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Book ; Online: Large deviation properties for pattern statistics in primitive rational models

Goldwurm, Massimiliano / Vignati, Marco

2023

Abstract: We present a large deviation property for the pattern statistics representing the number of occurrences of a symbol in words of given length generated at random according to a rational stochastic model. The result is obtained assuming that in the model ... ...

Abstract	We present a large deviation property for the pattern statistics representing the number of occurrences of a symbol in words of given length generated at random according to a rational stochastic model. The result is obtained assuming that in the model the overall weighted transition matrix is primitive. In particular we obtain a rate function depending on the main eigenvalue and eigenvectors of that matrix. Under rather mild conditions, we show that the range of validity of our large deviation estimate can be extended to the interval (0,1), which represents in our context the largest possible open interval of validity of the property.
Keywords	Mathematics - Probability ; Computer Science - Formal Languages and Automata Theory
Publishing date	2023-06-13
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Infrastructure-Based Vehicle Localization through Camera Calibration for I2V Communication Warning.

Vignarca, Daniele / Vignati, Michele / Arrigoni, Stefano / Sabbioni, Edoardo

Sensors (Basel, Switzerland)

2023 Volume 23, Issue 16

Abstract: In recent years, the research on object detection and tracking is becoming important for the development of advanced driving assistance systems (ADASs) and connected autonomous vehicles (CAVs) aiming to improve safety for all road users involved. ... ...

Abstract	In recent years, the research on object detection and tracking is becoming important for the development of advanced driving assistance systems (ADASs) and connected autonomous vehicles (CAVs) aiming to improve safety for all road users involved. Intersections, especially in urban scenarios, represent the portion of the road where the most relevant accidents take place; therefore, this work proposes an I2V warning system able to detect and track vehicles occupying the intersection and representing an obstacle for other incoming vehicles. This work presents a localization algorithm based on image detection and tracking by a single camera installed on a roadside unit (RSU). The vehicle position in the global reference frame is obtained thanks to a sequence of linear transformations utilizing intrinsic camera parameters, camera height, and pitch angle to obtain the vehicle's distance from the camera and, thus, its global latitude and longitude. The study brings an experimental analysis of both the localization accuracy, with an average error of 0.62 m, and detection reliability in terms of false positive (1.9%) and missed detection (3.6%) rates.
Language	English
Publishing date	2023-08-12
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2052857-7
ISSN	1424-8220 ; 1424-8220
ISSN (online)	1424-8220
ISSN	1424-8220
DOI	10.3390/s23167136
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Vehicle Teleoperation: Human in the Loop Performance Comparison of Smith Predictor with Novel Successive Reference-Pose Tracking Approach.

Prakash, Jai / Vignati, Michele / Sabbioni, Edoardo / Cheli, Federico

Sensors (Basel, Switzerland)

2022 Volume 22, Issue 23

Abstract: Vehicle teleoperation has the ability to bridge the gap between completely automated driving and manual driving by remotely monitoring and operating autonomous vehicles when their automation fails. Among many challenges related to vehicle teleoperation, ... ...

Abstract	Vehicle teleoperation has the ability to bridge the gap between completely automated driving and manual driving by remotely monitoring and operating autonomous vehicles when their automation fails. Among many challenges related to vehicle teleoperation, the considered ones in this work are variable time delay, saturation of actuators installed in vehicle, and environmental disturbance, which together limit the teleoperation performance. State-of-the-art predictive techniques estimate vehicle states to compensate for the delays, but the predictive states do not account for sudden disturbances that the vehicle observes, which makes the human-picked steer inadequate. This inadequacy of steer deteriorates the path-tracking performance of vehicle teleoperation. In the proposed successive reference-pose-tracking (SRPT) approach, instead of transmitting steering commands, the reference trajectory, in the form of successive reference poses, is transmitted to the vehicle. This paper introduces a method of generation of successive reference poses with a joystick steering wheel and compares the human-in-loop path-tracking performance of the Smith predictor and SRPT approach. Human-in-loop experiments (with 18 different drivers) are conducted using a simulation environment that consists of the integration of a real-time 14-DOF Simulink vehicle model and Unity game engine in the presence of bidirectional variable delays. Scenarios for performance comparison are low adhesion ground, strong lateral wind, tight corners, and sudden obstacle avoidance. Result shows significant improvement in reference tracking and in reducing human effort in all scenarios using the SRPT approach.
Language	English
Publishing date	2022-11-24
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2052857-7
ISSN	1424-8220 ; 1424-8220
ISSN (online)	1424-8220
ISSN	1424-8220
DOI	10.3390/s22239119
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Book ; Online: Vehicle Teleoperation

Prakash, Jai / Vignati, Michele / Sabbioni, Edoardo

Performance Assessment of SRPT Approach Under State Estimation Errors

2023

Abstract: Vehicle teleoperation has numerous potential applications, including serving as a backup solution for autonomous vehicles, facilitating remote delivery services, and enabling hazardous remote operations. However, complex urban scenarios, limited ... ...

Abstract	Vehicle teleoperation has numerous potential applications, including serving as a backup solution for autonomous vehicles, facilitating remote delivery services, and enabling hazardous remote operations. However, complex urban scenarios, limited situational awareness, and network delay increase the cognitive workload of human operators and degrade teleoperation performance. To address this, the successive reference pose tracking (SRPT) approach was introduced in earlier work, which transmits successive reference poses to the remote vehicle instead of steering commands. The operator generates reference poses online with the help of a joystick steering and an augmented display, potentially mitigating the detrimental effects of delays. However, it is not clear which minimal set of sensors is essential for the SRPT vehicle teleoperation control loop. This paper tests the robustness of the SRPT approach in the presence of state estimation inaccuracies, environmental disturbances, and measurement noises. The simulation environment, implemented in Simulink, features a 14-dof vehicle model and incorporates difficult maneuvers such as tight corners, double-lane changes, and slalom. Environmental disturbances include low adhesion track regions and strong cross-wind gusts. The results demonstrate that the SRPT approach, using either estimated or actual states, performs similarly under various worst-case scenarios, even without a position sensor requirement. Additionally, the designed state estimator ensures sufficient performance with just an inertial measurement unit, wheel speed encoder, and steer encoder, constituting a minimal set of essential sensors for the SRPT vehicle teleoperation control loop. Comment: This work has been submitted to Elsevier for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible
Keywords	Computer Science - Robotics
Subject code	629
Publishing date	2023-05-19
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: SRPT vs Smith Predictor for Vehicle Teleoperation

Prakash, Jai / Vignati, Michele / Sabbioni, Edoardo

2023

Abstract: Vehicle teleoperation has potential applications in fallback solutions for autonomous vehicles, remote delivery services, and hazardous operations. However, network delays and limited situational awareness can compromise teleoperation performance and ... ...

Abstract	Vehicle teleoperation has potential applications in fallback solutions for autonomous vehicles, remote delivery services, and hazardous operations. However, network delays and limited situational awareness can compromise teleoperation performance and increase the cognitive workload of human operators. To address these issues, we previously introduced the novel successive reference pose tracking (SRPT) approach, which transmits successive reference poses to the vehicle instead of steering commands. This paper compares the stability and performance of SRPT with Smith predictor-based approaches for direct vehicle teleoperation in challenging scenarios. The Smith predictor approach is further categorized, one with Lookahead driver and second with Stanley driver. Simulations are conducted in a Simulink environment, considering variable network delays and different vehicle speeds, and include maneuvers such as tight corners, slalom, low-adhesion roads, and strong crosswinds. The results show that the SRPT approach significantly improves stability and reference tracking performance, with negligible effect of network delays on path tracking. Our findings demonstrate the effectiveness of SRPT in eliminating the detrimental effect of network delays in vehicle teleoperation. Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible
Keywords	Computer Science - Robotics ; Electrical Engineering and Systems Science - Systems and Control
Subject code	629
Publishing date	2023-04-27
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Vehicle Teleoperation

Prakash, Jai / Vignati, Michele / Sabbioni, Edoardo / Cheli, Federico

Successive Reference-Pose Tracking

2022

Abstract: Vehicle teleoperation is an interesting feature in many fields. A typical problem of teleoperation is communication time delay which, together with actuator saturation and environmental disturbance, can cause a vehicle deviation from the target ... ...

Abstract	Vehicle teleoperation is an interesting feature in many fields. A typical problem of teleoperation is communication time delay which, together with actuator saturation and environmental disturbance, can cause a vehicle deviation from the target trajectory imposed by the human operator who imposes to the vehicle a steering wheel angle reference and a speed/acceleration reference. With predictive techniques, time-delay can be accounted at sufficient extent. But, in presence of disturbances, due to the absence of instantaneous haptic and visual feedback, human-operator steering command transmitted to the the vehicle is unaccounted with disturbances observed by the vehicle. To improve reference tracking without losing promptness in driving control, reference trajectory in the form of successive reference poses can be transmitted instead of steering commands to the vehicle. We introduce this new concept, namely, the 'successive reference-pose tracking (SRPT)' to improve path tracking in vehicle teleoperation. This paper discusses feasibility and advantages of this new method, compare to the smith predictor control approach. Simulations are performed in SIMULINK environment, where a 14-dof vehicle model is being controlled with Smith and SRPT controllers in presence of variable network delay. Scenarios for performance comparison are low adhesion ground, strong lateral wind and steer-rate demanding maneuvers. Simulation result shows significant improvement in reference tracking with SRPT approach. Comment: VPPC2022 conference submitted
Keywords	Computer Science - Robotics
Subject code	629
Publishing date	2022-06-08
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Predictive Display with Perspective Projection of Surroundings in Vehicle Teleoperation to Account Time-delays

Prakash, Jai / Vignati, Michele / Vignarca, Daniele / Sabbioni, Edoardo / Cheli, Federico

2022

Abstract: Teleoperation provides human operator sophisticated perceptual and cognitive skills into an over the network control loop. It gives hope of addressing some challenges related to vehicular autonomy which is based on artificial intelligence by providing a ... ...

Abstract	Teleoperation provides human operator sophisticated perceptual and cognitive skills into an over the network control loop. It gives hope of addressing some challenges related to vehicular autonomy which is based on artificial intelligence by providing a backup plan. Variable network time delays in data transmission is the major problem in teleoperating a vehicle. On 4G network, variability of these delays is high. Due to this, both video streaming and driving commands encounter variable time delay. This paper presents an approach of providing the human operator a forecast video stream which replicates future perspective of vehicle field of view accounting the delay present in the network. Regarding the image transformation, perspective projection technique is combined with correction given by smith predictor in the control loop. This image transformation accounts current time delay and tries to address both issues, time delays as well as its variability. For experiment sake, only frontward field of view is forecast. Performance is evaluated by performing online vehicle teleoperation on street edge case maneuvers and later comparing the path deviation with and without perspective projection.
Keywords	Computer Science - Human-Computer Interaction ; Computer Science - Robotics
Subject code	629
Publishing date	2022-11-21
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online ; Thesis: Model of the Response Function of CUORE Bolometers

Vignati, Marco

(Springer Theses ; 38)

2011

Abstract: The neutrino is probably the most elusive elementary particle discovered so far. Its mass is very small and still unknown, and it is considered a key quantity in many theories beyond the Standard Model of particle physics. The smallness of the mass could ...

Author's details	by Marco Vignati
Series title	Springer Theses ; 38
Abstract	The neutrino is probably the most elusive elementary particle discovered so far. Its mass is very small and still unknown, and it is considered a key quantity in many theories beyond the Standard Model of particle physics. The smallness of the mass could be explained if neutrinos are, unlike all other particles, equal to their own antiparticles, thus following the conjecture of E. Majorana. The double beta decay without emission of neutrinos is a nuclear process that can happen only if the neutrino is a Majorana particle. Observation of this decay would therefore necessarily imply that neutrinos are Majorana particles and would set the mass scale, a breakthrough in our understanding of nature. The CUORE experiment will search for the neutrinoless double beta decay in 130Te, using 1 ton of TeO2 bolometric detectors. Bolometers are calorimeters that operate at cryogenic temperatures, able to measure the temperature rise produced by the energy release of an impinging particle. They feature good resolution and low background, making them excellent detectors to search for rare decays. The performances of the experiment are currently limited by temperature instabilities of the bolometers and by a poor understanding of their data. Measuring the energy deposited by a particle, in fact, is complicated and the shape of the signal depends on the energy. In this thesis a model of the signal of TeO2 bolometers is developed. It is able to explain the origin of the unwanted features that would limit the performances of CUORE. The application of the model to data from test bolometers led to great improvements of the results in terms of energy resolution, energy calibration, and signal shape discrimination. This thesis has been awarded at the Department of Physics, Universita di Roma - La Sapienza, Italy. With a Foreword by Professor Fernando Ferroni.
Keywords	Particle acceleration ; Physics ; Quantum theory
Language	English
Size	Online-Ressource, v.: digital
Publisher	Springer Science+Business Media B.V
Publishing place	Dordrecht
Document type	Book ; Online ; Thesis
Thesis / German Habilitation thesis	Zugl.: Diss
Note	Includes bibliographical references
ISBN	9789400712317 ; 9789400712324 ; 9400712316 ; 9400712324
DOI	10.1007/978-94-007-1232-4
Database	Former special subject collection: coastal and deep sea fishing

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Book ; Online ; Thesis: Model of the Response Function of CUORE Bolometers

Vignati, Marco

(Springer Theses ; 38)

2011

Author's details	by Marco Vignati
Series title	Springer Theses ; 38
Abstract	The neutrino is probably the most elusive elementary particle discovered so far. Its mass is very small and still unknown, and it is considered a key quantity in many theories beyond the Standard Model of particle physics. The smallness of the mass could be explained if neutrinos are, unlike all other particles, equal to their own antiparticles, thus following the conjecture of E. Majorana. The double beta decay without emission of neutrinos is a nuclear process that can happen only if the neutrino is a Majorana particle. Observation of this decay would therefore necessarily imply that neutrinos are Majorana particles and would set the mass scale, a breakthrough in our understanding of nature. The CUORE experiment will search for the neutrinoless double beta decay in 130Te, using 1 ton of TeO2 bolometric detectors. Bolometers are calorimeters that operate at cryogenic temperatures, able to measure the temperature rise produced by the energy release of an impinging particle. They feature good resolution and low background, making them excellent detectors to search for rare decays. The performances of the experiment are currently limited by temperature instabilities of the bolometers and by a poor understanding of their data. Measuring the energy deposited by a particle, in fact, is complicated and the shape of the signal depends on the energy. In this thesis a model of the signal of TeO2 bolometers is developed. It is able to explain the origin of the unwanted features that would limit the performances of CUORE. The application of the model to data from test bolometers led to great improvements of the results in terms of energy resolution, energy calibration, and signal shape discrimination. This thesis has been awarded at the Department of Physics, Universita di Roma - La Sapienza, Italy. With a Foreword by Professor Fernando Ferroni.
Keywords	Particle acceleration ; Physics ; Quantum theory
Language	English
Size	Online-Ressource, v.: digital
Publisher	Springer Science+Business Media B.V
Publishing place	Dordrecht
Document type	Book ; Online ; Thesis
Thesis / German Habilitation thesis	Zugl.: Diss
Note	Includes bibliographical references
ISBN	9789400712317 ; 9789400712324 ; 9400712316 ; 9400712324
DOI	10.1007/978-94-007-1232-4
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online ; Thesis: Model of the response function of CUORE bolometers

Vignati, Marco

(Springer theses)

2011

Abstract: Large mass bolometers are used in particle physics experiments to search for rare processes, like neutrinoless double beta decay and dark matter interactions. In the next years the CUORE experiment (a 1 Ton detector composed by 1000 crystals of TeO2 ... ...

Author's details	Marco Vignati
Series title	Springer theses
Abstract	Large mass bolometers are used in particle physics experiments to search for rare processes, like neutrinoless double beta decay and dark matter interactions. In the next years the CUORE experiment (a 1 Ton detector composed by 1000 crystals of TeO2 operated as bolometers in a large cryostat at 10mK) will be the particle physics experiment with the highest chance of discovering the Majorana neutrino, a long standing and yet fundamental question of particle physics. The study presented in this book was performed on the bolometers of the CUORE experiment. The response function of these detectors
Keywords	Bolometer ; Neutrinos
Language	English
Size	Online-Ressource (xii, 107 p)
Publisher	Springer
Publishing place	Dordrecht ;New York
Document type	Book ; Online ; Thesis
Thesis / German Habilitation thesis	Thesis (Ph. D.)--Sapienza Università di Roma
Note	Includes bibliographical references
ISBN	9400712324 ; 9789400712317 ; 9789400712324 ; 9400712316
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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