Optimizing Real-Time Performance of 3D Virtual Mining Environment with MultiGen Creator

System optimization plays a crucial role in developing VR system after 3D modeling, affecting the system's Immersion and Interaction performance enormously. In this article, several key techniques of optimizing a virtual mining system were discussed: optimizing 3D models to keep the polygon number in VR system within target hardware's processing ability; optimizing texture database to save texture memory with perfect visual effect; optimizing database hierarchy structure to accelerate model retrieval; and optimizing LOD hierarchy structure to speed up rendering.

Real-time performance of periodic data transmission in EPA industrial Ethernet

To evaluate and improve the real-time performance of Ethernet for plant automation（EPA） industrial Ethernet,the real-time performance of EPA periodic data transmission was theoretically and experimentally studied.By analyzing information transmission regularity and EPA deterministic scheduling mechanism,periodic messages were categorized as different modes according to their entering-queue time.The scheduling characteristics and delivery time of each mode and their interacting relations were studied,during which the models of real-time performance of periodic information transmission in EPA system were established.On this basis,an experimental platform is developed to test the delivery time of periodic messages transmission in EPA system.According to the analysis and the experiment,the main factors that limit the real-time performance of EPA periodic data transmission and the improvement methods were proposed.

Real-time crash prediction on freeways using data mining and emerging techniques

Recent advances in intelligent transportation system allow traffic safety studies to extend from historic data-based analyses to real-time applications. The study presents a new method to predict crash likelihood with traffic data collected by discrete loop detectors as well as the web-crawl weather data. Matched case-control method and support vector machines （SVMs） technique were employed to identify the risk status. The adaptive synthetic over-sampling technique was applied to solve the imbalanced dataset issues. Random forest technique was applied to select the contributing factors and avoid the over-fitting issues. The results indicate that the SVMs classifier could successfully classify 76.32% of the crashes on the test dataset and 87.52% of the crashes on the overall dataset, which were relatively satisfactory compared with the results of the previous studies. Compared with the SVMs classifier without the data, the SVMs classifier with the web-crawl weather data increased the crash prediction accuracy by 1.32% and decreased the false alarm rate by 1.72%, showing the potential value of the massive web weather data. Mean impact value method was employed to evaluate the variable effects, and the results are identical with the results of most of previous studies. The emerging technique based on the discrete traffic data and web weather data proves to be more applicable on real- time safety management on freeways.

Real-time hybrid simulation of structures equipped with viscoelastic-plastic dampers using a user-programmable computational platform

A user-programmable computational/control platform was developed at the University of Toronto that offers real-time hybrid simulation （RTHS） capabilities. The platform was verified previously using several linear physical substructures. The study presented in this paper is focused on further validating the RTHS platform using a nonlinear viscoelastic-plastic damper that has displacement, frequency and temperature-dependent properties. The validation study includes damper component characterization tests, as well as RTHS of a series of single-degree-of-freedom （SDOF） systems equipped with viscoelastic-plastic dampers that represent different structural designs. From the component characterization tests, it was found that for a wide range of excitation frequencies and friction slip loads, the tracking errors are comparable to the errors in RTHS of linear spring systems. The hybrid SDOF results are compared to an independently validated thermal- mechanical viscoelastic model to further validate the ability for the platform to test nonlinear systems. After the validation, as an application study, nonlinear SDOF hybrid tests were used to develop performance spectra to predict the response of structures equipped with damping systems that are more challenging to model analytically. The use of the experimental performance spectra is illustrated by comparing the predicted response to the hybrid test response of 2DOF systems equipped with viscoelastic-plastic dampers.

REAL-TIME SOFTWARE SYSTEM FOR PRODUCTION PROCESS SUPERVISION

The real-time software system for production process supervision is a inte-gral system,including on-line function subsystem for supervision and off-line auxiliarysubsystem for development and diagnosis.This paper introduces a real-time software sys-tem which has been used in a power station for monitoring a large capacity thermal gener-ating unit.The subsystems,environment,performance and development of the system areexplained,and the common problems about real-time software system are described.

Multiserver Multichannel Real-Time System with Limited Maintenance Facilities under Maximum Load

We consider a multi server and multichannel real-time system with identical servers (e.g. unmanned aerial vehicles, machine controllers, etc.) that provide services for requests of real-time jobs arriving via several different channels (e.g. surveillance regions, assembly lines, etc.) working under maximum load regime. Each channel has its own constant numbers of jobs inside at any instant. Each channel has its own specifications, and therefore different kinds of equipment and inventory are needed to serve different channels. There is a limited number of identical maintenance teams (less than the total number of servers in the system). We compute analytically steady- state probabilities of this system, its availability, loss penalty function and other performance characteristics, when both service and maintenance times are exponentially distributed.

Real Time Systems with Nonpreemptive Priorities and Ample Maintenance Facilities

We consider a real time data acquisition and processing multiserver system with identical servers (such as unmanned aerial vehicles, machine controllers, overhearing devices, medical monitoring devices, etc.) which can be maintained/programmed for different kinds of activities (e.g. passive or active). This system provides a service for real time tasks arriving via several channels (such as surveillance regions, assembly lines, communication channels, etc.) and involves maintenance. We focus on the worst case analysis of the system with ample maintenance facilities exponentially distributed time to failure and maintenance times. We consider two kinds of models (with and without nonpreemptive priorities) and provide balance equations for steady state probabilities and various performance measures, when both operation and maintenance times are exponentially distributed.

Design of Intelligent Network Performance Analysis & Forecast Support System

A system designed for supporting the network performance analysis and forecast effort is presented, based on the combination of offline network analysis and online real-time performance forecast. The off-line analysis will perform analysis of specific network node performance, correlation analysis of relative network nodes performance and evolutionary mathematical modeling of long-term network performance measurements. The online real-time network performance forecast will be based on one so-called hybrid prediction modeling approach for short-term network, performance prediction and trend analysis. Based on the module design, the system proposed has good intelligence, scalability and self-adaptability, which will offer highly effective network performance analysis and forecast tools for network managers, and is one ideal support platform for network performance analysis and forecast effort.

Performance Evaluation of Multiple Unmanned Aerial Vehicles Operating in General Regime with Shortage of Maintenance Facilities

We consider a real-world problem of military intelligence unit equipped with multiple identical unmanned aerial vehicles (UAV) responsible for several regions (with requests of real-time jobs arriving from independent sources). We suppose that there are no ample maintenance facilities, allowing simultaneous treatment of all vehicles if necessary. Under certain assumptions, these real-time systems can be treated using a queueing theory methodology and/or as Markov chains. We show how to compute steady-state probabilities of these systems, their performance effectiveness, and various performance parameters (for exponentially distributed service and maintenance times of UAVs, as well as tasks duration and their arrival pattern).

基于改进VINS-Mono算法的状态估计方法

针对传统的即时定位并建图(simultaneous localization and mapping,SLAM)算法在位姿识别过程中对精度的要求,在VINS-Mono(visual inertial system-Mono)的前端部分,增加了逆向光流法;针对SLAM算法对实时性的要求,在VINS-Mono的后端滑窗优化方法中,融合了一种边缘化优化算法,再对除相机位姿的部分进行边缘化,然后边缘化相机的位姿部分,从而加速边缘化的过程.再使用EuRoc(European robotics challenge)数据集进行实验,结果发现针对前端的改进策略,精度提升不明显,并分析了原因;针对后端的改进策略,改进算法的边缘化时间平均减少了25.9%,又对比了改进算法与源码的轨迹精度,发现误差可控.最后验证了对VINS-Mono后端的改进策略在实时性上具有优越性.

CTCS-3级列控系统临时限速建模与验证

为了满足临时限速系统的实时性要求,采用时间自动机理论,对CTCS-3级列控系统临时限速工作流程分别建立了各设备的时间自动机子模型,进而构成临时限速系统的时间自动机网络模型,并基于临时限速系统技术规范的参数对模型进行赋值;采用BNF语法对临时限速系统待验证的属性进行了形式化描述,并应用UPPAAL验证工具对临时限速模型的安全性和受限活性进行仿真验证.验证结果表明:与现有临时限速系统的时间参数设置相比,修正后的时间参数设置避免了出现系统死锁现象;在不影响安全功能属性和受限活性的基础上,提高了临时限速系统的实时性,可在规范规定时间5 s内做出响应.

HBV-DNA定量检测试剂盒性能验证

目的验证和评价一种新采购的HBV-DNA定量检测试剂盒的分析性能。方法依据美国临床和实验室标准化协会颁布的EP系列文件和《医学实验室质量和能力认可准则》相关文件对试剂盒的精密度、正确度、线性范围、检测下限和不同检测试剂的一致性进行性能评价。结果试剂盒的低值和中值的批内精密度CV为3.2%、3.4%,总精密度CV为4.6%、3.7%;正确度符合要求;线性回归方程为Y=0.958 X＋0.355,r2=0.999,P〈0.001,线性范围为（1.48×103～1.48×108）U/mL;检测下限为500 U/mL;与原有检测试剂之间结果无差异。结论新试剂盒的性能符合厂家声明,能够应用于临床工作。

超声波破碎-高效液相色谱法定量检测核酸

采用超声波破碎结合高效液相色谱技术,建立了定量检测质粒DNA的方法,测量结果可以溯源至核苷酸标准物质。采用超声波破碎(功率300 W,频率24 kHz)技术将质粒DNA破碎成200～500 bp的小片段DNA,再用蛇毒磷酸二酯酶将其水解为4种核苷酸(dCMP:3.2 min;dTMP:4.7 min;dGMP:5.3 min,dAMP:6.8 min),将产物通过HPLC分离后,采用外标法进行定量分析。应用此方法对待测质粒pNK603进行定量分析,测定的4种核苷酸的摩尔百分比(A∶T=0.95,C∶G=0.98)与理论值接近。本方法的测定结果(47.24μg/g)与实时荧光定量聚合酶链式反应(PCR,45.98μg/g)和PicoGreen荧光染料法(46.02μg/g)的测定结果没有显著差异,表明建立的超声波-HPLC方法可以应用于质粒DNA的定量分析。

PROFIBUS-DP主站网关设计及其关键技术

针对标准PROFIBUS-DP从站产品难以集成到现有集散式控制系统的问题,提出了网关解决方案.在对现有网关实现方案进行比较后,选用软核方案,设计了具有热插拔功能且兼容两种实现方案的硬件平台.采用模块化设计思想进行软件架构,应用状态机法实现了"PROFIBUS-DP通信"子功能.从防错设计、纠错设计、故障恢复设计等方面对设计方案中软、硬件可靠性进行了详细分析.针对硬件特性,从调度策略的角度阐述了影响系统实时性的关键问题,并对自主设计主站的难点问题-组态设计进行了说明.该方案支持系统运行过程中动态地增加和删除从站,修改从站配置参数.分析并实验测试了网关的性能参数,网关最高支持3 Mbit/s的通信波特率.实验结果表明,系统性能优越,运行稳定.

HBV-DNA检测试剂的性能评估与室内质控数据评价

参照美国临床实验室标准化委员会(CLSI)文件,对临床检验使用的实时荧光定量PCR扩增检测试剂盒定量结果的精密度、正确度、定量限、线性范围及抗污染性进行评价。同时用乙型肝炎病毒核酸(HBV-DNA)试剂盒检测2016年3月~8月两个批号的质控血清HBV-DNA,并计算质控结果、标准曲线斜率、截距和相关系数的均值()、标准差(SD)和变异系数(CV)。其中批内、批间精密度CV分别为1.08%~4.41%、2.17%~2.74%,达到核酸检测试剂盒的国家标准及《医学实验室质量和能力认可准则》中基因扩增检验项目分析性能标准(CV≤5%)。参加2016年卫生部室间质评结果总体平均偏倚为2.03%,准确度符合卫生部质评要求。相关系数r=0.999 9,>0.98,线性关系符合要求。定量限结果符合±0.5个对数数量级的要求(评价中至少22次为阳性)。本室2016年3月~8月测定的室内质控物结果对数的累积均值(±2s)为4.34(4.20~4.44),符合参考范围要求。经验证,实时荧光定量PCR HBV-DNA检测试剂盒的各项性能指标以及室内质控结果满足《医学实验室质量和能力认可准则》要求,可以为临床提供快速、准确的报告。

μC/OS-Ⅲ的实时性测试

为测试嵌入式实时操作系统μC/OS-Ⅲ的实时性,设计了基于ARM Cortex-M3内核的实验平台。该平台由波形发生模块、ARM Cortex-M3硬件模块、单片实时信号采集模块和实时操作系统采集模块4个部分构成。基于STC89C52构建波形发生模块,基于STM32设计ARM Cortex-M3硬件模块,并在STM32上开发实时信号采集模块和实时操作系统采集模块。实验表明,实时操作系统采集模块采集一次比实时信号采集模块消耗更长的时间,且消耗的时间与任务个数成线性关系。

Profibus-DP单主站系统实时性研究

分析了Profibus-DP协议数据链路层的运行机理,详细描述了构成Profibus-DP总线周期的时间参数,给出了报文循环时间、令牌目标轮转时间和系统反应时间这三个Profibus-DP系统实时性能指标的具体计算公式,并结合Profibus-DP单主站系统实例,通过测算系统反应时间分析了影响Profibus-DP单主站系统实时性的因素,最后提出可通过提高通信速率、减少从站数量、减少交换数据量来提高Profibus-DP单主站系统实时性。

基于μC/OS-Ⅱ的Modbus/TCP协议的实现与性能分析

Modbus/TCP是运行在TCP/IP协议之上的应用层实时报文传输协议;分析了Modbus/TCP协议构成,并在实时内核μC/OS-Ⅱ及嵌入式ARM软硬件环境下,将Modbus帧嵌入到TCP帧中,实现了Modbus/TCP协议;通过Modbus/TCP通信组件模型,实现了μC/OS-Ⅱ内核下的C/S通信;提出了嵌入式ARM平台上Modbus/TCP原型测试与性能分析方案;经测试,数据延迟在300帧/秒的发送速率下基本稳定在1.3ms以内,有用数据的传送量约为30kb/s;测试结果表明,Modbus/TCP协议具有较好的实时性与稳定性,能达到工业化标准。

基于RFieldbus的Token-Passing协议实时性能建模

RFieldbus 无线现场总线的 MAC 协议 Token Passing 可看成是一个多台多队列排队系统。在分析了 TTR(令牌目的循环时间)对 RFieldbus 中 3 个优先级队列的服务时间的动态限制后,多台单队列排队模型 RF-P 被提出。对从站的轮巡交换数据任务被转化为RF-P 中的令牌内走步时间,原有的高、低级别两个队列则化成了两个具有不同 Poisson 到达率的 M/G/1/∞服务台。利用排队论中的准守恒 PCL 定律,在将服务时间限制转换为数量限制后,求出了等待响应时间的数学解析式。与试验结果的比较表明,在负载不大于 60%时其偏差度约在 10-20%间。

人5-羟色胺2c受体基因实时荧光定量PCR方法的建立

目的建立5-羟色胺2c受体（5-HTR2c）基因mRNA表达水平的TaqMan real—time PcR检测方法。方法以β-actin为内参基因，根据GenBank中人5-HTR2c及β-actin基因序列，分别设计了2套特异性引物和TaqMan探针，接着对反应的退火温度、引物浓度、探针浓度、Mg^2＋浓度进行优化，然后以优化的条件建立相对定量标准曲线，并对该方法的稳定性进行了分析。结果5-HTR2c及β-actin基因的real—time PCR扩增效率分别为99.9％和100.0％；相对定量标准曲线的CT值线性范围分别为12．2～35．1和11．5～31．5，相关系数分别为0．999及1．000；批内及批问变异系数（8．0％。结论本研究所建立的针对5-HTR2c mRNA表达水平的Taqman real-time PCR检测方法具有扩增效率高、稳定性好等特点，为进一步探索5-HTR2c的功能及其mRNA表达水平的变化和各种疾病发生、发展的相关性提供了有用的方法学基础。