18,711 research outputs found
Model-Based Adaptation of Software Communicating via FIFO Buffers
Software Adaptation is a non-intrusive solution for composing black-box components or services (peers) whose individual functionality is as required for the new system, but that present interface mismatch, which leads to deadlock or other undesirable behaviour when combined. Adaptation techniques aim at automatically generating new components called adapters. All the interactions among peers pass through the adapter, which acts as an orchestrator and makes the involved peers work correctly together by compensating for mismatch. Most of the existing solutions in this field assume that peers interact synchronously using rendezvous communication. However, many application areas rely on asynchronous communication models where peers interact exchanging messages via buffers. Generating adapters in this context becomes a difficult problem because peers may exhibit cyclic behaviour, and their composition often results in infinite systems. In this paper, we present a method for automatically generating adapters in asynchronous environments where peers interact using FIFO buffers.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Orchestrated Session Compliance
We investigate the notion of orchestrated compliance for client/server
interactions in the context of session contracts. Devising the notion of
orchestrator in such a context makes it possible to have orchestrators with
unbounded buffering capabilities and at the same time to guarantee any message
from the client to be eventually delivered by the orchestrator to the server,
while preventing the server from sending messages which are kept indefinitely
inside the orchestrator. The compliance relation is shown to be decidable by
means of 1) a procedure synthesising the orchestrators, if any, making a client
compliant with a server, and 2) a procedure for deciding whether an
orchestrator behaves in a proper way as mentioned before.Comment: In Proceedings ICE 2015, arXiv:1508.0459
Demon Dynamics: Deterministic Chaos, the Szilard Map, and the Intelligence of Thermodynamic Systems
We introduce a deterministic chaotic system---the Szilard Map---that
encapsulates the measurement, control, and erasure protocol by which Maxwellian
Demons extract work from a heat reservoir. Implementing the Demon's control
function in a dynamical embodiment, our construction symmetrizes Demon and
thermodynamic system, allowing one to explore their functionality and recover
the fundamental trade-off between the thermodynamic costs of dissipation due to
measurement and due to erasure. The map's degree of chaos---captured by the
Kolmogorov-Sinai entropy---is the rate of energy extraction from the heat bath.
Moreover, an engine's statistical complexity quantifies the minimum necessary
system memory for it to function. In this way, dynamical instability in the
control protocol plays an essential and constructive role in intelligent
thermodynamic systems.Comment: 5 pages, 3 figures, supplementary materials;
http://csc.ucdavis.edu/~cmg/compmech/pubs/dds.ht
Magic-State Functional Units: Mapping and Scheduling Multi-Level Distillation Circuits for Fault-Tolerant Quantum Architectures
Quantum computers have recently made great strides and are on a long-term
path towards useful fault-tolerant computation. A dominant overhead in
fault-tolerant quantum computation is the production of high-fidelity encoded
qubits, called magic states, which enable reliable error-corrected computation.
We present the first detailed designs of hardware functional units that
implement space-time optimized magic-state factories for surface code
error-corrected machines. Interactions among distant qubits require surface
code braids (physical pathways on chip) which must be routed. Magic-state
factories are circuits comprised of a complex set of braids that is more
difficult to route than quantum circuits considered in previous work [1]. This
paper explores the impact of scheduling techniques, such as gate reordering and
qubit renaming, and we propose two novel mapping techniques: braid repulsion
and dipole moment braid rotation. We combine these techniques with graph
partitioning and community detection algorithms, and further introduce a
stitching algorithm for mapping subgraphs onto a physical machine. Our results
show a factor of 5.64 reduction in space-time volume compared to the best-known
previous designs for magic-state factories.Comment: 13 pages, 10 figure
Behavioral types in programming languages
A recent trend in programming language research is to use behav- ioral type theory to ensure various correctness properties of large- scale, communication-intensive systems. Behavioral types encompass concepts such as interfaces, communication protocols, contracts, and choreography. The successful application of behavioral types requires a solid understanding of several practical aspects, from their represen- tation in a concrete programming language, to their integration with other programming constructs such as methods and functions, to de- sign and monitoring methodologies that take behaviors into account. This survey provides an overview of the state of the art of these aspects, which we summarize as the pragmatics of behavioral types
A Model-based Approach for Designing Cyber-Physical Production Systems
The most recent development trend related to manufacturing is called "Industry 4.0". It proposes to transition from "blind" mechatronics systems to Cyber-Physical Production Systems (CPPSs). Such systems are capable of communicating with each other, acquiring and transmitting real-time production data. Their management and control require a structured software architecture, which is tipically referred to as the "Automation Pyramid". The design of both the software architecture and the components (i.e., the CPPSs) is a complex task, where the complexity is induced by the heterogeneity of the required functionalities. In such a context, the target of this thesis is to propose a model-based framework for the analysis and the design of production lines, compliant with the Industry 4.0 paradigm. In particular, this framework exploits the Systems Modeling Language (SysML) as a unified representation for the different viewpoints of a manufacturing system. At the components level, the structural and behavioral diagrams provided by SysML are used to produce a set of logical propositions about the system and components under design. Such an approach is specifically tailored towards constructing Assume-Guarantee contracts. By exploiting reactive synthesis techniques, contracts are used to prototype portions of components' behaviors and to verify whether implementations are consistent with the requirements. At the software level, the framework proposes a particular architecture based on the concept of "service". Such an architecture facilitates the reconfiguration of components and integrates an advanced scheduling technique, taking advantage of the production recipe SysML model. The proposed framework has been built coupled with the construction of the ICE Laboratory, a research facility consisting of a full-fledged production line. Such an approach has been adopted to construct models of the laboratory, to virtual prototype parts of the system and to manage the physical system through the proposed software architecture
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