Compositionality of aspect weaving.

One approach towards adaptivity is aspect-orientation. As- pects enable the systematic addition of code into existing programs. In order to provide safe and at the same time flexible aspects for such adap- tive systems we address the verification of the aspect-oriented language paradigm. This paper first gives an overview of our aspect calculus and summarizes previous results. Then we present a new compositionality lemma prerequisite for so-called run-time weaving. The entire theory and proofs are carried out in the theorem prover Isabelle/HOL

Composing safely: a type system for aspects

In this paper we present an approach towards safe software composition based on aspect-orientation. Aspects enable the systematic addition of code into existing programs but often they also introduce er- rors. In order to provide safe aspects for software composition we address the verification of the aspect-oriented language paradigm. We construct a basic calculus for aspects with types and prove formally type safety. More precisely, this paper presents the following contributions (a) a fully formalized type system for the Theory of Objects including the proof of type safety, (b) a theory of aspects based on the Theory of Objects including a type system for aspects, and (c) the definition of a notion of type safety for aspects including its proof. The entire theory and proofs are carried out in the theorem prover Isabelle/HOL

A Formalization of Typed Aspects for the ς-calculus in Isabelle/HOL

In this paper we present an approach towards safe software composition based on aspect-orientation. Aspects enable the systematic addition of code into existing programs but often they also introduce errors. In order to provide safe aspects for software composition we address the verification of the aspect-oriented language paradigm. We construct a basic calculus for aspects with types and prove formally type safety. More precisely, this paper presents the following contributions (a) a fully formalized type system for the Theory of Objects including the proof of type safety, (b) a theory of aspects based on the Theory of Objects including a type system for aspects, and (c) the definition of a notion of type safety for aspects including its proof. The entire theory and proofs are carried out in the theorem prover Isabelle/HOL

A locally nameless theory of objects

This paper presents the formalisation of an object calculus in Isabelle/HOL highlighting the binder technique called locally nameless1. This techniques has its origins already in a note at the end of de Bruijn’s paper [5] introducing the classical de Bruijn indices. In the last few years, with the advent of mechanized proofs in the domain of programming languages, e.g. [1], this technique attracted new attention. The most recent work on locally nameless technique [2] provides cofinite quantification, necessary for proving non-trivial properties. Indeed the de Bruijn indices are often criticised, as being too technical, that is why alternative techniques are investigated. The de Bruijn indices method, however, is known to be reliable, and is often chosen in order to focus on aspects of programming languages unrelated to variable bindings. With locally nameless techniques, one expects to spend less time proving auxiliary lemmas dealing with variable bind- ings, but also to obtain theorems that are more convincing because closer to the paper version. Our contributions are a formalisation in Isabelle/HOL of ς-calculus; and an in depth comparison of both locally nameless and de Bruijn complete mechanisations including specification and proofs

Monitoring synaptic transmission in primary neuronal cultures using local extracellular stimulation

Various techniques have been applied for the functional analysis of synaptic transmission in Cultured neurons. Here, we describe a method of studying synaptic transmission in neurons cultured at high-density from different brain regions such as the cortex, striatum and spinal cord. We use postsynaptic whole-cell recordings to monitor synaptic Currents triggered by presynaptic action potentials that are induced by brief stimulations with a nearby extracellular bipolar electrode. Pharmacologically isolated excitatory or inhibitory postsynaptic currents can be reliably induced, with amplitudes, synaptic charge transfers, and short-term plasticity properties that are reproducible from culture to culture. We show that the size and kinetics of pharmacologically isolated inhibitory postsynaptic Currents triggered by single action potentials or stimulus trains depend on the Ca2+ concentration, temperature and stimulation frequency. This method can be applied to study synaptic transmission in wildtype neurons infected with lentiviruses encoding various components of presynaptic release machinery, or in neurons from genetically modified mice, for example neurons carrying floxed genes in which gene expression can be acutely ablated by expression of Cre recombinase. The preparation described in this paper should be useful for analysis of synaptic transmission in inter-neuronal synapses formed by different types of neurons. (c) 2006 Elsevier B.V. All rights reserved

Structure of the first C\u3csub\u3e2\u3c/sub\u3e domain of synaptotagmin I: A Novel CA(2+)/Phospholipid-Binding Fold

C2 domains are regulatory sequence motifs that occur widely in nature. Synaptotagmin I, a synaptic vesicle protein involved in the Ca2+ regulation of exocytosis, contains two C2 domains, the first of which acts as a Ca2+ sensor. We now describe the three-dimensional structure of this C2 domain at 1.9 Å resolution in both the Ca2+-bound and Ca2+-free forms. The C2 polypeptide forms an eight-stranded β sandwich constructed around a conserved four-stranded motif designated as a C2 key. Ca2+ binds in a cup-shaped depression between two polypeptide loops located at the N- and C-termini of the C2-key motif

ASPfun: A Functional and Distributed Object Calculus Semantics, Type-system, and Formalization

Several paradigms exist for distributed computing, this paper tries to provide a sound foundation for autonomous objects communicating in a very structured way. We define ASPfun, a calculus of functional objects, behaving autonomously, and communicating by a request-reply mechanism: requests are method calls handled asynchronously, futures represent awaited results for requests, and replies return the result of a request to an object that holds the corresponding future. This report first presents the ASPfun calculus and its semantics. Secondly we provide a type system for ASPfun, which ensure the ``progress'' property: while there is a request that is not reduced to a value, the computation can continue. ASPfun and its properties have been formalized and proved using the Isabelle theorem prover

ASPfun: A Functional and Distributed Object Calculus Semantics, Type-system, and Formalization

Several paradigms exist for distributed computing, this paper tries to provide a sound foundation for autonomous objects communicating in a very structured way. We define ASPfun, a calculus of functional objects, behaving autonomously, and communicating by a request-reply mechanism: requests are method calls handled asynchronously, futures represent awaited results for requests, and replies return the result of a request to an object that holds the corresponding future. This report first presents the ASPfun calculus and its semantics. Secondly we provide a type system for ASPfun, which ensure the ``progress'' property: while there is a request that is not reduced to a value, the computation can continue. ASPfun and its properties have been formalized and proved using the Isabelle theorem prover