A Provenance Tracking Model for Data Updates

For data-centric systems, provenance tracking is particularly important when the system is open and decentralised, such as the Web of Linked Data. In this paper, a concise but expressive calculus which models data updates is presented. The calculus is used to provide an operational semantics for a system where data and updates interact concurrently. The operational semantics of the calculus also tracks the provenance of data with respect to updates. This provides a new formal semantics extending provenance diagrams which takes into account the execution of processes in a concurrent setting. Moreover, a sound and complete model for the calculus based on ideals of series-parallel DAGs is provided. The notion of provenance introduced can be used as a subjective indicator of the quality of data in concurrent interacting systems.Comment: In Proceedings FOCLASA 2012, arXiv:1208.432

Abstract Interpretation for Probabilistic Termination of Biological Systems

In a previous paper the authors applied the Abstract Interpretation approach for approximating the probabilistic semantics of biological systems, modeled specifically using the Chemical Ground Form calculus. The methodology is based on the idea of representing a set of experiments, which differ only for the initial concentrations, by abstracting the multiplicity of reagents present in a solution, using intervals. In this paper, we refine the approach in order to address probabilistic termination properties. More in details, we introduce a refinement of the abstract LTS semantics and we abstract the probabilistic semantics using a variant of Interval Markov Chains. The abstract probabilistic model safely approximates a set of concrete experiments and reports conservative lower and upper bounds for probabilistic termination

Pumps Systems of Membranes

The reactivity of the living cells provides the real complexity of biological systems. This paper presents a reactive P system where the rules are triggered by certain conditions, and pumps are the parallel processors of a membrane. The computation of a reactive P system is given by parallel composition of conditional rules regarding the pumps, and by sequential and parallel composition of internal rules regarding the coordination activity of the membrane nucleus. Starting from this description, it is possible to de¯ne the operational semantics and various behavioural equivalences between mem- branes. Finally, some perspectives and open problems are presented. Overall this approach is a step toward a programming paradigm inspired by membrane activity

Local Type Checking for Linked Data Consumers

The Web of Linked Data is the cumulation of over a decade of work by the Web standards community in their effort to make data more Web-like. We provide an introduction to the Web of Linked Data from the perspective of a Web developer that would like to build an application using Linked Data. We identify a weakness in the development stack as being a lack of domain specific scripting languages for designing background processes that consume Linked Data. To address this weakness, we design a scripting language with a simple but appropriate type system. In our proposed architecture some data is consumed from sources outside of the control of the system and some data is held locally. Stronger type assumptions can be made about the local data than external data, hence our type system mixes static and dynamic typing. Throughout, we relate our work to the W3C recommendations that drive Linked Data, so our syntax is accessible to Web developers.Comment: In Proceedings WWV 2013, arXiv:1308.026

Scalable Grid-Based Implementation for Membrane Computing

We first present the formal semantics of a parallel rule-based formalism inspired by biological cells, and then provide a faithful parallel implementation of this computational model by using GridGain and taking care of various synchronization issues. Synchronization is achieved by using barriers and preconditions; both refer to the fact that a membrane can apply its rules only after it has received signals from the other related membranes. We develop a scalable parallel implementation using the MapReduce paradigm in GridGain which allows the splitting of a task into multiple subtasks, the parallel execution of these subtasks in parallel and the aggregation of the partial results into a single, final result. This implementation is very close to the formal description of this parallel model of membrane systems, a model which is computationally equivalent to Turing machines and able to provide polynomial solutions to NP-complete problems

What does P mean in Natural Computing?

Celebrating 70th birthday of Gheorghe Păun

A Bluetooth Solution for Public Information Systems

This paper gives insights into the opportunities offered by the Bluetooth technology. Bluetooth advertising proves to be a cheap and strong tool for enriching and improving the experience offered by a public transport system, by delivering dense and essential information about topics of interest. Alongside the Java platform, new applications can be designed and implemented to make use of the already available Bluetooth technology incorporated in devices in the target public’s custody. The paper sets focus on the segment of ready to be made available content regarding general information about the routes and timetables of the vehicles integrated in a public transport system.Public Transport, Bluetooth, Java, Mobile Device

Measurable Stochastics for Brane Calculus

We give a stochastic extension of the Brane Calculus, along the lines of recent work by Cardelli and Mardare. In this presentation, the semantics of a Brane process is a measure of the stochastic distribution of possible derivations. To this end, we first introduce a labelled transition system for Brane Calculus, proving its adequacy w.r.t. the usual reduction semantics. Then, brane systems are presented as Markov processes over the measurable space generated by terms up-to syntactic congruence, and where the measures are indexed by the actions of this new LTS. Finally, we provide a SOS presentation of this stochastic semantics, which is compositional and syntax-driven.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005

De Morgan Dual Nominal Quantifiers Modelling Private Names in Non-Commutative Logic

This paper explores the proof theory necessary for recommending an expressive but decidable first-order system, named MAV1, featuring a de Morgan dual pair of nominal quantifiers. These nominal quantifiers called `new' and `wen' are distinct from the self-dual Gabbay-Pitts and Miller-Tiu nominal quantifiers. The novelty of these nominal quantifiers is they are polarised in the sense that `new' distributes over positive operators while `wen' distributes over negative operators. This greater control of bookkeeping enables private names to be modelled in processes embedded as formulae in MAV1. The technical challenge is to establish a cut elimination result, from which essential properties including the transitivity of implication follow. Since the system is defined using the calculus of structures, a generalisation of the sequent calculus, novel techniques are employed. The proof relies on an intricately designed multiset-based measure of the size of a proof, which is used to guide a normalisation technique called splitting. The presence of equivariance, which swaps successive quantifiers, induces complex inter-dependencies between nominal quantifiers, additive conjunction and multiplicative operators in the proof of splitting. Every rule is justified by an example demonstrating why the rule is necessary for soundly embedding processes and ensuring that cut elimination holds.Comment: Submitted for review 18/2/2016; accepted CONCUR 2016; extended version submitted to journal 27/11/201