| 531. |
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| 532. |
- Jonsson, Magnus, 1969-, et al.
(författare)
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Analysing AFDX Networks Using End-to-end Response Time Analysis
- 2015
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Ingår i: Journal of Interconnection Networks. - Singapore : World Scientific. - 0219-2659 .- 1793-6713. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a novel real-time analysis framework for AFDX (Avionics Full Duplex Switched Ethernet) networks. The framework, based on end-to-end response time analysis, calculates not only delay bounds, but also the maximum jitter for each VL (Virtual Link) at each hop, which is necessary according to the AFDX standard. Moreover, the framework supports multicasting, i.e., VLs with several paths, and VLs with arbitrary delay bounds, i.e., shorter, longer, or equal to their periods. An analysis method to calculate the worst-case buffer population is included in the framework, as it is important to guarantee that no buffer-overflow occurs. With a performance surpassing that of Network Calculus and comparable with Trajectory Approach, our framework presents a good choice due to its many features and its foundation in well-accepted analysis methods.
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| 533. |
- Jonsson, Malin, et al.
(författare)
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Animation of Water Droplet Flow on Structured Surfaces
- 2002
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Ingår i: Sigrad 2002. - 9173734640 ; , s. 17-22
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Konferensbidrag (refereegranskat)abstract
- Several methods for rendering and modeling water have been made and a few of them address the natural phenomenon of water droplets flow. As far as we know, none of those methods have used bump maps in order to simulate the flow of a droplet on structured surfaces. The normals of the bump map, that describes the geometry of the micro structured surface, are used in the flow computation of the droplets. As a result, the water droplets will meander down on the surface as if it has a micro structure. Existing models were not suitable for this purpose. Therefore, a new model is proposed in this paper. The droplet will also leave a trail, which is produced by changing the background texture on the surface. This method will not present a physically correct simulation of water droplets flow on a structured surface. However, it will produce a physically plausible real-time animation.
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| 534. |
- Jonsson, Michael, 1955, et al.
(författare)
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Apathy is a prominent neuropsychiatric feature of radiological white-matter changes in patients with dementia.
- 2010
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Ingår i: International journal of geriatric psychiatry. - : Wiley. - 1099-1166 .- 0885-6230. ; 25:6, s. 588-95
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Cerebral white-matter changes (WMCs) are frequently found in dementia and have been proposed to be related to vascular factors and a certain symptomatological profile. However, few studies have included both vascular factors and a broad spectrum of cognitive, neurological and psychiatric symptoms, easily detectable by the physician in the everyday clinical work. The objective was to study the relationships between WMCs on MRI/CT and neuropsychiatric symptoms and vascular factors in patients with cognitive impairment. METHODS: One hundred and seventy-six patients with Alzheimer's disease, vascular dementia, mixed dementia, and mild cognitive impairment were included. All patients underwent a standardized examination including medical history, clinical examinations, laboratory tests and brain imaging (CT or MRI). The identification and severity degree of WMCs was assessed blindly to clinical findings, using a semi-quantitative scale. For statistical analyses, patients were grouped based on absence or presence of WMCs. Significant variables in bivariate analyses were included as predictors in stepwise multiple logistic regression analyses. RESULTS: Bivariate analyses showed significant associations between WMCs and age, gender, blood pressure, hypertension, ischaemic heart disease and TIA/RIND. Furthermore, there were significant associations between WMCs and apathy, mental slowness, disinhibition, gait disturbance and focal neurologic symptoms. The multivariate logistic model revealed apathy, mental slowness and age as the most consistent predicting factors for WMCs, together with MRI as a radiological method for the detection of WMCs. CONCLUSIONS: The findings indicate that WMCs in patients with dementia are associated with a dysexecutive-related behavioural symptom profile, vascular factors related to small and large vessel diseases and age. Copyright (c) 2009 John Wiley & Sons, Ltd.
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| 535. |
- Jonsson, Michael, 1955, et al.
(författare)
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Cerebrospinal fluid biomarkers of white matter lesions - cross-sectional results from the LADIS study.
- 2010
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Ingår i: European journal of neurology. - : Wiley. - 1468-1331 .- 1351-5101. ; 17:3, s. 377-382
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: White matter lesions (WMLs) caused by small vessel disease are common in elderly people and contribute to cognitive impairment. There are no established biochemical markers for WMLs. We aimed to study the relation between degree of WMLs rated on magnetic resonance imaging of the brain and cerebrospinal fluid (CSF) levels of structural biomarkers associated with Alzheimer's disease (AD) and subcortical vascular dementia. Methods: Fifty-three non-demented elderly individuals with WMLs were subjected to lumbar puncture. Degree of WMLs was rated using the Fazekas scale. Volumetric assessment of WMLs was performed. CSF samples were analyzed for the 40 and 42 amino acid fragments of amyloid beta, alpha- and beta-cleaved soluble amyloid precursor protein, total tau (T-tau), hyperphosphorylated tau (P-tau(181)), neurofilament light protein (NFL), sulfatide and CSF/Serum-albumin ratio. Results: Fifteen subjects had mild, 23 had moderate and 15 had severe degree of WMLs. CSF-NFL levels differed between the groups (P < 0.001) and correlated with the volume of WMLs (r = 0.477, P < 0.001). CSF sulfatide concentration displayed similar changes but less strongly. T-tau, P-tau(181) and the different amyloid markers as well as CSF/S-albumin ratio did not differ significantly between the groups. Conclusions: The association of increased CSF-NFL levels with increasing severity of WMLs in non-demented subjects suggests that NFL is a marker for axonal damage in response to small vessel disease in the brain. This manifestation may be distinct from or earlier than the neurodegenerative process seen in AD, as reflected by the lack of association between WMLs and AD biomarkers.
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| 536. |
- Jonsson, Mattias, et al.
(författare)
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Cost-effectiveness of silvicultural measures to increase substrate availability for red-listed wood-living organisms in Norway spruce forests
- 2006
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Ingår i: Biological Conservation. - : Elsevier. - 0006-3207 .- 1873-2917. ; 127:4, s. 443-467
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Tidskriftsartikel (refereegranskat)abstract
- It is important that measures to maintain biodiversity are taken in a way that is cost-effective for the landowner. We analyzed the cost-effectiveness of silvicultural measures that aim at increasing the substrate availability for red-listed (species that are threatened, near threatened or where species probably are threatened but data is deficient) saproxylic (wood-inhabiting) organisms. We modelled stands of Norway spruce (Picea abies) in three regions of Sweden by using computer simulations and a database with substrate requirements of saproxylic beetles and cryptogams on the Swedish Red-List. Conclusions concerning cost-effectiveness of silvicultural measures depend on the extinction thresholds of the species they are intended to conserve; measures that generate only small amounts of coarse woody debris (CWD) may provide too little substrate to be useful for species with high extinction thresholds. In northern Sweden, forestland is relatively inexpensive, so a cost-effective strategy to increase the amount of spruce CWD was to set aside more forests as reserves. In central and southern Sweden, more emphasis should instead be given to increasing the amount of CWD in the managed forest. The regulations by the Forest Stewardship Council (FSC) could be made more cost-effective by prescribing creation of more high stumps and retention of larger amounts of naturally dying trees. Large-sized CWD, CWD from slow-growing trees, and CWD in late decay stages are substrate types that were particularly rare in managed forest in relation to unmanaged forests. Manual soil scarification and retention of living trees are measures that can increase the proportion of these underrepresented CWD types.
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| 537. |
- Jonsson, Micael, et al.
(författare)
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Divergent responses of beta-diversity among organism groups to a strong environmental gradient
- 2016
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Ingår i: Ecosphere. - : Wiley. - 2150-8925 .- 2150-8925. ; 7:10
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Tidskriftsartikel (refereegranskat)abstract
- A limited understanding of how variation in the species composition among communities (i.e., beta-diversity) changes along natural environmental gradients, and the mechanisms responsible, inhibits our ability to understand large-scale biodiversity change resulting from either natural or anthropogenic drivers. Therefore, our aim was to test key drivers of beta-diversity patterns along a strong, natural environmental gradient for seven widely different organisms groups, that is, root-associated fungi, litter fungi, soil nematodes, vascular plants, epiphytic lichens, beetles, and spiders. Using previously published community-level data from boreal-forested islands, we calculated alpha-diversity and beta-diversity for each of the seven organism groups. Out of several available environmental variables, we identified four variables, that is, ecosystem age, total C storage, net primary productivity (NPP), and N-to-P ratio, as potential predictors of variation in beta-diversity. We found that ecosystem age was the variable with the highest overall importance. We then used two different methods to quantify the relative importance of stochastic and deterministic processes underlying patterns in beta-diversity along the ecosystem age gradient, and our detailed knowledge based on prior data collection in the study system to mechanistically explain among-group differences in these patterns. We found divergent responses in beta-diversity along the age gradient for the seven different organism groups, due to among-group differences in the relative importance of deterministic vs. stochastic community assembly, and attributed these results to reliance on resources from different energy channels that are not always related to NPP. Our results highlight the necessity to consider the importance of taxon-specific resources, and not only NPP, to obtain an understanding of beta-diversity patterns among organism groups and ecosystems, as well as large-scale patterns in biodiversity. They therefore also suggest that management and protection of beta-biodiversity in the landscape requires explicit consideration of a wide range of habitats.
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| 538. |
- Jonsson, Magnus, 1969-, et al.
(författare)
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Fiber-ribbon pipeline ring network for high-performance distributed computing systems
- 1997
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Ingår i: Proceedings of the Third International Symposium on Parallel Architectures, Algorithms, and Networks, 1997. (I-SPAN '97). - : IEEE. ; , s. 138-143
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a high-bandwidth ring network built up with fiber-ribbon point-to-point links. The network has support for both packet switched and circuit switched traffic. Very high throughputs can be achieved in the network due to pipelining, i.e., several packets can be traveling through the network simultaneously but in different segments of the ring. The network can be built today using fiber-optic off-the-shelf components. The increasingly good price/performance ratio for fiber-ribbon links indicates a great success potential for the proposed kind of networks. We also present a massively parallel radar signal processing system with exceptionally high demands on the communication network. An aggregated throughput of tens of Gb/s is needed in this application, and this is achieved with the proposed network.
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| 539. |
- Jonsson, Marie, 1979-, et al.
(författare)
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Force Controlled Assembly of a Compliant Rib
- 2011
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Ingår i: Proceedings of SEA AeroTech Congress and Exhibition 2011, 18th-21st October, Toulouse, France. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
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Konferensbidrag (refereegranskat)abstract
- Automation in aerospace industry is often in the form of dedicated solutions and focused on processes like drilling, riveting etc. The common industrial robot has due to limitations in positional accuracy and stiffness often been unsuitable for aerospace manufacturing. One major cost driver in aircraft manufacturing is manual assembly and the bespoke tooling needed. Assembly tasks frequently involve setting relations between parts rather than a global need for accuracy. This makes assembly a suitable process for the use of force control. With force control a robot equipped with needed software and hardware, searches for desired force rather than for a position. To test the usefulness of force control for aircraft assembly an experimental case aligning a compliant rib to multiple surfaces was designed and executed. The system used consisted of a standard ABB robot and an open controller and the assembly sequence was made up of several steps in order to achieve final position. The result shows that the process is robust and repetitive and has the potential to reduce the need for bespoke jigs and fixtures.
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| 540. |
- Jonsson, Marie, 1979-, et al.
(författare)
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Force Feedback for Assembly of Aircraft Structures
- 2010
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Ingår i: Proceedings of the SAE 2010 Aerospace Manufacturing and Automated Fastening Conference & Exhibition. - SAE International : SAE International.
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Konferensbidrag (refereegranskat)abstract
- Variability in composite manufacture and the limitations in positional accuracy of common industrial robots have hampered automation of assembly tasks within aircraft manufacturing. One way to handle geometry variations and robot compliancy is to use force control. Force control technology utilizes a sensor mounted on the robot to feedback force data to the controller system so instead of being position driven, i.e. programmed to achieve a certain position with the tool, the robot can be programmed to achieve a certain force. This paper presents an experimental case where a compliant rib is aligned to multiple surfaces using force feedback and an industrial robot system from ABB. Two types of ribs where used, one full size carbon fiber rib, and one smaller metal replica for evaluation purposes. The alignment sequence consisted of several iterative steps and a search procedure was implemented within the robot control system. The technology has the potential to lessen the need for dedicated tooling, reduce the need for traditional workspace calibration and can be used in several other applications, such as pin and socket type assemblies found in pylons or landing gear or “part to part” assemblies such as leading edge ribs to spar.
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