| 1. |
- Drego, Adelia Darlene, 1987-
(författare)
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On Early Product Development in the Context of Aircraft Thermal Management Design
- 2024
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Military aircraft face several contemporary challenges. From a thermal management perspective, they include the more extensive use of electrically driven technologies and more power-hungry tactical systems. These systems demand more cooling power from the aircraft thermal management system. Thermal management systems of modern aircraft face another challenge with shrinking heat sink capability. This is because of platform design aspects. Increasing use of composite materials for airframe skin over traditional metals impedes the dissipation of waste heat through skin. Infrared and radar cross-section signatures are minimised to improve aircraft stealth by minimising the cross-sectional areas of ram air intakes. This reduces the amount of waste heat that can be dumped over-board through ram air. And there are only two options for heat sinks, air (ram or engine fan) and fuel. All these contemporary challenges create a strong need to carry out thermal management design effectively at the aircraft concept stage.A framework is presented in this thesis that demonstrates how effective thermal management design at the concept stage can be conducted at an aircraft developer like Saab. The framework was created with data collection through workshops, document studies, interviews, and group discussions conducted at Saab. Therefore, the framework is based on industrial reality. It can be tested for application at the aircraft concept stage of Saab projects. Further, the methods created in this thesis can be used in a broader context that transcend their primary application in thermal management design. They can also complement other methods presented in literature on aircraft thermal management. Thus, this thesis makes industrial and scientific contributions to aircraft thermal management design.
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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 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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Environmental Agent-Based Modelling For A Firefighting System Of Systems
- 2022
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Ingår i: 33rd Congress of the International Council of the Aeronautical Sciences.
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Konferensbidrag (refereegranskat)abstract
- In the field of System-of-Systems (SoS) engineering, the study of interactions between complex systems froma holistic point of view is important for finding emerging behaviours. To observe as many behaviours aspossible, especially when field testing is not a viable option, simulations play an important role in design spaceexploration and formulation for the Firefighting SoS framework. The presented work describes an AgentBased Model (ABM) approach for simulation of wildfire spread and its detection using collaborating vehicles:Unmanned Aerial Vehicles (UAVs), or partly autonomous air- and land-based vehicles. Implemented in theopen-source software NetLogo, the usage of its Geographic Information System (GIS) extension allows tosimulate scenarios at specific locations. This ABM will be used in the future for Agent-Based Simulations(ABS) for the study of an SoS framework oriented to firefighting, including design and optimization of the SoS,constituent systems and their subsystems.
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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. |
- Scholz, Dieter, et al.
(författare)
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Fuel Consumption Due to Shaft Power Off-takes from The Engine
- 2013
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Ingår i: Proceedings of the 4th International Workshop on Aircraft System Technologies. - Aachen : Shaker Verlag. - 9783844018509 ; , s. 169-179
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper looks at fuel consumption due to shaft power off-takes from the engine and the related increase in the aircraft’s fuel consumption. It presents a review and comparison of published and unpublished data on this kind of consumption. The paper presents results from the TURBOMATCH engine simulation model, calibrated to real world engine data. A generic equation is derived for the calculation of fuel consumption due to shaft power extraction. Main result is the shaft power factor kP found to be in the order of 0.002 N/W for a typical cruise flight. This yields an amazingly high efficiency for power generation by shaft power extraction from a turbo fan engine of more than 70 %.
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