Synthesis a Petri net based control model for a FMS cell

Petri nets have been recognised as a high level formal and graphical specification language for modelling, analysis, and control of concurrent asynchronous distributed systems. This paper presents a PN model, synthesised by an extended version of the knitting synthesis technique. This method, as an incremental design approach, establishes the conditions under which the fundamental behavioural properties of the synthesised systems are fulfilled and preserved. That is, the synthesised models are live, bounded, and reversible (cyclic). A Petri net with the aforementioned properties is called a well-behaved Petri net system which is guaranteed to operate in a deadlock-free, stable, and cyclic fashion. Well-behaved Petri net models, synthesised using the proposed method can be compiled into control codes and implemented as real-time controllers for flexible manufacturing systems. The significance of this paper is due to the application of an extended version of knitting synthesis technique to a real life example of a flexible manufacturing system.     

An adaptive system for modelling and simulation of electrical arc furnaces

Modelling and simulator development for electric arc furnaces (EAFs) are of significant importance in designing control systems and in performance optimisation of EAFs. This paper presents a method based on adaptive neuro-fuzzy inference systems (ANFIS) for modelling and simulating EAFs with the focus on the regulator loop that is used for positioning the electrodes. The effectiveness of the simulator is shown through experiments by comparing the simulator outputs with actual plant data, using the EAF of Gerdau Ameristeel Whitby (GAW) in Ontario, Canada.     

Flexible coordinator design for modeling resource sharing in multi-agent systems

One approach to modeling multi-agent systems (MASs) is to employ a method that defines components which describe the local behavior of individual agents, as well as a special component, called a coordinator. The coordinator component coordinates the resource sharing behavior among the agents. The agent models define a set of local plans, and the combination of local plans and a coordinator defines a system’s global plan. Although earlier work has provided the base functionality needed to synthesize inter-agent resource sharing behavior for a global, conflict-free MAS environment, the lack of coordination flexibility limits the modeling capability at both the local plan level and the global plan level. In this paper, we describe a flexible design method that supports a range of coordinator components. The method defines four levels of coordination and an associated four-step coordinator generation process, which allows for the design of coordinators with increasing capabilities for handling complexity associated with resource coordination. Colored Petri net based simulation is used to analyze various properties that derive from different coordinators and synthesis of a reduced coordinator component is discussed for cases that involve homogeneous agents.     

Hardware options,evaluation metrics,and a design sequence for interactive information systems

Interactive information systems must satisfy a wide variety of users, serve a broad range of tasks, and be suited to diverse hardware environments. This paper concentrates on three aspects of interactive information systems design: hardware options, evaluation metrics, and a possible design sequence. Rigorous pilot studies are emphasized, and supporting experimental evidence is offered.     

EXPSPACE lower bounds for the simulation preorder between a communication-free Petri net and a finite-state system

We investigate the simulation preorder between finite-state systems and a simple subclass of BPP-nets (communication-free nets). We show EXPSPACE lower bounds for the simulation problems, in both directions, as well as for the simulation equivalence. Our results improve PSPACE and co-NP lower bounds for the simulation between finite-state systems and BPP-nets, given by Ku?era and Mayr in [A. Ku?era, R. Mayr, Simulation preorder over simple process algebras, Information and Computation 173 (2) (2002) 184-198].     

A distributed and interactive system to integrated design and simulation for collaborative product development

The goal of applying collaborative product development in industry has raised the need to develop software tools supporting system integration and group collaboration. Current methods and tools mainly focus on the collaborative creation of design components and assemblies. However, few of them support the collaborative work in developing simulation models so that proposed design concepts and solutions can be evaluated by integrating expertise from several disciplines. The purpose of this research is to develop a distributed and interactive system on which designers and experts can work together to create, integrate and run simulations for engineering design. To develop such a system, a number of issues, e.g. effectiveness and efficiency of modeling work, the re-use of models, interaction and cooperation, accuracy of simulation, collaborative operation on models, etc., need to be addressed. This paper describes an open architecture to developing simulations for engineering design in a distributed and collaborative environment, identifies a set of key issues raised in this architecture, and presents the techniques employed in our solution.     

PROTOB: An object-oriented case tool for modelling and prototyping distributed systems

The PROTOB object-oriented methodology for the executable specification of large-scale event-driven systems is introduced and described. Two supporting features of PROTOB are also presented: the graphic and textual language that formally describes the behaviour of objects, which is based on high-level Petri nets called “PROT nets” and which is demonstrated to be more powerful than SA/RT dataflows; and a CASE environment with tools for specification, modelling, simulation and prototyping. Use of PROTOB is illustrated by discussion of the automated generation of distributed systems running on a network of VMS and UNIX computers.     

On model design for simulation of collective intelligence

The study of collective intelligence (CI) systems is increasingly gaining interest in a variety of research and application domains. Those domains range from existing research areas such as computer networks and collective robotics to upcoming areas of agent-based and insect-based computing; also including applications on the internet and in games and movies. CI systems are complex by nature and (1) are effectively adaptive in uncertain and unknown environments, (2) can organise themselves autonomously, and (3) exhibit ‘emergent’ behaviour. Among others, multi-agent systems, complex adaptive systems, swarm intelligence and self-organising systems are considered to be such systems. The explosive wild growth of research studies of CI systems has not yet led to a systematic approach for model design of these kinds of systems. Although there have been recent efforts on the issue of system design (the complete design trajectory from identifying system requirements up to implementation), the problem of choosing and specifying a good model of a CI system is often done implicitly and sometimes even completely ignored. The aim of this article is to bring to the attention that model design is an essential as well as an integral part of system design. We present a constructive approach to systematically design, build and test models of CI systems. Because simulation is often used as a way to research CI systems, we particularly focus on models that can be used for simulation. Additionally, we show that it is not necessary to re-invent the wheel: here, we show how existing models and algorithms can be used for CI model design. The approach is illustrated by means of two example studies on a (semi-automated) multi-player game and collaborative robotics.     

EJS+EjsRL: An interactive tool for industrial robots simulation, Computer Vision and remote operation

This paper presents an interactive Java software platform which enables users to easily create advanced robotic applications together with Computer Vision processing. This novel tool is composed of two layers: (1) Easy Java Simulations (EJS), an open-source tool which provides support for creating applications with a full 2D/3D interactive graphical interface, and (2) EjsRL, a high-level Java library specifically designed for EJS which provides a complete functional framework for modeling and simulation of arbitrary serial-link manipulators, Computer Vision algorithms and remote operation. The combination of both components sets up a software architecture which contains a high number of functionalities in the same platform to develop complex simulations in Robotics and Computer Vision fields. In addition, the paper shows its successful application to virtual and remote laboratories, web-based resources that enhance the accessibility of experimental setups for education and research.     

一种知识库校验工具PKBV的设计与实现

以Petri网建模基于规则的知识库,并据此开发出知识库校验工具PKBV,该工具通过对Petri网可达性及不变量的分析计算,来检查知识库中常见的完整性与一致性错误,针对具有多领域知识库的复杂系统,PKBV具有抽取多领域知识库之间的关联规则并进行校验的功能,满足了复杂知识系统的校验需求。     

Approximate methods for simulation and verification of numerically controlled machining programs

Algorithms for simulation and verification of Numerically Controlled (NC) machining programs are presented. Compared to NC simulation based on conventional solid modeling systems, these models are designed to give approximate results, but with a substantial decrease in computer time. The surfaces of the part are discretized into a Surface Point Set (SPS) with a point spacing dependent on cutting tool size and shape local surface curvature and the desired accuracy of the approximate simulation. The surface-surface intersection calculations of the solid modeling approach are replaced by the intersection of the surface of the tool movement envelope with straight lines emanating from the surface points. The methods are applicable to both 3 and 5 axis machining. Samples test cases are presented, and implementation and efficiency issues are discussed.     

An integrated approach for simulation of mechatronic systems applied to a hexapod robot

Mechatronics is the integration of mechanism, electronics and computer control to produce a functional system. The design process involves application of many engineering areas and various approaches are possible. Computer programs are available in different engineering areas. Engineers define systems and inputs, and user-friendly programs establish mathematical models, solve them and give simulation outputs. In this study, SolidWorks is used for solid modeling and assembly, CosmosMotion is used for rigid body dynamics, CosmosWorks is used for finite element vibration and strength analyses, and Adlink module is used for actuator control. The integration of the design process is achieved with a main program developed in Visual Basic, which uses the application programming interface (API) capabilities. The procedure is applied to a hexapod robot. The robot has been produced to develop and test the procedure. CosmosMotion results are verified by the analytical results obtained from the dynamic equations of the hexapod. Besides known kinematic workspace definition of robots, kinetic and rigidity workspace concepts are introduced. Mechatronic systems can be designed and evaluated easily and effectively by using the design process developed in this work.     

The Daktari: An interactive,multi-media tool for knowledge transfer among poor livestock keepers in Kenya

This article describes the findings from the assessment of a touch-screen, multi-media learning program on livestock health and production: The Daktari. The program was tested on a sample of 62 livestock keepers in the Nairobi slums of Kariobangi and Kibera. The study examined prior knowledge regarding three livestock diseases (liver fluke, mastitis and mange) and compared this to newly acquired knowledge after exposure to the software. The results demonstrated a significant difference between pre- and post-knowledge assessments confirming that use of the program led to learning. Learning occurred among a variety of demographic/social groups (i.e. age, gender and education) with a range of abilities. Indeed, by utilising an audio–visual interface developed with relevant content for the population in question, it was found that the program could support and enhance participant understanding of livestock disease causation, diagnosis, treatment and prevention.     

Distributed simulation of modular time Petri nets: An approach and a case study exploiting temporal uncertainty

This paper proposes an approach to modular modelling and simulation of complex time-critical systems. The modelling language is represented by Merlin and Farber’s Time Petri Nets (TPNs) augmented with inhibitor arcs and modular constructs borrowed from the Petri Net Markup Language (PNML) interchange format. Analysis techniques depend on Temporal Uncertainty Time Warp (TUTW), a time warp algorithm capable of exploiting temporal uncertainty in general optimistic simulations over a networked context. A key feature of the approach is the fact that TPN models naturally exhibit a certain degree of temporal uncertainty which the TUTW control engine can exploit to achieve good speedup without a loss in the accuracy of the simulation results. The developed TUTW/TPN kernel is demonstrated by modelling and simulation of a real-time system example.A preliminary version of this paper was presented at 38th SCS Annual Simulation Symposium, April 4–6, 2005, San Diego (CA), IEEE Computer Society, pp. 233–240. Franco Cicirelli achieved a PhD in computer science from the University of Calabria (Unical), DEIS—department of electronics informatics and systems science. As a postdoc, he is making research on agent and service paradigms for the development of distributed systems, parallel simulation, Petri nets, distributed measurement systems. He holds a membership with ACM. Angelo Furfaro, PhD, is a computer science assistant professor at Unical, DEIS, teaching object-oriented programming. His research interests are centred on: multi-agent systems, modeling and analysis of time-dependent systems, Petri nets, parallel simulation, verification of real-time systems, distributed measurement systems. He is a member of ACM. Libero Nigro is a full professor of computer science at Unical, DEIS, where he teaches object-oriented programming, software engineering and real-time systems courses. He directs the Software Engineering Laboratory (www.lis.deis.unical.it). His current research interests include: software engineering of time-dependent and distributed systems, real-time systems, Petri nets, modeling and parallel simulation of complex systems, distributed measurement systems. Prof. Nigro is a member of ACM and IEEE.     

The semiotics of configurations for the immanent design of interactive computational systems

In this paper the authors propose a novel semiotic approach to the design of interactive systems and computational systems, grounded in the most recent contributions within the debate around semiotic theory and analysis. This approach, that is here called Semiotics of Configurations (SoC), is proposed for its analytic power in describing material artifacts and settings with a purposely a-conceptualistic stance. The resulting analysis informs a kind of design that is aimed at reproducing and supporting the programs of action detected in the use of artifacts, as this use is “abducted” from the physical and material form of the artifacts themselves and from the observation of how content is transformed within and across them. This approach to design, called immanent design, has inspired a platform for the user-driven development and use of electronic documents and forms in cooperative and organizational domains. The framework is illustrated with a case drawn from a study performed in the domain of hospital work.