2022

• S. Kadam, K. S. Phogat, R. N. Banavar, D. Chatterjee, “Exact isoholonomic motion of the planar Purcell's swimmer”, IEEE Transactions on Automatic Control, Vol. 67(1), pp. 429-​435, 2022. A. Nayak, R. Banavar, D. H. S. Maithripala, “Stabilizing a spherical pendulum on a quadrotor”, Asian Journal of Control, Vol. 24(3), pp. 1112-1121, 2022.
• S. Das, N. Khaneja, “Composite pulse combinations for chirp excitation”, Journal of Magnetic Resonance, 347, 107359, 2022.
• S. Das, J. Jacob, N. Khaneja, “Mechanism of chirp excitation”, Journal of Magnetic Resonance Open, Volumes 10-11, 100026, 2022.
• S. Das, A. Aravind, A. Cherukuri, D. Chatterjee, “Near-optimal solutions of convex semi-infinite programs via targeted sampling”, Annals of Operations Research, Vol. 318, pp. 129—​146, 2022.
M. R. Sheriff, D. Chatterjee, “Novel min-max reformulations of linear inverse problems”, Journal of Machine Learning Research, Vol. 23, Paper No. 28, pp. 1—​46, 2022.
• Y. Kumar, S. Srikant, D. Chatterjee, M. Nagahara, “Sparse optimal control problems with intermediate constraints: necessary conditions”, Optimal Control, Applications and Methods, Vol. 43, No. 2, pp. 369—​385, 2022.
• A. A. Joshi, D. Chatterjee, R. Banavar, “Robust discrete-time Pontryagin maximum principle on matrix Lie groups”, IEEE Transactions on Automatic Control, Vol. 67, No. 7, pp. 3545—​3552, 2022.
T. Ikeda, M. Nagahara, D. Chatterjee, S. Srikant, “Constrained smoothing splines by optimal control”, IEEE Control Systems Letters, Vol. 6, pp. 1298—​1303, 2022.
• M. Bhatt, S. Srikant, A. K. Sanyal, “Discrete-time rigid body pose estimation based on lagrange–d’alembert principle”, Journal of Nonlinear Science, vol. 32, no. 6, pp. 1–23, 2022.
• M. Dutta, E. Panteley, A. Loria, S. Srikant, “Strict Lyapunov functions for dynamic consensus in linear systems interconnected over directed graphs”, IEEE Control Systems Letters, vol. 6, pp. 2323–2328, 2022.
• R. Deori, A. A. Kulkarni, “Information revelation through signalling”, Systems & Control Letters, Vol. 169, 2022.
• K. N. Chadha, A. A. Kulkarni, “On independent cliques and linear complementarity problems”, Indian J Pure Appl Math, Vol. 53, pp. 1036-1057, 2022.
• P. V. Patil, L. Vachhani, S. Ravitharan, S. Chauhan, “Sequential state and unknown parameter estimation strategy and its application to a sensor fusion problem”, IEEE Sensors, vol. 22, no. 21, pp. 20665-20675, 2022.
• P. Patil, L. Vachhani, S. Ravitharan, S. Chauhan, “Robust state and unknown input estimator and its application to robot localization”, IEEE/ASME Transaction on Mechatronics, vol. 27, no. 6, pp. 5147-5158, 2022.
• S. Nema, L. Vachhani, “Surgical instrument detection and tracking technologies: Automating dataset labeling for surgical skill assessment”, Frontiers in Robotics and AI, vol. 9, 2022.
• M. Jena, L. Vachhani, A. Sinha, “A Deep Reinforcement Learning Approach for Multi-Agent Mobile Robot Patrolling”, International Journal of Intelligent Robotics and Applications, Springer, vol. 6, 724-745, 2022.
• S. Suvarna, H. Chung, A. Sinha, R. S. Pant, “Revised semi-empirical aerodynamic estimation for modelling flight dynamics of an airship”, Aerospace Science and Technology, Vol. 126, 2022.
• R. Singh, A. Maity, P. S. V. Nataraj, “Dynamic modeling and robust nonlinear control of a laboratory gas turbine engine”, Aerospace Science and Technology, vol. 126, 2022.
• D. D. Gawali, A. Zidna, P. S. V. Nataraj, “An Integrative Approach for Analysis of Nonlinear Electrical Circuits Using-Polynomial B-Spline Expansion and B-Spline Krawczyk Operator”, International Journal of Applied and Computational Mathematics, vol. 8, 2022.
• R. Singh, P. S. V. Nataraj, A. Maity, “Nonlinear Control of a Gas Turbine Engine with Reinforcement Learning”, Lecture Notes in Networks and Systems, vol. 359, pp. 105 - 120, 2022.

2021

• A. A. Joshi, D. H. S. Maithripala, R. N. Banavar, “A bundle framework for observer design on smooth manifolds with symmetry”, Journal of Geometric Mechanics, Vol. 13 (2), pp. 247-271, 2021.
N. Raj, R. N. Banavar, Abhishek, M. Kothari, “Robust Attitude Tracking for Aerobatic Helicopters: A Geometric Approach”, IEEE Transactions on Control Systems Technology, vol. 29, no. 1, pp. 150-164, Jan. 2021.
• S. Sarkar, R. Purusottam, A. Kumar, N. Khaneja, “Chirp pulse sequences for broadband pi-rotation”, Journal of Magnetic Resonance 328, 107002, 2021.
• C. Maheshwari, S. Srikant, D. Chatterjee, “Stabilization under round-robin scheduling of control inputs in nonlinear systems”, Automatica, Vol. 134, 2021.
• P. Dey, N. Balachandran, D. Chatterjee, “Complexity of constrained sensor placement problems for optimal observability”, Automatica, Vol. 131, 2021.
• M. Assif, M. R. Sheriff, D. Chatterjee, “Measure of quality of finite-dimensional linear systems: a frame-theoretic view”, Systems & Control Letters, Vol.151, 2021.
• P. K. Mishra, S. Diwale, C. Jones, D. Chatterjee, “Reference tracking stochastic model predictive control over unreliable channels and bounded control actions”, Automatica, Vol. 127, 2021.
• C. Maheshwari, S. Srikant, D. Chatterjee, “Optimal multiplexing of discrete time constrained control systems on matrix Lie groups”, IEEE Transactions on Automatic Control, Vol. 66, No. 4, pp. 1895—​1901, 2021.
• R. A. Razak, S. Srikant, H. Chung, “Scalar field estimation with mobile sensor networks”, International Journal of Robust and Nonlinear Control, vol. 31, no. 9, pp. 4287–4305, 2021.
• V. K. Singh, V. Natarajan, “Finite-dimensional controllers for consensus in a leader-follower network of marginally unstable infinite-dimensional agents”, IEEE Control Systems Letters, vol. 6, pp. 590-595, 2021 (accepted for presentation at CDC 2021).
• V. Natarajan, “Compensating PDE actuator and sensor dynamics using Sylvester equation”, Automatica, 123, 2021.
• A. Vora, A. A. Kulkarni, “Minimax Theorems for Finite Blocklength Lossy Joint Source-Channel Coding over an Arbitrarily Varying Channel”, Probl Inf Transm, Vol. 57, pp. 99-128, 2021.
• K. N. Chadha, A. A. Kulkarni, J. Nair, “Efficiency Fairness Tradeoff in Battery Sharing”, Operations Research Letters, Vol. 49(3), pp. 377-384, 2021.
• V. Deulkar, J. Nair, A. A. Kulkarni, “Statistical Economies of Scale in Battery Sharing”, Journal of Energy Storage, Vol. 33, 2021.
• S. C. Nagavarapu, L. Vachhani, A. Sinha, S. Buruily, “Generalizing Multi-agent Graph Exploration Techniques”, International Journal of Control, Automation and Systems, vol. 19, pp. 491-504, 2021.
• S. C. Nagavarapu, L. Vachhani, A. Sinha, S. Buriuly, “Generalizing Multi-agent Graph Exploration Techniques”, International Journal of Control, Automation, and Systems, vol. 19, no. 1, pp.491-504, 2021.
• D. D. Gawali, B. V. Patil, A. Zidna, P. S. V. Nataraj, “Constrained global optimization of multivariate polynomials using polynomial B-spline form and B-spline consistency prune approach”, RAIRO - Operations Research, vol. 55, pp. 3743 - 3771, 2021.
• P. U. Sunil, J. Barve, P. S. V. Nataraj, “Boiler controls and operation from the perspective of renewable energy integration to electrical grid”, Design, Analysis and Applications of Renewable Energy Systems, pp. 1 - 21, 2021.

2020

• A. K. Pal, S. Kamal, X. Yu, S. K. Nagar, B. Bandyopadhyay, “Free-will arbitrary time terminal sliding mode control”, IEEE Transactions on Circuits and Systems II: Express Briefs, Oct. 2020. doi: 10.1109/TCSII.2020.3028175.
• A. K. Pal, S. Kamal, S. K. Nagar, B. Bandyopadhyay, L. Fridman, “Design of controllers with arbitrary convergence time”, Automatica, Vol.112, 2020.
• A. K. Pal, S. Kamal, S. K. Nagar, B. Bandyopadhyay, L. Fridman, “ Authors’ Reply To:(CI 20-0229) Comments on Design of controllers with arbitrary convergence time [Automatica 108710]”, Automatica 122, p.109194, 2020.
• K. Kumari, B. Bandyopadhyay, J. Reger, A.K. Behera, “Event-triggered sliding mode control for a high-order system via reduced-order model based design”, Automatica 121, p.109163, 2020.
• M. Bhandari, D. Fulwani, B. Bandopadhyay, R. Gupta, “Reduced-order event-triggered controller for a singularly perturbed system: An active suspension case”, IET Control Theory & Applications, vol. 14, pp. 2703 - 2713, 2020.
• D. Khimani, M. Patil, B. Bandyopadhyay, A. K. Behera, “ Reduced‐order sliding function design for a class of nonlinear systems”, Asian Journal of Control, Vol. 22(4), pp.1437-1446, 2020.
• P. S. Babu, N. Xavier, B. Bandyopadhyay, “Robust output regulation for state feedback descriptor systems with nonovershooting behaviour”, European Journal of Control, Vol 52, pp. 19-25, March, 2020.
• S. Kamal, P. R. Kumar, A. Chalanga, J. K. Goyal, B. Bandyopadhyay, L. Fridman, “A New Class of Uniform Continuous Higher-Order Sliding Mode Controllers”, , Vol. 142(1), p. 011005, 2020.
• N. Raj, R. Banavar, Abhishek, M. Kothari, “Attitude Control of a Novel Tailsitter: Swiveling Biplane-Quadrotor”, AIAA Journal of Guidance, Control and Dynamics, Vol. 43(3), pp. 599-607, 2020.
• P. Paruchuri, S. Kotpalliwar, K. S. Phogat, D. Chatterjee, R. Banavar, “A frequency-constrained geometric Pontryagin maximum principle on matrix Lie groups”, Int J Robust Nonlinear Control, Vol. 30(15), pp. 6281-6297, 2020.
• M. Assif, D. Chatterjee, R. Banavar, “A simple proof of the discrete time geometric Pontryagin maximum principle on smooth manifolds”, Automatica, Vol. 114, 2020.
N. Khaneja, "Time Optimal Control of Coupled Spin Dynamics: A global analysis”, Automatica 111, 108639, 2020.
• K. Albert, K. S. Phogat, F. Anhalt, R. Banavar, D. Chatterjee, B. Lohmann, “Structure-preserving constrained optimal trajectory planning of a wheeled inverted pendulum”, IEEE Transactions on Robotics, Vol. 36, No. 3, pp. 910—​923, 2020.
• M. R. Sheriff, D. Chatterjee, “A complete characterization of optimal dictionaries for least squares representation”, Linear Algebra and Its Applications, Vol. 601, pp. 219—​264, 2020.
• P. K. Mishra, D. Chatterjee, D. Quevedo, “Stochastic predictive control under intermittent observations and unreliable actions”, Automatica, Vol. 118, 2020.
• M. Assif, D. Chatterjee, R. Banavar, “Scenario approach for minmax optimization in the nonconvex setting: positive results and caveats”, SIAM Journal of Optimization, Vol. 30, No. 2, pp. 1119—​1143, 2020.
• A. Kundu, D. Chatterjee, “Robust matrix commutator conditions for stability of switched linear systems under restricted switching”, Automatica, Vol. 115, 2020.
• M. Nagahara, D. Chatterjee, N. Challapalli, M. Vidyasagar, “CLOT norm minimization for continuous-time hands-off control”, Automatica, Vol. 113, 2020.
• V. K. Singh, V. Natarajan, “Reduced-order controllers for multi-agent consensus using output regulation viewpoint,” Automatica, 119, 2020.
• A. A. Kulkarni, I. Yadav, A. Karandikar, “Strategy-Proof Spectrum Allocation among Multiple Operators in Wireless Networks”, IEEE Transactions on Vehicular Technology, Vol. 69, pp. 15964 - 15977, 2020.
• M. Abraham, A. A. Kulkarni, “Price-coupling Games and the Generation Expansion Planning Problem”, Annals of Operations Research, vol. 295, pp. 1-19, 2020.
• V. Deulkar, J. Nair, A. A. Kulkarni, “Sizing Storage for Reliable Renewable Integration: A Large Deviations Approach”, Journal of Energy Storage, Vol. 30, 2020.
• K. N. Chadha, A. A. Kulkarni, “Aggregate Play and Welfare in Strategic Interactions on Networks”, Journal of Mathematical Economics, vol. 88, pp. 72-86, 2020.
• S. T. Jose, A. A. Kulkarni, “Shannon meets von Neumann: A Minimax Theorem for Channel Coding in the Presence of a Jammer”, IEEE Transactions on Information Theory, vol. 66, pp. 72-86, 2842-2859, 2020.
• G. K. Arunkumar, L. Vachhani, “3-D Acoustic Homing using 2-D Asymptotes”, Mechatronics, vol. 70, 2020.
• P. Vyas, L. Vachhani, K. Sridharan, “Interval Analysis Technique for Versatile and Parallel Multi-Agent Collision Detection and Avoidance”, Journal of Intelligent Robotic Systems, vol. 98, pp. 705-720, 2020.
• A. V. Borkar, A. Sinha, L. Vachhani, H. Arya, “Application of Lissajous curves in trajectory planning of multiple agents”, Autonomous Robots, vol. 44, pp. 233-250, 2020.
• A. V. Borkar, S. Hangal, H. Arya, A. Sinha, L. Vachhani, “Reconfigurable formations of quadrotors on Lissajous curves for surveillance applications”, European Journal of Control, Vol. 56, pp. 274-288, 2020.
• L. Vachhani, “CORDIC as a switched nonlinear system”, Circuits, Systems and Signal Processing, vol 39, pp. 3234-3249, 2020.
• P. S. Dhabe , P. S. V. Nataraj, “A GPU parallel Bernstein algorithm for polynomial global optimization”, International Journal of Systems Assurance Engineering and Management, vol. 11, pp. 21-44, 2020.
• S. Mate, H. Kodamana, S. Bhartiya, P. S. V. Nataraj, “A Stabilizing Sub-Optimal Model Predictive Control For Quasi-Linear Parameter Varying Systems”, IEEE Control Systems Letters, vol. 4, pp. 402-407, 2020.
• D. D. Gawali, B. V. Patil, A. Zidna, P. S. V. Nataraj, “A B-Spline Global Optimization Algorithm for Optimal Power Flow Problem Advances in Intelligent Systems and Computing”, vol. 991, pp. 58-67, 2020.
• P. U. Sunil, K. Desai, J. Barve, P. S. V. Nataraj, “An experimental case study of robust cascade two-element control of boiler drum level”, ISA Transactions, vol. 96, pp. 337-351, 2020.

2019

A. K. Paul, B. Bandyopadhyay, “Multifunctional Arc-Welding Controller Using SOSMC Technique”, IEEE Transactions on Control Systems Technology, vol. 27, pp. 2245-2253, 2019.
K. Kumari, B. Bandyopadhyay, K. S. Kim, H. Shim, “Output feedback based event-triggered sliding mode control for delta operator systems,” Automatica, vol. 103, pp. 1-10, 2019.
A. Chalanga, M. Patil, B. Bandyopadhyay, H. Arya, “Output regulation using new sliding surface with an implementation on inverted pendulum system,” European Journal of Control, vol. 45, pp. 85-91, 2019.
M. Thomas, B. Bandyopadhyay, L. Vachhani, “Finite‐time posture stabilization of the unicycle mobile robot using only position information: A discrete‐time sliding mode approach”, International Journal of Robust and Nonlinear Control, vol. 29, pp. 1990-2006, 2019.
N. Xavier, P. S. Babu, B. Bandyopadhyay, R. Schmid, “Robust non-overshooting tracking control for fractional order systems”, International Journal of Robust and Nonlinear Control, Vol. 29 (12), pp. 3841-3858, 2019.
S. Kotpalliwar, P. Paruchuri, D. Chatterjee, R. Banavar, “Discrete time optimal control with frequency constraints for non-smooth systems”, Automatica, Vol. 107, pp. 493-501, 2019.
T. Kotwal, R. Gerard, R. Banavar, “An energy and dynamical systems perspective to the damping-induced self recovery phenomenon”, ASME Journal of Dynamical Systems, Measurement and Control, vol. 141, 2019.
A. Nayak, R. Banavar, “On Almost-Global Tracking for a Certain Class of Simple Mechanical Systems”, IEEE Transactions on Automatic Control, vol. 64(1), pp. 412-419, 2019.
N. Khaneja, “Double swept band selective excitation”, Global Journal of researches in Engineering:F Vol 19, Issue 2, 2019.
Y. Kumar, S. Srikant, D. Chatterjee, “Optimal sparse multiplexing of linear control systems”, Automatica, Vol. 106, pp. 134—​142, 2019.
P. Paruchuri, D. Chatterjee, “A discrete time Pontryagin maximum principle under state-action-frequency constraints”, IEEE Transactions on Automatic Control, Vol. 64, No. 10, pp. 4202-​4208, 2019.
N. Balachandran, A. Kundu, D. Chatterjee, “A randomized algorithm for stabilizing switching signals”, Mathematical Control and Related Fields, Vol. 9, No. 1, pp. 159—​174, 2019.
V. Natarajan, H.-C. Zhou, G. Weiss, E. Fridman, “Exact controllability of a class of nonlinear distributed parameter systems using back and forth iterations,” Int. J. Control, 92, pp. 145-162, 2019.
V. Natarajan, G. Weiss, “Minimal order controllers for output regulation of nonlinear systems,” IFAC J. Systems and Control , 7, pp. 1-15, 2019.
O. Angatkina, V. Natarajan, Z. Chen, M. Ding, J. Bentsman, “Modeling and control of resonance effects in steel casting mold oscillators,” Acta Mechanica , 230, pp. 2087-2104, 2019.
A. A. Kulkarni, “Near-Optimality of Linear Strategies for Static Teams with `Big' Non-Gaussian Noise”, IEEE Transactions on Automatic Control, Vol. 65, pp. 534-545, 2019.
M. Abraham, A. A. Kulkarni, “New Results on the Existence of Open Loop Nash Equilibria in Discrete Time Dynamic Games via Generalized Nash Games”, Mathematical Methods of Operations Research, vol. 89, pp. 157–172, 2019.
P. Vyas, L. Vachhani, K. Sridharan, “Hardware-efficient interval analysis based collision detection and avoidance for mobile robots”, Mechatronics, vol. 62, 2019.
V. Dwaracherla, S. Thakar, L. Vachhani, A. Gupta, A. Yadav, A. Modi, “Motion planning for point-to-point navigation of spherical robot using position feedback”, IEEE/ASME Transactions on Mechatronics, vol. 24(5), pp. 2416-2426, 2019.
S. Gupta, S. P. Duttagupta, L. Vachhani, M. Mitra, “Attitude control of LTA platform for generation of a non-oscillatory solar power”, Sol Energy, vol. 189, pp. 131-150, 2019.
D. Shah, L. Vachhani, “Swarm Aggregation without Communication and Global Positioning”, IEEE Robotics and Automation Letters, Vol. 4, pp. 886-893, 2019.
J. M. Monsingh, A. Sinha, “Trochoidal patterns generation using generalized consensus strategy for single-integrator kinematic agents” European Journal of Control, Vol. 47, pp. 84-92, 2019.
A. V. Borkar, V. S. Borkar, A. Sinha “Aerial monitoring of slow moving convoys using elliptical orbits”, European Journal of Control, Vol. 46, pp. 90-102, 2019.

2018

M. Patil, B. Bandyopadhyay, A. Chalanga, H. Arya, “Output Tracking of Non-minimum Phase Systems via Reduced Order Sliding Mode Design”, IEEE Transactions on Mechatronics, Vol. 23(4), pp. 1981-1992, 2018.
A. K. Behera, A. Chalanga, B. Bandyopadhyay, “A new geometric proof of super-twisting control with actuator saturation”, Automatica, vol. 87, pp. 437-441, Jan. 2018.
A. K. Behera, B. Bandyopadhyay, X. Yu, “Periodic event-triggered sliding mode control”, Automatica, , Vol.96, pp.61-72, 2018.
A. K. Behera, A. Chalanga, B. Bandyopadhyay, Corrigendum to “A new geometric proof of super-twisting control with actuator saturation” [Automatica 87 (2018) 437-441], Automatica, Vol. 96, pp. 398, Oct 2018.
N. Xavier, B. Bandyopadhyay, R. Schmid, “Robust Non-overshooting Tracking Using Continuous Control for Linear Multivariable Systems”, IET Control Theory and Applications, Vol.12, Issue 7, pp. 1006-1011, 2018.
K. Kumari, A. K. Behera, B. Bandyopadhyay, “Event-triggered sliding mode-based tracking control for uncertain Euler-Lagrange systems”, IET Control Theory and Applications, Vol.12, Issue 9, pp.1228-1235, 2018.
M. Thomas, S. Kamal, B. Bandyopadhyay, L. Vachhani, “Continuous higher order sliding mode control for a class of uncertain MIMO nonlinear systems: an ISS approach”, European Journal of Control, Vol.41, pp.1-7, 2018.
R. Guruganesh, B. Bandyopadhyay, H. Arya, G. K. Singh, “Design and Hardware Implementation of Autopilot Control Laws for MAV Using Super Twisting Control”, Journal of Intelligent & Robotic Systems, Vol. 90, pp.455-471, 2018.
P. S. Babu, N. Xavier, B. Bandyopadhyay, "Robust Nonovershooting Tracking Controller For Descriptor Systems", European Journal of Control, Vol 43, pp. 57-63, Sept 2018.
K. S. Phogat, D. Chatterjee, R. N. Banavar, “A discrete-time Pontryagin maximum principle on matrix Lie groups”, Automatica, Vol. 97, pp. 376-​391, 2018.
A. Nayak, R. N. Banavar, D. H. S. Maithripala, “Almost-global tracking for a rigid body with internal rotors”, European Journal of Control, Volume 42, 2018.
K. S. Phogat, D. Chatterjee, R. N. Banavar, “Discrete-time optimal attitude control of a spacecraft with momentum and control constraints”, AIAA Journal of Guidance, Control and Dynamics, Vol. 41, No. 1, pp. 199-211, 2018.
S. Kadam, R. Banavar, “Geometry of locomotion of the generalized Purcell’s swimmer: Modeling, controllability and motion primitives”, IFAC Journal of Systems and Control, Volume 4, 2018.
N. Khaneja, "Magnetic resonance with number states vs coherent states", International Journal of modern Physics B, 2018.
N. Khaneja, "Convexity, Majorization and Time Optimal Control of Coupled Spin Dynamics", Applied Modern Control Intech, Open (2018) https://cdn.intechopen
N. Khaneja, "Chirp Mixing", Chemical Physics Letters 704, 62-67, 2018.
N. Khaneja, "Electron dynamics in solid state via time varying wave vectors", Physica B 539, 29-34, 2018.
N. R. Chowdhury, S. Srikant, D. Chatterjee, “A new condition for asymptotic consensus over switching graphs”, Automatica, Vol. 97, pp. 18-​26, 2018.
P. K. Mishra, D. Chatterjee, D. Quevedo, “Stabilizing stochastic predictive control under Bernoulli dropouts”, IEEE Transactions on Automatic Control, Vol. 63, No. 6, pp. 1489-1500, 2018.
P. K. Mishra, D. Chatterjee, D. Quevedo, “Sparse and constrained stochastic predictive control for networked systems”, Automatica, Vol. 87, pp. 40-​51, 2018.
R. A. Razak, S. Srikant, H. Chung, “Decentralized and adaptive control of multiple nonholonomic robots for sensing coverage,” International Journal of Robust and Nonlinear Control, vol. 28, pp. 2636–2650, April 2018.
N. R. Chowdhury, S. Srikant, M. Maghenem, A. Loria, “On the estimation of the consensus rate of convergence in graphs with persistent interconnections”, International Journal of Control, vol. 91, no. 1, pp. 132–144, 2018.
V. Natarajan, G. Weiss, “Almost global asymptotic stability of a grid-connected synchronous generator,” Math. Control Signals Syst., 2018.
V. K. Singh, V. Natarajan, “On the existence of stable real nth-order transfer functions with desired phase at n frequencies,” IEEE Control System Letters, 2, pp. 695-700, 2018.
P. Pandit, A. A. Kulkarni, "A Linear Complementarity Based Characterization of the weighted independence number and the independent domination number in graphs", Discrete Applied Mathematics, Vol 244, pp 155--169, 2018.
P. Pandit, A. A. Kulkarni, "Refinement of the Equilibrium of Public Goods Games over Networks: Efficiency and Effort of Specialized Equilibria", The Journal of Mathematical Economics Vol 79, pp 125--139 2018.
M. Abraham, A. A. Kulkarni, "An ADMM-Based Algorithm for Solving DC-OPF in a Large Electricity Network Considering Transmission Losses", IET Generation, Transmission and Distribution, vol. 12, pp. 5811 – 5823, 2018.
S. T. Jose, A. A. Kulkarni, "Improved Finite Blocklength Converses for Slepian-Wolf Coding via Linear Programming", IEEE Transactions on Information Theory, vol. 65, pp. 2423 - 2441, 2018.
A. Harchowdhury, L. Kleeman, L. Vachhani, “Coordinated Nodding of a 2D Lidar for Dense 3D Range Measurements”, Joint publication in IEEE Robotics and Automation Letters, vol. 3, No. 4, pp 4108-4115, Oct. 2018.
G. K. Arunkumar, A. Sabnis, L. Vachhani, “Robust steering control for autonomous homing and its application in visual homing under practical conditions", Journal of Intelligent and Robotic Systems, Springer, Vol. 89 (3-4), pp 403-419, 2018.
T. Tripathy, A. Sinha, "Unicycle With Only Range Input: An Array of Patterns," IEEE Transactions on Automatic Control, vol. 63, no. 5, pp. 1300-1312, 2018.
P. U. Sunil, J. Barve, P. S. V. Nataraj, “A robust heat recovery steam generator drum level control for wide range operation flexibility considering renewable energy integration”, Energy, vol. 163, pp. 873-893, 2018.

2022

R. Seshan, R. Banavar, A. D. Mahindrakar, “Geometric Second-Order Laplacian Flow for Consensus on Lie Groups”, European Control Conference, July 15, 2022.
S. Ganguly, N. Randad, D. Chatterjee, R. Banavar, “Constrained trajectory synthesis via quasi-interpolation”, IEEE Conference on Decision & Control, December 2022.
M. Dutta, E. Panteley, A. Loria, S. Sukumar, “Strict Lyapunov functions for dynamic consensus in linear systems interconnected over directed graphs”, 61st IEEE Conference on Decision and Control (CDC), 2022.
B. Gurjar, S. Chattopadhyay, V. Natarajan, “Stabilization of a class of infinite-dimensional systems subjected to unknown matched disturbances,” 8th Indian Control Conference, Chennai, pp. 103-108, 2022.
V. K. Singh, A. Batra, V. Natarajan, “Output consensus in a heterogeneous leader-follower multi-agent system with input and communication delays,” 8th Indian Control Conference, Chennai, pp. 49-54, 2022.
B. P. Kumar, S. Chatterjee, V. Natarajan, “Stabilization of cascade interconnection of an 1D heat equation in polar coordinates and an ODE using LQR design,” 61st IEEE Conf. Decision and Control, Cancun, pp. 7264-7369, 2022.
M. K. Singh, A. A. Kulkarni, "Strategic Multiclass Classification with Non-uniform Preferences and its Relation to Incentive Compatibility", Indian Control Conference 2022
A. Singhal, A. Gupta, L. Vachhani, “Pendulum Actuated Spherical Robot: Dynamic Modeling Analysis for Wobble Precession", in proceedings of 22nd IFAC Symposium on Automatic Control in Aerospace (ACA 2022).
S. Buriuly, L. Vachhani, A. Sinha, S. Ravitharan, S. Chauhan, “Route planning for capacity restricted agents over railway network, without disrupting train schedules", in Proceedings of the IFAC International Conference on Advances in Control and Optimization of Dynamical Systems (ACODS), 2022.
T. Tripathy, A. Sinha, "Boundary surveillance using a unicycle: a limited information approach", AIAA SCITECH 2022 Forum, 2022.
A. Wakode, A. Sinha, "Online Evasive Strategy for Aerial Survey using Sierpinski curve", IFAC-PapersOnLine, Volume 55, Issue 22, 2022, Pages 129-134.
P. Shrivastava, T. Tripathy, A. Sinha, "Boundary Surveillance Using a Novel Target Switching Technique", IFAC-PapersOnLine, Volume 55, Issue 22, 2022, Pages 293-298.
A. Yesmin, K. Kumari, A. V. Borkar, A. Sinha, H. Arya, "Software-In-The-Loop validation of super twisting based sliding mode control for quadcopters", IFAC-PapersOnLine, Volume 55, Issue 22, 2022, Pages 123-128.
P. Dhabe , P. S. V. Nataraj, “A Modified Matrix Method for Efficient Computation of Bernstein Coefficients and its GPU Parallelization”, (2022) International Conference on Electrical, Computer, Communications and Mechatronics Engineering, ICECCME 2022.
R. Singh, A. Maity, B. Somani, P. S. V. Nataraj, “On-board Fault Diagnosis of a Laboratory Mini SR-30 Gas Turbine Engine”, (2022) IFAC-PapersOnLine, 55 (22), pp. 153 - 158
S. Nandy , R. Singh, A. Maity, P. S. V. Nataraj, “Robustification of Unscented Kalman Filtering to Identify Faults in Gas Turbine Engine”, (2022) IFAC-PapersOnLine, 55 (1), pp. 826 - 831

2021

S. Ganguly, S. Das, D. Chatterjee, R. Banavar, “Rate Constrained Discrete-time Maximum Principle”, IFAC PapersOnLine 54-19, pp. 346–351, 2021, Presented at the 7th IFAC Workshop on Lagrangian and Hamiltonian Methods in Nonlinear Control.
A. Jindal, R. Banavar, D. Chatterjee, “Feedback Linearization of Implicit Discrete Systems”, IFAC PapersOnLine 54-19, pp. 340-345, Presented at the 7th IFAC Workshop on Lagrangian and Hamiltonian Methods in Nonlinear Control.
Ikeda, M. Nagahara, D. Chatterjee, S. Srikant, “Constrained smoothing splines by optimal control”, 60th IEEE Conference on Decision and Control (CDC), 2021.
A. A. Paranjape, V. Natarajan, S. Ghosh, “Transient and asymptotic properties of robust adaptive controllers in the presence of non-coercive Lyapunov functions,” 60th IEEE Conf. Decision and Control, Austin, pp. 1161-1166, 2021.
A. S. Vora and A. A. Kulkarni, "Optimal Questionnaires for Screening of Strategic Agents", ICASSP 2021
J. V. Karthik, G. K. Arunkumar, M. Thomas, L. Vachhani, “Mobile Robot Navigation using State-Constrained Sliding Mode Control", in Proceedings of Indian Control Conference (ICC), IIT Bombay, India, Dec, 2021.
S. Nema, L. Vachhani, "Safe and Fast Path Planner for Minimally Invasive Surgery", in Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems 2021 (IROS'2021) Sept, 2021, Czech Republic.
D. Mallya, S. Kandala, L. Vachhani, A. Sinha, “Priority Patrolling using Multiple Agents", in Proceedings of the International Conference on Robotics and Automation (ICRA), 2021, Xi'an, China.
P. Thakkar, P. Patil, L. Vachhani, “Unobservable Spaces for Bearing-Only Localization", in Proceedings of the American Control Conference, 2021, New Orleans, USA.
T. Thakkar, A. Sinha, "Motion Planning for Tractor-Trailer System," 2021 Seventh Indian Control Conference (ICC), 2021, pp. 93-98.
S. Suvarna, H. Chung, A. Sinha, R. S. Pant, "Trajectory Planning using Nonlinear Receding Horizon Optimization for an Autonomous Airship”, 2021 Seventh Indian Control Conference (ICC), 2021, pp. 99-104.
P. Acharya, A. Sinha, A. Guha, “Conceptual Design of a Robotic Vehicle Refuelling System,” 2021 International Symposium of Asian Control Association on Intelligent Robotics and Industrial Automation (IRIA), 2021, pp. 388-393.
S. Sailo, K. Kumar, S. C. Patwardhan, P. S. V. Nataraj, “Development of non-cooperative distributed adaptive MPC schemes based on ARX models parameterized using orthonormal basis filters”, (2021) IFAC-PapersOnLine, 54 (3), pp. 257 - 262
R. Singh, S. Nandy, A. Maity, P. S. V. Nataraj, “Nonlinear Control of a Laboratory Gas Turbine Engine with Uncertain System Dynamics”, 2021 International Symposium of Asian Control Association on Intelligent Robotics and Industrial Automation, IRIA 2021, pp. 253 - 258

2020

L. Watermann, J. Reger, B. Bandyopadhyay, “Backstepping-Induced Terminal Sliding Mode Control with Strict Lyapunov Function”, IEEE Conference on Control Technology and Applications (CCTA), Montreal, QC, Canada, pp. 851-856, Aug., 2020.
K. Kumari, B. Bandyopadhyay, J. Reger, A. K. Behera, “Event-triggered Discrete-time Sliding Mode Control for High-order Systems via Reduced-order Model Approach”, IFAC-PapersOnLine, Vol. 53(2), pp. 6207-6212, 2020.
N. Raj, A. Simha, M. Kothari, A. Abhishek, R. Banavar, “Iterative Learning based feedforward control for Transition of a Biplane-Quadrotor Tailsitter”, UAS International Conference on Robotics and Automation (ICRA), 2020, Paris.
A. A. Joshi, D. Chatterjee, R. Banavar, “Robust discrete-time Pontryagin maximum principle on matrix Lie groups”, IEEE Conference on Decision & Control, December 2020.
Y. Kumar, S. Srikant, M. Nagahara, D. Chatterjee, D. E. Quevedo, “Maximum hands-off feedback control for finite-time stabilization”, 59th IEEE Conference on Decision and Control (CDC), 2020, pp. 3969-3974.
H. Oza, R. Banavar, S. Srikant, I. C. Morărescu, “Formation control using optimal time multiplexing”, 59th IEEE Conference on Decision and Control (CDC), 2020, pp. 4055-4059.
M. Bhatt, S. Sukumar, A. K. Sanyal, “Rigid Body Geometric Attitude Estimator using Multi-rate Sensors,” 59th IEEE Conference on Decision and Control (CDC), 2020, pp. 1511-1516.
E. Panteley, A. Loria, S. Sukumar, “Strict Lyapunov functions for consensus under directed connected graphs”, European Control Conference (ECC), 2020, pp. 935-940.
S. Chatterjee, V. Natarajan, “Steady-state to steady-state transfer of PDEs using semi-discretization and flatness”, 59th IEEE Conf. Decision and Control, Jeju Island, pp. 4454-4459, 2020.
P. Lorenzetti, G. Weiss, V. Natarajan, “Integral control of stable nonlinear systems based on singular perturbations”, 21st IFAC World Congress, Berlin, pp. 6157-6164, 2020.
A. S. Vora, A. A. Kulkarni, "Information Extraction from a Strategic Sender over a Noisy Channel", Proceedings of the IEEE Conference on Decision and Control, 2020.
A. S. Vora, A. A. Kulkarni, "Zero Error Strategic Communication, Proceedings of SPCOM 2020.
A. S. Vora, A. A. Kulkarni, "Achievable Rates for Strategic Communication", Proceedings of the International Symposium on Information Theory, 2020.
A. S. Vora, A. A. Kulkarni, "Communicating with a Strategic Sender", Proceedings of the National Conference on Communications 2020.
V. Yogi, L. Vachhani, “Commercial-Of The-Shelf (COTS) Solution for Robot Sensing and Control”, in Proceedings of Indian Control Conference (ICC), Jan 2020.
V. Kadam, L. Vachhani, A. Gupta, “Control of an Omnidirectional Mobile Base with Multiple Spherical Robots”, in Proceedings of Indian Control Conference (ICC), Jan 2020.
P. U. Sunil, K. Desai, J. Barve, P. S. V. Nataraj, “Experimental study and identification of linear model with parameter variation for drum type laboratory scale boiler”, (2020) IFAC-PapersOnLine, 53 (1), pp. 608-615.

2019

P. S. Babu, N. Xavier, B. Bandyopadhyay, “Integral Sliding Mode Control for Fractional Order Descriptor Systems”, 18th European Control Conference (ECC), Naples, Italy, pp. 3601-3605, June, 2019. 218.
K. Kumari, B. Bandyopadhyay, “Observer Based Event-Triggered Sliding Mode Control for Uncertain Chain of Integrators System”, 18th European Control Conference (ECC), Naples, Italy, pp. 2128-2133, June, 2019.
S. Nair, R. Banavar, “Discrete Optimal Control of Interconnected Mechanical Systems”, Proceedings of the NOLCOS 2019, Vienna, Austria, Sept. 3 - 5, 2019
S. Nair, R. Banavar, D. H. S. Maithripala, “Control Synthesis for an Underactuated Cable Suspended System Using Dynamic Decoupling”, Proceedings of the American Control Conference, June 2019.
J. Jacob, S. Das, N. Khaneja, "A Concise Method of Pole Placement to Stabilize the Linear Time Invariant MIMO System," 2019 Sixth Indian Control Conference (ICC), Hyderabad, India, 2019.
M. Nagahara, D. Chatterjee, “Necessary conditions for optimality for the CLOT norm optimal control problem”, Indian Control Conference, December 2019.
M. Kishida, M. Nagahara, D. Chatterjee, “Discrete-time maximum hands-off control with minimum switches”, IEEE Conference on Decision & Control, Nice, December 2019.
A. Tanwani, D. Chatterjee, L. Gruene, “Performance bounds for stochastic receding horizon control with randomly sampled measurements”, IEEE Conference on Decision & Control, Nice, December 2019.
M. Goyal, N. Karamchandani, D. Chatterjee, D. Manjunath, “Maintaining ferment”, IEEE Conference on Decision & Control, Nice, December 2019.
R. A. Razak, S. Srikant, H. Chung, “Estimating Scalar Fields with Mobile Sensor Networks”, 6th Indian Control Conference (ICC), Dec 18-20, 2019, Hyderabad, India – winner Best Student Paper Award.
P. Sankhe, S. Azim, S. Goyal, T. Choudhary, K. Appaiah, S. Srikant, “Indoor Distance Estimation using LSTMs over WLAN Network”, 16th Workshop on Positioning, Navigation and Communications (WPNC), 2019, pp. 1-6.
C. Maheshwari, S. Srikant, D. Chatterjee, “On round robin temporal scheduling of exponentially stabilizing controllers”, Asian Control Conference, June 9-12, 2019, Kitakyushu, Japan - Finalist for the Shimemura best student paper award.
K. Sridhar, S. Srikant, “Finite-Time, Event-Triggered Tracking Control of Quadrotors”, 5th CEAS Conference on Guidance, Navigation and Control, April 3-5, 2019, Milano, Italy.
K. C. Tejaswi, S. Srikant, “Backstepping Control for State Constrained Systems”, 5th CEAS Conference on Guidance, Navigation and Control, April 3-5, 2019, Milano, Italy.
H. Sinhmar, S. Srikant, “Distributed Model Independent Algorithm for Spacecraft Synchronization under Relative Measurement Bias”, 5th CEAS Conference on Guidance, Navigation and Control, April 3-5, 2019, Milano, Italy.
V. Natarajan, “Stabilization of PDE-ODE cascade systems using Sylvester equations”, 58th IEEE Conf. Decision and Control, Nice, pp. 5906-5911, 2019.
A. A. Kulkarni, A. Kowli, "Addressing the Free-Rider Problem in Voluntary Demand Response Programs", Indian Control Conference, 2019.
V. Deulkar, J. Nair, A. A. Kulkarni, "Sizing Storage for Reliable Renewable Integration", PowerTech 2019.
I. Yadav, A. A. Kulkarni, A. Karandikar, "Strategy-proof Spectrum Allocation among Multiple Operators", IEEE Wireless Communications and Networking Conference, 2019.
A. S. Vora, A. A. Kulkarni, "A Minimax Theorem for Finite Blocklength Joint Source-Channel Coding over an AVC", National Conference on Communications, 2019.
P. Thakkar, L. Vachhani, “Optimal Landmark Selection for Bearing-Only Navigation”, in Proceedings of Advances in Robotics (AIR19), 2019.
A. Vijaykumar, L. Vachhani, A. Gupta, “Real-time depth estimation using camera and IMU on the unstabilized platform of a spherical robot”, in Proceedings of Advances in Robotics (AIR19), 2019.
D. Shah, L. Vachhani, “Swarm Aggregation without Communication and Global Positioning”, in Proceedings of International Conference on Robotics and Automation (ICRA) 2019, Montreal, Canada.
G. K. Arunkumar, L. Vachhani, “Autonomous homing in 3D using partial state feedback on a novel sliding surface”, in Proceedings of European Control Conference 2019, June 2019, Naples, Italy.
A. Harchowdhury, L. Kleeman, L. Vachhani, “Simultaneous Obstacle Tracking and Shape Reconstruction of a Dynamic Obstacle using Sparse Depth Data", 3rd Cyber-Physical Systems Symposium (CyPhySS 2019), Indian Institute of Science, Bangalore.
S. Gupta, M. Mitra, L. Vachhani, S. Duttagupta, “Position Control of Solar Powered Aerostat for Reliable Power Generation in the Presence of Clouds”, in Proceedings of International Conference on Nascent Technologies in Engineering (ICNTE), January 2019.
A. Joshi, M. Bhatt, A. Sinha, “Modification of Hilbert's Space-Filling Curve to Avoid Obstacles: A Robotic Path-Planning Strategy”, Proceedings of Sixth Indian Control Conference (ICC), Hyderabad, India, Dec. 2019.
GR Mallik, A Sinha, “Regular convex polygon formation with deviated cyclic pursuit”, Proceedings of Fifth Indian Control Conference (ICC), Kanpur, India, Jan. 2019, pp. 107-112.
R. Singh, A. Maity, P. S. V. Nataraj, “Shaft speed control of laboratory gas turbine engine”, (2019) IFAC-PapersOnLine, 52 (12), pp. 262-267.

2018

N. Xavier, B. Bandyopadhyay, "Periodically Monotonic Tracking Using Intermittent Control With Multirate Output Feedback", IEEE International Conference on Industrial Technology (ICIT), Lyon, France, pp.274- 279, 2018.
P. S. Babu, B. Bandyopadhyay, "Integral Sliding Mode Based Composite Nonlinear Feedback Control For Descriptor Systems", 5th IFAC International Conference on Advances in Control and Optimization of Dynamical Systems, Hyderabad, India, pp.598- 603, 2018.
P. S. Babu, B. Bandyopadhyay, M. Thomas, “Robust Composite Non-linear Feedback Control For Descriptor Systems With General Reference Tracking”, In the Proceedings of 44th Annual Conference of IEEE Industrial Electronics Society, Washington D.C., USA, pp. 2434-2439, Oct. 2018.
M. Thomas, B. Bandyopadhyay, L. Vachhani, “A Finite-time Sliding Mode Observer for a Class of Perturbed Nonholonomic Systems”, In the Proceedings of 44th Annual Conference of IEEE Industrial Electronics Society, Washington D.C., USA, pp. 2165-2170, Oct. 2018.
N. Xavier, B. Bandyopadhyay, X. Yu, “Discrete Time Intermittent Sliding Mode Control with Multirate Output Feedback”, In the Proceedings of 44th Annual Conference of IEEE Industrial Electronics Society, Washington D.C., USA, pp. 2274-2279, Oct. 2018.
A. K. Behera, B. Bandyopadhyay, “On Stability of Event-Triggered Systems With Sliding Mode Control”, 15th International Workshop on Variable Structure Systems, Graz, Austria, pp. 427-431. July, 2018.
B. Tamhane, S. Kurode, B. Bandyopadhyay, “Novel Higher Order Sliding Mode Observer for Output Noise Attenuation”, 15th International Workshop on Variable Structure Systems, Graz, Austria, pp. 297-302. July, 2018.
A. Nayak, R. N. Banavar, “Almost-global tracking of the unactuated joint in a pendubot”, Proc. IFAC workshop on Lagrangian and Hamiltonian Methods in Nonlinear Control, Chile, May 2018.
K. S. Phogat, R. N. Banavar, D. Chatterjee, “Structure-preserving discrete-time optimal maneuvers of a wheeled inverted pendulum”, Proc. IFAC workshop on Lagrangian and Hamiltonian Methods in Nonlinear Control, Chile, May 2018.
S. Kadam, R. N. Banavar, “Modelling and controllability of a slender, flexible micro-swimmer using Cox theory”, Proc. 7th IEEE RAS/EMBS International Conference on Biomedical Robotics and Biomechatronics, Netherlands, 2018.
S. Kotpalliwar, P. Paruchuri, K.S. Phogat, D. Chatterjee, R. Banavar, “A frequency-constrained geometric Pontryagin maximum principle on matrix Lie groups”, Proc. IEEE, Conference on Decision and Control, Florida, USA, 2018.
M. Assif, R. Banavar, A. Bloch, M. Camarinha, L. Colombo, “Variational collision avoidance problems on Riemannian manifolds”, Proc. IEEE Conference on Decision and Control, Florida, USA, 2018.
M. Nagahara, D. Chatterjee, “Optimal control with sparsity constraints in the frequency domain”, SICE 2018, Nara, Japan.
P. Dey, N. Balachandran, D. Chatterjee, “On minimum cost sparsest input-connectivity for controllability of linear systems”, SICE 2018, Nara, Japan.
S. Srikant, E. Panteley, A. Loria, W. Pasillas, “On consensus of double integrators over directed graphs and with relative measurement bias”, 57th IEEE Conference in Decision and Control (CDC), Dec. 17–19, 2018.
R. A. Razak, S. Srikant, H. Chung, “Distributed Coverage Control of Mobile Sensors: Generalized Approach using Distance Functions”, 57th IEEE Conference in Decision and Control (CDC), Dec. 17–19, 2018.
Y. Kumar, S. Srikant, D. Chatterjee, “On Sparse Optimal Control Scheduling for Linear Systems”, SICE Annual Conference, September 11-14, 2018, Japan.
M. Sood, S. Moharir, A. A. Kulkarni, "Pricing and Commission in Two-Sided Markets with Free Upgrades", to appear in the Lecture Notes in Computer Science, 2018.
S. Theresa Jose, A. A. Kulkarni, "On a Game Between a Delay-constrained Communication System and a Finite State Jammer", accepted by IEEE Conference on Decision and Control, 2018.
M. Sood, A. A. Kulkarni, S. Moharir, "Platform Competition for Throughput in Two-sided Freelance Markets", Proceedings of SPCOM 2018.
S. T. Jose, A. A. Kulkarni, "New Finite Blocklength Converses for Asymmetric Multiple Access Channels via Linear Programming", Proceedings of SPCOM 2018.
M. Sood, S. Moharir, A. A. Kulkarni, "Pricing in Two-Sided Markets in the Presence of Free Upgrades", COMSNETS 2018.
M. Abraham, A. A. Kulkarni, "On the Existence of Equilibria in Price-Coupling Games", Proceedings of the Indian Control Conference, 2018.
A. Harchowdhury, L. Kleeman, L. Vachhani, “Coordinated Nodding of a 2D Lidar for Dense 3D Range Measurements”, in Proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems, Oct, 2018, Madrid, Spain.
A. Chauhan, P. Vyas, L. Vachhani, A. Maity, "Optimal path planning for a non-holonomic robot using interval analysis", In Proceedings of Indian Control Conference (ICC), Jan 2018.
J. Moses M, A. Sinha, H. Chung, “Geometric Pattern Formation with Coordinated Double-Integrator Agents”, 12th IFAC Symposium on Robot Control SYROCO 2018: Budapest, Hungary, 27–30 August 2018.
R. Singh, A. Maity, P. S. V. Nataraj, “Modeling, Simulation and Validation of Mini SR-30 Gas Turbine Engine”, (2018) IFAC-PapersOnLine, 51 (1), pp. 554-559.
H. Purohit, P. S. V. Nataraj, “Parallel algorithms for template and bound generation in robust control”, IEEE International Conference on Control and Automation, ICCA, 2018-June, pp. 1174-1179.
D. Makwana, P. S. V. Nataraj, “Automated Synthesis of Robust QFT-PID Controllers based on Piecewise Linear Approximations”, IEEE International Conference on Control and Automation, ICCA, 2018-June, pp. 787-793.