| 61. |
- 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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| 62. |
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| 63. |
- Jonsson, Magnus, 1969-, et al.
(författare)
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Time-deterministic WDM star network for massively parallel computing in radar systems
- 1996
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Ingår i: Proceedings of the Third International Conference on Massively Parallel Processing Using Optical Interconnections. - Los Alamitos, California : IEEE Computer Society Press. - 0818675918 ; , s. 85-93
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Konferensbidrag (refereegranskat)abstract
- In massively parallel computer systems for embedded real-time applications there are normally very high bandwidth demands on the interconnection network. Other important properties are time-deterministic latency and services to guarantee that deadlines are met. In this paper we analyze how these properties vary with the design parameters for a passive optical star network, specifically when used in a massively parallel radar signal processing system. The aggregated bandwidth and computational power of the radar system are approximately 45 Gb/s and 100 GOPS, respectively. The analysis is focused on the medium access control protocol, called TD-TWDMA, for the time and wavelength multiplexed network. It is concluded that the proposed network is very well suited to this kind of signal-processing applications. We also present a new distributed slot-allocation algorithm with real-time properties.
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| 64. |
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| 65. |
- Jonsson, Oskar, et al.
(författare)
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Experiences of a User-Centred Research Approach involving Old People in Early Phases of Design; Reflections from Furniture Manufacturers
- 2013
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Ingår i: [Host publication title missing]. ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- The paper concerns the furniture industry’s increased interest in opportunities and challenges to respond to demographic shifts and to meet future senior markets. A central issue discussed is how a user-centred approach in a collaborative design research project benefited the industrial partners. The paper focuses on the perspectives of the participating furniture manufacturers. The most involved representatives from each of the seven participating companies in the project were recruited as respondents. Semi-structured interviews were carried out. The results indicate that a user-centred design research approach with an early focus on old people contributed with knowledge on a general level that benefited the industrial partners. All respondents stated that they were strengthened in their presumptions about old people as furniture users and consumers. The majority stated that their understanding of end users improved. Based on lessons learnt three recommendations for future work in co-operative design research projects are: (1) to establish a mutual understanding of the different roles and perspectives of the design researchers and the industrial partners, (2) involve as many stakeholders as possible and (3) use prototypes and iterative design processes.
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| 66. |
- Jonsson, Robert, 1989, et al.
(författare)
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A comparison between quantum and classical noise radar sources
- 2020
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Ingår i: IEEE National Radar Conference - Proceedings. - 1097-5659.
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Konferensbidrag (refereegranskat)abstract
- We compare the performance of a quantum radar based on two-mode squeezed states with a classical radar system based on correlated thermal noise. With a constraint of equal number of photons N-S transmitted to probe the environment, we find that the quantum setup exhibits an advantage with respect to its classical counterpart of root 2 in the cross-mode correlations. Amplification of the signal and the idler is considered at different stages of the protocol, showing that no quantum advantage is achievable when a large-enough gain is applied, even when quantum-limited amplifiers are available. We also characterize the minimal type-II error probability decay, given a constraint on the type-I error probability, and find that the optimal decay rate of the type-II error probability in the quantum setup is ln(1 + 1/N-S) larger than the optimal classical setup, in the N-S << 1 regime. In addition, we consider the Receiver Operating Characteristic (ROC) curves for the scenario when the idler and the received signal are measured separately, showing that no quantum advantage is present in this case. Our work characterizes the trade-off between quantum correlations and noise in quantum radar systems.
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| 67. |
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| 68. |
- Jonsson, Sigurdur, et al.
(författare)
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Monte Carlo studies of protein aggregation
- 2012
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Ingår i: Physics Procedia. - : Elsevier BV. - 1875-3892. ; 34, s. 49-54
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Konferensbidrag (refereegranskat)abstract
- The disease-linked amyloid beta (A beta) and alpha-synuclein (alpha S) proteins are both fibril-forming and natively unfolded in free monomeric form. Here, we discuss two recent studies, where we used extensive implicit solvent all-atom Monte Carlo (MC) simulations to elucidate the conformational ensembles sampled by these proteins. For alpha S, we somewhat unexpectedly observed two distinct phases, separated by a clear free-energy barrier. The presence of the barrier makes alpha S, with 140 residues, a challenge to simulate. By using a two-step simulation procedure based on flat-histogram techniques, it was possible to alleviate this problem. The barrier may in part explain why fibril formation is much slower for alpha S than it is for A beta.
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| 69. |
- Jonsson, Sverrir, et al.
(författare)
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THE MÚLAJÖKULL DRUMLIN FIELD - SEDIMENTOLOGY AND GEOMORPHOLOGY
- 2011
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Ingår i: Geological Society of America abstracts with programs Minneapolis 2011.
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Konferensbidrag (refereegranskat)abstract
- The drumlin field in front of Múlajökull, a surge-style, outlet glacier from Hofsjökull in Iceland, is the only known active drumlin field (Johnson et al., 2010). The aim of this study is to further explore the formation of drumlins in a modern glacial environment. We use data from geological sections, DEMs, aerial imagery and field mapping. Here we present preliminary results from section logging and geomorphological mapping in the summer of 2011. Geomorphological mapping of the drumlin field both with DEMs and ground proofing has revealed over 100 drumlins and a number of drumlinized ridges. The drumlins furthest from the present ice margin appear broader and have lower relief than those closer to the ice. We suggest that this reflects an evolution of the drumlin form during recurrent surging. The drumlins farther away from the ice have experienced fewer surges than those that have just been uncovered due to retreat of the ice margin. During successive surges, the drumlins become narrower and develop higher relief. In one section close to the present ice margin, we identified at least 9 till beds in the crest of a drumlin, each likely the product of a surge, representing approximately 1/3 of the drumlin relief. The top till bed parallels the drumlin form and truncates the older tills. The older units also dip parallel to the drumlin form, but at a slightly lower angle. We believe that this represents an earlier, broader shape of the drumlin prior to the more recent surges, implying an evolution of form similar to that seen in the evolution in form in the drumlin field. The Múlajökull drumlins have thus grown during surging by erosion on the proximal end and sides of the drumlin followed by accretion of till sheets concentrically on the resulting form.
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| 70. |
- Jonsson, Vanessa, et al.
(författare)
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A Scalable Formulation for Engineering Combination Therapies for Evolutionary Dynamics of Disease
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- It has been shown that optimal controller synthesis for positive systems can be formulated as a linear program. Leveraging these results, we propose a scalable iterative algorithm for the systematic design of sparse, small gain feedback strategies that stabilize the evolutionary dynamics of a generic disease model. We achieve the desired feedback structure by augmenting the optimization problems with l1 and l2 regularization terms, and illustrate our method on an example inspired by an experimental study aimed at finding appropriate HIV neutralizing antibody therapy combinations in the presence of escape mutants.
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