Добірка наукової літератури з теми "Automated Modal Analysis"

The modern engineering design process includes computer software packages that require approximations to be made when representing geometries. These approximations lead to inherent discrepancies between the design geometry of a part or assembly and the corresponding manufactured geometry. Further approximations are made during the analysis portion of the design process. Manufacturing defects can also occur, which increase the discrepancies between the design and manufactured geometry. These approximations combined with manufacturing defects lead to discrepancies which, for high precision parts, such as jet engine compressor blades, can affect the modal analysis results. In order to account for the manufacturing defects during analysis, mesh morphing is used to morph a structural finite element analysis mesh to match the geometry of compressor blades with simulated manufacturing defects. The mesh morphing process is improved by providing a novel method to convert heteromorphic shape matching within Sculptor to homeomorphic shape matching. This novel method is automated using Java and the NX API. The heteromorphic to homeomorphic conversion method is determined to be valid due to its post-mesh morphing maximum deviations being on the same order as the post-mesh morphing maximum deviations of the ideal homeomorphic case. The usefulness of the automated heteromorphic to homeomorphic conversion method is demonstrated by simulating manufacturing defects on the pressure surface of a compressor blade model, morphing a structural finite element analysis mesh to match the geometry of compressor blades with simulated manufacturing defects, performing a modal analysis, and making observations on the effect of the simulated manufacturing defects on the modal characteristics of the compressor blade.

This research developed comprehensive model updating systems for real structures including a hybrid approach which enhanced existing deterministic model updating techniques by providing measures to incorporate uncertainties in a computationally efficient way compared to probabilistic model updating approaches. Further, utilizing the developed hybrid approach a methodology was developed to assess the deterioration of reinforced concrete buildings under serviceability loading conditions. The developed methodologies in the research were successfully validated utilizing two real benchmark structures at Queensland University of Technology equipped with continuous monitoring systems.

In Model-Driven Engineering, model transformation is a key model management operation, used to translate models between notations. Model transformation can be used for many engineering activities, for instance as a preliminary to merging models from different meta- models, or to generate codes from diagrammatic models. A mapping model needs to be developed (the transformation specification) to represent relations between concepts from the metamodels. The evaluation of the mapping model creates new challenges, for both conventional verification and validation, and also in guaranteeing that models generated by applying the transformation specification to source models still retain the intention of the initial transformation requirements. Most model transformation creates and evaluates a transformation specification in an ad-hoc manner. The specifications are usu- ally unstructured, and the quality of the transformations can only be assessed when the transformations are used. Analysis is not systematically applied even when the transformations are in use, so there is no way to determine whether the transformations are correct and consistent. This thesis addresses the problem of systematic creation and analysis of model transformation, via a facility for planning and designing model transformations which have conceptual-level properties that are tractable to formal analysis. We proposed a framework that provides steps to systematically build a model transformation specification, a visual notation for specifying model transformation and a template-based approach for producing a formal specification that is not just structure-equivalent but also amenable to formal analysis. The framework allows evaluation of syntactic and semantic correctness of generated models, metamodel coverage, and semantic correctness of the transformations themselves, with the help of snapshot analysis using patterns.

This work was undertaken as a final year project in Computer Engineering, within the Department of Computer and Information Science at Linköping University. At the Department of Computer and Information Science, work oriented at testing and analyzing applications is developed to provide solution approaches to problems that arise in system product development. One of the current applications being developed is the ‘Systemics Analyst’. The purpose of the application is to facilitate for system developers with an analysis tool permitting insights on system reliability, system critical components, how to improve the system and the consequences as well as risks of a system failure. The purpose of the present thesis was to enhance the ‘Systemics Analyst application’ by incorporating an ‘automated model-based reliability prediction’ and ‘fault tree analysis’ modules. This enables reliability prediction and fault tree analysis diagrams to be generated automatically from the data files and relieves the system developer from manual creation of the diagrams. The enhanced Systemics Analyst application managed to present the results in respective models using the new incorporated functionality. To accomplish the above tasks, ‘Systemics Analyst application’ was integrated with a library that handles automated model-based reliability prediction and fault tree analysis, which is described in this thesis. The reader will be guided through the steps that are performed to accomplish the tasks with illustrating figures, methods and code examples in order to provide a closer vision of the work performed.

This thesis is concerned with developing a probabilistic formulation of model-based vision using generalised flexible template models. It includes the design and implementation of a system which extends flexible template models to include grey level information in the object representation for image interpretation. This system was designed to deal with microscope images where the different stain and illumination conditions during the image acquisition process produce a strong correlation between density profile and geometric shape. This approach is based on statistical knowledge from a training set of examples. The variability of the shape-grey level relationships is characterised by applying principal component analysis to the shape-grey level vector extracted from the training set. The main modes of variation of each object class are encoded with a generic object formulation constrained by the training set limits. This formulation adapts to the diversity and irregularities of shape and view during the object recognition process. The modes of variation are used to generate new object instances for the matching process of new image data. A genetic algorithm method is used to find the best possible explanation for a candidate of a given model, based on the probability distribution of all possible matches. This approach is demonstrated by its application to microscope images of brain cells. It provides the means to obtain information such as brain cells density and distribution. This information could be useful in the understanding of the development and properties of some Central Nervous System (<I>CNS</I>) related diseases, such as in studies on the effects of <I>HIV</I> in<I> CNS</I> where neuronal loss is expected. The performance of the <I>SGmodel </I>system was compared with manual neuron counts from domain experts. The results show no significant difference between <I>SGmodel</I> and manual neuron estimates. The observation of bigger differences between the counts of the domain experts underlines the automated approach importance to perform an objective analysis.

The Unified Modeling Language (UML) is a standard language adopted by the Object Management Group (OMG) for writing object-oriented (OO) descriptions of software systems. UML allows the analyst to add class-level and system-level constraints. However, UML does not describe how to check the correctness of these constraints. Recent studies have shown that Symbolic Model Checking can effectively verify large software specifications. In this thesis, we investigate how to use model checking to verify constraints of UML specifications. We describe the process of specifying, translating and verifying UML specifications for an elevator example. We use the Cadence Symbolic Model Verifier (SMV) to verify the system properties. We demonstrate how to write a UML specification that can be easily translated to SMV. We propose a set of rules and guidelines to translate UML specifications to SMV, and then use these to translate a non-trivial UML elevator specification to SMV. We look at errors detected throughout the specification, translation and verification process, to see how well they reveal errors, ambiguities and omissions in the user requirements.

Abstract Testing is an important part of quality assurance, and the use of agile processes, continuous integration and DevOps is increasing the pressure for automating all aspects of testing. Testing through graphical user interfaces (GUIs) is commonly automated by scripts that are captured or manually created with a script editor, automating the execution of test cases. A major challenge with script-based GUI test automation is the manual effort required for maintaining the scripts when the GUI changes. Model-based testing (MBT) is an approach for automating also the design of test cases. Traditionally, models for MBT are designed manually with a modelling tool, and an MBT tool is used for generating abstract test cases from the model. Then, an adapter is implemented to translate the abstract test cases into concrete test cases that can be executed on system under test (SUT). When the GUI changes, the model has to be updated and the test cases can be generated from the updated model, reducing the maintenance effort. However, designing models and implementing adapters requires effort and specialized expertise. The main research questions of this thesis are 1) how to automatically extract state-based models of software systems with GUI, and 2) how to use the extracted models to automate testing. Our focus is on using dynamic analysis through the GUI during automated exploration of the system, and we concentrate on desktop applications. Our results show that extracting state models through GUI is possible and the models can be used to generate regression test cases, but a more promising approach is to use model comparison on extracted models of consequent system versions to automatically detect changes between the versions<br>Tiivistelmä Testaaminen on tärkeä osa laadun varmistusta. Ketterät kehitysprosessit ja jatkuva integrointi lisäävät tarvetta automatisoida kaikki testauksen osa-alueet. Testaus graafisten käyttöliittymien kautta automatisoidaan yleensä skripteinä, jotka luodaan joko tallentamalla manuaalista testausta tai kirjoittamalla käyttäen skriptieditoria. Tällöin scriptit automatisoivat testitapausten suorittamista. Muutokset graafisessa käyttöliittymässä vaativat scriptien päivittämistä ja scriptien ylläpitoon kuluva työmäärä on iso ongelma. Mallipohjaisessa testauksessa automatisoidaan testien suorittamisen lisäksi myös testitapausten suunnittelu. Perinteisesti mallipohjaisessa testauksessa mallit suunnitellaan manuaalisesti käyttämällä mallinnustyökalua, ja mallista luodaan abstrakteja testitapauksia automaattisesti mallipohjaisen testauksen työkalun avulla. Sen jälkeen implementoidaan adapteri, joka muuttaa abstraktit testitapaukset konkreettisiksi, jotta ne voidaan suorittaa testattavassa järjestelmässä. Kun testattava graafinen käyttöliittymä muuttuu, vain mallia täytyy päivittää ja testitapaukset voidaan luoda automaattisesti uudelleen, vähentäen ylläpitoon käytettävää työmäärää. Mallien suunnittelu ja adapterien implementointi vaatii kuitenkin huomattavan työmäärän ja erikoisosaamista. Tämä väitöskirja tutkii 1) voidaanko tilamalleja luoda automaattisesti järjestelmistä, joissa on graafinen käyttöliittymä, ja 2) voidaanko automaattisesti luotuja tilamalleja käyttää testauksen automatisointiin. Tutkimus keskittyy työpöytäsovelluksiin ja dynaamisen analyysin käyttämiseen graafisen käyttöliittymän kautta järjestelmän automatisoidun läpikäynnin aikana. Tutkimustulokset osoittavat, että tilamallien automaattinen luominen graafisen käyttöliittymän kautta on mahdollista, ja malleja voidaan käyttää testitapausten generointiin regressiotestauksessa. Lupaavampi lähestymistapa on kuitenkin vertailla malleja, jotka on luotu järjestelmän peräkkäisistä versioista, ja havaita versioiden väliset muutokset automaattisesti

European Union has set a target to install nearly 200 million smart metersspread over Europe before 2020, this leads into a vast increase of sensitiveinformation flow for Distribution System Operators (DSO’s), simultaneously thisleads to raised cyber security threats. The in and outgoing information of the DSOneeds to be processed and stored by different Information technology (IT)- andOperational Technology (OT)-systems depending on the information. High demandsare therefore required of the enterprise cyber security to be able to protect theenterprise IT- and OT-systems. Sensitive customer information and a variety ofservices and functionality is examples that could be fatal to a DSO if compromised.For instance, if someone with bad intentions has the possibility to tinker with yourelectricity, while you’re away on holiday. If they succeed with the attack and shuttingdown the house electricity, your food stored in your fridge and freezer would mostlikely to be rotted, additionally damage from defrost water leaking could cause severedamaging on walls and floors. In this thesis, a detailed reference model of theadvanced metering architecture (AMI) has been produced to support enterprisesinvolved in the process of implementing smart meter architecture and to adapt to newrequirements regarding cyber security. This has been conduct using foreseeti's toolsecuriCAD, foreseeti is a proactive cyber security company using architecturemanagement. SecuriCAD is a modeling tool that can conduct cyber security analysis,where the user can see how long time it would take for a professional penetrationtester to penetrate the systems in the model depending of the set up and defenseattributes of the architecture. By varying defense mechanisms of the systems, fourscenarios have been defined and used to formulate recommendations based oncalculations of the advanced meter architecture. Recommendation in brief: Use smalland distinct network zones with strict communication rules between them. Do diligentsecurity arrangements for the system administrator PC. The usage of IntrusionProtection System (IPS) in the right fashion can delay the attacker with a percentageof 46% or greater.<br>Europeiska Unionen har satt upp ett mål att installera nära 200miljoner smarta elmätare innan år 2020, spritt utöver Europa, implementeringen ledertill en rejäl ökning av känsliga dataflöden för El-distributörer och intresset av cyberattacker ökar. Både ingående och utgående information behöver processas och lagraspå olika IT- och OT-system beroende på informationen. Höga krav gällande ITsäkerhet ställs för att skydda till exempel känslig kundinformation samt en mängdvarierande tjänster och funktioner som är implementerade i systemen. Typer avattacker är till exempel om någon lyckats få kontroll over eltillgängligheten och skullestänga av elektriciteten till hushåll vilket skulle till exempel leda till allvarligafuktskador till följd av läckage från frysen. I den här uppsatsen så har en tillräckligtdetaljerad referens modell för smart elmätar arkitektur tagits fram för att möjliggörasäkerhetsanalyser och för att underlätta för företag i en potentiell implementation avsmart elmätare arkitektur. Ett verktyg som heter securiCAD som är utvecklat avforeseeti har använts för att modellera arkitekturen. securiCAD är ett modelleringsverktyg som använder sig av avancerade beräknings algoritmer för beräkna hur långtid det skulle ta för en professionell penetrationstestare att lyckats penetrera de olikasystem med olika sorters attacker beroende på försvarsmekanismer och hurarkitekturen är uppbyggd. Genom att variera systemens försvar och processer så harfyra scenarion definierats. Med hjälp av resultaten av de fyra scenarierna så harrekommendationer tagits fram. Rekommendationer i korthet: Använd små ochdistinkta nätverkszoner med tydliga regler som till exempel vilka system som fårkommunicera med varandra och vilket håll som kommunikationen är tillåten.Noggranna säkerhetsåtgärder hos systemadministratörens dator. Användningen avIPS: er, genom att placera och använda IPS: er på rätt sätt så kan man fördröjaattacker med mer än 46% enligt jämförelser mellan de olika scenarier.