Search results for "Distributed"
showing 10 items of 1260 documents
Integration Issues of Distributed Generators Considering Faults in Electrical Distribution Networks
2014
In the recent years there is a great interest in integration of distributed generation (DG) units at distribution level; this integration leads to planning as well as operational challenges. Some possibilities to handle grid planning issues are addressed in this paper. Effects on grid protection, fault current level, and voltage profile are investigated and described for different types of DG units; the classification of DG units is based on their terminal characteristics in terms of real and reactive power delivering capability. Different scenarios for mis-coordination problems caused by DG interconnection are discussed. The effect of the DG on the voltage profile of a distribution network…
Evaluation of the power quality from a seawave power farm for different interconnection schemes
2007
In this paper we present an approach to the interconnection of a seawave power farm to the grid The generator type used in the farm is a Permanent Magnet (PM) linear generator driven from the seawaves that generates, therefore, highly distorted emfs. We propose and compare two possible ways to interconnect the farm to the grid. One is based on an approach where for each generator there is a conversion subsystem that permits the direct connection of each generator to the a.c. network, the other one is based on an ac.-d.c. converter that is connected to the generator, the converter is connected to a dc link that can receive the power from every unit and that can supply a dc-ac converter direc…
Cost-Effective Congestion Management for Interconnection Networks Using Distributed Deterministic Routing
2010
The Interconnection networks are essential elements in current computing systems. For this reason, achieving the best network performance, even in congestion situations, has been a primary goal in recent years. In that sense, there exist several techniques focused on eliminating the main negative effect of congestion: the Head of Line (HOL) blocking. One of the most successful HOL blocking elimination techniques is RECN, which can be applied in source routing networks. FBICM follows the same approach as RECN, but it has been developed for distributed deterministic routing networks. Although FBICM effectively eliminates HOL blocking, it requires too much resources to be implemented. In this …
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…
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…
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.
Internet of Things : a gateway centric solution for providing IoT connectivity
2016
The Internet of Things (IoT) is revolutionising the traditional Internet by extending it with smart everyday objects. Wearables, smart grids and home automation systems are just a few examples of the IoT. A noteworthy point is that the amount of devices connected to the Internet will rapidly grow with the IoT. The IoT typically involves devices that are constrained in terms of energy, memory and processing resources. Therefore, they also limit applying the existing Internet protocols to the IoT. New protocols have been designed for the IoT, all the way from the physical layer, to the application layer. This thesis presents an implementation for an IoT gateway, which enables connectivity to …
Radiation effects on optical frequency domain reflectometry fiber-based sensor
2015
International audience; We investigate the radiation effects on germanosilicate optical fiber acting as the sensing element of optical frequency domain reflectometry devices. Thanks to a new setup permitting to control temperature during irradiation, we evaluate the changes induced by 10 keV x rays on their Rayleigh response up to 1 MGy in a temperature range from −40°C up to 75°C. Irradiation at fixed temperature points out that its measure is reliable during both irradiation and the recovery process. Mixed temperature and radiation measurements show that changing irradiation temperature leads to an error in distributed measurements that depends on the calibration procedure. These results …