Search results for "Crete"
showing 10 items of 2495 documents
Analysis of curved incrementally launched box concrete bridges using the Transfer Matrix Method
2007
Incrementally launching technique is today very competitive for the construction of continuous concrete bridges. During construction the static scheme of these bridges varies continuously, with the advance of the deck above piers, producing temporary stresses rather different from those occurring in service. An approach to analyse construction phases of curved incrementally launched bridges is presented for concrete single box girder, using the Transfer Matrix Method. A procedure based on this method, already developed for straight launched bridges, has been extended to curved beams, allowing engineers to estimate the effects of horizontal curvature during the entire launching process. This…
Simultaneous measurement of temperature and strain in glass fiber/epoxy composites by embedded fiber optic sensors: II. Post-cure testing
2007
In this paper the use of fiber optic sensors embedded into GFRP laminates for structural health monitoring of thermo-mechanical loads is presented. The proposed sensing system, consisting of two coupled fiber Bragg grating (FBG) sensors, allows the simultaneous measurement of both temperature and strain by decoupling the change in reflected wavelength induced by temperature variations from that induced by either mechanical or apparent strain, with significant advantages either for monitoring the composite cure kinetics, as described in the accompanying paper (Part I), or for assessing the structural response to thermo-mechanical loads. Both thermal ramp and mechanical static/dynamic bending…
Adaptive high-gain extended kalman filter and applications
2010
The work concerns the ``observability problem” --- the reconstruction of a dynamic process's full state from a partially measured state--- for nonlinear dynamic systems. The Extended Kalman Filter (EKF) is a widely-used observer for such nonlinear systems. However it suffers from a lack of theoretical justifications and displays poor performance when the estimated state is far from the real state, e.g. due to large perturbations, a poor initial state estimate, etc… We propose a solution to these problems, the Adaptive High-Gain (EKF). Observability theory reveals the existence of special representations characterizing nonlinear systems having the observability property. Such representations…
A Dido problem for domains in ?2 with a given inradius
1990
We find which are the simply connected domains in ℝ2 satisfying the Dido condition for a straight shoreline, with a given area A and a fixed inradius ϱ, which minimize the length of the free boundary. There are three different cases according to the values of A and ϱ.
FRIPON: a worldwide network to track incoming meteoroids
2020
Context. Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as the most fragile - hence precious - meteorites must be recovered rapidly to avoid their alteration. Aims. The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receiver…
Modal Analysis of a Reinforced Concrete Frame in Various States of Damage
2005
The purpose of this paper is to report selected results of an experiment in which two, natural size r/c frames were put on shaking table and subjected to a sequence of seismic excitations with increasing intensity interlaced with low level, diagnostic tests. The shaking table experiment aimed at working out new methodology for monitoring vibrations of r/c structures to assess their state. Characteristic decrease of natural frequencies and increase of structural damping was observed and analyzed in detail. It was interesting to note 20 per cent drop in natural frequencies prior to visual detection of any cracks.
Monitoring road pavement performance through a novel data processing approach, accelerated pavement test results
2020
This research presents a novel performance-based interpretation method for continuous monitoring of pavement condition through the use of piezoelectric sensors. The objective of this study is to validate the compressed cumulative loading event approach, implemented in a previously developed piezoelectric sensor, for detecting subsurface fatigue cracking through full-scale accelerated pavement testing. A piezo-electric film of polyvinylidene fluoride is used to harvest the microstrain energy induced by the traffic loading at the surface. Epoxy is used to protect the sensor following a H-shape packaging. Piezoelectric sensors were exposed to approximately 1.0 million load repetitions between …
New results for finding common neighborhoods in massive graphs in the data stream model
2008
AbstractWe consider the problem of finding pairs of vertices that share large common neighborhoods in massive graphs. We give lower bounds for randomized, two-sided error algorithms that solve this problem in the data-stream model of computation. Our results correct and improve those of Buchsbaum, Giancarlo, and Westbrook [On finding common neighborhoods in massive graphs, Theoretical Computer Science, 299 (1–3) 707–718 (2004)]
Dynamic graph visualization
2011
Qualification work "Graph dynamic Visualization" describes the graph dynamic and development of display tool. Tool is designed to represent the changes in graph on a timeline. This allows the user to visually create the graph, change it and create views, saving all graph changes, and fetch information on the displayed graph views of the files. The tool is created in programming languageJava. The development is fully documented, including the requirement specification, design and testing. Keywords: graphs, dynamic graphs, graph display, Java.
Multidimensionālu attēlu spektrālo joslu ekvivalentas redukcijas pieejas objektu klasifikācijai
2019
Darbs veltīts multidimensionālu attēlu apstrādes problēmām, kas saistītas ar šo attēlu spektrālo joslu izvēli un pikseļu klasifikāciju. Izstrādātas jaunas, relatīvi vienkāršas un vispārīgas nevadītās: EMCR, EXCR, ESCR, ECBG un vadītā: XECT joslu izvēles procedūras informatīvu spektrālo joslu komplektu noteikšanai hiperspektrālajos attēlos. Informativitāte tika pārbaudīta ar Beijesa, k-NN, SVM, ELM un citiem klasifikatoriem, no kuriem augstāku klasifikācijas precizitāti sniedza SVM, izmantojot ECBG procedūru. Atslēgvārdi: hiperspketrālu attēlu apstrāde, spektrālo joslu izvēle, hiperspektrālu attēlu klasifikācija, tālizpēte