Antonis Panagakis

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In a delay tolerant network (DTN) the nodes may behave autonomously deciding on their own whether to implement or not the rules of a routing algorithm. In this paper, the effects of node cooperation (or lack of it) are explored for three well-known routing algorithms proposed for DTNs with respect to the message delivery delay and the transmission overhead(More)
The problem of call admission control (CAC) is considered for leaky bucket constrained sessions with deterministic service guarantees (zero loss and finite delay bound) served by a generalized processor sharing scheduler at a single node in the presence of best effort traffic. Based on an optimization process, a CAC algorithm capable of determining the(More)
One of the most widely considered cache replacement policies is Least Recently Used (LRU) based on which many other policies have been developed. LRU has been studied analytically in the literature under the assumption that the object requests are independent. However, such an assumption does not seem to be in agreement with recent studies of Web-traces,(More)
In this paper, a delay tolerant network environment is considered where the source is in full control of the two-hop spreading mechanism by setting key parameters such as the number of copies allowed to be spread in the network and the delay bound of the messages. The analysis allows for a differentiation between the source of the message and the(More)
In this paper the idea that large objects, such as video files, should not be cached or replaced in their entirety, but rather be partitioned in chunks and replacement decisions be applied at the chunk level is examined. It is shown, that a higher byte hit ratio (BHR) can be achieved through partial replacement. The price paid for the improved BHR(More)
Content Distribution has to date been addressed by a mix of centralized and uncoordinated distributed processes, such as server replication and traditional node caching mechanisms, respectively. It is an inherently distributed process that is also increasingly relying on entities that are not only increasingly distributed but also increasingly autonomous.(More)
Recently, the application of the peer to peer networking paradigm (typical for an ad hoc network) has been proposed for wireless local area networks (WLANs), instead of the traditional cellular networking paradigm. In this paper the performance of a WLAN employing the peer to peer networking paradigm is studied via simulations; the results indicate that the(More)
Partial caching of large media objects such as video files has been proposed recently as the caching of entire objects can easily exhaust the storage resources of a proxy server. In this paper the idea of segmenting video files into chunks and applying replacement decisions at the chunk level rather than on entire videos is examined. It is shown that a(More)
In this paper a service discipline, which is based on Generalized Processor Sharing (GPS) and aims to improve resource utilization for deterministic guarantees at a single node is presented. According to the proposed scheme original sessions are decomposed into two components which are treated as separate sessions by a GPS scheduler; the work assigned to(More)