## Actors and their Composition (2002)

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Venue: | Formal Aspects of Computing |

Citations: | 4 - 2 self |

### BibTeX

@TECHREPORT{Janneck02actorsand,

author = {Jörn W. Janneck and Jörn W. Janneck},

title = {Actors and their Composition},

institution = {Formal Aspects of Computing},

year = {2002}

}

### OpenURL

### Abstract

Modern environments for modeling and designing concurrent computational systems increasingly support heterogeneous system models, which are characterized by different coordination mechanisms governing the interaction between concurrent components in different parts or at different levels of the model. These interaction semantics, also called models of computation, pose a major challenge to the definition of the meaning of heterogeneous models, especially if such a definition is to be independent of any specific set of models of computation, ways of describing actors, or notations for describing models.

### Citations

2208 | Statecharts: a visual formalism for complex systems
- Harel
- 1987
(Show Context)
Citation Context ...ple discrete event (DE) model. It contains the model in Fig. 1 as the actor labeled A. interactions to a small number of predefined models of computation—e.g., systems such as SDL [GK97], StateChart=-=s [Har87]-=-, or Polis [BGJ + 97] make the globally asynchronous, locally synchronous (GALS) assumption, i.e. systems modeled in these languages consist of asynchronously communicating components that function in... |

1132 | Actors: a model of concurrent computation in distributed systems - Agha - 1986 |

878 | Virtual time
- Jefferson
- 1985
(Show Context)
Citation Context ...o be dead. As an example, consider a composition that allows for rollback of the component actors (as might be the case, e.g., for a model of computation that realizes a protocol similar to Time Warp =-=[Jef85]). Say, in a step �-=-� ✲ σ τ ′ of the composite, a component actor Av would make a step σv ✲ σ τv ′ v. If the step of the component might be rolled back, the decomposition morphism φv = 〈sv, tv〉 must hav... |

832 |
The semantics of a simple language for parallel programming
- Kahn
- 1974
(Show Context)
Citation Context ...senders and receivers beyond the component boundaries. As a somewhat related abstraction, Kahn introduced process networks as a model of computation for describing compositions of parallel processes. =-=[Kah74]-=- Processes in this model could formally be interpreted as functions on potentially infinite streams of data. Apart from the fact that these networks guaranteed determinacy under some simple conditions... |

506 | Synchronous data flow
- Lee, Messerschmitt
- 1987
(Show Context)
Citation Context ...uilding blocks, called actors (we will discuss them in a little more detail in section 2), which interact with each other according to the rules of the synchronous dataflow (SDF) model of computation =-=[LM87]-=-. For example, the components consume and produce a constant number of data items (tokens) each time they are activated (in the case of this model, precisely one at each input and output port), and th... |

415 |
Viewing control structures as patterns of passing messages
- Hewitt
- 1977
(Show Context)
Citation Context ...ch as, e.g., debugging compositions at runtime. 7. Related work Actor-based models for concurrent systems have a long tradition. The original use of the term in this context is probably due to Hewitt =-=[Hew77]-=-, founding a rich area of research. [Agh86, AMST93] In this model, actors are themselves sequential entities, communicating with each other via message passing. In the original model, actors had to kn... |

281 | Dataflow Process Networks
- Lee, Parks
- 1995
(Show Context)
Citation Context ...tatic analysis resulting in more assurances about the system behavior and possibly more efficient implementations—such as e.g. synchronous dataflow [LM87] and cyclo-static dataflow [EBLP94]. See als=-=o [Lee94]-=- for an overview. Dennis introduced a dataflow language that was built on a notion of firing, i.e. an atomic step where a component would consume and produce a finite amount of data. [Lee97] showed ho... |

261 | A framework for comparing models of computation
- Lee, Sangiovanni-Vincentelli
- 1998
(Show Context)
Citation Context ...ess the composition of actor firings. The bewildering variety of ways in which conceptually concurrent processes/tasks/actors etc. can bes20 Jörn W. Janneck composed gave rise to the work reported in=-= [LSV98]-=-, which presents a denotational framework in which a large number of so-called models of computation can be represented and compared to each other. Models of computation in this context are mathematic... |

227 | A foundation for actor computation - Agha, Mason, et al. - 1997 |

214 | The foundations of Esterel
- Berry
- 2000
(Show Context)
Citation Context ...n these languages consist of asynchronously communicating components that function internally in a synchronous fashion. Other approaches, such as synchronous languages like Signal [ABG95] and Esterel =-=[Ber00], -=-allow only one kind of interaction—resulting in tools which are often ideally suited to a particular application area, but perform poorly at representing more heterogeneous systems, and say little a... |

105 | Taming Heterogeneity—The Ptolemy Approach - Eker, Janneck, et al. - 2003 |

44 |
Interaction semantics for components of distributed systems
- Talcott
- 1996
(Show Context)
Citation Context ...In this model, actors are themselves sequential entities, communicating with each other via message passing. In the original model, actors had to know the receiver of a message they intended to send. =-=[Tal96]-=- introduces a more compositional model for actor-based systems, where components are networks of actors that are connected with what effectively amounts to ports, i.e. abstractions for senders and rec... |

26 | A denotaional semantics for dataflow with firing
- Lee
- 1997
(Show Context)
Citation Context ...anguage, semantics). We will call a set L of well-formed programs denoting actors an actor language, and a function [·] : L −→ A its semantics. Our actors are generalizations of the ones describe=-=d in [Lee97] in sev-=-eral ways. First of all, they have state. Second, they allow non-determinism, i.e. given a state σ and an input tuple s, there may be multiple output tuples s ′ and s ′′ and/or multiple success... |

22 |
Compositional modeling in metropolis
- Goessler, Sangiovanni-Vincentelli
(Show Context)
Citation Context ...in the kinds of component interactions, or the ways in which they are combined with each other. Examples of this kind of modeling environment would be Ptolemy [DHK + 01], Moses [EJ01], and Metropolis =-=[GSV02]-=-. We assume that models are hierarchically structured, such that parts modeled in different models of computation are nested within each other. This way of structuring heterogeneous models is called h... |

21 |
Cyclostatic dataflow: Model and implementation
- Engels, Bilsen, et al.
- 1994
(Show Context)
Citation Context ...ed more extensive static analysis resulting in more assurances about the system behavior and possibly more efficient implementations—such as e.g. synchronous dataflow [LM87] and cyclo-static dataflo=-=w [EBLP94]-=-. See also [Lee94] for an overview. Dennis introduced a dataflow language that was built on a notion of firing, i.e. an atomic step where a component would consume and produce a finite amount of data.... |

19 |
Moses: A tool suite for visual modeling of discrete-event systems
- Esser, Janneck
- 2001
(Show Context)
Citation Context ...es not a priori constrain the kinds of component interactions, or the ways in which they are combined with each other. Examples of this kind of modeling environment would be Ptolemy [DHK + 01], Moses =-=[EJ01]-=-, and Metropolis [GSV02]. We assume that models are hierarchically structured, such that parts modeled in different models of computation are nested within each other. This way of structuring heteroge... |

13 | Abstract state machine semantics of SDL
- Glässer, Karges
- 1997
(Show Context)
Citation Context ...eEvent Fig. 2. A simple discrete event (DE) model. It contains the model in Fig. 1 as the actor labeled A. interactions to a small number of predefined models of computation—e.g., systems such as SD=-=L [GK97]-=-, StateCharts [Har87], or Polis [BGJ + 97] make the globally asynchronous, locally synchronous (GALS) assumption, i.e. systems modeled in these languages consist of asynchronously communicating compon... |

11 | Heterogeneous concurrent modeling and design - Hylands, Kienhuis, et al. - 2001 |

6 | A predicate-based approach to defining visual language syntax
- Janneck, Esser
(Show Context)
Citation Context ..., σ ′ , s ′ ) ∈ τ n . For any n ∈ N, τ n is the smallest set such that: ∃σ ′′ : σ u↦→u′ τ n−1 ✲ σ ′′ ∧ σ σ λ↦→λ τ 0 ✲ σ for all σ ∈ Σ s↦→s′ �=-=��′ τ ✲ σ ′ =⇒ σ us↦→u′ s ′ τ n ✲ σ ′ for n > 0 6 See, e.g., [JE01] for some disc-=-ussion of these issues for visual modeling languages.sActors and their composition 11 The set τ ∗ =def n∈N We call the actor � τ n is the union of all finite iterations of τ. A ∗ =def 〈σ... |

5 |
Syntax and Semantics of Graphs—An approach to the specification of visual notations for discrete event systems
- Janneck
- 2000
(Show Context)
Citation Context ...ing a stream function, thereby effectively unifying Kahn process networks and Dennis dataflow. One remaining problem was the composition of the notion of firing, and the way it interacted with state. =-=[Jan00]-=- provided a more general treatment of state, though it did not address the composition of actor firings. The bewildering variety of ways in which conceptually concurrent processes/tasks/actors etc. ca... |

4 |
Loïc Besnard, and Paul Le Guernic. Implementation of the dataflow synchronous language SIGNAL
- Amagbégnon
- 1995
(Show Context)
Citation Context ...e. systems modeled in these languages consist of asynchronously communicating components that function internally in a synchronous fashion. Other approaches, such as synchronous languages like Signal =-=[ABG95] a-=-nd Esterel [Ber00], allow only one kind of interaction—resulting in tools which are often ideally suited to a particular application area, but perform poorly at representing more heterogeneous syste... |

1 |
Caltrop—language report
- Eker, Janneck
- 2002
(Show Context)
Citation Context ... inputs to outputs, it follows that the set of actors is uncountably large, and that therefore not all actors can be represented in the language. 13 These are only limitations of our toy language—Ca=-=l [EJ02]-=- allows actors to express much more sophisticated patterns of token consumption.sActors and their composition 19 A well-designed actor language provides constructs that allow to express these kinds of... |