The Experts below are selected from a list of 69765 Experts worldwide ranked by ideXlab platform

Gregory Hackmann - One of the best experts on this subject based on the ideXlab platform.

  • Real-World Empirical Studies on Multi-Channel Reliability and Spectrum Usage for Home-Area Sensor Networks
    IEEE Transactions on Network and Service Management, 2013
    Co-Authors: Mo Sha, Gregory Hackmann
    Abstract:

    Home area networks (HANs) consisting of wireless sensors have emerged as the enabling technology for important applications such as smart energy. These applications impose unique network management constraints, requiring low data rates but high network reliability in the face of unpredictable wireless environments. This paper presents two in-depth empirical studies on wireless Channels in real homes, providing key design guidelines for meeting the network management constraints of HAN applications. The spectrum study analyzes spectrum usage in the 2.4 GHz band where HANs based on the IEEE 802.15.4 standard must coexist with existing wireless devices. We characterize the ambient wireless environment in six apartments through passive spectrum analysis across the entire 2.4 GHz band over seven days in each apartment. We find that the wireless conditions in these residential environments are much more complex and varied than in a typical office environment. Moreover, while 802.11 signals play a significant role in spectrum usage, there also exists non-negligible noise from non-802.11 devices. The multi-Channel Link study measures the reliability of different 802.15.4 Channels through active probing with motes in ten apartments. We find that there is not always a persistently reliable Channel over 24 hours, and that Link reliability does not exhibit cyclic behavior at daily or weekly timescales. Nevertheless, reliability can be maintained through infrequent Channel hopping, suggesting dynamic Channel hopping as a key tool for meeting the network management requirements of HAN applications. Our empirical studies provide important guidelines and insights in designing HANs for residential environments.

Christos Verikoukis - One of the best experts on this subject based on the ideXlab platform.

  • highly reliable energy saving mac for wireless body sensor networks in healthcare systems
    IEEE Journal on Selected Areas in Communications, 2009
    Co-Authors: Begonya Otal, Luis Alonso, Christos Verikoukis
    Abstract:

    Wireless body sensor networks (BSNs) in healthcare systems operate under conflicting requirements. These are the maintenance of the desired reliability and message latency of data transmissions, while simultaneously maximizing battery lifetime of individual body sensors. In doing so, the characteristics of the entire system, including physical, medium access control (MAC), and application layers have to be considered. The aim of this paper is to develop a new MAC model for BSNs to fulfill all these specific rigorous requirements under realistic medical settings. For that purpose, a novel cross-layer fuzzy-rule scheduling algorithm and energy-aware radio activation policies are introduced. The main idea is to integrate a fuzzy-logic system in each body sensor to deal with multiple cross-layer input variables of diverse nature in an independent manner. By being autonomously aware of their current condition, body sensors are able to demand a "collision-free" time slot, whenever they consider it strictly required (e.g. high system packet delay or low body sensor residual battery lifetime). Similarly, they may refuse to transmit, if there is a bad Channel Link, thus permitting another body sensor to do so. This results in improving the system overall performance. The proposed MAC model is evaluated by computer simulations in terms of quality of service and energy consumption under specific healthcare scenarios.

Gao Nana - One of the best experts on this subject based on the ideXlab platform.

  • Design and Implementation of High-performance Optical-interconnection Cluster Network Adapter
    Computer Engineering, 2006
    Co-Authors: Gao Nana
    Abstract:

    With the performance increasing of single terminal of cluster system in network,bandwidth and reliability of cluster network have become primary factors for system performance.An architecture of high-performance optical-interconnect cluster network adapter is presented,and implemented in XC2VP20 FPGA chip of Xilinx Corp.The exploration to overcome bottleneck of high-performance cluster interconnect Link has been done.The test result demonstrates that the bandwidth of DDR memory interface reaches to 1 600MB/s,and that the highest velocity in single-Channel Link reaches to 2.5Gb/s.

Yuchee Tseng - One of the best experts on this subject based on the ideXlab platform.

  • joint multi Channel Link layer and multi path routing design for wireless mesh networks
    IEEE International Conference Computer and Communications, 2007
    Co-Authors: Waihong Tarn, Yuchee Tseng
    Abstract:

    In recent years, the wireless mesh network (WMN) attracts the interest of many people as a new broadband Internet access technology. However, increasing throughput is still an open and challenging research issue. One potential solution is to enable transceivers to utilize multiple Channels dynamically. However, most of existing works do not consider the routing issue, and trivially use some popular single-path routing protocols like AODV and DSR. In this paper, we exploit the benefit of multi-path routing in multi-Channel WMNs from the aspect of end-to-end throughput. Between medium access control and network layers, we propose a novel protocol named Joint Multi-Channel and Multi-path control (JMM) which combines multi-Channel Link layer with multi-path routing. Dividing time into slots, JMM coordinates Channel usage among slots and schedules traffic flows on dual paths. Our scheme efficiently and intelligently decomposes contending traffics over different Channels, different time, and different paths, and hence leads to significant throughput improvement. To the best of our knowledge, this is the first work discussing the joint design of multi-Channel control and multi-path routing for WMNs.

  • INFOCOM - Joint Multi-Channel Link Layer and Multi-Path Routing Design for Wireless Mesh Networks
    IEEE INFOCOM 2007 - 26th IEEE International Conference on Computer Communications, 2007
    Co-Authors: Waihong Tarn, Yuchee Tseng
    Abstract:

    In recent years, the wireless mesh network (WMN) attracts the interest of many people as a new broadband Internet access technology. However, increasing throughput is still an open and challenging research issue. One potential solution is to enable transceivers to utilize multiple Channels dynamically. However, most of existing works do not consider the routing issue, and trivially use some popular single-path routing protocols like AODV and DSR. In this paper, we exploit the benefit of multi-path routing in multi-Channel WMNs from the aspect of end-to-end throughput. Between medium access control and network layers, we propose a novel protocol named Joint Multi-Channel and Multi-path control (JMM) which combines multi-Channel Link layer with multi-path routing. Dividing time into slots, JMM coordinates Channel usage among slots and schedules traffic flows on dual paths. Our scheme efficiently and intelligently decomposes contending traffics over different Channels, different time, and different paths, and hence leads to significant throughput improvement. To the best of our knowledge, this is the first work discussing the joint design of multi-Channel control and multi-path routing for WMNs.

Xia Zhao - One of the best experts on this subject based on the ideXlab platform.

  • interannual climate variability over the tropical pacific ocean induced by the indian ocean dipole through the indonesian throughflow
    Journal of Climate, 2013
    Co-Authors: Dongliang Yuan, Hui Zhou, Xia Zhao
    Abstract:

    The authors' previous dynamical study has suggested a Link between the Indian and Pacific Ocean interannual climate variations through the transport variations of the Indonesian Throughflow. In this study, the consistency of this oceanic Channel Link with observations is investigated using correlation analyses of observed ocean temperature, sea surface height, and surface wind data. The analyses show significant lag correlations between the sea surface temperature anomalies (SSTA) in the southeastern tropical Indian Ocean in fall and those in the eastern Pacific cold tongue in the following summer through fall seasons, suggesting potential predictability of ENSO events beyond the period of 1 yr. The dynamics of this teleconnection seem not through the atmospheric bridge, because the wind anomalies in the far western equatorial Pacific in fall have insignificant correlations with the cold tongue anomalies at time lags beyond one season. Correlation analyses between the sea surface height anomalies (SSHA) in the southeastern tropical Indian Ocean and those over the Indo-Pacific basin suggest eastward propagation of the upwelling anomalies from the Indian Ocean into the equatorial Pacific Ocean through the Indonesian Seas. Correlations in the subsurface temperature in the equatorial vertical section of the Pacific Ocean confirm the propagation. In spite of the limitation of the short time series of observations available, the study seems to suggest that the ocean Channel connection between the two basins is important for the evolution and predictability of ENSO.