Letteratura scientifica selezionata sul tema "Proximity-Based Control"
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Articoli di riviste sul tema "Proximity-Based Control"
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Mauer, Georg F. "An end-effector based imaging proximity sensor". Journal of Robotic Systems 6, n. 3 (giugno 1989): 301–16. http://dx.doi.org/10.1002/rob.4620060307.
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Di Mauro, G., M. Schlotterer, S. Theil e M. Lavagna. "Nonlinear Control for Proximity Operations Based on Differential Algebra". Journal of Guidance, Control, and Dynamics 38, n. 11 (novembre 2015): 2173–87. http://dx.doi.org/10.2514/1.g000842.
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Matsunaga, Shigeki, e Masakatsu Shibasaki. "Multimetallic Bifunctional Asymmetric Catalysis Based on Proximity Effect Control". Bulletin of the Chemical Society of Japan 81, n. 1 (15 gennaio 2008): 60–75. http://dx.doi.org/10.1246/bcsj.81.60.
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Garrido-Martinez, Jessenia, e Patricio Medina-Chicaiza. "Electoral Advertising Based on Proximity Marketing". International Business Research 12, n. 9 (26 agosto 2019): 52. http://dx.doi.org/10.5539/ibr.v12n9p52.
Testo completoAbstract (sommario):
This study seeks to propose a strategy for electoral advertising based on proximity marketing. It arises as a response to the problem detected through direct observation and structured interviews with specialists (experts in electoral marketing, politicians, publicists and ICT leaders) which evidenced the lack of technological tools for electoral advertising such as proximity marketing. In addition, theoretical methods and documentary analysis were used. The results include a proposed strategy with the following phases: search for a supplier, planning, multimedia documents, technological conditions, implementation, control.
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Long, Jiateng, e Fen Wu. "Iterative-Learning-Control-Based Tracking for Asteroid Close-Proximity Operations". Journal of Guidance, Control, and Dynamics 42, n. 5 (maggio 2019): 1195–203. http://dx.doi.org/10.2514/1.g003884.
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Tamayo Segarra, Jose Ignacio, Bilal Al Jammal e Hakima Chaouchi. "New IoT proximity service based heterogeneous RFID readers collision control". PSU Research Review 1, n. 2 (14 agosto 2017): 127–49. http://dx.doi.org/10.1108/prr-03-2017-0019.
Testo completoAbstract (sommario):
Purpose Internet of Things’ (IoT’s) first wave started with tracking services for better inventory management mainly using radio frequency identification (RFID) technology. Later on, monitoring services became one of the major interests, including sensing technologies, and then more actuation for remote control-type of IoT applications such as smart homes, smart cities and Industry 4.0. In this paper, the authors focus on the RFID technology impairment. They propose to take advantage of the mature IoT technologies that offer native service discovery such as blutooth or LTE D2D ProSe or Wifi Direct. Using the automatic service discovery in the new framework will make heterogeneous readers aware of the presence of other readers and this will be used by the proposed distributed algorithm to better control the multiple RFID reader interference problem. The author clearly considers emerging Industry 4.0 use case, where RFID technology is of major interest for both identification and tracking. To enhance the RFID tag reading performance, collisions in the RFID frequency should be minimized with reader-to-reader coordination protocols. In this paper, the author proposes a simple distributed reader anti-collision protocol named DiSim that makes use of proximity services of IoT network and is compliant with the current RFID standards. The author evaluates the efficiency of the proposal via simulation. Design/methodology/approach In this paper, the author proposes a simple distributed reader anti-collision protocol named DiSim that makes use of proximity services of IoT network and is compliant with the current RFID standards. The author evaluates the efficiency of the proposal via simulation to study its behavior in very dense and heterogeneous RFID environments. Specifically, the author explores the coexistence of powerful static readers and small mobile readers, comparing the proposal with a standard ETSI CSMA method. The proposal reduces significantly the number of access attempts, which are resource-expensive for the readers. The results show that the objectives of DiSim are met, producing low reader collision probability and, however, having lower average readings per reader per time. Findings DiSim is evaluated with the ETSI standard LBT protocol for multi-reader environments in several environments with varied levels of reader and tag densities, having both static powerful RFID readers and heterogeneous randomly moving mobile RFID readers. It effectively reduces the number of backoffs or contentions for the RFID channel. This has high reading success rate due to the avoided collisions; however, the readers are put to wait, and DiSim has less average readings per reader per time. As an additional side evaluation, the ETSI standard LBT mechanism was found to present a good performance for low-density mid-coverage scenarios, however, with high variability on the evaluation results. Research limitations/implications To show more results, the author needs to do real experimentation in a warehouse, such as Amazon warehouse, where he expects to have more and more robots, start shelves, automatic item finding on the shelve, etc. Practical implications Future work considers experimentation in a real warehouse equipped with heterogeneous RFID readers and real-time analysis of RFID reading efficiency also combined with indoor localization and navigation for warehouse mobile robots. Social implications More automatization is expected in the future; this work makes the use of RFID technology more efficient and opens more possibilities for services deployment in different domains such as the industry which was considered not only in this paper but also in smart cites and smart homes. Originality/value Compared to the literature, the proposal offers the advantage to not be dependent on a centralized server controlling the RFID readers. It also offers the possibility for an existing RFID architecture to add new readers from a different manufacturer, as the readers using the approach will have the possibility to discover the capabilities of the new interaction other RFID readers. This solution takes advantage of the available proximity service that will be more and more offered by the IoT technologies.
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Sun, Liang, e Zewei Zheng. "Disturbance Observer-Based Robust Saturated Control for Spacecraft Proximity Maneuvers". IEEE Transactions on Control Systems Technology 26, n. 2 (marzo 2018): 684–92. http://dx.doi.org/10.1109/tcst.2017.2669145.
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Severson, Frederick E. "Proximity control of on-board processor-based model train sound and control system". Journal of the Acoustical Society of America 126, n. 2 (2009): 930. http://dx.doi.org/10.1121/1.3204334.
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Kurahashi, A., M. Adachi e M. Idesawa. "A prototype of optical proximity sensor based on RORS". Journal of Robotic Systems 3, n. 2 (marzo 1986): 183–90. http://dx.doi.org/10.1002/rob.4620030206.
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Agudo, Isaac, Ruben Rios e Javier Lopez. "A privacy-aware continuous authentication scheme for proximity-based access control". Computers & Security 39 (novembre 2013): 117–26. http://dx.doi.org/10.1016/j.cose.2013.05.004.
Testo completoTesi sul tema "Proximity-Based Control"
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Chan, Teck-Wai. "Proximity-to-separation based energy function control strategy for power system stability". Thesis, Queensland University of Technology, 2003. https://eprints.qut.edu.au/15840/1/Teck-Wai_Chan_Thesis.pdf.
Testo completoAbstract (sommario):
The issue of angle instability has been widely discussed in the power engineering literature. Many control techniques have been proposed to provide the complementary synchronizing and damping torques through generators and/or network connected power apparatus such as FACTs, braking resistors and DC links. The synchronizing torque component keeps all generators in synchronism while damping torque reduces oscillations and returns the power system to its pre-fault operating condition. One of the main factors limiting the transfer capacity of the electrical transmission network is the separation of the power system at weak links which can be understood by analogy with a large spring-mass system. However, this weak-links related problem is not dealt with in existing control designs because it is non-trivial during transient period to determine credible weak links in a large power system which may consist of hundreds of strong and weak links. The difficulty of identifying weak links has limited the performance of existing controls when it comes to the synchronization of generators and damping of oscillations. Such circumstances also restrict the operation of power systems close to its transient stability limits. These considerations have led to the primary research question in this thesis, "To what extent can the synchronization of generators and damping of oscillations be maximized to fully extend the transient stability limits of power systems and to improve the transfer capacity of the network?" With the recent advances in power electronics technology, the extension of transfer capacity is becoming more readily achievable. Complementary to the use of power electronics technology to improve transfer capacity, this research develops an improved control strategy by examining the dynamics of the modes of separation associated with the strong and weak links of the reduced transmission network. The theoretical framework of the control strategy is based on Energy Decomposition and Unstable Equilibrium Points. This thesis recognizes that under extreme loadings of the transmission network containing strong and weak links, weak-links are most likely to dictate the transient stability limits of the power system. We conclude that in order to fully extend the transient stability limits of power system while maximizing the value of control resources, it is crucial for the control strategy to aim its control effort at the energy component that is most likely to cause a separation. The improvement in the synchronization amongst generators remains the most important step in the improvement of the transfer capacity of the power system network.
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Chan, Teck-Wai. "Proximity-to-Separation Based Energy Function Control Strategy for Power System Stability". Queensland University of Technology, 2003. http://eprints.qut.edu.au/15840/.
Testo completoAbstract (sommario):
The issue of angle instability has been widely discussed in the power engineering literature. Many control techniques have been proposed to provide the complementary synchronizing and damping torques through generators and/or network connected power apparatus such as FACTs, braking resistors and DC links. The synchronizing torque component keeps all generators in synchronism while damping torque reduces oscillations and returns the power system to its pre-fault operating condition. One of the main factors limiting the transfer capacity of the electrical transmission network is the separation of the power system at weak links which can be understood by analogy with a large spring-mass system. However, this weak-links related problem is not dealt with in existing control designs because it is non-trivial during transient period to determine credible weak links in a large power system which may consist of hundreds of strong and weak links. The difficulty of identifying weak links has limited the performance of existing controls when it comes to the synchronization of generators and damping of oscillations. Such circumstances also restrict the operation of power systems close to its transient stability limits. These considerations have led to the primary research question in this thesis, "To what extent can the synchronization of generators and damping of oscillations be maximized to fully extend the transient stability limits of power systems and to improve the transfer capacity of the network?" With the recent advances in power electronics technology, the extension of transfer capacity is becoming more readily achievable. Complementary to the use of power electronics technology to improve transfer capacity, this research develops an improved control strategy by examining the dynamics of the modes of separation associated with the strong and weak links of the reduced transmission network. The theoretical framework of the control strategy is based on Energy Decomposition and Unstable Equilibrium Points. This thesis recognizes that under extreme loadings of the transmission network containing strong and weak links, weak-links are most likely to dictate the transient stability limits of the power system. We conclude that in order to fully extend the transient stability limits of power system while maximizing the value of control resources, it is crucial for the control strategy to aim its control effort at the energy component that is most likely to cause a separation. The improvement in the synchronization amongst generators remains the most important step in the improvement of the transfer capacity of the power system network.
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Wenn, Chad, e Chad Wenn. "Lyapunov-Based Control of Coupled Translational-Rotational Close-Proximity Spacecraft Dynamics and Docking". Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/626389.
Testo completoAbstract (sommario):
This work presents a non-linear control strategy for the docking of two spacecraft in a leader-follower orbit pattern. The chief craft is assumed to be in a circular orbit around a celestial body. The deputy craft is assumed to have a separation distance from the chief that is small compared to the orbital radius of the chief. Furthermore, the relative dynamics of these crafts can be described by the Hill-Clohessy-Wiltshire equations. The control strategy developed is able to regulate the relative translational distance and velocity of the docking feature points on the two craft with globally asymptotic stability. Furthermore, the control strategy is able to regulate the relative rotational velocity and relative attitude, between the two craft, to that which it is required for successful docking. The rotational control is achieved with “almost” globally asymptotic stability, inclusive of an infinitesimally small unstable manifold. Other researchers in this field have shown that this unstable manifold is easily avoided using advanced control methods. These control laws are developed using Lyapunov’s Direct Method, and have asymptotic stability claims per the use of the Mukherjee-Chen theorem. Numerical Monte-Carlo simulation shows asymptotic stability for a subset of the domain of convergence for the developed control laws. Un-modeled torques and accelerations are later imposed on the system. The control laws are then augmented with integral feedback terms, and the closed loop system, with the augmented control laws, retains the asymptotic stability claims.
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Salgueiro, Filipe Nuno Ricardo. "Nonlinear pose control and estimation for space proximity operations: an approach based on dual quaternions". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53055.
Testo completoAbstract (sommario):
The term proximity operations has been widely used in recent years to describe a wide range of space missions that require a spacecraft to remain close to another space object. Such missions include, for example, the inspection, health monitoring, surveillance, servicing, and refueling of a space asset by another spacecraft. One of the biggest challenges in autonomous space proximity operations, either cooperative or uncooperative, is the need to autonomously and accurately track time-varying relative position and attitude references, i.e., pose references, with respect to a moving target, in order to avoid on-orbit collisions and achieve the overall mission goals. In addition, if the target spacecraft is uncooperative, the Guidance, Navigation, and Control (GNC) system of the chaser spacecraft must not rely on any help from the target spacecraft. In this case, vision-based sensors, such as cameras, are typically used to measure the relative pose between the spacecraft. Although vision-based sensors have several attractive properties, they introduce new challenges, such as no direct linear and angular velocity measurements, slow update rates, and high measurement noise.
This dissertation investigates the problem of autonomously controlling and estimating the pose of a chaser spacecraft with respect to a moving target spacecraft, possibly uncooperative. Since this problem is inherently hard, the standard approach in the literature is to split the attitude-tracking problem from the position-tracking problem. Whereas the attitude-tracking problem is relatively simple, since the rotational motion is independent from the translational motion, the position-tracking problem is more complicated, as the translational motion depends on the rotational motion. Hence, whereas strong theoretical results exist for the attitude problem, the position problem typically requires additional assumptions. An alternative, more general approach to the pose control and estimation problems is to consider the fully coupled 6-DOF motion. However, fewer results exist that directly address this higher dimensional problem.
The main contribution of this dissertation is to show that dual quaternions can be used to extend the theoretical results that exist for the attitude motion into analogous results for the combined position and attitude motion. Moreover, this dissertation shows that this can be accomplished by (almost) just replacing quaternions by dual quaternions in the original derivations. This is because dual quaternions are built on and are an extension of classical quaternions. Dual quaternions provide a compact representation of the pose of a frame with respect to another frame.
Using this approach, three new results are presented in this dissertation. First, a pose-tracking controller that does not require relative linear and angular velocity measurements is derived with vision-based sensors in mind. Compared to existing literature, the proposed velocity-free pose-tracking controller guarantees that the pose of the chaser spacecraft will converge to the desired pose independently of the initial state, even if the reference motion is not sufficiently exciting. In addition, the convergence region does not depend on the gains of the controller.
Second, a Dual Quaternion Multiplicative Extended Kalman Filter (DQ-MEKF) is developed from the highly successful Quaternion MEKF (Q-MEKF) as an alternative way to achieve pose-tracking without velocity measurements. Existing dual quaternion EKFs are additive, not multiplicative, and have two additional states. The DQ-MEKF is experimentally validated and compared with two conventional EKFs on the 5-DOF platform of the Autonomous Spacecraft Testing of Robotic Operations in Space (ASTROS) facility at the School of Aerospace Engineering at Georgia Tech. Finally, the velocity-free pose-tracking controller is compared qualitatively and quantitatively to a pose-tracking controller that uses the velocity estimates produced by the DQ-MEKF through a realistic proximity operations simulation.
Third, a pose-tracking controller that does not require the mass and inertia matrix of the chaser satellite is suggested. This inertia-free controller takes into account the gravitational acceleration, the gravity-gradient torque, the perturbing acceleration due to Earth's oblateness, and constant -- but otherwise unknown -- disturbance forces and torques. Sufficient conditions on the reference pose are also given that guarantee the identification of the mass and inertia matrix of the satellite. Compared to the existing literature, this controller has only as many states as unknown elements and it does not require a priori known upper bounds on any states or parameters.
Finally, the inertia-free pose-tracking controller and the DQ-MEKF are tested on a high-fidelity simulation of the 5-DOF platform of the ASTROS facility and also experimentally validated on the actual platform. The equations of motion of the 5-DOF platform, on which the high-fidelity simulation is based, are derived for three distinct cases: a 3-DOF case, a 5-DOF case, and a (2+1)-DOF case. Four real-time experiments were run on the platform. In the first, a sinusoidal reference attitude with respect to the inertial frame is tracked using VSCMGs. In the second, a constant reference attitude is maintained with respect to a target object using VSCMGs and measurements from a camera. In the third, the same sinusoidal reference attitude with respect to the inertial frame tracked in the first experiment is now tracked using cold-gas thrusters. Finally, in the fourth and last experiment, a time-varying 5-DOF reference pose with respect to the inertial frame is tracked using cold-gas thrusters.
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Li, Ni. "Vision based trajectory tracking of space debris in close proximity via integrated estimation and control". Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4966.
Testo completoAbstract (sommario):
Since the launch of the first rocket by the scientists during the World War II , mankind continues their exploration of space. Those space explorations bring the benefits to human, such as high technology products like GPS, cell phone, etc. and in-depth insight of outside of the earth. However, they produce millions of debris with a total estimated mass of more than 3,000,000 kg in the space around the earth, which has and will continue to threat the safety of manned or unmanned space exploration. According to the research, at least tens of spacecraft were considered been damaged or destroyed by the debris left in the space. Thus, the increasingly cluttered environment in space is placing a premium on techniques capable of tracking and estimating the trajectory of space debris. Among debris, the pieces smaller than 1cm are unable to damage spacecraft because of the crafts' shields, while the pieces larger than 10cm can be tracked by ground-based radars or a radar network. However, unlike the debris within these size ranges, the debris larger than 1 cm and smaller than 10 cm are able to hurt the shield of space craft and are hard to be detected by the exiting technical equipments because of their small size and cross-section area. Accordingly it is always a challenge for spacecraft or satellite mission designers to consider explicitly the ones ranged from 1 cm to 10 cm a priori.; To tackle this challenge, a vision based debris' trajectory tracking method is presented in the thesis. Unlike radar tracking, vision based tracking doesn't require knowledge of a debris' cross-section, regardless of its size. In this work, two cameras onboard of satellites in a formation are used to track the debris in close proximity. Also to differentiate the target debris from other clutters (i.e. the debris that are not tracked intentionally), a data association technique is investigated. A two-stage nonlinear robust controller is developed to adjust the attitude of the satellites such that the target debris is always inside of the field of view of the cameras. Capabilities of the proposed integrated estimation and control methods are validated in the simulations.ID: 029809810; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references (p. 41-48).
M.S.
Masters
Mechanical, Materials, and Aerospace Engineering
Engineering and Computer Science
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Thomas, John. "Assembly task in congested space using sensor-based control". Electronic Thesis or Diss., Université de Rennes (2023-....), 2024. https://ged.univ-rennes1.fr/nuxeo/site/esupversions/97ef6af4-7235-478c-857a-663748e91f68.
Testo completoAbstract (sommario):
Dans cette thèse, un système multi-sensoriel composé de capteurs proximétriques, appelé réseau proximétriques, est proposé. En l’attachant à l’effecteur, il permet à un robot d’effectuer des tâches de positionnement plan sur plan et de positionnement par rapport à un cylindre. L’analyse de la stabilité de la tâche de positionnement plan sur plan est effectuée en obtenant la forme explicite pour la pseudo-inverse de la matrice d’interaction. Les informations de proximité et de vision sont ensuite combinées pour traiter le positionnement dans un espace encombré pour une tâche d’assemblage à l’aide de capteurs sans contact dans le cadre de la commande référencée multi-capteurs. Le réseau proximétrique est enroulé autour du bras du manipulateur pour permettre d’éviter les collisions alors que l’asservissement visuel à partir de 4 points assure le positionnement. Divers résultats expérimentaux et de simulation sont fournis pour valider la théorie. Des formes explicites de la base duale sont obtenues pour des tâches incluant le suivi plan sur plan et le positionnement par rapport à un cylindre avec un minimum de capteurs et un asservissement visuel à partir de 3 points. La base duale est associée à l’espace linéaire des torseurs d’interaction qui forment les composantes de la matrice d’interaction. Cela conduit à des équations explicites capteursIn this thesis, a multi-sensory system consisting of proximity sensors termed proximity array is proposed. While attaching it to the end-effector it enables a robot to perform plane-to-plane positioning task and positioning wrt. a cylinder. Stability analysis of plane-to-plane positioning task is considered by obtaining an explicit form for the pseudo-inverse of the interaction matrix. Proximity and vision information are then combined to address positioning in congested space for assembly task using non-contact sensors. The proximity arrays are wrapped around the arm of the manipulator to enable collision avoidance and 4-point Visual Servoing ensures positioning. Various experimental and simulation results are provided to validate the theory. Explicit forms of dual basis are obtained for tasks including plane-to-plane following and positioning wrt. a cylinder with minimal sensors long with 3-point Visual Servoing. Dual basis is associated to the linear space of interaction screws that form the components of interaction matrix. This leads to closed-form equations in Sensor-based Control
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Giftsun, Nirmal. "Handling uncertainty and variability in robot control". Thesis, Toulouse, INSA, 2017. http://www.theses.fr/2017ISAT0028/document.
Testo completoAbstract (sommario):
Parmi les nombreuses recherches en matière de planification et de contrôle des mouvements pour des applications robotiques, l'humanité n'a jamais atteint un point où les robots seraient parfaitement fonctionnels et autonomes dans des environnements dynamiques. Bien qu'il soit controversé de discuter de la nécessité de ces robots, il est très important d'aborder les problèmes qui nous empêchent de réaliser un tel niveau d'autonomie. Ce travail de recherche tente de résoudre ces problèmes qui séparent ces deux modes de fonctionnement avec un accent particulier sur les incertitudes. Les impossibilités pratiques de capacités de détection précises entraînent une variété d'incertitudes dans les scénarios où le robot est mobile ou l'environnement est dynamique. Ce travail se concentre sur le développement de stratégies intelligentes pour améliorer la capacité de gérer les incertitudes de manière robuste dans les robots humanoïdes et industriels. Premièrement, nous nous concentrerons sur un cadre dynamique d'évitement d'obstacles proposé pour les robots industriels équipés de capteurs de peau pour la réactivité. La planification des chemins et le contrôle des mouvements sont généralement formalisés en tant que problèmes distincts de la robotique, bien qu'ils traitent fondamentalement du même problème. Les espaces de configuration à grande dimension, l'environnement changeant et les incertitudes ne permettent pas la planification en temps réel de mouvement exécutable. L'incapacité fondamentale d'unifier ces deux problèmes nous a amené à gérer la trajectoire planifiée en présence de perturbations et d'obstacles imprévus à l'aide de différents mécanismes d'exécution et de déformation de trajectoire. Le cadre proposé utilise «Stack of Tasks», un contrôleur hiérarchique utilisant des informations de proximité, grâce à un planificateur de chemin réactif utilisant un nuage de points pour éviter les obstacles. Les expériences sont effectuées avec les robots PR2 et UR5 pour vérifier la validité du procédé à la fois en simulation et in-situ. Deuxièmement, nous nous concentrons sur une stratégie pour modéliser les incertitudes des paramètres inertiels d'un robot humanoïde dans des scénarios de tâches d'équilibre. Le contrôle basé modèles est devenu de plus en plus populaire dans la communauté des robots à jambes au cours des dix dernières années. L'idée clé est d'exploiter un modèle du système pour calculer les commandes précises du moteur qui entraînent le mouvement désiré. Cela permet d'améliorer la qualité du suivi du mouvement, tout en utilisant des gains de rétroaction plus faibles, ce qui conduit à une conformité plus élevée. Cependant, le principal défaut de cette approche est généralement le manque de robustesse aux erreurs de modélisation. Dans ce manuscrit, nous nous concentrons sur la robustesse du contrôle de la dynamique inverse à des paramètres inertiels erronés. Nous supposons que ces paramètres sont connus, mais seulement avec une certaine précision. Nous proposons ensuite un contrôleur basé optimisation, rapide d'exécution, qui assure l'équilibre du robot malgré ces incertitudes. Nous avons utilisé ce contrôleur en simulation pour effectuer différentes tâches d'atteinte avec le robot humanoïde HRP-2, en présence de diverses erreurs de modélisation. Les comparaisons avec un contrôleur de dynamique inverse classique à travers des centaines de simulations montrent la supériorité du contrôleur proposé pour assurer l'équilibre du robotAmidst a lot of research in motion planning and control in concern with robotic applications, the mankind has never reached a point yet, where the robots are perfectly functional and autonomous in dynamic settings. Though it is controversial to discuss about the necessity of such robots, it is very important to address the issues that stop us from achieving such a level of autonomy. Industrial robots have evolved to be very reliable and highly productive with more than 1.5 million operational robots in a variety of industries. These robots work in static settings and they literally do what they are programmed for specific usecases, though the robots are flexible enough to be programmed for a variety of tasks. This research work makes an attempt to address these issues that separate both these settings in a profound way with special focus on uncertainties. Practical impossibilities of precise sensing abilities lead to a variety of uncertainties in scenarios where the robot is mobile or the environment is dynamic. This work focuses on developing smart strategies to improve the ability to handle uncertainties robustly in humanoid and industrial robots. First, we focus on a dynamical obstacle avoidance framework proposed for industrial robots equipped with skin sensors for reactivity. Path planning and motion control are usually formalized as separate problems in robotics. High dimensional configuration spaces, changing environment and uncertainties do not allow to plan real-time motion ahead of time requiring a controller to execute the planned trajectory. The fundamental inability to unify both these problems has led to handle the planned trajectory amidst perturbations and unforeseen obstacles using various trajectory execution and deformation mechanisms. The proposed framework uses ’Stack of Tasks’, a hierarchical controller using proximity information to avoid obstacles. Experiments are performed on a UR5 robot to check the validity of the framework and its potential use for collaborative robot applications. Second, we focus on a strategy to model inertial parameters uncertainties in a balance controller for legged robots. Model-based control has become more and more popular in the legged robots community in the last ten years. The key idea is to exploit a model of the system to compute precise motor commands that result in the desired motion. This allows to improve the quality of the motion tracking, while using lower feedback gains, leading so to higher compliance. However, the main flaw of this approach is typically its lack of robustness to modeling errors. In this paper we focus on the robustness of inverse-dynamics control to errors in the inertial parameters of the robot. We assume these parameters to be known, but only with a certain accuracy. We then propose a computationally-efficient optimization-based controller that ensures the balance of the robot despite these uncertainties. We used the proposed controller in simulation to perform different reaching tasks with the HRP-2 humanoid robot, in the presence of various modeling errors. Comparisons against a standard inverse-dynamics controller through hundreds of simulations show the superiority of the proposed controller in ensuring the robot balance
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Rogers, Andrew Charles. "Optimization-Based Guidance for Satellite Relative Motion". Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/79455.
Testo completoAbstract (sommario):
Spacecraft relative motion modeling and control promises to enable or augment a wide range of missions for scientific research, military applications, and space situational awareness. This dissertation focuses on the development of novel, optimization-based, control design for some representative relative-motion-enabled missions. Spacecraft relative motion refers to two (or more) satellites in nearly identical orbits. We examine control design for relative configurations on the scale of meters (for the purposes of proximity operations) as well as on the scale of tens of kilometers (representative of science gathering missions). Realistic control design for satellites is limited by accurate modeling of the relative orbital perturbations as well as the highly constrained nature of most space systems. We present solutions to several types of optimal orbital maneuvers using a variety of different, realistic assumptions based on the maneuver objectives.
Initially, we assume a perfectly circular orbit with a perfectly spherical Earth and analytically solve the under-actuated, minimum-energy, optimal transfer using techniques from optimal control and linear operator theory. The resulting open-loop control law is guaranteed to be a global optimum. Then, recognizing that very few, if any, orbits are truly circular, the optimal transfer problem is generalized to the elliptical linear and nonlinear systems which describe the relative motion. Solution of the minimum energy transfer for both the linear and nonlinear systems reveals that the resulting trajectories are nearly identical, implying that the nonlinearity has little effect on the relative motion. A continuous-time, nonlinear, sliding mode controller which tracks the linear trajectory in the presence of a higher fidelity orbit model shows that the closed-loop system is both asymptotically stable and robust to disturbances and un-modeled dynamics.
Next, a novel method of computing discrete-time, multi-revolution, finite-thrust, fuel-optimal, relative orbit transfers near an elliptical, perturbed orbit is presented. The optimal control problem is based on the classical, continuous-time, fuel-optimization problem from calculus of variations, and we present the discrete-time analogue of this problem using a transcription-based method. The resulting linear program guarantees a global optimum in terms of fuel consumption, and we validate the results using classical impulsive orbit transfer theory. The new method is shown to converge to classical impulsive orbit transfer theory in the limit that the duration of the zero-order hold discretization approaches zero and the time horizon extends to infinity. Then the fuel/time optimal control problem is solved using a hybrid approach which uses a linear program to solve the fuel optimization, and a genetic algorithm to find the minimizing time-of-flight. The method developed in this work allows mission planners to determine the feasibility for realistic spacecraft and motion models.
Proximity operations for robotic inspection have the potential to aid manned and unmanned systems in space situational awareness and contingency planning in the event of emergency. A potential limiting factor is the large number of constraints imposed on the inspector vehicle due to collision avoidance constraints and limited power and computational resources. We examine this problem and present a solution to the coupled orbit and attitude control problem using model predictive control. This control technique allows state and control constraints to be encoded as a mathematical program which is solved on-line. We present a new thruster constraint which models the minimum-impulse bit as a semi-continuous variable, resulting in a mixed-integer program. The new model, while computationally more expensive, is shown to be more fuel-efficient than a sub-optimal approximation. The result is a fuel efficient, trajectory tracking, model predictive controller with a linear-quadratic attitude regulator which tracks along a pre-computed ``safe'' trajectory in the presence of un-modeled dynamics on a higher fidelity orbital and attitude model.Ph. D.
Libri sul tema "Proximity-Based Control"
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MacDonald, G. Blake. A comparison of new proximity-based expressions of competing vegetation. Sault Ste-Marie: Ministry of Natural Resources, Ontario Forest Research Institute, 1991.
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United States. Agency for Toxic Substances and Disease Registry. Pancreatic cancer mortality and residential proximity to railroad refueling facilities in Montana: A records-based case-control pilot study. Atlanta, Ga: The Agency, 1994.
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Application of fuzzy logic-neural network based reinforcement learning to proximity and docking operations: Attitude control results. [Houston, Tex.]: Research Institute for Computing and Information Systems, University of Houston, Clear lake, 1992.
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van Hooft, Edwin. Self-Regulatory Perspectives in the Theory of Planned Job Search Behavior: Deliberate and Automatic Self-Regulation Strategies to Facilitate Job Seeking. A cura di Ute-Christine Klehe e Edwin van Hooft. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780199764921.013.31.
Testo completoAbstract (sommario):
Because job search often is a lengthy process accompanied by complexities, disruptions, rejections, and other adversities, job seekers need self-regulation to initiate and maintain job search behaviors for obtaining employment goals. This chapter reviews goal/intention properties (e.g., specificity, proximity, conflicts, motivation type) and skills, beliefs, strategies, and capacities (e.g., self-monitoring skills and type, trait and momentary self-control capacity, nonlimited willpower beliefs, implementation intentions, goal-shielding and goal maintenance strategies) that facilitate self-regulation and as such may moderate the relationship between job search intentions and job search behavior. For each moderator, a theoretical rationale is developed based on self-regulation theory linked to the theory of planned job search behavior, available empirical support is reviewed, and future research recommendations are provided. The importance of irrationality and nonconscious processes is discussed; examples are given of hypoegoic self-regulation strategies that reduce the need for deliberate self-regulation and conscious control by automatizing job search behaviors.
Capitoli di libri sul tema "Proximity-Based Control"
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Lang, Ulrich, e Rudolf Schreiner. "Proximity-Based Access Control (PBAC) using Model-Driven Security". In ISSE 2015, 157–70. Wiesbaden: Springer Fachmedien Wiesbaden, 2015. http://dx.doi.org/10.1007/978-3-658-10934-9_14.
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Oumer, Nassir W., e Giorgio Panin. "Camera-Based Tracking for Rendezvous and Proximity Operation of a Satellite". In Advances in Aerospace Guidance, Navigation and Control, 625–38. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-17518-8_36.
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Espiau, Bernard. "Sensory-Based Control Robustness Issues and Modelling Techniques Application to Proximity Sensing". In Kinematic and Dynamic Issues in Sensor Based Control, 3–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84012-8_1.
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Boecker, Martin. "Increasing Control Room Effectiveness and Security Through Proximity-Based Interaction Technologies". In Advances in Human Factors and System Interactions, 87–96. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-41956-5_9.
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Lu, Yao, e Yingmin Jia. "Characteristic Model-Based Adaptive Control for Spacecraft Rendezvous and Proximity Operations". In Proceedings of 2021 Chinese Intelligent Automation Conference, 228–36. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-6372-7_27.
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Ren, Hao, Bin Jiang, Yajie Ma e Gang Tao. "Multi-design Integration Based Adaptive Fault-Tolerant Control of Spacecraft Proximity Operations". In Lecture Notes in Electrical Engineering, 4543–55. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8155-7_376.
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Zhang, Xue, Sanglu Lu, Daoxu Chen e Li Xie. "PREG: A Practical Power Control Algorithm Based on a Novel Proximity Graph for Heterogeneous Wireless Sensor Networks". In Wireless Algorithms, Systems, and Applications, 620–31. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11814856_58.
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Dillon, Lisa, Alla Chernenko, Martin Dribe, Sacha Engelhardt, Alain Gagnon, Heidi A. Hanson, Huong Meeks, Luciana Quaranta, Ken R. Smith e Hélène Vézina. "20. Did Grandmothers Enhance Reproductive Success in Historic Populations?" In Human Evolutionary Demography, 475–502. Cambridge, UK: Open Book Publishers, 2024. http://dx.doi.org/10.11647/obp.0251.20.
Testo completoAbstract (sommario):
Human reproductive success requires both producing children and making investments in the development of offspring. To a large extent these investments are made by the parents of the child, but researchers are now looking beyond the nuclear family to understand how extended kin, notably grandmothers, enhance reproductive success by making transfers to progeny of different kinds. The extent to which kin influence fertility and mortality outcomes may vary across different socio-economic and geographic contexts; as a result, an international comparative framework is used here to sharpen our understanding of the role of kin in reproduction. This chapter assesses the role of grandmothers in fertility outcomes in a comparative historical demographic study based on data from Scandinavia and North America. The individual-level data used are all longitudinal and multigenerational, allowing us to address the impact of maternal and paternal grandmothers on the fertility of their daughters and daughters-in-law. Attending to heterogeneous effects across space and time as well as within-family differences via the use of fixed effects models, we discover broader associations of the paternal grandmother with higher fertility across the four regions. We also find a general fertility advantage associated with the post-reproductive availability or recent death of the maternal grandmother in the four populations. Important variations across regions nevertheless exist in terms of the strength of the association and the importance of the grandmother’s proximity. Our interpretation is that grandmothers were generally associated with high-fertility outcomes, but that the mechanism for this association was co-determined by family configurations, resource allocation and the advent of fertility control.
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Rüppel, Adrian Karl, Muzaffer Ay, Benedikt Biernat, Ike Kunze, Markus Landwehr, Samuel Mann, Jan Pennekamp et al. "Model-Based Controlling Approaches for Manufacturing Processes". In Internet of Production, 1–26. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-030-98062-7_7-2.
Testo completoAbstract (sommario):
AbstractThe main objectives in production technology are quality assurance, cost reduction, and guaranteed process safety and stability. Digital shadows enable a more comprehensive understanding and monitoring of processes on shop floor level. Thus, process information becomes available between decision levels, and the aforementioned criteria regarding quality, cost, or safety can be included in control decisions for production processes. The contextual data for digital shadows typically arises from heterogeneous sources. At shop floor level, the proximity to the process requires usage of available data as well as domain knowledge. Data sources need to be selected, synchronized, and processed. Especially high-frequency data requires algorithms for intelligent distribution and efficient filtering of the main information using real-time devices and in-network computing. Real-time data is enriched by simulations, metadata from product planning, and information across the whole process chain. Well-established analytical and empirical models serve as the base for new hybrid, gray box approaches. These models are then applied to optimize production process control by maximizing the productivity under given quality and safety constraints. To store and reuse the developed models, ontologies are developed and a data lake infrastructure is utilized and constantly enlarged laying the basis for a World Wide Lab (WWL). Finally, closing the control loop requires efficient quality assessment, immediately after the process and directly on the machine. This chapter addresses works in a connected job shop to acquire data, identify and optimize models, and automate systems and their deployment in the Internet of Production (IoP).
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Rüppel, Adrian Karl, Muzaffer Ay, Benedikt Biernat, Ike Kunze, Markus Landwehr, Samuel Mann, Jan Pennekamp et al. "Model-Based Controlling Approaches for Manufacturing Processes". In Internet of Production, 1–26. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-030-98062-7_7-1.
Testo completoAbstract (sommario):
AbstractThe main objectives in production technology are quality assurance, cost reduction, and guaranteed process safety and stability. Digital shadows enable a more comprehensive understanding and monitoring of processes on shop floor level. Thus, process information becomes available between decision levels, and the aforementioned criteria regarding quality, cost, or safety can be included in control decisions for production processes. The contextual data for digital shadows typically arises from heterogeneous sources. At shop floor level, the proximity to the process requires usage of available data as well as domain knowledge. Data sources need to be selected, synchronized, and processed. Especially high-frequency data requires algorithms for intelligent distribution and efficient filtering of the main information using real-time devices and in-network computing. Real-time data is enriched by simulations, metadata from product planning, and information across the whole process chain. Well-established analytical and empirical models serve as the base for new hybrid, gray box approaches. These models are then applied to optimize production process control by maximizing the productivity under given quality and safety constraints. To store and reuse the developed models, ontologies are developed and a data lake infrastructure is utilized and constantly enlarged laying the basis for a World Wide Lab (WWL). Finally, closing the control loop requires efficient quality assessment, immediately after the process and directly on the machine. This chapter addresses works in a connected job shop to acquire data, identify and optimize models, and automate systems and their deployment in the Internet of Production (IoP).
Atti di convegni sul tema "Proximity-Based Control"
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Choi, Sunoh, Christopher Gutierrez, Hyo-Sang Lim, Saurabh Bagchi e Elisa Bertino. "Secure and resilient proximity-based access control". In the 2013 international workshop. New York, New York, USA: ACM Press, 2013. http://dx.doi.org/10.1145/2512410.2512425.
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Kim, Yu Seung, e Patrick Tague. "Proximity-based wireless access control through considerate jamming". In MobiCom'14: The 20th Annual International Conference on Mobile Computing and Networking. New York, NY, USA: ACM, 2014. http://dx.doi.org/10.1145/2646584.2646588.
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Rasmussen, Kasper Bonne, Claude Castelluccia, Thomas S. Heydt-Benjamin e Srdjan Capkun. "Proximity-based access control for implantable medical devices". In the 16th ACM conference. New York, New York, USA: ACM Press, 2009. http://dx.doi.org/10.1145/1653662.1653712.
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Mantegazza, Dario, Jerome Guzzi, Luca M. Gambardella e Alessandro Giusti. "Learning Vision-Based Quadrotor Control in User Proximity". In 2019 14th ACM/IEEE International Conference on Human-Robot Interaction (HRI). IEEE, 2019. http://dx.doi.org/10.1109/hri.2019.8673022.
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Thomas, John, Francois Pasteau e Francois Chaumette. "Plane-to-Plane Positioning by Proximity-based Control". In 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). IEEE, 2022. http://dx.doi.org/10.1109/iros47612.2022.9981781.
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Chai, Yi, Zhimin Yang, Kunpeng Wang e Ke Zhang. "Proximity operator based alternating iteration algorithm for sparse signal recovery". In 2014 33rd Chinese Control Conference (CCC). IEEE, 2014. http://dx.doi.org/10.1109/chicc.2014.6896199.
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DeLellis, Pietro, Franco Garofalo e Francesco Lo Iudice. "Formation control on Jordan curves based on noisy proximity measurements". In 2019 18th European Control Conference (ECC). IEEE, 2019. http://dx.doi.org/10.23919/ecc.2019.8795641.
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Ulrich, Steve, e Kirk Hovell. "Iterative Learning Control of Spacecraft Proximity Operations Based on Confidence Level". In AIAA Guidance, Navigation, and Control Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2017. http://dx.doi.org/10.2514/6.2017-1046.
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Li, Chi, Rolando Burgos, Ye Tang e Dushan Boroyevich. "Impedance-based stability analysis of multiple STATCOMs in proximity". In 2016 IEEE 17th Workshop on Control and Modeling for Power Electronics (COMPEL). IEEE, 2016. http://dx.doi.org/10.1109/compel.2016.7556744.
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Gaikwad, Ragini, Sidhesh Mohite Mayuri Kharat e Jayendra Thakur. "PLC based automatic car washing system using proximity sensors". In 2017 IEEE International Conference on Power, Control, Signals and Instrumentation Engineering (ICPCSI). IEEE, 2017. http://dx.doi.org/10.1109/icpcsi.2017.8392041.
Testo completoRapporti di organizzazioni sul tema "Proximity-Based Control"
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Soramäki, Kimmo. Financial Cartography. FNA, ottobre 2019. http://dx.doi.org/10.69701/ertx8007.
Testo completoAbstract (sommario):
Geographic maps have been of military and economic importance throughout the ages. Rulers have commissioned maps to control the financial, economic, political, and military aspects of their sovereign entities. Large scale projects like the Ordnance Survey in the UK in the late 18th century, and the Lewis and Clark Expedition a few decades later to map the American West, are early examples of trailblazing efforts to create accurate modern maps of high strategic importance. Digitalization, globalization, and a larger urban and educated workforce necessitate a new understanding of the world, beyond traditional maps based on geographic features. Many of today's most critical threats know no geographic borders. For instance, cyber attacks can be orchestrated through globally distributed bot networks; just-in-time manufacturing relies on the free flow of goods across jurisdictions; global markets and the infrastructures that support them relay information and price signals globally within seconds. A lack of understanding financial interdependencies was clearly demonstrated by the freezing of credit markets in the last financial crisis and the uncertainty created by Brexit. Ten years after the financial crisis, we are still only beginning to map, model and visualise these critical maps of the financial world. We call for attention to work on a large scale project of "Financial Cartography" to address this gap. In financial cartography, we replace geographic proximity with logical proximity, such as financial interdependence, similarity (e.g., of portfolio or income streams), a flow of transactions or a magnitude of exposures. Similar to geographic maps, financial maps will find many important uses across business, government and military domains. Critically, they are needed for protection and projection of state power, for optimizing and managing risks in business, and in making policy decisions related to the major challenges of climate change, mass migration and geopolitical instability. Fundamentally, cartography is a way that reality can be modeled to communicate information on “big data” sets. Cartography allows one to simplify and reduce the complexity of the data to highlight salient features of the data, and to filter out noise. This makes maps ideal devices to increase the bandwidth by which information can be communicated to its users, for making quick decision based on complex data. In the following pages, we make a case and provide starting points for a research agenda around "Financial Cartography" in three interrelated parts: Maps of Trade Networks Maps of Financial Markets and Maps of Financial Market Infrastructures
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Leis e Mohan. L51803 Failure Criterion for Stress-Corrosion Cracking in Pipelines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), settembre 1995. http://dx.doi.org/10.55274/r0010327.
Testo completoAbstract (sommario):
Failures due to stress-corrosion cracking (SCC) generally involve several adjacent, parallel, deep cracks that because of their proximity coalesce to form long flaws, which can cause ruptures.Recent studies indicate that such multiple flaws cause a local increase in compliance as compared to a single crack that represents the largest of the cracks involved.This means that the failure pressure for such a group of cracks can be poorly represented by a single flaw failure criterion, such as the Pipe Axial Flaw Failure Criterion (PAFFC) developed for the Pipeline Research Council International, Inc. The objective of this project was to develop a failure criterion for the multiple flaw situations typical of SCC based on available literature data for a repeating pattern of cracks (a regular array of cracks). This report begins with a discussion of predicted failure pressures for several typical field failures due to SCC. This discussion clearly demonstrates significant errors in predicted failure pressure for the multiple cracking typical of SCC when the failure pressure is predicted in terms of available single-flaw failure criteria for part-through-wall flaws in pipelines. This is followed by an analysis based on available literature data. It is shown that the literature data fail to represent the essential features of typical patches of cracks that control SCC failures. Analysis representing realistic cracking patterns is then introduced and used in conjunction with PAFFC to show that very accurate predictions can be made if the typical nature of the SCC patch is embedded in the failure criterion.
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Regan, Jack, Julie Bryant e Craig Weinschenk. Analysis of the Coordination of Suppression and Ventilation in Single-Family Homes. UL Firefighter Safety Research Institute, marzo 2020. http://dx.doi.org/10.54206/102376/slzh7498.
Testo completoAbstract (sommario):
Prior full-scale research with the fire service was primarily designed to isolate specific tactics, most often either ventilation or suppression, which allowed researchers to develop science-based recommendations related to the specific components of fireground operations studied in relatively controlled conditions. The current project went beyond earlier research by conducting twenty experiments in eight acquired, single-family residential structures and that combined fireground tactics to quantify the impact of coordination between ventilation and suppression actions. This experimental series included second-story bedroom fires (14 experiments) and first-floor kitchen fires (6 experiments). The main control variables studied included the position of initial application of water, the ventilation method, and the timing of ventilation relative to water application. The ventilation tactics examined in these experiments included horizontal, vertical, positive pressure, and hydraulic ventilation, while the suppression tactics included both interior water application and initial exterior water application followed by interior water application. While some elements of the experiments (e.g. structure floor plan and weather) resulted in increased variability, the lessons learned highlighted the importance of having a systematic approach to the implementation of tactics. Most importantly, there was no meaningful increase in temperature outside of fire rooms when ventilation tactics were executed in coordination with (shortly after or shortly before) the onset of suppression. The effectiveness of suppression actions in extinguishing the fire were dependent on the ability of those actions to 1) cool surfaces in the fire room and 2) wet unburned fuel. Exterior suppression actions on second-floor bedroom fires resulted in a decrease in temperatures throughout the second floor, followed by regrowth prior to final suppression through interior streams. When exterior suppression was performed on first-floor kitchen fires, where more complete fuel wetting was possible, regrowth was not observed prior to interior suppression. When surface cooling or fuel wetting are not possible due to the elevation of the fire room, missing ceiling, or obstacles, firefighters should consider alternative means of water distribution to improve the effectiveness of suppression actions from outside the fire room. Suppression actions, whether interior or exterior, generally resulted in a decrease in temperatures and gas concentrations at locations where occupants may potentially be located. Conditions improved most quickly at locations closest in proximity to the inlet of the flow path established between the front door and the fire room. For this reason, opening an exterior door to gain access should be thought of as an important ventilation action, both in terms of its potential to cause fire growth and its potential to improve conditions for potentially trapped occupants. After effective suppression, structure ventilation operations should similarly be cognizant of gas flows, with the aim of establishing flow throughout all areas where occupants may be located.