Real-time Performance Evaluation of Line Topology Switched Ethernet

Recently,switched Ethernet has become an active area of research because of its wide uses in industry.However,its uses have various real-time constraints on data communications.This paper analyzes the performance of the line topology switched Ethernet as a data acquisition network.Network calculus theory,which has been successfully applied to assess the real-time performance of packet-switched networks,is used to analyze the networks.To properly describe the activity of switches,a novel approach of modeling data flows into or out of switches is addressed.Based on our model,a concisely analytical expression of the maximal end-to-end delay in line topology switched Ethernet is derived.Finally,the relative simulation results are demonstrated.These results agree well with the analytical results,and thus they validate the data flow modeling techniques.

100G Ethernet Technology and Applications

The increasing requirements for bandwidth drive the 100G Ethernet into use as quickly as possible. The major technologies supporting 100G Ethernet interface include the physical layer channel convergence technology, multi-fiber channel and Wavelength Division Multiplexing (WDM) technology. The key technology for high-speed optical devices at the interface requires a breakthrough. The demands driven by the increase of interface rate require better packet processing and storage, system switching, and backplane technology. In addition, in the network, the transport problem of the new interface should be solved, including defining transport standards and pushing the development of key transport technologies. As far as the cost and requirements are concerned, the commercial application of 100G Ethernet is viable in Metropolitan Area Networks (MANs).

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.

Technology Development and Deployment Strategy of Carrier Ethernet

Carrier Ethernet(CE) is gradually stepping away from standardization and testing to deployment and application in live networks.Although great improvement has been made in the reliability of various CE technologies,there is need for improvement in their Quality of Service(QoS),Operation,Administration and Maintenance(OAM),especially the multi-vendor interoperability.The deployment of CE should be service-oriented,and the factors,such as maturity of related technologies and standards,deployment costs,and the complexity of network reconstruction as well as the interoperability with other vendors,should be taken into full consideration to flexibly select appropriate networking technology for different application scenarios according to technical features.

T-MPLS Technology and Application on Carrier Ethernet

As a connection-oriented packet transport technology,Transport Multi-Protocol Label Switching(T-MPLS) is an important bearer technology for Carrier Ethernet(CE).This article starts with the technological characteristics of T-MPLS,then goes on to the latest T-MPLS standardization progress and challenges,followed by the description of T-MPLS based CE architecture.Next,the article covers several key technologies related with T-MPLS,including the data forwarding plane,control plane,network survivability,and Operation,Administration and Maintenance(OAM).Finally,the article analyzes the applications of T-MPLS based CE.

Established and Emerging Optical Technologies for the Real-Time Detection of Cervical Neoplasia: A Review

Cervical cancer remains a critically important problem for women, especially those women in the developing world where the case-fatality rate is high. There are an estimated 528,000 cases and 266,000 deaths worldwide. Established screening and detection programs in the developed world have lowered the mortality from 40/100,000 to 2/100,000 over the last 60 years. The standard of care has been and continues to be: a screening Papanicolaou smear with or without Human Papilloma Virus (HPV) testing;followed by colposcopy and biopsies and if the smear is abnormal;and followed by treatment if the biopsies show high grade disease (cervical intraepithelial neoplasia (CIN) grades 2 and 3 and Carcinoma-in-situ). Low grade lesions (Pap smears with Atypical Cells of Uncertain Significance (ASCUS), Low Grade Squamous Intraepithelial Lesions (LGSIL), biopsies showing HPV changes or showing CIN 1);are usually followed for two years and then treated if persistent. Treatment can be performed with loop excision, LASER, or cryotherapy. Loop excision yields a specimen which can be reviewed to establish the diagnosis more accurately. LASER vaporizes the lesion and cryotherapy leads to tissue destruction. Under long term study;loop excision, LASER, and cryotherapy have the same rate of cure. The standard of care is expensive and takes 6 - 12 weeks for the individual patient. During the last twenty years, new technologies that can view the cervix and even image the cervix with cellular resolution have been developed. These technologies could lead to a new paradigm in which diagnosis and treatment occurs at a single visit. These technologies include fluorescence and reflectance spectroscopy (probe or wide-field, whole cervix scanning approaches) and fluorescence confocal endomicroscopy or high resolution micro-endoscopy. Both technologies have received Federal Drug Administration (FDA) and have been commercialized. Research trials continue to show their remarkable performance. These technologies are reviewed and clinical trials are summarized. Emerging technologies are coming along that may compete with those already approved and include optical coherence tomography, optical coherence tomography with autofluorescence, diffuse optical microscopy, and dual mode micro-endoscopy. These technologies are also reviewed and where available, clinical data is reported. Optical technologies are ready to diffuse into clinical practice because they will save money and 3 or 4 visits in the developed world and offer the same standard of care to the developing world where more cervical cancer exists.

Ring Network Technology for Carrier Ethernet

The fast development of IP services forces the traffic flow in the networks to move gradually from Time Division Multiplexing(TDM) services to packet data services.To adapt to the change,low-cost Ethernet technologies are introduced into the Metropolitan Area Network(MAN).Ring network control protocols and ring network protection technologies are applied to guarantee manageability and reliability required in the telecom networks.The Ethernet Ring Protection(ERP) and Resilient Packet Ring(RPR) are two different ring protection technologies.The Transport Multi-Protocol Label Switching(T-MPLS) network uses the T-MPLS Shared Protection Ring(TM-SPRing) technology to provide ring protection.Carriers can expand the protection as needed and use appropriate ring technologies to meet the requirements of Carrier Ethernet(CE).

基于Ethernet-APL的新型工业控制系统设计

两线制以太网Ethernet-APL通信技术,以其供电、高带宽、远距离、防爆设计成为目前工业领域最具潜力的现场通信技术,国内产业链正在积极推动Ethernet-APL芯片、仪表、交换机、控制系统的研发。从工业控制系统角度,提出了Ethernet-APL新型工业控制系统可能的应用场景以及与之匹配的系统架构。同时,也对该控制系统的网络负荷、实时性、网络冗余、仪表IP分配等关键技术提出了设计方案。随着该技术的推广,将会助力仪表智能化及工厂智能制造的实现。

Ethernet-APL简介及在SIS系统的应用展望

简述了以太网高级物理层(Ethernet-APL)技术的发展历程。针对化工装置对全厂控制系统高可靠性和复杂性的要求,从新的以太物理层开放标准用于过程自动化和现场仪表的角度出发,阐述了APL技术的特点及在流程工业的应用优势。介绍并分析了以太网高级物理层在SIS安全仪表系统的应用前景和系统架构的特征,以期为推动APL技术的应用提供参考。

Applying real-time control to enhance the performance of nitrogen removal in CAST system

A bench-scale reactor（72 L） red with domestic sewage, was operated more than 3 months with three operation modes： traditional mode, modified mode and real-time control mode, so as to evaluate effects of the operation mode on the system performance and to develop a feasible control strategy. Results obtained from fixed-time control study indicate that the variations of the pH and oxidation-reduction potential（ORP） profiles can represent dynamic characteristics of system and the cycle sequences can be controlled and optimized by the control points on the pH and ORP profiles. A control strategy was, therefore, developed and applied to real-time control mode. Compared with traditional mode, the total nitrogen（TN） removal can be increased by approximately 16% in modified mode and a mean TN removal of 92% was achieved in real-time control mode. Moreover, approximately 12.5% aeration energy was saved in real- time control mode. The result of this study shows that the performance of nitrogen removal was enhanced in modified operation mode. Moreover, the real-time control made it possible to optimize process operation and save aeration energy.

Diagnosis of Mycobacterium tuberculosis using molecular biology technology

Objective:To present an integrated molecular biology dedicated system for tuberculosis diagnosis.Methods:One hundred and five sputum specimens from patients strongly suspected by clinical parameters of tuberculosis were studied by Ziehl-Neelsen staining,by cultivation on solid medium and by a balanced hemincsted fluorometric PCR system(Orange C3TB) that could preserve worker safety and produce a rather pure material free of potential inhibitors. DNA amplification was performed in a low cost tuberculosis termocycler-fluorotneter.Produced double stranded DNA was flurometrically detected.The whole reaction was conducted in one single tube which would not be opened after adding the processed sample in order to minimize the risk of cross contamination with amplicons.Results:The assay was able to delect 30 bacillus per sample mL with 99.8%interassay variation coefficient.PCR was positive in 23(21.9%) tested samples(21 of them were smear negative).In our study it showed a preliminary sensitivity of 94.5%for sputum and an overall specificity of 98.7%.Conclusions:Total run time of the test is 4 h with 2.5 real working time.All PCR positive samples are also positive by microbiological culture and clinical criteria.Results show that it could be a very useful tool to increase detection efficiency of tuberculosis disease in low bacilus load samples.Furthermore,its low cost and friendly using make it feasible to run in poor regions.

Carrier Ethernet Services and Technologies

Carrier Ethernet(CE) services generally refer to the standardized carrier-class transfer services that feature in excellent scalability,reliability,manageability and Quality of Service(QoS) guarantee,and are offered by carriers to users based on Ethernet technologies.One of the important characteristics of CE service is the diversity of its implementation technologies.Enhanced Ethernet technologies consider scalability as their chief objective so as to extend conventional Ethernet bridge technologies;the latest Provider Backbone Bridge Traffic Engineering(PBB-TE) emerges as the technical trend of CE technology.Multi-Protocol Label Switch(MPLS) offers reliable Pseudowire(PW) connections for CE based on Label Switching Path(LSP).The convergence of MPLS and PBB is one of the important evolution trends for CE.Making full use of the existing Optical Transport Network(OTN) infrastructure,the optical ring network technology is the most cost-efficient and effective way to deliver CE services;its future development trend is characterized by enhancing the Operation,Administration and Maintenance(OAM) function and the control plane.

Ethernet-APL技术详解及应用展望

大多数工厂使用4~20 mA模拟信号作为传感器、执行器和过程控制系统之间的通信方式,重要的过程仪表都支持4~20 mA+HART的信号传输技术,但该技术在需要获取更多的过程值变量、诊断信息,或者用于配置设备等时暴露出很大的局限性。介绍一种全新的数据传输技术Ethernet-APL,该技术采用两线制、通信距离长、满足防爆需求、仪表信号和供电共线,实现从现场到应用层的无缝数据交换,满足现代工业数字化的应用需求。

Simple, Flexible, and Interoperable SCADA System Based on Agent Technology

SCADA (Supervisory Control and Data Acquisition) is concerned with gathering process information from industrial control processes found in utilities such as power grids, water networks, transportation, manufacturing, etc., to provide the human operators with the required real-time access to industrial processes to be monitored and controlled either locally (on-site)or remotely (i.e., through Internet). Conventional solutions such as custom SCADA packages, custom communication protocols, and centralized architectures are no longer appropriate for engineering this type of systems because of their highly distribution and their uncertain continuously changing working environments. Multi-agent systems (MAS) appeared as a new architectural style for engineering complex and highly dynamic applications such as SCADA systems. In this paper, we propose an approach for simply developing flexible and interoperable SCADA systems based on the integration of MAS and OPC process protocol. The proposed SCADA system has the following advantages: 1) simple (easier to be implemented);2) flexible (able to adapt to its environment dynamic changes);and 3) interoperable (relative to the underlying control systems, which belongs to diverse of vendors). The applicability of the proposed approach is demonstrated by a real case study example carried out in a paper mill.

Ethernet-APL工程规范中的实践规划示例

Ethernet-APL技术正式公布以来,在中国市场已有多个实施案例,标志该项技术已经走到试用推广的阶段。介绍了电源等级规定,以及6种APL主干线带电源的实践规划示例,同时分析了6种示例的局限性;介绍了将APL现场交换机通过光纤直接连接至工业以太网控制网络的标准交换机的方案。通过对两类APL拓扑结构的总结,为APL的应用推广提供借鉴。

基于Ethernet的网络化测试技术研究

本文对基于 Ethernet的网络化测试技术作了较深入的研究。分析了网络化测试的基本结构和要求 ,从 Ethernet的确定性和性能特点方面论证了 Ethernet可以满足网络化实时测试的要求 ,介绍了网络化测试系统的基本功能单元、采用的 OPC技术及系统的特点。给出了一个具体的实现例子。

交换技术及其在工业以太网EtherNet/IP中的应用

指出了以太网本身机制在实时性控制中的缺陷,分析了工业以太网和EtherNet/IP工业控制对实时性和确定性的要求,介绍了交换机的一般交换原理和直通式、存储转发、碎片隔离3种不同的交换方式,并对比了它们的优缺点。针对EtherNet/IP网络的组网和控制要求,具体讨论了交换机的多种控制协议和控制策略及如何应用交换机特性克服以太网本身存在非实时性及大量广播报文引起网络堵塞等缺点。

新一代单对线以太网NG-SPE技术及在流程工业数据通信中的应用

回顾了流程工业两线制通信技术的发展历程,包括4~20mA,HART,RS-485和新兴的APL/10BASE-T1L单对线以太网通信技术,以及各自的优缺点、面临的问题和后续的演进方向;重点介绍了新一代单对线以太网NG-SPE技术,以及该技术在带宽、距离、节点数和供电四个方面的均衡表现。通过与其他主流单对线技术对比后表明,新一代单对线以太网NG-SPE技术可实现在1km内,通信速率为100Mibit/s的数据传输,15节点接入,点到多点供电,并支持多种线缆和拓扑结构,可应用于流程工业、物联等领域,取代低速总线,利用已有线缆,实现高速远距离总线通信。