96 research outputs found

    Adaptive Ranking Based Constraint Handling for Explicitly Constrained Black-Box Optimization

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    A novel explicit constraint handling technique for the covariance matrix adaptation evolution strategy (CMA-ES) is proposed. The proposed constraint handling exhibits two invariance properties. One is the invariance to arbitrary element-wise increasing transformation of the objective and constraint functions. The other is the invariance to arbitrary affine transformation of the search space. The proposed technique virtually transforms a constrained optimization problem into an unconstrained optimization problem by considering an adaptive weighted sum of the ranking of the objective function values and the ranking of the constraint violations that are measured by the Mahalanobis distance between each candidate solution to its projection onto the boundary of the constraints. Simulation results are presented and show that the CMA-ES with the proposed constraint handling exhibits the affine invariance and performs similarly to the CMA-ES on unconstrained counterparts.Comment: 9 page

    Aeronautical engineering: A cumulative index to a continuing bibliography

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    This bibliography is a cumulative index to the abstracts contained in NASA SP-7037(210) through NASA SP-7037(221) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, foreign technology, contract number, report number, and accession number indexes

    Roentgen stereophotogrammetric analysis to study dynamics and migration of stent grafts

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    The technique of RSA to determine stent-graft migration and FRSA to study stent-graft dynamics are explained in further detail in CHAPTER 2. CHAPTER 3 and 4 concern the accuracy and feasibility of RSA to detect stent-graft migration in a static model and in a model with pulsatile motion. The results are compared to CT, the current clinical gold standard. RSA requires an aortic reference marker to detect stent-graft migration. A possible aortic reference marker is studied in CHAPTER 4 and 5. In CHAPTER 5, the feasibility of RSA in vivo is described. Furthermore, the position and the number of aortic reference markers required for accurate analysis needs to be clarified. These issues are discussed in CHAPTERS 5 and 6. Plain abdominal radiography is widely used as a low cost method to determine stent-graft migration. In CHAPTER 7, a study on the accuracy and, therefore, clinical applicability of plain abdominal radiography to detect stent-graft migration is described.In CHAPTER 8 the feasibility of FRSA is studied in a model and the method is validated for accuracy and precision. In CHAPTER 9, the first clinical introduction of this technique is reported. To conclude this thesis, the risk of radiation due to imaging for EVAR is evaluated in CHAPTER 10.UBL - phd migration 201

    Virtuelle endovaskuläre Versorgung von abdominalen Aortenaneurysmen

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    This thesis is focused on computational methods that predict the outcome of endovascular repair of abdominal aortic aneurysms. Novelties include improvements of the aneurysm model, the stent-graft model as well as the in-silico stent-graft placement methodology. The newly developed methods are applied to patient-specific cases and are validated against real-world postinterventional data. Further, directions for using the in-silico model of endovascular aneurysm repair as personalized preinterventional planning tool in clinical practice are provided.Die vorliegende Arbeit beschäftigt sich mit numerischen Methoden um den Ausgang einer endovaskulären Versorgung von abdominalen Aortenaneurysmen vorherzusagen. Neuheiten umfassen Verbesserungen des Aneurysmenmodells, des Stentgraftmodells sowie der virtuellen Platzierungsmethode des Stentgrafts. Die neu entwickelten Methoden werden auf patientenspezifische Fälle angewandt und werden mit realen postoperativen Daten validiert. Weiterhin werden klinische Anwendungen des Modells der endovaskulären Aneurysmenversorgung als personalisiertes präoperatives Planungswerkzeug präsentiert

    Aeronautical Engineering: A special bibliography with indexes, supplement 90

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    This bibliography lists 351 reports, articles, and other documents introduced into the NASA scientific and technical information system in November 1977

    Aeronautical engineering: A continuing bibliography with indexes (supplement 219)

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    This bibliography lists 586 reports, articles, and other documents introduced into the NASA scientific and technical information system in October, 1987

    Virtuelle endovaskuläre Versorgung von abdominalen Aortenaneurysmen

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    This thesis is focused on computational methods that predict the outcome of endovascular repair of abdominal aortic aneurysms. Novelties include improvements of the aneurysm model, the stent-graft model as well as the in-silico stent-graft placement methodology. The newly developed methods are applied to patient-specific cases and are validated against real-world postinterventional data. Further, directions for using the in-silico model of endovascular aneurysm repair as personalized preinterventional planning tool in clinical practice are provided.Die vorliegende Arbeit beschäftigt sich mit numerischen Methoden um den Ausgang einer endovaskulären Versorgung von abdominalen Aortenaneurysmen vorherzusagen. Neuheiten umfassen Verbesserungen des Aneurysmenmodells, des Stentgraftmodells sowie der virtuellen Platzierungsmethode des Stentgrafts. Die neu entwickelten Methoden werden auf patientenspezifische Fälle angewandt und werden mit realen postoperativen Daten validiert. Weiterhin werden klinische Anwendungen des Modells der endovaskulären Aneurysmenversorgung als personalisiertes präoperatives Planungswerkzeug präsentiert

    Aeronautical Engineering: A continuing bibliography, supplement 96

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    This bibliography lists 448 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1978

    The International Linear Collider Technical Design Report - Volume 4: Detectors

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    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.Comment: See also http://www.linearcollider.org/ILC/TDR . The full list of signatories is inside the Repor

    Aeronautical Engineering: A cumulative index to the 1980 issue

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    This bibliography is a cumulative index to reports, articles, and other documents introduced into the NASA scientific and technical information system. Abstracts for the entries cited appeared in issues 119 through 130 of Aeronautical Engineering: A Continuing Bibliography (NASA SP-7037). Subject, personal author, corporate author, contract number, and report/accession number indexes are provided
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