Search results for " Reliability."
showing 10 items of 551 documents
Human reliability analysis to support the development of a software project
2017
The Human Reliability Analysis (HRA) is considered as a useful tool in predicting and quantifying the occurrence of human errors during the execution of a specific task. With this recognition, the present paper firstly aims at discussing the support given by HRA methodologies to the fault risk evaluation. Then, the Technique for Human Error Rate Prediction (THERP) is suggested to evaluate the success probability of a software development project.
Maintenance Planning For The Reliability Maximization In A Large System With Vagueness In The Reliability Values Of Some Components
2015
This paper tackles the problem to single out the maintenance actions to be executed on a production system during the planned stop of given length. In detail, from a reliability viewpoint the system is assimilated as a series-parallel multi-component system and the maintenance actions need to maximize the system reliability up to the next planned stop. Moreover, it is assumed that some components reliability values are affected by vagueness within a given range. To solve the considered problem, an exact dynamic programming algorithm suitable to quickly point out the maintenance scheduling is developed and, moreover, it is formulated a proper parameter able to express the robustness of the o…
Reliability and Fabrication of Molds for Nanoimprinting
2010
During the last decade there has been a growing attention to nanoscaled materials and to the related technologies to produce them. The problems to overcome in the manufacturing of these kinds of items increase dramatically on decreasing the dimension of the devices. In this sense, the scientific research has been strongly stimulated to try to improve and optimize all the critical issues. One of the most attractive fields in nanomanufacturing is related to nanoimprinting, i.e. to the possibility to transfer a nanoscaled pattern from a mold to another substrate. In this technology, among the others, there are two main critical steps: the preparation of a good mold and the use of a correct rel…
Prnu Pattern Alignment for Images and Videos Based on Scene Content
2019
This paper proposes a novel approach for registering the PRNU pattern between different camera acquisition modes by relying on the imaged scene content. First, images are aligned by establishing correspondences between local descriptors: The result can then optionally be refined by maximizing the PRNU correlation. Comparative evaluations show that this approach outperforms those based on brute-force and particle swarm optimization in terms of reliability, accuracy and speed. The proposed scene-based approach for PRNU pattern alignment is suitable for video source identification in multimedia forensics applications.
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…