| 1. |
- Petrachenko, Bill, et al.
(författare)
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Design Aspects of the VLBI2010 System
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report summarizes the progress made in developing the next generation VLBI, dubberd the VLBI2010 system. The VLBI2010 Committee of the International Service for Geodesy and Astrometry (IVS) worked on the design aspects of the new system.…
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| 2. |
- Wild, W., et al.
(författare)
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Millimetron—a large Russian-European submillimeter space observatory
- 2009
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:1, s. 221-244
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Tidskriftsartikel (refereegranskat)abstract
- Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution.
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| 3. |
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Proceedings of the 7th International Space Syntax Symposium
- 2009
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Proceedings (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- [Foreword to the printed proceedings]The Space Syntax symposia are by now recognised as an established tradition in international architectural research, a tradition that combines high scientific rigour with high relevance for architectural practice. It will be the primary aim of the organisers of the Stockholm symposium to carry on this tradition.Still, each symposium has its own flavour due to continuous changes in the global society, but also due to the local context of each symposium. We believe that contemporary Stockholm presents a situation in architecture and urban design of great international relevance. Stockholm is often described as a successful city in these fields, but it is a success to a high degree relying on a top-down approach to architectural and urban development. From a local horizon it is becoming obvious how Stockholm needs to learn from the kind of bottom-up urban processes often prevalent in cities less often described as successful.To a large degree it is the study of such self-organising and emergent processes in buildings and cities that is at the heart of Space Syntax research. Since this implies an exploration of the field of the possible in architectural and urban design, one here also finds the reason for the high relevance of Space Syntax for architectural practice. We hope that this tension between top-down and bottom-up approaches in architecture and urban design will be a lasting memory of the Stockholm symposium.
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| 4. |
- Demetriades, G. D., et al.
(författare)
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Small-signal analysis of the half-bridge soft-swithing uni-directional converter employing extended state-space averaging
- 2008
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Ingår i: PESC Record - IEEE Annual Power Electronics Specialists Conference. - 9781424416684 ; , s. 385-391, s. 385-391
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Konferensbidrag (refereegranskat)abstract
- In the present paper the small-signal model of the half-bridge soft-switched Single Active Bridge is derived. In order to derive the small-signal model of the specific topology an extended state-space averaging method based on half-cycle symmetry has been used and is briefly described in the paper. The results obtained have been verified experimentally.
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| 5. |
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| 6. |
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| 7. |
- Chilo, José, et al.
(författare)
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Discrimination of nuclear explosions sites by seismic signals using intrinsic mode functions and multi-modal data space
- 2008
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Ingår i: 2008 IEEE International Geoscience and Remote Sensing Symposium - Proceedings; Boston, MA; 6 July 2008 through 11 July 2008. ; , s. II895-II898, s. 895-898
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Konferensbidrag (refereegranskat)abstract
- Signal processing and feature extraction are investigated using the Empirical Mode Decomposition (EMD). It is believed that this approach is well suited for non-linear and non-stationary data. With EMD any complicated set of data can be decomposed into a finite, and usually small number, of functions called Intrinsic Mode Functions (IMFs). A new discriminating system is presented here that is capable of discriminating between different seismic signals from nuclear testing sites based on the IMFs and the multi-modal data space. The advantage of this space is that multiple metrics of similarity are converted into one single Euclidean space. This space is capable of extracting similarities among several signals through a combination of multiple metrics. This is a new way of associating data. After illustrating the technique with an investigation of an audio data example (piano), we examine the characteristics of seismic signals from nuclear testing (explosions). The results presented in this paper indicate that a relatively simple discriminating system can successfully cluster and classify seismic events.
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| 8. |
- Carlsson, Ella, et al.
(författare)
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Analysis of the mass composition of the escaping plasma at Mars
- 2006
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Ingår i: 2006 European Geosciences Union General Assembly (EGU 2006), Austria Center Vienna, Vienna (Austria), 2-7 Apr 2006. - : European Geosciences Union (EGU).
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Results from Mars Express, Mars Exploration Rovers and Mars Global Surveyor indicate that Mars harbored large amounts of liquid water on the surface in the past. In order for the water-associated geomorphologic features to form, the pressure in the atmosphere must have been at least a hundred times higher to produce the necessary greenhouse effect required to hold liquid water stable. The present atmospheric pressure is only 6-9 mbar and moreover, the spectral imaging of Mars suggests that the amount of carbonates stored in the surface is too low in order to explain the denser atmosphere in the past. This controversy led us to investigate the escaping plasma by analyzing the data from the IMA sensor (Ion Mass Analyzer) of the ASPERA-3 instrument suite onboard Mars Express. The IMA sensor measures the differential flow of ion components in the energy range of 0.01-30 keV/q.Since the instrument design was optimized for studies of plasma dynamics, the mass resolution is not adequate enough to directly resolve CO+2 from O+2 , which is the main molecular ion composing the Mars ionosphere according to theoretical models. Therefore, a special multi-species fitting technique, using calibration and in-flight data, was developed to resolve the CO+2 peak from the neighboring and much more intense O+2 peak. This technique was applied to the observations covering the period from April 4, 2004 to October 2, 2005. The events of heavy ion escape were identified inside the induced magnetosphere boundary and the Martian eclipse. We report the results of statistical studies of these ion-beam events which permitted to determine CO+2 / O+ and the O+2 / O+ ratio of the escaping plasma at Mars.
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| 9. |
- Carlsson, Ella, et al.
(författare)
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Cold Mars
- 2006
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 10. |
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