9 research outputs found
RESILIENCE OF TRANSPORTATION INFRASTRUCTURE SYSTEMS: QUANTIFICATION AND OPTIMIZATION
Transportation systems are critical lifelines for society, but are at risk from natural or human-caused hazards. To prevent significant loss from disaster events caused by such hazards, the transportation system must be resilient, and thus able to cope with disaster impact. It is impractical to reinforce or harden these systems to all types of events. However, options that support quick recovery of these systems and increase the system's resilience to such events may be helpful.
To address these challenges, this dissertation provides a general mathematical framework to protect transportation infrastructure systems in the presence of uncertain events with the potential to reduce system capacity/performance. A single, general decision-support optimization model is formulated as a multi-stage stochastic program. The program seeks an optimal sequence of decisions over time based upon the realization of random events in each time stage. This dissertation addresses three problems to demonstrate the application of the proposed mathematical model in different transportation environments with emphasis on system-level resilience: Airport Resilience Problem (ARP), Building Evacuation Design Problem (BEDP), and Travel Time Resilience in Roadways (TTR). These problems aim to measure system performance given the system's topological and operational characteristics and support operational decision-making, mitigation and preparedness planning, and post-event immediate response. Mathematical optimization techniques including, bi-level programming, nonlinear programming, stochastic programming and robust optimization, are employed in the formulation of each problem. Exact (or approximate) solution methodologies based on concepts of primal and dual decomposition (integer L-shaped decomposition, Generalized Benders decomposition, and progressive hedging), disjunctive optimization, scenario simulation, and piecewise linearization methods are presented. Numerical experiments were conducted on network representations of a United States rail-based intermodal container network, the LaGuardia Airport taxiway and runway pavement network, a single-story office building, and a small roadway network
Resilience of Networked Infrastructure with Evolving Component Conditions: Pavement Network Application
Resilience of Networked Infrastructure with Evolving Component Conditions: Pavement Network Application
Medical Podcasting in Iran; Pilot, Implementation and Attitude Evaluation
Podcasting has become a popular means of transferring knowledge in higher education through making lecture contents available to students at their convenience. Accessing courses on media players provides students with enhanced learning opportunities. Development of teaching methods able to cope with ever-changing nature of medicine is crucial to train the millennium students. Pharmacology education in Tehran University of Medical Sciences has been based on lectures so far; our aim was to implement a pilot study to evaluate the advantages and disadvantages of offering the course contents as podcasts as well as evaluating whether such program can be feasible in our educational program. 46% of students downloaded the podcast according to our download center. 48% favored usage of both internet and DVD-ROM concurrently. Overall 96% of students perceived that podcasting had a positive impact on their learning in pharmacology course. Our results indicate that most of attendants proposed the positive yields of podcasting despite low usage of it, mainly as a pre-class preparing tool
A comparative study on the elastic modulus of polyvinyl alcohol sponge using different stress-strain definitions
Low-altitude UAV-borne remote sensing in dunes environment: Shoreline monitoring and coastal resilience
UAV systems, fitted with either active or passive surveying sensors, can provide land-related measures and quantitative information with low costs and high resolution in both space and time. Such surveying systems can be quite valuable in defining geometrical and descriptive parameters in coastal systems, especially dune ecosystems. The present work is based on a survey of the dune system at the mouth of the Fiume Morto Nuovo in the San Rossore Estate (Pisa) and focuses on comparing LiDAR with UAV- and airplane-borne photogrammetry, as well as the respective 2D and 3D cartographic output, in order to assess topography changes along a stretch of coastline and to check their possible use in defining some ecological resilience features on coastal dune systems. Processing of survey data generates a Digital Surface Model (DSM) or Digital Terrain Model (DTM) and an orthophotograph, checked for accuracy and image resolution. Comparison of these products against those available in public access cartographical databases highlights differences and respective strengths