490,168 research outputs found
A Coordination Language for Databases
We present a coordination language for the modeling of distributed database
applications. The language, baptized Klaim-DB, borrows the concepts of
localities and nets of the coordination language Klaim but re-incarnates the
tuple spaces of Klaim as databases. It provides high-level abstractions and
primitives for the access and manipulation of structured data, with integrity
and atomicity considerations. We present the formal semantics of Klaim-DB and
develop a type system that avoids potential runtime errors such as certain
evaluation errors and mismatches of data format in tables, which are monitored
in the semantics. The use of the language is illustrated in a scenario where
the sales from different branches of a chain of department stores are
aggregated from their local databases. Raising the abstraction level and
encapsulating integrity checks in the language primitives have benefited the
modeling task considerably
Towards Coordination-Intensive Visualization Software
Most coordination realizations in current visualization systems are ''last-minute'' ad-hoc and rely on the richness of the chosen implementation language. Moreover, very few visualization models implicitly consider coordination. If coordination is contemplated from the design point of view, it is usually only regarded as part of the communication protocol and is generally dealt with within that restricted domain. Coordinated multiple views are beneficial and a flexible model for coordination will ensure easy embedding of coordination in such exploratory environments. This paper compares different approaches to coordination in exploratory visualization (EV). We recognize the need for a coordination model and for that we formalize aspects of coordination in EV. Furthermore, our work draws on the findings of the interdisciplinary study of coordination by various researchers
S+Net: extending functional coordination with extra-functional semantics
This technical report introduces S+Net, a compositional coordination language
for streaming networks with extra-functional semantics. Compositionality
simplifies the specification of complex parallel and distributed applications;
extra-functional semantics allow the application designer to reason about and
control resource usage, performance and fault handling. The key feature of
S+Net is that functional and extra-functional semantics are defined
orthogonally from each other. S+Net can be seen as a simultaneous
simplification and extension of the existing coordination language S-Net, that
gives control of extra-functional behavior to the S-Net programmer. S+Net can
also be seen as a transitional research step between S-Net and AstraKahn,
another coordination language currently being designed at the University of
Hertfordshire. In contrast with AstraKahn which constitutes a re-design from
the ground up, S+Net preserves the basic operational semantics of S-Net and
thus provides an incremental introduction of extra-functional control in an
existing language.Comment: 34 pages, 11 figures, 3 table
Modeling adaptation with a tuple-based coordination language
In recent years, it has been argued that systems and applications, in order to deal with their increasing complexity, should be able to adapt their behavior according to new requirements or environment conditions. In this paper, we present a preliminary investigation aiming at studying how coordination languages and formal methods can contribute to a better understanding, implementation and usage of the mechanisms and techniques for adaptation currently proposed in the literature. Our study relies on the formal coordination language Klaim as a common framework for modeling some adaptation techniques, namely the MAPE-K loop, aspect- and context-oriented programming
Coordination and Learning with a Partial Language
This paper explores how efficiency promotes the use of structure in language. It starts from the premise that one of language’s central characteristics is to provide a means for saying novel things about novel circumstances, its creativity. It is reasonable to expect that in a rich and changing environment, language will be incomplete. This encourages reliance on structure. It is shown how creative language use emerges form common knowledge structures, even if those structures are consistent with an a priori absence of a common language. ZUSAMMENFASSUNG - (Koordination und Lernen mit einer Partialsprache) In diesem Beitrag wird die Anwendung von Strukturen in einer Sprache aus Effizienzsicht begründet. Der Artikel geht davon aus, daß eines der wichtigsten Merkmale der Sprache in ihrer Kreativität zu sehen ist, d. h. als Mittel, um Neues über neue Sachverhalte auszusagen. Es ist deshalb zu erwarten, daß in einer vielfältigen und sich verändernden Umwelt die Sprache unvollständig bleiben wird. Dies fördert die Anwendung von Strukturen. Es wird gezeigt, wie die kreative Sprachanwendung aus allgemeinen Wissensstrukturen entsteht, auch dann, wenn diese Strukturen a priori noch keine gemeinsame Sprache bilden.Language; Coordination; Optimal Learning; Common Knowledge
CREOLE: a Universal Language for Creating, Requesting, Updating and Deleting Resources
In the context of Service-Oriented Computing, applications can be developed
following the REST (Representation State Transfer) architectural style. This
style corresponds to a resource-oriented model, where resources are manipulated
via CRUD (Create, Request, Update, Delete) interfaces. The diversity of CRUD
languages due to the absence of a standard leads to composition problems
related to adaptation, integration and coordination of services. To overcome
these problems, we propose a pivot architecture built around a universal
language to manipulate resources, called CREOLE, a CRUD Language for Resource
Edition. In this architecture, scripts written in existing CRUD languages, like
SQL, are compiled into Creole and then executed over different CRUD interfaces.
After stating the requirements for a universal language for manipulating
resources, we formally describe the language and informally motivate its
definition with respect to the requirements. We then concretely show how the
architecture solves adaptation, integration and coordination problems in the
case of photo management in Flickr and Picasa, two well-known service-oriented
applications. Finally, we propose a roadmap for future work.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499
A Case Study in Coordination Programming: Performance Evaluation of S-Net vs Intel's Concurrent Collections
We present a programming methodology and runtime performance case study
comparing the declarative data flow coordination language S-Net with Intel's
Concurrent Collections (CnC). As a coordination language S-Net achieves a
near-complete separation of concerns between sequential software components
implemented in a separate algorithmic language and their parallel orchestration
in an asynchronous data flow streaming network. We investigate the merits of
S-Net and CnC with the help of a relevant and non-trivial linear algebra
problem: tiled Cholesky decomposition. We describe two alternative S-Net
implementations of tiled Cholesky factorization and compare them with two CnC
implementations, one with explicit performance tuning and one without, that
have previously been used to illustrate Intel CnC. Our experiments on a 48-core
machine demonstrate that S-Net manages to outperform CnC on this problem.Comment: 9 pages, 8 figures, 1 table, accepted for PLC 2014 worksho
On the Expressiveness of Joining
The expressiveness of communication primitives has been explored in a common
framework based on the pi-calculus by considering four features: synchronism
(asynchronous vs synchronous), arity (monadic vs polyadic data), communication
medium (shared dataspaces vs channel-based), and pattern-matching (binding to a
name vs testing name equality vs intensionality). Here another dimension
coordination is considered that accounts for the number of processes required
for an interaction to occur. Coordination generalises binary languages such as
pi-calculus to joining languages that combine inputs such as the Join Calculus
and general rendezvous calculus. By means of possibility/impossibility of
encodings, this paper shows coordination is unrelated to the other features.
That is, joining languages are more expressive than binary languages, and no
combination of the other features can encode a joining language into a binary
language. Further, joining is not able to encode any of the other features
unless they could be encoded otherwise.Comment: In Proceedings ICE 2015, arXiv:1508.04595. arXiv admin note:
substantial text overlap with arXiv:1408.145
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