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Mapping Procedure (mapping + procedure)
Selected AbstractsGeneralization of cluster treatment of characteristic roots for robust stability of multiple time-delayed systemsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 14 2008Rifat Sipahi Abstract A new perspective is presented for studying the stability robustness of nth order systems with p rationally independent delays. It deploys a holographic mapping procedure over the delay space into a new coordinate system in order to achieve the objective. This mapping collapses the entire set of potential stability switching points on a manageably small number of hypersurfaces, which are explicitly defined in the new domain. This property considerably alleviates the problem, which is otherwise infinite dimensional, and therefore notoriously complex to handle. We further declare some unrecognized features of these switching hypersurfaces, that they are (a) encapsulated within a higher-dimensional cube with edges of length 2,, which we name the ,building block', and (b) the ,offspring' of this building block, which represent the secondary stability switchings, appear within the adjacent and identical building blocks (cubes) stacked up next to each other. The final outlook is an exclusive representation of stability for this general class of systems at any arbitrary point in the delay space. Two example case studies are also provided, which are not possible to analyze using any other methodology known to the authors. Copyright © 2007 John Wiley & Sons, Ltd. [source] The Permanency of Pulmonary Vein Isolation Using a Balloon Cryoablation CatheterJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2010HUMERA AHMED B.A. Chronic PV Isolation With the Cryoballoon.,Background: Because of its technical feasibility and presumed safety benefits, balloon cryoablation is being increasingly employed for pulmonary vein (PV) isolation. While acute isolation has been demonstrated in most patients, little data are available on the chronic durability of cryoballoon lesions. Methods and Results: Twelve atrial fibrillation patients underwent PV isolation using either a 23-mm or 28-mm cryoballoon. For each vein, after electrical isolation was verified with the use of a circular mapping cathether, 2 bonus balloon ablation lesions were placed. Gaps in balloon occlusion were overcome using either a spot cryocatheter or a "pull-down" technique. A prespecified second procedure was performed at 8,12 weeks to assess for long-term PV isolation. Acute PV isolation was achieved in all PVs in the patient cohort (n = 48 PVs), using the cryoballoon alone in 47/48 PVs (98%); a "pull-down" technique was employed for 5 PVs (1 right superior pulmonary vein, 2 right inferior pulmonary veins, and 2 left inferior pulmonary veins). The gap in the remaining vein was ablated with a spot cryocatheter. During the second mapping procedure, 42 of 48 PVs (88%) remained isolated. One vein had reconnected in 2 patients, while 2 veins had reconnected in another 2 patients. All PVs initially isolated with the "pull-down" technique remained isolated at the second procedure. Conclusions: Cryoballoon ablation allows for durable PV isolation with the use of a single balloon. With maintained chronic isolation in most PVs, it may represent a significant step toward consistent and lasting ablation procedures. (J Cardiovasc Electrophysiol, Vol. pp. 731-737, July 2010) [source] Internal Atrial Defibrillation During Electrophysiological Studies and Focal Atrial Fibrillation Ablation ProceduresPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2001MARTIN R. KARCH KARCH, M.R., et al.: Internal Atrial Defibrillation During Electrophysiological Studies and Focal Atrial Fibrillation Ablation Procedures. Induction of sustained AF during electrophysiological studies requires electrical cardioversion to restore sinus rhythm for continuation of the electrophysiological study and mapping procedure. The study included 104 consecutive patients (age 59 ± 12 years, 74 men), who were in stable sinus rhythm at the beginning of the electrophysiological study, underwent internal atrial defibrillation (IAD) of AF (> 15 minutes) that was induced during electrophysiological study. In 21 patients, AF was regarded to be the clinical problem (group I), and in the remaining 83 patients other arrhythmias represented the primary target of the electrophysiological study (group II). A 7.5 Fr cardioversion catheter (EP Medical) equipped with a distal array was used and placed in the left pulmonary artery and a proximal array of the same size was located along the lateral right atrial wall. All patients were successfully cardioverted with a mean energy of 6.2 ± 4.0 J. In 18 (78%) of 21 group I patients and in 12 (14%) of 81 group II patients, AF recurred 3.7 ± 3.4 and 2.4 ± 1.4 times during electrophysiological study, respectively. The IAD shock did not suppress focal activity, thus the mapping of atrial foci responsible for AF could be continued even after several IADs. No IAD related complications occurred during the study. In conclusion, (1) IAD can be safely and successfully performed during electrophysiological study without using narcotic drugs or high electric energies; (2) IAD does not suppress focal activity; and (3) even if AF recurs frequently during the electrophysiological study, IAD can be performed several times without significant time delay. [source] Mixture Generalized Linear Models for Multiple Interval Mapping of Quantitative Trait Loci in Experimental CrossesBIOMETRICS, Issue 2 2009Zehua Chen Summary Quantitative trait loci mapping in experimental organisms is of great scientific and economic importance. There has been a rapid advancement in statistical methods for quantitative trait loci mapping. Various methods for normally distributed traits have been well established. Some of them have also been adapted for other types of traits such as binary, count, and categorical traits. In this article, we consider a unified mixture generalized linear model (GLIM) for multiple interval mapping in experimental crosses. The multiple interval mapping approach was proposed by Kao, Zeng, and Teasdale (1999, Genetics152, 1203,1216) for normally distributed traits. However, its application to nonnormally distributed traits has been hindered largely by the lack of an efficient computation algorithm and an appropriate mapping procedure. In this article, an effective expectation,maximization algorithm for the computation of the mixture GLIM and an epistasis-effect-adjusted multiple interval mapping procedure is developed. A real data set, Radiata Pine data, is analyzed and the data structure is used in simulation studies to demonstrate the desirable features of the developed method. [source] Aerial photosieving of exposed gravel bars for the rapid calibration of airborne grain size mapsEARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2010Stephen J. Dugdale Abstract In recent years, fluvial remote sensing has seen considerable progress in terms of methods capable of system scale characterisation of river catchments. One key development is automated grain size mapping. It has been shown that high resolution aerial photography can be used to automatically produce grain size maps over entire rivers. However, current aerial grain size mapping procedures all require field calibration data. The collection of such data can be costly and problematic in the case of remote areas. This paper presents a method developed to remove the need for field based calibration data. Called ,aerial photosieving', this method consists of using the same very high resolution aerial imagery intended for grain size map production to visually measure particle sizes on-screen in order to provide calibration data. The paper presents a rigorous comparison of field-based photosieving calibration data and aerial photosieving calibration data. Statistical tests are used to demonstrate that aerial photosieving gives similar results when compared with field-based data with only a slight systematic overprediction. The new aerial photosieving method therefore simplifies the overall procedure required for the production of grain size maps and thus improves the cost-effectiveness and potential availability of this new fluvial remote sensing technology. Copyright © 2010 John Wiley &Sons, Ltd. [source] Unification of single-configuration seismic imaging processesGEOPHYSICAL PROSPECTING, Issue 2 2008H. Jaramillo ABSTRACT In this paper we derive an integral formula that encompasses all linear processes on seismic data. These include migration, demigration and residual migration, as well as data mapping procedures such as transformation to zero offset, inverse transformation to zero offset, residual transformation to zero offset and offset continuation. The derivation of the equation is different from all previous approaches to unification. Here we do not use a cascaded operation between two operators, but rather the superposition principle. In this regard, the derivation is not only more fundamental, but also simpler and more general. We study the kinematics and the dynamics of these processes and show that the signals can be reconstructed asymptotically either by finding the envelope of particular surfaces or by stacking energy along "adjoint" surfaces. For example, in the case of migration, the first set of surfaces are isochrons, while the "adjoint" surfaces are diffraction responses. In practice, the distinction between these two types of surfaces is equivalent to choosing the order of the computational loops with regard to the input and output seismic traces. [source] Spatial distribution of cloud coverINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2008Pedro Garcia Abstract Satellite systems and high-altitude platform systems working in Ka and V bands require the application of adaptive techniques in order to mitigate link degradations caused by atmospheric impairments such as those due to cloud cover. Among these techniques, resource sharing system techniques and site diversity need information on the spatial distribution of impairments caused by cloud cover, including the probability of simultaneous occurrence of adverse conditions in various regions. A study has been performed in Spain, within the framework of COST Action 280, to investigate the large-scale spatial distribution of cloud cover using synoptic meteorological data. Cloud cover distribution for individual sites and the spatial correlation properties for pairs of sites have been investigated. The geographical distributions of the values obtained from the statistical analysis have been represented in maps of contour lines using standard mapping procedures. Correlation parameters are expected to decrease with distance; however, the maps derived taking a given site as reference reveal a significant influence of climatic and geographic factors such as weather fronts, orography or the proximity to the sea. The statistics and maps obtained can be useful to optimize power sharing in multi-beam satellite systems, as suggested in this paper. Copyright © 2008 John Wiley & Sons, Ltd. [source] Human Histopathology of Electroanatomic Mapping After Cooled-Tip Radiofrequency Ablation to Treat Ventricular Tachycardia in Remote Myocardial InfarctionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2005THOMAS DENEKE M.D. Introduction: Catheter ablation of ventricular tachycardia (VT) in remote myocardial infarction (MI) often requires excessive mapping procedures. Documentation of the electrical substrate via electrogram amplitude may help to identify regions of altered myocardium resembling exit areas of reentrant VTs. Methods and Results: A patient with multiple symptomatic monomorphic VTs (biventricular ICD, remote MI) underwent electroanatomic substrate mapping (CARTOÔ) for VT ablation. Regions of scar (bipolar electrogram amplitudes ,0.5 mV), normal myocardium (,1.5 mV), and "altered" myocardium (0.5,1.5 mV) were identified. Ablation was directed to regions with "altered" myocardium based on pace map correlation. After ablation the clinical VT did not reoccur. The patient died due to worsening of heart failure 7 days afterward. During postmortal evaluation specified sites of electroanatomic mapping were correlated to histopathological findings. Annotated scar areas were documented to consist of areas with massive fibrosis (,80% of mural composition). Ablations were found to span through regions with intermediate fibrosis (21,79%) mapped as "altered" myocardium. Ablation produced transmural coagulation necrosis of mesh-like fibrotic tissue with interspersed remnants of myocardial cells up to a maximum depth of 7.0 mm. Subendocardial intramural bleedings were universal findings 7 days after ablation. Conclusions: Electroanatomic substrate mapping for VT ablation sufficiently identified regions of scar and normal myocardium. Regions with bipolar electrogram amplitudes between 0.5 and 1.5 mV were found to correlate to areas of "intermediate" fibrosis (21,79%) with only remnant strands of myocardial cells and were identified as target region for ablation. Cooled-tip endocardial radiofrequency ablation lead to transmural coagulation necrosis up to a depth of 7.0 mm. [source] | ||||||||||||||||