6204500
Underapproximating Predicate Transformers
We study the underapproximation of the predicate transformers used to give semantics to the modalities in dynamic and temporal logic. Because predicate transformers operate on state sets, we define appropriate powerdomains for sound approximation. We study four such domains — two are based on “set inclusion” approximation, and two are based on “quantification” approximation — and we apply the domains to synthesize the most precise, underapproximating $\widetilde{pre}$ and pre transformers, in the latter case, introducing a focus operation. We also show why the expected abstractions of post and $\widetilde{post}$ are unsound, and we use the powerdomains to guide us to correct, sound underapproximations.
105294
Structure-Preserving Binary Relations for Program Abstraction
An abstraction is a property-preserving contraction of a program's model into a smaller one that is suitable for automated analysis. An abstraction must be sound, and ideally, complete. Soundness and completeness arguments are intimately connected to the abstraction process, and approaches based on homomorphisms and Galois connections are commonly employed to define abstractions and prove their soundness and completeness.This paper develops Mycroft and Jones's proposal that an abstraction should be stated as a form of structure-preserving binary relation. Mycroft-Jones-style relations are defined, developed, and employed in characterizations of the homomorphism and Galois-connection approaches to abstraction.
37519260
Trace-Based Abstract Interpretation of Operational Semantics
We present trace-based abstract interpretation, a unification of severallines of research on applying Cousot-Cousot-style abstract interpretation a.i. tooperational semantics definitions (such as flowchart, big-step, and small-step semantics)that express a program‘s semantics as a concrete computation tree of trace paths. Aprogram‘s trace-based a.i. is also a computation tree whose nodes contain abstractions ofstate and whose paths simulate the paths in the program‘s concrete computation tree.Using such computation trees, we provide a simple explanation of the central concept of collecting semantics, and we distinguish concrete from abstract collectingsemantics and state-based from path-based collecting semantics. We also expose therelationship between collecting semantics extraction and results garnered from flow-analytic and model-checking-based analysis techniques. We adapt concepts fromconcurrency theory to formalize “safe” and “live” a.i.‘s for computation trees; in particular, coinduction techniques help extend fundamental results to infinite computation trees.Problems specific to the various operational semantics methodologies are discussed: Big-step semantics cannot express divergence, so we employ a mixture of induction andcoinduction in response; small-step semantics generate sequences of programconfigurations unbounded in size, so we abstractly interpret source language syntax.Applications of trace-based a.i. to data-flow analysis, model checking, closure analysis,and concurrency theory are demonstrated.
16028114
Modal Transition Systems: A Foundation for Three-Valued Program Analysis
We present Kripke modal transition systems (Kripke MTSs), a generalization of modal transition systems [27, 26], as a foundation for three-valued program analysis. The semantics of Kripke MTSs are presented by means of a mixed power domain of states; soundness and consistency are proved. Two major applications, model checking partial state spaces and three-valued program shape analysis, are presented as evidence of the suitability of Kripke MTSs as a foundation for three-valued analyses.
207550710
Induction, Domains, Calculi: Strachey's Contributions to Programming-Language Engineering
In collaboration with his colleagues at Oxford, Christopher Strachey pioneered the analysis of programming languages in terms of semantic features. Three of Strachey's contributions—inductive definition of semantics, semantic-domain definitions, and calculi for semantic description—are presented, and their consequences on languages research are described. Strachey's impact, present and future, on the computer programming “mainstream” is also outlined.
7872163
Closed and Logical Relations for Over- and Under-Approximation of Powersets
We redevelop and extend Dams’s results on over- and under-approximation with higher-order Galois connections:
8977671
A flexible image search engine
ndessaig 63 ireste.fr Multimedia searching over Internet has gained substantial popularity in the past two years. Java’s networking features, along with the growing number of Web browsers that can execute Java apple&, facilitate distributed processing. Networking and computational performances are key concerns when considering the use of Java to develop performancesensitive distributed multimedia search engines. This paper describes MISE, the MediaSys Image Search Engine over a large-scale network. After an overview of the architecture, we present the search capabilities of MISE as companion part of image processing.
7135801
Experience Using Design Patterns to Evolve Communication Software Across Diverse OS Platforms
Design patterns help to improve communication software quality since they address a fundamental challenge in large-scale software development: communication of architectural knowledge among developers. This paper makes several contributions to the study and practice of design patterns. It presents a case study that illustrates how design patterns helped to reduce development effort and project risk when evolving an object-oriented telecommunication software framework across UNIX and Windows NT OS platforms. Second, the paper discusses the techniques, benefits, and limitations of applying a design pattern-based reuse strategy to commercial telecommunication software systems.
16978964
Domain-specific modeling languages for configuring and evaluating enterprise DRE system quality of service
The quality of service (QoS) of enterprise distributed real-time and embedded (DRE) systems can degrade under certain operating conditions and system architectures. This paper provides two contributions to research on model-driven development (MDD) tools and methods that help identify and rectify these QoS problems in component-based enterprise DRE systems. First, we show how MDD tools can be used to simplify and automate the evaluation of component-based DRE systems to identify QoS problems. Second, we show how MDD tools can be used to specify alternative QoS polices for component-based DRE systems and synthesize metadata automatically to simplify system (re)configurations that rectify QoS problems. We illustrate our MDD tools on a case study of multi-layer resource management services for shipboard computing systems that automate many aspects of power, navigation, command and control, and tactical operations
11437113
The Design and Performance of a Scalable ORB Architecture for CORBA Asynchronous Messaging
Historically, method-oriented middleware, such as Sun RPC, DCE, Java RMI, COM, and CORBA, has provided synchronous method invocation (SMI) models to applications. Although SMI works well for conventional client/server applications, it is not well-suited for highperformance or real-time applications due to its lack of scalability. To address this problem, the OMG has recently standardized an asynchronous method invocation (AMI) model for CORBA. AMI provides CORBA with many of the capabilities associated traditionally with messageoriented middleware, without incurring the key drawbacks of messageoriented middleware.
40642183
A Platform-Independent Component Modeling Language for Distributed Real-Time and Embedded Systems
This paper provides two contributions to the study of developing and applying domain-specific modeling languages (DSMLS) to distributed real-time and embedded (DRE) systems - particularly those systems using standards-based QoS-enabled component middleware. First, it describes the platform-independent component modeling language (PICML), which is a DSML that enables developers to define component interfaces, QoS parameters and software building rules, and also generates descriptor files that facilitate system deployment. Second, it applies PICML to an unmanned air vehicle (UAV) application portion of an emergency response system to show how PICML resolves key component-based DRE system development challenges. Our results show that the capabilities provided by PICML - combined with its design and deployment-time validation capabilities - eliminates many common errors associated with conventional techniques, thereby increasing the effectiveness of applying QoS-enabled component middleware technologies to the DRE system domain.