The Experts below are selected from a list of 226443 Experts worldwide ranked by ideXlab platform
Marco Pingaro - One of the best experts on this subject based on the ideXlab platform.
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An innovative H _ ∞ –norm based worst case Scenario approach for dynamic compliance optimization with applications to viscoelastic beams
Structural and Multidisciplinary Optimization, 2017Co-Authors: Paolo Venini, Marco PingaroAbstract:A novel frequency–based definition of dynamic compliance is introduced within the framework of H _ ∞ –norm based structural dynamics in the presence of load uncertainties. The system itself is supposed to depend on a vector of design parameters with respect to which an optimal design is pursued. A three-step Worst-Case-Scenario is then developed that finds the minimum-compliance structure capable of accounting for the entire norm–bounded load sets. Once the problem is initialized, the current worst load is found that is used as input to the minimization of the structural compliance and the procedure is repeated until convergence. Numerical examples are eventually proposed that deal with viscoelastic beams discretized via a truly–mixed finite–element scheme.
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An innovative Hź---norm based worst case Scenario approach for dynamic compliance optimization with applications to viscoelastic beams
Structural and Multidisciplinary Optimization, 2016Co-Authors: Paolo Venini, Marco PingaroAbstract:A novel frequency---based definition of dynamic compliance is introduced within the framework of Hź---norm based structural dynamics in the presence of load uncertainties. The system itself is supposed to depend on a vector of design parameters with respect to which an optimal design is pursued. A three-step Worst-Case-Scenario is then developed that finds the minimum-compliance structure capable of accounting for the entire norm---bounded load sets. Once the problem is initialized, the current worst load is found that is used as input to the minimization of the structural compliance and the procedure is repeated until convergence. Numerical examples are eventually proposed that deal with viscoelastic beams discretized via a truly---mixed finite---element scheme.
Paolo Venini - One of the best experts on this subject based on the ideXlab platform.
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An innovative H _ ∞ –norm based worst case Scenario approach for dynamic compliance optimization with applications to viscoelastic beams
Structural and Multidisciplinary Optimization, 2017Co-Authors: Paolo Venini, Marco PingaroAbstract:A novel frequency–based definition of dynamic compliance is introduced within the framework of H _ ∞ –norm based structural dynamics in the presence of load uncertainties. The system itself is supposed to depend on a vector of design parameters with respect to which an optimal design is pursued. A three-step Worst-Case-Scenario is then developed that finds the minimum-compliance structure capable of accounting for the entire norm–bounded load sets. Once the problem is initialized, the current worst load is found that is used as input to the minimization of the structural compliance and the procedure is repeated until convergence. Numerical examples are eventually proposed that deal with viscoelastic beams discretized via a truly–mixed finite–element scheme.
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An innovative Hź---norm based worst case Scenario approach for dynamic compliance optimization with applications to viscoelastic beams
Structural and Multidisciplinary Optimization, 2016Co-Authors: Paolo Venini, Marco PingaroAbstract:A novel frequency---based definition of dynamic compliance is introduced within the framework of Hź---norm based structural dynamics in the presence of load uncertainties. The system itself is supposed to depend on a vector of design parameters with respect to which an optimal design is pursued. A three-step Worst-Case-Scenario is then developed that finds the minimum-compliance structure capable of accounting for the entire norm---bounded load sets. Once the problem is initialized, the current worst load is found that is used as input to the minimization of the structural compliance and the procedure is repeated until convergence. Numerical examples are eventually proposed that deal with viscoelastic beams discretized via a truly---mixed finite---element scheme.
Jay Krishnan - One of the best experts on this subject based on the ideXlab platform.
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Articles Decontamination of a Worst-Case Scenario Class II Biosafety Cabinet Using Vaporous Hydrogen Peroxide
2012Co-Authors: Greg Fey, Stan Klassen, Steven Theriault, Jay KrishnanAbstract:The objective of this study was to evaluate both condensing (wet) and non-condensing (dry) vaporous hydrogen peroxide (VHP) technologies for decontaminating a Worst-Case Scenario Class II biosafety cabinet. A 23-year-old Class II, type A2 biosafety cabinet equipped with loaded HEPA filters and an inoperable blower was used for this study. Biological indicators were placed at various locations within the cabinet, including between the pleats of supply and exhaust HEPA filters, to assess the success of the decontamination processes. A variety of decontamination program cycle parameters in combination with two different routes of VHP introduction and minor biosafety cabinet preparations were assessed. Initial decontamination attempts using routine program cycles failed (at least one biological indicator grew upon incubation); however, program cycles consisting of modified parameters and BSC preparations resulted in successful (all the biological indicators were inactivated) and repeatable decontaminations. This study concludes that VHP, either wet or dry, could be used to decontaminate an entire biosafety cabinet only if appropriate and thoroughly validated decontamination processes are employed
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Decontamination of a Worst-Case Scenario Class II Biosafety Cabinet using Vaporous Hydrogen Peroxide:
Applied Biosafety, 2010Co-Authors: Greg Fey, Stan Klassen, Steven Theriault, Jay KrishnanAbstract:The objective of this study was to evaluate both condensing (wet) and non-condensing (dry) vaporous hydrogen peroxide (VHP) technologies for decontaminating a Worst-Case Scenario Class II biosafety...
Antony J. Lomax - One of the best experts on this subject based on the ideXlab platform.
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Advantages and limitations of the 'worst case Scenario' approach in IMPT treatment planning.
Physics in medicine and biology, 2013Co-Authors: M Casiraghi, Francesca Albertini, Antony J. LomaxAbstract:The 'worst case Scenario' (also known as the minimax approach in optimization terms) is a common approach to model the effect of delivery uncertainties in proton treatment planning. Using the 'dose-error-bar distribution' previously reported by our group as an example, we have investigated in more detail one of the underlying assumptions of this method. That is, the dose distributions calculated for a limited number of worst case patient positioning Scenarios (i.e. limited number of shifts sampled on a spherical surface) represent the worst dose distributions that can occur during the patient treatment under setup uncertainties. By uniformly sampling patient shifts from anywhere within a spherical error-space, a number of treatment Scenarios have been simulated and dose deviations from the nominal dose distribution have been computed. The dose errors from these simulations (comprehensive approach) have then been compared to the dose-error-bar approach previously reported (surface approximation) using both point-by-point and dose- and error-volume-histogram analysis (DVH/EVHs). This comparison has been performed for two different clinical cases treated using intensity modulated proton therapy (IMPT): a skull-base and a spinal-axis tumor. Point-by-point evaluation shows that the surface approximation leads to a correct estimation (95% accuracy) of the potential dose errors for the 96% and 85% of the irradiated voxels, for the two investigated cases respectively. We also found that the voxels for which the surface approximation fails are generally localized close to sharp soft tissue-bone interfaces and air cavities. Moreover, analysis of EVHs and DVHs for the two cases shows that the percentage of voxels of a given volume of interest potentially affected by a certain maximum dose error is correctly estimated using the surface approximation and that this approach also accurately predicts the upper and lower bounds of the DVH curves that can occur under positioning uncertainties. In conclusion, the assumption that the larger the patient shift the worse the dose error does not always hold on a point-by-point basis. Nevertheless, when performing a volumetric analysis, a limited set of worst case error Scenarios correctly represents the worst quality of the plan in presence of setup errors. As a consequence of these results, we believe that the worst case Scenario approach can be used in the IMPT planning procedure for estimating plan robustness provided that the possible limitations of this approach are known.
Chelsea Moran - One of the best experts on this subject based on the ideXlab platform.
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erratum to an exploratory study of the worst case Scenario exercise as an exposure treatment for fear of cancer recurrence
Supportive Care in Cancer, 2017Co-Authors: Chelsea Moran, Christina Tomei, Monique Lefebvre, Cheryl Harris, Christine Maheu, Sophie LebelAbstract:Purpose The Worst-Case Scenario (WCS) exercise is part of a manualized cognitive-existential group intervention for fear of cancer recurrence (FCR). It requires cancer survivors to describe the Scenario they most fear when they think about the possibility of their cancer returning and to re-read the Scenario daily for 1 week as homework. The purpose of this study was to present this novel clinical treatment for FCR and to examine whether at-home repeated exposure to the WCS was related to pre- and post-therapy FCR levels.