| 1. |
- Jones, Geraint H., et al.
(författare)
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The Comet Interceptor Mission
- 2024
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Ingår i: Space Science Reviews. - : Springer Nature. - 0038-6308 .- 1572-9672. ; 220:1
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Tidskriftsartikel (refereegranskat)abstract
- Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum Δ V capability of 600 ms − 1 . Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule.
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| 2. |
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| 3. |
- Lindgren, Per, et al.
(författare)
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Robust real-time applications in Timber
- 2006
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Ingår i: 2006 IEEE International Conference on Electro/information Technology. - Piscataway, NJ : IEEE Communications Society. - 0780395921 ; , s. 191-196
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Konferensbidrag (refereegranskat)abstract
- Embedded systems are often operating under hard real-time constraints, for example in automotive applications. For such systems, robustness and reliability are crucial, which calls for rigorous system design and methodologies for validation. In this paper we advocate a design methodology for robust, realtime systems, based on Timber; a pure reactive system model that allows for formal reasoning about various system properties. We outline how system specifications in Timber can be "compiled" into efficient standalone executables for general light-weight microcontroller platforms. Methods for resource analysis and implications to system dimensioning and validation are further discussed.
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| 4. |
- Lindgren, Per, et al.
(författare)
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TinyTimber, reactive objects in C for real-time embedded systems
- 2008
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Ingår i: Proceedings, Design, Automation and Test in Europe. - New York : ACM Digital Library. - 9783981080131 ; , s. 1382-1385
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Konferensbidrag (refereegranskat)abstract
- Embedded systems are often operating under hard real-time constraints. Such systems are naturally described as time-bound reactions to external events, a point of view made manifest in the high-level programming and systems modeling language Timber. In this paper we demonstrate how the Timber semantics for parallel reactive objects translates to embedded real-time programming in C. This is accomplished through the use of a minimalistic Timber Run-Time system, TinyTimber (TT). The TT kernel ensures state integrity, and performs scheduling of events based on given time-bounds in compliance with the Timber semantics. In this way, we avoid the volatile task of explicitly coding parallelism in terms of processes/threads/semaphores/monitors, and side-step the delicate task to encode time-bounds into priorities. In this paper, the TT kernel design is presented and performance metrics are presented for a number of representative embedded platforms, ranging from small 8-bit to more potent 32-bit micro controllers. The resulting system runs on bare metal, completely free of references to external code (even C-lib) which provides a solid basis for further analysis. In comparison to a traditional thread based real-time operating system for embedded applications (FreeRTOS), TT has tighter timing performance and considerably lower code complexity. In conclusion, TinyTimber is a viable alternative for implementing embedded real-time applications in C today.
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| 5. |
- Magnelöv, Marianne, et al.
(författare)
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Investigation of iron losses during desulphurisation of hot metal utilising nepheline syenite
- 2013
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Ingår i: Ironmaking & steelmaking. - 0301-9233 .- 1743-2812. ; 40:6, s. 436-442
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Tidskriftsartikel (refereegranskat)abstract
- Iron losses during calcium carbide based hot metal desulphurisation have been studied via large scale investigations of slag from the slag pit as well as slag sampling during desulphurisation at SSAB EMEA in Luleå. The desulphurisation slag, after injection of calcium carbide, is normally solid and contains large amounts of iron. An alkali containing mineral, nepheline syenite, was mixed together with the calcium carbide to form a more fluid slag as the iron losses originate from enclosed metal droplets in the slag as well as drawn off hot metal during slag skimming. The slag amount after slag skimming decreased from 28.1 to 25.1 kg t-21 hot metal with addition of 5 wt-% nepheline syenite to the calcium carbide, and the magnetic fraction of the slag from the slag pit decreased from 2.5 to 1.9%. Finally, no negative effect on the reagent efficiency was observed during the trials with addition of nepheline syenite.
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| 6. |
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| 7. |
- Näsman, Mattias, 1989-, et al.
(författare)
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A promised land? : First summary of the research program
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This document lays out the background for the research program “A promised land? Drivers, challenges and opportunities related to the (green) industrialization of Northern Sweden,” (nr. M22-0029) awarded by the Swedish Riksbankens Jubileumsfond’s in 2022. The document summarizes work in progress and may therefore be updated and republished in different versions according to the requirements of the program. This interdisciplinary program aims to understand the economic, social, and political challenges and opportunities of the ongoing industrial transformation in northern Sweden. A key element of the program is to identify drivers, obstacles, and preconditions in a historical, present, and forward-looking process-perspective.
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| 8. |
- Aittamaa, Simon, et al.
(författare)
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Uniform scheduling of internal and external events under SRP-EDF
- 2010
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Ingår i: Annual International Conference on Real-Time and Embedded Systems ( RTES 2010).
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Konferensbidrag (refereegranskat)abstract
- With the growing complexity of modern embedded real-time systems, scheduling and managing of resources has become a daunting task. While scheduling and resource management for internal events can be simplified by adopting a commonplace real-time operating system (RTOS), scheduling and resource management for external events are left in the hands of the programmer, not to mention managing resources across the boundaries of external and internal events. In this paper we propose a unified system view incorporating earliest deadline first (EDF) for scheduling and stack resource policy (SRP) for resource management. From an embedded real-time system view, EDF+SRP is attractive not only because stack usage can be minimized, but also because the cost of a pre-emption becomes almost as cheap as a regular function call, and the number of preemptions is kept to a minimum. SRP+EDF also lifts the burden of manual resource management from the programmer and incorporates it into the scheduler. Furthermore, we show the efficiency of the SRP+EDF scheme, the intuitiveness of the programming model (in terms of reactive programming), and the simplicity of the implementation.
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| 10. |
- Björkman, Bo, et al.
(författare)
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Waste reduction through process optimization and development
- 1996
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Ingår i: JOM. - 1047-4838 .- 1543-1851. ; 48:3, s. 45-49
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Tidskriftsartikel (refereegranskat)abstract
- In this article, the possibilities of optimizing metallurgical processes based on minimization for waste reduction and application requirements for the reuse of waste products are discussed together with the possibilities of treating existing waste in direct connection with the process involved. Some results from ongoing projects on controlled dust generation and an outline of an ongoing research program are also described.
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