Investigation of Probability Generating Function in an Interdependent <i>M/M/</i>1:(∞;GD) Queueing Model with Controllable Arrival Rates Using Rouche’s Theorem

Present paper deals a M/M/1:(∞;GD) queueing model with interdependent controllable arrival and service rates where- in customers arrive in the system according to poisson distribution with two different arrivals rates-slower and faster as per controllable arrival policy. Keeping in view the general trend of interdependent arrival and service processes, it is presumed that random variables of arrival and service processes follow a bivariate poisson distribution and the server provides his services under general discipline of service rule in an infinitely large waiting space. In this paper, our central attention is to explore the probability generating functions using Rouche’s theorem in both cases of slower and faster arrival rates of the queueing model taken into consideration;which may be helpful for mathematicians and researchers for establishing significant performance measures of the model. Moreover, for the purpose of high-lighting the application aspect of our investigated result, very recently Maurya [1] has derived successfully the expected busy periods of the server in both cases of slower and faster arrival rates, which have also been presented by the end of this paper.

Exploiting Virtual Elasticity of Production Systems for Respecting OTD-Part 1: Post-Optimality Conditions for Ergodic Order Arrivals in Fixed Capacity Regimes

Respecting the on-time-delivery (OTD) for manufacturing orders is mandatory. This depends, however, on the probability distribution of incoming order rate. The case of non-equal distribution, such as aggregated arrivals, may compromise the observance of on-time supplies for some orders. The purpose of this paper is to evaluate the conditions of post-optimality for stochastic order rate governed production systems in order to observe OTD. Instead of a heuristic or a simulative exploration, a Cartesian-based approach is applied to developing the necessary and sufficient mathematical condition to solve the problem statement. The research result demonstrates that increasing speed of throughput reveals a latent capacity, which allows arrival orders above capacity limits to be backlog-buffered and rescheduled for OTD, exploiting the virtual manufacturing elasticity inherent to all production systems to increase OTD reliability of non JIT-based production systems.

基于多队列的机场旅客安检流程仿真研究

为改善机场旅客安检现状,在不改变安检物理格局的前提下,结合排队论提出6种安检验证服务台的排队方式。根据某机场的安检布局及空间尺寸,在以社会力模型为基础的AnyLogic软件中,构建机场旅客安检流程模型。按照低、中、高峰时段的旅客到达率402、623、802人/h对6种排队方式进行仿真,得到安检总时间、平均单队列人数、旅客平均等待时间和安检平均服务时间4个性能指标用来衡量安检效率,发现1对1型且验证服务台远离安检通道的排队方式表现效果更好。再对比验证服务台远离安检通道1~20 m,每隔1 m放置时的性能指标,结果表明:1对1型且验证服务台远离安检通道20 m,队列为S形的排队方式更适用于目前机场旅客安检的需求。

二维片状相对论电子束到靶规律研究

相对论电子束在理想顺磁环境下能够以较高的注量率击中靶目标,但实际情况中由于受环境的影响,相对论电子束的传输方向可能会与地磁场呈小角度偏差,因此会受到地磁场的作用产生拉莫尔进动,影响电子束的到靶瞄准以及到靶注量。基于二维片状相对论电子束,分别对相对论电子束顺磁和偏离磁场3°角两种传输情况进行仿真模拟,通过模拟束团的传输过程,分析研究了顺磁环境下不同传输距离束团到靶率的变化规律,以及偏离磁场3°角时传输过程中注量率的变化规律,为相对论电子束到靶率的预估和靶目标的瞄准提供数据参考。

基于护理团队配合的应急代码模式在院内心搏骤停病人急救中的应用

目的:探讨应急代码模式下护士快速反应和明确角色分工配合院内心搏骤停病人抢救中的应用效果。方法:回顾性分析2020年1月—2021年11月医院收治的70例心搏骤停病人,根据是否采用应急代码进行院内心搏骤停救治分为对照组和观察组,每组35例。比较两组病人复苏成功率、支援人员到位时间、首次除颤时间、静脉通路建立时间、首次给药时间,以及干预前后护士工作压力及抢救医生对护士满意度的差异。结果:医院院内病人心搏骤停复苏成功率由11.4%上升至22.8%;支援人员到位时间由(10.06±1.56)min缩短至(1.68±0.47)min(P<0.05),首次除颤时间、静脉通道建立时间、首次给药时间均较对照组明显缩短(P<0.05);护士工作压力减轻,抢救医生对护士满意度明显提高(P<0.05)。结论:采取应急代码模式能有效缩短心搏骤停急救时支援人员到位时间,明确参加抢救护士的角色和职责,促进心搏骤停病人的有效复苏,提高了医生满意度。

呼鄂城际新机场站站型规模比选研究

新机场站为呼鄂城际新建中间站,其作为地区城际铁路、城市轨道交通、高速铁路及高速公路等多方式综合交通枢纽中心节点,经济合理确定新机场站站型,满足枢纽铁路运输需求,对助力新机场打造综合交通枢纽及发挥车站能力意义重大。首先,对新机场站承担的客运量进行了预测,在此基础上,进一步分析新机场站高峰小时旅客发送量及车站作业量;其次,结合机场站办理的客车对数,针对车站站型规模共研究了2台夹4线(方案Ⅰ)、2岛4线(方案Ⅱ)、2台5线(方案Ⅲ)及2台6线(方案Ⅳ)4个方案,重点从运输组织、到发线能力利用率、工程投资、实施条件、对机场在建工程的影响等方面进行比选;最后,通过高峰小时能力适应性分析检算了车站规模的合理性。研究结果可为后续类似于综合交通枢纽站设置高速铁路地下车站工程提供一定的借鉴意义。

Effect of Substrate Bias on Microstructures of Zirconia Thin Films Deposited by Cathodic Vacuum Arc

Zirconium oxide （Zr02） thin films are deposited at room temperature by cathodic arc at substrate biases of 0 V, -60 V and -120 V, respectively. The crystal structure, composition, morphology, and deposition rate of the as-deposited thin films are systematically investigated by x-ray diffraction, x-ray photoelectron spectroscopy （XPS） as well as scanning electron microscopy. The results show that the crystal structure, morphology and deposition rate of the films all are dependant on substrate bias. With the increase of bias voltage from 0 V to -120 V, the zirconium oxide thin film grown on silicon wafer first exhibits monoclinic lattice and tetragonal lattice, further evolves monoclinic phase with the preferred orientation along the （-111） and （-222） directions at -60 V and finally along nearly one observed preferred （002） direction under -120 V. In addition, the variations of morphology with bias voltage are correlated to changes of the film structure. The results of XPS demonstrate that Zr elements are almost oxidized completely in the films achieved under -120 V bias.

Exploiting Virtual Elasticity of Manufacturing Systems to Respect OTD—Part 2: Post-Optimality Conditions for the Cases of Ergodic and Non-Ergodic Order Rate with Deterministic Product-Mix

Respecting the on-time delivery (OTD) for manufacturing orders is mandatory. However, for non-JIT Batch & Queue Push-manufacturing systems, the compliance of OTD is not intrinsically guaranteed. As an OTD related manufacturing theory is largely missing it is crucial to understand and formalize the necessary conditions of OTD compliance for complex production environments for maximum exploitation of the production capacity. This paper evaluates the conditions of post-optimality while being OTD compliant for production systems, which are characterized by stochastic order rate and a deterministic product-mix. Instead of applying discrete event simulation to explore the real case-by-case order scheduling optimization for OTD compliance, a Cartesian approach is followed. This enables to define theoretically the solution space of order backlog for OTD, which contributes to developing further manufacturing theory. At the base stands the recently defined new concept of virtual manufacturing elasticity by reducing lead-time to increase virtually production capacity. The result has led to defining additional two corollaries to the OTD theorem, which sets up basic OTD theory. Apart from defining the post-optimal requirements to guarantee for orders at least a weak solution for OTD compliance, this paper reveals that for a deterministic product-mix a non-ergodic order arrival rate can be rescheduled into an ergodic order input rate to the shopfloor if the virtual elasticity T is large enough, hence the importance of having fast and flexible production lines.

Measuring ground deformations caused by 2015 Mw7.8 Nepal earthquake using high-rate GPS data

The April 25, 2015 Mw7.8 Nepal earthquake was successfully recorded by Crustal Movement Observation Network of China （CMONOC） and Nepal Geodetic Array （NGA）. We processed the high-rate GPS data （1 Hz and 5 Hz） by using relative kinematic positioning and derived dynamic ground motions caused by this large earthquake. The dynamic displacements time series clearly indicated the displacement amplitude of each station was related to the rupture directivity. The stations which located in the di- rection of rupture propagation had larger displacement amplitudes than others. Also dynamic ground displacement exceeding 5 cm was detected by the GPS station that was 2000 km away from the epicenter. Permanent coseismic displacements were resolved from the near-field high-rate GPS stations with wavelet decomposition-reconstruction method and P-wave arrivals were also detected with S transform method. The results of this study can be used for earthquake rupture process and Earthquake Early Warning studies.

基于持续到达信号强度的辐射源定位方法

为了提高辐射源的定位精度,提出了一种基于持续到达信号强度的定位方法。通过在特定区域内随机分布5个以上观测点,在其观测点持续监测信号源频率的电磁波信号强度,根据监测到的每个观测点的信号强度和持续时间,以及电磁波在自由空间中传输的距离与损耗的关系,采用多元线性回归的方法推算出辐射源的三维坐标完成辐射源定位。结果表明,观测点位置误差和各观测点监测时间误差是降低发现目标的成功率和精度的主要因素;观测点的测量误差对定位成功率和定位精度的影响较小;增加监测点数量可明显提高定位成功率和定位精度,但会增加成本;增加持续监测的时间可在监测点数量较少的情况下,有效抵消位置误差、时间误差对定位成功率和定位精度产生的影响,达到比增加测点数更好的效果。所提辐射源定位方法可在不增加硬件成本的基础上,以降低实时性为代价,大幅度提高定位成功率和定位精度,可适用于对实时性要求较低的电磁辐射源定位场景。

基于元胞自动机的定向车道服务水平分析模型

为了深入了解定向车道这种新型组织方式的应用效果,选取交通流密度、出口拥堵指数、入口变道行为、变道车辆生成率为影响因素,以到车率、平均车速为评价指标,构建元胞自动机仿真分析模型。仿真结果表明,定向车道在高峰时段具有一定的优化作用,但其他情况下优化效果有限,且交通流密度和出口拥堵指数越大时,其服务水平越低。同时,高交通流密度下停车变道和低速变道对服务水平的影响依旧大于常规变道,且不随密度增大向常规变道方案靠近,表明高交通流密度对此类驾驶员的驾驶行为影响较小。常规变道和低速变道条件下,变道车辆的增多对到车率影响较小,而停车变道条件下,到车率会随着变道车辆的增多而降低。

具有工作量D-策略不可靠修理设备和不中断休假的M^(λ_(1),λ_(2))=G=1排队的可靠性

本文研究在基于服务员工作量的D-策略控制下具有可变到达率和不中断单重休假M^(λ_(1),λ_(2))/G/1可修排队模型,其中修理设备在修理故障服务台期间可发生失效且可更换.当服务员休假结束归来时,如果服务员对系统中等待服务的顾客所需服务的总工作量不小于事先设置的工作量阀值D(D≥0),服务员就立即开始服务.运用更新过程理论、全概率分解技术和拉普拉斯变换工具,分别讨论了服务台和修理设备的瞬态不可用度和稳态不可用度、(0,t]时间内的平均故障次数和稳态故障频度这一系列可靠性指标.

面向单基地MIMO雷达的展开增广互质阵设计:低互耦和高自由度

针对现有多输入多输出(multiple input multiple output, MIMO)雷达互耦率高、自由度低的问题,提出了一种低互耦率、高自由度的展开增广互质阵MIMO雷达设计方式。首先在收发两端分别部署展开增广互质阵列。然后通过引入稀疏扩展因子,使展开增广互质阵列子阵的阵元间隔得到扩展,并得到所提出的展开增广互质MIMO雷达阵元位置的闭式表达式。随后通过广义和差联合阵列的概念,详细推导出了雷达的连续自由度和总自由度的闭式解。最后通过基于空间平滑的多重信号分类方法得到波达方向(direction of arrival, DOA)估计。与其他互质MIMO雷达结构相比,所提出的展开增广互质MIMO雷达能够获得更多的连续自由度并具有更低的互耦率。仿真结果验证了所提出的雷达结构在DOA估计方面的有效性和优势。

THE EFFECTS OF MARKET DEPTH ON THE ARRIVAL RATE OF ORDERS

This paper presents a model to describe the dynamic trading process in limit order book.By studying the dynamic pattern of execution probabilities of limit orders with both time and the depth of limit order book,the authors conclude with the following properties:Arrival rates of market buy orders increase as the depth of buy queue in the book increases and decrease as the depth of sell queue increases,and vice versa;similar regularities for the arrival rate of market sell orders;both the arrival rate of market buy order and market sell orders increase as the depth of both sides in the book increases by the same amount.Furthermore,the authors describe more detailed temporary and permanent effects of the market depth on the arrival rates of orders.

考虑乘客异质性的公交运行模型仿真研究

随着中国人口结构的改变,老年人出行占比越来越大,深入研究老年人乘坐公交对于公交系统所产生的影响还比较少。考虑乘客的异质性,将乘客分为两类:老年乘客与普通乘客,通过引入三个控制参数p、q、r分别调整乘客到站总需求、老年人上下车所需时间、老年人在系统中占比,并采用仿真方法对公交系统运行过程进行仿真研究。设计仿真算法时考虑了串车和超车现象的识别以及公交车跨越时间段运行的判别。通过改变三个参数数值使得系统处于不同的仿真条件,并从车头时距偏离程度、公交载客量、系统串车超车情况三个方面对比了系统运行情况。研究发现,乘客到达率是影响系统运行可靠性的关键参数,老年乘客上下车时间和老年人占比的影响作用次之。研究结果可以为公交系统运行管理和相关政策的制定提供参考依据。

南海海岛自动气象站数据双通道传输系统设计与实现

为解决海南省南沙区无人海岛自动气象站单一GPRS数据上传通道数据到报率不高的问题,文章利用北斗卫星通信的优势,首先在硬件上增加基于北斗卫星的通信终端机和配套的供电系统实现海岛站GPRS和北斗通信双通道并行运行;其次将每个通道定义为1个逻辑站点,2个逻辑站点组成1个观测系统,上传1份数据报文,通过本地终端实现观测数据的本地化应用。文章同时分析了改造前后数据到报率等情况,所得结论可以进一步提升岛礁防灾减灾水平。

长江干流寸滩断面污染负荷核算及来源分析

将长江干流寸滩断面以上区域划分为39个排污单元,将河道划分为63个纳污河段,建立排污单元与纳污河段之间的排污-纳污拓扑关系,并基于污染物的产生-入河-降减过程进行断面污染物通量核算.采用输出系数法核算排污单元内各类污染源的产生量,并考虑降水作用,建立污染源入河系数公式,核算排污单元点源与非点源的入河量;考虑污染物在河道内的综合降解过程,核算各纳污节点到输出断面的流达率,分析各纳污节点各类污染源对下游断面的贡献率.通过以上模式对长江干流寸滩断面2004与2005年的污染物通量进行核算,并进行各支流的贡献率分析.核算结果显示:寸滩断面CODMn和TP月通量模拟值与实测值曲线基本吻合,TN月通量模拟值与实测值曲线拟合稍差,整体偏低,可能是忽略了大气沉降的影响所致.从CODMn的贡献率核定结果可以看出,嘉陵江对寸滩断面的贡献率最小,综合贡献率为14%左右,其中点源贡献率为6%左右,非点源贡献率为8%左右,非点源与点源的比率仅为1.3;金沙江对寸滩断面的贡献率最大,综合贡献率达到49%左右,其中点源贡献率为14%左右,非点源贡献率为35%左右,非点源与点源的比率达到2.5,是流域污染控制的重点.

公交停靠站对基本路段通行能力影响

通过对北京市快速路、主干路与次干路的基本路段上的14处港湾式公交停靠站和7处非港湾式停靠站的调查与分析,定量地探讨了公交停靠站对路段通行能力的影响,提出了公交影响时间的概念,建立了2种停靠类型的公交到达频率与公交影响时间关系模型,进而得到公交到达频率与停靠站处路段通行能力的关系模型,最后采用仿真的方法对模型进行了验证.研究结果表明,利用公交到达频率和影响时间来描述停靠站处路段通行能力,更能反映北京实际情况且便于实际应用.

输入排队Crossbar架构下的流量模型

本文基于IP包在路由器各端口到达流量的统计特性,建立了输入排队Crossbar架构下的流量模型,对IP包流量的平均到达速率、突发性和均衡性等流量特征进行了分类定义,给出了各自的充要条件.文中所讨论的突发度B和不均衡度U为到达流量提供了精细的计算粒度,从而为基于IQ-VOQ的调度算法性能评估提供了理论依据.与LAN的自相似模型、WAN的Poisson模型以及数据业务的ON/OFF模型相比,本文讨论的流量模型更适用于基于IQ-VOQ调度算法性能的精确评估,为路由器交换架构的工程设计提供了理论依据.

利用高频GPS进行地表同震位移监测及震相识别

结合日本3.11大地震,利用近震区和远震区若干测站的高频GPS观测数据,采用动态精密单点定位技术分析了强震时复杂的地表运动时序,获得了地表同震位移.在此基础上提出利用S变换对高频GPS地震波进行震相识别,有效拾取了P波初至,反演了P波传播速度并与地震仪数据、USGS提供的参考值进行了对比和分析,为后续地震应急、地震预警提供了重要的、科学的决策依据.