Valk, R., Petri nets as token objects: An introduction to elementary object nets, in: J. Desel and M. Silva, editors, 19th International Conference on Application and Theory of Petri Nets (1998), pp. 1--25.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....expression and data movement types. It cannot address the issues of architectural modeling though flexible enough for describing the semantics of code mobility at programming level. As a mathematical formalism, Petri nets have been applied to model active object and agent oriented systems [13] [34], 25] In the coordination model Objective Linda [13] a net is a combination of colored and timed Petri net, where tokens may be structured objects, and active objects are called agents. This model has considerable capability of specifying behaviors and coordination of parallel active objects ....

....objects, and active objects are called agents. This model has considerable capability of specifying behaviors and coordination of parallel active objects based on the generative communication. But, logical code mobility has not been examined clearly, let al..one at the architectural level. Valk [34] takes an object as a token in a unary elementary Petri net system, whereas the object itself is an elementary net system. So, an object can migrate across a net system. This bears some resemblance with LAM. Without consideration of architectural modeling, however, the transition firing in object ....

R.G. Valk, "Petri Nets as Token Objects: An Introduction to Elementary Object Nets," Application and Theory of Petri Nets, J. Desel and M. Silva, eds., pp. 1-25, 1998.

....is used only to define the semantics of synchronous channels and in the process of formally deriving properties of CP nets with channels. Synchronous channels are currently not part of the distributed version of Design CPN, but are included in the tool Renew [89] supporting reference nets [99]. Reference nets are essentially an extended version of CP nets where tokens can be reference nets themselves. This means that tokens are not only static information, but may have dynamic behaviour and change its own value (or state) Communication between reference nets (in tokens) is conducted ....

R. Valk. Petri Nets as Token Objects: An Introduction to Elementary Object Nets. In J. Desel and M. Silva, editors, Application and Theory of Petri Nets, volume 1420 of LNCS, pages 1--25. Springer-Verlag, 1998.

....expression and data movement types. It cannot address the issues of architectural modeling though flexible enough for describing the semantics of code mobility at programming level. As a mathematical formalism, Petri nets have been applied to model active object and agentoriented systems [13] [34], 25] In the coordination model Objective Linda [13] a net is a combination of colored and timed Petri net, where tokens may be structured objects, and active objects are called agents. This model has considerable capability of specifying behaviors and coordination of parallel active objects ....

....objects, and active objects are called agents. This model has considerable capability of specifying behaviors and coordination of parallel active objects based on the generative communication. But logical code mobility has not been examined clearly, let al..one at the architectural level. Valk [34] takes an object as a token in a unary elementary Petri net system, whereas the object itself is an elementary net system. So an object can migrate across a net system. This bears some resemblance with LAM. Without consideration of architectural modeling, however, the transition firing in object ....

R.G. Valk, "Petri Nets as Token Objects: An Introduction to Elementary Object Nets," Application and Theory of Petri Nets, J. Desel and M. Silva (eds.), LNCS 1420, pp. 1-25, 1998.

.... and Oliver describe a Petri net self modifying or reconfigurable net, which modifies its own structure by rewriting some of its components, but the reconfiguration information is not passed by the tokens [5] Similar ideas appear already in the work of Valk [25] Hierarchical networks: In [26, 18] hierarchical nets are studied in which tokens (objects) are nets as well, whose transitions may synchronize with the ones from the system net in which they travel. Although this approach is close to ours in a number of ways, it separates the behavior of the system net and the object net, and as ....

Rudiger Valk. Petri nets as token objects: An introduction to elementary object nets. In Jorg Desel and Manual Silva, editors, Application and Theory of Petri Nets, volume 1420 of Lecture Notes in Computer Science (LNCS), pages 1--25. Springer, 1989.

....are represented as classes. Keywords: Coloured Petri Nets, Design CPN, Net Skeletons, Net Generation, Object Orientation, Prototyping, Computer Tools 1 Introduction In our group the integration of object orientation and Petri nets is an ongoing topic (see [BM93] Mai96] Mol96] Val91] [Val98]) One major goal is to allow for the use of Petri nets as the means to execute object oriented speci cations. To achieve this a transformation of the models to Petri nets is necessary. In [Mol96] for several techniques transformation schemes were proposed, but no tool was presented at that time. ....

....computer aided implementation of ObjectOriented Coloured Petri nets as proposed by Moldt [Mol96] With respect to this aim other approaches to combine both the advantages of Object Orientation and Petri nets are not discussed here. For some work of object orientation and Petri nets see for example [SB94,Lak95,Val98,Mai96,Kum00,BG91,EMNW99,MM99]. Due to limited space the introduction of Petri nets in general and Coloured Petri nets in special is skipped here as well as the presentation of well known concepts of Object Orientation and techniquess like UML class diagrams. To become familiar with these concepts see for the study of Petri ....

Rudiger Valk. Petri Nets as Token Objects: An Introduction to Elementary Object Nets. In Jorg Desel, editor, 19th International Conference on Application and Theory of Petri nets, number 1420 in LNCS, Berlin, 1998. Springer-Verlag.

.... y address how similar representations could be de ned for other Petri net classes, such as colored Petri nets based on (higher order) programming languages [39] nets with macroplaces [2, 3] nets with FIFO places [30, 40, 29, 27] object oriented variants of Petri nets [68, 44] and object nets [73, 74, 28, 75] where nets are viewed as token objects. We conclude this introduction with a brief overview of the paper: After introducing rewriting logic together with the underlying membership equational logic in the following section, we introduce in Section 3 a category of place transition nets together ....

....logic has the advantage of being more general, in the sense that it goes beyond Petri net like models and hence provides a bridge to formalisms that are quite di erent from ordinary Petri nets. Yet another interesting generalization of Petri nets are di erent variants of object Petri nets [73, 74, 28, 75], where tokens can themselves be nets with their own dynamic behaviour. A quite di erent line of research is the integration of object oriented techniques with Petri nets. As a result there are a number of variants of object oriented Petri nets [68, 44] where the tokens are objects according to ....

R. Valk. Petri nets as token objects: An introduction to elementary object nets. In J. Desel and M. Silva, editors, Proceedings of the 19th International Conference on Application and Theory of Petri Nets, Lissabon, June 22-26,

....as token objects, di erent arc types, net instances, and communication via synchronous channels. Beside this they are very similar to coloured Petri nets as de ned by Jensen. The di erences now are shortly introduced. Nets as tokens Reference nets implement the nets within nets paradigm of Valk [15]. This paper follows his nomenclature and denominates the surrounding net system net and the token net object net. Certainly hierarchies of net within net relationships are permitted, so the denominators depend on the beholders viewpoint. Arc types In addition to the usual arc types reference ....

Rudiger Valk. Petri nets as token objects: An introduction to elementary object nets. In Jorg Desel and Manuel Silva, editors, Application and Theory of Petri Nets, volume 1420 of Lecture Notes in Computer Science, pages 1-25, June 1998.

....a detailed discussion in this manual. In directory 34 Figure 3.17: The net account samples fireman you can nd the reman example that is based on an idea of Petri [11] A work ow system of a law enforcement agency is the basis for the nets in samples prosecute. They are based on the article [14], where this example is attributed to W.M.P. van der Aalst. 3.8 Calling Nets from Java In the previous section we considered the use of a Java like inscription language in reference nets. Now we are going to allow access to reference nets from Java code. Nets are already objects and they have an ....

Rudiger Valk. Petri nets as token objects: An introduction to elementary object nets. In Jorg Desel and Manuel Silva, editors, Application and Theory of Petri Nets, volume 1420 of Lecture Notes in Computer Science, pages 1-25. Springer-Verlag, 1998.

....and the tokens are only references, as opposed to the value semantics, where the nets themselves reside on a place. This leads to the question, whether nets could be regarded as tokens and to the topic of self re exivity in the Petri net theory. The instrument of nets as tokens in a net of [Val98] de nes system nets which provide the environment for object nets to move and communicate. This idea is illustrated in Fig. 1, where one can see a system net having an object net as its token. The object net behaves like a token, so if the transition t 1 res it removes the object net from place s ....

....here is to use only one reference to a net to overcome this design problem. This is a special case of the approach in [K oh00] In this case value and reference semantics coincide. 2. 2 Reference Nets In this paper the formalism of reference nets is used which incorporates the concept of Valk in [Val98]. Reference nets as implemented by the Renew tool are a special high level Petri net formalism that provide dynamic creation of net instances, references to other net references as tokens, and communication via synchronous channels ( Kum98] Java is used as the inscription language. Basic ....

[Article contains additional citation context not shown here]

Rudiger Valk. Petri Nets as Token Objects: An Introduction to Elementary Object Nets. In Jorg Desel, editor, 19th International Conference on Application and Theory of Petri nets, number 1420 in LNCS, Berlin, 1998. Springer-Verlag.

.... For modelling and analysis distributed concurrent systems, there exists a large variety of formalisms based on Petri nets [Rei85,Jen92,Smi96,Lom97] Among them, several approaches extend the Petri nets formalism by notions and structures inspired from object oriented programming [Sib94,Lak95,MW97,Val98] Such extensions are helpful for modelling hierarchical multi agent distributed systems. While Sibertin Blanc [Sib94] Lakos [Lak95] Moldt and Wienberg [MW97] consider systems with communicating coloured Petri nets, Valk [Val98] in his object Petri nets considers tokens as objects with a net ....

....inspired from object oriented programming [Sib94,Lak95,MW97,Val98] Such extensions are helpful for modelling hierarchical multi agent distributed systems. While Sibertin Blanc [Sib94] Lakos [Lak95] Moldt and Wienberg [MW97] consider systems with communicating coloured Petri nets, Valk [Val98] in his object Petri nets considers tokens as objects with a net structure. In his approach, the system net and object nets are elementary net systems, but an object is in some sense not located in one place (since Valk uses object Petri nets for solving speci c fork join situations in task ....

R. Valk. Petri nets as token objects: An introduction to elementary object nets. In Proc. 19th Int. Conf. Application and Theory of Petri Nets, Lisbon, Portugal, June 1998, volume 1420 of Lecture Notes in Computer Science, pages 1-25. Springer, 1998.

....reference nets with Java expressions as arc and transition inscriptions. The resulting tool aims mainly at rapid prototyping and work ow applications. 1 Introduction This paper introduces and discusses reference nets, a net formalism that incorporates Valk s concept of nets as token objects [7], implements the idea of synchronous channels [1] allows to create net instances from net templates, and is closely related to Coloured Petri Nets. Compared to Valk s proposal, it will not be possible to copy or unify nets, but still nets can be referenced by tokens. Compared to ordinary ....

Rdiger Valk. Petri nets as token objects: An introduction to elementary object nets. In 19th Int. Conf. on Application and Theory of Petri Nets, volume 1420 of Lecture Notes in Computer Science, pages 125. Springer-Verlag, 1998.

....for the two problems identi ed. Reference nets are a class of Petri nets using the nets in nets paradigm [Val87] Using this paradigm tokens in the Petri net are represented by Petri nets. Many variants of such an approach have been proposed [Lak95,Hol95,Val87] In the notion of object nets [Val98], tokens of a so called system net correspond to marked Petri nets on a lower level, called object nets. Since the object nets actually reside in the system net, we call this the valuesemantics approach. Reference nets use another approach: The object nets do not actually reside in the system net, ....

Rudiger Valk. Petri Nets as Token Objects: An Introduction to Elementary Object Nets. In Jorg Desel, editor, #### ############# ########## ## ########### ### ###### ## ##### ####, number 1420 in LNCS, Berlin, 1998. Springer-Verlag.

....clearly more general, as a topological structure of the system net is not necessarily assumed. As in preceding papers we restrict both net types to elementary net systems and call them Elementary Object Nets (EOS) They have been studied as task systems in earlier papers ( Val87a] Val87b] In ([Val98], Val99b] applications to the modeling of work flow and flexible manufacturing system are given. In the latter case the system net models the environment of machines, robots, conveyors etc. whereas the object nets are execution plans containing the current state of processing. The papers ....

....consist of a reference to a single object 9 net, whereas in value semantics these instances of the object net are considered as independent copies. The copies are identical in their net structure but may di#er in their current marking. Reference semantics has been formalized as bi markings in [Val98] and [Val99b] It is also the leading paradigm of reference nets as introduced in [Kum98] or as implemented in the Renew tool [KW99] Value semantics was used when working with process markings (p markings) in [Val98] and [Val99b] Recently a di#erent formalization using Linear Logic is given in ....

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R. Valk. Petri Nets as Token Objects - An Introduction to Elementary Object Nets. In J. Desel and M. Silva, editors, Application and Theory of Petri Nets, number 1420 in LNCS, pages 1--25, Berlin, 1998. Springer-Verlag.

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Valk, R., Petri nets as token objects: An introduction to elementary object nets, in: J. Desel and M. Silva, editors, 19th International Conference on Application and Theory of Petri Nets (1998), pp. 1--25.

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R. Valk. Petri nets as token objects: An introduction to elementary object nets. In J. Desel and M. Silva, editors, 19th International Conference on Application and Theory of Petri Nets, pages 1--25, Lisbon, Portugal, 1998. Springer-Verlag LNCS 1420.

No context found.

R. Valk. Petri Nets as Token Objects: An Introduction to Elementary Object Nets. In J. Desel and M. Silva, editors, ry o Petri Nets 1998, Co3R88fl Science, pages 1--25. Springer-Verlag, Berlin, 1998.

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