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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
751

Mελέτη συντήρησης πνευμονικού μοσχεύματος χοίρου σε μοντέλο αυτομεταμόσχευσης πνεύμονα με τη χορήγηση επιφανειακού δραστικού παράγοντα

Κωλέτσης, Ευστράτιος Ν. 25 June 2007 (has links)
Η µεταµόσχευση πνεύµονα είναι µια αποδεκτή θεραπευτική λύση για τους ασθενείς µε πνευµονική νόσο τελικού σταδίου. Η πρώιµη δυσλειτουργία του µοσχεύµατος παραµένει µία από της κύριες αιτίες πρώιµης θνητότητας και νοσηρότητας. Το σύνδροµο ισχαιµίας – επαναιµάτωσης είναι ο υπεύθυνος κύριος παθογενετικός µηχανισµός. Η ακριβής αιτιοπαθολογία του συνδρόµου ισχαιµίας – επαναιµάτωσης δεν έχει πλήρως ερευνηθεί. Η πειραµατικές µεταµοσχεύσεις ως τώρα δεν µπόρεσαν να αποµονώσουν την κλινική εικόνα της βλάβης ισχαιµίας – επαναιµάτωσης, όπως είναι η υποξία, η σοβαρή βλάβη της ενδοθηλιακής διαπερατότητας και το γενικευµένο κυψελιδικό οίδηµα. Η ερευνητική µας οµάδα όπως και πολλές άλλες διεθνώς, χρησιµοποίησε ως τώρα το µοντέλο µεταµόσχευσης ενός πνεύµονα από το ένα ζώο σε άλλο. Ο πρώτος στόχος µας ήταν να δηµιουργήσουµε ένα σταθερό και επαναλήψιµο πειραµατικό πρωτόκολλο που θα µπορούσε να αναπαράγει τις τοπικές και συστηµατικές εκδηλώσεις του συνδρόµου ισχαιµίας- επαναιµάτωσης χωρίς όµως τη συµµετοχή της παθολογίας της απόρριψης, διατηρώντας παράλληλα τους λιγότερους χειρουργικούς χειρισµούς στο µόσχευµα. Είναι γνωστό ότι κατά τις πνευµονικές µεταµοσχεύσεις σε πειραµατικά µοντέλα εµφανίζονται αλλαγές στη σύνθεση και λειτουργικότητα του επιφανειοδραστικού παράγοντα και επιπλέον εξαγγείωση πρωτεϊνών του πλάσµατος στην κυψελίδα µε αποτέλεσµα την επιπρόσθετη επιβάρυνση της λειτουργίας του επιφανειοδραστικού παράγοντα. Οι αλλαγές στον επιφανειοδραστικό παράγοντα κατά τις πνευµονικές µεταµοσχεύσεις έχει προταθεί ότι συµµετέχουν σηµαντικά στην παθοφυσιολογία των βλαβών που σχετίζονται µε τη µεταµόσχευση. Έτσι µπορούµε να υποθέσουµε ότι διαδικασίες που θα µπορούσαν να σταθεροποιήσουν το σύστηµα του επιφανειοδραστικού παράγοντα θα οδηγούσαν πιθανότερα σε βελτίωση της λειτουργίας του µοσχεύµατος. Έχει αποδειχτεί ότι ο εξωγενώς χορηγούµενος επιφανειοδραστικός παράγοντας µιµείται τις επιφανειοδραστικές ιδιότητες του ενδογενούς. Ο δεύτερος στόχος της µελέτης µας ήταν να εξετάσουµε αν η εξωγενής χορήγηση επιφανειοδραστικού παράγοντα θα βελτίωνε τις ιδιότητες 103 του µοσχεύµατος αλλά και ποια επίδραση θα είχε η µη χορήγηση ενός ανοσοδιεγερτικού παράγοντα του επιφανειοδραστικού παράγοντα όπως είναι το SP-A επί του συνδρόµου ισχαιµίας επαναιµάτωσης. Χρησιµοποιήσαµε 14 νεαρούς χοίρους µέσου βάρους 27(±3,5) Kg εφαρµόζοντας ένα µοντέλο αυτοµεταµόσχευσης πνεύµονα in situ. Ο πνεύµονας παρασκευάστηκε και εκπλύθηκε µέσω της πνευµονικής αρτηρίας ορθόδροµα χρησιµοποιώντας διάλυµα U Wisconsin. Οι πνευµονικές φλέβες αποκλείστηκαν µετά τη συµβολή τους επί του αριστερού κόλπου και το υγρό συντήρησης παροχετεύτηκε από αντιστόµειο στον αριστερό κόλπο. Το µόσχευµα παρέµεινε σε θερµοκρασία 4-8 0C για διάστηµα 3 ωρών, διατηρώντας την κεντρική θερµοκρασία ανάµεσα 37 και 38.50 C. Ακολούθησε επαναιµάτωση του µοσχεύµατος. Στην οµάδα ελέγχου (Β) χορηγήθηκε ελεύθερος SP-A επιφανειοδραστικός παράγοντας 1.5 ml/Kg µέσω βρογχοσκοπίου, πριν τη θωρακοτοµή. Τα πειραµατόζωα θυσιάστηκαν 3 ώρες µετά την επαναιµάτωση. Μετά από 3 ώρες από την επαναιµάτωση, (οµάδα Α vs. Β) η PVRI ήταν 447.80 dyne.sec-1cm-5m-2 (±66.8) vs. 249.51(p<.001) ενώ το NO(*p<0.05,**p<0.001), η EPO και η πνευµονική ευενδοτότητα (**p<0.002) διατηρήθηκαν στατιστικά σηµαντικά. Η µέση κυψελιδική επιφάνεια ήταν 5280.84 (4991.1) µm2 vs. 3997,89 (3284.70) µm2(p<0.005). Η ιστολογική µελέτη έδειξε µικρότερη διήθηση µικροφάγων και λεµφοκυττάρων στην οµάδα χορήγησης επιφανειοδραστικού παράγοντα στο τέλος της επαναιµάτωσης. Συµπεράσµατα Το νέο αυτό µοντέλο ετερόπλευρης µεταµόσχευσης πνεύµονα αποδείχθηκε αξιόπιστο και αναπαρήγαγε όλη την παθολογία του συνδρόµου ισχαιµίας επαναιµάτωσης, χωρίς την επίδραση των µηχανισµών απόρριψης. Επιπλέον αποδείχτηκε ότι η προθεραπεία του µοσχεύµατος µε εξωγενή επιφανειοδραστικό παράγοντα µειώνει τη βλάβη ισχαιµίας-επαναιµάτωσης διατηρώντας όχι µόνο την πνευµονική ευενδοτότητα αλλά και το δείκτη πνευµονικών αντιστάσεων. Επιπλέον οι συγκεντρώσεις του NO και η 104 105 δραστηριότητα του EPO διατηρήθηκαν καλύτερα, ενώ και η µορφολογία της κυψελίδας φαίνεται να διατηρείται σηµαντικά καλύτερα. / Lung transplantation is a well accepted treatment for patients with end stage pulmonary disease. Early graft dysfunction remains one of the major causes of early morbidity and mortality, with reperfusion injury (RI) being the most responsible mechanism. The exact pathophysiology of RI in lung transplantation has not been fully evaluated and understood. Experimental transplantation after cold storage has been so far unable to duplicate the complete clinical picture of RI, such as, hypoxia, severe impairment of endothelial permeability, and frank alveolar oedema. We, among others, in our previous experimental work with pigs, had being using a single lung transplantation model. Our first aim has been to create a steady and reproducible experimental protocol that could demonstrate several parameters associated with the mechanisms of reperfusion injury, including impaired gas exchange, elevated pulmonary vascular resistant, local and systemic aspects of the reperfusion syndrome, but without the interference of the pathology concerning acute graft rejection, and with the minimal possible surgical manipulation of the graft. Animal studies have shown that lung transplantation is followed by changes to both synthesis and activity of surfactant. Surfactant alterations have been suggested to contribute significantly to the pathophysiology of transplantation-associated lung injuries. Therefore, procedures that stabilize the pulmonary surfactant system may prove to be crucial for optimal lung preservation. It has been demonstrated that exogenous surfactant mimics the surface-tension-lowering properties of natural lung surfactant. The second purpose of our study was to evaluate whether differences exist in lung preservation after pre-treatment (prior to graft retrieval) of donor lung with surfactant. We postulated that surfactant would lead to an enhanced preservation of the organ. Therefore, we used Surfactant, Beractant which is a natural bovine lung extract containing phospholipids, neutral lipids, fatty acids, and surfactantassociated proteins SP-B and SP-C to which colfosceril palmitate, palmitic acid, and tripalmiting are added in order to standardise the suspension. It should be noted that it does not contain SP-A. Furthermore, we assessed the effect of surfactant pretreatment to lung haemodynamics, respiratory parameters, serum and BALF nitric oxide and EPO levels and the microscopic morphology of the alveolar. Methods: Fourteen young female white pigs, mean weight 27(±3.5) Kg were used in a newly developed autotransplantation model with in-situ cold ischemia. The hilum was dissected free and the pericardium opened. University of Wisconsin solution was used for lung preservation flushed in an antegrade fashion through the left pulmonary artery. Pulmonary veins were clamped proximal to their origin at the left atrium and vent was created just distally to the clamp. The left main bronchus was clamped with the lung left semi-inflated. Interlobar fissure tissue temperature was monitored and maintained at 4-8 0C, while core temperature was kept between 37 and 38.50 C. After 3 hours of cold ischaemia clamps were removed and the lung was reperfused. In the study group (B, n=6) free-SP-A surfactant 1.5 ml/Kg, was administrated into the left main bronchus via flexible bronchoscopy, prior to thoracotomy. Animals were sacrificed after 3 hours of graft reperfusion. Results: At the end of reperfusion, (Control vs. study group) PVRI was 447.80 dyn.sec-1cm-5m-2 (±66.8) vs. 249.51(p<.001) and lung compliance was 14.83 ml/cm H2O (SD 1.78) vs. 18.91 (SD 0.73) (**p<0.002) were adequately preserved. Serum eosinophil peroxidase (EPO) activity persentence change was 18.6 +/- 5.6 vs. 116+/-52 p=0.001. In contrast, EPO activity in BALF was 180 +/- 21 vs 73+/-8, p=0.01. Finally, NO concentration in BALF was 0.75 μM =+/- 0. 06 vs. 0.91 +/- 0.15 p< 0,05 and serum NO were adequately preserved (*p<0.05,**p<0.001). The mean alveoli surface area estimated by computerized morphometry were 5280.84 (4991.1) μm2 vs. 3997,89 (3284.70) μm2(p<0.005). Histology revealed less macrophage and lymphocyte accumulation in the study group at the end of reperfusion. Conclusions: This new model of unilateral lung auto transplantation with a cold storage of the graft, proved to be very reliable in reproducing all aspects of ischemia/reperfusion injury, and we, therefore, propose its use in experimental studies dealing with this yet to be fully clarified clinical entity. Moreover it has demonstrated that pre-treatment of the donor lung with a surfactant agent reduced the ischemia and reperfusion injury by means of maintaining lung compliance and resulting in less respiratory and haemodynamic disturbances. Also, alveoli surface area, alveoli morphology, EPO and NO concentration were better preserved. These data supports the hypothesis that donor lung pretreatment with surfuctant has a beneficial effect on graft properties. Further studies are required before discussing potential benefits in clinical practice.
752

Reducing remodularization complexity through modular-objective decoupling

Chern, Rick 11 1900 (has links)
This dissertation defines "modular-objective coupling", and shows that programming language designs which imply reduced modular-objective coupling reduce complexity of remodularizations--behaviour-preserving restructurings for which the only intended goals are to change program source code structure. We explicitly distinguish between two points of view on program structure: modular structure--the structure of a program as a set of static text documents, and objective structure--the structure of a program as a dynamic computational model during execution. We define modular-objective coupling as the degree to which changes in modular structure imply changes to objective structure, for a given programming language. We use the term remodularization to refer to any behaviour-preserving source code restructuring, for which the only intended goal is to change modular structure. We argue that programming languages with strong modular-objective coupling introduce accidental complexity into remodularizations, by requiring complex objective structure changes to achieve intended modular structure changes. Our claim is that a programming language design which implies reduced modular-objective coupling reduces remodularization complexity in the language. To validate this claim, we first present SubjectJ, a subject-oriented programming system that extends Java. The design of Java implies strong modular-objective coupling, while SubjectJ is designed for reduced modular-objective coupling. We then perform a series of remodularization case studies comparing Java and SubjectJ. Our results suggest that remodularizations are less complex in SubjectJ.
753

Statinių ir dinaminių pratimų ryšys su 8-9 metų moksleivių sergamumu kvėpavimo sistemos ligomis / The relation of static and dinamic exersises with 8-9 year old children illness in respiratory diseases

Kotova, Anžela 21 June 2012 (has links)
Tyrimo problema. Medikams ir sveikatos specialistams nerimą kelia blogėjanti moksleivių sveikata. Lietuva pagal nepakankamai fiziškai aktyvių moksleivių dalį užima paskutiniąsias vietas. Daugėja moksleivių laiką leidžiančių prie kompiuterio ir televizoriaus ekranų. 2008 metų tyrimo duomenimis 50,4 proc. Lietuvos berniukų ir 64,4 proc. mergaičių yra nepakankamai fiziškai aktyvūs. Privalomojo sveikatos draudimo informacinės sistemos SVEIDRA duomenimis 2009 m. Lietuvoje buvo užregistruota 780 vaikų susirgimų ar traumų iš 1000. Vaikams (0–17 m.) dažniausiai registruojamos kvėpavimo sistemos ligos (567,8 sirgusiųjų 1000 vaikų 2009 m.), t.y. apie 57 proc. visų vaikų bent kartą buvo sirgę ūminėmis viršutinių kvėpavimo takų infekcijomis ir gripu. Kitomis ligomis vaikai sirgo gerokai mažiau. Lyginant 2008 m. ir 2009 m. rodiklius, reikia pabrėžti, kad 9,3 proc. padaugėjo vaikų sergančių ūminių viršutinių kvėpavimo takų infekcijomis ir gripu (Lietuvos sveikatos statistika, 2009 m.). Mokslinėje literatūroje neteko rasti straipsnių, analizuojančių statinių ir dinaminių pratimų poveikį vaikų sergamumui kvėpavimo sistemos ligomis. Darbo tikslas. Nustatyti statinių ir dinaminių pratimų ryšį su 8–9 metų moksleivių sergamumu kvėpavimo sistemos ligomis. Hipotezė. Statiniai ir dinaminiai pratimai turėtų sumažinti vaikų sergamumą kvėpavimo sistemos ligomis. Tyrimo metodai ir organizavimas. Tyrimas buvo atliekamas Panevėžio Vysk. K. Paltaroko gimnazijoje. Tyrimas vyko vienerius mokslo metus (201... [toliau žr. visą tekstą] / Research problem. Doctors and health experts are worried about deteriorating children’s health. Lithuania, by insufficient physical activity of students, takes the last place. The number of students who spend time at computer and TV screens is increasing. According to the 2008 research data, 50,4% of Lithuanian boys and 64,4% of girls are not physically active enough. According to the data of an information management system for the public healthcare service SVEIDRA, in 2009 in Lithuania out of 1000 children 780 cases of diseases and traumas were reported. For children (from 0 to17 years old) the respiratory system diseases are most commonly reported (567,8 children out of 1000 in 2009), i.e. about 57% of all children who had at least one record of acute upper respiratory tract infection and influenza. The number of other reported children’s diseases was significantly lower. To have compared the indicators of 2008 and 2009, it should be noted that the number of children who suffered from acute upper respiratory tract infections and influenza has risen by 9.3 percent (Lithuanian Health Statistics, 2009). Research aim. To determine the relation of static and dynamic exercises with 8–9–year–old children’s incidence of respiratory diseases. Hypothesis. Static and dynamic exercises are reducing the incidence of child respiratory diseases Research methods and organization. The research has been carried out in Panevezys, K. Paltarokas Gymnasium. It took one academic year (2010 – 201... [to full text]
754

Kineziterapijos ir kinezioteipavimo momentinis poveikis statinei ir dinaminei pusiausvyrai prieš priekinio kryžminio raiščio operaciją / The effect of physical therapy and instaneous kinesio taping for static and dynamic balance before anterior cruciate ligament surgery

Keršytė, Renata 10 September 2013 (has links)
Tyrimo objektas: Kineziterapijos ir kinezioteipavimo momentinis poveikis statinei ir dinaminei pusiausvyrai prieš priekinio kryžminio raiščio operaciją. Tyrimo tikslas: Nustatyti kineziterapijos ir kinezioteipavimo momentinį poveikį statinei bei dinaminei pusiausvyrai prieš priekinio kryžminio raiščio operaciją. Tyrimo uždaviniai: 1. Nustatyti kineziterapijos poveikį statinei ir dinaminei pusiausvyrai prieš priekinio kryžminio raiščio operaciją. 2. Nustatyti kinezioteipavimo momentinį poveikį statinei ir dinaminei pusiausvyrai taikant kineziterapiją prieš priekinio kryžminio raiščio operaciją. Tyrimo hipotezė: Manome, kad tiriamiesiems prieš priekinio kryžminio raiščio operaciją, taikyta kineziterapija pagerins statinę ir dinaminę pusiausvyrą. Be to, pusiausvyra stovint ant pažeistos kojos bus geresnė su kinezioteipu. Tyrimo rezultatai: Nustatėme, kad svyravimai Ax ir Ay ašyse, stovint ant pažeistos kojos, buvo statistiškai reikšmingai mažesni po kineziterapijos. Taip pat, po kineziterapijos pagerėjo pusiausvyra Ax ašyje stovint ant sveikos kojos. Pusiausvyra po šuolio stovint ant sveikos ir pažeistos kojos statistiškai reikšmingai pagerėjo po kineziterapijos Ay ašyje. Stovint ant pažeistos kojos su kinezioteipu, nustatėme statistiškai patikimą skirtumą tarp dinaminės pusiausvyros stovint ant pažeistos kojos be kinezioteipo ir su juo. Pusiausvyra pagerėjo Ax ir Ay ašyse. Išvados: 1. Po kineziterapijos pagerėjo statinė pusiausvyra pirmyn - atgal ir šonine kryptimis stovint ant... [toliau žr. visą tekstą] / Object of the study: The effect of physical therapy and instantaneous kinesio taping for static and dynamic balance before anterior cruciate ligament surgery. Aim of the study: To investigate effect of physical therapy and the instantaneous kinesio taping for static and dynamic balance before anterior cruciate ligament surgery. Goals of the study: 1. To investigate the effect of physical therapy for static and dynamic balance before anterior cruciate ligament surgery. 2. To investigate the instantaneous effect of kinesio taping for static and dynamic balance before anterior cruciate ligament surgery. Hypothesis of the study: We think that, static and dynamic balance will improve after physical therapy before anterior cruciate ligament surgery. Moreover, the balance of the injured limb will improve after instantaneous kinesio taping. Results of the study: We found that variations of standing on injured limb was significantly lower after physical therapy in Ax and Ay axis. Also, balance of healthy limb improved after physical therapy. Moreover, the balance after jump of injured and healthy leg improved in Ay axis after physical therapy. Dynamic balance improved with kinesio tape on injured limb before physical therapy. Conclusions: 1. Static balance forward - backward and side to side improved after physical therapy. Moreover, static balance standing on the injured limb improved side to side. Furthermore, dynamic side to side balance improved in both limbs after physical... [to full text]
755

Classification of muscle stretch receptor afferents in humans

Edin, Benoni B. January 1988 (has links)
The response patterns of human stretch receptors in the finger extensor muscles of the forearm were studied using the microneurography technique. Single-unit recordings were obtained from one-hundred and twenty-four afferents. A procedure was developed to classify the units in muscle spindle primary afferents, secondary afferents, and Golgi tendong organ afferents. The procedure allows an objective and reproducible classification on the basis of the afferents’ responses to a series of tests which individually are non-conclusive. It was demonstrated that maximal twitch contractions can be elicited in the finger extensor muscles of the forearm, without causing undue discomfort to the subjects, or hazarding the single-unit recording. The response of the units to this test allowed, in most cases but not always, a separation in muscle spindle and tendon organ afferents. Thus the test was not adequate for an unequivocal classification. Three discrete response parameters were extracted from ramp-and-hold stretches, viz. the presence or absence of an initial burst and a deceleration response, and prompt silencing at slow muscle shortening. The distributions of the parameters were significantly different among the three unit types. These parameters which were pair-wise independent constituted a set of considerable discriminative power. It was shown that human muscle spindles have about the same static position sensitivity to fractional muscle stretch as previously found in animals. Stretch sensitization was demonstrated by rapid, repeated stretches of the muscle which enhanced the réponse to subsequent slow stretches of muscle spindles. Sensitization was different with primary and secondary muscle spindle afferents whereas Golgi tendon organ afferents never displayed stretch sensitization. One-to-one driving with small-amplitude sinusoidal stretches superimposed on ramp-and- hold stretches was almost exclusively seen with primary muscle spindle afferents, whereas secondaries seldom and tendon organ afferents never displayed driving. The afferent responses during slowly increasing isometric contractions and rapid relaxations were analysed. An increased discharge rate on relaxation was common among spindle afferents whereas it was never seen in tendon organs afferents. Two separate groups of spindles afferents were found with regard to fusimotor recruitment. The largest group was recruited at rather low and variable contractile forces whereas the smaller group was not recruited at all. The proportions of the three unit types, spindle primary, spindle secondary, and Golgi tendon organ afferents were estimated from a preliminary classification and the distribution of the eight response features were analyzed for each class of afferents. On the basis of these estimates and the response pattern of the individual unit Bayes’ theorem was used to calculate the probabilities that the unit was a spindle primary, a spindle secondary, or a tendon organ afferent. Estimates indicate that about 19 out of 20 muscle afferents are correctly classified when all eight features are analyzed. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1988, härtill 6 uppsatser.</p> / digitalisering@umu
756

Understanding and Improving Object-Oriented Software Through Static Software Analysis

Irwin, Warwick Allan January 2007 (has links)
Software engineers need to understand the structure of the programs they construct. This task is made difficult by the intangible nature of software, and its complexity, size and changeability. Static analysis tools can help by extracting information from source code and conveying it to software engineers. However, the information provided by typical tools is limited, and some potentially rich veins of information - particularly metrics and visualisations - are under-utilised because developers cannot easily acquire or make use of the data. This thesis documents new tools and techniques for static analysis of software. It addresses the problem of generating parsers directly from standard grammars, thus avoiding the com-mon practice of customising grammars to comply with the limitations of a given parsing al-gorithm, typically LALR(1). This is achieved by a new parser generator that applies a range of bottom-up parsing algorithms to produce a hybrid parsing automaton. Consequently, we can generate more powerful deterministic parsers - up to and including LR(k) - without incurring the combinatorial explosion that makes canonical LR(k) parsers impractical. The range of practical parsers is further extended to include GLR, which was originally developed for natural language parsing but is shown here to also have advantages for static analysis of programming languages. This emphasis on conformance to standard grammars im-proves the rigour of static analysis tools and allows clearer definition and communication of derived information, such as metrics. Beneath the syntactic structure of software (exposed by parsing) lies the deeper semantic structure of declarations, scopes, classes, methods, inheritance, invocations, and so on. In this work, we present a new tool that performs semantic analysis on parse trees to produce a comprehensive semantic model suitable for processing by other static analysis tools. An XML pipeline approach is used to expose the syntactic and semantic models of the software and to derive metrics and visualisations. The approach is demonstrated producing several types of metrics and visualisations for real software, and the value of static analysis for informing software engineering decisions is shown.
757

Bearing Capacity and Settlement Behaviour of Footings Subjected to Static and Seismic Loading Conditions in Unsaturated Sandy Soils

Mohamed, Fathi Mohamed Omar 25 February 2014 (has links)
Several studies were undertaken by various investigators during the last five decades to better understand the engineering behaviour of unsaturated soils. These studies are justified as more than 33% of soils worldwide are found in either arid or semi-arid regions with evaporation losses exceeding water infiltration. Due to this reason, the natural ground water table in these regions is typically at a greater depth and the soil above it is in a state of unsaturated conditions. Foundations of structures such as the housing subdivisions, multi-storey buildings, bridges, retaining walls, silos, and other infrastructure constructed in these regions in sandy soils are usually built within the unsaturated zone (i.e., vadose zone). Limited studies are reported in the literature to understand the influence of capillary stresses (i.e., matric suction) on the bearing capacity, settlement and liquefaction potential of unsaturated sands. The influence of matric suction in the unsaturated zone of the sandy soils is ignored while estimating or evaluating bearing capacity, settlement and liquefaction resistance in conventional engineering practice. The focus of the research presented in the thesis has been directed towards better understanding of these aspects and providing rational and yet simple tools for the design of shallow foundations (i.e., footings) in sands under both static and dynamic loading conditions. Terzaghi (1943) or Meyerhof (1951) equations for bearing capacity and Schmertmann et al. (1978) equation for settlement are routinely used by practicing engineers for sandy soils based on saturated soil properties. The assumption of saturated conditions leads to conservative estimates for bearing capacity; however, neglecting the influence of capillary stresses contributes to unreliable estimates of settlement or differential settlement of footings in unsaturated sands. There are no studies reported in the literature on how capillary stresses influence liquefaction, bearing capacity and settlement behavior in earthquake prone regions under dynamic loading conditions. An extensive experimental program has been undertaken to study these parameters using several specially designed and constructed equipment at the University of Ottawa. The influence of matric suction, confinement and dilation on the bearing capacity of model footings in unsaturated sand was determined using the University of Ottawa Bearing Capacity Equipment (UOBCE-2011). Several series of plate load tests (PLTs) were carried out on a sandy soil both under saturated and unsaturated conditions. Based on these studies, a semi-empirical equation has been proposed for estimating the variation of bearing capacity with respect to matric suction. The saturated shear strength parameters and the soil water characteristic curve (SWCC) are required for using the proposed equation. This equation is consistent with the bearing capacity equation originally proposed by Terzaghi (1943) and later extended by Meyerhof (1951) for saturated soils. Chapter 2 provides the details of these studies. The cone penetration test (CPT) is conventionally used for estimating the bearing capacity of foundations because it is simple and quick, while providing continuous records with depth. In this research program, a cone penetrometer was specially designed to investigate the influence of matric suction on the cone resistance in a controlled laboratory environment. Several series of CPTs were conducted in sand under both saturated and unsaturated conditions. Simple correlations were proposed from CPTs data to relate the bearing capacity of shallow foundations to cone resistance in saturated and unsaturated sands. The details of these studies are presented and summarized in Chapter 3. Standard penetration tests (SPTs) and PLTs were conducted in-situ sand deposit at Carp region in Ottawa under both saturated and unsaturated conditions. The test results from the SPTs and PLTs at Carp were used along with other data from the literature for developing correlations for estimating the bearing capacity of both saturated and unsaturated sands. The proposed SPT-CPT-based technique is simple and reliable for estimation of the bearing capacity of footings in sands. Chapter 4 summarizes the details of these investigations. Empirical relationships were proposed using the CPTs data to estimate the modulus of elasticity of sands for settlement estimation of footings in both saturated and unsaturated sands. This was achieved by modifying the Schmertmann et al. (1978) equation, which is conventionally used for settlement estimations in practice. Comparisons are provided between the three CPT-based methods that are commonly used for settlement estimations in practice and the proposed method for seven large scale footings in sandy soils. The results of the comparisons show that the proposed method provides better estimations for both saturated and unsaturated sands. Chapter 5 summarizes the details of these studies. A Flexible Laminar Shear Box (FLSB of 800-mm3 in size) was specially designed and constructed to simulate and better understand the behaviour of model surface footing under seismic loads taking account of the influence of matric suction in an unsaturated sandy soil. The main purpose of using the FLSB is to simulate realistic in-situ soils behaviour during earthquake ground shaking. The FLSB test setup with model footing was placed on unidirectional 1-g shake table (aluminum platform of 1000-mm2 in size) during testing. The resistance of unsaturated sand to deformations and liquefaction under seismic loads was investigated. The results of the study show that matric suction offers significant resistance to liquefaction and settlement of footings in sand. Details of the equipment setup, test procedure and results of this study are presented in Chapter 6. Simple techniques are provided in this thesis for estimating the bearing capacity and settlement behaviour of sandy soils taking account of the influence of capillary stresses (i.e., matric suction). These techniques are consistent with the methods used in conventional geotechnical engineering practice. The studies show that even low values of capillary stresses (i.e., 0 to 5 kPa) increases the bearing capacity by two to four folds, and the settlement of footings not only decreases significantly but also offers resistance to liquefaction in sands. These studies are promising and encouraging to use ground improvement techniques; such as capillary barrier techniques to maintain capillary stresses within the zone of influence below shallow foundations. Such techniques, not only contribute to the increase of bearing capacity, they reduce settlement and alleviate problems associated with earthquake effects in sandy soils.
758

Static analysis of numerical properties in the presence of pointers

Fu, Zhoulai 22 July 2013 (has links) (PDF)
The fast and furious pace of change in computing technology has become an article of faith for many. The reliability of computer-based systems cru- cially depends on the correctness of its computing. Can man, who created the computer, be capable of preventing machine-made misfortune? The theory of static analysis strives to achieve this ambition. The analysis of numerical properties of programs has been an essential research topic for static analysis. These kinds of properties are commonly modeled and handled by the concept of numerical abstract domains. Unfor- tunately, lifting these domains to heap-manipulating programs is not obvious. On the other hand, points-to analyses have been intensively studied to an- alyze pointer behaviors and some scale to very large programs but without inferring any numerical properties. We propose a framework based on the theory of abstract interpretation that is able to combine existing numerical domains and points-to analyses in a modular way. The static numerical anal- ysis is prototyped using the SOOT framework for pointer analyses and the PPL library for numerical domains. The implementation is able to analyze large Java program within several minutes. The second part of this thesis consists of a theoretical study of the com- bination of the points-to analysis with another pointer analysis providing information called must-alias. Two pointer variables must alias at some pro- gram control point if they hold equal reference whenever the control point is reached. We have developed an algorithm of quadruple complexity that sharpens points-to analysis using must-alias information. The algorithm is proved correct following a semantics-based formalization and the concept of bisimulation borrowed from the game theory, model checking etc.
759

Development of a new service-oriented modelling method for information systems analysis and design

Gustiené, Prima January 2010 (has links)
This thesis presents a new modelling method for information systems analysis and design, where the concept of service and the principles of service orientation are used for integrated modelling and reasoning about information systems architectures across organisational and technical systems boundaries. The concept of service enables cohesion of the intersubjective and objective modelling traditions by using a single type of diagram that facilitates detection of semantic inconsistency, incompleteness, ambiguity and discontinuity between the static and dynamic aspects of information systems specifications. The thesis is focused on three research topics, which are fundamental to the development of a new service-oriented modelling method. The first research topic concerns a pragmatic-driven specification of information systems. It clarifies answers to the research question: How can a conceptual modelling process be driven by pragmatic considerations? The second research topic provides a service-oriented modelling foundation for information systems analysis and design. It answers the research questions: How can the concept of service be used explicitly for the analysis and design of information systems and how can the static and dynamic aspects of information systems specifications be integrated at the conceptual level? The third research topic presents transition principles to implementation-specific design and answers the research question: How can service-oriented conceptual representations be aligned with implementation-specific design? The thesis contributes with a new knowledge to the area of conceptual modelling of information systems. The service-oriented modelling method consists of the modelling process, modelling language and techniques for the analysis and design of information systems on three levels of abstraction: pragmatic, semantic and syntactic. These three levels are necessary for a holistic understanding of enterprise architecture by stakeholders. The advantage of the service-oriented modelling method is that it can help to control traceability from information system design to original requirements. The method facilitates the semantic integration of the structural, behavioural and interactive aspects of information systems conceptual representations by using a single diagram type. The modelling language provides service-oriented constructs that are fundamental to building the major systems analysis patterns. The service-oriented modelling process contributes with seven steps of incremental design, which justifies various information systems components. The method provides the basis for a gradual and systematic way of modelling and an understanding of how pragmatic, semantic and logical information system requirements are linked together. The possibility to detect and eliminate undesirable characteristics of service-oriented diagrams can help to improve communication among stakeholders. Service-oriented specifications are computation-neutral and therefore they are more comprehensible for business analysis experts in comparison to implementation specific graphical representations of information systems. Finally, this thesis presents the challenges for future research, one of which is the development of the automated tools for the alignment of business models with implementation-specific information systems specifications.
760

The Relation Among Students&amp / #8217 / Gender, Socio-economic Status, Interest, Experience And Misconceptions About Static Electricity At Ninth Grade Level

Kocyigit, Senkoc 01 December 2003 (has links) (PDF)
This study was designed to identify ninth grade students&amp / #8217 / misconceptions about static electricity concept and to determine relationship among students&amp / #8217 / gender, socio-economic status, interest, experience with students&amp / #8217 / misconceptions about static electricity. For this study, Static Electricity Concept Test (SECT) and Socio-Economic Status, Interest and Experience Questionnaire about Static Electricity (SESIEQ) were developed to assess students&amp / #8217 / misconceptions related to static electricity and their socio-economic status, interest and experience about static electricity, respectively. This study was carried out during 2002-2003 spring semester with 1260 ninth grade students from 9 Anatolian and regular high schools in &Ccedil / ankaya and Mamak districts of Ankara. Findings of the concept test indicated that many students had misconceptions about static electricity. Negative and significant relationships among students&amp / #8217 / gender, socio-economic status, interest, experience and misconception scores were found. The difference between misconception scores of male and female students was significant in favor of males. However, when the data were analyzed using ANCOVA while controlling students&amp / #8217 / socio-economic status, interest in static electricity and experience about static electricity, no difference was observed between the misconception scores of male and female students.

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