Approximations for heavily loaded G/GI/n + GI queues

Motivated by applications to service systems, we develop simple engineering approximation formulas for the steady‐state performance of heavily loaded G/GI/n+GI multiserver queues, which can have non‐Poisson and nonrenewal arrivals and non‐exponential service‐time and patience‐time distributions. The formulas are based on recently established Gaussian many‐server heavy‐traffic limits in the efficiency‐driven (ED) regime, where the traffic intensity is fixed at ρ > 1, but the approximations also apply to systems in the quality‐and‐ED regime, where ρ > 1 but ρ is close to 1. Good performance across a wide range of parameters is obtained by making heuristic refinements, the main one being truncation of the queue length and waiting time approximations to nonnegative values. Simulation experiments show that the proposed approximations are effective for large‐scale queuing systems for a significant range of the traffic intensity ρ and the abandonment rate θ, roughly for ρ > 1.02 and θ > 2.0. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 187–217, 2016     

院校办学绩效集对分析评定

讨论了集对分析方法评定院校办学绩效．作为算例,对军队16所工程技术院校进行了排序,并用主成分分析法进行了验证．     

亚微秒负脉冲高电压击穿的水介质开关特性的实验研究

本文提供了在02装置上进行的水中亚微秒负脉冲高电压击穿的实验研究的结果。击穿场强≥250KV/cm,进行统计性测量。实验研究用的电极材料为不锈钢,尺寸和形状各有不同。     

全垫升式气垫船水压场数值模拟

提出了任意分布的气垫压力所产生的水压场的计算方法 ,对椭圆域上均匀分布的气垫压力产生的水压场进行了数值模拟 ,并将计算结果与实验进行了比较 .结果表明 ,用数值模拟的方法研究全垫升式气垫船水压场是可行的     

压水堆大破口失水事故安全装置实验研究

本文针对压水堆发生主管道“双端断裂”的大破口失水事故而提出了一种安全装置,对其工作原理及工程上实现的可能作了浅析,对其原理性实验过程及结果作了介绍。实验表明:这种安全装置结构简单,原理正确,工程上易实现,造价低廉。它在大破口失水事故发生初期(约数十毫秒)就能充分发挥其作用。对于防止堆芯熔化具有重要意义。     

基于多属性决策方法的防空C3I系统效能评估

介绍了防空C3I系统效能的定义及效能评估的一般处理过程.针对效能指标的多样性,提出了基于多属性决策(MADM)的效能评估方法,并通过一个示例给出MADM方法的处理过程,有效地解决了防空C3I系统效能评估这一复杂而困难的问题,仿真结果证明了方法的可行性.     

大型复合母排多端口电路仿真模型研究

针对阻感负载模型不能精确反映出吸收电容等缓冲器件对复合母排特性影响的问题,提出了复合母排多端口参数矩阵的建模方法。利用该复合母排多端口电路仿真模型,对并联器件的电流不均度以及吸收电容容值对功率器件过电压性能的影响进行了分析,仿真结果可指导复合母排优化设计及吸收电容的选型。通过对逆变器系统的仿真和试验,对比了中点电流的频谱,验证了复合母排多端口电路仿真模型的有效性。     

大规模科学数据体绘制技术综述

体绘制是刻画大规模科学数据中复杂物理特征的有效途径,然而,数据量极大、特征难以捕捉等问题依然是目前体绘制研究的主要挑战。为此,研究者们从三个方面对体绘制算法进行了深入研究,以提高大规模数据体绘制的效率和效果。一方面,依托硬件通过多处理器核来分担计算,降低单处理器核所要完成的计算量,是提高体绘制效率的一个有效途径。另一方面,充分发掘数据场内在特性对三维数据场进行约简,大幅减少绘制处理数据量从而降低算法开销,也是提高体绘制效率的一个有效途径。同时,在体绘制算法中融入特征分析和特征增强方法,让复杂物理特征从数据场中突显出来,以实现对科学数据的高质量绘制。本文对国内外体绘制技术相关研究进展进行了调研、综述,并分析了不同的研究方法,最后展望了未来体绘制技术研究的可能发展方向,包括应用驱动的特征体绘制、基于特征的约简体绘制、适应硬件的体绘制多级加速以及原位智能化体绘制等。     

A guarantee rate optimization model for wastewater treatment system design under uncertainty

We consider a design problem for wastewater treatment systems that considers uncertainty in pollutant concentration levels at water sources. The goal is to optimize the selection of treatment technologies and pipeline connections, so that treated wastewater can achieve specified effluents discharge limits as well as possible. We propose a new two-stage model to optimize a set of guarantee levels, that is, the maximum concentration level of source pollutants for which treated wastewater can be compliant with discharge limits. In the first stage, treatment technologies and pipeline connections are selected. In the second stage, when pollutant concentration levels are revealed, wastewater distribution and mixing are determined. A key attractiveness of the proposed guarantee rate optimization model is that it can be simplified into a single-stage mixed-integer linear program. In our numerical experiments based on real-world pollutants data, the guarantee rate model demonstrates its advantages in terms of computational efficiency, scalability and solution quality, compared with the standard probability maximization model. Finally, the methodology proposed in this paper can also be applied to other two-stage problems under uncertainty with similar uncertainty characteristics.     

利用期间核查确定测量设备校准间隔

按照预定的日程实施测量设备再校准,是实验室一个通用的做法,ISO／IEC17025《检测和校准实验室能力的通用要求》要求,在测量过程中应按照经济合理的日程插入期间核查,以证实测量设备是否处于校准技术状态。本文打破以时间周期确定测量设备校准间隔的传统模式,探讨以测量设备测量被测对象的多少（即测量设备使用的频繁程度）为基础,利用期间核查实时发现测量设备校准技术状态的变化,从而确定测量设备校准间隔的新模式。