Drift time ion mobility spectrometry (DTIMS) is a rapid post ionization gas-phase separation technique that distinguishes between compounds based on their differences in reduced mass, charge and collisional cross-section while under a weak, time-invariant electric field. Standalone DTIMS is currently employed throughout the world for the detection of explosives, drugs and chemical-warfare agents. The coupling of IMS to MS (IM-MS) has enabled the performance of time-nested multidimensional separations with high sample throughput and enhanced peak capacity, allowing for the separation of ions not only based on their mass/charge (m/z) ratios, but also their shape. This allows for the elucidation of valuable structural information that can be utilized for determining gas phase ion conformation and differentiation between closely related ionic species. Over the past decade, these advances have transformed IM-MS applications and instrumental designs into one of the most rapidly growing areas of mass spectrometry. The work presented in this thesis is aimed at the development and subsequent characterization of a novel high-resolution resistive-glass atmospheric pressure DTIMS, and the application of this prototype DTIMS to the detection of environmentally relevant compounds. A review of the different types of ion mobility spectrometers, their principles of operation, and the advantages and disadvantages of each type are presented in Chapter 1. Chapter 2 describes the design and development of our prototype resistive glass DTIMS. A detailed description of the IMS hardware, including the ion sources, custom-built control computer, pulsing electronics, data acquisition system, and the timing schemes developed to operate the instrument in standalone DTIMS, multiplexed DTIMS, and IM-MS mode, are presented. Chapter 3 presents an initial characterization of the performance of a prototype resistive glass DTIMS under a wide range of instrumental parameters and also characterizes the radial ion distribution of the ions in the drift region of the spectrometer. Chapter 4 addresses the lack of sensitivity in DTIMS and explores ion trapping and multiplexing methods, introduces the principles of multiplexing and describes an extended multiplexing approach that encompasses arbitrary binary ion injection waveforms with variable duty cycles. Chapter 5 presents a detailed theoretical and experimental study of the separation power of our DTIMS and presents an evaluation of the field homogeneity and the performance of the ion gate.

Mitte der 90er Jahre wurde an der TU Chemnitz ein XML-Dialekt und die zugehörigen Transformationstools für Lehrmaterialien entwickelt, die in internetbasierten Fernkursen eingesetzt wurde. In der Folge wurden weitere Kursskripte auf der Basis dieses Dialekts erstellt. Diese Materialien sollten auch nach der Einführung von OLAT weitergenutzt werden können. Deshalb wurden das Transformationswerkzeug zum Tool xml2lms angepasst und um folgende Funktionalität erweitert: - Verpacken des übersetzten HTML-Skripts in das IMS-CP-Format, - Extraktion von "Folien" für Präsenzveranstaltungen aus der XML-Quelle, - Erstellen eines druckbaren Skripts im PDF-Format. Geplante Erweiterungen sind die Darstellung von mathematischen Formeln mit dem math.js-Paket und das Generieren von PDF-Folien mit Hilfe der LaTeX-Beamer-Klasse.

Maintenance, repair, and replacement of transmission mains and distribution system piping is expected to cost approximately $75 billion over the next two decades to ensure that public water systems are capable of providing the United States with safe drinking water. However, there is a significant gap between the funds available and the projected costs of infrastructure replacement or rehabilitation. Infrastructure Management Systems (IMS) have been developed to assist utilities and decision-makers in determining how to allocate resources for infrastructure. This project utilizes theTampa Water Department (TWD) as a case study to develop a tool for prioritizing infrastructure replacement. TWD is responsible for managing over 2,240 miles of pipeline. Building booms in the 1920s and 1950s have inadvertently resulted in a significant need to replace or rehabilitate pipelines due to the aging of the overall water supply infrastructure. To address this problem, TWD is taking the first steps in applying IMS to transmission anddistribution pipelines. Currently, approximately 500 miles of water mains have been slated for replacement or rehabilitation. The TWD has a GIS that has been used to map and integrate information on main breaks, service line breaks, customer complaints and modeled water age. Information on fire hydrant spacing and line flushing dates are also integrated into the GIS. Following development of the GIS based infrastructure replacement prioritization system, approximately 3,000 pipe segments were identified and queries were performed to help develop cost to benefit analyses. The results were used to develop a prioritized list of potential capital projects and incorporate the time value of money and event forecasting. The GIS was also used to develop indicators of the overall infrastructure condition. From this analysis it was possible to develop an approach to categorize projects and identify the resources needed to address high priority problems associated with undersized mains, unlined cast iron mains, asbestos cement mains, and hydraulic looping projects. As water infrastructure rehabilitation and replacement needs increase in the future, the need for adaptable methods to prioritize capital spending will also increase.This study has demonstrated the ability to prioritize long-term and short-term infrastructure projects using a GIS platform in conjunction with databases and spreadsheets.

Το έγγραφο είναι μια έρευνα του υποσυστήματος πολυμέσων διαδικτυακού πρωτοκόλλου και μια υλοποιήση ενός περιβάλλοντος προσομοίωσης, γνωστό ως testbed, που βασίζεται σε αυτό το πρωτόκολλο. Στην αρχή γίνεται μια εισαγωγή στην έννοια του IMS. Στο δεύτερο κεφάλαιο, περιγράφουμε τη γενική αρχιτεκτονική του IMS. Στο τρίτο κεφάλαιο, υπάρχει αναφορά στο επίπεδο σηματοδοσίας και όλα τα στοιχεία του. Στο τέταρτο κεφάλαιο περιγράφουμε τις υπηρεσίες που παρέχει το IMS και την αρχιτεκτονική του Open IMS Core που αποτελεί το περιβάλλον προσομοίωσής μας. Τέλος, αναλύουμε τα βήματα με σκοπό να εγκαταστήσουμε τον Open IMS Core ρησιμοποιώντας το λειτουργικό σύστημα Linux. / The script is a research of the Internet Protocol Multimedia Subsystem (IMS) and an implementation of a simulation environment, known as testbed and based on this protocol. In the beginning, there is an introduction to the meaning of IMS.In chapter two, we describe the general architecture of IMS. In chapter three, there is a reference to the signalling level and all of its elements. In chapter four we describe the services that IMS provides and the architecture of the Open IMS Core which is our simulation environment. Finally, we analyse the steps in order to install Open Ims Core using Linux operating system.

Το αντικείμενο αυτής της διπλωματικής εργασίας είναι η μελέτη της δομής υπηρεσιών πάνω στα 0ίκτυα Επόμενης Γενιάς (Next Generation Networks, NGN). Συγκεκριμένα, περιγράφεται η αρχιτεκτονική IMS (IP Multimedia Subsystem) πάνω στην οποία βασίζεται η δομή των 0ικτύων Επόμενης Γενιάς. Στα πλαίσια της παρούσας διπλωματικής εργασίας γίνεται αρχικά μια σύντομη αναφορά στο ιστορικό δημιουργίας του IMS, ενώ στην συνέχεια γίνεται μια εκτεταμένη περιγραφή του μοντέλου και του τρόπου λειτουργίας του IMS. Συγκεκριμένα, αναλύονται οι οντότητες και τα σημεία αναφοράς από τα οποία αποτελείται το IMS καθώς και τα πρωτόκολλα που χρησιμοποιεί. Στη συνέχεια γίνεται μία αναφορά στην ασφάλεια του IMS, όπου αναφέρονται πιθανοί κίνδυνοι και απειλές για το IMS καθώς και τρόποι αντιμετώπισής τους. Έπειτα, παρουσιάζονται και περιγράφονται αναλυτικά οι υπηρεσίες που μπορεί να προσφέρει το IMS στα πλαίσια των 0ικτύων Επόμενης Γενιάς. Τέλος, γίνεται παρουσίαση ενός παραδείγματος εφαρμογής της υπηρεσίας VoIP πάνω από την IMS αρχιτεκτονική. Για την υλοποίηση αυτού του παραδείγματος χρησιμοποιήθηκε το πρόγραμμα προσομοίωσης OPNET 10.0, ενώ συλλέχθηκαν αποτελέσματα σχετικά με τη συμπεριφορά του πρωτοκόλλου SIP και της υπηρεσίας VoIP σε IMS περιβάλλον. / The objective of this diploma thesis is the study of the service structure of Next Generation Networks (NGN). Especially, the IMS architecture (IP Multimedia Subsystem) is being described, which the NGN structure is based on. Initially, there is a quick reference to the history of the development of IMS, and continually an extensive description is being made about the model and the functional mode of IMS. Next, security aspects of IMS are being described, and continually there is a presentation about the services that IMS offers. Finally, an example is being presented regarding the application of VoIP service using the IMS architecture. For the configuration of this example, the simulation program OPNET 10.0 was used, while results were collected regarding the behavior of SIP protocol and VoIP service in the IMS environment.

Στην εργασία αυτή μελετήθηκε το μελλοντικό δίκυο 4G UMTS με ΙΡ διασύνδεση στο δίκτυο πυρήνα. Επίσης μελετώ τα νέα πρωτόκολλα για mobile internet IPV4, IPV6 καθώς επίσης και την πολυμεσική δομή ΙΜS. / In this Maste thesis, study the 4G UMTS network with IP conection in the core network. So i analyze the new protocolls for mobile internet IPV4, IPV6 and the multimedia structure IMS

Η παρούσα διπλωματική εργασία είναι η υλοποίηση σε λογισμικό του Home Subscriber Server (HSS). Ο HSS είναι ένας εξυπηρετητής ζωτικής σημασίας για το IP Multimedia Subsystem (IMS). Αποτελεί την κύρια βάση του δικτύου που περιέχει σημαντικές πληροφορίες για τους χρήστες και επιτελεί, μαζί με κάποιες άλλες οντότητες,την πιστοποίηση και την εξουσιοδότηση των χρηστών, που επιθυμούν να χρησιμοποιήσουν το IMS δίκτυο. / This thesis is the software implementetion of a Home Subscriber Server (HSS). The HSS is a server vital for IP Multimedia Subsystem (IMS). It is the main basis of the network which contains important information for users and it performs, along with some other entities, certification and authorization of users who wish to use the IMS network.

Conformance testing is the process of checking that a system possesses a set of desired properties and behaves in accordance with some predefined requirements. In this context, passive testing techniques are used when the system under test cannot be interrupted or access to the system's interfaces is unavailable. Passive testing relies on the observation of the implementation during runtime, and the comparison of the observation with the expected behavior, defined through conformance properties. The objective of this thesis is to define a novel methodology to validate communicating protocols by passive testing. Existing approaches are derived from works with finite-state and labelled transition specifications and as such, they presume there exists a causality relation between the events observed in the implementation (the trace). When dealing with message-based protocols, such as the Session Initiation Protocol (fundamental for IMS services), such causality does not necessarily exist and furthermore, it may only be determined through data parts. Since existing techniques are optimized for dealing with control parts, they present limitations for testing based on data parts: reduced expressibility and succinctness of conformance properties, as well as problems to deal with satisfaction of properties including future conditions. In this work we present a message-based/data-centric approach for dealing with these issues. Observations in a trace are in the form of messages. Expected behavior is defined in a bottom-up fashion, starting from expected criteria that must be fulfilled by one or more messages, defined as constraints between the message data fields. Temporal relations by quantification over the criteria, e.g. a property may require that certain criteria "must be held for all messages in the trace". Our approach allows to express formulas about the future and past of the trace, allowing to define more general criteria than through control parts alone. Issues related to satisfaction of properties and declaration of conformance verdicts are also discussed here. Although observation of a behavior defined as a property is indication of conformance, lack of observation is not necessarily indicative of a fault. Several solutions to this issue have been proposed and implemented in this work. Finally, our work presents interesting perspectives, in terms of extensibility for online detection or improved expressiveness, but also since a message-based approach provides an alternative view to traditional testing techniques

Sustaining the safety and operability of civil infrastructure assets, including buildings, is a complex undertaking that requires a perpetual cycle involving inspection, and further decisions for renewal fund allocation. However, inspection, which is the basis for all subsequent decisions, is a complex task to manage, particularly when a large number of assets are involved. The current lack of a structured process with visual referencing as well as the high subjectivity and inflexibility to changing inspection requirements make current inspections very costly and time consuming. This research improves the building inspection process by introducing a 3D system for inspection management that has four unique features: (1) a structured assessment approach that considers multiple organizations, buildings and inspectors, using a GIS interface; (2) a 3D visual referencing method for marking problem areas during inspections to facilitate all on-site inspections, thus reducing time and cost; (3) a visual guidance module to reduce inspection subjectivity; and (4) a flexible module for designing different assessment types. The proposed inspection management system creates 3D building plans from 2D Computer-Aided Drawing (CAD) to provide location referencing that enhances inspection effectiveness. The visual guidance system allows inspectors with various experience levels to perform consistent inspections and requires less training, thus reducing costs. Flexible inspection generation also allows a variety of inspection types, such as condition and level of service, to be readily incorporated. A computerized prototype system has been developed using the Windows Presentation Foundation’s XAML markup language with underlying C# programming on a tablet computer for experimentation. The thesis provides a detailed description of system development and reports the benefits of the system on a sample inspection. Accordingly, the system has proven most useful for large organizations that own a large number of building assets that require frequent inspections.

Master of Engineering (Research) / Educational standards are having a significant impact on e-Learning. They allow for better exchange of information among different organizations and institutions. They simplify reusing and repurposing learning materials. They give teachers the possibility of personalizing them according to the student’s background and learning speed. Thanks to these standards, off-the-shelf content can be adapted to a particular student cohort’s context and learning needs. The same course content can be presented in different languages. Overall, all the parties involved in the learning-teaching process (students, teachers and institutions) can benefit from these standards and so online education can be improved. To materialize the benefits of standards, learning resources should be structured according to these standards. Unfortunately, there is the problem that a large number of existing e-Learning materials lack the intrinsic logical structure required, and further, when they have the structure, they are not encoded as required. These problems make it virtually impossible to share these materials. This thesis addresses the following research question: How to make the best use of existing open learning resources available on the Internet by taking advantage of educational standards and specifications and thus improving content reusability?In order to answer this question, I combine different technologies, techniques and standards that make the sharing of publicly available learning resources possible in innovative ways. I developed and implemented a three-stage tool to tackle the above problem. By applying information extraction techniques and open e-Learning standards to legacy learning resources the tool has proven to improve content reusability. In so doing, it contributes to the understanding of how these technologies can be used in real scenarios and shows how online education can benefit from them. In particular, three main components were created which enable the conversion process from unstructured educational content into a standard compliant form in a systematic and automatic way. An increasing number of repositories with educational resources are available, including Wikiversity and the Massachusetts Institute of Technology OpenCourseware. Wikivesity is an open repository containing over 6,000 learning resources in several disciplines and for all age groups [1]. I used the OpenCourseWare repository to evaluate the effectiveness of my software components and ideas. The results show that it is possible to create standard compliant learning objects from the publicly available web pages, improving their searchability, interoperability and reusability.