| 1. |
- Bellm, Eric C., et al.
(författare)
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The Zwicky Transient Facility : System Overview, Performance, and First Results
- 2019
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Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 131:995
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Tidskriftsartikel (refereegranskat)abstract
- The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg(2) field of view and 8 s readout time, yielding more than an order of magnitude improvement in survey speed relative to its predecessor survey, the Palomar Transient Factory. We describe the design and implementation of the camera and observing system. The ZTF data system at the Infrared Processing and Analysis Center provides near-real-time reduction to identify moving and varying objects. We outline the analysis pipelines, data products, and associated archive. Finally, we present on-sky performance analysis and first scientific results from commissioning and the early survey. ZTF's public alert stream will serve as a useful precursor for that of the Large Synoptic Survey Telescope.
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| 2. |
- Ye, Quanzhi, et al.
(författare)
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Toward Efficient Detection of Small Near-Earth Asteroids Using the Zwicky Transient Facility (ZTF)
- 2019
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Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 131:1001
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Tidskriftsartikel (refereegranskat)abstract
- We describe ZStreak, a semi-real-time pipeline specialized in detecting small, fast-moving, near-Earth asteroids (NEAs), which is currently operating on the data from the newly commissioned Zwicky Transient Facility (ZTF) survey. Based on a prototype originally developed by Waszczak et al. (2017) for the Palomar Transient Factory (PTF), the predecessor of ZTF, ZStreak features an improved machine-learning model that can cope with the 10x data rate increment between PTF and ZTF. Since its first discovery on 2018 February 5 (2018 CL), ZTF/ZStreak has discovered 45 confirmed new NEAs over a total of 232 observable nights until 2018 December 31. Most of the discoveries are small NEAs, with diameters less than similar to 100. m. By analyzing the discovery circumstances, we find that objects having the first to last detection time interval under 2. hr are at risk of being lost. We will further improve real-time follow-up capabilities, and work on suppressing false positives using deep learning.
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| 3. |
- Alayon Glazunov, Andres, et al.
(författare)
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Impact of Scattering Within a Multipath Simulator Antenna Array on the Ricean Fading Distribution Parameters in OTA Testing
- 2014
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 62:6, s. 3257-3269
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate the unwanted scattering that exists within the multipath simulator (MPS) array antennas employed in over the air (OTA) testing of mobile terminals. The impact of scattering is evaluated in terms of the measurement uncertainty of the average received power and the Ricean K-factor. The maximum ratio combining diversity is investigated for a generic device under test comprising two half-wavelength dipole antennas. We provide closed-form expressions for the uncertainties of the average received power and the Ricean K-factor for a uniform circular array of MPS antennas and a 2-D uniformly distributed angle-of-arrival spectrum. We also derive the maximum number of MPS antennas and the minimum ring radius of the MPS system as a function of the separation between the most distant antenna elements if the device under test employs a uniform linear array. As a result, we provide design guidelines for MPS array in terms of the number antennas, the radius of the MPS array and the wavelength of the carrier frequency.
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| 4. |
- Arvidsson, Niklas, et al.
(författare)
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Cirkulära möbelflöden : Hur nya affärsmodeller kan bidra till hållbar utveckling inom offentliga möbler
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sverige har en stark möbelindustri och en stolt tradition av att tillverka tidlösa och högkvalitativa möbler, ofta av naturmaterial. 2016 producerade Sverige möbler för 22,8 miljarder SEK, varav kontorsmöbler stod för nästan en fjärdedel1. Det saknas idag statistik över vad som händer med dessa möbler när de inte längre används, men det står klart att många av dem slängs i förtid när verksamheter flyttar eller när deras behov ändras. Samtidigt syns en tydlig utveckling mot att kunder mer och mer efterfrågar återbrukade eller renoverade möbler som en del i sitt hållbarhetsarbete. Denna utveckling var startpunkten för projektet ”Affärsmodell-innovation för cirkulära möbelflöden”. Affärsmodellinnovation för cirkulära möbelflöden är ett Vinnovafinansierat projekt som under åren 2015-2017 arbetat med att utveckla och testa koncept för cirkulära affärsmodeller för i första hand offentliga möbler. I projektet har tjugo aktörer från hela värdekedjan, från underleverantörer, möbelproducenter, återförsäljare och användare till forskare och branschorgan, samarbetat kring affärsutveckling, kundincitament, produktdesign, logistik, hållbarhets- och certifieringsfrågor. Den här skriften belyser hur nya affärsmodeller för mer cirkulära möbelflöden kan bidra till en mer hållbar utveckling och ger smakprov på slutsatser från projektet. Skriften riktar sig framför allt till producenter och återförsäljare av möbler för offentliga miljöer, men även kunder och inköpare tror vi kan ha stor nytta av skriften. Vi hoppas att den även kan fungera som inspiration för andra industrier och branscher som funderar på en övergång till mer cirkulära affärsekosystem.
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| 5. |
- Bolin, Bryce T., et al.
(författare)
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Characterization of the Nucleus, Morphology, and Activity of Interstellar Comet 2I/Borisov by Optical and Near-infrared GROWTH, Apache Point, IRTF, ZTF, and Keck Observations
- 2020
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 160:1
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Tidskriftsartikel (refereegranskat)abstract
- We present visible and near-infrared (NIR) photometric and spectroscopic observations of interstellar object (ISO) 2I/Borisov taken from 2019 September 10 to 2019 December 20 using the GROWTH, the Apache Point Observatory Astrophysical Research Consortium 3.5 m, and the NASA Infrared Telescope Facility 3.0 m combined with pre- and postdiscovery observations of 2I obtained by the Zwicky Transient Facility from 2019 March 17 to 2019 May 5. Comparison with imaging of distant solar system comets shows an object very similar to mildly active solar system comets with an outgassing rate of similar to 10(27)mol s(-1). The photometry, taken in filters spanning the visible and NIR range, shows a gradual brightening trend of similar to 0.03 mag day(-1)since 2019 September 10 UTC for a reddish object becoming neutral in the NIR. The light curve from recent and prediscovery data reveals a brightness trend suggesting the recent onset of significant H2O sublimation with the comet being active with super volatiles such as CO at heliocentric distances >6 au consistent with its extended morphology. Using the advanced capability to significantly reduce the scattered light from the coma enabled by high-resolution NIR images from Keck adaptive optics taken on 2019 October 4, we estimate a diameter for 2I's nucleus of less than or similar to 1.4 km. We use the size estimates of 1I/'Oumuamua and 2I/Borisov to roughly estimate the slope of the ISO size distribution, resulting in a slope of similar to 3.4 1.2, similar to solar system comets and bodies produced from collisional equilibrium.
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| 6. |
- Bolin, Hans, 1961-
(författare)
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Kulturlandskapets korsvägar : mellersta Norrland under de två sista årtusendena f Kr
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The principal aim of this thesis is to discuss the cultural significance of the material remains in the middle of northern Sweden from the last two millennia BC. Different artefacts and monuments from the provinces of Ångermanland, Jämtland and Medelpad are analysed in order to illuminate the often debated relationship between the coast and the interior. The interpretative discussion focuses both on the spatial distribution and on the contextual significance of the material culture. One of the purposes is to examine how different material remains are distributed in the landscape and how the spatial distribution of similarities and differences can be understood in terms of social relations and culture. The material evidence consists of asbestos-tempered pottery, rhombic shafthole axes, fire-cracked stone mounds, cairns, bronze artefacts, moulds and rock art. The thesis comprises on five separate articles plus an introduction and a conclusion.The analysis of the different source materials reveals that the spatial distribution of the archaeological remains is a complex pattern of variation and overlapping between the coastal and inland areas. It is here suggested that the cultural significance of the source material from the studied area should not be described in terms of a dualism of cultures. The cultural setting can instead be described as a multitudinous structure of kinship relations, marriage exchange, ritual strategies and interactional contexts, in which various groups of mobile hunter-gatherers were involved. The distribution of long-term monuments such as fire-cracked stone mounds, cairns and rock art sites played an important role in binding groups from different parts of the landscape together in a fluctuating system of interaction and kinship relations.The analysis further reveals that there is a dramatic increase in foreign bronze artefacts as well as domestic bronze-casting activities in the studied area during the Late Bronze Age. At the same time one can also notice a change in the decorative pattern on the asbestos-tempered pottery, namely a shift from textile impressed decoration to comb-stamped impressions. The spatial distribution of cairn-monuments, fire-cracked stone mounds and rock art sites are studied in an attempt to illuminate the significance of their location in the landscape. The analysis reveals that different types of watery locations seem to have played a vital role for the rituals and communal activities taking place at these sites. Many of the monuments can also be defined as long-term monuments involved in a repeated rebuilding practice during a very long period of time.
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| 7. |
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| 8. |
- Bolin, Niklas, 1977-, et al.
(författare)
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Patterns of Intra-Party Democracy across the World
- 2017
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Ingår i: Organizing Political Parties. - Oxford : Oxford University Press. - 9780198758631 ; , s. 158-184
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Bokkapitel (refereegranskat)abstract
- Despite the widespread recognition of the relevance of intra-party democracy (IPD), there has been a lamentable scarcity of empirical data suitable for large-N cross-sectional comparative analysis. This has changed with the PPDB project. Against this background this chapter sheds some light on questions about whether and how IPD varies systematically by country and party level criteria. The empirical analysis shows that country-level factors are generally more important than party-level factors. Most importantly, the existence of a party law and levels of trust and affluence are associated with higher levels of IPD. However, we also find that smaller parties, in terms of membership size, are associated with higher levels of IPD. While our results must be interpreted with some caution we believe they constitute a first step towards re-framing the scholarly debate on IPD from what is normatively desirable to a discussion about causes and consequences of variations in IPD.
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| 9. |
- Bolin, Niklas, 1977-, et al.
(författare)
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Reparlamentariseringen av Sverige? Bruket av och betydelsen av riksdagens tillkännagivanden till regeringen
- 2016
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Ingår i: Statsvetenskaplig Tidskrift. - 0039-0747. ; 118:3, s. 307-337
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Tidskriftsartikel (refereegranskat)abstract
- The Reparliamentarization of Sweden? The Use and Relevance of Parliamentary Resolutions to the Government In contrast to the theory of deparliamentarization amongst parliamentary democracies, this article points to the Riksdag’s use of so-called resolutions (tillkännagivanden) to the Government as a sign of growing reparliamentarization. Resolutions in the Swedish context are constitutionally non-binding but politically coercing. From this first study of a hitherto uncharted parliamentary instrument some preliminary conclusions materialise: Resolutions are more complex nowadays than 15–20 years ago requiring more effort from the Government. Parliament’s use of resolutions has, broadly pictured, evolved from unanimous or bipartisan demands on often technical issues to an increasingly politicized tool of reiningin minority governments. In some exceptional cases even issuing a few so-called negative resolutions which essentially seek to infringe the Government’s executive powers. Resolutions may offer a complementary measurement of a government’s parliamentary strength and provide additional insights into the workings of Swedish (and potentially other countries) parliamentarism given additional research.
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| 10. |
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