Search results for "Distributed computing"
showing 10 items of 622 documents
A resilient distributed measurement system for smart grid application
2020
Since the production of energy from renewable energy sources is strongly increasing, the migration from the classical electric grid toward the smart grid is becoming a reality. Distribution System Operators, along with the control of the entire network and its stability, need to address the security and the reliability of the communication channels and the data itself. In this paper a solution is proposed to address these issues. It is based on a distributed measurement system that relies on a wireless network as well as a redundant Power Line communication system in order to transfer the electrical measures to a centralized SCADA server. The collected data are used to run a power flow algo…
Memory Resource Management for Real-Time Systems
2007
Dynamic memory storage has been widely used for years in computer science. However, its use in real-time systems has not been considered as an important issue, and memory management has not receive much consideration, whereas today's real-time applications are often characterized by highly fluctuating memory requirements. In this paper we present an approach to dynamic memory management for real-time systems. In response to application behavior and requests, the underlying memory management system adjusts resources to meet changing demands and user needs. The architectural framework that realizes this approach allows adaptive allocation of memory resources to applications involving both per…
The differences between distributed shared memory caching and proxy caching
2000
The authors discuss the similarities in caching between the extensively studied distributed shared memory systems and the emerging proxy systems. They believe that several of the techniques used in distributed shared memory systems can be adapted and applied to proxy systems.
Quantized Dissensus in Networks of Agents subject to Death and Duplication
2012
Dissensus is a modeling framework for networks of dynamic agents in competition for scarce resources. Originally inspired by biological cells behaviors, it fits also marketing, finance and many other application areas. Competition is often unstable in the sense that strong agents, those having access to large resources, gain more and more resources at the expense of weak agents. Thus, strong agents duplicate when reaching a critical amount of resources, whereas weak agents die when loosing all their resources. To capture all these phenomena we introduce systems with a discrete time gossip and unstable state dynamics interrupted by discrete events affecting the network topology. Invariancy o…
A Novel Energy Model for MANETs based on Graphs with Activation Windows
2005
Energy usage optimization is still an important issue and a critical design factor for mobile ad hoc networks (MANETs). Only recently a few proposals appeared that consider energy-aware optimizations for routing protocols. In this paper we describe an analytical model for MANETs which is based on graphs with activation windows. The activation windows allow to model the on-off status of the network devices. Moreover, we propose an algorithm with pseudo-polynomial complexity, called STP algorithm (STPA), that based on the current position and state of the nodes determines the shortest time path between the source node and the destination node.
Lifespan-Aware Routing for Wireless Sensor Networks
2010
Wireless Sensor Networks (WSNs) have the capability to become the eyes and ears for the future networked society allowing monitoring of any habitat or object's properties remotely and independently of an energy source. Services based on this technology may change the way we monitor and control remote areas and objects. In this paper we propose a different approach to routing data across Wireless Sensor Networks. We argue that a distance-vector protocol using a lifespan-aware metric is a plausible solution to the task of routing information in WSN in a manner that both saves energy of the individual node and manages summarized energy of the system equally and fairly. The concept is designed …
TBRA: A scalable routing algorithm in highly mobile large scale pure ad hoc wireless mesh networks
2009
In highly mobile pure ad-hoc wireless mesh networks, fast rerouting within low routing discovery delay is a mandatory requirement for routing algorithm to support interactive applications such as VoIP. Also, the communication overhead should be thwarted when networks grow to a large scale. We propose a Tree-Based Routing Algorithm - TBRA to facilitate such two goals. On one hand, TBRA has very low routing discovery delay due to its proactive property. On the other hand, TBRA performs more efficiently than other proactive protocols with respect to low communication overhead, which thanks to its short routing packet length, less numbers and smaller routing table size. Our modeling analysis an…
A flexible and tunable route discovery mechanism for on-demand protocols
2004
Mobile ad-hoc networks are characterized by multihop wireless links and absence of cellular infrastructure. For the last years, routing has been the area under most intensive research. In particular, on-demand routing protocols proposed are extremely attractive due to their low-overhead and efficiency. Currently, wireless ad-hoc networks lack multipath routing protocols. Multipath routing enables increased QoS support, load balancing and enhanced route stability. In this paper we present a new route discovery solution that increases the number of routes found, while reducing the routing overhead when compared to previous proposals. Simulation results show that the additional routing overhea…
Optimal Usage of Multiple Network Connections
2008
In the future mobile networks, a mobile terminal is able to select the best suitable network for each data transmission. The selection of a network connection to be used has been under a lot of study. In this paper, we consider a more extensive case in which we do not select a network connection but use several network connections simultaneously to transfer data. When data is transferred using multiple network connections, a network connection has to be selected for each component of the data. We have modelled this problem as a multiobjective optimization problem and developed a heuristic to solve the problem fast in a static network environment. In this paper, we discuss solving the proble…
Dynamic scheduling of periodic skippable tasks in an overloaded real-time system
2008
International audience; The need for supporting dynamic real-time environments where changes in workloads may occur requires a scheduling framework that explicitly addresses overload conditions, allows the system to achieve graceful degradation and supports a mechanism capable of determining the load to be shed from the system to handle the overload. In applications ranging from video reception to air-craft control, tasks enter periodically and have response time constraints, but missing a deadline is acceptable, provided most deadlines are met. Such tasks are said to be occasionally skippable and have an assigned skip parameter. We look at the problem of uniprocessor scheduling of skippabl…