The Experts below are selected from a list of 9114 Experts worldwide ranked by ideXlab platform

Shuzo Kato - One of the best experts on this subject based on the ideXlab platform.

  • NACRP: A Connectivity Protocol for Star Topology Wireless Sensor Networks
    IEEE Wireless Communications Letters, 2016
    Co-Authors: Leonardo Goratti, Tuncer Baykas, Tinku Rasheed, Shuzo Kato
    Abstract:

    Wireless sensor networks (WSNs) are an ever growing field of applications and one constituent of the future Internet-of-Things (IoT). In this work, we investigate Star Topology sensor networks compliant with the recent IEEE 802.15.4k standard in which sensors could fail to report sensing information to the access point (AP) due to temporary obstructions that clutter the link with the AP. The contribution of this work is twofold. First, we study general connectivity requirements in relay networks. Second, to restore connectivity and to recover from information loss, we propose the neighbor-assisted connectivity recovery protocol (NACRP), which automatically selects a subset of sensor nodes to act as relays for those which lack connectivity with the AP. In our study, we rely on the tool of stochastic geometry and in particular, on Poisson point processes to seek the tradeoff, which arises from the selection of a subset of relay nodes and the necessary transmitted power that relays need to use to restore network connectivity.

  • on the spectrum efficiency of mesh and Star Topology wide area wireless sensor networks
    Personal Indoor and Mobile Radio Communications, 2014
    Co-Authors: Tuncer Baykas, Tinku Rasheed, Leonardo Goratti, Shuzo Kato
    Abstract:

    Wireless sensor networks (WSNs) are meant to monitor natural and man-made phenomena, made of simple low cost sensors interconnected via low data rate communication links to survey wide areas. In this paper, we investigate the trade-off arising from spectrum occupation and packet delivery time in professionally installed wide area WSNs (WA-WSNs). We study two types of network topologies, namely Star and mesh topologies, based on the recent IEEE 802.15.4k and multi-channel multi-radio IEEE 802.15.4g standards, respectively. We perform extensive packet level simulations of the mesh Topology network, while keeping the Star network as a benchmark. Our contribution is threefold. First, we address connectivity in the mesh network by deploying additional relay nodes, when necessary, to enable also each node with at least two independent route alternatives. Second, our simulation results show that the mesh Topology requires 20% more spectrum to deliver the whole set of sensed data to the traffic sink compared with the Star Topology network under delivery time constraints. Finally, we show that only 10% of the nodes in the mesh network actually need additional spectrum and multiple radio transceivers to keep the delay bounded by that of the Star Topology.

  • PIMRC - On the spectrum efficiency of mesh and Star Topology wide area wireless sensor networks
    2014 IEEE 25th Annual International Symposium on Personal Indoor and Mobile Radio Communication (PIMRC), 2014
    Co-Authors: Tuncer Baykas, Tinku Rasheed, Leonardo Goratti, Shuzo Kato
    Abstract:

    Wireless sensor networks (WSNs) are meant to monitor natural and man-made phenomena, made of simple low cost sensors interconnected via low data rate communication links to survey wide areas. In this paper, we investigate the trade-off arising from spectrum occupation and packet delivery time in professionally installed wide area WSNs (WA-WSNs). We study two types of network topologies, namely Star and mesh topologies, based on the recent IEEE 802.15.4k and multi-channel multi-radio IEEE 802.15.4g standards, respectively. We perform extensive packet level simulations of the mesh Topology network, while keeping the Star network as a benchmark. Our contribution is threefold. First, we address connectivity in the mesh network by deploying additional relay nodes, when necessary, to enable also each node with at least two independent route alternatives. Second, our simulation results show that the mesh Topology requires 20% more spectrum to deliver the whole set of sensed data to the traffic sink compared with the Star Topology network under delivery time constraints. Finally, we show that only 10% of the nodes in the mesh network actually need additional spectrum and multiple radio transceivers to keep the delay bounded by that of the Star Topology.

  • a Star Topology sensor network system for agriculture using 802 15 4k standard
    Personal Indoor and Mobile Radio Communications, 2013
    Co-Authors: Yasutaka Tada, Shuzo Kato
    Abstract:

    This paper introduces a sensor network with Star Topology for agriculture applications in Japan. The system is based on Direct Sequence Spread Spectrum (DSSS) PHY of the IEEE 802.15.4k standard. It will operate It can operate in 920-928 MHz band with MHz bandwidth according to Japanase regulations. According to our analysis it has a range of 20 kms in line of sight and 5 kms in none-line-of-sight environment. In addition, we investigated the impact of co-channel interference (CCI) from a smart utility network transmitter with 200 kHz bandwidth based on IEEE 802.15.4g standard specifications to our system. Our results indicate that at desired to undesired signal (D/U) ratios more than 6.8 dB, our network can operate successfully at an Eb/N0 of 5dB without the need of spreading. A spreading factor of 1024 protect 802.15.4 link up to D/U ratios of -55dB and sensor system can reduce the area that 802.15.4g effectively interfere by 106 times compared with no spreading.

  • PIMRC Workshops - A Star-Topology sensor network system for agriculture using 802.15.4k standard
    2013 IEEE 24th International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC Workshops), 2013
    Co-Authors: Yasutaka Tada, Shuzo Kato
    Abstract:

    This paper introduces a sensor network with Star Topology for agriculture applications in Japan. The system is based on Direct Sequence Spread Spectrum (DSSS) PHY of the IEEE 802.15.4k standard. It will operate It can operate in 920-928 MHz band with MHz bandwidth according to Japanase regulations. According to our analysis it has a range of 20 kms in line of sight and 5 kms in none-line-of-sight environment. In addition, we investigated the impact of co-channel interference (CCI) from a smart utility network transmitter with 200 kHz bandwidth based on IEEE 802.15.4g standard specifications to our system. Our results indicate that at desired to undesired signal (D/U) ratios more than 6.8 dB, our network can operate successfully at an Eb/N0 of 5dB without the need of spreading. A spreading factor of 1024 protect 802.15.4 link up to D/U ratios of -55dB and sensor system can reduce the area that 802.15.4g effectively interfere by 106 times compared with no spreading.

Jan Torin - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of fault handling of the time triggered architecture with bus and Star Topology
    Dependable Systems and Networks, 2003
    Co-Authors: A Ademaj, H Sivencrona, G Bauer, Jan Torin
    Abstract:

    Arbitrary faults of a single node In a time-triggered architecture (TTA) bus Topology system may cause error propagation to correct nodes and may lead to inconsistent system states. This has been observed in validation work using software implemented fault injection (SWIFI) and heavy-ion fault injection techniques in a TTA cluster. In a TTA system, the membership and the clique avoidance algorithms detect state inconsistencies and force the nodes that do not have the same state with the state of majority of nodes, to reStart. Changing the interconnection structure of the cluster to a Star Topology allows the use of Star couplers that will isolate faults of a node, thus guaranteeing consistency, even in the presence of arbitrary node failures. The same SWIFI and heavy-ion fault injection experiments that caused error propagation in bus-based TTA clusters, were performed in the Star configuration. No error propagation was observed in a TTA system with the Star Topology during the execution of SWIFI and heavy-ion experiments.

  • DSN - Evaluation of fault handling of the time-triggered architecture with bus and Star Topology
    2003 International Conference on Dependable Systems and Networks 2003. Proceedings., 1
    Co-Authors: A Ademaj, H Sivencrona, G Bauer, Jan Torin
    Abstract:

    Arbitrary faults of a single node In a time-triggered architecture (TTA) bus Topology system may cause error propagation to correct nodes and may lead to inconsistent system states. This has been observed in validation work using software implemented fault injection (SWIFI) and heavy-ion fault injection techniques in a TTA cluster. In a TTA system, the membership and the clique avoidance algorithms detect state inconsistencies and force the nodes that do not have the same state with the state of majority of nodes, to reStart. Changing the interconnection structure of the cluster to a Star Topology allows the use of Star couplers that will isolate faults of a node, thus guaranteeing consistency, even in the presence of arbitrary node failures. The same SWIFI and heavy-ion fault injection experiments that caused error propagation in bus-based TTA clusters, were performed in the Star configuration. No error propagation was observed in a TTA system with the Star Topology during the execution of SWIFI and heavy-ion experiments.

Michel Misson - One of the best experts on this subject based on the ideXlab platform.

  • Topology discovery delay evaluation in Star Topology network with switched beam antenna sink
    Ad Hoc Networks, 2019
    Co-Authors: Guereguin Der Sylvestre Sidibe, Raphael Bidaud, Marie Francoise Servajean, Hamadoun Tall, Michel Misson
    Abstract:

    Wireless Sensor Networks (WSNs) are useful in several application domains. They are often used for data gathering in an interested area. The popularity of WSNs is due to their ease of deployment and auto-configuration capabilities. A WSN network is composed by several sensor nodes that must cooperate and build the network where each node is in range of at least one other node. In Star network Topology, the sink node is in range of the all others and the communication from each node to the sink is assumed to be a single hop. So, the sink node can discover all the others nodes around it belonging to the Star Topology.

  • ADHOC-NOW - Topology Discovery Delay Evaluation in Star Topology Network with Switched-Beam Antenna Sink
    Ad-Hoc Mobile and Wireless Networks, 2019
    Co-Authors: Guereguin Der Sylvestre Sidibe, Raphael Bidaud, Marie Francoise Servajean, Hamadoun Tall, Michel Misson
    Abstract:

    Wireless Sensor Networks (WSNs) are useful in several application domains. They are often used for data gathering in an interested area. The popularity of WSNs is due to their ease of deployment and auto-configuration capabilities. A WSN network is composed by several sensor nodes that must cooperate and build the network where each node is in range of at least one other node. In Star network Topology, the sink node is in range of the all others and the communication from each node to the sink is assumed to be a single hop. So, the sink node can discover all the others nodes around it belonging to the Star Topology.

  • GLOBECOM - Neighborhood Discovery Approach in WSN for Star Topology Using a Switched Beam Antenna
    2019 IEEE Global Communications Conference (GLOBECOM), 2019
    Co-Authors: Guereguin Der Sylvestre Sidibe, Raphael Bidaud, Marie Francoise Servajean, Nadir Hakem, Michel Misson
    Abstract:

    Wireless Sensor Networks (WSNs) are often used for gathering data collected by sensor nodes spread over large monitored areas. Star topologies, having a sink node at their center, are becoming a clear trend when the size of the monitored area allows it. The range of the radio links used, increases due to the decision to use a sub-GHz frequency and/or a particular signal coding that ensures a significant processing gain in the radio link budget. Even though such long-range radio links are beneficial in specific applications, in spite of the low data rate limit, often remains a weakness for application in many domains. Our overall objective is to consider combining the use of a switched-beam antenna only for the sink node of a Star Topology and omnidirectional antennas for wireless sensor nodes, in order to achieve a better balance between Range and Data Rate. When switched- beam antennas are used to equip some nodes, usual medium access methods have to be revised as does the discovery of the neighborhood of the sink. In this paper, we propose a scheme that allows the sink node to discover all its neighboring nodes within a limited timeframe, despite the hidden terminal problem effects worsen by antennas directivity. Index Terms-Star Topology, wireless Sensor Networks, neigh- borhood discovery, MAC protocols, switched beam antenna

A Ademaj - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of fault handling of the time triggered architecture with bus and Star Topology
    Dependable Systems and Networks, 2003
    Co-Authors: A Ademaj, H Sivencrona, G Bauer, Jan Torin
    Abstract:

    Arbitrary faults of a single node In a time-triggered architecture (TTA) bus Topology system may cause error propagation to correct nodes and may lead to inconsistent system states. This has been observed in validation work using software implemented fault injection (SWIFI) and heavy-ion fault injection techniques in a TTA cluster. In a TTA system, the membership and the clique avoidance algorithms detect state inconsistencies and force the nodes that do not have the same state with the state of majority of nodes, to reStart. Changing the interconnection structure of the cluster to a Star Topology allows the use of Star couplers that will isolate faults of a node, thus guaranteeing consistency, even in the presence of arbitrary node failures. The same SWIFI and heavy-ion fault injection experiments that caused error propagation in bus-based TTA clusters, were performed in the Star configuration. No error propagation was observed in a TTA system with the Star Topology during the execution of SWIFI and heavy-ion experiments.

  • DSN - Evaluation of fault handling of the time-triggered architecture with bus and Star Topology
    2003 International Conference on Dependable Systems and Networks 2003. Proceedings., 1
    Co-Authors: A Ademaj, H Sivencrona, G Bauer, Jan Torin
    Abstract:

    Arbitrary faults of a single node In a time-triggered architecture (TTA) bus Topology system may cause error propagation to correct nodes and may lead to inconsistent system states. This has been observed in validation work using software implemented fault injection (SWIFI) and heavy-ion fault injection techniques in a TTA cluster. In a TTA system, the membership and the clique avoidance algorithms detect state inconsistencies and force the nodes that do not have the same state with the state of majority of nodes, to reStart. Changing the interconnection structure of the cluster to a Star Topology allows the use of Star couplers that will isolate faults of a node, thus guaranteeing consistency, even in the presence of arbitrary node failures. The same SWIFI and heavy-ion fault injection experiments that caused error propagation in bus-based TTA clusters, were performed in the Star configuration. No error propagation was observed in a TTA system with the Star Topology during the execution of SWIFI and heavy-ion experiments.

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

  • A Star-Topology dynamic model for multipedal locomotion
    Proceedings of the 36th IEEE Conference on Decision and Control, 1
    Co-Authors: D. Agahi, K. Kreutz-delgado
    Abstract:

    Dynamic analysis and control of robotic systems with more than a few degrees of freedom, taking into account the full dynamics of the system, is a difficult task. Thus, quite often assumptions are made to simplify the dynamics of the system. In this paper we consider robots with a Star-Topology structure and investigate the dynamic interaction of the branches of such a robot when one or more branches are in contact or collision with the environment (thereby forming closed chains). An important example of a Star-Topology system is a multilegged (e.g., bipedal) walking robot, and in this paper we briefly describe an approach for the control of a multilegged walking robot, using dynamic reduction.

  • ICRA - A Star Topology dynamic model for efficient simulation of multilimbed robotic systems
    Proceedings of the 1994 IEEE International Conference on Robotics and Automation, 1
    Co-Authors: D. Agahi, Kenneth Kreutz-delgado
    Abstract:

    Many systems of interest in robotics have a Star Topology structure (multiple serial chains radiating from a common mobile, non-articulated base). In this paper the author utilize the special structure of Star Topology-based robots to develop algorithms useful for simulating such systems. The algorithm can handle a variety of walking, grasping, and contact situations. As a specific example, a multipedal walking system is analyzed. >