1. 1© B.J. Krämer FHH Jan 2001 Distributed Software Engineering (DatenVerabeitungsTechnik, DVT) Distributed Software Engineering (DatenVerabeitungsTechnik, DVT) Bernd J. Krämer FernUniversität, Hagen February 2002 Bernd J. Krämer FernUniversität, Hagen February 2002

2. 2© B.J. Krämer FHH Jan 2001 Department in Brief People –9 scientific staff –3 technical staff, secretary –a few student collabortors Teaching –foundations of CS –programming –software engineering –multimedia technology Research –some basic research –mainly applied research

3. 3© B.J. Krämer FHH Jan 2001 Major Research Areas Distributed Systems Management and Modeling E-Learning techniques, tools & environments Dependable Software Engineering

4. 4© B.J. Krämer FHH Jan 2001 Distributed Systems Management & Modeling Automated Correlation of Event Messages (DFG) Enhanced distributed object interfaces (EU, 4th FP,...) Formal modeling and analysis techniques

5. 5© B.J. Krämer FHH Jan 2001 Network services may depend on: –OS resources (memory, devices, sockets, semaphores,...) –Communication services (TCP, IP, UDP,...) –Configuration files –... Heterogeneity aggravates coherent documentation of dependencies Openness prohibits static description Research Objective: Computerized descriptions of service dependencies to automate fault management Documenting Dependencies

6. 6© B.J. Krämer FHH Jan 2001 Approach Part of these dependencies can be derived automatically through analysis –Network topology through ICMP echo packets –Services on a host, e.g., through nmap –Parameters of services through analysis of config files –Analysis of System Information Repositories and installation scripts But –A couple of significant dependencies rely on peculiarities of the actual network –Knowledge is only maintained intangeably in the brain of experienced system administrators KWe need to extract & document this knowledge explicitly & in computerized a form

7. 7© B.J. Krämer FHH Jan 2001 Approach (cont´d) Define common & open logfile format for different services Mine these standardized data for: –Dependencies between services, shared sub-services & resources –Root cause of a failure through: event correlation using log files monitoring modifications of configuration file & comparison with log file events...

8. 8© B.J. Krämer FHH Jan 2001 E-Learning Techniques & Tools Personalized Curriculum Builder (CUBER, 5th FP) http://www.cuber.net Online Test & Exercise Environment (Multibook, BMBF) http://www.multibook.de Electronic Multimedia Components Catalog (EuropeMMM, EU, 4th FP) https://mmk.fernuni-hagen.de, www.campussource.de Component-oriented Authoring & Learning Environment (UVM) MultiMedia Instruction in Safe and Secure Systems (MMISS, BMBF) http://www.mmiss.de Learner tools, e.g., dynamically extensible Diagram Editor http://www.fernuni-hagen.de/DVT

9. 9© B.J. Krämer FHH Jan 2001 Online Learning requires Platform incl. tools for management & administration of courses, learning events, classes,... [VU platforms: http://www.campussource.org (GPL, Apr 2001)] Content Learner support –cognitive tools –adaptive tools –tutoring Methods & tools supporting learning application development

10. 10© B.J. Krämer FHH Jan 2001 HTML-Based Courseware Glossary [Text] Definition [Text] Example [Text] Example [Graphics] Detailed Explica [Text] Glossary [Text] Definition [Text] Example [Text] Example [Graphics] Detailed Explication [Text] DEEPENS ILLUSTRATES EXPLAINS Component Type Material Type Rhetoric Relationships [Mann, Thomson: Rhet- orical Structure Theory, TR, ISI, 1987]

11. 11© B.J. Krämer FHH Jan 2001 Evaluation éContent éStructure éPresentation  lumped together in HTML!  links second class entities, embedded in material êwhite-box design êno composition at architecture level éno global link maintenance possible  authors supported at “programming level” only éHTML editing éclient- & server-side scripting (Javascript, PHP, Perl,...)  Sharing & Reuse impeded

12. 12© B.J. Krämer FHH Jan 2001 Software Engineering vs. Hypermedia Application Engineering Conceptual modeling –description/visualization of existing parts of the world –modeling of domain of discourse (topic maps, concept graphs, educational modeling) Specification –functional & non-functional requirements –content, presentation layout, activity Design & Implementation –architecture, component (services & data), user interface –architecture, component (serv., mm material), navigation, presentation (space, time, linking), user interface –Tools –CASE, PMM tools –commerc. programming level tools, R&D prototyes

13. 13© B.J. Krämer FHH Jan 2001 Dependable Software Engineering HOL-based Verification framework for PLC programs

14. 14© B.J. Krämer FHH Jan 2001 Thank You!