| 1. |
- Nyberg, Lars, et al.
(författare)
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Memory aging and brain maintenance
- 2012
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Ingår i: Trends in cognitive sciences. - : Elsevier BV. - 1364-6613 .- 1879-307X. ; 16:5, s. 292-305
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Tidskriftsartikel (refereegranskat)abstract
- Episodic memory and working memory decline with advancing age. Nevertheless, large-scale population-based studies document well-preserved memory functioning in some older individuals. The influential 'reserve' notion holds that individual differences in brain characteristics or in the manner people process tasks allow some individuals to cope better than others with brain pathology and hence show preserved memory performance. Here, we discuss a complementary concept, that of brain maintenance (or relative lack of brain pathology), and argue that it constitutes the primary determinant of successful memory aging. We discuss evidence for brain maintenance at different levels: cellular, neurochemical, gray- and white-matter integrity, and systems-level activation patterns. Various genetic and lifestyle factors support brain maintenance in aging and interventions may be designed to promote maintenance of brain structure and function in late life.
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| 2. |
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| 3. |
- Jafari, Hedyeh, et al.
(författare)
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A novel data driven model of ageing postural control
- 2019
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Konferensbidrag (refereegranskat)abstract
- BackgroundPostural control is a complex system. Based on sensorimotor integration, the central nervous system (CNS) maintains balance by sending suitable motor commands to the muscles. Physiological decline due to ageing, affects balance performance through failing postural control – and in turn affects falls self-efficacy and activity participation. Understanding how the CNS adapts to these changes and predicts the appropriate motor commands to stabilize the body, has been a challenge for postural control research the latest years.AimsTo understand and model the performance of the central nervous system as the controller of the human body.MethodsModelling was based on postural control data from 45 older adults (70 years and older). Ankle, knee and hip joint kinematics were measured during quiet stance using a motion capture system. Principal component analysis was used in order to reduce the measured multidimensional kinematics from a set of correlated discrete time series to a set of principal components. The outcome was utilized to predict the motor commands. The adaptive behaviour of the CNS was modelled by recurrent neural network including the efference copy for rapid predictions. The data from joint kinematics and electromyography (EMG) signals of the lower limb muscles were measured and separated into training and test data sets.ResultsThe model can predict postural motor commands with very high accuracy regardless of a large physiological variability or balancing strategies. This model has three characteristics: a) presents an adaptive scheme to individual variability, 2) showcases the existence of an efference copy, and 3) is human experimental data driven.ConclusionThe model can adapt to physical body characteristics and individual differences in balancing behaviour, while successfully predict motor commands. It should therefore be utilised in the continued pursuit of a better understanding of ageing postural control.
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| 4. |
- Norén, Viveca, 1972-, et al.
(författare)
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Flood riskassessment – Practices in flood prone Swedish municipalities
- 2016
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Ingår i: International Journal of Disaster Risk Reduction. - Uppsala Univ, Dept Earth Sci, Villavagen, SE-75236 Uppsala, Sweden. [Noren, Viveca; Bishop, Kevin] Uppsala Univ, Dept Earth Sci, Villavagen 16, SE-75236 Uppsala, Sweden. [Noren, Viveca; Nyberg, Lars; Bishop, Kevin] Uppsala Univ, Ctr Nat Disaster Sci, Villavagen 16, SE-75236 Uppsala, Sweden. [Hedelin, Beatrice; Nyberg, Lars] Karlstad Univ, Dept Environm & Life Sci, Ctr Climate & Safety, SE-65188 Karlstad, Sweden. [Bishop, Kevin] Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, POB 7050, SE-75007 Uppsala, Sweden. : Elsevier. - 2212-4209. ; 18, s. 206-217
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Tidskriftsartikel (refereegranskat)abstract
- Risk assessments are important to ensure efficient and effective flood risk management. Methods and strategies for flood risk assessment are described in the literature, but less is known about how assessments are actually performed. We have studied local flood risk assessments in Sweden by interviewing flood risk managers in municipalities and analyzing documentation of flood risk assessment efforts.There is a large variation between municipalities in how flood risk assessment has been done. The efforts made in association with the EU Floods Directive together with a Government Commission about a flood in Lake Mälaren are the most advanced assessments. Only a few of the municipalities have done comparable assessments. Generally, however, there is a lack of experience and theoretical knowledge about concepts and methods of flood risk assessment in the municipalities. In the assessments studied, the flood it self had been rather well defined in hazard maps. The consequences of a flood had been studied in the larger projects but only by half of the municipalities. It is mainly direct, tangible consequences that have been included. It is mainly the exposure of assets that has been investigated while little attention has been paid to vulnerability. To improve flood risk assessment in Sweden there is a need for knowledge and resources in the municipalities. Prioritization and motivation are needed to actually perform the assessments. National guidelines for may be helpful to guide municipalities in this work and to have more uniform risk assessment.
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| 5. |
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| 6. |
- Cronhjort, Mikael, 1965-, et al.
(författare)
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Civilingenjör och lärare – ett bidrag till hållbar ingenjörsutbildning
- 2017
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Konferensbidrag (refereegranskat)abstract
- Vi har studerat hur kombinationsutbildningen Civilingenjör och lärare på KTH bidrar till att avhjälpa lärarbristen och därigenom bidrar till en hållbar ingenjörsutbildning. Studien bygger på data från enkäter och intervjuer med programmets alumner. Enkätmaterialet visar att cirka 30% av alumnerna arbetar i gymnasieskolan, 60% i näringslivet och 10% med övrigt, exempelvis i organisationer eller på universitet. Alumnerna anser sig vara gynnade på arbetsmarknaden. De har ett starkt självförtroende och en mycket positiv bild av den egna kompetensen.
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| 7. |
- Nielsen, Lars, 1955-, et al.
(författare)
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Issues in Diagnosis, Supervision, and Safety
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Issues concerning diagnosis, supervision and saftey are found in many technologically advanced products. There is now a trend to extend the functionality of diagnosis and supervision systems to handle more advanced situations. This report collects some of the initiatives taking place in research and some of the developments taking place in the industry.
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| 8. |
- Nyberg, Mattias, et al.
(författare)
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A Universal Chow-Willsky Scheme and Detectability Criteria
- 2000
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Ingår i: IEEE Transactions on Automatic Control. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9286 .- 1558-2523. ; 45:1, s. 152-156
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Tidskriftsartikel (refereegranskat)abstract
- An important issue in diagnosis research is design methods for residual generation. One method is the Chow-Willsky scheme. Here, the Chow-Willsky scheme is extended as it becomes universal in the sense that, for both discrete and continuous linear systems, it is shown to be able to generate all possible parity functions. This result means it can also be used to design all possible residual generators. It is shown that previous extensions to the Chow-Willsky scheme are not universal, which is the case when dynamics controllable from faults exist, but not from the inputs or disturbances. Also included here are two conditions on the process for fault detectability and strong fault detectability.
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| 9. |
- Nyberg, Mattias, et al.
(författare)
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Design of a Complete FDI System based on a Performance Index With Application to an Automotive Engine
- 1997
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Konferensbidrag (refereegranskat)abstract
- Assuming residual generators are already available, there are still several choices to be made when a complete FDI system is to be designed. This is a time-consuming engineering work so for this purpose, a systematic procedure is proposed. The procedure is phrased as an optimization problem. The goal is to minimize a new probability based performance index, which is derived from measurements on the real process. To increase the robustness of the FDI system, a don’t care option is introduced in the residual structure. The procedure is successfully applied to the problem of FDI design for the air intake system of an SI-engine.
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| 10. |
- Nyberg, Mattias, et al.
(författare)
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Model Based Diagnosis for the Air Intake System of the SI-Engine
- 1998
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Ingår i: SAE technical paper series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191. ; 106, s. 9-20
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Tidskriftsartikel (refereegranskat)abstract
- Because of legislative regulations like OBDII, on-board diagnosis has gained much interest lately. A model based approach is suggested for the diagnosis of the air intake system of an SI-engine. Important research issues are modeling concepts, residual generation and evaluation, overall performance, and limiting factors. The diagnosis system is based on a non-linear semi-physical model and uses a combination of different residual generation methods. It is capable of detecting and isolating faults in the throttle actuator, throttle sensor, air mass flow sensor and manifold pressure sensor. The scheme is experimentally validated on a real production engine.
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