masterarbeit: design of data model for description of timed … · 2012-10-11 · masterarbeit:...

Masterarbeit:Design of Data Model for Description of Timed

Automata and Algorithms for Their Retrieval in LogData

Yu Zhang

Technische Universität DresdenDepartment of Computer ScienceInstitut für Angewandte Informatik

April 17th, 2008

Yu Zhang (TUD) Masterarbeit April 17th, 2008 1 / 73

Outline

1 MotivationIntroductionTask Description

2 Design and ImplementationData ModelStorage of AutomataSearch Mechanism

3 Results and PerformanceTest CasesPerformance EvaluationPerformance Comparison

4 Conclusion and Future WorkConclusionFuture Work


Motivation Introduction

Outline







Timed Automata

Modern automation systems are mostly discrete events basedSystems can be described via hierarchical modelTimed automata can be used to describe such systemsTimed automaton: finite-state machine with clocks



Timed Automata



Motivation Task Description

Outline







My TasksPart of a Trace Analysis System for Failure Diagnosis

1.Design and develop a datamodel2.Mechanism to store automata3.Search mechanism that searches the known automata in trace

Search mechanism for small automataSearch mechanism for big automata

4. A trace generator



Part of Components in a Trace Analysis System


Design and Implementation Data Model

Outline







Design of the DatamodelConcept of the Datamodel

Generic, extensible and flexibleComposite Pattern used for purpose of complicated modelStrategy Pattern used for purpose of making analysis



Design the DatamodelUML of the Datamodel


Design and Implementation Storage of Automata

Outline







Problem of PersistenceObject/Relational Mapping (ORM)

Best solution to solve the problem of object persistenceAutomated and transparent persistence of objects in a Javaapplication to the tables in a relational database

An Object/Relational Mapping (ORM) Solution

API for performing basic CRUD(create, retrieve, update, delete)Language for specifying queriesFacility for specifying mapping metadataTechnique for the ORM implementation to interact withtransactional objects



Problem of PersistenceHibernate

A full object/relational mapping toolA solution to the problem of persistence data in JavaMediates the application’s interaction with a relational databaseAllows to develop persistent classes following object-orientedidiom



Problem of PersistenceSolving Persistence Problem with Hibernate

Developing ScenariosTop-down:start with existing domain model

Implement the domain model in JavaCreate mapping metadata for each persistent classConfigure Hibernate tool and start upStore and load objects

Bottom-up:start with an existing database schema and the domainmodel



Problem of PersistenceAn Example of Mapping Metadata



Problem of PersistenceEntity Relationship of the datamodel


Design and Implementation Search Mechanism

Outline







Trace and Trace Generator

Reads in a list of XML filesGenerates a random event trace including errors for each XML fileby calling a threadStarts all the threads in parallelWaits for each thread to finish



Search Mechanism

Takes a list of XML files and a trace as parametersSearch mechanism for small automata with less than four states

Search for the event sequenceSearch mechanism for big automata with more than four states

Search for the next transition



Search Mechanism for Small AutomataWork Flow



Search Mechanism for Big AutomataWork Flow



Search Mechanism for Big AutomataSupplement

Event corresponds a proper transition without Guard

Set current transition for further search

Event corresponds a proper transition with a Guard

Checks if the Guard is satisfiedIn case of satisfaction, set current transitionIn case of violation, reports time-out error


Results and Performance Test Cases

Outline







Performance Test Cases to Test the Functionality ofthe Search MechanismTest Cases for Search Mechanism of Small Automata

Various small automataSmall automata with cyclesSmall timed-automataHybrid small automata



Test Cases to Test the Functionality of the SearchMechanismTest Cases for Search Mechanism of Big Automata

Various big automataBig automata with cyclesBig timed-automata


Results and Performance Performance Evaluation

Outline






Results and Performance Performance Evaluation

Performance of the Two Search Mechanism


Results and Performance Performance Comparison

Outline






Results and Performance Performance Comparison

Search Time Comparison and Possible Reasons

Small: Compares the events in trace with the event sequenceAn automaton has several event sequences

Big:Compares the events in trace directly with the automaton


Conclusion and Future Work Conclusion

Outline






Conclusion and Future Work Conclusion

Conclusion

Datamodel:

An extensible mechanism to store and load timed automata in andfrom databaseAutomata analysis also included with analysis reslut savedAnalysis result dynamically added as automaton attribute

Search Mechanism:Searches known automata in a trace

Found automata and their information savedErrors during search also saved for purpose of diagnosis


Conclusion and Future Work Future Work

Outline







Future Work

Apply more powerful databases (e.g.Oracle) to support parallelstorage and loadApply type-safe annotations embedded directly in Java sourcecode when mapping metadata to avoid XML filesMapping before deploy to real worldOptimization of search mechanism for various user requirments

Search a great number of automata in parallel



End

Thanks for your attention and time for questions.


masterarbeit: design of data model for description of timed … · 2012-10-11 · masterarbeit:...

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