Search results for " computing"
showing 10 items of 2075 documents
VEF Traces: A Framework for Modelling MPI Traffic in Interconnection Network Simulators
2015
Simulation is often used to evaluate the behaviour and measure the performance of computing systems. Specifically, in high-performance interconnection networks, the simulation has been extensively considered to verify the behaviour of the network itself and to evaluate its performance. In this context, network simulation must be fed with network traffic, also referred to as network workload, whose nature has been traditionally synthetic. These workloads can be used for the purpose of driving studies on network performance, but often such workloads are not accurate enough if a realistic evaluation is pursued. For this reason, other non-synthetic workloads have gained popularity over last dec…
Efficient Switches with QoS Support for Clusters
2007
Current interconnect standards providing hardware support for quality of service (QoS) consider up to 16 virtual channels (VCs) for this purpose. However, most implementations do not offer so many VCs because they increase the complexity of the switch and the scheduling delays. We have shown that this number of VCs can be significantly reduced, because it is enough to use two VCs for QoS purposes at each switch port. In this paper, we cover the weaknesses of that proposal and, not only we reduce VCs, but we also improve performance due to the flexibility assigning buffer memory.
On the development of a communication-aware task mapping technique
2004
Clusters have become a very cost-effective platform for high-performance computing. In these systems, although currently existing networks actually provide enough bandwidth for the existing applications and workstations, the trend is towards the interconnection network becoming the system bottleneck. Therefore, in the future, scheduling strategies will have to take into account the communication requirements of the applications and the communication bandwidth that the network can offer. One of the key issues in these strategies is the task mapping technique used when the network becomes the system bottleneck.In this paper, we propose a communication-aware mapping technique that tries to mat…
AnyDSL: a partial evaluation framework for programming high-performance libraries
2023
This paper advocates programming high-performance code using partial evaluation. We present a clean-slate programming system with a simple, annotation-based, online partial evaluator that operates on a CPS-style intermediate representation. Our system exposes code generation for accelerators (vectorization/parallelization for CPUs and GPUs) via compiler-known higher-order functions that can be subjected to partial evaluation. This way, generic implementations can be instantiated with target-specific code at compile time. In our experimental evaluation we present three extensive case studies from image processing, ray tracing, and genome sequence alignment. We demonstrate that using partial …
Formal verification of a Cooperative Automatic Repeat reQuest MAC protocol
2012
Author's version of an article published in the journal: Computer Standards & Interfaces. Also available from the publisher at: http://dx.doi.org/10.1016/j.csi.2011.12.001 Cooperative communications, in which a relay node helps the source node to deliver its packets to the destination node, are able to obtain significant benefits in terms of transmission reliability, coverage extension and energy efficiency. A Cooperative Automatic Repeat reQuest (C-ARQ) MAC protocol has been recently proposed to exploit cooperative diversity at the MAC layer. in this paper, we validate the integrity and the validity of the C-ARQ protocol using formal methods. The protocol logic is modeled in SDL and implem…
Autonomous management of Quality of Service and security in an Internet of Things environment
2019
Nowadays, the Internet of Things (IoT) is becoming important in our daily lives thanks to technological advances. This paradigm aims to improve the quality of human life through automating several tasks. In this context, service level guarantee within IoT environments is a major challenge while considering a massive deployment of IoT applications and services as well as extending their usage to different domains. The IoT service level can be characterized in two parts: Quality of Service (QoS) and security. Moreover, this service level must be managed in an autonomic manner within the IoT environment given the heterogeneity and the size of its infrastructure making it difficult, even imposs…
Experimental Analysis of IoT Networks Based on LoRa/LoRaWAN under Indoor and Outdoor EnvirMedusonments: Performance and Limitations
2021
Nowadays, Internet of Things (IoT) has multiple applications in different fields. This concept allows physical devices to connect to the internet in order to establish a strong infrastructure that facilitates many device control and monitoring tasks. Low Power Wide Area (LPWA) communication protocols become widely used for IoT networks because of their low power consumption and the broad range communication. LPWA enables devices to transmit small amounts of data in a long distance. Among LPWA protocols, LoRa technology gained a lot of interest recently from the research community and many companies. LoRa is a long range and low power wireless communication technology regulated by the LoRaWA…
Distributed estimation and control of water distribution networks by logical consensus
2014
In this study we present a methodology for backflow detec- tion through the interpretation of results from a network of Automatic Meter Reading. The approach is based on the so– called logical consensus theory and consists of a distributed failure detection and system reconfiguration. The effective- ness of the proposed method is showed through simulation within a prototypical water distribution network.
PGAC: A Parallel Genetic Algorithm for Data Clustering
2005
Cluster analysis is a valuable tool for exploratory pattern analysis, especially when very little a priori knowledge about the data is available. Distributed systems, based on high speed intranet connections, provide new tools in order to design new and faster clustering algorithms. Here, a parallel genetic algorithm for clustering called PGAC is described. The used strategy of parallelization is the island model paradigm where different populations of chromosomes (called demes) evolve locally to each processor and from time to time some individuals are moved from one deme to another. Experiments have been performed for testing the benefits of the parallelisation paradigm in terms of comput…
An Intra-Subject Approach Based on the Application of HMM to Predict Concentration in Educational Contexts from Nonintrusive Physiological Signals in…
2021
Previous research has proven the strong influence of emotions on student engagement and motivation. Therefore, emotion recognition is becoming very relevant in educational scenarios, but there is no standard method for predicting students’ affects. However, physiological signals have been widely used in educational contexts. Some physiological signals have shown a high accuracy in detecting emotions because they reflect spontaneous affect-related information, which is fresh and does not require additional control or interpretation. Most proposed works use measuring equipment for which applicability in real-world scenarios is limited because of its high cost and intrusiveness. To tackle this…