Correlation analysis between fault frequency and service time of underground fluid instruments

In this paper, we make a statistical analysis of the fault information of the underground fluid instruments of 12 models in China from January 2021 to May 2022 based on the Pearson correlation coefficient, and compare the fault statistics of the meteorological three-element instruments of 3 models during the study period. The results show that:(1) The numbers of faults of the underground fluid instruments of 12models with different service times are basically positively correlated with the numbers of the corresponding instruments, with good consistency. Moreover, the automatic observation instruments(8models) with more than 30 units are significantly correlated at a 0.05 significance level(95% confidence level). Even at a 0.01 significance level(99% confidence level), there are 7 models(7/8) with significant correlation.(2) The positive and negative correlations between the monthly average number of faults and the corresponding service times of the underground fluid instruments of 12 models with different service times are random, and there are 9 models(75%) with no significant correlation at a 0.05 significance level(95% confidence level), while 12 models(100%) with no significant correlation at a 0.01significance level(99% confidence level).(3) The monthly average numbers of faults of the underground fluid instruments of 12 models are basically 0.02-0.05 times/(unit·month), and the overall fault frequency is low.(4) The fault statistics results of the meteorological three-element instruments of 3 models are consistent with the characteristics of the underground fluid instruments of 12 models. In general,there is no significant correlation between the fault frequency and the service time of underground fluid instruments.(5) The results of this paper demonstrate that the service time of underground fluid instruments cannot be taken as the main reason for whether to update the instruments. Similarly, the fault frequency of the instruments cannot be taken as the main reason for the service life of the instruments in the process of formulating the service life standards of underground fluid instruments.

Factors Influencing the Emergency Medical Service Response Time for Cardiovascular Disease in Guangzhou, China

While emergency medical service (EMS) response time (ERT) is a major factor associated with the survival of patients with cardiovascular disease (CVD), relatively few studies have explored the factors associated with ERT. This study aimed to assess the current status of ERT and to identify the factors affecting ERT in patients with CVD in China. Between January 1, 2011 and December 31, 2015, EMS responses to CVD incidents in Guangzhou, China, were examined. The primary outcome was ERT, defined as the time from receipt of an emergency call to the arrival of paramedics on the scene. Factors associated with ERT were evaluated by multivariable logistic regression. A total of 44 383 CVD incidents were analysed. The median ERT was 12.58 min (interquartile range=9.98-15.67). Among the risk factors, distance (OR=13.73, 95% CI=11.76- 16.04), level of hospital (OR=1.57, 95% CI=1.40-1.75), and site of the incident (OR=1.53, 95% CI=1.38-1.69) were the top three significant factors affecting the ERT. Our results suggest that greater attention should be given to factors affecting the ERT. It is essential to make continuous efforts to promote the development of effective interventions to reduce the response time.

Two-echelon inventory model with service level constraint and controllable lead time sensitive to order quantity

The decision-making and optimization of two-echelon inventory coordination were analyzed with service level constraint and controllable lead time sensitive to order quantity.First,the basic model of this problem was established and based on relevant analysis,the original model could be transformed by minimax method.Then,the optimal order quantity and production quantity influenced by service level constraint were analyzed and the boundary of optimal order quantity and production quantity was given.According to this boundary,the effective method and tactics were put forward to solve the transformed model.In case analysis,the optimal expected total cost of two-echelon inventory can be obtained and it was analyzed how service level constraint and safety factor influence the optimal expected total cost of two-echelon inventory.The results show that the optimal expected total cost of two-echelon inventory is constrained by the higher constraint between service level constraint and safety factor.

Delivery Service Management System Using Google Maps for SMEs in Emerging Countries

This paper proposes a Delivery Service Management(DSM)system for Small and Medium Enterprises(SMEs)that own a delivery fleet of pickup trucks to manage Business-to-Business(B2B)delivery services.The proposed DSM system integrates four systems:Delivery Location Positioning(DLP),Delivery Route Planning(DRP),Arrival Time Prediction(ATP),and Communication and Data Sharing(CDS)systems.These systems are used to pinpoint the delivery locations of customers,plan the delivery route of each truck,predict arrival time(with an interval)at each delivery location,and communicate and share information among stakeholders,respectively.The DSM system deploys Google applications,a GPS tracking system,Google Map APIs,ATP algorithms(embedded in Excel Macros),Line,and Telegram as supporting tools.To improve the accuracy of the ATP system,three tech-niques are applied considering driver behaviors.The proposed DSM system has been implemented in a Thai SME.From the process perspective,the DSM system is a systematic procedure for end-to-end delivery services.It allows the interactions between planner-driver decisions and supporting tools.The supporting tools are simple,can be easily used with little training,and require low capital expenditure.The statistical analysis shows that the ATP algorithm with the three techniques provides high accuracy.Thus,the proposed DSM system is beneficial for practitioners to manage delivery services,especially for SMEs in emerging countries.

A DISCRETE TIME TWO-LEVEL MIXED SERVICE PARALLEL POLLING MODEL

We present a discrete time single-server two-level mixed service polling systems with two queue types, one center queue and N normal queues. Two-level means the center queue will be successive served after each normal queue. In the first level, server visits between the center queue and the normal queue. In the second level, normal queues are polled by a cyclic order. Mixed service means the service discipline are exhaustive for center queue, and parallel 1-limited for normal queues. We propose an imbedded Markov chain framework to drive the closed-form expressions for the mean cycle time, mean queue length, and mean waiting time. Numerical examples demonstrate that theoretical and simulation results are identical the new system efficiently differentiates priorities.

Improved Radio Network Dimensioning for Real-Time Polling Service on IEEE 802.16 Wireless Networks with QoS Consideration

Recently, applications of real-time polling service (rtPS) in IEEE 802.16 wireless networks have gained considerable popularity. These applications generate large amounts of real time traffic in the network and thus maintaining the quality of service (QoS) such as packet delay requirement in rtPS dominant networks is critical. Existing dimensioning methodology does not consider QoS parameters of rtPS in network dimensioning. Moreover, exhaustive and time-consuming simulations are required to evaluate the performance and QoS of rtPS. To overcome this problem, we propose an improved radio network dimensioning framework which considers QoS parameters of rtPS in network dimensioning. In this framework, an analytical model is developed to evaluate the capacity and performance of rtPS in IEEE 802.16 wireless networks. The proposed framework provides a fast and accurate means of finding the trade-off between system load and packet delay, thus providing network operators with an analytical tool that jointly considers coverage, capacity and QoS requirements for obtaining the minimum number of sites required. The accuracy of the proposed model is validated through simulations.

An Energy-Efficient Mobile-Controlled Vertical Handover Management for Real Time Services

Multiple wireless access technology has been embedded into a single mobile device as a fundamental feature, aiming to give end users ubiquitous access at any time. To allow the users to enjoy the ubiquitous connectivity, the mobile device has to consume higher energy for the simultaneous activation of multiple wireless interface and the continuous connectivity. In addition, a seamless vertical handover between the access technologies is a mandatory requirement to insure the quality, reliability and continuity of real time services. In this paper, the continuity of real time services as well as energy saving for mobile devices has been taken into account. The conceptual idea is that whenever traffic rate is lower than a threshold it will be smoothly handed over to a low energy consumption technology, i.e., Bluetooth. When the traffic exceeds the limitation of Bluetooth bandwidth, it will be handed over to a wider bandwidth technology, i.e., Wi-Fi. In the considered scenarios, the technologies are not interconnected;hence, the vertical handover management must be fully controlled by the mobile devices. The performance of the system including energy saving and maintaining the continuity of real time services has been evaluated by direct measurements in a real testbed.

Precise Point Positioning Technique with IGS Real-Time Service (RTS) for Maritime Applications

The maritime navigation accuracy requirements for radionavigation systems such as GPS are specified by the International Maritime Organization (IMO). Maritime navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with an accuracy requirement that ranges from 10 m to 0.1 m. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP) and with the advent of the new IGS-Real-Time-Service (RTS), it is necessary to assess the possibility of a wider role of the PPP-based positioning technique in maritime applications. This paper investigates the performance of an autonomous real-time PPP-positioning solution by using the IGS- RTS service for maritime applications that require an accurate positioning system. To examine the performance of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is investigated. It is shown that the real-time IGS-RTS PPP-based GPS positioning technique fulfills IMO requirements for maritime applications with an accuracy requirement ranges from 10 m for Ocean/Coastal/Port approach/Inland waterways navigation to 1.0 m for in port navigation but cannot fulfill the automatic docking application with an accuracy requirement of 0.10 m. To further investigate the real-time PPP-based GPS positioning technique, a comparison is made between the real-time IGS-RTS PPP-based positioning technique and the real-time PPP-based positioning by using the predicted part of the IGS Ultra-Rapid products and the real-time GPS positioning technique with the Wide Area Differential GPS service (WADGPS). It is shown that the IGS-RTS PPP-based positioning technique is superior to the IGS-Ultra-Rapid PPP-based and WADGPS-based positioning techniques.

一种基于Web Service的分级QoS的研究与实现

随着WebService技术的广泛应用,QoS成为一个非常重要的问题.以服务响应时间为QoS参数,验证了一种基于WebService的分级QoS方法,提出了目标时间预设模型,并针对优化问题提出一种基于动态规划的解决方法,并实现了原型系统.实验数据表明这种方法有效地控制了负载平衡,实现了服务分级.

基于时间序列分析的Web Service QoS预测方法

通过网络提供服务的Web Service的服务质量会随着网络环境、服务器负载等因素的变化而变化,如何更好地帮助用户选择在未来一段时间内符合服务质量需求的Web Service,是目前服务计算领域中需要解决的关键问题之一。针对上述问题,提出了一种基于时间序列分析的Web Service QoS预测方法,并实现了相应的Web Service QoS自动预测工具。该工具能够根据Web Service的历史QoS数据,有效地预测未来短期内的QoS信息。以17832个Web Service的历史数据为基础,设计了相关实验,并验证了方法的有效性。

基于Web Services的网络时间同步

将Web Services技术引入时间同步研究领域,不仅建立了面向网络时间同步服务的Web Services体系结构,而且详细讨论了网络时间同步服务的建立、部署过程以及客户端的实现。Web Services的引入对网络时间同步协议的研究具有重要的意义。

Web Service在MES数据传输中的应用

Web Service是由企业发布的完成其特定商务需求的在线应用服务,应用软件能够通过Internet来访问并使用这项在线服务。制造执行管理系统(MES)要求实时反映车间生产状态,对数据传输的完备性与实时性要求较高,本文介绍了Web Services技术和它在数据传输方面的优势,以及如何将Web Service技术应用于MES数据传输中,以达到MES对数据传输的性能要求。

基于Webservice的危险品监管及应急救援协同平台研究

针对我国危险品运输多个部门监管现状,提出了基于Webservice数据交换技术的"危险品监管及应急救援协同平台"建设方案。该方案能解决"危险品运输多部门监管数据不一致以及难以协同应急救援"这一实际问题。设计了协同平台的技术框架,描述了二类不同用途的车载终端"监控终端"和"智能终端"的基本功能,并以环保部门为例阐述了服务平台与危险废物监管政务平台之间的数据交换及功能耦合,以及利用服务平台开展危险品运输事故应急救援联动的流程实例。还阐述案例中的Webservice数据交换方法,以及多源数据动态更新机制,并作了总结。

多元时间序列的Web Service QoS预测方法

为准确并多步预测 Web 服务的服务质量(quality of service,简称 QoS),方便用户选择更好的 Web 服务,提出了一种基于多元时间序列的 QoS 预测方法 MulA-LMRBF(multiple step forecasting with advertisement-levenbergmarquardt radial basis function).充分考虑多个 QoS 属性序列之间的关联,采用平均位移法(average dimension,简称AD)确定相空间重构的嵌入维数和延迟时间,将 QoS 属性历史数据映射到一个动力系统中,近似恢复多个 QoS 属性之间的多维非线性关系.将短期服务提供商 QoS 广告数据加入数据集中,采用列文伯格-马夸尔特法(Levenberg-Marquardt,简称 LM)算法改进的径向基(radial basis function,简称 RBF)神经网络预测模型,动态更新神经网络的权重,提高预测精度,实现 QoS 动态多步预测.通过网络开源数据和自测数据的实验结果表明,该方法与传统方法相比有较好预测效果,更适合动态多步预测.

基于Web Service的煤矿信息系统的设计

Web Service是目前开发分布式系统的主要技术,Web Service具有节省用户开发时间和实现异构平台互通的优点。基于C/S(Client/Server)模式的煤矿信息系统大多是用组态软件开发的,需要在每台客户机上安装相应的客户端程序,不能实现快速部署和配置,维护和管理的难度大,不利于扩展,通常局限于小的局域网,此外基于B/S(Browser/Server)模式的系统多使用ASP和HTML技术开发,安全性较差,对服务器要求过高,难以适应分布式应用的需要。本文提出了一种基于Web Service的煤矿信息系统,并在实际生产中得到了成功的应用。

ANALYSIS ON A TYPE OF SERVICING MACHINES MODEL WITH REPAIRABLE SERVICE STATION

This paper deals with a type of servicing machines model, which service station has a life time of the kth Er-langian distribution and can be repaired just like a new one. The cyclic time and the inefficiency quantities of this system in equilibrium are obtained.

基于Web Service的实时收费系统及其实现

介绍一个为民办高校服务了4年的学生收费系统,与现在流行的B/S与C/S结构的收费系统相比,它是一个基Web Service技术和运用多个不同数据库而实现的收费系统,其效率非常高,适合在民办高校中,现场进行现金交费及票据打印。经多年的实践,能单日完成上千学生的收费。最后,添加了Web Service查找数据库实例,这使读者更具体了解WebService的实现。

基于XML Web Service和Ajax的Web实时分布式系统的架构及应用

如果WEB系统的用户数比较多、数据计算比较复杂、数据库访问量比较大,人机交互量比较大,就会使传统的Web系统无法满足用户的实时性要求。通过XML Web Service可以均衡Web服务器的负载,创建分布式Web系统;通过Ajax可以创建无需等待、无需刷新的Web交互模式。本文提出了基于XML Web Service和Ajax的Web实时分布式系统的架构方案,并进行了具体应用。

一种WebService响应时间的动态预测方法

随着Web Service技术的迅速发展,具有相同或相似功能的服务在互联网上大量出现.如何预测服务质量,进而支持基于服务质量的服务选择,成为了需要解决的关键问题.其中,响应时间是服务消费者最能直接感受到的服务质量体现,提出一种Web服务响应时间的动态预测方法.该方法根据响应时间的历史数据,基于时间序列分析进行动态预测.实验结果表明,这种方法可以显著提高预测的准确性,更好地支持服务的选择.