48 research outputs found
Possibilities and Limitations of Automatic Feature Extraction shown by the Example of Crack Detection in 3D-CT Images of Concrete Specimen
No full textTo assess the influence of the alkali-silica reaction (ASR) on pavement concrete 3D-CT imaging has been applied to concrete samples. Prior to imaging these samples have been drilled out of a concrete beam pre-damaged by fatigue loading. The resulting high resolution 3D-CT images consist of several gigabytes of voxels. Current desktop computers can visualize such big datasets without problems but a visual inspection or manual segmentation of features such as cracks by experts can only be carried out on a few slices. A quantitative analysis of cracks requires a segmentation of the whole specimen which could only be done by an automatic feature detection. This arises the question of the reliability of an automatic crack detection algorithm, its certainty and limitations. Does the algorithm find all cracks? Does it find too many cracks? Can parameters of that algorithm, once identified as good, be applied to other samples as well? Can ensemble computing with many crack parameters overcome the difficulties with parameter finding? By means of a crack detection algorithm based on shape recognition (template matching) these questions will be discussed. Since the author has no access to reliable ground truth data of cracks the assessment of the certainty of the automatic crack is restricted to visual inspection by experts. Therefore, an artificial dataset based on a combination of manually segmented cracks processed together with simple image processing algorithms is used to quantify the accuracy of the crack detection algorithm. Part of the evaluation of cracks in concrete samples is the knowledge of the surrounding material. The surrounding material can be used to assess the detected cracks, e.g. micro-cracks within the aggregate-matrix interface may be starting points for cracks on a macro scale. Furthermore, the knowledge of the surrounding material can help to find better parameter sets for the crack detection itself because crack characteristics may vary depending on their surrounding material. Therefore, in addition to a crack detection a complete segmentation of the sample into the components of concrete, such as aggregates, cement matrix and pores is needed. Since such a segmentation task cannot be done manually due to the amount of data, an approach utilizing convolutional neuronal networks stemming from a medical application has been applied. The learning phase requires a ground truth i.e. a segmentation of the components. This has to be created manually in a time-consuming task. However, this segmentation can be used for a quantitative evaluation of the automatic segmentation afterwards. Even though that work has been performed as a short term subtask of a bigger project funded by the German Research Foundation (DFG) this paper discusses problems which may arise in similar projects, too.
[1.2MB | id=23664 ]
iCT 2019
Session: Short talks
Thu 13:50 Auditorium 2019-03
Möglichkeiten und Grenzen automatischer Merkmalserkennung am Beispiel von Risserkennungen in 3D-CT-Aufnahmen von Betonproben
O. Paetsch11
Visualisation and Data Analysis; Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
Abstract
[1MB | id=23104 ] DE
DGZfP 2018
Session: Bauwesen 2018-09
Quantitative Rissanalyse im Fahrbahndeckenbeton mit der 3D-Computertomographie
D. Meinel125, K. Ehrig128, F. Weise16, O. Paetsch211
1Division 8.5; BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany
2Visualisation and Data Analysis; Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
concrete, ROI tomography, in-situ-CT, 3D-CT, Beton, AKR, Feuchtetransport, automatic crack detection
Abstract
[0.7MB | id=18980 ] DE
DGZfP 2015
Session: CT Algorithmen 2016-04
3D Corrosion Detection in Time-dependent CT Images of Concrete
O. Paetsch111, D. Baum15, S. Prohaska17, K. Ehrig228, D. Meinel225, G. Ebell24
1Visualisation and Data Analysis; Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
2Division 8.5; BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany
CT, multi-angle radiography, defect detection, Feature Extraction, image processing, concrete, corrosion
Abstract
[0.5MB | id=18043 ]
DIR 2015
Session: Quantitative imaging and image processing 2015-08
Korrosionsverfolgung in 3D-computertomographischen Aufnahmen von Stahlbetonproben
O. Paetsch111, D. Baum15, G. Ebell24, K. Ehrig228, A. Heyn2, D. Meinel225, S. Prohaska17
1Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
2Division VIII.3; BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany
Computertomographie [0.4MB | id=17375 ] DE
DGZfP 2014
Session: Bauwesen 2015-03
Examination of Damage Processes in Concrete with CT
D. Meinel125, K. Ehrig128, V. L’Hostis2, B. Muzeau2, O. Paetsch311
1BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany
2Laboratoire d’Etude du Comportement des Bétons et des Argiles; Commissariat Energie Atomique (CEA)287, Gif-Sur-Yvette, France
3Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
X-ray computed tomography, concrete, corrosion, crack detection, 3D visualization
Abstract
[4.9MB | id=15692 ]
iCT 2014
Session: Non-destructive Testing and 3D Materials Characterisation of... 2014-06
3-D-Visualisierung und statistische Analyse von Rissen in mit Computer-Tomographie untersuchten Betonproben
O. Paetsch111, D. Baum15, D. Breßler1, K. Ehrig228, D. Meinel225, S. Prohaska1,17
1Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
2Division VIII.3; BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany
Radiographic Testing (RT), statistical analysis, 3D Computed Tomography, visualization, concrete structural damage, automated crack detection [1MB | id=15343 ] DE
DGZfP 2013
Session: Computertomographie 2014-03
Vergleich automatischer 3D-Risserkennungsmethoden für die quantitative Analyse der Schadensentwicklung in Betonproben mit Computertomographie
O. Paetsch111, K. Ehrig228, D. Meinel225, D. Baum15, S. Prohaska1,1,17
1Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
2Division VIII.3; BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany
Radiographic Testing (RT), visualization, crack detection, Visualisierung, computer tomography, template matching, Hessian eigenvalues, ZIBAmira, automated crack detection, percolation [0.9MB | id=14269 ] DE
DGZfP 2012
Session: Computertomographie 2013-05
Automated 3D Crack Detection for Analyzing Damage Processes in Concrete with Computed Tomography
O. Paetsch111, D. Baum15, K. Ehrig228, D. Meinel225, S. Prohaska1,1,17
1Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
2Division VIII.3; BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany
computed tomography, template matching, Hessian eigenvalues, crack statistics, visualization, crack surface, ZIBAmira [0.6MB | id=13736 ]
iCT 2012
Session: Poster - Analysis and Algorithms 2012-12
3-D-Visualisierung von Radar- und Ultraschallecho-Daten mit ZIBAmira
D. Streicher112, O. Paetsch211, R. Seiler2, S. Prohaska27, M. Krause360 [Profile of Krause] , C. Boller178
1Saarland University74, Saarbrücken, Germany
2Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany
3BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany [0.4MB | id=12284 ] DE
DGZfP 2011
Session: Bauwesen 2012-05
Comparison of Crack Detection Methods for Analyzing Damage Processes in Concrete with Computed Tomography
K. Ehrig128, J. Goebbels153, D. Meinel125, O. Paetsch211, S. Prohaska27, V. Zobel2
1Division VIII.3; BAM Federal Institute for Materials Research and Testing1277, Berlin, Germany
2Konrad-Zuse-Institut Berlin (ZIB)18, Berlin, Germany [0.7MB | id=11150 ]
DIR 2011
Session: Poster 2011-11
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2019 Oct 7-9
11th International Symposium on NDT in Aerospace 2019
2019 Nov 13-15
3rd Singapore International NDT Conference & Exhibition, SINCE 2019
2019 Dec 4-5
10th Conference on Industrial Computed Tomography (iCT) 2020
2020 Feb 4-7
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2020 Sep 9-11
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Static permittivity of environmentally relevant low-concentration aqueous solutions of NaCl, NaNO3, and Na2SO4
No full textIn this paper, the result of a systematic study and molecular mechanisms governing the dielectric spectra of aqueous solutions of NaCl, NaNO3, and Na2SO4 with environmentally relevant concentrations (∼mmol/l) are presented, for frequencies from 200 MHz up to 20 GHz and at temperature 25.00 ± 0.01 °C. The measured spectra were fitted with a Debye relaxation model using a non-linear, weighted, least-squares analysis. Conductivity was measured independently to reduce uncertainty in obtaining other parameters by spectral fitting. Careful experimentation provided dielectric data of sufficiently low uncertainty to enable observation of polarization mechanisms that emerge only in the low-concentration regime. The data were fitted by a concentration-dependent parametric model that includes terms accounting for internal depolarizing fields and the solvent dilution effect (mixture relation), the kinetic depolarization effect, the dielectric saturation effect, and the Debye–Falkenhagen effect that accounts for the contribution of ionic atmosphere polarization. It has been shown that, in NaCl and NaNO3 solutions at sufficiently low concentrations, the static permittivity increases due to the Debye–Falkenhagen effect. It has also been shown that, to calculate the number of irrotationally bound water molecules ZIB, the measured static permittivity values should be corrected to account for the contributions of kinetic depolarization and Debye–Falkenhagen effects. Otherwise, unrealistic values of ZIB are obtained. An explanation for the different strengths of the Debye–Falkenhagen effect observed for the different electrolyte solutions, essentially due to the electrophoretic effect and coordination number, is also presented.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Gorji, Amin, and Nicola Bowler. "Static permittivity of environmentally relevant low-concentration aqueous solutions of NaCl, NaNO3, and Na2SO4." The Journal of Chemical Physics 153, no. 1 (2020): 014503 and may be found at DOI: 10.1063/1.5144301. Posted with permission.</p
Comparative Visual Analysis of Structure-Performance Relations in Complex Bulk-Heterojunction Morphologies
No full textThe structure of Bulk-Heterojunction (BHJ) materials, the main component of organic photovoltaic solar cells, is very complex, and the relationship between structure and performance is still largely an open question. Overall, there is a wide spectrum of fabrication configurations resulting in different BHJ morphologies and correspondingly different performances. Current state-of-the-art methods for assessing the performance of BHJ morphologies are either based on global quantification of morphological features or simply on visual inspection of the morphology based on experimental imaging. This makes finding optimal BHJ structures very challenging. Moreover, finding the optimal fabrication parameters to get an optimal structure is still an open question. In this paper, we propose a visual analysis framework to help answer these questions through comparative visualization and parameter space exploration for local morphology features. With our approach, we enable scientists to explore multivariate correlations between local features and performance indicators of BHJ morphologies. Our framework is built on shape-based clustering of local cubical regions of the morphology that we call patches. This enables correlating the features of clusters with intuition-based performance indicators computed from geometrical and topological features of charge paths.This work was supported in part by King Abdullah University of Science and Technology (KAUST). The fourth author was supported in part by KAUST Global Collaborative Research: CRG-1-2012-THO-015-ISU, and by the Center for Computational Research at the University at Buffalo
The role of fiscal policy in inertially inflated Argentina
No full textInflation has been the dominant economic variable in Latin American during the 1980's. Moreover, it is generally accepted that fiscal imbalance is the ultimate source of price instability. This dissertation provides a game-theoretic model of the social conflict theory of inflation and creates cyclical indices of fiscal stance for developing countries suffering from inertial inflation.In the first essay we create an index of fiscal stance for inertially inflated economies. A zero inflation borrowing requirement (ZIB) is introduced which corrects deficit figures for the inflationary component of interest payments, and the inflationary erosion of tax revenue (the Olivera-Tanzi effect). The ZIB is applied to Argentine data in order to evaluate the claim that the Argentine deficit is inflation-induced, rather than due to structural or policy shortcomings.In the second essay a game-theoretic model is presented which formalizes the role of deficits in the conflict theory of inflation. The game strikes a balance between orthodox and structural theories of inflation. In it, the Central Government is endogenous, and special interests are unable to form the coalitions necessary to temper their combined fiscal demands. Moreover, the game provides a natural framework for analyzing the criteria for successful implementation of the type of heterodox stabilization policies employed in Latin America in the 1980's.The third essay is an initial investigation into indices of fiscal stance which are consistent with the social conflict theory of inflation. Estimates are made for a hybrid of the cyclically neutral budget which reflects a macroeconomic target of income maintenance, rather than output gap minimization. The results suggest that Argentine fiscal stance has been tighter than previously believed."Taken together, the three essays reinforce the view that when inflation is a function of social conflict, standard or ""orthodox"" approaches to stabilization may be fatally flawed because the link between deficits and inflation is shown to be weak and/or misunderstood. Stabilization in a conflict society requires a mechanism to reduce social tensions through a legitimate system of distributing income shares, inflationary costs, and the costs of allocative efficiency."Made available in DSpace on 2011-05-07T14:03:55Z (GMT). No. of bitstreams: 2
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Author Correction: A shared neural basis underlying psychiatric comorbidity
No full textCorrection to: Nature Medicine. Published online 24 April 2023. In the version of this article initially published, the STRATIFY data also included cohort data from the ESTRA consortium, though this was not acknowledged in the author list and the section in Methods on the Stratify dataset. The Methods are now updated, and the author list is amended to combine the STRATIFY and ESTRA consortium names and to include the following authors: Marina Bobou, M. John Broulidakis, Betteke Maria van Noort, Zuo Zhang, Lauren Robinson, Nilakshi Vaidya, Jeanne Winterer, Yuning Zhang, Sinead King, Hervé Lemaître, Ulrike Schmidt, Julia Sinclair, Argyris Stringaris and Sylvane Desrivières. The STRATIFY and ESTRA consortia are now combined to list Marina Bobou, M. John Broulidakis, Betteke Maria van Noort, Zuo Zhang, Lauren Robinson, Nilakshi Vaidya, Jeanne Winterer, Yuning Zhang, Sinead King, Gareth J. Barker, Arun L. W. Bokde, Hervé Lemaître, Frauke Nees, Dimitri Papadopoulos Orfanos, Ulrike Schmidt, Julia Sinclair, Argyris Stringaris, Henrik Walter, Robert Whelan, Sylvane Desrivières and Gunter Schumann as members, and the IMAGEN consortium is updated to also include Sylvane Desrivières. Affiliations, author contributions and acknowledgements have been updated to reflect the new authorship, and all changes have been made in the HTML and PDF versions of the article
What is Zepey in Dubrovnik Monuments?
No full textGodine 1235. u Dubrovniku Velo i Malo vijeće izdaju zakon protiv raskoši i nekih običaja o svatovima, očito već preživjelih u urbanoj sredini ovoga grada. U ovoj Ordo de dotibus et nuptiis dva puta spominje se predmet s nazivom zepeya. Izdavači dubrovačkoga Statuta ovaj naziv tumače prema Du Cangeu kao orale mulierum, velum capitis, dakle kao pokrivalo ženske glave, prevjes ili veo. Ipak, ne može nas zadovoljiti ovako općenito razjašnjenje naziva zepeya, jer po svemu, upravo iz ovog najranijeg spomena u našim pisanim spomenicima, proizlazi da je zepeya neki osobit prevjes ili veo.Out the documents in Dubrovnik archives from 1235 and after that and out of the records in neighbouring Appulia the author explains the meaning, the form and the function of that womans veil which is called in Dubrovnik zepeya and in Appulia zeppa, zippa.
It is the wedding veil used by the bride. This veil is a distinguished one among the other women’s coverings for the head because it is precious, made of silk, decorated with a pearl and golden embroidery. The author thinks that this is the Persian word »zeb, zib« with the adjectival meaning »excellent, wonderful«. This elegant textile is not only the veil for the Bizantine women but is also a decorative handkerchief used with a gala dress in the hand or stuck into the belt. It is also used from the 6th century. It can be found in the iconograpy of Madona where it makes the bright motif, on the dark material (maforija).
Later in Dubrovnik in the 16th century there is a decorative handkerchief in the graph çippi.
The last pattern of the medieval Zepey we could see on the folk textile in Dubrovnik district. It is called »golden covering« which is used in Konavle for the bride veil. The last chosen examles are held in the museums. The author shows one of the most beautiful as an illustration for his work
TNC Expansion from 1990 to 2013
No full textThe paper traces the expansion of transnational corporations (TNC), with a particular focus on their foreign subsidiaries, economic position and the key sectors in which they were involved from 1990 to 2013. The author asks three fundamental questions: 1) What significant changes occurred in the process of TNC expansion during this period? 2) Is the importance of TNCs from developing and transition economies growing? 3) What are the future prospects of TNC development in the global economy? The paper is the result of a study of literature on the topic and UNCTAD statistical data. The author formulates a thesis that the role of TNCs from developing and transition economies in foreign direct investment (FDI) has grown since the 1990 s, while the proportion of TNCs from developed countries has shrunk. This testifies to the growing investment power of corporations from developing and transition economies, and it also means that global competition will increase in the future, the author says. According to the author, the main conclusions from the conducted analysis are as follows: 1) TNC expansion is intensifying, as reflected by an increased number of corporations and their subsidiaries abroad as well as their stronger economic position; 2) TNC from developing and transition economies play an increasing role in foreign investment; 3) In 2011, the value of FDI inflows to developed countries equalled that of FDI inflows to developing and transition countries; 4) Over the past decade, TNCs from Asia, especially China, have participated in many mergers and takeovers, achieving a positive net balance of acquisitions (versus the net balance of sales posted by corporations from developed countries such as the United States, Britain and Germany); 5) It is anticipated that global competition between TNCs will escalate because corporations from developing and transition countries aspire to maintain their fast-growing potential, while corporations from developed countries are seeking to regain their pre-crisis growth dynamics.Celem artykułu jest przedstawienie ekspansji korporacji transnarodowych (KTN), z uwzględnieniem liczby filii zagranicznych i ich pozycji ekonomicznej oraz zidentyfikowanie kluczowych sektorów zainteresowania w latach 1990–2013. Postawiono trzy zasadnicze pytania: 1) jakie ważniejsze zmiany nastąpiły w ekspansji KTN? 2) czy rośnie znaczenie KTN z krajów rozwijających się i krajów transformacji gospodarczej, a jeśli tak, to z jakich regionów? oraz 3) jakie są dalsze perspektywy rozwoju KTN w gospodarce światowej? Tekst powstał głównie na podstawie analizy literatury przedmiotu oraz danych statystycznych UNCTAD. Sformułowano tezę, iż od lat 90. XX w. rośnie udział KTN z krajów rozwijających się i krajów transformacji w zagranicznych inwestycjach bezpośrednich (ZIB), wobec jego spadku ze strony krajów rozwiniętych. Świadczy to o wzroście siły inwestycyjnej korporacji wywodzących się z tych państw, a w przyszłości oznaczać będzie wzrost konkurencji globalnej. Główne wioski z przeprowadzonej analizy są następujące: 1) nastąpił wzrost ekspansji KTN, zauważalny we wzroście liczby koncernów i ich filii za granicą oraz pozycji ekonomicznej, 2) wzrósł udział KTN z krajów rozwijających się i krajów transformacji w inwestycjach realizowanych za granicą, 3) w 2011 r. doszło do zrównania wartości napływu strumieni ZIB na rynki krajów rozwiniętych z napływem na rynki krajów rozwijających się i krajów transformacji, 4) w ostatniej dekadzie, KTN z regionu Azji (Chin) uczestniczą w fuzjach i przejęciach, osiągając dodatnie salda nabycia netto, wobec sald sprzedaży netto wykonywanych przez korporacje ze strony krajów rozwiniętych (USA, Wielka Brytania czy Niemcy), 5) przewiduje się, że nastąpi spotęgowanie konkurencji globalnej pomiędzy KTN, ze względu na chęć „utrzymania” szybkiego wzrostu potencjału korporacji z krajów rozwijających się i krajów transformacji, wobec chęci „odzyskania” dynamiki wzrostu sprzed kryzysu finansowego przez korporacje z krajów rozwiniętych
A package on formal power series.
No full textFormal Laurent-Puiseux series of the form are important in many branches of mathematics. Whereas {\sc Mathematica} supports the calculation of truncated series with its {\tt Series} command, and the {\sc Mathematica} package {\tt SymbolicSum} that is shipped with {\sc Mathematica} version 2 is able to convert formal series of the type mentioned above in some instances to their corresponding generating functions, in six publications of the author we developed an algorithmic procedure to do these conversions that is implemented by the author, A.\ Rennoch and G.\ Stölting in the {\sc Mathematica} package {\tt PowerSeries}. The implementation enables the user to reproduce most of the results of the extensive bibliography on series of Hansen, E.\ R.: A table of series and products. Prentice-Hall, 1975. Moreover a subalgorithm of its own significance generates differential equations satisfied by the input function
Determining the material parameters for the reconstruction of defects in carbon fiber reinforced polymers from data measured by flash thermography
No full textFlash thermography is a fast and reliable non-destructive testing method for the investigation of defects in carbon fiber reinforced polymer (CFRP) materials. In this paper numerical simulations of transient thermography data are presented, calculated for a quasi-isotropic flat bottom hole sample. They are compared to experimental data. These simulations are one important step towards the quantitative reconstruction of a flaw by assessing thermographic data. The applied numerical model is based on the finite-element method, extended by a semi-analytical treatment of the boundary of the sample, which is heated by the flash light. A crucial part for a reliable numerical model is the prior determination of the material parameters of the specimen as well as of the experimental parameters of the set-up. The material parameters in plane and in depth diffusivity are measured using laser line excitation. In addition, the absorption and heat transfer process of the first layers is investigated using an IR microscopic lens. The performance of the two distinct components of CFRP during heating – epoxy resin and carbon fibers – is examined. Finally, the material parameters are optimized by variation and comparison of the simulation results to the experimental data. The optimized parameters are compared to the measured ones and further methods to ensure precise material parameter measurements are discussed
