Petri Nets

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 9. Petri Nets - Applications. Y Narahari. General Article Volume 4 Issue 9 September 1999 pp 44-52 ... Author Affiliations. Y Narahari1. Department of Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India.

Discrete, continuous, and hybrid petri nets

CERN Document Server

David, René

2004-01-01

Petri nets do not designate a single modeling formalism. In fact, newcomers to the field confess sometimes to be a little puzzled by the diversity of formalisms that are recognized under this "umbrella". Disregarding some extensions to the theoretical modeling capabilities, and looking at the level of abstraction of the formalisms, Condition/Event, Elementary, Place/Transition, Predicate/Transition, Colored, Object Oriented... net systems are frequently encountered in the literature. On the other side, provided with appropriate interpretative extensions, Controled Net Systems, Marking Diagrams (the Petri net generalization of State Diagrams), or the many-many variants in which time can be explicitly incorporated -Time(d), Deterministic, (Generalized) Stochastic, Fuzzy...- are defined. This represents another way to define practical formalisms that can be obtained by the "cro- product" of the two mentioned dimensions. Thus Petri nets constitute a modeling paradigm, understandable in a broad sense as "the total...

CPN Tools-Assisted Simulation and Verification of Nested Petri Nets

Directory of Open Access Journals (Sweden)

L. W. Dworza´nski

2012-01-01

Full Text Available Nested Petri nets (NP-nets are an extension of Petri net formalism within the “netswithin-nets” approach, when tokens in a marking are Petri nets, which have an autonomous behavior and are synchronized with the system net. The formalism of NP-nets allows modeling multi-level multi-agent systems with dynamic structure in a natural way. Currently, there is no tool for supporting NP-nets simulation and analysis. The paper proposes the translation of NP-nets into Colored Petri nets and the use of CPN Tools as a virtual machine for NP-nets modeling, simulation and automatic verification.

Modeling of Biometric Identification System Using the Colored Petri Nets

Science.gov (United States)

Petrosyan, G. R.; Ter-Vardanyan, L. A.; Gaboutchian, A. V.

2015-05-01

In this paper we present a model of biometric identification system transformed into Petri Nets. Petri Nets, as a graphical and mathematical tool, provide a uniform environment for modelling, formal analysis, and design of discrete event systems. The main objective of this paper is to introduce the fundamental concepts of Petri Nets to the researchers and practitioners, both from identification systems, who are involved in the work in the areas of modelling and analysis of biometric identification types of systems, as well as those who may potentially be involved in these areas. In addition, the paper introduces high-level Petri Nets, as Colored Petri Nets (CPN). In this paper the model of Colored Petri Net describes the identification process much simpler.

Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt; Kristensen, Lars Michael

Coloured Petri Nets (CPN) is a graphical language for modelling and validating concurrent and distributed systems, and other systems in which concurrency plays a major role. The development of such systems is particularly challenging because of inherent intricacies like possible nondeterminism an...

Petri nets - part 1: concepts and application areas

International Nuclear Information System (INIS)

Sivertsen, Terje

2004-03-01

There exist a number of models, languages, methods, and tools that support the specification and analysis of system requirements. One important class comprises graphical methods based on the concept of Petri nets. Due to the wide variety of applications, these methods are relevant also in research and applications outside the digital systems safety domain. The present report constitutes the first of three parts of a unified exposition of graphical methods based on the concept of Petri nets. The report provides an introduction to basic concepts of Petri nets and an overview of a wide variety of application areas. The second part of the trilogy will present a number of techniques and tools. The third part will focus on analysis. Petri nets have been proposed for a wide variety of applications, and new areas are considered as new challenges emerge from scientific, technological, and social developments. The wide variety of application areas reflects a broad interest in Petri nets, coming from diverse directions. Empirically, as well as theoretically, there are good reasons to claim that Petri nets are applicable for many different kinds of problems. What is common to the different applications and problems addressed is the need for a formalism that allows adequate representation of important system characteristics like concurrency, asyncronicity, distribution, parallelism, and non-determinism. Several of the references in the report discuss NPP-related applications, or applications with great potentials for technology transfer from other areas to the nuclear domain. (Author)

The ePNK: An Extensible Petri Net Tool for PNML

DEFF Research Database (Denmark)

Kindler, Ekkart

2011-01-01

The Petri Net Markup Language (PNML) is an XML-based interchange format for all kinds of Petri nets, which is an ISO/IEC International Standard 15909-2 now. The focus of this standard is on PNML as an interchange format for high-level Petri nets. PNML, however, is more general and allows exchanging...

Transactions on Petri Nets and Other Models of Concurrency V

DEFF Research Database (Denmark)

submission track of ToPNoC. The 12 papers cover a diverse range of topics including model checking and system verification, synthesis, foundational work on specific classes of Petri nets, and innovative applications of Petri nets and other models of concurrency. Thus, this volume gives a good view of ongoing...... concurrent systems and Petri nets research...

Coloured Petri Nets

CERN Document Server

Jensen, Kurt

2009-01-01

Coloured Petri Nets (CPN) is a graphical language for modelling and validating concurrent and distributed systems, and other systems in which concurrency plays a major role. This book introduces the constructs of the CPN modelling language and presents the related analysis methods. It provides a comprehensive road map for the practical use of CPN.

Teaching Petri Nets Using P3

Science.gov (United States)

Gasevic, Dragan; Devedzic, Vladan

2004-01-01

This paper presents Petri net software tool P3 that is developed for training purposes of the Architecture and organization of computers (AOC) course. The P3 has the following features: graphical modeling interface, interactive simulation by single and parallel (with previous conflict resolution) transition firing, two well-known Petri net…

The application of Petri nets to failure analysis

International Nuclear Information System (INIS)

Liu, T.S.; Chiou, S.B.

1997-01-01

Unlike the technique of fault tree analysis that has been widely applied to system failure analysis in reliability engineering, this study presents a Petri net approach to failure analysis. It is essentially a graphical method for describing relations between conditions and events. The use of Petri nets in failure analysis enables to replace logic gate functions in fault trees, efficiently obtain minimal cut sets, and absorb models. It is demonstrated that for failure analysis Petri nets are more efficient than fault trees. In addition, this study devises an alternative; namely, a trapezoidal graph method in order to account for failure scenarios. Examples validate this novel method in dealing with failure analysis

Towards Self-Managed Executable Petri Nets

DEFF Research Database (Denmark)

Hansen, Klaus Marius; Zhang, Weishan; Ingstrup, Mads

2008-01-01

An issue in self-managed systems is that different abstractions and programming models are used on different architectural layers, leading to systems that are harder to build and understand. To alleviate this, we introduce a self-management approach which combines high-level Petri nets...... with the capability of distributed communication among nets. Organized in a three-layer goal management, change management, and component control architecture this allows for self-management in distributed systems. We validate the approach through the Flamenco/CPN middleware that allows for self-management of service......-oriented pervasive computing systems through the runtime interpretation of colored Petri nets. The current work focuses on the change management and component control layers....

Pragmatics Annotated Coloured Petri Nets for Protocol Software Generation and Verification

DEFF Research Database (Denmark)

Fagerland Simonsen, Kent Inge; Kristensen, Lars Michael; Kindler, Ekkart

2015-01-01

PetriCode is a tool that supports automated generation of protocol software from a restricted class of Coloured Petri Nets (CPNs) called Pragmatics Annotated Coloured Petri Nets (PA-CPNs). Petri-Code and PA-CPNs have been designed with five main requirements in mind, which include the same model...

Transactions on Petri Nets and Other Models of Concurrency VII

DEFF Research Database (Denmark)

The first section is concerned with the creation of Petri net models and their validation The second section addresses semantic issues and analysis methods The third section is devoted to the automatic synthesis of Petri nets These Transactions publish archival papers in the broad area of Petri n...

A simulator for high-level Petri nets: An ePNK application

DEFF Research Database (Denmark)

Kindler, Ekkart; Laganeckas, Mindaugas

2013-01-01

The ePNK is a platform for Petri net tools based on the PNML transfer format. One of its important features is its extensibility, which allows developers to plug in new Petri net types and new functions and applications for different kinds of Petri nets. The basic version of the ePNK provides...

Pragmatics annotated coloured petri nets for protocol software generation and verification

DEFF Research Database (Denmark)

Simonsen, Kent Inge Fagerland; Kristensen, Lars M.; Kindler, Ekkart

2016-01-01

Pragmatics Annotated Coloured Petri Nets (PA-CPNs) are a restricted class of Coloured Petri Nets (CPNs) developed to support automated generation of protocol software. The practical application of PA-CPNs and the supporting PetriCode software tool have been discussed and evaluated in earlier papers...

Petri nets SM-cover-based on heuristic coloring algorithm

Science.gov (United States)

Tkacz, Jacek; Doligalski, Michał

2015-09-01

In the paper, coloring heuristic algorithm of interpreted Petri nets is presented. Coloring is used to determine the State Machines (SM) subnets. The present algorithm reduces the Petri net in order to reduce the computational complexity and finds one of its possible State Machines cover. The proposed algorithm uses elements of interpretation of Petri nets. The obtained result may not be the best, but it is sufficient for use in rapid prototyping of logic controllers. Found SM-cover will be also used in the development of algorithms for decomposition, and modular synthesis and implementation of parallel logic controllers. Correctness developed heuristic algorithm was verified using Gentzen formal reasoning system.

Requirements and Evaluation of tool papers for PETRI NETS

DEFF Research Database (Denmark)

Franceschinis, Giuliana; van Hee, Kees; Kindler, Ekkart

2008-01-01

This paper gives guidelines for the publication of papers on software tools, in particular for Petri net tools. The guidelines are illustrated by an example.......This paper gives guidelines for the publication of papers on software tools, in particular for Petri net tools. The guidelines are illustrated by an example....

PNet: A Python Library for Petri Net Modeling and Simulation

OpenAIRE

Zhu En Chay; Bing Feng Goh; Maurice HT Ling

2016-01-01

Petri Net is a formalism to describe changes between 2 or more states across discrete time and has been used to model many systems. We present PNet – a pure Python library for Petri Net modeling and simulation in Python programming language. The design of PNet focuses on reducing the learning curve needed to define a Petri Net by using a text-based language rather than programming constructs to define transition rules. Complex transition rules can be refined as regular Python functions. To de...

Computer Tools for Construction, Modification and Analysis of Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1987-01-01

The practical use of Petri nets is — just as any other description technique — very dependent on the existence of adequate computer tools, which may assist the user to cope with the many details of a large description. For Petri nets there is a need for tools supporting construction of nets...

Pragmatics Annotated Coloured Petri Nets for Protocol Software Generation and Verification

DEFF Research Database (Denmark)

Simonsen, Kent Inge; Kristensen, Lars Michael; Kindler, Ekkart

This paper presents the formal definition of Pragmatics Annotated Coloured Petri Nets (PA-CPNs). PA-CPNs represent a class of Coloured Petri Nets (CPNs) that are designed to support automated code genera-tion of protocol software. PA-CPNs restrict the structure of CPN models and allow Petri net...... elements to be annotated with so-called pragmatics, which are exploited for code generation. The approach and tool for gen-erating code is called PetriCode and has been discussed and evaluated in earlier work already. The contribution of this paper is to give a formal def-inition for PA-CPNs; in addition...

Petri Net Modeling of Computer Virus Life Cycle | Ikekonwu ...

African Journals Online (AJOL)

Virus life cycle, which refers to the stages of development of a computer virus, is presented as a suitable area for the application of Petri nets. Petri nets a powerful modeling tool in the field of dynamic system analysis is applied to model the virus life cycle. Simulation of the derived model is also presented. The intention of ...

Annotating Coloured Petri Nets

DEFF Research Database (Denmark)

Lindstrøm, Bo; Wells, Lisa Marie

2002-01-01

Coloured Petri nets (CP-nets) can be used for several fundamentally different purposes like functional analysis, performance analysis, and visualisation. To be able to use the corresponding tool extensions and libraries it is sometimes necessary to include extra auxiliary information in the CP......-net. An example of such auxiliary information is a counter which is associated with a token to be able to do performance analysis. Modifying colour sets and arc inscriptions in a CP-net to support a specific use may lead to creation of several slightly different CP-nets – only to support the different uses...... of the same basic CP-net. One solution to this problem is that the auxiliary information is not integrated into colour sets and arc inscriptions of a CP-net, but is kept separately. This makes it easy to disable this auxiliary information if a CP-net is to be used for another purpose. This paper proposes...

Fault Diagnosis System of Wind Turbine Generator Based on Petri Net

Science.gov (United States)

Zhang, Han

Petri net is an important tool for discrete event dynamic systems modeling and analysis. And it has great ability to handle concurrent phenomena and non-deterministic phenomena. Currently Petri nets used in wind turbine fault diagnosis have not participated in the actual system. This article will combine the existing fuzzy Petri net algorithms; build wind turbine control system simulation based on Siemens S7-1200 PLC, while making matlab gui interface for migration of the system to different platforms.

A Method of Sample Models of Program Construction in Terms of Petri Nets

Directory of Open Access Journals (Sweden)

D. I. Kharitonov

2015-01-01

Full Text Available In the article a method of automated construction of Petri nets simulating the behaviour of imperative programs is considered from the formal point of view. Petri net samples with certain characteristics are necessary in programming new algorithms for program analysis; in particular, they can be used for developing or optimizing algorithms of Petri nets compositions and decompositions, building the reachability tree, checking invariants and so on. The generation process consists of two stages. At the first stage, construction templates for a resulting net and parameters for construction are described. With the help of these parameters it is possible to regulate the final size and the absolute or relative amount of certain structures in the resulting net. At the second stage, iterative process of automated net construction is used for Petri net generation of any size, limited only by an available computer memory. In the first section of the article the minimum necessary definitions are given and a new version of Petri nets composition operation by places is introduced. Commutative and associative properties of introduced binary operation allow to synchronize any number of Petri nets in arbitrary order. Then construction template is defined as a marked Petri net with input and output interfaces and rules for templates composition using this interfaces. A number of construction templates can be united in a collection, for which the evolution rules are defined. The completeness property of a collection guarantees that the collection evolution results in a Petri net that simulates the imperative program behavior. The article provides a version of the construction templates complete collection and an example of Petri net simulating sequential imperative program construction.

State Space Methods for Timed Petri Nets

DEFF Research Database (Denmark)

Christensen, Søren; Jensen, Kurt; Mailund, Thomas

2001-01-01

it possible to condense the usually infinite state space of a timed Petri net into a finite condensed state space without loosing analysis power. The second method supports on-the-fly verification of certain safety properties of timed systems. We discuss the application of the two methods in a number......We present two recently developed state space methods for timed Petri nets. The two methods reconciles state space methods and time concepts based on the introduction of a global clock and associating time stamps to tokens. The first method is based on an equivalence relation on states which makes...

A Forward Reachability Algorithm for Bounded Timed-Arc Petri Nets

DEFF Research Database (Denmark)

David, Alexandre; Jacobsen, Lasse; Jacobsen, Morten

2012-01-01

Timed-arc Petri nets (TAPN) are a well-known time extension of thePetri net model and several translations to networks of timedautomata have been proposed for this model.We present a direct, DBM-basedalgorithm for forward reachability analysis of bounded TAPNs extended with transport arcs...

Automatic pipeline operation using Petri Nets

Energy Technology Data Exchange (ETDEWEB)

Moreira, Guilherme O. [PETROBRAS TRANSPORTE S.A., Rio de Janeiro, RJ (Brazil)

2009-07-01

A pipeline operation requires several actions, attention and time from the control room operator in each of its operating phases. This article proposition is to use automation as something more than a remote control, drastically reducing the number of repetitive and routine actions needed from the operator to start and stop the system, granting more time for system supervision, decision making during critical conditions and avoiding errors caused due to the need of several actions being executed in a short period of time. To achieve these objectives the pipeline operation will be modeled as a Petri Net consisting of states, event and actions. A methodology for converting this Petri Net into a Ladder controller code will also be proposed. (author)

CPN Tools for Editing, Simulating, and Analysing Coloured Petri Nets

DEFF Research Database (Denmark)

Ratzer, Anne Vinter; Wells, Lisa Marie; Lassen, Henry Michael

2003-01-01

CPN Tools is a tool for editing, simulating and analysing Coloured Petri Nets. The GUI is based on advanced interaction techniques, such as toolglasses, marking menus, and bi-manual interaction. Feedback facilities provide contextual error messages and indicate dependency relationships between ne...... information such as boundedness properties and liveness properties. The functionality of the simulation engine and state space facilities are similar to the corresponding components in Design/CPN, which is a widespread tool for Coloured Petri Nets.......CPN Tools is a tool for editing, simulating and analysing Coloured Petri Nets. The GUI is based on advanced interaction techniques, such as toolglasses, marking menus, and bi-manual interaction. Feedback facilities provide contextual error messages and indicate dependency relationships between net...

A Brief Introduction to Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1997-01-01

Coloured Petri Nets (CP-nets or CPN) is a graphical oriented language for design, specification, simulation and verification of systems. It is in particular well- suited for systems in which communication, synchronisation and resource sharing are important. Typical examples of application areas a...

Performance Analysis using Coloured Petri Nets

DEFF Research Database (Denmark)

Wells, Lisa Marie

Performance is often a central issue in the design, development, and configuration of systems. It is not always enough to know that systems work properly, they must also work effectively. There are numerous studies, e.g. in the areas of computer and telecommunication systems, manufacturing......, military, health care, and transportation, that have shown that time, money, and even lives can be saved if the performance of a system is improved. Performance analysis studies are conducted to evaluate existing or planned systems, to compare alternative configurations, or to find an optimal configuration...... of a system. There are three alternative techniques for analysing the performance of a system: measurement, analytical models, and simulation models. This dissertation focuses on the the use of coloured Petri nets for simulationbased performance analysis of industrial-sized systems. Coloured Petri nets...

Dependencies in event trees analyzed by Petri nets

International Nuclear Information System (INIS)

Nývlt, Ondřej; Rausand, Marvin

2012-01-01

This paper discusses how non-marked Petri nets can be used to model and analyze event trees where the pivotal (branching) events are dependent and modeled by fault trees. The dependencies may, for example, be caused by shared utilities, shared components, or general common cause failures that are modeled by beta-factor models. These dependencies are cumbersome to take into account when using standard event-/fault tree modeling techniques, and may lead to significant errors in the calculated end-state probabilities of the event tree if they are not properly analyzed. A new approach is proposed in this paper, where the whole event tree is modeled by a non-marked Petri net and where P-invariants, representing the structural properties of the Petri net, are used to obtain the frequency of each end-state of the event tree with dependencies. The new approach is applied to a real example of an event tree analysis of the Strahov highway tunnel in Prague, Czech Republic, including two types of dependencies (shared Programmable Logic Controllers and Common Cause Failures). - Highlights: ► In this paper, we model and analyze event trees (ET) using Petri nets. ► The pivotal events of the modeled event trees are dependent (e.g., shared PLCs, CCF). ► A new method based on P-invariants to obtain probabilities of end states is proposed. ► Method is shown in the case study of the Stahov tunnel in the Czech Republic.

A Generalised Approach to Petri Nets and Algebraic Specifications

International Nuclear Information System (INIS)

Sivertsen, Terje

1998-02-01

The present report represents a continuation of the work on Petri nets and algebraic specifications. The reported research has focused on generalising the approach introduced in HWR-454, with the aim of facilitating the translation of a wider class of Petri nets into algebraic specification. This includes autonomous Petri nets with increased descriptive power, as well as non-autonomous Petri nets allowing the modelling of systems (1) involving extensive data processing; (2) with transitions synchronized on external events; (3) whose evolutions are time dependent. The generalised approach has the important property of being modular in the sense that the translated specifications can be gradually extended to include data processing, synchronization, and timing. The report also discusses the relative merits of state-based and transition-based specifications, and includes a non-trivial case study involving automated proofs of a large number of interrelated theorems. The examples in the report illustrate the use of the new HRP Prover. Of particular importance in this context is the automatic transformation between state-based and transitionbased specifications. It is expected that the approach introduced in HWR-454 and generalised in the present report will prove useful in future work on combination of wide variety of specification techniques

Modeling of water treatment plant using timed continuous Petri nets

Science.gov (United States)

Nurul Fuady Adhalia, H.; Subiono, Adzkiya, Dieky

2017-08-01

Petri nets represent graphically certain conditions and rules. In this paper, we construct a model of the Water Treatment Plant (WTP) using timed continuous Petri nets. Specifically, we consider that (1) the water pump always active and (2) the water source is always available. After obtaining the model, the flow through the transitions and token conservation laws are calculated.

Reachability Trees for High-level Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt; Jensen, Arne M.; Jepsen, Leif Obel

1986-01-01

the necessary analysis methods. In other papers it is shown how to generalize the concept of place- and transition invariants from place/transition nets to high-level Petri nets. Our present paper contributes to this with a generalization of reachability trees, which is one of the other important analysis...

Application of Coloured Petri Nets in System Development

DEFF Research Database (Denmark)

Kristensen, Lars Michael; Jørgensen, Jens Bæk; Jensen, Kurt

2004-01-01

Coloured Petri Nets (CP-nets or CPNs) and their supporting computer tools have been used in a wide range of application areas such as communication protocols, software designs, and embedded systems. The practical application of CP-nets has also covered many phases of system development ranging fr...

Coloured Petri Nets and CPN Tools for Modelling and Validation of Concurrent Systems

DEFF Research Database (Denmark)

Jensen, Kurt; Kristensen, Lars Michael; Wells, Lisa Marie

2007-01-01

Coloured Petri Nets (CPNs) is a language for the modeling and validation og systems in which concurrency, communication, and synchronisation play a major role. Coloured Petri Nets is a descrete-event modeling language combining Petri Nets with the funcitonal programming language Standard ML. Petr...... with user-defined Standard ML functions. A license for CPN Tools can be obtained free of charge, also for commercial use....

Petri Nets in Cryptographic Protocols

DEFF Research Database (Denmark)

Crazzolara, Federico; Winskel, Glynn

2001-01-01

A process language for security protocols is presented together with a semantics in terms of sets of events. The denotation of process is a set of events, and as each event specifies a set of pre and postconditions, this denotation can be viewed as a Petri net. By means of an example we illustrate...

Accurate Complex Systems Design: Integrating Serious Games with Petri Nets

Directory of Open Access Journals (Sweden)

Kirsten Sinclair

2016-03-01

Full Text Available Difficulty understanding the large number of interactions involved in complex systems makes their successful engineering a problem. Petri Nets are one graphical modelling technique used to describe and check proposed designs of complex systems thoroughly. While automatic analysis capabilities of Petri Nets are useful, their visual form is less so, particularly for communicating the design they represent. In engineering projects, this can lead to a gap in communications between people with different areas of expertise, negatively impacting achieving accurate designs.In contrast, although capable of representing a variety of real and imaginary objects effectively, behaviour of serious games can only be analysed manually through interactive simulation. This paper examines combining the complementary strengths of Petri Nets and serious games. The novel contribution of this work is a serious game prototype of a complex system design that has been checked thoroughly. Underpinned by Petri Net analysis, the serious game can be used as a high-level interface to communicate and refine the design.Improvement of a complex system design is demonstrated by applying the integration to a proof-of-concept case study.   

Characterizing behavioural congruences for Petri nets

DEFF Research Database (Denmark)

Nielsen, Mogens; Priese, Lutz; Sassone, Vladimiro

1995-01-01

We exploit a notion of interface for Petri nets in order to design a set of net combinators. For such a calculus of nets, we focus on the behavioural congruences arising from four simple notions of behaviour, viz., traces, maximal traces, step, and maximal step traces, and from the corresponding...... four notions of bisimulation, viz., weak and weak step bisimulation and their maximal versions. We characterize such congruences via universal contexts and via games, providing in such a way an understanding of their discerning powers....

An Efficient Translation of Timed-Arc Petri Nets to Networks of Timed Automata

DEFF Research Database (Denmark)

Byg, Joakim; Jørgensen, Kenneth Yrke; Srba, Jiri

2009-01-01

Bounded timed-arc Petri nets with read-arcs were recently proven equivalent to networks of timed automata, though the Petri net model cannot express urgent behaviour and the described mutual trans- lations are rather inefficient. We propose an extension of timed-arc Petri nets with invariants...... to enforce urgency and with transport arcs to generalise the read-arcs. We also describe a novel translation from the extended timed-arc Petri net model to networks of timed automata. The translation is implemented in the tool TAPAAL and it uses UPPAAL as the verification engine. Our experiments confirm...... the efficiency of the translation and in some cases the translated models verify significantly faster than the native UPPAAL models do....

A Method to Compare the Descriptive Power of Different Types of Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1980-01-01

The purpose of this paper is to show how the descriptive power of different types of Petri nets can be compared, without the use of Petri net languages. Moreover the paper proposes an extension of condition/event-nets and it is shown that this extension has the same descriptive power as condition/event-nets....

Distributed evaluation of stochastic Petri nets

NARCIS (Netherlands)

Bell, A.; Buchholz, Peter; Lehnert, Ralf; Pioro, Micha

2004-01-01

In this paper we present on the distributed performance evaluation and model checking of systems specified by stochastic Petri nets. The approaches discussed rely on an explicit state-space generation and target at the usage of clusters of workstations. We present results for systems with several

Verification of Timed-Arc Petri Nets

DEFF Research Database (Denmark)

Jacobsen, Lasse; Jacobsen, Morten; Møller, Mikael Harkjær

2011-01-01

of interesting theoretical properties distinguishing them from other time extensions of Petri nets. We shall give an overview of the recent theory developed in the verification of TAPN extended with features like read/transport arcs, timed inhibitor arcs and age invariants. We will examine in detail...

Using UML and Petri nets for visualization of business document flow

Directory of Open Access Journals (Sweden)

Ivana Rábová

2012-01-01

Full Text Available The article deals with two principles of business workflow modeling, Petri nets and UML notation, that are the acceptable approaches to business modeling and can be used also for business documents workflow. The special type of Petri nets, WF-nets and UML activity diagrams are used in this article and both modeling ways are presented on the concrete business workflow and then there are presented and specified their advantage and disadvantage for business documents flows. At beginning it is explained the word workflow in context business documents, its features, principles and using in business environment. After that it is clarified that the UML is OMG’s most-used specification, and the way the world models not only application structure, behavior, and architecture, but also business process, workflows and data structure. Activity diagram UML is good way to show how different workflows in the business are managed, how they start, go and stop. Diagrams also show many different decision paths that can be taken from start to finish. State charts can be used as a detail the transitions or changes of states when documents can go through in the business. They show how a documents moves from one state to another and the rules that govern that change. Petri-nets offer a graphical notation for stepwise processes that include choice, iteration, and concurrent execution. Unlike UML Petri nets have an exact mathematical definition of their execution semantics, with a well-developed mathematical theory for process analysis. In the article there are modeled a special type of Petri nets, the WF-nets. The practical part of article incorporates two models of concrete business documents workflows presented in these notations, their comparison and recommendation for using these diagrams in business process management.

A primer on the Petri Net Markup Language and ISO/IEC 15909-2

DEFF Research Database (Denmark)

Hillah, L. M.; Kindler, Ekkart; Kordon, F.

2009-01-01

Standard, defines a transfer format for high-level nets. The transfer format defined in Part 2 of ISO/IEC 15909 is (or is based on) the \\emph{Petri Net Markup Language} (PNML), which was originally introduced as an interchange format for different kinds of Petri nets. In ISO/IEC 15909-2, however...

Reliability modelling of repairable systems using Petri nets and fuzzy Lambda-Tau methodology

International Nuclear Information System (INIS)

Knezevic, J.; Odoom, E.R.

2001-01-01

A methodology is developed which uses Petri nets instead of the fault tree methodology and solves for reliability indices utilising fuzzy Lambda-Tau method. Fuzzy set theory is used for representing the failure rate and repair time instead of the classical (crisp) set theory because fuzzy numbers allow expert opinions, linguistic variables, operating conditions, uncertainty and imprecision in reliability information to be incorporated into the system model. Petri nets are used because unlike the fault tree methodology, the use of Petri nets allows efficient simultaneous generation of minimal cut and path sets

Modelling of Biometric Identification System with Given Parameters Using Colored Petri Nets

Science.gov (United States)

Petrosyan, G.; Ter-Vardanyan, L.; Gaboutchian, A.

2017-05-01

Biometric identification systems use given parameters and function on the basis of Colored Petri Nets as a modelling language developed for systems in which communication, synchronization and distributed resources play an important role. Colored Petri Nets combine the strengths of Classical Petri Nets with the power of a high-level programming language. Coloured Petri Nets have both, formal intuitive and graphical presentations. Graphical CPN model consists of a set of interacting modules which include a network of places, transitions and arcs. Mathematical representation has a well-defined syntax and semantics, as well as defines system behavioural properties. One of the best known features used in biometric is the human finger print pattern. During the last decade other human features have become of interest, such as iris-based or face recognition. The objective of this paper is to introduce the fundamental concepts of Petri Nets in relation to tooth shape analysis. Biometric identification systems functioning has two phases: data enrollment phase and identification phase. During the data enrollment phase images of teeth are added to database. This record contains enrollment data as a noisy version of the biometrical data corresponding to the individual. During the identification phase an unknown individual is observed again and is compared to the enrollment data in the database and then system estimates the individual. The purpose of modeling biometric identification system by means of Petri Nets is to reveal the following aspects of the functioning model: the efficiency of the model, behavior of the model, mistakes and accidents in the model, feasibility of the model simplification or substitution of its separate components for more effective components without interfering system functioning. The results of biometric identification system modeling and evaluating are presented and discussed.

Complex accident scenarios modelled and analysed by Stochastic Petri Nets

International Nuclear Information System (INIS)

Nývlt, Ondřej; Haugen, Stein; Ferkl, Lukáš

2015-01-01

This paper is focused on the usage of Petri nets for an effective modelling and simulation of complicated accident scenarios, where an order of events can vary and some events may occur anywhere in an event chain. These cases are hardly manageable by traditional methods as event trees – e.g. one pivotal event must be often inserted several times into one branch of the tree. Our approach is based on Stochastic Petri Nets with Predicates and Assertions and on an idea, which comes from the area of Programmable Logic Controllers: an accidental scenario is described as a net of interconnected blocks, which represent parts of the scenario. So the scenario is firstly divided into parts, which are then modelled by Petri nets. Every block can be easily interconnected with other blocks by input/output variables to create complex ones. In the presented approach, every event or a part of a scenario is modelled only once, independently on a number of its occurrences in the scenario. The final model is much more transparent then the corresponding event tree. The method is shown in two case studies, where the advanced one contains a dynamic behavior. - Highlights: • Event & Fault trees have problems with scenarios where an order of events can vary. • Paper presents a method for modelling and analysis of dynamic accident scenarios. • The presented method is based on Petri nets. • The proposed method solves mentioned problems of traditional approaches. • The method is shown in two case studies: simple and advanced (with dynamic behavior)

Necessary and sufficient liveness condition of GS3PR Petri nets

Science.gov (United States)

Liu, GaiYun; Barkaoui, Kamel

2015-05-01

Structural analysis is one of the most important and efficient methods to investigate the behaviour of Petri nets. Liveness is a significant behavioural property of Petri nets. Siphons, as structural objects of a Petri net, are closely related to its liveness. Many deadlock control policies for flexible manufacturing systems (FMS) modelled by Petri nets are implemented via siphon control. Most of the existing methods design liveness-enforcing supervisors by adding control places for siphons based on their controllability conditions. To compute a liveness-enforcing supervisor with as much as permissive behaviour, it is both theoretically and practically significant to find an exact controllability condition for siphons. However, the existing conditions, max, max‧, and max″-controllability of siphons are all overly restrictive and generally sufficient only. This paper develops a new condition called max*-controllability of the siphons in generalised systems of simple sequential processes with resources (GS3PR), which are a net subclass that can model many real-world automated manufacturing systems. We show that a GS3PR is live if all its strict minimal siphons (SMS) are max*-controlled. Compared with the existing conditions, i.e., max-, max‧-, and max″-controllability of siphons, max*-controllability of the SMS is not only sufficient but also necessary. An example is used to illustrate the proposed method.

Modeling biological gradient formation: combining partial differential equations and Petri nets.

Science.gov (United States)

Bertens, Laura M F; Kleijn, Jetty; Hille, Sander C; Heiner, Monika; Koutny, Maciej; Verbeek, Fons J

2016-01-01

Both Petri nets and differential equations are important modeling tools for biological processes. In this paper we demonstrate how these two modeling techniques can be combined to describe biological gradient formation. Parameters derived from partial differential equation describing the process of gradient formation are incorporated in an abstract Petri net model. The quantitative aspects of the resulting model are validated through a case study of gradient formation in the fruit fly.

Time Extensions of Petri Nets for Modelling and Verification of Hard Real-Time Systems

Directory of Open Access Journals (Sweden)

Tomasz Szmuc

2002-01-01

Full Text Available The main aim ofthe paper is a presentation of time extensions of Petri nets appropriate for modelling and analysis of hard real-time systems. It is assumed, that the extensions must provide a model of time flow an ability to force a transition to fire within a stated timing constraint (the so-called the strong firing rule, and timing constraints represented by intervals. The presented survey includes extensions of classical Place/Transition Petri nets, as well as the ones applied to high-level Petri nets. An expressiveness of each time extension is illustrated using simple hard real-time system. The paper includes also a brief description of analysis and veryication methods related to the extensions, and a survey of software tools supporting modelling and analysis ofthe considered Petri nets.

Workshop on Practical Use of Coloured Petri Nets and Design/CPN

DEFF Research Database (Denmark)

This booklet contains the proceedings of the 1998 Workshop on Practical use of Coloured Petri Nets and Design/CPN. The papers are also available in electronic form via the CPN Web pages at University of Aarhus.......This booklet contains the proceedings of the 1998 Workshop on Practical use of Coloured Petri Nets and Design/CPN. The papers are also available in electronic form via the CPN Web pages at University of Aarhus....

Control of Petri Nets by finite automata

Energy Technology Data Exchange (ETDEWEB)

Burkhard, H D

1983-01-01

Petri Nets are considered where the firings are controlled by finite automata. The control may be distributed to various automata working over disjoint sets of transitions. To avoid deadlocks and conflicts for the whole system the distribution of control must be organised in an appropriate manner. The existence of deadlocks and conflicts is shown to be undecidable in general, but conflict resolving and deadlock free controls can be constructed for given nets. 10 references.

Software Design Modelling with Functional Petri Nets | Bakpo ...

African Journals Online (AJOL)

Software Design Modelling with Functional Petri Nets. ... of structured programs and a FPN Software prototype proposed for the conventional programming construct: if-then-else statement. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

Automation of Presentation Record Production Based on Rich-Media Technology Using SNT Petri Nets Theory

Directory of Open Access Journals (Sweden)

Ivo Martiník

2015-01-01

Full Text Available Rich-media describes a broad range of digital interactive media that is increasingly used in the Internet and also in the support of education. Last year, a special pilot audiovisual lecture room was built as a part of the MERLINGO (MEdia-rich Repository of LearnING Objects project solution. It contains all the elements of the modern lecture room determined for the implementation of presentation recordings based on the rich-media technologies and their publication online or on-demand featuring the access of all its elements in the automated mode including automatic editing. Property-preserving Petri net process algebras (PPPA were designed for the specification and verification of the Petri net processes. PPPA does not need to verify the composition of the Petri net processes because all their algebraic operators preserve the specified set of the properties. These original PPPA are significantly generalized for the newly introduced class of the SNT Petri process and agent nets in this paper. The PLACE-SUBST and ASYNC-PROC algebraic operators are defined for this class of Petri nets and their chosen properties are proved. The SNT Petri process and agent nets theory were significantly applied at the design, verification, and implementation of the programming system ensuring the pilot audiovisual lecture room functionality.

How to Find Invariants for Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1981-01-01

This paper shows how invariants can be found for coloured Petri Nets. We define a set of transformation rules, which can be used to transform the incidence matrix, without changing the set of invariants....

Petri Nets as Models of Linear Logic

DEFF Research Database (Denmark)

Engberg, Uffe Henrik; Winskel, Glynn

1990-01-01

The chief purpose of this paper is to appraise the feasibility of Girad's linear logic as a specification language for parallel processes. To this end we propose an interpretation of linear logic in Petri nets, with respect to which we investigate the expressive power of the logic...

Determinization of timed Petri nets behaviors

Czech Academy of Sciences Publication Activity Database

Komenda, Jan; Lahaye, S.; Boimond, J.-L.

2016-01-01

Roč. 26, č. 3 (2016), s. 413-437 ISSN 0924-6703 R&D Projects: GA MŠk LH13012; GA ČR GA15-02532S Institutional support: RVO:67985840 Keywords : timed Petri nets * (max,+) automata * determinization Subject RIV: BA - General Mathematics Impact factor: 1.660, year: 2016 http://link.springer.com/article/10.1007%2Fs10626-015-0214-1

PETRI NET MODELING OF COMPUTER VIRUS LIFE CYCLE

African Journals Online (AJOL)

Dr Obe

dynamic system analysis is applied to model the virus life cycle. Simulation of the derived model ... Keywords: Virus lifecycle, Petri nets, modeling. simulation. .... complex process. Figure 2 .... by creating Matlab files for five different computer ...

Diagnostic system based on condition turbogenerator Petri nets

International Nuclear Information System (INIS)

Kachur, S.A.; Shakhova, N.V.

2016-01-01

A stochastic model of the automated monitoring systems and process control turbine generator based on Petri nets, allowing to detect local changes in the state of the stator windings of turbogenerator, is presented in the paper [ru

The  Practitioner's guide to Coloured Petri Nets

DEFF Research Database (Denmark)

Kristensen, Lars Michael; Christensen, Søren; Jensen, Kurt

1998-01-01

four hundred commercial companies. It is available free of charge, also for commercial use. This paper provides a comprehensive road map to the practical use of CP-nets and the Design/CPN tool. We give an informal introduction to the basic concepts and ideas underliying CP-nets. The key components...... and facilities of the Design/CPN tool are presented and their use illustrated. The paper is self-contained and does not assume any prior kowledge of Petri nets and CP-nets nor any experience with the Design/CPN tool...

Knowledge base verification based on enhanced colored petri net

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Hyun; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1998-12-31

Verification is a process aimed at demonstrating whether a system meets it`s specified requirements. As expert systems are used in various applications, the knowledge base verification of systems takes an important position. The conventional Petri net approach that has been studied recently in order to verify the knowledge base is found that it is inadequate to verify the knowledge base of large and complex system, such as alarm processing system of nuclear power plant. Thus, we propose an improved method that models the knowledge base as enhanced colored Petri net. In this study, we analyze the reachability and the error characteristics of the knowledge base and apply the method to verification of simple knowledge base. 8 refs., 4 figs. (Author)

Knowledge base verification based on enhanced colored petri net

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Hyun; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1997-12-31

Verification is a process aimed at demonstrating whether a system meets it`s specified requirements. As expert systems are used in various applications, the knowledge base verification of systems takes an important position. The conventional Petri net approach that has been studied recently in order to verify the knowledge base is found that it is inadequate to verify the knowledge base of large and complex system, such as alarm processing system of nuclear power plant. Thus, we propose an improved method that models the knowledge base as enhanced colored Petri net. In this study, we analyze the reachability and the error characteristics of the knowledge base and apply the method to verification of simple knowledge base. 8 refs., 4 figs. (Author)

Reachability analysis of real-time systems using time Petri nets.

Science.gov (United States)

Wang, J; Deng, Y; Xu, G

2000-01-01

Time Petri nets (TPNs) are a popular Petri net model for specification and verification of real-time systems. A fundamental and most widely applied method for analyzing Petri nets is reachability analysis. The existing technique for reachability analysis of TPNs, however, is not suitable for timing property verification because one cannot derive end-to-end delay in task execution, an important issue for time-critical systems, from the reachability tree constructed using the technique. In this paper, we present a new reachability based analysis technique for TPNs for timing property analysis and verification that effectively addresses the problem. Our technique is based on a concept called clock-stamped state class (CS-class). With the reachability tree generated based on CS-classes, we can directly compute the end-to-end time delay in task execution. Moreover, a CS-class can be uniquely mapped to a traditional state class based on which the conventional reachability tree is constructed. Therefore, our CS-class-based analysis technique is more general than the existing technique. We show how to apply this technique to timing property verification of the TPN model of a command and control (C2) system.

Completeness Results for Linear Logic on Petri Nets

DEFF Research Database (Denmark)

Engberg, Uffe Henrik; Winskel, Glynn

1993-01-01

Completeness is shown for several versions of Girard's linear logic with respect to Petri nets as the class of models. The strongest logic considered is intuitionistic linear logic, with $otimes$, $-!circ$, &, $oplus$ and the exponential ! (''of course´´), and forms of quantification. This logic ...

Design of River System Deadlock Avoidance Supervisor by Using Petri Net

Directory of Open Access Journals (Sweden)

Danko Kezić

2010-05-01

Full Text Available Advanced function of the computer-based river traffic management system should automatically predict and prevent possible conflict and deadlock states between vessels by using adequate control policy (supervisor. This paper proposes a formal method for calculating maximally permissive deadlock prevention supervisor. To model the river system, the authors use a class of Petri net suitable for describing multiple re-entrant flowlines with disjoint sets of resources, jobs and control places, and matrix-based formal method to analyze the system. By using matrix algebra, the structural characteristics of the Petri net (circular waits, P-invariants, critical siphons and subsystem, key resource have been analyzed and the steps for supervisor design proposed. The first and the second level deadlocks can be avoided by maintaining the number of tokens in the critical subsystems and ensuring that the key resource would not be the last available resource in the system. The derived supervisor has been verified by a computer simulation using MATLAB environment. KEYWORDS: traffic management system, deadlock avoidance, discrete event system, Petri net

Ninth Workshop and Tutorial on Practical Use of Coloured Petri Nets and the CPN Tools

DEFF Research Database (Denmark)

Daniel Moldt, Gremany Laure Petrucci, France Rüdiger Vlak, Germany Lee Wagenhals, USA Karsten Wolf, Germany Jianli Xu, Finland The programme committee has accepted 10 papers for presentation. Most of these deal with different projects in which Coloured Petri Nets and their tools have been put......This booklet contains the proceedings of the Ninth Workshop on Pratical Use of Coloured Petri Nets and CPN Tools, October 20-22, 2008. The workshop is organised by the CPN group at the Department of Computer Science, Aarhus University, Denmark. Coloured Petri Nets and the CPN Tools are now licensed...... to more than 7,200 users in 138 countries. The aim of the workshop is to bring together some of the users and in this way provide a forum for those who are interested in the practical use of Coloured Petri nets and their tools. The submitted papers were evaluated by a programme committee...

State Space Analysis of Hierarchical Coloured Petri Nets

DEFF Research Database (Denmark)

Christensen, Søren; Kristensen, Lars Michael

2003-01-01

In this paper, we consider state space analysis of Coloured Petri Nets. It is well-known that almost all dynamic properties of the considered system can be verified when the state space is finite. However, state space analysis is more than just formulating a set of formal requirements and invokin...... supporting computation and storage of state spaces which exploi the hierarchical structure of the models....... in which formal verification, partial state spaces, and analysis by means of graphical feedback and simulation are integrated entities. The focus of the paper is twofold: the support for graphical feedback and the way it has been integrated with simulation, and the underlying algorithms and data-structures......In this paper, we consider state space analysis of Coloured Petri Nets. It is well-known that almost all dynamic properties of the considered system can be verified when the state space is finite. However, state space analysis is more than just formulating a set of formal requirements and invoking...

Applying Petri nets in modelling the human factor

International Nuclear Information System (INIS)

Bedreaga, Luminita; Constntinescu, Cristina; Guzun, Basarab

2007-01-01

Usually, in the reliability analysis performed for complex systems, we determine the success probability to work with other performance indices, i.e. the likelihood associated with a given state. The possible values assigned to system states can be derived using inductive methods. If one wants to calculate the probability to occur a particular event in the system, then deductive methods should be applied. In the particular case of the human reliability analysis, as part of probabilistic safety analysis, the international regulatory commission have developed specific guides and procedures to perform such assessments. The paper presents the modality to obtain the human reliability quantification using the Petri nets approach. This is an efficient means to assess reliability systems because of their specific features. The examples showed in the paper are from human reliability documentation without a detailed human factor analysis (qualitative). We present human action modelling using event trees and Petri nets approach. The obtained results by these two kinds of methods are in good concordance. (authors)

METHOD OF DISPLAYING AN EXECUTABLE BUSINESS PROCESS MODELS INTO PETRI NETS

Directory of Open Access Journals (Sweden)

Igor G. Fedorov

2013-01-01

Full Text Available Executable business process models, as well as programs, require evidence of a defect-free finish. The methods based on the formalism of Petri nets are widely used. A business process is a network of dishes, and its properties are set by the analysis of the properties of the network. The aim is to study the methods of displaying an executable business process model in a Petri net. Analysis of the properties of the resulting model allows us to prove a number of important properties: it is a network of free choice and clean without looping.

Modeling and Simulation of Multi-scale Environmental Systems with Generalized Hybrid Petri Nets

Directory of Open Access Journals (Sweden)

Mostafa eHerajy

2015-07-01

Full Text Available Predicting and studying the dynamics and properties of environmental systems necessitates the construction and simulation of mathematical models entailing different levels of complexities. Such type of computational experiments often require the combination of discrete and continuous variables as well as processes operating at different time scales. Furthermore, the iterative steps of constructing and analyzing environmental models might involve researchers with different background. Hybrid Petri nets may contribute in overcoming such challenges as they facilitate the implementation of systems integrating discrete and continuous dynamics. Additionally, the visual depiction of model components will inevitably help to bridge the gap between scientists with distinct expertise working on the same problem. Thus, modeling environmental systems with hybrid Petri nets enables the construction of complex processes while keeping the models comprehensible for researchers working on the same project with significantly divergent education path. In this paper we propose the utilization of a special class of hybrid Petri nets, Generalized Hybrid Petri Nets (GHPN, to model and simulate environmental systems exposing processes interacting at different time-scales. GHPN integrate stochastic and deterministic semantics as well as other types of special basic events. Moreover, a case study is presented to illustrate the use of GHPN in constructing and simulating multi-timescale environmental scenarios.

Marine Traffic Optimization Using Petri Net and Genetic Algorithm

Directory of Open Access Journals (Sweden)

Anita Gudelj

2012-11-01

Full Text Available The paper deals with the traffic control and job optimization in the marine canal system. The moving of vessels can be described as a set of discrete events and states. Some of these states can be undesirable such as conflicts and deadlocks. It is necessary to apply adequate control policy to avoid deadlocks and blocks the vessels’ moving only in the case of dangerous situation. This paper addresses the use of Petri net as modelling and scheduling tool in this context. To find better solutions the authors propose the integration of Petri net with a genetic algorithm. Also, a matrix based formal method is proposed for analyzing discrete event dynamic system (DEDS. The algorithm is developed to deal with multi-project, multi-constrained scheduling problem with shared resources. It is verified by a computer simulation using MATLAB environment.

CSL model checking of deterministic and stochastic Petri nets

NARCIS (Netherlands)

Martinez Verdugo, J.M.; Haverkort, Boudewijn R.H.M.; German, R.; Heindl, A.

2006-01-01

Deterministic and Stochastic Petri Nets (DSPNs) are a widely used high-level formalism for modeling discrete-event systems where events may occur either without consuming time, after a deterministic time, or after an exponentially distributed time. The underlying process dened by DSPNs, under

Towards a Notion of Distributed Time for Petri Nets

DEFF Research Database (Denmark)

Nielsen, Mogens; Sassone, Vladimiro; Srba, Jiří

2001-01-01

We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks — possibly o...... per place — allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models.......We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks — possibly one...

Properties of Distributed Timed-Arc Petri Nets

DEFF Research Database (Denmark)

Nielsen, M.; Sassone, V.; Srba, J.

2001-01-01

In [12] we started a research on a distributed-timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. This formalism enables to model e.g. hardware architectures like GALS. We give a formal...... definition of process semantics for our model and investigate several properties of local versus global timing: expressiveness, reachability and coverability....

Stochastic petri nets for wireless networks

CERN Document Server

Lei, Lei; Zhong, Zhangdui

2015-01-01

This SpringerBrief presents research in the application of Stochastic Petri Nets (SPN) to the performance evaluation of wireless networks under bursty traffic. It covers typical Quality-of-Service performance metrics such as mean throughput, average delay and packet dropping probability. Along with an introduction of SPN basics, the authors introduce the key motivation and challenges of using SPN to analyze the resource sharing performance in wireless networks. The authors explain two powerful modeling techniques that treat the well-known state space explosion problem: model decomposition and

Modeling, Analysis and Simulation of Simple One Machine-Two Product System Using Petri Nets = Basit Bir Makine-İki Ürün Sisteminin Petri Ağları Kullanılarak Modellenmesi, Analizi ve Simulasyonu

Directory of Open Access Journals (Sweden)

Özgür ARMANERİ

2006-01-01

Full Text Available As in many engineering fields, the design of manufacturing systems can be carried out using models. Petri nets have been used extensively to model and analyze manufacturing systems. Petri Nets, as graphical and mathematical tools, provide a uniform environment for modeling, format analysis and design of discrete event systems. The modeling, simulation and analysis of simple one machine-two product systems using Petri nets will be presented in this paper. Behavioral and structural properties of the Petri net model will be considered in details. Then, the Petri net model of one machine-two product system will be simulated using a simulation program.

XML as a format of expression of Object-Oriented Petri Nets

Directory of Open Access Journals (Sweden)

Petr Jedlička

2004-01-01

Full Text Available A number of object-oriented (OO variants have so far been devised for Petri Nets (PN. However, none of these variants has ever been described using an open, independent format – such as XML. This article suggests several possibilities and advantages of such a description. The outlined XML language definition for the description of object-oriented Petri Nets (OOPN is based on XMI (description of UML object-oriented models, SOX (simple description of general OO systems and PNML (an XML-based language used for the description of structured and modular PN. For OOPN, the XML form of description represents a standard format for storing as well as for transfer between various OOPN-processing (analysis, simulation, ... tools.

Modelling human factor with Petri nets

International Nuclear Information System (INIS)

Bedreaga, Luminita; Constantinescu, Cristina; Guzun, Basarab

2007-01-01

The human contribution to risk and safety of nuclear power plant operation can be best understood, assessed and quantified using tools to evaluate human reliability. Human reliability analysis becomes an important part of every probabilistic safety assessment and it is used to demonstrate that nuclear power plants designed with different safety levels are prepared to cope with severe accidents. Human reliability analysis in context of probabilistic safety assessment consists in: identifying human-system interactions important to safety; quantifying probabilities appropriate with these interactions. Nowadays, the complex system functions can be modelled using special techniques centred either on states space adequate to system or on events appropriate to the system. Knowing that complex system model consists in evaluating the likelihood of success, in other words, in evaluating the possible value for that system being in some state, the inductive methods which are based on the system states can be applied also for human reliability modelling. Thus, switching to the system states taking into account the human interactions, the underlying basis of the Petri nets can be successfully applied and the likelihoods appropriate to these states can also derived. The paper presents the manner to assess the human reliability quantification using Petri nets approach. The example processed in the paper is from human reliability documentation without a detailed human factor analysis (qualitative). The obtained results by these two kinds of methods are in good agreement. (authors)

Online Conformance Checking for Petri Nets and Event Streams

DEFF Research Database (Denmark)

Burattin, Andrea

2017-01-01

Within process mining, we can identify conformance checking as the task of computing the extent to which executions of a process model are in line with the reference behavior. Most approaches currently available in the literature (for imperative models, such as Petri nets) perform just a-posterio...

APPLYING PETRI NETS EXTENSIONS TO MODELING COMMERCIAL BANK ACTIVITY

Directory of Open Access Journals (Sweden)

Igor ENICOV

2017-02-01

Full Text Available The relevance of the study is determined by the need to improve the methods of modeling andsimulating commercial bank activity, including for the purpose of calculating, controlling and managingthe risk of the bank, in the context of the transition to the application of Basel III standards. Thisimprovement becomes necessary due to a direct transition to new regulatory standards when the internalassessments of the main risks become the initial data for calculating the capital adequacy of a bank. Thepurpose of this article is to argue the opportunity to formulate a theory of the commercial bank model onthe extensions of Petri nets theory. The main methods of research were the method of scientific abstractionand method of logical analysis. The main result obtained in the study and presented in the article is theargumentation of the possibility to analyze the quantitative and qualitative characteristics of acommercial bank with the help of Petri net extensions.

A Petri Net Definition of a System Description Language

DEFF Research Database (Denmark)

Jensen, Kurt; Kyng, Morten; Madsen, Ole Lehrmann

1979-01-01

This paper introduces a language for the description of systems with concurrency, and presents a formal definition of its semantics. The language is based on Delta and the semantic model is an extension of Petri nets with a data part and with expressions attached to transitions and to places....

Petri nets and fault diagnosis in nuclear reactors

International Nuclear Information System (INIS)

Jalel, N.A.; Nicholson, H.

1990-11-01

The possibility of applying Petri nets (Pns) as a modelling tool to represent any fault or accident that might occur in the Loss Of Fluid Test (LOFT) reactor, small scale pressurised water reactor, is discussed and analysed. Pns are developed to assist the nuclear reactor operator in identifying any fault or alarm that might arise in the power station. (author)

Aspects regarding at 13C isotope separation column control using Petri nets system

International Nuclear Information System (INIS)

Boca, M L; Ciortea, M E

2015-01-01

This paper is intended to show that Petri nets can be also applicable in the chemical industry. It used linear programming, modeling underlying Petri nets, especially discrete event systems for isotopic separation, the purpose of considering and control events in real-time through graphical representations. In this paper it is simulate the control of 13 C Isotope Separation column using Petri nets. The major problem with 13 C comes from the difficulty of obtaining it and raising its natural fraction. Carbon isotopes can be obtained using many methods, one of them being the cryogenic distillation of carbon monoxide. Some few aspects regarding operating conditions and the construction of such cryogenic plants are known today, and even less information are available as far as the separation process modeling and control are concerned. In fact, the efficient control of the carbon monoxide distillation process represents a necessity for large-scale 13 C production. Referring to a classic distillation process, some models for carbon isotope separation have been proposed, some based on mass, component and energy balance equations, some on the nonlinear wave theory or the Cohen equations. For modeling the system it was used Petri nets because in this case it is deal with discrete event systems. In use of the non-timed and with auxiliary times Petri model, the transport stream was divided into sections and these sections will be analyzed successively. Because of the complexity of the system and the large amount of calculations required it was not possible to analyze the system as a unitary whole. A first attempt to model the system as a unitary whole led to the blocking of the model during simulation, because of the large processing times. (paper)

Threat driven modeling framework using petri nets for e-learning system.

Science.gov (United States)

Khamparia, Aditya; Pandey, Babita

2016-01-01

Vulnerabilities at various levels are main cause of security risks in e-learning system. This paper presents a modified threat driven modeling framework, to identify the threats after risk assessment which requires mitigation and how to mitigate those threats. To model those threat mitigations aspects oriented stochastic petri nets are used. This paper included security metrics based on vulnerabilities present in e-learning system. The Common Vulnerability Scoring System designed to provide a normalized method for rating vulnerabilities which will be used as basis in metric definitions and calculations. A case study has been also proposed which shows the need and feasibility of using aspect oriented stochastic petri net models for threat modeling which improves reliability, consistency and robustness of the e-learning system.

A Petri Net-Based Software Process Model for Developing Process-Oriented Information Systems

Science.gov (United States)

Li, Yu; Oberweis, Andreas

Aiming at increasing flexibility, efficiency, effectiveness, and transparency of information processing and resource deployment in organizations to ensure customer satisfaction and high quality of products and services, process-oriented information systems (POIS) represent a promising realization form of computerized business information systems. Due to the complexity of POIS, explicit and specialized software process models are required to guide POIS development. In this chapter we characterize POIS with an architecture framework and present a Petri net-based software process model tailored for POIS development with consideration of organizational roles. As integrated parts of the software process model, we also introduce XML nets, a variant of high-level Petri nets as basic methodology for business processes modeling, and an XML net-based software toolset providing comprehensive functionalities for POIS development.

A Petri Nets Model for Blockchain Analysis

OpenAIRE

Pinna, Andrea; Tonelli, Roberto; Orrú, Matteo; Marchesi, Michele

2017-01-01

A Blockchain is a global shared infrastructure where cryptocurrency transactions among addresses are recorded, validated and made publicly available in a peer- to-peer network. To date the best known and important cryptocurrency is the bitcoin. In this paper we focus on this cryptocurrency and in particular on the modeling of the Bitcoin Blockchain by using the Petri Nets formalism. The proposed model allows us to quickly collect information about identities owning Bitcoin addresses and to re...

The risk management of perishable supply chain based on coloured Petri Net modeling

Directory of Open Access Journals (Sweden)

Lu Liu

2018-03-01

Full Text Available The supply chain of perishable products is a combination of information organization, sharing and integration. The information modeling of supply chain is constructed to abstract key quality information including environment information, processing procedures and product quality assessments based on principle of quality safety factors and property of decay rate. The coloured Petri Net is applied for integrated description of independent information classification, aiming at risk identification and risk management framework. Well, according to the quality deterioration tendency, risk grades management and decision-making system are established. Practically, the circulation system of aquatic products is studied in this paper for full processing description. The simulation experiments are manipulated on environmental information, processing information and product quality information by the coloured Petri Net. Eventually, the conclusion turns out precisely as such that the coloured Petri Net conclusive for information classification and information transmission while integrated information management is available of efficient risk identification and decision-making system in supply chain of perishable products. Meanwhile, the validity of evaluating management and shelf-life estimation of perishable products are technically feasible.

Fluid Survival Tool: A Model Checker for Hybrid Petri Nets

NARCIS (Netherlands)

Postema, Björn Frits; Remke, Anne Katharina Ingrid; Haverkort, Boudewijn R.H.M.; Ghasemieh, Hamed

2014-01-01

Recently, algorithms for model checking Stochastic Time Logic (STL) on Hybrid Petri nets with a single general one-shot transition (HPNG) have been introduced. This paper presents a tool for model checking HPNG models against STL formulas. A graphical user interface (GUI) not only helps to

Control of Discrete-Event Systems Automata and Petri Net Perspectives

CERN Document Server

Silva, Manuel; Schuppen, Jan

2013-01-01

Control of Discrete-event Systems provides a survey of the most important topics in the discrete-event systems theory with particular focus on finite-state automata, Petri nets and max-plus algebra. Coverage ranges from introductory material on the basic notions and definitions of discrete-event systems to more recent results. Special attention is given to results on supervisory control, state estimation and fault diagnosis of both centralized and distributed/decentralized systems developed in the framework of the Distributed Supervisory Control of Large Plants (DISC) project. Later parts of the text are devoted to the study of congested systems though fluidization, an over approximation allowing a much more efficient study of observation and control problems of timed Petri nets. Finally, the max-plus algebraic approach to the analysis and control of choice-free systems is also considered. Control of Discrete-event Systems provides an introduction to discrete-event systems for readers that are not familiar wi...

Model checking of time Petri nets using the state class timed automaton

DEFF Research Database (Denmark)

Lime, Didier; Roux, Olivier H.

2006-01-01

In this paper, we propose a method for building the state class graph of a bounded time Petri net (TPN) as a timed automaton (TA), which we call the state class timed automaton. We consider bounded TPN, whose underlying net is not necessarily bounded. We prove that our translation preserves the b...

Transactions on Petri Nets and Other Models of Concurrency VI

DEFF Research Database (Denmark)

The sixth volume of ToPNoC includes revised versions of selected papers from workshops and tutorials held at the 32nd International Conference on Application and Theory of Petri Nets and Concurrency. It also contains a special section on Networks, Protocols, and Services, as well as a contributed...

Petri Net-Based R&D Process Modeling and Optimization for Composite Materials

Directory of Open Access Journals (Sweden)

Xiaomei Hu

2013-01-01

Full Text Available Considering the current R&D process for new composite materials involves some complex details, such as formula design, specimen/sample production, materials/sample test, assessment, materials/sample feedback from customers, and mass production, the workflow model of Petri net-based R&D process for new composite materials’ is proposed. By analyzing the time property of the whole Petri net, the optimized model for new composite materials R&D workflow is further proposed. By analyzing the experiment data and application in some materials R&D enterprise, it is demonstrated that the workflow optimization model shortens the period of R&D on new materials for 15%, definitely improving the R&D efficiency. This indicates the feasibility and availability of the model.

An Extended Petri-Net Based Approach for Supply Chain Process Enactment in Resource-Centric Web Service Environment

Science.gov (United States)

Wang, Xiaodong; Zhang, Xiaoyu; Cai, Hongming; Xu, Boyi

Enacting a supply-chain process involves variant partners and different IT systems. REST receives increasing attention for distributed systems with loosely coupled resources. Nevertheless, resource model incompatibilities and conflicts prevent effective process modeling and deployment in resource-centric Web service environment. In this paper, a Petri-net based framework for supply-chain process integration is proposed. A resource meta-model is constructed to represent the basic information of resources. Then based on resource meta-model, XML schemas and documents are derived, which represent resources and their states in Petri-net. Thereafter, XML-net, a high level Petri-net, is employed for modeling control and data flow of process. From process model in XML-net, RESTful services and choreography descriptions are deduced. Therefore, unified resource representation and RESTful services description are proposed for cross-system integration in a more effective way. A case study is given to illustrate the approach and the desirable features of the approach are discussed.

A knowledge-base verification of NPP expert systems using extended Petri nets

International Nuclear Information System (INIS)

Kwon, Il Won; Seong, Poong Hyun

1995-01-01

The verification phase of knowledge base is an important part for developing reliable expert systems, especially in nuclear industry. Although several strategies or tools have been developed to perform potential error checking, they often neglect the reliability of verification methods. Because a Petri net provides a uniform mathematical formalization of knowledge base, it has been employed for knowledge base verification. In this work, we devise and suggest an automated tool, called COKEP (Checker Of Knowledge base using Extended Petri net), for detecting incorrectness, inconsistency, and incompleteness in a knowledge base. The scope of the verification problem is expanded to chained errors, unlike previous studies that assumed error incidence to be limited to rule pairs only. In addition, we consider certainty factor in checking, because most of knowledge bases have certainty factors

Reliability Analysis of Core Protection Calculator System by Combining Petri Net and Fault Tree

International Nuclear Information System (INIS)

Kim, Hyejin; Kim, Jonghyun

2013-01-01

This paper proposes an approach to analyzing the reliability of digital systems by combining Petri net (PN) and Fault tree. The Petri net allows modeling event dependencies and interaction, to represent the time sequence, and to model assumptions for dynamic events. The Petri net model can be straightforwardly transformed to fault tree using the gate. Then, the FT can be integrated into the existing PSA. This paper applies the approach to the reliability analysis of Core Protection Calculator System (CPCS). Digital technology is replacing the analog instrumentation and control (I and C) systems in both new and upgraded nuclear power plants. As digital systems are introduced to nuclear power plants, issues related with reliability analyses of these digital systems are being raised. One of these issues is that static fault tree (FT) and event tree (ET) approach cannot properly account for dynamic interactions in the digital systems, such as multiple top events, logic loops and time delay. Many methods have been proposed to solve the problems, but there is no single method that is universally accepted for the application to the current generation probabilistic safety analysis (PSA)

Reliability Analysis of Core Protection Calculator System by Combining Petri Net and Fault Tree

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyejin; Kim, Jonghyun [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2013-10-15

This paper proposes an approach to analyzing the reliability of digital systems by combining Petri net (PN) and Fault tree. The Petri net allows modeling event dependencies and interaction, to represent the time sequence, and to model assumptions for dynamic events. The Petri net model can be straightforwardly transformed to fault tree using the gate. Then, the FT can be integrated into the existing PSA. This paper applies the approach to the reliability analysis of Core Protection Calculator System (CPCS). Digital technology is replacing the analog instrumentation and control (I and C) systems in both new and upgraded nuclear power plants. As digital systems are introduced to nuclear power plants, issues related with reliability analyses of these digital systems are being raised. One of these issues is that static fault tree (FT) and event tree (ET) approach cannot properly account for dynamic interactions in the digital systems, such as multiple top events, logic loops and time delay. Many methods have been proposed to solve the problems, but there is no single method that is universally accepted for the application to the current generation probabilistic safety analysis (PSA)

Robust modelling and simulation integration of SIMIO with coloured petri nets

CERN Document Server

De La Mota, Idalia Flores; Mujica Mota, Miguel; Angel Piera, Miquel

2017-01-01

This book presents for the first time a methodology that combines the power of a modelling formalism such as colored petri nets with the flexibility of a discrete event program such as SIMIO. Industrial practitioners have seen the growth of simulation as a methodology for tacking problems in which variability is the common denominator. Practically all industrial systems, from manufacturing to aviation are considered stochastic systems. Different modelling techniques have been developed as well as mathematical techniques for formalizing the cause-effect relationships in industrial and complex systems. The methodology in this book illustrates how complexity in modelling can be tackled by the use of coloured petri nets, while at the same time the variability present in systems is integrated in a robust fashion. The book can be used as a concise guide for developing robust models, which are able to efficiently simulate the cause-effect relationships present in complex industrial systems without losing the simulat...

Formal Verification of Computerized Procedure with Colored Petri Nets

International Nuclear Information System (INIS)

Kim, Yun Goo; Shin, Yeong Cheol

2008-01-01

Computerized Procedure System (CPS) supports nuclear power plant operators in performing operating procedures which are instructions to guide in monitoring, decision making and controlling nuclear power plants. Computerized Procedure (CP) should be loaded to CPS. Due to its execution characteristic, computerized procedure acts like a software in CPS. For example, procedure flows are determined by operator evaluation and computerized procedure logic which are pre-defined. So the verification of Computerized Procedure logic and execution flow is needed before computerized procedures are installed in the system. Formal verification methods are proposed and the modeling of operating procedures with Coloured Petri Nets(CP-nets) is presented

Formal Specification and Verification of Real-Time Multi-Agent Systems using Timed-Arc Petri Nets

Directory of Open Access Journals (Sweden)

QASIM, A.

2015-08-01

Full Text Available In this study we have formally specified and verified the actions of communicating real-time software agents (RTAgents. Software agents are expected to work autonomously and deal with unfamiliar situations astutely. Achieving cent percent test cases coverage for these agents has always been a problem due to limited resources. Also a high degree of dependability and predictability is expected from real-time software agents. In this research we have used Timed-Arc Petri Net's for formal specification and verification. Formal specification of e-agents has been done in the past using Linear Temporal Logic (LTL but we believe that Timed-Arc Petri Net's being more visually expressive provides a richer framework for such formalism. A case study of Stock Market System (SMS based on Real Time Multi Agent System framework (RTMAS using Timed-Arc Petri Net's is taken to illustrate the proposed modeling approach. The model was verified used AF, AG, EG, and EF fragments of Timed Computational Tree Logic (TCTL via translations to timed automata.

A modeling method of semiconductor fabrication flows with extended knowledge hybrid Petri nets

Institute of Scientific and Technical Information of China (English)

Zhou Binghai; Jiang Shuyu; Wang Shijin; Wu bin

2008-01-01

A modeling method of extended knowledge hybrid Petri nets (EKHPNs), incorporating object-oriented methods into hybrid Petri nets (HPNs), was presented and used for the representation and modeling of semiconductor wafer fabrication flows. To model the discrete and continuous parts of a complex semiconductor wafer fabrication flow, the HPNs were introduced into the EKHPNs. Object-oriented methods were combined into the EKHPNs for coping with the complexity of the fabrication flow. Knowledge annotations were introduced to solve input and output conflicts of the EKHPNs.Finally, to demonstrate the validity of the EKHPN method, a real semiconductor wafer fabrication case was used to illustrate the modeling procedure. The modeling results indicate that the proposed method can be used to model a complex semiconductor wafer fabrication flow expediently.

Model-Based Testing of a Reactive System with Coloured Petri Nets

DEFF Research Database (Denmark)

Tjell, Simon

2006-01-01

In this paper, a reactive and nondeterministic system is tested. This is doneby applying a generic model that has been specified as a configurable Coloured PetriNet. In this way, model-based testing is possible for a wide class of reactive system atthe level of discrete events. Concurrently...

Modeling of system reliability Petri nets with aging tokens

International Nuclear Information System (INIS)

Volovoi, V.

2004-01-01

The paper addresses the dynamic modeling of degrading and repairable complex systems. Emphasis is placed on the convenience of modeling for the end user, with special attention being paid to the modeling part of a problem, which is considered to be decoupled from the choice of solution algorithms. Depending on the nature of the problem, these solution algorithms can include discrete event simulation or numerical solution of the differential equations that govern underlying stochastic processes. Such modularity allows a focus on the needs of system reliability modeling and tailoring of the modeling formalism accordingly. To this end, several salient features are chosen from the multitude of existing extensions of Petri nets, and a new concept of aging tokens (tokens with memory) is introduced. The resulting framework provides for flexible and transparent graphical modeling with excellent representational power that is particularly suited for system reliability modeling with non-exponentially distributed firing times. The new framework is compared with existing Petri-net approaches and other system reliability modeling techniques such as reliability block diagrams and fault trees. The relative differences are emphasized and illustrated with several examples, including modeling of load sharing, imperfect repair of pooled items, multiphase missions, and damage-tolerant maintenance. Finally, a simple implementation of the framework using discrete event simulation is described

Condensed State Spaces for Symmetrical Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1996-01-01

equivalence classes of states and equivalence classes of state changes. It is then possible to construct a condensed state space where each node represents an equivalence class of states while each arc represents an equivalence class of state changes. Such a condensed state space is often much smaller than...... the full state space and it is also much faster to construct. Nevertheless, it is possible to use the condensed state space to verify the same kind of behavioural properties as the full state space. Hence, we do not lose analytic power. We define state spaces and condensed state spaces for a language......-nets (or Petri nets in general) - although such knowledge will, of course, be a help. The first four sections of the paper introduce the basic concepts of CP-nets. The next three sections deal with state spaces, condensed state spaces and computer tools for state space analysis. Finally, there is a short...

Modeling and performance analysis of a closed-loop supply chain using first-order hybrid Petri nets

Directory of Open Access Journals (Sweden)

Imane Outmal

2016-05-01

Full Text Available Green or closed-loop supply chain had been the focus of many manufacturers during the last decade. The application of closed-loop supply chain in today’s manufacturing is not only due to growing environmental concerns and the recognition of its benefits in reducing greenhouse gas emissions, energy consumption, and meeting a more strict environmental regulations but it also offers economic competitive advantages if appropriately managed. First-order hybrid Petri nets represent a powerful graphical and mathematical formalism to map and analyze the dynamics of complex systems such as closed-loop supply chain networks. This article aims at illustrating the use of first-order hybrid Petri nets to model a closed-loop supply chain network and evaluate its operational, financial, and environmental performance measures under different management policies. Actual data from auto manufacturer in the United States are used to validate network’s performance under both tactical and strategic decision-making, namely, (1 tactical decision—production policies: increase of recovered versus new components and (2 strategic decision—closed-loop supply chain network structure: manufacturer internal recovery process or recovery process done by a third-party collection and recovery center. The work presented in this article is an extension of the use of first-order hybrid Petri nets as a modeling and performance analysis tool from supply chain to closed-loop supply chain. The modularity property of first-order hybrid Petri nets has been used in the modeling process, and the simulation and analysis of the modeled network are done in MATLAB® environment. The results of the experiments depict that first-order hybrid Petri nets are a powerful modeling and analysis formalism for closed-loop supply chain networks and can be further used as an efficient decision-making tool at both tactical and strategic levels. Unlike other researches on modeling supply chain

Evaluation of Cyber Security and Modelling of Risk Propagation with Petri Nets

Directory of Open Access Journals (Sweden)

Marcin Szpyrka

2017-02-01

Full Text Available This article presents a new method of risk propagation among associated elements. On thebasis of coloured Petri nets, a new class called propagation nets is defined. This class providesa formal model of a risk propagation. The proposed method allows for model relations betweennodes forming the network structure. Additionally, it takes into account the bidirectional relationsbetween components as well as relations between isomorphic, symmetrical components in variousbranches of the network. This method is agnostic in terms of use in various systems and it canbe adapted to the propagation model of any systems’ characteristics; however, it is intentionallyproposed to assess the risk of critical infrastructures. In this paper, as a proof of concept example, weshow the formal model of risk propagation proposed within the project Cyberspace Security ThreatsEvaluation System of the Republic of Poland. In the article, the idea of the method is presented aswell as its use case for evaluation of risk for cyber threats. With the adaptation of Petri nets, it ispossible to evaluate the risk for the particular node and assess the impact of this risk for all relatednodes including hierarchic relations of components as well as isomorphism of elements.

Coupling of Petri Net Models of the Mycobacterial Infection Process and Innate Immune Response

Directory of Open Access Journals (Sweden)

Rafael V. Carvalho

2015-04-01

Full Text Available Computational and mathematical modeling is important in support of a better understanding of complex behavior in biology. For the investigation of biological systems, researchers have used computers to construct, verify, and validate models that describe the mechanisms behind biological processes in multi-scale representations. In this paper we combine Petri net models that represent the mycobacterial infection process and innate immune response at various levels of organization, from molecular interaction to granuloma dissemination. In addition to the conventional graphical representation of the Petri net, the outcome of the model is projected onto a 3D model representing the zebrafish embryo. In this manner we provide a visualization of the process in a simulation framework that portrays the infection in the living system.

Modularization of biochemical networks based on classification of Petri net t-invariants.

Science.gov (United States)

Grafahrend-Belau, Eva; Schreiber, Falk; Heiner, Monika; Sackmann, Andrea; Junker, Björn H; Grunwald, Stefanie; Speer, Astrid; Winder, Katja; Koch, Ina

2008-02-08

Structural analysis of biochemical networks is a growing field in bioinformatics and systems biology. The availability of an increasing amount of biological data from molecular biological networks promises a deeper understanding but confronts researchers with the problem of combinatorial explosion. The amount of qualitative network data is growing much faster than the amount of quantitative data, such as enzyme kinetics. In many cases it is even impossible to measure quantitative data because of limitations of experimental methods, or for ethical reasons. Thus, a huge amount of qualitative data, such as interaction data, is available, but it was not sufficiently used for modeling purposes, until now. New approaches have been developed, but the complexity of data often limits the application of many of the methods. Biochemical Petri nets make it possible to explore static and dynamic qualitative system properties. One Petri net approach is model validation based on the computation of the system's invariant properties, focusing on t-invariants. T-invariants correspond to subnetworks, which describe the basic system behavior.With increasing system complexity, the basic behavior can only be expressed by a huge number of t-invariants. According to our validation criteria for biochemical Petri nets, the necessary verification of the biological meaning, by interpreting each subnetwork (t-invariant) manually, is not possible anymore. Thus, an automated, biologically meaningful classification would be helpful in analyzing t-invariants, and supporting the understanding of the basic behavior of the considered biological system. Here, we introduce a new approach to automatically classify t-invariants to cope with network complexity. We apply clustering techniques such as UPGMA, Complete Linkage, Single Linkage, and Neighbor Joining in combination with different distance measures to get biologically meaningful clusters (t-clusters), which can be interpreted as modules. To find

Modularization of biochemical networks based on classification of Petri net t-invariants

Directory of Open Access Journals (Sweden)

Grunwald Stefanie

2008-02-01

Full Text Available Abstract Background Structural analysis of biochemical networks is a growing field in bioinformatics and systems biology. The availability of an increasing amount of biological data from molecular biological networks promises a deeper understanding but confronts researchers with the problem of combinatorial explosion. The amount of qualitative network data is growing much faster than the amount of quantitative data, such as enzyme kinetics. In many cases it is even impossible to measure quantitative data because of limitations of experimental methods, or for ethical reasons. Thus, a huge amount of qualitative data, such as interaction data, is available, but it was not sufficiently used for modeling purposes, until now. New approaches have been developed, but the complexity of data often limits the application of many of the methods. Biochemical Petri nets make it possible to explore static and dynamic qualitative system properties. One Petri net approach is model validation based on the computation of the system's invariant properties, focusing on t-invariants. T-invariants correspond to subnetworks, which describe the basic system behavior. With increasing system complexity, the basic behavior can only be expressed by a huge number of t-invariants. According to our validation criteria for biochemical Petri nets, the necessary verification of the biological meaning, by interpreting each subnetwork (t-invariant manually, is not possible anymore. Thus, an automated, biologically meaningful classification would be helpful in analyzing t-invariants, and supporting the understanding of the basic behavior of the considered biological system. Methods Here, we introduce a new approach to automatically classify t-invariants to cope with network complexity. We apply clustering techniques such as UPGMA, Complete Linkage, Single Linkage, and Neighbor Joining in combination with different distance measures to get biologically meaningful clusters (t

Polymorphism and Module-Reuse Mechanisms for Algebraic Petri Nets in CoopnTools

OpenAIRE

Buffo, Mathieu; Buchs, Didier; Donatelli, S.; Kleijn, J.

1999-01-01

This paper introduces CoopnTools, a tool set allowing the support of object-oriented specifications written by means of the language CO-OPN/2, based on synchronised algebraic Petri nets. In particular, this paper shows how concrete mechanisms dealing with polymorphism and module-reuse are implemented in CoopnTools.

A Timed Colored Petri Net Simulation-Based Self-Adaptive Collaboration Method for Production-Logistics Systems

Directory of Open Access Journals (Sweden)

Zhengang Guo

2017-03-01

Full Text Available Complex and customized manufacturing requires a high level of collaboration between production and logistics in a flexible production system. With the widespread use of Internet of Things technology in manufacturing, a great amount of real-time and multi-source manufacturing data and logistics data is created, that can be used to perform production-logistics collaboration. To solve the aforementioned problems, this paper proposes a timed colored Petri net simulation-based self-adaptive collaboration method for Internet of Things-enabled production-logistics systems. The method combines the schedule of token sequences in the timed colored Petri net with real-time status of key production and logistics equipment. The key equipment is made ‘smart’ to actively publish or request logistics tasks. An integrated framework based on a cloud service platform is introduced to provide the basis for self-adaptive collaboration of production-logistics systems. A simulation experiment is conducted by using colored Petri nets (CPN Tools to validate the performance and applicability of the proposed method. Computational experiments demonstrate that the proposed method outperforms the event-driven method in terms of reductions of waiting time, makespan, and electricity consumption. This proposed method is also applicable to other manufacturing systems to implement production-logistics collaboration.

Coloured Petri Nets: Basic Concepts, Analysis Methods and Practical Use. Vol. 1, Basic Concepts

DEFF Research Database (Denmark)

Jensen, Kurt

This three-volume work presents a coherent description of the theoretical and practical aspects of coloured Petri nets. These CP-nets are shown to be a full-fledged language for the design, specification, simulation, validation and implementation of large software systems. The introductory first...... volume contains the formal definition of CP-nets and the mathematical theory behind their analysis methods. It gives a detailed presentation of many small examples and a brief overview of some industrial applications. The purpose of the book is to teach the reader how to construct CP-net models...

Software hazard analysis for nuclear digital protection system by Colored Petri Net

International Nuclear Information System (INIS)

Bai, Tao; Chen, Wei-Hua; Liu, Zhen; Gao, Feng

2017-01-01

Highlights: •A dynamic hazard analysis method is proposed for the safety-critical software. •The mechanism relies on Colored Petri Net. •Complex interactions between software and hardware are captured properly. •Common failure mode in software are identified effectively. -- Abstract: The software safety of a nuclear digital protection system is critical for the safety of nuclear power plants as any software defect may result in severe damage. In order to ensure the safety and reliability of safety-critical digital system products and their applications, software hazard analysis is required to be performed during the lifecycle of software development. The dynamic software hazard modeling and analysis method based on Colored Petri Net is proposed and applied to the safety-critical control software of the nuclear digital protection system in this paper. The analysis results show that the proposed method can explain the complex interactions between software and hardware and identify the potential common cause failure in software properly and effectively. Moreover, the method can find the dominant software induced hazard to safety control actions, which aids in increasing software quality.

A Case Study on Coloured Petri Nets in Object-oriented Analysis and Design

DEFF Research Database (Denmark)

Barros, Joao Paulo; Jørgensen, Jens Bæk

2005-01-01

In this paper, we first demonstrate how a coloured Petri nets (CPN) model can be used to capture requirements for a considered example system, an elevator controller. Then, we show how this requirements-level CPN model is transformed into a design-level object-oriented CPN model, which...

Protos2CPN: using colored Petri nets for confuguring and testing business processes

NARCIS (Netherlands)

Gottschalk, F.; Aalst, van der W.M.P.; Vullers - Jansen, M.H.; Verbeek, H.M.W.

2008-01-01

Protos is a popular tool for business process modelling used in more than 1,500 organizations. It has a built-in Petri-net-based simulation engine which shows key performance indicators for the modelled processes. Reference process models offered for Protos reduce modelling efforts by providing

Dynamical Scheduling and Robust Control in Uncertain Environments with Petri Nets for DESs

Directory of Open Access Journals (Sweden)

Dimitri Lefebvre

2017-10-01

Full Text Available This paper is about the incremental computation of control sequences for discrete event systems in uncertain environments where uncontrollable events may occur. Timed Petri nets are used for this purpose. The aim is to drive the marking of the net from an initial value to a reference one, in minimal or near-minimal time, by avoiding forbidden markings, deadlocks, and dead branches. The approach is similar to model predictive control with a finite set of control actions. At each step only a small area of the reachability graph is explored: this leads to a reasonable computational complexity. The robustness of the resulting trajectory is also evaluated according to a risk probability. A sufficient condition is provided to compute robust trajectories. The proposed results are applicable to a large class of discrete event systems, in particular in the domains of flexible manufacturing. However, they are also applicable to other domains as communication, computer science, transportation, and traffic as long as the considered systems admit Petri Nets (PNs models. They are suitable for dynamical deadlock-free scheduling and reconfiguration problems in uncertain environments.

Distributed embedded controller development with petri nets application to globally-asynchronous locally-synchronous systems

CERN Document Server

Moutinho, Filipe de Carvalho

2016-01-01

This book describes a model-based development approach for globally-asynchronous locally-synchronous distributed embedded controllers.  This approach uses Petri nets as modeling formalism to create platform and network independent models supporting the use of design automation tools.  To support this development approach, the Petri nets class in use is extended with time-domains and asynchronous-channels. The authors’ approach uses models not only providing a better understanding of the distributed controller and improving the communication among the stakeholders, but also to be ready to support the entire lifecycle, including the simulation, the verification (using model-checking tools), the implementation (relying on automatic code generators), and the deployment of the distributed controller into specific platforms. Uses a graphical and intuitive modeling formalism supported by design automation tools; Enables verification, ensuring that the distributed controller was correctly specified; Provides flex...

Research on user behavior authentication model based on stochastic Petri nets

Science.gov (United States)

Zhang, Chengyuan; Xu, Haishui

2017-08-01

A behavioural authentication model based on stochastic Petri net is proposed to meet the randomness, uncertainty and concurrency characteristics of user behaviour. The use of random models in the location, changes, arc and logo to describe the characteristics of a variety of authentication and game relationships, so as to effectively implement the graphical user behaviour authentication model analysis method, according to the corresponding proof to verify the model is valuable.

Pascal Semantics by a Combination of Denotational Semantics and High-level Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt; Schmidt, Erik Meineche

1986-01-01

This paper describes the formal semantics of a subset of PASCAL, by means of a semantic model based on a combination of denotational semantics and high-level Petri nets. It is our intention that the paper can be used as part of the written material for an introductory course in computer science....

FORMATION OF THE SYNTHESIS ALGORITHMS OF THE COORDINATING CONTROL SYSTEMS BY MEANS OF THE AUTOMATIC GENERATION OF PETRI NETS

Directory of Open Access Journals (Sweden)

A. A. Gurskiy

2016-09-01

Full Text Available The coordinating control system by drives of the robot-manipulator is presented in this article. The purpose of the scientific work is the development and research of the new algorithms for parametric synthesis of the coordinating control systems. To achieve this aim it is necessary to develop the system generating the required parametric synthesis algorithms and performing the necessary procedures according to the generated algorithm. This scientific work deals with the synthesis of Petri net in the specific case with the automatic generation of Petri nets.

Specification and Verification of Medical Monitoring System Using Petri-nets.

Science.gov (United States)

Majma, Negar; Babamir, Seyed Morteza

2014-07-01

To monitor the patient behavior, data are collected from patient's body by a medical monitoring device so as to calculate the output using embedded software. Incorrect calculations may endanger the patient's life if the software fails to meet the patient's requirements. Accordingly, the veracity of the software behavior is a matter of concern in the medicine; moreover, the data collected from the patient's body are fuzzy. Some methods have already dealt with monitoring the medical monitoring devices; however, model based monitoring fuzzy computations of such devices have been addressed less. The present paper aims to present synthesizing a fuzzy Petri-net (FPN) model to verify behavior of a sample medical monitoring device called continuous infusion insulin (INS) because Petri-net (PN) is one of the formal and visual methods to verify the software's behavior. The device is worn by the diabetic patients and then the software calculates the INS dose and makes a decision for injection. The input and output of the infusion INS software are not crisp in the real world; therefore, we present them in fuzzy variables. Afterwards, we use FPN instead of clear PN to model the fuzzy variables. The paper follows three steps to synthesize an FPN to deal with verification of the infusion INS device: (1) Definition of fuzzy variables, (2) definition of fuzzy rules and (3) design of the FPN model to verify the software behavior.

Verification of Liveness Properties on Closed Timed-Arc Petri Nets

DEFF Research Database (Denmark)

Andersen, Mathias; Larsen, Heine G.; Srba, Jiri

2012-01-01

Verification of closed timed models by explicit state-space exploration methods is an alternative to the wide-spread symbolic techniques based on difference bound matrices (DBMs). A few experiments found in the literature confirm that for the reachability analysis of timed automata explicit...... techniques can compete with DBM-based algorithms, at least for situations where the constants used in the models are relatively small. To the best of our knowledge, the explicit methods have not yet been employed in the verification of liveness properties in Petri net models extended with time. We present...

A vector matching method for analysing logic Petri nets

Science.gov (United States)

Du, YuYue; Qi, Liang; Zhou, MengChu

2011-11-01

Batch processing function and passing value indeterminacy in cooperative systems can be described and analysed by logic Petri nets (LPNs). To directly analyse the properties of LPNs, the concept of transition enabling vector sets is presented and a vector matching method used to judge the enabling transitions is proposed in this article. The incidence matrix of LPNs is defined; an equation about marking change due to a transition's firing is given; and a reachable tree is constructed. The state space explosion is mitigated to a certain extent from directly analysing LPNs. Finally, the validity and reliability of the proposed method are illustrated by an example in electronic commerce.

Design and verification of distributed logic controllers with application of Petri nets

Energy Technology Data Exchange (ETDEWEB)

Wiśniewski, Remigiusz; Grobelna, Iwona; Grobelny, Michał; Wiśniewska, Monika [University of Zielona Góra, Licealna 9, 65-417 Zielona Góra (Poland)

2015-12-31

The paper deals with the designing and verification of distributed logic controllers. The control system is initially modelled with Petri nets and formally verified against structural and behavioral properties with the application of the temporal logic and model checking technique. After that it is decomposed into separate sequential automata that are working concurrently. Each of them is re-verified and if the validation is successful, the system can be finally implemented.

Petri net-based prediction of therapeutic targets that recover abnormally phosphorylated proteins in muscle atrophy.

Science.gov (United States)

Jung, Jinmyung; Kwon, Mijin; Bae, Sunghwa; Yim, Soorin; Lee, Doheon

2018-03-05

Muscle atrophy, an involuntary loss of muscle mass, is involved in various diseases and sometimes leads to mortality. However, therapeutics for muscle atrophy thus far have had limited effects. Here, we present a new approach for therapeutic target prediction using Petri net simulation of the status of phosphorylation, with a reasonable assumption that the recovery of abnormally phosphorylated proteins can be a treatment for muscle atrophy. The Petri net model was employed to simulate phosphorylation status in three states, i.e. reference, atrophic and each gene-inhibited state based on the myocyte-specific phosphorylation network. Here, we newly devised a phosphorylation specific Petri net that involves two types of transitions (phosphorylation or de-phosphorylation) and two types of places (activation with or without phosphorylation). Before predicting therapeutic targets, the simulation results in reference and atrophic states were validated by Western blotting experiments detecting five marker proteins, i.e. RELA, SMAD2, SMAD3, FOXO1 and FOXO3. Finally, we determined 37 potential therapeutic targets whose inhibition recovers the phosphorylation status from an atrophic state as indicated by the five validated marker proteins. In the evaluation, we confirmed that the 37 potential targets were enriched for muscle atrophy-related terms such as actin and muscle contraction processes, and they were also significantly overlapping with the genes associated with muscle atrophy reported in the Comparative Toxicogenomics Database (p-value net. We generated a list of the potential therapeutic targets whose inhibition recovers abnormally phosphorylated proteins in an atrophic state. They were evaluated by various approaches, such as Western blotting, GO terms, literature, known muscle atrophy-related genes and shortest path analysis. We expect the new proposed strategy to provide an understanding of phosphorylation status in muscle atrophy and to provide assistance towards

Coloured Petri Nets: Basic Concepts, Analysis Methods and Practical Use. Vol. 2, Analysis Methods

DEFF Research Database (Denmark)

Jensen, Kurt

ideas behind the analysis methods are described as well as the mathematics on which they are based and also how the methods are supported by computer tools. Some parts of the volume are theoretical while others are application oriented. The purpose of the volume is to teach the reader how to use......This three-volume work presents a coherent description of the theoretical and practical aspects of coloured Petri nets (CP-nets). The second volume contains a detailed presentation of the analysis methods for CP-nets. They allow the modeller to investigate dynamic properties of CP-nets. The main...... the formal analysis methods, which does not require a deep understanding of the underlying mathematical theory....

'PSA-SPN' - A Parameter Sensitivity Analysis Method Using Stochastic Petri Nets: Application to a Production Line System

International Nuclear Information System (INIS)

Labadi, Karim; Saggadi, Samira; Amodeo, Lionel

2009-01-01

The dynamic behavior of a discrete event dynamic system can be significantly affected for some uncertain changes in its decision parameters. So, parameter sensitivity analysis would be a useful way in studying the effects of these changes on the system performance. In the past, the sensitivity analysis approaches are frequently based on simulation models. In recent years, formal methods based on stochastic process including Markov process are proposed in the literature. In this paper, we are interested in the parameter sensitivity analysis of discrete event dynamic systems by using stochastic Petri nets models as a tool for modelling and performance evaluation. A sensitivity analysis approach based on stochastic Petri nets, called PSA-SPN method, will be proposed with an application to a production line system.

Modelling the protocol stack in NCS with deterministic and stochastic petri net

Science.gov (United States)

Hui, Chen; Chunjie, Zhou; Weifeng, Zhu

2011-06-01

Protocol stack is the basis of the networked control systems (NCS). Full or partial reconfiguration of protocol stack offers both optimised communication service and system performance. Nowadays, field testing is unrealistic to determine the performance of reconfigurable protocol stack; and the Petri net formal description technique offers the best combination of intuitive representation, tool support and analytical capabilities. Traditionally, separation between the different layers of the OSI model has been a common practice. Nevertheless, such a layered modelling analysis framework of protocol stack leads to the lack of global optimisation for protocol reconfiguration. In this article, we proposed a general modelling analysis framework for NCS based on the cross-layer concept, which is to establish an efficiency system scheduling model through abstracting the time constraint, the task interrelation, the processor and the bus sub-models from upper and lower layers (application, data link and physical layer). Cross-layer design can help to overcome the inadequacy of global optimisation based on information sharing between protocol layers. To illustrate the framework, we take controller area network (CAN) as a case study. The simulation results of deterministic and stochastic Petri-net (DSPN) model can help us adjust the message scheduling scheme and obtain better system performance.

Performance Estimation for Hardware/Software codesign using Hierarchical Colored Petri Nets

DEFF Research Database (Denmark)

Grode, Jesper Nicolai Riis; Madsen, Jan; Jerraya, Ahmed-Amine

1998-01-01

This paper presents an approach for abstract modeling of the functional behavior of hardware architectures using Hierarchical Colored Petri Nets (HCPNs). Using HCPNs as architectural models has several advantages such as higher estimation accuracy, higher flexibility, and the need for only one...... estimation tool. This makes the approach very useful for designing component models used for performance estimation in Hardware/Software Codesign frameworks such as the LYCOS system. The paper presents the methodology and rules for designing component models using HCPNs. Two examples of architectural models...

Model-Based Requirements Analysis for Reactive Systems with UML Sequence Diagrams and Coloured Petri Nets

DEFF Research Database (Denmark)

Tjell, Simon; Lassen, Kristian Bisgaard

2008-01-01

In this paper, we describe a formal foundation for a specialized approach to automatically checking traces against real-time requirements. The traces are obtained from simulation of Coloured Petri Net (CPN) models of reactive systems. The real-time requirements are expressed in terms of a derivat...

State Token Petri Net modeling method for formal verification of computerized procedure including operator's interruptions of procedure execution flow

International Nuclear Information System (INIS)

Kim, Yun Goo; Seong, Poong Hyun

2012-01-01

The Computerized Procedure System (CPS) is one of the primary operating support systems in the digital Main Control Room. The CPS displays procedure on the computer screen in the form of a flow chart, and displays plant operating information along with procedure instructions. It also supports operator decision making by providing a system decision. A procedure flow should be correct and reliable, as an error would lead to operator misjudgement and inadequate control. In this paper we present a modeling for the CPS that enables formal verification based on Petri nets. The proposed State Token Petri Nets (STPN) also support modeling of a procedure flow that has various interruptions by the operator, according to the plant condition. STPN modeling is compared with Coloured Petri net when they are applied to Emergency Operating Computerized Procedure. A converting program for Computerized Procedure (CP) to STPN has been also developed. The formal verification and validation methods of CP with STPN increase the safety of a nuclear power plant and provide digital quality assurance means that are needed when the role and function of the CPS is increasing.

Petri net modeling of encrypted information flow in federated cloud

Science.gov (United States)

Khushk, Abdul Rauf; Li, Xiaozhong

2017-08-01

Solutions proposed and developed for the cost-effective cloud systems suffer from a combination of secure private clouds and less secure public clouds. Need to locate applications within different clouds poses a security risk to the information flow of the entire system. This study addresses this by assigning security levels of a given lattice to the entities of a federated cloud system. A dynamic flow sensitive security model featuring Bell-LaPadula procedures is explored that tracks and authenticates the secure information flow in federated clouds. Additionally, a Petri net model is considered as a case study to represent the proposed system and further validate the performance of the said system.

Manufacturing Scheduling Using Colored Petri Nets and Reinforcement Learning

Directory of Open Access Journals (Sweden)

Maria Drakaki

2017-02-01

Full Text Available Agent-based intelligent manufacturing control systems are capable to efficiently respond and adapt to environmental changes. Manufacturing system adaptation and evolution can be addressed with learning mechanisms that increase the intelligence of agents. In this paper a manufacturing scheduling method is presented based on Timed Colored Petri Nets (CTPNs and reinforcement learning (RL. CTPNs model the manufacturing system and implement the scheduling. In the search for an optimal solution a scheduling agent uses RL and in particular the Q-learning algorithm. A warehouse order-picking scheduling is presented as a case study to illustrate the method. The proposed scheduling method is compared to existing methods. Simulation and state space results are used to evaluate performance and identify system properties.

Automatic Structure-Based Code Generation from Coloured Petri Nets

DEFF Research Database (Denmark)

Kristensen, Lars Michael; Westergaard, Michael

2010-01-01

Automatic code generation based on Coloured Petri Net (CPN) models is challenging because CPNs allow for the construction of abstract models that intermix control flow and data processing, making translation into conventional programming constructs difficult. We introduce Process-Partitioned CPNs...... (PP-CPNs) which is a subclass of CPNs equipped with an explicit separation of process control flow, message passing, and access to shared and local data. We show how PP-CPNs caters for a four phase structure-based automatic code generation process directed by the control flow of processes....... The viability of our approach is demonstrated by applying it to automatically generate an Erlang implementation of the Dynamic MANET On-demand (DYMO) routing protocol specified by the Internet Engineering Task Force (IETF)....

Input-Output Relation and Time-Optimal Control of a Class of Hybrid Petri Nets Using (min,+) Semiring

Czech Academy of Sciences Publication Activity Database

Komenda, Jan; Zerhouni, N.; El Moudni, A.

2001-01-01

Roč. 11, 1/2 (2001), s. 59-76 ISSN 0924-6703 R&D Projects: GA AV ČR IAC1019007 Keywords : hybrid Petri nets%dioid algebra%modelling Subject RIV: BA - General Mathematics Impact factor: 0.552, year: 2001

A method of knowledge base verification for nuclear power plant expert systems using extended Petri Nets

International Nuclear Information System (INIS)

Kwon, I. W.; Seong, P. H.

1996-01-01

The adoption of expert systems mainly as operator supporting systems is becoming increasingly popular as the control algorithms of system become more and more sophisticated and complicated. The verification phase of knowledge base is an important part for developing reliable expert systems, especially in nuclear industry. Although several strategies or tools have been developed to perform potential error checking, they often neglect the reliability of verification methods. Because a Petri net provides a uniform mathematical formalization of knowledge base, it has been employed for knowledge base verification. In this work, we devise and suggest an automated tool, called COKEP(Checker of Knowledge base using Extended Petri net), for detecting incorrectness, inconsistency, and incompleteness in a knowledge base. The scope of the verification problem is expended to chained errors, unlike previous studies that assume error incidence to be limited to rule pairs only. In addition, we consider certainty factor in checking, because most of knowledge bases have certainly factors. 8 refs,. 2 figs,. 4 tabs. (author)

Distinguishing Environment and System in Coloured Petri Net Models of Reactive Systems

DEFF Research Database (Denmark)

Tjell, Simon

2007-01-01

This paper introduces and formally defines the environment-and-system-partitioned property for behavioral models of reactive systems expressed in the formal modeling language Coloured Petri Net. The purpose of the formalization is to make it possible to automatically validate any CPN model...... with respect to this property based on structural analysis. A model has the environment-and-system-partitioned property if it is based on a clear division between environment and system. This division is important in many model-driven approaches to software development such as model-based testing and automated...

Hierarchical Colored Petri Nets for Modeling and Analysis of Transit Signal Priority Control Systems

Directory of Open Access Journals (Sweden)

Yisheng An

2018-01-01

Full Text Available In this paper, we consider the problem of developing a model for traffic signal control with transit priority using Hierarchical Colored Petri nets (HCPN. Petri nets (PN are useful for state analysis of discrete event systems due to their powerful modeling capability and mathematical formalism. This paper focuses on their use to formalize the transit signal priority (TSP control model. In a four-phase traffic signal control model, the transit detection and two kinds of transit priority strategies are integrated to obtain the HCPN-based TSP control models. One of the advantages to use these models is the clear presentation of traffic light behaviors in terms of conditions and events that cause the detection of a priority request by a transit vehicle. Another advantage of the resulting models is that the correctness and reliability of the proposed strategies are easily analyzed. After their full reachable states are generated, the boundness, liveness, and fairness of the proposed models are verified. Experimental results show that the proposed control model provides transit vehicles with better effectiveness at intersections. This work helps advance the state of the art in the design of signal control models related to the intersection of roadways.

Stochastic Petri nets for the reliability analysis of communication network applications with alternate-routing

International Nuclear Information System (INIS)

Balakrishnan, Meera; Trivedi, Kishor S.

1996-01-01

In this paper, we present a comparative reliability analysis of an application on a corporate B-ISDN network under various alternate-routing protocols. For simple cases, the reliability problem can be cast into fault-tree models and solved rapidly by means of known methods. For more complex scenarios, state space (Markov) models are required. However, generation of large state space models can get very labor intensive and error prone. We advocate the use of stochastic reward nets (a variant of stochastic Petri nets) for the concise specification, automated generation and solution of alternate-routing protocols in networks. This paper is written in a tutorial style so as to make it accessible to a large audience

Flexible and Safe Control of Mobile Surface Systems, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The primary innovation of this work is a novel Petri net based approach for safe and flexible control of highly capable mobile surface systems, such as long-duration...

Formal Requirements Modeling for Reactive Systems with Coloured Petri Nets

DEFF Research Database (Denmark)

Tjell, Simon

This dissertation presents the contributions of seven publications all concerned with the application of Coloured Petri Nets (CPN) to requirements modeling for reactive systems. The publications are introduced along with relevant background material and related work, and their contributions...... to take into concern that the behavior of human actors is less likely to be predictable than the behavior of e.g. mechanical components.   In the second approach, the CPN model is parameterized and utilizes a generic and reusable CPN module operating as an SD interpreter. In addition to distinguishing...... and events. A tool is presented that allows automated validation of the structure of CPN models with respect to the guidelines. Next, three publications on integrating Jackson's Problem Frames with CPN requirements models are presented: The first publication introduces a method for systematically structuring...

A High-Level Petri Net Framework for Genetic Regulatory Networks

Directory of Open Access Journals (Sweden)

Banks Richard

2007-12-01

Full Text Available To understand the function of genetic regulatory networks in the development of cellular systems, we must not only realise the individual network entities, but also the manner by which they interact. Multi-valued networks are a promising qualitative approach for modelling such genetic regulatory networks, however, at present they have limited formal analysis techniques and tools. We present a flexible formal framework for modelling and analysing multi-valued genetic regulatory networks using high-level Petri nets and logic minimization techniques. We demonstrate our approach with a detailed case study in which part of the genetic regulatory network responsible for the carbon starvation stress response in Escherichia coli is modelled and analysed. We then compare and contrast this multivalued model to a corresponding Boolean model and consider their formal relationship.

Modelling M/G/1 queueing systems with server vacations using stochastic Petri nets

Directory of Open Access Journals (Sweden)

K Ramanath

2006-12-01

Full Text Available The theory of non-Markovian stochastic Petri nets is employed in this paper to derive an alternative method for studying the steady state behaviour of the M/G/1 vacation queueing system with a limited service discipline. Three types of vacation schemes are considered, and sytems with both a finite population and those with an infinite population (but finite capacity are considered. Simple numerical examples are also provided to illustrate the functionality of the methods and some useful performance measures for the system are obtained.

A Case Study on Coloured Petri Nets in Object-oriented Analysis and Design

DEFF Research Database (Denmark)

Barros, Joao Paulo; Jørgensen, Jens Bæk

2005-01-01

is structurally and conceptually closer to class diagrams and object-oriented programming languages. The CPN models reduce the gap between user-level requirements and the respective implementation, thus simplifying the implementation or code generation. Finally, we discuss the code generation from object-oriented......In this paper, we first demonstrate how a coloured Petri nets (CPN) model can be used to capture requirements for a considered example system, an elevator controller. Then, we show how this requirements-level CPN model is transformed into a design-level object-oriented CPN model, which...

Formal Specification and Verification of Real-Time Multi-Agent Systems using Timed-Arc Petri Nets

OpenAIRE

QASIM, A.; KAZMI, S. A. R.; FAKHIR, I.

2015-01-01

In this study we have formally specified and verified the actions of communicating real-time software agents (RTAgents). Software agents are expected to work autonomously and deal with unfamiliar situations astutely. Achieving cent percent test cases coverage for these agents has always been a problem due to limited resources. Also a high degree of dependability and predictability is expected from real-time software agents. In this research we have used Timed-Arc Petri Net...

A Timed Colored Petri Net Simulation-Based Self-Adaptive Collaboration Method for Production-Logistics Systems

OpenAIRE

Zhengang Guo; Yingfeng Zhang; Xibin Zhao; Xiaoyu Song

2017-01-01

Complex and customized manufacturing requires a high level of collaboration between production and logistics in a flexible production system. With the widespread use of Internet of Things technology in manufacturing, a great amount of real-time and multi-source manufacturing data and logistics data is created, that can be used to perform production-logistics collaboration. To solve the aforementioned problems, this paper proposes a timed colored Petri net simulation-based self-adaptive colla...

Stochastic Petri net analysis of a replicated file system

Science.gov (United States)

Bechta Dugan, Joanne; Ciardo, Gianfranco

1989-01-01

A stochastic Petri-net model of a replicated file system is presented for a distributed environment where replicated files reside on different hosts and a voting algorithm is used to maintain consistency. Witnesses, which simply record the status of the file but contain no data, can be used in addition to or in place of files to reduce overhead. A model sufficiently detailed to include file status (current or out-of-date), as well as failure and repair of hosts where copies or witnesses reside, is presented. The number of copies and witnesses is a parameter of the model. Two different majority protocols are examined, one where a majority of all copies and witnesses is necessary to form a quorum, and the other where only a majority of the copies and witnesses on operational hosts is needed. The latter, known as adaptive voting, is shown to increase file availability in most cases.

Detection and Modeling of Cyber Attacks with Petri Nets

Directory of Open Access Journals (Sweden)

Bartosz Jasiul

2014-12-01

Full Text Available The aim of this article is to present an approach to develop and verify a method of formal modeling of cyber threats directed at computer systems. Moreover, the goal is to prove that the method enables one to create models resembling the behavior of malware that support the detection process of selected cyber attacks and facilitate the application of countermeasures. The most common cyber threats targeting end users and terminals are caused by malicious software, called malware. The malware detection process can be performed either by matching their digital signatures or analyzing their behavioral models. As the obfuscation techniques make the malware almost undetectable, the classic signature-based anti-virus tools must be supported with behavioral analysis. The proposed approach to modeling of malware behavior is based on colored Petri nets. This article is addressed to cyber defense researchers, security architects and developers solving up-to-date problems regarding the detection and prevention of advanced persistent threats.

Evaluation of software architecture using fuzzy colored Petri nets

Directory of Open Access Journals (Sweden)

Vahid Abroshan

2013-02-01

Full Text Available Software Architecture (SA is one of the most important artifacts for life cycle of a software system because it incorporates some important decisions and principles for the system development. On the other hand, developing the systems based on uncertain and ambiguous requirement has been increased, significantly. Therefore, there have been significant attentions on SA requirements. In this paper, we present a new method for evaluation of performance characteristics based on a use case, response time, and queue length of SA. Since there are some ambiguities associated with considered systems, we use the idea of Fuzzy UML (F-UML diagrams. In addition, these diagrams have been enriched with performance annotations using proposed Fuzzy-SPT sub profile, the extended version of SPT profile proposed by OMG. Then, these diagrams are mapped into an executable model based on Fuzzy Colored Petri Nets (FCPN and finally the performance metrics are calculated using the proposed algorithms. We have implemented CPN-Tools for creating and evaluating the FCPN model.

System of failures diagnosis for energy transmission systems, using Petri nets

International Nuclear Information System (INIS)

Zapata, German; Grisales, John Faber; Gomez, Juan Camilo; Quintero Henao, Luis Fernando

2005-01-01

An expert system of second generation was used integrating the inverse Petri nets (RPN) and the systems based on rules (rule-based system) for the accomplishment of a program in Visual Basic that helps in the obtaining of an opportune and fast analysis of transmission of energy at the time of happening a fault in anymore of its components (line or bus). The program is proven in a portion of system IEEE -118 standard bus test system, in which two extracted cases of literature are developed and are the obtained results. Finally tests realized with the method developed in the laboratory of machines of the national university of Colombia, Medellin campus, simulating a system of transmission with two lines and two buses

Modeling and Application of Vehicular Cyber Physical System Based Petri Nets

Directory of Open Access Journals (Sweden)

Lin Chen

2014-11-01

Full Text Available Mobile cyber physical system (MCPS has been a hot research area, where mobile nodes can mobile, and communicate with each other. As a typical MCPS, vehicular cyber physical system (VCPS plays an important role in intelligent transportation, especially in collision avoidance. There is no, however, a formal modeling and analysis method for VCPS. In the paper, the modeling method based Petri nets (PN is presented. Furthermore, the behavior expression analysis method is also presented which can deal with arbitrary distribution timed transitions. Finally, a case is introduced to verify the effectiveness about proposed method, and the results show that VCPS can greatly reduce the reaction time of vehicles behind when emergent accident occurs and then enhance the traffic safety.

O potencial das redes de Petri em modelagem e análise de processos de negócio The potencial of Petri nets in modeling and analysis of workflow

Directory of Open Access Journals (Sweden)

Sílvia Inês Dallavalle de Pádua

2004-04-01

Full Text Available A tecnologia de gerenciamento workflow procura oferecer uma solução flexível em apoio aos processos de negócios, por meio da facilitação de modificações e da criação de novos processos. Entretanto, a falta de definição bem formalizada no que se refere à sintaxe e à semântica de tais técnicas dificulta análises mais complexas dos modelos. Nesse caso, redes de Petri atuam com excelente potencial, uma vez que possuem representação gráfica, são de fácil aprendizado, funcionam como linguagem de comunicação entre especialistas de diversas áreas, possibilitam descrever aspectos estáticos e dinâmicos do sistema a ser representado e ainda possuem o formalismo matemático necessário para métodos de análise já consagrados. O presente trabalho tem por objetivo, primeiramente, oferecer uma visão atualizada do estado da arte na área de modelagem de workflow baseada em redes de Petri e expor um exemplo de modelo de workflow com parâmetros de tempo e custo associados às transições da rede. O objetivo secundário é apresentar conceitos importantes de redes de Petri, workflow e rotas de processos.Unfortunately these systems and techniques do not have well-defined syntax and semantic, which makes harder the complex analysis of models. In this case, Petri nets have excellent potential to solve the problem, once they present graphic representation and easy understanding. They are used as a communication language among expert people in different areas, and may allow the description of static and dynamic aspects of the systems that have to be represented. Also, they have mathematic formalism, which make possibly the use of the analysis methods. The objective of this work is to present the potential of Petri nets in studies of Enterprise Modelling and Workflow, showing an example of application, with time and cost parameters.

Planning and Optimization of AGV Jobs by Petri Net and Genetic Algorithm

Directory of Open Access Journals (Sweden)

Anita Gudelj

2012-12-01

Full Text Available The following article presents the possibilities of job optimization on a maritime container terminal, in order to increase the system productivity and optimize the terminal capacity. Automated guided vehicles (AGVs are now becoming popular mode of container transport in seaport terminals. The moving of vehicles can be described as the set of discrete events and states. Some of these states can be undesirable such as conflicts and deadlocks. It is necessary to apply adequate control policy to avoid deadlocks and block the vehicles’ moving only in the case of dangerous situation.This paper addresses the use a Petri net as modeling and scheduling tool in this context. The aim of AGV scheduling is to dispatch a set of AGVs to improve the productivity of a system and reduce delay in a batch of pickup/drop-off jobs under certain constraints such as deadlines, priority, etc. The final goals are related to optimization of processing time and minimization of the number of AGVs involved while maintaining the system throughput.To find better solutions, the authors propose the integration MRF1 class of Petri net (MRF1PN with a genetic algorithm. Also, the use of a matrix based formal method is proposed to analyze discrete event dynamic system (DEDS. The algorithm is described to deal with multi-project, multi-constrained scheduling problem with shared resources. The developed model was tested and validated by simulation of typical scenarios of the container terminal of Port Koper. Modularity and simplicity of the approach allow using the model to monitor and test the efficiency of the processes, and also to propose future alternative solutions to optimize the schedule of operations and the employment of AGV at the terminal.

Control Design for Untimed Petri Nets Using Markov Decision Processes

Directory of Open Access Journals (Sweden)

Cherki Daoui

2017-01-01

Full Text Available Design of control sequences for discrete event systems (DESs has been presented modelled by untimed Petri nets (PNs. PNs are well-known mathematical and graphical models that are widely used to describe distributed DESs, including choices, synchronizations and parallelisms. The domains of application include, but are not restricted to, manufacturing systems, computer science and transportation networks. We are motivated by the observation that such systems need to plan their production or services. The paper is more particularly concerned with control issues in uncertain environments when unexpected events occur or when control errors disturb the behaviour of the system. To deal with such uncertainties, a new approach based on discrete time Markov decision processes (MDPs has been proposed that associates the modelling power of PNs with the planning power of MDPs. Finally, the simulation results illustrate the benefit of our method from the computational point of view. (original abstract

Efficient Data-Structures and Algorithms for a Coloured Petri Nets Simulator

DEFF Research Database (Denmark)

Mortensen, Kjeld Høyer

2001-01-01

In this paper we describe how efficient data-structures and algorithms are used to dramatically improve the performance of a simulator for Coloured Petri Nets compared with earlier versions. We have improved the simulator with respect to three areas: Firstly we have improved the transition...... of other transitions. Secondly we have improved the data-structures which hold multi-sets for markings. A kind of weight-balanced trees, called BB-trees. are used instead of lists as in the original version of the simulator. Although this kind of trees are more difficult to maintain at run...... "recipe" which is specially generated and optimised for each individual transition. The improved simulator is implemented in both the Design/CPN and CPN tools software packages, and has been used in several industrial projects....

Research and Application of FTA and Petri Nets in Fault Diagnosis in the Pantograph-Type Current Collector on CRH EMU Trains

Directory of Open Access Journals (Sweden)

Long-long Song

2015-01-01

Full Text Available A fault tree is established based on structural analysis, working principle analysis, and failure mode and effects analysis (FMEA of the pantograph-type current collector on the Chinese Rail High-Speed Electric Multiple Unit (CRH EMU train. To avoid the deficiencies of fault tree analysis (FTA, Petri nets modelling is used to address the problem of data explosion and carry out dynamic diagnosis. Relational matrix analysis is used to solve the minimal cut set equation of the fault tree. Based on the established state equation of the Petri nets, initial tokens and enable-transfer algorithms are used to express the fault transfer process mathematically and improve the efficiency of fault diagnosis inferences. Finally, using a practical fault diagnosis example for the pantographs on CRH EMU trains, the proposed method is proved to be reasonable and effective.

Application of Petri Nets in Bone Remodeling

Directory of Open Access Journals (Sweden)

Lingxi Li

2009-07-01

Full Text Available Understanding a mechanism of bone remodeling is a challenging task for both life scientists and model builders, since this highly interactive and nonlinear process can seldom be grasped by simple intuition. A set of ordinary differential equations (ODEs have been built for simulating bone formation as well as bone resorption. Although solving ODEs numerically can provide useful predictions for dynamical behaviors in a continuous time frame, an actual bone remodeling process in living tissues is driven by discrete events of molecular and cellular interactions. Thus, an event-driven tool such as Petri nets (PNs, which may dynamically and graphically mimic individual molecular collisions or cellular interactions, seems to augment the existing ODE-based systems analysis. Here, we applied PNs to expand the ODE-based approach and examined discrete, dynamical behaviors of key regulatory molecules and bone cells. PNs have been used in many engineering areas, but their application to biological systems needs to be explored. Our PN model was based on 8 ODEs that described an osteoprotegerin linked molecular pathway consisting of 4 types of bone cells. The models allowed us to conduct both qualitative and quantitative evaluations and evaluate homeostatic equilibrium states. The results support that application of PN models assists understanding of an event-driven bone remodeling mechanism using PN-specific procedures such as places, transitions, and firings.

Developmental switching in Physarum polycephalum : Petri net analysis of single cell trajectories of gene expression indicates responsiveness and genetic plasticity of the Waddington quasipotential landscape

International Nuclear Information System (INIS)

Werthmann, Britta; Marwan, Wolfgang

2017-01-01

The developmental switch to sporulation in Physarum polycephalum is a phytochrome-mediated far-red light-induced cell fate decision that synchronously encompasses the entire multinucleate plasmodial cell and is associated with extensive reprogramming of the transcriptome. By repeatedly taking samples of single cells after delivery of a light stimulus pulse, we analysed differential gene expression in two mutant strains and in a heterokaryon of the two strains all of which display a different propensity for making the cell fate decision. Multidimensional scaling of the gene expression data revealed individually different single cell trajectories eventually leading to sporulation. Characterization of the trajectories as walks through states of gene expression discretized by hierarchical clustering allowed the reconstruction of Petri nets that model and predict the observed behavior. Structural analyses of the Petri nets indicated stimulus- and genotype-dependence of both, single cell trajectories and of the quasipotential landscape through which these trajectories are taken. The Petri net-based approach to the analysis and decomposition of complex cellular responses and of complex mutant phenotypes may provide a scaffold for the data-driven reconstruction of causal molecular mechanisms that shape the topology of the quasipotential landscape. (paper)

Developmental switching in Physarum polycephalum: Petri net analysis of single cell trajectories of gene expression indicates responsiveness and genetic plasticity of the Waddington quasipotential landscape

Science.gov (United States)

Werthmann, Britta; Marwan, Wolfgang

2017-11-01

The developmental switch to sporulation in Physarum polycephalum is a phytochrome-mediated far-red light-induced cell fate decision that synchronously encompasses the entire multinucleate plasmodial cell and is associated with extensive reprogramming of the transcriptome. By repeatedly taking samples of single cells after delivery of a light stimulus pulse, we analysed differential gene expression in two mutant strains and in a heterokaryon of the two strains all of which display a different propensity for making the cell fate decision. Multidimensional scaling of the gene expression data revealed individually different single cell trajectories eventually leading to sporulation. Characterization of the trajectories as walks through states of gene expression discretized by hierarchical clustering allowed the reconstruction of Petri nets that model and predict the observed behavior. Structural analyses of the Petri nets indicated stimulus- and genotype-dependence of both, single cell trajectories and of the quasipotential landscape through which these trajectories are taken. The Petri net-based approach to the analysis and decomposition of complex cellular responses and of complex mutant phenotypes may provide a scaffold for the data-driven reconstruction of causal molecular mechanisms that shape the topology of the quasipotential landscape.

A Method for Modeling the Virtual Instrument Automatic Test System Based on the Petri Net

Institute of Scientific and Technical Information of China (English)

MA Min; CHEN Guang-ju

2005-01-01

Virtual instrument is playing the important role in automatic test system. This paper introduces a composition of a virtual instrument automatic test system and takes the VXIbus based a test software platform which is developed by CAT lab of the UESTC as an example. Then a method to model this system based on Petri net is proposed. Through this method, we can analyze the test task scheduling to prevent the deadlock or resources conflict. At last, this paper analyzes the feasibility of this method.

The application of coloured Petri nets to verification of distributed systems specified by message Sequence Charts

OpenAIRE

CHERNENOK S.A.; NEPOMNIASCHY V.A.

2015-01-01

The language of message sequence charts (MSC) is a popular scenario-based specification language used to describe the interaction of components in distributed systems. However, the methods for validation of MSC diagrams are underdeveloped. This paper describes a method for translation of MSC diagrams into coloured Petri nets (CPN). The method is applied to the property verification of these diagrams. The considered set of diagram elements is extended by the elements of UML sequence diagrams a...

A Concurrent Multiple Negotiation Protocol Based on Colored Petri Nets.

Science.gov (United States)

Niu, Lei; Ren, Fenghui; Zhang, Minjie; Bai, Quan

2017-11-01

Concurrent multiple negotiation (CMN) provides a mechanism for an agent to simultaneously conduct more than one negotiation. There may exist different interdependency relationships among these negotiations and these interdependency relationships can impact the outcomes of these negotiations. The outcomes of these concurrent negotiations contribute together for the agent to achieve an overall negotiation goal. Handling a CMN while considering interdependency relationships among multiple negotiations is a challenging research problem. This paper: 1) comprehensively highlights research problems of negotiations at concurrent negotiation level; 2) provides a graph-based CMN model with consideration of the interdependency relationships; and 3) proposes a colored Petri net-based negotiation protocol for conducting CMNs. With the proposed protocol, a CMN can be efficiently and concurrently processed and negotiation agreements can be efficiently achieved. Experimental results indicate the effectiveness and efficiency of the proposed protocol in terms of the negotiation success rate, the negotiation time and the negotiation outcome.

Verification of the safety communication protocol in train control system using colored Petri net

International Nuclear Information System (INIS)

Chen Lijie; Tang Tao; Zhao Xianqiong; Schnieder, Eckehard

2012-01-01

This paper deals with formal and simulation-based verification of the safety communication protocol in ETCS (European Train Control System). The safety communication protocol controls the establishment of safety connection between train and trackside. Because of its graphical user interface and modeling flexibility upon the changes in the system conditions, this paper proposes a composition Colored Petri Net (CPN) representation for both the logic and the timed model. The logic of the protocol is proved to be safe by means of state space analysis: the dead markings are correct; there are no dead transitions; being fair. Further analysis results have been obtained using formal and simulation-based verification approach. The timed models for the open transmit system and the application process are created for the purpose of performance analysis of the safety communication protocol. The models describe the procedure of data transmission and processing, and also provide relevant timed and stochastic factors, as well as time delay and lost packet, which may influence the time for establishment of safety connection of the protocol. Time for establishment of safety connection of the protocol in normal state is verified by formal verification, and then time for establishment of safety connection with different probability of lost packet is simulated. After verification it is found that the time for establishment of safety connection of the safety communication protocol satisfies the safety requirements.

Petri Net and Probabilistic Model Checking Based Approach for the Modelling, Simulation and Verification of Internet Worm Propagation.

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Misbah Razzaq

Full Text Available Internet worms are analogous to biological viruses since they can infect a host and have the ability to propagate through a chosen medium. To prevent the spread of a worm or to grasp how to regulate a prevailing worm, compartmental models are commonly used as a means to examine and understand the patterns and mechanisms of a worm spread. However, one of the greatest challenge is to produce methods to verify and validate the behavioural properties of a compartmental model. This is why in this study we suggest a framework based on Petri Nets and Model Checking through which we can meticulously examine and validate these models. We investigate Susceptible-Exposed-Infectious-Recovered (SEIR model and propose a new model Susceptible-Exposed-Infectious-Recovered-Delayed-Quarantined (Susceptible/Recovered (SEIDQR(S/I along with hybrid quarantine strategy, which is then constructed and analysed using Stochastic Petri Nets and Continuous Time Markov Chain. The analysis shows that the hybrid quarantine strategy is extremely effective in reducing the risk of propagating the worm. Through Model Checking, we gained insight into the functionality of compartmental models. Model Checking results validate simulation ones well, which fully support the proposed framework.

A PetriNet-Based Approach for Supporting Traceability in Cyber-Physical Manufacturing Systems.

Science.gov (United States)

Huang, Jiwei; Zhu, Yeping; Cheng, Bo; Lin, Chuang; Chen, Junliang

2016-03-17

With the growing popularity of complex dynamic activities in manufacturing processes, traceability of the entire life of every product has drawn significant attention especially for food, clinical materials, and similar items. This paper studies the traceability issue in cyber-physical manufacturing systems from a theoretical viewpoint. Petri net models are generalized for formulating dynamic manufacturing processes, based on which a detailed approach for enabling traceability analysis is presented. Models as well as algorithms are carefully designed, which can trace back the lifecycle of a possibly contaminated item. A practical prototype system for supporting traceability is designed, and a real-life case study of a quality control system for bee products is presented to validate the effectiveness of the approach.

Complexity Quantification for Overhead Transmission Line Emergency Repair Scheme via a Graph Entropy Method Improved with Petri Net and AHP Weighting Method

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Jing Zhou

2014-01-01

Full Text Available According to the characteristics of emergency repair in overhead transmission line accidents, a complexity quantification method for emergency repair scheme is proposed based on the entropy method in software engineering, which is improved by using group AHP (analytical hierarchical process method and Petri net. Firstly, information structure chart model and process control flowchart model could be built by Petri net. Then impact factors on complexity of emergency repair scheme could be quantified into corresponding entropy values, respectively. Finally, by using group AHP method, weight coefficient of each entropy value would be given before calculating the overall entropy value for the whole emergency repair scheme. By comparing group AHP weighting method with average weighting method, experiment results for the former showed a stronger correlation between quantified entropy values of complexity and the actual consumed time in repair, which indicates that this new method is more valid.

ertCPN: The adaptations of the coloured Petri-Net theory for real-time embedded system modeling and automatic code generation

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Wattanapong Kurdthongmee

2003-05-01

Full Text Available A real-time system is a computer system that monitors or controls an external environment. The system must meet various timing and other constraints that are imposed on it by the real-time behaviour of the external world. One of the differences between a real-time and a conventional software is that a real-time program must be both logically and temporally correct. To successfully design and implement a real-time system, some analysis is typically done to assure that requirements or designs are consistent and that they satisfy certain desirable properties that may not be immediately obvious from specification. Executable specifications, prototypes and simulation are particularly useful in real-time systems for debugging specifications. In this paper, we propose the adaptations to the coloured Petri-net theory to ease the modeling, simulation and code generation process of an embedded, microcontroller-based, real-time system. The benefits of the proposed approach are demonstrated by use of our prototype software tool called ENVisAge (an Extended Coloured Petri-Net Based Visual Application Generator Tool.

Simulation of the chemical stage in water radiolysis with the help of Continuous Petri nets

International Nuclear Information System (INIS)

Barilla, J.; Lokajíček, M.V.; Pisaková, H.; Simr, P.

2014-01-01

The final biological effect of ionizing particles may be influenced often strongly by some chemical substances present in cells during irradiation by low-LET radiation. It may occur during the chemical stage of the given process, due to chemical reactions of radicals running in the given process. However, the whole chemical process may be hardly described sufficiently with the help of the usual approach based on the deterministic diffusion-kinetic computations and the stochastic Monte-Carlo simulations. We have proposed already earlier a model describing the processes (i.e., the combined effect of cluster diffusion and chemical reactions) running in individual radical clusters that might be responsible for corresponding damages of DNA molecules (i.e., formation of DSBs). Now a further generalization of the given model (using Continuous Petri nets) will be presented that makes it possible to characterize more detailed behavior of individual radicals in corresponding clusters, which might be useful especially for low-LET radiation when individual radical clusters meet a DNA molecule at different time intervals after their formation; the decreasing presence of individual radicals in corresponding clusters being established. In this paper we shall focus on the design of the corresponding mathematical model and its application; the comparison of corresponding results with experimental data obtained in the case of deoxygenated system will be presented. - Highlights: • Creation of the mathematical model. • Realization of the model with the help of Continuous Petri nets. • Obtain the time dependence of changes in the concentration of radicals

The Perspective on Data and Control Flow Analysis in Topological Functioning Models by Petri Nets

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Asnina Erika

2014-12-01

Full Text Available The perspective on integration of two mathematical formalisms, i.e., Colored Petri Nets (CPNs and Topological Functioning Model (TFM, is discussed in the paper. The roots of CPNs are in modeling system functionality. The TFM joins principles of system theory and algebraic topology, and formally bridges the solution domain with the problem domain. It is a base for further automated construction of software design models. The paper discusses a perspective on check of control and data flows in the TFM by CPNs formalism. The research result is definition of mappings from TFMs to CPNs.

Extended object-oriented Petri net model for mission reliability simulation of repairable PMS with common cause failures

International Nuclear Information System (INIS)

Wu, Xin-yang; Wu, Xiao-Yue

2015-01-01

Phased Mission Systems (PMS) have several phases with different success criteria. Generally, traditional analytical methods need to make some assumptions when they are applied for reliability evaluation and analysis of complex PMS, for example, the components are non-repairable or components are not subjected to common cause failures (CCF). However, the evaluation and analysis results may be inapplicable when the assumptions do not agree with practical situation. In this article, we propose an extended object-oriented Petri net (EOOPN) model for mission reliability simulation of repairable PMS with CCFs. Based on object-oriented Petri net (OOPN), EOOPN defines four reusable sub-models to depict PMS at system, phase, or component levels respectively, logic transitions to depict complex components reliability logics in a more readable form, and broadcast place to transmit shared information among components synchronously. After extension, EOOPN could deal with repairable PMS with both external and internal CCFs conveniently. The mission reliability modelling, simulation and analysis using EOOPN are illustrated by a PMS example. The results demonstrate that the proposed EOOPN model is effective. - Highlights: • EOOPN model was effective in reliability simulation for repairable PMS with CCFs. • EOOPN had modular and hierarchical structure. • New elements of EOOPN made the modelling process more convenient and friendlier. • EOOPN had better model reusability and readability than other PNs

A PetriNet-Based Approach for Supporting Traceability in Cyber-Physical Manufacturing Systems

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Jiwei Huang

2016-03-01

Full Text Available With the growing popularity of complex dynamic activities in manufacturing processes, traceability of the entire life of every product has drawn significant attention especially for food, clinical materials, and similar items. This paper studies the traceability issue in cyber-physical manufacturing systems from a theoretical viewpoint. Petri net models are generalized for formulating dynamic manufacturing processes, based on which a detailed approach for enabling traceability analysis is presented. Models as well as algorithms are carefully designed, which can trace back the lifecycle of a possibly contaminated item. A practical prototype system for supporting traceability is designed, and a real-life case study of a quality control system for bee products is presented to validate the effectiveness of the approach.

A Petri net-based modelling of replacement strategies under technological obsolescence

Energy Technology Data Exchange (ETDEWEB)

Clavareau, Julien [Universite Libre de Bruxelles (U.L.B.), Service de Metrologie Nucleaire, Av. F.D. Roosevelt, 50 (CP165/84), Bruxelles B-1050 (Belgium)], E-mail: jclavare@ulb.ac.be; Labeau, Pierre-Etienne [Universite Libre de Bruxelles (U.L.B.), Service de Metrologie Nucleaire, Av. F.D. Roosevelt, 50 (CP165/84), Bruxelles B-1050 (Belgium)

2009-02-15

The technological obsolescence of a unit is characterised by the existence of challenger units displaying identical functionalities, but with higher performances. Though this issue is commonly encountered in practice, it has received little consideration in the literature. Previous exploratory works have treated the problem of replacing old-technology items by new ones, for identical components facing a unique new generation of items. This paper aims to define, in a realistic way, possible replacement policies when several types of challenger units are available and when the performances of these newly available units improve with time. Since no fully generic model can exist in maintenance optimisation, a modular modelling of the problem, allowing easy adaptations to features corresponding to specific applications is highly desirable. This work therefore proposes a modular Petri net model for this problem, underlying a Monte Carlo (MC) estimation of the costs incurred by the different possible replacement strategies under consideration.

Requirements Engineering for Reactive Systems: Coloured Petri Nets for an Elevator Controller

DEFF Research Database (Denmark)

Jørgensen, Jens Bæk; Fernandes, Joao Miguel; Tjell, Simon

2007-01-01

This paper presents a model-based approach to requirements engineering for reactive systems; we use an elevator controller as case study. We identify and justify two key properties that a model which we construct must have, namely: (1) controller-and-environment-partitioned, which means...... constituting a description of both the controller and the environment, and distinguishing between these two domains and between desired and assumed behaviour; (2) use case-based, which means constructed on the basis of a given use case diagram and reproducing the behaviour described in accompanying scenario...... descriptions. For the case study, we build an executable model in the formal modelling language Coloured Petri Nets. We demonstrate how this model is useful for requirements engineering, since it provides a solid basis for addressing behavioural issues early in the development process, for example regarding...

Fault detection and initial state verification by linear programming for a class of Petri nets

Science.gov (United States)

Rachell, Traxon; Meyer, David G.

1992-01-01

The authors present an algorithmic approach to determining when the marking of a LSMG (live safe marked graph) or a LSFC (live safe free choice) net is in the set of live safe markings M. Hence, once the marking of a net is determined to be in M, then if at some time thereafter the marking of this net is determined not to be in M, this indicates a fault. It is shown how linear programming can be used to determine if m is an element of M. The worst-case computational complexity of each algorithm is bounded by the number of linear programs necessary to compute.

Automatic Supervisory System Synthesis for Port Cranes Collision Prevention by Using Petri Net

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Danko Kezić

2006-05-01

Full Text Available The article deals with the system of port cranes comprisingtwo independently controlled cranes which are simultaneouslyengaged in the transhipment of cargo between a vessel and arailway wagon assembly alongside. The crane operator's errorcan lead to tlie collision of cranes. Therefore, it is necessary toinstall the supervisor in an automatic control system with thefunctions of continuous supervision of the process of cranemovement, and blocking of commands that can lead to collision.The article shows the method of crane system modellingas a discrete event system by using PIT and P-timed Petri nets.There is a proposal of a formal mathematic method for calculationof the state supervisor by P-invariant method. The supervisorcalculated in this way is maximally permissive supervisor.The efficiency of the supervisor is verified by a computer simulation.

Integrated logistic support studies using behavioral Monte Carlo simulation, supported by Generalized Stochastic Petri Nets

International Nuclear Information System (INIS)

Garnier, Robert; Chevalier, Marcel

2000-01-01

Studying large and complex industrial sites, requires more and more accuracy in modeling. In particular, when considering Spares, Maintenance and Repair / Replacement processes, determining optimal Integrated Logistic Support policies requires a high level modeling formalism, in order to make the model as close as possible to the real considered processes. Generally, numerical methods are used to process this kind of study. In this paper, we propose an alternate way to process optimal Integrated Logistic Support policy determination when dealing with large, complex and distributed multi-policies industrial sites. This method is based on the use of behavioral Monte Carlo simulation, supported by Generalized Stochastic Petri Nets. (author)

ePNK Applications and Annotations: A Simulator for YAWL Nets

DEFF Research Database (Denmark)

Kindler, Ekkart

2018-01-01

The ePNK is an Eclipse based platform and framework for developing and integrating Petri net tools and applications. New types of Petri nets can be realized and plugged into the ePNK without any programming by simply providing a model of the concepts of the new Petri net type. Moreover, the ePNK ...

Fuzzy colored petri nets and their application to efficient design and V and V of fuzzy logic controllers

International Nuclear Information System (INIS)

Son, Han Seong; Seong, Poong Hyun

1998-01-01

Generally, FLC design causes the designer to spend too much efforts and time. If a design support is provided to apply various membership functions to and simulate a FLC without coding at the early development stage, the cost problem may be solved to a remarkable degree. In order to offer the systematic approach to support FLC design, Fuzzy Colored Petri Nets (FCPN) is introduced as design support in this work. The feasibility of FCPN is demonstrated through a controller design example

Modeling of the chemical stage in water radiolysis using Petri nets

International Nuclear Information System (INIS)

Barilla, J; Simr, P; Lokajíček, M; Pisaková, H

2014-01-01

The biological effect of ionizing radiation is mediated practically always by the clusters of radicals formed by densely ionizing track ends of primary or secondary particles. In the case of low-LET radiation the direct effect may be practically neglected and the radical clusters meet a DNA molecule always some time after their formation. The corresponding damage effect (formation of DSB) depends then on the evolution running in individual clusters, being influenced by present chemical agents. Two main parallel processes influence then final effect: diffusion of corresponding radical clusters (lowering radical concentrations) and chemical reactions of all chemical substances present in the clusters. The processes running in the corresponding radical clusters will be modeled with the help of continuous Petri net, which enables us to study the concurrent influence of both the processes: lowering concentration of radicals due diffusion and due chemical reactions. The given model may be helpful especially when the effect of radicals on DSB formation (DNA damage) at the presence of different substances influencing radiobiological effect is to be studied

Fluid Petri Nets and hybrid model-checking: a comparative case study

International Nuclear Information System (INIS)

Gribaudo, M.; Horvath, A.; Bobbio, A.; Tronci, E.; Ciancamerla, E.; Minichino, M.

2003-01-01

The modeling and analysis of hybrid systems is a recent and challenging research area which is actually dominated by two main lines: a functional analysis based on the description of the system in terms of discrete state (hybrid) automata (whose goal is to ascertain conformity and reachability properties), and a stochastic analysis (whose aim is to provide performance and dependability measures). This paper investigates a unifying view between formal methods and stochastic methods by proposing an analysis methodology of hybrid systems based on Fluid Petri Nets (FPNs). FPNs can be analyzed directly using appropriate tools. Our paper shows that the same FPN model can be fed to different functional analyzers for model checking. In order to extensively explore the capability of the technique, we have converted the original FPN into languages for discrete as well as hybrid as well as stochastic model checkers. In this way, a first comparison among the modeling power of well known tools can be carried out. Our approach is illustrated by means of a 'real world' hybrid system: the temperature control system of a co-generative plant

Modelling and Analysing Deadlock in Flexible Manufacturing System using Timed Petri Net

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Assem Hatem Taha

2017-03-01

Full Text Available Flexible manufacturing system (FMS has several advantages compared to conventional systems such as higher machine utilization, higher efficiency, less inventory, and less production time. On the other hand, FMS is expensive and complicated. One of the main problems that may happen is the deadlock. Deadlock is a case that happens when one operation or more are unable to complete their tasks because of waiting of resources that are used by other processes. This may occur due to inappropriate sharing of the resources or improper resource allocation logic which may lead to deadlock occurrence due to the complexity of assigning shared resources to different tasks in an efficient way. One of the most effective tools to model and detect the deadlocks is the petri net. In this research the Matlab software has been used to detect the deadlock in two parallel lines with one shared machines. The analysis shows that deadlock exists at transition with high utilization and place with high waiting time

Design of Service Net based Correctness Verification Approach for Multimedia Conferencing Service Orchestration

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Cheng Bo

2012-02-01

Full Text Available Multimedia conferencing is increasingly becoming a very important and popular application over Internet. Due to the complexity of asynchronous communications and handle large and dynamically concurrent processes for multimedia conferencing, which confront relevant challenge to achieve sufficient correctness guarantees, and supporting the effective verification methods for multimedia conferencing services orchestration is an extremely difficult and challenging problem. In this paper, we firstly present the Business Process Execution Language (BPEL based conferencing service orchestration, and mainly focus on the service net based correction verification approach for multimedia conferencing services orchestration, which can automatically translated the BPEL based service orchestration into a corresponding Petri net model with the Petri Net Markup Language (PNML, and also present the BPEL service net reduction rules and multimedia conferencing service orchestration correction verification algorithms. We perform the correctness analysis and verification using the service net properties as safeness, reachability and deadlocks, and also provide an automated support tool for the formal analysis and soundness verification for the multimedia conferencing services orchestration scenarios. Finally, we give the comparison and evaluations.

PetriCode: A Tool for Template-Based Code Generation from CPN Models

DEFF Research Database (Denmark)

Simonsen, Kent Inge

2014-01-01

Code generation is an important part of model driven methodologies. In this paper, we present PetriCode, a software tool for generating protocol software from a subclass of Coloured Petri Nets (CPNs). The CPN subclass is comprised of hierarchical CPN models describing a protocol system at different...

Quasi-Steady-State Analysis based on Structural Modules and Timed Petri Net Predict System’s Dynamics: The Life Cycle of the Insulin Receptor

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Jennifer Scheidel

2015-12-01

Full Text Available The insulin-dependent activation and recycling of the insulin receptor play an essential role in the regulation of the energy metabolism, leading to a special interest for pharmaceutical applications. Thus, the recycling of the insulin receptor has been intensively investigated, experimentally as well as theoretically. We developed a time-resolved, discrete model to describe stochastic dynamics and study the approximation of non-linear dynamics in the context of timed Petri nets. Additionally, using a graph-theoretical approach, we analyzed the structure of the regulatory system and demonstrated the close interrelation of structural network properties with the kinetic behavior. The transition invariants decomposed the model into overlapping subnetworks of various sizes, which represent basic functional modules. Moreover, we computed the quasi-steady states of these subnetworks and demonstrated that they are fundamental to understand the dynamic behavior of the system. The Petri net approach confirms the experimental results of insulin-stimulated degradation of the insulin receptor, which represents a common feature of insulin-resistant, hyperinsulinaemic states.

Model to Counter the Threats in the Data Transmission System PLC-based Technology with the Use of Petri Nets

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A. A. Balaev

2010-06-01

Full Text Available In the article the most important aspects of information security technology Power Line Communica tions, namely the provision of conditions accessibility and integrity, are considered. It is shown that these aspects of the PLC-Technology has some internal “potential” counter, at least, such a widespread threat to both natural disturbances and/or artificial origin. The possibility of such an implementation using the simplified mathematical model of the PLC-based technologies of the theory of Petri nets is presented.

A Novel Petri Nets-Based Modeling Method for the Interaction between the Sensor and the Geographic Environment in Emerging Sensor Networks

Science.gov (United States)

Zhang, Feng; Xu, Yuetong; Chou, Jarong

2016-01-01

The service of sensor device in Emerging Sensor Networks (ESNs) is the extension of traditional Web services. Through the sensor network, the service of sensor device can communicate directly with the entity in the geographic environment, and even impact the geographic entity directly. The interaction between the sensor device in ESNs and geographic environment is very complex, and the interaction modeling is a challenging problem. This paper proposed a novel Petri Nets-based modeling method for the interaction between the sensor device and the geographic environment. The feature of the sensor device service in ESNs is more easily affected by the geographic environment than the traditional Web service. Therefore, the response time, the fault-tolerant ability and the resource consumption become important factors in the performance of the whole sensor application system. Thus, this paper classified IoT services as Sensing services and Controlling services according to the interaction between IoT service and geographic entity, and classified GIS services as data services and processing services. Then, this paper designed and analyzed service algebra and Colored Petri Nets model to modeling the geo-feature, IoT service, GIS service and the interaction process between the sensor and the geographic enviroment. At last, the modeling process is discussed by examples. PMID:27681730

A Novel Petri Nets-Based Modeling Method for the Interaction between the Sensor and the Geographic Environment in Emerging Sensor Networks

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Feng Zhang

2016-09-01

Full Text Available The service of sensor device in Emerging Sensor Networks (ESNs is the extension of traditional Web services. Through the sensor network, the service of sensor device can communicate directly with the entity in the geographic environment, and even impact the geographic entity directly. The interaction between the sensor device in ESNs and geographic environment is very complex, and the interaction modeling is a challenging problem. This paper proposed a novel Petri Nets-based modeling method for the interaction between the sensor device and the geographic environment. The feature of the sensor device service in ESNs is more easily affected by the geographic environment than the traditional Web service. Therefore, the response time, the fault-tolerant ability and the resource consumption become important factors in the performance of the whole sensor application system. Thus, this paper classified IoT services as Sensing services and Controlling services according to the interaction between IoT service and geographic entity, and classified GIS services as data services and processing services. Then, this paper designed and analyzed service algebra and Colored Petri Nets model to modeling the geo-feature, IoT service, GIS service and the interaction process between the sensor and the geographic enviroment. At last, the modeling process is discussed by examples.

Can I find a partner? Undecidability of partner existence for open nets

NARCIS (Netherlands)

Massuthe, P.; Serebrenik, A.; Sidorova, N.; Wolf, K.

2008-01-01

We study open nets as Petri net models of web services, with a link to the practically relevant language WS-BPEL. For those nets, we investigate the problem of operability which we consider as fundamental as the successful notion of soundness for workflow nets, i.e., Petri net models of business

Petri Nets Based Modelling of Control Flow for Memory-Aid Interactive Programs in Telemedicine

CERN Document Server

Khoromskaia, V K

2004-01-01

Petri Nets (PN) based modelling of the control flow for the interactive memory assistance programs designed for personal pocket computers and having special requirements for robustness is considered. The proposed concept allows one to elaborate the programs which can give users a variety of possibilities for a day-time planning in the presence of environmental and time restrictions. First, a PN model for a known simple algorithm is constructed and analyzed using the corresponding state equations and incidence matrix. Then a PN graph for a complicated algorithm with overlapping actions and choice possibilities is designed, supplemented by an example of its analysis. Dynamic behaviour of this graph is tested by tracing of all possible paths of the flow of control using the PN simulator. It is shown that PN based modelling provides reliably predictable performance of interactive algorithms with branched structures and concurrency requirements.

Model petri net of adaptive traffic lights and its collaboration with a special event

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Tristono Tomi

2018-01-01

Full Text Available Traffic lights have an important role as the system control of vehicles flow on the urban network. Commonly, most countries still using fixed time strategy. Our research proposes the adaptive traffic lights model to response the traffic demand. It uses basic Petri net as a general modeling framework. Foractuating method of minimum and maximum green signal time interval, the green traffic lights have three-time extension units. Next, we collaborate on a case of the existence of railways that crosses on the southern arm of an intersection. We introduce both of collaboration model design of traffic lights and the railway's gate which always closes while a train passing. Verification and validation of the model are based on the simulation result of vehicles queue. The collaboration model design of traffic lights has excellent performance, and it can resolve the congestion problem better than conventional schedule.

Fast substation service restoration using intelligent petri-nets models

Energy Technology Data Exchange (ETDEWEB)

Yang, H.T.; Peng, P.C.; Jiang, H.L. [Chung Yuan Christian Univ., Chung Li, Taiwan (China)

2006-07-01

Service restoration of a substation is a stressful and immediate task that must be conducted by system operators following a blackout. Operators, including those of Taiwan Power Company (TPC), normally restore power loads on the basis of their past experiences and engineering heuristics. Due to the significant number of switching operations to be evaluated, a computer-aided decision support system can be quite valuable. In distribution system automation, installation of unmanned substations requires an automated restoration computer system to rapidly devise a switching plan after a fault event. The modeling technique of Petri Nets (PNs) encompasses fault diagnosis of distribution systems, protective scheming of relays, and generic restoration schedule of power transmission systems. Knowledge or configuration about the system concerned can be expressed systematically through a structured model with parallelism and synchronization. This paper proposed a new PNs knowledge representation scheme to achieve a fast, on-line service restoration plan of a substation. The paper described the task of service restoration in a substation as well as the heuristic rules adopted by the dispatchers of the TPC distribution systems. The paper also introduced the topic of Typical PN properties and the proposed matrix operations for PNs reasoning. The proposed basic PNs model for service restoration on the basis of the engineering heuristics were also identified. It was concluded that the proposed approach not only facilitated software programming, but was highly adaptive to the extension or maintenance of the developed programs, arising from the changes of the substation configuration. 18 refs., 1 tab., 8 figs.

Server consolidation for heterogeneous computer clusters using Colored Petri Nets and CPN Tools

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Issam Al-Azzoni

2015-10-01

Full Text Available In this paper, we present a new approach to server consolidation in heterogeneous computer clusters using Colored Petri Nets (CPNs. Server consolidation aims to reduce energy costs and improve resource utilization by reducing the number of servers necessary to run the existing virtual machines in the cluster. It exploits the emerging technology of live migration which allows migrating virtual machines between servers without stopping their provided services. Server consolidation approaches attempt to find migration plans that aim to minimize the necessary size of the cluster. Our approach finds plans which not only minimize the overall number of used servers, but also minimize the total data migration overhead. The latter objective is not taken into consideration by other approaches and heuristics. We explore the use of CPN Tools in analyzing the state spaces of the CPNs. Since the state space of the CPN model can grow exponentially with the size of the cluster, we examine different techniques to generate and analyze the state space in order to find good plans to server consolidation within acceptable time and computing power.

Diagnosis of Intermittent Faults in IGBTs Using the Latent Nestling Method with Hybrid Coloured Petri Nets

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Leonardo Rodriguez-Urrego

2015-01-01

Full Text Available This paper presents a fault diagnosis application of the Latent Nestling Method to IGBTs. The paper extends the Latent Nestling Method based in Coloured Petri Nets (CPNs to hybrid systems in such a manner that IGBTs performance can be modeled. CPNs allow for an enhanced capability for synthesis and modeling in contrast to the classical phenomena of combinational state explosion when Finite State Machine methods are applied. We present an IGBT model with different fault modes including those of intermittent nature that can be used advantageously as predictive symptoms within a predictive maintenance strategy. Ageing stress tests have been experimentally applied to the IGBTs modules and intermittent faults are diagnosed as precursors of permanent failures. In addition, ageing is validated with morphological analysis (Scanning Electron Microscopy and semiqualitative analysis (Energy Dispersive Spectrometry.

Development of automated operating procedure system using fuzzy colored petri nets for nuclear power plants

International Nuclear Information System (INIS)

Lee, Seung Jun; Seong, Poong Hyun

2004-01-01

In this work, AuTomated Operating Procedure System (ATOPS) is developed. ATOPS is an automation system for emergency operation of a nuclear power plant (NPP) and it can monitor signals, diagnose statuses, and generate control actions according to corresponding operating procedures without any human operator's help. Main functions of ATOPS are an anomaly detection function and a procedure execution function but only the procedure execution function is implemented in this work because this work is just the first step. In the procedure execution function, operating procedures of NPPs are analyzed and modeled using Fuzzy Colored Petri Nets (FCPN) and executed depending on decision making of the inference engine. In this work, ATOPS prototype is developed to demonstrate its feasibility and it is also validated using the FISA-2/WS simulator. The validation is performed for the cases of a loss of coolant accident (LOCA) and a steam generator tube rupture (SGTR). The simulation results show that ATOPS works correctly in the emergency situations

Solving Flexible Job-Shop Scheduling Problem Using Gravitational Search Algorithm and Colored Petri Net

Directory of Open Access Journals (Sweden)

Behnam Barzegar

2012-01-01

Full Text Available Scheduled production system leads to avoiding stock accumulations, losses reduction, decreasing or even eliminating idol machines, and effort to better benefitting from machines for on time responding customer orders and supplying requested materials in suitable time. In flexible job-shop scheduling production systems, we could reduce time and costs by transferring and delivering operations on existing machines, that is, among NP-hard problems. The scheduling objective minimizes the maximal completion time of all the operations, which is denoted by Makespan. Different methods and algorithms have been presented for solving this problem. Having a reasonable scheduled production system has significant influence on improving effectiveness and attaining to organization goals. In this paper, new algorithm were proposed for flexible job-shop scheduling problem systems (FJSSP-GSPN that is based on gravitational search algorithm (GSA. In the proposed method, the flexible job-shop scheduling problem systems was modeled by color Petri net and CPN tool and then a scheduled job was programmed by GSA algorithm. The experimental results showed that the proposed method has reasonable performance in comparison with other algorithms.

Design method of control system for HTGR fuel handling process with control Petri net

International Nuclear Information System (INIS)

Han Zandong; Luo Sheng; Liu Jiguo

2008-01-01

As a complex mechanical system,the fuel handling system (FHS) of pebble-bed high temperature gas cooled reactor (HTGR) is with the features of complicated structure, numerous control devices and strict working scheduling. It is very important to precisely describe the function of FHS and effectively design its control system. A design method of control system based on control Petri net (CPN) is introduced in this paper. By associating outputs and operations with places, associating inputs and conditions with transitions, and introducing macro-places and macro-actions, the CPN realizes hierarchy design of complex control system. Based on the analysis of basic functions and working flow of FHS, its control system is described and designed by CPN. According to the firing regulation of transition,the designed CPN can be easily converted into LAD program of PLC, which can be implemented on the FHS simulating control test-bed. Application illuminates that proposed method has the advantages of clear design structure, exact description power and effective design ability of control program, which can meet the requirements of FHS control sys-tem design. (authors)

Scheduling of Crude Oil Operations in Refinery without Sufficient Charging Tanks Using Petri Nets

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Yan An

2017-05-01

Full Text Available A short-term schedule for crude oil operations in a refinery should define and sequence the activities in detail. Each activity involves both discrete-event and continuous variables. The combinatorial nature of the scheduling problem makes it difficult to solve. For such a scheduling problem, charging tanks are a type of critical resources. If the number of charging tanks is not sufficient, the scheduling problem is further complicated. This work conducts a study on the scheduling problem of crude oil operations without sufficient charging tanks. In this case, to make a refinery able to operate, a charging tank has to be in simultaneous charging and feeding to a distiller for some time, called simultaneously-charging-and-feeding (SCF mode, leading to disturbance to the oil distillation in distillers. A hybrid Petri net model is developed to describe the behavior of the system. Then, a scheduling method is proposed to find a schedule such that the SCF mode is minimally used. It is computationally efficient. An industrial case study is given to demonstrate the obtained results.

Verification of a primary-to-secondary leaking safety procedure in a nuclear power plant using coloured Petri nets

International Nuclear Information System (INIS)

Nemeth, E.; Bartha, T.; Fazekas, Cs.; Hangos, K.M.

2009-01-01

This paper deals with formal and simulation-based verification methods of a PRImary-to-SEcondary leaking (abbreviated as PRISE) safety procedure. The PRISE safety procedure controls the draining of the contaminated water in a faulty steam generator when a non-compensable leaking from the primary to the secondary circuit occurs. Because of the discrete nature of the verification, a Coloured Petri Net (CPN) representation is proposed for both the procedure and the plant model. We have proved by using a non-model-based strategy that the PRISE safety procedure is safe, there are no dead markings in the state space, and all transitions are live; being either impartial or fair. Further analysis results have been obtained using a model-based verification approach. We created a simple, low dimensional, nonlinear dynamic model of the primary circuit in a VVER-type pressurized water nuclear power plant for the purpose of the model-based verification. This is in contrast to the widely used safety analysis that requires an accurate detailed model. Our model also describes the relevant safety procedures, as well as all of the major leaking-type faults. We propose a novel method to transform this model to a CPN form by discretization. The composed plant and PRISE safety procedure system has also been analysed by simulation using CPN analysis tools. We found by the model-based analysis-using both single and multiple faults-that the PRISE safety procedure initiates the draining when the PRISE event occurs, and no false alarm will be initiated

Designing Tool Support for Translating Use Cases and UML 2.0 Sequence Diagrams into a Coloured Petri Net

DEFF Research Database (Denmark)

Fernandes, Joao Miguel; Tjell, Simon; Jørgensen, Jens Bæk

2007-01-01

On a case study on the specification of an elevator controller, this paper presents an approach that can translate given UML descriptions into a Coloured Petri Net (CPN) model. The UML descriptions must be specified in the form of Use Cases (UCs) and UML 2.0 Sequence Diagrams (SDs). The CPN model...... constitutes one single, coherent and executable representation of all possible behaviours that are specified by the given UML artefacts. CPN is a formal modelling language that enables construction and analysis of scalable, executable models of behaviour. A combined use of UML and CPN can be useful in several...... projects. CPN is well supported by the tool called CPN Tools and the work we present here is aimed at building a CPN Tools front-end engine that implements the proposed translation....

Modelling and Analysis of the Feeding Regimen Induced Entrainment of Hepatocyte Circadian Oscillators Using Petri Nets

Science.gov (United States)

Tareen, Samar Hayat Khan; Ahmad, Jamil

2015-01-01

Circadian rhythms are certain periodic behaviours exhibited by living organism at different levels, including cellular and system-wide scales. Recent studies have found that the circadian rhythms of several peripheral organs in mammals, such as the liver, are able to entrain their clocks to received signals independent of other system level clocks, in particular when responding to signals generated during feeding. These studies have found SIRT1, PARP1, and HSF1 proteins to be the major influencers of the core CLOCKBMAL1:PER-CRY circadian clock. These entities, along with abstracted feeding induced signals were modelled collectively in this study using Petri Nets. The properties of the model show that the circadian system itself is strongly robust, and is able to continually evolve. The modelled feeding regimens suggest that the usual 3 meals/day and 2 meals/day feeding regimens are beneficial with any more or less meals/day negatively affecting the system. PMID:25789928

Development of an automated operating procedure system using fuzzy colored petri nets for nuclear power plants

International Nuclear Information System (INIS)

Lee, Seung Jun; Seong, Poong Hyun

2002-01-01

In this work, AuTomated Operating Procedure System (ATOPS) is developed. ATOPS is an automation system for operation of a nuclear power plant (NPP) which can monitor signals, diagnose statuses, and generate control actions according to corresponding operating procedures, without any human operator's help. Main functions of ATOPS are anomaly detection function and procedure execution function, but only the procedure execution function is implemented because this work is just the first step. In the procedure execution function, operating procedures of NPP are analyzed and modeled using Fuzzy Colored Petri Nets (FCPN), and executed depending on decision making of the inference engine. In this work, an ATOPS prototype is developed in order to demonstrate its feasibility and it is also validated using FISA-2/WS simulator. The validation is performed for the cases of a loss of coolant accident (LOCA) and a steam generator tube rupture (SGTR). The simulation results show that ATOPS works correctly in the emergency situations

Modelling and analysis of the feeding regimen induced entrainment of hepatocyte circadian oscillators using petri nets.

Directory of Open Access Journals (Sweden)

Samar Hayat Khan Tareen

Full Text Available Circadian rhythms are certain periodic behaviours exhibited by living organism at different levels, including cellular and system-wide scales. Recent studies have found that the circadian rhythms of several peripheral organs in mammals, such as the liver, are able to entrain their clocks to received signals independent of other system level clocks, in particular when responding to signals generated during feeding. These studies have found SIRT1, PARP1, and HSF1 proteins to be the major influencers of the core CLOCKBMAL1:PER-CRY circadian clock. These entities, along with abstracted feeding induced signals were modelled collectively in this study using Petri Nets. The properties of the model show that the circadian system itself is strongly robust, and is able to continually evolve. The modelled feeding regimens suggest that the usual 3 meals/day and 2 meals/day feeding regimens are beneficial with any more or less meals/day negatively affecting the system.

Application of modified Martinez-Silva algorithm in determination of net cover

Science.gov (United States)

Stefanowicz, Łukasz; Grobelna, Iwona

2016-12-01

In the article we present the idea of modifications of Martinez-Silva algorithm, which allows for determination of place invariants (p-invariants) of Petri net. Their generation time is important in the parallel decomposition of discrete systems described by Petri nets. Decomposition process is essential from the point of view of discrete system design, as it allows for separation of smaller sequential parts. The proposed modifications of Martinez-Silva method concern the net cover by p-invariants and are focused on two important issues: cyclic reduction of invariant matrix and cyclic checking of net cover.

Analysis and Verification of Message Sequence Charts of Distributed Systems with the Help of Coloured Petri Nets

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S. A. Chernenok

2014-01-01

Full Text Available The standard language of message sequence charts MSC is intended to describe scenarios of object interaction. Due to their expressiveness and simplicity MSC diagrams are widely used in practice at all stages of system design and development. In particular, the MSC language is used for describing communication behavior in distributed systems and communication protocols. In this paper the method for analysis and verification of MSC and HMSC diagrams is considered. The method is based on the translation of (HMSC into coloured Petri nets. The translation algorithms cover most standard elements of the MSC including data concepts. Size estimates of the CPN which is the result of the translation are given. Properties of the resulting CPN are analyzed and verified by using the known system CPN Tools and the CPN verifier based on the known tool SPIN. The translation method has been demonstrated by the example.

Translating Colored Control Flow Nets into Readable Java via Annotated Java Workflow Nets

DEFF Research Database (Denmark)

Lassen, Kristian Bisgaard; Tjell, Simon

2007-01-01

In this paper, we present a method for developing Java applications from Colored Control Flow Nets (CCFNs), which is a special kind of Colored Petri Nets (CPNs) that we introduce. CCFN makes an explicit distinction between the representation of: The system, the environment of the system, and the ......In this paper, we present a method for developing Java applications from Colored Control Flow Nets (CCFNs), which is a special kind of Colored Petri Nets (CPNs) that we introduce. CCFN makes an explicit distinction between the representation of: The system, the environment of the system......, and the interface between the system and the environment. Our translation maps CCFNs into Anno- tated Java Workflow Nets (AJWNs) as an intermediate step, and these AJWNs are finally mapped to Java. CCFN is intended to enforce the modeler to describe the system in an imperative manner which makes the subsequent...... translation to Java easier to define. The translation to Java preserves data dependencies and control-flow aspects of the source CCFN. This paper contributes to the model-driven software development paradigm, by showing how to model a system, environment, and their interface, as a CCFN and presenting a fully...

Facilitating the Practical Use of Coloured Petri Nets

DEFF Research Database (Denmark)

Lindstrøm, Bo

This dissertation is to investigate and advance tools for practical use of CP-nets. This includes development of facilities for creating domain-specific graphical user interfaces, a proposal for facilities for including auxiliary information in a CP-net without modifying the CP-net itself...

Tools and Methods for RTCP-Nets Modeling and Verification

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Szpyrka Marcin

2016-09-01

Full Text Available RTCP-nets are high level Petri nets similar to timed colored Petri nets, but with different time model and some structural restrictions. The paper deals with practical aspects of using RTCP-nets for modeling and verification of real-time systems. It contains a survey of software tools developed to support RTCP-nets. Verification of RTCP-nets is based on coverability graphs which represent the set of reachable states in the form of directed graph. Two approaches to verification of RTCP-nets are considered in the paper. The former one is oriented towards states and is based on translation of a coverability graph into nuXmv (NuSMV finite state model. The later approach is oriented towards transitions and uses the CADP toolkit to check whether requirements given as μ-calculus formulae hold for a given coverability graph. All presented concepts are discussed using illustrative examples

Maximal Conflict Set Enumeration Algorithm Based on Locality of Petri Nets%基于Pe tri网局部性的极大冲突集枚举算法

Institute of Scientific and Technical Information of China (English)

潘理; 郑红; 刘显明; 杨勃

2016-01-01

冲突是Petri网研究的重要主题。目前Petri网冲突研究主要集中于冲突建模和冲突消解策略，而对冲突问题本身的计算复杂性却很少关注。提出Petri网的冲突集问题，并证明冲突集问题是NP（Non-deterministic Polyno-mial）完全的。提出极大冲突集动态枚举算法，该算法基于当前标识的所有极大冲突集，利用Petri网实施局部性，仅计算下一标识中受局部性影响的极大冲突集，从而避免重新枚举所有极大冲突集。该算法时间复杂度为O（m2 n），m是当前标识的极大冲突集数目，n是变迁数。最后证明自由选择网、非对称选择网的极大冲突集枚举算法复杂度可降至O（n2）。极大冲突集枚举算法研究将为Petri网冲突问题的算法求解提供理论参考。%Conflict is an essential concept in Petri net theory.The existing research focuses on the modelling and resolu-tion strategies of conflict problems,but less on the computational complexity of the problems theirselves.In this paper,we pro-pose the conflict set problem for Petri nets,and prove that the conflict set problem is NP-complete.Furthermore,we present a dynamic algorithm for the maximal conflict set enumeration.Our algorithm only computes those conflict sets that are affected by local firing,which avoids enumerating all maximal conflict sets at each marking.The algorithm needs time O(m2n)where m is the number of maximal conflict sets at the current marking and n is the number of transitions.Finally,we show that the maximal conflict set enumeration problem can be solved in O(n2)for free-choice nets and asymmetric choice nets.The results on complexity of thel conflict set problem provide a theoretical reference for solving conflict problems of Petri nets.

The methodology of multicriterial assessment of Petri nets’ apparatus

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Pashchenko Dmitry

2016-01-01

Full Text Available This article emphasizes the effectiveness and relevance of the using of the apparatus of Petri nets for modeling of complex computing systems. Due to the fact that the methods of analysis existing in this theory do not allow estimating the resources required to build the desired model of the system, there is a problem of shortage of criteria for its evaluation in terms of the complexity of the construction. In the article we consider the method of analysis of a random Petri net based on the complexity of its building and relationships of internal units - subnets. The purpose of this article is a software implementation of such an assessment within the theory of PN structures. Due to the fact, that structural approach allows to perform the operation of decomposition of the original system, this model can be divided into subnets of minimal dimension, that will allow to make its quantitative assessment - ranking. To determine the total assessment of the input and output data of the system we will perform the analysis of head and tail positions of the net taking into account the weights of the input and output arcs of these positions. In order to identify an extent of the cost required to build the system, the number of operations of union of subnet transitions and positions. These subnets have minimal dimension in the original PN. Thus, the article demonstrates the formal implementation of assessment technique modules with using of algebra of sets, and the rules of splitting the PN structure into elementary blocks are formulated. The example of a comparative assessment of the two Petri nets based on the proposed complexity criteria is given; the plots of PN in different coordinate systems are displayed. The article presents the results of the research - a plot of PN structures in three-dimensional space, implemented using described software. It demonstrates the accuracy of PN assessment by structural analysis in comparing with a non

Cognitive modelling with Coloured Petri Nets for the analysis of human behaviour; Kognitive Modellierung mit farbigen Petrinetzen zur Analyse menschlichen Verhaltens

Energy Technology Data Exchange (ETDEWEB)

Werther, B.

2006-07-01

The thesis presents a model based approach for a holistic consideration of human-machine systems. The model supports the design and formation of the operator's work sequences. In scope of the thesis a Formal Cognitive Resource (FCR)-Model is developed which treats limitation of the human operators processing capability as a main property. From this limitation stems the need to integrate and organize different action sequences into a balanced working process. The model is implemented as a Coloured Petri Net. Typical characteristics of net components find inherent consideration in the FCR-Model. In a first validation example behaviour of the FCR-Model is analyzed and compared with empirical results obtained in an experimental study performed on the operation of a micro world. Reasons for a specific behaviour of human operators in a working environment are being identified depending on cognitive parameters of the FCR-Model. It is shown how these parameters correspond to psychological performance properties. The FCR-Model is its current version serves for analysis of human information processing and discloses critical situations and faults in human behaviour. (Orig.)

SafeNet: a methodology for integrating general-purpose unsafe devices in safe-robot rehabilitation systems.

Science.gov (United States)

Vicentini, Federico; Pedrocchi, Nicola; Malosio, Matteo; Molinari Tosatti, Lorenzo

2014-09-01

Robot-assisted neurorehabilitation often involves networked systems of sensors ("sensory rooms") and powerful devices in physical interaction with weak users. Safety is unquestionably a primary concern. Some lightweight robot platforms and devices designed on purpose include safety properties using redundant sensors or intrinsic safety design (e.g. compliance and backdrivability, limited exchange of energy). Nonetheless, the entire "sensory room" shall be required to be fail-safe and safely monitored as a system at large. Yet, sensor capabilities and control algorithms used in functional therapies require, in general, frequent updates or re-configurations, making a safety-grade release of such devices hardly sustainable in cost-effectiveness and development time. As such, promising integrated platforms for human-in-the-loop therapies could not find clinical application and manufacturing support because of lacking in the maintenance of global fail-safe properties. Under the general context of cross-machinery safety standards, the paper presents a methodology called SafeNet for helping in extending the safety rate of Human Robot Interaction (HRI) systems using unsafe components, including sensors and controllers. SafeNet considers, in fact, the robotic system as a device at large and applies the principles of functional safety (as in ISO 13489-1) through a set of architectural procedures and implementation rules. The enabled capability of monitoring a network of unsafe devices through redundant computational nodes, allows the usage of any custom sensors and algorithms, usually planned and assembled at therapy planning-time rather than at platform design-time. A case study is presented with an actual implementation of the proposed methodology. A specific architectural solution is applied to an example of robot-assisted upper-limb rehabilitation with online motion tracking. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Reduction rules for reset/inhibitor nets

NARCIS (Netherlands)

Verbeek, H.M.W.; Wynn, M.T.; Aalst, van der W.M.P.; Hofstede, ter A.H.M.

2010-01-01

Reset/inhibitor nets are Petri nets extended with reset arcs and inhibitor arcs. These extensions can be used to model cancellation and blocking. A reset arc allows a transition to remove all tokens from a certain place when the transition fires. An inhibitor arc can stop a transition from being

The effect of cigarette smoking on endothelial damage and atherosclerosis development – modeled and analyzed using Petri nets

Directory of Open Access Journals (Sweden)

Chmielewska Kaja

2017-06-01

Full Text Available Atherosclerosis as one of the crucial causes of cardiovascular diseases (CVD is the leading reason of death worldwide. One of the contributing factors to this phenomenon is endothelial dysfunction, which is associated with the impact of various agents and their interactions. Tobacco smoke is one of the well known factors here. For better understanding of its significance a model of its impact on atherosclerotic plaque formation has been proposed. The model contains selected aspects of the influence of tobacco smoke, dual function of nitric oxide (NO (influence of various mechanisms on NO bioavailability, oxidative stress which promotes low density lipoproteins oxidation, macrophages significance and other mechanisms leading to an aggravation of the endothelial disturbances. The model has been built using Petri nets theory and the analysis has been based on t-invariants. This approach allowed to confirm the important role of inflammation and oxidative stress in atherosclerosis development and moreover it has shown the considerable influence of the cigarette smoke.

A livelock control policy for a flexible manufacturing system modeling with a subclass of generalized Petri nets

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C.Q. Hou

2014-12-01

Full Text Available Livelocks, like deadlocks, can result in the serious problems in running process of flexible manufacturing systems (FMSs as well. Current deadlock control policies based on the approaches of siphon detection and control, cannot cope with livelocks in a system of sequential systems with shared resources (S4R, a typical subclass of Petri nets that can model FMSs. On the basis of the mixed integer programming method, this study proposes a livelock control policy (LCP that can not only solve the new smart siphons (NSSs associated with livelocks or deadlocks in an S4R system directly, but also make the solved NSSs max′-controlled by adding the corresponding control places (CPs. As a result, an original S4R system with livelocks or deadlocks can be turned into the live controlled one in which no NSSs can be found. The related theoretical analysis and several examples are given to demonstrate the proposed LCP. Compared with the existing methods in the literature, the proposed one is more general and powerful.

Modeling Message Queueing Services with Reliability Guarantee in Cloud Computing Environment Using Colored Petri Nets

Directory of Open Access Journals (Sweden)

Jing Li

2015-01-01

Full Text Available Motivated by the need for loosely coupled and asynchronous dissemination of information, message queues are widely used in large-scale application areas. With the advent of virtualization technology, cloud-based message queueing services (CMQSs with distributed computing and storage are widely adopted to improve availability, scalability, and reliability; however, a critical issue is its performance and the quality of service (QoS. While numerous approaches evaluating system performance are available, there is no modeling approach for estimating and analyzing the performance of CMQSs. In this paper, we employ both the analytical and simulation modeling to address the performance of CMQSs with reliability guarantee. We present a visibility-based modeling approach (VMA for simulation model using colored Petri nets (CPN. Our model incorporates the important features of message queueing services in the cloud such as replication, message consistency, resource virtualization, and especially the mechanism named visibility timeout which is adopted in the services to guarantee system reliability. Finally, we evaluate our model through different experiments under varied scenarios to obtain important performance metrics such as total message delivery time, waiting number, and components utilization. Our results reveal considerable insights into resource scheduling and system configuration for service providers to estimate and gain performance optimization.

Petri Net Approach of Collision Prevention Supervisor Design in Port Transport System

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Danko Kezić

2007-09-01

Full Text Available Modern port terminals are equipped with various localtransport systems, which have the main task to transport cargobetween local storehouses and transport resources (ships,trains, trucks in the fastest and most efficient way, and at thelowest possible cost. These local transport systems consist offully automated transport units (AGV- automatic guided vehiclewhich are controlled by the computer system. The portcomputer system controls the fully automated transport units inthe way to avoid possible deadlocks and collisions betweenthem. However, beside the fully automated local transportunits, there are human operated transport units (fork-lifttrucks, cranes etc. which cross the path oftheAGVfrom timeto time. The collision of human operated transp011 unit andA GV is possible due to human inattention. To solve this problem,it is necesswy to design a supe1vismy control system thatcoordinates and controls both human driven transport unit andA G V In other words, the human-machine interactions need tobe supen·ised. The supen•ising system can be realized in the waythat the port terminal is divided into zones. Vehicle movementsare supen•ised by a video system which detects the moving ofparticular l'ehicles as a discrete event. Based on detected events,dangerous moving of certain vehicles is blocked by the supe1visi11gsystem. The paper considers the design of collision preventionsupen•isor by using discrete event dynamic themy. The portterminal is modeled by using ordi1za1y Petri nets. The design ofcollision prevention supe1visor is cmTied out by using the P-inl'ariantmethod. The verification of the supervisor is done bycomputer simulation.

Online Open Circuit Fault Diagnosis for Rail Transit Traction Converter Based on Object-Oriented Colored Petri Net Topology Reasoning

Directory of Open Access Journals (Sweden)

Lei Wang

2016-01-01

Full Text Available For online open circuit fault diagnosis of the traction converter in rail transit vehicles, conventional approaches depend heavily on component parameters and circuit layouts. For better universality and less parameter sensitivity during the diagnosis, this paper proposes a novel topology analysis approach to diagnose switching device open circuit failures. During the diagnosis, the topology is analyzed with fault reasoning mechanism, which is based on object-oriented Petri net (OOCPN. The OOCPN model takes in digitalized current inputs as fault signatures, and dynamical transitions between discrete switching states of a circuit with broken device are symbolized with the dynamical transitions of colored tokens in OOCPN. Such transitions simulate natural reasoning process of an expert’s brain during diagnosis. The dependence on component parameters and on circuit layouts is finally eliminated by such circuit topology reasoning process. In the last part, the proposed online reasoning and diagnosis process is exemplified with the case of a certain switching device failure in the power circuit of traction converter.

Flinders Petrie and Eugenics at UCL

Directory of Open Access Journals (Sweden)

Kathleen L. Sheppard

2010-05-01

Full Text Available William Matthew Flinders Petrie is considered the father of scientific archaeology and is credited with developing a chronology of Ancient Egypt using the nondescript artefacts that other archaeologists had ignored. He occupied the first chair of Egyptology in England, and was also well-known for the museum built around his personal collection of Egyptian artifacts at University College London. Petrie's archaeological work has been studied by scholars, from various disciplines, for its scholarly, cultural, and historical value, while Petrie's life and career outside of archaeology have been the subject of relatively little study. Petrie himself wrote two life stories: the first, 'Ten Years Digging in Egypt, 1881–1891' (1892, detailed the years before his professorship at UCL; in 1932 he published his second, more complete autobiography, 'Seventy Years in Archaeology'. After he died in 1942 there were various obituaries and memorials that outlined his life and major achievements in archaeology. There was very little written about Petrie the man until 1985, when Margaret Drower's 'Flinders Petrie: A Life in Archaeology' was published; it remains the most comprehensive work on Petrie's life. A thin volume of the correspondence of Hilda and Flinders Petrie also allows a glimpse into life on excavation. In short, much of what is known about Petrie focuses on his excavations in Egypt, his time as Professor of Egyptology at University College London, or the museum that bears his name. Subsequently, as a historical matter, Petrie's work in the discipline of eugenics has rarely been discussed as part of his career.

SHER: A Colored Petri Net Based Random Mobility Model for Wireless Communications

Science.gov (United States)

Khan, Naeem Akhtar; Ahmad, Farooq; Khan, Sher Afzal

2015-01-01

In wireless network research, simulation is the most imperative technique to investigate the network’s behavior and validation. Wireless networks typically consist of mobile hosts; therefore, the degree of validation is influenced by the underlying mobility model, and synthetic models are implemented in simulators because real life traces are not widely available. In wireless communications, mobility is an integral part while the key role of a mobility model is to mimic the real life traveling patterns to study. The performance of routing protocols and mobility management strategies e.g. paging, registration and handoff is highly dependent to the selected mobility model. In this paper, we devise and evaluate the Show Home and Exclusive Regions (SHER), a novel two-dimensional (2-D) Colored Petri net (CPN) based formal random mobility model, which exhibits sociological behavior of a user. The model captures hotspots where a user frequently visits and spends time. Our solution eliminates six key issues of the random mobility models, i.e., sudden stops, memoryless movements, border effect, temporal dependency of velocity, pause time dependency, and speed decay in a single model. The proposed model is able to predict the future location of a mobile user and ultimately improves the performance of wireless communication networks. The model follows a uniform nodal distribution and is a mini simulator, which exhibits interesting mobility patterns. The model is also helpful to those who are not familiar with the formal modeling, and users can extract meaningful information with a single mouse-click. It is noteworthy that capturing dynamic mobility patterns through CPN is the most challenging and virulent activity of the presented research. Statistical and reachability analysis techniques are presented to elucidate and validate the performance of our proposed mobility model. The state space methods allow us to algorithmically derive the system behavior and rectify the

Phased mission modelling of systems with maintenance-free operating periods using simulated Petri nets

Energy Technology Data Exchange (ETDEWEB)

Chew, S.P.; Dunnett, S.J. [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough, Leics (United Kingdom); Andrews, J.D. [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough, Leics (United Kingdom)], E-mail: j.d.andrews@lboro.ac.uk

2008-07-15

A common scenario in engineering is that of a system which operates throughout several sequential and distinct periods of time, during which the modes and consequences of failure differ from one another. This type of operation is known as a phased mission, and for the mission to be a success the system must successfully operate throughout all of the phases. Examples include a rocket launch and an aeroplane flight. Component or sub-system failures may occur at any time during the mission, yet not affect the system performance until the phase in which their condition is critical. This may mean that the transition from one phase to the next is a critical event that leads to phase and mission failure, with the root cause being a component failure in a previous phase. A series of phased missions with no maintenance may be considered as a maintenance-free operating period (MFOP). This paper describes the use of a Petri net (PN) to model the reliability of the MFOP and phased missions scenario. The model uses Monte-Carlo simulation to obtain its results, and due to the modelling power of PNs, can consider complexities such as component failure rate interdependencies and mission abandonment. The model operates three different types of PN which interact to provide the overall system reliability modelling. The model is demonstrated and validated by considering two simple examples that can be solved analytically.

Phased mission modelling of systems with maintenance-free operating periods using simulated Petri nets

International Nuclear Information System (INIS)

Chew, S.P.; Dunnett, S.J.; Andrews, J.D.

2008-01-01

A common scenario in engineering is that of a system which operates throughout several sequential and distinct periods of time, during which the modes and consequences of failure differ from one another. This type of operation is known as a phased mission, and for the mission to be a success the system must successfully operate throughout all of the phases. Examples include a rocket launch and an aeroplane flight. Component or sub-system failures may occur at any time during the mission, yet not affect the system performance until the phase in which their condition is critical. This may mean that the transition from one phase to the next is a critical event that leads to phase and mission failure, with the root cause being a component failure in a previous phase. A series of phased missions with no maintenance may be considered as a maintenance-free operating period (MFOP). This paper describes the use of a Petri net (PN) to model the reliability of the MFOP and phased missions scenario. The model uses Monte-Carlo simulation to obtain its results, and due to the modelling power of PNs, can consider complexities such as component failure rate interdependencies and mission abandonment. The model operates three different types of PN which interact to provide the overall system reliability modelling. The model is demonstrated and validated by considering two simple examples that can be solved analytically

Complexity metrics for workflow nets

NARCIS (Netherlands)

Lassen, K.B.; Aalst, van der W.M.P.

2009-01-01

Process modeling languages such as EPCs, BPMN, flow charts, UML activity diagrams, Petri nets, etc., are used to model business processes and to configure process-aware information systems. It is known that users have problems understanding these diagrams. In fact, even process engineers and system

Complexity Metrics for Workflow Nets

DEFF Research Database (Denmark)

Lassen, Kristian Bisgaard; van der Aalst, Wil M.P.

2009-01-01

Process modeling languages such as EPCs, BPMN, flow charts, UML activity diagrams, Petri nets, etc.\\ are used to model business processes and to configure process-aware information systems. It is known that users have problems understanding these diagrams. In fact, even process engineers and system...

ANALYSIS OF SUBJECT DISCRETE MATHEMATICS PARTS AND PROPOSAL OF E-COURSE MODEL FOLLOWING PETRI NETS FOR INFORMATICS EDUCATION

Directory of Open Access Journals (Sweden)

TURČÁNI, Milan

2013-03-01

Full Text Available Nowadays, quality Mathematical basis - Informatics is an inherent part of study. Mathematical basis is provided by Discrete Mathematics that is taught as a compulsory subject in stated study program in the Department of Mathematics. Authors clarify significance and importance of simple thematic units of subject Discrete Mathematics in teaching technical-system subjects in study programme Applied Informatics. Mentioned subject is being taught in first year of University study and knowledge that students acquire during the study of this course are the "cornerstone" for their further development in technical-system study. Justness and importance of individual topics were analysed based on the evaluation of questionnaires, in which pedagogues teaching professional IT subjects alloted weighted coefficients to individual thematic units. Weighted coefficients were alloted based on the significance of the given topic of the subject Discrete Math, with regard to the IT subject they are teaching. Upon designing the e-course, experience with the creation of linear and branch teaching software were used. For the simulation of the transition of students through individual lessons as well as the whole course, authors employed the method of the teaching process simulation using Petri nets.

SOFTWARE FOR FAULT DIAGNOSIS USING KNOWLEDGE MODELS IN PETRI NETS

Directory of Open Access Journals (Sweden)

ADRIAN ARBOLEDA

2012-01-01

Full Text Available Los sistemas de diagnóstico de fallas en empresas asociadas al sector eléctrico requieren propiedades de precisión y flexibilidad cuando surgen eventos de falla. Actualmente existen sistemas que pretenden mejorar el proceso de diagnóstico mediante varios métodos y técnicas computacionales, reduciendo el tiempo de respuesta a perturbaciones. Sin embargo, son pocas las propuestas que unifican modelos gráficos de conocimiento con las señales de un proceso que pueden ofrecer dispositivos como controladores lógicos programables (PLCs. Este artículo propone un software novedoso guiado por modelos basados en redes de Petri e integrado con señales del proceso, para el diagnóstico de falla en centrales de generación eléctrica. Un caso de estudio demuestra la flexibilidad y adaptabilidad del software cuando nuevas nociones en los modelos de conocimiento cambian, sin realizar procedimientos de reingeniería al software.

Sociophysics of sexism: normal and anomalous petrie multipliers

Science.gov (United States)

Eliazar, Iddo

2015-07-01

A recent mathematical model by Karen Petrie explains how sexism towards women can arise in organizations where male and female are equally sexist. Indeed, the Petrie model predicts that such sexism will emerge whenever there is a male majority, and quantifies this majority bias by the ‘Petrie multiplier’: the square of the male/female ratio. In this paper—emulating the shift from ‘normal’ to ‘anomalous’ diffusion—we generalize the Petrie model to a stochastic Poisson model that accommodates heterogeneously sexist men and woman, and that extends the ‘normal’ quadratic Petrie multiplier to ‘anomalous’ non-quadratic multipliers. The Petrie multipliers span a full spectrum of behaviors which we classify into four universal types. A variation of the stochastic Poisson model and its Petrie multipliers is further applied to the context of cyber warfare.

An Evaluation of Automated Code Generation with the PetriCode Approach

DEFF Research Database (Denmark)

Simonsen, Kent Inge

2014-01-01

Automated code generation is an important element of model driven development methodologies. We have previously proposed an approach for code generation based on Coloured Petri Net models annotated with textual pragmatics for the network protocol domain. In this paper, we present and evaluate thr...... important properties of our approach: platform independence, code integratability, and code readability. The evaluation shows that our approach can generate code for a wide range of platforms which is integratable and readable....

Séquentialisation du comportement des réseaux de Petri temporisés

Czech Academy of Sciences Publication Activity Database

Boimond, J.-L.; Komenda, Jan; Lahaye, S.

2013-01-01

Roč. 47, 1-3 (2013), s. 139-154 ISSN 1269-6935. [Modélisation des Systèmes Réactifs (MSR) 2013. Rennes, 13.11.2013-15.11.2013] R&D Projects: GA ČR(CZ) GAP103/11/0517 Institutional support: RVO:67985840 Keywords : timed Petri nets * (max,+) automata * race policy Subject RIV: BA - General Mathematics http://jesa.revuesonline.com/article.jsp?articleId=18769

Formal verfication of a railway crossing controller using time petri nets; Taimupetorinetto wo mochiita fumikiri seigyo puroguramu no keishikiteki kensho

Energy Technology Data Exchange (ETDEWEB)

Sasaki, R. [The Nippon Signal Co. Ltd., Tokyo (Japan); Yoneda, T. [Tokyo Inst. of Technology, Tokyo (Japan)

1994-12-20

In the system requesting the real-time property, detecting the dugs in the method by carrying out the verification at the stage of method is important for excluding the error from the latter process. The verifying device for investigating whether the properties are satisfied by the system with the expression of the operation rules of system with time Petri nets and presenting the properties to be verified with real-time linear time-phase theory is developed by Yoneda, et al. In this paper, the verification of train check and warning-controlling operation in railway-crossing is carried out by using said verifying device, and the effectiveness of this verifying method is examined. In the practical controlling program, the mistakes in design occurs easily because of the further execution of complex processings including the countermeasure to the defect of short circuit in controlling unit and the control of up/down trains. It is planned in the future to modeled such processings as well as functions and to verify the system more utilizable. 12 refs., 11 figs., 1 tab.

CPN Tools for Editing, Simulating, and Analysing Coloured Petri Nets

DEFF Research Database (Denmark)

Ratzer, Anne Vinter; Wells, Lisa Marie; Lassen, Henry Michael

2003-01-01

elements. The tool features incremental syntax checking and code generation which take place while a net is being constructed. A fast simulator efficiently handles both untimed and timed nets. Full and partial state spaces can be generated and analysed, and a standard state space report contains...

Modelagem e análise de serviços de saúde baseados em Redes de Petri interpretadas

Directory of Open Access Journals (Sweden)

Marisa Mitie Miyagi

2001-12-01

Full Text Available Este trabalho introduz as Redes de Petri para modelagem e análise de sistemas de saúde que além da complexidade de suas atividades, envolve na sua concepção, implementação, operação e tomada de decisões, vários e diferentes profissionais. Os modelos são desenvolvidos em PFS (Production Flow Schema e MFG (Mark Flow Graph que são interpretações de redes de Petri, explicitando os recursos envolvidos e o fluxo de itens (pessoas, equipamentos, informações. Os serviços do Ambulatório do Hospital das Clínicas da Universidade de São Paulo são utilizados como estudo de caso para comprovar as vantagens da presente proposta.This paper introduces the Petri net for modelling and analysis of health systems where beyond the complexity of they activities, involves in its conception, implementation, operation and decision making several and differents professionals. The models are developed in PFS (Production Flow Schema and MFC (Mark Flow Graph that are interpretations of Peri nets aiming the explicit identification of resources and flow of itens (material and information. The services of the ambulatory of Clinic Hospital of University of São Paulo is considered in a case study to confirm the advantages of the proposal.

TAPAAL and Reachability Analysis of P/T Nets

DEFF Research Database (Denmark)

Jensen, Jonas Finnemann; Nielsen, Thomas Søndersø; Østergaard, Lars Kærlund

2016-01-01

We discuss selected model checking techniques used in the tool TAPAAL for the reachability analysis of weighted Petri nets with inhibitor arcs. We focus on techniques that had the most significant effect at the 2015 Model Checking Contest (MCC). While the techniques are mostly well known, our...... contribution lies in their adaptation to the MCC reachability queries, their efficient implementation and the evaluation of their performance on a large variety of nets from MCC'15....

Time-dependent structural transformation analysis to high-level Petri net model with active state transition diagram

Directory of Open Access Journals (Sweden)

Saito Ayumu

2010-04-01

Full Text Available Abstract Background With an accumulation of in silico data obtained by simulating large-scale biological networks, a new interest of research is emerging for elucidating how living organism functions over time in cells. Investigating the dynamic features of current computational models promises a deeper understanding of complex cellular processes. This leads us to develop a method that utilizes structural properties of the model over all simulation time steps. Further, user-friendly overviews of dynamic behaviors can be considered to provide a great help in understanding the variations of system mechanisms. Results We propose a novel method for constructing and analyzing a so-called active state transition diagram (ASTD by using time-course simulation data of a high-level Petri net. Our method includes two new algorithms. The first algorithm extracts a series of subnets (called temporal subnets reflecting biological components contributing to the dynamics, while retaining positive mathematical qualities. The second one creates an ASTD composed of unique temporal subnets. ASTD provides users with concise information allowing them to grasp and trace how a key regulatory subnet and/or a network changes with time. The applicability of our method is demonstrated by the analysis of the underlying model for circadian rhythms in Drosophila. Conclusions Building ASTD is a useful means to convert a hybrid model dealing with discrete, continuous and more complicated events to finite time-dependent states. Based on ASTD, various analytical approaches can be applied to obtain new insights into not only systematic mechanisms but also dynamics.

Modeling user navigation behavior in web by colored Petri nets to determine the user's interest in recommending web pages

Directory of Open Access Journals (Sweden)

Mehdi Sadeghzadeh

2013-01-01

Full Text Available One of existing challenges in personalization of the web is increasing the efficiency of a web in meeting the users' requirements for the contents they require in an optimal state. All the information associated with the current user behavior following in web and data obtained from pervious users’ interaction in web can provide some necessary keys to recommend presentation of services, productions, and the required information of the users. This study aims at presenting a formal model based on colored Petri nets to identify the present user's interest, which is utilized to recommend the most appropriate pages ahead. In the proposed design, recommendation of the pages is considered with respect to information obtained from pervious users' profile as well as the current session of the present user. This model offers the updated proposed pages to the user by clicking on the web pages. Moreover, an example of web is modeled using CPN Tools. The results of the simulation show that this design improves the precision factor. We explain, through evaluation where the results of this method are more objective and the dynamic recommendations demonstrate that the results of the recommended method improve the precision criterion 15% more than the static method.

Validation, verification and evaluation of a Train to Train Distance Measurement System by means of Colored Petri Nets

International Nuclear Information System (INIS)

Song, Haifeng; Liu, Jieyu; Schnieder, Eckehard

2017-01-01

Validation, verification and evaluation are necessary processes to assure the safety and functionality of a system before its application in practice. This paper presents a Train to Train Distance Measurement System (TTDMS), which can provide distance information independently from existing onboard equipment. Afterwards, we proposed a new process using Colored Petri Nets to verify the TTDMS system functional safety, as well as to evaluate the system performance. Three main contributions are carried out in the paper: Firstly, this paper proposes a formalized TTDMS model, and the model correctness is validated using state space analysis and simulation-based verification. Secondly, corresponding checking queries are proposed for the purpose of functional safety verification. Further, the TTDMS performance is evaluated by applying parameters in the formal model. Thirdly, the reliability of a functional prototype TTDMS is estimated. It is found that the procedure can cooperate with the system development, and both formal and simulation-based verifications are performed. Using our process to evaluate and verify a system is easier to read and more reliable compared to executable code and mathematical methods. - Highlights: • A new Train to Train Distance Measurement System. • New approach verifying system functional safety and evaluating system performance by means of CPN. • System formalization using the system property concept. • Verification of system functional safety using state space analysis. • Evaluation of system performance applying simulation-based analysis.

Medição do inventário em processo e tempo de atravessamento em manufatura por modelagem em redes de Petri e diagrama de resultados Measurement of work-in-process and manufacturing leadtime by Petri nets modeling and throughput diagram

Directory of Open Access Journals (Sweden)

Tiago Facchin

2008-08-01

Full Text Available Este artigo apresenta um método para a medição de inventário em processo e tempo de atravessamento em um sistema de manufatura. O método consiste em modelar a manufatura por redes de Petri, simular o modelo em computador, alimentando-o com a situação de carga inicial dos processos e com um plano de produção, obtendo os momentos simulados de conclusão de cada ordem do plano. Após este procedimento, com o uso do diagrama de resultados e da fórmula do funil, calcula-se o valor médio simulado de inventário em processo que o plano produzirá na manufatura. Ao fim, faz-se uma discussão na qual explora-se como os resultados do método podem ser úteis em decisões de gestão, envolvendo o inventário admitido, pulmões e restrições da manufatura.This paper presents a method to measure work-in-process and leadtime in a manufacturing system. The method consists of modeling manufacturing by Petri nets, providing as input for the model the initial load of the process and a production plan, running it and obtaining from the simulation the moments of completion of the orders. Using the throughput diagram and the funnel formula, we then calculate the mean simulated value of the work-in-process that the plan will produce in the manufacturing system. Finally, we discuss how the results can be used to underpin management decisions on issues such as actual work-in-process, buffers and manufacturing constraints.

Contribution to the modelling and analysis of logistics system performance by Petri nets and simulation models: Application in a supply chain

Science.gov (United States)

Azougagh, Yassine; Benhida, Khalid; Elfezazi, Said

2016-02-01

In this paper, the focus is on studying the performance of complex systems in a supply chain context by developing a structured modelling approach based on the methodology ASDI (Analysis, Specification, Design and Implementation) by combining the modelling by Petri nets and simulation using ARENA. The linear approach typically followed in conducting of this kind of problems has to cope with a difficulty of modelling due to the complexity and the number of parameters of concern. Therefore, the approach used in this work is able to structure modelling a way to cover all aspects of the performance study. The modelling structured approach is first introduced before being applied to the case of an industrial system in the field of phosphate. Results of the performance indicators obtained from the models developed, permitted to test the behaviour and fluctuations of this system and to develop improved models of the current situation. In addition, in this paper, it was shown how Arena software can be adopted to simulate complex systems effectively. The method in this research can be applied to investigate various improvements scenarios and their consequences before implementing them in reality.

Petri neural network model for the effect of controlled thermomechanical process parameters on the mechanical properties of HSLA steels

Energy Technology Data Exchange (ETDEWEB)

Datta, S.

1999-10-01

The effect of composition and controlled thermomechanical process parameters on the mechanical properties of HSLA steels is modelled using the Widrow-Hoff's concept of training a neural net with feed-forward topology by applying Rumelhart's back propagation type algorithm for supervised learning, using a Petri like net structure. The data used are from laboratory experiments as well as from the published literature. The results from the neural network are found to be consistent and in good agreement with the experimented results. (author)

WorkflowNet2BPEL4WS: A Tool for Translating Unstructured Workflow Processes to Readable BPEL

DEFF Research Database (Denmark)

Lassen, Kristian Bisgaard; van der Aalst, Wil M. P.

2007-01-01

code and not easy to use by end-users. Therefore, we provide a mapping from WF-nets to BPEL. This mapping builds on the rich theory of Petri nets and can also be used to map other languages (e.g., UML, EPC, BPMN, etc.) onto BPEL. To evaluate WorkflowNet2BPEL4WS we used more than 100 processes modeled...

Automatic generation of control solution for resource allocation using Petri net model Geração automática da solução de controle para alocação de recursos utilizando redes de Petri

Directory of Open Access Journals (Sweden)

Francisco Yastami Nakamoto

2009-04-01

Full Text Available The flexible manufacturing system (FMS executes multiple processes simultaneously using a limited set of resources. These processes can be blocked permanently due to the sequence of the activities, i.e., the processes sharing a finite set of resources may eventually lead to a deadlock state. The FMS belongs to the class of discrete event systems where it is not possible to determine when an event will occur and the sequence of events becomes undefined. Such systems can be modeled using Petri net, and this work presents a method that solves the deadlock problem considering the indeterminism of FMSs. The goal of this work is to introduce an algorithmic approach, which allows the implementation of a computer program based on FMS functional specification. The proposal is to automate the generation of the control strategy for resource utilization and the rules to avoid the deadlock situation.O sistema flexível de manufatura (FMS flexible manufacturing system executa múltiplos processos simultaneamente que utilizam um conjunto limitado de recursos. Estes processos podem ficar permanentemente bloqueados em função da seqüência de atividades, isto é, o compartilhamento de um conjunto finito de recursos pode levar o sistema a um estado de autotravamento. O FMS pode ser visto como pertencente a uma classe de sistema a eventos discretos, onde não é possível determinar quando um evento ocorre e com isto a seqüência de eventos fica indefinida. Este tipo de sistema pode ser modelado através de rede de Petri e assim explora-se esta técnica para desenvolver uma solução para o problema de auto-travamento considerando o indeterminismo do FMS. O objetivo é introduzir uma abordagem algorítmica para a implementação de uma ferramenta computacional baseada na especificação funcional do FMS e que automatize a geração de uma estratégia de controle para a utilização de recursos e de regras para evitar o autotravamento.

A net presentation of Lithuanian sentences containing verbal forms with the grammatical suffix -dav-

Directory of Open Access Journals (Sweden)

Danuta Roszko

2014-09-01

Full Text Available A net presentation of Lithuanian sentences containing verbal forms with the grammatical suffix -dav- In the article the authors make an attempt to present the meaning of Lithuanian sentences containing verbal forms with the grammatical suffix -dav- (the so-called iterative past tense forms by means of Petri nets. The authors gradually develop the net to such complexity that it makes it possible to avoid interpretative similarities to other Lithuanian verbal forms.

OR.NET: a service-oriented architecture for safe and dynamic medical device interoperability.

Science.gov (United States)

Kasparick, Martin; Schmitz, Malte; Andersen, Björn; Rockstroh, Max; Franke, Stefan; Schlichting, Stefan; Golatowski, Frank; Timmermann, Dirk

2018-02-23

Modern surgical departments are characterized by a high degree of automation supporting complex procedures. It recently became apparent that integrated operating rooms can improve the quality of care, simplify clinical workflows, and mitigate equipment-related incidents and human errors. Particularly using computer assistance based on data from integrated surgical devices is a promising opportunity. However, the lack of manufacturer-independent interoperability often prevents the deployment of collaborative assistive systems. The German flagship project OR.NET has therefore developed, implemented, validated, and standardized concepts for open medical device interoperability. This paper describes the universal OR.NET interoperability concept enabling a safe and dynamic manufacturer-independent interconnection of point-of-care (PoC) medical devices in the operating room and the whole clinic. It is based on a protocol specifically addressing the requirements of device-to-device communication, yet also provides solutions for connecting the clinical information technology (IT) infrastructure. We present the concept of a service-oriented medical device architecture (SOMDA) as well as an introduction to the technical specification implementing the SOMDA paradigm, currently being standardized within the IEEE 11073 service-oriented device connectivity (SDC) series. In addition, the Session concept is introduced as a key enabler for safe device interconnection in highly dynamic ensembles of networked medical devices; and finally, some security aspects of a SOMDA are discussed.

Soundness of Timed-Arc Workflow Nets in Discrete and Continuous-Time Semantics

DEFF Research Database (Denmark)

Mateo, Jose Antonio; Srba, Jiri; Sørensen, Mathias Grund

2015-01-01

Analysis of workflow processes with quantitative aspectslike timing is of interest in numerous time-critical applications. We suggest a workflow model based on timed-arc Petri nets and studythe foundational problems of soundness and strong (time-bounded) soundness.We first consider the discrete-t...

A framework for the definition of variants of high-level Petri nets

DEFF Research Database (Denmark)

Kindler, Ekkart; Petrucci, Laure

2009-01-01

with data-type specific issues, which often blocks the view for the really relevant parts. Even worse, supposedly simpler versions of high-level nets often are more difficult to define than high-level nets in general. This paper introduces the concepts and the mathematical tools to ease the definition...

Reliability-Based and Cost-Oriented Product Optimization Integrating Fuzzy Reasoning Petri Nets, Interval Expert Evaluation and Cultural-Based DMOPSO Using Crowding Distance Sorting

Directory of Open Access Journals (Sweden)

Zhaoxi Hong

2017-08-01

Full Text Available In reliability-based and cost-oriented product optimization, the target product reliability is apportioned to subsystems or components to achieve the maximum reliability and minimum cost. Main challenges to conducting such optimization design lie in how to simultaneously consider subsystem division, uncertain evaluation provided by experts for essential factors, and dynamic propagation of product failure. To overcome these problems, a reliability-based and cost-oriented product optimization method integrating fuzzy reasoning Petri net (FRPN, interval expert evaluation and cultural-based dynamic multi-objective particle swarm optimization (DMOPSO using crowding distance sorting is proposed in this paper. Subsystem division is performed based on failure decoupling, and then subsystem weights are calculated with FRPN reflecting dynamic and uncertain failure propagation, as well as interval expert evaluation considering six essential factors. A mathematical model of reliability-based and cost-oriented product optimization is established, and the cultural-based DMOPSO with crowding distance sorting is utilized to obtain the optimized design scheme. The efficiency and effectiveness of the proposed method are demonstrated by the numerical example of the optimization design for a computer numerically controlled (CNC machine tool.

Petri Net-Based Model of Helicobacter pylori Mediated Disruption of Tight Junction Proteins in Stomach Lining during Gastric Carcinoma

Directory of Open Access Journals (Sweden)

Anam Naz

2017-09-01

Full Text Available Tight junctions help prevent the passage of digestive enzymes and microorganisms through the space between adjacent epithelial cells lining. However, Helicobacter pylori encoded virulence factors negatively regulate these tight junctions and contribute to dysfunction of gastric mucosa. Here, we have predicted the regulation of important tight junction proteins, such as Zonula occludens-1, Claudin-2 and Connexin32 in the presence of pathogenic proteins. Molecular events such as post translational modifications and crosstalk between phosphorylation, O-glycosylation, palmitoylation and methylation are explored which may compromise the integrity of these tight junction proteins. Furthermore, the signaling pathways disrupted by dysregulated kinases, proteins and post-translational modifications are reviewed to design an abstracted computational model showing the situation-dependent dynamic behaviors of these biological processes and entities. A qualitative hybrid Petri Net model is therefore constructed showing the altered host pathways in the presence of virulence factor cytotoxin-associated gene A, leading to the disruption of tight junction proteins. The model is qualitative logic-based, which does not depend on any kinetic parameter and quantitative data and depends on knowledge derived from experiments. The designed model provides insights into the tight junction disruption and disease progression. Model is then verified by the available experimental data, nevertheless formal in vitro experimentation is a promising way to ensure its validation. The major findings propose that H. pylori activated kinases are responsible to trigger specific post translational modifications within tight junction proteins, at specific sites. These modifications may favor alterations in gastric barrier and provide a route to bacterial invasion into host cells.

An Introduction to the Theoretical Aspects of Coloured Petri nets

DEFF Research Database (Denmark)

Jensen, Kurt

1994-01-01

other systems in which human beings and/or computers communicate by means of some more or less formal rules). The paper contains the formal definition of CP-nets and their basic concepts (e.g., the different dynamic properties such as liveness and fairness). The paper also contains a short introduction...

Simulation of machine-maintenance training in virtual environment

International Nuclear Information System (INIS)

Yoshikawa, Hidekazu; Tezuka, Tetsuo; Kashiwa, Ken-ichiro; Ishii, Hirotake

1997-01-01

The periodical inspection of nuclear power plants needs a lot of workforces with a high degree of technical skill for the maintenance of various sorts of machines. Therefore, a new type of maintenance training system is required, where trainees can get training safely, easily and effectively. In this study we developed a training simulation system for disassembling a check valve in virtual environment (VE). The features of this system are as follows: Firstly, the trainees can execute tasks even in wrong order, and can experience the resultant conditions. In order to realize this environment, we developed a new Petri-net model for representing the objects' states in VE. This Petri-net model has several original characteristics, which make it easier to manage the change of the objects' states. Furthermore, we made a support system for constructing the Petri-net model of machine-disassembling training, because the Petri-net model is apt to become of large size. The effectiveness of this support system is shown through the system development. Secondly, this system can perform appropriate tasks to be done next in VE whenever the trainee wants even after some mistakes have been made. The effectiveness of this function has also been confirmed by experiments. (author)

Complexity Metrics for Workflow Nets

DEFF Research Database (Denmark)

Lassen, Kristian Bisgaard; van der Aalst, Wil M.P.

2009-01-01

analysts have difficulties grasping the dynamics implied by a process model. Recent empirical studies show that people make numerous errors when modeling complex business processes, e.g., about 20 percent of the EPCs in the SAP reference model have design flaws resulting in potential deadlocks, livelocks......, etc. It seems obvious that the complexity of the model contributes to design errors and a lack of understanding. It is not easy to measure complexity, however. This paper presents three complexity metrics that have been implemented in the process analysis tool ProM. The metrics are defined...... for a subclass of Petri nets named Workflow nets, but the results can easily be applied to other languages. To demonstrate the applicability of these metrics, we have applied our approach and tool to 262 relatively complex Protos models made in the context of various student projects. This allows us to validate...

Perti Net-Based Workflow Access Control Model

Institute of Scientific and Technical Information of China (English)

陈卓; 骆婷; 石磊; 洪帆

2004-01-01

Access control is an important protection mechanism for information systems. This paper shows how to make access control in workflow system. We give a workflow access control model (WACM) based on several current access control models. The model supports roles assignment and dynamic authorization. The paper defines the workflow using Petri net. It firstly gives the definition and description of the workflow, and then analyzes the architecture of the workflow access control model (WACM). Finally, an example of an e-commerce workflow access control model is discussed in detail.

Synthesis of Decentralized Supervisor for Petri Nets Using Decomposition with Overlapping Places

Czech Academy of Sciences Publication Activity Database

Papík, Martin; Moravec, J.

2012-01-01

Roč. 6, č. 124 (2012), s. 6181-6194 ISSN 1312-885X Institutional support: RVO:67985556 Keywords : Perti nets * loopback control * decentralization Subject RIV: IN - Informatics, Computer Science http://library.utia.cas.cz/separaty/2012/ZOI/papik-0382079.pdf

Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt; Kristensen, Lars Michael

studies that illustrate the practical use of CPN modelling and validation for design, specification, simulation, verification and implementation in various application domains. Their presentation primarily aims at readers interested in the practical use of CPN. Thus all concepts and constructs are first...... informally introduced through examples and then followed by formal definitions (which may be skipped). The book is ideally suitable for a one-semester course at an advanced undergraduate or graduate level, and through its strong application examples can also serve for self-study. It features an accompanying...

Odvrácená tvář otce egyptské archeologie William Matthew Flinders Petrie a eugenická věda // The Dark Side of the Father of Egyptian Archaeology William Matthew Flinders Petrie and Eugenic Science

Directory of Open Access Journals (Sweden)

Kamila Tomášková

2016-06-01

Full Text Available The text aims to bring attention of the Czech readers to Petrie's contributions to the eugenics movement in Great Britain. It describes his close association with Francis Galton and his resulting pronounced views on eugenics and shows how Petrie's racist opinions and involvement in eugenics influenced hi s work as an archaeologist and historian. An attempt is made to understand Petrie's views in the context ofhis times instead of condemning him for hi s appalling conclusions motivated by his racism and eugenics beliefs. The text offers a perspective which enables the readers to consider Petrie's thoughts in relation to the eugenic movement which was not on ly favoured by many ofhis contemporaries, but also had many supporters Jong after Petrie's death. Any consideration of the influence of past ideologies and context on Petrie's thinking and research also brings forward an unanswerable question ofhow much each one of u s is influenced by the ideologies and the context(s prevalent in present times and culture.

Community pharmacist participation in a practice-based research network: a report from the Medication Safety Research Network of Indiana (Rx-SafeNet).

Science.gov (United States)

Patel, Puja; Hemmeger, Heather; Kozak, Mary Ann; Gernant, Stephanie A; Snyder, Margie E

2015-01-01

To describe the experiences and opinions of pharmacists serving as site coordinators for the Medication Safety Research Network of Indiana (Rx-SafeNet). Retail chain, independent, and hospital/health system outpatient community pharmacies throughout Indiana, with a total of 127 pharmacy members represented by 26 site coordinators. Rx-SafeNet, a statewide practice-based research network (PBRN) formed in 2010 and administered by the Purdue University College of Pharmacy. Barriers and facilitators to participation in available research studies, confidence participating in research, and satisfaction with overall network communication. 22 of 26 site coordinators participated, resulting in an 85% response rate. Most (72.2%) of the respondents had received a doctor of pharmacy degree, and 13.6% had postgraduate year (PGY)1 residency training. The highest reported benefits of PBRN membership were an enhanced relationship with the Purdue University College of Pharmacy (81% agreed or strongly agreed) and enhanced professional development (80% agreed or strongly agreed). Time constraints were identified as the greatest potential barrier to network participation, reported by 62% of respondents. In addition, the majority (59%) of survey respondents identified no prior research experience. Last, respondents' confidence in performing research appeared to increase substantially after becoming network members, with 43% reporting a lack of confidence in engaging in research before joining the network compared with 90% reporting confidence after joining the network. In general, Rx-SafeNet site coordinators appeared to experience increased confidence in research engagement after joining the network. While respondents identified a number of benefits associated with network participation, concerns about potential time constraints remained a key barrier to participation. These findings will assist network leadership in identifying opportunities to positively increase member participation

Modeling the Metabolism of Arabidopsis thaliana: Application of Network Decomposition and Network Reduction in the Context of Petri Nets

Directory of Open Access Journals (Sweden)

Ina Koch

2017-06-01

Full Text Available Motivation:Arabidopsis thaliana is a well-established model system for the analysis of the basic physiological and metabolic pathways of plants. Nevertheless, the system is not yet fully understood, although many mechanisms are described, and information for many processes exists. However, the combination and interpretation of the large amount of biological data remain a big challenge, not only because data sets for metabolic paths are still incomplete. Moreover, they are often inconsistent, because they are coming from different experiments of various scales, regarding, for example, accuracy and/or significance. Here, theoretical modeling is powerful to formulate hypotheses for pathways and the dynamics of the metabolism, even if the biological data are incomplete. To develop reliable mathematical models they have to be proven for consistency. This is still a challenging task because many verification techniques fail already for middle-sized models. Consequently, new methods, like decomposition methods or reduction approaches, are developed to circumvent this problem.Methods: We present a new semi-quantitative mathematical model of the metabolism of Arabidopsis thaliana. We used the Petri net formalism to express the complex reaction system in a mathematically unique manner. To verify the model for correctness and consistency we applied concepts of network decomposition and network reduction such as transition invariants, common transition pairs, and invariant transition pairs.Results: We formulated the core metabolism of Arabidopsis thaliana based on recent knowledge from literature, including the Calvin cycle, glycolysis and citric acid cycle, glyoxylate cycle, urea cycle, sucrose synthesis, and the starch metabolism. By applying network decomposition and reduction techniques at steady-state conditions, we suggest a straightforward mathematical modeling process. We demonstrate that potential steady-state pathways exist, which provide the

The education on landslides through the "BE-SAFE-NET" web-portal on Disaster Awareness.

Science.gov (United States)

Maquaire, O.; Castaldini, D.; Malet, J.-P.; von Elverfeldt, K.; Pla, F.; Soldati, M.; Greco, R.; Pasuto, A.

2009-04-01

The website on Disaster Awareness with the use of the internet "BE-SAFE-NET" is developed within the framework of the FORM-OSE programme (European Training Programme for South, East and West) of the EUR-OPA Major Hazards Agreement, hosted by the European Centre for Disaster Awareness with the use of the internet (BE-SAFE-NET, Nicosia, Cyprus). The website is dedicated for school actors (school-level children, teachers, administrative and technical staff, families and local authorities) in order to: - Inform on regulations, on tools for raising awareness for natural and man-made risks and on preventative measures; - Train children, teachers, administrative and technical staff and local authorities; - Produce interactive figures, photographs, videos and games; - Interact with newsgroups and electronic conferences. Together with the EUR-OPA Centre of Nicosia, the project associates several centres of the Major Hazards Agreement network: the European University for the Cultural Heritage (CUEBC) of Ravello (Italy) the European Centre for Risk Prevention (ECRP) of Sofia (Bulgaria), and the European Centre on Geomorphological Hazards (CERG) of Strasbourg (France). "BE-SAFE-NET" is defined as a network among European countries in order to provide e-learning material on natural hazards and risks primarily for schools (secondary school teachers), but also for the public in general. On the webpage, teachers, pupils and the interested public should find information on disaster prevention, preparation, immediate reaction and rehabilitation. The aim of the paper is to present the structure and the organisation of the web-portal following the pilot project focused on landslides and managed by CERG. Some examples of landslides pedagogical material are also presented. The website is structured in five main sections: 1. About the initiative; 2. Definition of common concepts (e.g. hazard (natural and man made), vulnerability, risk, disaster); 3. Pedagogical material (e.g. case

Numerical and experimental dosimetry of petri dish exposure setups

Energy Technology Data Exchange (ETDEWEB)

Burkhardt, M.; Pokovic, K.; Gnos, M.; Schmid, T.; Kuster, N. [Swiss Federal Inst. of Tech., Zurich (Switzerland)

1996-12-31

Crawford TEM cells are often used to exposure cell cultures or small animals in order to study the effects caused by high-frequency fields. They are self-contained, easy-to-use setups that provide a rather homogeneous field distribution in a large area around its center, corresponding approximately to far-field conditions. However, a number of conditions must be met if such TEM cells are intended to be used for in vitro experiments. For instance, poor interaction with the incident field must be maintained to avoid significant field disturbances in the TEM cell. This is best achieved with E-polarization, i.e., when the E-field vector is normal to the investigated cell layer lining the bottom of a synthetic Petri dish. In addition, E-polarization provides the most homogeneous field distribution of all polarizations within the entire layer of cells. In this paper, the authors present a detailed dosimetric assessment for 60 and 100 mm Petri dishes as well as for a 48-well titer plate at 835 MHz. The dosimetry was performed by using numerical computations. The modeling and the simplifications are validated by a second numerical technique and by experimental measurements. For thin liquid layers, an approximation formula is provided with which the induced field strength for many other experiments conducted in Petri dishes can be assessed reliably.

Modular PNML revisited: Some ideas for strict typing

DEFF Research Database (Denmark)

Kindler, Ekkart

2007-01-01

The Petri Net Markup Language (PNML) is currently standardised by ISO/IEC JTC1/SC7 WG 19 as Part 2 of ISO/IEC 15909. But, there is not yet a mechanism for structuring large Petri nets and for constructing Petri nets from modules. To this end, modular PNML has been proposed some time ago. But, mod...... of Petri net, but still has a strict type system. This paper focuses on the ideas and concepts; the technical details still need to be worked out. To this end, this paper also raises some issues and questions that need to be discussed before standardising modular PNML....

An Advanced Environment for Hybrid Modeling of Biological Systems Based on Modelica

Directory of Open Access Journals (Sweden)

Proß Sabrina

2011-03-01

Full Text Available Biological systems are often very complex so that an appropriate formalism is needed for modeling their behavior. Hybrid Petri Nets, consisting of time-discrete Petri Net elements as well as continuous ones, have proven to be ideal for this task. Therefore, a new Petri Net library was implemented based on the object-oriented modeling language Modelica which allows the modeling of discrete, stochastic and continuous Petri Net elements by differential, algebraic and discrete equations. An appropriate Modelica-tool performs the hybrid simulation with discrete events and the solution of continuous differential equations. A special sub-library contains so-called wrappers for specific reactions to simplify the modeling process.

一种基于TC-CPN的城轨列车车门故障溯因诊断方法%An Abductive Diagnosis Method for Urban Rail Train Door Faults Based on Cyber Petri Net of Time Constraint

Institute of Scientific and Technical Information of China (English)

沈碧波; 佘维; 叶阳东; 贾利民

2016-01-01

本文针对城轨列车车门开门控制系统故障诊断问题,定义一种时间约束自控Petri网(TC-CPN),提出一种故障溯因诊断方法.该方法主要依据捕获的故障表征和监控系统采集的状态与时间信息进行诊断分析.该Petri网引入时序一致性判定函数,定义相对应的变迁触发规则.通过对捕获的时间信息进行计算和溯因推理,分析系统可能存在的故障源或隐患.应用算例表明,时间约束自控Petri网对城轨列车车门开门控制系统的建模有效,时间约束为系统故障溯因诊断提供了时间层面的有力证据.该方法对于此类控制系统故障诊断问题具有一定的普适性.%Aiming at the fault diagnosis of on-off control system of urban rail train doors ,an abductive fault di-agnosis method was proposed by defining a novel type of Cyber Petri Net of Time Constraint (TC-CPN) .Diag-nostic analysis was carried out with the proposed method ,based on the captured fault characterization and the status and time information collected by the monitoring system .The Petri net adopted the judgment function of temporal consistency and defined the corresponding transition firing rules .By calculation and abductive reason-ing of the captured time information ,the fault origins or the potential problems that may remain in the control system were analyzed .The sample application showed that the TC-CPN was effective to model the on-off con-trol system of the doors of urban rail trains ,while time constraint provided strong evidence for fault abductive diagnosis in terms of time .The proposed method suggested general applicability to such fault diagnosis prob-lems of control systems .

Coloured Petri Nets: Basic Concepts, Analysis Methods and Practical Use. Vol. 3, Practical Use

DEFF Research Database (Denmark)

Jensen, Kurt

of this book. Redundancies with the material of the other volumes have been removed, e.g., the explanation of what a hierarchical CP-net is and how the CPN tools work. The typography has been modified to match that used for the other parts of the book. More detailed explanations have been added, e.g., of some...

Modelado de redes de Petri con retroalimentación de activación

OpenAIRE

López Eslava, Eduardo

2016-01-01

Muchos sistemas no pueden ser descritos por ecuaciones diferenciales, sistemas en los cuales la ocurrencia de algún evento puede llevar al sistema de un estado a otro, y en los cuales un evento puede ocurrir abruptamente o en un instante de tiempo indeterminado. Las redes de Petri son una herramienta matemática y gráfica para sistemas que presentan este tipo de características. El carácter visual de las redes de Petri nos permite observar el flujo de comportamiento de un sistema en cada una d...

CPN/Tools: A Post-WIMP Interface for Editing and Simulating Coloured Petri Nets

DEFF Research Database (Denmark)

Andersen, Peter; Beaudouin-Lafon, Michel; Mackay, Wendy E.

2001-01-01

traditional ideas about user interfaces, getting rid of pull-down menus, scrollbars, and even selection, while providing the same or greater functionality. It also uses the new and much faster CPN simulator and features incremental syntax checking of the nets. CPN/Tools requires an OpenGL graphics accelerator......CPN/Tools is a major redesign of the popular Design/CPN tool from the University of Aarhus CPN group. The new interface is based on advanced, post-WIMP interaction techniques, including bi-manual interaction, toolglasses and marking menus and a new metaphor for managing the workspace. It challenges...

Propuesta de un tipo de redes de Petri temporizadas para el modelado de procesos

OpenAIRE

Gonzaléz, Ariel; Vaisman, Gabriel David

2001-01-01

Las Redes de Petri (RP) son un formalismo gráfico para la especificación de sistemas, las cuales pertenecen a la clase de modelos operacionales y son apropiadas cuando se desean describir las propiedades dinámicas de los sistemas. Además, la flexibilidad del modelo permite extenderlo en varias direcciones manteniendo su filosofía original. En el presente trabajo utilizaremos como base un modelo de Red de Petri Temporizada basadas en relojes para luego extenderlo con el concepto de Subredes au...

Grigori Petrišin: Ajalehes Kesknädal 25. märtsil 2009 ilmunud publikatsiooni ümberlükkamine / Grigori Petrišin

Index Scriptorium Estoniae

Petrišin, Grigori

2009-01-01

Riigikogu liikme, endise Tallinna abilinnapea Kalev Kallo poole pöördus ettevõtja Grigori Petrišin, keda kaitsepolitsei oli sundinud väidetavalt oma firma nimel kirjutama linnajuhte kompromiteerivaid kirju. Nüüd väidab ettevõtja, et teda on ära kasutatud valimiseelsetes võimumängudes

Redes de Petri: Modelado e implementación de algoritmos para autómatas programables

Directory of Open Access Journals (Sweden)

Luis Diego Murillo

2008-04-01

Full Text Available El presente trabajo es una monografía orientada hacia la utilización del formalismo de las Redes de Petri, propuesto por Carl Petri en la descripción de Sistemas Dinámicos de Eventos Discretos (DEDS. Las Redes de Petri, cuyo acrónimo en inglés es PN, fueron utilizadas inicialmente para el análisis de algoritmos en la computación paralela o concurrente, pero dada la complejidad de los procesos productivos actuales, las PN son un método alternativo de diseño tanto para el procesoindustrial como para el controlador. En este sentido, este estudio hace una revisión de las referencias bibliográficas donde se indica cómo realizar el modelado y la implementación de algoritmos de control en Controladores Lógicos Programables (PLCs por sus siglas en inglés.

Simulation-based model checking approach to cell fate specification during Caenorhabditis elegans vulval development by hybrid functional Petri net with extension

Directory of Open Access Journals (Sweden)

Ueno Kazuko

2009-04-01

Full Text Available Abstract Background Model checking approaches were applied to biological pathway validations around 2003. Recently, Fisher et al. have proved the importance of model checking approach by inferring new regulation of signaling crosstalk in C. elegans and confirming the regulation with biological experiments. They took a discrete and state-based approach to explore all possible states of the system underlying vulval precursor cell (VPC fate specification for desired properties. However, since both discrete and continuous features appear to be an indispensable part of biological processes, it is more appropriate to use quantitative models to capture the dynamics of biological systems. Our key motivation of this paper is to establish a quantitative methodology to model and analyze in silico models incorporating the use of model checking approach. Results A novel method of modeling and simulating biological systems with the use of model checking approach is proposed based on hybrid functional Petri net with extension (HFPNe as the framework dealing with both discrete and continuous events. Firstly, we construct a quantitative VPC fate model with 1761 components by using HFPNe. Secondly, we employ two major biological fate determination rules – Rule I and Rule II – to VPC fate model. We then conduct 10,000 simulations for each of 48 sets of different genotypes, investigate variations of cell fate patterns under each genotype, and validate the two rules by comparing three simulation targets consisting of fate patterns obtained from in silico and in vivo experiments. In particular, an evaluation was successfully done by using our VPC fate model to investigate one target derived from biological experiments involving hybrid lineage observations. However, the understandings of hybrid lineages are hard to make on a discrete model because the hybrid lineage occurs when the system comes close to certain thresholds as discussed by Sternberg and Horvitz in

Augmented marked graphs

CERN Document Server

Cheung, King Sing

2014-01-01

Petri nets are a formal and theoretically rich model for the modelling and analysis of systems. A subclass of Petri nets, augmented marked graphs possess a structure that is especially desirable for the modelling and analysis of systems with concurrent processes and shared resources.This monograph consists of three parts: Part I provides the conceptual background for readers who have no prior knowledge on Petri nets; Part II elaborates the theory of augmented marked graphs; finally, Part III discusses the application to system integration. The book is suitable as a first self-contained volume

An object-oriented description method of EPMM process

Science.gov (United States)

Jiang, Zuo; Yang, Fan

2017-06-01

In order to use the object-oriented mature tools and language in software process model, make the software process model more accord with the industrial standard, it’s necessary to study the object-oriented modelling of software process. Based on the formal process definition in EPMM, considering the characteristics that Petri net is mainly formal modelling tool and combining the Petri net modelling with the object-oriented modelling idea, this paper provides this implementation method to convert EPMM based on Petri net into object models based on object-oriented description.

Cooperative Control of Multiple Unmanned Autonomous Vehicles

National Research Council Canada - National Science Library

Nygard, Kendall E

2005-01-01

.... This paper presents a Petri net approach to UA V decision making based on fuzzy reasoning. It shows that Petri nets are a viable tool for modeling and validating propositional logic for rule-based reasoning in UA V decisions...

Hierarchies in Coloured Petri Nets

DEFF Research Database (Denmark)

Huber, Peter; Jensen, Kurt; Shapiro, Robert M.

1991-01-01

constructs, and it illustrates them by means of two examples. The hierarchy constructs can be used for theoretical considerations, but their main use is to describe and analyse large real-world systems. All of the hierarchy constructs are supported by the editing and analysis facilities in the CPN Palette...

Scrum ja .Net ohjelmistokehityksessä

OpenAIRE

Marttinen, Petri

2009-01-01

  Marttinen, Petri Juhani Tietojärjestelmätieteen kandidaatintutkielma / Petri Marttinen Jyväskylä: Jyväskylän yliopisto, 2009. 21 s. Kandidaatintutkielma Ohjelmistokehitys on monimutkainen liiketoiminta-alue. Nykyään ohjelmistot mallintavat aina vain tarkemmin todellista ympäristöämme, joten monimutkaisuus ei ole enää yllätys kenellekään. Scrum menetelmä on kehitetty tuottamaan käytettävyydeltään ja laadultaan hyviä ohjelmistoja monim...

Analysis hierarchical model for discrete event systems

Science.gov (United States)

Ciortea, E. M.

2015-11-01

The This paper presents the hierarchical model based on discrete event network for robotic systems. Based on the hierarchical approach, Petri network is analysed as a network of the highest conceptual level and the lowest level of local control. For modelling and control of complex robotic systems using extended Petri nets. Such a system is structured, controlled and analysed in this paper by using Visual Object Net ++ package that is relatively simple and easy to use, and the results are shown as representations easy to interpret. The hierarchical structure of the robotic system is implemented on computers analysed using specialized programs. Implementation of hierarchical model discrete event systems, as a real-time operating system on a computer network connected via a serial bus is possible, where each computer is dedicated to local and Petri model of a subsystem global robotic system. Since Petri models are simplified to apply general computers, analysis, modelling, complex manufacturing systems control can be achieved using Petri nets. Discrete event systems is a pragmatic tool for modelling industrial systems. For system modelling using Petri nets because we have our system where discrete event. To highlight the auxiliary time Petri model using transport stream divided into hierarchical levels and sections are analysed successively. Proposed robotic system simulation using timed Petri, offers the opportunity to view the robotic time. Application of goods or robotic and transmission times obtained by measuring spot is obtained graphics showing the average time for transport activity, using the parameters sets of finished products. individually.

The BRITNeY Suite: A Platfor for Experiments

DEFF Research Database (Denmark)

Westergaard, Michael

2006-01-01

This paper describes a platform, the BRITNeY Suite, for experimenting with Coloured Petri nets. The BRITNeY Suite provides access to data-structures and a simulator for Coloured Petri nets via a powerful scripting language and plug-in-mechanism, thereby making it easy to perform customized...

Avaliação do desempenho logístico do transporte rodoviário de madeira de áreas de fomento florestal com o uso de rede de Petri Evaluation of the wood hauling logistic performance in farm forest areas using Petri net

Directory of Open Access Journals (Sweden)

Carlos Cardoso Machado

2009-12-01

of optimizing physical resources, guaranteeing a flow of uninterrupted provisioning and appropriate volume of wood entrance in the regional deposits. The operational cycle of wood transport is organized by the activities of wood loading in the field, wood hauling, wood unloading in the deposit and unhauling. The Temporal Petri Net was used, because it works with two times - sensitization duration. Simulations were carried out with the ARP and ARP software systems, in order to simulate, analyze and evaluate the operational performance. The variations employed in each scenery are due to the quality of the highway, under the current conditions, as for the vertical and horizontal geometry and the irregularity quotient, in each deposit, for the different types of vehicle and form of the adopted wood loading. In the areas of uneven topography, the improvement of the highways altering their quality level has a higher influence for the increase in the performance of the vehicles, and Toco and Truck presented better results. In the areas of plains, the choice of the vehicle has a higher influence in the increase of the performance of the transport, since the topography and the quality of the current highways already contribute to the performance. In these cases, the relation between transported ton and distance and time will be higher for the vehicles with higher capacity of liquid load.

Modelling and analysis of workflow for lean supply chains

Science.gov (United States)

Ma, Jinping; Wang, Kanliang; Xu, Lida

2011-11-01

Cross-organisational workflow systems are a component of enterprise information systems which support collaborative business process among organisations in supply chain. Currently, the majority of workflow systems is developed in perspectives of information modelling without considering actual requirements of supply chain management. In this article, we focus on the modelling and analysis of the cross-organisational workflow systems in the context of lean supply chain (LSC) using Petri nets. First, the article describes the assumed conditions of cross-organisation workflow net according to the idea of LSC and then discusses the standardisation of collaborating business process between organisations in the context of LSC. Second, the concept of labelled time Petri nets (LTPNs) is defined through combining labelled Petri nets with time Petri nets, and the concept of labelled time workflow nets (LTWNs) is also defined based on LTPNs. Cross-organisational labelled time workflow nets (CLTWNs) is then defined based on LTWNs. Third, the article proposes the notion of OR-silent CLTWNS and a verifying approach to the soundness of LTWNs and CLTWNs. Finally, this article illustrates how to use the proposed method by a simple example. The purpose of this research is to establish a formal method of modelling and analysis of workflow systems for LSC. This study initiates a new perspective of research on cross-organisational workflow management and promotes operation management of LSC in real world settings.

Working towards an international consensus on criteria for assessing internet gaming disorder: a critical commentary on Petry et al. (2014)

OpenAIRE

GRIFFITHS, MARK D.; VAN ROOIJ, ANTONIUS J.; KARDEFELT-WINTHER, DANIEL; STARCEVIC, VLADAN; KIRÁLY, ORSOLYA; PALLESEN, STÅLE; MÜLLER, KAI; DREIER, MICHAEL; CARRAS, MICHELLE; PRAUSE, NICOLE; KING, DANIEL L.; ABOUJAOUDE, ELLIAS; KUSS, DARIA J.; PONTES, HALLEY M.; FERNANDEZ, OLATZ LOPEZ

2016-01-01

This commentary paper critically discusses the recent debate paper by Petry et al. (2014) that argued there was now an international consensus for assessing Internet Gaming Disorder (IGD). Our collective opinions vary considerably regarding many different aspects of online gaming. However, we contend that the paper by Petry and colleagues does not provide a true and representative international community of researchers in this area. This paper critically discusses and provides ...

Perti Net-Based Workflow Access Control Model%基于Perti网的工作流访问控制模型研究

Institute of Scientific and Technical Information of China (English)

陈卓; 骆婷; 石磊; 洪帆

2004-01-01

Access control is an important protection mechanism for information systems.This paper shows how to make access control in workflow system.We give a workflow access control model (WACM) based on several current access control models.The model supports roles assignment and dynamic authorization.The paper defines the workflow using Petri net.It firstly gives the definition and description of the workflow, and then analyzes the architecture of the workflow access control model (WACM).Finally, an example of an e-commerce workflow access control model is discussed in detail.

Modeling integrated cellular machinery using hybrid Petri-Boolean networks.

Directory of Open Access Journals (Sweden)

Natalie Berestovsky

Full Text Available The behavior and phenotypic changes of cells are governed by a cellular circuitry that represents a set of biochemical reactions. Based on biological functions, this circuitry is divided into three types of networks, each encoding for a major biological process: signal transduction, transcription regulation, and metabolism. This division has generally enabled taming computational complexity dealing with the entire system, allowed for using modeling techniques that are specific to each of the components, and achieved separation of the different time scales at which reactions in each of the three networks occur. Nonetheless, with this division comes loss of information and power needed to elucidate certain cellular phenomena. Within the cell, these three types of networks work in tandem, and each produces signals and/or substances that are used by the others to process information and operate normally. Therefore, computational techniques for modeling integrated cellular machinery are needed. In this work, we propose an integrated hybrid model (IHM that combines Petri nets and Boolean networks to model integrated cellular networks. Coupled with a stochastic simulation mechanism, the model simulates the dynamics of the integrated network, and can be perturbed to generate testable hypotheses. Our model is qualitative and is mostly built upon knowledge from the literature and requires fine-tuning of very few parameters. We validated our model on two systems: the transcriptional regulation of glucose metabolism in human cells, and cellular osmoregulation in S. cerevisiae. The model produced results that are in very good agreement with experimental data, and produces valid hypotheses. The abstract nature of our model and the ease of its construction makes it a very good candidate for modeling integrated networks from qualitative data. The results it produces can guide the practitioner to zoom into components and interconnections and investigate them

Business process modeling using Petri nets

NARCIS (Netherlands)

Hee, van K.M.; Sidorova, N.; Werf, van der J.M.E.M.; Jensen, K.; Aalst, van der W.M.P.; Balbo, G.; Koutny, M.; Wolf, K.

2013-01-01

Business process modeling has become a standard activity in many organizations. We start with going back into the history and explain why this activity appeared and became of such importance for organizations to achieve their business targets. We discuss the context in which business process

Special Section on Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

2007-01-01

The development of modern distributed systems is an extremely challenging task, because the concurrency and non-determinism create an astronomical number of possible system states and execution sequences. Hence, it is easy for the human designer to miss important interaction patterns, leading...

Networks of Cells and Petri Nets

OpenAIRE

Bernardini, Francesco; Gheorgue, Marian; Margenstern, Maurice; Verlan, Sergey

2007-01-01

We introduce a new class of P systems, called networks of cells, with rules allowing several cells to simultaneously interact with each other in order to produce some new objects inside some other output cells. We define different types of behavior for networks of cells by considering alternative strategies for the application of the rules: sequential application, free parallelism, maximal parallelism, locally-maximal parallelism and minimal parallelism. We devise a way for tra...

Analysis of the monitoring system for the spallation neutron source 'SINQ'

International Nuclear Information System (INIS)

Badreddin, E.

1998-01-01

Petri Net models (PN) and Fault-Tree Analysis (FTA) are employed for the purpose of reliability analysis of the spallation neutron source SINQ. The monitoring and shut-down system (SDS) structure is investigated using a Petri-Net model. The reliability data are processed using a Fault-Tree model of the dominant part. Finally, suggestions for the improvement of system availability are made. (author)

Nano Petri dishes: a new polystyrene platform for studying cell-nanoengineered surface interactions

International Nuclear Information System (INIS)

Cha, Kyoung Je; Na, Moon-Hee; Kim, Hyung Woo; Kim, Dong Sung

2014-01-01

In this study, we fabricated and fully characterized a new type of polystyrene (PS) cell-culture platform containing nanoengineered surfaces (NES), referred to as a nano Petri dish, which can be used at the transition stage of basic cell–NES interaction studies for clinical applications. Nano-injection molding in this study was used for the mass production of the nano Petri dish having nanopore arrays. The effects of processing parameters of the injection molding on the replication quality of the nanopore arrays were quantitatively evaluated by means of design of experiments based on the Taguchi method. This allowed efficient and reliable cell culture studies by providing large numbers of the same dishes, in addition to removing the fixation step of the NES plates inside the cell-culture container. Physical, chemical and mechanical properties of the NES, as well as cell behavior including attachment and proliferation of human osteosarcoma MG-63 cells on the NES, were then characterized, with and without the oxygen plasma surface treatment. (paper)

Nano Petri dishes: a new polystyrene platform for studying cell-nanoengineered surface interactions

Science.gov (United States)

Cha, Kyoung Je; Na, Moon-Hee; Kim, Hyung Woo; Kim, Dong Sung

2014-05-01

In this study, we fabricated and fully characterized a new type of polystyrene (PS) cell-culture platform containing nanoengineered surfaces (NES), referred to as a nano Petri dish, which can be used at the transition stage of basic cell-NES interaction studies for clinical applications. Nano-injection molding in this study was used for the mass production of the nano Petri dish having nanopore arrays. The effects of processing parameters of the injection molding on the replication quality of the nanopore arrays were quantitatively evaluated by means of design of experiments based on the Taguchi method. This allowed efficient and reliable cell culture studies by providing large numbers of the same dishes, in addition to removing the fixation step of the NES plates inside the cell-culture container. Physical, chemical and mechanical properties of the NES, as well as cell behavior including attachment and proliferation of human osteosarcoma MG-63 cells on the NES, were then characterized, with and without the oxygen plasma surface treatment.

La tempesta napoletana oltre Eduardo De Filippo: una nota sulle riscritture di Tato Russo e Arnolfo Petri

Directory of Open Access Journals (Sweden)

Armando Rotondi

2016-06-01

Full Text Available Il seguente contributo intende analizzare brevemente alcuni elementi delle riscritture in napoletano de La tempesta di William Shakespeare effettuate da Tato Russo e Arnolfo Petri. In particolare, si noteranno l’influenza e le differenze con l’approccio di Eduardo De Filippo, autore di una celebre traduzione del capolavoro shakespeariano nel 1984. || The following contribution aims at analysing some elements of the re-writings in Neapolitan of William Shakespeare’s The Tempest made by Tato Russo and Arnolfo Petri. In particular, I will focus on De Filippo’s influence and on the differences between his 1984 translation of the Shakespearean masterpiece and Russo’s and Petri’s own approach.

From Task Descriptions via Coloured Petri Nets Towards an Implementation of a New Electronic Patient Record

DEFF Research Database (Denmark)

Jørgensen, Jens Bæk; Lassen, Kristian Bisgaard; van der Aalst, Willibrordus Martinus Pancratius

2008-01-01

help to validate and elicit requirements. The second CPN model is a Colored Workflow Net (CWN). The CWN is derived from the EUC. Together, the EUC and the CWN are used to close the gap between the given requirements specification and the realization of these requirements with the help of an IT system......We consider a given specification of functional requirements for a new electronic patient record system for Fyn County, Denmark. The requirements are expressed as task descriptions, which are informal descriptions of work processes to be supported. We describe how these task descriptions are used...

Development of a tool for knowledge base verification of expert system based on Design/CPN

International Nuclear Information System (INIS)

Kim, Jong Hyun

1998-02-01

Verification is a necessary work in developing a reliable expert system. Verification is a process aimed at demonstrating whether a system meets it's specified requirements. As expert systems are used in various applications, the knowledge base verification of systems takes an important position. The conventional Petri net approach that has been studied recently in order to verify the knowledge base is found that it is inadequate to verify the knowledge base of large and complex system, such as alarm processing system of nuclear power plant. Thus, we propose an improved method that models the knowledge base as enhanced colored Petri net. In this study, we analyze the reachability and the error characteristics of the knowledge base. Generally, verification process requires computational support by automated tools. For this reason, this study developed a tool for knowledge base verification based on Design/CPN, which is a tool for editing, modeling, and simulating Colored Petri net. This tool uses Enhanced Colored Petri net as a modeling method. By applying this tool to the knowledge base of nuclear power plant, it is noticed that it can successfully check most of the anomalies that can occur in a knowledge base

Formalization, implementation, and modeling of institutional controllers for distributed robotic systems.

Science.gov (United States)

Pereira, José N; Silva, Porfírio; Lima, Pedro U; Martinoli, Alcherio

2014-01-01

The work described is part of a long term program of introducing institutional robotics, a novel framework for the coordination of robot teams that stems from institutional economics concepts. Under the framework, institutions are cumulative sets of persistent artificial modifications made to the environment or to the internal mechanisms of a subset of agents, thought to be functional for the collective order. In this article we introduce a formal model of institutional controllers based on Petri nets. We define executable Petri nets-an extension of Petri nets that takes into account robot actions and sensing-to design, program, and execute institutional controllers. We use a generalized stochastic Petri net view of the robot team controlled by the institutional controllers to model and analyze the stochastic performance of the resulting distributed robotic system. The ability of our formalism to replicate results obtained using other approaches is assessed through realistic simulations of up to 40 e-puck robots. In particular, we model a robot swarm and its institutional controller with the goal of maintaining wireless connectivity, and successfully compare our model predictions and simulation results with previously reported results, obtained by using finite state automaton models and controllers.

Working towards an international consensus on criteria for assessing Internet Gaming Disorder: a critical commentary on Petry et al. (2014) [forthcoming

OpenAIRE

Griffiths, MD; Van Rooij, AJ; Kardefelt-Winther, D; Starcevic, V; Király, O; Pallesen, S; Müller, K; Dreier, M; Carras, M; Prause, N; King, DL; Aboujaoude, E; Kuss, DJ; Pontes, HM; Lopez-Fernandez, O

2016-01-01

This commentary paper critically discusses the recent debate paper by Petry et al. (2014) that argued there was now an international consensus for assessing Internet Gaming Disorder (IGD). Our collective opinions vary considerably regarding many different aspects of online gaming. However, we contend that the paper by Petry and colleagues does not provide a true and representative international community of researchers in this area. This paper critically discusses and provides commentary on (...

U-Net/SLE: A Java-Based User-Customizable Virtual Network Interface

Directory of Open Access Journals (Sweden)

Matt Welsh

1999-01-01

Full Text Available We describe U‐Net/SLE (Safe Language Extensions, a user‐level network interface architecture which enables per‐application customization of communication semantics through downloading of user extension applets, implemented as Java classfiles, to the network interface. This architecture permits applications to safely specify code to be executed within the NI on message transmission and reception. By leveraging the existing U‐Net model, applications may implement protocol code at the user level, within the NI, or using some combination of the two. Our current implementation, using the Myricom Myrinet interface and a small Java Virtual Machine subset, allows host communication overhead to be reduced and improves the overlap of communication and computation during protocol processing.

Elaborating Naturalized Critical Realism: Response to Ruth Groff, Dave Elder-Vass, Daniel Little and Petri Ylikoski

Directory of Open Access Journals (Sweden)

Kaidesoja Tuukka

2015-09-01

Full Text Available This paper is a reply to the discussions of Ruth Groff, Dave Elder-Vass, Daniel Little, and Petri Ylikoski of Tuukka Kaidesoja (2013: Naturalizing Critical Realist Social Ontology (London: Routledge.

Developing Software to Use Parallel Processing Effectively

Science.gov (United States)

1988-10-01

in which description of an algorithm is strictly separated from its implementation details. 3-22 EDDA is a dataflow design language with graphical...notation sim- ilar to SADT and a semantic structure resembling Petri-Nets. Unlike Petri-Nets, EDDA can represent recursion. An EDDA design contains...predefined functional elements and obeys strict semantic rules, and can therefore be compiled into executable code. Programs are built in EDDA by

Of watchdogs and safe havens: control mechanisms and/in online sacred spaces

Directory of Open Access Journals (Sweden)

Alexander Darius Ornella

2013-01-01

Full Text Available ‘Die große Schlacht. Der Hass des Satans auf Benedikt XVI. Non prae­valebunt’ is the headline of an article the Austrian-based and Catholic news portal, kath.net, published in early June 2012. It is about how badly and unfairly the media treat the Catholic Church and its official representatives in the wake of the so-called ‘Vatileaks’ scandal and it reasons that Satan is behind the attacks of the media, society, popular culture, on saintly figures such as Pope Benedict XVI. ‘Gegen die Diktatur des Relativismus’ is another article published on the same platform in the context of a conference hosted by the Catholic Heiligenkreuz monastery. On the forum kath.net, powerful language is employed to draw the faithful in, to make them feel themselves to be safe within a community of like-minded people in the midst of turmoil. News portals and message boards such as kath.net create safe spaces within a world whose culture, values, and morals are not only not understood but despised. The analysis is informed by critical discourse analysis and based on Paul Ricœur’s understanding of narratives and how narratives create worlds. As a first step, the concept of space and Ricœur’s understanding of narrative identity are discussed. After an introduction to the news portal kath.net, a close reading of some articles shows how these safe spaces are created and guarded. To conclude, a reflection on the implications of the self-understanding of kath.net and some of its user base on the understanding of hierarchy and the role of theology in the Church, is provided.

Ritning som byggande: Lewerentz och ritningarna till S:t Petri

DEFF Research Database (Denmark)

Foote, Jonathan

2016-01-01

from the site and into drawing studios. Today, with complex tools of virtual communication between builders and designers, it is quite common for an architect to design buildings without ever setting foot on the construction site. In contrast to the strong distinction between drawing and building made...... and S:t Petri. Through close collaborations with materials and builders, Lewerentz translated his ideas into an architecture that was deeply personal. What is more, such an approach was thoroughly inseparable from his unique method of engaging construction through drawing and sketching. Upon examining...

Método para el Modelado y Prueba de Diagramas de Actividades Mediante Redes de Petri

Directory of Open Access Journals (Sweden)

Lionel Baquero Hernández

2015-11-01

Full Text Available Las redes de Petri son ideales para describir y estudiar sistemas que procesan información y con características concurrentes, asíncronas, distribuidas, paralelas, no determinísticas y/o estocásticas. . Sin embargo, la teoría clásica de estas redes se enfrenta al desafío de adecuarse a las nuevas necesidades de los sistemas informáticos que los ingenieros diseñan en la actualidad. Un diagrama de actividades representa una secuencia de actividades. Podría aplicarse a cualquier propósito, pero se considera especialmente útil para visualizar los flujos de trabajo y los procesos del negocio, o casos de uso. El presente trabajo se ha desarrollado con el objetivo de diseñar un método para el modelado y prueba de diagramas de actividades mediante redes de Petri. El método propuesto brinda una serie de pasos necesarios para modelar un diagrama de actividades con redes de Petri y a partir de dicha red obtener una representación matemática de la misma. Esta representación matemática se utiliza para con ella realizar una serie de operaciones basadas en el marcaje de la red que permiten realizar pruebas al diagrama. Este método es capaz de identificar errores comunes que se cometen en el modelado de los diagramas de actividades, lo cual se demostró a través del método de experimentación.

Study on deterministic response time design for a class of nuclear Instrumentation and Control systems

International Nuclear Information System (INIS)

Chen, Chang-Kuo; Hou, Yi-You; Luo, Cheng-Long

2012-01-01

Highlights: ► An efficient design procedure for deterministic response time design of nuclear I and C system. ► We model the concurrent operations based on sequence diagrams and Petri nets. ► The model can achieve the deterministic behavior by using symbolic time representation. ► An illustrative example of the bistable processor logic is given. - Abstract: This study is concerned with a deterministic response time design for computer-based systems in the nuclear industry. In current approach, Petri nets are used to model the requirement of a system specified with sequence diagrams. Also, the linear logic is proposed to characterize the state of changes in the Petri net model accurately by using symbolic time representation for the purpose of acquiring deterministic behavior. An illustrative example of the bistable processor logic is provided to demonstrate the practicability of the proposed approach.

Avaliação do desempenho logístico do transporte rodoviário de madeira utilizando rede de petri em uma empresa florestal de Minas Gerais Evalution of logistic performance of wood hauling using petri net in a forest industry of Minas Gerais

Directory of Open Access Journals (Sweden)

Raiane Ribeiro Machado

2006-12-01

wood transport cycle time consists of wood loading, wood hauling, wood unloading, garage and wood unhauling. A cellulose producing company in the State of Minas Gerais was used as case study. Initially, the logistics and supply chain of the company was diagnosed to know the main existent obstacles along the chain; defining their preliminary vary key parameters, based on the characterization of their structure and operation; finally, the main directors that condition their efficiency and competitiveness were identified and evaluated. The model of chain logistics of wood transport used the Temporal Petri Net for working with two times that correspond to a sensitization period. Their properties are as follows: simulation (working with hypothetical scenarios, dynamic (exit values depend on the entrance values; determinist (exit variables are not random; continuous (time is measured by real numbers; and temporal in the transitions. Scenarios, with the same variations in the two wood-producing regionals were created, and simulations with the JARP and ARP software were carried out to evaluate the operational and economic performance. The variations applied to the scenarios were: improvement of the forest roads; increase of loader numbers, and improvement of garage efficiency. For both regionals, the scenario with the three variations (Scenario 7 presented the largest reduction in cycle times of wood transport in relation to the current situation, being 19.24% and 21.48%, respectively, for Rio Doce and Cocais das Estrelas. The analyzed operational cost is the value paid for the freight, not including the investment costs. Both regionals, Rio Doce and Cocais das Estrelas, presented a larger reduction in the Scenario 7, of 20.09% and 21.22%, respectively.

Sufficient and Necessary Condition to Decide Compatibility for a Class of Interorganizational Workflow Nets

Directory of Open Access Journals (Sweden)

Guanjun Liu

2015-01-01

Full Text Available Interorganizational Workflow nets (IWF-nets can well model many concurrent systems such as web service composition, in which multiple processes interact via sending/receiving messages. Compatibility of IWF-nets is a crucial criterion for the correctness of these systems. It guarantees that a system has no deadlock, livelock, or dead tasks. In our previous work we proved that the compatibility problem is PSPACE-complete for safe IWF-nets. This paper defines a subclass of IWF-nets that can model many cases about interactions. Necessary and sufficient condition is presented to decide their compatibility, and it depends on the net structures only. Finally, an algorithm is developed based on the condition.

Application of the monazite radiation source to the petri dish-type cloud chamber and the influence of several factors on occurrence of tracks

International Nuclear Information System (INIS)

Hayakawa, Issei; Sago, Yutaka; Mori, Chizuo

2012-01-01

Monazite radiation source (2.5 mmΦ) proved to be useful as a radiation source of cloud chamber without the dispersion of powder or its adhesion because of a sintered body. After the track appeared within one minute after having put the petri dish on the dry ice, the number increased rapidly followed by the tendency to decrease gradually after that. The tracks can be observed for about 20 minutes after cooled with dry ice. The size of dry ice should be chosen to enter the inside of the bottom edge of the petri dish. The same number of tracks as using conventional mantle radiation source was obtained by utilizing 3 pieces of monazite sintered body separated mutually by about 7.5 mm. Hence the petri dish-type cloud chamber with the monazite sintered body as radiation source revealed to make the observation of track easy and prompt. (author)

Modeling humanoid swarm robots with petri nets

OpenAIRE

Maharjan, Bikee

2015-01-01

Master's thesis in Computer science Robots have become a hot topic in today‟s electronic world. There are many definitions for it. One of the definition in Oxford dictionary states “a robot is a machine capable for carrying out a complex series of action automatically especially one programmable by a computer”. This paper deals with a special kind of robot, which is also known as humanoid robot. These robots are replication of human beings with head, torso, arms and legs. A model of hum...

SOFTWARE DESIGN MODELLING WITH FUNCTIONAL PETRI NETS

African Journals Online (AJOL)

Dr Obe

the system, which can be described as a set of conditions. ... FPN Software prototype proposed for the conventional programming construct: if-then-else ... mathematical modeling tool allowing for ... methods and techniques of software design.

Epsilon. A System Description Language

DEFF Research Database (Denmark)

Jensen, Kurt; Kyng, Morten

This paper discusses the use of Petri nets as a semantic tool in the design of languages and in the construction and analysis of system descriptions. The topics treated are: -- Languages based on nets. -- The problem of time in nets. -- Nets and related models. -- Nets and formal semantics...

Opening the stable door: new initiatives at the Petrie Museum of Egyptian Archaeology

Directory of Open Access Journals (Sweden)

Sally MacDonald

2000-11-01

Full Text Available The Petrie Museum ut UCL contains u world-class collection of Egyptian objects that ranges chronologically from early prehistoric to Islamic times, but it is inadequately housed and remains little known outside Egyptology. It has now been designated us of national importance and its stuff have ambitious plans to provide greater access, via the Internet and in other ways, to the 80000 objects it contains.

Generalized Asynchronous Systems

Directory of Open Access Journals (Sweden)

E. S. Kudryashova

2012-01-01

Full Text Available The paper consider a mathematical model of a concurrent system, the special case of which is an asynchronous system. Distributed asynchronous automata are introduced here. It is proved that Petri nets and transition systems with independence can be considered as distributed asynchronous automata. Time distributed asynchronous automata are defined in a standard way by correspondence which relates events with time intervals. It is proved that the time distributed asynchronous automata generalize time Petri nets and asynchronous systems.

A Method to Preclude Moisture Condensation in Plated Tissue Cultures

Science.gov (United States)

Alex M. Diner

1992-01-01

Excessive condensate normally accumulates in in vitro-illuminated petri dishes containing plant tissue cultures, causing avariety of problems. A dark-colored rubber net-mesh placed over the petri dishes prevented such condensation, even when charcoal-supplemented media are used under high light intensity in a growth chamber.

Gods, Germs, and Petri Dishes: Toward a Nonsecular Medical Anthropology.

Science.gov (United States)

Roberts, Elizabeth F S

2016-01-01

This commentary calls on medical anthropology to become programmatically non-secular. Despite recent anthropological critiques of secularity, within and outside of anthropology, most contemporary medical anthropologists continue to leave deities and religiosity out of their examinations of healing practices, especially in their accounts of biomedicine. Through a critical, relational constructionist lens, which traces how all entities are both constructed and real, a non-secular medical anthropology would insist that when deities are part of medical practice, they are integral to analysis. Importantly then, within the symmetrical nature of this same constructionist lens, biomedical entities like germs and petri dishes need to be accounted for just as much as deities.

Developing a Formal Specification for the Mission Systems of a Maritime Surveillance Aircraft

DEFF Research Database (Denmark)

Petrucci, Laure; Billington, Jonathan; Kristensen, Lars Michael

2003-01-01

The mission system of an aircraft is a complex real-time distributed system consisting of a mission control computer, different kinds of devices interconnected by a number of serial data buses. The complexity and real-time requirements of mission systems have motivated research into the applicati...... system with Coloured Petri Nets and analysed the model using state spaces. Here, we describe how this model was refined and modified to obtain a Coloured Petri Net model for the AP-3C Orion maritime surveillance aircraft....

A study on constructing a machine-maintenance training system based on virtual reality technology

International Nuclear Information System (INIS)

Ishii, H.; Kashiwa, K.; Tezuka, T.; Yoshikawa, H.

1997-01-01

The development of a VR based training system are presented for teaching disassembling procedures of mechanical machines used in nuclear power plant. The methods of Petri net model for describing trainees' plausible actions in the disassembling process and reduce a right sequence of action sequence are developed as well as realization of the related Petri net editor and the demonstration of the developed VR based training system was demonstrated by example practice of disassembly simulation of check valve. Moreover, the needed future works are also discussed

MMPM - Mars MetNet Precursor Mission

Science.gov (United States)

Harri, A.-M.; Schmidt, W.; Pichkhadze, K.; Linkin, V.; Vazquez, L.; Uspensky, M.; Polkko, J.; Genzer, M.; Lipatov, A.; Guerrero, H.; Alexashkin, S.; Haukka, H.; Savijarvi, H.; Kauhanen, J.

2008-09-01

MetNet Mars Mission will provide a crucial support for the safety of large landing missions in general and manned Mars missions in particular. Accurate knowledge of atmospheric conditions and weather data is essential to guarantee safe landings of the forthcoming Mars mission elements. The MetNet Mars Mission is exactly this type of tool that is needed both for the Martian atmospheric science as well as for the mission safety issues.

Manager- bändikarjääri disainija ja kokkusõlmija / Paul Cheeetham, Tapio Korjus, Petri H. Lunden ...[jt.

Index Scriptorium Estoniae

Cheetham, Paul

2010-01-01

Muusikamanageride Paul Cheethami, Tapio Korjuse, Petri H. Lundeni, Kari Pössi ja Rasmus Stolbergi arvamusi oma tööst ja nõuannetest eesti ansamblitele, kes tahavad oma karjääri teha rahvusvahelisel areenil

Using Petri nets for modeling enterprise integration patterns

NARCIS (Netherlands)

Fahland, D.; Gierds, C.

2012-01-01

Enterprise Integration Patterns are a collection of widely used patterns for integrating enterprise applications and business processes. These patterns informally represent typical design decisions for connecting enterprise applications. For the set of patterns collected by Hohpe and Woolf in

Petri net transformations for business processes : a survey

NARCIS (Netherlands)

Lohmann, N.; Verbeek, H.M.W.; Dijkman, R.M.; Jensen, K.; Aalst, van der W.M.P.

2009-01-01

In Process-Aware Information Systems, business processes are often modeled in an explicit way. Roughly speaking, the available business process modeling languages can be divided into two groups.Languages from the first group are preferred by academic people but shunned by business people, and

Code Generation from Pragmatics Annotated Coloured Petri Nets

DEFF Research Database (Denmark)

Simonsen, Kent Inge

limited work has been done on transforming CPN model to protocol implementations. The goal of the thesis is to be able to automatically generate high-quality implementations of communication protocols based on CPN models. In this thesis, we develop a methodology for generating implementations of protocols...... third party libraries and the code should be easily usable by third party code. Finally, the code should be readable by developers with expertise on the considered platforms. In this thesis, we show that our code generation approach is able to generate code for a wide range of platforms without altering...... such as games and rich web applications. Finally, we conclude the evaluation of the criteria of our approach by using the WebSocket PA-CPN model to show that we are able to verify fairly large protocols....

As Placas de Petri de Samuel

Directory of Open Access Journals (Sweden)

Araújo, Maria Valéria Pereira de

2014-12-01

Full Text Available The case teaching "The Petri dishes of Samuel" mentions a real situation occurred in a small business Medical Laboratory located in the city of Natal-RN. The dilemma of the case comes to a decision-making situation involving João, Director of the Laboratory Tércio Rosado and responsible for the human resources sector of the organization. The case is narrated from his point of view which faces a situation where one employee who works at the company for 25 years can not get adapted to the new technologies of the Medical Laboratory area, although the employee possesses behavioral and attitudinal competences which sets it apart from other professionals. After several attempts of training processes, trying to make Samuel adapt his behavior to the new technological requirements of the position, none of them were successful. Facing the situation the Director had a dilemma to solve: keep him in the company or not? If the company remains the employee, it might discourage the learning development of the other ones? On the other hand, the company would have other alternatives of training him in order to develop the required skills? What could be done? The case was constructed from observational data and informal conversations with employees and with the former owners of the company. Fictitious names were used to preserve the identity of the involved.

Analysis of ewe’s milk by FT Near Infrared spectroscopy: measurement of samples on Petri dishes in reflectance mode

Directory of Open Access Journals (Sweden)

Květoslava Šustová

2006-01-01

Full Text Available Our work deals with a possibility of determination of basic composition (dry matter, fat, protein, casein, lactose and urea nitrogen of ewe’s milk and colostrum by FT NIR spectroscopy. Samples of milk were warmed to 40 °C, agitated, cooled to 20 °C, transferred into Petri dishes and analysed by reference methods and by FT NIR in reflectance mode. The measured area was spaced by a metallic mirror. Statistically significant differences between the reference values and the calculated values of NIR were not found (p=0.05. Results of calibration for ewe’s milk determined the highest correlation coefficients: dry matter 0.983, fat 0.989, true protein 0.997, casein 0.977, lactose 0.980 and urea nitrogen 0.973. The study showed that NIRS method, when samples of milk are measured on Petri dishes, is a useful technique for the prediction of dry matter, fat, protein and casein in ewe’s milk.

Open-Ended Waveguide Measurement and Numerical Simulation of the Reflectivity of Petri Dish Supported Skin Cell Monolayers in the mm-wave Range

Science.gov (United States)

Beneduci, Amerigo; Chidichimo, Giuseppe

2012-05-01

Open-ended waveguide reflectometry is a promising tool for permittivity and other material properties calculation at mm-waves (30-300 GHz). Measurement of the reflection coefficient does not require sample manipulation, allowing in vivo and in vitro non destructive studies on cells. Here we used this technique for measuring the power reflection coefficient (reflectivity) of water and Petri dish supported human skin melanoma and keratinocyte cell cultures, in the 53-72 GHz frequency range. The dependence of the reflectivity on polystyrene or glass thickness of the Petri base plate and on the cell layer thickness was analyzed. Permittivity data were then easily retrieved by using a plane wave-dominant mode approach for formulating the reflectivity at the aperture of the flange-mounted open-ended rectangular waveguide probe. Limits and validity of such an approximate approach were analyzed and compared with full-wave near field formulations for which magnitude and phase of the reflection coefficient must be measured and solved using complicated systems of integral equations and extensive numerical calculation. Finally, Petri dish reflectivity measured by the open-ended waveguide method was compared with that numerically simulated under far-field exposure conditions used in a large number of in vitro studies. Such an analysis showed that, under certain conditions, open-ended reflectivity values approach the far field ones.

Working towards an international consensus on criteria for assessing internet gaming disorder: a critical commentary on Petry et al. (2014)

Science.gov (United States)

GRIFFITHS, MARK D.; VAN ROOIJ, ANTONIUS J.; KARDEFELT-WINTHER, DANIEL; STARCEVIC, VLADAN; KIRÁLY, ORSOLYA; PALLESEN, STÅLE; MÜLLER, KAI; DREIER, MICHAEL; CARRAS, MICHELLE; PRAUSE, NICOLE; KING, DANIEL L.; ABOUJAOUDE, ELLIAS; KUSS, DARIA J.; PONTES, HALLEY M.; FERNANDEZ, OLATZ LOPEZ; NAGYGYORGY, KATALIN; ACHAB, SOPHIA; BILLIEUX, JOËL; QUANDT, THORSTEN; CARBONELL, XAVIER; FERGUSON, CHRISTOPHER J.; HOFF, RANI A.; DEREVENSKY, JEFFREY; HAAGSMA, MARIA C.; DELFABBRO, PAUL; COULSON, MARK; HUSSAIN, ZAHEER; DEMETROVICS, ZSOLT

2017-01-01

This commentary paper critically discusses the recent debate paper by Petry et al. (2014) that argued there was now an international consensus for assessing Internet Gaming Disorder (IGD). Our collective opinions vary considerably regarding many different aspects of online gaming. However, we contend that the paper by Petry and colleagues does not provide a true and representative international community of researchers in this area. This paper critically discusses and provides commentary on (i) the representativeness of the international group that wrote the ‘consensus’ paper, and (ii) each of the IGD criteria. The paper also includes a brief discussion on initiatives that could be taken to move the field towards consensus. It is hoped that this paper will foster debate in the IGD field and lead to improved theory, better methodologically designed studies, and more robust empirical evidence as regards problematic gaming and its psychosocial consequences and impact. PMID:26669530

A Sweep-Line Method for State Space Exploration

DEFF Research Database (Denmark)

Christensen, Søren; Kristensen, Lars Michael; Mailund, Thomas

2001-01-01

generation, since these states can never be reached again. This in turn reduces the memory used for state space storage during the task of verification. Examples of progress measures are sequence numbers in communication protocols and time in certain models with time. We illustrate the application...... of the method on a number of Coloured Petri Net models, and give a first evaluation of its practicality by means of an implementation based on the Design/CPN state space tool. Our experiments show significant reductions in both space and time used during state space exploration. The method is not specific...... to Coloured Petri Nets but applicable to a wide range of modelling languages....

Translating Unstructured Workflow Processes to Readable BPEL: Theory and Implementation

DEFF Research Database (Denmark)

van der Aalst, Willibrordus Martinus Pancratius; Lassen, Kristian Bisgaard

2008-01-01

and not easy to use by end-users. Therefore, we provide a mapping from Workflow Nets (WF-nets) to BPEL. This mapping builds on the rich theory of Petri nets and can also be used to map other languages (e.g., UML, EPC, BPMN, etc.) onto BPEL. In addition to this we have implemented the algorithm in a tool called...... WorkflowNet2BPEL4WS....

Horizontal ichthyoplankton tow-net system with unobstructed net opening

Science.gov (United States)

Nester, Robert T.

1987-01-01

The larval fish sampler described here consists of a modified bridle, frame, and net system with an obstruction-free net opening and is small enough for use on boats 10 m or less in length. The tow net features a square net frame attached to a 0.5-m-diameter cylinder-on-cone plankton net with a bridle designed to eliminate all obstructions forward of the net opening, significantly reducing currents and vibrations in the water directly preceding the net. This system was effective in collecting larvae representing more than 25 species of fish at sampling depths ranging from surface to 10 m and could easily be used at greater depths.

Higher-moment measurements of net-kaon, net-charge and net-proton multiplicity distributions at STAR

International Nuclear Information System (INIS)

Sarkar, Amal

2014-01-01

In this paper, we report the measurements of the various moments, such as mean, standard deviation (σ), skewness (S) and kurtosis (κ) of the net-kaon, net-charge and net-proton multiplicity distributions at mid-rapidity in Au + Au collisions from √(s NN )=7.7 to 200 GeV with the STAR experiment at RHIC. This work has been done with the aim to locate the critical point on the QCD phase diagram. These moments and their products are related to the thermodynamic susceptibilities of conserved quantities such as net baryon number, net charge, and net strangeness as well as to the correlation length of the system which diverges in an ideal infinite thermodynamic system at the critical point. For a finite system, existing for a finite time, a non-monotonic behavior of these variables would indicate the presence of the critical point. Furthermore, we also present the moment products Sσ, κσ 2 of net-kaon, net-charge and net-proton multiplicity distributions as a function of collision centrality and energy. The energy and the centrality dependence of higher moments and their products have been compared with different models

Model-based prototyping of an interoperability protocol for mobile ad-hoc networks

NARCIS (Netherlands)

Kristensen, L.M.; Westergaard, M.; Norgaard, P.C.; Romijn, J.; Smith, G.; Pol, van de J.

2005-01-01

We present an industrial project conducted at Ericsson Danmark A/S, Telebit where formal methods in the form of Coloured Petri Nets (CP-nets or CPNs) have been used for the specification of an interoperability protocol for routing packets between fixed core networks and mobile ad-hoc networks. The

Specification and Validation of an Edge Router Discovery Protocol for Mobile Ad Hoc Networks

DEFF Research Database (Denmark)

Kristensen, Lars Michael; Jensen, Kurt

2004-01-01

We present an industrial project at Ericsson Telebit A/S where Coloured Petri Nets (CP-nets or CPNs) have been used for the design and specification of an edge router discovery protocol for mobile ad-hoc networks. The Edge Router Discovery Protocol (ERDP) supports an edge router in a stationary...

Net-baryon-, net-proton-, and net-charge kurtosis in heavy-ion collisions within a relativistic transport approach

International Nuclear Information System (INIS)

Nahrgang, Marlene; Schuster, Tim; Stock, Reinhard; Mitrovski, Michael; Bleicher, Marcus

2012-01-01

We explore the potential of net-baryon, net-proton and net-charge kurtosis measurements to investigate the properties of hot and dense matter created in relativistic heavy-ion collisions. Contrary to calculations in a grand-canonical ensemble we explicitly take into account exact electric and baryon charge conservation on an event-by-event basis. This drastically limits the width of baryon fluctuations. A simple model to account for this is to assume a grand-canonical distribution with a sharp cut-off at the tails. We present baseline predictions of the energy dependence of the net-baryon, net-proton and net-charge kurtosis for central (b≤2.75 fm) Pb+Pb/Au+Au collisions from E lab =2A GeV to √(s NN )=200 GeV from the UrQMD model. While the net-charge kurtosis is compatible with values around zero, the net-baryon number decreases to large negative values with decreasing beam energy. The net-proton kurtosis becomes only slightly negative for low √(s NN ). (orig.)

Successful Implantation of a Left Ventricular Assist Device After Treatment With the Paracor HeartNet.

Science.gov (United States)

Schweiger, Martin; Stepanenko, Alexander; Potapov, Evgenji; Drews, Thorsten; Hetzer, Roland; Krabatsch, Thomas

2010-01-01

The Paracor HeartNet, a ventricular constraint device for the treatment of heart failure (HF), is implanted through a left lateral thoracotomy. It envelopes the heart like a mesh "bag." This method of application raises the question of whether adhesions with the pericardium allow the safe implantation of a left ventricular assist device (LVAD) if HF worsens. A male patient who had undergone implantation of the Paracor HeartNet 42 months earlier presented with advanced HF for cardiac transplantation. The patient's condition deteriorated, and because no suitable organ for transplantation was available, implantation of an LVAD became necessary. Surgery was performed via a median sternotomy without complications. No severe adhesions were found. This is the first report on "how to do" LVAD implantation after Paracor HeartNet implantation with images and information about cutting the constraint. Because the Paracor HeartNet is "wrapped" around the heart, concerns persist that severe adhesions with the pericardium might occur. In this case, LVAD implantation after therapy with the Paracor HeartNet was without complications, and the expected massive adhesions were absent.

modeling workflow management in a distributed computing system

African Journals Online (AJOL)

Dr Obe

communication system, which allows for computerized support. ... Keywords: Distributed computing system; Petri nets;Workflow management. 1. ... A distributed operating system usually .... the questionnaire is returned with invalid data,.

Monetary benefits of preventing childhood lead poisoning with lead-safe window replacement.

Science.gov (United States)

Nevin, Rick; Jacobs, David E; Berg, Michael; Cohen, Jonathan

2008-03-01

Previous estimates of childhood lead poisoning prevention benefits have quantified the present value of some health benefits, but not the costs of lead paint hazard control or the benefits associated with housing and energy markets. Because older housing with lead paint constitutes the main exposure source today in the US, we quantify health benefits, costs, market value benefits, energy savings, and net economic benefits of lead-safe window replacement (which includes paint stabilization and other measures). The benefit per resident child from improved lifetime earnings alone is $21,195 in pre-1940 housing and $8685 in 1940-59 housing (in 2005 dollars). Annual energy savings are $130-486 per housing unit, with or without young resident children, with an associated increase in housing market value of $5900-14,300 per housing unit, depending on home size and number of windows replaced. Net benefits are $4490-5,629 for each housing unit built before 1940, and $491-1629 for each unit built from 1940-1959, depending on home size and number of windows replaced. Lead-safe window replacement in all pre-1960 US housing would yield net benefits of at least $67 billion, which does not include many other benefits. These other benefits, which are shown in this paper, include avoided Attention Deficit Hyperactivity Disorder, other medical costs of childhood lead exposure, avoided special education, and reduced crime and juvenile delinquency in later life. In addition, such a window replacement effort would reduce peak demand for electricity, carbon emissions from power plants, and associated long-term costs of climate change.

Novel gelforming process for near net shape ceramic component production

International Nuclear Information System (INIS)

Franks, G.V.; Johnson, S.B.; Dunstan, D.E.

2000-01-01

A novel gelforming process for producing near-net shape ceramic components has been developed. A low viscosity, high volume fraction, ceramic suspension containing a small amount of bio-polymer is poured or injected into a mould. The suspension is gelled within the mould by a temperature activated crosslinking mechanism. The rheological behaviour of the body within the mould is changed from liquid-like to solid-like in a short period of time. The wet mechanical strength of the gelled bodies is sufficient to allow the body to be demoulded and handled without damaging the component. Near net shapes of complex geometry are formed in this way. The wet green body is then dried and densified using traditional methods. Potentially this process can be used to produce inexpensive reliable high strength ceramic components quickly and safely. Copyright (2000) The Australian Ceramic Society

Initial Results From The Micro-pulse Lidar Network (MPL-Net)

Science.gov (United States)

Welton, E. J.; Campbell, J. R.; Berkoff, T. A.; Spinhirne, J. D.; Ginoux, P.

2001-12-01

The micro-pulse lidar system (MPL) was developed in the early 1990s and was the first small, eye-safe, and autonomous lidar built for fulltime monitoring of cloud and aerosol vertical distributions. In 2000, a new project using MPL systems was started at NASA Goddard Space Flight Center. This new project, the Micro-pulse Lidar Network or MPL-Net, was created to provide long-term observations of aerosol and cloud vertical profiles at key sites around the world. This is accomplished using both NASA operated sites and partnerships with other organizations owning MPL systems. The MPL-Net sites are co-located with NASA AERONET sunphotometers to provide aerosol optical depth data needed for calibration of the MPL. In addition to the long-term sites, MPL-Net provides lidar support for a limited number of field experiments and ocean cruises each year. We will present an overview of the MPL-Net project and show initial results from the first two MPL-Net sites at the South Pole and at Goddard Space Flight Center. Observations of dust layers transported from the desert regions of China, across the Pacific Ocean, to the east coast of the United States will also be shown. MPL-Net affiliated instruments were in place at the desert source region in China, on a research vessel in the Sea of Japan, at ARM sites in Alaska and Oklahoma, and finally at our home site in Maryland (GSFC) during the massive dust storms that occurred in April 2001. The MPL observations of dust layers at each location are shown in comparison to dust layers predicted using the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport model (GOCART). Finally, the MPL-Net project is the primary ground-validation program for the Geo-Science Laser Altimeter System (GLAS) satellite lidar project (launch date 2002). We will present an overview demonstrating how MPL-Net results are used to help prepare the GLAS data processing algorithms and assist in the calibration/validation of the GLAS data

Initial Results from the Micro-pulse Lidar Network (MPL-Net)

Science.gov (United States)

Welton, Ellsworth J.; Campbell, James R.; Berkoff, Timothy A.; Spinhirne, James D.; Ginoux, Paul; Starr, David OC. (Technical Monitor)

2001-01-01

The micro-pulse lidar system (MPL) was developed in the early 1990s and was the first small, eye-safe, and autonomous lidar built for full time monitoring of cloud and aerosol vertical distributions. In 2000, a new project using MPL systems was started at NASA Goddard Space Flight Center. This new project, the Micro-pulse Lidar Network or MPL-Net, was created to provide long-term observations of aerosol and cloud vertical profiles at key sites around the world. This is accomplished using both NASA operated sites and partnerships with other organizations owning MPL systems. The MPL-Net sites are co-located with NASA AERONET sunphotometers to provide aerosol optical depth data needed for calibration of the MPL. In addition to the long-term sites, MPL-Net provides lidar support for a limited number of field experiments and ocean cruises each year. We will present an overview of the MPL-Net project and show initial results from the first two MPL-Net sites at the South Pole and at Goddard Space Flight Center. Observations of dust layers transported from the Gobi desert, across the Pacific Ocean, to the east coast of the United States will also be shown. MPL-Net affiliated instruments were in place at the desert source region in China, on a research vessel in the Sea of Japan, at ARM sites in Alaska and Oklahoma, and finally at our home site in Maryland (GSFC) during the massive dust storms that occurred in April 2001. The MPL observations of dust layers at each location are shown in comparison to dust layers predicted using the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport model (GOCART). Finally, the MPL-Net project is the primary ground-validation program for the Geo-Science Laser Altimeter System (GLAS) satellite lidar project (launch date 2002). We will present an overview demonstrating how MPL-Net results are used to help prepare the GLAS data processing algorithms and assist in the calibration/validation of the GLAS data products.

Modelling an Interactive Road Signs System, Using Petri Nets

Directory of Open Access Journals (Sweden)

Kombe Timothee

2017-03-01

Full Text Available This paper is a contribution to the problems of road insecurity in Africa. Due to non-respect of road sign and to the lack of signing, roads have become places of all dangers. It becomes imperative to establish an interaction between the authorities and the offending drivers. To reach this goal, we modelled an interactive road-vehicle-signage system, who locally informs the driver on the requirements of traffic signs. This model having interest only in the event of driving by bad weather or deterioration of panels, we are amending by inserting functions aimed to warn and punish the driver in the event of maintenance of an offense. Indeed, when the driver is about to commit a fault, firstly the system issues a warming (visual, audible or mechanical. Then, a message (SMS is sent to the authorities. We include the concept of floating process engaged by devices other than the signage. We show that, with a few considerations, from the functional point of view, they are identical to the process engaged by the signage. Furthermore, in terms of performance, the model renewed warnings that occurred just before the end panel of prohibitions. It stores messages of offenses occurred without the network, then notifies them when a network is detected. We propose algorithms for incremental design and analysis of the model, whose processes are activated and / or are extinguished, according to the type of sign or tag encountered. We show by simulation and by linear algebra that, the model retains its properties of absence of blocking and boundedness during the evolution of the system, hence its validation.

Decomposing Petri nets for process mining : a generic approach

NARCIS (Netherlands)

Aalst, van der W.M.P.

2012-01-01

The practical relevance of process mining is increasing as more and more event data become available. Process mining techniques aim to discover, monitor and improve real processes by extracting knowledge from event logs. The two most prominent process mining tasks are: (i) process discovery:

Analysis of hybrid Petri nets with random discrete events

NARCIS (Netherlands)

Ghasemieh, Hamed

2017-01-01

More and more, our society and economy rely on the correct operation of, often hidden, critical infrastructures. These infrastructures such as the power grid and water and gas distribution networks, play an important role in our everyday life. Continuous supply of services from these assets is

Net technique for intraocular lens support in aphakia without capsular support.

Science.gov (United States)

De Novelli, Fernando José; Neto, Theodomiro Lourenço Garrido; de Sena Rabelo, Gabriel; Blumer, Marcel Eduardo; Suzuki, Ricardo; Ghanem, Ramon Coral

2017-01-01

This paper describes a modified surgical technique for intraocular lens implantation in aphakic eyes with no capsular support. Retrospective case series. Seventeen eyes of 17 aphakic patients with no capsule support underwent intraocular lens (IOL) implantation using a standardized technique in which a net was created at the ciliary sulcus plane with two threads forming a net pattern. The net was used as support for the IOL. Follow-up ranged from 6 to 38 months, with an average of 23 months. In all cases, the IOL was safely implanted and remained stable during the follow-up. In 16 eyes, the IOL remained well centered; in one eye, slight decentration was observed. Distance-corrected visual acuity improved by a mean of 4 lines, from 1.13 (LogMAR) to 0.52 (P = 0.01). This technique might be especially useful in cases of insufficient capsular support associated with tissue loss or iris atrophy. In these cases, iris fixation is not feasible; thus, the only surgical alternative is IOL scleral fixation.

Research and realization of info-net security controlling system

Science.gov (United States)

Xu, Tao; Zhang, Wei; Li, Xuhong; Wang, Xia; Pan, Wenwen

2017-03-01

The thesis introduces some relative concepts about Network Cybernetics, and we design and realize a new info-net security controlling system based on Network Cybernetics. The system can control the endpoints, safely save files, encrypt communication, supervise actions of users and show security conditions, in order to realize full-scale security management. At last, we simulate the functions of the system. The results show, the system can ensure the controllability of users and devices, and supervise them real-time. The system can maximize the security of the network and users.

Modeling and simulation of blood collection systems.

Science.gov (United States)

Alfonso, Edgar; Xie, Xiaolan; Augusto, Vincent; Garraud, Olivier

2012-03-01

This paper addresses the modeling and simulation of blood collection systems in France for both fixed site and mobile blood collection with walk in whole blood donors and scheduled plasma and platelet donors. Petri net models are first proposed to precisely describe different blood collection processes, donor behaviors, their material/human resource requirements and relevant regulations. Petri net models are then enriched with quantitative modeling of donor arrivals, donor behaviors, activity times and resource capacity. Relevant performance indicators are defined. The resulting simulation models can be straightforwardly implemented with any simulation language. Numerical experiments are performed to show how the simulation models can be used to select, for different walk in donor arrival patterns, appropriate human resource planning and donor appointment strategies.

The potential of centrifugal casting for the production of near net shape uranium parts

International Nuclear Information System (INIS)

Robertson, E.

1993-09-01

This report was written to provide a detailed summary of a literature survey on the near net shape casting process of centrifugal casting. Centrifugal casting is one potential casting method which could satisfy the requirements of the LANL program titled Near Net Shape Casting of Uranium for Reduced Environmental, Safety and Health Impact. In this report, centrifugal casting techniques are reviewed and an assessment of the ability to achieve the near net shape and waste minimization goals of the LANL program by using these techniques is made. Based upon the literature reviewed, it is concluded that if properly modified for operation within a vacuum, vertical or horizontal centrifugation could be used to safely cast uranium for the production of hollow, cylindrical parts. However, for the production of components of geometries other than hollow tubes, vertical centrifugation could be combined with other casting methods such as semi-permanent mold or investment casting

Safe sex

Science.gov (United States)

... sex; Sexually transmitted - safe sex; GC - safe sex; Gonorrhea - safe sex; Herpes - safe sex; HIV - safe sex; ... contact. STIs include: Chlamydia Genital herpes Genital warts Gonorrhea Hepatitis HIV HPV Syphilis STIs are also called ...

Monetary benefits of preventing childhood lead poisoning with lead-safe window replacement

OpenAIRE

Nevin, Rick; Jacobs, David / E.; Berg, Michael; Cohen, Jonathan

2007-01-01

Previous estimates of childhood lead poisoning prevention benefits have quantified the present value of some health benefits, but not the costs of lead paint hazard control or the benefits associated with housing and energy markets. Because older housing with lead paint constitutes the main exposure source today in the U.S., we quantify health benefits, costs, market value benefits, energy savings, and net economic benefits of lead-safe window replacement (which includes paint stabilization ...

Net one, net two: the primary care network income statement.

Science.gov (United States)

Halley, M D; Little, A W

1999-10-01

Although hospital-owned primary care practices have been unprofitable for most hospitals, some hospitals are achieving competitive advantage and sustainable practice operations. A key to the success of some has been a net income reporting tool that separates practice operating expenses from the costs of creating and operating a network of practices to help healthcare organization managers, physicians, and staff to identify opportunities to improve the network's financial performance. This "Net One, Net Two" reporting allows operations leadership to be held accountable for Net One expenses and strategic leadership to be held accountable for Net Two expenses.

MetNet - In situ observational Network and Orbital platform to investigate the Martian environment

Science.gov (United States)

Harri, Ari-Matti; Leinonen, Jussi; Merikallio, Sini; Paton, Mark; Haukka, Harri; Polkko, Jouni

2007-09-01

MetNet Mars Mission is an in situ observational network and orbital platform mission to investigate the Martian environment and it has been proposed to European Space Agency in response to Call for proposals for the first planning cycle of Cosmic Vision 2015-2025 D/SCI/DJS/SV/val/21851. The MetNet Mars Mission is to be implemented in collaboration with ESA, FMI, LA, IKI and the payload providing science teams. The scope of the MetNet Mission is to deploy 16 MetNet Landers (MNLs) on the Martian surface by using inflatable descent system structures accompanied by an atmospheric sounder and data relay onboard the MetNet Orbiter (MNO), which is based on ESA Mars Express satellite platform. The MNLs are attached on the three sides of the satellite and most of the MNLs are deployed to Mars separately a few weeks prior to the arrival to Mars. The MetNet Orbiter will perform continuous atmospheric soundings thus complementing the accurate in situ observations at the Martian ground produced by the MetNet observation network, as well as the orbiter will serve as the primary data relay between the MetNet Landers and the Earth. The MNLs are equipped with a versatile science payload focused on the atmospheric science of Mars. Detailed characterisation of the Martian atmospheric circulation patterns, boundary layer phenomena, and climatological cycles, as well as interior investigations, require simultaneous in situ meteorological, seismic and magnetic measurements from networks of stations on the Martian surface. MetNet Mars Mission will also provide a crucial support for the safety of large landing missions in general and manned Mars missions in particular. Accurate knowledge of atmospheric conditions and weather data is essential to guarantee safe landings of the forthcoming Mars mission elements.

Application of deconvolution interferometry with both Hi-net and KiK-net data

Science.gov (United States)

Nakata, N.

2013-12-01

Application of deconvolution interferometry to wavefields observed by KiK-net, a strong-motion recording network in Japan, is useful for estimating wave velocities and S-wave splitting in the near surface. Using this technique, for example, Nakata and Snieder (2011, 2012) found changed in velocities caused by Tohoku-Oki earthquake in Japan. At the location of the borehole accelerometer of each KiK-net station, a velocity sensor is also installed as a part of a high-sensitivity seismograph network (Hi-net). I present a technique that uses both Hi-net and KiK-net records for computing deconvolution interferometry. The deconvolved waveform obtained from the combination of Hi-net and KiK-net data is similar to the waveform computed from KiK-net data only, which indicates that one can use Hi-net wavefields for deconvolution interferometry. Because Hi-net records have a high signal-to-noise ratio (S/N) and high dynamic resolution, the S/N and the quality of amplitude and phase of deconvolved waveforms can be improved with Hi-net data. These advantages are especially important for short-time moving-window seismic interferometry and deconvolution interferometry using later coda waves.

Net Neutrality

DEFF Research Database (Denmark)

Savin, Andrej

2017-01-01

Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else.......Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else....

NetSig

DEFF Research Database (Denmark)

Horn, Heiko; Lawrence, Michael S; Chouinard, Candace R

2018-01-01

Methods that integrate molecular network information and tumor genome data could complement gene-based statistical tests to identify likely new cancer genes; but such approaches are challenging to validate at scale, and their predictive value remains unclear. We developed a robust statistic (Net......Sig) that integrates protein interaction networks with data from 4,742 tumor exomes. NetSig can accurately classify known driver genes in 60% of tested tumor types and predicts 62 new driver candidates. Using a quantitative experimental framework to determine in vivo tumorigenic potential in mice, we found that Net......Sig candidates induce tumors at rates that are comparable to those of known oncogenes and are ten-fold higher than those of random genes. By reanalyzing nine tumor-inducing NetSig candidates in 242 patients with oncogene-negative lung adenocarcinomas, we find that two (AKT2 and TFDP2) are significantly amplified...

An Introduction to the Practical Use of Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1998-01-01

— including seventy-five commercial companies. It is available free of charge, also for commercial use. The present paper does not contain any formal definitions. Instead all ideas and concepts are introduced by means of a number of small examples. Readers who want to consult the formal definitions can find...

Stochastic Petri Net Modeling of Wave Sequences in Cardiac Arrhythmias.

Science.gov (United States)

1987-11-01

Wolff - Parkinson - White syndrome . The ventricles are divided into two parts. One of these is excited normally and produces R...example, in a condition called the Wolff - Parkinson - White syn- drome the ECG displays an abnormally early onset of the ventricular activity. It also...8217. , ’ ", -’ , .’ %,,? .’ ,; ’ .- ’ ’ -’ € ’ , . ’ - I. 32 Wolfe- Parkinson - White Syndrome (Fig. 8c) This model uses "basic" elements for the

Electronic Business Transaction Infrastructure Analysis Using Petri Nets and Simulation

Science.gov (United States)

Feller, Andrew Lee

2010-01-01

Rapid growth in eBusiness has made industry and commerce increasingly dependent on the hardware and software infrastructure that enables high-volume transaction processing across the Internet. Large transaction volumes at major industrial-firm data centers rely on robust transaction protocols and adequately provisioned hardware capacity to ensure…

Estimation of parameters of MRSA-05, based on Petri nets

Directory of Open Access Journals (Sweden)

О.І. Варченко

2009-02-01

Full Text Available  Principles of construction and work of the systems of relay defense are considered, developed algorithm of work for block of defense on maximal voltage of microprocessor defense, automation, control and management of connections of 6-35 kV build. The imitation model of device operation is offered.

Learning Visual Basic NET

CERN Document Server

Liberty, Jesse

2009-01-01

Learning Visual Basic .NET is a complete introduction to VB.NET and object-oriented programming. By using hundreds of examples, this book demonstrates how to develop various kinds of applications--including those that work with databases--and web services. Learning Visual Basic .NET will help you build a solid foundation in .NET.

Automatic Evaluation of Colonies Growth rate of Yeasts incubated in Petri dishes using Mobile Platform

Directory of Open Access Journals (Sweden)

Alecsander Pereira Martins

2015-10-01

Full Text Available This paper proposes an automatic method based on computer vision implemented in mobile platform capable of monitoring the growth of microbial colonies incubated in Petri dishes. The developed optimized image processing algorithm performs this task without human intervention from images of colonies of the microorganism in different evolution phases. The contribution of this paper is the development of a fast and robust mobile tool to assist bioprocess experts in monitoring the growth of colonies without using the conventional error prone evaluation techniques. The obtained results successfully demonstrated dimensional alterations in colonies in a faster and more precise fashion when compared with the conventional method, with the additional advantage of versatility in producing reliable estimation of the growth rates with higher statistical significance.

The NetQuakes Project - Seeking a Balance Between Science and Citizens.

Science.gov (United States)

Luetgert, J. H.; Oppenheimer, D. H.

2012-12-01

The challenge for any system that uses volunteer help to do science is to dependably acquire quality data without unduly burdening the volunteer. The NetQuakes accelerograph and its data acquisition system were created to address the recognized need for more densely sampled strong ground motion recordings in urban areas to provide more accurate ShakeMaps for post-earthquake disaster assessment and to provide data for structural engineers to improve design standards. The recorder has 18 bit resolution with ±3g internal tri-axial MEMS accelerometers. Data are continuously recorded at 200 sps into a 1-2 week ringbuffer. When triggered, a miniSEED file is sent to USGS servers via the Internet. Data can also be recovered from the ringbuffer by a remote request through the NetQuakes servers. Following a power failure, the instrument can run for 36 hours using its internal battery. We rely upon cooperative citizens to host the dataloggers, provide power and Internet connectivity and perform minor servicing. Instrument and battery replacement are simple tasks that can be performed by hosts, thus reducing maintenance costs. Communication with the instrument to acquire data or deliver firmware is accomplished by file transfers using NetQuakes servers. The client instrument initiates all client-server interactions, so it safely resides behind a host's firewall. A connection to the host's LAN, and from there to the public Internet, can be made using WiFi to minimize cabling. Although timing using a cable to an external GPS antenna is possible, it is simpler to use the Network Time Protocol (NTP) to discipline the internal clock. This approach achieves timing accuracy substantially better than a sample interval. Since 2009, we have installed more than 140 NetQuakes instruments in the San Francisco Bay Area and have successfully integrated their data into the near real time data stream of the Northern California Seismic System. An additional 235 NetQuakes instruments have been

Pro-Nets versus No-Nets: Differences in Urban Older Adults' Predilections for Internet Use

Science.gov (United States)

Cresci, M. Kay; Yarandi, Hossein N.; Morrell, Roger W.

2010-01-01

Enthusiasm for information technology (IT) is growing among older adults. Many older adults enjoy IT and the Internet (Pro-Nets), but others have no desire to use it (No-Nets). This study found that Pro-Nets and No-Nets were different on a number of variables that might predict IT use. No-Nets were older, had less education and income, were…

Experiments and simulation of a net closing mechanism for tether-net capture of space debris

Science.gov (United States)

Sharf, Inna; Thomsen, Benjamin; Botta, Eleonora M.; Misra, Arun K.

2017-10-01

This research addresses the design and testing of a debris containment system for use in a tether-net approach to space debris removal. The tether-net active debris removal involves the ejection of a net from a spacecraft by applying impulses to masses on the net, subsequent expansion of the net, the envelopment and capture of the debris target, and the de-orbiting of the debris via a tether to the chaser spacecraft. To ensure a debris removal mission's success, it is important that the debris be successfully captured and then, secured within the net. To this end, we present a concept for a net closing mechanism, which we believe will permit consistently successful debris capture via a simple and unobtrusive design. This net closing system functions by extending the main tether connecting the chaser spacecraft and the net vertex to the perimeter and around the perimeter of the net, allowing the tether to actuate closure of the net in a manner similar to a cinch cord. A particular embodiment of the design in a laboratory test-bed is described: the test-bed itself is comprised of a scaled-down tether-net, a supporting frame and a mock-up debris. Experiments conducted with the facility demonstrate the practicality of the net closing system. A model of the net closure concept has been integrated into the previously developed dynamics simulator of the chaser/tether-net/debris system. Simulations under tether tensioning conditions demonstrate the effectiveness of the closure concept for debris containment, in the gravity-free environment of space, for a realistic debris target. The on-ground experimental test-bed is also used to showcase its utility for validating the dynamics simulation of the net deployment, and a full-scale automated setup would make possible a range of validation studies of other aspects of a tether-net debris capture mission.

Simulación de un sistema de manufactura flexible con redes de Petri coloreadas

Directory of Open Access Journals (Sweden)

Luis Diego Murillo Soto

2010-10-01

Full Text Available Una forma de estudiar un sistema de manufactura flexible es por medio de un modelo del sistema y someterlo a un simulacro para observar sus índices de comportamiento, gráficas, etc. Siguiendo esta pauta, el presente trabajo plantea la simulación de una línea de producción con tres máquinas, dos robots y tres tipos de productos distintos. Con dicho sistema se desea obtener, en forma automática, porcentajes del uso de las máquinas, tamaño promedio de las colas, gráficas del comportamiento de las colas y el diagrama Gantt. El modelado de la línea de producción se realizó con Redes de Petri Coloreadas (RdPC y su implementación se realizó con la herramienta CPNTool.

76 FR 12719 - Safe Schools/Healthy Students Program; Office of Safe and Drug-Free Schools; Safe Schools/Healthy...

Science.gov (United States)

2011-03-08

... DEPARTMENT OF EDUCATION Safe Schools/Healthy Students Program; Office of Safe and Drug- Free Schools; Safe Schools/Healthy Students Program; Catalog of Federal Domestic Assistance (CFDA) Numbers: 84... priorities, requirements, and definitions under the Safe Schools/Healthy Students (SS/HS) program. Since...

ROOT.NET: Using ROOT from .NET languages like C# and F#

Science.gov (United States)

Watts, G.

2012-12-01

ROOT.NET provides an interface between Microsoft's Common Language Runtime (CLR) and .NET technology and the ubiquitous particle physics analysis tool, ROOT. ROOT.NET automatically generates a series of efficient wrappers around the ROOT API. Unlike pyROOT, these wrappers are statically typed and so are highly efficient as compared to the Python wrappers. The connection to .NET means that one gains access to the full series of languages developed for the CLR including functional languages like F# (based on OCaml). Many features that make ROOT objects work well in the .NET world are added (properties, IEnumerable interface, LINQ compatibility, etc.). Dynamic languages based on the CLR can be used as well, of course (Python, for example). Additionally it is now possible to access ROOT objects that are unknown to the translation tool. This poster will describe the techniques used to effect this translation, along with performance comparisons, and examples. All described source code is posted on the open source site CodePlex.

ROOT.NET: Using ROOT from .NET languages like C and F

International Nuclear Information System (INIS)

Watts, G

2012-01-01

ROOT.NET provides an interface between Microsoft's Common Language Runtime (CLR) and .NET technology and the ubiquitous particle physics analysis tool, ROOT. ROOT.NET automatically generates a series of efficient wrappers around the ROOT API. Unlike pyROOT, these wrappers are statically typed and so are highly efficient as compared to the Python wrappers. The connection to .NET means that one gains access to the full series of languages developed for the CLR including functional languages like F (based on OCaml). Many features that make ROOT objects work well in the .NET world are added (properties, IEnumerable interface, LINQ compatibility, etc.). Dynamic languages based on the CLR can be used as well, of course (Python, for example). Additionally it is now possible to access ROOT objects that are unknown to the translation tool. This poster will describe the techniques used to effect this translation, along with performance comparisons, and examples. All described source code is posted on the open source site CodePlex.

On Probabilistic Automata in Continuous Time

DEFF Research Database (Denmark)

Eisentraut, Christian; Hermanns, Holger; Zhang, Lijun

2010-01-01

We develop a compositional behavioural model that integrates a variation of probabilistic automata into a conservative extension of interactive Markov chains. The model is rich enough to embody the semantics of generalised stochastic Petri nets. We define strong and weak bisimulations and discuss...

Survivability of SCADA Control Loop

NARCIS (Netherlands)

Camacho, José; de Boer, Pieter-Tjerk; Remke, Anne Katharina Ingrid

2009-01-01

The endorsement of information technologies for critical infrastructures control introduces new threats in their security and surveillance. Along with certain level of protection against attacks, it is desirable for critical processes to survive even if they succeed. A stochastic Petri Nets-based

Application of Executable Architectures in Early Concept Evaluation

Science.gov (United States)

2015-12-01

immature or deficient in this feature and/or provide little attention to the creation of an integrated executable architecture solution. Innoslate... Coloured Petri Nets and CPN Tools for modelling and validation of concurrent systems. International Journal on Software Tools for Technology Transfer

Polynomial algebra of discrete models in systems biology.

Science.gov (United States)

Veliz-Cuba, Alan; Jarrah, Abdul Salam; Laubenbacher, Reinhard

2010-07-01

An increasing number of discrete mathematical models are being published in Systems Biology, ranging from Boolean network models to logical models and Petri nets. They are used to model a variety of biochemical networks, such as metabolic networks, gene regulatory networks and signal transduction networks. There is increasing evidence that such models can capture key dynamic features of biological networks and can be used successfully for hypothesis generation. This article provides a unified framework that can aid the mathematical analysis of Boolean network models, logical models and Petri nets. They can be represented as polynomial dynamical systems, which allows the use of a variety of mathematical tools from computer algebra for their analysis. Algorithms are presented for the translation into polynomial dynamical systems. Examples are given of how polynomial algebra can be used for the model analysis. alanavc@vt.edu Supplementary data are available at Bioinformatics online.

Formal Modeling and Verification for MVB

Directory of Open Access Journals (Sweden)

Mo Xia

2013-01-01

Full Text Available Multifunction Vehicle Bus (MVB is a critical component in the Train Communication Network (TCN, which is widely used in most of the modern train techniques of the transportation system. How to ensure security of MVB has become an important issue. Traditional testing could not ensure the system correctness. The MVB system modeling and verification are concerned in this paper. Petri Net and model checking methods are used to verify the MVB system. A Hierarchy Colored Petri Net (HCPN approach is presented to model and simulate the Master Transfer protocol of MVB. Synchronous and asynchronous methods are proposed to describe the entities and communication environment. Automata model of the Master Transfer protocol is designed. Based on our model checking platform M3C, the Master Transfer protocol of the MVB is verified and some system logic critical errors are found. Experimental results show the efficiency of our methods.

Nested Interrupt Analysis of Low Cost and High Performance Embedded Systems Using GSPN Framework

Science.gov (United States)

Lin, Cheng-Min

Interrupt service routines are a key technology for embedded systems. In this paper, we introduce the standard approach for using Generalized Stochastic Petri Nets (GSPNs) as a high-level model for generating CTMC Continuous-Time Markov Chains (CTMCs) and then use Markov Reward Models (MRMs) to compute the performance for embedded systems. This framework is employed to analyze two embedded controllers with low cost and high performance, ARM7 and Cortex-M3. Cortex-M3 is designed with a tail-chaining mechanism to improve the performance of ARM7 when a nested interrupt occurs on an embedded controller. The Platform Independent Petri net Editor 2 (PIPE2) tool is used to model and evaluate the controllers in terms of power consumption and interrupt overhead performance. Using numerical results, in spite of the power consumption or interrupt overhead, Cortex-M3 performs better than ARM7.

Testability of numerical systems

International Nuclear Information System (INIS)

Soulas, B.

1992-01-01

In order to face up to the growing complexity of systems, the authors undertook to define a new approach for the qualification of systems. This approach is based on the concept of Testability which, supported by system modelization, validation and verification methods and tools, would allow Integrated Qualification process, applied throughout the life-span of systems. The general principles of this approach are introduced in the general case of numerical systems; in particular, this presentation points out the difference between the specification activity and the modelization and validation activity. This approach is illustrated firstly by the study of a global system and then by case of communication protocol as the software point of view. Finally MODEL which support this approach is described. MODEL tool is a commercial tool providing modelization and validation techniques based on Petri Nets with triple extension: Predicate/Transition, Timed and Stochastic Petri Nets

INMARSAT-C SafetyNET

Science.gov (United States)

Tsunamis 406 EPIRB's National Weather Service Marine Forecasts INMARSAT-C SafetyNET Marine Forecast Offices greater danger near shore or any shallow waters? NATIONAL WEATHER SERVICE PRODUCTS VIA INMARSAT-C SafetyNET Inmarsat-C SafetyNET is an internationally adopted, automated satellite system for promulgating

Quantum net dynamics

International Nuclear Information System (INIS)

Finkelstein, D.

1989-01-01

The quantum net unifies the basic principles of quantum theory and relativity in a quantum spacetime having no ultraviolet infinities, supporting the Dirac equation, and having the usual vacuum as a quantum condensation. A correspondence principle connects nets to Schwinger sources and further unifies the vertical structure of the theory, so that the functions of the many hierarchic levels of quantum field theory (predicate algebra, set theory, topology,hor-ellipsis, quantum dynamics) are served by one in quantum net dynamics

Cool and Safe: Multiplicity in Safe Innovation at Unilever

Science.gov (United States)

Penders, Bart

2011-01-01

This article presents the making of a safe innovation: the application of ice structuring protein (ISP) in edible ices. It argues that safety is not the absence of risk but is an active accomplishment; innovations are not "made safe afterward" but "safe innovations are made". Furthermore, there are multiple safeties to be accomplished in the…

Concurrency meets probability: theory and practice (abstract)

NARCIS (Netherlands)

Katoen, Joost P.

Treating random phenomena in concurrency theory has a long tradition. Petri nets [18, 10] and process algebras [14] have been extended with probabilities. The same applies to behavioural semantics such as strong and weak (bi)simulation [1], and testing pre-orders [5]. Beautiful connections between

Model-Based Analysis of a Windmill Communication System

DEFF Research Database (Denmark)

Tjell, Simon

2006-01-01

This paper presents the experiences obtained from modeling and analyzing a real-world application of distributed embedded computing. The modeling language Coloured Petri Nets (CPN) has been applied to analyze the properties of a communication system in a windmill, which enables a group of embedded...

Planning of nets

International Nuclear Information System (INIS)

Carberry, M

1996-01-01

The paper is about the planning of nets in areas of low density like it is the case of the rural areas. The author includes economic and technological aspects, planning of nets, demands and management among others

Programming NET Web Services

CERN Document Server

Ferrara, Alex

2007-01-01

Web services are poised to become a key technology for a wide range of Internet-enabled applications, spanning everything from straight B2B systems to mobile devices and proprietary in-house software. While there are several tools and platforms that can be used for building web services, developers are finding a powerful tool in Microsoft's .NET Framework and Visual Studio .NET. Designed from scratch to support the development of web services, the .NET Framework simplifies the process--programmers find that tasks that took an hour using the SOAP Toolkit take just minutes. Programming .NET

Function Allocation between Automation and Human Pilot for Airborne Separation Assurance

Science.gov (United States)

Idris, Husni; Enea, Gabriele; Lewis, TImothy A.

2016-01-01

Maintaining safe separation between aircraft is a key determinant of the airspace capacity to handle air transportation. With the advent of satellite-based surveillance, aircraft equipped with the needed technologies are now capable of maintaining awareness of their location in the airspace and sharing it with their surrounding traffic. As a result, concepts and cockpit automation are emerging to enable delegating the responsibility of maintaining safe separation from traffic to the pilot; thus increasing the airspace capacity by alleviating the limitation of the current non-scalable centralized ground-based system. In this paper, an analysis of allocating separation assurance functions to the human pilot and cockpit automation is presented to support the design of these concepts and technologies. A task analysis was conducted with the help of Petri nets to identify the main separation assurance functions and their interactions. Each function was characterized by three behavior levels that may be needed to perform the task: skill, rule and knowledge based levels. Then recommendations are made for allocating each function to an automation scale based on their behavior level characterization and with the help of Subject matter experts.

Turing Incompleteness of Asynchronous P Systems with Active Membranes

OpenAIRE

Leporati, Alberto; Manzoni, Luca; Porreca, Antonio E.

2013-01-01

We prove that asynchronous P systems with active membranes without divi- sion rules can be simulated by place/transition Petri nets, and hence are computationally weaker than Turing machines. This result holds even if the synchronisation mechanisms provided by electrical charges and membrane dissolution are exploited.

Quantitative analysis of resource-constrained business processes

NARCIS (Netherlands)

Oliveira, C.A.L.; Lima, R.M.F.; Reijers, H.A.; Ribeiro, J.T.S.

2012-01-01

To address the need for evaluation techniques for complex business processes, also known as workflows, this paper proposes an approach based on generalized stochastic Petri nets (GSPNs). We review ten related approaches published in the last fifteen years and compare them to our approach using a

Minimality of critical scenarios with linear logic and cutsets

African Journals Online (AJOL)

DK

Keywords: Dependability - Mechatronic systems -Petri net - Linear logic - Minimal Feared scenarios - Cutsets. ..... Energy supply. Detection high level. Relay. ET. Energy supply. Detection high level. Relay ..... Evaluation de la SdF des systèmes mécatroniques en utilisant ... in complex distributed systems, Proceedings of the.

Versatile Markovian models for networks with asymmetric TCP sources

NARCIS (Netherlands)

van Foreest, N.D.; Haverkort, Boudewijn R.H.M.; Mandjes, M.R.H.; Scheinhardt, Willem R.W.

2004-01-01

In this paper we use Stochastic Petri Nets (SPNs) to study the interaction of multiple TCP sources that share one or two buffers, thereby considerably extending earlier work. We first consider two sources sharing a buffer and investigate the consequences of two popular assumptions for the loss

Translating Message Sequence Charts to other Process Languages using Process

DEFF Research Database (Denmark)

Lassen, Kristian Bisgaard; van Dongen, Boudewijn F.

2008-01-01

stakeholders. Often such discussions lead to more complete behavioral models described by e.g. Event-driven Process Chains (EPCs), UML activity diagrams, BPMN models, Petri nets, etc. Process mining on the other hand, deals with the problem of constructing complete behavioral models by analyzing event logs...

Resonance – Journal of Science Education | Indian Academy of ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 8. Petri Nets - Overview and Foundations. Y Narahari. General Article Volume 4 Issue 8 August 1999 pp ... Author Affiliations. Y Narahari1. Department ot Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India.

Repairing process models to reflect reality

NARCIS (Netherlands)

Fahland, D.; Aalst, van der W.M.P.; Barros, A.; Gal, A.; Kindler, E.

2012-01-01

Process mining techniques relate observed behavior (i.e., event logs) to modeled behavior (e.g., a BPMN model or a Petri net). Processes models can be discovered from event logs and conformance checking techniques can be used to detect and diagnose differences between observed and modeled behavior.

Net zero water

CSIR Research Space (South Africa)

Lindeque, M

2013-01-01

Full Text Available the national grid. The unfortunate situation with water is that there is no replacement technology for water. Water can be supplied from many different sources. A net zero energy development will move closer to a net zero water development by reducing...

Towards new information resources for public health--from WordNet to MedicalWordNet.

Science.gov (United States)

Fellbaum, Christiane; Hahn, Udo; Smith, Barry

2006-06-01

In the last two decades, WordNet has evolved as the most comprehensive computational lexicon of general English. In this article, we discuss its potential for supporting the creation of an entirely new kind of information resource for public health, viz. MedicalWordNet. This resource is not to be conceived merely as a lexical extension of the original WordNet to medical terminology; indeed, there is already a considerable degree of overlap between WordNet and the vocabulary of medicine. Instead, we propose a new type of repository, consisting of three large collections of (1) medically relevant word forms, structured along the lines of the existing Princeton WordNet; (2) medically validated propositions, referred to here as medical facts, which will constitute what we shall call MedicalFactNet; and (3) propositions reflecting laypersons' medical beliefs, which will constitute what we shall call the MedicalBeliefNet. We introduce a methodology for setting up the MedicalWordNet. We then turn to the discussion of research challenges that have to be met to build this new type of information resource. We build a database of sentences relevant to the medical domain. The sentences are generated from WordNet via its relations as well as from medical statements broken down into elementary propositions. Two subcorpora of sentences are distinguished, MedicalBeliefNet and MedicalFactNet. The former is rated for assent by laypersons; the latter for correctness by medical experts. The sentence corpora will be valuable for a variety of applications in information retrieval as well as in research in linguistics and psychology with respect to the study of expert and non-expert beliefs and their linguistic expressions. Our work has to meet several considerable challenges. These include accounting for the distinction between medical experts and laypersons, the social issues of expert-layperson communication in different media, the linguistic aspects of encoding medical knowledge, and

Inference-based procedural modeling of solids

KAUST Repository

Biggers, Keith

2011-11-01

As virtual environments become larger and more complex, there is an increasing need for more automated construction algorithms to support the development process. We present an approach for modeling solids by combining prior examples with a simple sketch. Our algorithm uses an inference-based approach to incrementally fit patches together in a consistent fashion to define the boundary of an object. This algorithm samples and extracts surface patches from input models, and develops a Petri net structure that describes the relationship between patches along an imposed parameterization. Then, given a new parameterized line or curve, we use the Petri net to logically fit patches together in a manner consistent with the input model. This allows us to easily construct objects of varying sizes and configurations using arbitrary articulation, repetition, and interchanging of parts. The result of our process is a solid model representation of the constructed object that can be integrated into a simulation-based environment. © 2011 Elsevier Ltd. All rights reserved.

Cell illustrator 4.0: a computational platform for systems biology.

Science.gov (United States)

Nagasaki, Masao; Saito, Ayumu; Jeong, Euna; Li, Chen; Kojima, Kaname; Ikeda, Emi; Miyano, Satoru

2011-01-01

Cell Illustrator is a software platform for Systems Biology that uses the concept of Petri net for modeling and simulating biopathways. It is intended for biological scientists working at bench. The latest version of Cell Illustrator 4.0 uses Java Web Start technology and is enhanced with new capabilities, including: automatic graph grid layout algorithms using ontology information; tools using Cell System Markup Language (CSML) 3.0 and Cell System Ontology 3.0; parameter search module; high-performance simulation module; CSML database management system; conversion from CSML model to programming languages (FORTRAN, C, C++, Java, Python and Perl); import from SBML, CellML, and BioPAX; and, export to SVG and HTML. Cell Illustrator employs an extension of hybrid Petri net in an object-oriented style so that biopathway models can include objects such as DNA sequence, molecular density, 3D localization information, transcription with frame-shift, translation with codon table, as well as biochemical reactions.

Transactions in domain-specific information systems

Science.gov (United States)

Zacek, Jaroslav

2017-07-01

Substantial number of the current information system (IS) implementations is based on transaction approach. In addition, most of the implementations are domain-specific (e.g. accounting IS, resource planning IS). Therefore, we have to have a generic transaction model to build and verify domain-specific IS. The paper proposes a new transaction model for domain-specific ontologies. This model is based on value oriented business process modelling technique. The transaction model is formalized by the Petri Net theory. First part of the paper presents common business processes and analyses related to business process modeling. Second part defines the transactional model delimited by REA enterprise ontology paradigm and introduces states of the generic transaction model. The generic model proposal is defined and visualized by the Petri Net modelling tool. Third part shows application of the generic transaction model. Last part of the paper concludes results and discusses a practical usability of the generic transaction model.

Towards the Development of Effective and Flexible Information Systems

Directory of Open Access Journals (Sweden)

Aphrodite Tsalgatidou

1994-05-01

Full Text Available The development of Information Systems which are effective (i.e. satisfy users' needs and flexible enough to incorporate future changes of user requirements basically depends on the importance given to the requirements analysis stage and to the techniques employed for their development This paper presents a new approach to requirements analysis through an environment called VENUS. The VENUS environment provides a set of tools to support the requirements capture and analysis process so that design and development is more effective and flexible. The construction of user requirements starts by first constructing an Entity-Relationship Model which is then transformed to an Object-oriented Rule-based Model (ORM where rules are used for the definition of the behaviour of each object class. ORM is then mapped to a graphical Petri-net based model and is validated by employing graphical animation and exploiting formal properties of the underlying Petri-net formalism.

Multiflavor string-net models

Science.gov (United States)

Lin, Chien-Hung

2017-05-01

We generalize the string-net construction to multiple flavors of strings, each of which is labeled by the elements of an Abelian group Gi. The same flavor of strings can branch, while different flavors of strings can cross one another and thus they form intersecting string nets. We systematically construct the exactly soluble lattice Hamiltonians and the ground-state wave functions for the intersecting string-net condensed phases. We analyze the braiding statistics of the low-energy quasiparticle excitations and find that our model can realize all the topological phases as the string-net model with group G =∏iGi . In this respect, our construction provides various ways of building lattice models which realize topological order G , corresponding to different partitions of G and thus different flavors of string nets. In fact, our construction concretely demonstrates the Künneth formula by constructing various lattice models with the same topological order. As an example, we construct the G =Z2×Z2×Z2 string-net model which realizes a non-Abelian topological phase by properly intersecting three copies of toric codes.

Rare, but challenging tumors: NET

International Nuclear Information System (INIS)

Ivanova, D.; Balev, B.

2013-01-01

Full text: Introduction: Gastroenteropancreatic Neuroendocrine Tumors (GEP - NET) are a heterogeneous group of tumors with different locations and many different clinical, histological, and imaging performance. In a part of them a secretion of various organic substances is present. The morbidity of GEP - NET in the EU is growing, and this leads to increase the attention to them. What you will learn: Imaging methods used for localization and staging of GEP - NET, characteristics of the study’s protocols; Classification of GEP - NET; Demonstration of typical and atypical imaging features of GEP - NET in patients registered at the NET Center at University Hospital ‘St. Marina’, Varna; Features of metastatic NET, The role of imaging in the evaluation of treatment response and follow-up of the patients. Discussion: The image semiotics analysis is based on 19 cases of GEP - NET registered NET Center at University Hospital ‘St. Marina’. The main imaging method is multidetector CT (MDCT), and magnetic resonance imaging (MRI ) has advantages in the evaluation of liver lesions and the local prevalence of anorectal tumors. In patients with advanced disease and liver lesions the assessment of skeletal involvement (MRI/ nuclear medical method) is mandatory. The majority of GEP - NET have not any specific imaging findings. Therefore it is extremely important proper planning and conducting of the study (MDCT and MR enterography; accurate assessment phase of scanning, positive and negative contrast). Conclusion: GEP - NET is a major diagnostic challenge due to the absence of typical imaging characteristics and often an overlap with those of the tumors of different origin can be observed. Therefore, a good knowledge of clinical and imaging changes occurring at different locations is needed. MDCT is the basis for the diagnosis, staging and follow-up of these neoplasms

Limitations of shallow nets approximation.

Science.gov (United States)

Lin, Shao-Bo

2017-10-01

In this paper, we aim at analyzing the approximation abilities of shallow networks in reproducing kernel Hilbert spaces (RKHSs). We prove that there is a probability measure such that the achievable lower bound for approximating by shallow nets can be realized for all functions in balls of reproducing kernel Hilbert space with high probability, which is different with the classical minimax approximation error estimates. This result together with the existing approximation results for deep nets shows the limitations for shallow nets and provides a theoretical explanation on why deep nets perform better than shallow nets. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of netting solidity ratio and inclined angle on the hydrodynamic characteristics of knotless polyethylene netting

Science.gov (United States)

Tang, Hao; Hu, Fuxiang; Xu, Liuxiong; Dong, Shuchuang; Zhou, Cheng; Wang, Xuefang

2017-10-01

Knotless polyethylene (PE) netting has been widely used in aquaculture cages and fishing gears, especially in Japan. In this study, the hydrodynamic coefficient of six knotless PE netting panels with different solidity ratios were assessed in a flume tank under various attack angles of netting from 0° (parallel to flow) to 90° (perpendicular to flow) and current speeds from 40 cm s-1 to 130 cm s-1. It was found that the drag coefficient was related to Reynolds number, solidity ratio and attack angle of netting. The solidity ratio was positively related with drag coefficient for netting panel perpendicular to flow, whereas when setting the netting panel parallel to the flow the opposite result was obtained. For netting panels placed at an angle to the flow, the lift coefficient reached the maximum at an attack angle of 50° and then decreased as the attack angle further increased. The solidity ratio had a dual influence on drag coefficient of inclined netting panels. Compared to result in the literature, the normal drag coefficient of knotless PE netting measured in this study is larger than that of nylon netting or Dyneema netting.

Use of bed nets and factors that influence bed net use among Jinuo Ethnic Minority in southern China.

Science.gov (United States)

Xu, Jian-wei; Liao, Yuan-mei; Liu, Hui; Nie, Ren-hua; Havumaki, Joshua

2014-01-01

Insecticide-treated nets (ITNs) are an integral part of vector control recommendations for malaria elimination in China. This study investigated the extent to which bed nets were used and which factors influence bed net use among Jinuo Ethnic Minority in China-Myanmar-Laos border areas. This study combined a quantitative household questionnaire survey and qualitative semi-structured in-depth interviews (SDI). Questionnaires were administered to 352 heads of households. SDIs were given to 20 key informants. The bed net to person ratio was 1∶2.1 (i.e., nearly one net for every two people), however only 169 (48.0%) households owned at least one net and 623 (47.2%) residents slept under bed nets the prior night. The percentages of residents who regularly slept under nets (RSUN) and slept under nets the prior night (SUNPN) were similar (48.0% vs. 47.2%, P>0.05), however the percentage correct use of nets (CUN) was significantly lower (34.5%, Pcash income per person (ACIP) was an independent factor that influenced bed net use (PHigh bed net availability does not necessarily mean higher coverage or bed net use. Household income, house type and knowledge of the ability of bed nets to prevent malaria are all independent factors that influence bed net use among Jinuo Ethnic Minority.

Fusion through the NET

International Nuclear Information System (INIS)

Spears, B.

1987-01-01

The paper concerns the next generation of fusion machines which are intended to demonstrate the technical viability of fusion. In Europe, the device that will follow on from JET is known as NET - the Next European Torus. If the design programme for NET proceeds, Europe could start to build the machine in 1994. The present JET programme hopes to achieve breakeven in the early 1990's. NET hopes to reach ignition in the next century, and so lay the foundation for a demonstration reactor. A description is given of the technical specifications of the components of NET, including: the first wall, the divertors to protect the wall, the array of magnets that provide the fields containing the plasma, the superconducting magnets, and the shield of the machine. NET's research programme is briefly outlined, including the testing programme to optimise conditions in the machine to achieve ignition, and its safety work. (U.K.)

NetView technical research

Science.gov (United States)

1993-01-01

This is the Final Technical Report for the NetView Technical Research task. This report is prepared in accordance with Contract Data Requirements List (CDRL) item A002. NetView assistance was provided and details are presented under the following headings: NetView Management Systems (NMS) project tasks; WBAFB IBM 3090; WPAFB AMDAHL; WPAFB IBM 3084; Hill AFB; McClellan AFB AMDAHL; McClellan AFB IBM 3090; and Warner-Robins AFB.

The SafeCOP ECSEL Project: Safe Cooperating Cyber-Physical Systems Using Wireless Communication

DEFF Research Database (Denmark)

Pop, Paul; Scholle, Detlef; Hansson, Hans

2016-01-01

This paper presents an overview of the ECSEL project entitled "Safe Cooperating Cyber-Physical Systems using Wireless Communication" (SafeCOP), which runs during the period 2016 -- 2019. SafeCOP targets safety-related Cooperating Cyber-Physical Systems (CO-CPS) characterised by use of wireless...... detection of abnormal behaviour, triggering if needed a safe degraded mode. SafeCOP will also develop methods and tools, which will be used to produce safety assurance evidence needed to certify cooperative functions. SafeCOP will extend current wireless technologies to ensure safe and secure cooperation...

Efficacy of PermaNet® 3.0 and PermaNet® 2.0 nets against laboratory-reared and wild Anopheles gambiae sensu lato populations in northern Tanzania.

Science.gov (United States)

Kweka, Eliningaya J; Lyaruu, Lucile J; Mahande, Aneth M

2017-01-18

Mosquitoes have developed resistance against pyrethroids, the only class of insecticides approved for use on long-lasting insecticidal nets (LLINs). The present study sought to evaluate the efficacy of the pyrethroid synergist PermaNet® 3.0 LLIN versus the pyrethroid-only PermaNet® 2.0 LLIN, in an East African hut design in Lower Moshi, northern Tanzania. In this setting, resistance to pyrethroid insecticides has been identified in Anopheles gambiae mosquitoes. Standard World Health Organization bioefficacy evaluations were conducted in both laboratory and experimental huts. Experimental hut evaluations were conducted in an area where there was presence of a population of highly pyrethroid-resistant An. arabiensis mosquitoes. All nets used were subjected to cone bioassays and then to experimental hut trials. Mosquito mortality, blood-feeding inhibition and personal protection rate were compared between untreated nets, unwashed LLINs and LLINs that were washed 20 times. Both washed and unwashed PermaNet® 2.0 and PermaNet® 3.0 LLINs had knockdown and mortality rates of 100% against a susceptible strain of An. gambiae sensu stricto. The adjusted mortality rate of the wild mosquito population after use of the unwashed PermaNet® 3.0 and PermaNet® 2.0 nets was found to be higher than after use of the washed PermaNet® 2.0 and PermaNet® 3.0 nets. Given the increasing incidence of pyrethroid resistance in An. gambiae mosquitoes in Tanzania, we recommend that consideration is given to its distribution in areas with pyrethroid-resistant malaria vectors within the framework of a national insecticide-resistance management plan.

PODATKOVNE STORITVE ADO.NET IN ADO.NET ENTITY FRAMEWORK

OpenAIRE

Volavc, Franc

2012-01-01

V diplomskem delu smo predstavili Microsoftovi ogrodji ADO.NET in ADO.NET Entity Framework. Preučili in analizirali smo metode za dostop do podatkovnih virov, ki jih ponujata ogrodji, ter nato te ugotovitve preslikati v odločitveno drevo, katero bo programerjem in razvijalcem informacijskih sistemov pomagalo pri odločanju glede pristopa za dostop do podatkovnih virov. Ker bomo v diplomskem delu predstavili Microsoftovi ogrodji, bomo posledično omejeni zgolj na Microsoftovo tehnologijo, se pra...

Blanket testing in NET

International Nuclear Information System (INIS)

Chazalon, M.; Daenner, W.; Libin, B.

1989-01-01

The testing stages in NET for the performance assessment of the various breeding blanket concepts developed at the present time in Europe for DEMO (LiPb and ceramic blankets) and the requirements upon NET to perform these tests are reviewed. Typical locations available in NET for blanket testing are the central outboard segments and the horizontal ports of in-vessel sectors. These test positions will be connectable with external test loops. The number of test loops (helium, water, liquid metal) will be such that each major class of blankets can be tested in NET. The test positions, the boundary conditions and the external test loops are identified and the requirements for test blankets are summarized (author). 6

MODELLING AND VERIFICATION OF KITSAT PACKET COMMUNICATION PROTOCOLS

Directory of Open Access Journals (Sweden)

Young-Ro Lee

1996-06-01

Full Text Available In this paper, in order to verify KITSAT 1/2 packet communication protocols, we model the AX.25 protocol and PACSAT protocol by using an extended Petri net and then verify the correctness, boundedness, liveness and deadlock freeness of packet protocols by utilizing reachability trees.

What makes a good process model? Lessons learned from process mining

NARCIS (Netherlands)

Aalst, van der W.M.P.

2012-01-01

There seems to be a never ending stream of new process modeling notations. Some of these notations are foundational and have been around for decades (e.g., Petri nets). Other notations are vendor specific, incremental, or are only popular for a short while. Discussions on the various competing

Translating Message Sequence Charts to other Process Languages using Process Mining

DEFF Research Database (Denmark)

Lassen, Kristian Bisgaard; van Dongen, Boudewijn; van der Aalst, Wil M. P.

stakeholders. Often such discussions lead to more complete behavioral models described by e.g.\\ Event-driven Process Chains (EPCs), UML activity diagrams, BPMN models, Petri nets, etc. The contribution of this paper is to present a method that uses process mining to translate a set of MSCs that represent...

Interval Abstraction Refinement for Model Checking of Timed-Arc Petri Nets

DEFF Research Database (Denmark)

Viesmose, Sine Lyhne; Jacobsen, Thomas Stig; Jensen, Jacob Jon

2014-01-01

can be considerably faster but it does not in general guarantee conclusive answers. We implement the algorithms within the open-source model checker TAPAAL and demonstrate on a number of experiments that our approximation techniques often result in a significant speed-up of the verification....

Verification of Timed Healthcare Workflows Using Component Timed-Arc Petri Nets

DEFF Research Database (Denmark)

Bertolini, Cristiano; Liu, Zhiming; Srba, Jiri

2013-01-01

Workflows in modern healthcare systems are becoming increasingly complex and their execution involves concurrency and sharing of resources. The definition, analysis and management of collaborative healthcare workflows requires abstract model notations with a precisely defined semantics and a supp......Workflows in modern healthcare systems are becoming increasingly complex and their execution involves concurrency and sharing of resources. The definition, analysis and management of collaborative healthcare workflows requires abstract model notations with a precisely defined semantics...

CPN/Tools: A Tool for Editing and Simulating Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt; Christensen, Søren; Ravn, Katrine

2001-01-01

the workspace. It challenges traditional ideas about user interfaces, getting rid of pull-down menus, scrollbars, and even selection, while providing the same or greater functionality. CPN/Tools requires an OpenGL graphics accelerator and will run on all major platforms (Windows, Unix/Linux, MacOS)....

Safe Kids Worldwide

Science.gov (United States)

... Blog Videos Newsletter facebook twitter instagram pinterest gplus youtube Search Menu Why It Matters Who We Are What We Do Find Your Safe Kids Safe Kids Day Main menu Keeping All Kids Safe Safety Tips Get Involved 4 Star Charity Donate Text Burns and Scalds 4 tips ...

Current Status and Future Prospect of K-NET and KiK-net

Science.gov (United States)

Aoi, S.; Kunugi, T.; Suzuki, W.; Nakamura, H.; Fujiwara, H.

2014-12-01

During 18 years since the deployment of K-NET following the Kobe earthquake, our attention has mainly focused on rapidity of the data collection and an unfailing and reliable observation. In this presentation, we review three generations of the instruments employed by K-NET and KiK-net from these two points of view.At beginning of the 2000's, we newly developed the second generation instruments (K-NET02, K-NET02A, KiK-net06) to replace the first generation instruments (K-NET95, SMAC-MDK) employed when the networks were constructed in the 1990's. These instruments have an automatic dial-out function. It takes typically 2-5 s to establish communication and a few seconds to send the pre-trigger data. After that, data is available typically within a 1.5 s delay. Not only waveform data but also strong motion indexes such as real-time intensity, PGA, PGV, PGD, and response spectra are continuously sent once a second.After the 2011 Tohoku earthquake, we have developed the third generation instruments (K-NET11, KiK-net11) and have replaced almost half of the all stations country wide. Main improvement of this instrument is more unfailing and reliable observation. Because we have often experienced very large ground motions (e.g. 45 records exceeding gravity), the maximum measureable range was expanded from 2000 gal to 4000 gal for the second generation instrument, and to 8000 gal for the third. For the third generation instrument, in case of power failure, observation (including transmission of data) works for seven days thanks to the backup battery, while for the second generation instruments it works only for one day. By adding an oblique component to the three-component accelerometers, we could automatically distinguish shaking data from noise such as electric pulses which may cause a false alarm in EEW. Implementation to guarantee the continuity of observation under severe conditions such as during the Tohoku earthquake is very important, as well as a highly efficient

Markets, voucher subsidies and free nets combine to achieve high bed net coverage in rural Tanzania

Directory of Open Access Journals (Sweden)

Gerrets Rene PM

2008-06-01

Full Text Available Abstract Background Tanzania has a well-developed network of commercial ITN retailers. In 2004, the government introduced a voucher subsidy for pregnant women and, in mid 2005, helped distribute free nets to under-fives in small number of districts, including Rufiji on the southern coast, during a child health campaign. Contributions of these multiple insecticide-treated net delivery strategies existing at the same time and place to coverage in a poor rural community were assessed. Methods Cross-sectional household survey in 6,331 members of randomly selected 1,752 households of 31 rural villages of Demographic Surveillance System in Rufiji district, Southern Tanzania was conducted in 2006. A questionnaire was administered to every consenting respondent about net use, treatment status and delivery mechanism. Findings Net use was 62.7% overall, 87.2% amongst infants (0 to1 year, 81.8% amongst young children (>1 to 5 years, 54.5% amongst older children (6 to 15 years and 59.6% amongst adults (>15 years. 30.2% of all nets had been treated six months prior to interview. The biggest source of nets used by infants was purchase from the private sector with a voucher subsidy (41.8%. Half of nets used by young children (50.0% and over a third of those used by older children (37.2% were obtained free of charge through the vaccination campaign. The largest source of nets amongst the population overall was commercial purchase (45.1% use and was the primary means for protecting adults (60.2% use. All delivery mechanisms, especially sale of nets at full market price, under-served the poorest but no difference in equity was observed between voucher-subsidized and freely distributed nets. Conclusion All three delivery strategies enabled a poor rural community to achieve net coverage high enough to yield both personal and community level protection for the entire population. Each of them reached their relevant target group and free nets only temporarily

Initial CAD investigations for NET

International Nuclear Information System (INIS)

Katz, F.; Leinemann, K.; Ludwig, A.; Marek, U.; Olbrich, W.; Schlechtendahl, E.G.

1985-11-01

This report summarizes the work done under contract no. 164/84-7/FU-D-/NET between the Commission of the European Communities and KfK during the period from June 1, 1984, through May 31, 1985. The following topics are covered in this report: Initial modelling of NET version NET2A, CAD system extension for remote handling studies, analysis of the CAD information structure, work related to the transfer of CAD information between KfK and the NET team. (orig.) [de

NetBeans IDE 8 cookbook

CERN Document Server

Salter, David

2014-01-01

If you're a Java developer of any level using NetBeans and want to learn how to get the most out of NetBeans, then this book is for you. Learning how to utilize NetBeans will provide a firm foundation for your Java application development.

The Net Advance of Physics

Science.gov (United States)

THE NET ADVANCE OF PHYSICS Review Articles and Tutorials in an Encyclopædic Format Established 1995 [Link to MIT] Computer support for The Net Advance of Physics is furnished by The Massachusetts Newest Additions SPECIAL FEATURES: Net Advance RETRO: Nineteenth Century Physics History of Science

Improved netting

International Nuclear Information System (INIS)

Bramley, A.; Clabburn, R.J.T.

1976-01-01

A method is described for producing netting composed of longitudinal and transverse threads of irradiation cross linked thermoplastic material, the threads being joined together at their crossings by moulded masses of cross linked thermoplastic material. The thread may be formed of polyethylene filaments, subjected to a radiation dose of 15 to 25 MR. The moulding can be conducted at 245 0 to 260 0 C or higher. The product is claimed to be an improved quality of netting, with bonds of increased strength between crossing threads. (U.K.)

Net alkalinity and net acidity 1: Theoretical considerations

International Nuclear Information System (INIS)

Kirby, Carl S.; Cravotta, Charles A.

2005-01-01

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO 2 , and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined 'CO 2 -acidity' is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO 2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass-action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mgL -1 as CaCO 3 (based on pH and analytical concentrations of dissolved Fe II , Fe III , Mn, and Al in mgL -1 ):acidity calculated =50{1000(10 -pH )+[2(Fe II )+3(Fe III )]/56+2(Mn) /55+3(Al)/27}underestimates contributions from HSO 4 - and H + , but overestimates the acidity due to Fe 3+ and Al 3+ . However, these errors tend to approximately cancel each other. It is demonstrated that 'net alkalinity' is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the

Net alkalinity and net acidity 1: Theoretical considerations

Science.gov (United States)

Kirby, C.S.; Cravotta, C.A.

2005-01-01

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO2, and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined "CO 2-acidity" is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass- action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mg L -1 as CaCO3 (based on pH and analytical concentrations of dissolved FeII, FeIII, Mn, and Al in mg L -1):aciditycalculated=50{1000(10-pH)+[2(FeII)+3(FeIII)]/56+2(Mn)/ 55+3(Al)/27}underestimates contributions from HSO4- and H+, but overestimates the acidity due to Fe3+ and Al3+. However, these errors tend to approximately cancel each other. It is demonstrated that "net alkalinity" is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation, (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the value obtained in a

Proof Nets for Lambek Calculus

NARCIS (Netherlands)

Roorda, Dirk

1992-01-01

The proof nets of linear logic are adapted to the non-commutative Lambek calculus. A different criterion for soundness of proof nets is given, which gives rise to new algorithms for proof search. The order sensitiveness of the Lambek calculus is reflected by the planarity condition on proof nets;

Highly Undecidable Questions for Process Algebras

DEFF Research Database (Denmark)

Srba, Jiri; Jancar, Petr

2004-01-01

We show Sigma^1_1-completeness of weak bisimilarity for PA (process algebra), and of wek simulation preorder/equivalence for PDA (pushdown automata), PA and PN (Petri nets). We also show Pi^1_1-hardness of weak omega-trace equivalence for the sub(classes) of BPA (basic process algebra) and BPP...

Modelling and simulation of signal transductions in an apoptosis ...

Indian Academy of Sciences (India)

Prakash

Structural Analysis of Metabolic Networks: Elementary Flux. Mode, Analogy to Petri Nets, and Application to Mycoplasma pneumoniae; German Conference on Bioinformatics 2000 pp 115–120. Takai-Igarashi T and Mizoguchi R 2004 Cell signalling networks ontology; In Silico Biol. 4 81–87. Thompson C 1995 Apoptosis in ...

Comparative process mining in education : an approach based on process cubes

NARCIS (Netherlands)

van der Aalst, W.M.P.; Guo, S.; Gorissen, P.J.B.; Ceravolo, P.; Accorsi, R.; Cudre-Mauroux, P.

2015-01-01

Process mining techniques enable the analysis of a wide variety of processes using event data. For example, event logs can be used to automatically learn a process model (e.g., a Petri net or BPMN model). Next to the automated discovery of the real underlying process, there are process mining

A quantitative analysis of faulty EPCs in the SAP reference model

NARCIS (Netherlands)

Mendling, J.; Moser, M.; Neumann, G.; Verbeek, H.M.W.; Dongen, van B.F.; Aalst, van der W.M.P.

2006-01-01

The SAP reference model contains more than 600 non-trivial process models expressed in terms of Event-driven Process Chains (EPCs). We have automatically translated these EPCs into YAWL models and analyzed these models usingWofYAWL, a veri¯cation tool based on Petri nets. We discovered that at least

Mixing Paradigms for More Comprehensible Models

DEFF Research Database (Denmark)

Westergaard, Michael; Slaats, Tijs

2013-01-01

Petri nets efficiently model both data- and control-flow. Control-flow is either modeled explicitly as flow of a specific kind of data, or implicit based on the data-flow. Explicit modeling of control-flow is useful for well-known and highly structured processes, but may make modeling of abstract...

Properties of porous netted materials

International Nuclear Information System (INIS)

Daragan, V.D.; Drozdov, B.G.; Kotov, A.Yu.; Mel'nikov, G.N.; Pustogarov, A.V.

1987-01-01

Hydraulic and strength characteristics, efficient heat conduction and inner heat exchange coefficient are experimentally studied for porous netted materials on the base of the brass nets as dependent on porosity, cell size and method of net laying. Results of the studies are presented. It is shown that due to anisotropy of the material properties the hydraulic resistance in the direction parallel to the nets plane is 1.3-1.6 times higher than in the perpendicular one. Values of the effective heat conduction in the direction perpendicular to the nets plane at Π>0.45 agree with the data from literature, at Π<0.45 a deviation from the calculated values is marked in the direction of the heat conduction decrease

"Same Room, Safe Place".

Science.gov (United States)

Keene Woods, Nikki

2017-04-01

There are many different professional stances on safe sleep and then there is the reality of caring for a newborn. There is a debate among professionals regarding safe sleep recommendations. The continum of recommendations vary from the American Academy of Pediatrics (AAP) Safe Sleep Guidelines to the bed-sharing recommendations from the Mother-Baby Behavioral Sleep Laboratory. The lack of consistent and uniform safe sleep recommendations from health professionals has been confusing for families but has more recently raised a real professional ethical dilemma. Despite years of focused safe sleep community education and interventions, sleep-related infant deaths are on the rise in many communities. This commentary calls for a united safe sleep message from all health professionals to improve health for mothers and infants most at-risk, "Same Room, Safe Place."

MODELADO CON REDES DE PETRI E IMPLEMENTACIÓN CON GRAFCET DE UN SISTEMA DE MANUFACTURA FLEXIBLE CON PROCESOS CONCURRENTES Y RECURSOS COMPARTIDOS

OpenAIRE

Johanna Stella Castellanos Arias; Leonardo Enrique Solaque Guzmán

2010-01-01

En este trabajo, se presenta el modelado de un Sistema de Manufactura Flexible (SMF), con procesos concurrentes y recursos compartidos mediante Sistemas a Eventos Discretos (SED), específicamente Redes de Petri (RdP), y GRAFCET. El SMF se plantea como un modelo hipotético que se modela con una RdP con el objeto de identificar su dinámica y hallar la secuencia óptima de funcionamiento del sistema. Se desarrolló un modelo matemático que permite estimar el vector de tiempo acumulado de un proces...

Understanding Net Zero Energy Buildings

DEFF Research Database (Denmark)

Salom, Jaume; Widén, Joakim; Candanedo, José

2011-01-01

Although several alternative definitions exist, a Net-Zero Energy Building (Net ZEB) can be succinctly described as a grid-connected building that generates as much energy as it uses over a year. The “net-zero” balance is attained by applying energy conservation and efficiency measures...... and by incorporating renewable energy systems. While based on annual balances, a complete description of a Net ZEB requires examining the system at smaller time-scales. This assessment should address: (a) the relationship between power generation and building loads and (b) the resulting interaction with the power grid...

Pro ASP.NET 4 in VB 2010

CERN Document Server

MacDonald, Matthew; Freeman, Adam; Szpuszta, Mario; Agarwal, Vidya Vrat

2010-01-01

ASP.NET 4 is the latest version of Microsoft's revolutionary ASP.NET technology. It is the principal standard for creating dynamic web pages on the Windows platform. Pro ASP.NET 4 in VB 2010 raises the bar for high-quality, practical advice on learning and deploying Microsoft's dynamic web solution. This new edition is updated with everything you need to come to grips with the latest version of ASP.NET, including coverage of ASP.NET MVC, ASP.NET AJAX 4, ASP.NET Dynamic Data, and Silverlight 3. Seasoned .NET professionals Matthew MacDonald and Mario Szpuszta explain how you can get the most fro

NET European Network on Neutron Techniques Standardization for Structural Integrity

International Nuclear Information System (INIS)

Youtsos, A.

2004-01-01

Improved performance and safety of European energy production systems is essential for providing safe, clean and inexpensive electricity to the citizens of the enlarged EU. The state of the art in assessing internal stresses, micro-structure and defects in welded nuclear components -as well as their evolution due to complex thermo-mechanical loads and irradiation exposure -needs to be improved before relevant structural integrity assessment code requirements can safely become less conservative. This is valid for both experimental characterization techniques and predictive numerical algorithms. In the course of the last two decades neutron methods have proven to be excellent means for providing valuable information required in structural integrity assessment of advanced engineering applications. However, the European industry is hampered from broadly using neutron research due to lack of harmonised and standardized testing methods. 35 European major industrial and research/academic organizations have joined forces, under JRC coordination, to launch the NET European Network on Neutron Techniques Standardization for Structural Integrity in May 2002. The NET collaborative research initiative aims at further development and harmonisation of neutron scattering methods, in support of structural integrity assessment. This is pursued through a number of testing round robin campaigns on neutron diffraction and small angle neutron scattering - SANS and supported by data provided by other more conventional destructive and non-destructive methods, such as X-ray diffraction and deep and surface hole drilling. NET also strives to develop more reliable and harmonized simulation procedures for the prediction of residual stress and damage in steel welded power plant components. This is pursued through a number of computational round robin campaigns based on advanced FEM techniques, and on reliable data obtained by such novel and harmonized experimental methods. The final goal of

NASA Net Zero Energy Buildings Roadmap

Energy Technology Data Exchange (ETDEWEB)

Pless, S.; Scheib, J.; Torcellini, P.; Hendron, B.; Slovensky, M.

2014-10-01

In preparation for the time-phased net zero energy requirement for new federal buildings starting in 2020, set forth in Executive Order 13514, NASA requested that the National Renewable Energy Laboratory (NREL) to develop a roadmap for NASA's compliance. NASA detailed a Statement of Work that requested information on strategic, organizational, and tactical aspects of net zero energy buildings. In response, this document presents a high-level approach to net zero energy planning, design, construction, and operations, based on NREL's first-hand experience procuring net zero energy construction, and based on NREL and other industry research on net zero energy feasibility. The strategic approach to net zero energy starts with an interpretation of the executive order language relating to net zero energy. Specifically, this roadmap defines a net zero energy acquisition process as one that sets an aggressive energy use intensity goal for the building in project planning, meets the reduced demand goal through energy efficiency strategies and technologies, then adds renewable energy in a prioritized manner, using building-associated, emission- free sources first, to offset the annual energy use required at the building; the net zero energy process extends through the life of the building, requiring a balance of energy use and production in each calendar year.

RESTful NET

CERN Document Server

Flanders, Jon

2008-01-01

RESTful .NET is the first book that teaches Windows developers to build RESTful web services using the latest Microsoft tools. Written by Windows Communication Foundation (WFC) expert Jon Flanders, this hands-on tutorial demonstrates how you can use WCF and other components of the .NET 3.5 Framework to build, deploy and use REST-based web services in a variety of application scenarios. RESTful architecture offers a simpler approach to building web services than SOAP, SOA, and the cumbersome WS- stack. And WCF has proven to be a flexible technology for building distributed systems not necessa

Getting to Net Zero

Energy Technology Data Exchange (ETDEWEB)

2016-09-01

The technology necessary to build net zero energy buildings (NZEBs) is ready and available today, however, building to net zero energy performance levels can be challenging. Energy efficiency measures, onsite energy generation resources, load matching and grid interaction, climatic factors, and local policies vary from location to location and require unique methods of constructing NZEBs. It is recommended that Components start looking into how to construct and operate NZEBs now as there is a learning curve to net zero construction and FY 2020 is just around the corner.

Net Zero Energy Buildings

DEFF Research Database (Denmark)

Marszal, Anna Joanna; Bourrelle, Julien S.; Gustavsen, Arild

2010-01-01

and identify possible renewable energy supply options which may be considered in calculations. Finally, the gap between the methodology proposed by each organisation and their respective national building code is assessed; providing an overview of the possible changes building codes will need to undergo......The international cooperation project IEA SHC Task 40 / ECBCS Annex 52 “Towards Net Zero Energy Solar Buildings”, attempts to develop a common understanding and to set up the basis for an international definition framework of Net Zero Energy Buildings (Net ZEBs). The understanding of such buildings...

Pro NET Best Practices

CERN Document Server

Ritchie, Stephen D

2011-01-01

Pro .NET Best Practices is a practical reference to the best practices that you can apply to your .NET projects today. You will learn standards, techniques, and conventions that are sharply focused, realistic and helpful for achieving results, steering clear of unproven, idealistic, and impractical recommendations. Pro .NET Best Practices covers a broad range of practices and principles that development experts agree are the right ways to develop software, which includes continuous integration, automated testing, automated deployment, and code analysis. Whether the solution is from a free and

ASP.NET web API build RESTful web applications and services on the .NET framework

CERN Document Server

Kanjilal, Joydip

2013-01-01

This book is a step-by-step, practical tutorial with a simple approach to help you build RESTful web applications and services on the .NET framework quickly and efficiently.This book is for ASP.NET web developers who want to explore REST-based services with C# 5. This book contains many real-world code examples with explanations whenever necessary. Some experience with C# and ASP.NET 4 is expected.

A formal modeling approach for supply chain event management

NARCIS (Netherlands)

Liu, R.; Kumar, Akhil; Aalst, van der W.M.P.

2007-01-01

As supply chains become more dynamic, there is a need for a sense-and-respond capability to react to events in a real-time manner. In this paper, we propose Petri nets extended with time and color (to represent case data) as a formalism for managing events. We designed seven basic patterns to

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Sadhana. S G Deshmukh. Articles written in Sadhana. Volume 30 Issue 2-3 April-June 2005 pp 403-429. e-Commerce and supply chains: Modelling of dynamics through fuzzy enhanced high level petri net · Vipul Jain S Wadhwa S G Deshmukh · More Details Abstract Fulltext PDF. Although information ...

Programming NET 35

CERN Document Server

Liberty, Jesse

2009-01-01

Bestselling author Jesse Liberty and industry expert Alex Horovitz uncover the common threads that unite the .NET 3.5 technologies, so you can benefit from the best practices and architectural patterns baked into the new Microsoft frameworks. The book offers a Grand Tour" of .NET 3.5 that describes how the principal technologies can be used together, with Ajax, to build modern n-tier and service-oriented applications. "

Net metering: zero electricity bill

International Nuclear Information System (INIS)

Mangi, A.; Khan, Z.

2011-01-01

Worldwide move towards renewable energy sources, environmental concerns and decentralization of the power sector have made net metering an attractive option for power generation at small scale. This paper discusses the net metering, economical issues of renewable sources in Pakistan, technical aspects, installation suitability according to varying terrain, existing utility rules and formulation of legislation for net metering making it economically attractive. (author)

DroidSafe

Science.gov (United States)

2016-12-01

Massachusetts Avenue, Build E19-750 Cambridge , MA 02139-4307 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS...Activity objects illustrating the challenges of points-to and information flow analysis...measure how many malicious flows Droid- Safe was able to detect). As these results illustrate , DroidSafe implements an analysis of unprece- dented

Safe havens in Europe

DEFF Research Database (Denmark)

Paldam, Martin

2013-01-01

Eleven safe havens exist in Europe providing offshore banking and low taxes. Ten of these states are very small while Switzerland is moderately small. All 11 countries are richer than their large neighbors. It is shown that causality is from small to safe haven to wealth, and that theoretically...... equilibriums are likely to exist where a certain regulation is substantially lower in a small country than in its big neighbor. This generates a large capital inflow to the safe havens. The pool of funds that may reach the safe havens is shown to be huge. It is far in excess of the absorptive capacity...... of the safe havens, but it still explains, why they are rich. Microstates offer a veil of anonymity to funds passing through, and Switzerland offers safe storage of funds....

Net Locality

DEFF Research Database (Denmark)

de Souza e Silva, Adriana Araujo; Gordon, Eric

Provides an introduction to the new theory of Net Locality and the profound effect on individuals and societies when everything is located or locatable. Describes net locality as an emerging form of location awareness central to all aspects of digital media, from mobile phones, to Google Maps......, to location-based social networks and games, such as Foursquare and facebook. Warns of the threats these technologies, such as data surveillance, present to our sense of privacy, while also outlining the opportunities for pro-social developments. Provides a theory of the web in the context of the history...... of emerging technologies, from GeoCities to GPS, Wi-Fi, Wiki Me, and Google Android....

Traveling Safely with Medicines

Science.gov (United States)

... Medications Safely My Medicine List How to Administer Traveling Safely with Medicines Planes, trains, cars – even boats ... your trip, ask your pharmacist about how to travel safely with your medicines. Make sure that you ...

Construction of monophase nets

International Nuclear Information System (INIS)

Suarez A, Jose Antonio

1996-01-01

The paper refers to the use of monophase loads in commercial residential urbanizations and in small industries, for this reason it is considered unnecessary the construction of three-phase nets. The author makes a historical recount of these nets in Bogota, his capacities, uses and energy savings

Formal Verification of Real-Time System Requirements

Directory of Open Access Journals (Sweden)

Marcin Szpyrka

2000-01-01

Full Text Available The methodology of system requirements verification presented in this paper is a proposition of a practical procedure for reducing some negatives of the specification of requirements. The main problem that is considered is to create a complete description of the system requirements without any negatives. Verification of the initially defined requirements is based on the coloured Petri nets. Those nets are useful for testing some properties of system requirements such as completeness, consistency and optimality. An example ofthe litt controller is presented.

Caught in the Net: Perineuronal Nets and Addiction

Directory of Open Access Journals (Sweden)

Megan Slaker

2016-01-01

Full Text Available Exposure to drugs of abuse induces plasticity in the brain and creates persistent drug-related memories. These changes in plasticity and persistent drug memories are believed to produce aberrant motivation and reinforcement contributing to addiction. Most studies have explored the effect drugs of abuse have on pre- and postsynaptic cells and astrocytes; however, more recently, attention has shifted to explore the effect these drugs have on the extracellular matrix (ECM. Within the ECM are unique structures arranged in a net-like manner, surrounding a subset of neurons called perineuronal nets (PNNs. This review focuses on drug-induced changes in PNNs, the molecules that regulate PNNs, and the expression of PNNs within brain circuitry mediating motivation, reward, and reinforcement as it pertains to addiction.

Constant speed control of four-stroke micro internal combustion swing engine

Science.gov (United States)

Gao, Dedong; Lei, Yong; Zhu, Honghai; Ni, Jun

2015-09-01

The increasing demands on safety, emission and fuel consumption require more accurate control models of micro internal combustion swing engine (MICSE). The objective of this paper is to investigate the constant speed control models of four-stroke MICSE. The operation principle of the four-stroke MICSE is presented based on the description of MICSE prototype. A two-level Petri net based hybrid model is proposed to model the four-stroke MICSE engine cycle. The Petri net subsystem at the upper level controls and synchronizes the four Petri net subsystems at the lower level. The continuous sub-models, including breathing dynamics of intake manifold, thermodynamics of the chamber and dynamics of the torque generation, are investigated and integrated with the discrete model in MATLAB Simulink. Through the comparison of experimental data and simulated DC voltage output, it is demonstrated that the hybrid model is valid for the four-stroke MICSE system. A nonlinear model is obtained from the cycle average data via the regression method, and it is linearized around a given nominal equilibrium point for the controller design. The feedback controller of the spark timing and valve duration timing is designed with a sequential loop closing design approach. The simulation of the sequential loop closure control design applied to the hybrid model is implemented in MATLAB. The simulation results show that the system is able to reach its desired operating point within 0.2 s, and the designed controller shows good MICSE engine performance with a constant speed. This paper presents the constant speed control models of four-stroke MICSE and carries out the simulation tests, the models and the simulation results can be used for further study on the precision control of four-stroke MICSE.

Modelling a radiology department service using a VDL integrated approach.

Science.gov (United States)

Guglielmino, Maria Gabriella; Celano, Giovanni; Costa, Antonio; Fichera, Sergio

2009-01-01

The healthcare industry is facing several challenges such as the reduction of costs and quality improvement of the provided services. Engineering studies could be very useful in supporting organizational and management processes. Healthcare service efficiency depends on a strong collaboration between clinical and engineering experts, especially when it comes to analyzing the system and its constraints in detail and subsequently, when it comes to deciding on the reengineering of some key activities. The purpose of this paper is to propose a case study showing how a mix of representation tools allow a manager of a radiology department to solve some human and technological resource re-organizational issues, which have to be faced due to the introduction of a new technology and a new portfolio of services. In order to simulate the activities within the radiology department and examine the relationship between human and technological resources, different visual diagrammatic language (VDL) techniques have been implemented to get knowledge about the heterogeneous factors related to the healthcare service delivery. In particular, flow charts, IDEFO diagrams and Petri nets have been integrated each other with success as a modelisation tools. The simulation study performed through the application of the aforementioned VDL techniques suggests the opportunity of re-organizing the nurse activities within the radiology department. The re-organization of a healthcare service and in particular of a radiology department by means of joint flow charts, IDEF0 diagrams and Petri nets is a poorly investigated topic in literature. This paper demonstrates how flow charts and IDEF0 can help people working within the department to understand the weak points of their organization and constitute an efficient base of knowledge for the implementation of a Petri net aimed at improving the departmental performance.

An experimental evaluation of passage-based process discovery

NARCIS (Netherlands)

Verbeek, H.M.W.; Aalst, van der W.M.P.; La Rosa, M.; Soffer, P.

2013-01-01

In the area of process mining, the ILP Miner is known for the fact that it always returns a Petri net that perfectly fits a given event log. Like for most process discovery algorithms, its complexity is linear in the size of the event log and exponential in the number of event classes (i.e.,

RMIT at the TREC 2015 LiveQA Track

Science.gov (United States)

2015-11-20

recipient of an Australian Research Council DECRA Research Fellowship (DE140100275). REFERENCES [1] Michael Collins. Head-driven statistical models for...18th Australasian Document Computing Symposium, pages 58–65. ACM, 2013. [4] Matthias Petri, Alistair Moffat, and J Shane Culpepper. Score-safe term

The K-NET - A year after

International Nuclear Information System (INIS)

Kinoshita, S.; Ohtani, K.; Katayama, T.

2001-01-01

We started to release the K-NET strong-motion data from June 1996 and about one year passed. In this article, we report the development of K-NET and some applications using the K-NET information released on the Internet. (author)

Mars MetNet Mission Status

Science.gov (United States)

Harri, A.-M.; Aleksashkin, S.; Arruego, I.; Schmidt, W.; Genzer, M.; Vazquez, L.; Haukka, H.; Palin, M.; Nikkanen, T.

2015-10-01

New kind of planetary exploration mission for Mars is under development in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semihard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor [1] mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide significant insights in to the Martian atmospheric behavior. The key technologies of the MetNet Lander have been qualified and the electrical qualification model (EQM) of the payload bay has been built and successfully tested.

Modeling of the maintenance policy of an offshore wind farm

International Nuclear Information System (INIS)

Maddens, L.; Labeau, P.E.

2004-01-01

Wind energy has a key position in the market of renewable electricity production means. Offshore wind farms offer additional surfaces to exploit this form of energy, together with more favourable wind conditions. Yet offshore windmills ask for higher investment and maintenance costs. Optimising the latter costs should therefore turn out to be particularly beneficial for this technology. The present paper summarizes the main modelling aspects of the maintenance of a typical offshore wind farm, such as the accessibility of the wind turbines and the impact of weather conditions, the cost of the different transport resources, the number of maintenance teams, a tolerated unavailability of part of the windmills, the opportunity to combine corrective and preventive maintenance actions on one or several windmills. All these features were embedded in a Petri net model of the maintenance policy of the farm, allowing to estimate the maintenance costs entailed by several strategies. Advantages and drawbacks of using Petri nets for the modelling of such a maintenance strategy are finally discussed. (authors)

NET SALARY ADJUSTMENT

CERN Multimedia

Finance Division

2001-01-01

On 15 June 2001 the Council approved the correction of the discrepancy identified in the net salary adjustment implemented on 1st January 2001 by retroactively increasing the scale of basic salaries to achieve the 2.8% average net salary adjustment approved in December 2000. We should like to inform you that the corresponding adjustment will be made to your July salary. Full details of the retroactive adjustments will consequently be shown on your pay slip.

Translating Unstructured Workflow Processes to Readable BPEL: Theory and Implementation

DEFF Research Database (Denmark)

van der Aalst, Willibrordus Martinus Pancratius; Lassen, Kristian Bisgaard

2008-01-01

The Business Process Execution Language for Web Services (BPEL) has emerged as the de-facto standard for implementing processes. Although intended as a language for connecting web services, its application is not limited to cross-organizational processes. It is expected that in the near future...... and not easy to use by end-users. Therefore, we provide a mapping from Workflow Nets (WF-nets) to BPEL. This mapping builds on the rich theory of Petri nets and can also be used to map other languages (e.g., UML, EPC, BPMN, etc.) onto BPEL. In addition to this we have implemented the algorithm in a tool called...

Net energy gain from DT fusion

International Nuclear Information System (INIS)

Buende, R.

1985-01-01

The net energy which can be gained from an energy raw material by means of a certain conversion system is deduced as the figure-of-merit which adequately characterizes the net energy balance of utilizing an energy source. This potential net energy gain is determined for DT fusion power plants. It is represented as a function of the degree of exploitation of the energy raw material lithium ore and is compared with the net energy which can be gained with LW and FBR power plants by exploiting uranium ore. The comparison clearly demonstrates the net energetic advantage of DT fusion. A sensitivity study shows that this holds even if the energy expenditure for constructing and operating is drastically increased

Net alkalinity and net acidity 2: Practical considerations

Science.gov (United States)

Kirby, C.S.; Cravotta, C.A.

2005-01-01

The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH mine drainage treatment can lead to systems with insufficient Alkalinity to neutralize metal and H+ acidity and is not recommended. The use of net alkalinity = -Hot Acidity titration is recommended for the planning of mine drainage treatment. The use of net alkalinity = (Alkalinitymeasured - Aciditycalculated) is recommended with some cautions

Bed net ownership in Kenya: the impact of 3.4 million free bed nets

Directory of Open Access Journals (Sweden)

Vulule John

2010-06-01

Full Text Available Abstract Background In July and September 2006, 3.4 million long-lasting insecticide-treated bed nets (LLINs were distributed free in a campaign targeting children 0-59 months old (CU5s in the 46 districts with malaria in Kenya. A survey was conducted one month after the distribution to evaluate who received campaign LLINs, who owned insecticide-treated bed nets and other bed nets received through other channels, and how these nets were being used. The feasibility of a distribution strategy aimed at a high-risk target group to meet bed net ownership and usage targets is evaluated. Methods A stratified, two-stage cluster survey sampled districts and enumeration areas with probability proportional to size. Handheld computers (PDAs with attached global positioning systems (GPS were used to develop the sampling frame, guide interviewers back to chosen households, and collect survey data. Results In targeted areas, 67.5% (95% CI: 64.6, 70.3% of all households with CU5s received campaign LLINs. Including previously owned nets, 74.4% (95% CI: 71.8, 77.0% of all households with CU5s had an ITN. Over half of CU5s (51.7%, 95% CI: 48.8, 54.7% slept under an ITN during the previous evening. Nearly forty percent (39.1% of all households received a campaign net, elevating overall household ownership of ITNs to 50.7% (95% CI: 48.4, 52.9%. Conclusions The campaign was successful in reaching the target population, families with CU5s, the risk group most vulnerable to malaria. Targeted distribution strategies will help Kenya approach indicator targets, but will need to be combined with other strategies to achieve desired population coverage levels.

47 CFR 65.450 - Net income.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Net income. 65.450 Section 65.450... OF RETURN PRESCRIPTION PROCEDURES AND METHODOLOGIES Exchange Carriers § 65.450 Net income. (a) Net income shall consist of all revenues derived from the provision of interstate telecommunications services...

The Micro-Pulse Lidar Network (MPL-Net)

Science.gov (United States)

Welton, Ellsworth J.; Campbell, James R.; Berkoff, Timothy A.; Spinhirne, James D.; Tsay, Si-Chee; Holben, Brent; Shiobara, Masataka; Starr, David OC. (Technical Monitor)

2002-01-01

In the early 1990s, the first small, eye-safe, and autonomous lidar system was developed, the Micro-pulse Lidar (MPL). The MPL has proven to be useful in the field because it can be automated, runs continuously (day and night), is eye-safe, can easily be transported and set up, and has a small field-of-view which limits multiple scattering concerns. The MPL acquires signal profiles of backscattered laser light from aerosols and clouds. The signals are analyzed to yield multiple layer heights, optical depths of each layer, average extinction-to-backscatter ratio of each layer, and profiles of extinction in each layer. The MPL has been used in a wide variety of field studies over the past 10 years, leading to nearly 20 papers and many conference presentations. In 2000, a new project using MPL systems was started at NASA Goddard Space Flight Center. The MPL-Net project is currently working to establish a worldwide network of MPL systems, all co-located with NASA's AERONET sunphotometers for joint measurements of optical depth and sky radiance. Automated processing algorithms have been developed to produce data products on a next day basis for all sites and some field experiments. Initial results from the first several sites are shown, along with aerosol data collected during several major field campaigns. Measurements of the aerosol extinction-to-backscatter ratio at several different geographic regions, and for various aerosol types are shown. This information is used to improve the construction of look up tables of the ratio, needed to process aerosol profiles acquired with satellite based lidars.

Business Profile of Boat Lift Net and Stationary Lift Net Fishing Gear in Morodemak Waters Central Java

Science.gov (United States)

Hapsari, Trisnani D.; Jayanto, Bogi B.; Fitri, Aristi D. P.; Triarso, I.

2018-02-01

Lift net is one of the fishing gears that is used widely in the Morodemak coastal fishing port (PPP) for catching pelagic fish. The yield of fish captured by these fishing gear has high economic value, such as fish belt (Trichiurus sp), squids (Loligo sp) and anchovies (Stelophorus sp). The aims of this research were to determine the technical aspects of boat lift net and stationary lift net fishing gear in Morodemak Waters Demak Regency; to find out the financial aspect of those fishing gears and to analyze the financial feasibility by counting PP, NPV, IRR, and B/C ratio criteria. This research used case study method with descriptive analysis. The sampling method was purposive sampling with 22 fishermen as respondents. The result of the research showed that the average of boat lift net acceptance was Rp 388,580,000. The financial analysis of fisheries boat lift net with the result of NPV Rp 836,149,272, PP 2.44 years, IRR value 54%, and B/C ratio 1.73. The average of stationary lift net acceptance was Rp 27,750,000. The financial analysis lift net with the result of NPV Rp 37,937,601; PP 1.96 years, IRR value 86%, and B/C ratio 1.32. This research had a positive NPV value, B/C ratio >1, and IRR > discount rate (12 %). This study concluded that the fishery business of boat lift net and stationary lift net in Morodemak coastal fishing port (PPP) was worth running.

Net neutrality and audiovisual services

OpenAIRE

van Eijk, N.; Nikoltchev, S.

2011-01-01

Net neutrality is high on the European agenda. New regulations for the communication sector provide a legal framework for net neutrality and need to be implemented on both a European and a national level. The key element is not just about blocking or slowing down traffic across communication networks: the control over the distribution of audiovisual services constitutes a vital part of the problem. In this contribution, the phenomenon of net neutrality is described first. Next, the European a...

47 CFR 65.500 - Net income.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Net income. 65.500 Section 65.500... OF RETURN PRESCRIPTION PROCEDURES AND METHODOLOGIES Interexchange Carriers § 65.500 Net income. The net income methodology specified in § 65.450 shall be utilized by all interexchange carriers that are...

Aplicació Microsoft .Net : Hotel Spa

OpenAIRE

Marquès Palmer, Jordi

2010-01-01

Desenvolupament d'una aplicació amb Microsoft .NET, WCF, WPF, Linq2SQL, d'un Hotel Spa. Desarrollo de una aplicación con Microsoft .NET, WCF, WPF, Linq2SQL, de un Hotel Spa. Application development using Microsoft .NET, WCF, WPF, Linq2SQL, for a Spa Hotel.

WE-NET substask 3. Conceptual design of total system (Safety measures and evaluation techniques); 1998 nendo suiso riyo kokusai clean energy system gijutsu (WE-NET). 3. Zentai system gainen sekkei anzen taisaku hyoka gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

Under the hydrogen-utilizing international clean energy system technology project WE-NET (World Energy NET Work) in fiscal 1998, researches and studies were conducted to clearly define safety designs and to improve on accident-and-safety analyses. In relation with system safety design, investigations continued into Japanese and foreign manuals and regulations about the handling of hydrogen and its peripherals, and safe design guidelines (draft) were compiled. Anomalies and accidents supposed to be typical of each of the systems concerned were investigated. As for accident-and-safety analyses, incorporation of a turbulence model was studied in relation to models representing the leak, evaporation, and diffusion of liquid hydrogen, and improvement was achieved when the scope of evaluation was enlarged concerning the hydrogen detonation model. The integration of the two models was discussed for the due evaluation of a series of processes of liquid hydrogen leak, evaporation, diffusion, and detonation. Calculation was performed for two assumed accidents, and the results were found to justify the integration of the two models. (NEDO)

Automatic Prompt System in the Process of Mapping plWordNet on Princeton WordNet

Directory of Open Access Journals (Sweden)

Paweł Kędzia

2015-06-01

Full Text Available Automatic Prompt System in the Process of Mapping plWordNet on Princeton WordNet The paper offers a critical evaluation of the power and usefulness of an automatic prompt system based on the extended Relaxation Labelling algorithm in the process of (manual mapping plWordNet on Princeton WordNet. To this end the results of manual mapping – that is inter-lingual relations between plWN and PWN synsets – are juxtaposed with the automatic prompts that were generated for the source language synsets to be mapped. We check the number and type of inter-lingual relations introduced on the basis of automatic prompts and the distance of the respective prompt synsets from the actual target language synsets.

MPL-Net Measurements of Aerosol and Cloud Vertical Distributions at Co-Located AERONET Sites

Science.gov (United States)

Welton, Ellsworth J.; Campbell, James R.; Berkoff, Timothy A.; Spinhirne, James D.; Tsay, Si-Chee; Holben, Brent; Starr, David OC. (Technical Monitor)

2002-01-01

In the early 1990s, the first small, eye-safe, and autonomous lidar system was developed, the Micropulse Lidar (MPL). The MPL acquires signal profiles of backscattered laser light from aerosols and clouds. The signals are analyzed to yield multiple layer heights, optical depths of each layer, average extinction-to-backscatter ratios for each layer, and profiles of extinction in each layer. In 2000, several MPL sites were organized into a coordinated network, called MPL-Net, by the Cloud and Aerosol Lidar Group at NASA Goddard Space Flight Center (GSFC) using funding provided by the NASA Earth Observing System. tn addition to the funding provided by NASA EOS, the NASA CERES Ground Validation Group supplied four MPL systems to the project, and the NASA TOMS group contributed their MPL for work at GSFC. The Atmospheric Radiation Measurement Program (ARM) also agreed to make their data available to the MPL-Net project for processing. In addition to the initial NASA and ARM operated sites, several other independent research groups have also expressed interest in joining the network using their own instruments. Finally, a limited amount of EOS funding was set aside to participate in various field experiments each year. The NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) project also provides funds to deploy their MPL during ocean research cruises. All together, the MPL-Net project has participated in four major field experiments since 2000. Most MPL-Net sites and field experiment locations are also co-located with sunphotometers in the NASA Aerosol Robotic Network. (AERONET). Therefore, at these locations data is collected on both aerosol and cloud vertical structure as well as column optical depth and sky radiance. Real-time data products are now available from most MPL-Net sites. Our real-time products are generated at times of AERONET aerosol optical depth (AOD) measurements. The AERONET AOD is used as input to our

Loss of protection with insecticide-treated nets against pyrethroid-resistant Culex quinquefasciatus mosquitoes once nets become holed: an experimental hut study

Directory of Open Access Journals (Sweden)

Irish SR

2008-06-01

Full Text Available Abstract Background An important advantage of pyrethroid-treated nets over untreated nets is that once nets become worn or holed a pyrethroid treatment will normally restore protection. The capacity of pyrethroids to kill or irritate any mosquito that comes into contact with the net and prevent penetration of holes or feeding through the sides are the main reasons why treated nets continue to provide protection despite their condition deteriorating over time. Pyrethroid resistance is a growing problem among Anopheline and Culicine mosquitoes in many parts of Africa. When mosquitoes become resistant the capacity of treated nets to provide protection might be diminished, particularly when holed. An experimental hut trial against pyrethroid-resistant Culex quinquefasciatus was therefore undertaken in southern Benin using a series of intact and holed nets, both untreated and treated, to assess any loss of protection as nets deteriorate with use and time. Results There was loss of protection when untreated nets became holed; the proportion of mosquitoes blood feeding increased from 36.2% when nets were intact to between 59.7% and 68.5% when nets were holed to differing extents. The proportion of mosquitoes blood feeding when treated nets were intact was 29.4% which increased to 43.6–57.4% when nets were holed. The greater the number of holes the greater the loss of protection regardless of whether nets were untreated or treated. Mosquito mortality in huts with untreated nets was 12.9–13.6%; treatment induced mortality was less than 12%. The exiting rate of mosquitoes into the verandas was higher in huts with intact nets. Conclusion As nets deteriorate with use and become increasingly holed the capacity of pyrethroid treatments to restore protection is greatly diminished against resistant Culex quinquefasciatus mosquitoes.

Traditional nets interfere with the uptake of long-lasting insecticidal nets in the Peruvian Amazon: the relevance of net preference for achieving high coverage and use.

Directory of Open Access Journals (Sweden)

Koen Peeters Grietens

Full Text Available While coverage of long-lasting insecticide-treated nets (LLIN has steadily increased, a growing number of studies report gaps between net ownership and use. We conducted a mixed-methods social science study assessing the importance of net preference and use after Olyset® LLINs were distributed through a mass campaign in rural communities surrounding Iquitos, the capital city of the Amazonian region of Peru.The study was conducted in the catchment area of the Paujil and Cahuide Health Centres (San Juan district between July 2007 and November 2008. During a first qualitative phase, participant observation and in-depth interviews collected information on key determinants for net preference and use. In a second quantitative phase, a survey among recently confirmed malaria patients evaluated the acceptability and use of both LLINs and traditional nets, and a case control study assessed the association between net preference/use and housing structure (open vs. closed houses.A total of 10 communities were selected for the anthropological fieldwork and 228 households participated in the quantitative studies. In the study area, bed nets are considered part of the housing structure and are therefore required to fulfil specific architectural and social functions, such as providing privacy and shelter, which the newly distributed Olyset® LLINs ultimately did not. The LLINs' failure to meet these criteria could mainly be attributed to their large mesh size, transparency and perceived ineffectiveness to protect against mosquitoes and other insects, resulting in 63.3% of households not using any of the distributed LLINs. Notably, LLIN usage was significantly lower in houses with no interior or exterior walls (35.2% than in those with walls (73.8% (OR = 5.2, 95CI [2.2; 12.3], p<0.001.Net preference can interfere with optimal LLIN use. In order to improve the number of effective days of LLIN protection per dollar spent, appropriate quantitative and qualitative

HANPP Collection: Human Appropriation of Net Primary Productivity as a Percentage of Net Primary Productivity

Data.gov (United States)

National Aeronautics and Space Administration — The Human Appropriation of Net Primary Productivity (HANPP) as a Percentage of Net Primary Product (NPP) portion of the HANPP Collection represents a map identifying...

Net metering in British Columbia : white paper

International Nuclear Information System (INIS)

Berry, T.

2003-01-01

Net metering was described as being the reverse registration of an electricity customer's revenue meter when interconnected with a utility's grid. It is a provincial policy designed to encourage small-distributed renewable power generation such as micro-hydro, solar energy, fuel cells, and larger-scale wind energy. It was noted that interconnection standards for small generation is an important issue that must be addressed. The British Columbia Utilities Commission has asked BC Hydro to prepare a report on the merits of net metering in order to support consultations on a potential net metering tariff application by the utility. This report provides information on net metering with reference to experience in other jurisdictions with net metering, and the possible costs and benefits associated with net metering from both a utility and consumer perspective. Some of the barriers and policy considerations for successful implementation of net metering were also discussed. refs., tabs., figs