Network virtualization provides the ability to run concurrent virtual networks over a shared substrate. However, it is challenging to design such a platform to host multiple heterogeneous and often highly customized virtual networks. Not only minimal interference among different virtual networks is desired, high-speed packet forwarding is also required. This paper presents Europa, a virtual net...

Background: Spatial learning and navigation is a fundamental cognitive ability consisting of multiple cognitive components. Despite intensive efforts conducted with the assistance of virtual reality technology and functional Magnetic Resonance Imaging (fMRI) modality, the music effect on this cognition and the involved neuronal mechanisms remain elusive. Objectives: We aimed to investigate the...

This paper briefly describes a system that provides a constructive proof of the versatility of ontologies and ontology-based knowledge resources. The Maryland Virtual Patient (MVP) environment models a team of automatic and human agents diagnosing and treating a virtual patient. It uses a uniform ontological substrate to support both the simulation of the world outside the cognitive agents – sp...

In cloud infrastructure, accommodating multiple virtual networks on a single physical network reduces power consumed by physical resources and minimizes cost of operating cloud data centers. However, mapping multiple virtual network resources to physical network components, called virtual network embedding (VNE), is known to be NP-hard. With considering energy efficiency, the problem becomes mo...

Recently network virtualization has been proposed as a promising approach to thwart the current ossification of the Internet by allowing multiple heterogeneous virtual networks (VN) to coexist on a shared infrastructure which itself is controlled by self-interested infrastructure providers. A major challenge in this respect is the VN embedding problem that deals with efficient mapping of virtua...

virtual water adds a new dimension to crop trades and provides a new way of thinking about water scarcity. a systematic analysis of virtual water flows requires integration of all critical drivers of virtual water flows under a single consistent framework. the aim of this study was to assess virtual water flows related to trades of grain crops (wheat, corn, rice, and coarse cereals) and their i...

One of the main objectives of cloud computing providers is increasing the revenue of their cloud datacenters by accommodating virtual network requests as many as possible. However, arrival and departure of virtual network requests fragment physical network’s resources and reduce the possibility of accepting more virtual network requests. To increase the number of virtual network requests accomm...

Nowadays, resource allocation for virtual networks (VNs) is brought as an imperative problem. For the characteristics of virtual networks, multiple virtual networks with different topo can co-exist on a shared infrastructure. A difficult point of problem is how to use the resource effectively and to satisfy the requirement of virtual network request. This problem is NP-hard. In this paper, we i...

With the emergence of Cloud Computing, companies began to adopt it due to its several advantages, such as low initial investment and high scalability. In this context, a provider of Infrastructure as a Service (IaaS) provides computer resources to its clients in a virtualized way. Users can perform requests of virtual machines to deploy and provide their applications. A recent proposal has emer...