An On-Line Scheduler over Hard Real-Time Communication System

By thorough research on the prominent periodic and aperiodic scheduling algorithms,anon-line hard real-time scheduler is presented,which is applicable to the scheduling of packets over a link.This scheduler,based on both Rate Monotonic,pinwheel scheduling algorithm Sr and Polling Serverscheduling algorithms,can rapidly judge the schedulability and then automatically generate a bus tablefor the scheduling algorithm to schedule the packets as the periodic packets.The implementation of thescheduler is simple and easy to use,and it is effective for the utilization of bus link.The orderly executionof the bus table can not only guarantee the performance of the hard real time but also avoid the blockageand interruption of the message transmission.So the scheduler perfectly meets the demand of hard real-time communication system on the field bus domain.

Real-time Audio &Video Transmission System Based on Visible Light Communication

With the increasing popularity of solid sate lighting devices, Visible Light Communication (VLC) is globally recognized as an advanced and promising technology to realize short-range, high speed as well as large capacity wireless data transmission. In this paper, we propose a prototype of real-time audio and video broadcast system using inexpensive commercially available light emitting diode (LED) lamps. Experimental results show that real-time high quality audio and video with the maximum distance of 3 m can be achieved through proper layout of LED sources and improvement of concentration effects. Lighting model within room environment is designed and simulated which indicates close relationship between layout of light sources and distribution of illuminance.

A Novel Medium Access Control Protocol for Real-Time Wireless Communications in Industrial Automation

In this paper, a novel Medium Access Control (MAC) protocol for industrial Wireless Local Area Networks (WLANs) is proposed and studied. The main challenge in industry automation systems is the ultra-low network latency with a target upper bound in the order of 1 ms while maintaining high network reliability and availability. The novelty of the proposed wireless MAC protocol resides in its similar latency performance as its counterpart in wired industrial LAN. First, the functional design of the MAC protocol is introduced. Then its performance results gained from hardware implementation (SystemC and VHDL) on an FPGA platform are presented. Finally, a real-time communication module which achieves the ultra-low latency required in industrial automation is described.

Design of Real-time Electricity Prices and Wireless Communication Smart Meter

Under the background of smart grid’s real-time electricity prices theory, a real-time electricity prices and wireless communication smart meter was designed. The metering chip collects power consumption information. The real-time clock chip records current time. The communication between smart meter and system master station is achieved by the wireless communication module. The “freescale” micro controller unit displays power consumption information on screen. And the meter feedbacks the power consumption information to the system master station with time-scale and real-time electricity prices. It results that the information exchange between users and suppers can be realized by the smart meter. It fully reflects the demanding for communication of smart grid.

Real-Time Communication Method for mHealth Base on Extended XMPP Protocol

Considering characteristic of mHealth communication and problems of existing methods, this paper presents a real-time communication method for mHealth based on extended XMPP protocol. The method can maintain the role status efficiently and reduce data latency during the communication process. Meanwhile, it can be extended flexibly to meet increasing communication demands of mHealth services. Furthermore, a system framework is presented to support telemonitoring scene. Finally, system implementation and feasibility tests verify the effectiveness of the method and framework.

The Serial Communication Based on Multithreading Technique of Windows

Present a kind of method which is used to communicate between serial serial port and peripheral equipment dynamicly and real-time using multithreading technique based on the basic principle of communication and multitasking mechanism in the circumstance of Windows. This method resolves the question of Real-time answering in the serial communication validly, reduces losing rate of data and improves reliability of system. This article presents a general method used in the serial communication which is practical.

The development of a new real-time subsurface mooring

Subsurface mooring allows researchers to measure the ocean properties such as water temperature,salinity,and velocity at several depths of the water column for a long period.Traditional subsurface mooring can release data only after recovered,which constrains the usage of the subsurface and deep layer data in the ocean and climate predictions.Recently,we developed a new real-time subsurface mooring(RTSM).Velocity profiles over upper 1000 m depth and layered data from sensors up to 5000 m depth can be realtime transmitted to the small surface buoy through underwater acoustic communication and then to the office through Beidou or Iridium satellite.To verify and refine their design and data transmission process,we deployed more than 30 sets of RTSMs in the western Pacific to do a 1-year continuous run during 2016–2018.The continuous running period of RTSM in a 1-year cycle can reach more than 260 days on average,and more than 95%of observed data can be successfully transmitted back to the office.Compared to the widely-used inductive coupling communication,wireless acoustic communication has been shown more applicable to the underwater sensor network with large depth intervals and long transmission distance to the surface.

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.

Simple real-time high-sensitivity heterodyne coherent optical transceiver at intraplane satellite communication

In this paper,we demonstrate a high-sensitivity and real-time heterodyne coherent optical transceiver for intraplane satellite communication,without digital-to-analog converter(DAC)devices and an optical phase lock loop(OPLL).Based on the scheme,a real-time sensitivity of-49 dBm is achieved at 5 Gbps QPSK.Because DAC is not needed at the transmitter,as well as OPLL at the receiver,this reduces the system cost.Furthermore,the least required Rx ADC bit-width is also discussed.Through theoretical analysis and experimental results,our cost-effective transceiver satisfies the scenario and could be a promising component for future application.

Balance energy-efficient and real-time with reliable communication protocol for wireless sensor network

In many wireless sensor network applications, it should be considered that how to trade off the inherent conflict between energy efficient communication and desired quality of service such as real-time and reliability of transportation. In this paper, a novel routing protocols named balance energy-efficient and real-time with reliable communication （BERR） for wireless sensor networks （WSNs） are proposed, which considers the joint performances of real-time, energy efficiency and reliability. In BERR, a node, which is preparing to transmit data packets to sink node, estimates the energy cost, hop count value to sink node and reliability using local information gained from neighbor nodes. BERR considers not only each sender＇ energy level but also that of its neighbor nodes, so that the better energy conditions a node has, the more probability it will be to be chosen as the next relay node. To enhance real-time delivery, it will choose the node with smaller hop count value to sink node as the possible relay candidate. To improve reliability, it adopts retransmission mechanism. Simulation results show that BERR has better performances in term of energy consumption, network lifetime, reliability and small transmitting delay.

A security scheme for intelligent substation communications considering real-time performance

Tampering,forgery and theft of the measurement and control messages in a smart grid could cause one breakdown in the power system.However,no security measures are employed for communications in intelligent substations.Communication services in an intelligent substation have high demands for real-time performance,which must be considered when deploying security measures.This paper studies the security requirements of communication services in intelligent substations,analyzes the security capabilities and shortages of IEC 62351,and proposes a novel security scheme for intelligent substation communications.This security scheme covers internal and telecontrol communications,in which the real-time performance of each security measure is considered.In this scheme,certificateless public key cryptography(CLPKC)is used to avoid the latency of certificate exchange in certificate-based cryptosystem and the problem of key escrow in identity-based cryptosystem;the security measures of generic object-oriented substation event,sampled measure value and manufacturing message specification in IEC 62351 are improved to meet the real-time requirements of the messages as well as to provide new security features to resist repudiation and replay attacks;and the security at transport layer is modified to fit CLPKC,which implements mutual authentication by exchanging signatures.Furthermore,a deployment of CLPKC in an intelligent substation is presented.We also evaluate the security properties of the scheme and analyze the end-to-end delays of secured services by combining theoretical calculation and simulation in this paper.The results indicate that the proposed scheme meets the requirements of security and real-time performance of communications in intelligent substations.

A Low-Cost Efficient Hardware-in-the-Loop Testbed for Distributed Generation Penetration Analysis

In this paper a real-time testbed using hardware-in-the-loop for the analysis of the effects of DGs （distributed generators） on microgrids is presented. The distribution network is implemented in SIMULINK using the IEEE 15-node distribution feeder connected to two DGs feeding the grid using two smart inverters. The inverters＇ active and reactive power control is performed by TI C2000-based controllers and the hardware connections to the system are done through dSPACE interface module. The system is designed such that it can easily be modified to change the location of the DGs and/or to change the number of DGs connected to the grid. Several case study results are presented and compared against simulations to verify the effectiveness and accuracy of the system, model, and the employed power control schemes.

Defining soft skills in nursing:a concept analysis

Objective:To define soft skills in nursing.Methods:This is a concept analysis using the Walker and Avant approach.Multiple electronic databases in the English language including CINAHL,Science Direct,MEDLINE on EBSCOhost,and Scopus were consulted.Results:Soft skills in nursing include the intrapersonal attributes,interpersonal skills,and creativity of the nurse,which,when combined with professionalism,teamwork,and effective communication skills,improve the quality of nursing care and client satisfaction.Conclusions:Although hard and soft skills are compatible and synergetic,soft skills are to be prioritized for the success of nursing care in the healthcare industry.This concept analysis adds to the body of knowledge by identifying the attributes of soft skills in nursing and revealing that a good nurse needs more than just good grades to be successful.

Credit Determination of Fibre Channel in Avionics Environment

Fibre channel （FC） is the main candidate architecture for ＂unified network＂. Flow control deals with the problem in which a device receives frames faster than it can process them. Credit is an important service parameter for fibre channel flow control. Configuring the credit reasonably can avoid buffer overflow in nodes. This paper derives the mathematic relationships among credit, bandwidth and message sets under real-time condition according as three main topologies of fibre channel, and proposes the credit determination and the optimal credit for typical message sets. This study is based on the features of hard real-time communications in avionics environment.

Quality of Service Aware Cluster Routing in Vehicular Ad Hoc Networks

In vehicular ad hoc networks(VANETs),the topology information(TI)is updated frequently due to vehicle mobility.These frequent changes in topology increase the topology maintenance overhead.To reduce the control message overhead,cluster-based routing schemes are proposed.In clusterbased routing schemes,the nodes are divided into different virtual groups,and each group(logical node)is considered a cluster.The topology changes are accommodated within each cluster,and broadcasting TI to the whole VANET is not required.The cluster head(CH)is responsible for managing the communication of a node with other nodes outside the cluster.However,transmitting real-time data via a CH may cause delays in VANETs.Such real-time data require quick service and should be routed through the shortest path when the quality of service(QoS)is required.This paper proposes a hybrid scheme which transmits time-critical data through the QoS shortest path and normal data through CHs.In this way,the real-time data are delivered efciently to the destination on time.Similarly,the routine data are transmitted through CHs to reduce the topology maintenance overhead.The work is validated through a series of simulations,and results show that the proposed scheme outperforms existing algorithms in terms of topology maintenance overhead,QoS and real-time and routine packet transmission.

Conceptual model of real-time IoT systems

We address a special kind of Internet of Things (IoT) systems that are also real-time. We call them real-time IoT (RT-IoT) systems. An RT-IoT system needs to meet timing constraints of system delay, clock synchronization, deadline, and so on. The timing constraints turn to be more stringent as we get closer to the physical things. Based on the reference architecture of IoT (ISO/IEC 30141), the RT-IoT conceptual model is established. The idea of edge subsystem is introduced. The sensing & con-trolling domain is the basis of the edge subsystem, and the edge subsystem usually must meet the hard real-time constraints. The model includes four perspectives, the time view, computation view, communication view, and control view. Each view looks, from a different angle, at how the time parameters impact an RT-IoT system.

Windows and Fieldbus Based Software Computer Numerical Control System

Computer numerical control(CNC)system is the base of modern digital and intelligent manufacturing technolo- gy.And opened its architecture and constituted based on PC and Windows operating system(OS)is the main trend of CNC sys- tem.However,even if the highest system priority is used in user mode,real-time capability of Windows(2000,NT,XP)for applications is not guaranteed.By using a device driver,which is running in kernel mode,the real time performance of Windows can be enhanced greatly.The acknowledgment performance of Windows to peripheral interrupts was evaluated.Harmonized with an intelligent real-time serial communication bus(RTSB),strict real-time performance can be achieved in Windows platform. An opened architecture software CNC system which is hardware independence is proposed based on PC and RTSB.A numerical control real time kernel(NCRTK),which is implemented as a device driver on Windows,is used to perform the NC tasks.Tasks are divided into real-time and non real-time.Real-time task is running in kernel mode and non real-time task is running in user mode.Data are exchanged between kernel and user mode by DMA and Windows Messages.

RTEX A REAL TIME EXECUTIVE FOR DCCS

This paper presents the design idea and implementation of a real time multiprocess executivededicated to a distributed computer control system(abbreviated as DCCS),RTEX.The hostprecessor is an INTEL 8344 microcontroller proper for mini size industrial control work station.A real time executive is designed to provide a friendly environment for users to develop their ownapplied software.In consideration of reliability and ease of maintenance the executive is imple-mented by a hierarchical structure with eight layers which include user applied programs,net-work communication,real time clock manager,interprocess communication,processcoordination,process manager,memory manager,hardware.For practical purpose the networkcommunication software is implemented by four layers,namely physical,datalink,transport andapplication.The bottom two layers are designed according to the Bit Bus protocol,so that thework station is compatible with the INTEL distributed system.Three parts,the kernel,networkcommunication and facilities for system initialization and applied software development are in-cluded.

Design and Implementation of a Real Time Wireless Monitor System for Urinary Incontinence

Urinary incontinence is the most common health problem in aged people. Leaving incontinence events unmanaged will make a negative influence on the aged and the patient both mentally and physically. This paper presents a design and implementation of a real time wireless monitor system for urinary incontinence, which has been applied in two nursing homes in Beijing and Shanghai. We collect real time moisture information by using non-contact humidity sensor designed and manufactured by us. When urinary incontinence, the sensor will send alert to mobile device via Bluetooth. If got the alert, the mobile device will send the alert to relatives of the aged or disabled people and cloud computing platform, through which we can make this information managed and displayed and the paramedic can be informed about the alarm. This paper gives a brief introduction to the framework of this system, the design of the non-contact sensor, the transmission of wireless data and the results of tests.

Convergence to real-time decision making

Real-time decision making reflects the convergence of several digital technologies,including those concerned with the promulgation of artificial intelligence and other advanced technologies that underpin real-time actions.More specifically,real-time decision making can be depicted in terms of three converging dimensions:Internet of Things,decision making,and real-time.The Internet of Things include tangible goods,intangible services,ServGoods,and connected ServGoods.Decision making includes model-based analytics(since before 1990),information-based Big Data(since 1990),and training-based artificial intelligence(since 2000),and it is bolstered by the evolving real-time technologies of sensing(i.e.,capturing streaming data),processing(i.e.,applying real-time analytics),reacting(i.e.,making decisions in real-time),and learning(i.e.,employing deep neural networks).Real-time includes mobile networks,autonomous vehicles,and artificial general intelligence.Central to decision making,especially real-time decision making,is the ServGood concept,which the author introduced in an earlier paper(2012).It is a physical product or good encased by a services layer that renders the good more adaptable and smarter for a specific purpose or use.Addition of another communication sensors layer could further enhance its smartness and adaptiveness.Such connected ServGoods constitute a solid foundation for the advanced products of tomorrow which can further display their growing intelligence through real-time decisions.