| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Lohstroh, Marten, et al.
(författare)
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Logical Time for Reactive Software
- 2023
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Ingår i: Proceedings of 2023 Cyber-Physical Systems and Internet-of-Things Week, CPS-IoT Week 2023. - : Association for Computing Machinery (ACM). ; , s. 313-318
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Konferensbidrag (refereegranskat)abstract
- Timing is an essential feature of reactive software. It is not just a performance metric, but rather forms a core part of the semantics of programs. This paper argues for a notion of logical time that serves as an engineering model to complement a notion of physical time, which models the physical passage of time. Programming models that embrace logical time can provide deterministic concurrency, better analyzability, and practical realizations of timing-sensitive applications. We give definitions for physical and logical time and review some languages and formalisms that embrace logical time.
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| 3. |
- Bartholomay, S., et al.
(författare)
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Cross-talk compensation for blade root flap-and edgewise moments on an experimental research wind turbine and comparison to numerical results
- 2018
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Ingår i: Proceedings of the ASME Turbo Expo. - : ASME Press. - 9780791851180
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Konferensbidrag (refereegranskat)abstract
- In the current paper a method to correct cross-talk effects for strain-gauge measurements is presented. Themethod is demonstrated on an experimental horizontal axiswind turbine. The procedure takes cross-moments (flapwise on edgewise moments and vice versa) as well as axialacceleration into account. The results from the experimental setup are compared to numerical URANS calculationsand the medium-fidelity code Qblade for a baseline caseand two yawed inflow situations.
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| 4. |
- Cremona, Fabio, et al.
(författare)
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Hybrid co-simulation : it's about time
- 2019
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Ingår i: Software and Systems Modeling. - : Springer Nature. - 1619-1366 .- 1619-1374. ; 18:3, s. 1655-1679
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Tidskriftsartikel (refereegranskat)abstract
- Model-based design methodologies are commonly used in industry for the development of complex cyber-physical systems (CPSs). There are many different languages, tools, and formalisms for model-based design, each with its strengths and weaknesses. Instead of accepting some weaknesses of a particular tool, an alternative is to embrace heterogeneity, and to develop tool integration platforms and protocols to leverage the strengths from different environments. A fairly recent attempt in this direction is the functional mock-up interface (FMI) standard that includes support for co-simulation. Although this standard has reached acceptance in industry, it provides only limited support for simulating systems that mix continuous and discrete behavior, which are typical of CPS. This paper identifies the representation of time as a key problem, because the FMI representation does not support well the discrete events that typically occur at the cyber-physical boundary. We analyze alternatives for representing time in hybrid co-simulation and conclude that a superdense model of time using integers only solves many of these problems. We show how an execution engine can pick an adequate time resolution, and how disparities between time representations internal to co-simulated components and the resulting effects of time quantization can be managed. We propose a concrete extension to the FMI standard for supporting hybrid co-simulation that includes integer time, automatic choice of time resolution, and the use of absent signals. We explain how these extensions can be implemented modularly within the frameworks of existing simulation environments.
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| 5. |
- Rockström, Johan, et al.
(författare)
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A safe operating space for humanity
- 2009
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 461:7263, s. 472-475
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Rockström, Johan, et al.
(författare)
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Planetary Boundaries : Exploring the Safe Operating Space for Humanity
- 2009
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Ingår i: Ecology & Society. - 1708-3087. ; 14:2, s. 32-
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems. We have identified nine planetary boundaries and, drawing upon current scientific understanding, we propose quantifications for seven of them. These seven are climate change (CO2 concentration in the atmosphere <350 ppm and/or a maximum change of +1 W m(-2) in radiative forcing); ocean acidification (mean surface seawater saturation state with respect to aragonite >= 80% of pre-industrial levels); stratospheric ozone (<5% reduction in O-3 concentration from pre-industrial level of 290 Dobson Units); biogeochemical nitrogen (N) cycle (limit industrial and agricultural fixation of N-2 to 35 Tg N yr(-1)) and phosphorus (P) cycle (annual P inflow to oceans not to exceed 10 times the natural background weathering of P); global freshwater use (<4000 km(3) yr(-1) of consumptive use of runoff resources); land system change (<15% of the ice-free land surface under cropland); and the rate at which biological diversity is lost (annual rate of <10 extinctions per million species). The two additional planetary boundaries for which we have not yet been able to determine a boundary level are chemical pollution and atmospheric aerosol loading. We estimate that humanity has already transgressed three planetary boundaries: for climate change, rate of biodiversity loss, and changes to the global nitrogen cycle. Planetary boundaries are interdependent, because transgressing one may both shift the position of other boundaries or cause them to be transgressed. The social impacts of transgressing boundaries will be a function of the social-ecological resilience of the affected societies. Our proposed boundaries are rough, first estimates only, surrounded by large uncertainties and knowledge gaps. Filling these gaps will require major advancements in Earth System and resilience science. The proposed concept of "planetary boundaries" lays the groundwork for shifting our approach to governance and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative externalities, toward the estimation of the safe space for human development. Planetary boundaries define, as it were, the boundaries of the "planetary playing field" for humanity if we want to be sure of avoiding major human-induced environmental change on a global scale.
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