| 1. |
- Hemmingsson, Morten, et al.
(författare)
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Estimation of Electro-Mechanical Mode Parameters using Frequency Measurements
- 2001
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Ingår i: Power Engineering Society Winter Meeting, 2001. IEEE. - 0780366727 ; 3
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Konferensbidrag (refereegranskat)abstract
- Oscillation frequency and damping of electro-mechanical modes in a power system have traditionally been determined from events caused by large disturbances such as line switchings or generator tripping. Recent papers have shown the possibility to extract this information during normal operation from measurements of power through, or angle difference across, a transmission line. In this paper these methods are applied to frequency measurements from a 230 V wall-outlet. If accurate frequency and phase estimates can be obtained, this can be used for load control to damp electro-mechanical oscillations. Doing this in the distribution system is easier than in the transmission system. Using frequency for this has the advantage that this signal is available everywhere. It would thus be convenient if the estimation of modes and damping could be done in the distribution system. The results show that it is much harder to detect electro-mechanical mode information from frequency than from angle difference or power. However, it is possible to find the frequency of two electromechanical modes whereas the damping has too large an uncertainty. Fundamental problems when using frequency for mode estimation are further discussed
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| 2. |
- Samuelsson, Olof, et al.
(författare)
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Load Modulation for Damping of Electro-Mechanical Oscillations
- 2001
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Ingår i: [Host publication title missing]. - 0780366727
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Konferensbidrag (refereegranskat)abstract
- Today it is feasible for utilities to control selected customer loads in a nondisturbing fashion. This is comparable to load shedding, but has a wider area of application. This paper focuses on direct load control or modulation for power system damping and is based on a field test of on-off control and modal analysis of differential-algebraic equation models of three test systems. Real power load controlled by bus frequency is found to be robust to changes in network topology. It is shown that on-off modulation is more effective than sinusoidal modulation for damping of large oscillations, but not for small oscillations. It proves difficult to give a general measure of the required amount of controlled load, since modulation of real power loads has an additive rather than multiplicative effect on power flows. Different structures of load control systems are listed. If the system is centralized, it is suggested that the distribution company owns and operates the system and that damping is sold as ancillary service
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| 3. |
- Bylund, Bengt, et al.
(författare)
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Very low birth weight children at 9 years : School performance and behaviour in relation to risk factors
- 2000
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Ingår i: Prenatal and Neonatal Medicine. - 1359-8635 .- 1473-0774. ; 5:2, s. 124-133
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To investigate the school performance and behavior of very low-birth-weight children in comparison with controls, and relate the findings to risk factors. Methods All children with birth weight below 1501 g (VLBW) and normal birth weight (NBW) controls, born in the south-east region of Sweden during a 15-month period in 1987-88, were enrolled in a prospective follow-up study; 81 % (n = 70) and 82% (n = 72), respectively, were re-examined at the age of 9 years regarding growth, neurological status, neurofunctional classification and academic achievement tests (Raven's matrices, mathematics, vocabulary, reading ability). The need for special education at school was assessed and four behavioral problem scores were also assessed (hyperactivity, fine motor skills, gross motor skills, social skills). Children with known handicaps were not re-examined. Results VLBW children were shorter and lighter than controls, and differed from them with regard to neurological functional classification. As a group, they produced poorer results in all academic achievement tests except vocabulary, and also in two out of four behavioral subscales (hyperactivity and fine motor skills). When the comparison was restricted to children with normal Raven scores, almost all the differences disappeared. VLBW children had more reading difficulties but were less often than expected defined as dyslexic compared to NEW children.
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| 4. |
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| 5. |
- Krupic, Ferid, et al.
(författare)
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The Influence of Age, Gender and Religion on Willingness to be an Organ Donor: Experience of Religious Muslims Living in Sweden.
- 2019
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Ingår i: Journal of religion and health. - : Springer Science and Business Media LLC. - 1573-6571 .- 0022-4197. ; 58, s. 847-859
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Tidskriftsartikel (refereegranskat)abstract
- The transplantation of organs is one of the most successful medical advances in recent decades, and transplantation is the treatment of choice for severe organ failure worldwide. Despite this situation and the general acknowledgment of organ donation (OD) as a global priority, the demand for organs outstrips the supply in virtually every country in the world. The study aims to elucidate whether age, gender and religion influence decision-making about organ donation in religious Muslims living in Sweden Data were collected through three group interviews using open-ended questions and qualitative content analysis. Twenty-seven participants, 15 males and 12 females from four countries, participated in the focus group interviews. The analysis of the collected data resulted in three main categories: "Information and knowledge about organ donation," "The priorities when deciding about organ donation" and "The religious aspects of organ donation," including a number of subcategories. Good information about and knowledge of OD, priorities in OD, importance of the fact that religion must be studied and taught daily and religious education were only a few of the factors informants emphasized as predictors of the total and successful donation of organs. Age, gender or religion did not have an impact on organ donation. High levels of education through religious education and good information via various media, as well as a good knowledge of the Swedish language, are predictors of improved OD. In order to overcome religious ideology as a source of misinformation relating to OD and to promote increased OD in the future, specific intervention studies and the improved involvement of religious communities and education in schools and the healthcare system are vital and must be a starting point for improved OD.
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| 6. |
- Samuelsson, Stefan, 1964-, et al.
(författare)
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A longitudinal study of reading skills among very-low-birthweight children : Is there a catch-up?
- 2006
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Ingår i: Journal of Pediatric Psychology. - : Oxford University Press (OUP). - 0146-8693 .- 1465-735X. ; 31:9, s. 967-977
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine the development of reading skills among very-low-birthweight (VLBW) children and to what extent reading difficulties at 9 years of age persist unchanged, are attenuated, or are enhanced at 15 years of age. Methods: Fifty-six VLBW and 52 normal birthweight (NBW) children were assessed on word decoding, word recognition, and reading comprehension at 9 and 15 years of age. Results: VLBW children showed deficits in reading skill at 9 years of age, while most differences obtained at 15 years of age did not reach significance. VLBW children improved their reading comprehension between 9 and 15 years of age more than NBW children, and when controlling for individual differences in IQ, VLBW children improved both their reading comprehension and word-recognition skill. Conclusion: The results suggest that VLBW children display positive changes over time in reading skills. © The Author 2006. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved.
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| 7. |
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| 8. |
- Akke, Magnus, et al.
(författare)
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An object-oriented transformer model in OMOLA
- 1997
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Ingår i: Proceedings of the world congress - International federation of Automatic Control. - 0080429262 ; , s. 259-264
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Konferensbidrag (refereegranskat)
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| 9. |
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| 10. |
- Alterman, Mathias, et al.
(författare)
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P1/P1' modified HIV protease inhibitors as tools in two new sensitive surface plasmon resonance biosensor screening assays
- 2001
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier. - 0928-0987 .- 1879-0720. ; 13:2, s. 203-212
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Tidskriftsartikel (refereegranskat)abstract
- The commonly used HIV-1 protease assays rely on measurements of the effect of inhibitions on the hydrolysis rate of synthetic peptides. Recently an assay based on surface plasmon resonance (SPR) was introduced. We have taken advantage of the fact that the SPR signal is proportional to the mass of the analyte interacting with the immobilised molecule and developed two new improved efficient competition assay methods. Thus, high molecular weight binders were used as amplifiers of the surface plasmon resonance signal. Linkers were attached by a Heck reaction to the para-positions of the P1/P1′ benzyloxy groups of a linear C2-symmetric C-terminal duplicated inhibitor to enable (a) biotin labelling or (b) direct immobilisation of the inhibitor to the biosensor surface matrix. The interaction properties of a series of 17 structurally diverse inhibitors was assessed and compared to previously reported data. The most sensitive assay was obtained by immobilising the enzyme and amplifying the signal with an antibody, giving a detection range between 0.1 nM and 10 μM. Immobilisation of the inhibitor resulted in a stable and durable surface but a narrower detection range (1–100 nM). The two competition assays are anticipated to be very suitable for fast screening of potential HIV inhibitors.
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