1 © B.J. Krämer • FHH • Jan 2001

Distributed Software Engineering

(DatenVerabeitungsTechnik, DVT)

Distributed Software Engineering

(DatenVerabeitungsTechnik, DVT)

Bernd J. KrämerFernUniversität, Hagen

February 2002

Bernd J. KrämerFernUniversität, Hagen

February 2002

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 © B.J. Krämer • FHH • Jan 2001

Major Research Areas

• Distributed Systems Management and Modeling• E-Learning techniques, tools & environments• Dependable Software Engineering

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Distributed Systems Management & Modeling

• Automated Correlation of Event Messages (DFG)• Enhanced distributed object interfaces (EU, 4th

FP, ...)• Formal modeling and analysis techniques

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• 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 © 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

We need to extract & document this knowledge explicitly & in computerized a form

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 © 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 Editorhttp://www.fernuni-hagen.de/DVT

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 © B.J. Krämer • FHH • Jan 2001

HTML-Based CoursewareGlossary[Text]

Definition[Text]

Example[Text]

Example[Graphics]

Detailed Explica[Text]

Glossary[Text]

Definition[Text]

Example[Text]Example

[Graphics]

Detailed Explication[Text]

DEEPENS

DEEPENS

ILLUSTRATES

ILLUSTRATES

EXPLAINS

•Component Type

•Material Type

•Rhetoric Relationships

[Mann, Thomson: Rhet-

orical Structure Theory,

TR, ISI, 1987]

11 © B.J. Krämer • FHH • Jan 2001

Evaluation

ContentStructurePresentation

lumped together in HTML! links second class entities, embedded in material

white-box designno composition at architecture levelno global link maintenance possible

authors supported at “programming level” only HTML editing client- & server-side scripting (Javascript, PHP, Perl, ...)

Sharing & Reuse impeded

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

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Dependable Software Engineering

• HOL-based Verification framework for PLC programs

14 © B.J. Krämer • FHH • Jan 2001

Thank You!