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Visual Dynamic Model Inspecting with OPM Model-Based Simulation Environment. Yevgeny Yaroker, Valeria Perelman, Prof. Dov Dori 18 September 2014. Introduction. Our domain: Conceptual design phase in the systems engineering lifecycle. - PowerPoint PPT Presentation
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Visual Dynamic Model Inspecting with OPM Model-Based Simulation Environment
Yevgeny Yaroker,Valeria Perelman,Prof. Dov Dori
April 21, 2023
Introduction Our domain: Conceptual design phase in
the systems engineering lifecycle. The decisions made during this phase
are the most critical to get right and hardest to change.
Existing testing approaches operate on the system’s detailed design, a stage which is too technical for the customer to follow may be very expensive to backtrack
Motivation There is a need to detect problems starting at
early stages of the system development, when detailed design does not yet exist.
Benefits include: Debugging during earlier stages of system
development, finding system malfunctions before investing in extensive code writing
Working on a more abstract model – keeping the model simpler with concealed details.
Modeling with focus on satisfying requirements. Predictability of changes/modifications in design
Model-Based Simulation Frameworks System model simulation
frameworks for detailed design: Modelica, ARENA, Simulink, …
Graphical presentation of process flows OPM Animation (OPCAT)
Model-based simulation case tools: xUMLite – (xUML) …
run-time verification
unit tests integration tests
formal verification
questionnaires
Conceptual modeling
Time/Phase
checklistscenario
simulation
metrics
DetailedDesign
Sub-systemsImplementation
Integration
System testing and evaluation approaches
Non-formal
Formal
Conceiving & alternatives evaluation
prototyping
What makes the conceptual model evaluating so complicated?
Human abilities to comprehend system dynamics, based on numerous static diagrams, are limited even when well-organized and holistic modeling languages (ML) are used.
High level of abstraction, which is typical of conceptual MLs, propagate notations ambiguity.
These factors lead to numerous human errors while: constructing system models reading conceptual models written by others
Research Goal
Develop and evaluate a visual dynamic model inspecting with OPM model-based simulation environment.
What is Object Process Methodology (OPM)?
OPM is a comprehensive, generic systems development and lifecycle support paradigm
OPM Integrates the system’s function, structure and dynamics in a single, unifying model.
Complexity is controlled through recursive and selective scaling (zooming) of objects and/or processes to any desired level of detail.
The OPM model combines image and text: intuitive graphics a subset of natural English
OPM Basic Concepts
Object: A thing that exists or can exist physically or logically
Process: A thing that transforms an object by creating it or consuming it or changing its state
Objects and processes can be connected with links, which can be structural (such as aggregation, generalization) and procedural (enabling, transformation, and event links)
10
OPM main links
Structural Links Procedural linksConnect objects to objects Connect objects to processes
Aggregation-Participation
Generalization-Specialization
Exhibition-Characterization
Classification-Instantiation
Consumption
Result
Effect
Agent
Uni- and Bi-directionalTagged link
Instrument
object object
Solution Outline Develop a model-based animation mechanism
as an extension of OPM using the infrastructure provided by OPCAT
Define clear system behavioral rules in line with OPM syntax and semantics
Design a software tool with a wide user profile: having easy-to-use User Interface (UI), not requiring a special technical background providing efficient problem detection and reporting
mechanisms Develop a flexible system to enable future
extensions
Technical Requirements Simulation/visualization workflow requirements:
Simulation shall follow OPM rules. Instance-level simulation shall be enabled.
“DVD film” simulation mode requirement: Enable easy work through possible scenarios inexperienced users:
Forward/backward simulation, step by step/continuous simulation, pause/continue (relevant only for continuous mode), changing simulation speed
Debugging functional requirements: Capability to define breakpoints Provide “lifespan” component which graphically describes the state of all the
OPM entities at any stage of simulation Provide special “Debug Info” component which detects possible problems
and notifies user about them. Capability to reproduce problematic scenarios
Simulation Typical View
Process is colored if it is currently executed
Object with existing
instance is colored
Red token runs on the activated
link
Simulation Main Controls Main Toolbar – Controlling simulation flow
Starting/Stopping simulation. Playing forward/backward. Controlling simulation velocity. Invoking simulation properties dialog.
Status Bar – Observing simulation status Play mode. Current timeline.
Main toolbar
Status Bar
Model Debugging Process
User can toggle breakpoint on a process. The simulation runs till the breakpoint is
reached. Reaching the breakpoint will pause the
simulation.
Debug Information
Notifying a user regarding the problems making the further progress run impossible, such as: A process invocation failure, A required manual process activation, “No future simulation events” situation.
Architecture – Main Constructs
Task Queue consists of Simulation Tasks. A Simulation Task:
represents an atomic simulation activity implements Command and Undo DPs.
Task Queue keeps the simulation working schedule.
Rule defines the Simulation Tasks to be scheduled upon some simulation events.
Scheduler uses rules to build the Tasks Queue.
Architecture: The Three Layered Model
Tasks Queue Creation Layer
Tasks Queue Execution Layer
Plug-in Layer
Rules
Simulation Rule is defined for each OPM entity and for each simulation event. For instance, there is a rule for object’s
instance creation and its deletion. An activated rule determines the
Simulation Tasks to be executed and the set of next Rules to be scheduled.
For each rule there is a class implementing its functionality.
Process Activation Rule Example
Activation Conditions: The elements linked to the process with one of the
following links should be active - Instrument link. Condition link. …
Consequent Rules: Process termination will be scheduled t time units after its
activation time, where t – is the process execution time. Elements linked to the process with Consumption link will
be deactivated. …
Consequent Tasks: The process will be painted. Elements linked to the process with Result link will be
painted progressively. …
Evaluation Experiment
Group A Group B
SystemModel
1
Static (manual) analysis Analysis with the simulation environment assistance
SystemModel
2
Analysis with the simulation
environment assistance
Static (manual) analysis
Two OPM models were prepared for two different example systems.
The systems are very similar in their size and complexity. Structural and behavioral errors were inserted intentionally to
the OPM models. Two groups of students were asked to find all the errors in the
two models. Each group analyzed one system using solely static set of the
model diagrams, and another system using simulation tool. Following table describes the experiment setup
Evaluation Results (1) Group of 98 students made the experiments in
pairs (49 pairs). The experience of this group with OPM and
system modeling is average.
Behavioral errors found
(max = 5)
Structural errors found
(max = 5)
Static (manual)analysis
2.12 1.08
Analysis with theOPCAT simulation
environment
2.98 0.50
Evaluation Results (2)
The students were also asked to give their general impression about helpfulness of the tool. The average mark is 4.81 on a 1-7 scale.
T P
Behavioral aspect 5.66 < 0.001
Structural aspect -3.77 < 0.001
Paired t-test results. N =49 pairs, 98 students.
Summary
Through the research visual dynamic model inspecting with OPM model-based simulation environment was developed.
Results gathered using two experiments carried out on a large group of students confirmed the efficiency of the proposed solution.
Although the proposed solution is OPM-oriented, the architecture and attitude could be reused to implement simulation engines for other MLs