19 research outputs found
Types for BioAmbients
The BioAmbients calculus is a process algebra suitable for representing
compartmentalization, molecular localization and movements between
compartments. In this paper we enrich this calculus with a static type system
classifying each ambient with group types specifying the kind of compartments
in which the ambient can stay. The type system ensures that, in a well-typed
process, ambients cannot be nested in a way that violates the type hierarchy.
Exploiting the information given by the group types, we also extend the
operational semantics of BioAmbients with rules signalling errors that may
derive from undesired ambients' moves (i.e. merging incompatible tissues).
Thus, the signal of errors can help the modeller to detect and locate unwanted
situations that may arise in a biological system, and give practical hints on
how to avoid the undesired behaviour
A Process Calculus for Molecular Interaction Maps
We present the MIM calculus, a modeling formalism with a strong biological
basis, which provides biologically-meaningful operators for representing the
interaction capabilities of molecular species. The operators of the calculus
are inspired by the reaction symbols used in Molecular Interaction Maps (MIMs),
a diagrammatic notation used by biologists. Models of the calculus can be
easily derived from MIM diagrams, for which an unambiguous and executable
interpretation is thus obtained. We give a formal definition of the syntax and
semantics of the MIM calculus, and we study properties of the formalism. A case
study is also presented to show the use of the calculus for modeling
biomolecular networks.Comment: 15 pages; 8 figures; To be published on EPTCS, proceedings of MeCBIC
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Stochastic Calculus of Wrapped Compartments
The Calculus of Wrapped Compartments (CWC) is a variant of the Calculus of
Looping Sequences (CLS). While keeping the same expressiveness, CWC strongly
simplifies the development of automatic tools for the analysis of biological
systems. The main simplification consists in the removal of the sequencing
operator, thus lightening the formal treatment of the patterns to be matched in
a term (whose complexity in CLS is strongly affected by the variables matching
in the sequences).
We define a stochastic semantics for this new calculus. As an application we
model the interaction between macrophages and apoptotic neutrophils and a
mechanism of gene regulation in E.Coli
A Type System for a Stochastic CLS
The Stochastic Calculus of Looping Sequences is suitable to describe the
evolution of microbiological systems, taking into account the speed of the
described activities. We propose a type system for this calculus that models
how the presence of positive and negative catalysers can modify these speeds.
We claim that types are the right abstraction in order to represent the
interaction between elements without specifying exactly the element positions.
Our claim is supported through an example modelling the lactose operon
A Calculus of Looping Sequences with Local Rules
In this paper we present a variant of the Calculus of Looping Sequences (CLS
for short) with global and local rewrite rules. While global rules, as in CLS,
are applied anywhere in a given term, local rules can only be applied in the
compartment on which they are defined. Local rules are dynamic: they can be
added, moved and erased. We enrich the new calculus with a parallel semantics
where a reduction step is lead by any number of global and local rules that
could be performed in parallel. A type system is developed to enforce the
property that a compartment must contain only local rules with specific
features. As a running example we model some interactions happening in a cell
starting from its nucleus and moving towards its mitochondria.Comment: In Proceedings DCM 2011, arXiv:1207.682
Process algebra modelling styles for biomolecular processes
We investigate how biomolecular processes are modelled in process algebras, focussing on chemical reactions. We consider various modelling styles and how design decisions made in the definition of the process algebra have an impact on how a modelling style can be applied. Our goal is to highlight the often implicit choices that modellers make in choosing a formalism, and illustrate, through the use of examples, how this can affect expressability as well as the type and complexity of the analysis that can be performed
Towards modular verification of pathways: fairness and assumptions
Modular verification is a technique used to face the state explosion problem
often encountered in the verification of properties of complex systems such as
concurrent interactive systems. The modular approach is based on the
observation that properties of interest often concern a rather small portion of
the system. As a consequence, reduced models can be constructed which
approximate the overall system behaviour thus allowing more efficient
verification.
Biochemical pathways can be seen as complex concurrent interactive systems.
Consequently, verification of their properties is often computationally very
expensive and could take advantage of the modular approach.
In this paper we report preliminary results on the development of a modular
verification framework for biochemical pathways. We view biochemical pathways
as concurrent systems of reactions competing for molecular resources. A modular
verification technique could be based on reduced models containing only
reactions involving molecular resources of interest.
For a proper description of the system behaviour we argue that it is
essential to consider a suitable notion of fairness, which is a
well-established notion in concurrency theory but novel in the field of pathway
modelling. We propose a modelling approach that includes fairness and we
identify the assumptions under which verification of properties can be done in
a modular way.
We prove the correctness of the approach and demonstrate it on the model of
the EGF receptor-induced MAP kinase cascade by Schoeberl et al.Comment: In Proceedings MeCBIC 2012, arXiv:1211.347
A Minimal OO Calculus for Modelling Biological Systems
In this paper we present a minimal object oriented core calculus for
modelling the biological notion of type that arises from biological ontologies
in formalisms based on term rewriting. This calculus implements encapsulation,
method invocation, subtyping and a simple formof overriding inheritance, and it
is applicable to models designed in the most popular term-rewriting formalisms.
The classes implemented in a formalism can be used in several models, like
programming libraries.Comment: In Proceedings CompMod 2011, arXiv:1109.104
On Designing Multicore-Aware Simulators for Systems Biology Endowed with OnLine Statistics
The paper arguments are on enabling methodologies for the design of a fully parallel, online, interactive tool aiming to support the bioinformatics scientists .In particular, the features of these methodologies, supported by the FastFlow parallel programming framework, are shown on a simulation tool to perform the modeling, the tuning, and the sensitivity analysis of stochastic biological models. A stochastic simulation needs thousands of independent simulation trajectories turning into big data that should be analysed by statistic and data mining tools. In the considered approach the two stages are pipelined in such a way that the simulation stage streams out the partial results of all simulation trajectories to the analysis stage that immediately produces a partial result. The simulation-analysis workflow is validated for performance and effectiveness of the online analysis in capturing biological systems behavior on a multicore platform and representative proof-of-concept biological systems. The exploited methodologies include pattern-based parallel programming and data streaming that provide key features to the software designers such as performance portability and efficient in-memory (big) data management and movement. Two paradigmatic classes of biological systems exhibiting multistable and oscillatory behavior are used as a testbed