基于Packet Tracer的无线网络实验研究

随着无线网络速率的不断提高,无线网络得到了空前的发展,许多学校已将无线网络技术加入到教学内容中。提出了一种基于Packet Tracer技术构建虚拟的无线网络实验环境,很好的解决了当前无线网络实践教学存在的问题。实践表明,利用该技术能有效促进学生对无线网络技术的学习兴趣,提高了对该技术的实践教学效率。     

基于Packet Tracer的IPSec VPN虚拟仿真实验设计

本文以PacketTracer仿真软件为平台,结合网络工程项目背景,设计了IPsecVPN技术在校园网中应用的仿真实验。通过给出的具体实验方法及过程,使学生掌握IPsec VPN的配置方法,直观地看到实验效果,激发学生自主学习探究的兴趣。     

基于Packet Tracer 虚拟仿真软件的计算机网络实验教学模式的探索

由于真实网络设备存在造价高、技术更新速度快、维护复杂、实验场所固定等问题,所以将虚拟仿真软件引入到计算机网络实验教学中势在必行。本文介绍了虚拟仿真软件之一Packet Tracer的主要功能及特点,并以RIPV2实验为例,说明了实验过程及使用Packet Tracer时的注意事项,并且本文提出了虚实结合的计算机网络实验教学体系。通过虚实结合的实验教学,为培养具有创新意识和创新能力的高素质应用型人才奠定了坚实的基础。     

Packet Tracer在中职《计算机网络》教学中的应用研究

本文介绍了网络模拟软件Packet Tracer,论述了其在《计算机网络》实训课程教学中应用的优点,阐述了笔者在实际教学中使用Packet Tracer构建虚拟实训平台,借助使用Packet Tracer进行实训技能考核评估,并以此提高了实训课堂教学效果。     

利用Paceket Tracer软件实现跨VLAN数据间通信

本文简要地介绍了虚拟局域网(VLAN)的概念和技术以及思科网院提供的Paceket Tracer模拟软件,较为详细地介绍了如何利用Paceket Tracer实现交换机跨VLAN实现数据通信的配置方法与步骤,给三层交换机接口配置IP地址,采用SVI(交换虚拟接口)的方式实现VLAN间互连。     

基于web的教学管理系统的设计与实现

根据课程改革及教学需要,也为了给师生提供方便的在线作业管理环节,以及为师生提供方便的信息共享和交流平台,文章详细阐述了一个采用当前流行的B/S结构包括在线作业管理、资源管理、新闻管理、论坛管理等于一体的的基于WEB的教学管理系统的设计与实现。     

基于RTree的路网模型设计及实现

通过对交通要素的分析,提出了基于RTree空间索引的路网模型,用于进行公交、自驾、轨道交通等不同场景的最优路线选择,提高了路网分析、索引效率。     

基于云计算的网络教学平台的设计与实现

在以浏览器和服务器为基础的前提之下,相关应用的程序和数据库存储功能都能在云计算模型服务器终端实现。本文在对云计算理论的研究过程中设计出了一个高校的教学平台,且云计算拥有并发计算和定制服务双重优点,对信息资源的整合优化起着重要的作用,而且基于网络学习策略基础之上将定制服务这一优点展现了出来。     

基于人脸识别技术的机场门禁系统设计及实现

近些年来,随着我国经济的不断发展,科学技术日益进步,机场的客流量也越来越大,人们对航空服务的质量和效率提出了更高的要求。因此,机场门禁系统的缺陷越来越明显,已经无法满足人们对机场门禁系统高安全、高可信的要求。本文分析了当前机场门禁系统的现状,尤其是在身份辨认上,主要依赖人工,然后基于人脸识别技术,对机场门禁系统的设计与实现进行探讨。     

基于BIM的家装设计软件的算法设计及功能实现

家装设计行业是我国建筑领域的重要组成部分。本文的研究工作是基于家装设计行业, 建立了一套基于BIM的家装设计软件系统。文章对软件系统的主要功能实现进行了介绍, 之后针对几项主要功能实现的算法设计思路进行了详尽的分析。文章还给出了软件的操作界面截图, 对软件的功能实现效果进行了说明。该软件的创新性应用能够为家装设计师和客户双方带来家装设计的新体验, 并将推动整个家装产业新模式的发展。     

Comparison of Capture Efficiencies Measured by Tracer Gas and Aerosol Tracer Techniques

Abstract The capture efficiency of an exhaust device was evaluated using a tracer gas (helium diluted in air), and an aerosol tracer of varying particle size distributions. Helium concentrations were measured by mass spectrometry, and those of the aerosol were evaluated using optical and photometric particle counters in order to follow the temporal evolution of the concentrations. This experimental study confirms the theoretical results obtained from mathematical simulations (CFD), and from the simple study of the particle relaxation time and sedimentation velocity of particles. It demonstrates that the transfer of an aerosol to a square local exhaust system of 20×20 cm² is nearly identical to that of a gas when all the following conditions are fulfilled:

• ? diameter of particles less than about 30 μm;
• ? low initial particle emission velocity (of a few tens of cm/s);
• ? direct capture and short transfer times between the source and the capture system (less than a few seconds).

It is then possible to use the tracer gas technique to measure the capture efficiency of an aerosol if the above-mentioned conditions are fulfilled.     

基于思科模拟器中防火墙技术的应用与研究

思科模拟器是学习计算机网络必不可少的软件平台,而防火墙技术是计算机网络中安全防范技术中的重要环节,通过对防火墙的研究,能够更好地学习计算机网络安全技术。文章通过思科模拟器进行防火墙的配置,并进行了相关的模拟与仿真。     

基于PIC单片机的粉料物料运输车自动卸料系统设计

首先,设计控制电路并利用光电耦合元件PC827,将PIC16F877A单片机引脚信号与电磁驱动器电路进行隔离,减少外界干扰单片机输出信号,防止电磁执行器的误操作。其次,利用PIC16F877A单片机A/D转换模块,将工作时粉料物料运输车罐体内气压表的模拟电压转换成数字信号,通过LED实时显示当前的气压值。最后,在MPLAB上利用HI-TECH PICC编译器编写控制程序,并通过Proteus在线仿真进行验证。     

体检人群血尿酸水平与代谢综合征及其组分的关系研究

目的:探讨体检人群血尿酸(SUA)水平与代谢综合征(MS)及其组分的关系。方法:选取2017年4月-2018年4月本院体检者600例,均检测MS相关指标水平(HDL-C、LDL-C、Scr、TC、TG、SUA、DBP、SBP、FPG、BMI、GFR)及各组分(高血糖、高血压、超重或肥胖、血脂紊乱)。观察HUA检出率并定义其为HUA组,其余均为正常尿酸(NUA)组;比较两组MS相关指标水平及各组分检出率;分析MS相关指标与SUA水平之间的关系。结果:本研究HUA检出率为16.17%(97/600),其中男、女分别为19.00%、13.33%;HUA组LDL-C、Scr、TC、TG、SUA、DBP、SBP、FPG、BMI水平、MS及各组分检出率均高于NUA组,年龄、HDL-C、GFR均低于NUA组,差异均有统计学意义(P<0.05);经Spearman相关分析得知,SUA与TG、TC、BMI、Scr、FPG、SBP、DBP、LDL-C水平均呈正相关(P<0.05),而与GFR、HDL-C均呈负相关(P<0.05);经多因素Logistic回归分析,血脂紊乱、肥胖或超重、男性、年龄均能增加HUA风险(P<0.05)。结论:SUA水平升高与MS相关指标及各组分密切相关,可将其作为风险预测及MS筛查的有效指标。     

A Simple Method Using Tracer Gas to Identify the Main Airflow and Contaminant Paths within a Room

The main airflow and contaminant paths or the spatial distribution of the age of air (or contaminant) in a room are of great interest in estimating venrilation efficiency. A simple meusurement method is presented which consists of injecting one or more tracer gases at locations of interest and analysing the concentration at several other locations, carefully chosen for best accuracy. Response functions can be fitted to these measurements, which are the age of the tracers or of the air or the concentration of the tracers as a function of the location. The salient paths, such as the dead zones, are also determined from these functions. The paper presents the method, its application and validation in a well controlled test room.     

基于Android平台的管线调绘系统设计与实现

城市地下管线是城市公共基础设施的关键,如何快速、高效地维护更新地下管线信息成为城市管理中需要面临的重要问题。本文介绍了在管线数据采集过程中,采用基于Android平台设计并开发的移动GIS数据采集系统,不同于传统的纸质作业流程,移动GIS数据采集系统能够减少内业工序,降低传统内业手工录入数据属性过程中出现错误的概率,提高了工作效率。     

基于Android的变电站地理位置导航系统的设计与实现

文章针对供电公司电力检修业务的实际需求,文章设计并实现了一种基于安卓(Android)平台的变电站地理位置实时导航系统。介绍了系统总体架构和客户端APP结构,重点论述了变电站数据加密和解密、离线数据包传输、地址查询和定位导航等功能模块的设计和实现。系统采用了开源的安卓(Android)系统、密钥包含手机设备标识符的对称加密算法和百度地图API,数据安全,运行稳定可靠,定位和导航精确度高,同时具有成本低和升级维护方便等特点,极大地提高了电网巡检维修人员的工作效率。     

The predictions of infection risk of indoor airborne transmission of diseases in high-rise hospitals: Tracer gas simulation

The spread of diseases from infected patients within hospitals is resulting in many human casualties. If a virus were to be transmitted through uncontrolled air movement within a hospital and were then to infect other patients or healthy visitors, it would be impossible to contain the spread of the disease. The purpose of this paper is to apply reliable boundary conditions based on previous studies in order to analyze the airflow pattern caused by the stack effect in high-rise hospitals. An analysis was carried out on the vertical airborne transmission of viruses according to the location of the infected patients. The horizontal airborne transmission based on the characteristics of the supply air diffuser and return air grille was also analyzed by using the multi-zone airflow simulation and tracer gas (CFD) simulation. In addition, this paper explored solutions to prevent the spread of airborne pathogenic bacteria by analyzing various alternatives of HVAC systems and basic data on ventilation system planning for high-rise hospitals.     

The airborne transmission of infection between flats in high-rise residential buildings: Tracer gas simulation

Airborne transmission of infectious respiratory diseases in indoor environments has drawn our attention for decades, and this issue is revitalized with the outbreak of severe acute respiratory syndrome (SARS). One of the concerns is that there may be multiple transmission routes across households in high-rise residential buildings, one of which is the natural ventilative airflow through open windows between flats, caused by buoyancy effects. Our early on-site measurement using tracer gases confirmed qualitatively and quantitatively that the re-entry of the exhaust-polluted air from the window of the lower floor into the adjacent upper floor is a fact. This study presents the modeling of this cascade effect using computational fluid dynamics (CFD) technique. It is found that the presence of the pollutants generated in the lower floor is generally lower in the immediate upper floor by two orders of magnitude, but the risk of infection calculated by the Wells–Riley equation is only around one order of magnitude lower. It is found that, with single-side open-window conditions, wind blowing perpendicularly to the building may either reinforce or suppress the upward transport, depending on the wind speed. High-speed winds can restrain the convective transfer of heat and mass between flats, functioning like an air curtain. Despite the complexities of the air flow involved, it is clear that this transmission route should be taken into account in infection control.