Search results for "reliability"
showing 10 items of 1563 documents
Surface, mechanical and barrier properties of bio-based composite films based on chitosan and whey protein
2014
Mono-component and composite bilayer and blend films composed of chitosan and whey protein were made. Colour, microstructure, water contact angles, swelling, water vapour sorption, barrier properties (oxygen, water vapour), water vapour diffusion coefficients and mechanical properties were determined. The influence of water vapour on barrier properties was studied in relation to the surface and structural properties. Mono-component and bilayer films were transparent with a homogeneous surface. Contrarily, blend films were translucent. Bilayer films had significantly lower water vapour permeability in comparison to mono-component and blend films. In all bilayer films, the air side (chitosan)…
Mechanical and barrier properties of extruded film made from sodium and calcium caseinates
2014
Abstract Over the past few years, much interest has been placed into the investigation of increased barrier and mechanical properties of protein films via a multitude of approaches. Generally, these techniques involve modifications of interactions among protein molecules, such as ionic crosslinking using divalent ions. To evaluate the crosslinking effect of Ca 2+ cations, films were made from calcium caseinate (CaCAS) and/or sodium caseinate (NaCAS). The production of caseinate thin films was carried out in two steps: first thermoplastic pellets were made using a co-rotating twin-screw extruder, then they were transformed into thin films (60 μm) using a classical film blowing machine. Tensi…
Self-Localization of Distributed Microphone Arrays Using Directional Statistics with DoA Estimation Reliability
2019
This paper addresses the problem of self-localization of distributed microphone arrays from microphone recordings by following a two-step optimization procedure. In the first step, the relative geometry of the sources and arrays is inferred by the proposed maximum likelihood estimator. It is derived under the assumption that the acquired unit-norm vectors pointing towards the unknown source positions follow a von Mises-Fisher distribution in a D-dimensional space. In the second step, the absolute positions and synchronization offsets between the arrays are estimated from the inferred relative geometry by using the Least Squares procedure. To improve the accuracy of the method, we propose as…
Middleware for transparent TCP connection migration : masking faulty TCP-based services
2004
Masteroppgave i informasjons- og kommunikasjonsteknologi 2004 - Høgskolen i Agder, Grimstad Mission critical TCP-based services create a demand for robust and fault tolerant TCP communication. Sense Intellifield monitors drill operations on rig sites offshore. Critical TCP-based services need to be available 24 hours, 7 days a week, and the service providers need to tolerate server failure. How to make TCP robust and fault tolerant without modifying existing infrastructure like existing client/server applications, services, TCP stacks, kernels, or operating systems is the motivation of this thesis. We present a new middleware approach, first of its kind, to allow TCP-based services to survi…
Assessing first-year engineering students' pre-university mathematics knowledge: preliminary validity results based on an item response theory model
2020
The importance of students’ prior knowledge to their current learning outcomes cannot be overemphasised. Students with adequate prior knowledge are better prepared for the current learning materials than those without the knowledge. However, assessment of engineering students' prior mathematics knowledge has been beset with a lack of uniformity in measuring instruments and inadequate validity studies. This study attempts to provide evidence of validity and reliability of a Norwegian national test of prior mathematics knowledge using an explanatory sequential mixed-methods approach. This approach involves use of an item response theory model followed by cognitive interviews of some students …
Safety Assurance of a High Voltage Controller for an Industrial Robotic System
2020
Abstract Due to the risk of discharge sparks and ignition, there are strict rules concerning the safety of high voltage electrostatic systems used in industrial painting robots. In order to assure that the system fulfils its safety requirements, formal verification is an important tool to supplement traditional testing and quality assurance procedures. The work in this paper presents formal verification of the most important safety functions of a high voltage controller. The controller has been modelled as a finite state machine, which was formally verified using two different model checking software tools; Simulink Design Verifier and RoboTool. Five safety critical properties were specifie…
Data Quality Model-based Testing of Information Systems: the Use-case of E-scooters
2020
The paper proposes a data quality model-based testing methodology aimed at improving testing methodology of information systems (IS) using previously proposed data quality model. The solution supposes creation of a description of the data to be processed by IS and the data quality requirements used for the development of the tests, followed by performing an automated test of the system on the generated tests verifying the correctness of data to be entered and stored in the database. The generation of tests for all possible data quality conditions creates a complete set of tests that verify the operation of the IS under all possible data quality conditions. The proposed solution is demonstra…
Attendibilità dei modelli per la valutazione dei moduli elastici delle murature suggeriti dalle norme tecniche
2012
In this paper the results of an experimental investigation aimed to the assessment of Young moduli, rigidity moduli and other mechanical properties for different types of masonry are shown. The mechanical characteristics predicted by models proposed by some technical codes were compared against experimental data. This study was motivated by the suggestion of the Masonry Standards Joint Committee's (MSJC) code that, while proposing the use of such models, acknowledges the lack of testing in support of their validation. The experimental investigation has included compressive tests on components (blocks and mortar), diagonal compressive tests and ordinary compressive tests (orthogonally to bed…
A comparison between dental measurements taken from CBCT models and those taken from a digital method.
2011
The aims of the study were to assess speed, reliability, accuracy, and reproducibility in measuring mesiodistal tooth sizes, bicanine widths, bimolar widths, and arch lengths (ALs) using cone beam computed tomography (CBCT) and to compare them with the same measurements obtained using a two-dimensional (2D) Digital Method. Plaster study models were made for 27 patients and then digitalized and measured using a 2D Digital Method. CBCTs were undertaken on the same 27 patients using the Dental Picasso Master 3D® and the images obtained were then analysed using the InVivoDental program. The correlation study of the two measuring methods, which were compared by determining the regression paramet…
Researches regarding cutting tool condition monitoring
2017
The paper main purpose is monitoring of tool wear in metal cutting using neural networks due to their ability of learning and adapting their self, based on experiments. Monitoring the cutting process is difficult to perform on-line because of the complexity of tool wear process, which is the most important parameter that defines the tool state at a certain moment. Most of the researches appraise the tool wear by indirect factors such as forces, consumed power, vibrations or the surface quality. In this case, it is important to combine many factors for increasing the accuracy of tool wear prediction and establish the admissible size of wear. For this, paper both the theoretical data obtained…