| 1. |
- Gustafsson, Fredrik, et al.
(författare)
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Particle Filters for Positioning, Navigation and Tracking
- 2001
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A framework for positioning, navigation and tracking problems using particle filters (sequential Monte Carlo methods) is developed. It consists of a class of motion models and a general non-linear measurement equation in position. A general algorithm is presented, which is parsimonious with the particle dimension. It is based on marginalization, enabling a Kalman filter to estimate all position derivatives, and the particle filter becomes low-dimensional. This is of utmost importance for high-performance real-time applications. Automotive and airborne applications illustrate numerically the advantage over classical Kalman filter based algorithms. Here the use of non-linear models and non-Gaussian noise is the main explanation for the improvement in accuracy. More specifically, we describe how the technique of map matching is used to match an aircraft's elevation profile to a digital elevation map, and a car's horizontal driven path to a street map. In both cases, real-time implementations are available, and tests have shown that the accuracy in both cases is comparable to satellite navigation (as GPS), but with higher integrity. Based on simulations, we also argue how the particle filter can be used for positioning based on cellular phone measurements, for integrated navigation in aircraft, and for target tracking in aircraft and cars. Finally, the particle filter enables a promising solution to the combined task of navigation and tracking, with possible application to airborne hunting and collision avoidance systems in cars.
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| 2. |
- Nilsson, B, et al.
(författare)
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Effects of preoperative parathyroid localisation studies on the cost of operations for persistent hyperparathyroidism.
- 2001
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Ingår i: The European journal of surgery = Acta chirurgica. - : Oxford University Press (OUP). - 1102-4151. ; 167:8, s. 587-91
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Tidskriftsartikel (refereegranskat)abstract
- To find out whether preoperative parathyroid localisation studies are cost-effective in patients with persistent hyperparathyroidism (HPT).Retrospective study.University hospital, Sweden.29 consecutive patients with persistent HPT who were reoperated on with or without localisation studies. 15 other patients had initial operations for HPT without localisation studies.Initial or repeat operation for HPT, localisation studies with 99mTc sestamibi scintigraphy, and catheterisation of large cervical and mediastinal veins with measurements of serum concentrations of parathyroid hormone.Operative time. Cost of operations, frozen section biopsy and localisation studies.The mean durations of reoperation with localisation studies and for the initial operation without them, were 124 and 135 minutes, respectively, while it was 269 minutes for reoperation without studies. For patients who had localisation studies the mean total cost of the investigations, operating time, and frozen section biopsy was 28% less than for patients who were reoperated on without such studies.Preoperative localisation studies before repeat operations for HPT were cost-effective. Even if it has not been shown in this series, the reduction in operating time and the extent of dissection by localisation studies has the potential to decrease morbidity.
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| 3. |
- Nordlund, Per-Johan, et al.
(författare)
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A Framework for Particle Filtering for Positioning, Navigation and Tracking
- 2001
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Ingår i: Proceedings of the 11th IEEE Signal Processing Workshop on Statistical Signal Processing. - : IEEE. - 0780370112 ; , s. 34-37
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Konferensbidrag (refereegranskat)abstract
- A framework for positioning, navigation and tracking problems using particle filters (recursive Monte Carlo methods) is developed. Automotive and airborne applications, approached in this framework, have proven a numerical advantage over classical Kalman filter based algorithms. Here the use of non-linear measurement models and non-Gaussian measurement noise is the main explanation for the improvement in accuracy, and models for relevant sensors are surveyed.
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| 4. |
- Svensson, Johan, 1964, et al.
(författare)
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Effects of growth hormone and its secretagogues on bone.
- 2001
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Ingår i: Endocrine. - 0969-711X. ; 14:1, s. 63-6
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Tidskriftsartikel (refereegranskat)abstract
- The growth hormone (GH)/insulin-like growth factor-1 axis is not only of importance for linear body growth during childhood, but it is also one of the major determinants of adult bone mass. Studies show that GH treatment increases bone mass in rodents as well as in adult GH-deficient humans, but the effect of GH treatment on bone mass in healthy humans has so far not been impressive. Recently, a new class of GH secretagogues (GHSs) has been developed. In humans, GHS treatment affects biochemical markers of bone turnover and increases growth velocity in selected short children with or without GH deficiency. In rodents, GHS treatment increase bone mineral content, but it has not yet been shown that GHS treatment can affect bone mass in adult humans.
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