1,208 research outputs found
Semantics of a Typed Algebraic Lambda-Calculus
Algebraic lambda-calculi have been studied in various ways, but their
semantics remain mostly untouched. In this paper we propose a semantic analysis
of a general simply-typed lambda-calculus endowed with a structure of vector
space. We sketch the relation with two established vectorial lambda-calculi.
Then we study the problems arising from the addition of a fixed point
combinator and how to modify the equational theory to solve them. We sketch an
algebraic vectorial PCF and its possible denotational interpretations
Semantics-based Automated Web Testing
We present TAO, a software testing tool performing automated test and oracle
generation based on a semantic approach. TAO entangles grammar-based test
generation with automated semantics evaluation using a denotational semantics
framework. We show how TAO can be incorporated with the Selenium automation
tool for automated web testing, and how TAO can be further extended to support
automated delta debugging, where a failing web test script can be
systematically reduced based on grammar-directed strategies. A real-life
parking website is adopted throughout the paper to demonstrate the effectivity
of our semantics-based web testing approach.Comment: In Proceedings WWV 2015, arXiv:1508.0338
Inference Optimization using Relational Algebra
Exact inference procedures in Bayesian networks can be expressed using relational algebra; this provides a common ground for optimizations from the AI and database communities. Specifically, the ability to accomodate sparse representations of probability distributions opens up the way to optimize for their cardinality instead of the dimensionality; we apply this in a sensor data model.\u
Denotational, Causal, and Operational Determinism in Event Structures
Determinism is a theoretically and practically important concept in labelled transition systems and trees. We study its generalisation to event structures. It turns out that the result depends on what characterising property of tree determinism one sets out to generalise. We present three distinct notions of event structure determinism, and show that none of them shares all the pleasant properties of the one concept for trees
Timed Soft Concurrent Constraint Programs: An Interleaved and a Parallel Approach
We propose a timed and soft extension of Concurrent Constraint Programming.
The time extension is based on the hypothesis of bounded asynchrony: the
computation takes a bounded period of time and is measured by a discrete global
clock. Action prefixing is then considered as the syntactic marker which
distinguishes a time instant from the next one. Supported by soft constraints
instead of crisp ones, tell and ask agents are now equipped with a preference
(or consistency) threshold which is used to determine their success or
suspension. In the paper we provide a language to describe the agents behavior,
together with its operational and denotational semantics, for which we also
prove the compositionality and correctness properties. After presenting a
semantics using maximal parallelism of actions, we also describe a version for
their interleaving on a single processor (with maximal parallelism for time
elapsing). Coordinating agents that need to take decisions both on preference
values and time events may benefit from this language. To appear in Theory and
Practice of Logic Programming (TPLP)
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