J.D. Brock, W.B. Ackerman. Scenarios: A Model of Non-Determinate Computation. In J. Dia, I. Ramos (editors) Formalization of Programming Concepts, Lect. Notes in Comp. Sci. 107, pp. 252--259, Springer-Verlag, 1981.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....have e.g. #.#.## #.#.#)# = ##.#.#.#.##. A trace operation to represent dataflow processes with feedback loops is not definable in AL, because then we would have obtained a compositional relational semantics of nondeterministic dataflow with feedback, shown impossible by Brock and Ackerman [9]. However, with a more refined notion of relation in which the input and output of a dataflow process may be related in di#erent ways, such a semantics is in fact possible [23] 26 6 Related Work We conclude by setting the specific results of this paper in the context of what we see as a ....

J. D. Brock and W. B. Ackerman. Scenarios: a model of non-determinate computation. In Proc. Formalization of Programming Concepts 1981, LNCS 107.

....(in general) represent the process s behavior exactly; generally, the input output function must be a conservative approximation. One way to remedy this would be to augment MFGs with a partial ordering that can express inter channel orderings; this is reminiscent of Brock and Ackermann s scenarios [BA81, Bro83] and Pratt s model of processes [Pra82] 19 5.3 Infinite Executions Multiplicities are defined to represent subsets of the natural numbers, so they can represent unbounded but not infinite sequences. One approach to analyzing systems with infinite executions is to generalize multiplicities ....

J. Dean Brock and William B. Ackerman. Scenarios: A model of non-determinate computation. In J. Diaz and I. Ramos, editors, Formalisation of Programming Concepts, volume 107 of Lecture Notes in Computer Science, pages 252--259. Springer-Verlag, 1981.

....not definable in the present affinelinear language. It can be shown that if the trace operation of [9] were definable in the presheaf semantics, we could obtain (replacing Set by 2) a compositional relational semantics of nondeterministic dataflow with feedback, shown impossible by Brock Ackerman [3]. 6. Operational semantics We now consider the tensor fragment of the affine linear language, the fragment obtained by leaving out product (for brevity) and function space (in progress) We employ the language of general patterns of Section 4. It can be given semantics using judgements of the ....

J. Brock and W. Ackerman. Scenarios: A model of nondeterminate computation. In Proc. of Formalization of Programming Concepts. LNCS 107, 1981.

....representing processes with nondeterministic behavior. Nondeterministic Process Nets There have been several attempts to generalize the stream processing model of Kahn and MacQueen to incorporate nondeterminism. One such attempt is reported by Brock in [Brock83] superseding the earlier version [Brock81] by Brock and Ackermann) where references to other attempts are given. In [Brock83] it is shown that the straightforward attempt to generalize the model of Kahn and MacQueen by permitting process behaviors to be relations, rather than functions, is doomed to failure. Intuitively, the reason is ....

Brock, J.D., Ackermann, W.B., "Scenarios: A Model of Non-determinate Computation," Proc. Peniscola Colloquim, Springer LNCS 107, 1981.

....behaviour is taken to be the input output relation between completed sequences of values, thus it completely abstracts away from causal dependencies between values on different ports. 2.1 The need for causality For indeterminate networks, the situation is not so simple. Brock and Ackerman[6] showed that for networks containing the nondeterministic primitive fair merge, the input output relations are not compositional, i.e. if we simply choose the inputoutput relation as observable behaviour, we cannot define a compositional semantics, which is adequate with respect to the operational ....

BROCK, J., AND ACKERMAN, W. Scenarios: a model of non-determinate computation. In Formalization of Programming Concepts (1981), Diaz and Ramos, Eds., vol. 107 of LNCS, Springer.

....Kahn s semantics somehow marks a border between when the behaviour of dataflow systems can be described compositionally purely by its input output relation between a domain of input values and a domain of output values and when a more detailed mathematical model is required. Brock and Ackerman [17] proved that if the nondeterministic primitive fair merge was added to the calculus it was no longer possibly to give a compositional semantics in the history model. As we recall in Sec. 8.1.1 Russell [116] later showed that the history model is insu#cient also if just the simpler [102] primitive ....

.... event structure and traces based models to the relational model, following the pattern set in [146] The higher order models should be compared to the work in [4] It would be very interesting to compare the abstract profunctor model to the more concrete models of scenarios (Brock and Ackerman [17, 16]) A comparison with the semantics in [123] which unfortunately just recently have come to our attention, should also be carried out. Early attempts have been made to incorporate fairness into the calculus sketched above and the profunctor model. It is hoped to exploit independence along the ....

[Article contains additional citation context not shown here]

J.D. Brock and W.B. Ackerman. Scenarios: A model of non-determinate computation. In J. Diaz and I Ramos, editors, Formalization of Programming Concepts, volume 107 of LNCS. Springer, 1981.

....on the systems but on the mode of observation. Observations may include multiple interactions with the system, with one of several pragmatics [GW] on line vs. o line, leading to distinctions known in process theory as linear time vs. branching time equivalence [Pn] The Brock Ackerman anomaly [BA] is a classic example of how these modes of observation a ect the observer s ability to distinguish between systems. 1 black box vs. glass box, known in process theory as as trace equivalence vs. di erent types of simulation. The equivalence classes of system behavior induced by di erent ....

J.D. Brock, W.B. Ackerman. Scenarios: A Model of Non-Determinate Computation, pp. 252-259. LNCS, Springer-Verlag, 1981.

....of transformations the key to correctness by construction. The transformations assure the local correctness from which global correctness can be concluded because of compositionality. Allowing non determinism can cause problems with compositionality as shown by the Brock Ackerman anomaly [Bro81]. Therefore, compositionality should be defined and checked carefully. Compositionality in general is a property of a function with respect to two composition operators, one on the domain of the function and one on its codomain. In case of compositionality the function value of a composition ....

J.D. Brock and W.B. Ackerman, Scenarios:A Model of Nondeterminate computation, in J. Diaz and I. Ramos(eds), Formalization of Programming concepts, LNCS 107, pp 252259, Springer Verlag, 1981.

....input and output messages. The extension of deterministic data flow networks to nondeterministic data flow networks proves, however, to be a nontrivial task. In the history based approach, the replacement of functions with input output relations leads to a non compositional model, as shown in [BA81]. The replacement of functions with sets of functions, leads to a compositional model which is however too restrictive, because as shown in [Kel78] it cannot express nondeterministic fair merge components. In the statebased approach, there is no obvious way how to compose automata. One attempt is ....

J. D. Brock and W. B. Ackermann. Scenarios: A model of non-determinate computation. In Proc. Formalization of Programming Concepts, Lecture Notes in Computer Science 107, pages 252--259, 1981.

....different notion of observation. This allows us to describe a considerably greater class of networks. In particular, we can describe unbounded nondeterministic networks. Moreover, since our model is fully abstract, we obviously avoid the expressiveness problem known as the Brock Ackermann anomaly [BA81]. Secondly, contrary to Kahn, we describe dynamically reconfigurable or mobile networks networks in which every component may change its communication partners on the basis of computation and interaction. The formal modeling of mobility has been a very popular research direction in recent ....

J. D. Brock and W. B. Ackermann. Scenarios: A model of non-determinate computation. In Proc. Formalization of Programming Concepts, Lecture Notes in Computer Science 107, pages 252--259, 1981.

....the implementability of relations by a certain class of mechanisms; they are not directly concerned with the definability of relations purely in terms of other relations. Indeed, a satisfactory abstract notion of definability of relations is not really possible; for example Brock and Ackerman [7] show that one can have two processes with the same IO relation but which behave differently in the same context. Thus one really is forced to work with some more concrete description. Jonsson has shown [14] that traces are fully abstract for dataflow networks so one can use traces to establish ....

....than fair merge, even in combination with amerge. Even more surprising is the fact, discovered by the second author, that amerge can implement imerge; the details are a little tricky but not deep. In view of the fact that relations do not yield a compositional semantics, the BrockAckerman anomaly [7], and the fact that traces are in fact the fully abstract model for dataflow networks one can consider the relation between automata and traces. One can work directly with traces and define processes as traces sets. Using this point of view, Panangaden and Shanbhogue [24] showed that angelic merge ....

J. Dean Brock and W. B. Ackerman. Scenarios: A model of non-determinate computation. In J. Diaz and I. Ramos, editors, International Colloquium on Formalization of Programming Concepts, pages 252--259. Springer-Verlag, 1981. Lecture Notes In Computer Science 107.

No context found.

J.D. Brock, W.B. Ackerman. Scenarios: A Model of Non-Determinate Computation. In J. Dia, I. Ramos (editors) Formalization of Programming Concepts, Lect. Notes in Comp. Sci. 107, pp. 252--259, Springer-Verlag, 1981.

No context found.

J. Dean Brock and William B. Ackerman. Scenarios: A model of nondeterminate computation. In J. Diaz and I. Ramos, editors, Formalism of Programming Concepts, volume 107 of Lecture Notes in Computer Science, pages 252--259. Springer Verlag, 1981.

No context found.

J. Brock and W. Ackerman. Scenarios: A model of non-determinate computation. In J. Daz and I. Ramos, editors, Formalization of Programming Concepts, International Colloquium, Peniscola, Spain, April 19-25, 1981.

No context found.

J. Dean Brock and William B. Ackerman. Scenarios: a model of nondeterminate computation. In Diaz and Ramos, editors, Formalization of Programming Concepts, LNCS 107, volume 107 of Lecture Notes in Computer Science, pages 252--259. Springer-Verlag, 1981.

No context found.

J. D. Brock and W. B. Ackermann. Scenarios: A model of nondeterminate computation. In J. Diaz and I. Ramos, editors, Formalization of programming concepts, LNCS 107, pages 225--259. Springer.

No context found.

J. D. Brock and W. B. Ackerman. Scenarios: a model of nondeterminate computation. In Proc. Formalization of Programming Concepts 1981, LNCS 107.

No context found.

J. D. Brock and W. B. Ackermann. Scenarios: A model of non-determinate computation. In Proc. Formalization of Programming Concepts, Lecture Notes in Computer Science10fi , pages252--2592 192--2 [BD922 M. Broy and C. Dendorfer. Modelling operating system structures by timed stream processing functions. Journal of Functional Programming, 2:1--21, 192

No context found.

Brock, J. D., Ackermann, W. B.: Scenarios: A Model of Non-determinate Computation. Proc. Formalization of Programming Concepts, LNCS 107, (1981) 252-259

No context found.

J. D. Brock and W. B. Ackerman. Scenarios: a model of non-determinate computation. In Proc. Formalization of Programming Concepts 1981, LNCS 107.

No context found.

J. D. Brock and W. B. Ackerman. Scenarios: a model of nondeterminate computation. In Proc. Formalization of Programming Concepts 1981, LNCS 107.

No context found.

J. D. Brock and W. B. Ackermann. Scenarios: A model of non-determinate computation. In J. Diaz and I. Ramos, editors, Proc. Formalization of Programming Concepts, Lecture Notes in Computer Science 107, pages2fles; 1981.

No context found.

J. Brock and W. Ackerman. Scenarios: a model of non-determinate computation. In Forrealization of Programming Concepts, LNCS I07, pages 252-259. 1981.

No context found.

, 4, pp. 727--767, 1986. Brock, J. D., and W. B. Ackerman, "Scenarios: a model of nondeterminate computation," in Formalization of Programming Concepts (eds. J. Diaz and I. Ramos), Lecture Notes in Computer Science,

No context found.

Brock J.D., Ackerman W.B. Scenarios: A model of non-determinate computation. In Formalization of Programming Concepts, Volume 107 of Lecture Notes in Computer Science, Springer-Verlag, 1981.

First 50 documents  Next 50

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC