Python Server Page Performance Analysis and Modeling

Today, in the field of computer networks, new services have been developed on the Internet or intranets, including the mail server, database management, sounds, videos and the web server itself Apache. The number of solutions for this server is therefore growing continuously, these services are becoming more and more complex and expensive, without being able to fulfill the needs of the users. The absence of benchmarks for websites with dynamic content is the major obstacle to research in this area. These users place high demands on the speed of access to information on the Internet. This is why the performance of the web server is critically important. Several factors influence performance, such as server execution speed, network saturation on the internet or intranet, increased response time, and throughputs. By measuring these factors, we propose a performance evaluation strategy for servers that allows us to determine the actual performance of different servers in terms of user satisfaction. Furthermore, we identified performance characteristics such as throughput, resource utilization, and response time of a system through measurement and modeling by simulation. Finally, we present a simple queue model of an Apache web server, which reasonably represents the behavior of a saturated web server using the Simulink model in Matlab (Matrix Laboratory) and also incorporates sporadic incoming traffic. We obtain server performance metrics such as average response time and throughput through simulations. Compared to other models, our model is conceptually straightforward. The model has been validated through measurements and simulations during the tests that we conducted.

Correction and Analysis of Kornai Weibull Queue Model with the Waiting Buyers

First of all, this paper shows clearly careless mistake of Kornai Weibull queue model with the waiting buyers in J.Kornai , as well as Kornai Weibull queue model without waiters . Secondly, strictly prove that revised model has `normal state', under more natural conditions. We advance theory of Kornai Weibull queue model such that deeply understand an abuse of the planned economy.

The queueing model for quantum key distribution network

This paper develops a QKD （quantum key distribution）-based queueing model to investigate the data delay on QKD link and network, especially that based on trusted relays. It shows the mean packet delay performance of the QKD system. Furthermore, it proposes a key buffering policy which could effectively improve the delay performance in practice. The results will be helpful for quality of service in practical QKD systems.

FUNCTIONAL ANALYSIS METHOD FOR THE M/G/1 QUEUEING MODEL WITH OPTIONAL SECOND SERVICE

By studying the spectral properties of the underlying operator corresponding to the M/G/1 queueing model with optional second service we obtain that the time-dependent solution of the model strongly converges to its steady-state solution. We also show that the time-dependent queueing size at the departure point converges to the corresponding steady-state queueing size at the departure point.

Time-dependent analysis for a queue modeled by an infinite system of partial differential equations

By studying the spectrum of the underlying operator corresponding to the exhaustive-service M/G/1 queueing model with single vacations we prove that the time-dependent solution of the model strongly converges to its steady-state solution.

Development and Investigation of the Program Model of Multichannel Queueing System with Unreliable Recoverable Servers in Matlab Environment

In real life, in different industries, we often deal with systems designed for multiple use for performing single-type tasks. Processes taking place at this time are called service of requirements, and the systems themselves—Queueing Systems. This article is dedicated to computer software modelling of processes taking place in the systems in question, Markov processes in particular. In this article, by means of Matlab environment, software realization of one of the typical models of queueing service theory-multichannel QS with unreliable recoverable servers and limited number of requirements in the system, is fulfilled. The results of this research are important because it gives the possibility to use received results to determine optimality degree of some real queueing systems that possess Markov property.

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.

On Optimal Ordering of Service Parameters of a Coxian Queueing Model with Three Phases

We analyze a Coxian stochastic queueing model with three phases. The Kolmogorov equations of this model are constructed, and limit probabilities and the stationary probabilities of customer numbers in the system are found. The performance measures of this model are obtained and in addition the optimal order of service parameters is given with a theorem by obtaining the loss probabilities of customers in the system. That is, putting the greatest service parameter at first phase and the second greatest service parameter at second phase and the smallest service parameter at third phase makes the loss probability and means waiting time minimum. We also give the loss probability in terms of mean waiting time in the system. is the transition probability from j-th phase?to??phase . In this manner while and this system turns into queueing model and while the system turns into Cox(2) queueing model. In addition, loss probabilities are graphically given in a 3D graph for corresponding system parameters and phase transient probabilities. Finally it is shown with a numeric example that this theorem holds.

On Utilizing Model Transformation for the Performance Analysis of Queueing Networks

In this paper, we present an approach for model transformation from Queueing Network Models (QNMs) into Queueing Petri Nets (QPNs). The performance of QPNs can be analyzed using a powerful simulation engine, SimQPN, designed to exploit the knowledge and behavior of QPNs to improve the efficiency of simulation. When QNMs are transformed into QPNs, their performance can be analyzed efficiently using SimQPN. To validate our approach, we apply it to analyze the performance of several queueing network models including a model of a database system. The evaluation results show that the performance analysis of the transformed QNMs has high accuracy and low overhead. In this context, model transformation enables the performance analysis of queueing networks using different ways that can be more efficient.

Analytical Modeling of a Multi-queue Nodes Network Router

This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes （mQN） model. In this model, expressions are derived to calculate two performance metrics, namely, the queue node and system utilization factors. In order to demonstrate the flexibility and effectiveness of the mQN model in analyzing the performance of an mQN network router, two scenarios are performed. These scenarios investigated the variation of queue nodes and system utilization factors against queue nodes dropping probability for various system sizes and packets arrival routing probabilities. The performed scenarios demonstrated that the mQN analytical model is more flexible and effective when compared with experimental tests and computer simulations in assessing the performance of an mQN network router.

乐园游客排队最大接受时长影响因素研究——基于上海迪士尼乐园的实证研究

以ACSI模型为核心,结合ABC态度模型和归因理论等建立了概念模型,旨在探究游客排队最大接受时长的影响因素。将迪士尼乐园作为研究对象,对收集到的220份问卷进行统计分析结果发现,顾客期望维度的四个变量对排队最大接受时长均存在正向影响;游客排队时的感知质量中,游客对于园方排队管理的努力程度的感知以及游乐项目对于游客预期的个性化需求的满足程度对排队最大接受时长有正向影响,而排队的感知时长会对其产生负向影响;排队最大接受时长与顾客的抱怨/不满之间存在负向影响。研究结论为乐园优化游客排队体验,提升游客排队最大接受时长提供了一定的指导。

信号交叉口车辆生态驾驶速度优化策略

为提高交叉口车辆通行效率,降低车辆因频繁启停造成的能耗及污染物排放,提出一种考虑排队长度动态变化的信号交叉口车辆生态驾驶速度优化策略。首先,根据排队长度预测目标车辆与排队队列的碰撞时间(TTC)。其次,将目标车辆通行策略分为匀速、加速、减速三种情况建立通行决策模型,结合改进的三角函数速度优化模型计算最优通行速度,确保车辆以平滑的速度顺利通过信号交叉口。最后,在不同排队长度场景下进行仿真实验,对比分析速度优化策略与无速度优化策略的时空轨迹。仿真结果表明,提出的速度优化策略既可以提高绿灯利用率,又可以降低目标车辆的燃油消耗,相较于无速度优化策略驾驶,燃油消耗最多可降低19.5%,对信号交叉口处车辆生态驾驶有积极作用。

脑卒中住院患者性别、年龄及时空分布特征:基于宁夏地区19万例患者数据

背景脑卒中是血液无法流入大脑而导致脑组织受损的一种急性脑血管疾病,其致残率、致死率以及复发率较高,宁夏地区相关研究多为脑卒中临床相关分析,缺乏对近年宁夏地区脑卒中住院情况的变化趋势分析。目的分析宁夏地区脑卒中住院患者疾病流行特征及分布情况,为制定脑卒中综合防治措施提供依据。方法收集宁夏地区共55家中医及西医医院的病案首页数据,筛选出2013—2019年出院且主要诊断为脑卒中[国际疾病分类(ICD)-10编码为I60~I63]的数据进行分析。应用SPSS 24.0软件采用χ^(2)检验对性别及年龄进行差异性分析,应用地理信息系统采用全局空间自相关分析方法对宁夏地区2013—2019年脑卒中住院率数据的分布进行分析。结果最终纳入190634例脑卒中患者数据。2013—2019年宁夏地区脑卒中住院率呈逐年上升趋势(住院率分别为24.302/10000、30.045/10000、34.949/10000、39.397/10000、44.049/10000、47.617/10000、52.944/10000,χ_(趋势)^(2)=5.982,P=0.014),且在每年的寒冷季节住院率较高,每年3月份有1个明显的高峰,之后稍有下降。2013—2019年宁夏地区脑卒中住院患者中,缺血性脑卒中167194例,出血性脑卒中23440例;缺血性脑卒中和出血性脑卒中患者不同性别、年龄比较,差异有统计学意义(χ^(2)=473.533、7518.543,P<0.05);且从数据上看,缺血性脑卒中和出血性脑卒中男性、≥60岁住院患者所占比例均超过50%。全局空间自相关分析结果显示,2013年、2018年和2019年脑卒中住院率存在空间聚集性(P<0.05)。空间分布图显示,宁夏地区住院的脑卒中患者主要集中在宁夏中北部。结论2013—2019年宁夏地区脑卒中患者住院率表现为不断上升且存在不同程度的聚集性,住院率较高的地区集中在宁夏中北部。

基于年龄-时期-队列模型的中国睾丸癌疾病负担研究

目的分析1990-2019年中国睾丸癌的发病和死亡情况,并探讨年龄、时期和队列效应对睾丸癌发病和死亡的影响。方法利用全球疾病负担(Global Burden of Disease,GBD)2019数据库,分析1990-2019年中国睾丸癌发病和死亡情况,应用Joinpoint软件分析标化发病率和标化死亡率的时间变化趋势,计算平均年度变化百分比。构建年龄-时期-队列模型,分析年龄、时期和出生队列效应对睾丸癌发病及死亡趋势变化的影响。结果2019年,中国睾丸癌发病率为1.21/10万,死亡率为0.08/10万,发病率和死亡率比1990年升高了348.15%和14.29%。1990-2019年,中国睾丸癌标化发病率呈升高趋势,平均每年升高5.23%,趋势有统计学意义(P<0.05),睾丸癌标化死亡率呈下降趋势,平均每年下降0.12%,但趋势无统计学意义(P>0.05)。年龄效应结果显示,1990-2019年中国睾丸癌的发病率和死亡率整体呈升高趋势,发病率和死亡率均在60岁以后呈快速升高趋势,在85岁以上年龄组达到高峰。时期效应结果显示,1990-2019年,中国睾丸癌发病风险的时期变化相对危险度(relative ratio,RR)呈升高趋势,在2015-2019年发病风险最高,发病风险RR=2.44[95%可信区间(confidence interval,CI)2.31~2.56];睾丸癌死亡风险的时期变化RR值趋势呈下降趋势,1995-1999年死亡风险最高,死亡风险RR=1.09(95%CI 0.99~1.19)。队列效应结果显示,出生越晚的人,发病风险越高,死亡风险越低。结论1990-2019年,中国居民睾丸癌的标化发病率呈升高趋势,标化死亡率呈下降趋势但无统计学意义。不同年龄、时期和出生队列的睾丸癌流行病学模式和趋势可能为公共卫生提供新的见解,这些发现可为进一步减轻睾丸癌负担的公共卫生策略的制定提供重要依据。

区块链增强的低空智联网可信协作架构及集群构建策略

低空生态的繁荣不断推动智能网络服务由平面向低空三维立体方向转变,低空业务呈现出规模化、协同化和智能化等演进态势,对低空智联网跨域设备协作能力、任务处理效率、数据安全性及操作可信性等提出了较严苛要求。集群式多设备联合计算协作可提升低空智联网中复杂化大规模任务的处理效率,然而现有模式仍存在跨域设备协作困难、安全可信性缺乏保障以及资源调度灵活性不足等问题。区块链具有数据及操作不可篡改、公开透明和集体维护等特性,尤为适合在多方参与的低空智联环境中建立高效协作信任。本文提出区块链增强的低空智联网可信协作架构,为低空多源异构智联设备提供链上跨域协作计算与状态同步渠道,并设计深度融合集群任务处理流程的多级共识协议,保障低空智联网协作集群式计算服务的安全性与可信性。针对低空智联网中协作集群链上同步状态的时效性开展分析,并据此提出一种基于排队模型的低空智联协作节点链上状态修正算法与高效集群构建策略,保障链上协作任务处理效率。仿真结果表明所提架构及方案可有效提升低空智联网中协作任务处理效率和资源利用率等性能。

基于状态转移队列模型的战时伤员伤情演变规律研究

目的探讨状态转移队列模型在战时伤员伤情演变研究中的应用,以预测不同阶段伤员状态及数量,评估不同救治方案的救治效果。方法以常见海战伤为例,采用专家访谈法获取伤员伤后不同时间节点、不同救治方案下转归概率数据,建立包括死亡、待后送和归队3种状态下的状态转移队列模型,预测不同救治方案下的伤员伤情演变及转归。结果在假定有100名伤员被击中并处于受伤待后送的初始状态下,比较分析舰艇编队救护所医疗队的7种救治方案,结果显示方案4(伤员在受伤后10 min内接受初级急救、1 h内接受高级急救、3 h内接受早期救治)死亡人数最少(21.4人),归队人数最多(53.8人),救治效果最为显著。结论状态转移队列模型在战时伤员伤情演变规律研究中具有潜在的应用价值,可为制定卫勤保障方案、调控保障行动提供有效的决策支持,但仍需进一步完善。

服务失效状态为吸收状态及重试率为常数的M^([X])/M/1排队模型的主算子的谱分析

研究服务失效状态为吸收状态及重试率为常数的M^([X])/M/1排队模型的主算子在左半复平面中的谱.当顾客的到达率λ,服务员的服务率ν,顾客的重试率α和服务员的服务完成率b满足一定的条件时,证明了实部为-(λ+ν+b)的所有复数都不是该模型主算子的特征值;当λ,ν, α, b满足一定的条件时,证明了区间(-(λ+ν+b),0)中无穷多个点是该主算子的几何重数为1的特征值.

面向异构ICN节点的副本选择算法研究

信息中心网络(ICN)是一种革新式网络架构,打破了传统TCP/IP网络端到端传输的限制,提升内容分发效率。ICN构建全网规模的缓存系统,在网络内采用多副本冗余的方式缓存数据内容,以便用户就近获取。与传统互联网缓存系统不同,ICN的缓存呈现泛在化的特点,工作设备是网络基础设施,导致服务资源的异构性普遍存在。在这种环境下,选择适当的副本节点成为重要研究问题。本文首先通过M/M/1排队模型对异构ICN节点进行抽象建模和分析,然后将异构副本节点的选择建模成多臂老虎机问题,继而引入UCB1算法来探索并学习最优决策。仿真实验结果表明,该算法在提高缓存服务可靠性和缩短内容获取时延方面具有明显优势,算法使服务可靠性达到99.15%,将内容获取的平均时延最大缩短8.63%。

人口老龄化、工业机器人与产业雁阵效应

随着国际分工重构和“人口红利”的消失,利用工业智能化促进产业结构转型升级成为亟须解决的重要问题。本文基于IFR机器人数据与WIOD投入产出表,考察人口老龄化背景下工业机器人如何影响产业雁阵效应。研究发现:人口老龄化显著加剧了产业转移,工业机器人则能够显著延缓产业转移;国家经济越强劲、人口红利越消退,工业机器人延缓产业转移效果越显著,并且高度自动化在后人口红利时期能够显著延缓产业转移。工业机器人通过劳动结构和劳动收入影响产业转移,人口老龄化则对“雁头”和“雁尾”产业影响差异较大。因此,要合理把握工业机器人的推广和应用,加大人力资本投入以深化人口红利,分类推进产业分工转移和转型升级。

面向数据中心的控制器排队性能评估模型研究

软件定义网络SDN(Software-Defined Networking)是通过逻辑控制器对整个网络进行集中控制管理,这种集中式的软件管理保证了网络的开放性且有利于管理,但极易造成网络性能瓶颈。为此,在SDN实际部署网络场景之前,对SDN控制器所在的网络进行性能评估是当前所面临的问题。设计了一种基于排队论在SDN控制器所控制的网络数据中心的性能评估模型,根据SDN在数据中心的Fat-Tree部署模式,及多个OpenFlow交换机发送的Packet-in消息过程特点,分析了Packet-in消息在控制器中的处理时间分布情况。以此为基础,构建了该排队解析模型的理论推导过程和主要性能指标参数,并评估了SDN控制器的处理性能。最后,通过该模型测试了控制器性能,并与现有测试模型进行比较。实验结果表明:该模型比现有测试模型更接近于工具Cbench所测性能指标参数,对实际部署控制器应用网络数据中心具有一定的性能参考价值。