1,721,087 research outputs found
A Query Language Based on the Ambient Logic
No full textThe ambient logic is a modal logic proposed to describe the structural and computational properties of distributed and mobile computation. The structural part of the ambient logic is, essentially, a logic of labeled trees, hence it turns out to be a good foundation for query languages for semistructured data, much in the same way as first order logic is a fitting foundation for relational query languages. We define here a query language for semistructured data that is based on the ambient logic, and we outline an execution model for this language. The language turns out to be quite expressive. Its strong foundations and the equivalences that hold in the ambient logic are helpful in the definition of the language semantics and execution model
Ambient Groups and Mobility Types
No full textWe add name groups and group creation to the typed ambient calculus. Group creation is surprisingly interesting: it has the effect of statically preventing certain communications, and can thus block the accidental or malicious escape of capabilities that is a major concern in practical systems. Moreover, ambient groups allow us to refine our earlier work on type systems for ambient mobility. We present type systems in which groups identify the set of ambients that a process may cross or open
Manipulating Trees with Hidden Labels
No full textWe define an operational semantics and a type system for manipulating semistructured data that contains hidden information. The data model is simple labeled trees with a hiding operator. Data manipulation is based on pattern matching, with types that track the use of hidden labels. © 2007 Elsevier B.V. All rights reserved
Types for the Ambient Calculus
No full textThe ambient calculus is a concurrent calculus where the unifying notion of ambient is used to model many different constructs for distributed and mobile computation. We study a type system that describes several properties of ambient behavior. The type system allows ambients to be partitioned in disjoint sets (groups), according to the intended design of a system, in order to specify both the communication and the mobility behavior of ambients
Secrecy and Group Creation
No full textWe add an operation of group creation to the typed pi-calculus, where a group is a type for channels. Creation of fresh groups has the effect of statically preventing certain communications, and can block the accidental or malicious leakage of secrets. We adapt a notion of secrecy introduced by Abadi, and prove a preservation of secrecy property. When applied to the ambient calculus, the same notion of group creation can be used to create and preserve shared secrets among mobile agents. © Elsevier Ltd
Galileo: A Strongly Typed, Interactive Conceptual Language
Full text linkGalileo, a programming language for database applications, is presented. Galileo is a strongly-typed, interactive programming language designed specifically to support semantic data model features (classification, aggregation, and specialization), as well as the abstraction mechanisms of modern programming languages (types, abstract types, and modularization). The main contributions of Galileo are (a) a flexible type system to model database structure and semantic integrity constraints; (b) the inclusion of type hierarchies to support the specialization abstraction mechanisms of semantic data models; (c) a modularization mechanism to structure data and operations into interrelated units (d) the integration of abstraction mechanisms into an expression-based language that allows interactive use of the database without resorting to a new stand-alone query language. Galileo will be used in the immediate future as a tool for database design and, in the long term, as a high-level interface for DBMSs
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