Aniko Costa
Universidade Nova de Lisboa, Faculdade De Ciências e Tecnologia, Faculty Member
Research Interests:
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This paper addresses the use of events within discrete-event systems modeling formalisms, presenting the concept of event life time when enclosed in the detection of a specific behavior defined by sequences of events. This concept defines... more
This paper addresses the use of events within discrete-event systems modeling formalisms, presenting the concept of event life time when enclosed in the detection of a specific behavior defined by sequences of events. This concept defines the time interval during which a macro-event is valid (a macro-event is an event computed as the result of a pre-defined sequence of events). Two types of life times are defined: Absolute and Relative. Absolute life time is associated with the maximum time between the occurrence of the first and last event in the sequence. The relative life time is associated with each elementary event from the sequence and is defined by minimum and maximum values among which the next event in the sequence must occur. If the next event does not occur during the defined time, the event expires. Finally the use of these concepts is discussed presenting some specific cases of use.
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ABSTRACT In this paper, a set of event types for human-system interaction modeling is presented, and its usage with IOPT nets (Input-Output Place-Transition Petri nets) models is illustrated. Currently, a non-autonomous event based on the... more
ABSTRACT In this paper, a set of event types for human-system interaction modeling is presented, and its usage with IOPT nets (Input-Output Place-Transition Petri nets) models is illustrated. Currently, a non-autonomous event based on the computation of the change with respect to a specific threshold of input signals values on two consecutive execution steps is defined for IOPT models. Other types of events are proposed, allowing the definition of an event not only based on a threshold in the signal value, but also as a change on the variation of the signal. The concept of delayed events considers two values in different time steps (other than consecutive steps). This concept can be applied to previous types of events. The concept of composed events is also introduced, in order to create events dependent on two or more events on the same signal, at the same time step as well as at different time steps. Finally, an example is used to illustrate the concepts presented.
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ABSTRACT A model-based development flow based on IOPT Petri nets models and its insertion in a digital system design course is presented. The IOPT-Tools framework is used to support a cloud enabled design automation flow, including... more
ABSTRACT A model-based development flow based on IOPT Petri nets models and its insertion in a digital system design course is presented. The IOPT-Tools framework is used to support a cloud enabled design automation flow, including specification of system's behavior, state space based verification, and automatic code generation (C and VHDL) leading to implementation deployment into reconfigurable computing platforms. Teaching flow method is presented, supported by reconfigurable platforms (FPGA based boards and Arduino devices) giving adequate flexibility for exercising different implementation strategies and allowing laboratory prototyping during classes. The proposed approach was fully validated during a course on Digital Systems Design offered to Electric and Computer Engineering MSc course, and student's assessment on usage of cloud based development IOPT-Tools framework is analyzed.
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In this paper, an ultrasonic anemometer based in the time of flight is presented. The wind speed and direction is obtained using four ultrasonic transducers in an orthogonal configuration. Two transducers are used in each orthogonal... more
In this paper, an ultrasonic anemometer based in the time of flight is presented. The wind speed and direction is obtained using four ultrasonic transducers in an orthogonal configuration. Two transducers are used in each orthogonal direction as transmitter and receiver of a short sequence of pulses and the time of flight is recorded in both ways. The system is based on a low-cost Arduino-Nano board and the overall system was tested in a wind tunnel, where accuracy and linearity were analyzed. The developed anemometer is intended to be used in a scale model sailboat to support its autonomous navigation.
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The paper presents a novel design methodology of cyber-physical systems supported by computer aided tools. In particular, IOPT and Hippo tools are involved in the design and analysis techniques of the system. The proposed idea combines... more
The paper presents a novel design methodology of cyber-physical systems supported by computer aided tools. In particular, IOPT and Hippo tools are involved in the design and analysis techniques of the system. The proposed idea combines the main advantages of both tools by offering the complex design path of the control part of the cyber-physical system, including specification, analysis and verification, decomposition, and modelling stages. Additionally, the designer is able to choose the most suitable representation of the system (graphical or formal). The presented concepts are illustrated by a case-study example.
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Ferreira, Ricardo and Gomes, Luís and Costa, Anikó (2010) Interligação intrae inter-circuito de componentes especificados com Redes de Petri. [Paper]. In: REC'2010 – VI Jornadas sobre Sistemas Reconfiguráveis, 4-5 Fevereiro... more
Ferreira, Ricardo and Gomes, Luís and Costa, Anikó (2010) Interligação intrae inter-circuito de componentes especificados com Redes de Petri. [Paper]. In: REC'2010 – VI Jornadas sobre Sistemas Reconfiguráveis, 4-5 Fevereiro 2010, IEETA, Universidade de Aveiro, Aveiro, Portugal. ... Full text not available from this repository. ... OA.uninova.pt is powered by EPrints 3 which is developed by the School of Electronics and Computer Science at the University of Southampton. More information and software credits.
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This work presents some new ways to analyze a signal that allows the modeling of human-system interactions. In addition to the possibility of creating conditions associated with the current value of the signal, the work focuses mainly on... more
This work presents some new ways to analyze a signal that allows the modeling of human-system interactions. In addition to the possibility of creating conditions associated with the current value of the signal, the work focuses mainly on the definition of events and on their use within Input-Output Place-Transition (IOPT) nets models. Currently, non-autonomous events can be defined in two different ways, namely as a threshold detection of a signal, or variation of the first derivative of the signal. Here, this concept is generalized, allowing the analysis of events in higher derivatives of the signal. On the other hand, a new set of types of events are defined for each derivative of the signal, improving existing UP and DOWN events. Finally, an example is used to illustrate discussed concepts.
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This paper presents a controller architecture targeted for autonomous sailing of a small yacht, having in mind its control within a regatta contest. The controller architecture considers a three layer hierarchical decomposition, where the... more
This paper presents a controller architecture targeted for autonomous sailing of a small yacht, having in mind its control within a regatta contest. The controller architecture considers a three layer hierarchical decomposition, where the bottom layer takes care of the low level control of the sail and the rudder, based on the usage of a fuzzy controller, while the middle one selects the adequate navigation strategy (avoiding no-go zone), and the top layer is responsible for the definition of the regatta sequence of intermediate and final goals. A model-based development strategy is used, relying as much as possible on automatic code generation from models. Initial electronic instrumentation support comes from a compass, a GPS and a wind vane, but current developments include addition of an anemometer (providing wind speed and direction), as well as the introduction of virtual sensors obtained from computation of sensor data (as velocity obtained from GPS). A framework allowing the emulation of the different electronic instrumentation components support a complete offline validation of the controller, in a laboratory environment.
Research Interests: Engineering and Emulation
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In this paper it is shown a system for the emulation of electronic instrumentation devices used in a sailboat (a scale model) capable of sailing autonomously. The emulated devices are a wind vane sensor, a compass sensor and a GPS... more
In this paper it is shown a system for the emulation of electronic instrumentation devices used in a sailboat (a scale model) capable of sailing autonomously. The emulated devices are a wind vane sensor, a compass sensor and a GPS receiver, that allow the laboratory recreation of sailing conditions through the communication protocols involved. The emulation system, implemented with an Arduino board, is also capable of acquiring sensor data when in a real world scenario for a later indoor reproduction (emulation), being also interconnected with a computer program that allows the analysis of the taken path as well defining new sailing routes to perform. The emulation system also provides support to validate inside the lab different control strategies for specific navigation situations (as far as only the wind vane can be manually adjusted, as GPS receiver does not properly work inside the laboratory, as well as the electronic compass cannot be fully cheated).
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With the growing need for STEM workers in the job market, schools tend to look for extra-curricular activities that promote this type of skills. With activities like The Inventors or Happy Code, schools encourage kids to have a mindset... more
With the growing need for STEM workers in the job market, schools tend to look for extra-curricular activities that promote this type of skills. With activities like The Inventors or Happy Code, schools encourage kids to have a mindset more open towards technology. Despite these efforts, the tools available to teach programming to primary school students are still lacking. Available solutions can be too difficult to understand, overly expensive for school budgets or may require IT infrastructure that is lacking from the majority of public schools. As a result, this paper aims to create a concept that can convey the fundamentals of programming/Logical Thinking in an accessible and fun way, without using a computer. For this purpose we use a micro-controller, Micro: Bit, and a physical, puzzle-like representation of a programming framework, called MakeCode.
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Abstract This paper presents the planned and on-going activities inside the FORDESIGN research project, funded by the Portuguese FCT (Foundation for Science and Technology), whose main objective is to foster the effective use of formal... more
Abstract This paper presents the planned and on-going activities inside the FORDESIGN research project, funded by the Portuguese FCT (Foundation for Science and Technology), whose main objective is to foster the effective use of formal methods for embedded systems co-design. The project proposes a methodology where the use-cases are used as a starting point, not only for capturing requirements but also to support sub-model compositions. The methodology will support several different graphical formalisms, namely state diagrams, ...
Research Interests: Computer Science, XML, Embedded Systems, Hardware Description Languages, Science and Technology, and 13 morePetri Nets, Hardware/Software Co-Design, Formal Specification, Formal method, Formal Verification, Model Composition, Petri Net, Use Case, Automatic code generation, Sequence Diagram, Unified Modeling Language, Embedded System, and Hierarchical Structure
Abstract We propose a set of procedures addressing the implementation of statechart models. The main goal of this set of procedures is to lift the structuring mechanisms presented in statecharts to the top level. In this sense, the... more
Abstract We propose a set of procedures addressing the implementation of statechart models. The main goal of this set of procedures is to lift the structuring mechanisms presented in statecharts to the top level. In this sense, the complexity of statechart implementation will be similar to the complexity of communicating concurrent state machines and the platforms selected to support implementation will not need to have specific capabilities to directly support the structuring mechanisms of Harel's statecharts. The ...
Research Interests: History, Computer Science, Embedded Software, Industrial Automation, Hardware Description Languages, and 10 moreVhdl, Hardware, Formal Specification, Formal Verification, Hardware Implementation of Algorithms, Embedded System, Realtime System, Application Software, Concurrent Computing, and state machine
In this paper, a new approach to define output actions associated with output event types for human-system interaction modeling is presented. In previous works, output events are used to affect a signal in a basic way: increment,... more
In this paper, a new approach to define output actions associated with output event types for human-system interaction modeling is presented. In previous works, output events are used to affect a signal in a basic way: increment, decrement or set its value in the next time instant. This work proposes a set of new types of events to define different dependencies and behaviors for output signals. These events affect the associated signal with a specific behavior, which can be defined using specific characteristics including a function, a time window, and/or a final value. The concepts of delayed output events and zoomed output event are already proposed. Delayed events postpone the event contribution in a specific number of steps. Zoomed events change the number of steps between each contribution, allowing expanding and contracting the associated behavior. These concepts can be applied to previous types of events. Finally, the proposals are discussed, presenting some examples of usage for each type of events.
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Abstract Model based development within the area of hardware-software embedded systems co-design has been used as a major attitude to support embedded system complexity increasing during the last decade. Several modeling formalisms are... more
Abstract Model based development within the area of hardware-software embedded systems co-design has been used as a major attitude to support embedded system complexity increasing during the last decade. Several modeling formalisms are very well matched for usage within this area. One of the main goals of the work presented in this paper is to contribute for the usage of Petri nets as the system-level specification language within model-based development of embedded systems using co-design techniques. ...
Research Interests: Computer Science, Embedded Systems, Embedded Software, Petri Nets, Reliability Engineering, and 11 moreHardware, Design Methodology, Communication Channels, Model based development, Petri Net, Specification Language, Synchronous Communication, Unified Modeling Language, System modeling, Software Systems, and Embedded System
Abstract This paper addresses a laboratory work, within a digital system design course, where logical equivalency between hardware and software implementations is exercised. The exercise starts with the well-known system decomposition... more
Abstract This paper addresses a laboratory work, within a digital system design course, where logical equivalency between hardware and software implementations is exercised. The exercise starts with the well-known system decomposition attitude, partitioning the system into control and data path, and giving ground for understanding co-design techniques within embedded system design development process. A comprehensive didactic example is used for illustrating the techniques, built around the well-known ...
Research Interests: Computer Science, Computer Architecture, Intellectual Property, Embedded Systems, FPGA, and 14 moreField-Programmable Gate Arrays, Control Systems, IP, Software, Hardware, Process Design, Microcontroller, Field Programmable Gate Array, Implementation, Development Process, Reconfigurability, Embedded System, Attitude Control, and Software Performance
Abstract 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... more
Abstract 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 ...
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The paper presents a novel design methodology of cyber-physical systems supported by computer aided tools. In particular, IOPT and Hippo tools are involved in the design and analysis techniques of the system. The proposed idea combines... more
The paper presents a novel design methodology of cyber-physical systems supported by computer aided tools. In particular, IOPT and Hippo tools are involved in the design and analysis techniques of the system. The proposed idea combines the main advantages of both tools by offering the complex design path of the control part of the cyber-physical system, including specification, analysis and verification, decomposition, and modelling stages. Additionally, the designer is able to choose the most suitable representation of the system (graphical or formal). The presented concepts are illustrated by a case-study example.
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In this paper it is shown a collision avoidance system intended to be used on an autonomous sailboat scale model. The sailboat has a sequence of route points in the controller memory which are followed sequentially, as for a typical... more
In this paper it is shown a collision avoidance system intended to be used on an autonomous sailboat scale model. The sailboat has a sequence of route points in the controller memory which are followed sequentially, as for a typical regatta contest. The system is based on a camera device named Pixy and a low-cost Arduino board. The image data obtained from Pixy is edited considering the inclination of the sailboat, wind speed, water current and sea ripple and the number of obstacles. The data is then used and considered in a function that change the next destination point in presence of a collision warning. The methods and functions were validated using MATLAB simulation and some of them implemented on Arduino.
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Petri nets have been widely used in the design of embedded controllers, namely in electronic hardware and computing platforms design, as well as within automation application areas. This paper presents updated characteristics of one class... more
Petri nets have been widely used in the design of embedded controllers, namely in electronic hardware and computing platforms design, as well as within automation application areas. This paper presents updated characteristics of one class of Petri nets, named Input-Output Place-Transition Petri nets (IOPT nets), extended to support networked embedded controllers design and globally-asynchronous locally-synchronous (GALS) systems modeling, together with its associated metamodel and execution semantics. The proposed meta-model is compliant with the Petri Net Markup Language (PNML) metamodel, augmented with the descriptions for inputs and outputs, as well as for time domains and communication channels. The meta-model is described using UML class diagrams and has an equivalent Ecore meta-model that positioning IOPT nets within the Eclipse Modeling Framework (EMF).
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This paper addresses the use of events within discrete-event systems modeling formalisms, presenting the concept of event life time when enclosed in the detection of a specific behavior defined by sequences of events. This concept defines... more
This paper addresses the use of events within discrete-event systems modeling formalisms, presenting the concept of event life time when enclosed in the detection of a specific behavior defined by sequences of events. This concept defines the time interval during which a macro-event is valid (a macro-event is an event computed as the result of a pre-defined sequence of events). Two types of life times are defined: Absolute and Relative. Absolute life time is associated with the maximum time between the occurrence of the first and last event in the sequence. The relative life time is associated with each elementary event from the sequence and is defined by minimum and maximum values among which the next event in the sequence must occur. If the next event does not occur during the defined time, the event expires. Finally the use of these concepts is discussed presenting some specific cases of use.
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This paper presents activities carried on during a short course (five days long) offered to high school students devoted to autonomous yacht sailing. The main goal of the course is to expose high school students to several development... more
This paper presents activities carried on during a short course (five days long) offered to high school students devoted to autonomous yacht sailing. The main goal of the course is to expose high school students to several development techniques and technological solutions used to produce electronic controller systems and attracting them to STEM (science, technology, engineering and mathematics) courses.
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Research Interests: Computational Modeling, Systems Engineering, Embedded Systems, Software Architecture, Embedded Software, and 12 moreHardware, Formal Specification, Real Time Systems, Use Case, Unified Modeling Language, Concurrent Design, Data Processing, Embedded Computing, System Implementation, Embedded System, Concurrent Computing, and state machine
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Abstract In recent years, we have witnessed the emerging trend in industrial informatics of joining web-services technologies in the embedded system's design. In one hand web-services turns lower the integration... more
Abstract In recent years, we have witnessed the emerging trend in industrial informatics of joining web-services technologies in the embedded system's design. In one hand web-services turns lower the integration efforts of several technological entities through platform-independent interfaces. On the other hand it is well-known that embedded systems are everywhere, taking a great amount of research in design approaches due to their increasing complexity. Back to the first hand, the Web Services Business Process Execution ...
Research Interests: Computer Science, Computer Architecture, Informatics, Service Oriented Architecture, Embedded Systems, and 15 moreSoftware Architecture, Petri Nets, Model Transformation, Protocols, Formal Specification, Formal method, Levels of Abstraction, Business Process, Petri Net, Web Service, Specification Language, Input Output, Model Driven Architecture, Formal Specifications, and Embedded System
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ABSTRACT In this paper, a set of event types for human-system interaction modeling is presented, and its usage with IOPT nets (Input-Output Place-Transition Petri nets) models is illustrated. Currently, a non-autonomous event based on the... more
ABSTRACT In this paper, a set of event types for human-system interaction modeling is presented, and its usage with IOPT nets (Input-Output Place-Transition Petri nets) models is illustrated. Currently, a non-autonomous event based on the computation of the change with respect to a specific threshold of input signals values on two consecutive execution steps is defined for IOPT models. Other types of events are proposed, allowing the definition of an event not only based on a threshold in the signal value, but also as a change on the variation of the signal. The concept of delayed events considers two values in different time steps (other than consecutive steps). This concept can be applied to previous types of events. The concept of composed events is also introduced, in order to create events dependent on two or more events on the same signal, at the same time step as well as at different time steps. Finally, an example is used to illustrate the concepts presented.
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Abstract This paper shows how to transform the input part of a class of non-autonomous Petri net models into behaviorally equivalent autonomous models. To that end, it proposes a set of transformations and compositions to replace... more
Abstract This paper shows how to transform the input part of a class of non-autonomous Petri net models into behaviorally equivalent autonomous models. To that end, it proposes a set of transformations and compositions to replace non-autonomous annotations by structurally equivalent net modules. The resulting model can be analyzed by existing tools for autonomous Place/Transition nets supporting a maximal step semantics and, preferably, priorities in transitions. This possibility was tested using a freely available analysis tool for ...
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Abstract In the last decades, embedded system controllers design is facing sustainable increasing complexity. This brings new challenges that can benefit from model based development approaches. Petri nets are one of the formalisms... more
Abstract In the last decades, embedded system controllers design is facing sustainable increasing complexity. This brings new challenges that can benefit from model based development approaches. Petri nets are one of the formalisms suitable to be used as system specification language. This paper proposes a method for model composition, starting from sub-models representing concurrent components, and relying on their composition using a bottom-up approach, while supporting the reusability of modules. This bottom-up ...
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Abstract This paper presents a model-based development approach to support automatic code generation for Globally-Asynchronous Locally-Synchronous (GALS) embedded systems. FPGA-based platforms are used to validate the proposed approach.... more
Abstract This paper presents a model-based development approach to support automatic code generation for Globally-Asynchronous Locally-Synchronous (GALS) embedded systems. FPGA-based platforms are used to validate the proposed approach. The GALS system behavior must be specified using a class of Petri nets, which allows the specification of the components and how they interact. A verification tool is used to automatically obtain the characteristics of the communication infrastructure, namely the buffer size required to ...
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ABSTRACT In this work a model for an e-learning system is proposed for managing a dynamic educational system that, in addition to supervise the students' evolution throughout the course, allows the student to elaborate his/her... more
ABSTRACT In this work a model for an e-learning system is proposed for managing a dynamic educational system that, in addition to supervise the students' evolution throughout the course, allows the student to elaborate his/her study plan. The system has two distinct phases. The first phase where the student can visualize all the paths (sequences of modules) in which he/she can obtain his/her qualification, and select which one has the better fit with his/her requirements. The second phase allows the management of the student's evolution obtaining his/her qualification. For this purpose, models expressed in High-Level Petri nets are used, to model each module, as well the entire study plan interdependencies. This paper focuses mainly in the first phase, relying on the construction of the state space associated with the Petri net model of the study plan. The analysis of the generated state space is used to obtain all possible sequence of modules according with desired goals. Applying a set of queries to these results, students are able to obtain information on possible sequences of modules accomplishing his/her goals and requirements and select the best option.
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Abstract Model Based Development within the area of embedded systems hardware-software co-design has been demonstrated to be effective to handle system complexity. Several modeling formalisms are widely used within this area. The work... more
Abstract Model Based Development within the area of embedded systems hardware-software co-design has been demonstrated to be effective to handle system complexity. Several modeling formalisms are widely used within this area. The work presented in this paper aims to contribute for the usage of Petri nets as the system-level specification language within model-based development of embedded systems using co-design techniques. System model partitioning into modules and components ready to be ...
Research Interests:
Abstract Petri nets are a well-known formalism widely used in different application areas. Yet, the lack of adequate tools that can be integrated within engineering development frameworks are one major drawback. This paper identifies and... more
Abstract Petri nets are a well-known formalism widely used in different application areas. Yet, the lack of adequate tools that can be integrated within engineering development frameworks are one major drawback. This paper identifies and justifies the characteristics of one class of Petri nets targeted for the modelling of automation systems and (networked) embedded systems, named as input-output Petri net (IOPT), and its representation using the Petri net markup language (PNML). The paper also presents a set of associated tools ...
Research Interests: Computer Science, Animation, Embedded Systems, Conflict Resolution, Petri Nets, and 12 moreSignal Analysis, Automation, State Space, Markup Languages, System Development, Petri Net, Automatic code generation, Discrete Event Simulation, Input Output, Embedded System, Automation System, and DT Signal+generators
ABSTRACT This paper addresses the distributed execution of IOPT Petri nets models supported by a network of distributed controllers. Each controller is associated with a sub-model. Submodels use communication channels to exchange events... more
ABSTRACT This paper addresses the distributed execution of IOPT Petri nets models supported by a network of distributed controllers. Each controller is associated with a sub-model. Submodels use communication channels to exchange events allowing global evolution. Whenever controllers are interconnected through some kind of network, communication channels are implemented by communication nodes associated with each distributed controller. Communication nodes are characterized in terms of layers and buffers allowing their use with different types of communication and topologies. Their usage in a simple application example composed by a network of distributed controllers interconnected through a serial ring topology network is presented. Arduino boards are used as implementation platforms for proof-of-concept purposes.
Research Interests: Computer Science and IEEE
Research Interests: Computer Science, Intellectual Property, Field-Programmable Gate Arrays, Petri Nets, Digital Control, and 13 moreMicrocontrollers, digital PID controller, Automatic question generation, Generators, Field Programmable Gate Array, Communication Channels, Model based development, Petri Net, Tool Development, Automatic code generation, Input Output, Programming language, and Digital controller
Abstract This paper aims to present a development environment that enables the automatic code generation amenable for the interconnection of components obtained as a result of the partition of a Petri net model addressing its distributed... more
Abstract This paper aims to present a development environment that enables the automatic code generation amenable for the interconnection of components obtained as a result of the partition of a Petri net model addressing its distributed execution using networked controllers (including microcontrollers and FPGAs devices, as well as specific controllers based on PLCs and general purpose PCs). The proposed interconnection solution is based on a Network-on-Chip solution supporting communications based on RS-232 serial protocol ( ...