥青不同超热温度下分子基团以及轻质组分的变化规律,分析了超热温度下挥发和氧化对改性沥青老化的影响进程.结果表明：在超热温度下,挥发对浇筑式沥青混合料老化所起的作用明显,并且一直贯穿整个超热老化过程,而氧气浓度决定了氧化在其整个老化过程中的作用时间,在高氧气浓度下,氧化主要发生在老化前期,而老化后期轻质组分的挥发起主导作用.     

府河随州区段河流水质模拟

通过对湖北省府河随州区段河流现场调查和水质现状监测,应用系统的方法,将河流进行概化,并建立了该河段的一维水质模型,结合2008年的水文资料,应用实测资料进行模型参数的确定。经模型验证,模拟结果与该段河流的实际水质监测结果基本吻合,表明该模型具有一定的合理性和实用性。     

大规格玻璃板在室内装饰中的应用

通过某大厦屋顶花园室内核心筒大规格玻璃装饰板安装施工实例,对大规格玻璃装饰板的安装工艺、质量控制要点等进行了系统分析,阐述了大规格玻璃板在实际安装中的安全性和实用性,以及良好的装饰效果。     

Block adaptive kernel principal component analysis for nonlinear process monitoring

On‐line modeling of multivariate nonlinear system based on multivariate statistical methods has been studied extensively due to its industrial requirements. In order to further improve the modeling efficiency, a fast Block Adaptive Kernel Principal Component Analysis algorithm is proposed. Comparing with the existing work, the proposed algorithm (1) does not rely on iterative computation in the calculating process, (2) combines the up‐ and downdating operations to become a single one (3) and describes the adaptation of the Gram matrix as a series of rank‐1 modification. In addition, (4) the updation of the eigenvalues and eigenvectors is of and high‐precision. The computational complexity analysis and the numerical study show that the derived strategy possesses better ability to model the time‐varying nonlinear variable interrelationships in process monitoring. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4334–4345, 2016