The Experts below are selected from a list of 1809 Experts worldwide ranked by ideXlab platform

Chengrui Zhang - One of the best experts on this subject based on the ideXlab platform.

  • ICSAI - A Gigabit Real-time Ethernet for Manufacture Automation Control
    2019 6th International Conference on Systems and Informatics (ICSAI), 2019
    Co-Authors: Chengrui Zhang
    Abstract:

    In order to meet the requirements of communication bandwidth in the field of high-speed and high-precision motion control, a real-time Ethernet communication solution based on Gigabit Ethernet, Gigabit-EtherMAC, is proposed. This solution employs master/Slave structure and the Slave Node based on field programmable gate array (FPGA) manages the communication cycle, which greatly reduces the real-time demand for the master Node. In this paper, a summation frame cut-through mechanism is employed to reduce communication cycle. A relative distributed clock mechanism is also proposed to realize accurate synchronization between Slave Nodes. Experiments show that the communication period is stable, the forwarding delay of Slave Nodes can be as low as 384 nanoseconds, and the synchronization jitter of Slave Node is less than 100 nanoseconds when the standard PC is employed as the master Node.

  • A Hardware Independent Real-time Ethernet for Motion Control Systems
    International Journal of Computers Communications & Control, 2015
    Co-Authors: Ji Shuai, Chengrui Zhang, Ke Wang
    Abstract:

    Ethernet for Manufacture Automation Control (EtherMAC) is a new kind of real-time Ethernet used in motion control systems. It adopts a line topology with a standard industrial computer based master Node and field-programmable-gate-array based Slave Nodes. EtherMAC employs one Slave Node to manage cycle communication and clock synchronization, so the real-time demand for its master Node can be greatly reduced and dedicated hardware is no longer mandatory. Its distributed clock compensation mechanism can get synchronization accuracy in nanosecond order. The advantages of industrial computer and field programmable-gate-array are combined with EtherMAC, so that high control performance can be achieved.

  • Frame forward mechanism of a real-time Ethernet
    2013 IEEE International Conference on Signal Processing Communication and Computing (ICSPCC 2013), 2013
    Co-Authors: Ji Shuai, Dong Jin, Chengrui Zhang
    Abstract:

    A kind of high efficient frame forward mechanism in line topology real-time Ethernet is proposed in this paper. The control data and state data of the networked control system are separated into downstream and upstream frame respectively. The downstream frame that conveys control data from master Node to Slave Nodes are processed in two parallel channels, the first channel is responsible for extracting its control data, and the other one is in charge of forwarding the frame. The upstream frame which conveys the sate data from Slave Nodes to master Node are forwarded and modified on line. The delivery time can be greatly reduced with this mechanism, because the forward delay of each Slave Node is reduced. This method is implemented on Field Programmable Gate Array (FPGA) finally, and the experiment results shows that forward delay in nanoseconds order can be achieved with this mechanism.

  • Design and application of a real-time industrial Ethernet protocol under Linux using RTAI
    International Journal of Computer Integrated Manufacturing, 2013
    Co-Authors: Chengrui Zhang, R. Liu
    Abstract:

    Nowadays, Ethernet networks have been extended down into the field of automation control from the upper planning and scheduling level, which caused the generation of a new form of communication using real-time industrial Ethernet fieldbus. This paper presents a feasible Ethernet-based real-time feildbus scenario for industrial automation control systems. It endeavours to gain high performance in general synchronisation real-time control systems with common hardware and software resources. For this purpose, a master-Slave pattern is adopted in constructing the communication protocol. The Slave Nodes are developed based on universal FPGA and ARM chips, and the first Slave Node is in charge of precise cyclic timing and synchronisation among all Slave Nodes with time resolution of 20 nanoseconds. The master protocol stack is developed under Linux using Real Time Application Interface RTAI, which not only provides application interface for user programs but also is responsible for exchanging process data with Slave Nodes in real time. A case study of merging this fieldbus into EMC2 to control a three-axis milling machine is also discussed and implemented. The experiment results show that this industrial Ethernet fieldbus platform completely meets the demand of open industrial automation control application.

  • development of industrial ethernet windows driver for motion control system
    Advanced Materials Research, 2011
    Co-Authors: Lin Yang, Chengrui Zhang
    Abstract:

    An industrial Ethernet based motion control system is presented in the paper. The first Slave Node in the line topology is responsible for the precise cyclic communication, and it will reduce the real-time requirement on the main controller. The communication protocol is implemented as Windows NDIS protocol driver, and provides higher priority than normal user mode application. In addition, the development environment and process are also discussed, through which the developer can debug the system software at a single computer in both simulated mode and real mode.

C Toumazou - One of the best experts on this subject based on the ideXlab platform.

  • energy efficient medium access protocol for wireless medical body area sensor networks
    IEEE Transactions on Biomedical Circuits and Systems, 2008
    Co-Authors: O Omeni, A Wong, A J Burdett, C Toumazou
    Abstract:

    This paper presents a novel energy-efficient MAC Protocol designed specifically for wireless body area sensor networks (WBASN) focused towards pervasive healthcare applications. Wireless body area networks consist of wireless sensor Nodes attached to the human body to monitor vital signs such as body temperature, activity or heart-rate. The network adopts a master-Slave architecture, where the body-worn Slave Node periodically sends sensor readings to a central master Node. Unlike traditional peer-to-peer wireless sensor networks, the Nodes in this biomedical WBASN are not deployed in an ad hoc fashion. Joining a network is centrally managed and all communications are single-hop. To reduce energy consumption, all the sensor Nodes are in standby or sleep mode until the centrally assigned time slot. Once a Node has joined a network, there is no possibility of collision within a cluster as all communication is initiated by the central Node and is addressed uniquely to a Slave Node. To avoid collisions with nearby transmitters, a clear channel assessment algorithm based on standard listen-before-transmit (LBT) is used. To handle time slot overlaps, the novel concept of a wakeup fallback time is introduced. Using single-hop communication and centrally controlled sleep/wakeup times leads to significant energy reductions for this application compared to more ldquoflexiblerdquo network MAC protocols such as 802.11 or Zigbee. As duty cycle is reduced, the overall power consumption approaches the standby power. The protocol is implemented in hardware as part of the Sensiumtrade system-on-chip WBASN ASIC, in a 0.13- mum CMOS process.

Marco Vieira - One of the best experts on this subject based on the ideXlab platform.

  • COMPSAC - Leveraging 24/7 Availability and Performance for Distributed Real-Time Data Warehouses
    2012 IEEE 36th Annual Computer Software and Applications Conference, 2012
    Co-Authors: Ricardo Jorge Santos, Jorge Bernardino, Marco Vieira
    Abstract:

    Real-time Data Warehouses (DWs) must be able to deal with continuous updates while ensuring 24/7 availability. To improve their performance, distributing data using round-robin algorithms on clusters of shared-nothing machines is normally used. This paper proposes a solution for distributed DW databases that ensures its continuous availability and deals with frequent data loading requirements, while adding small performance overhead. We use a data striping and replication architecture to distribute portions of each fact table among pairs of Slave Nodes, where each Slave Node is an exact replica of its partner. This allows balancing query execution and replacing any defective Node, ensuring the system's continuous availability. The size of each portion in a given Node depends on its individual features, namely performance benchmark measures and dedicated database RAM. The estimated cost for executing each query workload in each Slave Node is also used for balancing query performance. We include experiments using the TPC-H decision support benchmark to evaluate the scalability of the proposed solution and show that it outperforms standard round-robin distributed DW setups.

O Omeni - One of the best experts on this subject based on the ideXlab platform.

  • energy efficient medium access protocol for wireless medical body area sensor networks
    IEEE Transactions on Biomedical Circuits and Systems, 2008
    Co-Authors: O Omeni, A Wong, A J Burdett, C Toumazou
    Abstract:

    This paper presents a novel energy-efficient MAC Protocol designed specifically for wireless body area sensor networks (WBASN) focused towards pervasive healthcare applications. Wireless body area networks consist of wireless sensor Nodes attached to the human body to monitor vital signs such as body temperature, activity or heart-rate. The network adopts a master-Slave architecture, where the body-worn Slave Node periodically sends sensor readings to a central master Node. Unlike traditional peer-to-peer wireless sensor networks, the Nodes in this biomedical WBASN are not deployed in an ad hoc fashion. Joining a network is centrally managed and all communications are single-hop. To reduce energy consumption, all the sensor Nodes are in standby or sleep mode until the centrally assigned time slot. Once a Node has joined a network, there is no possibility of collision within a cluster as all communication is initiated by the central Node and is addressed uniquely to a Slave Node. To avoid collisions with nearby transmitters, a clear channel assessment algorithm based on standard listen-before-transmit (LBT) is used. To handle time slot overlaps, the novel concept of a wakeup fallback time is introduced. Using single-hop communication and centrally controlled sleep/wakeup times leads to significant energy reductions for this application compared to more ldquoflexiblerdquo network MAC protocols such as 802.11 or Zigbee. As duty cycle is reduced, the overall power consumption approaches the standby power. The protocol is implemented in hardware as part of the Sensiumtrade system-on-chip WBASN ASIC, in a 0.13- mum CMOS process.

  • energy efficient medium access protocol for wireless medical body area sensor networks
    2007 4th IEEE EMBS International Summer School and Symposium on Medical Devices and Biosensors, 2007
    Co-Authors: O Omeni, O Eljamaly, Alison Burdett
    Abstract:

    This paper presents a novel energy-efficient MAC Protocol designed specifically for wireless body area sensor networks (WBASN) focused towards pervasive healthcare applications. Wireless body area networks consist of wireless sensor Nodes attached to the human body to monitor vital signs such as body temperature, activity or heart-rate. The network adopts a master-Slave architecture, where the body-worn Slave Node periodically sends sensor readings to a central master Node. Unlike traditional peer-to-peer wireless sensor networks, the Nodes in this biomedical WBASN are not deployed in an ad hoc fashion. Joining a network is centrally managed and all communications are single-hop. To reduce energy consumption, all the sensor Nodes are in standby or sleep mode until the centrally assigned time slot. Once a Node has joined a network, there is no possibility of collision within a cluster as all communication is initiated by the central Node and is addressed uniquely to a Slave Node. To avoid collisions with nearby transmitters, a clear channel assessment algorithm based on standard listen-before-transmit (LBT) is used. To handle time slot overlaps, the novel concept of a wakeup fallback time is introduced. Using single-hop communication and centrally controlled sleep/wakeup times leads to significant energy reductions for this application compared to more 'flexible' network MAC protocols such as 802.11 or Zigbee. With longer sleep times, the overall power consumption approaches the standby power. The protocol is implemented in hardware as part of the Sensiumtrade system-on-chip WBASN ASIC, in a 0.13 um CMOS process.

D. Richard Brown - One of the best experts on this subject based on the ideXlab platform.

  • ICASSP - A software-defined radio implementation of timestamp-free network synchronization
    2017 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2017
    Co-Authors: Mitchell W.s. Overdick, Andrew G. Klein, Joseph E. Canfield, D. Richard Brown
    Abstract:

    This paper describes a real-time implementation of timestamp-free network synchronization using RF signaling between a master and Slave Node. Rather than conventional approaches of exchanging digital timestamps through a dedicated synchronization protocol, timestamp-free synchronization is performed implicitly at the physical layer through timing of a master Node's responses to a Slave Node. This approach was implemented in C++ on a pair of Ettus USRP E310 software defined radios, and extends a previous implementation at audio frequencies using acoustic hardware. Experimental results using modulated sinc pulses demonstrate synchronization accuracy less than 12% of the sampling period. The results confirm previous theoretical studies suggesting that the timestamp-free synchronization approach accurately accounts for propagation delay, frequency offset, and stochastic drift.

  • ACSSC - A real-time implementation of precise timestamp-free network synchronization
    2015 49th Asilomar Conference on Signals Systems and Computers, 2015
    Co-Authors: Stefan Gvozdenovic, Alexander Ryan, Radu David, D. Richard Brown, Andrew G. Klein
    Abstract:

    This paper describes a real-time implementation of precise synchronization between a master and Slave Node. The Nodes were both implemented on separate Texas Instruments DSP boards with real-time software implemented in C. Timestamp-free synchronization is performed implicitly through the timing of the master Node's responses to the Slave Node. The Slave Node tracks and predicts the master Node's clock through precise time of arrival estimation and Kalman filtering of the estimates. Experimental results demonstrate the Slave Node is able to consistently predict the master Node's clock offset to within a few nanoseconds over one second prediction intervals.

  • Precise timestamp-free network synchronization
    2013 47th Annual Conference on Information Sciences and Systems (CISS), 2013
    Co-Authors: D. Richard Brown, Andrew G. Klein
    Abstract:

    This paper describes an approach to master/Slave network synchronization based on bidirectional message exchanges without the use of timestamps. Rather than the usual approach of exchanging digital timestamps through a dedicated synchronization protocol, an approach is described in which synchronization information is conveyed implicitly at the physical layer through the timing of the master Node?s responses to the Slave Nodes. This approach can reduce overhead and allow the embedding of synchronization functions in existing network traffic. A timestamp-free synchronization protocol is described and its performance is quantified in the presence of delay estimation error and stochastic local oscillator dynamics. A filtering framework is also developed to allow each Slave Node to accurately infer and correct local clock drifts from multiple noisy clock offset estimates. Based on fundamental delay estimation bounds for narrowband signals, numerical results show that synchronization among the Slave Nodes can be achieved quickly and that the resulting steady-state accuracy can be sufficient to support distributed transmission techniques requiring carrier phase alignment, e.g. distributed beamforming.