Model Reduction

My research addresses passivity preserving model reduction methods for systems describing interconnect in VLSI chips. I am investigating theoretical and implementation aspects  of a rational Krylov-type method, which guarantees passivity via interpolation at dominant spectral zeros. Currently, I am conducting a survey on RLCk circuit synthesis methods for converting reduced-order models to physical netlists, as part of an internship at TU/Eindhoven - NXP Semiconductors in Eindhoven, the Netherlands.

 Publications

  • R. Ionutiu, J. Rommes, A. Antoulas: "Passivity preserving model reduction using dominant spectral zero interpolation", accepted for publication in IEEE Transactions on COMPUTER-AIDED DESIGN of Integrated Circuits and System, 2008.
  • R. Ionutiu, S. Lefteriu, A. Antoulas: “Comparison of model reduction methods with applications to circuit simulation,” in Scientific Computing in Electrical Engineering SCEE 2006, ser. Mathematics in Industry, G. Ciuprina and D. Ioan, Eds. Berlin, Germany: Springer, 2007, vol. 11.
  • R. Ionutiu: “Model reduction for descriptor systems with applications to circuit simulation,” William Marsh Rice University, Houston, TX, Tech. Rep. TREE07-07, July 2007.  

Other Projects

  • "A survey of RLCk synthesis methods". Ivestigation of different methods for synthesizing reduced mathematical models into RLCk netlists, Marie Currie fellowship as part of the COMSON project Contract Number MRTN-CT-2005-019417 at TU/Eindhoven and NXP Semiconductors, Eindhoven, the Netherlands.
  • "Passivity preserving model reduction in the context of spectral zero interpolation" (MS thesis, June 2008). A new approach for passivity preserving model reduction was proposed, based on interpolation of dominant spectral zeros. The method guarantees stable and passive reduced models for linear circuits, irrespective of the underlying system formulation.
  • "Modeling and Control of Control Moment Gyroscope". Applicability and limitations of various control design methods were tested through the modeling and control of the control moment gyroscope (CMG), a device with applications in satellite attitude and spacecraft orientation control. CMG comes in different system configurations (linear and nonlinear), allowing for a comprehensive exploration of studied control procedures.
    MATLAB simulations were used to find the different control laws, which were then applied to the real system. Finally, comparisons between simulation and experimental results were investigated.
  • “Digital Logic Design: BCD adder”. Designed and tested a three-digit binary-coded-decimal (BCD) adder/subtractor. Project involved implementation using modern CAD techniques, programming in Verilog, testing with simulation and downloading to a FPGA board.
  • "BOS Intranet design". Bremen Online Services GmbH, Bremen, Germany. Developed a communication and information (Intranet) system for company internal use. Project involved programming in PHP and HTML and database management with mySQL.