The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform

E.j. Holder - One of the best experts on this subject based on the ideXlab platform.

  • Sidelobe performance in quadratic phase conformal arrays
    IEEE Transactions on Antennas and Propagation, 1991
    Co-Authors: E.j. Holder
    Abstract:

    Sidelobe performance in an array with a quadratic phase distribution is related to the array curvature. Conditions are Derived that ensure well-behaved sidelobes for quadratic phase conformal arrays. A similar condition is Derived for parabolic shaped arrays and results are given to illustrate the validity of the Derived Requirement for well-behaved sidelobes for both parabolic and circular arrays. In addition, the sidelobe performance of a nonuniformly spaced linear array is related to the curvature of an equivalent conformal array.

Philip T. Krein - One of the best experts on this subject based on the ideXlab platform.

  • Singular Perturbation Theory for DC-DC Converters and Application to PFC Converters
    2007 IEEE Power Electronics Specialists Conference, 2007
    Co-Authors: Jonathan W. Kimball, Philip T. Krein
    Abstract:

    Many control schemes for dc-dc converters begin with the assertion that inductor currents are "fast" states and capacitor voltages are "slow" states. This assertion must be true for power factor correction (PFC) converters to allow independent control of current and voltage. In the present work, singular perturbation theory is applied to boost converters to provide rigorous justification of the time scale separation. Krylov-Bogoliubov-Mitropolsky (KBM) averaging is used to include switching ripple effects. A relationship between inductance, capacitance, load resistance, and loss resistances derives from an analysis of an approximate model. Similar results hold for buck and buck-boost converters. An experimental boost converter and a simulated PFC boost support the Derived Requirement.

Jonathan W. Kimball - One of the best experts on this subject based on the ideXlab platform.

  • Singular Perturbation Theory for DC-DC Converters and Application to PFC Converters
    2007 IEEE Power Electronics Specialists Conference, 2007
    Co-Authors: Jonathan W. Kimball, Philip T. Krein
    Abstract:

    Many control schemes for dc-dc converters begin with the assertion that inductor currents are "fast" states and capacitor voltages are "slow" states. This assertion must be true for power factor correction (PFC) converters to allow independent control of current and voltage. In the present work, singular perturbation theory is applied to boost converters to provide rigorous justification of the time scale separation. Krylov-Bogoliubov-Mitropolsky (KBM) averaging is used to include switching ripple effects. A relationship between inductance, capacitance, load resistance, and loss resistances derives from an analysis of an approximate model. Similar results hold for buck and buck-boost converters. An experimental boost converter and a simulated PFC boost support the Derived Requirement.

Lori A. Clarke - One of the best experts on this subject based on the ideXlab platform.

  • IHI - Process-based derivation of Requirements for medical devices
    Proceedings of the ACM international conference on Health informatics - IHI '10, 2010
    Co-Authors: Heather M. Conboy, George S. Avrunin, Lori A. Clarke
    Abstract:

    One goal of medical device certification is to show that a given medical device satisfies its Requirements. The Requirements that should be met by a device, however, depend on the medical processes in which the device is to be used. Such processes may be complex and, thus, critical Requirements may be specified inaccurately or incompletely, or even missed altogether. We are investigating a Requirement derivation approach that takes as input a model of the way the device is used in a particular medical process and a Requirement that should be satisfied by that process. This approach tries to produce a Derived Requirement for the medical device that is sufficient to prevent any violations of the process Requirement. Our approach combines a method for generating assumptions for assume-guarantee reasoning with one for interface synthesis to automate the derivation of the medical device Requirements. The proposed approach performs the Requirement derivation iteratively by employing a model checker and a learning algorithm. We implemented this approach and evaluated it by applying it to two small case studies. Our experiences showed that the proposed approach could be successfully applied to abstract models of portions of real-world medical processes and that the Derived Requirements of the medical devices appeared useful and understandable.

Hassan Reza - One of the best experts on this subject based on the ideXlab platform.

  • Deriving DO-178C Requirements Within the Appropriate Level of Hierarchy
    2012
    Co-Authors: Jamie P. White, Hassan Reza
    Abstract:

    In this paper, a set of criterion is proposed that assists an engineer in placing a Derived Requirement as defined by DO-178C in the proper document within the Requirement document hierarchy. The proper documentation of Derived Requirements has historically posed some issues when it comes to Requirements-based testing. For one thing, if the Derived Requirements are inappropriately documented, then it will be very difficult to establish traceability between individual Requirements to the elements of design, implementation, and verification. Consequently, the lack of correlation between elements of Requirements, design, code, and verification can jeopardize the safety of systems because it will be impossible to establish forward and backward traceability. To this end, the proposed criteria discussed in this work attempts to improve the visibility of Derived Requirements to prevent the unwanted consequences of masking required information from developers.