| 1. |
- Tjernström, Michael, et al.
(författare)
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The Arctic Summer Cloud Ocean Study (ASCOS) : overview and experimental design
- 2014
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 14:6, s. 2823-2869
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Tidskriftsartikel (refereegranskat)abstract
- The climate in the Arctic is changing faster than anywhere else on earth. Poorly understood feedback processes relating to Arctic clouds and aerosol-cloud interactions contribute to a poor understanding of the present changes in the Arctic climate system, and also to a large spread in projections of future climate in the Arctic. The problem is exacerbated by the paucity of research-quality observations in the central Arctic. Improved formulations in climate models require such observations, which can only come from measurements in situ in this difficult-to-reach region with logistically demanding environmental conditions. The Arctic Summer Cloud Ocean Study (ASCOS) was the most extensive central Arctic Ocean expedition with an atmospheric focus during the International Polar Year (IPY) 2007-2008. ASCOS focused on the study of the formation and life cycle of low-level Arctic clouds. ASCOS departed from Longyearbyen on Svalbard on 2 August and returned on 9 September 2008. In transit into and out of the pack ice, four short research stations were undertaken in the Fram Strait: two in open water and two in the marginal ice zone. After traversing the pack ice northward, an ice camp was set up on 12 August at 87 degrees 21' N, 01 degrees 29' W and remained in operation through 1 September, drifting with the ice. During this time, extensive measurements were taken of atmospheric gas and particle chemistry and physics, mesoscale and boundary-layer meteorology, marine biology and chemistry, and upper ocean physics. ASCOS provides a unique interdisciplinary data set for development and testing of new hypotheses on cloud processes, their interactions with the sea ice and ocean and associated physical, chemical, and biological processes and interactions. For example, the first-ever quantitative observation of bubbles in Arctic leads, combined with the unique discovery of marine organic material, polymer gels with an origin in the ocean, inside cloud droplets suggests the possibility of primary marine organically derived cloud condensation nuclei in Arctic stratocumulus clouds. Direct observations of surface fluxes of aerosols could, however, not explain observed variability in aerosol concentrations, and the balance between local and remote aerosols sources remains open. Lack of cloud condensation nuclei (CCN) was at times a controlling factor in low-level cloud formation, and hence for the impact of clouds on the surface energy budget. ASCOS provided detailed measurements of the surface energy balance from late summer melt into the initial autumn freeze-up, and documented the effects of clouds and storms on the surface energy balance during this transition. In addition to such process-level studies, the unique, independent ASCOS data set can and is being used for validation of satellite retrievals, operational models, and reanalysis data sets.
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| 2. |
- Alfredsson, Magnus, et al.
(författare)
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Funktionskriterier för vägkonstruktioner : Förstudie
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det projekt som här rapporteras har som syfte att identifiera och beskriva de svårigheter och möjligheter som totalentreprenader medför, respektive erbjuder, för alla parter. Målet är att utveckla totalentreprenader på ett sådant sätt att branschens effektivitet ökas. Denna rapport är en förstudie där det studerats vilka krav som byggherren ska ställa på utföraren av en vägkonstruktion i en totalentreprenad med funktionsansvar och hur utföraren ska verifiera kraven. Arbetet har genomförts med medlemmar från olika aktörer i branschen och omfattat främst litteraturstudier och intervjuer. Kunskaper och erfarenheter har sammanställts och analyserats för att slutligen kondenseras ned till ett antal förslag till fortsatt arbete.Förstudien har pekat ut ett antal områden som viktiga för att påskynda framtida utveckling av totalentreprenader:Terminologi – idag råder viss begreppsförvirringAnalys av funktionella krav i tidigare projektTrafikantkravMiljökravUtveckling av funktionella krav i samverkanVäghållarekonomiRegelbetingade begränsningar av funktionella kravUppföljning och underlättande av erfarenhetsackumuleringImplementering av nya mått och mätmetoder
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| 3. |
- Andersson, Jan O., et al.
(författare)
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A genomic survey of the fish parasite Spironucleus salmonicida indicates genomic plasticity among diplomonads and significant lateral gene transfer in eukaryote genome evolution
- 2007
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 8, s. 51-
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Forskningsöversikt (refereegranskat)abstract
- Background: Comparative genomic studies of the mitochondrion-lacking protist group Diplomonadida (diplomonads) has been lacking, although Giardia lamblia has been intensively studied. We have performed a sequence survey project resulting in 2341 expressed sequence tags (EST) corresponding to 853 unique clones, 5275 genome survey sequences (GSS), and eleven finished contigs from the diplomonad fish parasite Spironucleus salmonicida (previously described as S. barkhanus). Results: The analyses revealed a compact genome with few, if any, introns and very short 3′ untranslated regions. Strikingly different patterns of codon usage were observed in genes corresponding to frequently sampled ESTs versus genes poorly sampled, indicating that translational selection is influencing the codon usage of highly expressed genes. Rigorous phylogenomic analyses identified 84 genes - mostly encoding metabolic proteins - that have been acquired by diplomonads or their relatively close ancestors via lateral gene transfer (LGT). Although most acquisitions were from prokaryotes, more than a dozen represent likely transfers of genes between eukaryotic lineages. Many genes that provide novel insights into the genetic basis of the biology and pathogenicity of this parasitic protist were identified including 149 that putatively encode variant-surface cysteine-rich proteins which are candidate virulence factors. A number of genomic properties that distinguish S. salmonicida from its human parasitic relative G. lamblia were identified such as nineteen putative lineage-specific gene acquisitions, distinct mutational biases and codon usage and distinct polyadenylation signals. Conclusion: Our results highlight the power of comparative genomic studies to yield insights into the biology of parasitic protists and the evolution of their genomes, and suggest that genetic exchange between distantly-related protist lineages may be occurring at an appreciable rate in eukaryote genome evolution.
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| 4. |
- Andersson, Staffan, 1952-, et al.
(författare)
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Building performance based on measured data
- 2011
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Ingår i: World Renewable Energy Congress – Sweden, 8–13 May, 2011, Linköping, Sweden. - Linköping : Linköping University Electronic Press. - 9789173930703 ; , s. 899-906
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Konferensbidrag (refereegranskat)abstract
- With increasing liability for builders, the need for evaluation methods that focuses on the building’s performance and thus excludes the impact from residents’ behavior increases. This is not only of interest for new buildings but also when retrofitting existing buildings in order to reduce energy end-use. The investigation in this paper is based on extensive measurements on two fairly representative type of buildings, a single family building in Ekerö, Stockholm built 2000 and two apartment buildings in Umeå (1964) in order to extract key energy performance parameters such as the building’s heat loss coefficient, heat transfer via the ground and heat gained from the sun and used electricity. With access to pre-processed daily data from a 2-month periods, located close to the winter solstice, a robust estimate of the heat loss coefficient was obtained based on a regression analysis. For the single family building the variation was within 1% and for the two heavier apartment buildings an average variation of 2%, with a maximum of 4%, between different analyzed periods close to the winter solstice. The gained heating from the used electricity in terms of a gain factor could not be unambiguously extracted and therefore could only a range for the heat transfer via ground be estimated. The estimated range for the transfer via ground for the two apartment buildings were in very good agreement with those calculated according to EN ISO 13 370 and corresponded to almost 10% of the heating demand at the design temperature. For the single family building with an insulated slab and parts of the walls below ground level, the calculations gave slightly higher transfer than what was obtained from the regression analysis. For the estimated gained solar radiation no comparison has been possible to make, but the estimated gain exhibited an expected correlation with the global solar radiation data that was available for the two apartment buildings.
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| 5. |
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| 6. |
- Berghof, Maria, et al.
(författare)
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Inversion of droplet aerosol analyzer data for long-term aerosol-cloud interaction measurements
- 2014
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 7:4, s. 877-886
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Tidskriftsartikel (refereegranskat)abstract
- The droplet aerosol analyzer (DAA) was developed to study the influence of aerosol properties on clouds. It measures the ambient particle size of individual droplets and interstitial particles, the size of the dry (residual) particles after the evaporation of water vapor and the number concentration of the dry (residual) particles. A method was developed for the evaluation of DAA data to obtain the three-parameter data set: ambient particle diameter, dry (residual) particle diameter and number concentration. First results from in-cloud measurements performed on the summit of Mt. Brocken in Germany are presented. Various aspects of the cloud-aerosol data set are presented, such as the number concentration of interstitial particles and cloud droplets, the dry residue particle size distribution, droplet size distributions, scavenging ratios due to cloud droplet formation and size-dependent solute concentrations. This data set makes it possible to study clouds and the influence of the aerosol population on clouds.
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| 7. |
- Bolling, Anne, et al.
(författare)
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Improving the realism in the VTI driving simulators : Shake final report
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Väg- och transportforskningsinstitutet (VTI) har tre avancerade körsimulatorer med rörelsesystem. Syftet med detta projekt var att utveckla och implementera nya modeller för grafik, vibrationer och buller, allt i syfte att öka realismen för föraren i simulatorn. Vidare skulle en valideringsstudie genomföras. Inom ramen för projektet uppnåddes följande:Utveckling av ett nytt grafiskt programpaket•Förbättring av modellerna för vibrationer på grund av däck/väg•Förbättring av rörelsesystemet genom förskjutning av rotationscentrum•Förbättring av modulen för buller, genom återskapande av däck- och vägbuller.•Synkronisering mellan vägytans grafiska presentation, buller och vibrationer .Modellernas validitet testades i VTI:s simulator III. Statistisk testning av skillnader mellan verklig bil och simulator indikerade absolut validitet för subjektiva bedömningar av vägytans jämnhet och tysthet och för det objektiva måttet hastighet, med undantag av områden där hastighetsgränsen ändrades. I dessa områden erhölls endast relativ validitet eftersom både accelerationer och retardationer var snabbare i simulatorn än i verklig bil. Relativ validitet indikerades också för det subjektiva måttet generell komfort. Resultaten från de olika valideringarna visar att förbättringarna har varit framgångsrika och föraren i simulatorn kan nu se, höra och känna ojämnheter i vägbanan exakt när hjulen träffar dessa. Fortfarande återstår dock många möjligheter till ytterligare förbättringar i simulatormodellerna.
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| 8. |
- Bolling, Anne, et al.
(författare)
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SHAKE - an approach for realistic simulation of rough roads in a moving base driving simulator
- 2010
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Ingår i: Trends in driving simulation design and experiments. - Arcueil : Institut national de recherche sur les transports et leur securite, INRETS. - 9782857826859 ; , s. 135-143
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Konferensbidrag (refereegranskat)abstract
- With today’s advanced measurement equipment for measuring roads, it is possible to measure road geometry at high precision within a large span of wavelengths. Detailed information about the roads longitudinal and lateral profile, including macro texture, would in theory be sufficient for a realistic reproduction of road induced vibration and noise in a driving simulator. Especially, it would be possible to create a direct connection between the visual information of the road condition and the ride experience, which would increase the level of realism in the simulation. VTI has during three years performed an internal project called SHAKE with the aim to develop and implement models in VTI driving simulator III that use measured road data for generating realistic vibrations and audible road noise connected to the visual impression presented on the projection screen. This has indeed resulted in an more realistic driving experience, and a validation study with test persons driving both in the simulator and in the field has been undertaken. The OpenDRIVE standard is used as a framework for describing the road properties (e.g. visual, vibrations and noise). For this purpose some augumentations to the OpenDRIVE standard had to be made. This paper describes the technical implementations in the driving simulator, along with results from test drives on the implemented road sections
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| 9. |
- Bram, Staffan, et al.
(författare)
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STM BALTSAFE : Validation of WP4 : Document No: BS_ WP6.2.2
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vessel Traffic Service Operators (VTSOs) employ their experience and problem-solving skills in order to uphold safety in the controlled traffic area. Human Factors studies focus on the conditions of that work – whether technologies, organizations and interfaces to other stakeholders are adapted to VTS operator activities and needs. For the VTS, the purpose of Sea Traffic Management (STM) services is to allow digital communication and information sharing between the VTS Centre and ships in the controlled area, with an emphasis on simple creation and sharing of ship routes. The aim of this evaluation has been to uncover Human Factors hazards associated with the introduction of STM services developed in STM BALT SAFE WP4, directed towards route creation, sharing and associated safety functions. Analyses have concentrated on three levels of interaction within the sea traffic system: 1. The VTS operator and her immediate working environment (usability and ergonomics of VTS systems and tools affected by STM implementation). 2. The organization of VTS collaboration with other actors in the port and its surroundings. 3. Interaction in the greater context of ship traffic (including both STM and non-STM ships). The evaluation was performed using qualitative methods in a process consisting of three main stages – A first analysis using heuristics from the domain of Human Reliability Analysis, an interview study with sea traffic system stakeholders, and a VTS simulator study. Results indicate that maritime administrations should employ a consistent design process that caters for local VTS Centre characteristics and the needs of their operators. As work with STM continues, technical development should be augmented with an iterative development of VTS system user experience and usability. Aspects of STM that are already known to require a human factors validation are, but not limited to: • That the new information provided to operators through the STM services is presented in a way that does not introduce confusion or obscure information (e.g. cluttering of routes, poor visibility of ships/routes/geographical features). • That alarms and/or alerts are relevant, useful and communicated effectively. Irrelevant alarms or alerts can disturb the work of the VTSO, and even if only relevant alerts are provided, the sum of all alerts can still produce a poor working environment (e.g. with regard to noise). • That STM services are coupled with sufficient support for notetaking and/or marking. With a larger bulk of information available to the operator (e.g. around possible future hazards) comes a larger need to support the operator attention and memory. • That the implementation of STM functions accounts for information management over several work shifts. • That predictive tools (e.g. prediction of future ship movements and associated conflicts) factor in prediction uncertainty, so that the operator is given a truthful representation of possible traffic development. • That there are means of communication suitable for use with the STM functions. Even though chat functionality was excluded from the STM BALT SAFE scope, some informants hold that other means of communication than VHF might be necessary if the ship is to send its route before reaching the VTS area. • That dynamics in VTS-ship interaction may be affected as new forms of communication develop. For example, even if the purpose of the VTS Centre is only to “inform” ships about traffic conditions, creating and sharing routes via STM services might be regarded as something more than a friendly suggestion. This invokes a discussion around VTS authority and responsibility in the event of an incident that needs to be continued. Evaluation data suggests that the use of STM functionality is not appropriate for all operative conditions, and that implementation must be calibrated against the practical needs of local VTS operators. Here, a balance must be struck between allowing for local adaption of STM services and offering a uniform STM interface towards vessels moving between different control areas. A final aspect of adaptation is the relation between VTS technical functionality and how these functionalities are put to practical use. Seeing that STM services could expand the operator time horizon and allow them to work more proactively, technical development should be combined with a review of local VTS procedures, making sure that the VTS operational approach (e.g. procedures for ship interaction or the functional level of VTS implementation) matches all the capabilities afforded by STM.
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| 10. |
- Fors, Erik, et al.
(författare)
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Development of an H-TDMA for long-term unattended measurement of the hygroscopic properties of atmospheric aerosol particles
- 2009
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 2:1, s. 313-318
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Tidskriftsartikel (refereegranskat)abstract
- A new hygroscopic tandem differential mobility analyzer (H-TDMA) has been constructed at Lund University within the frameworks of the EU FP6 Infrastructure Project EUSAAR (www.eusaar.org). The aim of this coordinated H-TDMA development is to design and evaluate a new generation of H-TDMAs that are capable of conducting long term measurements of the hygroscopic growth and state of mixing of sub-micrometer atmospheric aerosol particles at the EUSAAR aerosol super-sites across Europe. The H-TDMA constructed for this project has been validated with respect to hygroscopic growth factor, stability of relative humidity (RH), temperature stability and its ability to operate unattended for longer periods of time. When measuring growth factors of ammonium sulphate, the new H-TDMA system was found to measure within a growth factor deviation of +/- 0.05 compared to previously recorded data by Tang et al. (1994). The long term RH of the system has been found stable at 90.0% with a standard deviation of +/- 0.23% and an average temperature variability of the second DMA less than +/- 0.1 K. Daily automated ammonium sulphate measurements have validated the ambient measurements. The instrument is operated at the EMEP/EUSAAR background station Vavihill in the southern part of Sweden.
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