Einführung in XML

Das hier frei verfügbare Skript und die Sammlung an Klausuren mit Musterlösungen aus den Jahren 2006 bis 2015 geht auf die gleichnamige Vorlesung im Bachelorstudiengang Informatik an der Universität Kassel zurück, die von Prof. Dr. Wegner und ab 2012 von Dr. Schweinsberg angeboten wurde. Behandelt werden die Grundlagen der eXtensible Markup Language, die sich als Datenaustauschsprache etabliert hat. Im Gegensatz zu HTML erlaubt sie die semantische Anreicherung von Dokumenten. In der Vorlesung wird die Entwicklung von XML-basierten Sprachen sowie die Transformierung von XML-Dokumenten mittels Stylesheets (eXtensible Stylesheet Language XSL) behandelt. Ebenfalls werden die DOM-Schnittstelle (Document Object Model) und SAX (Simple API for XML) vorgestellt.

Grundlagen der Betriebssysteme

Das hier frei verfügbare Skript wurde zuletzt im Oktober 2003 in der 3. Auflage überarbeitet und war Grundlage der von Prof. Dr. Wegner bis dahin gehaltenen gleichnamigen Veranstaltung. Die Ursprünge gehen bis auf ein Skript des Kollegen Jürgen Nehmer (Kaiserslautern) aus den Siebzigern zurück. Eine wesentliche Überarbeitung erfuhr das Material mit Erscheinen des didaktisch exzellenten Buchs von Ben-Ari „Grundlagen der Parallel-Programmierung“ aus dem Jahr 1984. Konkrete Umsetzungen von Prozesssynchronisierungskonzepten in lauffähige Programme wurden allerdings ausgespart und finden sich im ebenfalls frei verfügbaren Skript „Interprozesskommunikation“.

Skript Interprozesskommunikation

Das hier frei verfügbare Skript gehört zu einer gleichnamigen Vorlesung, die von Prof. Dr. Lutz Wegner bis zum Sommersemester 2007 gehalten wurde. Davor lief sie bis 1999 unter dem etwas irreführenden Titel „Ausgewählte Themen zu Rechnernetzen“. Behandelt wird die IPC in UNIX-basierten Rechnernetzen. Dazu gehören allgemeine Kenntnisse der Prozessumgebung, die fork- und exec-Systemaufrufe, Lock Files, Signale, Pipes, das Botschaftenkonzept (message queues), Semaphore, Shared Memory, Remote Procedure Calls, Sockets und Threads. Jedes Konzept wird mit kleinen Beispielen besprochen, die in C geschrieben sind. Der Quelltext liegt auf unseren Anlagen vor (für AIX, LINUX, Solaris). Grundlage der Vorlesung und des Skripts ist das ausgezeichnete Buch von John Shapley Gray „Interprocess Communications in UNIX“ aus dem Jahr 1998 bzw. die auf Linux angepasste Auflage desselben Buches „Interprocess Communications in LINUX“ aus dem Jahr 2003.

Folien zur Vorlesung Sortierverfahren

Die hier frei verfügbare Foliensammlung stammt aus der gleichnamigen Master-Veranstaltung im Sommersemester 2014. Das zugehörige Skript (in Englisch) kann als PDF heruntergeladen werden von der Universität Turku (Lutz M. Wegner, Sorting – The Turku Lectures, Lecture Notes in Computing 2014, Univ. of Turku, Finland, http://tucs.fi/publications/attachment.php?fname=bWegner_LutzMx14a.full.pdf). Das überarbeitete Material geht auf eine dort im Jahre 1987 gehaltene Gastvorlesung zurück. Betrachtet werden Varianten von Quicksort und Heapsort, speziell bei Quicksort solche für Multimengen und Vorsortierung, sowohl für verkettete Listen als auch für Datenstrukturen mit Direktzugriff. Neben dem Standardheapsort werden die Floydverbesserung und Dijkstras Smoothsort vorgestellt. Eine Netzwerkvariante und zwei Externspeicherverfahren auf Basis von Quicksort und Heapsort werden untersucht. Der Stand der Technik bei den stabilen, in-situ Verfahren wird skizziert. Der Stoff eignet sich für eine Vorlesung mit angegliederten Projektübungen, in denen Studierende selbstständig Algorithmen, die als Pseudo-Code vorgegeben sind, in effizienten, lauffähigen Java-Code umsetzen und in einer Laufzeitbibliothek mit vorgegebenen Testdaten messen.

Programmierung in Pascal

Das hier frei verfügbare Skript gehört zu einer gleichnamigen Vorlesung, die von Prof. Dr. Lutz Wegner bis zum Wintersemester 1998/99 am damaligen Fachbereich 17 Mathematik/Informatik der Universität Kassel gehalten wurde. Thema ist die Einführung in die Programmierung, wie sie am Anfang fast aller Informatik-, Mathematik- und verwandter Ingenieurstudiengänge steht. Hier erfolgt die Einführung mit der Programmiersprache Pascal, die Niklaus Wirth (ehemals ETH Zürich) bereits 1968 entwickelte. Sie gilt als letzte Vertreterin der rein prozeduralen Sprachen und führt in der Regel zu sauber strukturierten Programmen. In der damals auf PCs weit verbreiteten Turbo Pascal Variante geht es auch um Objektorientierung, die charakteristisch für das heutige Programmierparadigma mit Java ist. Alte (und neu geschriebene) Pascal-Programme lassen sich problemlos mit den Free Pascal Open Source Compilern (www.freepascal.org) übersetzen und unter allen gängigen Betriebssystemen zur Ausführung bringen. Wer hierfür eine fachlich präzise und trotzdem vergleichsweise gut lesbare Einführung mit Hinweisen auf guten und schlechten Programmierstil braucht, wird hier fündig und kommt über den Stickwortindex am Ende auch schnell zu Einzelthemen wie Parameterübergabe oder das Arbeiten mit Pointern.

Interface issues in the ESCHER visual database editor

Presentation at the 1997 Dagstuhl Seminar "Evaluation of Multimedia Information Retrieval", Norbert Fuhr, Keith van Rijsbergen, Alan F. Smeaton (eds.), Dagstuhl Seminar Report 175, 14.04. - 18.04.97 (9716). - Abstract: This presentation will introduce ESCHER, a database editor which supports visualization in non-standard applications in engineering, science, tourism and the entertainment industry. It was originally based on the extended nested relational data model and is currently extended to include object-relational properties like inheritance, object types, integrity constraints and methods. It serves as a research platform into areas such as multimedia and visual information systems, QBE-like queries, computer-supported concurrent work (CSCW) and novel storage techniques. In its role as a Visual Information System, a database editor must support browsing and navigation. ESCHER provides this access to data by means of so called fingers. They generalize the cursor paradigm in graphical and text editors. On the graphical display, a finger is reflected by a colored area which corresponds to the object a finger is currently pointing at. In a table more than one finger may point to objects, one of which is the active finger and is used for navigating through the table. The talk will mostly concentrate on giving examples for this type of navigation and will discuss some of the architectural needs for fast object traversal and display. ESCHER is available as public domain software from our ftp site in Kassel. The portable C source can be easily compiled for any machine running UNIX and OSF/Motif, in particular our working environments IBM RS/6000 and Intel-based LINUX systems. A porting to Tcl/Tk is under way.

Managing Quality Properties of Web Service Compositions

Web services from different partners can be combined to applications that realize a more complex business goal. Such applications built as Web service compositions define how interactions between Web services take place in order to implement the business logic. Web service compositions not only have to provide the desired functionality but also have to comply with certain Quality of Service (QoS) levels. Maximizing the users' satisfaction, also reflected as Quality of Experience (QoE), is a primary goal to be achieved in a Service-Oriented Architecture (SOA). Unfortunately, in a dynamic environment like SOA unforeseen situations might appear like services not being available or not responding in the desired time frame. In such situations, appropriate actions need to be triggered in order to avoid the violation of QoS and QoE constraints. In this thesis, proper solutions are developed to manage Web services and Web service compositions with regard to QoS and QoE requirements. The Business Process Rules Language (BPRules) was developed to manage Web service compositions when undesired QoS or QoE values are detected. BPRules provides a rich set of management actions that may be triggered for controlling the service composition and for improving its quality behavior. Regarding the quality properties, BPRules allows to distinguish between the QoS values as they are promised by the service providers, QoE values that were assigned by end-users, the monitored QoS as measured by our BPR framework, and the predicted QoS and QoE values. BPRules facilitates the specification of certain user groups characterized by different context properties and allows triggering a personalized, context-aware service selection tailored for the specified user groups. In a service market where a multitude of services with the same functionality and different quality values are available, the right services need to be selected for realizing the service composition. We developed new and efficient heuristic algorithms that are applied to choose high quality services for the composition. BPRules offers the possibility to integrate multiple service selection algorithms. The selection algorithms are applicable also for non-linear objective functions and constraints. The BPR framework includes new approaches for context-aware service selection and quality property predictions. We consider the location information of users and services as context dimension for the prediction of response time and throughput. The BPR framework combines all new features and contributions to a comprehensive management solution. Furthermore, it facilitates flexible monitoring of QoS properties without having to modify the description of the service composition. We show how the different modules of the BPR framework work together in order to execute the management rules. We evaluate how our selection algorithms outperform a genetic algorithm from related research. The evaluation reveals how context data can be used for a personalized prediction of response time and throughput.

Why are There so Few Female Computer Scientists?

This report examines why women pursue careers in computer science and related fields far less frequently than men do. In 1990, only 13% of PhDs in computer science went to women, and only 7.8% of computer science professors were female. Causes include the different ways in which boys and girls are raised, the stereotypes of female engineers, subtle biases that females face, problems resulting from working in predominantly male environments, and sexual biases in language. A theme of the report is that women's underrepresentation is not primarily due to direct discrimination but to subconscious behavior that perpetuates the status quo.

Generative Temporal Planning with Complex Processes

Autonomous vehicles are increasingly being used in mission-critical applications, and robust methods are needed for controlling these inherently unreliable and complex systems. This thesis advocates the use of model-based programming, which allows mission designers to program autonomous missions at the level of a coach or wing commander. To support such a system, this thesis presents the Spock generative planner. To generate plans, Spock must be able to piece together vehicle commands and team tactics that have a complex behavior represented by concurrent processes. This is in contrast to traditional planners, whose operators represent simple atomic or durative actions. Spock represents operators using the RMPL language, which describes behaviors using parallel and sequential compositions of state and activity episodes. RMPL is useful for controlling mobile autonomous missions because it allows mission designers to quickly encode expressive activity models using object-oriented design methods and an intuitive set of activity combinators. Spock also is significant in that it uniformly represents operators and plan-space processes in terms of Temporal Plan Networks, which support temporal flexibility for robust plan execution. Finally, Spock is implemented as a forward progression optimal planner that walks monotonically forward through plan processes, closing any open conditions and resolving any conflicts. This thesis describes the Spock algorithm in detail, along with example problems and test results.

Learning Three-Dimensional Shape Models for Sketch Recognition

Artifacts made by humans, such as items of furniture and houses, exhibit an enormous amount of variability in shape. In this paper, we concentrate on models of the shapes of objects that are made up of fixed collections of sub-parts whose dimensions and spatial arrangement exhibit variation. Our goals are: to learn these models from data and to use them for recognition. Our emphasis is on learning and recognition from three-dimensional data, to test the basic shape-modeling methodology. In this paper we also demonstrate how to use models learned in three dimensions for recognition of two-dimensional sketches of objects.

Matching Interest Points Using Projective Invariant Concentric Circles

We present a new method to perform reliable matching between different images. This method exploits a projective invariant property between concentric circles and the corresponding projected ellipses to find complete region correspondences centered on interest points. The method matches interest points allowing for a full perspective transformation and exploiting all the available luminance information in the regions. Experiments have been conducted on many different data sets to compare our approach to SIFT local descriptors. The results show the new method offers increased robustness to partial visibility, object rotation in depth, and viewpoint angle change.

Validating Co-Training Models for Web Image Classification

Co-training is a semi-supervised learning method that is designed to take advantage of the redundancy that is present when the object to be identified has multiple descriptions. Co-training is known to work well when the multiple descriptions are conditional independent given the class of the object. The presence of multiple descriptions of objects in the form of text, images, audio and video in multimedia applications appears to provide redundancy in the form that may be suitable for co-training. In this paper, we investigate the suitability of utilizing text and image data from the Web for co-training. We perform measurements to find indications of conditional independence in the texts and images obtained from the Web. Our measurements suggest that conditional independence is likely to be present in the data. Our experiments, within a relevance feedback framework to test whether a method that exploits the conditional independence outperforms methods that do not, also indicate that better performance can indeed be obtained by designing algorithms that exploit this form of the redundancy when it is present.

Abstracting qualitative information for process supervision

Supervisory systems evolution makes the obtaining of significant information from processes more important in the way that the supervision systems' particular tasks are simplified. So, having signal treatment tools capable of obtaining elaborate information from the process data is important. In this paper, a tool that obtains qualitative data about the trends and oscillation of signals is presented. An application of this tool is presented as well. In this case, the tool, implemented in a computer-aided control systems design (CACSD) environment, is used in order to give to an expert system for fault detection in a laboratory plant

TU Graz: Course: 707.000 Web Science and Web Technology: Lecture 1

In this class, we will discuss the course organization and provide a basic motivation for and introduction to the course. Readings: Web science: a provocative invitation to computer science, B. Shneiderman, Communications of the ACM 50 25--27 (2007) [Web link] Readings: Chapter 1 & 2, A Framework for Web Science, T. Berners-Lee and W. Hall and J. A. Hendler and K. O'Hara and N. Shadbolt and D. J. Weitzner Foundations and Trends® in Web Science 1 (2006) [Web link] Originally from: http://kmi.tugraz.at/staff/markus/courses/SS2008/707.000_web-science/

Object Orientated PHP

To replace Application Scripting and Contemporary Programming Principles