| 1. |
- Hansson, Jörgen, et al.
(författare)
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Clearance of Flight Control Laws for Time-Varying Parameters
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this article exponential stability of the closed loop for the Saab AB VEGAS model controlled by a gain-scheduled linear fractional transformation controller is investigated for time-varying Mach-number. The analysis is based on parameter-dependent Lyapunov-functions which are obtained by investigating feasibility of linear matrix inequalities.
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| 2. |
- Ståhl Gunnarsson, Karin, et al.
(författare)
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Clearance of Flight Control Laws using Linear Fractional Transformations
- 2004
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Ingår i: Proceedings of the 2004 AIAA Guidance, Navigation and Control Conference and Exhibit. - Reston, Virigina : American Institute of Aeronautics and Astronautics. - 9781624100734
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Konferensbidrag (refereegranskat)abstract
- The problem of flight clearance of linear stability requirements in the complete flight evelope is studied. The approach is to use mu-analysis of linear fractional transformations description of the system dynamics augmented with an uncertainty model of the clearance criteria. Two methods to derive the linear fractional transformations are used and compared: the Trends and Bands method and rational approximations. The two approaches are applied to a UAV demostrator model. The resulting models are analyzed by mu-sensitivites in order to demonstrate how this can be used to reduce the order of the linear fractional transformations description. A number of algorithms to compute upper and lower bounds on mu are also compared. Results from applying the clearance criteria to the UAV demonstrator model are given.
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| 3. |
- Maia De Souza, Danielle, et al.
(författare)
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Ecosystem services in life cycle assessment: A synthesis of knowledge and recommendations for biofuels
- 2018
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Ingår i: Ecosystem Services. - : Elsevier BV. - 2212-0416. ; 30, s. 200-210
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Forskningsöversikt (refereegranskat)abstract
- There is an increasing trend in promoting the use of biofuels for transportation as a low-fossil carbon energy source, but little knowledge on their multidimensional environmental impacts. Whole-system approaches, such as life cycle assessment (LCA), have been extensively employed to analyze the environmental performance of different biofuels. However, it remains unclear to which extent biofuels impact ecosystems and the services they provide, in particular related to different management practices. To overcome this challenge, this paper draws recommendations to better holistically address ecosystem services (ES) in LCA, with a focus on biofuels. We first pinpoint some of the challenges in accounting for the concept of ES in decision-making and review some of the existing ES classification frameworks and the usefulness of the cascade model. Second, we discuss the implications of identified context-specific aspects on the modeling of biofuel production impacts on ES in LCA. Finally, we propose a conceptual framework to link ES classification systems, the cascade model and the LCA approach. Although some challenges still remain unsolved, due to the existing life cycle impact assessment structure, existing ES frameworks and the cascade model are helpful tools to better include ES into LCA of different biofuels.
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| 4. |
- Björnberg, Karin Edvardsson, et al.
(författare)
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Preface
- 2022
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Ingår i: The Vision Zero Handbook: Theory, Technology and Management for a Zero Casualty Policy. - Cham : Springer International Publishing. ; , s. v-vi
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Globally, about 1.3 million people die every year in road traffic crashes and about 50 million are injured. For long, the death toll on roads was considered to be a necessary price that we have to pay for our mobility and development. But beginning in the late 1990s, an alternative approach to road safety has become more and more influential. The Vision Zero movement declares that every severe crash in road traffic is an avoidable failure and that no other goal is satisfactory than zero fatalities and serious injuries. This is by no means a new idea. Similar views have been expressed in many other areas of safety management. Safety work based on the idea that every accident is one too much can be found in workplace safety, fire safety, aviation, suicide prevention, patient safety, infection control, and many other areas. Zero goals are also gaining traction in environmental protection and sustainable development work. Terms such as zero waste, zero emissions, zero carbon, and zero poverty have become increasingly important in climate and environmental policies. Detractors claim that Vision Zero is too stringent and therefore also unrealistic. But practical experience has shown again and again that the Vision Zero approach can efficiently reduce the number of deaths and serious injuries. Of course, it is not enough to set up Vision Zero as a goal. Its effects materialize when it is systematically applied, and every serious accident is treated as a failure that must not be repeated. This handbook is the first comprehensive collection of knowledge and experience of Vision Zero. Its contributing authors are experts from all around the world, representing a wide range of academic disciplines and an equally wide range of specializations in practical safety management.
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| 5. |
- Hansson, Karin, et al.
(författare)
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Reputation, inequality and meeting techniques : visualising user hierarchy to support collaboration
- 2014
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Ingår i: Computational and mathematical organization theory. - : Springer Science and Business Media LLC. - 1381-298X .- 1572-9346. ; 20:2, s. 155-175
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Tidskriftsartikel (refereegranskat)abstract
- Equality within groups is ordinarily taken for granted when technology for e-democracy is conceived and developed. However, inequality in online communication is just as common as in other social contexts. Therefore, we have developed a groupware with the express purpose of illuminating imbalance of power. Inequalities are measured and made visible to users of the system, and they change dynamically as actions are taken by users. The system is based on democratic meeting techniques and is reminiscent of a strategy game based on social media. Each participant’s score within the game is dynamically calculated and reflects that user’s activity, others’ reactions to that activity and reactions to others’ activities. The calculations and weighing mechanisms are open to inspection and change by the users, and hierarchical roles reflecting game levels may be attached to system rights belonging to individual users and user groups. The prototype we present stems from the question of how to conceive of groupware based on diversity and is the result of combining social theory with algorithms for modelling and visualising user hierarchy and status. Empirical user tests suggest improvements to the prototype’s interface, which will be implemented and further evaluated by embedding the algorithms in a system for e-participation.
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| 6. |
- Höglund, Jonas, et al.
(författare)
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Biofuels and land use in Sweden: an overview of land-use change effects
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Supported by policies, biofuel production has been continuously increasing worldwide during recent years. However, concerns have been raised that biofuels, often advocated as the future substitute for greenhouse gas (GHG) intensive fossil fuels, may cause negative effects on the climate and the environment. When assessing GHG emissions from biofuels, the production phase of the biofuel crop is essential since this is the phase in which most of the GHG emissions occur during the life cycle of the fuel, often linked to land use and land management. Changes in land use can result from a wide range of anthropogenic activities including agriculture and forestry management, livestock and biofuel production. The report first presents a review of the literature in the different scientific areas related to land use change (LUC) and biofuel production. Knowledge gaps related to LUC is compiled and, a synthesis is developed highlighting major challenges and key findings. Main findings are that (i) deforestation, forest management, and climate change deforestation is a major contributor to GHG emissions and can contribute to soil erosion and carbon stock changes, (ii) albedo changes and the timing of emissions need to be better understood, (iii) to avoid degradation of biodiversity great care must be taken to develop sustainable biofuel production (iv) nutrient leakage and removal of forest residues can influence the biomass growth potential (v) to avoid fertility losses in agricultural soils during biofuel production, crops with low fertilizer needs, high nutrient use efficiency and high yields should be given priority (vi) indirect effects on land use are extremely complex to quantify without great uncertainty (vii) biofuels contribution to rising food prices and poverty even more challenging (viii) biofuel production can create jobs but also interfere with traditional ways of life and recreational values, (ix) to avoid negative effects, biofuel production should be developed in collaboration with the stakeholders involved: farmers, land owners, tourists, and industry. The literature review and synthesis presented in this report shows that land use on this planet is already placing high stress on ecosystems, atmosphere, soils and human life. Because of increased biofuel production, land use change is therefore at risk of aggravating these problems. Conclusions drawn are that the LUC caused by increasing use of biofuels can be negative to various degrees but that drawbacks can be mitigated through policy measures or technology developments. Examples include the cultivation of high-yielding crops, cultivation on abandoned arable land, and effective use of by-products and waste. To explore the opportunities that exist for beneficial land use change, continued responsible and sensitive collaboration between industry, policy-makers, researchers and local communities is a prerequisite.
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| 7. |
- Bidleman, Terry, et al.
(författare)
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Atmospheric pathways of chlorinated pesticides and natural bromoanisoles in the northern Baltic Sea and its catchment
- 2015
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 44, s. 472-483
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Tidskriftsartikel (refereegranskat)abstract
- Long-range atmospheric transport is a major pathway for delivering persistent organic pollutants to the oceans. Atmospheric deposition and volatilization of chlorinated pesticides and algae-produced bromoanisoles (BAs) were estimated for Bothnian Bay, northern Baltic Sea, based on air and water concentrations measured in 2011-2012. Pesticide fluxes were estimated using monthly air and water temperatures and assuming 4 months ice cover when no exchange occurs. Fluxes were predicted to increase by about 50 % under a 2069-2099 prediction scenario of higher temperatures and no ice. Total atmospheric loadings to Bothnian Bay and its catchment were derived from air-sea gas exchange and bulk'' (precipitation ? dry particle) deposition, resulting in net gains of 53 and 46 kg year(-1) for endosulfans and hexachlorocyclohexanes, respectively, and net loss of 10 kg year(-1) for chlordanes. Volatilization of BAs releases bromine to the atmosphere and may limit their residence time in Bothnian Bay. This initial study provides baseline information for future investigations of climate change on biogeochemical cycles in the northern Baltic Sea and its catchment.
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| 8. |
- Hansson, Boel, et al.
(författare)
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Subjectively Reported Effects Experienced in an Actively Shielded 7T MRI: A Large-Scale Study.
- 2020
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Ingår i: Journal of magnetic resonance imaging : JMRI. - : Wiley. - 1522-2586 .- 1053-1807. ; 52:4, s. 1265-1276
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Tidskriftsartikel (refereegranskat)abstract
- Ultrahigh-field (UHF) MRI advances towards clinical use. Patient compliance is generally high, but few large-scale studies have investigated the effects experienced in 7T MRI systems, especially considering peripheral nerve stimulation (PNS) and caregiving.To evaluate the quantity, the intensity, and subjective experiences from short-term effects, focusing on the levels of comfort and compliance of subjects.Prospective.In all, 954 consecutive MRIs in 801 subjects for 3years.7T.After the 7T examination, a questionnaire was used to collect data.Descriptive statistics, Spearman's rank correlation, Mann-Whitney U-test, and t-test.The majority (63%) of subjects agreed that the MRI experience was comfortable and 93% would be willing to undergo future 7T MRI as a patient (5% undecided) and 82% for research purposes (12% undecided). The most common short-term effects experienced were dizziness (81%), inconsistent movement (68%), PNS (63%), headache (40%), nausea (32%), metallic taste (12%), and light flashes (8%). Of the subjects who reported having PNS (n = 603), 44% experienced PNS as "not uncomfortable at all," 45% as "little or very little uncomfortable," and 11% as "moderate to very much uncomfortable." Scanner room temperature was experienced more comfortable before (78%) than during (58%) examinations, and the noise level was acceptable by 90% of subjects. Anxiety before the examination was reported by 43%. Patients differed from healthy volunteers regarding an experience of headache, metallic taste, dizziness, or anxiety. Room for improvement was pointed out after 117 examinations concerning given information (n = 73), communication and sound system (n = 35), or nursing care (n = 15).Subjectively reported effects occur in actively shielded 7T MRI and include physiological responses and individual psychological issues. Although leaving room for improvement, few subjects experienced these effects being so uncomfortable that they would lead to aversion to future UHF examinations.1 TECHNICAL EFFICACY: Stage 5.
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| 9. |
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| 10. |
- Mattsson, Karin, et al.
(författare)
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Altered Behavior, Physiology, and Metabolism in Fish Exposed to Polystyrene Nanoparticles
- 2015
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 49:1, s. 553-561
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Tidskriftsartikel (refereegranskat)abstract
- The use of nanoparticles in consumer products, for example, cosmetics, sunscreens, and electrical devices, has increased tremendously over the past decade despite insufficient knowledge about their effects on human health and ecosystem function. Moreover, the amount of plastic waste products that enter natural ecosystems, such as oceans and lakes, is increasing, and degradation of the disposed plastics produces smaller particles toward the nano scale. Therefore, it is of utmost importance to gain knowledge about how plastic nanoparticles enter and affect living organisms. Here we have administered 24 and 27 nm polystyrene nanoparticles to fish through an aquatic food chain, from algae through Daphnia, and studied the effects on behavior and metabolism. We found severe effects on feeding and shoaling behavior as well as metabolism of the fish; hence, we conclude that polystyrene nanoparticles have severe effects on both behavior and metabolism in fish and that commonly used nanosized particles may have considerable effects on natural systems and ecosystem services derived from them.
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