We investigate the trade-off between performance and power consumption in servers hosting virtual machines running IT services. The performance behavior of such servers is modeled through Generalized Processor Sharing (GPS) queues enhanced with a green speed-scaling mechanism that controls the processing capacity to use depending on the number of active virtual machines. When the number of virt...

The primary motivation for enterprises to adopt virtualization technologies is to create a more agile and dynamic IT infrastructure — with server consolidation, high resource utilization, the ability to quickly add and adjust capacity on demand — while lowering total cost of ownership and responding more effectively to changing business conditions. However, effective management of virtualized I...

For the first time in the literature, the paper considers computational aspects of concave cost virtual private network design problems. It introduces careful bound tightening mechanisms and computationally demonstrate how such bound tightening could impressively improve convex relaxations of the problem. It turns out that, incorporating such bound tightening with a general solution approach co...

Virtual nesting is a popular capacity control strategy in network revenue management. In virtual nesting, products (itineraryfare-class combinations) are mapped (“indexed”) into a relatively small number of “virtual classes” on each resource (flight leg) of the network. Nested protection levels are then used to control the availability of these virtual classes; specifically, a product request i...

To reduce the transmit power while increasing a transmission data rate, authors proposed a wireless multihop virtual cellular network (VCN). Each multi-hop link needs to be allocated a different channel. This means that for the given total number of channels, as the number of hops increases, the number of channels available for each link reduces. However, the signal-to-interference plus noise p...

We investigate the problem of Virtual Path (VP) capacity allocation in a decentralized way. Users (VP controllers), sharing common network resources, are assumed to control their VP capacities according to their performance measures. We formulate a model that differs from previous ones in two points: first, each user has its own performance objective that is simply assumed to be concave and smo...

The author is involved in a multi-year program to establish a number of largescale SME collaboration projects. It was anticipated that some web-based tools used previously could be adapted, but limits in the participant firm capabilities and the emergence of a different business model led to a change in approach. In this paper an adaptation of the notion of absorptive capacity where both a firm...

Motivated by Asynchronous Transfer Mode (ATM) in telecommunication networks, we investigate the problem of designing a directed virtual topology on a directed physical topology, which consists in nding a set of directed virtual paths (VPs) satisfying some constraints in terms of load (the number of VPs sharing a physical link) and hop count (the number of VPs used to establish a connection). Fo...

Hard Disk capacity is increasing all the time. This has brought with it a new problem; the task of locating files is getting harder by the day. Retrieving a document from the myriad of files and directories is no longer an easy task. SemFS integrates searching of files based on metadata as a basic function of the file system. SemFS provides Virtual Directories which list the results of a query....