Visual retrieval of concrete crack properties for automated post-earthquake structural safety evaluation

The safety of post-earthquake structures is evaluated manually through inspecting the visible damage inflicted on structural elements. This process is time-consuming and costly. In order to automate this type of assessment, several crack detection methods have been created. However, they focus on locating crack points. The next step, retrieving useful properties (e.g. crack width, length, and orientation) from the crack points, has not yet been adequately investigated. This paper presents a novel method of retrieving crack properties. In the method, crack points are first located through state-of-the-art crack detection techniques. Then, the skeleton configurations of the points are identified using image thinning. The configurations are integrated into the distance field of crack points calculated through a distance transform. This way, crack width, length, and orientation can be automatically retrieved. The method was implemented using Microsoft Visual Studio and its effectiveness was tested on real crack images collected from Haiti.

Visual pattern recognition models for remote sensing of civil infrastructure

As-built models have been proven useful in many project-related applications, such as progress monitoring and quality control. However, they are not widely produced in most projects because a lot of effort is still necessary to manually convert remote sensing data from photogrammetry or laser scanning to an as-built model. In order to automate the generation of as-built models, the first and fundamental step is to automatically recognize infrastructure-related elements from the remote sensing data. This paper outlines a framework for creating visual pattern recognition models that can automate the recognition of infrastructure-related elements based on their visual features. The framework starts with identifying the visual characteristics of infrastructure element types and numerically representing them using image analysis tools. The derived representations, along with their relative topology, are then used to form element visual pattern recognition (VPR) models. So far, the VPR models of four infrastructure-related elements have been created using the framework. The high recognition performance of these models validates the effectiveness of the framework in recognizing infrastructure-related elements.

Detection of large-scale concrete columns for automated bridge inspection

There are over 600,000 bridges in the US, and not all of them can be inspected and maintained within the specified time frame. This is because manually inspecting bridges is a time-consuming and costly task, and some state Departments of Transportation (DOT) cannot afford the essential costs and manpower. In this paper, a novel method that can detect large-scale bridge concrete columns is proposed for the purpose of eventually creating an automated bridge condition assessment system. The method employs image stitching techniques (feature detection and matching, image affine transformation and blending) to combine images containing different segments of one column into a single image. Following that, bridge columns are detected by locating their boundaries and classifying the material within each boundary in the stitched image. Preliminary test results of 114 concrete bridge columns stitched from 373 close-up, partial images of the columns indicate that the method can correctly detect 89.7% of these elements, and thus, the viability of the application of this research.

Large Scale Column Detection for Bridge Inspection

Manually inspecting bridges is a time-consuming and costly task. There are over 600,000 bridges in the US, and not all of them can be inspected and maintained within the specified time frame as some state DOTs cannot afford the essential costs and manpower. This paper presents a novel method that can detect bridge concrete columns from visual data for the purpose of eventually creating an automated bridge condition assessment system. The method employs SIFT feature detection and matching to find overlapping areas among images. Affine transformation matrices are then calculated to combine images containing different segments of one column into a single image. Following that, the bridge columns are detected by identifying the boundaries in the stitched image and classifying the material within each boundary. Preliminary test results using real bridge images indicate that most columns in stitched images can be correctly detected and thus, the viability of the application of this research.

Machine Vision Enhanced Post-earthquake Inspection

Camera motion estimation is one of the most significant steps for structure-from-motion (SFM) with a monocular camera. The normalized 8-point, the 7-point, and the 5-point algorithms are normally adopted to perform the estimation, each of which has distinct performance characteristics. Given unique needs and challenges associated to civil infrastructure SFM scenarios, selection of the proper algorithm directly impacts the structure reconstruction results. In this paper, a comparison study of the aforementioned algorithms is conducted to identify the most suitable algorithm, in terms of accuracy and reliability, for reconstructing civil infrastructure. The free variables tested are baseline, depth, and motion. A concrete girder bridge was selected as the "test-bed" to reconstruct using an off-the-shelf camera capturing imagery from all possible positions that maximally the bridge's features and geometry. The feature points in the images were extracted and matched via the SURF descriptor. Finally, camera motions are estimated based on the corresponding image points by applying the aforementioned algorithms, and the results evaluated.

CO2-gasification of a lignite coal in the presence of an iron-based oxygen carrier for chemical-looping combustion

Chemical-looping combustion (CLC) has the inherent property of separating the product CO2 from flue gases. Instead of air, it uses an oxygen carrier, usually in the form of a metal oxide, to provide oxygen for combustion. All techniques so far proposed for chemical looping with solid fuels involve initially the gasification of the solid fuel in order for the gaseous products to react with the oxygen carrier. Here, the rates of gasification of coal were compared when gasification was undertaken in a fluidised bed of either (i) an active Fe-based oxygen carrier used for chemical looping or (ii) inert sand. This enabled an examination of the ability of chemical looping materials to enhance the rate of gasification of solid fuels. Batch gasification and chemical-looping combustion experiments with a German lignite and its char are reported, using an electrically-heated fluidised bed reactor at temperatures from 1073 to 1223 K. The fluidising gas was CO2 in nitrogen. The kinetics of the gasification were found to be significantly faster in the presence of the oxygen carrier, especially at temperatures above 1123 K. A numerical model was developed to account for external and internal mass transfer and for the effect of the looping agent. The model also included the effects of the evolution of the pore structure at different conversions. The presence of Fe2O3 led to an increase in the rate of gasification because of the rapid oxidation of CO by the oxygen carrier to CO2. This resulted in the removal of CO and maintained a higher mole fraction of CO2 in the mixture of gas around the particle of char, i.e. within the mass transfer boundary layer surrounding the particle. This effect was most prominent at about 20% conversion when (i) the surface area for reaction was at its maximum and (ii) because of the accompanying increase in porosity and pore size, intraparticle resistance to gas mass transfer within the particle of char had fallen, compared with that in the initial particle. Excellent agreement was observed between the rates predicted by the numerical model and those observed experimentally. ©2013 Elsevier Ltd. All rights reserved.

Einfallstor in die Sowjetunion: Die Besatzung Deutschlands und die Aussp?hung der UdSSR durch den britischen Nachrichtendienst?

Maddrell, John, 'Einfallstor in die Sowjetunion: Die Besatzung Deutschlands und die Aussp?hung der UdSSR durch den britischen Nachrichtendienst', Vierteljahrshefte f?r Zeitgeschichte (2003) 51(2) pp.183-227 RAE2008

Kazimierz Kaczmarczyk (1878-1966). Archiwista i historyk

Wydział Historyczny: Instytut Historii

Zastosowanie podcastów w rozwijaniu sprawności słuchania ze zrozumieniem w języku obcym na przykładzie studentów germanistyki i lingwistyki stosowanej w Polsce

Wydział Neofilologii

Polskie Wojska Lotnicze w okresie walk o granice państwa polskiego (1918-1921)

Wydział Historyczny

Sonata Development at the Turn of the Century: From Liszt to Stravinsky

The sonata began to lose its position of predominance among compositions in the middle of the 19th century. Having been the platform for harmonic and thematic development of music since the late baroque period the sonata entered a process of reevaluation and experimentation with form. As a result fewer sonatas were being composed with some composers dropping the genre completely. This dissertation looks at the different approaches taken by the German, French and Russian schools of composition and compares the solo and chamber music applications of the sonata form. In the German tradition Franz Liszt's Sonata in b minor sets the standard for the revolutionary approach to form while the Berg Sonata is a very conservative application of form to an innovative use of extended chromaticism. Both composers chose to write one movement through composed pieces with Liszt working with a very expansive use of form and Berg being extremely compact and efficient. Among the Russian composers, Prokofieff's third sonata is also a one movement sonata, but he falls between Liszt and Berg in terms of the length of the piece and the use of innovative musical language. Scriabin uses a two movement approach, but keeps the element of a through composed piece with the same important material spanning both movements. Stravinsky is the most conservative of these with a three movement sonata that uses a mix of chromaticism and baroque and classical style influences. The French almost stopped composing true sonatas except for chamber music where Franck and Fauré write late romantic sonatas, while Debussy is very innovative within a three movement sonata. Estampes, by Debussy, are taken in almost as an afterthought to illustrate the direction Debussy takes in his piano solo music. While Estampes is by definition a set of character pieces they function like a sonata with three movements.

Scatman

Scatman, aka Andreas Grassl, knew no fear when it came to verbal acrobatics. Burn - A List of my Enemies, his column in his Bavarian High School newspaper, run for five consecutive years, hitting his targets with caustic wit and irony. The list of enemies ranged from Bavarian farms (compulsory normality) to television companies (the rule of mediocrity) to Paris Hilton (trivia domination). Before graduating from high school, Scatman finished his last column with the following sentence: ‘Please tell me, what am I supposed to conjure up as a grandiose finale for the end of this five-year series?’