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.

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.

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.

Serial Communications Programming in Windows95 with API Functions

This paper introduces the usage of these functions. It presents the technique of how to program with them to perform the serial communications between a computer and other digital devices by the serial porst in Windows95. The related sample codes of the applications of this technique written in C++ programming language are also given. This technique is applied successfully to receive the data of the radio noise from a frequency monitor.

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.

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.

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.

Optimization of Serial Port of General Flex Pendant for Industrial Robot

In order to further improve the serial ports communication mode of the general Flex Pendant for industrial robot,a multiple serial communication mode is put forward. It is used to meet the stability of data transmission,transmission distance,transmission speed,anti-interference and cost-effective. Using ADUM1201 single direction dual channel digital isolator,two pieces of MAX13487 E and a piece of MAX3232 chip to transmit data and files, and to control chip’ s electrical level. Selecting the RS232, RS422 and RS485 communication mode,the serial ports of the general Flex Pendant of industrial robot is optimized.

基于Simulink的USB数据传输库的实现

Simulink是一个强大的系统建模、仿真和分析的图形化工具包,提供了大量的模块,方便用户快速的建立动态的模型。而且利用MATLAB的RTW能直接将Simulink所建立的模型生成优化的、可移植的代码,并根据目标配置自动生成多种环境下的不同程序。这个功能可以使得设计人员从编写嵌入式软件代码的繁复工作中解脱出来,将主要精力集中在系统设计上。然而Simulink嵌入式目标模块库中的DSP与PC的通讯接口模块过于简单,速率较低,不能满足大数据量的要求。作者在Simulink上开发了USB数据传输库,能通过RTW生成特定硬件平台的执行代码。实例表明,该模块成功有效,可以极其方便的应用在各种需要与目标实时通讯的场合。

A Novel Design of Efficient Multi-channel UART Controller Based on FPGA

In traditional universal asynchronous receiver transmitter （UART） controller, the data transmission is inefficient and the data bus utilization ratio is low. A novel design is provided to solve these problems. The architecture of the system is introduced, the flow charts of data processing as well as the implementation state machine are also presented in detail. This paper is concluded by comparing the performance of this design, which is realized on field programmable gate army （FPGA） using Verilog hardware description language （HDL）, with other traditional UART controllers.

DESIGN OF A NOVEL DEXTEROUS ROBOT HAND

In the robotic community more and more hands are developed. Based on theexperience of HIT Hand and DLR Hand II, a smaller and easier manufactured dexterous robot hand withmultisen-sory function and high integration is jointly developed. The prototype of the hand issuccessfully built. It has 4 fingers in total 13-DOFs (degree of freedom). Each finger has 3-DOFsand 4 joints, the last 2 joints are mechanically coupled by means of four-bar linkage mechanism. Italso has an additional DOF to realize motion of the thumb relative to the palm. The fingertip forcecan reach up to 10 N. Full integration of mechanical body, actuation system, multisensory system andelectronics is a significant feature. DSP based control system is implemented in PCI busarchitecture and the serial communication between the hand and DSP needs only 2 lines.

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.

Research on network integration technology of observation stations

According to the phenomenon of "four more"and"four low "problems in the observation stations,the surface-based meteorological observing system can't adapt to the change of the adaptive observation equipment and reduce of business intensification. A station integrated system is proposed,w hich can be configured,connected and extended to all kinds of observation equipment. And the integrated processor is designed,supporting a variety of communication interface standards. Flexible configuration,connection and expansion betw een conventional and new type of meteorological observation equipment are supported. It is capable for online calibration and maintenance of observation equipment. The effectiveness of automatic observation equipment is totally achieved to provide basic information support for disaster prevention and mitigation and national economic development.

基于PDA的陀螺全站仪通信与数据处理系统研究与开发

讨论在嵌入式操作系统WindowsCE下以PDA作为一个数据接口实现了陀螺寻北仪和全站仪之间接口通信,并将PDA采集到的陀螺寻北仪定向数据和全站仪测得的测量数据进行实时处理,得到贯通测量定向数据。

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.

Adjusting the Parameters of PI Regulator in All-electrical Tank Gun Control System by Computer Program

Both the traverse subsystem and the elevation subsystem of the all-electrical tank gun control system are composed of electrical drive control system respectively. The parameters of PI regulator in these electrical drive control systems affect the performance of the control system seriously. Up to now, there is not a simple and practical method for choosing regulator parameters, which are usually determined by repeated and continual readjustment. This method is low efficient, and the parameters got are not always optimal. A method for on-line adjusting the parameters of PI regulator in the electrical drive control system by computer program is introduced in this paper. The function of adjusting PI parameters of the electrical drive control system is realized by PC program written by VC++ and controlling program written by assemble language and by the communication between PC and DSP completed by the control MSCOMM in VC++6.0. The method as mentioned above which is applied for an all-electrical tank gun control system under development is proved very available, a better performance might be obtained for the all-electrical tank gun control system easily.