| 1. |
- Andersson, Niklas, et al.
(författare)
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Models and Implementation of a Dynamic Element Matching DAC
- 2003
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Ingår i: Analog Integrated Circuits and Signal Processing. - Netherlands : Springer. - 0925-1030 .- 1573-1979. ; 34:1, s. 7-16
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Tidskriftsartikel (refereegranskat)abstract
- The dynamic element matching (DEM) techniques for digital-to-analog converters (DACs) has been suggested as a promising method to improve matching between the DAC''s reference levels. However, no work has so far taken the dynamic effects that limit the performance for higher frequenciesinto account. In this paper we present a model describing the dynamic properties of a DEM DAC and compare the simulated results with measurements of a 14-bit current-steering DEM DAC implemented in a 0.35-μm CMOS process. The measured data agrees well with the results predicted by the used model. It is also shown that the DEM technique does not necessarily increase the performance of a DAC when dynamic errors are dominating the achievable performance.
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| 2. |
- Andersson, Ola, et al.
(författare)
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A 14-Bit dual current-steering DAC
- 2003
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Ingår i: Proc. Swedish System-on-Chip Conf., SSoCC'03.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A 14-bit dual current-steering digital-to-analog converter implemented in a 0.25 µm CMOS process is presented in this work. Both implementation issues and measurement results are presented. The measured spurious-free dynamic range is higher than 73 dB for signal frequencies up to 3 MHz, and a measured multi-tone power ratio of approximately 71 dB is reported for an ADSL-like input.
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| 3. |
- Andersson, Ola, et al.
(författare)
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A differential DAC architecture with variable common-mode level
- 2002
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Ingår i: Proc. 2002 IEEE Int. Symp. on Circuits and Systems, ISCAS'02. - 0780374487 ; , s. I-113-I-116
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Konferensbidrag (refereegranskat)abstract
- A differential current-steering digital-to-analog converter (DAC) architecture allowing the common-mode level of the input signal to be varied is presented. Simulation results with models of different DAC nonlinearities indicate that the proposed architecture has a potential of improving the linearity of the converters.
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| 4. |
- Andersson, Ola, et al.
(författare)
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A method of segmenting digital-to-analog converters
- 2003
-
Ingår i: Proc. IEEE Southwest Symposium on Mixed-Signal Design, SSMSD'03. - 0780377788 ; , s. 32-37
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Konferensbidrag (refereegranskat)abstract
- Segmented architectures are often used in digital-to-analog converters (DACs). Here we propose a DAC structure based on recursive decomposition of an N-bit binary DAC into two (N-1) bit DACs and one 1 bit DAC. A DAC model that includes matching errors has been simulated. The simulation results indicate that by using four layers of decomposition it is possible to achieve similar performance as when using seven bits of traditional segmentation.
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| 5. |
- Andersson, Ola, et al.
(författare)
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Combining DACs for improved performance
- 2002
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Ingår i: Proc. 4th IEE Int. Conf. on Advanced A/D and D/A Conversion Techniques and their Applications, ADDA'02.
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Konferensbidrag (refereegranskat)abstract
- This work is an overview of recently proposed methods on combining DACs in order to improve performance. Some further development of these techniques are also presented. The techniques aim at reducing glitches and sensitivity towards limited output impedance in current sources.
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| 6. |
- Andersson, Ola, 1976-, et al.
(författare)
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Spectral shaping of DAC nonlinearity errors through modulation of expected errors
- 2001
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Ingår i: Circuits and Systems, 2001. ISCAS 2001. The 2001 IEEE International Symposium on. - : IEEE. - 0780366859 ; , s. 417-420
-
Konferensbidrag (refereegranskat)abstract
- Traditionally, delta-sigma modulation has been used for shaping of quantization noise. We present a modified version of delta-sigma modulation which also takes into account unwanted nonlinearities by feeding back not only the quantization error, but also the expected physical error. Behavioral-level simulations of a 5th-order structure showing an improvement of up to 4 effective bits are included
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| 7. |
- Ansari, Daniel, et al.
(författare)
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Single-institution experience with solid pseudopapillary neoplasm of the pancreas.
- 2011
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 46:12, s. 1492-1497
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Objective. Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare clinical entity. The objective of this study was to review a single institution's experience with this uncommon tumor, as well as review the literature. Material and Methods. Consecutive patients, who underwent surgery for a pathologically confirmed SPN between 1991 and 2010, were retrospectively reviewed. A PubMed search (January 1980-June 2011) was conducted to identify risk factors for death among SPN patients. Results. The institutional review identified 16 patients with SPN. Thirteen patients were female and three patients were male (median age 34 years). All patients underwent radical resection. Two patients had metastatic disease at the time of operation as evident by the presence of lymph node metastasis and gallbladder metastasis. One developed liver metastasis 4 months postoperatively and subsequently died. The other patient received adjuvant chemotherapy (gemcitabine and capecitabine), and 23 months after the initial operation, no tumor recurrence was detected and the patient is still alive. All other patients remain disease-free. Analysis of 29 fatalities reported in the English literature (including the present case) revealed several atypical features including male gender, old age, tumor size >5 cm, diffuse growth pattern, cellular or nuclear atypia, high mitotic rate, extensive necrosis, extrapancreatic invasion, metastasis and incomplete resection. Conclusions. SPN is not always indolent. Male patients and those with old age, atypical histopathology (large tumors, diffuse growth, cellular/nuclear atypia, mitotic activity, necrosis, invasion/metastasis) and incomplete resection may have a higher risk of recurrence and death, deserving particular attention.
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| 8. |
- Bombarda, F., et al.
(författare)
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Runaway electron beam control
- 2019
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
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Tidskriftsartikel (refereegranskat)
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| 9. |
- Kjellström, Sofia, 1970-, et al.
(författare)
-
Exploring, measuring and enhancing the coproduction of health and well-being at the national, regional and local levels through comparative case studies in Sweden and England : the 'Samskapa' research programme protocol
- 2019
-
Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 9:7
-
Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION:Cocreation, coproduction and codesign are advocated as effective ways of involving citizens in the design, management, provision and evaluation of health and social care services. Although numerous case studies describe the nature and level of coproduction in individual projects, there remain three significant gaps in the evidence base: (1) measures of coproduction processes and their outcomes, (2) mechanisms that enable inclusivity and reciprocity and (3) management systems and styles. By focusing on these issues, we aim to explore, enhance and measure the value of coproduction for improving the health and well-being of citizens.METHODS AND ANALYSIS:Nine ongoing coproduction projects form the core of an interactive research programme ('Samskapa') during a 6-year period (2019-2024). Six of these will take place in Sweden and three will be undertaken in England to enable knowledge exchange and cross-cultural comparison. The programme has a longitudinal case study design using both qualitative and quantitative methods. Cross-case analysis and a sensemaking process will generate relevant lessons both for those participating in the projects and researchers. Based on the findings, we will develop explanatory models and other outputs to increase the sustained value (and values) of future coproduction initiatives in these sectors.ETHICS AND DISSEMINATION:All necessary ethical approvals will be obtained from the regional Ethical Board in Sweden and from relevant authorities in England. All data and personal data will be handled in accordance with General Data Protection Regulations. Given the interactive nature of the research programme, knowledge dissemination to participants and stakeholders in the nine projects will be ongoing throughout the 6 years. External workshops-facilitated in collaboration with participating case studies and citizens-both during and at the end of the programme will provide an additional dissemination mechanism and involve health and social care practitioners, policymakers and third-sector organisations.
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| 10. |
- Markljung, Ellen, et al.
(författare)
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ZBED6, a novel transcription factor derived from a domesticated DNA transposon regulates IGF2 expression and muscle growth
- 2009
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 7:12, s. e1000256-
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Tidskriftsartikel (refereegranskat)abstract
- A single nucleotide substitution in intron 3 of IGF2 in pigs abrogates a binding site for a repressor and leads to a 3-fold up-regulation of IGF2 in skeletal muscle. The mutation has major effects on muscle growth, size of the heart, and fat deposition. Here, we have identified the repressor and find that the protein, named ZBED6, is previously unknown, specific for placental mammals, and derived from an exapted DNA transposon. Silencing of Zbed6 in mouse C2C12 myoblasts affected Igf2 expression, cell proliferation, wound healing, and myotube formation. Chromatin immunoprecipitation (ChIP) sequencing using C2C12 cells identified about 2,500 ZBED6 binding sites in the genome, and the deduced consensus motif gave a perfect match with the established binding site in Igf2. Genes associated with ZBED6 binding sites showed a highly significant enrichment for certain Gene Ontology classifications, including development and transcriptional regulation. The phenotypic effects in mutant pigs and ZBED6-silenced C2C12 myoblasts, the extreme sequence conservation, its nucleolar localization, the broad tissue distribution, and the many target genes with essential biological functions suggest that ZBED6 is an important transcription factor in placental mammals, affecting development, cell proliferation, and growth.
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| 11. |
- Norrman Brandt, Eva
(författare)
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Transformativ förändring och postkonventionellt ledarskap : en retrospektiv fallstudie med fokus på förändringsprocessen och ledarskapet
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduktion. Förändringstakten ökar i samhället och påverkar organisationer och dess medlemmar. Förändringstrycket orsakas av en rad faktorer som teknisk utveckling, förändrad lagstiftning, kunders/intressenters behov och krav och ökande konkurrens på en global arena. Förändring är utmanande och många förändrings-initiativ når inte sina mål. Behovet av transformativ förändring i samhället ökar och forskning har visat på ett samband mellan ledares nivå av vuxenutveckling och framgång i att driva transformativa förändringar.Syfte. Syftet med avhandlingen är dels att studera en tioårig förändringsprocess i en läkemedelsfabrik för att identifiera olika typer av förändring, samt att undersöka om kriterier för transformativ förändring uppfylls. Syftet är även att undersöka ledarskapets påverkan på förändringsprocessen och medarbetares upplevelser av det.Design och metod. Avhandlingen är en retrospektiv single case studie med kvalitativ, induktiv och interaktiv design. Två studier har genomförts grundade på samma empiriska material men med olika analysmetoder. Empirin är inhämtad via 19 semistrukturerade intervjuer samt 4 workshops med ledare i den undersökta organisationen. Mediamaterial, böcker och hemsidor har också använts. I studie I har a/ processdata analyserats kronologiskt och b/ i enlighet med en förändringsmatris som identifierar olika typer av förändring, och c/ i enlighet med kriterierna för transformativ förändring. I studie II har en tematisk innehållsanalys använts med fokus på ledarskap och medarbetares upplevelse av ledarskap och arbetsmetoder. Data har analyserats för att undersöka förekomsten av post-konventionella ledarskapsprinciper.Resultat. Delstudie I redovisar stegen i förändringsprocessen där förändringens karaktär i tre tidsperioder skiftar från finjustering och trimning av verksamheten, via an-passning till en förändringskategori som betecknas nytt vägval. På ett strukturellt plan gjordes en förändring från avdelningar (funktionell organisation) till att organiseras kring läkemedelsproduktflöden där medarbetare med mixade kompetenser arbetade tillsammans. De kulturella antagandena förändrades vid sidan av de rent strukturella förändringarna. Förändringsresan kan betecknas som transformativ, en kulturförflyttning utanför tidigare ramar. Resultatet diskuteras utifrån Pettigrews perspektiv på förändring.Delstudie II visar resultatet av den tematiska studien på förändringar i arbetsmetoder och förhållningssätt, bland annat en förflyttning av mandat och makt ut i organisationens alla delar. Ledarens interventioner och förhållningssätt understödde den organisatoriska och kulturella förflyttningen, och de postkonventionella interventionerna 2011–2014 var sannolikt nödvändiga för att åstadkomma den kraftfulla förflyttning som krävdes. Medarbetare reagerade mestadels positivt på det ökade mandatet och möjligheten att ta ansvar och involveras, men en grupp medarbetare vittnar om osäkerhet och brist på stöd i det nya sättet att leda och arbeta.Konklusion och praktiska implikationer. Transformativ förändring tar tid och kräver involvering av hela organisationen. Ledarskapet har en betydande påverkan även om ett samspel mellan olika faktorer blir betydelsefulla. Denna avhandling ger ett exempel på en transformativ förändring där man lyckats balansera yttre kontextuella krav med inre organisatoriska förflyttningar. Begripliga mål som ändrats i takt med nya ändrade kontextuella förutsättningar har formulerats och känslan för var och när i organisationen nya mål skall driva stycks ha funnits hos ledningen. Avhandlingen stärker tesen att transformativ förändring tar tid, och att postkonventionella ledarskapsprinciper verkar gynnsamt i denna typ av förändring där involvering och samskapande krävs. Avhandlingen bidrar även med en del fakta och exempel som skulle kunna inspirera andra organisationer och ledare till att ta ett steg i riktning mot postkonventionell logik i ledarskapet då detta förefaller skapa förutsättningar för transformation av en organisation och dess kultur.
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| 12. |
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Overview of the JET results
- 2015
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 55:10
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Tidskriftsartikel (refereegranskat)
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| 13. |
|
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| 14. |
- Vesterbacka, Mark, 1966-, et al.
(författare)
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Using different weights in DACs
- 2002
-
Ingår i: Proc. 4th IEE Int. Conf. on Advanced A/D and D/A Conversion Techniques and their Applications, ADDA'02.
-
Konferensbidrag (refereegranskat)abstract
- In this paper we discuss some properties of different codes with their respective sets of weights to be used in digital-to-analog converters (DACs). The thermometer (unratioed) code is widely used instead of a binary code in the most significant bits of a segmented DAC to reduce errors due to weight and timing mismatch. The binary and thermometer codes are two extremes, where the first offers a small digital hardware cost and the latter a large cost. We have investigated some of the properties of these codes and codes with properties in-between; such as linear, polynomial, and segmented codes. Some new ideas and results on using different sets of weights and how to generate them are presented. We present simulation results for some low-order polynomial codes.
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| 15. |
-
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:9
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Tidskriftsartikel (refereegranskat)
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| 16. |
-
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
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Forskningsöversikt (refereegranskat)
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| 17. |
- Aho-Mantila, L., et al.
(författare)
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Assessment of SOLPS5.0 divertor solutions with drifts and currents against L-mode experiments in ASDEX Upgrade and JET
- 2017
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP PUBLISHING LTD. - 0741-3335 .- 1361-6587. ; 59:3
-
Tidskriftsartikel (refereegranskat)abstract
- The divertor solutions obtained with the plasma edge modelling tool SOLPS5.0 are discussed. The code results are benchmarked against carefully analysed L-mode discharges at various density levels with and without impurity seeding in the full-metal tokamaks ASDEX Upgrade and JET. The role of the cross-field drifts and currents in the solutions is analysed in detail, and the improvements achieved by fully activating the drift and current terms in view of matching the experimental signals are addressed. The persisting discrepancies are also discussed.
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| 18. |
- Aiba, N., et al.
(författare)
-
Analysis of ELM stability with extended MHD models in JET, JT-60U and future JT-60SA tokamak plasmas
- 2018
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 60:1
-
Tidskriftsartikel (refereegranskat)abstract
- The stability with respect to a peeling-ballooning mode (PBM) was investigated numerically with extended MHD simulation codes in JET, JT-60U and future JT-60SA plasmas. The MINERVA-DI code was used to analyze the linear stability, including the effects of rotation and ion diamagnetic drift (omega(*i)), in JET-ILW and JT-60SA plasmas, and the JOREK code was used to simulate nonlinear dynamics with rotation, viscosity and resistivity in JT-60U plasmas. It was validated quantitatively that the ELM trigger condition in JET-ILW plasmas can be reasonably explained by taking into account both the rotation and omega(*i) effects in the numerical analysis. When deuterium poloidal rotation is evaluated based on neoclassical theory, an increase in the effective charge of plasma destabilizes the PBM because of an acceleration of rotation and a decrease in omega(*i). The difference in the amount of ELM energy loss in JT-60U plasmas rotating in opposite directions was reproduced qualitatively with JOREK. By comparing the ELM affected areas with linear eigenfunctions, it was confirmed that the difference in the linear stability property, due not to the rotation direction but to the plasma density profile, is thought to be responsible for changing the ELM energy loss just after the ELM crash. A predictive study to determine the pedestal profiles in JT-60SA was performed by updating the EPED1 model to include the rotation and w*i effects in the PBM stability analysis. It was shown that the plasma rotation predicted with the neoclassical toroidal viscosity degrades the pedestal performance by about 10% by destabilizing the PBM, but the pressure pedestal height will be high enough to achieve the target parameters required for the ITER-like shape inductive scenario in JT-60SA.
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| 19. |
- Aiba, N., et al.
(författare)
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Numerical analysis of ELM stability with rotation and ion diamagnetic drift effects in JET
- 2017
-
Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 57:12
-
Tidskriftsartikel (refereegranskat)abstract
- Stability to the type-I edge localized mode (ELM) in JET plasmas was investigated numerically by analyzing the stability to a peeling-ballooning mode with the effects of plasma rotation and ion diamagnetic drift. The numerical analysis was performed by solving the extended Frieman-Rotenberg equation with the MINERVA-DI code. To take into account these effects in the stability analysis self-consistently, the procedure of JET equilibrium reconstruction was updated to include the profiles of ion temperature and toroidal rotation, which are determined based on the measurement data in experiments. With the new procedure and MINERVA-DI, it was identified that the stability analysis including the rotation effect can explain the ELM trigger condition in JET with ITER like wall (JET-ILW), though the stability in JET with carbon wall (JET-C) is hardly affected by rotation. The key difference is that the rotation shear in JET-ILW plasmas analyzed in this study is larger than that in JET-C ones, the shear which enhances the dynamic pressure destabilizing a peeling-ballooning mode. In addition, the increase of the toroidal mode number of the unstable MHD mode determining the ELM trigger condition is also important when the plasma density is high in JET-ILW. Though such modes with high toroidal mode number are strongly stabilized by the ion diamagnetic drift effect, it was found that plasma rotation can sometimes overcome this stabilizing effect and destabilizes the peeling-ballooning modes in JET-ILW.
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| 20. |
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| 21. |
- Andersson, Gustav, et al.
(författare)
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Clinical significance of stromal ER and PR expression in periampullary adenocarcinoma
- 2019
-
Ingår i: Biomarker research. - : Springer Science and Business Media LLC. - 2050-7771. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Tamoxifen treatment has previously been reported to confer life-prolonging effects in patients with advanced pancreatic cancer, and most evidently so in women. None of these trials did however include biomarkers, and the relevance of female hormone signaling in pancreatic or other periampullary adenocarcinoma remains largely unexplored. The aim of this study was to examine the extent and potential clinical significance of estrogen receptor-α (ER) and progesterone receptor (PR) expression in pancreatic and other periampullary cancers. Methods: ER and PR expression was examined using immunohistochemistry on tissue microarrays with primary tumors from a retrospective consecutive cohort of 175 patients with resected periampullary adenocarcinoma, with long-term clinical follow-up. Non-parametric and Chi square tests were applied to examine the associations of stromal ER and PR expression with patient and tumor characteristics. Kaplan-Meier analysis and log rank test were applied to illustrate survival differences in relation to ER and PR expression. Cox regression proportional hazards models were applied to examine the associations between investigative factors and risk of death and recurrence, and to test for interactions between KRAS mutation status and hormone receptor expression in relation to survival. Results: Expression of both ER and PR was more frequent in the tumor-associated stroma than in the epithelium. A significant prognostic interaction, independent of tumor morphology, was found between stromal PR expression and KRAS mutation status in relation to both overall and recurrence-free survival (pinteraction = 0.026 and pinteraction = 0.005), in particular in women (pinteraction = 0.002 and pinteraction = 0.005). Specifically, stromal PR expression was associated with a prolonged survival in patients with KRAS-mutated tumors, whereas the opposite was seen for KRAS wild-type tumors. The prognostic value of ER positivity was limited to the subgroup of women with tumors of pancreatic origin. Conclusions: These results demonstrate that stromal PR rather than ER expression, together with KRAS mutation status, provides long-term prognostic information in patients with periampullary adenocarcinoma. Further study into the mechanistic basis for these observations may unveil important clues to the pathogenesis of these cancers and open up for the discovery of novel treatment options.
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| 22. |
- Andersson, Greger, et al.
(författare)
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Musikens miljöer
- 2006
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Ingår i: Signums svenska kulturhistoria. Frihetstiden. - 9187896788 ; , s. 345-373
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Bokkapitel (populärvet., debatt m.m.)
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| 23. |
- Andersson, Jacob
(författare)
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Aetiologies and Epidemiology of Subdural Haematoma in Infancy
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- According to scientific studies, subdural haematoma (SDH) in combination with retinal haemorrhage and encephalopathy (usually denoted as the triad) during infancy is highly specific for abusive head trauma/shaken baby syndrome, if a fall from over one meter, a traffic accident and certain medical conditions have been excluded. Other studies have challenged this notion since there are witnessed falls from less than one meter which has caused acute SDH, birth-related SDH which have been confirmed to develop into chronic SDH, and external hydrocephalus that can be complicated by a spontaneous SDH or an SDH from minor trauma.These aetiologies have not been taken into consideration in prior studies on abusive head trauma. An independent review on infant abusive shaking from the Swedish Agency for Health Technology Assessment concluded that there was insufficient evidence for determining the specificity of the triad for isolated shaking. The aim of this thesis was to increase the understanding of the aetiologies and the epidemiology of infant SDH. This was accomplished by studying registry data (Paper I and II), descriptive reviews of infants with SDH (paper I, III and IV) and infants subjected to witnessed or spontaneously admitted shaking (paper V).The maximum incidence of fatal AHT in Sweden, 0.6/100 000, was at least 10 times lower than in other Western countries and the risk of unreported fatal AHT was low (Paper I). A majority of the deceased infants had neonatal conditions, several were twins and/or preterm, one had a cerebral vascular condition, and one signs of metabolic disorder (Paper I). Approximately 12 infants every year are diagnosed with SDH beyond the first week of life and the case-fatality rate for all SDH diagnosis categories is 6.2% (Paper II). Males, preterm born and twins have a higher risk to develop SDH in general, and those having an abuse diagnosis had increased odds of being born preterm and small-for-gestational age (Paper II). Chronic SDH has a higher freqency of male and premature infants and a lower mortality rate than acute SDH (Paper III). Infants with chronic CSDH, but not with acute SDH, tend to have findings on neuroimaging and a head circumference that are suggestive of external hydrocephalus complicated by spontaneous SDH or SDH from minor trauma (Paper IV). Intracranial and ocular findings in infants subjected to abusive shaking were rare, seen in 2 out of 36 infants, both with pre-existing intracranial pathology, and of non-specific character (Paper V).In conclusion this thesis provides evidence that non-abusive aetiologies for SDH in infancy may have been overlooked in previous research.
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| 24. |
- Andersson, Jacob, et al.
(författare)
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Differences in head circumference and neuroimaging characteristics : what can they tell about the aetiologies of infant subdural haematoma?
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background Acute (ASDH) and chronic subdural haematoma (CSDH) in infants have been regarded as highly specific for abuse. A recent study showed different risk factors for ASDH and CSDH, indicating that CSDH in many cases was related to external hydrocephalus. Purpose To investigate to what extent external hydrocephalus may explain findings and symptoms interpreted as signs of abusive head trauma. Material and methods Eighty-five infants with ASDH (n=16) and CSDH (n=69) were reviewed with regard to cranio-cortical- (CCW), sino-cortical- (SCW), frontal interhemispheric-(IHW), subarachnoid space width (SSW) and head circumference (HC). In infants with unilateral SDH, the correlation between the contralateral SSW and the ipsilateral CCW and SDH width was calculated. A correlation would imply that the CSDH replaces an already existing extracerebral space.Results Infants with CSDH had significantly higher CCW, SCW, IHW and SSW than infants with ASDH (p < 0.05). The ipsilateral CCW (R = 0.92, p < 0.001) and SDH width (R = 0.81, p < 0.01) were correlated to the contralateral SSW. Increased HC was more prevalent in Infants with CSDH (71%) than in infants with ASDH (14%) (p < 0.01). Forty-two infants, all with CSDH, had at least one of CCW, SCW or IHW ≥ 95th percentile. Twenty infants, all with CSDH, had CCW, SCW and IHW > 5 mm and increased HC. Conclusion A significant proportion of infants with CSDH may have external hydrocephalus as an underlying cause and that parts of the widened subarachnoid space in some infants is replaced by a CSDH.
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| 25. |
- Andersson, Jacob, et al.
(författare)
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Different vulnerability profiles in acute compared to chronic subdural haematoma amongst infants with suspected abusive head trauma
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: In a register study based on ICD 10 coding, there was a similar vulnerability profile (male sex, preterm and small for gestational age) in infants diagnosed with non-traumatic subdural haematoma (SDH) and infants having SDH with abuse diagnosis. However, ICD-10 does not separate between acute (ASDH) and chronic subdural haematoma (CSDH). Purpose: To determine the vulnerability profile in infants having CSDH and ASDH, respectively. Material and methods: A descriptive review of infants with SDH/hygroma examined by the Swedish National Board of Forensic Medicine between 1994 and 2018. Included cases (n=85) were analysed with regard to possible vulnerability factors. Results: Type of subdural fluid could be determined in 85 of 96 cases. Sixteen infants had ASDH and 69 CSDH. Infants with ASDH had the peak incidence during the first month of life, 56% were male, 6% were premature, 13% were twins and 44% died. In infants with CSDH, the peak incidence occurred during the third month of life, 69% were male, 34% were premature, 12% were twins and 4% died. Conclusion: CSDH, but not ASDH, is associated with factors suggesting non-traumatic pathogenesis, for which reason CSDH and ASDH should be analysed separately to extend the knowledge regarding the aetiology of SDH during infancy.
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| 26. |
- Andersson, Jacob, et al.
(författare)
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External Hydrocephalus as a Cause of Infant Subdural Hematoma : Epidemiological and Radiological Investigations of Infants Suspected of Being Abused
- 2022
-
Ingår i: Pediatric Neurology. - : Elsevier. - 0887-8994 .- 1873-5150. ; 126, s. 26-34
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Tidskriftsartikel (refereegranskat)abstract
- Background: Acute subdural hematoma (ASDH) and chronic subdural hematoma (CSDH) in infants have been regarded as highly specific for abuse. Other causes of CSDH have not been investigated in a large population.Purpose: The purpose of this study was to investigate to what extent external hydrocephalus is present in infants with ASDH and CSDH undergoing evaluation for abuse.Material and methods: Eighty-five infants suspected of being abused, with ASDH (n = 16) or CSDH (n = 69), were reviewed regarding age, risk factor profiles, craniocortical width (CCW), sinocortical width (SCW), frontal interhemispheric width (IHW), subarachnoid space width (SSW), and head circumference (HC). In infants with unilateral subdural hematoma (SDH), correlations between contralateral SSW and ipsilateral CCW and SDH width were investigated.Results: Infants with CSDH had significantly lower mortality, were more often premature and male, and had significantly higher CCW, SCW, IHW, and SSW than infants with ASDH (P < 0.05). Ipsilateral CCW (R = 0.92, P < 0.001) and SDH width (R = 0.81, P < 0.01) correlated with contralateral SSW. Increased HC was more prevalent in infants with CSDH (71%) than in infants with ASDH (14%) (P < 0.01). Forty-two infants, all with CSDH, had at least one of CCW, SCW, or IHW ≥95th percentile. Twenty infants, all with CSDH, had CCW, SCW, and IHW >5 mm, in addition to increased HC.Conclusion: A substantial proportion of infants with CSDH who had been suspected of being abused had findings suggesting external hydrocephalus.
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| 27. |
- Andersson, Jacob, et al.
(författare)
-
Gamification of publication metadata : to playfully explore our data
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes a project that aimed to create game concepts and games based on a set of data about research publications. This was done using linked open data, procedural content generation of game content, and iterative game development, with the aim of creating useful games and game concepts.
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| 28. |
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| 29. |
- Andersson, Jacob
(författare)
-
Monitoring the open access policy compliance at Malmö University
- 2013
-
Ingår i: Septentrio Conference Series. - : UiT The Arctic University of Norway. - 2387-3086.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Malmö University implemented an open access policy in 2011. It states that research staff and postgraduate students at Malmö University must deposit a copy of their research publications in the university's open repository Malmö University Electronic Publishing (MUEP), a DSpace installation, unless copyright prevents this. It is our ambition that our researchers will investigate their open access rights for each of their publications, regardless of publication type. In late 2012 we made changes in the submission interface of the repository in order to improve the support given to the researchers regarding copyright issues. With these changes we also made it easier to monitor the compliance with the open access policy. The submission process now asks two new questions. The first of these require the author/submitter to state either that she is aware of her rights to deposit a copy of the publication in an open institutional repository, or ask for assistance. The second question is if the author has the right to make this deposit, or if assistance to interpret the agreement is needed. These mandatory questions have made it easier for our librarian specialized in legal issues to detect where support is needed. Hopefully it also raises awareness of the copyright issues among all authors. Monitoring of the compliance with the open access policy falls under the responsibility of the faculty management. It is done through a web interface, Extramuep, where a spreadsheet detailing a specific year’s publications can be downloaded. One of the columns in the spreadsheet describes, among other things, whether or not that specific publication is in compliance with the open access policy. Our poster presentation will describe - the submission process for a researcher - the work processes of the library’s researcher support staff - how compliance with the policy can be monitored by faculty management - the experiences of the researcher support staff - the result in the form of an increasing number of full text files in the repository The focus in this poster presentation is on how this implementation has changed the day-to-day work of the researcher support staff and the results in repository content quality.
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| 30. |
- Andersson, Jacob, et al.
(författare)
-
National study shows that abusive head trauma mortality in Sweden was at least 10 times lower than in other Western countries.
- 2018
-
Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 107:3, s. 477-483
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: The validity of the diagnostic criteria for abusive head trauma (AHT) and its attributes have been widely debated. This national study investigated the possibility of false positive and false negative cases of fatal AHT in Sweden.METHOD: This was a retrospective evaluation of the records of 733 deceased infants up to the age of 365 days who were examined during 1994-2013 at the six forensic medicine departments. All the records were scrutinised for possible cases of AHT.RESULTS: We included 12 cases, out of which eight had been diagnosed as AHT. Of these 12 infants, eight had a concomitant disease or perinatal illness, five were born prematurely, and three were twins. Figures from other Western countries would suggest 6-7 deaths per 100,000 per year in Sweden but in reality, there was a maximum possible incidence of 0.6 per 100,000 infants per year.CONCLUSION: The risk of unreported fatal AHT in Sweden was low and there may have been cases misdiagnosed as AHT. The at least 10 times lower incidence than has been reported from other Western countries, raises the question if previously reported higher incidences of fatal AHT have been exaggerated.
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| 31. |
- Andersson, Jacob
(författare)
-
Open access är inte nödvändigtvis ickekommersiellt
- 2015
-
Ingår i: Bibliotek i samhälle. - : Bibliotek i Samhälle (BiS). - 0345-1135. ; :3, s. 19-20
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Forskningspublikationer som görs fritt tillgängliga enligt principerna för open access kan i vissa fall utgöra en motvikt till kommersiella, licensierade tidskrifter, men open access förekommer också hos de kommersiella förlagen, som kan göra vinst på författaravgifter och hybridtidskrifter. Med exempel från bland annat Latinamerika diskuteras open access-landskapets komplexitet och möjliga vägar framåt.
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| 32. |
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| 33. |
- Andersson, Lotta, et al.
(författare)
-
Local early warning systems for drought - Could they add value to nationally disseminated seasonal climate forecasts?
- 2020
-
Ingår i: Weather and Climate Extremes. - : ELSEVIER. - 2212-0947. ; 28
-
Tidskriftsartikel (refereegranskat)abstract
- Limited application and use of forecast information restrict smallholder farmers ability to deal with drought in proactive ways. This paper explores the barriers that impede use and uptake of seasonal climate forecasts (SCF) in two pilot communities in Limpopo Province. Current interpretation, translation and mediation of national SCF to the local context is weak. A local early warning system (EWS) was developed that incorporated hydrological modelled information based on national SCF, locally monitored rainfall and soil moisture by a wireless sensor network, and signs from indigenous climate indicators. We assessed to what degree this local EWS could improve interpretation of SCF and increase understanding and uptake by farmers. Local extension staff and champion farmers were found to play important knowledge brokering roles that could be strengthened to increase trust of SCF. The local EWS provided added value to national SCF by involving community members in local monitoring, enacting knowledge interplay with indigenous knowledge and simplifying and tailoring SCF and hydrological information to the local context. It also helped farmers mentally prepare for upcoming conditions even if many do not currently have the adaptive mindsets, economic resources or pre-conditions to positively respond to SCF information.
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| 34. |
- Andersson, Magnus, et al.
(författare)
-
Efficient multi-view ray tracing using edge detection and shader reuse
- 2011
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Ingår i: The Visual Computer. - : Springer Science and Business Media LLC. - 0178-2789 .- 1432-2315. ; 27:6-8, s. 665-676
-
Konferensbidrag (refereegranskat)abstract
- Stereoscopic rendering and 3D stereo displays are quickly becoming mainstream. The natural extension is autostereoscopic multi-view displays, which by the use of parallax barriers or lenticular lenses, can accommodate many simultaneous viewers without the need for active or passive glasses. As these displays, for the foreseeable future, will support only a rather limited number of views, there is a need for high-quality interperspective antialiasing. We present a specialized algorithm for efficient multi-view image generation from a camera line using ray tracing, which builds on previous methods for multi-dimensional adaptive sampling and reconstruction of light elds. We introduce multi-view silhouette edges to detect sharp geometrical discontinuities in the radiance function. These are used to significantly improve the quality of the reconstruction. In addition, we exploit shader coherence by computing analytical visibility between shading points and the camera line, and by sharing shading computations over the camera line.
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| 35. |
- Andersson, Magnus, et al.
(författare)
-
Filtered Stochastic Shadow Mapping Using a Layered Approach
- 2015
-
Ingår i: Computer Graphics Forum. - : Wiley. - 1467-8659 .- 0167-7055. ; 34:8, s. 119-129
-
Tidskriftsartikel (refereegranskat)abstract
- Given a stochastic shadow map rendered with motion blur, our goal is to render an image from the eye with motion-blurred shadows with as little noise as possible. We use a layered approach in the shadow map and reproject samples along the average motion vector, and then perform lookups in this representation. Our results include substantially improved shadow quality compared to previous work and a fast graphics processing unit (GPU) implementation. In addition, we devise a set of scenes that are designed to bring out and show problematic cases for motion-blurred shadows. These scenes have difficult occlusion characteristics, and may be used in future research on this topic.
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| 36. |
- Andersson, Martin N, et al.
(författare)
-
A sex pheromone receptor in the Hessian fly Mayetiola destructor (Diptera, Cecidomyiidae)
- 2016
-
Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 10:SEP2016
-
Tidskriftsartikel (refereegranskat)abstract
- The Hessian fly, Mayetiola destructor Say (Diptera, Cecidomyiidae), is a pest of wheat and belongs to a group of gall-inducing herbivores. This species has a unique life history and several ecological features that differentiate it from other Diptera such as Drosophila melanogaster and blood-feeding mosquitoes. These features include a short, non-feeding adult life stage (1–2 days) and the use of a long-range sex pheromone produced and released by adult females. Sex pheromones are detected by members of the odorant receptor (OR) family within the Lepidoptera, but no receptors for similar long-range sex pheromones have been characterized from the Diptera. Previously, 122 OR genes have been annotated from the Hessian fly genome, with many of them showing sex-biased expression in the antennae. Here we have expressed, in HEK293 cells, five MdesORs that display male-biased expression in antennae, and we have identified MdesOR115 as a Hessian fly sex pheromone receptor. MdesOR115 responds primarily to the sex pheromone component (2S,8E,10E)-8,10-tridecadien-2-yl acetate, and secondarily to the corresponding Z,E-isomer. Certain sensory neuron membrane proteins (i.e., SNMP1) are important for responses of pheromone receptors in flies and moths. The Hessian fly genome is unusual in that it encodes six SNMP1 paralogs, of which five are expressed in antennae. We co-expressed each of the five antennal SNMP1 paralogs together with each of the five candidate sex pheromone receptors from the Hessian fly and found that they do not influence the response of MdesOR115, nor do they confer responsiveness in any of the non-responsive ORs to any of the sex pheromone components identified to date in the Hessian fly. Using Western blots, we detected protein expression of MdesOrco, all MdesSNMPs, and all MdesORs except for MdesOR113, potentially explaining the lack of response from this OR. In conclusion, we report the first functional characterization of an OR from the Cecidomyiidae, extending the role of ORs as long-range sex pheromone detectors from the Lepidoptera into the Diptera.
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| 37. |
- Andersson, Mats, 1957, et al.
(författare)
-
On the Briancon-Skoda theorem on a singular variety
- 2010
-
Ingår i: Annales de l'institut Fourier. - : Cellule MathDoc/CEDRAM. - 0373-0956 .- 1777-5310. ; 60:2, s. 417-432
-
Tidskriftsartikel (refereegranskat)abstract
- Let Z be a germ of a reduced analytic space of pure dimension. We provide an analytic proof of the uniform Briancon-Skoda theorem for the local ring Oz; a result which was previously proved by Huneke by algebraic methods. For ideals with few generators we also get much sharper results.
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| 38. |
- Andersson, Martin, 1981-, et al.
(författare)
-
On the Trade-off Between Runtime and Evaluation Efficiency In Evolutionary Algorithms
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Evolutionary optimization algorithms typically use one or more parameters that control their behavior. These parameters, which are often kept constant, can be tuned to improve the performance of the algorithm on specific problems. However, past studies have indicated that the performance can be further improved by adapting the parameters during runtime. A limitation of these studies is that they only control, at most, a few parameters, thereby missing potentially beneficial interactions between them. Instead of finding a direct control mechanism, the novel approach in this paper is to use different parameter sets in different stages of an optimization. These multiple parameter sets, which remain static within each stage, are tuned through extensive bi-level optimization experiments that approximate the optimal adaptation of the parameters. The algorithmic performance obtained with tuned multiple parameter sets is compared against that obtained with a single parameter set. For the experiments in this paper, the parameters of NSGAII are tuned when applied to the ZDT, DTLZ and WFG test problems. The results show that using multiple parameter sets can significantly increase the performance over a single parameter set.
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| 39. |
- Andersson, Mats, et al.
(författare)
-
Road Friction Estimation
- 2007
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This project is part of the Swedish IVSS program. The aim of IVSS is to stimulate research and development for the road safety of the future. Road conditions with low friction have been identified as a frequent cause of traffic accidents. Therefore, technology to automaticallydetect changes in road conditions and alert the driver or take proper actions with active driver support systems would be a key contribution to increased road safety.The aim of this project was to investigate the possibilities to estimate the tire to road friction.Three different approaches have been developed and evaluated, from concept to early prototypes in test vehicles. In the first method, the estimation of the coefficient of friction is based on the forces and torques that are produced at the front tires at cornering maneuvers.The second method is based on a physical model of the tire behavior and estimates road friction from information on the forces that are produced at straight driving. The third method is based on an optical sensor that classifies the road surface ahead of the vehicle.The three methods have been successfully evaluated in proving ground and public road tests in summer and winter conditions with different tires, and have been compared with reference measurements. The conclusion is that all three methods can be used for tire to road frictionestimation and are recommended for further development and industrialization.
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| 40. |
- Andersson, Niklas, et al.
(författare)
-
A comparison of dynamic element matching in DACs
- 1999
-
Ingår i: Proceedings '99 : Oslo, Norway, 8-9 November 1999. - 8798263722 ; , s. 385-390
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the field of dynamic element matching, DEM, techniques, some "new" important theoretical results have been presented during the last decade. However, no comparison between these different DEM techniques (FRDEM, PRDEM, NSDEM) used in wideband digital-to-analog converters, DACs, has been reported. A brief review of different DEM techniques and a comparison between their properties in terms of complexity, etc., are presented in this paper together with simulation results showing the impact of using different DEM techniques.
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| 41. |
- Andersson, Niklas, 1975-, et al.
(författare)
-
A strategy for implementing dynamic element matching in current-steering DACs
- 2000
-
Ingår i: Mixed-Signal Design, 2000. SSMSD. 2000 Southwest Symposium on. - : IEEE. - 0780359755 ; , s. 51-56
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Interesting comparisons of dynamic element matching (DEM) techniques, have been presented during the last decade. However, not many chip implementations of these DEM techniques have been presented so far. A brief review of different DEM techniques are presented in this paper together with a strategy for implementing the partial randomization DEM, PRDEM, technique in a 3.3 V supply, 14 bit CMOS current-steering wideband digital-to-analog converter (DAC)
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| 42. |
- Andersson, Niklas, 1975-, et al.
(författare)
-
Comparison of Different Dynamic Element Matching Techniques for Wideband CMOS DACs
- 1999
-
Ingår i: Proceedings of the 17th Norchip Conference.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the field of dynamic element matching, DEM, techniques, some ”new” important theoretical results have been presented during the last decade. However, no comparison between these different DEM techniques (FRDEM, PRDEM, NSDEM) used in wideband digital-to-analog converters, DACs, has been reported. A brief review of different DEM techniques and a comparison between their properties in terms of complexity, etc., are presented in this paper together with simulation results showing the impact of using different DEM techniques.
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| 43. |
- Andersson, Niklas, 1975-
(författare)
-
Design of Integrated Building Blocks for the Digital/Analog Interface
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The integrated circuit has, since it was invented in the late 1950's, undergone a tremendous development and is today found in virtually all electric equipment. The small feature size and low production cost have made it possible to implement electronics in everyday objects ranging from computers and mobile phones to smart prize tags. Integrated circuits are typically used for data communication, signal processing and data storage. Data is usually stored in digital format but signal processing can be performed both in the digital and in the analog domain. For best performance, the right partition of signal processing between the analog and digital domain must be used. This is made possible by data converters converting data between the domains. A device converting an analog signal into a digital representation is called an analog-to-digital converter (ADC) and a device converting digital data into an analog representation is called a digital-to-analog converter (DAC). In this work we present research results on these data converters and the results are compiled in three different categories. The first contribution is an error correction technique for DACs called dynamic element matching, the second contribution is a power efficient time-to-digital converter architecture and the third is a design methodology for frequency synthesis using digital oscillators.The accuracy of a data converter, i.e., how accurate data is converted, is often limited by manufacturing errors. One type of error is the so-called matching error and in this work we investigate an error correction technique for DACs called dynamic element matching (DEM). If distortion is limiting the performance of a DAC, the DEM technique increases the accuracy of the DAC by transforming the matching error from being signal dependent, which results in distortion, to become signal independent noise. This noise can then be spectrally shaped or filtered out and hereby increasing the overall resolution of the system. The DEM technique is investigated theoretically and the theory is supported by measurement results from an implemented 14-bit DAC using DEM. From the investigation it is concluded that DEM increases the performance of the DAC when matching errors are dominating but has less effect at conversion speeds when dynamic errors dominate.The next contribution is a new time-to-digital converter (TDC) architecture. A TDC is effectively an ADC converting a time difference into a digital representation. The proposed architecture allows for smaller and more power efficient data conversion than previously reported and the implemented TDC prototype is smaller and more power efficient as compared to previously published TDCs in the same performance segment.The third contribution is a design methodology for frequency synthesis using digital oscillators. Digital oscillators generate a sinusoidal output using recursive algorithms. We show that the performance of digital oscillators, in terms of amplitude and frequency stability, to a large extent depends on the start conditions of the oscillators. Further we show that by selecting the proper start condition an oscillator can be forced to repeat the same output sequence over and over again, hence we have a locked oscillator. If the oscillator is locked there is no drift in amplitude or frequency which are common problems for recursive oscillators not using this approach. To find the optimal start conditions a search algorithm has been developed which has been thoroughly tested in simulations. The digital oscillator output is used for test signal generation for a DAC or used to generate tones with high spectral purity using DACs.
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| 44. |
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| 45. |
- Andersson, Niklas, et al.
(författare)
-
Steady-state cycles in digital oscillators
- 2014
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Digital recursive oscillators locked in steady-state can be used to generate sinusoids with high spectral purity. The locking occurs when the oscillator returns to a previously visited state and repeats its sequence. In this work we propose a new search algorithm and two new search strategies to find all steady-states for a given oscillator configuration. The improvement in spurious-free dynamic range is between 7 and 40 dB compared to previously reported results. The algorithm is also able to find oscillator sequences for more frequencies than previously reported work. A key part of the method is the reduction of the search space made possible by a proposed extension of existing theory on recursive oscillators. Specific properties of digital oscillators in a steady-state are also discussed. It is shown that the initial states can be used to individually control the phase, amplitude, spectral purity, and also cycle length of the oscillator output.
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| 46. |
- Andersson, Ola, 1976-, et al.
(författare)
-
Characterization of a CMOS current-steering DAC using state-space models
- 2000
-
Ingår i: Circuits and Systems, 2000. Proceedings of the 43rd IEEE Midwest Symposium on. - : IEEE. - 0780364759 ; , s. 668-671 vol.2
-
Konferensbidrag (refereegranskat)abstract
- Performance limitations on current-steering digital-to-analog converters (DACs) are due to finite output impedances, nonideal switches, parasitic capacitances, matching, etc. In this work we present a dynamic state-space model of a 14-bit current-steering DAC which includes dynamic nonidealities. Simulation results are presented and compared to measurement results. The model can be used for fast performance estimation of D/A converters
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| 47. |
- Andersson, Ola, 1976-, et al.
(författare)
-
Digital-to-analog converter having error correction
- 2002
-
Patent (populärvet., debatt m.m.)abstract
- The values X(n) input to a current-steering digital-to-analog converter (49) are modified (41) before the actual conversion to compensate for conversion errors of the digital-to-analog converter. The input values are modified according to a model (43) of the digital-to-analog converter in which each output value of the digital-to-analog converter Y(n) is a sum of a desired value directly proportional to the respective input value and an error. The error is a product of the settled output value, i.e. the difference between the desired value and the previous output value Y(n−1) actually provided by the digital-to-analog converter, and a relative step error that is a function only of the respective input signal and is stored in a table. The relative step error can be a function also of the previous output signal and of the previous input signal. This model has a low complexity and is suitable for on-chip implementation.
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| 48. |
- Andersson, Ola, 1976-, et al.
(författare)
-
Modeling of the Influence of Graded Element Matching Errors in CMOS Current-Steering DACs
- 1999
-
Ingår i: Proceedings of the 17th Norchip Conference.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In analog and mixed-mode circuits the matching between circuit elements is crucial.For example, in binary encoded digital-to-analog converters (DACs) the matchingbetween different bit weights can set the limit on the performance. Related to earlier workmodeling the influence of stochastic matching, the influence of graded element matching errorson the performance of current-steering DACs is shown. Presented are calculated results thatcorrelate very well with simulated results. As performance measures we use both static measuresas DNL and INL as well as frequency domain parameters as SNDR and SFDR. This discussioncan also be applied to other DAC structures, for example switched-capacitor.
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| 49. |
- Andersson Sundén, Erik, et al.
(författare)
-
An assessment of nitrogen concentrations from spectroscopic measurements in the JET and ASDEX upgrade divertor
- 2019
-
Ingår i: Nuclear Materials and Energy. - : Elsevier. - 2352-1791. ; 18, s. 147-152
-
Tidskriftsartikel (refereegranskat)abstract
- The impurity concentration in the tokamak divertor plasma is a necessary input for predictive scaling of divertor detachment, however direct measurements from existing tokamaks in different divertor plasma conditions are limited. To address this, we have applied a recently developed spectroscopic N II line ratio technique for measuring the N concentration in the divertor to a range of H-mode and L-mode plasma from the ASDEX Upgrade and JET tokamaks, respectively. The results from both devices show that as the power crossing the separatrix, P-sep, is increased under otherwise similar core conditions (e.g. density), a higher N concentration is required to achieve the same detachment state. For example, the N concentrations at the start of detachment increase from approximate to 2% to approximate to 9% as P-sep, is increased from approximate to 2.5 MW to approximate to 7 MW. These results tentatively agree with scaling law predictions (e.g. Goldston et al.) motivating a further study examining the parameters which affect the N concentration required to reach detachment. Finally, the N concentrations from spectroscopy and the ratio of D and N gas valve fluxes agree within experimental uncertainty only when the vessel surfaces are fully-loaded with N.
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| 50. |
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