Modelling and Animation using Partial Differential Equations. Geometric modelling and computer animation of virtual characters using elliptic partial differential equations.

This work addresses various applications pertaining to the design, modelling and animation of parametric surfaces using elliptic Partial Differential Equations (PDE) which are produced via the PDE method. Compared with traditional surface generation techniques, the PDE method is an effective technique that can represent complex three-dimensional (3D) geometries in terms of a relatively small set of parameters. A PDE-based surface can be produced from a set of pre-configured curves that are used as the boundary conditions to solve a number of PDE. An important advantage of using this method is that most of the information required to define a surface is contained at its boundary. Thus, complex surfaces can be computed using only a small set of design parameters. In order to exploit the advantages of this methodology various applications were developed that vary from the interactive design of aircraft configurations to the animation of facial expressions in a computer-human interaction system that utilizes an artificial intelligence (AI) bot for real time conversation. Additional applications of generating cyclic motions for PDE based human character integrated in a Computer-Aided Design (CAD) package as well as developing techniques to describe a given mesh geometry by a set of boundary conditions, required to evaluate the PDE method, are presented. Each methodology presents a novel approach for interacting with parametric surfaces obtained by the PDE method. This is due to the several advantages this surface generation technique has to offer. Additionally, each application developed in this thesis focuses on a specific target that delivers efficiently various operations in the design, modelling and animation of such surfaces.The project files will not be available online

Epigenetic and neurological effects and safety of high-dose nicotinamide in patients with Friedreich's ataxia: an exploratory, open-label, dose-escalation study

Background: Friedreich's ataxia is a progressive degenerative disorder caused by deficiency of the frataxin protein. Expanded GAA repeats within intron 1 of the frataxin (FXN) gene lead to its heterochromatinisation and transcriptional silencing. Preclinical studies have shown that the histone deacetylase inhibitor nicotinamide (vitamin B3) can remodel the pathological heterochromatin and upregulate expression of FXN. We aimed to assess the epigenetic and neurological effects and safety of high-dose nicotinamide in patients with Friedreich's ataxia. Methods: In this exploratory, open-label, dose-escalation study in the UK, male and female patients (aged 18 years or older) with Friedreich's ataxia were given single doses (phase 1) and repeated daily doses of 2–8 g oral nicotinamide for 5 days (phase 2) and 8 weeks (phase 3). Doses were gradually escalated during phases 1 and 2, with individual maximum tolerated doses used in phase 3. The primary outcome was the upregulation of frataxin expression. We also assessed the safety and tolerability of nicotinamide, used chromatin immunoprecipitation to investigate changes in chromatin structure at the FXN gene locus, and assessed the effect of nicotinamide treatment on clinical scales for ataxia. This study is registered with ClinicalTrials.gov, number NCT01589809. Findings: Nicotinamide was generally well tolerated; the main adverse event was nausea, which in most cases was mild, dose-related, and resolved spontaneously or after dose reduction, use of antinausea drugs, or both. Phase 1 showed a dose-response relation for proportional change in frataxin protein concentration from baseline to 8 h post-dose, which increased with increasing dose (p=0·0004). Bayesian analysis predicted that 3·8 g would result in a 1·5-times increase and 7·5 g in a doubling of frataxin protein concentration. Phases 2 and 3 showed that daily dosing at 3·5–6 g resulted in a sustained and significant (p<0·0001) upregulation of frataxin expression, which was accompanied by a reduction in heterochromatin modifications at the FXN locus. Clinical measures showed no significant changes. Interpretation: Nicotinamide was associated with a sustained improvement in frataxin concentrations towards those seen in asymptomatic carriers during 8 weeks of daily dosing. Further investigation of the long-term clinical benefits of nicotinamide and its ability to ameliorate frataxin deficiency in Friedreich's ataxia is warranted

Investigation of the Performance of the New Orleans Flood Protection System in Hurricane Katrina on August 29, 2005: Volume 1

This report presents the results of an investigation of the performance of the New Orleans regional flood protection system during and after Hurricane Katrina, which struck the New Orleans region on August 29, 2005. This event resulted in the single most costly catastrophic failure of an engineered system in history. Current damage estimates at the time of this writing are on the order of $100 to$200 billion in the greater New Orleans area, and the official death count in New Orleans and southern Louisiana at the time of this writing stands at 1,293, with an additional 306 deaths in nearby southern Mississippi. An additional approximately 300 people are currently still listed as “missing”; it is expected that some of these missing were temporarily lost in the shuffle of the regional evacuation, but some of these are expected to have been carried out into the swamps and the Gulf of Mexico by the storm’s floodwaters, and some are expected to be recovered in the ongoing sifting through the debris of wrecked homes and businesses, so the current overall regional death count of 1,599 is expected to continue to rise a bit further. More than 450,000 people were initially displaced by this catastrophe, and at the time of this writing more than 200,000 residents of the greater New Orleans metropolitan area continue to be displaced from their homes by the floodwater damages from this storm event. This investigation has targeted three main questions as follow: (1) What happened?, (2) Why?, and (3) What types of changes are necessary to prevent recurrence of a disaster of this scale again in the future? To address these questions, this investigation has involved: (1) an initial field reconnaissance, forensic study and data gathering effort performed quickly after the arrival of Hurricanes Katrina (August 29, 2005) and Rita (September 24, 2005), (2) a review of the history of the regional flood protection system and its development, (3) a review of the challenging regional geology, (4) detailed studies of the events during Hurricanes Katrina and Rita, as well as the causes and mechanisms of the principal failures, (4) studies of the organizational and institutional issues affecting the performance of the flood protection system, (5) observations regarding the emergency repair and ongoing interim levee reconstruction efforts, and (6) development of findings and preliminary recommendations regarding changes that appear warranted in order to prevent recurrence of this type of catastrophe in the future. In the end, it is concluded that many things went wrong with the New Orleans flood protection system during Hurricane Katrina, and that the resulting catastrophe had it roots in three main causes: (1) a major natural disaster (the Hurricane itself), (2) the poor performance of the flood protection system, due to localized engineering failures, questionable judgments, errors, etc. involved in the detailed design, construction, operation and maintenance of the system, and (3) more global “organizational” and institutional problems associated with the governmental and local organizations responsible for the design, construction, operation, maintenance and funding of the overall flood protection system

TLR7 gain-of-function genetic variation causes human lupus

Although circumstantial evidence supports enhanced Toll-like receptor 7 (TLR7) signalling as a mechanism of human systemic autoimmune disease evidence of lupus-causing TLR7 gene variants is lacking. Here we describe human systemic lupus erythematosus caused by a TLR7 gain-of-function variant. TLR7 is a sensor of viral RNA and binds to guanosine. We identified a de novo, previously undescribed missense TLR7Y264H variant in a child with severe lupus and additional variants in other patients with lupus. The TLR7Y264H variant selectively increased sensing of guanosine and 2',3'-cGMP1 and was sufficient to cause lupus when introduced into mice. We show that enhanced TLR7 signalling drives aberrant survival of B cell receptor (BCR)-activated B cells, and in a cell-intrinsic manner, accumulation of CD11c+ age-associated B cells and germinal centre B cells. Follicular and extrafollicular helper T cells were also increased but these phenotypes were cell-extrinsic. Deficiency of MyD88 (an adaptor protein downstream of TLR7) rescued autoimmunity, aberrant B cell survival, and all cellular and serological phenotypes. Despite prominent spontaneous germinal-centre formation in Tlr7Y264H mice, autoimmunity was not ameliorated by germinal-centre deficiency, suggesting an extrafollicular origin of pathogenic B cells. We establish the importance of TLR7 and guanosine-containing self-ligands for human lupus pathogenesis, which paves the way for therapeutic TLR7 or MyD88 inhibition

Adaptation and alignment of interface design paradigms in service-oriented architectures

The area of Service-Oriented Computing (SOC) has emerged as a computing paradigm for designing and constructing distributed systems. In this paradigm, software components provide and consume services, exposed through service interfaces. The de facto approach for service interface design in service-oriented computing follows a procedure-oriented paradigm, where service capabilities are decomposed and exposed as collections of related service operations, which can be invoked using a traditional remote procedure call (RPC) type of access. However, over the past few years we have witnessed a paradigm shift on the programming models and the architectural styles that have been used to design and implement large-scale service-oriented systems. This paradigm shift is attributed to the adoption of the resource-oriented service design paradigm, which is inspired by architectural approaches and properties pertinent to the World Wide Web. Such resource-oriented design paradigm aims for enhancing interoperability and simplicity through uniformity, improving scalability, allowing for loose coupling and limiting dependence on shifting technology standards. As a result, the Representational State Transfer (REST), which has been proposed as an architectural style that establishes the resource-oriented nature of the Web's architecture, gained considerable attention in the service engineering community, since it aims for an efficient bridging of enterprise software systems and the Web. An open debate and discussion in the software engineering community focuses on how to properly apply REST not only for the development of new enterprise systems but also, for the adaptation of existing service-oriented systems so that service providers can offer their service capabilities also through resource-oriented interfaces. Furthermore, the co-existence of procedure-oriented services and resource-oriented services in enterprise environments, introduces a number of new challenges pertaining to developing, maintaining and evolving dual interface service-oriented applications. In this dissertation, we investigate two main problems. The first problem deals with issues and challenges related to the adaptation of procedure-oriented service systems to RESTful architectures. For this purpose, we propose a process and a framework, which allow for the analysis, modeling, extraction, and transformation of procedure-oriented interface models in order to identify and yield corresponding resource-oriented interfaces. The second problem deals with the alignment of procedure-oriented and resource-oriented service interfaces. More specifically, we examine how the two paradigms are related conceptually and architecturally, and we propose a method and a framework for deciding substitutability between services that offer similar functionality but are exposed through different interface paradigms (paradigm-divergent interfaces). The solution to these problems is important as first, it allows for a methodological analysis of how procedure-orientation and resource-orientation relate to each other, second, it allows for the design and implementation of run-time frameworks that can be used to offer service capabilities in dual interfaces and third, it allows for the provider-side consistent co-evolution of dual service interfaces and for the consumer-side substitution validation when alternative services need to be considered. The proposed approaches and frameworks are evaluated through a series of experiments and case studies. The results indicate that the proposed approaches are tractable, can be used to develop run-time procedure-oriented to resource-oriented interface adapters, and provide a method to efficiently assess substitutability and alignment of paradigm-divergent service interfaces.Η περιοχή της Υπηρεσιοστρεφούς Υπολογιστικής (Service-Oriented Computing) αναδύθηκε ως ένα υπολογιστικό μοντέλο για τον σχεδιασμό και την κατασκευή κατανεμημένων συστημάτων. Σε αυτό το μοντέλο, τα δομοστοιχεία λογισμικού παρέχουν και καταναλώνουν υπηρεσίες, οι οποίες εκτίθενται μέσω διεπαφών. Η καθιερωμένη προσέγγιση για τον σχεδιασμό διεπαφών υπηρεσιών στην υπηρεσιοστρεφή υπολογιστική ακολουθεί το υπόδειγμα προσανατολισμένο σε διαδικασίες (ΠΣΔ) (procedure-oriented paradigm), στο οποίο οι δυνατότητες μιας υπηρεσίας αναλύονται και εκτίθενται ως συλλογές σχετιζόμενων λειτουργιών που μπορούν να κληθούν, ακολουθώντας το παραδοσιακό μοντέλο πρόσβασης απομακρυσμένων κλήσεων διαδικασιών. Παρόλα αυτά, κατά τη διάρκεια των τελευταίων ετών έχουμε γίνει μάρτυρες μια στροφής σε ό,τι αφορά τα υποδείγματα προγραμματιστικών μοντέλων και των αρχιτεκτονικών στυλ που χρησιμοποιούνται για τον σχεδιασμό και την υλοποίηση μεγάλης κλίμακας υπηρεσιοστρεφών συστημάτων. Αυτή η στροφή αποδίδεται στην υιοθέτηση του υποδείγματος προσανατολισμένου σε πόρους (ΠΣΠ) (resource-oriented paradigm) το οποίο είναι εμπνευσμένο από αρχιτεκτονικές προσεγγίσεις και ιδιότητες συναφείς με τον Παγκόσμιο Ιστό. Το σχεδιαστικό υπόδειγμα ΠΣΠ στοχεύει στη βελτίωση της διαλειτουργικότητας, στην απλότητα μέσω της ομοιομορφίας, στην ενίσχυση των δυνατοτήτων κλιμάκωσης, στη μείωση της σύζευξης μεταξύ των δομοστοιχείων και στον περιορισμό της εξάρτησης από μεταβαλλόμενα τεχνολογικά πρότυπα. Ως αποτέλεσμα, το αρχιτεκτονικό στυλ Representational State Transfer (REST), το οποίο επιβάλει τον προσανατολισμό σε πόρους στην αρχιτεκτονική του Παγκόσμιου Ιστού, έλαβε σημαντική προσοχή από την κοινότητα των μηχανικών υπηρεσιών, καθώς στοχεύει στην αποδοτική γεφύρωση των συστημάτων επιχειρηματικού λογισμικού και του Παγκόσμιου Ιστού. Τα τελευταία χρόνια, στην περιοχή της Τεχνολογίας Λογισμικού λαμβάνει χώρα μια ανοιχτή δημόσια συζήτηση η οποία εστιάζει στους τρόπους ορθής εφαρμογής του REST τόσο σε ό,τι αφορά στην ανάπτυξη νέων επιχειρηματικών συστημάτων, όσο και στην προσαρμογή υφιστάμενων συστημάτων υπηρεσιών, έτσι ώστε οι πάροχοι υπηρεσιών να προσφέρουν τις δυνατότητες των υπηρεσιών τους μέσω επιπρόσθετων διεπαφών και συγκεκριμένα διεπαφών προσανατολισμένων σε πόρους. Επιπλέον, η συνύπαρξη υπηρεσιών ΠΣΔ και υπηρεσιών ΠΣΠ σε επιχειρηματικά περιβάλλοντα λογισμικού, εισάγει έναν αριθμό νέων προκλήσεων συναφών με την ανάπτυξη και την εξέλιξη υπηρεσιοστρεφών εφαρμογών που διαθέτουν διττές διεπαφές. Στην παρούσα διατριβή, μελετάμε δύο κύρια προβλήματα. Το πρώτο πρόβλημα αφορά σε ζητήματα και προκλήσεις που σχετίζονται με την προσαρμογή υπηρεσιών ΠΣΔ σε RESTful αρχιτεκτονικές. Για τον σκοπό αυτό, προτείνουμε μια διαδικασία κι ένα περιβάλλον-πλαίσιο το οποίο επιτρέπει την μοντελοποίηση, την ανάλυση και τον μετασχηματισμό διεπαφών ΠΣΔ έτσι ώστε να προσδιοριστούν αντίστοιχες διεπαφές ΠΣΠ. Το δεύτερο πρόβλημα αφορά στην ευθυγραμμία μεταξύ διεπαφών ΠΣΔ και διεπαφών ΠΣΠ. Πιο συγκεκριμένα, μελετάμε πως τα δύο υποδείγματα σχετίζονται εννοιολογικά και αρχιτεκτονικά και προτείνουμε μια μέθοδο κι ένα περιβάλλον-πλαίσιο για την εξέταση της υποκαταστασιμότητας μεταξύ υπηρεσιών που παρέχουν παρόμοια λειτουργικότητα αλλά εκτίθενται μέσω διαφορετικών σχεδιαστικών υποδειγμάτων διεπαφών. Η λύση σε αυτά τα προβλήματα είναι σημαντική καθώς, πρώτον, επιτρέπει την μεθοδολογική ανάλυση της σχέσης του προσανατολισμού σε διαδικασίες και του προσανατολισμού σε πόρους, δεύτερον, επιτρέπει τον σχεδιασμό και την υλοποίηση περιβαλλόντων-πλαισίων τα οποία μπορούν να χρησιμοποιηθούν για να παρέχουν δυνατότητες υπηρεσιών μέσω διττών διεπαφών και τρίτον, επιτρέπει τη συνεπή συνεξέλιξη υπηρεσιών διττών διεπαφών ως προς την οπτική του παρόχου υπηρεσιών και την επικύρωση της υποκαταστασιμότητας υπό την οπτική του καταναλωτή υπηρεσιών, όταν απαιτείται η εξέταση εναλλακτικών υπηρεσιών. Οι προσεγγίσεις και τα περιβάλλοντα-πλαίσια που προτείνονται αξιολογούνται μέσω μιας σειράς πειραμάτων και περιπτωσιολογικών μελετών. Τα αποτελέσματα αυτών δείχνουν ότι οι προτεινόμενες προσεγγίσεις είναι αποτελεσματικές, ότι μπορούν να χρησιμοποιηθούν για την ανάπτυξη προσαρμογέων υποδειγμάτων διεπαφών που λειτουργούν κατά το χρόνο εκτέλεσης κι ότι μπορούν να παρέχουν μια μέθοδο για την αποδοτική αποτίμηση της υποκαταστασιμότητας και της ευθυγραμμίας μεταξύ διιστάμενων, σχετικά με το ακολουθούμενο υπόδειγμα σχεδιασμού, διεπαφών υπηρεσιών

Discovering web services and JXTA peer-to-peer services in a unified manner

Abstract. Web services constitute the most prevailing instantiation of the service-oriented computing paradigm. Recently however, representatives of other computing technologies, such as peer-to-peer (p2p), have also adopted the service-oriented approach and expose functionality as services. Thus the service-oriented community could be greatly assisted, if these heterogeneous services were integrated and composed. A key towards achieving this integration is the establishment of a unified approach in service discovery. In this paper, we describe some features of a unified service query language and focus on its associated engine, which is used to discover web and p2p services in a unified manner. We exemplify how our unified approach is applied in the case of web and p2p service discovery in UDDI and JXTA, respectively. Additionally, we demonstrate how our service search engine is able to process heterogeneous service advertisements and thus to exploit the advertised syntactic, semantic, and quality-of-service properties during matchmaking.

Interoperability among heterogeneous services

Service-Oriented Computing (SOC) has been marked as the technology trend which caters for the interoperability among the components of a distributed system. However, the emergence of various incompatible instantiations of the SOC paradigm e.g. web, grid and p2p services, as well as the interoperability problems encountered within each of these instantiations (e.g. web service interoperability problems addressed by the WS-I Basic Profile) state clearly that interoperability is still elusive. In order to address this problem we first need to identify all problem dimensions and consequently to provide appropriate solutions. Within this paper we describe a set of interoperability dimensions that need to be considered and we present a generic service model which we view as a first step in addressing some of the identified problem dimensions

Cyclic animation of a human body using PDE surfaces

NoIn this work we propose a modelling technique for producing cyclic motions of human body. The surface of the human body has been created from a set of pre-configured curves that were used as the set of boundary conditions to solve a number of partial differential equations (PDE). These boundary curves are attached to a skeletal system that holds the animation for cyclic motions. An important function of the method described here is the use of mathematical expressions within Maya software for generating the cyclic motion leading to a very realistic movement. Thus, the user can interactively manipulate the position and movement of various body parts to achieve various cyclic motions. Finally the animation can be transferred to either the original mesh model from where the boundary curves associated with the PDE surface were extracted or to another mesh model with equivalent topology