The Experts below are selected from a list of 35727 Experts worldwide ranked by ideXlab platform
Holger H Hoos - One of the best experts on this subject based on the ideXlab platform.
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model based algorithm configuration with default guided Probabilistic Sampling
Parallel Problem Solving from Nature, 2020Co-Authors: Marie Anastacio, Holger H HoosAbstract:In recent years, general-purpose automated algorithm configuration procedures have enabled impressive improvements in the state of the art in solving a wide range of challenging problems from AI, operations research and other areas. To search vast combinatorial spaces of parameter settings for a given algorithm as efficiently as possible, the most successful configurators combine techniques such as racing, estimation of distribution algorithms, Bayesian optimisation and model-free stochastic search. Two of the most widely used general-purpose algorithm configurators, SMAC and irace, can be seen as combinations of Bayesian optimisation and racing, and of racing and an estimation of distribution algorithm, respectively. Here, we propose a first approach that combines all three of these techniques into one single configurator, while exploiting prior knowledge contained in expert-chosen default parameter values. We demonstrate significant performance improvements over irace and SMAC on a broad range of running time optimisation scenarios from AClib.
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combining sequential model based algorithm configuration with default guided Probabilistic Sampling
Genetic and Evolutionary Computation Conference, 2020Co-Authors: Marie Anastacio, Holger H HoosAbstract:General-purpose automated algorithm configuration procedures have enabled impressive improvements in the state of the art in solving challenging problems from AI, operations research and other areas. The most successful configurators combine multiple techniques to search vast combinatorial spaces of parameter settings for a given algorithm as efficiently as possible. Specifically, two of the most prominent general-purpose algorithm configurators, SMAC and irace, can be seen as combinations of Bayesian optimisation and racing, and of racing and an estimation of distribution algorithm, respectively. Here, we investigate an approach that combines all three of these techniques into one single configurator, while exploiting prior knowledge contained in expert-chosen default parameter values. We demonstrate significant performance improvements over irace and SMAC on a broad range of running time optimisation scenarios from AClib.
Mark H Overmars - One of the best experts on this subject based on the ideXlab platform.
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using workspace information as a guide to non uniform Sampling in Probabilistic roadmap planners
The International Journal of Robotics Research, 2005Co-Authors: Jur Van Den Berg, Mark H OvermarsAbstract:The Probabilistic roadmap (PRM) planner is a popular method for robot motion planning problems with many degrees of freedom. However, it has been shown that the method performs less well in situations where the robot has to pass through a narrow passage in the scene. This is mainly due to the uniformity of the Sampling used in the planner; it places many samples in large open regions and too few in tight passages. Cell decomposition methods do not have this disadvantage, but are only applicable in low-dimensional configuration spaces. In this paper, a hybrid technique is presented that combines the strengths of both methods. It is based on a robot independent cell decomposition of the free workspace guiding the Probabilistic Sampling more toward the interesting regions in the configuration space. The regions of interest (narrow passages) are identified in the cell decomposition using a method we call watershed labeling. It is shown that this leads to improved performance on difficult planning problems in ...
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using workspace information as a guide to non uniform Sampling in Probabilistic roadmap planners
International Conference on Robotics and Automation, 2004Co-Authors: J P Van Den Berg, Mark H OvermarsAbstract:The Probabilistic roadmap (PRM) planner is a popular method for robot motion planning problems with many degrees of freedom. However, it has been shown that the method performs less well in situations where the robot has to pass through a narrow passage in the scene. This is mainly due to the uniformity of the Sampling used in the planner; it places many samples in large open regions and too few in tight passages. A technique based on a robot independent cell decomposition of the free workspace is proposed to guide the Probabilistic Sampling, such that the distribution of samples tends more toward the interesting regions in the scene. It is shown that this leads to improved performance on difficult planning problems in 2D and 3D workspaces.
Jonathan E Orozco - One of the best experts on this subject based on the ideXlab platform.
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design and implementation of the puerto rico observational study of psychosocial environmental and chronic disease trends prospect
American Journal of Epidemiology, 2020Co-Authors: Josiemer Mattei, Katherine L Tucker, Luis M Falcon, Carlos F Riosbedoya, Robert M Kaplan, June H Oneill, Martha Tamez, Sigrid Mendoza, Claudia B Diazalvarez, Jonathan E OrozcoAbstract:The Puerto Rico Observational Study of Psychosocial, Environmental, and Chronic Disease Trends (PROSPECT) is a prospective cohort study in Puerto Rico (PR) aiming to identify trends and longitudinal associations in risk factors for cardiovascular disease (CVD). In 2019, PROSPECT started recruiting a sample of 2,000 adults, ages 30-75 years, in PR using a multi-stage Probabilistic Sampling of households and community approaches. Culturally-sensitive trained research assistants assess participants, at baseline and at 2-year follow-up, in private rooms in a network of partner clinics. The study collects comprehensive data on demographics, socioeconomic and environmental factors, medical history, health conditions, lifestyle behaviors, psychosocial status, and biomarkers of CVD and stress. PROSPECT will estimate the prevalence and incidence of psychosocial, lifestyle, and biological CVD risk factors, describe variations in risk factors by urban versus rural area and after natural disasters, and determine predictors of longitudinal changes in CVD risk factors. The study has four coordinated operational strategies: (1) research productivity (including synergy with existing epidemiological cohorts of Hispanics/Latinos for comparison); (2) research infrastructure (biorepository, ancillary studies, and clinical research network); (3) capacity-building, education, and training; and (4) community outreach, dissemination, and policy. PROSPECT will inform public health priorities to help reduce CVD in PR.
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design and implementation of prospect puerto rico observational study of psychosocial environmental and chronic disease trends
American Journal of Epidemiology, 2020Co-Authors: Josiemer Mattei, Katherine L Tucker, Luis M Falcon, Carlos F Riosbedoya, Robert M Kaplan, June H Oneill, Martha Tamez, Sigrid Mendoza, Claudia B Diazalvarez, Jonathan E OrozcoAbstract:The Puerto Rico Observational Study of Psychosocial, Environmental, and Chronic Disease Trends (PROSPECT) is a prospective cohort study in Puerto Rico (PR) aiming to identify trends and longitudinal associations in risk factors for cardiovascular disease (CVD). In 2019, PROSPECT started recruiting a sample of 2,000 adults, ages 30-75 years, in PR using a multi-stage Probabilistic Sampling of households and community approaches. Culturally-sensitive trained research assistants assess participants, at baseline and at 2-year follow-up, in private rooms in a network of partner clinics. The study collects comprehensive data on demographics, socioeconomic and environmental factors, medical history, health conditions, lifestyle behaviors, psychosocial status, and biomarkers of CVD and stress. PROSPECT will estimate the prevalence and incidence of psychosocial, lifestyle, and biological CVD risk factors, describe variations in risk factors by urban versus rural area and after natural disasters, and determine predictors of longitudinal changes in CVD risk factors. The study has four coordinated operational strategies: (1) research productivity (including synergy with existing epidemiological cohorts of Hispanics/Latinos for comparison); (2) research infrastructure (biorepository, ancillary studies, and clinical research network); (3) capacity-building, education, and training; and (4) community outreach, dissemination, and policy. PROSPECT will inform public health priorities to help reduce CVD in PR.
Jeom Kee Paik - One of the best experts on this subject based on the ideXlab platform.
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quantitative collision risk assessment of a fixed type offshore platform with an offshore supply vessel
Structures, 2021Co-Authors: M P Mujeebahmed, Jeom Kee PaikAbstract:Abstract Offshore installations are designed to withstand against potential collisions from offshore supply vessels (OSV). Quantitative risk assessment (QRA) provides an overall picture of expected collision frequencies and consequences for the design life of a platform and subsequently estimates the damage repair cost. However, the main challenge of the QRA study is how well various uncertainties are implemented into the model. This study aimed to introduce and demonstrate an advanced and efficient QRA model for the collision between an OSV and a jacket type offshore platform. A set of fifty collision scenarios were selected using Probabilistic Sampling techniques, and vessel motion analyses were performed to determine collision load characteristics. Extensive nonlinear structural crashworthiness analyses were conducted using advanced computational modelling techniques, and the repair cost of the damaged brace and column members were calculated. Probability exceedance diagrams were established for different consequence parameters, and asset risks were calculated. A comparison study of the design values of damage parameters and repair costs were carried out in association with the NORSOK and HSE risk acceptance criteria. A sensitivity study was carried out to study the effects of various collision load parameters on the structural consequences. The methods and insights developed in this study could be applied to both new and existing offshore platforms and practically useful for the platform owners to aid in their decision-making process towards the risk-based safety analysis of offshore platforms.
Josiemer Mattei - One of the best experts on this subject based on the ideXlab platform.
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design and implementation of the puerto rico observational study of psychosocial environmental and chronic disease trends prospect
American Journal of Epidemiology, 2020Co-Authors: Josiemer Mattei, Katherine L Tucker, Luis M Falcon, Carlos F Riosbedoya, Robert M Kaplan, June H Oneill, Martha Tamez, Sigrid Mendoza, Claudia B Diazalvarez, Jonathan E OrozcoAbstract:The Puerto Rico Observational Study of Psychosocial, Environmental, and Chronic Disease Trends (PROSPECT) is a prospective cohort study in Puerto Rico (PR) aiming to identify trends and longitudinal associations in risk factors for cardiovascular disease (CVD). In 2019, PROSPECT started recruiting a sample of 2,000 adults, ages 30-75 years, in PR using a multi-stage Probabilistic Sampling of households and community approaches. Culturally-sensitive trained research assistants assess participants, at baseline and at 2-year follow-up, in private rooms in a network of partner clinics. The study collects comprehensive data on demographics, socioeconomic and environmental factors, medical history, health conditions, lifestyle behaviors, psychosocial status, and biomarkers of CVD and stress. PROSPECT will estimate the prevalence and incidence of psychosocial, lifestyle, and biological CVD risk factors, describe variations in risk factors by urban versus rural area and after natural disasters, and determine predictors of longitudinal changes in CVD risk factors. The study has four coordinated operational strategies: (1) research productivity (including synergy with existing epidemiological cohorts of Hispanics/Latinos for comparison); (2) research infrastructure (biorepository, ancillary studies, and clinical research network); (3) capacity-building, education, and training; and (4) community outreach, dissemination, and policy. PROSPECT will inform public health priorities to help reduce CVD in PR.
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design and implementation of prospect puerto rico observational study of psychosocial environmental and chronic disease trends
American Journal of Epidemiology, 2020Co-Authors: Josiemer Mattei, Katherine L Tucker, Luis M Falcon, Carlos F Riosbedoya, Robert M Kaplan, June H Oneill, Martha Tamez, Sigrid Mendoza, Claudia B Diazalvarez, Jonathan E OrozcoAbstract:The Puerto Rico Observational Study of Psychosocial, Environmental, and Chronic Disease Trends (PROSPECT) is a prospective cohort study in Puerto Rico (PR) aiming to identify trends and longitudinal associations in risk factors for cardiovascular disease (CVD). In 2019, PROSPECT started recruiting a sample of 2,000 adults, ages 30-75 years, in PR using a multi-stage Probabilistic Sampling of households and community approaches. Culturally-sensitive trained research assistants assess participants, at baseline and at 2-year follow-up, in private rooms in a network of partner clinics. The study collects comprehensive data on demographics, socioeconomic and environmental factors, medical history, health conditions, lifestyle behaviors, psychosocial status, and biomarkers of CVD and stress. PROSPECT will estimate the prevalence and incidence of psychosocial, lifestyle, and biological CVD risk factors, describe variations in risk factors by urban versus rural area and after natural disasters, and determine predictors of longitudinal changes in CVD risk factors. The study has four coordinated operational strategies: (1) research productivity (including synergy with existing epidemiological cohorts of Hispanics/Latinos for comparison); (2) research infrastructure (biorepository, ancillary studies, and clinical research network); (3) capacity-building, education, and training; and (4) community outreach, dissemination, and policy. PROSPECT will inform public health priorities to help reduce CVD in PR.