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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.
21

Towards a Model-Based Systems Engineering Approach for Robotic Manufacturing Process Modelling with Automatic FMEA Generation

Korsunovs, Aleksandrs, Doikin, Aleksandr, Campean, Felician, Kabir, Sohag, Hernandez, E.M., Taggart, D., Parker, S., Mills, G. 29 May 2022 (has links)
Yes / The process of generating FMEA following document-centric approach is tedious and susceptible to human error. This paper presents preliminary methodology for robotic manufacturing process modelling in MBSE environment with a scope of automating multiple steps of the modelling process using ontology. This is followed by the reasoning towards automatic generation of process FMEA from the MBSE model. The proposed methodology allows to establish robust and self-synchronising links between process-relevant information, reduce the likelihood of human error, and scale down time expenses.
22

Co-spécification système exécutable basée sur des modèles : application à la conduite interactive d’un procédé industriel critique / Executable system co-specification based on models : Application to interactive conduct of critical industrial process

Bouffaron, Fabien 08 January 2016 (has links)
Dans la mesure où un système est un ensemble d'éléments en interaction, la difficulté pour un ingénieur système est de guider l’architecture d'un modèle « total » du système en tant qu'ensemble de modèles « locaux » d’ingénieries interdisciplinaires en interaction. Les travaux présentés dans ce mémoire s’intéressent plus précisément à la nature heuristique, spécifiante et exécutable de cette relation « totale » de couplage afin de construire un modèle virtuel du système à faire. La perspective holonique retenue permet de considérer cette relation de couplage de façon descriptive du TOUT et prescriptive de chacune des PARTIES aussi bien en regard de la situation-système à percevoir que des constitutifs-système à architecturer. Ainsi, nous avons revisité cette relation en tant que processus itératif, récursif et collaboratif de co-spécification-système visant à supporter la requête de connaissances auprès de chacune des ingénieries spécialistes délivrant en retour les modèles constitutifs satisfaisant des exigences systèmes. Notre environnement de co-modélisation-système se compose alors d’un ensemble d’environnements élémentaires de modélisation de constituants-système, avec pour objectif de préserver les outils, méthodes et processus de travail de chacune des parties prenantes. La modélisation au niveau système s’appuie sur le langage de modélisation « SysML » pour architecturer l’ensemble des connaissances. La vérification et la validation système s’effectue par co-exécution de modèles autour d’un bus de co-simulation, y compris in-situ avec la plate-forme d’expérimentation CISPI du projet SAFETECH du CRAN constituant notre cas d’application / Insofar as a system is a set of interacting elements, the difficulty for a system engineer is to guide the whole model architecture of a system as a set of interdisciplinary engineering part models interacting. The works presented in this thesis are specifically interested in the heuristic, specifying and executable nature of this whole relationship coupling to design a virtual model of the system-of-interest. The holonic perspectives allows us to consider this coupling relationship as descriptive of a WHOLE (H) and prescriptive of each parts as well in regards to system situation to perceive, as system-elements to architect. In this sense, we revisit this relation as an iterative, recursive and collaborative process of system co-specification to the quest of knowledge with each specialist engineering delivering constitutive models satisfying basic requirements. Our system co-modelling environment is itself composed of a set of system-components modelling environment, with the stated objective to preserve tools, methods and works of each stakeholders in order to facilitate the expression of their skills. The modelling at a system level is based on the system modelling language (SysML) to architecture the set of knowledge. Verification and validation are performed by co-execution of models around a co-simulation bus, including CISPI platform of SAFETECH project of CRAN constituting our case study
23

Multi-layer syntactical model transformation for model based systems engineering

Kwon, Ky-Sang 03 November 2011 (has links)
This dissertation develops a new model transformation approach that supports engineering model integration, which is essential to support contemporary interdisciplinary system design processes. We extend traditional model transformation, which has been primarily used for software engineering, to enable model-based systems engineering (MBSE) so that the model transformation can handle more general engineering models. We identify two issues that arise when applying the traditional model transformation to general engineering modeling domains. The first is instance data integration: the traditional model transformation theory does not deal with instance data, which is essential for executing engineering models in engineering tools. The second is syntactical inconsistency: various engineering tools represent engineering models in a proprietary syntax. However, the traditional model transformation cannot handle this syntactic diversity. In order to address these two issues, we propose a new multi-layer syntactical model transformation approach. For the instance integration issue, this approach generates model transformation rules for instance data from the result of a model transformation that is developed for user model integration, which is the normal purpose of traditional model transformation. For the syntactical inconsistency issue, we introduce the concept of the complete meta-model for defining how to represent a model syntactically as well as semantically. Our approach addresses the syntactical inconsistency issue by generating necessary complete meta-models using a special type of model transformation.
24

A model-based systems engineering methodology to make engineering analysis of discrete-event logistics systems more cost-accessible

Thiers, George 27 August 2014 (has links)
This dissertation supports human decision-making with a Model-Based Systems Engineering methodology enabling engineering analysis, and in particular Operations Research analysis of discrete-event logistics systems, to be more widely used in a cost-effective and correct manner. A methodology is a collection of related processes, methods, and tools, and the process of interest is posing a question about a system model and then identifying and building answering analysis models. Methods and tools are the novelty of this dissertation, which when applied to the process will enable the dissertation's goal. One method which directly enables the goal is adding automation to analysis model-building. Another method is abstraction, to make explicit a frequently-used bridge to analysis and also expose analysis model-building repetition to justify automation. A third method is formalization, to capture knowledge for reuse and also enable automation without human interpreters. The methodology, which is itself a contribution, also includes two supporting tool contributions. A tool to support the abstraction method is a definition of a token-flow network, an abstract concept which generalizes many aspects of discrete-event logistics systems and underlies many analyses of them. Another tool to support the formalization method is a definition of a well-formed question, the result of an initial study of semantics, categories, and patterns in questions about models which induce engineering analysis. This is more general than queries about models in any specific modeling language, and also more general than queries answerable by navigating through a model and retrieving recorded information. A final contribution follows from investigating tools for the automation method. Analysis model-building is a model-to-model transformation, and languages and tools for model-to-model transformation already exist in Model-Driven Architecture of software. The contribution considers if and how these tools can be re-purposed by contrasting software object-oriented code generation and engineering analysis model-building. It is argued that both use cases share a common transformation paradigm but executed at different relative levels of abstraction, and the argument is supported by showing how several Operations Research analyses can be defined in an object-oriented way across multiple layered instance-of abstraction levels. Enabling Operations Research analysis of discrete-event logistics systems to be more widely used in a cost-effective and correct manner requires considering fundamental questions about what knowledge is required to answer a question about a system, how to formally capture that knowledge, and what that capture enables. Developments here are promising, but provide only limited answers and leave much room for future work.
25

Integrating models and simulations of continuous dynamic system behavior into SysML

Johnson, Thomas Alex 05 May 2008 (has links)
Contemporary systems engineering problems are becoming increasingly complex as they are handled by geographically distributed design teams, constrained by the objectives of multiple stakeholders, and inundated by large quantities of design information. According to the principles of model-based systems engineering (MBSE), engineers can effectively manage increasing complexity by replacing document-centric design methods with computerized, model-based approaches. In this thesis, modeling constructs from SysML and Modelica are integrated to improve support for MBSE. The Object Management Group has recently developed the Systems Modeling Language (OMG SysML ) to provide a comprehensive set constructs for modeling many common aspects of systems engineering problems (e.g. system requirements, structures, functions). Complementing these SysML constructs, the Modelica language has emerged as a standard for modeling the continuous dynamics (CD) of systems in terms of hybrid discrete- event and differential algebraic equation systems. The integration of SysML and Modelica is explored from three different perspectives: the definition of CD models in SysML; the use of graph transformations to automate the transformation of SysML CD models into Modelica models; and the integration of CD models and other SysML models (e.g. structural, requirements) through the depiction of simulation experiments and engineering analyses. Throughout the thesis, example models of a car suspension and a hydraulically-powered excavator are used for demonstration. The core result of this work is the provision of modeling abilities that do not exist independently in SysML or Modelica. These abilities allow systems engineers to prescribe necessary system analyses and relate them to stakeholder concerns and other system aspects. Moreover, this work provides a basis for model integration which can be generalized and re-specialized for integrating other modeling formalisms into SysML.
26

Using domain specific languages to capture design knowledge for model-based systems engineering

Kerzhner, Aleksandr A. 08 April 2009 (has links)
Design synthesis is a fundamental engineering task that involves the creation of structure from a desired functional specification; it involves both creating a system topology as well as sizing the system's components. Although the use of computer tools is common throughout the design process, design synthesis is often a task left to the designer. At the synthesis stage of the design process, designers have an extensive choice of design alternatives that need to be considered and evaluated. Designers can benefit from computational synthesis methods in the creative phase of the design process. Recent increases in computational power allow automated synthesis methods for rapidly generating a large number of design solutions. Combining an automated synthesis method with an evaluation framework allows for a more thorough exploration of the design space as well as for a reduction of the time and cost needed to design a system. To facilitate computational synthesis, knowledge about feasible system configurations must be captured. Since it is difficult to capture such synthesis knowledge about any possible system, a design domain must be chosen. In this thesis, the design domain is hydraulic systems. In this thesis, Model-Driven Software Development concepts are leveraged to create a framework to automate the synthesis of hydraulic systems will be presented and demonstrated. This includes the presentation of a domain specific language to describe the function and structure of hydraulic systems as well as a framework for synthesizing hydraulic systems using graph grammars to generate system topologies. Also, a method using graph grammars for generating analysis models from the described structural system representations is presented. This approach fits in the context of Model-Based Systems Engineering where a variety of formal models are used to represent knowledge about a system. It uses the Systems Modeling Language developed by The Object Management Group (OMG SysML™) as a unifying language for model definition.
27

INTEGRATED SYSTEM ARCHITECTURE DEVELOPMENT AND ANALYSIS FRAMEWORK APPLIED TO A DISTRICT COOLING SYSTEM

Akshay Satish Dalvi (9741170) 07 January 2021 (has links)
<div>The internal and external interactions between the complex structural and behavioral characteristics of the system of interest and the surrounding environment result in unpredictable emergent behaviors. These emergent behaviors are not well understood, especially when modeled using the traditional top-down systems engineering approach. The intrinsic nature of current complex systems has called for an elegant solution that provides an integrated framework in Model-Based Systems Engineering. A considerable gap exists to integrate system engineering activities and engineering analysis, which results in high risk and cost. This thesis presents a framework that incorporates indefinite and definite modeling aspects that are developed to determine the complexity that arises during the development phases of the system. This framework provides a workflow for modeling complex systems using Systems Modeling Language (SysML) that captures the system’s requirements, behavior, structure, and analytical aspects at both problem definition and solution levels. This research introduces a new level/dimension to the framework to support engineering analysis integrated with the system architecture model using FMI standards. A workflow is provided that provides the enabling methodological capabilities. It starts with a statement of need and ends with system requirement verification. Detailed traceability is established that glues system engineering and engineering analysis together. Besides, a method is proposed for predicting the system’s complexity by calculating the complexity index that can be used to assess the complexity of the existing system and guide the design and development of a new system. To test and demonstrate this framework, a case study consisting of a complex district cooling system is implemented. The case study shows the framework’s capabilities in enabling the successful modeling of a complex district cooling system. The system architecture model was developed using SysML and the engineering analysis model using Modelica. The proposed framework supports system requirements verification activity. The analysis results show that the district chiller model developed using Modelica produces chilled water below 6.6 degrees Celsius, which satisfies the system requirement for the district chiller system captured in the SysML tool. Similarly, many such requirement verification capabilities using dynamic simulation integration with the high-level model provides the ability to perform continuous analysis and simulation during the system development process. The systems architecture complexity index is measured for the district cooling case study from the black-box and white box-perspective. The measured complexity index showed that the system architecture’s behavioral aspect increases exponentially compared to the structural aspect. The systems architecture’s complexity index at black-box and white-box was 4.998 and 67.3927, respectively.</div>
28

Simulation modularer Produktarchitekturen durch modellbasierte Konfiguration

Dambietz, Florian M., Krause, Dieter 07 September 2021 (has links)
Im Zuge der Globalisierung sehen sich produzierende Unternehmen mit einem kontinuierlich anwachsenden Wettbewerbsdruck konfrontiert. Aufgrund dessen sehen sich viele Marktakteure zu einer intensivierten Spezialisierung gezwungen, um auf kunden-individuelle Anforderungen eingehen zu können. Einen möglichen Lösungsansatz zur Bewältigung dieser Herausforderung bietet der Ansatz der Modularisierung. Hier wird allerdings nicht konkret ein Baukasten definiert, vielmehr werden verschiedene Alternativen generiert. Die Entscheidung, welcher Baukasten schlussendlich implementiert wird, fällt meist aufgrund einiger weniger Einflussfaktoren sowie maßgeblich durch Expertenentscheidungen. An dieser Stelle setzt der vorliegende Beitrag an. Um ein quantifizierbares und ganzheitliches Kriterium zur Unter-stützung der Auswahl modularer Baukastensysteme zu bieten, wird eine multifaktorielle Simulation eingesetzt. Einer der maßgeblichen Aspekte derer ist die beidseitige Inbezugnahme von sowohl Kunden- als auch Unternehmensperspektive. Dies wird v.a. durch die Verwendung eines dynamischen Produktkonfigurationssystems ermöglicht. Um die zugrundeliegenden, teils komplexen Produktarchitekturen datentechnisch konsistent und pflegbar zu halten, wird zusätzlich der Einsatz einer modellbasierten Datenstruktur aufgezeigt. Die Verwendung des Model-Based Systems-Engineering (MBSE) Ansatzes hilf dabei, die vielschichtigen Zusammenhänge des Modulbaukastens in einer konsistenten und maschinenlesbaren Form auszudrücken. Somit kann das Konfigurationssystem produktunabhängig auf die Ontologie der zugrundeliegenden Datenstruktur zugreifen. Für die Baukastensimulation wird dieses Konfigurationssystem rekursiv für mehrere Kundenanfragen und alternative Baukästen eingesetzt, um anschließend mittels eines geometrisch-mathematischen Algorithmus ein multi-dimensionales Entscheidungskriterium hinsichtlich der Baukasten-performance zu generieren.
29

MBSE-basierte Produktkonfiguratoren zur Analyse der Modularisierung bei der Entwicklung modularer Baukastensysteme

Seiler, Florian, Schwede, Lea-Nadine, Krause, Dieter 03 January 2020 (has links)
Der im Zuge der Globalisierung immer stärker anwachsende Wettbewerb im Bereich produzierender Unternehmen führt zu einem kontinuierlichen Wettlauf um stetig kürzer werdende Produktionslaufzeiten. Aufgrund dessen ist eine kontinuierliche Spezialisierung mit produktspezifischen Fertigungssystemen der Akteure am Markt zu verzeichnen, die direkt zu einer erhöhten Nachfrage von Sondermaschinen führt (Krause 2018). Diese geforderte Spezialisierung lässt eine interne Standardisierung für die Hersteller kaum zu und führt zu einer extrem hohen Variantenvielfalt, deren Beherrschung eine der Kernaufgaben bei der Sicherstellung der Wettbewerbsfähigkeit darstellt. Insbesondere große Produktstrukturen sind aufgrund der anfallenden Datenmenge und dem resultierenden, hohen Grad an Verknüpfungen schwierig zu verwalten (Blees 2011). Eine Möglichkeit, die interne Vielfalt bei einer gleichbleibenden externen Vielfalt zu reduzieren und somit den enormen Umfang der Produktarchitektur und deren Folgekosten einzuschränken, bietet die Modularisierung (Krause 2018). Die Entwicklung von modularen Produktstrukturen eröffnet mittels entsprechender Standardisierung die Möglichkeit, durch Modul-, Plattform-, und Baukastenentwicklung den Zielkonflikt zwischen Produktkosten und -vielfalt zu lösen (Ehrlenspiel 2009). Ein solcher Baukasten wird als notwendiges Mittel zur Beherrschung der Vielfalt betrachtet [...] Ein Ansatz zur Lösung dieser Problemstellung ist in der Literatur durch die Verwendung von PLM(Product-Lifecycle-Management)-Systemen beschrieben. Ein entsprechendes PLM-System soll die im Unternehmen existierende Daten- und Softwarestruktur verbinden und als Single-Source of Truth (Riesener 2017) fungieren, um die Konsistenz der Modelle zu gewährleisten. Allerdings wird gerade bei der Verwendung von Modellen bei der Schaffung und Verwaltung der Produktarchitektur deutlich, dass ein PLM-System hierzu nicht vollumfänglich dazu in der Lage ist, als einheitlicher Datenstamm zu fungieren. Hierbei ist die Ontologie, die Verwendung „einheitlicher Vokabeln“ (Kaufmann et al. 2014) zwischen den Systemen, um z. B. eine Konsistenzprüfung bei der Konfiguration zu implementieren, eine nicht zu unterschätzende Herausforderung bei der Umsetzung auf Basis eines reinen PLM-Systems. Wie in diesem Beitrag beschrieben wird, lässt sich diese Lücke mithilfe des MBSE (Model-Based Systems Engineering) schließen. [... aus der Einleitung]
30

Dimensioning of Charging Infrastructure Using Model-Based Systems Engineering / Dimensionering av laddinfrastruktur genom modellbaserad systemteknik

Jansson, Daniel, Niklasson, Nils January 2022 (has links)
This thesis work is performed in collaboration with Syntell AB and a client company interested in assistance with charging infrastructure dimensioning. The aim of this thesis is to develop an executable, generalizable model that can aid decision making regarding charging infrastructure. Furthermore, this is done within a Model-Based Systems Engineering (MBSE) context, which enables representation of the system as a model.  As the data and model concerning the client company is classified, it is not presented in this report. Instead, to further enhance the aim of developing a generalizable model, a test case is produced for this project work. This case consists of passenger electric vehicles and chargers in a metropolitan setting, where data is gathered from public sources.  The results show that the model is executable and flexible to fit any type of electric vehicle and different specifications of chargers. Using an MBSE approach enables the project owner to customize the model development for the specific use case. Additionally, defining a system in focus establishes what the system uptime is, enabling calculations of availability. The results for this specific use case are interpreted to show how the model can be used to aid the dimensioning of charging infrastructure using the model output. To further verify the model representation of the system, the model can be run in live-mode, where vehicles and chargers can be added while the model is running to instantly examine the system dynamics.  Concluding, the method for utilizing the model to evaluate systems availability is described. The model output, as well as the thorough description of the model, can be used to increase the knowledge within MBSE for executable modeling. / Detta projekt utförs i samarbete med Syntell AB och en tredje part som är intresserad av att förbättra sitt beslutsunderlag gällande dimensionering av laddinfrastruktur. Målet med arbetet är att utveckla en exekverbar och generaliserbar modell som kan användas för att underlätta dimensionering av laddinfrastruktur. Vidare så genomförs arbetet inom ramen för MBSE, vilket möjliggör en representation av systemet med hjälp av en modell. Eftersom kunddatan är konfidentiell appliceras modellen på ett fabricerat användningsfall som underlag för denna rapport. Detta baserar sig på elektriska personbilar i stadsmiljö, där data hämtas från publika källor. Att modellen används på två olika användningsfall stärker argumenten kring generaliserbarhet. Resultatet som presenteras är främst i syfte att demonstrera tolkning av resultat samt att grundligt förklara modellen. Resultaten visar att modellen är exekverbar och flexibel för att kunna anpassas utifrån godtyckligt elektriskt fordon och olika specifikationer för laddstationer. Genom att definiera ett system i fokus kan systemets drifttid utgöra grund för att kunna beräkna tillgänglighet. Resultaten tolkas i det specifika användningsfallet för att illustrera hur modellen kan användas för att underlätta en beslutsprocess gällande dimensionering av laddinfrastruktur. För att ytterligare verifiera modellens representation av verkligheten används ett interaktivt live-mode, där fordon och laddare kan läggas till under körning för att direkt undersöka systemdynamiken. Detta är ett viktigt verktyg vid kommunikation med intressenter för att stärka förtroendet för simuleringsresultat.  Sammanfattningsvis beskrivs metoden för att använda modellen till att undersöka systemtillgänglighet. Modellens utdata, tillsammans med beskrivningen av modellen, kan användas för att utöka kunskapen inom MBSE för exekverbar modellering.

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