C-RAN架构下一种基于分形定理的载波迁移预测算法

作为C-RAN关键技术之一的实时虚拟化技术要求实现硬件处理资源的虚拟化管理,实现物理资源的动态分配和负载均衡,保证虚拟基站的实时性,处理时延和抖动可控。为提高物理资源的动态分配和负载均衡的效率,在传统虚拟机迁移策略基础上结合分形理论,提出一种动态载波迁移预测算法,避免了因瞬时负载峰值触发载波迁移而带来不必要的迁移开销。该算法通过对物理资源负载离散历史数据进行分形拼贴拟合出完整负载曲线,然后根据分形维度不变性实现对未来数据的预测。为实现对该算法的仿真,结合C-RAN的系统架构搭建了一个基于并行离散事件仿真(parallel discrete event simulation PDES)的验证平台,仿真结果表明该算法能在有效减少虚拟基站迁移次数的同时确保达到负载均衡的目的。     

基于功图的油井动液面计算模型及应用

针对油井动液面实时监测困难和基于地面功图推算误差大的问题,以油井地面示功图为条件,运用一维带阻尼波动方程求解泵功图;并研究了泵功图曲线各点的曲率计算模型、固定阀和游动阀开闭点确定方法以及泵功图上下冲程载荷差的计算方法。结合井筒及环空流体压力分布计算相关式,建立了基于泵功图计算动液面深度的数学模型。经51口油井的计算分析,计算动液面深度与实测动液面深度的最大相对误差为14.84%,最小相对误差为0.48%,平均相对误差为3.61%;相对误差在10%以内的有48口,占计算总井次的94.1%。研究结果表明所建立的计算模型具有较高的精度,能够实现了油井动液面的实时、准确计量,提高了油井生产分析的及时性,有利于油田数字化和信息化建设。     

基于加权余弦相似度与极限学习机的电力负荷短期预测

为提高电力系统管理的效率,提出一种基于加权余弦相似度与极限学习机(extreme tearning machine, ELM)的电力负荷短期预测设计。通过熵权法对电力负荷相关物理信息进行权重分配,获得的权重赋予到余弦相似度中,利用加权余弦相似度对历史日与待测日的电负荷数据进行相似度选取,筛选数据作为极限学习机的输入,提高极限学习机回归模型的精度,最终获取电力负荷预测。实验分析与反向传播BP(back propagation)神经网络、支持向量机(spupport vector machine, SVM)预测算法对比,该方法能有效提高预测模型的精度,同时简化计算量。     

Promoting cooperation in selfish computational grids

In distributed computing, the recent paradigm shift from centrally-owned clusters to organizationally distributed computational grids introduces a number of new challenges in resource management and scheduling. In this work, we study the problem of Selfish Load Balancing which extends the well-known load balancing (LB) problem to scenarios in which each processor is concerned only with the performance of its local jobs. We propose a simple mathematical model for such systems and a novel function for computing the cost of the execution of foreign jobs. Then, we use the game-theoretic framework to analyze the model in order to compute the expected result of LB performed in a grid formed by two clusters. We show that, firstly, LB is a socially-optimal strategy, and secondly, for similarly loaded clusters, it is sufficient to collaborate during longer time periods in order to make LB the dominant strategy for each cluster. However, we show that if we allow clusters to make decisions depending on their current queue length, LB will never be performed. Then, we propose a LB algorithm which balances the load more equitably, even in the presence of overloaded clusters. Our algorithms do not use any external forms of compensation (such as money). The load is balanced only by considering the parameters of execution of jobs. This analysis is assessed experimentally by simulation, involving scenarios with multiple clusters and heterogeneous load.     

新疆某地区电网负荷特性分析

电力负荷是电力系统的重要组成部分之一,也是电能的消耗侧。电力负荷在电力系统的安全稳定与控制中起着重要的作用,因此,在电力系统运行过程中必须考虑负荷对电力系统的影响。近年来随着社会经济的发展,新疆地区的电力负荷的结构发生了巨大的变化,这对新疆电网的安全运行和控制带来了一定的影响。该文对负荷特性的国内外研究现状进行了概述,介绍了负荷特性分析的几种技术指标,最后根据新疆某地区电力负荷的历史数据,进行了负荷特性分析。     

利用铁电存储器实现ADSP-BF535的SPI加载

在数字信号处理(DSP)系统上运行的程序,在系统上电复位后需要加载到DSP的存储空间上,这是从事DSP系统开发不可缺少的环节。基于铁电存储器,提出了利用ADSP-BF535的SPI口进行加载的设计方案。该方案已应用于某雷达数字信号处理系统中。     

英文字幕电影对词汇附带习得的影响

调查英文电影在词汇附带习得中的作用,以语言输入假设和任务投入量假设为理论依据,进行实证研究实验。结果显示：英语学习者在看英文字幕电影时能够附带习得词汇,并且任务中学习者投入量越大,词汇附带习得的效果越好。     

基于多信道无线传输的旋翼载荷测试技术研究

直升机旋翼系统载荷和强度飞行试验是对真实大气环境中旋翼系统应力载荷谱的研究,它提供的真实数据是理论计算所不能提供的。因此旋翼系统载荷试飞是直升机设计定型试飞中极其重要的项目。针对直升机旋翼系统载荷测试技术需求,采用模块化、冗余度和高集成的设计理念,通过多信道无线传输设计等技术,将采集的动态载荷数据调制、发射与解调,实现了多通道、高带宽和精同步的旋翼系统载荷数据采集与监控。该技术对于直升机旋翼系统载荷试飞中遇到的类似问题具有一定的借鉴意义。     

Post-divergence and post-flutter analysis of sub-tangentially loaded and damped Beck column using a nonlinear FE procedure

Both post-divergence and post-flutter behaviors of damped Beck columns subjected to a sub-tangentially follower force are rigorously explored using an exact co-rotational frame element. First a linear stability theory of the damped Beck column is summarized using a stability map. A geometrically nonlinear frame element based on the co-rotational formulation is then formulated including mass matrix, Rayleigh damping matrix, and load-correction stiffness matrix due to circulatory forces. The dynamic FE analysis is performed using Newmark integration method. Finally a Beck column model is parametrically analyzed in order to investigate non-linear stability characteristics of the internally and externally damped non-conservative system. In particular, interesting nonlinear behaviors of Beck column quite different from those predicted by the linear theory are reported through static and dynamic nonlinear analysis with variation of sub-tangentiality of the follower force.     

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ITER测试平台无功补偿及谐波抑制系统包含一套由RLC滤波支路和晶闸管控制电抗器(TCR)组成的无功补偿装置,当接入电网时,为防止系统甩负荷对电网的安全性产生影响,通过计算解析研究分析了系统甩负荷时在110kV母线上产生的过电压。结果表明,当因系统故障进行甩负荷时,母线电压上确实会产生一个较高的过电压,其数值已超出国家标准允许范围,可能会对电网产生一定影响,需采取防护措施,即加入了一条由反并联二极管和电阻组成的旁通支路来释放主回路电流以减少过电压。MATLAB的仿真结果也验证了上述结果的正确性。