El Director General inaugura simb��licamente en Sancti Petri (C��diz) 102 nuevas aulas de audici��n del bachillerato radiof��nico.

Se describen los actos de inauguraci��n de las nuevas ciento dos aulas de audici��n colectiva del Bachillerato Radiof��nica promovidas por la Comisar��a de Extensi��n Cultural en C��diz, Murcia y Tenerife, en las que recibir��n formaci��n, por procedimientos radio-auditivos 6000 alumnos. El encargado de presidir dichos actos es el Director General de Ense��anza Media, Profesor Gonz��lez ��lvarez, acompa��ado del Inspector General y Secretario T��cnico de la Direcci��n General, Sr. Del Arco. Se reproduce el discurso del Director General en el que pone de manifiesto su satisfacci��n al saber que se cubrir��n las necesidades de formaci��n de muchos alumnos interesados en completar su instrucci��n. Seguidamente, se describe la visita de estas autoridades al Instituto Femenino de C��diz y la posterior inauguraci��n de otras tres Aulas de Audici��n en la localidad de Alcal�� de los Gazules. Culmin�� su periplo por tierras gaditanas con la visita al Instituto masculino 'Columela' en C��diz, d��nde convers�� con los profesores sobre distintos aspectos de la ense��anza.

Economists are not dismal, the world is not a Petri dish and other reasons for optimism

One of the recurrent themes in the debate around how to ensure global food security concerns the capacity of the planet to support its growing population. Neo-Malthusian thinking suggests that we are in a situation in which further expansion of the population cannot be supported and that the population checks, with their dismal consequences envisaged by Malthus, will lead to a new era of stagnant incomes and population. More sophisticated models of the link between population and income are less gloomy however. They see population growth as an integral component of the economic growth which is necessary to ensure that the poorest achieve food security. An undue focus on the difficulties of meeting the demands of the increasing population risks damaging this growth. Instead, attention should be focused on ensuring that the conditions to ensure that economic growth accompanies population growth are in place.

Elementary Petri net inside RFID distributed database (PNRD)

Usually, a Petri net is applied as an RFID model tool. This paper, otherwise, presents another approach to the Petri net concerning RFID systems. This approach, called elementary Petri net inside an RFID distributed database, or PNRD, is the first step to improve RFID and control systems integration, based on a formal data structure to identify and update the product state in real-time process execution, allowing automatic discovery of unexpected events during tag data capture. There are two main features in this approach: to use RFID tags as the object process expected database and last product state identification; and to apply Petri net analysis to automatically update the last product state registry during reader data capture. RFID reader data capture can be viewed, in Petri nets, as a direct analysis of locality for a specific transition that holds in a specific workflow. Following this direction, RFID readers storage Petri net control vector list related to each tag id is expected to be perceived. This paper presents PNRD cornerstones and a PNRD implementation example in software called DEMIS Distributed Environment in Manufacturing Information Systems.

Verifica����o formal automatizada para sistemas de racioc��nio procedural (PRS) utilizando redes de petri coloridas (RPC)

Este trabalho apresenta uma t��cnica de verifica����o formal de Sistemas de Racioc��nio Procedural, PRS (Procedural Reasoning System), uma linguagem de programa����o que utiliza a abordagem do racioc��nio procedural. Esta t��cnica baseia-se na utiliza����o de regras de convers��o entre programas PRS e Redes de Petri Coloridas (RPC). Para isso, s��o apresentadas regras de convers��o de um sub-conjunto bem expressivo da maioria da sintaxe utilizada na linguagem PRS para RPC. A fim de proceder fia verifica����o formal do programa PRS especificado, uma vez que se disponha da rede de Petri equivalente ao programa PRS, utilizamos o formalismo das RPCs (verifica����o das propriedades estruturais e comportamentais) para analisarmos formalmente o programa PRS equivalente. Utilizamos uma ferramenta computacional dispon��vel para desenhar, simular e analisar as redes de Petri coloridas geradas. Uma vez que disponhamos das regras de convers��o PRS-RPC, podemos ser levados a querer fazer esta convers��o de maneira estritamente manual. No entanto, a probabilidade de introdu����o de erros na convers��o �� grande, fazendo com que o esfor��o necess��rio para garantirmos a corretude da convers��o manual seja da mesma ordem de grandeza que a elimina����o de eventuais erros diretamente no programa PRS original. Assim, a convers��o automatizada �� de suma import��ncia para evitar que a convers��o manual nos leve a erros indesej��veis, podendo invalidar todo o processo de convers��o. A principal contribui����o deste trabalho de pesquisa diz respeito ao desenvolvimento de uma t��cnica de verifica����o formal automatizada que consiste basicamente em duas etapas distintas, embora inter-relacionadas. A primeira fase diz respeito fias regras de convers��o de PRS para RPC. A segunda fase �� concernente ao desenvolvimento de um conversor para fazer a transforma����o de maneira automatizada dos programas PRS para as RPCs. A convers��o autom��tica �� poss��vel, porque todas as regras de convers��o apresentadas seguem leis de forma����o gen��ricas, pass��veis de serem inclu��das em algoritmos

Arquitetura multiprocessada e reconfigur��vel para a s��ntese de redes de Petri em hardware

Uma arquitetura reconfigur��vel e multiprocessada para a implementa����o f��sica de Redes de Petri foi desenvolvida em VHDL e mapeada sobre um FPGA. Convencionalmente, as Redes de Petri s��o transformadas em uma linguagem de descri����o de hardware no n��vel de transfer��ncias entre registradores e um processo de s��ntese de alto n��vel �� utilizado para gerar as fun����es booleanas e tabelas de transi����o de estado para que se possa, finalmente, mape��-las num FPGA (Morris et al., 2000) (Soto and Pereira, 2001). A arquitetura proposta possui blocos l��gicos reconfigur��veis desenvolvidos exclusivamente para a implementa����o dos lugares e das transi����es da rede, n��o sendo necess��ria a descri����o da rede em n��veis de abstra����o intermedi��rios e nem a utiliza����o de um processo de s��ntese para realizar o mapeamento da rede na arquitetura. A arquitetura permite o mapeamento de modelos de Redes de Petri com diferencia����o entre as marcas e associa����o de tempo no disparo das transi����es, sendo composta por um arranjo de processadores reconfigur��veis, cada um dos quais representando o comportamento de uma transi����o da Rede de Petri a ser mapeada e por um sistema de comunica����o, implementado por um conjunto de roteadores que s��o capazes de enviar pacotes de dados de um processador reconfigur��vel a outro. A arquitetura proposta foi validada num FPGA de 10.570 elementos l��gicos com uma topologia que permitiu a implementa����o de Redes de Petri de at�� 9 transi����es e 36 lugares, atingindo uma lat��ncia de 15,4ns e uma vaz��o de at�� 17,12GB/s com uma freq����ncia de opera����o de 64,58MHz.

A petri net based timing model for hardware/software co-design of digital systems

We have recently proposed an extension to Petri nets in order to be able to directly deal with all aspects of embedded digital systems. This extension is meant to be used as an internal model of our co-design environment. After analyzing relevant related work, and presenting a short introduction to our extension as a background material, we describe the details of the timing model we use in our approach, which is mainly based in Merlin's time model. We conclude the paper by discussing an example of its usage. �� 2004 IEEE.

Petri nets teaching in the Mechatronics Engineering course

The current solutions implanted in the majority of manufacturing systems controlled by PLCs were developed through the language of programming known as ladder. Such a language, easily learned and handled, shows to be efficient whenever the system to be implanted does not demand greater complexity of analyses. Bigger systems, presenting characteristics in which resource compartments, parallelism and synchronizing among processes are more frequent, demand the adoption of solutions differentiation. This article presents a teaching experience and practical application of Petri nets in a Mechatronics Engineering graduation course. Copyright �� 2007 IFAC.

Petri nets and autonomous systems: A case study

This work presents the Petri net-based modeling of an autonomous robot's navigation system used for the application of supplies in agriculture. The model was developed theoretically and implemented through the CPNTools software. It simulates the behavior of the robot, capturing environmental characteristics by means of sensors, making appropriate decisions, and forwarding them to the corresponding actuators. By exciting the model using CPNTools it is possible to simulate situations that the robot might undergo, without the need to expose it to real potentially dangerous situations. ��2009 IEEE.

Digital system design process automation using place/transition petri nets

The constant increase in digital systems complexity definitely demands the automation of the corresponding synthesis process. This paper presents a computational environment designed to produce both software and hardware implementations of a system. The tool for code generation has been named ACG8051. As for the hardware synthesis there has been produced a larger environment consisting of four programs, namely: PIPE2TAB, AGPS, TABELA, and TAB2VHDL. ACG8051 and PIPE2TAB use place/transition net descriptions from PIPE as inputs. ACG8051 is aimed at generating assembly code for the 8051 micro-controller. PIPE2TAB produces a tabular version of a Mealy type finite state machine of the system, its output is fed into AGPS that is used for state allocation. The resulting digital system is then input to TABELA, which minimizes control functions and outputs of the digital system. Finally, the output generated by TABELA is fed to TAB2VHDL that produces a VHDL description of the system at the register transfer level. Thus, we present here a set of tools designed to take a high-level description of a digital system, represented by a place/transition net, and produces as output both an assembly code that can be immediately run on an 8051 micro-controller, and a VHDL description that can be used to directly implement the hardware parts either on an FPGA or as an ASIC.

Automatic code generation for microcontrollers from place-transition Petri net models

This paper describes a program for the automatic generation of code for Intel's 8051 microcontroller. The code is generated from a place-transition Petri net specification. Our goal is to minimize programming time. The code generated by our program has been observed to exactly match the net model. It has also been observed that no change is needed to be made to the generated code for its compilation to the target architecture. �� 2011 IFAC.

Finding best urban routes based on analyses of high level and IOPT Petri net models

This paper presents a tool that combines two kinds of Petri Net analyses to set the fastest routes to one vehicle in a bounded area of traffic urban. The first analysis consists of the discovery of possible routes in a state space generated from an IOPT Petri net model given the initial marking as the vehicle position. The second analysis receives the routes found in the first analysis and calculates the state equations at incidence matrix created from the High Level Petri net model to define the fastest route for each vehicle that arrive in the roads. It was considered the exchange of information between vehicle and infrastructure (V2I) to get the position and speed of all vehicles and support the analyses. With the results obtained we conclude that is possible optimizing the urban traffic flow if this tool is applied to all vehicles in a bounded urban traffic. �� 2012 IEEE.

Controlling traffic jams on urban roads modeled in Coloured Petri net using Genetic Algorithm

This paper presents an application to traffic lights control in congested urban traffic, in real time, taking as input the position and route of the vehicles in the involved areas. This data is obtained from the communication between vehicles and infrastructure (V2I). Due to the great complexity of the possible combination of traffic lights and the short time to get a response, Genetic Algorithm was used to optimize this control. According to test results, the application can reduce the number of vehicles in congested areas, even with the entry of vehicles that previously were not being considered in these roads, such as parked vehicles. �� 2012 IEEE.

Ferramentas para a integra����o de redes de Petri e VHDL na s��ntese de sistemas digitais

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Compara����o de t��cnicas de redes de Petri na descri����o de um pipeline

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)