Minimalist Architecture to Generate Embedded System Web User Interfaces

Part 9: Embedded Systems and Petri NetsInternational audienceThis paper presents a new architecture to semi-automatically generate Web user interfaces for Embedded Systems designed using IOPT Petri Net models. The user interfaces can be used to remotely control, monitor and debug embedded systems using a standard Web Browser. The proposed architecture takes advantage of the distributed nature of the Internet to store all static user interface data and software on third-party Web services (the Cloud), and execute the user-interface code on the user’s Web Browser. A simplified protocol is proposed to enable remote control, status-monitoring, debugging and step-by-step execution, minimizing resource consumption on the physical embedded devices, including processing load, memory and communication bandwidth. As the user interface data and code are kept on third-party Web services, these resources can be shared among multiple embedded device units, and the hardware requirements to implement the devices can be simplified, leading to reduced cost solutions. To prevent down-time due to network problems or server failures, a fault-tolerant topology is suggested. The distributed architecture is transparent to end-users, observing just a Web interface for an embedded device on the other side of an Internet URL

The DS-Pnet modeling formalism for cyber-physical system development

This work presents the DS-Pnet modeling formalism (Dataflow, Signals and Petri nets), designed for the development of cyber-physical systems, combining the characteristics of Petri nets and dataflows to support the modeling of mixed systems containing both reactive parts and data processing operations. Inheriting the features of the parent IOPT Petri net class, including an external interface composed of input and output signals and events, the addition of dataflow operations brings enhanced modeling capabilities to specify mathematical data transformations and graphically express the dependencies between signals. Data-centric systems, that do not require reactive controllers, are designed using pure dataflow models. Component based model composition enables reusing existing components, create libraries of previously tested components and hierarchically decompose complex systems into smaller sub-systems. A precise execution semantics was defined, considering the relationship between dataflow and Petri net nodes, providing an abstraction to define the interface between reactive controllers and input and output signals, including analog sensors and actuators. The new formalism is supported by the IOPT-Flow Web based tool framework, offering tools to design and edit models, simulate model execution on the Web browser, plus model-checking and software/hardware automatic code generation tools to implement controllers running on embedded devices (C,VHDL and JavaScript). A new communication protocol was created to permit the automatic implementation of distributed cyber-physical systems composed of networks of remote components communicating over the Internet. The editor tool connects directly to remote embedded devices running DS-Pnet models and may import remote components into new models, contributing to simplify the creation of distributed cyber-physical applications, where the communication between distributed components is specified just by drawing arcs. Several application examples were designed to validate the proposed formalism and the associated framework, ranging from hardware solutions, industrial applications to distributed software applications

NOVA mobility assistive system: Developed and remotely controlled with IOPT-tools

UID/EEA/00066/2020In this paper, a Mobility Assistive System (NOVA-MAS) and a model-driven development approach are proposed to support the acquisition and analysis of data, infrastructures control, and dissemination of information along public roads. A literature review showed that the work related to mobility assistance of pedestrians in wheelchairs has a gap in ensuring their safety on road. The problem is that pedestrians in wheelchairs and scooters often do not enjoy adequate and safe lanes for their circulation on public roads, having to travel sometimes side by side with vehicles and cars moving at high speed. With NOVA-MAS, city infrastructures can obtain information regarding the environment and provide it to their users/vehicles, increasing road safety in an inclusive way, contributing to the decrease of the accidents of pedestrians in wheelchairs. NOVA-MAS not only supports information dissemination, but also data acquisition from sensors and infrastructures control, such as traffic light signs. For that, it proposed a development approach that supports the acquisition of data from the environment and its control while using a tool framework, named IOPT-Tools (Input-Output Place-Transition Tools). IOPT-Tools support controllers’ specification, validation, and implementation, with remote operation capabilities. The infrastructures’ controllers are specified through IOPT Petri net models, which are then simulated using computational tools and verified using state-space-based model-checking tools. In addition, an automatic code generator tool generates the C code, which supports the controllers’ implementation, avoiding manual codification errors. A set of prototypes were developed and tested to validate and conclude on the feasibility of the proposals.publishersversionpublishe

Petri net based development of globally-asynchronous locally-synchronous distributed embedded systems

Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de ComputadoresA model-based development approach (MBDA) for Globally-Asynchronous Locally- Synchronous (GALS) Distributed Embedded Systems (DESs) is proposed. This approach relies on the GALS-DESs specification through (low- or high-level) Petri net classes, which ensure that the created models are GALS, locally deterministic, distributable, networkindependent, and platform-independent and support their simulation, verification, and implementation (using simulation, model-checking, and code generation tools). The use of network- and platform-independent models enable the use of heterogeneous communication networks to support the distributed components interaction and enable the use of heterogeneous platforms to support the components and the communication nodes implementation. To enable the proposed MBDA, Petri nets are extended with a set of the concepts, most notably time-domains and asynchronous-channels. Algorithms to support the verification of GALS-DES models and their decomposition into implementable sub-models are also proposed. A tool chain framework (IOPT-tools) was extended with this work proposals, supporting their validation and the GALS-DESs development.Fundação para a Ciência e a Tecnologia - grant ref. SFRH/BD/62171/200

Developing Globally-Asynchronous Locally- Synchronous Systems through the IOPT-Flow Framework

Throughout the years, synchronous circuits have increased in size and com-plexity, consequently, distributing a global clock signal has become a laborious task. Globally-Asynchronous Locally-Synchronous (GALS) systems emerge as a possible solution; however, these new systems require new tools. The DS-Pnet language formalism and the IOPT-Flow framework aim to support and accelerate the development of cyber-physical systems. To do so it offers a tool chain that comprises a graphical editor, a simulator and code gener-ation tools capable of generating C, JavaScript and VHDL code. However, DS-Pnets and IOPT-Flow are not yet tuned to handle GALS systems, allowing for partial specification, but not a complete one. This dissertation proposes extensions to the DS-Pnet language and the IOPT-Flow framework in order to allow development of GALS systems. Addi-tionally, some asynchronous components were created, these form interfaces that allow synchronous blocks within a GALS system to communicate with each other

Executable models for Embedded Controllers Development -A Cloud Based Development Framework

Abstract-We present IOPT-Tools, a tool framework for the development of digital controllers based on graphical executable models. The framework supports edition, simulation, verification through state-space querying, and code generation for several hardware platforms, most notably microcontrollers (e.g. Arduino, PIC, and Raspberry Pi) and FPGAs. The tool framework uses a class of Petri nets and is cloud based: the development process is performed using a browser

Refining IOPT Petri Nets Class for Embedded System Controller Modeling

Since its inception, the Input-Output Place-Transition (IOPT) class of Petri nets have changed in response to the gained experience in the use of its associated tools freely available as a cloud based toolset. Here, we informally present the current state of the IOPT net class as supported by the IOPT-Tools, publicly available at http://gres.uninova.pt/IOPT-Tools/. The corresponding formal syntax and semantics are presented, followed by an illustrative example. Finally, we give a brief presentation of the respective XML-based interchange format and conclude

Geração automática de sistemas compatíveis com o Arrowhead Framework utilizando IOPT-Tools

Nesta dissertação propõe-se uma extensão às ferramentas IOPT-Tools por forma a supor-tarem a geração sistemas compatíveis com o Arrowhead Framework. Os sistemas gerados têm a capacidade de se registar (como fornecedores) ou procurar (enquanto consumidores) serviços no Arrowhead Framework. O Arrowhead Framework conta com um conjunto de ferramentas que permitem, o registo, a pesquisa e a orquestração de sistemas produtores e/ou consumidores de serviços, para que possam interagir dinamicamente, sem ser necessário que se conheçam previa-mente. O uso de IOPT-Tools permite tirar proveito das suas capacidades de edição e validação de modelos, bem como da geração automática de código. Neste trabalho foi necessário instalar e realizar um estudo sobre as várias ferramentas do Arrowhead Framework e das IOPT-Tools, identificar alterações/extensões a efetuar às IOPT-Tools e desenvolver uma biblioteca em C capaz de suportar a interação dos sistemas com o Ar-rowhead Framework. A validação das alterações/extensões às IOPT-Tools, bem como da biblio-teca desenvolvida foram feitas através da geração e execução de um conjunto de sistemas com-patíveis com o Arrowhead Framework.In this dissertation it is proposed an extension to the IOPT-Tools tools in order to support the generation of systems compatible with the Arrowhead Framework. The generated systems have the ability to register (as providers) or search (as consumers) for services in the Arrowhead Framework. Arrowhead framework has a set of tools that allow the registration, research and orchestration of producer and/or service consumer systems, so that they can interact dynamically, without having to know each other beforehand. The use of IOPT-Tools allows you to take ad-vantage of your model editing and validation capabilities as well as automatic code generation. In this work it was necessary to install and perform a study on the various tools of the Arrowhead Framework and IOPT-Tools, to identify changes/extensions to be made at IOPT-Tools and develop a C library capable of supporting the interaction of the systems with the Ar-rowhead Framework. The validation of the changes/extensions to IOPT-Tools as well as the de-veloped library were done through the generation and execution of a set of systems compatible with the Arrowhead framework