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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.
1

The application of multi-attribute optimisation as a systems engineering tool in an automotive CAE environment

Sutton, Paul January 2012 (has links)
Multi-Attribute Optimisation (MAO) is proposed as a tool for delivering high value products within the systems engineering approach taken in the automotive industry. This work focuses on MAO methods that use Computer Aided Engineering (CAE) analyses to build a metamodel of system behaviour. A review of the literature and current Jaguar Land Rover optimisation methods showed that the number of samples required to build a metamodel could be estimated using the number of input variables. The application of these estimation methods to a concept airbox design showed that this guidance may not be sufficient to fully capture the complexity of system behaviour in the metamodelling method. The use of the number of input variables and their ranges are proposed as a new approach to the scaling of sample sizes. As a corollary to the issue of the sample size required for accurate metamodelling, the sample required to estimate the error was also examined. This found that the estimation of the global error by additional samples may be impractical in the industrial context. CAE is an important input to the MAO process and must balance the efficiency and accuracy of the model to be suitable for application in the optimisation process. Accurate prediction of automotive attributes may require the use of new CAE techniques such as multi-physics methods. For this, the fluid structure interaction assessment of the durability of internal components in the fuel tank due to slosh was examined. However, application of the StarCD-Abaqus Direct couple and Abaqus Combined Eularian Lagrangian was unsuitable for this fuel slosh application. Further work would be required to assess the suitability of other multi-physics methods in an MAO architecture. Application of the MAO method to an automotive airbox shows the potential for improving both product design and lead time.
2

Use of domain-specific language in test automation

Hussain, Ambreen 04 1900 (has links)
The primary aim of this research project was to investigate techniques to replace the complicated process of testing embedded systems in automotive domain. The multi-component domain was composed of different hardware to be used in testing procedure which increased the level of difficulty in testing for an operator. As a result, an existing semi-automated testing procedure was replaced by more simpler and efficient framework (ViBATA). A key step taken in this scenario was the replacement of manual GUI interface with the scriptable one to enhance the automation. This was achieved by building a Domain-specific language which allowed test definition in the form of human readable scripts which could be stored for later use. A DSL is a scripting language defined for a particular domain with compact expressiveness. In this case the domain is testing embedded systems in general and automotive systems in particular. The final product was a test case specification document in the form of XML as an output of generated code from this DSL which will be input to ViBATA to make test specification component automated. In this research a comparative analysis of existing DSLs for alternative domains and investigation of their applicability to the presented domain was also performed. The technologies used in this project are Xtext to define the DSL grammar, Xtend to generate code in Java and Simple framework to generate output in XML. The stages involved in DSL development and how these stages were implemented is covered in this thesis. The developed DSL for this domain is tested for automotive and calculator systems in this thesis which proved that this is more general and flexible. The DSL is consistent, efficient and automated test specification component of testing framework in embedded systems.
3

Towards a framework for engineering big data: An automotive systems perspective

Byrne, Thomas J., Campean, Felician, Neagu, Daniel 05 1900 (has links)
no / Demand for more sophisticated models to meet big data expectations require significant data repository obligations, operating concurrently in higher-level applications. Current models provide only disjointed modelling paradigms. The proposed framework addresses the need for higher-level abstraction, using low-level logic in the form of axioms, from which higher-level functionality is logically derived. The framework facilitates definition and usage of subjective structures across the cyber-physical system domain, and is intended to converge the range of heterogeneous data-driven objects.
4

Troubleshooting Trucks : Automated Planning and Diagnosis / Felsökning av lastbilar : automatiserad planering och diagnos

Warnquist, Håkan January 2015 (has links)
This thesis considers computer-assisted troubleshooting of heavy vehicles such as trucks and buses. In this setting, the person that is troubleshooting a vehicle problem is assisted by a computer that is capable of listing possible faults that can explain the problem and gives recommendations of which actions to take in order to solve the problem such that the expected cost of restoring the vehicle is low. To achieve this, such a system must be capable of solving two problems: the diagnosis problem of finding which the possible faults are and the decision problem of deciding which action should be taken. The diagnosis problem has been approached using Bayesian network models. Frameworks have been developed for the case when the vehicle is in the workshop only and for remote diagnosis when the vehicle is monitored during longer periods of time. The decision problem has been solved by creating planners that select actions such that the expected cost of repairing the vehicle is minimized. New methods, algorithms, and models have been developed for improving the performance of the planner. The theory developed has been evaluated on models of an auxiliary braking system, a fuel injection system, and an engine temperature control and monitoring system.
5

Optimizing the Automotive Security Development Process in Early Process Design Phases

Jakobs, Christine 02 August 2023 (has links)
Security is a relatively new topic in the automotive industry. In the former days, the only security defense methods were the engine immobilizer and the anti-theft alarm system. The rising connection of vehicles to external networks made it necessary to extend the security effort by introducing security development processes. These processes include, amongothers, risk analysis and treatment steps. In parallel, the development of ISO/SAE 21434 and UN-ECE No. R155 started. The long development cycles in the automotive industry made it necessary to align the development processes' early designs with the standards' draft releases. This work aims to design a new consistent, complete and efficient security development process, aligned with the normative references. The resulting development process design aligns with the overall development methodology of the underlying, evaluated development process. Use cases serve as a basis for evaluating improvements and the method designs. This work concentrates on the left leg of the V-Model. Nevertheless, future work targets extensions for a holistic development approach for safety and security.:I. Foundation 1. Introduction 2. Automotive Development 3. Methodology II. Meta-Functional Aspects 4. Dependability as an Umbrella-Term 5. Security Taxonomy 6. Terms and Definitions III. Security Development Process Design 7. Security Relevance Evaluation 8. Function-oriented Security Risk Analysis 9. Security Risk Analysis on System Level 10. Risk Treatment IV. Use Cases and Evaluation 11. Evaluation Criteria 12. Use Case: Security Relevance Evaluation 13. Use Case: Function-oriented Security Risk Analysis 14. Use Case: System Security Risk Analysis 15. Use Case: Risk Treatment V. Closing 16. Discussion 17. Conclusion 18. Future Work Appendix A. Attacker Model Categories and Rating Appendix B. Basic Threat Classes for System SRA Appendix C. Categories of Defense Method Properties
6

END-TO-END TIMING ANALYSIS OF TASK-CHAINS

Jin, Zhiqun, Zhu, Shijie January 2017 (has links)
Many automotive systems are real-time systems, which means that not only correct operationsbut also appropriate timings are their main requirements. Considering the in uence that end-to-end delay might have on the performance of the systems, the calculation of it is of necessity.Abundant techniques have actually been proposed, and some of them have already been applied intopractical systems. In spite of this, some further work still needs to be done. The target of thisthesis is to evaluate and compare two end-to-end timing analysis methods from dierent aspectssuch as data age, consumption time, and then decide which method is a prior choice for end-to-end timing analysis. The experiments can be divided into three blocks, system generation andend-to-end delay calculation by two methods respectively. The experiments focus on two kinds ofperformance parameters, data age and the consumption time that these two methods cost duringtheir execution. By changing the system generating parameters like task number and periods, thechanges of performances of the two methods are analyzed. The performances of the two dierentmethods are also compared when they are applied into the same automotive systems. According tothe results of the experiments, the second method can calculate more accurate data age and consumeless time than the rst method does.
7

End-to-end Timing Analysis of Task-Chains

Zhiqun, Jin, Shijie, Zhu January 2017 (has links)
Many automotive systems are real-time systems, which means that not only correct operationsbut also appropriate timings are their main requirements. Considering the in uence that end-to-end delay might have on the performance of the systems, the calculation of it is of necessity.Abundant techniques have actually been proposed, and some of them have already been applied intopractical systems. In spite of this, some further work still needs to be done. The target of thisthesis is to evaluate and compare two end-to-end timing analysis methods from dierent aspectssuch as data age, consumption time, and then decide which method is a prior choice for end-to-end timing analysis. The experiments can be divided into three blocks, system generation andend-to-end delay calculation by two methods respectively. The experiments focus on two kinds ofperformance parameters, data age and the consumption time that these two methods cost duringtheir execution. By changing the system generating parameters like task number and periods, thechanges of performances of the two methods are analyzed. The performances of the two dierentmethods are also compared when they are applied into the same automotive systems. According tothe results of the experiments, the second method can calculate more accurate data age and consumeless time than the rst method does.
8

[en] CONTROL STRATEGIES APPLIED TO GROUND VEHICLES HANDLING PROBLEM IN PRE-DEFINED CLOSED TRAJECTORIES / [pt] ESTRATÉGIAS DE CONTROLE APLICADAS AO PROBLEMA DE DIRIGIBILIDADE DE VEÍCULOS TERRESTRES EM TRAJETÓRIAS FECHADAS PRÉ-DEFINIDAS

FERNANDO HEY 09 October 2008 (has links)
[pt] Apresenta-se o uso das ferramentas lineares de Controle Clássico (Lugar Geométrico das Raízes) e Moderno (Realimentação de Estado e de Saída e Alocação de Pólos) para estabelecer os ajustes dos controladores adotados no problema de acompanhamento de trajetórias em traçados fechados por veículos terrestres, procurando reproduzir o comportamento do ser humano no comando deste tipo de sistema. Os modelos adotados para o veículo são lineares (funções de transferência e matrizes de estado e de entrada), porém a caracterização da trajetória fechada é geometricamente não-linear. Verifica-se deste modo como o projeto de um controle linear satisfaz as condições não lineares associadas. Os conceitos e ferramentas conhecidos são aplicados em diversos tipo de traçados, para diferentes condições do veículo - velocidade, limites de esterçamento, etc - e, a partir das simulações realizadas, são analisadas as características de comportamento do veículo - acelerações, estabilidade, etc - e comparadas as previsões dos projetos lineares com os resultados encontrados. É feita ainda uma breve introdução ao emprego do Controle Ótimo no problema de acompanhamento de traçados, utilizando um modelo bastante simplificado do veículo, e verificando as condições necessárias para se estabelecer a trajetória ótima em um traçado aberto, dado como critério o tempo mínimo para percorrê-lo. / [en] The use of classic and modern linear control tools (root locus and output regulation) is presented to determine the parameters of controllers used to follow a pre-defined closed path, in a way to approach the vehicle behavior and human actions when driving a car. The car is represented by linear models (transfer functions, state-space matrix), but the relation between the car and the closed path is non linear. It is verified how the project of a linear controller deals with the non linear characteristics of the closed loop. The concepts and tools of linear control are applied to some kinds of paths in different vehicle conditions (speed, steering angle limits, etc), and the results of simulations show the characteristics of the car, like accelerations, stability and position on the track. It`s also presented a little introduction to the problem of determine an optimal trajectory to run a corner, given the initial and final velocities and initial and final positions. In this case a very simple model is considered and the solution is based on open paths analysis.
9

A Method for Optimised Allocation of System Architectures with Real-time Constraints

Marcus, Ventovaara, Arman, Hasanbegović January 2018 (has links)
Optimised allocation of system architectures is a well researched area as it can greatly reduce the developmental cost of systems and increase performance and reliability in their respective applications.In conjunction with the recent shift from federated to integrated architectures in automotive, and the increasing complexity of computer systems, both in terms of software and hardware, the applications of design space exploration and optimised allocation of system architectures are of great interest.This thesis proposes a method to derive architectures and their allocations for systems with real-time constraints.The method implements integer linear programming to solve for an optimised allocation of system architectures according to a set of linear constraints while taking resource requirements, communication dependencies, and manual design choices into account.Additionally, this thesis describes and evaluates an industrial use case using the method wherein the timing characteristics of a system were evaluated, and, the method applied to simultaneously derive a system architecture, and, an optimised allocation of the system architecture.This thesis presents evidence and validations that suggest the viability of the method and its use case in an industrial setting.The work in this thesis sets precedence for future research and development, as well as future applications of the method in both industry and academia.
10

Requirements Engineering Process according to Automotive Standards in a Model-driven Framework / Processus d’ingénierie des exigences dans un environnment à base de modèles selon les normes automobiles

Adedjouma, Morayo 12 July 2012 (has links)
L'industrie automobile des systèmes embarqués critiques est confrontée de nos jours à une complexité croissante, tandis que les coûts, les performances en termes d'intelligence, les caractéristiques, les capacités et les délais de commercialisation de leurs produits sont constamment remises en question. Face à cela, l'objectif principal pour les constructeurs et fournisseurs automobiles devient désormais de contrôler la qualité et la fiabilité des systèmes mécatroniques et embarqués. L'existence de normes internationales comme le HIS Automotive SPICE et l’ISO26262 est une contrainte supplémentaire qu'ils doivent prendre en compte s’ils veulent atteindre cet objectif. De plus, assurer la bonne gestion de la sécurité et la qualité du produit ne suffit pas: il est essentiel de veiller à ce que nous produisons un système qui n'est pas seulement sécuritaire et bien, mais aussi que nous produisons le bon système. Cela induit donc une plus grande prise en compte des exigences.Dans cette thèse, nous traitons le challenge du développement des systèmes embarqués automobiles suivant l’Ingénierie Dirigée par les Modèles (IDM) qui répondent aux exigences des utilisateurs et des standards du domaine et qui permettent de maîtriser davantage la qualité des produits développés. Le problème à résoudre a été abordé sur plusieurs phases qui sont ensuite utilisés conjointement. En premier, nous définissons un métamodèle fusionnant les approches orienté qualité produit et qualité processus selon respectivement les normes ISO26262 et SPICE. Puis, dans un but de certification, nous proposons une méthodologie générique basée sur ce métamodèle commun où une évaluation du processus de développement induite par l’HIS standard ainsi qu’une évaluation de la sécurité fonctionnelle induite par l’ISO2626 sont simultanément effectuées. Ce résultat est traduit au travers de la définition d'un framework outillé où nous appliquons la méthode d'évaluation propre au standard SPICE. En deuxième phase, nous définissons un métamodèle pour gérer les actifs de sécurité concernant ces normes automobiles au niveau produit. Ce métamodèle définit comment capturer les exigences et l’architecture d’un système de telle manière qu'ils puissent être traçables entre eux et également traçables depuis des documents de spécifications d’origine. Enfin, une approche à base de modèle où l'interaction des modèles de processus et le produit est géré afin de répondre aux besoins identifiés dans la première phase est développé pour soutenir la gestion de projet. L'approche utilise la modélisation des processus et leur mesure pour améliorer le contrôle et le suivi de projet et de réduire par la même les coûts et les fréquences de replanification.Les avantages de la contribution sont démontrés sur une application pilote automobile, validant ainsi le travail de recherche au vue des faiblesses identifiées préalablement dans le contexte. / The embedded safety-critical systems industry is facing an exponential increase in the complexity and variety of systems and devices while costs, performance in terms of intelligence, features, capacities and time to market are constantly challenged. The main objective for automotive manufacturers and suppliers is now becoming the control of quality and the dependability of embedded and mechatronic systems. The existence of internationally recognized standards such as the Automotive SPICE and ISO26262 is a further constraint that must be managed to meet this objective. Nevertheless, ensuring sound management of safety and viewpoints is insufficient. It is also essential to ensure that we produce a system that is not only compliant and well-defined, but also that we produce the “right” system. Therefore, this leads to greater consideration of the requirements.In this thesis, we address the challenge of development of automotive embedded systems following the model-driven engineering paradigm that meet the user needs and the regulatory constraints of the domain and that further mastered the quality of developed product. We resolve the problem in many steps which are subsequently used jointly. In the first phase, we define a merging approach which embodies a product quality and process quality approaches regarding the ISO26262 and SPICE standards following the model-driven engineering paradigm. Then, in a certification assessment purpose, we propose a generic methodology where an HIS assessment and a functional safety audit is simultaneously performed without altering their original meanings. This commitment results into the definition of a tooled framework where we apply the SPICE assessment method to the common metamodel defined from the merging work. In a second phase, we define a metamodel for manage safety assets regarding these automotive standards at product level. This metamodel defines how the requirements and architecture of a system can be captured in such a way that they can be traceable from each other and from origin specifications documents. Finally, a model-based approach where the interaction of process and product models is managed to address requirements identified in the precedent phases is developed to support project management. The approach uses process modeling and measurement to improve the control and the monitoring of project and to reduce the cost and frequency of re-planning.The benefits of the contribution are demonstrated on an ongoing automotive pilot application, thereby validating the research work against the weaknesses identified prealably in the context.

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