Declustering is a technique to distribute data sets over multiple disks so that future retrievals can be well balanced over the disks and be performed in parallel. Although disk heterogeneity often exists in systems like clusters, most work on declustering has focused only on homogeneous environments. In this work, we investigate the declustering problem for a heterogeneous disk environment usi...

A two-server resequencing system has two heterogeneous servers and two buffers. One is an arrival buffer, which holds incoming jobs waiting for service. The other is a resequencing buffer, which resequences served jobs back to their arrival orders before departure. Such a system can be modeled as a two-stage tandem queue where the jobs are always kept in the arrival orders but the servers swap ...

An important question in providing on-demand access to large widely shared data files, such as popular video files, is how to effectively use regional (proxy) servers that can store some of the data close to the clients. The proxy caching problem is more complex in the context of continuous media files because of the need to consider bandwidth as well as storage constraints at the proxy servers...

We consider a two-stage tandem queue with single-server first station and multiserver second station. Customers arrive to Station 1 according to a batch Markovian arrival process BMAP . A batch may consist of heterogeneous customers. The type of a customer is determined upon completion of a service at Station 1. The customer’s type is classified based on the number of servers required to proces...

This paper argues that security design for Open Distributed Processing (ODP) would benefit from a shift of focus from the infrastructure to individual servers as the owners and enforcers of security policy. It debates the policy nuances, mechanisms, and protocol design consequences, that would follow from such a change of emphasis. In ODP, physically separate systems federate into heterogeneous...

We consider a single multi-server memoryless service station. Servers have heterogeneous service rates. Arrivals are routed to one of the servers, and the routing decisions are not based on the queue lengths. We consider two criteria for routing selection: the (Nash) equilibrium, under which each customer minimizes his own mean waiting time, given the behavior of the others; and social optimiza...

This paper describes a case study of enhancing the deployment process in J2EE application servers (AS), and more precisely the services building such servers and the applications executing on the servers. We show how, by following a component-based approach to the design of the server, we address the versioning and licensing issues raised by the fact that a J2EE server is built out of heterogen...

We study a tandem queueing network with two stations, M heterogeneous flexible servers, and a finite intermediate buffer. The objective is to dynamically assign the servers to the stations in order to maximize the throughput of the system. The form of the optimal policy for M ≤ 3 was derived in two previous papers. In one of those papers, Andradóttir and Ayhan (Operations Research, Vol. 53, pp....

Digital libraries and OPACs are offering an enormous collection of information resources which can be accessed through Internet by quite different users thanks to the existence of standard protocols for information retrieval such as Z39.50. However, some users may find difficult to get the items they are looking for in such a huge bulk of heterogeneous resources since they have to know where an...

Cloud Computing provides dynamic leasing of server capabilities as a scalable, virtualized service to end users. The discussed work focuses on Infrastructure as a Service (IaaS) model where custom Virtual Machines (VM) are launched in appropriate servers available in a data-center. The context of the environment is a large scale, heterogeneous and dynamic resource pool. Nonlinear variation in t...