串联法氧化铝生产中的合流脱硅

合流脱硅是简化联合法生产流程、降低能耗的有效措施。因此。国内外业界做了大量卓有成效的工作。串联法的工艺特点，更宜于采用合流脱硅。试验结果表明，串联法采用常压合流脱硅流程可以达到所需要的硅量指数。文中还对合流脱硅的硅量指数、合流点、合流脱硅温度、赤泥种子和添加石灰乳等问题进行了讨论。     

Model checking response times in Networked Automation Systems using jitter bounds

Response time (RT) of Networked Automation Systems (NAS) is affected by timing imperfections induced due to the network, computing and hardware components. Guaranteeing RT in the presence of such timing imperfections is essential for building dependable NAS, and to avoid costly upgrades after deployment in industries.This investigation proposes a methodology and work-flow that combines modelling, simulation, verification, experiments, and software tools to verify the RT of the NAS during the design, rather than after deployment. The RT evaluation work-flow has three phases: model building, modelling and verification. During the model building phase component reaction times are specified and their timing performance is measured by combining experiments with simulation. During the modelling phase, component based mathematical models that capture the network architecture and inter-connection are proposed. Composition of the component models gives the NAS model required for studying the RT performance on system level. Finally, in the verification step, the NAS formal models are abstracted as UPPAAL timed automata with their timing interfaces. To model timing interfaces, the action patterns, and their timing wrapper are proposed. The formal model of high level of abstraction is used to verify the total response time of the NAS where the reactions to be verified are specified using a subset of timed computation tree logic (TCTL) in UPPAAL model checker. The proposed approach is illustrated on an industrial steam boiler deployment.     

A sliding window technique for interactive high-performance computing scenarios

Interactive high-performance computing is doubtlessly beneficial for many computational science and engineering applications whenever simulation results should be visually processed in real time, i.e. during the computation process. Nevertheless, interactive HPC entails a lot of new challenges that have to be solved – one of them addressing the fast and efficient data transfer between a simulation back end and visualisation front end, as several gigabytes of data per second are nothing unusual for a simulation running on some (hundred) thousand cores. Here, a new approach based on a sliding window technique is introduced that copes with any bandwidth limitations and allows users to study both large and small scale effects of the simulation results in an interactive fashion.     

高效动态存储再分配方案与实现

为提高大小和数量都不确定的数据动态存储的空间利用率和处理速度,针对常规系统动态存储分配存在的问题,提出一种高效的动态存储再分配方案。通过减少系统动态存储分配的执行次数,在有效提高存储空间利用率的同时,提高存储空间动态分配的速度,给出动态存储再分配方案的具体实现算法,用实际数据对其性能进行测试。测试结果表明,该方案能节省36％至75％的系统存储空间,分配速度提高了20至50倍。     

数据中心网络TCP Incast仿真分析

为分析云计算数据中心网络中的TCP Incast问题的产生原因并探讨缓解该问题的有效途径,采用基于NS2仿真实验的方法,通过改变TCP协议类型、交换机缓冲区大小、服务请求单元大小及重传超时RTO值等影响因素,分析传输吞吐率性能的变化。分析结果表明,通过改变这些影响因素有助于缓解TCP Incast问题,但同时也存在各种缺点和局限性。     

基于高能效及公平性的移动设备定位算法

通过分析校园师生基于GPS的真实活动轨迹,以及何种算法才最适合具有自私性的移动用户展开合作,提出一种高能效及用户公平定位技术.通过采用代理设备合作思想,提出一种集中式最优算法,在保证固定精度界限和设备公平的基础上,实现移动设备GPS时间平均功率最小化.通过控制退避时间和GPS关闭时间,提出一种分布式准最优算法.最后,基于多种拓扑结构进行全面的仿真实验,验证了算法的高能效性和公平性.     

基于Feeds的社交网络活跃度分析

从用户产生和消费Feeds的角度分析社交网络变得不活跃的原因,通过分析人人网某大学社区用户长周期的Feeds行为来探讨该社区用户活跃度的变化。通过对用户活跃性周期和Feeds时间间隔的分析,发现越来越多的用户产生Feeds的活跃度在下降,并导致其他用户接收到的信息流的流速和多样性下降。社交网络用户由于各种原因离开或变得不活跃,并通过信息流对其朋友圈形成负向反馈,这可能是社交网络变得不活跃的深层原因。模拟实验表明,30%的初始不活跃用户会使得整个社区的信息流快速下降,并导致整个社区不活跃。     

利用曲线拟合对触觉数据的压缩

为减轻离线触觉数据压缩带来的失真变形,提出利用曲线拟合的压缩方法.在假定触觉数据所对应原触觉信号能用分段二次参数曲线表示的前提下,通过反向采样过程来构造触觉数据拟合曲线,该曲线由分段二次曲线组成,在连接处达到切线连续,且每段二次曲线对原触觉信号具有二次多项式逼近精度.为避免保存拟合曲线的所有系数以进一步提高数据减少率,对拟合曲线系数进行了迭代求解,从而只需编码保存部分系数即可解码.实验结果表明,该方法在保持高数据减少率的前提下减轻了压缩失真变形.     

Performance comparison of reduced models for leak detection in water distribution networks

This paper presents a methodology for comparing the performance of model-reduction strategies to be used with a diagnostic methodology for leak detection in water distribution networks. The goal is to find reduction strategies that are suitable for error-domain model falsification, a model based data interpretation methodology. Twelve reduction strategies are derived from five strategy categories. Categories differ according to the manner in which nodes are selected for deletion. A node is selected for deletion according to: (1) the diameter of the pipes; (2) the number of pipes linked to a node; (3) the angle of the pipes in the case of two-pipe nodes; (4) the distribution of the water demand; and, (5) a pair-wise combination of some categories.The methodology is illustrated using part of a real network. Performance is evaluated first by judging the equivalency of the reduced network with the initial network (before the application of any reduction procedure) and secondly, by assessing the compatibility with the diagnostic methodology. The results show that for each reduction strategy the equivalency of networks is verified. Computational time can be reduced to less than 20% of the non-reduced network in the best case. Results of diagnostic performance show that the performance decreases when using reduced networks. The reduction strategy with the best diagnostic performance is that based on the angle of two-pipe nodes, with an angle threshold of 165°. In addition, the sensitivity of the performance of the reduced networks to variation in leak intensity is evaluated. Results show that the reduction strategies where the number of nodes is significantly reduced are the most sensitive.Finally this paper describes a Pareto analysis that is used to select the reduction strategy that is a good compromise between reduction of computational time and performance of the diagnosis. In this context, the extension strategy is the most attractive.