| 131. |
- Persson, Anders, et al.
(författare)
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Reverse conversion architectures for signed-digit residue number systems
- 2006
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Ingår i: Proceedings - IEEE International Symposium on Circuits and Systems 2006. - New York : IEEE Press. - 0780393899 - 9780780393905 ; , s. 2701-2704
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Konferensbidrag (refereegranskat)abstract
- This paper presents circuits for conversion from radix-2 signed-digit residue numbers to binary form. Four reverse converters for combined RNS/SD number systems based on different moduli sets are presented. Implementations are compared with respect to timing, area and area-delay products. Finite impulse response (FIR) filters are used as reference designs in order to evaluate the performance of RNS/SD processing in a typical DSP block using the suggested moduli sets.
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| 132. |
- Persson, Anders, 1953-
(författare)
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Rymden i bilden
- 2002
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Ingår i: Odontologisk riksstämma, Göteborg 2002,2002. ; , s. 42-42
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Konferensbidrag (refereegranskat)
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| 133. |
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| 134. |
- Persson, Anders, et al.
(författare)
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Samspel och spänningar mellan profession, styrning och kvalitet i lärarutbildningen
- 2010
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Ingår i: [Host publication title missing]. ; , s. 1-24
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Konferensbidrag (refereegranskat)abstract
- I föreliggande paper undersöker vi vad det innebär att lära till lärare i samspelet och spänningarna mellan profession, styrning och kvalitet. Mot bakgrund av det kvalitetsarbete vi i hög grad varit involverade i inom lärarutbildningen vid Högskolan i Halmstad frågar vi: Hur kan ett kvalitetsarbete inom en lärarutbildning utformas i spänningsfältet mellan extern styrning och professionellt handlingsutrymme? Först diskuteras lärares yrkesutövning ur ett professionsperspektiv. Därefter aktualiserar vi kort lärarutbildningens ställning i det svenska högre utbildningsväsendet med utgångspunkt från ett styrningsperspektiv. Slutligen redogör vi detaljerat för det kvalitetsarbete vi varit med om att utveckla inom lärarutbildningen mot bakgrund av en diskussion om hur kvalitet inom högre utbildning kan definieras. Slutsatsen blir att kvalitetsarbetet kan och bör avväga förhållandet mellan styrning och professionellt handlingsutrymme. Lärarutbildningen bör inom ramen för kvalitetsarbetet göra motstånd mot alltför detaljerad styrning till förmån för lärarens professionella handlingsutrymme.
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| 135. |
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| 136. |
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| 137. |
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| 138. |
- Persson, Anders, 1978-, et al.
(författare)
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Stage-models for public e-services - investigating conceptual foundations
- 2005
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Ingår i: the 2nd Scandinavian Workshop on e-Government,2005.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Information technology has since the turn of the millennia been one of the core issues in the reform of public administration in government agencies. Aiding this development has in some countries and in the research community been discussed through the development of stage models describing the evolution of services in stages. This is the case in Sweden where the Swedish agency for administrative development has been using a model to describe, evaluate and promote the emerging services. This paper pivots on the discussion about the conceptual foundation for models such as the Swedish model and other models. The discussion is conceptually founded in information systems actability theory and IS usage situations. This paper addresses the issue of stage models and the concept of stages itself. The models discussed lack in the categorization of the described stages; borders between stages are undistinguishable and unclear. A refined model that addresses the discovered issues is presented in the paper.
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| 139. |
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| 140. |
- Persson, Anders, et al.
(författare)
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State of the art Intracavity Optogalvanic Spectroscopy at Uppsala University
- 2013
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Konferensbidrag (refereegranskat)abstract
- About five years ago, the first reports of a novel and ultrasensitive method for ro-vibrational spectroscopy of isotope ratios were published [1-3]. The method was called intracavity optogalvanic spectroscopy (ICOGS), and claimed a sensitivity and limit-of-detection (LOD) for detection of radiocarbon in the 10-15range. Applied to measuring the isotopic composition of carbon samples, ICOGS utilizes the narrow linewidth ro-vibrational absorption lines of CO2 in the long-wavelength IR spectrum, typically between 10 - 13 µm [4]. These absorption lines are strongly dependent on the isotopic composition of the CO2 molecule, where a 14CO2 line typically is separated by several hundred linewidths form the nearest 12CO2 and 13CO2 lines. In order to facilitate unambiguous detection of radiocarbon, which is typically 1010-1012 times less abundant than the isotopes 12C and 13C, the sample is moved inside the laser cavity of a 14CO2 laser. This intracavity approach has been claimed to increase the sensitivity of the detection by almost seven orders of magnitude as compared to traditional ‘extracavity’ optogalvanic spectroscopy [3]. However, despite the methodical and thorough efforts of at least five research groups worldwide, the exceptional claims regarding the sensitivity and LOD of ICOGS have not been possible to confirm. As the first research group to properly repeat the original experiments, we recently reported [5] serious deficiencies in the reproducibility of the original results [1-3]. We found that ICOGS in its original embodiment suffers from considerable problems with the stability and reproducibility of the optogalvanic signal, and that these uncertainties, together with mix-ups and mistakes, likely are the explanation for the extraordinary sensitivity in the original reports. An example of the irreproducibility of the original results can be seen in Fig. 1 (a) where the shape of the P20 line of 14C16O2 with different 14C concentrations is shown. As can be seen, the previously reported Voight profile-like line shape, indicating resonant absorption [3], was not found for 14C concentrations in the 10-13 ‒10-11 range, but only for samples with much higher 14C concentration. The problems with stability and reproducibility can be traced back to instabilities in the plasma source, in which the sample is partially ionized in order to extract the optogalvanic signal. The plasma sources currently used in ICOGS are based on 30 years old technology and suffer from problems with both electromagnetic interference and reproducibility in terms of the discharge conditions (pressure, temperature, etc.). In order to overcome these problems, we aim to deploy a completely novel kind of plasma source, based on a stripline split-ring resonator (SSRR), for ICOGS, Fig. 1 (b). We have recently published a report on the applicability of such a plasma source for ordinary optogalvanic spectroscopy [6], and now intend to optimize it for ICOGS. Based on its intrinsic properties, an SSRR could not only improve the stability of the signal, but also reduce the non-resonant background in the spectrum, and facilitate analysis of smaller samples. The latter is due to its extremely small size, with an analyzed volume in the order of 10 µl, Fig. 1 (c). In this report, we summarize our criticism towards the original publications on ICOGS, and report on the latest development regarding our efforts in the deployment of the SSRR plasma source.
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