119 research outputs found
View update translation for XML
We study the problem of update translation for views on XML documents. More precisely, given an XML view definition and a user defined view update program, find a source update program that translates the view update without side effects on the view. Additionally, we require the translation to be defined on all possible source documents; this corresponds to HegnerĂą\u80\u99s notion of uniform translation. The existence of such translation would allow to update XML views without the need of materialization. The class of views we consider can remove parts of the document and rename nodes. Our update programs define the simultaneous application of a collection of atomic update operations among insertion/deletion of a subtree and node renaming. Such update programs are compatible with the XQuery Update Facility (XQUF) snapshot semantics. Both views and update programs are represented by recognizable tree languages. We present as a proof of concept a small fragment of XQUF that can be expressed by our update programs, thus allows for update propagation. Two settings for the update problem are studied: without source constraints, where all source updates are allowed, and with source constraints, where there is a restricted set of authorized source updates. Using tree automata techniques, we establish that without constraints, all view updates are uniformly translatable and the translation is tractable. In presence of constraints, not all view updates are uniformly translatable. However, we introduce a reasonable restriction on update programs for which uniform translation with constraints becomes possible
Subtree replacement systems
Theory and computer applications of subtree replacement system
New Results on Context-Free Tree Languages
Context-free tree languages play an important role in algebraic semantics and are applied in mathematical linguistics. In this thesis, we present some new results on context-free tree languages
Modal logics on rational Kripke structures
This dissertation is a contribution to the study of infinite graphs which can be
presented in a finitary way. In particular, the class of rational graphs is studied. The
vertices of a rational graph are labeled by a regular language in some finite alphabet
and the set of edges of a rational graph is a rational relation on that language. While
the first-order logics of these graphs are generally not decidable, the basic modal and
tense logics are.
A survey on the class of rational graphs is done, whereafter rational Kripke models
are studied. These models have rational graphs as underlying frames and are equipped
with rational valuations. A rational valuation assigns a regular language to each propositional
variable. I investigate modal languages with decidable model checking on rational
Kripke models. This leads me to consider regularity preserving relations to see if
the class can be generalised even further. Then the concept of a graph being rationally
presentable is examined - this is analogous to a graph being automatically presentable.
Furthermore, some model theoretic properties of rational Kripke models are examined.
In particular, bisimulation equivalences between rational Kripke models are studied.
I study three subclasses of rational Kripke models. I give a summary of the results
that have been obtained for these classes, look at examples (and non-examples in the
case of automatic Kripke frames) and of particular interest is finding extensions of the
basic tense logic with decidable model checking on these subclasses.
An extension of rational Kripke models is considered next: omega-rational Kripke
models. Some of their properties are examined, and again I am particularly interested
in finding modal languages with decidable model checking on these classes.
Finally I discuss some applications, for example bounded model checking on rational
Kripke models, and mention possible directions for further research
Tree Automata Techniques and Applications
International audienc
Proceedings
Proceedings of the NODALIDA 2011 Workshop
Constraint Grammar Applications.
Editors: Eckhard Bick, Kristin Hagen, Kaili MĂŒĂŒrisep, Trond Trosterud.
NEALT Proceedings Series, Vol. 14 (2011), vi+69 pp.
© 2011 The editors and contributors.
Published by
Northern European Association for Language
Technology (NEALT)
http://omilia.uio.no/nealt .
Electronically published at
Tartu University Library (Estonia)
http://hdl.handle.net/10062/19231
Analysis of the esophagogastric junction using the 3D high resolution manometry
Contexte & Objectifs : La manomĂ©trie perfusĂ©e conventionnelle et la manomĂ©trie haute rĂ©solution (HRM) ont permis le dĂ©veloppement dâune variĂ©tĂ© de paramĂštres pour mieux comprendre la motilitĂ© de l'Ćsophage et quantifier les caractĂ©ristiques de la jonction Ćsophago-gastrique (JOG). Cependant, l'anatomie de la JOG est complexe et les enregistrements de manomĂ©trie dĂ©tectent Ă la fois la pression des structures intrinsĂšques et des structures extrinsĂšques Ă l'Ćsophage. Ces diffĂ©rents composants ont des rĂŽles distincts au niveau de la JOG. Les pressions dominantes ainsi dĂ©tectĂ©es au niveau de la JOG sont attribuables au sphincter Ćsophagien infĂ©rieur (SOI) et aux piliers du diaphragme (CD), mais aucune des technologies manomĂ©triques actuelles nâest capable de distinguer ces diffĂ©rents composants de la JOG.
Lorsquâon analyse les caractĂ©ristiques de la JOG au repos, celle ci se comporte avant tout comme une barriĂšre antireflux. Les paramĂštres manomĂ©triques les plus couramment utilisĂ©s dans ce but sont la longueur de la JOG et le point dâinversion respiratoire (RIP), dĂ©fini comme le lieu oĂč le pic de la courbe de pression inspiratoire change de positif (dans lâabdomen) Ă nĂ©gatif (dans le thorax), lors de la classique manĆuvre de « pull-through ». Cependant, l'importance de ces mesures reste marginale comme en tĂ©moigne une rĂ©cente prise de position de lâAmerican Gastroenterology Association Institute (AGAI) (1) qui concluait que « le rĂŽle actuel de la manomĂ©trie dans le reflux gastro-Ćsophagien (RGO) est d'exclure les troubles moteurs comme cause des symptĂŽmes prĂ©sentĂ©s par la patient ».
Lors de la dĂ©glutition, la mesure objective de la relaxation de la JOG est la pression de relaxation intĂ©grĂ©e (IRP), qui permet de faire la distinction entre une relaxation normale et une relaxation anormale de la JOG. Toutefois, puisque la HRM utilise des pressions moyennes Ă chaque niveau de capteurs, certaines Ă©tudes de manomĂ©trie laissent suggĂ©rer quâil existe une zone de haute pression persistante au niveau de la JOG mĂȘme si un transit est mis en Ă©vidence en vidĂ©ofluoroscopie.
RĂ©cemment, la manomĂ©trie haute rĂ©solution « 3D » (3D-HRM) a Ă©tĂ© dĂ©veloppĂ©e (Given Imaging, Duluth, GA) avec le potentiel de simplifier l'Ă©valuation de la morphologie et de la physiologie de la JOG. Le segment « 3D » de ce cathĂ©ter de HRM permet l'enregistrement de la pression Ă la fois de façon axiale et radiale tout en maintenant une position fixe de la sonde, et Ă©vitant ainsi la manĆuvre de « pull-through ». Par consĂ©quent, la 3D-HRM devrait permettre la mesure de paramĂštres importants de la JOG tels que sa longueur et le RIP. Les donnĂ©es extraites de l'enregistrement fait par 3D-HRM permettraient Ă©galement de diffĂ©rencier les signaux de pression attribuables au SOI des Ă©lĂ©ments qui lâentourent. De plus, lâenregistrement des pressions de façon radiaire permettrait dâenregistrer la pression minimale de chaque niveau de capteurs et devrait corriger cette zone de haute pression parfois persistante lors la dĂ©glutition.
Ainsi, les objectifs de ce travail Ă©taient: 1) de dĂ©crire la morphologie de la JOG au repos en tant que barriĂšre antireflux, en comparant les mesures effectuĂ©es avec la 3D-HRM en temps rĂ©el, par rapport Ă celle simulĂ©es lors dâune manĆuvre de « pull-through » et de dĂ©terminer quelles sont les signatures des pressions attribuables au SOI et au diaphragme; 2) dâĂ©valuer la relaxation de la JOG pendant la dĂ©glutition en testant l'hypothĂšse selon laquelle la 3D-HRM permet le dĂ©veloppement dâun nouveau paradigme (appelĂ© « 3D eSleeve ») pour le calcul de lâIRP, fondĂ© sur lâutilisation de la pression radiale minimale Ă chaque niveau de capteur de pression le long de la JOG. Ce nouveau paradigme sera comparĂ© Ă une Ă©tude de transit en vidĂ©ofluoroscopie pour Ă©valuer le gradient de pression Ă travers la JOG.
MĂ©thodes : Nous avons utilisĂ© un cathĂ©ter 3D-HRM, qui incorpore un segment dit « 3D » de 9 cm au sein dâun cathĂ©ter HRM par ailleurs standard. Le segment 3D est composĂ© de 12 niveaux (espacĂ©s de 7.5mm) de 8 capteurs de pression disposĂ©s radialement, soit un total de 96 capteurs.
Neuf volontaires ont Ă©tĂ© Ă©tudiĂ©s au repos, oĂč des enregistrements ont Ă©tĂ© effectuĂ©s en temps rĂ©el et pendant une manĆuvre de « pull-through » du segment 3D (mobilisation successive du cathĂ©ter de 5 mm, pour que le segment 3D se dĂ©place le long de la JOG). Les mesures de la longueur du SOI et la dĂ©termination du RIP ont Ă©tĂ© rĂ©alisĂ©es. La longueur de la JOG a Ă©tĂ© mesurĂ©e lors du « pull-through » en utilisant 4 capteurs du segment 3D dispersĂ©s radialement et les marges de la JOG ont Ă©tĂ© dĂ©finies par une augmentation de la pression de 2 mmHg par rapport Ă la pression gastrique ou de lâĆsophage. Pour le calcul en temps rĂ©el, les limites distale et proximale de la JOG ont Ă©tĂ© dĂ©finies par une augmentation de pression circonfĂ©rentielle de 2 mmHg par rapport Ă la pression de l'estomac. Le RIP a Ă©tĂ© dĂ©terminĂ©e, A) dans le mode de tracĂ© conventionnel avec la mĂ©thode du « pull-through » [le RIP est la valeur moyenne de 4 mesures] et B) en position fixe, dans le mode de reprĂ©sentation topographique de la pression de lâĆsophage, en utilisant lâoutil logiciel pour dĂ©terminer le point d'inversion de la pression (PIP).
Pour l'Ă©tude de la relaxation de la JOG lors de la dĂ©glutition, 25 volontaires ont Ă©tĂ© Ă©tudiĂ©s et ont subi 3 Ă©tudes de manomĂ©trie (10 dĂ©glutitions de 5ml dâeau) en position couchĂ©e avec un cathĂ©ter HRM standard et un cathĂ©ter 3D-HRM. Avec la 3D-HRM, lâanalyse a Ă©tĂ© effectuĂ©e une fois avec le segment 3D et une fois avec une partie non 3D du cathĂ©ter (capteurs standard de HRM). Ainsi, pour chaque individu, l'IRP a Ă©tĂ© calculĂ©e de quatre façons: 1) avec la mĂ©thode conventionnelle en utilisant le cathĂ©ter HRM standard, 2) avec la mĂ©thode conventionnelle en utilisant le segment standard du cathĂ©ter 3D-HRM, 3) avec la mĂ©thode conventionnelle en utilisant le segment « 3D » du cathĂ©ter 3D-HRM, et 4) avec le nouveau paradigme (3D eSleeve) qui recueille la pression minimale de chaque niveau de capteurs (segment 3D).
Quatorze autres sujets ont subi une vidĂ©ofluoroscopie simultanĂ©e Ă lâĂ©tude de manomĂ©trie avec le cathĂ©ter 3D-HRM. Les donnĂ©es de pression ont Ă©tĂ© exportĂ©s vers MATLAB âą et quatre pressions ont Ă©tĂ© mesurĂ©es simultanĂ©ment : 1) la pression du corps de lâĆsophage, 2cm au-dessus de la JOG, 2) la pression intragastrique, 3) la pression radiale moyenne de la JOG (pression du eSleeve) et 4) la pression de la JOG en utilisant la pression minimale de chaque niveau de capteurs (pression du 3D eSleeve). Ces donnĂ©es ont permis de dĂ©terminer le temps permissif d'Ă©coulement du bolus (FPT), caractĂ©risĂ© par la pĂ©riode au cours de laquelle un gradient de pression existe Ă travers la JOG (pression Ćsophagienne > pression de relaxation de la JOG > pression gastrique). La prĂ©sence ou l'absence du bolus en vidĂ©ofluoroscopie et le FPT ont Ă©tĂ© codĂ©s avec des valeurs dichotomiques pour chaque pĂ©riode de 0,1 s. Nous avons alors calculĂ© la sensibilitĂ© et la spĂ©cificitĂ© correspondant Ă la valeur du FPT pour la pression du eSleeve et pour la pression du 3D eSleeve, avec la vidĂ©ofluoroscopie pour rĂ©fĂ©rence.
RĂ©sultats : Les enregistrements avec la 3D-HRM laissent suggĂ©rer que la longueur du sphincter Ă©valuĂ©e avec la mĂ©thode du « pull-through » Ă©tait grandement exagĂ©rĂ© en incorporant dans la mesure du SOI les signaux de pression extrinsĂšques Ă lâĆsophage, asymĂ©triques et attribuables aux piliers du diaphragme et aux structures vasculaires. Lâenregistrement en temps rĂ©el a permis de constater que les principaux constituants de la pression de la JOG au repos Ă©taient attribuables au diaphragme.
LâIRP calculĂ© avec le nouveau paradigme 3D eSleeve Ă©tait significativement infĂ©rieur Ă tous les autres calculs d'IRP avec une limite supĂ©rieure de la normale de 12 mmHg contre 17 mmHg pour lâIRP calculĂ© avec la HRM standard. La sensibilitĂ© (0,78) et la spĂ©cificitĂ© (0,88) du 3D eSleeve Ă©taient meilleurs que le eSleeve standard (0,55 et 0,85 respectivement) pour prĂ©dire le FPT par rapport Ă la vidĂ©ofluoroscopie.
Discussion et conclusion : Nos observations suggÚrent que la 3D-HRM permet l'enregistrement en temps réel des attributs de la JOG, facilitant l'analyse des constituants responsables de sa fonction au repos en tant que barriÚre antireflux. La résolution spatiale axiale et radiale du segment « 3D » pourrait permettre de poursuivre cette étude pour quantifier les signaux de pression de la JOG attribuable au SOI et aux structures extrinsÚques (diaphragme et artéfacts vasculaires). Ces attributs du cathéter 3D-HRM suggÚrent qu'il s'agit d'un nouvel outil prometteur pour l'étude de la physiopathologie du RGO.
Au cours de la dĂ©glutition, nous avons Ă©valuĂ© la faisabilitĂ© dâamĂ©liorer la mesure de lâIRP en utilisant ce nouveau cathĂ©ter de manomĂ©trie 3D avec un nouveau paradigme (3D eSleeve) basĂ© sur lâutilisation de la pression radiale minimale Ă chaque niveau de capteurs de pression. Nos rĂ©sultats suggĂšrent que cette approche est plus prĂ©cise que celle de la manomĂ©trie haute rĂ©solution standard. La 3D-HRM devrait certainement amĂ©liorer la prĂ©cision des mesures de relaxation de la JOG et cela devrait avoir un impact sur la recherche pour modĂ©liser la JOG au cours de la dĂ©glutition et dans le RGO.Background & Aims: Conventional water-perfused manometry and high resolution manometry permitted the development of a variety of manometric methodologies and metrics to understand the motility of the esophagus and to quantify esophagogastric junction (EGJ) characteristics. However, the anatomy in the area of the EGJ is complex and intraluminal manometry recordings detect pressure signals referable both to intrinsic esophageal structures and to adjacent extrinsic structures impinging on the esophagus. Both have distinct sphincteric mechanisms within the EGJ. The dominant pressure signals detected near the EGJ are attributable to the lower esophageal sphincter (LES) and the crural diaphragm (CD). However, neither of these technologies were able to distinguish between the different components of the EGJ.
When analyzing EGJ characteristics as a reflection of its competence against reflux, the more widely used manometric parameters are the EGJ length and the respiratory inversion point (RIP), defined as the location at which inspiratory pressure deflections change from positive (abdomen) to negative (chest). However, the significance of these metrics has not gained wide acceptance in the gastroenterology community as evident in a recent American Gastroenterology Association Institute (AGAI) Position Statement (1) concluding that âThe current role of manometry in gastroesophageal reflux disease (GERD) is to exclude motor disorders as a cause of the continued symptomsâ.
During deglutition, the objective quantitative measurement of EGJ relaxation, the integrative relaxation pressure (IRP), permits one to distinguish between normal and abnormal EGJ relaxation. However, comparison between spatial pressure variation plots and relaxation pressures derived from circumferentially averaged pressures suggest a persistent high pressure at the hiatal center during a period that flow is known to be occurring whereas this was not seen using nadir radial pressure data.
Recently, a 3D-high resolution manometry (3D-HRM) assembly (Given Imaging, Duluth, GA) has been developed with the potential to simplify the assessment of EGJ pressure morphology and physiology. The 3D segment of the array permits high resolution recording both axially and radially while maintaining a stationary sensor position. Consequently, 3D-HRM should allow for the measurement of important EGJ parameters such as length and RIP. Data extracted from the 3D-HRM recording may also allow differentiating pressure signals within the EGJ attributable to the intrinsic sphincter and to the surrounding elements. Moreover, 3D-HRM preserves the individual pressure values of each radially dispersed sensor within the array, permitting one to overcome the apparent persistent high pressure during the deglutitive relaxation.
Thus, the aims of this work were 1) to describe the EGJ pressure morphology at rest, comparing measures made with real time 3D-HRM to simulations of a conventional pull-through protocol and to define the pressure signatures attributable to the diaphragmatic and LES pressure components within the 3D-HRM recording; 2) to assess deglutitive EGJ relaxation by testing the hypothesis that the 3D-HRM array using an analysis paradigm based on finding the minimal radial pressure at each axial level (3D-eSleeve) should provide a representation of the luminal pressure gradient across the EGJ that is more relevant to predicting periods of trans-sphincteric flow using barium transit on fluoroscopy as the comparator. We also sought to adapt the IRP metric to the 3D-HRM array using the 3D-eSleeve principle (3D-IRP) and compare normative values obtained with this new paradigm to standard IRP calculations.
Methods: Patients were studied with a 3D-HRM assembly. The 3D-HRM assembly incorporated a 9 cm 3D-HRM segment into an otherwise standard HRM assembly; the 3D segment was comprised of 12 rings of 8 radially dispersed independent pressure sensors, spaced 7.5mm apart.
At rest, 9 volunteers were studied and recordings were done during a station pull-through of the 3D-HRM segment withdrawing it across the EGJ at 5 mm increments with each position held for 30s (sufficient to capture several respiratory cycles). Conventional measures of âLES lengthâ were made using 4 radially dispersed sensors within the 3D-HRM array, defining the margins of the sphincter by a 2 mmHg pressure increase relative to gastric or esophageal pressure. In the 3D-HRM, the proximal and distal limits of the EGJ were defined as the axial locations first detecting a 360° circumferential pressure increase of 2 mmHg relative to the stomach. RIP was determined, A) in the tracing mode: using the pull-through of 4 single sensors spaced 7.5 mm apart [RIP is the average value of 4 radially dispersed sensors] and B) in a stationary position using the software pressure inversion point (PIP) tool. In the esophageal pressure topography (EPT) mode, the tracing changed progressively from a thoracic pattern to an abdominal pattern, and the RIP was localized within the inversion zone with the PIP tool tracing.
For the study of the EGJ deglutitive relaxation, 25 volunteers underwent 3 consecutive 10-swallows protocols of 5 ml of water in the supine position with both the standard (once) and 3D-HRM (twice) devices in random sequence. During the 3D-HRM studies, the EGJ was measured once with the 3D-sleeve segment and once with a proximal (non-3D sleeve portion) of the device incorporating standard HRM sensors. For each subject, the IRP was calculated in four ways: 1) conventional method with the standard HRM device, 2) conventional method with a standard HRM segment of the 3D-HRM device, 3) conventional method using the 3D-HRM sleeve segment, and 4) a novel 3D-HRM eSleeve paradigm (3D-IRP) localizing the radial pressure minimum at each locus along the eSleeve. Fourteen additional subjects then underwent synchronized simultaneous videofluoroscopy and 3D-HRM (including two 5-ml barium swallows). Pressure data were exported to MATLABâą and four pressures were measured simultaneously: 1) esophageal body pressure 2cm above EGJ, 2) intragastric pressure, 3) radially average eSleeve pressure and 4) 3D-eSleeve pressure. Data were plotted to determine the flow permissive time (FPT) characterized as periods during which a pressure gradient through the EGJ is present (esophageal pressure > EGJ relaxation pressure (radial average or 3D-eSleeve paradigm) > gastric pressure). FPT was calculated during a 10s time window after upper sphincter relaxation. The presence or absence of bolus transit or FPT was coded with dichotomous values for each 0.1 s. We calculated the corresponding sensitivity and specificity for both radial average and 3D-eSleeve analyses of FPT with bolus transit evident on fluoroscopy being the reference.
Results: 3D-HRM recordings suggested that sphincter length assessed by a pull-through method greatly exaggerated the estimate of LES length by failing to discriminate among circumferential contractile pressure and asymmetric extrinsic pressure signals attributable to diaphragmatic and vascular structures. Real-time 3D EGJ recordings found that the dominant constituents of EGJ pressure at rest were attributable to the diaphragm.
The 3D-IRP was significantly less than all other calculations of IRP with the upper limit of normal being 12 mmHg vs. 17 mmHg for the standard IRP. The sensitivity (0.78) and the specificity (0.88) of the 3D-eSleeve were also better than the standard eSleeve (0.55 and 0.85, respectively) for predicting flow permissive time verified fluoroscopically.
Discussion & Conclusion: Our observations suggest that the 3D-HRM permits real-time recording of EGJ pressure morphology facilitating analysis of the EGJ constituents responsible for its function as a reflux barrier at rest. The axial and radial spatial resolution of the 9 cm 3D-HRM segment may permit further studies to differentiate pressure signals within the EGJ attributable to the LES and to extrinsic structures (diaphragm and vascular artifacts). These attributes of the 3D-HRM device suggest it to be a promising new tool in the study of GERD pathophysiology.
During deglutition, we evaluated the feasibility of improving the measurement of IRP utilizing a novel 3D-HRM assembly and a novel 3D-eSleeve concept based on finding the axial maximum of the radial minimum pressures at each sensor ring along the sleeve segment. Our findings suggest that this approach is more accurate than standard HRM and other methods that utilize a radially averaged pressure within the EGJ. Although we can only speculate on how much this will improve clinical management, 3D-HRM will certainly improve the accuracy of EGJ relaxation measurements and this will certainly impact research endeavors focused on modeling EGJ function during swallowing and reflux
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