The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Zhiqiang Zheng - One of the best experts on this subject based on the ideXlab platform.
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ICRA - Combinatorial Bids based Multi-robot Task Allocation Method
Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 1Co-Authors: Liu Lin, Zhiqiang ZhengAbstract:How to coordinate several robots to cooperatively accomplish relatively complex tasks is not an easy issue. This paper presents a combinatorial bids based multi-robot task allocation method. The proposed method provides an Explicit Cooperation mechanism to the bidding robots so that they can form a group to bid for complex tasks. Some carefully designed simulations indicate that this method is more efficient than the typical auction based one in some situations.
Nuno M F Ferreira - One of the best experts on this subject based on the ideXlab platform.
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Marsupial teams of robots: deployment of miniature robots for swarm exploration under communication constraints
Robotica, 2014Co-Authors: Micael S Couceiro, David Portugal, Rui P Rocha, Nuno M F FerreiraAbstract:Mobile Ad hoc Networks have attracted much attention in the last years, since they allow the coordination and Cooperation between agents belonging to a multi-robot system. However, initially deploying autonomously a wireless sensor robot network in a real environment has not taken the proper attention. Moreover, maintaining the connectivity between agents in real and complex environments is an arduous task since the strength of the connection between two nodes (i.e., robots) can change rapidly in time or even disappear. This paper compares two autonomous and realistic marsupial strategies for initial deployment in unknown scenarios, in the context of swarm exploration: Random and Extended Spiral of Theodorus . These are based on a hierarchical approach, in which exploring agents, named scouts , are autonomously deployed through Explicit Cooperation with supporting agents, denoted as rangers . Experimental results with a team of heterogeneous robots are conducted using both real and virtual robots. Results show the effectiveness of the methods, using a performance metric based on dispersion. Conclusions drawn in this work pave the way for a whole series of possible new approaches.
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IROS - Initial deployment of a robotic team - a hierarchical approach under communication constraints verified on low-cost platforms
2012 IEEE RSJ International Conference on Intelligent Robots and Systems, 2012Co-Authors: Micael S Couceiro, David Portugal, Rui P Rocha, Carlos M. Figueiredo, Nuno M F FerreiraAbstract:In most real multi-robot applications, e.g., search-and-rescue, cooperative robots have to fulfill their tasks while driving and communicating among themselves without the aid of a network infrastructure. However, initially deploying autonomously a wireless sensor robot network in a real environment has not taken the proper attention. This paper presents an autonomous and realistic initial deployment strategy, based on a hierarchical approach, in which exploring agents, denoted as scouts, are autonomously deployed through Explicit Cooperation with supporting agents, denoted as rangers. To evaluate the initial deployment strategy proposed, experimental results with a team of heterogeneous robots are conducted using modified low-cost platforms previously developed by the authors. Preliminary results show the effectiveness of the method and pave the way for a whole series of possible new approaches.
Brian Trammell - One of the best experts on this subject based on the ideXlab platform.
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Requirements for the design of a Substrate Protocol for User Datagrams (SPUD)
2016Co-Authors: Mirja Kühlewind, Brian TrammellAbstract:We have identified the potential need for a UDP-based encapsulation protocol to allow Explicit Cooperation with middleboxes while using new, encrypted transport protocols. This document proposes an initial set of requirements for such a protocol, and discusses tradeoffs to be made in further refining these requirements.
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Use Cases for a Substrate Protocol for User Datagrams (SPUD)
2016Co-Authors: Mirja Kühlewind, Brian TrammellAbstract:This document identifies use cases for Explicit Cooperation between endpoints and middleboxes in the Internet under endpoint control. These use cases range from relatively low level applications (improving the ability for UDP-based protocols to traverse firewalls) through support for new transport services (in-flow prioritization for graceful in-network degradation of media streams). They are intended to provide background for deriving the requirements for a Substrate Protocol for User Datagrams (SPUD), as discussed at the IAB Stack Evolution in a Middlebox Internet (SEMI) workshop in January 2015 and the SPUD BoF session at IETF 92 in March 2015.
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Architectural Considerations for Transport Evolution with Explicit Path Cooperation
2015Co-Authors: Brian TrammellAbstract:The IAB Stack Evolution in a Middlebox Internet (SEMI) workshop in Zurich in January 2015 and the follow-up Substrate Protocol for User Datagrams (SPUD) BoF session at the IETF 92 meeting in Dallas in March 2015 identified the potential need for a UDP-based encapsulation to allow Explicit Cooperation with middleboxes while using encryption at the transport layer and above to protect user payload and metadata from inspection and interference. This document proposes a set of architectural considerations for such approaches.
Adam Wolisz - One of the best experts on this subject based on the ideXlab platform.
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Null-While-Talk: Interference nulling for improved inter-technology coexistence in LTE-U and WiFi networks
Pervasive and Mobile Computing, 2019Co-Authors: Suzan Bayhan, Anatolij Zubow, Piotr Gawlowicz, Adam WoliszAbstract:Abstract A recent proposal known as unlicensed LTE offers cost-effective capacity extension to the cellular network operators in which LTE operators bundle the unlicensed spectrum in 5 GHz UNII bands with their licensed spectrum via carrier aggregation. But, unlicensed spectrum requires coexistence among the networks operating in the same spectrum, e.g., IEEE 802.11 (WiFi) networks at 5 GHz. While WiFi implements Listen-Before-Talk (LBT) and is therefore coexistence-friendly, LTE-Unlicensed (LTE-U) lacks such capability as it is not designed with shared spectrum access in mind. Hence, LTE has a potential to seriously harm WiFi. Prior works suggest forcing LTE-U to separate its transmission in either frequency, time, or space, and without directly collaborating with the WiFi networks. Contrary to these schemes, we introduce an Explicit Cooperation between neighboring LTE-U and WiFi networks. We propose Null-While-Talk(NWT) which suggests that LTE-U BSs employ MIMO signal processing to create coexistence gaps in space domain in addition to the time domain gaps by means of cross-technology interference nulling towards WiFi nodes in the interference range. In return, LTE-U can increase its own airtime utilization while trading off slightly its gain from MIMO. First, we present simulation results indicating that such Cooperation offers benefits to both networks, WiFi and LTE-U, in terms of improved throughput and decreased channel access delay. Moreover, we present Xzero which implements NWT in a practical setting where the LTE-U BS lacks channel state and location information about the WiFi stations to be nulled. Xzero overcomes this challenge by performing an intelligent null search guided by constant feedback from the WiFi node on the null directions being tested. Our Xzero prototype implemented on SDR and COTS WiFi hardware shows the feasibility of our proposal.
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WOWMOM - Coexistence Gaps in Space via Interference Nulling for LTE-U/WiFi Coexistence
2018 IEEE 19th International Symposium on "A World of Wireless Mobile and Multimedia Networks" (WoWMoM), 2018Co-Authors: Suzan Bayhan, Anatolij Zubow, Adam WoliszAbstract:To avoid the foreseeable spectrum crunch, LTE operators have started to explore the option to directly use the underutilized unlicensed spectrum in 5 GHz UNII bands being mainly used by IEEE 802.11 (WiFi). However, as LTE is not designed with shared spectrum access in mind, it has a potential to seriously harm Wi-Fi, Currently suggested solutions focus on forcing LTE-U to introduce coexistence gaps in either frequency, time, or space domain, and are addressing the coexistence only indirectly due to the lack of coordination among the coexisting WiFi and LTE-U networks. Contrary to these schemes, our proposal introduces Explicit Cooperation between neighboring LTE-U and WiFi networks. We suggest that LTE-U BSs equipped with multiple antennas can create coexistence gaps in space domain in addition to the time domain gaps by means of cross-technology interference nulling towards WiFi nodes in the interference range. In return, LTE-U can increase its own airtime utilization while trading off slightly its antenna diversity. We demonstrate that such Cooperation offers benefits to both WiFi and LTE-U in terms of improved throughput and decreased channel access delay. More specifically, system-level simulations reveal a throughput gain up to 221% for LTE-U network and up to 44% for WiFi network depending on the setting, e.g., distance between the two cells, number of LTE antennas, and WiFi nodes in the LTE-U BS neighborhood. Our approach provides significant benefits especially for moderate separation distances between LTE-U/WiFi cells where interference from a neighboring network might be severe due to the hidden network problem.
Liu Lin - One of the best experts on this subject based on the ideXlab platform.
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ICRA - Combinatorial Bids based Multi-robot Task Allocation Method
Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 1Co-Authors: Liu Lin, Zhiqiang ZhengAbstract:How to coordinate several robots to cooperatively accomplish relatively complex tasks is not an easy issue. This paper presents a combinatorial bids based multi-robot task allocation method. The proposed method provides an Explicit Cooperation mechanism to the bidding robots so that they can form a group to bid for complex tasks. Some carefully designed simulations indicate that this method is more efficient than the typical auction based one in some situations.
