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- Sundin, Maria, 1965, et al.
(författare)
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Space Sports - Sailing in Space
- 2016
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Ingår i: Proceedings from icSports 2016, 4th International Conference on Sport Sciences Research and Technology Support, Porto, Portugal, 7-9 november 2016. - : SCITEPRESS - Science and Technology Publications. - 9789897582059 ; , s. 141-146
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Konferensbidrag (refereegranskat)abstract
- Titan is the largest moon of Saturn, and apart from the Earth it is the only body in our solar system where a liquid exists on the surface. Within the last ten years a system of lakes and rivers have been discovered. The climate and seasonal cycles of Titan are still not very well known, but the composition and pressure are fairly well established. Perhaps in the future boats will sail the lakes of Titan for research purposes or even sport. The purpose of this paper is to give an overview of the concept of space sports, the conditions of Titan and to calculate important parameters of sailing such as floatability, stability, hull resistance and sail forces. This paper shows that if a sailing yacht on Titan will have twice as large displacement as on Earth, it will be 2.6 times less stable for the same beam. Since friction will be smaller, it will be faster than on Earth at low speed, but significantly slower at high speeds due to the wave generation. The same sail area is required to get the same sail forces if the average wind is 3 m/s, while a 9 times larger sail area is required for if the wind speed is only 1 m/s.
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| 4. |
- Petersson, Jesper, 1974
(författare)
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Technospatialities and telehealthcare: Unfolding new spaces of visibility
- 2016
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Ingår i: Information, Communication & Society. - 1369-118X .- 1468-4462. ; 19:6, s. 824-842
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Tidskriftsartikel (refereegranskat)abstract
- The umbrella term ‘telehealthcare’ denotes an array of information and communication technology-based solutions for digitally connecting citizens with healthcare services. Guided by the conviction that bodies can be translated into digital data which may serve as the basis for clinical decisions made elsewhere, these designs are widely assumed to enable a mode of healthcare delivery which is independent of space and time. Addressing the increasing use of telehealthcare for personalized health monitoring targeting the growing populations of elderly and chronic-care patients, this paper suggests that such designs invariably unfold new spaces of visibility. Based on an analysis of articles published in a leading telehealthcare journal, I argue that these new visibilities do not provide a window onto something that is already there. Instead, such visibilities are shaped by the way techno-medical practices and knowledge production processes are intertwined with a specific politico-economic agenda. The paper explores differences with respect to the positioning of older people and chronic-care patients in relation to two versions of health monitoring. While each version represents an attempt to promote individual freedom, improve health outcomes and ensure a functioning healthcare system, contrasting rationales are involved and different types of spaces are being unfolded.
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| 5. |
- Wiedner, M.C., et al.
(författare)
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The origins space telescope and the heterodyne receiver for origins (HERO)
- 2019
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Ingår i: ISSTT 2019 - 30th International Symposium on Space Terahertz Technology, Proceedings Book. ; , s. 204-207
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Konferensbidrag (refereegranskat)abstract
- The Origins Space Telescope is one of four large mission concept studies carried out by NASA for the 2020 Decadal survey. Origins is a far-infrared telescope designed to understand the evolution of galaxies and black holes, to follow the trail of water from protostars to habitable planets and to search for biosignatures in the atmospheres of exoplanets. The Heterodyne Receiver for Origins (HERO) is the high spectral resolution receiver. It is the first heterodyne array receiver designed to fly on a satellite and an example for possible future focal plane arrays for space. HERO has focal plane arrays with nine pixels in two polarization. HERO covers a large frequency range between 486 and 2700 GHz in only 4 frequency bands, requiring local oscillators with fractional bandwidth of 45%. HERO uses the best superconducting mixers with noise temperatures between 1 and 3 hf/k and an intermediate bandwidth of 6 to 8 GHz. HERO can carry out dual polarization and dual-frequency observations. The major challenges for the HERO design are the low cooling power and the low electrical power available on a spacecraft, which impact the choice of the cryogenic amplifiers and backends. SiGe cryogenic amplifiers with a consumption of less than 0.5 mW, as well as CMOS spectrometers with a power consumption below 2W are the baseline for HERO. The development plan includes broadband (45%) multiplier-amplifier chains, low noise mixers (1-3 hf/k), low-power consuming (< 05.mW) cryogenic amplifiers and low-power consuming spectrometer backends (< 2W).
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| 6. |
- Sundin, Maria, 1965, et al.
(författare)
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Space sports – Sailing and equestrian sports in space
- 2019
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Ingår i: Communications in Computer and Information Science. - Cham : Springer International Publishing. - 1865-0937 .- 1865-0929. ; 975, s. 75-85
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Konferensbidrag (refereegranskat)abstract
- Sports in space? Is it at all possible to practice sports in our solar system but not on Planet Earth? Mars is our closest neighboring planet, and Titan is the largest moon of Saturn, and apart from the Earth it is the only body in our solar system where a liquid exists on the surface. Within the last ten years a system of lakes and rivers has been discovered. The climate and seasonal cycles of Titan are still not very well known, but the composition and pressure are fairly well established. Perhaps in the future boats will sail the lakes of Titan for research purposes or even sport. The purpose of this paper is to give an overview of the concept of space sports, looking at sailing on Titan and equestrian sports on Mars. For sailing, the conditions of Titan necessitate calculations of important parameters of sailing such as floatability, stability, hull resistance and sail forces. This paper shows that a sailing yacht on Titan will have twice as large displacement as on Earth and it will be 2.6 times less stable for the same beam. Since friction will be smaller, it will be faster than on Earth at low speed, but significantly slower at high speeds due to the wave generation. The same sail area is required to get the same sail forces if the average wind is 3 m/s, while a 9 times larger sail area is required if the wind speed is only 1 m/s. Equestrian sports on Mars could be a possibility, even if challenges exist in form of a cold climate and thin atmosphere with noxious gases. Due to the lower gravity sports such as show jumping, dressage and races would yield new records and new patterns of locomotion.
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| 7. |
- Xin, Zhao, et al.
(författare)
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A framework for optimization of hybrid aircraft
- 2019
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Ingår i: Proceedings of the ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME). - 9780791858608 ; 3
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Konferensbidrag (refereegranskat)abstract
- To achieve the goals of substantial improvements in efficiency and emissions set by Flightpath 2050, fundamentally different concepts are required. As one of the most promising solutions, electrification of the aircraft primary propulsion is currently a prime focus of research and development. Unconventional propulsion sub-systems, mainly the electrical power system, associated thermal management system and transmission system, provide a variety of options for integration in the existing propulsion systems. Different combinations of the gas turbine and the unconventional propulsion sub-systems introduce different configurations and operation control strategies. The trade-off between the use of the two energy sources, jet fuel and electrical energy, is primarily a result of the trade-offs between efficiencies and sizing characteristics of these sub-systems. The aircraft structure and performance are the final carrier of these trade-offs. Hence, full design space exploration of various hybrid derivatives requires global investigation of the entire aircraft considering these key propulsion sub-systems and the aircraft structure and performance, as well as their interactions. This paper presents a recent contribution of the development for a physics-based simulation and optimization platform for hybrid electric aircraft conceptual design. Modeling of each subsystem and the aircraft structure are described as well as the aircraft performance modeling and integration technique. With a focus on the key propulsion sub-systems, aircraft structure and performance that interfaces with existing conceptual design frameworks, this platform aims at full design space exploration of various hybrid concepts at a low TRL level.
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| 8. |
- Yu, Yushu, 1985, et al.
(författare)
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6D Pose Task Trajectory Tracking for a Class of 3D Aerial Manipulator From Differential Flatness
- 2019
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Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 7, s. 52257-52265
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the dynamics and control of a novel class of aerial manipulator for the purpose of end effector full pose trajectory tracking are investigated. The 6D pose of the end effector is set as a part of the flat output, from which the conditions that the system has the proposed flat output is obtained. The control law for the end effector tracking purpose is designed. The core part of the controller is an almost global controller in the configuration space of the system. From the transformation between the state space and the output space, the tracking control of the end effector in SE (3) is also achieved. The stability of the controlled system is analyzed. A numerical example is presented to demonstrate the theoretical analysis.
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| 9. |
- Müller, Jakob, 1987
(författare)
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Towards automated conceptual design space exploration
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In mature and safety-concerned industries, such as the aerospace industry, product development is often incremental and design solutions are limited to improvements of an existing design. Radical changes to the known product architecture are avoided, for reasons of reliability, lack of technology or lack of design space exploration (DSE) methods. This thesis aims to investigate into the challenges for DSE, and how it can be improved to be faster, wider and more systematic. This research has been undertaken in four different research projects, addressing the challenges of the aerospace industry. The process of exploring the design space, the set of all possible designs, can be divided into three phases: to define the design space boundaries, to populate this design space with concepts, and lastly, to analyse the different concepts to find the one which provides the highest value. A deficiency in the description of functions and constraints which constitute the design space dimensions and boundaries, rooted in the lack of methods, has been identified to reduce the available search space already in the beginning. To populate this search space, developers need to generate representations of their new designs. These representations, commonly 3D geometries in the form of CAD models, are too rigid in the form they are used today. Therefore, it is expensive to create many variants, which differ in solutions and shape. This reduces the design space population to only a few concepts, derived from the legacy design. The analysis of alternative concepts is challenged through different maturities and variety of concepts. The coverage of multiple hierarchical search spaces, from geometry over solutions to value, has been identified as a driver for wider DSE. Furthermore, the need for a product development approach that is capable to bridge the levels of modelling abstraction. Enhanced Function-Means (EF-M) modelling, a function model applied in all studies referenced in this thesis, bridges the abstraction from a verbal description to a teleological graph, while enabling a more systematic capture of the design space boundaries. However, a subsequent gap towards geometry models could be observed in all studies. This hindered a faster design space exploration, since extensive manual labour is required to bridge these abstraction levels. For further work, the closing of the abstraction gap in the product modelling methods is seen as the primary goal for further work, either by extending the already applied function- and geometry modelling methods, or by including other frameworks.
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| 10. |
- Ott, T., et al.
(författare)
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AOCS design for the ATHENA X-ray telescope : challenges and solutions
- 2018
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Ingår i: CEAS Space Journal. - : Springer-Verlag Wien. - 1868-2502 .- 1868-2510. ; 10:4, s. 519-534
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Tidskriftsartikel (refereegranskat)abstract
- The ATHENA—Advanced Telescope for High-ENergy Astrophysics—mission is currently assessed in a phase A feasibility study as L-class mission in ESA’s Cosmic Vision 2015–2025 plan, with launch foreseen in 2028. Primary mission goal is the mapping of hot gas structures and the determination of their physical properties to search for supermassive black holes. ATHENA is an X-ray telescope with a focal length of 12 m. It has a mass of ~ 7000 kg and it is ~ 15 m high with a diameter of ~ 3 m. The main mass is distributed to the mirror on the one side of the spacecraft and to the science instrument module on the other side of the spacecraft. To achieve its science goals, ATHENA performs a sky survey with precision line-of-sight pointing requirements in the order of arc seconds for absolute pointing and sub-arc seconds for relative pointing in time windows > 1 ks, all at 95% confidence level. That is very demanding for large X-ray telescopes. In addition to the precision pointing requirements, ATHENA cannot violate a certain sun exclusion zone. This is a hard constraint to prevent any stray-light falling onto the instruments, as it would immediately destroy them. The sky survey is defined by an observation plan that is demanding in terms of availability and thus spacecraft agility. The pointing and agility requirements and the fact that ATHENA is a spacecraft with high mass and volume introduce several design challenges for the attitude and orbit control system. This paper presents those challenges, corresponding solutions, and preliminary results, which have been achieved during the phase A study led by Airbus in Friedrichshafen, Germany. The main focus and contribution of this paper are the identification of research and development needs for attitude and orbit control systems to enable the ATHENA mission. In this respect, the ATHENA design challenges are discussed and addressed with the state-of-the-art design methods. This paper concludes with the main identified technology development needs and formulates specific research questions related to practical design problems. In particular, the following attitude and orbit control system design challenges are addressed: autonomous and agile large angle slew manoeuvres with exclusion zones, availability for science observations, precision line-of-sight determination as well as analysis during the design process using the ESA Pointing Error Engineering Tool and pointing control with a hexapod as line-of-sight actuator in the control loop. The last challenge, namely, the hexapod in the control loop, is without precedence in Europe and to the best knowledge of the authors in the world.
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