Search results for " Reliability"
showing 10 items of 557 documents
Copy–Move Forgery Detection by Matching Triangles of Keypoints
2015
Copy-move forgery is one of the most common types of tampering for digital images. Detection methods generally use block-matching approaches, which first divide the image into overlapping blocks and then extract and compare features to find similar ones, or point-based approaches, in which relevant keypoints are extracted and matched to each other to find similar areas. In this paper, we present a very novel hybrid approach, which compares triangles rather than blocks, or single points. Interest points are extracted from the image, and objects are modeled as a set of connected triangles built onto these points. Triangles are matched according to their shapes (inner angles), their content (c…
A Validation Study of Classroom Assessment Scoring System–Secondary in the Finnish School Context
2017
This study examined the reliability and validity of the Classroom Assessment Scoring System–Secondary (CLASS-S) in Finnish classrooms. Trained observers coded classroom interactions based on video recordings of 46 Grade 6 classrooms (450 cycles). Concurrent associations were investigated with respect to teacher self-ratings (e.g., efficacy beliefs and teaching-related stress). Confirmatory factor analysis showed that the hypothesized three-factor structure of the original CLASS-S (Emotional Support, Organizational Support, and Instructional Support), with some modifications, provided a better fit for the data compared with one- and two-factor structures. Structural validity was demonstrate…
State Model of Service Reliability
2006
We propose a simple formalism for modelling of a service reliability. A service is defined as an ordered set of states of a modelled application. In the model, a certain reliability is assigned to each application state. Reliability of a service is expressed in terms of above partial reliabilities.
Utilisation of barium-modified analcime in sulphate removal: Isotherms, kinetics and thermodynamics studies
2017
Abstract Analcime and commercial zeolite were employed as a precursor for preparing sorbent material for SO42− removal over barium modification. Three sorbents were prepared: barium-modified analcime (ANA-Na-Ba), barium-modified acid-washed analcime (ANA-Ac-Na-Ba) and barium-modified zeolite (ZSM5-Na-Ba). Of the prepared materials, ANA-Ac-Na-Ba was the most efficient sorbent material for SO42− removal, with a maximum sorption uptake of 13.7 mg g−1 at room temperature. Batch sorption experiments were performed to evaluate the effect of initial pH, initial SO42− concentration, sorbent dosage, temperature and contact time of sorption. Several isotherms were applied to describe the experimental…
Sound and reusable components for abstract interpretation
2019
Abstract interpretation is a methodology for defining sound static analysis. Yet, building sound static analyses for modern programming languages is difficult, because these static analyses need to combine sophisticated abstractions for values, environments, stores, etc. However, static analyses often tightly couple these abstractions in the implementation, which not only complicates the implementation, but also makes it hard to decide which parts of the analyses can be proven sound independently from each other. Furthermore, this coupling makes it hard to combine soundness lemmas for parts of the analysis to a soundness proof of the complete analysis. To solve this problem, we propose to c…
Probabilistic analysis of truss structures with uncertain parameters (virtual distortion method approach)
2004
A new approach for probabilistic characterization of linear elastic redundant trusses with uncertainty on the various members subjected to deterministic loads acting on the nodes of the structure is presented. The method is based on the simple observation that variations of structural parameters are equivalent to superimposed strains on a reference structure depending on the axial forces on the elastic modulus of the original structure as well as on the uncertainty (virtual distortion method approach). Superposition principle may be applied to separate contribution to mechanical response due to external loads and parameter variations. Statically determinate trusses dealt with the proposed m…
Dynamic behaviour of cracked granite and marble columns retrofitted with steel collars
2014
Marble and heavy stone columns are widely diffused in ancient churches and historical buildings in all the Mediterranean area. Their good mechanical properties allowed carrying great load values, while their bright colours and aesthetical characteristics have been used by a lot of ancient architects to achieve structural solutions with great visual impact. Despite their good compressive strength, marble columns could be damaged from environmental effects (e.g. longterm effects or thermal loads), which could crack the structural members. In this way, the slenderness of the column increases drastically and the presence of an imposed ground shaking could be critical, since the column will be m…
Digital generation of multivariate wind field processes
2001
Abstract A very efficient procedure for the generation of multivariate wind velocity stochastic processes by wave superposition as well as autoregressive time series is proposed in this paper. The procedure starts by decomposing the wind velocity field into a summation of fully coherent independent vector processes using the frequency dependent eigenvectors of the Power Spectral Density matrix. It is shown that the application of the method allows to show some very interesting physical properties that allow to reduce drastically the computational effort. Moreover, using a standard finite element procedure for approximating the frequency dependent eigenvectors, the generation procedure requi…
Competition between the buckling-driven delamination and wrinkling in compressed thin coatings
2012
Abstract The competition between two common failure modes of a thin coating under in-plane compression, the surface wrinkling and the buckling-driven delamination, is studied to assess the critical strain when the mechanical instability may occur at given geometrical and material parameters. A buckling map is constructed based on results of a finite element analysis, which relates the critical applied strain for the onset of instability to the interface adhesion and elastic properties of materials. An approximate scaling relation is derived for the energy release rate of buckling-driven delamination of a coating deposited on a compliant substrate.
Some consistency issues in multi-criteria decision making
2017
The complexity of decision-making problems included under the multi-criteria decision-making (MCDM) paradigm has favored the proliferation of many schools of thought and varied methodologies. It has not yet been possible to prove the supremacy of any of these approaches. Moreover, in some cases it is difficult to combine the theoretical validity of the approximations with their practical appropriateness. It seems that rigor and applicability are two opposing concepts, something that should not be so. It is our responsibility to bridge the gap. To reduce the gap between theory and practice and use effective methodological approaches, it is necessary to combine the rigor and objectivity of tr…