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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Validation of mappings between data schemas

Rull Fort, Guillem 19 January 2011 (has links)
En esta tesis, presentamos un nuevo enfoque para validar mappings entre esquemas de datos que permite al diseñador comprobar si el mapping satisface o no ciertas propiedades deseables. La respuesta que obtiene el diseñador no se limita a un simple valor booleano, sino que dependiendo del resultado de la comprobación obtendrá un ejemplo/contraejemplo que ilustre ese resultado, o bien se le indicará el conjunto de restricciones de integridad de los esquemas y formulas del mapping responsables de ese resultado. Una de las características principales de nuestro enfoque es que es capaz de tratar una clase muy expresiva de mappings y esquemas relacionales. En particular, nuestro enfoque es capaz de tratar con formulas de mapping consistentes en inclusiones y igualdades de consultas, además de permitir el uso de negaciones y comparaciones aritméticas tanto en las propias formulas del mapping como en las vistas definidas en los esquemas. Nuestro enfoque también permite tratar restricciones de integridad, las cuales pueden estar definidas no solo sobre las tablas sino también sobre las vistas de los esquemas. Dado que razonar sobre este tipo de mappings y esquemas es, desafortunadamente, indecidible, proponemos realizar un test de terminación previo a la validación del mapping. Si el test de terminación da una respuesta positiva, entonces podremos estar seguros de que la posterior comprobación de la propiedad deseable correspondiente terminará. Finalmente, también extendemos nuestro enfoque más allá del caso relacional y lo aplicamos al contexto de mappings entre esquemas XML. / In this thesis, we present a new approach to the validation of mappings between data schemas. It allows the designer to check whether the mapping satisfies certain desirable properties. The feedback that our approach provides to the designer is not only a Boolean answer, but either a (counter)example for the (un)satisfiability of the tested property, or the set of mapping assertions and schema constraints that are responsible for that (un)satisfiability. One of the main characteristics of our approach is that it is able to deal with a very expressive class of relational mapping scenarios; in particular, it is able to deal with mapping assertions in the form of query inclusions and query equalities, and it allows the use of negation and arithmetic comparisons in both the mapping assertions and the views of the schemas; it also allows for integrity constraints, which can be defined not only over the base relations but also in terms of the views. Since reasoning on the class of mapping scenarios that we consider is, unfortunately, undecidable, we propose to perform a termination test as a pre-validation step. If the answer of the test is positive, then checking the corresponding desirable property will terminate. We also go beyond the relational setting and study the application of our approach to the context of mappings between XML schemas.
322

Discrete event modelling and Simulation of an Assembly Line at GKN Driveline Köping AB

Yesilgul, Mustafa, Nasser, Firas January 2013 (has links)
Today’s economic conditions force companies and organizations to work more effectively in their processes due to different reasons.  Especially; after the Second World War, owing to the changing business perception and strong competition between companies, new terms such as productivity, flexible systems, efficiency, and lean came into industrial engineering discipline. However, these kinds of terms also brought a new question. How are they reached?  At that point, discrete event simulation has been used as an effective method to give an answer to this question. From this perspective; this project focuses on discrete event simulation and its role in real industrial processes. The main interest of this paper is discrete event simulation, but in this study we also tried to give some detailed information about other types of simulations such as continuous and discrete rate. Basically, we can say that this paper consists of several parts. In the beginning of this paper, the reader can find some theoretical information about simulation itself and the requirements for implementing it on real processes. Secondly, we tried to explain different types of simulations and the reason why we used discrete event simulation instead of continuous or discrete rate in our case study. Furthermore, one of the main areas of this research is to inform the reader about how computer support is used as a simulation tool by today’s companies. To do this, a powerful software, Extendsim8, is described in detail.  The reader is able to find all the information about how to create discrete event models in this software. In case study part, we are able to find the results of the five months work that we did between February and June at GKNDriveline Köping AB in Sweden. In these five months, we had been busy with analyzing an assembly line, collecting data, creating a simulation model, discussion with workers and engineers and doing some tests such as validation & verification. In this part, the reader can find all the information about the production line and the simulation model. In conclusion, reader can find the results of the project at the end with the visualization of future state. As it will be discussed repeatedly in the paper, validation is one of the important steps in a simulation project. Therefore, in order to see the reliability of our simulation model, different calculations and tests were made. Last of all, some of results will be shown by graphs and tables in order to give better insight to reader.
323

A Framework for Machine-Assisted Software Architecture Validation

Lichtner, Kurt January 2000 (has links)
In this thesis we propose a formal framework for specifying and validating properties of software system architectures. The framework is founded on a model of software architecture description languages (ADLs) and uses a theorem-proving based approach to formally and mechanically establish properties of architectures. Our approach allows models defined using existing ADLs to be validated against properties that may not be expressible using the original notation and tool-set. The central component of the framework is a conceptual model of architecture description languages. The model formalizes a salient, shared set of design categories, relationships and constraints that are fundamental to these notations. An advantage of an approach based on a conceptual model is that it provides a uniform view of design information across a selection of languages. This allows us to construct alternate formal representations of design information specified using existing ADLs. These representations can then be mechanically validated to ensure they meet their specific formal requirements. After defining the model we embed it in the logic of the PVS theorem-proving environment and illustrate its utility with a case study. We first demonstrate how the elements of a design are specified using the model, and then show how this representation is validated using machine-assisted proof. Our approach allows the correctness of a design to be established against a wide range of properties. We illustrate with structural properties, behavioural properties, relationships between the structural and behavioural specification, and dynamic, or evolving aspects of a system's topology.
324

Using Chemical Crosslinking and Mass Spectrometry for Protein Model Validation and Fold Recognition

Mak, Esther W. M. January 2006 (has links)
The 3D structures of proteins may provide important clues to their functions and roles in complex biological pathways. Traditional methods such as X-ray crystallography and NMR are not feasible for all proteins, while theoretical models are typically not validated by experimental data. This project investigates the use of chemical crosslinkers as an experimental means of validating these models. Five target proteins were successfully purified from yeast whole cell extract: Transketolase (TKL1), inorganic pyrophosphatase (IPP1), amidotransferase/cyclase HIS7, phosphoglycerate kinase (PGK1) and enolase (ENO1). These TAP-tagged target proteins from yeast <em>Saccharomyces cerevisiae</em> allowed the protein to be isolated in two affinity purification steps. Subsequent structural analysis used the homobifunctional chemical crosslinker BS<sup>3</sup> to join pairs of lysine residues on the surface of the purified protein via a flexible spacer arm. Mass spectrometry (MS) analysis of the crosslinked protein generated a set of mass values for crosslinked and non-crosslinked peptides, which was used to identify surface lysine residues in close proximity. The Automatic Spectrum Assignment Program was used to assign sequence information to the crosslinked peptides. This data provided inter-residue distance constraints that can be used to validate or refute theoretical protein structure models generated by structure prediction software such as SWISS-MODEL and RAPTOR. This approach was able to validate the structure models for four of the target proteins, TKL1, IPP1, HIS7 and ENO1. It also successfully selected the correct models for TKL1 and IPP1 from a protein model library and provided weak support for the HIS7, PGK1 and ENO1 models.
325

A Framework for Machine-Assisted Software Architecture Validation

Lichtner, Kurt January 2000 (has links)
In this thesis we propose a formal framework for specifying and validating properties of software system architectures. The framework is founded on a model of software architecture description languages (ADLs) and uses a theorem-proving based approach to formally and mechanically establish properties of architectures. Our approach allows models defined using existing ADLs to be validated against properties that may not be expressible using the original notation and tool-set. The central component of the framework is a conceptual model of architecture description languages. The model formalizes a salient, shared set of design categories, relationships and constraints that are fundamental to these notations. An advantage of an approach based on a conceptual model is that it provides a uniform view of design information across a selection of languages. This allows us to construct alternate formal representations of design information specified using existing ADLs. These representations can then be mechanically validated to ensure they meet their specific formal requirements. After defining the model we embed it in the logic of the PVS theorem-proving environment and illustrate its utility with a case study. We first demonstrate how the elements of a design are specified using the model, and then show how this representation is validated using machine-assisted proof. Our approach allows the correctness of a design to be established against a wide range of properties. We illustrate with structural properties, behavioural properties, relationships between the structural and behavioural specification, and dynamic, or evolving aspects of a system's topology.
326

Using Chemical Crosslinking and Mass Spectrometry for Protein Model Validation and Fold Recognition

Mak, Esther W. M. January 2006 (has links)
The 3D structures of proteins may provide important clues to their functions and roles in complex biological pathways. Traditional methods such as X-ray crystallography and NMR are not feasible for all proteins, while theoretical models are typically not validated by experimental data. This project investigates the use of chemical crosslinkers as an experimental means of validating these models. Five target proteins were successfully purified from yeast whole cell extract: Transketolase (TKL1), inorganic pyrophosphatase (IPP1), amidotransferase/cyclase HIS7, phosphoglycerate kinase (PGK1) and enolase (ENO1). These TAP-tagged target proteins from yeast <em>Saccharomyces cerevisiae</em> allowed the protein to be isolated in two affinity purification steps. Subsequent structural analysis used the homobifunctional chemical crosslinker BS<sup>3</sup> to join pairs of lysine residues on the surface of the purified protein via a flexible spacer arm. Mass spectrometry (MS) analysis of the crosslinked protein generated a set of mass values for crosslinked and non-crosslinked peptides, which was used to identify surface lysine residues in close proximity. The Automatic Spectrum Assignment Program was used to assign sequence information to the crosslinked peptides. This data provided inter-residue distance constraints that can be used to validate or refute theoretical protein structure models generated by structure prediction software such as SWISS-MODEL and RAPTOR. This approach was able to validate the structure models for four of the target proteins, TKL1, IPP1, HIS7 and ENO1. It also successfully selected the correct models for TKL1 and IPP1 from a protein model library and provided weak support for the HIS7, PGK1 and ENO1 models.
327

Validation of Volumetric Contact Dynamics Models

Boos, Michael January 2011 (has links)
A volumetric contact dynamics model has been proposed by Gonthier et al. [1, 2, 3] for the purpose of rapidly generating reliable simulations of space-based manipulator contact dynamics. By assuming materials behave as a Winkler elastic foundation model, forces and moments between two bodies in contact can be expressed in terms of the volume of interference between the undeformed geometries of the bodies. Friction between bodies is modelled by a dwell-time dependent bristle model for both tangential friction, and spinning friction torque. This volumetric model has a number of advantages. Unlike point-contact models, it allows for the modelling of contact between complex geometries and scenarios where the contact surface is relatively large, while being less computationally expensive than finite element methods. Rolling resistance is included in the model through damping effects across the volume of interference. The friction model accounts for dwell-time dependent slip-stick effects, spinning friction torque, and the Contensou effect. In this thesis, an experimental validation of the volumetric contact model is presented for the first time. Models for simple geometries in contact (e.g. cylinder-on-plane, sphere-on-plane) have been developed for stationary contact and for contact with motion normal and tangential to the contact surface. Tangential motion is modelled with pure translation, pure rotation about the normal axis, and combined motion, in order to separately consider friction forces, spinning friction torque, and the Contensou effect, respectively. An apparatus has been developed to experimentally validate these models for metal-on-metal contact. The apparatus has two configurations, one for validating the normal contact models and the other for the friction models. Experimental measurements of forces and displacements are used to identify model parameters (e.g. volumetric stiffness, friction coefficients, etc.). For normal force experiments, modelling the contact forces as proportional to volume of interference was found to be a reasonable approximation. A Hertzian model was compared with the volumetric model for spherical payloads loaded quasi-statically. Using stiffnesses estimated from spherical experiments, small misalignments of the cylindrical payloads were estimated that corresponded well with measured results. Dynamic experiments suggest an inverse relationship between impact velocity and the hysteretic damping coefficient. The high normal forces applied in the friction experiments were found to create significant wear on the contact surfaces. Coefficients of friction between titanium and aluminum were found to be consistent translationally and rotationally. Friction forces from combined translation and rotation demonstrate that the Contensou effect is accurately described by the volumetric contact model.
328

Evaluating Clusterings by Estimating Clarity

Whissell, John January 2012 (has links)
In this thesis I examine clustering evaluation, with a subfocus on text clusterings specifically. The principal work of this thesis is the development, analysis, and testing of a new internal clustering quality measure called informativeness. I begin by reviewing clustering in general. I then review current clustering quality measures, accompanying this with an in-depth discussion of many of the important properties one needs to understand about such measures. This is followed by extensive document clustering experiments that show problems with standard clustering evaluation practices. I then develop informativeness, my new internal clustering quality measure for estimating the clarity of clusterings. I show that informativeness, which uses classification accuracy as a proxy for human assessment of clusterings, is both theoretically sensible and works empirically. I present a generalization of informativeness that leverages external clustering quality measures. I also show its use in a realistic application: email spam filtering. I show that informativeness can be used to select clusterings which lead to superior spam filters when few true labels are available. I conclude this thesis with a discussion of clustering evaluation in general, informativeness, and the directions I believe clustering evaluation research should take in the future.
329

Identification and validation of genomic regions associated with pre-harvest sprouting resistance in white-grained wheat (<i>triticum aestivum</i> L.)

Singh, Rajender 31 January 2008 (has links)
Pre-harvest sprouting (PHS) in bread wheat (<i>Triticum aestivum</i> L.) is one of the major abiotic constraints influencing the production of high quality grain. The flour milled from sprouted wheat grains has increased Ñ-amylase activity as compared to non-sprouted grain. PHS negatively affects the properties of flour with deleterious effects on bread and noodle quality. White-grained wheat is generally more susceptible to PHS damage than red-grained wheat. The objectives of this study were to identify a suitable method for phenotyping PHS resistance and to identify PHS resistance genomic regions and markers that could be used for marker-assisted selection in wheat improvement programs. A doubled haploid (DH) mapping population from a cross between two white-grained spring wheat genotypes, Argent (non-dormant) and W98616 (dormant) was used in this study. Forty DH lines (20 dormant and 20 non-dormant) were evaluated for germination frequency, Falling Number, and Ñ-amylase activity in dry and water-imbibed seeds and spikes. The germination test was the most reliable method for measurement of PHS resistance, whereas the Falling Number and Ñ-amylase activity in dry harvested seeds could not be correlated to dormancy levels. However, a positive association (r = 0.60***) was detected between germination frequency and Ñ-amylase activity in imbibed seeds. To identify the genomic regions associated with PHS resistance, a genetic linkage map with a total genome coverage of 2,577 cM was developed. The map was constructed from 913 scored markers (356 SSR, 290 AFLP, 258 DArT and 9 EST) with an average marker density of 3.7 cM/marker. Five genomic regions on chromosomes 1A, 3A, 4A, 7A and 7D were associated with PHS resistance by interval mapping and all regions were contributed by the dormant parent W98616. A total of 60 Canadian wheat cultivars and experimental lines were screened with three SSR markers, DuPw004, barc170 and wmc650, located under the major quantitative trait locus (QTL) on chromosome 4A. The SSR markers explained 60-75% of the total variation in germination frequency among different wheat genotypes. By using the DuPw004 marker in marker-assisted back crossing, the population size in the BC1F1 and BC2F1 generations were reduced by 41% and 59%, respectively. Thus, the 4A QTL markers have been proven useful for marker-assisted selection of PHS resistance for wheat improvement.
330

Heat and moisture transfer in a bed of gypsum boards

James, Christopher M 04 May 2009 (has links)
Several recent projects in building science have examined the hygric performance of building materials. Most building materials adsorb from and desorb water vapour to their environments. This phenomenon could be used to help control relative humidity fluctuations in buildings, experienced during periods of moisture production such as cooking, washing or bathing. They could also be used to reduce the need for mechanical ventilation and air conditioning to remove excess moisture. To understand how a building material responds to transient changes in relative humidity, testing is required.<p> This thesis outlines the testing performed on gypsum board, a common wall and ceiling finishing material used inside buildings. The effect of paint coatings on the gypsum boards and heat and mass transfer coefficients of the air passing over the gypsum bed was tested. The data produced from these experiments was used to validate several numerical models through an International Energy Agency/Energy Conservation in Buildings and Community Systems (IEA/ECBCS), Annex 41: Whole Building Heat, Air and Moisture Response. The validated models are important for simulating the process of adsorption and desorption in building materials to predict failure in the building envelope and expected indoor air conditions.<p> A sensitivity analysis is also presented which examines the effects of the sorption isotherm and vapour permeability of the gypsum and paints as well as the heat and mass transfer coefficients the boards are exposed to. The sensitivity range used was determined from the tests performed on the gypsum boards and paints which were also performed during the work of Annex 41.<p> The results of this thesis produced a high quality data which can also be used to validate future numerical models. All information required for validation of future models is available such as dimensions of test section, test conditions, material properties and the experimental data.<p> The results show that when designing for passive humidity control in buildings using gypsum boards, the most influential factor is the type of coating or paint applied to the surface. The sensitivity analysis showed that material properties such as vapour permeability and the sorption isotherms, for the expected temperature range, should be well known for increased accuracy of the simulation. The material properties were determined from inter-laboratory testing at 14 different institutions to achieve confident values.<p> The effect of increasing the heat and mass transfer coefficients, over the range of coefficients studied in this thesis, showed negligible differences in the results. The simulated results had very good agreement between the models and were mostly within experimental uncertainty of the measurements.

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