| 1. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 2. |
- Harrie, L., et al.
(författare)
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Introduktion till geografisk informationsbehandling
- 2020. - 7
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Ingår i: Geografisk informationsbehandling : teori, metoder och tillämpningar. - 9789144131740 ; , s. 19-37
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Bokkapitel (refereegranskat)abstract
- Summary: Geografisk informationsbehandling baseras på insamling, lagring, analys och visualisering av geografiska data. Denna indelning utgör också grunden för bokens disposition. Boken är i första hand avsedd för introducerande kurser vid universitet och högskolor men vissa delar är lämpliga även på avancerad nivå. Den är också utmärkt för yrkesverksamma inom GIS som vill öka sina teoretiska kunskaper. Boken innehåller både teoretiska och praktiska delar, där de senare beskriver tillämpningar som exempelvis samhällsplanering, miljöövervakning och kommersiella tjänster. I insamlingsdelen beskrivs hur man anger en position genom att koppla ett koordinatsystem till jordytan. Därefter beskrivs de vanligaste metoderna att samla in geografiska data som satellitbaserade positioneringssystem, flygfotografering, satellitbaserad fjärranalys och laserskanning. Lagringsdelen behandlar hur dessa data lagras i databaser och distribueras via webben. Analysdelen innehåller beskrivningar av de vanligaste analysmetoderna samt kvalitetsfrågor. Resultatet av en geografisk analys visualiseras oftast i form av kartor, vilket är temat för den sista delen av boken. Denna sjunde upplaga har uppdaterats med nya aktuella tillämpningsexempel. Dessa är i denna upplaga beskrivna tillsammans med de teoretiska beskrivningarna för att stärka kopplingen mellan teori och tillämpningar. Dessutom har beskrivningen av webbtillämpningar utökats och utgör nu ett eget kapitel, och även texten om webbvisualiseringar har stärkts i kartografikapitlet. Vidare har det tillkommit beskrivningar av nya mättekniker samt texter om lagring, analys och visualisering av 3D geografiska data.
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| 3. |
- Lembrechts, Jonas J., et al.
(författare)
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Global maps of soil temperature
- 2022
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 28:9, s. 3110-3144
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Tidskriftsartikel (refereegranskat)abstract
- Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean=3.0±2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6±2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7±2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.
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| 4. |
- Lohse, M., et al.
(författare)
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Evaluating extrovert and introvert behaviour of a domestic robot – a video study
- 2008
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Ingår i: Proceedings of the 17th IEEE International Symposium on Robot and Human Interactive Communication, RO-MAN. - New York : IEEE. - 9781424422128 ; , s. 488-493
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Konferensbidrag (refereegranskat)abstract
- Human-Robot Interaction (HRI) research is here presented into social robots that have to be able to interact with inexperienced users. In the design of these robots many research findings of human-human interaction and human-computer interaction are adopted but the direct applicability of these theories is limited because a robot is different from both humans and computers. Therefore, new methods have to be developed in HRI in order to build robots that are suitable for inexperienced users. In this paper we present a video study we conducted employing our robot BIRON (BIelefeld RObot companioN) which is designed for use in domestic environments. Subjects watched the system during the interaction with a human and rated two different robot behaviours (extrovert and introvert). The behaviours differed regarding verbal output and person following of the robot. Aiming to improve human-robot interaction, participants' ratings of the behaviours were evaluated and compared.
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| 5. |
- Sjöström, Martin, et al.
(författare)
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Exploring the potential of MODIS EVI for modeling gross primary production across African ecosystems
- 2011
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Ingår i: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257. ; 115:4, s. 1081-1089
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Tidskriftsartikel (refereegranskat)abstract
- One of the most frequently applied methods for integrating controls on primary production through satellite data is the light use efficiency (LUE) approach, which links vegetation gross or net primary productivity (GPP or NPP) to remotely-sensed estimates of absorbed photosynthetically active radiation (APAR). Eddy covariance towers provide continuous measurements of carbon flux, presenting an opportunity for evaluation of satellite estimates of GPP. Here we investigate relationships between eddy covariance estimated GPP, environmental variables and the enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) across African savanna ecosystems. EVI was found to correlate well with estimated GPP on a site-by-site basis. Combining EVI with tower-measured PAR and evaporative fraction (EF, a measure of water sufficiency) improved the direct relationship between GPP and EVI at the majority of the sites. The slope of this relationship was strongly related to site peak leaf area index (LAI). These results are promising for the extension of GPP through the use of remote sensing data to a regional or even continental scale.
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| 6. |
- Walters, M. L., et al.
(författare)
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Evaluating the Robot Personality and Verbal Behavior of Domestic Robots Using Video-Based Studies
- 2014
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Ingår i: Household Service Robotics. - : Elsevier. - 9780128009437 ; , s. 467-486
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Robots are increasingly being used in domestic environments and should be able to interact with inexperienced users. Human-human interaction and human-computer interaction research findings are relevant, but often limited because robots are different from both humans and computers. Therefore, new human-robot interaction (HRI) research methods can identify the design of robots suitable for inexperienced users. A video-based HRI (VHRI) methodology was used to carry out a multi-national HRI user study for the prototype domestic robot BIRON (BIelefeld RObot companioN). Previously, the VHRI methodology was used in constrained HRI situations, while in this study HRIs involved a series of events as part of a "home tour" scenario. Thus, the present chapter is the first study of this methodology in extended HRI contexts with a multi-national approach. Participants watched videos of the robot interacting with a human actor and rated two robot behaviors (Extrovert and Introvert). Participants' perceptions and ratings of the robot's behaviors differed with regard to both verbal interactions and person following by the robot. The study also confirms that the VHRI methodology provides a valuable means to obtain early user feedback, even before fully working prototypes are available. This can usefully guide the future design studies on robots, and associated verbal and non-verbal behaviors.
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| 7. |
- Abdi, A. M., et al.
(författare)
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First assessment of the plant phenology index (PPI) for estimating gross primary productivity in African semi-arid ecosystems
- 2019
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Ingår i: International Journal of Applied Earth Observation and Geoinformation. - : Elsevier BV. - 1569-8432. ; 78, s. 249-260
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Tidskriftsartikel (refereegranskat)abstract
- The importance of semi-arid ecosystems in the global carbon cycle as sinks for CO 2 emissions has recently been highlighted. Africa is a carbon sink and nearly half its area comprises arid and semi-arid ecosystems. However, there are uncertainties regarding CO 2 fluxes for semi-arid ecosystems in Africa, particularly savannas and dry tropical woodlands. In order to improve on existing remote-sensing based methods for estimating carbon uptake across semi-arid Africa we applied and tested the recently developed plant phenology index (PPI). We developed a PPI-based model estimating gross primary productivity (GPP) that accounts for canopy water stress, and compared it against three other Earth observation-based GPP models: the temperature and greenness (T-G) model, the greenness and radiation (GöR) model and a light use efficiency model (MOD17). The models were evaluated against in situ data from four semi-arid sites in Africa with varying tree canopy cover (3–65%). Evaluation results from the four GPP models showed reasonable agreement with in situ GPP measured from eddy covariance flux towers (EC GPP) based on coefficient of variation (R 2 ), root-mean-square error (RMSE), and Bayesian information criterion (BIC). The GöR model produced R 2 = 0.73, RMSE = 1.45 g C m −2 d −1 , and BIC = 678; the T-G model produced R 2 = 0.68, RMSE = 1.57 g C m −2 d −1 , and BIC = 707; the MOD17 model produced R 2 = 0.49, RMSE = 1.98 g C m −2 d −1 , and BIC = 800. The PPI-based GPP model was able to capture the magnitude of EC GPP better than the other tested models (R 2 = 0.77, RMSE = 1.32 g C m −2 d −1 , and BIC = 631). These results show that a PPI-based GPP model is a promising tool for the estimation of GPP in the semi-arid ecosystems of Africa.
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| 8. |
- Bolin, David, 1983, et al.
(författare)
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Fast estimation of spatially dependent temporal vegetation trends using Gaussian Markov random fields
- 2009
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Ingår i: Computational Statistics and Data Analysis. - : Elsevier BV. - 0167-9473. ; 53:8, s. 2885-2896
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for efficient methods for estimating trends in spatio-temporal Earth Observation data. A suitable model for such data is a space-varying regression model, where the regression coefficients for the spatial locations are dependent. A second order intrinsic Gaussian Markov Random Field prior is used to specify the spatial covariance structure. Model parameters are estimated using the Expectation Maximisation (EM) algorithm, which allows for feasible computation times for relatively large data sets. Results are illustrated with simulated data sets and real vegetation data from the Sahel area in northern Africa. The results indicate a substantial gain in accuracy compared with methods based on independent ordinary least squares regressions for the individual pixels in the data set. Use of the EM algorithm also gives a substantial performance gain over Markov Chain Monte Carlo-based estimation approaches. © 2008 Elsevier B.V. All rights reserved.
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| 9. |
- Eklundh, L., et al.
(författare)
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Automatisk skadeklassning av lovtrad i stadsbebyggelse med hjalp av digitaliserade IR-fargflygbilder
- 1987
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Ingår i: Svensk Geografisk Arsbok. - 0081-9808. ; 63, s. 228-242
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Tidskriftsartikel (refereegranskat)abstract
- In August 1986 some parks in central Malmo were photographed from a height of 760 meters with colour infrared film. Two simultaneous studies were performed to evaluate the feasibility of manual and digital classification of trees with different degrees of crown damage. This damage is mostly due to exhaustion fumes from heavily trafficked roads, mechanical damage to roots and de-icing salt. This paper describes the method and results of the digital classification and compares the results with the manual interpretation. -English summary
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| 10. |
- Eklundh, L.
(författare)
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Tillförlitlig global vegetationsinformation fran satellitdata-optimism eller realitet?
- 1997
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Ingår i: Svensk Geografisk Arsbok. - 0081-9808. ; 73, s. 7-15
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Tidskriftsartikel (refereegranskat)abstract
- The continuous operation of the NOAA series of meteorological satellites from the early 1980s onward, and the use of time series of data from its AVHRR sensor have been instrumental in the development of a new paradigm in the area of global earth observation. The coarse spatial and high temporal resolution of the data contrasts sharply with the data characteristics of traditional earth resource satellites, such as Landsat and SPOT, with their high spatial and low temporal resolution. Numerous scientists have demonstrated the potential of the data for capturing seasonal variations in terrestrial vegetation. The enthusiam of researchers has led them to use time series of ANHRR data for almost every conceivable type of study, from mapping of deserts and forests to the monitoring of ecological conditions for locust infestations and the spread of malaria by mosquitoes, AVHRR data are not being used operationally in programmes issuing early warnings for drought and famine in semi-arid areas. However, studies of the quality of the data cast some doubts over previous optimism. How do we come to terms with the contradictory results and what are the implications for the future use of the data?.
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