428,587 research outputs found
Hop and HipHop : Multitier Web Orchestration
Rich applications merge classical computing, client-server concurrency,
web-based interfaces, and the complex time- and event-based reactive
programming found in embedded systems. To handle them, we extend the Hop web
programming platform by HipHop, a domain-specific language dedicated to
event-based process orchestration. Borrowing the synchronous reactive model of
Esterel, HipHop is based on synchronous concurrency and preemption primitives
that are known to be key components for the modular design of complex reactive
behaviors. HipHop departs from Esterel by its ability to handle the dynamicity
of Web applications, thanks to the reflexivity of Hop. Using a music player
example, we show how to modularly build a non-trivial Hop application using
HipHop orchestration code.Comment: International Conference on Distributed Computing and Internet
Technology (2014
Policy-based autonomic control service
Recently, there has been a considerable interest in policy-based, goal-oriented service management and autonomic computing. Much work is still required to investigate designs and policy models and associate meta-reasoning systems for policy-based autonomic systems. In this paper we outline a proposed autonomic middleware control service used to orchestrate selfhealing of distributed applications. Policies are used to adjust the systems autonomy and define self-healing strategies to stabilize/correct a given system in the event of failures
On Asynchronous Session Semantics
This paper studies a behavioural theory of the π-calculus with session types under the fundamental principles of the practice of distributed computing — asynchronous communication which is order-preserving inside each connection (session), augmented with asynchronous inspection of events (message arrivals). A new theory of bisimulations is introduced, distinct from either standard
asynchronous or synchronous bisimilarity, accurately capturing the semantic nature of session-based asynchronously communicating processes augmented with
event primitives. The bisimilarity coincides with the reduction-closed barbed congruence. We examine its properties and compare them with existing semantics.
Using the behavioural theory, we verify that the program transformation of multithreaded into event-driven session based processes, using Lauer-Needham duality,
is type and semantic preserving
Multimedia big data computing for in-depth event analysis
While the most part of ”big data” systems target text-based analytics, multimedia data, which makes up about 2/3 of internet traffic, provide unprecedented opportunities for understanding and responding to real world situations and
challenges. Multimedia Big Data Computing is the new topic
that focus on all aspects of distributed computing systems that
enable massive scale image and video analytics. During the
course of this paper we describe BPEM (Big Picture Event
Monitor), a Multimedia Big Data Computing framework that
operates over streams of digital photos generated by online
communities, and enables monitoring the relationship between
real world events and social media user reaction in real-time.
As a case example, the paper examines publicly available social media data that relate to the Mobile World Congress 2014 that has been harvested and analyzed using the described system.Peer ReviewedPostprint (author's final draft
An Event-Based Approach to Distributed Diagnosis of Continuous Systems
Distributed fault diagnosis solutions are becoming necessary due to the complexity of modern engineering systems, and the advent of smart sensors and computing elements. This paper presents a novel event-based approach for distributed diagnosis of abrupt parametric faults in continuous systems, based on a qualitative abstraction of measurement deviations from the nominal behavior. We systematically derive dynamic fault signatures expressed as event-based fault models. We develop a distributed diagnoser design algorithm that uses these models for designing local event-based diagnosers based on global diagnosability analysis. The local diagnosers each generate globally correct diagnosis results locally, without a centralized coordinator, and by communicating a minimal number of measurements between themselves. The proposed approach is applied to a multi-tank system, and results demonstrate a marked improvement in scalability compared to a centralized approach
Parallel Discrete Event Simulation with Erlang
Discrete Event Simulation (DES) is a widely used technique in which the state
of the simulator is updated by events happening at discrete points in time
(hence the name). DES is used to model and analyze many kinds of systems,
including computer architectures, communication networks, street traffic, and
others. Parallel and Distributed Simulation (PADS) aims at improving the
efficiency of DES by partitioning the simulation model across multiple
processing elements, in order to enabling larger and/or more detailed studies
to be carried out. The interest on PADS is increasing since the widespread
availability of multicore processors and affordable high performance computing
clusters. However, designing parallel simulation models requires considerable
expertise, the result being that PADS techniques are not as widespread as they
could be. In this paper we describe ErlangTW, a parallel simulation middleware
based on the Time Warp synchronization protocol. ErlangTW is entirely written
in Erlang, a concurrent, functional programming language specifically targeted
at building distributed systems. We argue that writing parallel simulation
models in Erlang is considerably easier than using conventional programming
languages. Moreover, ErlangTW allows simulation models to be executed either on
single-core, multicore and distributed computing architectures. We describe the
design and prototype implementation of ErlangTW, and report some preliminary
performance results on multicore and distributed architectures using the well
known PHOLD benchmark.Comment: Proceedings of ACM SIGPLAN Workshop on Functional High-Performance
Computing (FHPC 2012) in conjunction with ICFP 2012. ISBN: 978-1-4503-1577-
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