| 1. |
- van Eldert, Jeroen, 1987-
(författare)
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Drill Monitoring for Rock Mass Assessment in Tunnelling
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Site investigations for tunnel projects are often unable to determine rock mass conditions accurately for the entire tunnel, as these investigations obtain qualitative data for only limited parts of the tunnel. This is the case at the Stockholm Bypass project in Sweden. At two ramp tunnels, the rock mass was characterised as significantly poorer during the excavation than had been determined previously in the site investigation. In this study, Measurement While Drilling (MWD) technology was employed to characterise the rock mass for grouting purposes using extraction drill monitoring data from the grout holes. In addition, MWD data were extracted from blast holes at the entrance of one access and two ramp tunnels. The MWD data included the penetration rate and feed, percussive, rotation, and water pressure measurements at less than 3cm intervals in the drill holes. The drill rig supplier’s software was able to characterise the rock mass accurately for fracture zones, as shown in a comparison of the fracturing index of grout holes, blast holes, and the mappedrock mass structures. Since the suppliers’ software packages ignored some essential features of drilling, the study developed an improved MWD data normalisation and filtering process. This new process took the effects of different rock drills and drill rod extensions on the MWD data into account. The new normalisation and filtering process showed the capability to describe the rock mass conditions more accuratelythan the current method. A holistic approach was also developed to optimise the rock support process even further. Here, the rock mass was objectively qualified using measured drilling data instead of observations. This process correlated the fracturing index to rock mass quality and rock support requirements. Lastly, a correlation was made between the rock mass quality and the grout requirements per grout umbrella;these requirements were linked to the rock mass conditions determined by the MWD parameters. Based on these relations, a conceptual grout decision-making model was developed. The study found all-in-all tunnel practices could be improved with the implementation of MWD for rock mass characterisation and as part of a rock mass quality control plan. The MWD technology provides additional information on the rock mass and could be incorporated into the observational method for rock mass excavation.
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| 2. |
- He, Zhitao, et al.
(författare)
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Rethinking link-level abstractions for sensor networks
- 2008. - 1
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Konferensbidrag (refereegranskat)abstract
- For designers of the communication stack of sensor nodes there is a constant tension between performance and modularity. To alleviate this tension, researchers have come up with a number of modular architectures. In this work we take a refreshed view of the design of an abstract link level service, an important component in the communication stack. We start with a critical review of one such service, the Sensornet Protocol (SP), and then we implement an SP-flavored link level service featuring a novel combination of ARQ and MAC. Experimental results of transmission delay and energy efficiency highlight a few subtle architectural design trade-offs we have encountered, namely semantics binding, implicit information sharing, and time scope initialization. These aspects have significant impact on software modularity in tiny sensor nodes.
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| 3. |
- Jekell, Andreas, et al.
(författare)
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Treatment of hypertensive left ventricular hypertrophy
- 2018
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Ingår i: Current Pharmaceutical Design. - : Bentham Science Publishers Ltd.. - 1381-6128 .- 1873-4286. ; 24:37, s. 4391-4396
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Forskningsöversikt (refereegranskat)abstract
- Background: The development and risk potential of hypertension-induced left ventricular (LV) hypertrophy has been well described in epidemiological studies. Regression of LV hypertrophy reduces cardiovascular morbidity and mortality. However, the best treatment strategy is still debated, as well as the appropriate blood pressure target in these patients. Objective: We here review the treatment of LV hypertrophy and the potential benefit on clinical outcomes, against a background of the epidemiology and pathophysiology. Results: Both hemodynamic and non-hemodynamic mechanisms contribute to hypertensive LV hypertrophy, which is characterized by an inappropriate myocardial fibrosis. Stringent blood pressure control reduces LV hypertrophy. Blockers of the renin-angiotensin-aldosterone system may have valuable effects on cardiac and electrophysiological remodelling beyond the effects of blood pressure reduction. Thus, they represent a cornerstone in the treatment of hypertensive LV hypertrophy, but most often other antihypertensive drug classes need to be added. Current guidelines indicate a blood pressure target in most patients with hypertensive LV hypertrophy of 120–130/80 mmHg. Conclusions: LV hypertrophy and myocardial fibrosis are important characteristics of hypertensive heart disease and associated with untoward prognosis. Regression of LV hypertrophy reduces cardiovascular morbidity and mortality. New drugs under development may add additional benefit.
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| 4. |
- Asgeirsson, Daniel, et al.
(författare)
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Glomerular sieving of three neutral polysaccharides and bikunin in rat. - Effects of molecular size and conformation.
- 2007
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Ingår i: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 191:3, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Polysaccharides and many other non-protein polymers generally have a more open, flexible and asymmetrical structure compared with globular proteins. For a given molecular weight (MW), the Stokes–Einstein radius (ae) of the following polymers increases in the order: Ficoll < dextran ≤ pullulan < polyethylene oxide (PEO). We have tested the hypothesis that such an increase in 'molecular extension' will increase the molecule's glomerular permeability. Thus, we investigated the glomerular sieving coefficients (θ) of the mentioned polymers and of the negatively charged and extended protein bikunin. Methods: In anaesthetized Wistar rats, glomerular sieving curves were generated for each FITC-labelled polymer from their respective concentration in urine and plasma, determined by size exclusion chromatography. The θ for bikunin was measured using a tissue uptake technique. Results: For a molecule of ae = 55 Å (cf. IgG), θ increased in the order: Ficoll (0.00035 ± 0.000013) < dextran (0.022 ± 0.0029) < pullulan (0.033 ± 0.0024) < PEO (0.12 ± 0.0055). For ae = 36 Å (cf. albumin) the order was: Ficoll (0.076 ± 0.0061) < dextran (0.45 ± 0.037) = pullulan (0.45 ± 0.021) < PEO (0.65 ± 0.0076). θ for bikunin (0.089 ± 0.0045) was 150 times higher than that of albumin, having an equivalent ae and net negative charge. Conclusion: From these results it is concluded that for flexible and asymmetric macromolecules, their degree of glomerular hyperpermeability is proportional to their degree of 'molecular extension'. Thus, compared with globular proteins, the polysaccharides investigated, including Ficoll, were found to be hyperpermeable across the glomerular filter in vivo.
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| 5. |
- van Vlokhoven, Has
(författare)
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The effect of open access on research quality
- 2019
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Ingår i: Journal of Informetrics. - : Elsevier BV. - 1751-1577 .- 1875-5879. ; 13:2, s. 751-756
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Tidskriftsartikel (refereegranskat)abstract
- The number of articles being published open access has been increasing and some research funders are starting to mandate their researchers to publish solely in open access-only journals. Reasons to promote open access include that it might lower costs and increase the diffusion of knowledge. One unintended consequence of moving to a system in which all journals are APC-based open access might be that high-quality journals become more lenient and start accepting lower quality articles compared to what they would do under subscription-based access. Using a game-theoretical analysis I show that this is indeed the case as long as readers value research quality to some extent. Moreover, if in addition to open access authors are no longer evaluated based on metrics of the journals in which they publish then quality standards of journals will deteriorate further. Hence, journals will no longer be providing the service of selecting the highest quality articles to its readers. This might in fact lower the diffusion of knowledge, as readers will have to spend more time on judging the quality, being at odds with one of the main reasons for promoting open access.
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| 6. |
- Buiras, Pablo, 1986, et al.
(författare)
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HLIO: Mixing Static and Dynamic Typing for Information-Flow Control in Haskell
- 2015
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Ingår i: ACM SIGPLAN Notices. - New York, NY, USA : ACM. - 1523-2867. ; 50:9, s. 289-301
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Tidskriftsartikel (refereegranskat)abstract
- Information-Flow Control (IFC) is a well-established approach for allowing untrusted code to manipulate sensitive data without disclosing it. IFC is typically enforced via type systems and static analyses or via dynamic execution monitors. The LIO Haskell library, originating in operating systems research, implements a purely dynamic monitor of the sensitivity level of a computation, particularly suitable when data sensitivity levels are only known at runtime. In this paper, we show how to give programmers the flexibility of deferring IFC checks to runtime (as in LIO), while also providing static guarantees---and the absence of runtime checks---for parts of their programs that can be statically verified (unlike LIO). We present the design and implementation of our approach, HLIO (Hybrid LIO), as an embedding in Haskell that uses a novel technique for deferring IFC checks based on singleton types and constraint polymorphism. We formalize HLIO, prove non-interference, and show how interesting IFC examples can be programmed. Although our motivation is IFC, our technique for deferring constraints goes well beyond and offers a methodology for programmer-controlled hybrid type checking in Haskell.
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| 7. |
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| 8. |
- Nelhans, Gustaf
(författare)
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Qualitative Scientometrics?
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- When scientometricians are asked about the relationship between citations and quality, they often argue along the lines that citations could be seen as indicators of use and that that this implies usefulness and impact on other research, which in turn is an argument for using them as indicators of quality. This paper questions the implicit linearity of such a ‘one-dimensional model’ of representing quality by quantity from a number of standpoints. First, the use of citations as well as any indicator that is used is performative in the sense that those getting measured by them, i.e. researchers or university administrators, will adapt their behavior to perform well on the scales that are used, either for recognition or for monetary reward. Second, equating citation counts with quality might imply a notion that they scale together such that low citation rates equals low quality and that a high rate implies high quality. Third, and most important, drawing from theories in STS it could be argued that scientometric indicators and measures of scientific achievement are co-produced, in the sense that development of performance based or results based indicators and what is to be regarded as high quality will be found to increasingly coincide with each other as a consequence of the performative idiom mentioned above. It is suggested that more work on the qualitative aspects of scientometric data and is called for.
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| 9. |
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| 10. |
- Scheidegger, Samuel, 1985, et al.
(författare)
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Mono-Camera 3D Multi-Object Tracking Using Deep Learning Detections and PMBM Filtering
- 2018
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Ingår i: IEEE Intelligent Vehicles Symposium, Proceedings. ; 2018-June, s. 433-440
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Konferensbidrag (refereegranskat)abstract
- Monocular cameras are one of the most commonly used sensors in the automotive industry for autonomous vehicles. One major drawback using a monocular camera is that it only makes observations in the two dimensional image plane and can not directly measure the distance to objects. In this paper, we aim at filling this gap by developing a multi-object tracking algorithm that takes an image as input and produces trajectories of detected objects in a world coordinate system. We solve this by using a deep neural network trained to detect and estimate the distance to objects from a single input image. The detections from a sequence of images are fed in to a state-of-the art Poisson multi-Bernoulli mixture tracking filter. The combination of the learned detector and the PMBM filter results in an algorithm that achieves 3D tracking using only mono-camera images as input. The performance of the algorithm is evaluated both in 3D world coordinates, and 2D image coordinates, using the publicly available KITTI object tracking dataset. The algorithm shows the ability to accurately track objects, correctly handle data associations, even when there is a big overlap of the objects in the image, and is one of the top performing algorithms on the KITTI object tracking benchmark. Furthermore, the algorithm is efficient, running on average close to 20 frames per second.
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