Gerard Boudol. Some chemical abstract machines. In A Decade of Concurrency, volume 803 of LNCS, pages 92--123. Springer-Verlag, 1994.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....tokens. However, rules are not supposed to travel in their model which aims at modeling passive networking protocols. Another abstract model based on a pool of molecules is Ban atre and Le M etayer s chemical abstract machine (CHAM) It will be interesting to follow the study of such systems [4], especially as they attempt to bridge calculus style reasoning with the family of caluli. Milner s calculus [16] was among the first to address mobility in a formal way. Salient feature of this calculus are names which are used to identify communication channels and which can be sent along ....

G. Boudol, Some Chemical Abstract Machines, In A Decade of Concurrency, LNCS 803, May 1994.

....1993] The CHAM formalism provides a powerful set of primitives for computational modeling. Indeed, its generality, power, and utility have been clearly demonstrated by its use in formally capturing the semantics of familiar computational models such as the # calculus and the CCS process calculus. Boudol [1994] points out that the CHAM formalism has also been demonstrated as a modeling tool for concurrent language definition and implementation. A CHAM is specified by defining molecules m 1 , m 2 , defined as terms of a syntactic algebra that derive from a set of constants and a set of operations, ....

BOUDOL, G. 1994. Some Chemical Abstract Machines. In A Decade of Concurrency, Number 803 in Lecture Notes in Computer Science (May 1994), pp. 92--123. Springer-Verlag.

....ffl Preconditions containing relational operators are encoded as conditions, whereas the molecule corresponding to the variable is deleted and added again, as already described. This conforms to the chemical semantics where conditions can only be stated on local molecules involved in a rule [4]. It is possible to define many other functions to describe, for instance, when rules, namely operation schemas, can fire concurrently: it usually depends on their postconditions. 1 A similar function has been defined for initialization operation, where no preconditions are present. 3 2.1 The ....

G. Boudol. Some Chemical Abstract Machines. In J. deBakker, W. deRoever, and G. Rozenberg, editors, A Decade of Concurrency, volume 803 of Lecture Notes in Computer Science, pages 92--123. Springer-Verlag, Berlin, 1993.

....solutions can evolve freely in any molecule context: S S 0 fjC[S]jg fjC[S 0 ]jg (2) These two rules are the only rules that involve an induction on the behaviour of a solution S: Every other rule is purely local, i.e. it will only concern the molecules participating in a reaction. In [7], the reaction rules S S 0 are classi ed into two kinds, formalising the transition relation as two binary relations over multisets and 7 . Intuitively, transitions S 7 S 0 represent proper reactions changing the solution on the left hand side permanently to the solution on the ....

....if nodes are added to or deleted from a network. Also, higher concepts in CHAMs as, for instance, the airlock operator from [6] have to be examined. With respect to this operator, it is planned to look at a relation between the CHAMs we presented and models for process algebras as given in [6, 7] to generate simulation models from local observations. Acknowledgements The presented work has been supported by Siemens Switzerland. The authors would like to thank Dieter Hogrefe (ITM L ubeck) for supporting this work, Iwan Nussbaumer and Charles Zehnder (Siemens Switzerland) for many ....

Boudol, G.: Some Chemical Abstract Machines. In A Decade of Concurrency, number 803 in Lecture Notes in Computer Science, pp. 92-123. Springer-Verlag, May 1994.

....The CHAM formalism provides a powerful set of primitives for computational modeling. Indeed, its generality, power, and utility have been clearly demonstrated by its use in formally capturing the semantics of familiar computational models such as the calculus and the CCS process calculus. Boudol [6] points out that the CHAM formalism has also been demonstrated as a modeling tool for concurrent language de nition and implementation. A CHAM is speci ed by de ning molecules m 1 ; m 2 ; de ned as terms of a syntactic algebra that derive from a set of constants and a set of operations, and ....

G. Boudol. Some Chemical Abstract Machines. In A Decade of Concurrency, number 803 in Lecture Notes in Computer Science, pages 92-123. Springer-Verlag, May 1994.

....where all transmitted vectors of names have length one. In the monadic calculus, we assume that all names have a sort s satisfying the recursive equation s = Ch(s) By analogy with the untyped calculus, we call this the unsorted monadic 1 calculus. We observe that the translation presented in [Bou93] from the polyadic to the monadic asynchronous calculus can be typed in our framework. We outline the translation in gure 4. Note that there are more rened sorting disciplines which can be dened on the monadic calculus, and in which we can still sort the translation above. One obvious solution, ....

G. Boudol. Some chemical abstract machines. In Springer Lect. Notes in Comp. Sci. 803: Proceedings of REX School. Springer-Verlag, 1993.

....systems, offering a specifier two complementary approaches to validate and test a specification. In addition to the abstract, declarative semantics given in [13] we introduce a new operational semantics based on the chemical metaphor embedded in the notation of the Chemical Abstract Machine [1]. On such a semantics we define a Unity like logic offering a number of constructs which can be used to define and analyze dynamic properties. In addition we offer a parallel animator which automatically generates a distributed prototype of the system. The tool is a parallel animator: it consists ....

....first operation applied is the initialization operation without any preconditions. From every node there can be several different applicable operation sets. Each branch of the tree corresponds to the application of a group of enabled operations which do not conflict, as dictated by the CHAM model [1]. Every node is labeled with (s; seq) where s is an instance of a state schema and seq is a sequence of operations sets. The chemical interpretation imposes that for every node: all operations in the sets belonging to the sequence seq must be enabled on s and must act on the state schema of ....

G. Boudol. Some Chemical Abstract Machines. In J. deBakker, W. deRoever, and G. Rozenberg, editors, A Decade of Concurrency, volume 803 of Lecture Notes in Computer Science, pages 92--123. Springer-Verlag, Berlin, 1993.

....The CHAM formalism provides a powerful set of primitives for computational modeling. Indeed, its generality, power, and utility have been clearly demonstrated by its use in formally capturing the semantics of familiar computational models such as CSP [13] and the CCS process calculus [17] Boudol [6] points out that the CHAM formalism has also been demonstrated as a modeling tool for concurrent language definition and implementation. A CHAM is specified by defining molecules m,m # , defined as terms of a syntactic algebra that derive from a set of constants and a set of operations, and ....

G. Boudol. Some Chemical Abstract Machines. In A Decade of Concurrency, number 803 in Lecture Notes in Computer Science, pages 92--123. Springer-Verlag, May 1994.

....provides a powerful set of primitives for computational modeling. Indeed, its generality, power, and utility have been clearly demonstrated by its use in formally capturing the semantics of older, more familiar computational models, such as CSP [13] and the CCS process calculus [20] Boudol [6] points out that the CHAM formalism has also been demonstrated as a modeling tool for concurrent language de#nition and implementation. Inverardi and Wolf [14] developed a framework for architectural speci#cation and analysis based on the CHAM formalism. Their goal is to apply the power of the ....

G. Boudol, Some chemical abstract machines, in: A Decade of Concurrency, Lecture Notes in Computer Science, Vol. 803, Springer, Berlin, 1994, pp. 92--123.

....synchronisation of calculus by introducing a more asynchronous calculus separated by a synchroniser. This calculus, which is called commutative calculus ( c for short) allows communication by a process under prefix if there is no binding. We define c calculus following the ideas in [8] and [33] It is notable that c calculus is not a subsystem of calculus because of additional structural rules; this makes direct comparison of its expressiveness difficult. But we can prove that c calculus has less power than the asynchronous calculus by using the combinators again. ....

....j by:ax:P (x 6= b; y 6= a) 23 We denote P c for the set of c terms. Gamma is defined in the same way as in the asynchronous calculus and l Gamma is given in Appendix A.3. Then we write c for a weak bisimilarity for c calculus. 10 The first structural rule (1) is found in [8], while the second one (2) comes from [33] Notice that in any strong and weak semantics, we have ax:by:P 6 by:ax:P in calculus. An example of reduction of c calculus (with x 6= a and b 6= y) is: av j bx:ay:aw j av j ax:by:aw (by (2) in Definition 4.10) j av j ax:by: 0 j aw) by P j 0 j P ....

[Article contains additional citation context not shown here]

Boudol, G., Some chemical abstract machines, Proceedings of the REX School/Workshop "A Decade of Concurrency", LNCS 803, pp.92--123, 1994.

....studies synchronisation of calculus by introducing a more asynchronous calculus separated by a synchroniser. This calculus, which is called commutative calculus ( c for short) allows communication by a process under prefix if there is no binding. We define c calculus following the ideas in [7] and [20] It is notable that c calculus is not a subsystem of calculus because of additional structural rules; this makes direct comparison of its expressiveness difficult. But we can prove that c calculus has less power than calculus by using the combinators again. Definition 4.4. ....

....the same syntax as in 2.1 for the syntax of c calculus and add the following two laws as new structural rules. ax: P j Q) j ax:P j Q (x 62 fn(Q) and ax:by:P j by:ax:P (x 6= b; y 6= a) Gamma is defined modulo j in the same way as in calculus (cf. 34] The first structural rule is found in [7], while the second one comes from synchronous calculus in [20] Notice that in any strong and weak semantics, we have ax:by:P 6 by:ax:P in calculus. An example of reduction of c calculus (with x 6= a and b 6= y) is: av j bx:ay:aw j av j ax:by:aw j av j ax:by:0 j aw Gamma av j by:0 It ....

Boudol, G., Some chemical abstract machines, Proceedings of the REX School/Workshop "A Decade of Concurrency", LNCS 803, pp.92--123, 1994.

....This subsection studies synchronisation by introducing a more asynchronous calculus separated by a synchroniser. This calculus, which is called commutative calculus ( c for short) allows commutation of prefixes if there is no ordering by binding. We define c calculus following the ideas in [8] and [24] It is notable that c calculus is not a subsystem of calculus because of additional structural rules; this makes direct comparison of its expressiveness difficult. But we can prove that c calculus has less power than the asynchronous calculus by using the combinators again. ....

....use the same syntax as in 2.1 for the syntax of c calculus and add the following two laws as new structural rules. ax: P j Q) j ax:P j Q (x 62 fn(Q) and ax:by:P j by:ax:P (x 6= b; y 6= a) Gamma is defined modulo j in the same way as in [22] cf. 41] The first structural rule is found in [8], while the second one comes from [24] Notice that in any strong weak asynchronous synchronous semantics, we have ax:by:P 6 by:ax:P . An example of reduction of c calculus (with x 6= a and b 6= y) is: av j bx:ay:aw j av j ax:by:aw j av j ax:by:0 j aw Gamma av j by:0 It seems impossible to ....

Boudol, G., Some chemical abstract machines, Proceedings of the REX School/Workshop "A Decade of Concurrency", LNCS 803, pp.92--123, 1994.

....of the operational semantics of this system which can be characterized by the way they represent sharing. The models of Jeffrey [Jef93, Jef94] and Launchbury [Lau93] use a single global environment in which all shared nodes are placed. The models of Ariola et al. AFM 95] and Boudol [Bou93] use multiple local environments in a similar way to the explicit substitutions calculus of Abadi et al. ACCL90] Here we will use a variant of the model presented by Launchbury, as the global environment models are closer to the model used in an implementation, and are also easier to use when ....

G'erard Boudol. Some chemical abstract machines. In A Decade of Concurrency---Reflections and Perspectives, Proceedings of the REX School Symposium, volume 803 of Lecture Notes in Computer Science, pages 92--123, Berlin, Germany, June 1993. Springer-Verlag.

....without preconditions. 3 Operational semantics The standard Z semantics [17, 4] does not offer formalization for concurrency. Thus, we have defined a new operational semantics based on the concurrency offered by the chemical model. 3. 1 The chemical metaphor In the Chemical Abstract Machine model [2, 3] Molecules, Solutions, and Rules are the fundamental elements. A Chemical Abstract Machine is a triple (G ; C ; R) where G is a grammar, C is a set of configurations (the language generated by the grammar) or molecules, and R is a set of the rules condition(C ) Theta bag C Theta bag C . A ....

....molecule) We remark that Z sets and bags are decomposed by this function in several molecules to increase potential concurrency. Fsem op associates a rule to an operation schema 2 : 2 A similar function can be defined for the initialization operation, where no preconditions are present [3]. Fsem op : SCHEMA OP RULE Fsem op associates to pre and postcondition different part of the rule: Every Z schema postcondition that specifies the removal of an element from a set or bag is mapped on a pretuple of the rule (molecule to be deleted) Every postcondition that specifies ....

[Article contains additional citation context not shown here]

G. Boudol. Some Chemical Abstract Machines. In J. deBakker, W. deRoever, and G. Rozenberg, editors, A Decade of Concurrency, volume 803 of Lecture Notes in Computer Science, pages 92--123. Springer-Verlag, Berlin, 1993.

....THE CHEMICAL ABSTRACT MACHINE MODEL 375 consume elements of the multiset and produce new ones according to the rules that constitute the program. Since reactions on disjoint subsets can take place in any order or even simultaneously, the model is inherently parallel. It has been pointed out [5] [6] that Petri nets are a well known example of the multiset transformation style of programming, where markings are multisets of places and each transition of the net can be seen as a reaction rule to transform the markings. Hence, there is already a large body of experience with this kind of ....

....ourselves to only those concepts directly required for this paper. The interested reader is referred elsewhere [5] for a complete description of the model and examples of its use in formally capturing the semantics of older, more familiar models, such as the CCS process calculus [12] Boudol [6] mentions that the CHAM has also been demonstrated as a modeling tool in other areas, from graph reduction to concurrent language definition and implementation. In sections IV and V, we introduce the CHAM into the domain of software architecture specification and analysis. A. Basics A Chemical ....

G. Boudol. Some Chemical Abstract Machines. In A Decade of Concurrency, number 803 in Lecture Notes in Computer Science, pages 92--123. Springer-Verlag, May 1994.

....that receives only once on a channel. We can use this abbreviation in the translation into an unsorted monadic 1 calculus. In the unsorted monadic 1 calculus all names have a sort s satisfying the recursive equation s = Ch(s) Thus, all channels carry exactly one name of sort s. Following [13], the kernel of the translation is presented below. We note that these processes can be easily typed in our framework. hab 1 ; b n i = c (ac j c(d) db 1 j Delta Delta Delta j c(d) db n Gamma1 j c(d) db n ) Delta Delta Delta) ha(b 1 ; b n ) pi = a(c) d cd j d(b 1 ) cd j ....

G. Boudol. Some chemical abstract machines. In Proc. of REX School, Springer Lect. Notes in Comp. Sci. 803, 1993.

.... Preconditions containing relational operators are encoded as conditions, whereas the molecule corresponding to the variable is deleted and added again, as already described. This conforms to the chemical semantics where conditions can only be stated on local molecules involved in a rule [4]. It is possible to define many other functions to describe, for instance, when rules, namely operation schemas, can fire concurrently: it usually depends on their postconditions. 2.1 The logic We define now an execution model, that is a way of abstractly executing a Z specification document, and ....

G. Boudol. Some Chemical Abstract Machines. In J. deBakker, W. deRoever, and G. Rozenberg, editors, A Decade of Concurrency, volume 803 of Lecture Notes in Computer Science, pages 92--123. Springer-Verlag, Berlin, 1993.

....process notation. It is shown the process notation used can be translated into a graph reduction language. In Ostheimer and Davie [16] an encoding for shared reduction strategies was given in the (synchronous) monadic calculus but the correspondence to terms was not formalized. Boudol [4] encodes a version of calculus with explicit substitutions which provides sharing in an asynchronous version of calculus. The encoding is more complex and lacks the clear implementation route presented here. Wadsworth [20] introduced graph reduction for terms. In this paper we are interested ....

G. Boudol. Some chemical abstract machines. In A Decade of Concurrency --- Reflections and Perspectives, Proceedings of the REX School Symposium, volume 803 of LNCS, pages 92--123. Springer-Verlag, June 1993.

....neighbour communication. 3 Specifying Constraint Matching in Liam Liam is an abstract machine for Linda [Cam97] based upon the Chemical Abstract Machine (see below) The full description of Liam can be found in Appendix A. 3. 1 The Chemical Abstract Machine The Chemical Abstract Machine (CHAM) [BB92, Bou94] is based upon a chemical metaphor, as used in the GAMMA language [BCL88] The CHAM is claimed to be able to implement several known models of concurrent computation. It is also based on the idea of abstract machines inherited from the theory of sequential languages. GAMMA (General Abstract Model ....

G. Boudol. Some chemical abstract machines. In J. W. de Bakker, W.-P. de Roever, and G. Rozenberg, editors, A Decade of Concurrency, volume 803 of Lecture Notes in Computer Science, pages 92--123. Springer-Verlag, 1994.

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Gerard Boudol. Some chemical abstract machines. In A Decade of Concurrency, volume 803 of LNCS, pages 92--123. Springer-Verlag, 1994.

No context found.

Boudol, G.: Some Chemical Abstract Machines. In A Decade of Concurrency, number 803 in Lecture Notes in Computer Science, pp. 92-123. Springer-Verlag, May 1994.

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G. Boudol. Some Chemical Abstract Machines. In Proc. Rex School/Symposium 1993.

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Gerard Boudol. Some chemical abstract machines. In Jacobus W. de Bakker, Willem-Paul de Roever, and Grzegorz Rozenberg, editors, A Decade of Concurrency 1993 (REX Workshop), volume 803 of Lecture Notes in Computer Science, pages 92-123. Springer, 1994.

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G. Boudol. Some chemical abstract machines. In J.W. de Bakker, W.P. de Roever, and G. Rozenberg, editors, A Decade of Concurrency: Reflections and Perspectives, LNCS 803, pages 92--123. Springer-Verlag, 1993.

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