Rui Pais

Ecore representation for extending PNML for Input-Output Place-Transition nets

This paper presents a metamodel for the Input-Output Place-Transition nets (IOPT nets), a Petri net class targeted at controllers modeling. The proposed metamodel reuses many of the elements of the Petri Net Markup Language (PNML) metamodel, such as places, transitions, and arcs; it extends the PNML metamodel for Place/Transition nets to comprise concepts inherent to IOPT nets. The IOPT nets metamodel is described in Ecore format, putting IOPT nets in the puzzle of MDA artifacts taking benefit from the MDA infrastructure.

From UML state machines to Petri nets: History attribute translation strategies

This paper presents a set of translation strategies from state machines using the history attribute to a class of non-autonomous Petri nets named Input-Output Place Transition Nets (IOPT nets). IOPT nets extend the well-known low-level Petri net class of place transition nets with input and output signals and events. Other state machine elements translation mechanisms were already proposed and are here revised and improved to support the last available version of UML (UML 2.4 - Beta 2, March 2011). There are various goals that we intend to achieve with the translation from state machines to IOPT nets: benefit from the integration on a Petri net-based framework for the development of embedded systems using co-design techniques allowing generation of code for different platforms and languages; contribution for the development of tools to create, edit, verify proprieties, optimize, support model transformation, execute and visualize UML state machines.

Petri Net based Building Automation and Monitoring System

This paper presents a Petri net based building automation system and associated monitoring graphical user application. We adopt a model based development attitude, which means that we emphasize the use of models, and tools to handle those models. In this sense, system functionalities are captured as UML use cases, and Petri nets are used as the main modeling formalism. The systems model is built upon each use case and its translation into a state diagram or Petri net model. Afterwards, the set of partial models is combined through a composition operation, leading to the construction of a Petri net based behavioral model for the whole system. The proposal exploits the association between key characteristics of the Petri net model and key graphical characteristics presented in the systems synoptic. In this sense, execution of the Petri net model will produce an implicit update of the systems synoptic. The paper presents the application to a building monitoring system composed by three sub-systems: lighting, HVAC (heating, ventilation and air conditioning), and intrusion detection.

Towards Statecharts to Input-Output Place Transition Nets Transformations

This paper proposes a set of procedures addressing a Model Driven Architecture approach to translate of SysML statechart models into a class of non-autonomous Petri nets. The main goal of this set of procedures is to benefit from the model-based attitude allowing the integration of development flows based on statecharts with the ones based on Petri nets.

A tool for tailored code generation from Petri net models

The use of Petri nets for the modelling of discrete-event systems is well-studied. Yet, the tools allowing the implementation of these models, and supporting code generation, are still very few, almost non-existent. This paper starts by presenting a Petri net class, based on place/transition nets and well-known concepts from synchronised and interpreted Petri nets. This Petri net class allows the association of external input signals to transitions and the association of external output signals to transitions and place markings. Additionally, the class provides support for the specification of input and output events. Next, the paper presents a code generator able to output optimised executable code from these nets. The generated code can be optimised by several distinct strategies, which facilitate the creation of code tailored to specific platforms, as well as for specific classes of Petri nets

From SysML State Machines to Petri Nets Using ATL Transformations

The ATLAS Transformation Language (ATL) is a well-known hybrid model transformation language that allows both declarative and imperative constructs to be used in the definition of model transformations. In this paper, we present ATL transformations providing an integrated structural description of the source and target metamodels and the transformation between them. More specifically, the paper presents translation rules of Systems Modeling Language (SysML) state machines models into a class of non-autonomous Petri net models using ATL. The target formalism for the translation is the class of Input-Output Place Transition Nets (IOPT), which extends the well-known low-level Petri net class of Place/Transition Petri nets with input and output signals and events dependencies. Based on this Petri net class, a set of tools have been developed and integrated on a framework for the project of embedded systems using co-design techniques. The main goal is to benefit from the model-based attitude while allowing the integration of development flows based on SysML state machines with the ones based on Petri nets.

Two possible approaches for an intermediate GUI course

This poster presents the main pros and cons of two approaches for introducing intermediate students to the use of a complex class library in the context of Graphical User Interface programming. The approaches use different programming languages, integrated programming environments, and frameworks. The frameworks are used mainly for the development of application program interfaces for graphical user interfaces. These are useful in latter courses and are also important for student motivation.

Use of flash movies for teaching GUI programming

This paper proposes the use of Flash movies when introducing students to the use of a complex Integrated Development Environment in the context of a GUI programming course.

A versatile assignment in CS 2 (poster session): a file compression utility based on the Huffman code

With the advent of fast connectivity and cross-platform software, an older model of decoupled algorithm and visualizer can be discarded in favor of a model which permits a higher level of student interaction with the visualization. In this model, the student can stop and start the visualization, see a textual explanation of what the algorithm is doing, and be prompted to answer questions about the steps of the algorithm.