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.

Packet Scheduling Algorithm for Real-Time Services in Broadband WMAN

Packet scheduling algorithm is the key technology to guarantee Quality of Service (QoS) and balance the fairness between users in broadband Wireless Metropolitan Area Network (WMAN). Based on the research of Proportional Fairness (PF) algorithm and Modified Largest Weighted Delay First (M-LWDF) algorithm, a new packet scheduling algorithm for real-time services in broadband WMAN, called Enhanced M-LWDF (EM-LWDF), was proposed. The algorithm phases in new information to measure the load of service queues and updates the state parameters in real-time way, which remarkably improves system performance.Simulation results show that comparing with M-LWDF algorithm, the proposed algorithm is advantageous in performances of queuing delay and fairness while guaranteeing system throughput.

Models to Simulate Effective Coverage of Fire Station Based on Real-Time Travel Times

In recent years,frequent fire disasters have led to enormous damage in China.Effective firefighting rescues can minimize the losses caused by fires.During the rescue processes,the travel time of fire trucks can be severely affected by traffic conditions,changing the effective coverage of fire stations.However,it is still challenging to determine the effective coverage of fire stations considering dynamic traffic conditions.This paper addresses this issue by combining the traveling time calculationmodelwith the effective coverage simulationmodel.In addition,it proposes a new index of total effective coverage area(TECA)based on the time-weighted average of the effective coverage area(ECA)to evaluate the urban fire services.It also selects China as the case study to validate the feasibility of the models,a fire station(FS-JX)in Changsha.FS-JX station and its surrounding 9,117 fire risk points are selected as the fire service supply and demand points,respectively.A total of 196 simulation scenarios throughout a consecutiveweek are analyzed.Eventually,1,933,815 sets of valid sample data are obtained.The results showed that the TECA of FS-JX is 3.27 km^(2),which is far below the standard requirement of 7.00 km^(2) due to the traffic conditions.The visualization results showed that three rivers around FS-JX interrupt the continuity of its effective coverage.The proposed method can provide data support to optimize the locations of fire stations by accurately and dynamically determining the effective coverage of fire stations.

Real-time RT-PCR Assay for the detection of Tahyna Virus

A real-time RT-PCR （RT-qPCR） assay for the detection of Tahyna virus was developed to monitor Tahyna virus infection in field-collected vector mosquito samples. The targets selected for the assay were S segment sequences encoding the nucleocapsid protein from the Tahyna virus. Primers and probes were selected in conserved regions by aligning genetic sequences from various Tahyna virus strains available from GenBank. The sensitivity of the RT-qPCR approach was compared to that of a standard plaque assay in BHK cells. RT-qPCR assay can detect 4.8 PFU of titrated Tahyna virus. Assay specificities were determined by testing a battery of arboviruses, including representative strains of Tahyna virus and other arthropod-borne viruses from China. Seven strains of Tahyna virus were confirmed as positive; the other seven species of arboviruses could not be detected by RT-qPCR. Additionally, the assay was used to detect Tahyna viral RNA in pooled mosquito samples. The RT-qPCR assay detected Tahyna virus in a sensitive, specific, and rapid manner; these findings support the use of the assay in viral surveillance.

Real-time RT-PCR Assay for the Detection of Culex flavivirus

Based on the Culex flavivirus (CxFV) E gene sequences in GenBank, CxFV-specific primers and probes were designed for real-time reverse transcription-polymerase chain reaction (RT-qPCR). The specificity test revealed that CxFV could be detected using RT-qPCR with the specific CxFV primers and probes; other species of arboviruses were not detected. The stability test demonstrated a coefficient of variation of <1.5%. A quantitative standard curve for CxFV RT-qPCR was established. Quantitative standard curve analysis revealed that the lower detection limit of the RT-qPCR system is 100 copies/mu L. Moreover, RT-qPCR was used to detect CxFV viral RNA in mosquito pool samples. In conclusion, we established a real-time RT-PCR assay for CxFV detection, and this assay is more sensitive and efficient than general RT-PCR. This technology may be used to monitor changes in the environmental virus levels.

Bolzano Traffic: An Example of Open ITS Deployment for Advanced Traveller Information Services

This paper aims to present the experience gathered in the Italian alpine city of Bolzano within the project“Bolzano Traffic”whose goal is the introduction of an experimental open ITS platform for local service providers,fostering the diffusion of advanced traveller information services and the future deployment of cooperative mobility systems in the region.Several end-users applications targeted to the needs of different user groups have been developed in collaboration with local companies and research centers;a partnership with the EU Co-Cities project has been activated as well.The implemented services rely on real-time travel and traffic information collected by urban traffic monitoring systems or published by local stakeholders(e.g.public transportation operators).An active involvement of end-users,who have recently started testing these demo applications for free,is actually on-going.

Transmission Considerations with QoS Support to Deliver Real-Time Distributed Speech Recognition Applications

Distributed speech recognition (DSR) applications have certain QoS (Quality of service) requirements in terms of latency, packet loss rate, etc. To deliver quality guaranteed DSR application over wirelined or wireless links, some QoS mechanisms should be provided. We put forward a RTP/RSVP transmission scheme with DSR-specific payload and QoS parameters by modifying the present WAP protocol stack. The simulation result shows that this scheme will provide adequate network bandwidth to keep the real-time transport of DSR data over either wirelined or wireless channels.

An integrated DBP for streams with （m, k）-firm real-time guarantee

(m, k)-firm real-time or weakly hard real-time (WHRT) guarantee is becoming attractive as it closes the gap between hard and soft (or probabilistic) real-time guarantee, and enables finer granularity of real-time QoS through adjusting m and k. For multiple streams with (m, k)-firm constraint sharing a single server, an on-line priority assignment policy based on the most recent k-length history of each stream called distance based priority (DBP) has been proposed to assign priority.In case of priority equality among these head-of-queue instances, Earliest Deadline First (EDF) is used. Under the context of WHRT schedule theory, DBP is the most popular, gets much attention and has many applications due to its straightforward priority assignment policy and easy implementation. However, DBP combined with EDF cannot always provide good performance, mainly because the initial DBP does not underline the rich information on deadline met/missed distribution,specially streams in various failure states which will travel different distances to restore success states. Considering how to effectively restore the success state of each individual stream from a failure state, an integrated DBP utilizing deadline met/missed distribution is proposed in this paper. Simulation results validated the performance improvement of this pro-posal.

AN INTELLIGENT METHOD FOR REAL-TIME DETECTION OF DDOS ATTACK BASED ON FUZZY LOGIC

The paper puts forward a variance-time plots method based on slide-window mechanism tocalculate the Hurst parameter to detect Distribute Denial of Service(DDoS)attack in real time.Basedon fuzzy logic technology that can adjust itself dynamically under the fuzzy rules,an intelligent DDoSjudgment mechanism is designed.This new method calculates the Hurst parameter quickly and detectsDDoS attack in real time.Through comparing the detecting technologies based on statistics andfeature-packet respectively under different experiments,it is found that the new method can identifythe change of the Hurst parameter resulting from DDoS attack traffic with different intensities,andintelligently judge DDoS attack self-adaptively in real time.

Performance analysis of real-time and post-mission kinematic precise point positioning in marine environments

This article focuses on the performance analysis of both real-time and post-mission kinematic precise point positioning(PPP)in challenging marine environments.For this purpose,a real dynamic experiment lasting 6 h was carried out on a lake dam in?orum City of Turkey.While the kinematic test was continuing,the real-time PPP coordinates were obtained for each measurement epoch with a commercial real-time PPP(RT-PPP)service,namely the Trimble Center Point RTX.Then the post-mission PPP(PM-PPP)coordinates were calculated by using Multi-GNSS data and the Multi-GNSS Experiment(MGEX)precise products.The kinematic RT-PPP and PM-PPP results showed that the PPP coordinates were consistent with the relative solution at centimetre and decimetre level in horizontal and height components,respectively.This study implies that PPP technique is a powerful tool for highly accurate positioning in both real-time and post-mission modes,even for dynamic applications in harsh environments.

Efficient Harmonic Analysis Technique for Prediction of IGS Real-Time Satellite Clock Corrections

Real-time satellite orbit and clock corrections obtained from the broadcast ephemerides can be improved using IGS real-time service (RTS) products. Recent research showed that applying such corrections for broadcast ephemerides can significantly improve the RMS of the estimated coordinates. However, unintentional streaming interruption may happen for many reasons such as software or hardware failure. Streaming interruption, if happened, will cause sudden degradation of the obtained solution if only the broadcast ephemerides are used. A better solution can be obtained in real-time if the predicted part of the ultra-rapid products is used. In this paper, Harmonic analysis technique is used to predict the IGS RTS corrections using historical broadcasted data. It is shown that using the predicted clock corrections improves the RMS of the estimated coordinates by about 72%, 58%, and 72% in latitude, longitude, and height directions, respectively and reduces the 2D and 3D errors by about 80% compared with the predicted part of the IGS ultra-rapid clock corrections.

802.11协议中RTS/CTS机制的安全漏洞分析

802.11协议中的RTS/CTS机制可以解决隐藏节点问题,通过分析RTS/CTS机制中的安全漏洞,发现由于RTS/CTS握手过程中没有认证机制,攻击者可以通过连续发送设定足够大网络分配矢量值的伪造RTS/CTS帧,以达到拒绝服务攻击的目的。在理论分析的基础上,使用aircrack-ng的软件开发包,在真实的无线网络环境中进行了实验,实验结果显示,RTS/CTS机制确实存在着被拒绝服务攻击的安全漏洞,可随时被攻击者利用,需引起充分重视。

A Cooperative QoS Management Scheme Based on DiffServ Network for Real-Time Service

In this paper,an improved scheme based on DiffServ network is proposed to provide a decentralized coopera-tive QoS management for real-time services'admission control and resources'monitoring.The proposed scheme consists of aQoS Control Server(QoSCS),a Service Management Server(SMS),a Network Management Server(NMS)and routersin the concerned management domain.When an application asks for a service with specific QoS requirements,a series ofcooperation are initiated among these components by means of a suit of signaling protocol.Once a service is admitted,itcan provide required QoS services more effectively than original DiffServ network.Monitoring per-flow states are movedfrom edge routers to the QoSCS server.The prototype implementation and experimental results show that this scheme canprovide enhanced manageability and scalability for providing per-flow management in such a distributed way.

Priority-Based Resource Allocation for Downlink OFDMA Systems Supporting RT and NRT Traffics

Efficient radio resource management is essential in Quality-of-Service (QoS) provisioning for wireless communication networks. In this paper, we propose a novel priority-based packet scheduling algorithm for downlink OFDMA systems. The proposed algorithm is designed to support heterogeneous applications consisting of both real-time (RT) and non-real-time (NRT) traffics with the objective to increase the spectrum efficiency while satisfying diverse QoS requirements. It tightly couples the subchannel allocation and packet scheduling together through an integrated cross-layer approach in which each packet is assigned a priority value based on both the instantaneous channel conditions as well as the QoS constraints. An efficient suboptimal heuristic algorithm is proposed to reduce the computational complexity with marginal performance degradation compared to the optimal solution. Simulation results show that the proposed algorithm can significantly improve the system performance in terms of high spectral efficiency and low outage probability compared to conventional packet scheduling algorithms, thus is very suitable for the downlink of current OFDMA systems.

封头RT检测过程自动化探究

封头的检测是火工品检测要求中极为严格的一个环节,达到国家一级缺陷检测要求。本文通过对封头检测采用RT方法的观察和研究,设计可自动放底片、取片、换片的自动化检测工艺方案。并对设计结构做可靠性试验。该自动化检测方案大大减少对人工的依赖,提高检测效率,也解放生产力,而且延长核心设备服役期限,极大程度改善落后的生产条件。也为该行业其他设备由纯人工操作向自动化检测改造升级提供依据。

Toward the Fourth Industrial Revolution on Real-Time Customization

The outputs of a national economy can be partitioned into three sets of products:tangible goods(due to manufacturing,construction,extraction and agriculture),intangible services(due to an act of useful effort),and an integration of services and goods or,as initially defined by Tien(2012),servgoods.Actually,these products can also be considered in terms of their relation to the first three Industrial Revolutions:the First Industrial Revolution(circa 1800)was primarily focused on the production of goods;the Second Industrial Revolution(circa 1900)was primarily focused on the mass production of goods;and the Third Industrial Revolution(circa 2000)has been primarily focused on the mass customization of goods,services or servgoods.In this follow-up paper,the Third Industrial Revolution of mass customization continues to accelerate in its evolution and,in many respects,is subsuming the earlier Industrial Revolutions of production and mass production.More importantly,with the advent of real-time decision making,artificial intelligence,Internet of Things,mobile networks,and other advanced digital technologies,customization has been extensively enabled,thereby advancing mass customization into a Fourth Industrial Revolution of real-time customization.Moreover,the moral,ethical,security and employment problems associated with both mass and real-time customization must be carefully assessed and mitigated,especially in regard to unintended consequences.Looking ahead and with the advance of artificial general intelligence,this Fourth Industrial Revolution could be forthcoming in about the middle of the 21st Century;it would allow for multiple activities to be simultaneously tackled in real-time and in a customized manner.

Enhancing the OGC WPS interface with GeoPipes support for real-time geoprocessing

Real-time geospatial information is used in various applications such as risk management or alerting services.Especially,the rise of new sensing technologies also increases the demand for processing the data in real time.Today’s spatial data infrastructures,however,do not meet the requirements for real-time geoprocessing.The OpenGIS®Web Processing Service(WPS)is not designed to process real-time workflows.It has some major drawbacks in asynchronous processing and cannot handle(geo)data streams out of the box.In previous papers,we introduced the GeoPipes approach to share spatiotemporal data in real time.We implemented the concept extending the Message Queue and Telemetry Transport(MQTT)protocol by a spatial and temporal dimension,which we call GeoMQTT.In this paper,we demonstrate the integration of the GeoPipes idea in the WPS interface to expose standardized real-time geoprocessing services.The proof of the concept is illustrated in some exemplary real-time geo processes.

Web服务行为兼容性的判定与计算

确保Web服务行为兼容是实现Web服务无缝集成与协作的一个重要问题.在服务视图概念的基础上,给出了Web服务行为兼容性的相关定义.提出一种基于π演算的Web服务行为兼容性的定性判定与定量计算方法.该方法首先通过算法自动地将Web服务行为和Web服务间的交互行为表达成π演算进程,然后借助π演算的操作语义和形式化推演实现服务行为兼容性自动的定性判定;随后在π演算的进程变换理论的基础上提出算法实现服务兼容性自动的定量计算.该方法在服务动态组合与服务动态替换中的典型应用表明,该方法对于服务组合的正确建立和可靠执行具有重要作用.

基于中标麒麟的POWERLINK节点实时性解决方法

针对运行于中标麒麟操作系统上的POWERLINK标准节点难以保证实时性的问题,提出了一种通用的解决方案。该方案分别从对中标麒麟进行实时扩展和把POWERLINK协议栈编译成内核模块两个方面着手,降低了POWERLINK应用工程相关任务的服务响应时间,进而提高了POWERLINK节点的实时性能。

日本服务机器人:“产学官”协同创新实践模式研究

服务机器人产业是日本的战略性新兴产业,一直拥有着强劲的国际竞争力。以下一代日本服务机器人核心技术RT中间件(robot technology middleware)为例,通过构建"产学官"协同创新模型,考察日本发展下一代服务机器人在知识创造、技术创新及培养人才方面的创新实践。研究表明,日本下一代服务机器人的发展,在产品设计上选择模块化产品架构,新能源产业技术综合开发机构(NEDO)为RT中间件的研发打造开放性创新平台,整合"产""学""官"的相关知识,通过"产学官"协同创新模式研发出RT中间件,并通过采取RT中间件源代码开放和标准化策略,进而推进服务机器人核心技术在国内外市场应用,同时重视相关人才培育。鉴于中国机器人产业"高端产业低端化"现状,结合日本培育服务机器人产业的经验,对中国机器人产业发展提出重构产业创新平台、加强人才培育等对策建议。