A Protocol for the Atomic Capture of Multiple Molecules at Large Scale

With the rise of service-oriented computing, applications are more and more based on coordination of autonomous services. Envisioned over largely distributed and highly dynamic platforms, expressing this coordination calls for alternative programming models. The chemical programming paradigm, which models applications as chemical solutions where molecules representing digital entities involved in the computation, react together to produce a result, has been recently shown to provide the needed abstractions for autonomic coordination of services. However, the execution of such programs over large scale platforms raises several problems hindering this paradigm to be actually leveraged. Among them, the atomic capture of molecules participating in concur- rent reactions is one of the most significant. In this paper, we propose a protocol for the atomic capture of these molecules distributed and evolving over a large scale platform. As the density of possible reactions is crucial for the liveness and efficiency of such a capture, the protocol proposed is made up of two sub-protocols, each of them aimed at addressing different levels of densities of potential reactions in the solution. While the decision to choose one or the other is local to each node participating in a program's execution, a global coherent behaviour is obtained. Proof of liveness, as well as intensive simulation results showing the efficiency and limited overhead of the protocol are given.Comment: 13th International Conference on Distributed Computing and Networking (2012

GLC actors, artificial chemical connectomes, topological issues and knots

Based on graphic lambda calculus, we propose a program for a new model of asynchronous distributed computing, inspired from Hewitt Actor Model, as well as several investigation paths, concerning how one may graft lambda calculus and knot diagrammatics

Minimization Strategies for Maximally Parallel Multiset Rewriting Systems

Maximally parallel multiset rewriting systems (MPMRS) give a convenient way to express relations between unstructured objects. The functioning of various computational devices may be expressed in terms of MPMRS (e.g., register machines and many variants of P systems). In particular, this means that MPMRS are computationally complete; however, a direct translation leads to quite a big number of rules. Like for other classes of computationally complete devices, there is a challenge to find a universal system having the smallest number of rules. In this article we present different rule minimization strategies for MPMRS based on encodings and structural transformations. We apply these strategies to the translation of a small universal register machine (Korec, 1996) and we show that there exists a universal MPMRS with 23 rules. Since MPMRS are identical to a restricted variant of P systems with antiport rules, the results we obtained improve previously known results on the number of rules for those systems.Comment: This article is an improved version of [1

Blackboard Rules for Coordinating Context-aware Applications in Mobile Ad Hoc Networks

Thanks to improvements in wireless communication technologies and increasing computing power in hand-held devices, mobile ad hoc networks are becoming an ever-more present reality. Coordination languages are expected to become important means in supporting this type of interaction. To this extent we argue the interest of the Bach coordination language as a middleware that can handle and react to context changes as well as cope with unpredictable physical interruptions that occur in opportunistic network connections. More concretely, our proposal is based on blackboard rules that model declaratively the actions to be taken once the blackboard content reaches a predefined state, but also that manage the engagement and disengagement of hosts and transient sharing of blackboards. The idea of reactiveness has already been introduced in previous work, but as will be appreciated by the reader, this article presents a new perspective, more focused on a declarative setting.Comment: In Proceedings FOCLASA 2012, arXiv:1208.432

Distributed CCS

In this paper we describe a technique to extend a process language such as CCS which does not model many aspects of distributed computation to one which does. The idea is to use a concept of location which represents a virtual node. Processes at different locations can evolve independently. Furthermore, communication between the processes at different locations occurs via explicit message passing. We extend CCS with locations and message passing primitives and present its operational semantics. We show that the equivalences induced by the new semantics and its properties are similar to the equivalences in CCS. We also show how the semantics of configuration and routing can be handled

Spatial Computing as Intensional Data Parallelism

International audienceIn this paper, we show that various concepts and tools developed in the 90's in the field of data-parallelism provide a relevant spatial programming framework. It allows high level spatial computation specifications to be translated into efficient low-level operations on processing units. We provide some short examples to illustrate this statement

Adaptive atomic capture of multiple molecules

International audienceFacing the scale, heterogeneity and dynamics of the global computing platform emerging on top of the Internet, autonomic computing has been raised recently as one of the top challenges of computer science research. Such a paradigm calls for alternative programming abstractions, able to express autonomic behaviours. In this quest, nature-inspired analogies regained a lot of interest. More specifically, the chemical programming paradigm, which envisions a program's execution as a succession of reactions between molecules representing data to produce a result, has been shown to provide some adequate abstractions for the high-level specification of autonomic systems.However, conceiving a runtime able to run such a model over large-scale platforms raises several problems, hindering this paradigm to be actually leveraged. Among them, the atomic capture of multiple molecules participating in concurrent reactions is one of the most significant.In this paper, we propose a protocol for the atomic capture of these molecules distributed and evolving over a large-scale platform. As the density of potential reactions has a significant impact on the liveness and efficiency of such a capture, the protocol proposed is made up of two sub-protocols, each of them aimed at addressing different levels of densities of potential reactions in the solution. While the decision to choose one or the other is local to each node participating in a program's execution, a global coherent behaviour is obtained. We also give an overview of the course of execution when a program contains multiple rules and provide a rule-changing mechanism. The proof of correctness, as well as intensive simulation results showing the efficiency and limited overhead of the protocol are given

Distributed data structure for factored operating systems

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 151-158).Future computer architectures will likely exhibit increased parallelism through the addition of more processor cores. Architectural trends such as exponentially increasing parallelism and the possible lack of scalable shared memory motivate the reevaluation of operating system design. This thesis work takes place in the context of Factored Operating Systems which leverage distributed system ideas to increase the scalability of multicore processor operating systems. fos, a Factored Operating System, explores a new design point for operating systems where traditional low-level operating system services are fine-grain parallelized while internally only using explicit message passing for communication. fos factors an operating system first by system service and then further parallelizes inside of the system service by splitting the service into a fleet of server processes which communicate via messaging. Constructing parallel low-level operating system services which only internally use messaging is challenging because shared resources must be partitioned across servers and the services must provide scalable performance when met with uneven demand. To ease the construction of parallel fos system services, this thesis develops the dPool distributed data structure. The dPool data structure provides concurrent access to an unordered collection of elements by server processes within a fos fleet. Internal to a single dPool instance, all communication between different portions of a dPool is done via messaging. This thesis uses the dPool data structure within the parallel fos Physical Memory Allocation fleet and demonstrates that it is possible to use a dPool to manage shared state in a factored operating system's physical page allocator. This thesis begins by presenting the design of the prototype fos operating system. In the context of fos system service fleets, this thesis describes the dPool data structure, its design, different implementations, and interfaces. The dPool data structure is shown to achieve scalability across even and uneven micro-benchmark workloads. This thesis shows that common parallel and distributed programming techniques apply to the creation of dPool and that background threads within a dPool can increase performance. Finally, this thesis evaluates different dPool implementations and demonstrates that intelligently pushing elements between dPool parts can increase scalability.by David Wentzlaff.Ph.D