The Experts below are selected from a list of 522 Experts worldwide ranked by ideXlab platform
Claire J Tomlin - One of the best experts on this subject based on the ideXlab platform.
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Planning, Fast and Slow: A Framework for Adaptive Real-Time Safe Trajectory Planning
Proceedings - IEEE International Conference on Robotics and Automation, 2018Co-Authors: David Fridovich-keil, Sylvia L. Herbert, Sampada Deglurkar, Jaime F. Fisac, Claire J TomlinAbstract:Motion planning is an extremely well-studied problem in the robotics community, yet existing work largely falls into one of two categories: computationally efficient but with few if any safety guarantees, or able to give stronger guarantees but at high computational cost. This work builds on a recent development called FaSTrack in which a slow offline computation provides a modular safety guarantee for a faster online planner. We introduce the notion of "meta-planning" in which a refined offline computation enables safe switching between different online planners. This provides autonomous systems with the ability to adapt motion plans to a priori unknown environments in real-time as sensor measurements detect new obstacles, and the flexibility to maneuver differently in the presence of obstacles than they would in free space, all while maintaining a strict safety guarantee. We demonstrate the meta-planning algorithm both in simulation and in hardware using a small Crazyflie 2.0 quadrotor.
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FaSTrack: A modular framework for fast and guaranteed safe motion planning
2017 IEEE 56th Annual Conference on Decision and Control CDC 2017, 2018Co-Authors: Sylvia L. Herbert, Soojean Han, Somil Bansal, Jaime F. Fisac, Mo Chen, Claire J TomlinAbstract:Fast and safe navigation of dynamical systems through a priori unknown cluttered environments is vital to many applications of autonomous systems. However, trajectory planning for autonomous systems is computationally intensive, often requiring simplified dynamics that sacrifice safety and dynamic feasibility in order to plan efficiently. Conversely, safe trajectories can be computed using more sophisticated dynamic models, but this is typically too slow to be used for real-time planning. We propose a new algorithm FaSTrack: Fast and Safe Tracking for High Dimensional systems. A path or trajectory planner using simplified dynamics to plan quickly can be incorporated into the FaSTrack framework, which provides a safety controller for the vehicle along with a guaranteed tracking error bound. This bound captures all possible deviations due to high dimensional dynamics and external disturbances. Note that FaSTrack is modular and can be used with most current path or trajectory planners. We demonstrate this framework using a 10D nonlinear quadrotor model tracking a 3D path obtained from an RRT planner.
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fastrack a modular framework for fast and guaranteed safe motion planning
Conference on Decision and Control, 2017Co-Authors: Sylvia L. Herbert, Somil Bansal, Jaime F. Fisac, Mo Chen, Claire J TomlinAbstract:Fast and safe navigation of dynamical systems through a priori unknown cluttered environments is vital to many applications of autonomous systems. However, trajectory planning for autonomous systems is computationally intensive, often requiring simplified dynamics that sacrifice safety and dynamic feasibility in order to plan efficiently. Conversely, safe trajectories can be computed using more sophisticated dynamic models, but this is typically too slow to be used for real-time planning. We present the new algorithm FaSTrack: Fast and Safe Tracking. A path or trajectory planner using simplified dynamics to plan quickly can be incorporated into the FaSTrack framework, which provides a safety controller for the vehicle along with a guaranteed tracking error bound. This bound captures all possible deviations due to high dimensional dynamics and external disturbances. FaSTrack is modular and can be used with most current path or trajectory planners. We demonstrate this framework using a 10D nonlinear quadrotor model tracking a 3D path obtained from an RRT planner.
Hideyuki Kawashima - One of the best experts on this subject based on the ideXlab platform.
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safety and feasibility evaluation of planning and execution of surgical revascularisation solely based on coronary cta and ffrct in patients with complex coronary artery disease study protocol of the Fasttrack cabg study
BMJ Open, 2020Co-Authors: Hideyuki Kawashima, Giulio Pompilio, Daniele Andreini, Antonio L Bartorelli, Saima Mushtaq, Enrico Ferrari, Francesco Maisano, Ronny R Buechel, Kaoru TanakaAbstract:Introduction The previously published SYNTAX III REVOLUTION trial demonstrated that clinical decision-making between coronary artery bypass graft (CABG) and percutaneous coronary intervention based on coronary CT angiography (CCTA) had a very high agreement with the treatment decision derived from invasive coronary angiography (ICA). The study objective of the Fasttrack CABG is to assess the feasibility of CCTA and fractional flow reserve derived from CTA (FFRCT) to replace ICA as a surgical guidance method for planning and execution of CABG in patients with three-vessel disease with or without left main disease. Methods and analysis The Fasttrack CABG is an investigator-initiated single-arm, multicentre, prospective, proof-of-concept and first-in-man study with feasibility and safety analysis. Surgical revascularisation strategy and treatment planning will be solely based on CCTA and FFRCT without knowledge of the anatomy defined by ICA. Clinical follow-up visit including CCTA will be performed 30 days after CABG in order to assess graft patency and adequacy of the revascularisation with respect to the surgical planning based on non-invasive imaging (CCTA) with functional assessment (FFRCT) and compared with ICA. Primary feasibility endpoint is CABG planning and execution solely based on CCTA and FFRCT in 114 patients. Primary safety endpoint based on 30 day CCTA is graft assessment and topographical adequacy of the revascularisation procedure. Automatic non-invasive assessment of functional coronary anatomy complexity is also evaluated with FFRCT for functional Synergy Between percutaneous coronary intervention With Taxus and Cardiac Surgery Score assessment on CCTA. CCTA with FFRCT might provide better anatomical and functional analysis of the coronary circulation leading to appropriate anatomical and functional revascularisation, and thereby contributing to a better outcome. Ethics and dissemination Each patient has to provide written informed consent as approved by the ethical committee of the respective clinical site. Results will be submitted for publication in peer-reviewed journals and will be disseminated at scientific conferences. Trial registration number NCT04142021.
Kaoru Tanaka - One of the best experts on this subject based on the ideXlab platform.
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safety and feasibility evaluation of planning and execution of surgical revascularisation solely based on coronary cta and ffrct in patients with complex coronary artery disease study protocol of the Fasttrack cabg study
BMJ Open, 2020Co-Authors: Hideyuki Kawashima, Giulio Pompilio, Daniele Andreini, Antonio L Bartorelli, Saima Mushtaq, Enrico Ferrari, Francesco Maisano, Ronny R Buechel, Kaoru TanakaAbstract:Introduction The previously published SYNTAX III REVOLUTION trial demonstrated that clinical decision-making between coronary artery bypass graft (CABG) and percutaneous coronary intervention based on coronary CT angiography (CCTA) had a very high agreement with the treatment decision derived from invasive coronary angiography (ICA). The study objective of the Fasttrack CABG is to assess the feasibility of CCTA and fractional flow reserve derived from CTA (FFRCT) to replace ICA as a surgical guidance method for planning and execution of CABG in patients with three-vessel disease with or without left main disease. Methods and analysis The Fasttrack CABG is an investigator-initiated single-arm, multicentre, prospective, proof-of-concept and first-in-man study with feasibility and safety analysis. Surgical revascularisation strategy and treatment planning will be solely based on CCTA and FFRCT without knowledge of the anatomy defined by ICA. Clinical follow-up visit including CCTA will be performed 30 days after CABG in order to assess graft patency and adequacy of the revascularisation with respect to the surgical planning based on non-invasive imaging (CCTA) with functional assessment (FFRCT) and compared with ICA. Primary feasibility endpoint is CABG planning and execution solely based on CCTA and FFRCT in 114 patients. Primary safety endpoint based on 30 day CCTA is graft assessment and topographical adequacy of the revascularisation procedure. Automatic non-invasive assessment of functional coronary anatomy complexity is also evaluated with FFRCT for functional Synergy Between percutaneous coronary intervention With Taxus and Cardiac Surgery Score assessment on CCTA. CCTA with FFRCT might provide better anatomical and functional analysis of the coronary circulation leading to appropriate anatomical and functional revascularisation, and thereby contributing to a better outcome. Ethics and dissemination Each patient has to provide written informed consent as approved by the ethical committee of the respective clinical site. Results will be submitted for publication in peer-reviewed journals and will be disseminated at scientific conferences. Trial registration number NCT04142021.
Jian Liang - One of the best experts on this subject based on the ideXlab platform.
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The Index Poisoning Attack in P2P File Sharing Systems
IEEE, 2006Co-Authors: Jian LiangAbstract:Abstract — P2P file-sharing systems have indexes, which users search to find locations of desired titles. In the index poisoning attack, the attacker inserts massive numbers of bogus records into the index for a set of targeted titles. As a result, when a user searches for a targeted title, the index returns bogus results, such as bogus file identifiers, bogus IP addresses, or bogus port numbers. In this paper we first show that both structured and unstructured P2P file-sharing systems are highly vulnerable to the index poisoning attack. We then develop a novel and efficient methodology for estimating index poisoning levels and pollution levels in file-sharing systems. The methodology is efficient in that involves neither the downloading nor the analysis of binary content files. We deploy data-harvesting platforms for Fasttrack, an unstructured file-sharing system, and Overnet, a DHT-based file-sharing system. Applying our methodology to harvested data, we find that index poisoning is pervasive in both systems. We also outline a distributed blacklisting procedure for countering the index poisoning and pollution attacks. I
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Pollution in p2p file sharing systems
2005Co-Authors: Jian Liang, Rakesh Kumar, Keith W. RossAbstract:Abstract-One way tu combat f z P file sharing of copyrighted content is to deposit into the file sharing systems large volumes of polluted files. Without taking sides in the file sharing debate, in this paper we undertake a measurement study af the nature and magnitude of pollution in the Fasttrack P2P network, currently the most popular PZP file sharing system. We develop a crawling platform which crawls the majority of the Fasttrack Network’s 20,000+ supernodes in less than 60 minutes, From the raw data gathered by the crawler for popular audio content, we obtain statistics on the number of unique versions and copies available in a 24-hour period. We develop an automated procedure tu detect whether a given version is polluted or not, and we show that the probabilities of false positives and negatives of the detection procedure are very small. We use the data from the crawler and our pollution detection algorithm to determine the fraction of versions and fraction of copies that are polluted for several recent and old songs. We observe that pollution is pervasive for recent popular songs. We also identify and describe a number of anti-pollution mechanisms. Keywords- Network Measurements. I
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Efficient blacklisting and pollution-level estimation in P2P file-sharing systems
2005Co-Authors: Jian Liang, Naoum Naoumov, Keith W. RossAbstract:Abstract. P2P file-sharing systems are susceptible to pollution attacks, whereby corrupted copies of content are aggressively introduced into the system. Recent research indicates that pollution is extensive in several file sharing systems. In this paper we propose an efficient measurement methodology for identifying the sources of pollution and estimating the levels of polluted content. The methodology can be used to efficiently blacklist polluters, evaluate the success of a pollution campaign, to reduce wasted bandwidth due to the transmission of polluted content, and to remove the noise from content measurement data. The proposed methodology is efficient in that it does not involve the downloading and analysis of binary content, which would be expensive in bandwidth and in computation/human resources. The methodology is based on harvesting metadata from the file sharing system and then processing off-line the harvested meta-data. We apply the technique to the Fasttrack/Kazaa file-sharing network. Analyzing the false positives and false negatives, we conclude that the methodology is efficient and accurate.
Sylvia L. Herbert - One of the best experts on this subject based on the ideXlab platform.
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Planning, Fast and Slow: A Framework for Adaptive Real-Time Safe Trajectory Planning
Proceedings - IEEE International Conference on Robotics and Automation, 2018Co-Authors: David Fridovich-keil, Sylvia L. Herbert, Sampada Deglurkar, Jaime F. Fisac, Claire J TomlinAbstract:Motion planning is an extremely well-studied problem in the robotics community, yet existing work largely falls into one of two categories: computationally efficient but with few if any safety guarantees, or able to give stronger guarantees but at high computational cost. This work builds on a recent development called FaSTrack in which a slow offline computation provides a modular safety guarantee for a faster online planner. We introduce the notion of "meta-planning" in which a refined offline computation enables safe switching between different online planners. This provides autonomous systems with the ability to adapt motion plans to a priori unknown environments in real-time as sensor measurements detect new obstacles, and the flexibility to maneuver differently in the presence of obstacles than they would in free space, all while maintaining a strict safety guarantee. We demonstrate the meta-planning algorithm both in simulation and in hardware using a small Crazyflie 2.0 quadrotor.
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FaSTrack: A modular framework for fast and guaranteed safe motion planning
2017 IEEE 56th Annual Conference on Decision and Control CDC 2017, 2018Co-Authors: Sylvia L. Herbert, Soojean Han, Somil Bansal, Jaime F. Fisac, Mo Chen, Claire J TomlinAbstract:Fast and safe navigation of dynamical systems through a priori unknown cluttered environments is vital to many applications of autonomous systems. However, trajectory planning for autonomous systems is computationally intensive, often requiring simplified dynamics that sacrifice safety and dynamic feasibility in order to plan efficiently. Conversely, safe trajectories can be computed using more sophisticated dynamic models, but this is typically too slow to be used for real-time planning. We propose a new algorithm FaSTrack: Fast and Safe Tracking for High Dimensional systems. A path or trajectory planner using simplified dynamics to plan quickly can be incorporated into the FaSTrack framework, which provides a safety controller for the vehicle along with a guaranteed tracking error bound. This bound captures all possible deviations due to high dimensional dynamics and external disturbances. Note that FaSTrack is modular and can be used with most current path or trajectory planners. We demonstrate this framework using a 10D nonlinear quadrotor model tracking a 3D path obtained from an RRT planner.
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fastrack a modular framework for fast and guaranteed safe motion planning
Conference on Decision and Control, 2017Co-Authors: Sylvia L. Herbert, Somil Bansal, Jaime F. Fisac, Mo Chen, Claire J TomlinAbstract:Fast and safe navigation of dynamical systems through a priori unknown cluttered environments is vital to many applications of autonomous systems. However, trajectory planning for autonomous systems is computationally intensive, often requiring simplified dynamics that sacrifice safety and dynamic feasibility in order to plan efficiently. Conversely, safe trajectories can be computed using more sophisticated dynamic models, but this is typically too slow to be used for real-time planning. We present the new algorithm FaSTrack: Fast and Safe Tracking. A path or trajectory planner using simplified dynamics to plan quickly can be incorporated into the FaSTrack framework, which provides a safety controller for the vehicle along with a guaranteed tracking error bound. This bound captures all possible deviations due to high dimensional dynamics and external disturbances. FaSTrack is modular and can be used with most current path or trajectory planners. We demonstrate this framework using a 10D nonlinear quadrotor model tracking a 3D path obtained from an RRT planner.