| 1. |
- Knöös Franzén, Ludvig, 1990-, et al.
(författare)
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A Breakdown of System of Systems Needs Using Architecture Frameworks, Ontologies and Description Logic Reasoning
- 2021
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Ingår i: Aerospace. - : MDPI. - 2226-4310. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- Aerospace systems are connected with the operational environment and other systems in general. The focus in aerospace product development is consequently shifting from a singular system perspective to a System-of-Systems (SoS) perspective. This increasing complexity gives rise to new levels of uncertainty that must be understood and managed to produce aerospace solutions for an ever-changing future. This paper presents an approach to using architecture frameworks, and ontologies with description logic reasoning capabilities, to break down SoS needs into required capabilities and functions. The intention of this approach is to provide a consistent way of obtaining the functions to be realized in order to meet the overarching capabilities and needs of an SoS. The breakdown with an architecture framework results in an initial design space representation of functions to be performed. The captured knowledge is then represented in an ontology with description logic reasoning capabilities, which provides a more flexible way to expand and process the initial design space representation obtained from the architecture framework. The proposed approach is ultimately tested in a search and rescue case study, partly based on the operations of the Swedish Maritime Administration. The results show that it is possible to break down SoS needs in a consistent way and that ontology with description logic reasoning can be used to process the captured knowledge to both expand and reduce an available design space representation.
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| 2. |
- Knöös Franzén, Ludvig, 1990-, et al.
(författare)
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A System of Systems Approach for Search and Rescue Missions
- 2020
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Konferensbidrag (refereegranskat)abstract
- System-of-Systems Engineering (SoSE) has become a constantly growing field within product development for complex systems. Systems are becoming more and more connected with other systems and the operational environment in general. This takes the development process to new levels of complexity where high degrees of uncertainties are expected due to ever occurring changes in the operational environment, and other external factors such as politics, economy, and technology. This creates a need of being able to understand the influence of changes early in the development process and to facilitate the systems? perseverance. The focus of the development shifts from fulfilling specific requirements, to being able to meet needs and deliver capabilities over time. Additionally, modeling and simulation for complex systems and System-of-Systems (SoS) becomes a valued alternative to the economically prohibited and almost impossible prototype testing. In consideration of this problem, the presented work introduces a method for both modeling and simulation of a SoS. The method uses ontology with description logic reasoning to derive and narrow down a SoS design space which is further analyzed using Agent Based Simulation (ABS). A Search and Rescue (SAR) scenario is used as a case study to test the method. Measures of Effectiveness (MoE), based on the time it takes to find a rescue subject and the cost of doing so, are used to evaluate the SoS performances. The presented method is envisioned to be used early in the development of complex systems and SoS to increase the overall understanding of them.
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| 3. |
- Knöös Franzén, Ludvig, 1990-
(författare)
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A System of Systems View in Early Product Development : An Ontology-Based Approach
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The concept of system-of-systems is becoming increasingly common and relevant in many engineering applications. Today’s highly interconnected world entails that more and more systems have dependencies on other systems. This increasing number of interdependencies results in new levels of complexity that must be managed in the early development of new products. Different viewpoints must also be handled to understand the many layers of a system-of-systems and its surrounding context. An ever-changing future results in uncertainty about the operational environment but also other aspects, such as available technologies, which complicates the matter even further. Traditional approaches for early product development can be used to some extent, but the complexity, scale and sheer number of interconnections in system-of-systems require a holistic perspective to obtain an early understanding of the problem, design spaces, and multiple aspects involved. This dissertation aims to present a method that has been developed to address the demand for a more holistic system-of-systems view in early product development. Overall, the method consists of four parts that together show how design spaces for system-of-systems can be generated and later processed to find suitable solutions. Search and rescue operations have been used as examples of system-of-systems throughout this work and in the development of the presented method. The first two parts of the method are based on architecture frameworks and ontologies with description logic reasoning capabilities. An architecture framework is here used to break down system-of-system needs into functions to be fulfilled by constituent systems. Ontologies are thereafter used to represent the outcome and the resulting system-of-system design spaces with involved entities and their relationships. Description logic reasoning can subsequently be used to process the available design spaces and suggest suitable system-of-system solutions. The last two parts of the method build upon a concept exploration and estimation approach, together with visual analytics. The approach illustrates how individual system concepts can be estimated from an ontology-represented design space, and how visual analytics can be used to explore different system-of-system viewpoints at an early stage. Based on the outcomes of the presented method, this dissertation contributes a holistic take on early product development from a system-of-systems perspective.
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| 4. |
- Knöös Franzén, Ludvig, 1990-
(författare)
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An Ontological and Reasoning Approach to System of Systems
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- System-of-Systems (SoS) are all around us and are becoming more common in today’s highly interconnected world. Systems are connected with other systems and have strong dependencies with their operational environments. This leads to an increased level of complexity and risk during product development. A holistic view, and an SoS perspective, is consequently needed in order to develop an early understanding of the available design spaces for new system solutions. This thesis suggests a method that has been developed for this purpose, and to meet the demand for a more holistic product development. Overall, the method consists of two correlated approaches that show how a design space for SoSs can be generated and later processed with, for example, design space reductions. Search and Rescue (SAR) operations have been used as examples of typical SoSs throughout this work and in the development of the presented method. An architecture framework has been used to introduce a standardized and consistent way of understanding the relationships that exist between needs, capabilities and functions. This approach can consequently be used to generate a design space of functions to be performed to meet the overarching needs of an SoS. The second approach has been based on ontology and description logic reasoning. Ontology has here been used to represent an SoS design space with, for example, available SAR assets and their relationships with the operational environment. An SoS representation in an ontology model introduces additional expressiveness and the design space processing capabilities needed for a holistic design process and product development. Based on these results, this thesis and its suggested method and approaches contribute to holistic product development from an SoS perspective.
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| 5. |
- Knöös Franzén, Ludvig, 1990-, et al.
(författare)
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An Ontological Approach to System of Systems Engineering in Product Development
- 2019
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Ingår i: Linköping Electronic Conference Proceedings 162 (2019). - Linköping : Linköping University Electronic Press. - 9789175190068 ; , s. 35-44
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Konferensbidrag (refereegranskat)abstract
- This paper presents an approach to system-of-systems engineering for product development with the use of ontology. A proposed method for building as well as using ontology to generate and explore system-of-systems design spaces based on identified system-of-system needs is presented. The method is largely built to cover the first levels of related work, where a process for system of systems in the context of product development is introduced. Within this work, it is shown that scenarios for a system-of-systems can be used to identify needs and subsequently the system-of-systems capabilities that fulfils them. The allocation of capabilities to possible constituent systems is used to show the available design space. The proposed method of this paper therefore addresses these initial challenges and provides a framework for approaching the system-of-systems design space creation using ontology. A case study is used to test the method on a fictitious search and rescue scenario based on available resources and information from the Swedish Maritime Administration. The case study shows that a representation of a system-of-systems scenario can be created in an ontology using the method. The ontology provides a representation of the involved entities from the fictitious scenario and their existing relationships. Defined ontology classes containing conditions are used to represent the identified needs for the system-of-systems. The invocation of a description logic reasoner is subsequently used to classify and create an inferred ontology where the available system-of-systems solutions are represented as sub-classes and individuals of the defined classes representing the needs. Finally, several classes representing different possible system-of-systems needs are used to explore the available design space and to identify the most persistent solutions of the case study.
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| 6. |
- Knöös Franzén, Ludvig, 1990-, et al.
(författare)
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Ontology-Assisted Aircraft Concept Generation
- 2022
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Ingår i: 33rd Congress of the International Council of the Aeronautical Sciences. - Stockholm, Sweden.
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Konferensbidrag (refereegranskat)abstract
- This paper presents a method for generating a geometrical representation of a concept aircraft from an ontology description. An ontology is used as an overarching knowledge base where entities, such as required functions, their design alternatives, and requirements can be represented. Description logic reasoning is then used to process the available design space and generate suitable concepts to fulfil desired functions, as well as indicate suitable approaches for a subsequent sizing procedure. As ontology representations are limited in terms of numerical calculation capabilities, the obtained concept information must be extracted for additional processing. Further investigations, such as statistical analyses, are consequently performed in order to expand the available information of the concept generated from the ontology. This expansion is performed to obtain estimates of required inputs for a continued geometrical sizing procedure. The outcome of the method is an estimation of the concept’s geometry and its characteristics. This information can from here be reintroduced into the ontology representation for further processing and to expand the original knowledge base. A case study is introduced to test the proposed method and to show how it can be used to estimate the characteristics of an already existing aircraft from basic requirements and configuration details. The results from the method and sizing are also compared with publicly available data for the reference aircraft to see how accurate the estimates were.
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| 7. |
- Knöös Franzén, Ludvig, 1990-, et al.
(författare)
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Ontology-Represented Design Space Processing
- 2021
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Ingår i: AIAA AVIATION 2021 Forum, August 2-6, 2021, VIRTUAL EVENT. - USA : American Institute of Aeronautics and Astronautics.
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Konferensbidrag (refereegranskat)abstract
- This paper presents a method for generating a design space intended for aircraft design with the use of ontologies. Aircraft design, seen from a System-of-Systems (SoS) perspective, gives an idea of the complicated relationships and complexities that need to be managed and understood to develop suitable systems for an ever-changing future. Holistic SoS analyzes are used to investigate customer and stakeholder needs that then can be broken down into capabilities and subsequently functions to be performed by involved Constituent Systems (CS), sub-systems and system elements. Ontologies with description logic reasoning capabilities are then used to represent the outcome of the breakdown. An ontology development and integration process can afterwards be used to merge different ontologies together and by that map the derived functions to means that can implement them. This results in an available SoS design space that can be further processed using a description logic reasoner. The outcome of the proposed method is a reduced available design space of functions to be performed and their respective design alternatives. Search and Rescue (SAR) operations based on the Swedish Maritime Administration (SMA) are used as a case study to test the proposed method and to illustrate how it can be utilized. At the end, a design space of alternatives for a new type of search aircraft is generated with ontology and description logic reasoning.
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| 8. |
- Lovaco, Jorge, et al.
(författare)
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Agent-Based Simulation and Ontology Integration for System-of-System Exploration
- 2022
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Ingår i: IDEAS 2022 conference.
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Konferensbidrag (refereegranskat)abstract
- The increasing interest in System-of-Systems (SoS) for engineering applications are introducing new challenges that must be overcome at an early design stage. One of these is the integration of different tools that can be used to make predictions about a system under development and how these together can be used to predict SoS performances by comparison of parameter spaces.The purpose of this paper is therefore to illustrate how different SoS architectures can be modeled, simulated, and evaluated throughout different scenarios by different teams of researchers following a common workflow.An ontology is used as an overarching knowledge base where information about entities, such as scenario details, can be extracted and used for the setup of Agentbased Simulations(ABS) through a tool integration software acting as master that controls the correct execution of the defined workflow.The tool integration software also enables additional modelling capabilities, such as a Design of Experiments (DOE) definition for design space explorations, an Optimizer with different algorithms, user-defined Python scripts, etc.
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| 9. |
- Oprea, Alexandra, 1987-, et al.
(författare)
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Connecting system simulation to aircraft concept development
- 2021
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Ingår i: Proceedings of the 32nd Congress of the International Council of the Aeronautical Sciences. - 9783932182914 - 9781713841012 ; , s. 1088-1104
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study presents a solution for connecting system simulation and aircraft concept development using solely open standards. An easy-to-use optimisation framework for aircraft concept development is created with the help of the Modelica, Functional Mock-up Interface (FMI), and System Structure and Parameterization (SSP) standards, and the open source tools OpenModelica and OMSimulator. The framework allows for conceptual aircraft design accounting for transient phenomena by means of standardised integration of dynamic simulation models of aircraft subsystems. The framework is applied to an industry-relevant use case concerning the concept development of a generic fighter aircraft. The generality and modularity of the framework and its straightforward implementation enables tailoring of the optimisation goals to the user needs and requirements. The adoption of industry-wide standards allows for the inclusion of system simulation models developed in the modelling tool best suited for each discipline, thus integrating dynamic system simulation already at the aircraft conceptual design stage.
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| 10. |
- Schön, Sofia, et al.
(författare)
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Exploring the Impact of Model Fidelity Through Interactive Visualizations for System of Systems
- 2022
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Ingår i: AIAA SciTech 2022 Forum, January 3-7, 2022, San Diego, CA & Virtual. - USA : American Institute of Aeronautics and Astronautics.
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Konferensbidrag (refereegranskat)abstract
- Studying Systems of Systems (SoS) in relation to Measures of Effectiveness (MoE) is a difficult task. This is due to that SoSs include several system levels and operate in changing environments. There are also computational challenges related to modeling and simulation of SoSs and it is difficult to predict behaviors. Therefore, choosing model fidelity for system models and assessing their impact on MoE is of high relevance to the field. This paper illustrates an approach to modeling and simulation for SoSs that can be used to assess the impact of scenario parameters and to explore when level of fidelity on system level affects the MoE. This is made through a case study based on Search and Rescue (SAR) operations where a Design Of Experiments (DOE) of scenario parameters is performed and simulations of each scenario experiment is performed. The case study shows how Agent Based Simulations (ABS) can be used to obtain the MoE for different SAR missions and how the choice of model fidelity for one of the aircraft’s sensors has different effects for various scenarios. Additionally, a Visual Analytics (VA) approach is introduced and used to create a dashboard for visualizing the obtained simulation results in an interactive way. This allows users to make explorations on the resulting data and see how different scenarios influence the performance of each SoS. Furthermore, the results show that changes in scenario parameters impacts the MoE and that this is difficult to predict, at least using a quantitative method. The results point to the importance of exploration for both the scenario, using an interactive dashboard, but also to the importance of exploring the simulation model to study emerging phenomenon. The results of this approach have raised questions regarding if a more qualitative approach of studying SoSs could be beneficial to study MoE for SoSs and if inspiration could be transferred from a more scientific point of view of systems.
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