全IP电视直播节目的即时回看技术

介绍了已运用于实践中的一种全IP电视直播节目即时回看技术,用户通过遥控器一键实现直播节目的即时回看,极大地提升了用户的观看体验。通过在临汾市智慧广电全IP融合业务网建设实践项目中的使用,技术的先进性和有效性得到实践验证。     

MooseFS热备元数据节点设计与实现

针对MooseFS元数据节点的单点故障问题，对MooseFS源码进行改造，为其增加一个热备的备元数据节点，并通过主备之间同步元数据，备节点回放操作日志等技术使得备元数据节点内存中的元数据时刻跟主元数据节点保持一致。当主元数据节点发生故障切换到备元数据节点后，备元数据节点无需从本地加载元数据即可快速接替主元数据节点对外提供服务。测试结果表明，备元数据节点本地和内存中的元数据均与主元数据节点保持一致，且故障恢复时间小于1 s。     

Prediction of sediment,particulate nutrient and dissolved nutrient concentrations in a dry tropical river to provide input to a mechanistic coastal water quality model

A Generalised Additive Modelling (GAM) approach is applied to prediction of both particulate and dissolved nutrient concentrations in a wet-tropical river (the Fitzroy River, Queensland, Australia). In addition to covariant terms considered in previous work (i.e. flow, discounted flow and a rising-falling limb term), we considered several new potential covariates: meteorological and hydrological variables that are routinely monitored, available in near-real time, and were considered to have potential predictive power. Of the additional terms considered, only flows from three tributaries of the Fitzroy River (namely, the Nogoa, Comet and Isaac Rivers) were found to significantly improve the model. Inclusion of one or more of these additional flow terms greatly improved results for dissolved nitrogen and dissolved phosphorus concentrations, which were not otherwise amenable to prediction. In particular, the Nogoa sub-catchment, dominated by pasture for cattle, was found to be important in determining dissolved inorganic nitrogen and phosphorus concentrations reaching the river mouth. This insight may direct further research, including future refinement of processed-based catchment models. The GAMs described here are used to provide near real-time river boundary conditions for a complex coupled hydrodynamic and biogeochemical model of the Great Barrier Reef Lagoon, and can be coupled with a forecasting hydrological model to allow integrated forecasting simulations of the catchment to coast system.     

基于确定性测量矩阵与变阈值SAMP的超高次谐波检测算法

随着电网中采用高频电力电子器件制造的设备逐渐增多,配电网中的超高次谐波现象已经成为了一种亟需解决的新型电能质量问题。相较于传统谐波检测方法采样超高次谐波信号时产生的巨大数据量,压缩感知作为一种新型信号处理方法,在使用测量矩阵对稀疏信号进行亚采样后通过重构算法用较少的数据就能精确地恢复原始信号,有效降低了对采样端硬件的要求。提出了一种基于确定性测量矩阵与变阈值SAMP算法的压缩感知超高次谐波检测算法。首先该方法采用了一种由确定性随机序列构造的测量矩阵,这种确定性测量矩阵的结构与随机测量矩阵相比更易于传输与存储,同时具有和高斯随机矩阵相同的重构性能。其次,针对SAMP重构算法在频谱泄露时易发生稀疏度过估计的问题,提出了一种改进的变阈值SAMP算法,设置一个动态的阈值来控制算法中内积的选取,减少迭代中的误选。改进算法提高了超高次谐波检测的精度,降低了因频谱泄露和噪声造成的误差且更容易硬件实现。最后,通过仿真和实测结果证明了改进算法的准确性和有效性。     

基于确定性解法的新能源微电网经济运行优化

针对典型的微电网应用场景,研究光伏发电、风力发电测和负荷预测误差的数学规律,在考虑微电网环保性因素、经济性因素的基础上,构建基于确定性解法的微电网经济运行优化模型,该模型简化了多目标问题的求解难度。在具体算例中,分析不同置信度、不同预测误差及不同环保算子对微电网经济运行的影响。研究结果表明：提高光伏出力、风电出力和负荷预测精度可以降低微电网优化运行成本;微电网优化运行模型求解时,确定性解法的算法收敛速度快,迭代时间更短。     

Deterministic models for assessing productivity and cost of bored piles

The assessment process of productivity and cost of bored pile construction is dictated by unseen subsurface obstacles, lack of contractor experience and site planning. These problems complicate the estimator's role in evaluating pile equipment productivity and cost. Current research discusses the assessment of piling process productivity and cost using the deterministic technique. Data are collected through questionnaires, site interviews and telephone calls to experts in various construction companies. Many variables have been considered in the piling construction process, such as pile size, depth, pouring method, soil type and construction method. Five deterministic models have been designated to assess productivity, cycle time and cost. The developed models are validated whereas 79% of the outputs have been predicted with more than 75% accuracy. Consequently, three sets of charts have been developed to provide the decision‐maker with a solid planning, scheduling and control tool for piling projects. If a pile has 60′ depth with φ‐18 (18″ diameter pile) in clay soil using a 5′ auger height, the cycle time is estimated as 56 and 65.5 minutes; however, productivity is 6 and 5 holes/day for dry and wet methods, respectively.     

精细搜索策略应用于质量交换网络综合

质量交换网络是化工过程系统的重要组成部分,其优化设计对降低污染排放具有重要意义。采用启发式算法优化质量交换网络时,存在难以兼顾全局搜索和局部搜索的问题。通过分析不同精度优化参数下的优化结果,揭示了该问题的成因,并提出一种精细搜索策略用于基础算法所得结构的深度优化。该策略包含两种方法,方法1采用具有个体回代与分化的高精度强制进化随机游走算法,可保留个体结构变异能力;方法2采用确定性方法依次对多维目标函数中的每个变量进行一维搜索,具有精度高收敛快的优点。将该策略应用于焦炉气脱硫和空气除氨算例,得到的结果分别为407308 USD·a^-1和127807 USD·a^-1,经济性优于现有文献中的结果,验证了本策略的有效性。     

LINGUISTIC FUZZY SYSTEMS AND THEIR APPLICATIONS IN ECONOMETRICS

This paper gives a brief summary of the linguistic fuzzy systems iheory and describes its possible application in econometric modelling. The essential feature of the used approach is a transformation of if-then rale bases into approximative deterministic behavior functions of considered economic systems.     

Experimental Validation of Reaction Rate Distributions for a SVEA-96+ BWR Assembly with Hafnium Control Blades

The accurate estimation of reactor physics parameters related to the presence of cruciform absorber blades in boiling water reactors (BWRs) is important for safety assessment and for achieving flexible operation during the cycle. Characteristics that are affected significantly include distributions of the total fission (F_tot) and ²³⁸Ucapture (C₈) rates for controlled regions. Representative experimental investigations have been performed in the framework of the LWR-PROTEUS programme. In particular, the LWRPROTEUS I-2A experiments concerned the neutronics characterisation of a SVEA-96+ BWR assembly controlled with a hafnium (Hf) blade under full-density water moderation conditions. The current paper presents the comparisons of the measured F_tot and C₈ pin-wise distributions with a variety of stochastic and deterministic calculations: (a) MCNPX2.5 using recent nuclear data libraries (JEFF-3.1, ENDF/BVI. 8, and JENDL-3.3), (b) PHOENIX4 using ENDF/B-VI.3, (c) BOXER using JEF-1, (d) CASMO₄ using JEF-2.2, and (e) HELIOS1.6 using ENDF/B-VI.1. The calculation/experiment comparisons show standard deviations from 1.2% (MCNPX2.5) up to 1.9% (BOXER) for the prediction of the F_tot distribution, the highest individual discrepancy (7.6% with BOXER) being seen close to the “Hf-vertex.” The C₈ comparisons show systematically better agreement than those of F_tot, the lowest standard deviations being 1.0% (BOXER) and the highest only 1.4% (HELIOS). In addition, sensitivity studies highlight the greater importance of modelling aspects, compared with that of nuclear data libraries, for the achievement of satisfactory and validated F_tot and C₈ predictions.     

基于确定性抽样的过冷沸腾边界条件不确定性分析

本文使用Fluent软件构建数学物理模型，对DEBORA过冷沸腾基准实验进行了数值模拟，并采用确定性抽样方法对模拟沸腾流动的边界条件不确定性进行分析，计算得到了主要径向参数分布的期望值和置信区间，分析了边界条件不确定性的影响趋势。此外，还计算得到了不确定性源对部分径向参数的影响权重。结果表明，流体入口温度和壁面热流密度的不确定性对径向空泡份额的影响较大，而运行压力和流体入口温度的不确定性是影响径向液体温度计算的主要因素。