RED的网络性能研究*

在很多网络中, 支持新的拥塞避免机制( 如RED 和ECN) 的节点将会和支持传统丢尾缓存( Drop-Tail) 的节点共存。研究含有两个拥塞节点的混杂网络中TCP 流集的性能, 比较了几种控制算法的数据流公平性, 仿真结果显示采用Adaptive 算法并不能增加数据流的公平性; 仿真也显示混杂网络中单个RED 参数的设置情况会影响整个网络的性能, 具体可以从网络吞吐量、响应时间等判断。RED 的参数设置在双瓶颈情况下再次变得重要, 正如在单瓶颈的情况下一样。     

多元电解质水溶液的值计算法

本文探讨了有关多元电解质水溶液的炯值计算法。提出根据溶液蒸汽压或离子平均活度系数γ±计算二元电解质水溶液(火用)值的公式。多元溶液的(火用)由相同离子强度的二元溶液的(火用)计算。给出海水淡化系统的(火用)数据和脱盐最小功。     

Advancements in the design and validation of an air pollution integrated assessment model for Spain

This paper describes the design and application of the Atmospheric Evaluation and Research Integrated model for Spain (AERIS). Currently, AERIS can provide concentration profiles of NO₂, O₃, SO₂, NH₃, PM, as a response to emission variations of relevant sectors in Spain. Results are calculated using transfer matrices based on an air quality modelling system (AQMS) composed by the WRF (meteorology), SMOKE (emissions) and CMAQ (atmospheric-chemical processes) models. The AERIS outputs were statistically tested against the conventional AQMS and observations, revealing a good agreement in both cases. At the moment, integrated assessment in AERIS focuses only on the link between emissions and concentrations. The quantification of deposition, impacts (health, ecosystems) and costs will be introduced in the future. In conclusion, the main asset of AERIS is its accuracy in predicting air quality outcomes for different scenarios through a simple yet robust modelling framework, avoiding complex programming and long computing times.     

Reconstruction of the rose of directions from a digital microhologram of fibres

Digital holography makes it possible to acquire quickly the interference patterns of objects spread in a volume. The digital processing of the fringes is still too slow to achieve on line analysis of the holograms. We describe a new approach to obtain information on the direction of illuminated objects. The key idea is to avoid reconstruction of the volume followed by classical three-dimensional image processing. The hologram is processed using a global analysis based on autocorrelation. A fundamental property of diffraction patterns leads to an estimate of the mean geometric covariogram of the objects projections. The rose of directions is connected with the mean geometric covariogram through an inverse problem. In the general case, only the two-dimensional rose of the object projections can be reconstructed. The further assumption of unique-size objects gives access with the knowledge of this size to the three-dimensional direction information. An iterative scheme is suggested to reconstruct the three-dimensional rose in this special case. Results are provided on holograms of paper fibres.     

时间序列均值和方差函数的确定方法

发现并提出一个重要定理：时间序列的方差与该序列的差分绝对值序列的趋势项具有相同的函数形式。在此基础上,建立一种确定该差分绝对值序列趋势项的方法,该方法首先采用样本周期图和多点平均对趋势项中的周期项和非周期项进行分离,分别求得其函数表达式,然后再综合得到整个趋势项函数,进而求得原时间序列的方差函数形式,其中待定参数可根据相关系数平稳序列理论求得。该方法也可用于确定时间序列的均值函数(趋势项)。     

接触器铁芯间隙的快速测量

本文介绍了应用单片机和电容传感器技术来检测交流接触器铁芯气隙的快速测量仪。     

Analytical basis for evaluating the effect of unplanned interventions on the effectiveness of a human–robot system

Increasing prevalence of human–robot systems in a variety of applications raises the question of how to design these systems to best leverage the capabilities of humans and robots. In this paper, we address the relationships between reliability, productivity, and risk to humans from human–robot systems operating in a hostile environment. Objectives for maximizing the effectiveness of a human–robot system are presented, which capture these coupled relationships, and reliability parameters are proposed to characterize unplanned interventions between a human and robot. The reliability metrics defined here take on an expanded meaning in which the underlying concept of failure in traditional reliability analysis is replaced by the notion of intervention. In the context of human–robotic systems, an intervention is not only driven by component failures, but includes many other factors that can make a robotic agent to request or a human agent to provide intervention, as we argue in this paper. The effect of unplanned interventions on the effectiveness of human–robot systems is then investigated analytically using traditional reliability analysis. Finally, we discuss the implications of these analytical trends on the design and evaluation of human–robot systems.     

三种疲劳蠕变交互作用寿命预测模型的比较及其应用

对疲劳蠕变交互作用寿命预测方法进行简单回顾,并分别介绍从能量耗竭、韧性耗竭、延性耗竭角度提出的三种应力控制疲劳蠕变寿命预测方法.通过文献试验数据和1.25Cr0.5Mo钢520℃应力控制、梯形波加载试验数据对上述三种模型的优缺点和适用范围进行评价.三种方法的预测精度都大大高于传统的频率分离法和应变能频率分离法;能量模型对应力应变控制模式都适用,延性耗竭模型预测精度最高,平均应变速率模型形式最简单,适用于应力控制下纯蠕变、纯疲劳或疲劳蠕变交互作用下的各种失效组合模式,拓宽了Monkman-Grant经验关系式的应用范围,因此具有重要的工程应用价值和应用前景.最后阐述平均应变速率模型的应用步骤.     

广义时变ARMA模型参数函数的确定方法

提出一种确定广义时变ARMA模型参数函数的方法?该方法首先求得时间序列的均值函数和方差函数,并将广义时变ARMA模型转化为时变ARMA模型,然后通过样本周期图和多点平均方法得到时变参数的函数形式,再分别采用最小二乘法和极大似然法确定其中的待定参数。从而将一个复杂的时变问题转变为相对简单的时不变问题进行处理。     

Two-machine flowshop scheduling to minimize mean flow time under simple linear deterioration

A real industrial production phenomenon, referred to as deteriorating jobs, has drawn increasing attention. However, most research on this issue considers only single-machine problems. Motivated by this limitation, this paper considers a simple linear deterioration model in a two-machine flowshop where the objective is to minimize the mean flow time. Several dominance rules and three lower bounds are proposed to speed up the search for an optimal solution, and several heuristic algorithms are provided to derive near-optimal solutions. In addition, a computational experiment is conducted to evaluate their performances. Results indicate that the algorithms perform well, and a combined heuristic algorithm is recommended for practitioners.