The research is conducted in the area of software methodologies with the emphasis on the integration of legacy systems with the client/server environment. The investigation starts with identifying the characteristics of legacy systems in order to determine the features and technical characteristics required of an integration methodology. A number of existing methodologies are evaluated with respect to their features and technical characteristics in order to derive a synthesis for a generic methodology. This evaluation yields the meta primitives of a generic methodology. The revised spiral model (Boehm,1986; DuPlessis & Vander Wah,1992) is customised to arrive at a software process model which provides a framework for the integration of legacy systems with the client/server environment. The integration methodology is based on this process model. / Computing / M. Sc. (Information Systems)

Publisering av webbplatser sker traditionellt i ett centraliserat nätverk där en webbserver distribuerar webbplatsens filer till sina klienter. Detta gör det möjligt för större företag eller regeringar att välja vilket innehåll som ska visas och tar bort den frihet som World Wide Web ursprungligen medförde. Att använda ett decentraliserat nätverk som värd för webbplatser kan dock vara fördelaktigt i vissa situationer på grund av de decentraliserade nätverkens höga skalbarhet och skydd mot censur. Denna studie syftar till att fastställa hur en webbplats kan publiceras i ett decentraliserat nätverk och om det kan vara att föredra för vissa typer av webbplatser. Studien syftar också till att ta reda på om det finns några säkerhetsbrister i de decentraliserade nätverken. Detta gjordes genom en litteraturstudie och genom att skapa ett test-system som kan stresstesta en webbplats som ligger på en vanlig webbserver och de decentraliserade lösningarna IPFS och Hypercore. Studien har visat att decentraliserade nätverk i allmänhet distribuerar en webbplats till många klienter snabbare i de flesta situationer. Vidare visas också att det finns några problem för en decentraliserad webbplats som inte finns i en webbplats som ligger på en vanlig webbserver. Bland dessa problem finns det vissa etiska diskussioner att ta hänsyn till när det gäller behandling av personuppgifter, oönskad spridning av olagligt innehåll och möjligheten att radera publicerat innehåll. I studien drogs slutsatsen att om en viss webbplats och dess ägare kan överblicka nackdelarna med ett decentraliserat nätverk bör det med största sannolikhet föredras framför en traditionell webbserver. / Hosting websites is traditionally done in a centralized network where a web server distributes the website’s files to it’s clients. This enables larger companies or governments to choose what content is shown and remove the freedom that the world wide web initially brought. However, using a decentralized network to host websites might be favorable in some situations due to the decentralized networks’ high scalability and protection against censorship. This study aims to determine how a website can be published in a decentralized network and if it can be preferred for some types of websites. The study also aims to find out if there exist any security vulnerabilities in the decentralized networks. This was done by a literature study and by creating a benchmarking system that can stress-test a website hosted on a traditional web server and the decentralized solutions IPFS and Hypercore. The study has shown that decentralized networks generally distribute a website to many clients faster in most situations. Further, it is also shown that there exists a few problems for a decentralized website that is not present in a website hosted on a traditional web server. Among these problems, there are some ethical discussions to be considered regarding the processing of personal data, unwanted distribution of illegal content, and the possibility of deleting published content. The study concluded that if a given website and its owner can oversee the disadvantages of a decentralized network, it should most likely be preferred over a traditional web server

Natural language understanding has been a persistent challenge to researchers in various computer science fields, in a number of applications ranging from user support systems to entertainment and online teaching. A long term goal of the Artificial Intelligence field is to implement mechanisms that enable computers to emulate human dialogue. The recently developed ALICEbots, virtual agents with underlying AIML scripts, by A.L.I.C.E. foundation, use AIML scripts - a subset of XML - as the underlying pattern database for question answering. Their goal is to enable pattern-based, stimulus-response knowledge content to be served, received and processed over the Web, or offline, in the manner similar to HTML and XML. In this thesis, we describe a system that converts the AIML scripts to Prolog clauses and reuses them as part of a knowledge processor. The inference mechanism developed in this thesis is able to successfully match the input pattern with our clauses database even if words are missing. We also emulate the pattern deduction algorithm of the original logic deduction mechanism. Our rules, compatible with Semantic Web standards, bring structure to the meaningful content of Web pages and support interactive content retrieval using natural language.

Implantation and the care of vascular reconstructions and accesses for haemodialysis is one of areas of cardiovascular surgery. Both vascular reconstructions, known as bypasses, and prosthetic haemodialytic accesses, known as grafts, are used only if conventional therapies are unsuccessful. Thus effectivity of these operations is critically important for patient survival. The aim of this thesis is development of software system for evidence data obtained during vascular operations and following checkups. Important is also support for basic analytical and statistical processing of collected data. Another goal is to transform collected data into knowledge useful for increasing effectivity of vascular operations.

The Java Devlopment Environment defines SQLJ as a standard way of embedding the relational database language SQL in the object-oriented programming language Java. Oracle Corporation provides an extension of SQLJ that supports dynamic SQL constructs for the processing of SQL commands that are not completely known at compile time. Unfortunately, these constructs are not sufficient to handle all dynamic situations, so that the programmer has to depend on other SQL embeddings, such as JDBC, in addition to Oracle's SQLJ. In this thesis we implement several extensions to Oracle's SQLJ so that all dynamic situations can be programmed in SQLJ, without resorting to other SQL embeddings. We also add a sub-query based for loop facility, similar to the one provided in Oracle's database programming language PL/SQL, as an improvement over the iterator constructs that SQLJ provides. This thesis discusses the design, development and implementation of these SQLJ extensions, and provided applications that show the utility of these extensions in terms of clarity and power. / by Louis M. Bradley. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Este trabalho apresenta uma ferramenta de apoio ao desenvolvimento de aplicações distribuídas, baseadas em RPCs, para o ambiente Windows 95. Discute, ainda, algumas aplicações construídas para validar o sistema, as quais seguem o paradigma cliente-servidor. É feita uma revisão bibliográfica dos assuntos mais relevantes relacionados ao tema e apresentados os detalhes de implementação da ferramenta. Esta foi implementada com técnicas de orientação a objetos, sendo composta por um Gerador Automático de Stubs e uma Biblioteca RPC, além de possibilitar a utilização de um Serviço de Binding. As aplicações construídas procuram explorar as potencialidades da ferramenta, sendo fornecidas também orientações gerais para o desenvolvimento de aplicações distribuídas no ambiente Windows 95. / This work presents a tool to support the development of RPC-based distributed applications in the Windows 95 environment. It also discusses some applications built to validate the system, which follow the client-server model. A theoretical review of the most relevant topics related to the field is done and the tool’s implementation details are presented. This tool was implemented with object-oriented techniques and comprises an automatic Stub Generator and an RPC Library, together with a Binding Service. The distributed applications that were built try to explore the tool’s full potential. General guidelines regarding the development of distributed applications for the Windows 95 environment are also provided.

Hypergoemetric Series are very important in mathematics and come up regularly when dealing with the precise definitions of constants such as <i>e</i>, &pi; and Apery's constant &sigmaf;(3). The evaluation of such series to high precision is traditionally done with multiple divisions, multiplications and factorials, which all takes a long time to compute, especially when the computation is done on a single machine. The interest lies in performing this computation in parallel and in a distributed fashion. In this thesis, we present a simple distributed toolkit for doing such computations by splitting the problem into smaller sub-problems, solving these sub-problems in parallel on distributed machines and then combining the result at the end. Our toolkit takes care of all the networking for the user; connectivity, dropped connections, management of the Clients and the Server. All the user has to provide is the definition of the problem; how to split the problem into sub-problems, how to solve the sub-problems and finally how to combine the sub-problems and produce a result. The toolkit records timings for computation as well as for communication. What is different about our application is that all the code is written in Java (which is completely machine independent) and all the Clients are Java Applets. This means that having a web browser in enough to take part in the computation when it is distributed over the internet. We are almost guaranteed that every computer on the internet has a web browser. The Java Plug-in (if unavailable) can easily be downloaded from Sun's web site. We present a comparison between Java's native BigInteger library and an FFT based Integer Library written by R. Howell of University of Kansas. This study is important since we are doing computations with very large integers. To test our system, we evaluate <i>e</i> to different number of digits of precision and show that our system truly works and is easy for anyone to use.

Hypergoemetric Series are very important in mathematics and come up regularly when dealing with the precise definitions of constants such as <i>e</i>, &pi; and Apery's constant &sigmaf;(3). The evaluation of such series to high precision is traditionally done with multiple divisions, multiplications and factorials, which all takes a long time to compute, especially when the computation is done on a single machine. The interest lies in performing this computation in parallel and in a distributed fashion. In this thesis, we present a simple distributed toolkit for doing such computations by splitting the problem into smaller sub-problems, solving these sub-problems in parallel on distributed machines and then combining the result at the end. Our toolkit takes care of all the networking for the user; connectivity, dropped connections, management of the Clients and the Server. All the user has to provide is the definition of the problem; how to split the problem into sub-problems, how to solve the sub-problems and finally how to combine the sub-problems and produce a result. The toolkit records timings for computation as well as for communication. What is different about our application is that all the code is written in Java (which is completely machine independent) and all the Clients are Java Applets. This means that having a web browser in enough to take part in the computation when it is distributed over the internet. We are almost guaranteed that every computer on the internet has a web browser. The Java Plug-in (if unavailable) can easily be downloaded from Sun's web site. We present a comparison between Java's native BigInteger library and an FFT based Integer Library written by R. Howell of University of Kansas. This study is important since we are doing computations with very large integers. To test our system, we evaluate <i>e</i> to different number of digits of precision and show that our system truly works and is easy for anyone to use.

We consider a class of queueing systems that consist of server pools in parallel and multiple customer classes. Customer service times are assumed to be exponentially distributed. We study the asymptotic behavior of these queueing systems in a heavy traffic regime that is known as the Halfin and Whitt many-server asymptotic regime. Our main contribution is a general framework for establishing state space collapse results in the Halfin and Whitt many-server asymptotic regime for parallel server systems having multiple customer classes. In our work, state space collapse refers to a decrease in the dimension of the processes tracking the number of customers in each class waiting for service and the number of customers in each class being served by various server pools. We define and introduce a state space collapse function, which governs the exact details of the state space collapse. Our methodology is similar in spirit to that in Bramson (1998); however, Bramson studies an asymptotic regime in which the number of servers is fixed and Bramson does not require a state space collapse function. We illustrate the applications of our results in three different parallel server systems. The first system is a distributed parallel server system under the minimum-expected-delay faster-server-first (MED-FSF) or minimumexpected- delay load-balancing (MED-LB) policies. We prove that the MED-FSF policy minimizes the stationary distribution of total number of customers in the system. However, under the MED-FSF policy all the servers in our distributed system except those with the lowest service rate experience 100% utilization but under the MED-LB policy, on the other hand, the utilizations of all the server pools are equal. The second system we consider is known as the N-model. We show that when the service times only depend on the server pool providing service a static priority rule is asymptotically optimal. Finally, we study two results conjectured in the literature for V-systems. We show for all of these systems that the conditions on the hydrodynamic limits can easily be checked using the standard tools that have been developed in the literature to analyze fluid models.

Τα τελευταία χρόνια η ανάπτυξη των Ανοιχτών Συστημάτων Υπερκειμένου (ΑΣΥ) είναι ευρεία με την προσθήκη νέων πεδίων και αρχιτεκτονικών που βοηθούν στην καλύτερη οργάνωση της πληροφορίας με στόχο την εξομοίωση και επαύξηση της σκέψης του ανθρώπου στο συγκεκριμένο τομέα. Ωστόσο, η χρησιμοποίηση των ΑΣΥ από το ευρύ κοινό είναι πολύ μικρή διότι η κατηγορία των συστημάτων αυτών δεν έχει καταφέρει μέχρι στιγμής να γίνει γνωστή για τα πλεονεκτήματα που προσφέρει όσον αφορά τη διαχείριση, τη δόμηση και τη σύνδεση της πληροφορίας. Επίσης, η κοινωνία των ΑΣΥ δεν έχει ακόμα παγιώσει κοινές μεθοδολογίες και υποδομές που θα βοηθούσαν κάθε developer να εισάγει εύκολα στην εφαρμογή του λειτουργίες υπερκειμένου. Στην παρούσα Μεταπτυχιακή εργασία γίνεται μια προσπάθεια για την ανάπτυξη μιας υποδομής που βοηθά τον developer στην εύκολη ενσωμάτωση υπηρεσιών υπερκειμένου στην εφαρμογή του. Έτσι, μελετήθηκε, σχεδιάστηκε και υλοποιήθηκε ο τρόπος με τον οποίο μπορεί να γίνει ανακάλυψη υπηρεσιών (service discovery) στα σύγχρονα Ανοικτά Συστήματα Υπερκειμένου βασισμένα σε Ψηφίδες (ΑΣΥ-ΒΨ). Στα πλαίσια της αρχιτεκτονικής της ανακάλυψης υπηρεσιών των ΑΣΥ-ΒΨ μελετήθηκαν οι αρχιτεκτονικές πελάτη/εξυπηρετητή και peer-to-peer. Το άμεσο αποτέλεσμα της συγκεκριμένης προσπάθειας είναι η παροχή στον developer εργαλείου (μηχανισμού) που τον βοηθάει στην αναζήτηση και επισκόπηση υπηρεσιών υπερκειμένου και στην εύκολη επιλογή κατάλληλης υπηρεσίας (με βάση τα χαρακτηριστικά της). Το μελλοντικό αποτέλεσμα της συγκεκριμένης προσπάθειας θα είναι η επίτευξη της γνωστοποίησης των υπηρεσιών που προσφέρουν τα ΑΣΥ-ΒΨ σε όλο και μεγαλύτερο σύνολο από developers με αποτέλεσμα όλο και περισσότερες εφαρμογές να χρησιμοποιούν τις υπηρεσίες των ΑΣΥ-ΒΨ. / In the last few years, Component-Based Open Hypermedia Systems (CB-OHS) have been widely developed with the addition of new hypermedia domains and architectural models for better data organization with main aim to equate and increase the human thinking in this particular field. However, OHS aren’t widely used because they haven’t managed, until this time, to become popular for the advantages that they offer on management, structuring and data linking. Additionally, the OHS community hasn’t yet effectively targeted in the establishment of common methodologies and frameworks that could help any developer to insert hypermedia functionality into his applications. In this Master’s thesis an effort is being made to develop an infrastructure which will help any developer to integrate easily, in his application, hypermedia services. Taking into consideration the above issues, the application of Service Discovery functionality to Component-Based Open Hypermedia Systems was investigated, analyzed and developed, in the context of this project. Trying to specify the architecture that should better fit in this case, two different types of architecture were examined; the client/server and the peer-to-peer architecture. The direct objective of this study is to provide developers with a tool that will help them to search easily and effectively, review and finally choose the proper structure service for them based on each service’s characteristics. A long-term objective of the current research is to make CB-OHS services widely known to developer communities in order to broaden the utilization of the above mentioned services by more and more applications.