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| 2. |
- Ratajczak-Tretel, B, et al.
(författare)
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Prediction of underlying atrial fibrillation in patients with a cryptogenic stroke : results from the NOR-FIB Study
- 2023
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Ingår i: Journal of Neurology. - 1432-1459. ; 270:8, s. 4049-4059
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Atrial fibrillation (AF) detection and treatment are key elements to reduce recurrence risk in cryptogenic stroke (CS) with underlying arrhythmia. The purpose of the present study was to assess the predictors of AF in CS and the utility of existing AF-predicting scores in The Nordic Atrial Fibrillation and Stroke (NOR-FIB) Study.METHOD: The NOR-FIB study was an international prospective observational multicenter study designed to detect and quantify AF in CS and cryptogenic transient ischaemic attack (TIA) patients monitored by the insertable cardiac monitor (ICM), and to identify AF-predicting biomarkers. The utility of the following AF-predicting scores was tested: AS5F, Brown ESUS-AF, CHA 2DS 2-VASc, CHASE-LESS, HATCH, HAVOC, STAF and SURF. RESULTS: In univariate analyses increasing age, hypertension, left ventricle hypertrophy, dyslipidaemia, antiarrhythmic drugs usage, valvular heart disease, and neuroimaging findings of stroke due to intracranial vessel occlusions and previous ischemic lesions were associated with a higher likelihood of detected AF. In multivariate analysis, age was the only independent predictor of AF. All the AF-predicting scores showed significantly higher score levels for AF than non-AF patients. The STAF and the SURF scores provided the highest sensitivity and negative predictive values, while the AS5F and SURF reached an area under the receiver operating curve (AUC) > 0.7.CONCLUSION: Clinical risk scores may guide a personalized evaluation approach in CS patients. Increasing awareness of the usage of available AF-predicting scores may optimize the arrhythmia detection pathway in stroke units.
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| 3. |
- Shi, K., et al.
(författare)
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Extracting Separation Surfaces of Path Line Oriented Topology in Periodic 2D Time-Dependent Vector Fields
- 2007
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Ingår i: Journal of WSCG. - 1213-6964. ; 15:1, s. 75-82
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approach to extracting the separation surfaces from periodic 2D time-dependent vector fields based on a recently introduced path line oriented topology. This topology is based on critical path lines which repeat the same spatial cycle per time period. Around those path lines there are areas of similar asymptotic flow behavior basins which are captured by a 2D Poincare map as a discrete dynamical system. Due to pseudo discontinuities in this map and the discrete integration scheme, separatrices between the basins can not be obtained as integral curves. Instead we choose a point-wise approach to segment the Poincare map and apply computer vision algorithms to extract the 2D separation curves. Starting from those curves we integrate separation surfaces which partition the periodic 2D time-dependent vector field into areas of similar path line behavior. We apply our approach to a number of data sets to to demonstrate its utility.
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| 4. |
- Shi, K., et al.
(författare)
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Path Line Attributes - an Information Visualization Approach to Analyzing the Dynamic Behavior of 3D Time-Dependent Flow Fields
- 2009
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Ingår i: Topology-Based Methods in Visualization II. - : Springer. ; , s. 75-88
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- We describe an approach to visually analyzing the dynamic behavior of 3D time-dependent flow fields by considering the behavior of the path lines. At selected positions in the 4D space-time domain, we compute a number of local and global properties of path lines describing relevant features of them. The resulting multivariate data set is analyzed by applying state-of-the-art information visualization approaches in the sense of a set of linked views (scatter plots, parallel coordinates, etc.) with interactive brushing and focus+context visualization. The selected path lines with certain properties are integrated and visualized as colored 3D curves. This approach allows an interactive exploration of intricate 4D flow structures. We apply our method to a number of flow data sets and describe how path line attributes are used for describing characteristic features of these flows.
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| 5. |
- Shi, K., et al.
(författare)
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Path Line Oriented Topology for Periodic 2D Time-Dependent Vector Fields
- 2006
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Ingår i: Proc. Eurographics / IEEE VGTC Symposium on Visualization (EuroVis ’06). ; , s. 139-146
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Konferensbidrag (refereegranskat)abstract
- This paper presents an approach to extracting a path line oriented topological segmentation for periodic 2D time-dependent vector fields. Topological methods aiming in capturing the asymptotic behavior of path lines rarely exist because path lines are usually only defined over a fixed time-interval, making statements about their asymptotic behavior impossible. For the data class of periodic vector fields, this restriction does not apply any more. Our approach detects critical path lines as well as basins from which the path lines converge to the critical ones. We demonstrate our approach on a number of test data sets.
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| 6. |
- Olbrich, S., et al.
(författare)
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Lösungsansätze zur Visualisierung im High Performance Computing und Networking Kontext
- 2002
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Ingår i: Zukunft der Netze - Die Verletzbarkeit meistern.. ; , s. 269-279
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Konferensbidrag (refereegranskat)abstract
- In diesem Paper stellen wir ein Echtzeit-Szenario zur Überwachung und Steuerung von entfernt laufenden Großsimulationen vor, das auf einer Extraktion von Geometrien aus den Simulationsdaten, deren Übertragung über Hochgeschwindigkeitsnetze zu einem Client und der daraufhin erfolgenden Simulationssteuerung beruht. Wir stellen die Probleme eines solchen Szenarios dar und präsentieren Lösungen für diese Probleme. Basis dieses Papers ist das BMBF-geförderte DFN-Projekt "`Anwendungen der Teleimmersion in Weitverkehrsnetzen"' - einem Gigabit-Testbed mit Partnern in Berlin (ZIB) und Hannover (RRZN/RVS, Institut für Meteorologie und Klimatologie).
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| 7. |
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| 8. |
- Shi, K., et al.
(författare)
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Finite-Time Transport Structures of Flow Fields
- 2008
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Ingår i: Proc. IEEE Pacific Visualization 2008. - : IEEE Computer Society. - 9781424419661 ; , s. 63-70
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Konferensbidrag (refereegranskat)abstract
- Modern experimental and computational fluid mechanics are increasingly concerned with the structure nature of fluid motion. Recent research has highlighted the analysis of one transport structure which is called Lagrangian coherent structure. However, the quantity nature of the flow transport is still unclear. In this paper, we focus on the transport characteristics of physical quantities and propose an approach to visualize the finite-time transport structure of quantity advection. This is similar to an integral convolution over a scalar field along path-lines of a flow field. Applied to a well chosen set of physical quantity fields this yields structures giving insights into the dynamical processes of the underlying flow. We demonstrate our approach on a number of test data sets.
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| 9. |
- Shi, K., et al.
(författare)
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Visualizing Transport Structures of Time-Dependent Flow Fields
- 2008
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Ingår i: IEEE Computer Graphics and Applications. - 0272-1716 .- 1558-1756. ; 28:5, s. 24-36
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Tidskriftsartikel (refereegranskat)abstract
- This article focuses on the transport characteristics of physical properties in fluids - in particular, visualizing the finite-time transport structure of property advection. Applied to a well-chosen set of property fields, the proposed approach yields structures giving insights into the underlying flow’s dynamic processes.
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| 10. |
- Theisel, H., et al.
(författare)
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Extraction of Parallel Vector Surfaces in 3D Time-Dependent Fields and Application to Vortex Core Line Tracking
- 2005
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Ingår i: Proc. IEEE Visualization 2005. - 0780394623 ; , s. 631-638
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Konferensbidrag (refereegranskat)abstract
- We introduce an approach to tracking vortex core lines in time-dependent 3D flow fields which are defined by the parallel vectors approach. They build surface structures in the 4D space-time domain. To extract them, we introduce two 4D vector fields which act as feature flow fields, i.e. their integration gives the vortex core structures. As part of this approach, we extract and classify local bifurcations of vortex core lines in space-time. Based on a 4D stream surface integration, we provide an algorithm to extract the complete vortex core structure. We apply our technique to a number of test data sets.
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