Implementing OCL Invariants with Constrained Data Types, Alexander Paar. The Object Constraint Language (OCL) facilitates textual specifications of constraints that apply to Unified Modeling Language (UML) models. In particular, OCL is used for the specification of invariants in UML class diagrams. This paper compares the implementation of OCL invariants in program code by means of aspect-oriented programming (AOP) on the one hand and by means of value space constrained data types on the other hand. By contradistinction of these two approaches it will be argued that the availability of constraint-based type derivation and value space-based subtyping in a statically typed programming language can provide for the enforcement of OCL invariants already at compile time as opposed to runtime. PDF
Zhi# - OWL Aware Compilation, Alexander Paar and Denny Vrandečić. The usefulness of the Web Ontology Language to describe domains of discourse and to facilitate automatic reasoning services has been widely acknowledged. However, the programmability of ontological knowledge bases is severely impaired by the different conceptual bases of statically typed object-oriented programming languages such as Java and C# and ontology languages such as the Web Ontology Language (OWL). In this work, a novel programming language is presented that integrates OWL and XSD data types with C#. The Zhi# programming language is the first solution of its kind to make XSD data types and OWL class descriptions first-class citizens of a widely-used programming language. The Zhi# programming language eases the development of Semantic Web applications and facilitates the use and reuse of knowledge in form of ontologies. The presented approach was successfully validated to reduce the number of possible runtime errors compared to the use of XML and OWL APIs. Download PDF BibTeX
Searching and Using External Types in an Extensible Software Development Environment", Alexander Paar. Schema and ontology languages have proved to be useful for conceptualizing knowledge in a variety of applications. In many software projects, XML Schema Definition data types and ontological concept descriptions coexist with programming language class hierarchies. However, only programming language type definitions are fully integrated into today's software development environments. Support for external type systems is spotty. For programmers, it is particularly tedious to search type definitions in XML schema files and OWL ontologies, to browse external type hierarchies, to investigate external type members, and to analyze and comprehend the use of external type definitions in program code. In this work, it will be argued that improved search capabilities are required to ease the use of schema and ontology languages in software projects. Difficulties of searching type definitions in software project workspaces will be indicated. An extensible compiler framework will be outlined that facilitates the use of schema and ontology languages in C# programs. An Eclipse-based integrated development environment will be described that makes XML data types and OWL concept descriptions first-class citizens of the source code editor. Finally, identical search and (just in time) program analysis features for programming language and external type definitions will be suggested. BibTeX
2009, Computers in the Human Interaction Loop, Human-Computer Interaction Series, Springer Verlag, ch. "Ontological Modeling and Reasoning", Alexander Paar, Jürgen Reuter. BibTeX
2009, Applied Intelligence, "A Formally Specified Ontology Management API as a Registry for Ubiquitous Computing Systems", Alexander Paar, Jürgen Reuter, John Soldatos (Athens Information Technology), Kostas Stamatis (Athens Information Technology), and Lazaros Polymenakos (Athens Information Technology). BibTeX
2003, ACM Personal and Ubiquitous Computing Journal, "The BTRC Bluetooth Remote Control System", Fridtjof Feldbusch, Alexander Paar, Manuel Odendahl, and Ivan Ivanov. BibTeX
2012, 1st Symposium on Languages, Applications and Technologies (SLATE 2012), Braga, Portugal, "From Program Execution to Automatic Reasoning - Integrating Ontologies into Programming Languages" (Keynote), Alexander Paar. PDF BibTeX
2011, South African Institute of Computer Scientists and Information Technologists Conference on Knowledge, Innovation and Leadership in a Diverse, Multidisciplinary Environment (SAICSIT 2011), Cape Town, South Africa, "Static typing with value space-based subtyping", Alexander Paar and Stefan Gruner. BibTeX
2011, South African Institute of Computer Scientists and Information Technologists Conference on Knowledge, Innovation and Leadership in a Diverse, Multidisciplinary Environment (SAICSIT 2011), Cape Town, South Africa, "A domain-specific language for URDAD based requirements elicitation", Fritz Solms, Craig Edwards, Alexander Paar, and Stefan Gruner. BibTeX
2011, 8th Extended Semantic Web Conference (ESWC 2011), Heraklion, Greece, "Zhi# - OWL Aware Compilation", Alexander Paar and Denny Vrandečić. PDF BibTeX
2006, 21st IEEE/ACM International Conference on Automated Software Engineering (ASE 2006), Tokyo, Japan, "Programming Language Inherent Support for Constrained XML Schema Definition Data Types and OWL DL", Alexander Paar and Walter F. Tichy. BibTeX
2006, 3rd IFIP Conference on Artificial Intelligence Applications & Innovations (AIAI 2006), Athens, Greece, "A Formally Specified Ontology Management API as a Registry for Ubiquitous Computing Systems", Alexander Paar, Jürgen Reuter, John Soldatos (Athens Information Technology), Kostas Stamatis (Athens Information Technology), and Lazaros Polymenakos (Athens Information Technology). BibTeX
2005, 2nd International Conference on Embedded Software and Systems (ICESS 2005), Xi'an, P.R. China, "An Ontology-based Framework for Dynamic Resource Management in Ubiquitous Computing Environments", Ippokratis Pandis (Carnegie Mellon University), John Soldatos (Athens Information Technology), Alexander Paar, Jürgen Reuter, Michael Carras (Athens Information Technology), and Lazaros Polymenakos (Athens Information Technology). BibTeX
2005, 9th IASTED International Conference on Software Engineering and Applications (SEA 2005), Phoenix, AZ, USA, "Zhi#: Programming Language Inherent Support for XML Schema Definition", Alexander Paar and Walter F. Tichy. BibTeX
2003, 18th Annual ACM SIGPLAN Conference on Object Oriented Programming Systems, Languages And Applications (OOPSLA 2003), Anaheim, CA, USA, "Semantic Software Engineering Tools", Alexander Paar. BibTeX
2002, 8th Euro-Par, Paderborn, Germany, "A Novel Predication Scheme for a SIMD System-On-Chip", Alexander Paar, Manuel L. Anido (Federal University of Rio de Janeiro), and Nader Bagherzadeh (University of California, Irvine). BibTeX
2002, 16th International Conference on Architecture of Computing Systems (ARCS 2002), Karlsruhe, Germany, "A Bluetooth Remote Control System", Fridtjof Feldbusch, Alexander Paar, Manuel Odendahl, and Ivan Ivanov. BibTeX
2010, 2nd International Workshop on Search-driven development: Users, Infrastructure, Tools and Evaluation (SUITE 2010), Cape Town, South Africa, "Searching and Using External Types in an Extensible Software Development Environment", Alexander Paar. BibTeX
2007, 4th International Workshop on Software Language Engineering (ateM 2007), Nashville, TN, USA, "Zhi# - Programming Language Inherent Support for Ontologies", Alexander Paar. BibTeX
2005, 1st Australasian Ontology Workshop (AOW 2005), Sydney, Australia, "A Pluggable Architectural Model and a Formally Specified Programming Language Independent API for an Ontological Knowledge Base Server", Alexander Paar, Jürgen Reuter, and Jaron Schaeffer. BibTeX
2003, 1st Workshop on Embedded Systems for Real-Time Multimedia (ESTIMedia 2003), Newport Beach, CA, USA, "A Component Oriented Simulator for HW/SW Co-Designs", Alexander Paar, Haitao Du (University of California, Irvine), and Nader Bagherzadeh (University of California, Irvine). BibTeX
2003, 5th Autonomic Computing Workshop - Active Middleware Services (AMS 2003), Seattle, WA, USA, "Semantic Software Engineering Approaches for Automatic Service Lookup and Integration", Alexander Paar and Walter F. Tichy. BibTeX
2002, 15th Brazilian Symposium on Integrated Circuit Design (SBCCI 2002), Porto Alegre, Brazil, "A Novel Method for Improving the Operation Autonomy of SIMD Processing Elements", Manuel L. Anido (Federal University of Rio de Janeiro), Alexander Paar, and Nader Bagherzadeh (University of California, Irvine). BibTeX
2002, 5th Euromicro Symposium on Digital System Design (DSD 2002), Dortmund, Germany, "Improving the Operation Autonomy of SIMD Processing Elements by Using Guarded Instructions and Pseudo Branches", Manuel L. Anido (Federal University of Rio de Janeiro), Alexander Paar, and Nader Bagherzadeh (University of California, Irvine). BibTeX
2003, Technical Report (Universität Karlsruhe, Fakultät für Informatik, ISSN 1432-7864), "Grundlagen des Autonomen Rechnens (Interner Bericht 2003-14)", Alexander Paar, Gábor Szeder, Tom Gelhausen, and Marc Schanne (Hrsg.). BibTeX
2010, Dissertation, Universität Karlsruhe (TH), Germany, "Zhi# - Programming Language Inherent Support for Ontologies". BibTeX
2002, Diplomarbeit, Universität Karlsruhe (TH), Germany, "A Novel Predication Scheme for a SIMD System-On-Chip developed with a Component Oriented Simulator". BibTeX
2002, Studienarbeit, Universität Karlsruhe (TH), Germany, "Design and Implementation of a Bluetooth Based Ubiquitous Remote Control System". BibTeX
2001, IEEE Computer Society International Design Competition (IEEE CSIDC), Washington, DC, USA, "The Universal BTRC Remote Control System", Alexander Paar, Manuel Odendahl, Ivan Ivanov, and Fridtjof Feldbusch.
2012, Symposium on Languages, Applications and Technologies, Braga, Portugal, "From Program Execution to Automatic Reasoning - Integrating Ontologies into Programming Languages", Alexander Paar. PDF BibTeX
2012, WeST Spring Mindswap, St. Goar, Germany, "Position Statement", Alexander Paar. PDF BibTeX
2010, Zuse Collatz Colloquium, University of Pretoria, South Africa, "Konrad Zuse - Der Erfinder des Computers", Alexander Paar. PDF
2010, Research Workshop of the University of Pretoria Computer Science Department, Diep in die Berg, South Africa, "Zhi# - Programming Language Inherent Support for Ontologies", Alexander Paar.
2006, Advanced Developers Conference, Frankenthal, Germany, "Design Patterns with C# - An Introduction to Design Patterns for Object Oriented Systems", Alexander Paar.
2005, .NET Developers Group Stuttgart, Germany, "Object Oriented Software Design Patterns: Beyond the Gang of Four", Alexander Paar.
2004, .NET Developers Group Stuttgart, Germany, "XML: Elements, Attributes, Namespaces, and... Constraints!", Alexander Paar.
2013, International Conference on Ambient Systems, Networks and Technologies (ANT 2013), Halifax, Nova Scotia, Canada.
2013, International Conference on Cloud Computing and Services Science (CLOSER 2013), Aachen, Germany.
2012, Workshop on Programming the Semantic Web (PSW 2012), Boston, USA.
2012, International Conference on Ambient Systems, Networks and Technologies (ANT 2012), Niagara Falls, Ontario, Canada.
2012, Symposium on Languages, Applications and Technologies (SLATE 2012), Braga, Portugal.
2012, International Workshop on Web APIs and Services Mashups (Mashups 2012), Bertinoro, Italy.
2012, International Conference on Cloud Computing and Services Science (CLOSER 2012), Porto, Portugal.
2011, National Conference on XML and its Applications (XATA 2011), Vila do Conde, Portugal. Editorial Advisory Board of the book "Innovations in XML Applications and Metadata Management: Advancing Technologies".
2011, International Workshop on Web APIs and Services Mashups (Mashups 2011), Lugano, Switzerland.
2011, International Conference on Cloud Computing and Services Science (CLOSER 2011), Noordwijkerhout, The Netherlands.
2010, International Workshop on Web APIs and Services Mashups (Mashups 2010), Ayia Napa, Cyprus.
2010, International Conference on Cloud Computing and Services Science (CLOSER 2010), Valencia, Spain.
2010, Workshop on Transforming and Weaving Ontologies in Model Driven Engineering (TWOMDE 2010), Malaga, Spain.
2010, International Workshop on Modeling and Visualization of XML and Semantic Web Data (MoViX 2010), Bilbao, Spain.
2010, International Workshop on Benchmarking of XML and Semantic Web Applications (BenchmarX 2010), Tsukuba, Japan.
2009, Workshop on Transforming and Weaving Ontologies in Model Driven Engineering (TWOMDE 2009), Toulouse, France.
2009, International Workshop on Schema Languages for XML (X-Schemas 2009), Riga, Latvia.
2009, International Workshop on Modeling and Visualization of XML and Semantic Web Data (MoViX 2009), Linz, Austria.
2009, International Workshop on Benchmarking of XML and Semantic Web Applications (BenchmarX 2009), Brisbane, Australia.
2008, Workshop on Transforming and Weaving Ontologies in Model Driven Engineering (TWOMDE 2008), Toulouse, France.
2006, Workshop on Meta-modeling and Ontologies (WoMM 2006), Karlsruhe, Germany.
... slows the rate of scientific progress.
Please form your own opinion on David Lorge Parnas' article in the Communications of the ACM (November 2007/Vol. 50, No. 11).
... the workshops gone? Asks Moshe Y. Vardi in his editor's letter in the Communications of the ACM (January 2011/Vol. 54, No. 1).
My complete bibliography can be found here.
My DBLP computer science bibliography can be found here.
My Google Scholar profile can be found here.
My CiteULike profile can be found here.