Now showing items 1-20 of 31

  • Reinforcement and backpropagation training for an optical neural network using self-lensing effects 

    Cruz-Cabrera, A.A.; Yang, Mingtao; Cui, Guogi; Behrman, Elizabeth C.; Steck, James E.; Skinner, Steven R. (IEEE, 2000-11)
    The optical bench training of an optical feedforward neural network, developed by the authors, is presented. The network uses an optical nonlinear material for neuron processing and a trainable applied optical pattern as ...
  • Numerical simulations of pulsatile flow in an end-to-side anastomosis model 

    Shaik, Eleyas; Hoffmann, Klaus A.; Dietiker, JF. (Tech Science Press, 2007-03)
    A potential interaction between the local hemodynamics and the artery wall response has been suggested for vascular graft failure by intimal hyperplasia (IH). Among the various hemodynamic factors, wall shear stress has ...
  • A hybrid scheme for the numerical simulation of shock/discontinuity problems 

    Mahmoudnejad, Niloufar; Hoffmann, Klaus A. (Taylor & Francis, 2011)
    To address accuracy issues for direct numerical simulation, a hybrid scheme based on the weighted compact scheme (WCS) and weighted essentially non-oscillatory (WENO) scheme is developed. The new hybrid method incorporates ...
  • Target tracking strategies for a nonlinear, flexible aircraft-inspired model 

    Chakravarthy, Animesh; Evans, Katie A.; Evers, Johnny; Kuhn, Lisa M. (IEEE, 2011-06-29)
    Aeroelastic wing micro aerial vehicle (MAV) concepts are being explored for military and civilian applications. However, on the whole, the issues of control of MAVs are largely unexplored. The authors seek to employ ...
  • Single Network Adaptive Critic aided nonlinear dynamic inversion for suboptimal command tracking 

    Lakshmikanth, Geethalakshmi S.; Padhi, Radhakant; Watkins, John Michael; Steck, James E. (IEEE, 2011-09-28)
    Using the Approximate Dynamic Programming (ADP) approach, nonlinear optimal control problems can be solved by using a dual neural network architecture called the Adaptive Critic (AC). A Single Network Adaptive Critic (SNAC) ...
  • Collision cones for quadric surfaces 

    Chakravarthy, Animesh; Ghose, Debasish (IEEE, 2011-12)
    The problem of collision prediction in dynamic environments appears in several diverse fields, which include robotics, air vehicles, underwater vehicles, and computer animation. In this paper, collision prediction of objects ...
  • Study of mobile mixed sensing networks in an automotive context 

    Chakravarthy, Animesh; Song, Kyungyeol; Peraire, Jaime; Feron, Eric (Springer, 2012)
    Mixed sensing mobile networks comprise of mobile sensors that have different sensing capabilities. We look at such sensor networks in an automotive context; wherein automobiles with two levels of sensing (and consequently ...
  • Numerical simulation of wall-pressure fluctuations due to a turbulent boundary layer 

    Mahmoudnejad, Niloufar; Hoffmann, Klaus A. (AMER INST AERONAUT ASTRONAUT, 2012)
    In this investigation, wall-pressure fluctuations due to a turbulent boundary layer are estimated by various numerical methods. Four different turbulence models, including one- and two-equation models and a recently developed ...
  • Generalization of the collision cone approach for motion safety in 3-D environments 

    Chakravarthy, Animesh; Ghose, Debasish (Springer, 2012-02)
    Avoidance of collision between moving objects in a 3-D environment is fundamental to the problem of planning safe trajectories in dynamic environments. This problem appears in several diverse fields including robotics, air ...
  • Adhesive-bonded composite joint analysis with delaminated surface ply using strain-energy release rate 

    Chadegani, Alireza; Yang, Chihdar; Smeltzer, Stanley S., III (AMER INST AERONAUT ASTRONAUT, 2012-03)
    This paper presents an analytical model to determine the strain energy release rate due to an interlaminar crack of the surface ply in adhesively bonded composite joints subjected to axial tension. Single-lap shear-joint ...
  • Effect of dents on crack growth in aluminum alloy under constant-amplitude loading 

    Smith, Bert; Shivally, Praveen; Kumar, Brijesh (AMER INST AERONAUT ASTRONAUT, 2012-03)
    The purpose of this study was to determine the effect of dents on the stable crack growth in 0.04-in.-thick 2024-T3 bare aluminum sheet. The test specimens were either pristine, dented, or reworked. The edge-cracked ...
  • Time-varying dynamics of a micro air vehicle with variable-sweep morphing 

    Chakravarthy, Animesh; Grant, Daniel T.; Lind, Rick (The American Institute of Aeronautics and Astronautics, 2012-05)
    In this paper, the longitudinal dynamics of a fast-morphing, variable-wing-sweep micro air vehicle are investigated from a flight dynamics perspective. The time scales over which the morphing occurs are of the same order ...
  • Dynamics and performance of tailless micro aerial vehicle with flexible articulated wings 

    Paranjape, Aditya A.; Chung, Soon-Jo; Hilton, Harry H.; Chakravarthy, Animesh (The American Institute of Aeronautics and Astronautics, 2012-05-05)
    The purpose of this paper is to analyze and discuss the performance and stability of a tailless micro aerial vehicle with flexible articulated wings. The dihedral angles can be varied symmetrically on both wings to control ...
  • Numerical Analysis of Effects of Leading-Edge Protuberances on Aircraft Wing Performance 

    Malipeddi, Anil Kumar; Mahmoudnejad, Niloufar; Hoffmann, Klaus A. (American Institute of Aeronautics and Astronautics, 2012-09)
    The effects of biologically inspired leading-edge protuberances on aircraft wings were investigated by using a numerical scheme. Simulations were performed at a Reynolds number of 5.7 x 10(5) on wings with leading-edge ...
  • Crack propagation analysis using acoustic emission sensors for structural health monitoring systems 

    Kral, Zachary Tyler; Horn, Walter J.; Steck, James E. (Hindawi Publishing Corporation, 2013)
    Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors ...
  • Multiqubit entanglement of a general input state 

    Behrman, Elizabeth C.; Steck, James E. (Rinton Press, Inc., 2013-01)
    Measurement of entanglement remains an important problem for quantum information. We present the design and simulation of an experimental method for an entanglement indicator for a general multiqubit state. The system can ...
  • Minimizing errors from linear and nonlinear weights of WENO scheme for broadband applications with shock waves 

    Arshed, Ghulam Murshed; Hoffmann, Klaus A. (Elsevier, 2013-03-29)
    Improvements in the numerical algorithm for the dynamics of flows that involve discontinuities and broadband fluctuations simultaneously are proposed. These two flow features suggest numerical strategies of a paradoxical ...
  • A quantum neural network computes its own relative phase 

    Behrman, Elizabeth C.; Steck, James E. (IEEE, 2013-04-17)
    Complete characterization of the state of a quantum system made up of subsystems requires determination of relative phase, because of interference effects between the subsystems. For a system of qubits used as a quantum ...
  • Detached eddy investigation of cavity resonance phenomenon in slender cavities 

    Syed, Shoeb Ahmed; Hoffmann, Klaus A. (AMER INST AERONAUTICS ASTRONAUTICS, 2013-05)
    Aerodynamic noise generation due to the presence of surface discontinuity has been a topic of research for more than five decades. Most investigations carried out are on cavities ranging from small gaps to large cavities ...
  • Modified state observer based adaptation of a general aviation aircraft - simulation and flight test 

    Pappu, Venkatasubramani S. R.; Steck, James E.; Rajagopal, Karthikeyan; Balakrishnan, S. N. (American Institute for Aeronautics and Astronautics, 2014-01)
    This paper presents some issues encountered while flight testing a Model Reference Adaptive dynamic inverse controller (MRAC), on a General Aviation (GA) fly-by-wire test bed. Adaptation was replaced with a Modified ...