Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge Trace-Directed Modelling Status Update Timothy C. Lethbridge University of Ottawa

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge Progress so far The student who is to start will not start until January But –The student has a full scholarship, freeing up funds that I can use to put a second student on the project in January or Sept next year, or hire a student temporarily –I have a PhD student laying groundwork by studying how code can better be generated from state machines –I am continuing to develop plans

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge Research questions Q1: How to go from trace to model –Trace abstraction to generate a model Useful for understanding, simulation and generation of a system Q2: How to go from model to trace –Better tracing based on the model E.g. defining trace points

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge Q1: From trace to model What modeling formalisms should we use? –State machines Likely with a lage amount of concurrency Abstracting an entire trace or set of traces –Sequence diagrams (and similar) Not so useful for large cases o Not enough abstraction Good for scenarios, not as good for describing the entire behaviour of an element –Static diagrams (component/communication/class) Mapping states/threads to components

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge Converting a trace to a model Seek ‘similarities’ in sequences –Patterns, common hehavior that persists for a while, then becomes different Working hypothesis: Each is a state –Works with system traces, routine traces, etc. ‘Similarity function’ must be defined and van be varied Concurrency in traces gives rise to concurrent state machines –Synchronization between states might exist if multiple state transitions occur in different state machines at once

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge Varying the similarity function … Allows dynamically altering the –Number of states Function ‘everything equals everything’ returns a single state –Complexity of the diagram –Details of types of states visible in the model

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge What notation should be used? Use a textual UML format to allow programmatic manipulation We would like to use Umple –Many similarities to STATL, but broader applicability –Large subset of UML –Under our control –Code generation facilities Can run simulated system (executable model) to explore scenarios

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge What is the state of the art? Several papers in the literature, dating back to 2004 –So far I am unaware of any that translate traces to state machines for Large scale traces Highly concurrent trace models Tunable levels of abstraction

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge Q2: What can be added to a model to enable tracing? State boundaries –Transitions, synchronization,etc. –State machine abstraction level determines number of trace points Communication between components of various kinds Insert these into the system for the next iteration

Sept Tracing Status Update - Sept Montreal - Timothy Lethbridge Next steps Looking forward to studying real models to be provided by Mario Couture Also looking for suggestions for large traces to abstract into state machines Will work on literature review before state of the art