The Experts below are selected from a list of 377514 Experts worldwide ranked by ideXlab platform
B. O'connor - One of the best experts on this subject based on the ideXlab platform.
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control of variable speed wind turbines Design Task
International Journal of Control, 2000Co-Authors: William E. Leithead, B. O'connorAbstract:Owing to concern over the environment, there is much interest in renewable sources of electrical power generation, of which one of the most promising is wind power. There are essentially two types of wind turbines, namely constant speed and variable speed machines. In comparison to constant speed wind turbines, variable speed wind turbines are perceived to have several potential advantages which outweigh the considerable cost of the power electronics required to realize variable speed operation. The two frequently mentioned ones are: additional energy capture below rated wind speed and additional power-train compliance and associated load alleviation above rated wind speed. The purpose of this paper is to investigate the Design of the control system (as opposed to the synthesis of the controller) for variable speed wind turbines. The choice of control strategy is investigated and appropriate realizations of the controller, to cater for the implementation issues of accommodation of variation in the plant d...
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control of variable speed wind turbines dynamic models
International Journal of Control, 2000Co-Authors: William E. Leithead, B. O'connorAbstract:Owing to concern over the environment, there is much interest in renewable sources of electrical power generation, of which one of the most promising is wind power. Wind turbines exploit this energy source to directly generate electrical power. There are essentially two types of windturbines, namely constant speed and variable speed machines. The purpose of this paper is to investigate the dynamics of variable speed wind turbines and determine suitable models to support the control Design Task. A basic but widely used dynamic representation of variable speed wind turbines and the corresponding models of the control plant dynamics are initially discussed. More detailed, yet still simple models, are derived separately for the rotor aerodynamics, the drive-train dynamics and the power generation unit dynamics before being combined to form the complete model of the wind turbine dynamics. The resulting combined model, in addition to supporting the control Design Task, enables the extent, to which the basic mod...
William E. Leithead - One of the best experts on this subject based on the ideXlab platform.
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control of variable speed wind turbines Design Task
International Journal of Control, 2000Co-Authors: William E. Leithead, B. O'connorAbstract:Owing to concern over the environment, there is much interest in renewable sources of electrical power generation, of which one of the most promising is wind power. There are essentially two types of wind turbines, namely constant speed and variable speed machines. In comparison to constant speed wind turbines, variable speed wind turbines are perceived to have several potential advantages which outweigh the considerable cost of the power electronics required to realize variable speed operation. The two frequently mentioned ones are: additional energy capture below rated wind speed and additional power-train compliance and associated load alleviation above rated wind speed. The purpose of this paper is to investigate the Design of the control system (as opposed to the synthesis of the controller) for variable speed wind turbines. The choice of control strategy is investigated and appropriate realizations of the controller, to cater for the implementation issues of accommodation of variation in the plant d...
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control of variable speed wind turbines dynamic models
International Journal of Control, 2000Co-Authors: William E. Leithead, B. O'connorAbstract:Owing to concern over the environment, there is much interest in renewable sources of electrical power generation, of which one of the most promising is wind power. Wind turbines exploit this energy source to directly generate electrical power. There are essentially two types of windturbines, namely constant speed and variable speed machines. The purpose of this paper is to investigate the dynamics of variable speed wind turbines and determine suitable models to support the control Design Task. A basic but widely used dynamic representation of variable speed wind turbines and the corresponding models of the control plant dynamics are initially discussed. More detailed, yet still simple models, are derived separately for the rotor aerodynamics, the drive-train dynamics and the power generation unit dynamics before being combined to form the complete model of the wind turbine dynamics. The resulting combined model, in addition to supporting the control Design Task, enables the extent, to which the basic mod...
Mark J Ratain - One of the best experts on this subject based on the ideXlab platform.
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impact of the 2010 consensus recommendations of the clinical trial Design Task force of the nci investigational drug steering committee
Clinical Cancer Research, 2015Co-Authors: Lesley Seymour, Percy S Ivy, Susan Groshen, Gary L Rosner, Daniel M Sullivan, David R Spriggs, Steven A Reeves, Amy Gravell, Mark J RatainAbstract:Oncology phase III trials have a high failure rate, leading to high development costs. The Clinical Trials Design Task Force of the Investigational Drug Steering Committee of the NCI Cancer Therapy and Evaluation Program developed Recommendations regarding the Design of phase II trials. We report here on the results of a Concordance Group review charged with documenting whether concordance rates improved after the publication of the Recommendations. One hundred and fifty-five trials were reviewed. Letter of Intents (LOI) from the post-Recommendation period were more likely to be randomized (44% vs. 34%) and biomarker selected (19% vs. 10%). Single-arm studies using time-to-event endpoints (benchmarked against historical data) were similar, as was the type of tumor. There was a significant improvement in the rate of concordance, with 74% of LOIs scored as concordant compared with 58% before the Recommendations (P = 0.042). This included a marked decrease in the use of single-arm Designs to evaluate the activity of drug combinations (19% vs. 5%, P = 0.009). There were areas for which clarification was warranted, including the need for protocols to include further development plans, the use of realistic benchmarks, the careful evaluation of historical controls, and the use of a standard treatment option as a control. Ongoing critical evaluation of current trial Design methodology and the development of new Guidelines when appropriate will continue to improve drug development ensuring that safe and effective cancer therapeutics are made available to our patients as quickly and efficiently as possible.
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the Design of phase ii clinical trials testing cancer therapeutics consensus recommendations from the clinical trial Design Task force of the national cancer institute investigational drug steering committee
Clinical Cancer Research, 2010Co-Authors: Lesley Seymour, Larry Rubinstein, Percy S Ivy, Laurence H Baker, David R Spriggs, Mark J Ratain, Daniel J Sargent, Michael Le Blanc, David J Stewart, John CrowleyAbstract:The optimal Design of phase II studies continues to be the subject of vigorous debate, especially studies of newer molecularly targeted agents. The observations that many new therapeutics "fail" in definitive phase III studies, coupled with the numbers of new agents to be tested as well as the increasing costs and complexity of clinical trials, further emphasize the critical importance of robust and efficient phase II Design. The Clinical Trial Design Task Force (CTD-TF) of the National Cancer Institute (NCI) Investigational Drug Steering Committee (IDSC) has published a series of discussion papers on phase II trial Design in Clinical Cancer Research. The IDSC has developed formal recommendations about aspects of phase II trial Design that are the subject of frequent debate, such as endpoints (response versus progression-free survival), randomization (single-arm Designs versus randomization), inclusion of biomarkers, biomarker-based patient enrichment strategies, and statistical Design (e.g., two-stage Designs versus multiple-group adaptive Designs). Although these recommendations in general encourage the use of progression-free survival as the primary endpoint, randomization, inclusion of biomarkers, and incorporation of newer Designs, we acknowledge that objective response as an endpoint and single-arm Designs remain relevant in certain situations. The Design of any clinical trial should always be carefully evaluated and justified based on characteristic specific to the situation.
Lesley Seymour - One of the best experts on this subject based on the ideXlab platform.
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impact of the 2010 consensus recommendations of the clinical trial Design Task force of the nci investigational drug steering committee
Clinical Cancer Research, 2015Co-Authors: Lesley Seymour, Percy S Ivy, Susan Groshen, Gary L Rosner, Daniel M Sullivan, David R Spriggs, Steven A Reeves, Amy Gravell, Mark J RatainAbstract:Oncology phase III trials have a high failure rate, leading to high development costs. The Clinical Trials Design Task Force of the Investigational Drug Steering Committee of the NCI Cancer Therapy and Evaluation Program developed Recommendations regarding the Design of phase II trials. We report here on the results of a Concordance Group review charged with documenting whether concordance rates improved after the publication of the Recommendations. One hundred and fifty-five trials were reviewed. Letter of Intents (LOI) from the post-Recommendation period were more likely to be randomized (44% vs. 34%) and biomarker selected (19% vs. 10%). Single-arm studies using time-to-event endpoints (benchmarked against historical data) were similar, as was the type of tumor. There was a significant improvement in the rate of concordance, with 74% of LOIs scored as concordant compared with 58% before the Recommendations (P = 0.042). This included a marked decrease in the use of single-arm Designs to evaluate the activity of drug combinations (19% vs. 5%, P = 0.009). There were areas for which clarification was warranted, including the need for protocols to include further development plans, the use of realistic benchmarks, the careful evaluation of historical controls, and the use of a standard treatment option as a control. Ongoing critical evaluation of current trial Design methodology and the development of new Guidelines when appropriate will continue to improve drug development ensuring that safe and effective cancer therapeutics are made available to our patients as quickly and efficiently as possible.
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the Design of phase ii clinical trials testing cancer therapeutics consensus recommendations from the clinical trial Design Task force of the national cancer institute investigational drug steering committee
Clinical Cancer Research, 2010Co-Authors: Lesley Seymour, Larry Rubinstein, Percy S Ivy, Laurence H Baker, David R Spriggs, Mark J Ratain, Daniel J Sargent, Michael Le Blanc, David J Stewart, John CrowleyAbstract:The optimal Design of phase II studies continues to be the subject of vigorous debate, especially studies of newer molecularly targeted agents. The observations that many new therapeutics "fail" in definitive phase III studies, coupled with the numbers of new agents to be tested as well as the increasing costs and complexity of clinical trials, further emphasize the critical importance of robust and efficient phase II Design. The Clinical Trial Design Task Force (CTD-TF) of the National Cancer Institute (NCI) Investigational Drug Steering Committee (IDSC) has published a series of discussion papers on phase II trial Design in Clinical Cancer Research. The IDSC has developed formal recommendations about aspects of phase II trial Design that are the subject of frequent debate, such as endpoints (response versus progression-free survival), randomization (single-arm Designs versus randomization), inclusion of biomarkers, biomarker-based patient enrichment strategies, and statistical Design (e.g., two-stage Designs versus multiple-group adaptive Designs). Although these recommendations in general encourage the use of progression-free survival as the primary endpoint, randomization, inclusion of biomarkers, and incorporation of newer Designs, we acknowledge that objective response as an endpoint and single-arm Designs remain relevant in certain situations. The Design of any clinical trial should always be carefully evaluated and justified based on characteristic specific to the situation.
Storeymargaret-anne - One of the best experts on this subject based on the ideXlab platform.
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Comparing horizontal and vertical surfaces for a collaborative Design Task
Advances in Human-computer Interaction, 2012Co-Authors: Potvinbrianna, Swindellscolin, Torymelanie, Storeymargaret-anneAbstract:We investigate the use of different surface orientations for collaborative Design Tasks. Specifically, we compare horizontal and vertical surface orientations used by dyads performing a collaborati...