Ram Iyer - Academia.edu (original) (raw)
Papers by Ram Iyer
SPIE Proceedings, 2003
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IEEE Transactions on Medical Imaging, 2017
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2016 American Control Conference (ACC), 2016
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Abstract. Implicit integration schemes for ODEs, such as Runge-Kutta and Runge-Kutta-Nyström met... more Abstract. Implicit integration schemes for ODEs, such as Runge-Kutta and Runge-Kutta-Nyström methods, are widely used in mathematics and engi-neering to numerically solve ordinary differential equations. Every integration method requires one to choose a step-size, h, for the integration. If h is too large or too small the efficiency of an implicit scheme is relatively low. As every implicit integration scheme has a global error inherent to the scheme, we choose the total number of computations in order to achieve a prescribed global error as a measure of efficiency of the integration scheme. In this paper, we propose the idea of choosing h by minimizing an efficiency function for general Runge-Kutta and Runge-Kutta-Nyström integration routines. This efficiency function is the critical component in making these methods variable step-size methods. We also investigate solving the intermediate stage values of these routines using both Newton’s method and Picard iteration. We then show...
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2006 American Control Conference, 2006
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Mathematical Modelling of Natural Phenomena, 2020
In this article, we consider the motion of a liquid surface between two parallel surfaces. Both s... more In this article, we consider the motion of a liquid surface between two parallel surfaces. Both surfaces are non-ideal, and hence, subject to contact angle hysteresis effect. Due to this effect, the angle of contact between a capillary surface and a solid surface takes values in a closed interval. Furthermore, the evolution of the contact angle as a function of the contact area exhibits hysteresis. We study the two-point boundary value problem in time whereby a liquid surface with one contact angle at t = 0 is deformed to another with a different contact angle at t = ∞ while the volume remains constant, with the goal of determining the energy loss due to viscosity. The fluid flow is modeled by the Navier-Stokes equations, while the Young-Laplace equation models the initial and final capillary surfaces. It is well-known even for ordinary differential equations that two-point boundary value problems may not have solutions. We show existence of classical solutions that are non-unique, ...
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International Journal of Applied Electromagnetics and Mechanics, 2008
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Journal of Physics: Conference Series, 2015
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Journal of Physics: Conference Series, 2016
ABSTRACT
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SPIE Proceedings, 2000
ABSTRACT
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2003 IEEE Aerospace Conference Proceedings (Cat. No.03TH8652)
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Ieee Control Systems, 2009
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Proceedings of the 2005, American Control Conference, 2005.
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Proceedings of the 37th IEEE Conference on Decision and Control (Cat. No.98CH36171)
Abstract We present a set of equations for a bulk ferromagnetic hysteresis model. We establish th... more Abstract We present a set of equations for a bulk ferromagnetic hysteresis model. We establish the connection between this set of equations and classical energy loss expressions for ferromagnetic hysteresis. We show analytically that for periodic inputs the ...
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Bookmarks Related papers MentionsView impact
ABSTRACT
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
SPIE Proceedings, 2003
Bookmarks Related papers MentionsView impact
IEEE Transactions on Medical Imaging, 2017
Bookmarks Related papers MentionsView impact
2016 American Control Conference (ACC), 2016
Bookmarks Related papers MentionsView impact
Abstract. Implicit integration schemes for ODEs, such as Runge-Kutta and Runge-Kutta-Nyström met... more Abstract. Implicit integration schemes for ODEs, such as Runge-Kutta and Runge-Kutta-Nyström methods, are widely used in mathematics and engi-neering to numerically solve ordinary differential equations. Every integration method requires one to choose a step-size, h, for the integration. If h is too large or too small the efficiency of an implicit scheme is relatively low. As every implicit integration scheme has a global error inherent to the scheme, we choose the total number of computations in order to achieve a prescribed global error as a measure of efficiency of the integration scheme. In this paper, we propose the idea of choosing h by minimizing an efficiency function for general Runge-Kutta and Runge-Kutta-Nyström integration routines. This efficiency function is the critical component in making these methods variable step-size methods. We also investigate solving the intermediate stage values of these routines using both Newton’s method and Picard iteration. We then show...
Bookmarks Related papers MentionsView impact
2006 American Control Conference, 2006
Bookmarks Related papers MentionsView impact
Mathematical Modelling of Natural Phenomena, 2020
In this article, we consider the motion of a liquid surface between two parallel surfaces. Both s... more In this article, we consider the motion of a liquid surface between two parallel surfaces. Both surfaces are non-ideal, and hence, subject to contact angle hysteresis effect. Due to this effect, the angle of contact between a capillary surface and a solid surface takes values in a closed interval. Furthermore, the evolution of the contact angle as a function of the contact area exhibits hysteresis. We study the two-point boundary value problem in time whereby a liquid surface with one contact angle at t = 0 is deformed to another with a different contact angle at t = ∞ while the volume remains constant, with the goal of determining the energy loss due to viscosity. The fluid flow is modeled by the Navier-Stokes equations, while the Young-Laplace equation models the initial and final capillary surfaces. It is well-known even for ordinary differential equations that two-point boundary value problems may not have solutions. We show existence of classical solutions that are non-unique, ...
Bookmarks Related papers MentionsView impact
International Journal of Applied Electromagnetics and Mechanics, 2008
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Journal of Physics: Conference Series, 2015
Bookmarks Related papers MentionsView impact
Journal of Physics: Conference Series, 2016
ABSTRACT
Bookmarks Related papers MentionsView impact
SPIE Proceedings, 2000
ABSTRACT
Bookmarks Related papers MentionsView impact
2003 IEEE Aerospace Conference Proceedings (Cat. No.03TH8652)
Bookmarks Related papers MentionsView impact
Ieee Control Systems, 2009
Bookmarks Related papers MentionsView impact
Proceedings of the 2005, American Control Conference, 2005.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Proceedings of the 37th IEEE Conference on Decision and Control (Cat. No.98CH36171)
Abstract We present a set of equations for a bulk ferromagnetic hysteresis model. We establish th... more Abstract We present a set of equations for a bulk ferromagnetic hysteresis model. We establish the connection between this set of equations and classical energy loss expressions for ferromagnetic hysteresis. We show analytically that for periodic inputs the ...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
ABSTRACT
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact