759 research outputs found

    Control and Model-Aided Inertial Navigation of a Nonholonomic Vehicle

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    International audienceThe present work deals with the control and localization problem of wheeled-mobile robots with nonholonomic constraints. In the proposed method a simple nonlinear control law, composed of a position and heading direction controller, is designed to asymptotically stabilize the position error. The control law takes into account the constraints on the control signals in order to avoid saturation of the actuators. Furthermore, this paper considers a method of using the dynamic vehicle model and vehicle's nonholonomic constraints in order to aid position and attitude estimates provided by an Inertial Navigation System (INS). It is shown that dynamic model and vehicle's nonholonomic constraints can reduce the error growth in robot position estimates. Simulations are included to confirm the effectiveness of the proposed scheme

    Distributed event-triggered communication for angular speed synchronization of networked BLDC motors

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    [EN] This work presents the design and implementation of a collaborative and decentralized control for synchronizing the angular velocity of a group of spatially distributed brushless direct current (BLDC) motors. Via an Active Disturbance Rejection Control (ADRC), acting as an internal-loop, the dynamics of the BLDC can be assimilated to that of a first-order integrator, which is considered an agent. Then, a decentralized collaborative control strategy with event-triggered communication is proposed, which solves the problem of leader-follower consensus for the multi-agent system and thus speed synchronization. The communication topology between agents is modeled using an undirected and connected graph. The decentralized control law incorporates an event function, which indicates the instant at which the i-th agent transmits the angular velocity information to its neighbor. An experimental platform using two BLDC and a virtual leader was developed to validate the proposed approach. The experimental results show excellent performance for angular velocity consensus for regulation tasks, while the bandwidth usage is only 1.25 % regarding a periodic communication implementation.[ES] Este trabajo presenta el diseño e implementación de un control colaborativo descentralizado para la sincronización de velocidad angular de un conjunto de motores de corriente continua sin escobillas (BLDC) distribuidos espacialmente. Apoyándose de un control por rechazo activo de perturbaciones, actuando como un bucle interno, la dinámica del BLDC puede asimilarse a la de un integrador de primer orden y el cual será considerado un agente. Se propone entonces una estrategia de control colaborativo descentralizado con una comunicación activada por eventos, que resuelve el problema del consenso líder-seguidor del sistema multi-agente y, con ello, la sincronización de velocidades entre motores. La topología de comunicación entre agentes se modela usando un grafo conectado y no dirigido. La ley de control descentralizado incorpora una función de evento, que indica el instante en el que ii-ésimo agente transmite la información de velocidad angular a su vecino. El intercambio asíncrono de información permite reducir el tráfico de datos en la red de comunicaciones, lo que permite aprovechar el ancho de banda. Al analizar la dinámica de la trayectoria del error del sistema, se establece que el vector de error del sistema multi-agente tiende de forma exponencial y permanece confinado a una vecindad del origen del espacio de estados de error. Aunque la estrategia está diseñada para n-agentes, se desarrolló una plataforma experimental compuesta por dos motores y un líder virtual, permitiendo validar la estrategia. Los resultados experimentales muestran un excelente desempeño del consenso de velocidad angular de ambos motores BLDC para tareas de regulación, mientras que el uso del ancho de banda es de solamente 1.25 % con respecto a una implementación de comunicación periódica.Hernández-Méndez, A.; Guerrero-Castellanos, J.; Orozco-Urbieta, T.; Linares-Flores, J.; Mino-Aguilar, G.; Curiel, G. (2021). Comunicación distribuida activada por eventos para la sincronización de velocidad angular de motores BLDC en red. Revista Iberoamericana de Automática e Informática industrial. 18(4):360-370. https://doi.org/10.4995/riai.2021.14989OJS360370184Ahmed, N., Cortes, J., Martinez, S., 2016. Distributed control and estimation of robotic vehicle networks: Overview of the special issue-part II. IEEE Control Systems 36 (4), 18-21. https://doi.org/10.1109/MCS.2016.2558398Aranda-Escolástico, E., Guinaldo, M., Heradio, R., Chacon, J., Vargas, H., Sánchez, J., Dormido, S., 2020. Event-based control: A bibliometric analysis of twenty years of research. IEEE Access 8, 47188-47208. https://doi.org/10.1109/ACCESS.2020.2978174Bullo, F., Cortés, J., Martinez, S., 2009. Distributed Control of Robotic Networks: A Mathematical Approach to Motion Coordination Algorithms: A Mathematical Approach to Motion Coordination Algorithms. Princeton University Press.https://doi.org/10.1515/9781400831470Chaari, R., Ellouze, F., Koubaa, A., Qureshi, B., Pereira, N., Youssef, H., Tovar, E., 2016. Cyber-physical systems clouds: A survey. Computer Networks 108, 260 - 278. https://doi.org/10.1016/j.comnet.2016.08.017Dimarogonas, D. V., Frazzoli, E., 2009. Distributed event-triggered control strategies for multi-agent systems. In: Communication, Control, and Computing, 2009. Allerton 2009. 47th Annual Allerton Conference on. IEEE, pp. 906-910. https://doi.org/10.1109/ALLERTON.2009.5394897Fuentes, G. A. R., Cortés-Romero, J. A., Zou, Z., Costa-Castelló, R., Zhou, K., 2015. Power active filter control based on a resonant disturbance observer. IET Power Electronics 8 (4), 554-564. https://doi.org/10.1049/iet-pel.2014.0032Garcia, E., Cao, Y., Wang, X., Casbeer, D. W., July 2015. Decentralized eventtriggered consensus of linear multi-agent systems under directed graphs. In: 2015 American Control Conference (ACC). pp. 5764-5769. https://doi.org/10.1109/ACC.2015.7172242Guerrero-Castellanos, J., Rifaï, H., Arnez-Paniagua, V., Linares-Flores, J., Saynes-Torres, L., Mohammed, S., 2018. Robust active disturbance rejection control via control lyapunov functions: Application to actuated-ankle-footorthosis. Control Engineering Practice 80, 49 - 60. https://doi.org/10.1016/j.conengprac.2018.08.008Guerrero-Castellanos, J., Vega-Alonzo, A., Durand, S., Marchand, N., Gonzalez-Diaz, V., Casta˜neda-Camacho, J., Guerrero-Sánchez, W., 2019. Leader-following consensus and formation control of vtol-uavs with eventtriggered communications. Sensors 19 (24), 1-26. https://doi.org/10.3390/s19245498Guinaldo, M., Dimarogonas, D. V., Johansson, K. H., S'anchez, J., Dormido, S., 2013. Distributed event-based control strategies for interconnected linear systems. Control Theory & Applications, IET 7 (6), 877-886. https://doi.org/10.1049/iet-cta.2012.0525Guzey, H. M., Dumlu, A., Guzey, N., Alpay, A., April 2018. Optimal synchronizing speed control of multiple dc motors. In: 2018 4th International Conference on Optimization and Applications (ICOA). pp. 1-5. https://doi.org/10.1109/ICOA.2018.8370508Han, J., 2009. From pid to active disturbance rejection control. Transactions on Industry Electronics 56 (3), 900-906. https://doi.org/10.1109/TIE.2008.2011621Hebertt Sira-Ramírez, Alberto Luviano-Juárez, M. R.-N. E.-W. Z.-B., 2017. Active Disturbance Rejection Control of Dynamic Systems. Butterworth- Heinemann.Hernandez-Méndez, A., Linares-Flores, J., Sira-Ramírez, H., Guerrero-Castellanos, J., Mino-Aguilar, G., 2017. A backstepping approach to decentralized active disturbance rejection control of interacting boost converters. Transactions on Industry Applications 53 (4), 4063-4072. https://doi.org/10.1109/TIA.2017.2683441Lee, J., Bagheri, B., Kao, H.-A., 2015. A cyber-physical systems architecture for industry 4.0-based manufacturing systems. Manufacturing Letters 3, 18- 23. https://doi.org/10.1016/j.mfglet.2014.12.001Lewis, F. L., Zhang, H., Hengster-Movric, K., Das, A., 2013. Cooperative control of multi-agent systems: optimal and adaptive design approaches. Springer Science & Business Media. https://doi.org/10.1007/978-1-4471-5574-4Marchand, N., Durand, S., Guerrero-Castellanos, J. F., 2013. A general formula for event-based stabilization of nonlinear systems. Automatic Control, IEEE Transactions on 58 (5), 1332-1337. https://doi.org/10.1109/TAC.2012.2225493Miskowicz, M., 2015. Event-Based Control and Signal Processing. CRC Press.Neenu, T., Poongodi, P., 07 2009. Position control of dc motor using genetic algorithm based pid controller. Lecture Notes in Engineering and Computer Science 2177.Olfati-Saber, R., Murray, R. M., 2004a. Consensus problems in networks of agents with switching topology and time-delays. Automatic Control, IEEE Transactions on 49 (9), 1520-1533. https://doi.org/10.1109/TAC.2004.834113Olfati-Saber, R., Murray, R. M., Sep. 2004b. Consensus problems in networks of agents with switching topology and time-delays. IEEE Transactions on Automatic Control 49 (9), 1520-1533. https://doi.org/10.1109/TAC.2004.834113Ren, W., Beard, R. W., 2008. Distributed consensus in multi-vehicle cooperative control. Springer. https://doi.org/10.1007/978-1-84800-015-5Sánchez-Santana, J., Guerrero-Castellanos, J., Villarreal-Cervantes, M., Ramırez-Martınez, S., 2018. Control distribuido y disparado por eventos para la formación de robots m'oviles tipo (3, 0)?. In: Congreso Nacional de Control Automático.Seyboth, G. S., Dimarogonas, D. V., Johansson, K. H., 2013. Event-based broadcasting for multi-agent average consensus. Automatica 49 (1), 245-252. https://doi.org/10.1016/j.automatica.2012.08.042Shi, T., Liu, H., Geng, Q., Xia, C., 2016. Improved relative coupling control structure for multi-motor speed synchronous driving system. IET Electric Power Applications 10 (6), 451-457. https://doi.org/10.1049/iet-epa.2015.0515Sira-Ramírez, H., Hernández-Méndez, A., Linares-Flores, J., Luviano-Juarez, A., 2016. Robust flat filtering dsp based control of the boost converter. Control Theory and Technology 14 (3), 224-236. https://doi.org/10.1007/s11768-016-6025-6Sira-Ramírez, H., Linares-Flores, J., Luviano-Juárez, A., Cortés-Romero, J., 2015. Ultramodelos globales y el control por rechazo activo de perturbaciones en sistemas no lineales diferencialmente planos. Revista Iberoamericanade Automática e Informática Industrial RIAIg 12 (2), 133 - 144. https://doi.org/10.1016/j.riai.2015.02.001Song, H., Rawat, D. B., Jeschke, S., Brecher, C., 2017. Front matter. In: Cyber- Physical Systems. Intelligent Data-Centric Systems. Academic Press, Boston, pp. i - ii.Sun, J., Liu, R., Luo, Y., Sun, W., 2009. Research on multi-motor synchronization control for cutter head of shield machine based on the ring coupled control strategy. In: Xie, M., Xiong, Y., Xiong, C., Liu, H., Hu, Z. (Eds.), Intelligent Robotics and Applications. Springer Berlin Heidelberg, Berlin, Heidelberg, pp. 345-354. https://doi.org/10.1007/978-3-642-10817-4_34Tao, L., Chen, Q., Nan, Y., Dong, F., Jin, Y., 09 2018. Speed tracking and synchronization of a multimotor system based on fuzzy adrc and enhanced adjacent coupling scheme. Complexity 2018, 1-16. https://doi.org/10.1155/2018/5632939Torres, F. J., Guerrero, G. V., García, C. D., Gomez, J. F., Adam, M., Escobar, R. F., Sep. 2016. Master-slave synchronization of robot manipulators driven by induction motors. IEEE Latin America Transactions 14 (9), 3986-3991. https://doi.org/10.1109/TLA.2016.7785923Valenzuela, A., Lorenz, R., 02 2001. Electronic line-shafting control for paper machine drives. Industry Applications, IEEE Transactions on 37, 158 - 164. https://doi.org/10.1109/28.903141Xia, C. L., 2012. Permanent magnet brushless DC motor drives and controls. John Wiley & Sons. https://doi.org/10.1002/9781118188347Xie, D., Xu, S., Zhang, B., Li, Y., Chu, Y., 2016. Consensus for multi-agent systems with distributed adaptive control and an event-triggered communication strategy. IET Control Theory Applications 10 (13), 1547-1555. https://doi.org/10.1049/iet-cta.2015.1221Yang, D., Ren,W., Liu, X., Dec 2014. Decentralized consensus for linear multiagent systems under general directed graphs based on event-triggered/selftriggered strategy. In: 53rd IEEE Conference on Decision and Control. pp. 1983-1988. https://doi.org/10.1109/CDC.2014.7039689Yu, H., Xi, J.-Q., Zhang, F., Hu, Y.-h., 02 2014. Research on gear shifting process without disengaging clutch for a parallel hybrid electric vehicle equipped with amt. Mathematical Problems in Engineering 2014, 1-12. https://doi.org/10.1155/2014/985652Zhang, C., Wu, H., He, J., Xu, C., 2015. Consensus tracking for multi-motor system via observer based variable structure approach. Journal of the Franklin Institute 352 (8), 3366 - 3377, special Issue on Advances in Nonlinear Dynamics and Control. https://doi.org/10.1016/j.jfranklin.2015.01.035Zhang, C.-H., Shi, Q.-S., Cheng, J., 01 2007. Design of fuzzy neural network controller for synchronization drive in multi-motor systems 22, 30-34.Zhang, X., Zhang, J., 2014. Distributed event-triggered control of multiagent systems with general linear dynamics. Journal of Control Science and Engineering 2014, 7. https://doi.org/10.1155/2014/698546Zhao, D., Li, C., Ren, J., 12 2009a. Speed synchronization of multiple induction motors with adjacent cross coupling control. pp. 6805-6810.Zhao, D.-Z., wen LI, C., REN, J., 2009b. Speed synchronization of multiple induction motors with total sliding mode control. Systems Engineering - Theory & Practice 29 (10), 110 - 117. https://doi.org/10.1016/S1874-8651(10)60077-4Zhao, G., Zhuang, B., Zheng, G., Zhao, Y., 09 2017. Cross-coupling control method for five-axis computer numerical control machine with dual rotary tables. Advances in Mechanical Engineering 9. https://doi.org/10.1177/1687814017733689Zhou, F., Huang, Z., Yang, Y., Wang, J., Li, L., Peng, J., 2017. Decentralized event-triggered cooperative control for multi-agent systems with uncertain dynamics using local estimators. Neurocomputing 237, 388 - 396. https://doi.org/10.1016/j.neucom.2017.01.02

    Comparative effectiveness and safety of non-vitamin K antagonists for atrial fibrillation in clinical practice: GLORIA-AF Registry

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    Comparative effectiveness and safety of non-vitamin K antagonists for atrial fibrillation in clinical practice: GLORIA-AF Registry

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    Background and purpose: Prospectively collected data comparing the safety and effectiveness of individual non-vitamin K antagonists (NOACs) are lacking. Our objective was to directly compare the effectiveness and safety of NOACs in patients with newly diagnosed atrial fibrillation (AF). Methods: In GLORIA-AF, a large, prospective, global registry program, consecutive patients with newly diagnosed AF were followed for 3 years. The comparative analyses for (1) dabigatran vs rivaroxaban or apixaban and (2) rivaroxaban vs apixaban were performed on propensity score (PS)-matched patient sets. Proportional hazards regression was used to estimate hazard ratios (HRs) for outcomes of interest. Results: The GLORIA-AF Phase III registry enrolled 21,300 patients between January 2014 and December 2016. Of these, 3839 were prescribed dabigatran, 4015 rivaroxaban and 4505 apixaban, with median ages of 71.0, 71.0, and 73.0 years, respectively. In the PS-matched set, the adjusted HRs and 95% confidence intervals (CIs) for dabigatran vs rivaroxaban were, for stroke: 1.27 (0.79–2.03), major bleeding 0.59 (0.40–0.88), myocardial infarction 0.68 (0.40–1.16), and all-cause death 0.86 (0.67–1.10). For the comparison of dabigatran vs apixaban, in the PS-matched set, the adjusted HRs were, for stroke 1.16 (0.76–1.78), myocardial infarction 0.84 (0.48–1.46), major bleeding 0.98 (0.63–1.52) and all-cause death 1.01 (0.79–1.29). For the comparison of rivaroxaban vs apixaban, in the PS-matched set, the adjusted HRs were, for stroke 0.78 (0.52–1.19), myocardial infarction 0.96 (0.63–1.45), major bleeding 1.54 (1.14–2.08), and all-cause death 0.97 (0.80–1.19). Conclusions: Patients treated with dabigatran had a 41% lower risk of major bleeding compared with rivaroxaban, but similar risks of stroke, MI, and death. Relative to apixaban, patients treated with dabigatran had similar risks of stroke, major bleeding, MI, and death. Rivaroxaban relative to apixaban had increased risk for major bleeding, but similar risks for stroke, MI, and death. Registration: URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01468701, NCT01671007. Date of registration: September 2013

    Anticoagulant selection in relation to the SAMe-TT2R2 score in patients with atrial fibrillation. the GLORIA-AF registry

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    Aim: The SAMe-TT2R2 score helps identify patients with atrial fibrillation (AF) likely to have poor anticoagulation control during anticoagulation with vitamin K antagonists (VKA) and those with scores >2 might be better managed with a target-specific oral anticoagulant (NOAC). We hypothesized that in clinical practice, VKAs may be prescribed less frequently to patients with AF and SAMe-TT2R2 scores >2 than to patients with lower scores. Methods and results: We analyzed the Phase III dataset of the Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF), a large, global, prospective global registry of patients with newly diagnosed AF and ≥1 stroke risk factor. We compared baseline clinical characteristics and antithrombotic prescriptions to determine the probability of the VKA prescription among anticoagulated patients with the baseline SAMe-TT2R2 score >2 and ≤ 2. Among 17,465 anticoagulated patients with AF, 4,828 (27.6%) patients were prescribed VKA and 12,637 (72.4%) patients an NOAC: 11,884 (68.0%) patients had SAMe-TT2R2 scores 0-2 and 5,581 (32.0%) patients had scores >2. The proportion of patients prescribed VKA was 28.0% among patients with SAMe-TT2R2 scores >2 and 27.5% in those with scores ≤2. Conclusions: The lack of a clear association between the SAMe-TT2R2 score and anticoagulant selection may be attributed to the relative efficacy and safety profiles between NOACs and VKAs as well as to the absence of trial evidence that an SAMe-TT2R2-guided strategy for the selection of the type of anticoagulation in NVAF patients has an impact on clinical outcomes of efficacy and safety. The latter hypothesis is currently being tested in a randomized controlled trial. Clinical trial registration: URL: https://www.clinicaltrials.gov//Unique identifier: NCT01937377, NCT01468701, and NCT01671007

    Search for resonant WZ production in the fully leptonic final state in proton–proton collisions at √s=13 TeV with the ATLAS detector

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    A search for a WZ resonance, in the fully leptonic final state (electrons or muons), is performed using 139 fb - 1 of data collected at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The results are interpreted in terms of a singly charged Higgs boson of the Georgi–Machacek model, produced by WZ fusion, and of a Heavy Vector Triplet, with the resonance produced by WZ fusion or the Drell–Yan process. No significant excess over the Standard Model prediction is observed and limits are set on the production cross-section times branching ratio as a function of the resonance mass for these processes

    Measurement of exclusive pion pair production in proton–proton collisions at √s=7 TeV with the ATLAS detector

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    The exclusive production of pion pairs in the process pp→ ppπ+π- has been measured at s=7TeV with the ATLAS detector at the LHC, using 80μb-1 of low-luminosity data. The pion pairs were detected in the ATLAS central detector while outgoing protons were measured in the forward ATLAS ALFA detector system. This represents the first use of proton tagging to measure an exclusive hadronic final state at the LHC. A cross-section measurement is performed in two kinematic regions defined by the proton momenta, the pion rapidities and transverse momenta, and the pion–pion invariant mass. Cross-section values of 4.8±1.0(stat)-0.2+0.3(syst)μb and 9±6(stat)-2+2(syst)μb are obtained in the two regions; they are compared with theoretical models and provide a demonstration of the feasibility of measurements of this type

    A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery

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    The standard model of particle physics1–4 describes the known fundamental particles and forces that make up our Universe, with the exception of gravity. One of the central features of the standard model is a field that permeates all of space and interacts with fundamental particles5–9. The quantum excitation of this field, known as the Higgs field, manifests itself as the Higgs boson, the only fundamental particle with no spin. In 2012, a particle with properties consistent with the Higgs boson of the standard model was observed by the ATLAS and CMS experiments at the Large Hadron Collider at CERN10,11. Since then, more than 30 times as many Higgs bosons have been recorded by the ATLAS experiment, enabling much more precise measurements and new tests of the theory. Here, on the basis of this larger dataset, we combine an unprecedented number of production and decay processes of the Higgs boson to scrutinize its interactions with elementary particles. Interactions with gluons, photons, and W and Z bosons—the carriers of the strong, electromagnetic and weak forces—are studied in detail. Interactions with three third-generation matter particles (bottom (b) and top (t) quarks, and tau leptons (τ)) are well measured and indications of interactions with a second-generation particle (muons, μ) are emerging. These tests reveal that the Higgs boson discovered ten years ago is remarkably consistent with the predictions of the theory and provide stringent constraints on many models of new phenomena beyond the standard model

    Measurement of the nuclear modification factor of b-jets in 5.02 TeV Pb+Pb collisions with the ATLAS detector

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    This paper presents a measurement of b-jet production in Pb+Pb and pp collisions at √sNN = 5.02 TeV with the ATLAS detector at the LHC. The measurement uses 260 pb−1 of pp collisions collected in 2017 and 1.4 nb−1 of Pb+Pb collisions collected in 2018. In both collision systems, jets are reconstructed via the anti-kt algorithm. The b-jets are identified from a sample of jets containing muons from the semileptonic decay of b-quarks using template fits of the muon momentum relative to the jet axis. In pp collisions, b-jets are reconstructed for radius parameters R = 0.2 and R = 0.4, and only R = 0.2 jets are used in Pb+Pb collisions. For comparison, inclusive R = 0.2 jets are also measured using 1.7 nb−1 of Pb+Pb collisions collected in 2018 and the same pp collision data as the b-jet measurement. The nuclear modification factor, RAA, is calculated for both b-jets and inclusive jets with R = 0.2 over the transverse momentum range of 80–290 GeV. The nuclear modification factor for b-jets decreases from peripheral to central collisions. The ratio of the b-jet RAA to inclusive jet RAA is also presented and suggests that the RAA for b-jets is larger than that for inclusive jets in central Pb+Pb collisions. The measurements are compared with theoretical calculations and suggest a role for mass and colour-charge effects in partonic energy loss in heavy-ion collisions

    Constraints on Higgs boson properties using WW∗(→ eνμν) jj production in 36.1fb-1 of √s=13 TeV pp collisions with the ATLAS detector

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    This article presents the results of two studies of Higgs boson properties using the WW∗(→ eνμν) jj final state, based on a dataset corresponding to 36.1 fb - 1 of s=13 TeV proton–proton collisions recorded by the ATLAS experiment at the Large Hadron Collider. The first study targets Higgs boson production via gluon–gluon fusion and constrains the CP properties of the effective Higgs–gluon interaction. Using angular distributions and the overall rate, a value of tan (α) = 0.0 ± 0.4 (stat.) ± 0.3 (syst.) is obtained for the tangent of the mixing angle for CP-even and CP-odd contributions. The second study exploits the vector-boson fusion production mechanism to probe the Higgs boson couplings to longitudinally and transversely polarised W and Z bosons in both the production and the decay of the Higgs boson; these couplings have not been directly constrained previously. The polarisation-dependent coupling-strength scale factors are defined as the ratios of the measured polarisation-dependent coupling strengths to those predicted by the Standard Model, and are determined using rate and kinematic information to be aL=0.91-0.18+0.10(stat.)-0.17+0.09(syst.) and aT= 1.2 ± 0.4 (stat.)-0.3+0.2(syst.). These coupling strengths are translated into pseudo-observables, resulting in κVV=0.91-0.18+0.10(stat.)-0.17+0.09(syst.) and ϵVV=0.13-0.20+0.28 (stat.)-0.10+0.08(syst.). All results are consistent with the Standard Model predictions
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