During the last years, several enterprise modeling languages became de-facto standards in their particular field of application. This dissemination increased the need for extending these languages in order to both spe...
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ISBN:
(纸本)9781467392037
During the last years, several enterprise modeling languages became de-facto standards in their particular field of application. This dissemination increased the need for extending these languages in order to both specify concepts domain-specifically and integrate additional concepts. However, only the minority of enterprise modeling languages provides an extension mechanism and even those defining one, reveal some syntactical shortcomings. This issue can be also observed in the context of the well-known meta modeling language MOF and its correspondingly defined enterprise modeling languages like BPMN. This position paper therefore elaborates an adaptation of the profile mechanism from UML for generic extensions of meta models in the field of enterprise modeling. Therefore, the characteristics of profiling are abstracted to the meta meta model layer and comprehensively integrated within an framework for the integrated definition of meta models. The Stereotype concept is thereby applied to several parts of meta models including also aspects of the concrete syntax as well as semantics. The proposed framework serves as reference architecture for the derivation of meta modeling language specific implementations (e.g., within MOF).
Business Process Model and Notation (BPMN), now at version 2.0.2, provides a standard graphical representation for specifying business processes. In this paper we report on the first stage of a semantic investigation ...
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ISBN:
(纸本)9781467382007
Business Process Model and Notation (BPMN), now at version 2.0.2, provides a standard graphical representation for specifying business processes. In this paper we report on the first stage of a semantic investigation of BPMN, using methods in the tradition of programminglanguages semantics. We consider a control-flow subset of BPMN and an execution architecture based on an intermediate language that we name L-BPMN. The execution architecture comprises two main components: a translator which takes as input a BPMN model and generates L-BPMN code, and an interpreter for L-BPMN. L-BPMN is a process oriented imperative language providing a combination of concepts, including maximal parallelism and durational activities. We employ the mathematical methodology of metric semantics in designing and relating an operational semantics O and a denotational semantics D for L-BPMN. We establish the formal relation between O and D by using an abstraction operator and a fixed point argument. In this way we prove the correctness of the denotational semantics with respect to the operational semantics. We focus on the semantic investigation of BPMN. We also explain how the operational semantics can serve as a blueprint for an implementation on a client-server architecture.
We present a "negative" semantics of the C11 language-a semantics that does not just give meaning to correct programs, but also rejects undefined programs. We investigate undefined behavior in C and discuss ...
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ISBN:
(纸本)9781450334686
We present a "negative" semantics of the C11 language-a semantics that does not just give meaning to correct programs, but also rejects undefined programs. We investigate undefined behavior in C and discuss the techniques and special considerations needed for formally specifying it. We have used these techniques to modify and extend a semantics of C into one that captures undefined behavior. The amount of semantic infrastructure and effort required to achieve this was unexpectedly high, in the end nearly doubling the size of the original semantics. From our semantics, we have automatically extracted an undefinedness checker, which we evaluate against other popular analysis tools, using our own test suite in addition to a third-party test suite. Our checker is capable of detecting examples of all 77 categories of core language undefinedness appearing in the C11 standard, more than any other tool we considered. Based on this evaluation, we argue that our work is the most comprehensive and complete semantic treatment of undefined behavior in C, and thus of the C language itself.
This paper is a contribution to the study of a special kind of syllogisms with intermediate quantifiers. We stem from our previous papers where a formal theory of the intermediate quantifiers was introduced. Besides o...
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ISBN:
(纸本)9781467374286
This paper is a contribution to the study of a special kind of syllogisms with intermediate quantifiers. We stem from our previous papers where a formal theory of the intermediate quantifiers was introduced. Besides other results, we syntactically proved validity of 105 basic syllogisms with them. We also demonstrated how our theory works in the semantic interpretation. In this paper, we will address some special kinds of syllogisms that are non-trivial in the sense that both premises as well as conclusion contain general intermediate quantifiers.
Two programs P and Q are partially equivalent if, when both terminate on the same input, they end up with equivalent outputs. Establishing partial equivalence is useful in, e.g., compiler verification, when P is the s...
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ISBN:
(纸本)9781479984480
Two programs P and Q are partially equivalent if, when both terminate on the same input, they end up with equivalent outputs. Establishing partial equivalence is useful in, e.g., compiler verification, when P is the source program and Q is the target program, or in compiler optimisation, when P is the initial program and Q is the optimised program. A program R is partially correct if, when it terminates, it ends up in a "good" state. We show that, somewhat surprisingly, the problem of establishing partial equivalence can be reduced to the problem of showing partial correctness in an aggregated language, where programs R consist of pairs of programs < P, Q >. Our method is crucially based on the recently-introduced matching logic, which allows to faithfully define the operational semantics of any language. We show that we can construct the aggregated language mechanically, from the semantics of the initial languages. Furthermore, matching logic gives us for free a proof system for partial correctness for the resulting language. This proof system can then be used to prove partial equivalence.
AADL (Architectural Analysis and Design language) can describe the architecture of an embedded control system at various levels of abstraction. In addition, AADL supports refinement mechanisms for refining abstract mo...
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ISBN:
(纸本)9781479966295
AADL (Architectural Analysis and Design language) can describe the architecture of an embedded control system at various levels of abstraction. In addition, AADL supports refinement mechanisms for refining abstract models to more detailed ones. However, the refinement mechanism in AADL is of informal nature. Event-B is an independent formal modelling notation for rigorous development of software systems. In Event-B, consistency of a model and refinement relationship can be formally verified. In this paper, we consider a meaningful subset of AADL, and give its semantics in terms of refinement and model decomposition mechanism of Event-B. An AADL model at any level of abstraction can be mapped to an Event-B model, and in the process, the informal refinement relationship between AADL models can be formalized in Event-B. In addition, the decomposition of a component into sub-components can be mapped to Event-B decomposition. We discuss our approach by referring to the case study of a simplified Cruise Controller.
Structural operational semantics provides a well-known framework to describe the semantics of programminglanguages, lending itself to formalization in theorem provers. The formalization of syntactic SOS rule formats,...
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ISBN:
(纸本)9780769550534
Structural operational semantics provides a well-known framework to describe the semantics of programminglanguages, lending itself to formalization in theorem provers. The formalization of syntactic SOS rule formats, which enforce some form of well-behavedness, has so far received less attention. GSOS is a rule format that enjoys the property that the operational semantics and denotational semantics, both derived from the same set of GSOS rules, are consistent. The present paper formalizes the underlying theory in the theorem prover COQ, and proves the consistency property, also known as the adequacy theorem. The inspiration for our work has been drawn from the field of bialgebraic semantics.
Various cryptographic constructions allow an un-trusted cloud server to compute over encrypted data, without decrypting the data. However, this prevents the cloud server from branching according to encrypted values. W...
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ISBN:
(纸本)9780769550312
Various cryptographic constructions allow an un-trusted cloud server to compute over encrypted data, without decrypting the data. However, this prevents the cloud server from branching according to encrypted values. We study the constraints imposed by this important scenario by formulating and solving an equivalent information-flow problem, based on assuming an adversary could observe the control path. We develop a type system that prevents control-path information leaks, prove soundness, and compare with traditional implicit information-flow. Because simply preventing programs that leak information severely restricts the language, we define alternate (and easily implemented) semantics that execute multiple paths and combine the results using data operations. This produces a termination problem which we address with a more refined type system that characterizes a useful class of obliviously executable programs. We prove fundamental results about this language, semantics, and type system and conclude by comparing with traditional timing-based information-flow.
A major open question for advocates of Model-Based Systems Engineering (MBSE) is the question of how system and subsystem engineers will work together. The Systems Modeling language (SysML), like any language intended...
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ISBN:
(纸本)9781467318112
A major open question for advocates of Model-Based Systems Engineering (MBSE) is the question of how system and subsystem engineers will work together. The Systems Modeling language (SysML), like any language intended for a large audience, is in tension between the desires for simplicity and for expressiveness. In order to be more expressive, many specialized language elements may be introduced, which will unfortunately make a complete understanding of the language a more daunting task. While this may be acceptable for systems modelers, it will increase the challenge of including subsystem engineers in the modeling effort. One possible answer to this situation is the use of Domain-Specific languages (DSL), which are fully supported by the Unified Modeling language (UML). SysML is in fact a DSL for systems engineering. The expressive power of a DSL can be enhanced through the use of diagram customization. Various domains have already developed their own schematic vocabularies. Within the space engineering community, two excellent examples are the propulsion and telecommunication subsystems. A return to simple box-and-line diagrams (e. g., the SysML Internal Block Diagram) are in many ways a step backward. In order allow subsystem engineers to contribute directly to the model, it is necessary to make a system modeling tool at least approximate in accessibility to drawing tools like Microsoft PowerPoint and Visio. The challenge is made more extreme in a concurrent engineering environment, where designs must often be drafted in an hour or two. In the case of the Jet Propulsion Laboratory's Team X concurrent design team, a subsystem is specified using a combination of PowerPoint for drawing and Excel for calculation. A pilot has been undertaken in order to meld the drawing portion and the production of master equipment lists (MELs) via a SysML authoring tool, MagicDraw. Team X currently interacts with its customers in a process of sharing presentations. There are several
When running big parallel computations on thousands of processors, the probability that an individual processor will fail during the execution cannot be ignored. Computations should be replicated, or else failures sho...
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ISBN:
(纸本)9780769550534
When running big parallel computations on thousands of processors, the probability that an individual processor will fail during the execution cannot be ignored. Computations should be replicated, or else failures should be detected at run-time and failed subcomputations reexecuted. We follow the latter approach and propose a high-level operational semantics that detects computation failures, and allows failed computations to be restarted from the point of failure. We implement this high-level semantics with a lower-level operational semantics that provides a more accurate account of processor failures, and prove in Coq the correspondence between the high- and low-level semantics.
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