An empirical study of memory sharing in virtual machines

Content-based page sharing is a technique often used in virtualized environments to reduce server memory requirements. Many systems have been proposed to capture the benefits of page sharing. However, there have been few analyses of page sharing in general, both considering its real-world utility and typical sources of sharing potential. We provide insight into this issue through an exploration and analysis of memory traces captured from real user machines and controlled virtual machines. First, we observe that absolute sharing levels (excluding zero pages) generally remain under 15%, contrasting with prior work that has often reported savings of 30% or more. Second, we find that sharing within individual machines often accounts for nearly all (\u3e90%) of the sharing potential within a set of machines, with inter-machine sharing contributing only a small amount. Moreover, even small differences between machines significantly reduce what little inter-machine sharing might otherwise be possible. Third, we find that OS features like address space layout randomization can further diminish sharing potential. These findings both temper expectations of real-world sharing gains and suggest that sharing efforts may be equally effective if employed within the operating system of a single machine, rather than exclusively targeting groups of virtual machines

Design Considerations for Virtual Classroom and Laboratory Environments

With the ever-increasing demand for distance education one of the key challenges facing faculty is not only delivering effective instruction through both lecture-style and laboratory means, but also giving students an environment with a sense of presence. The key challenge here is to improve on the distance student‟s capabilities for interaction and collaboration thereby enhancing their ability to work in more group and team settings. In short, virtual environments present distance students with exciting new forums for meeting and sharing their thoughts and ideas in real-time. Today‟s virtual environments like Second Life (SL) provide students with open-ended opportunities for exploration and invention. This has broad reaching implications for faculty, and allows for the delivery of course content in stimulating and highly engaging manners. However, before these virtual environments can be implemented as academic tools, virtual spaces in the form of classrooms and laboratories need to be designed and developed to facilitate student and faculty interaction. This effort describes considerations made when designing some of the early virtual classroom and laboratory spaces developed within a newly established virtual campus. Once these spaces were built, class sessions were conducted and the students were surveyed in order to document their first impressions of the experience. Finally, the survey responses are analyzed and consideration is made for the establishment of design criteria for further virtual site development

A multi-service multi-role integrated information model for dynamic resource discovery in virtual networks

Network virtualization is considered as a promising way to overcome the limitations and fight the gradual ossification of the current Internet infrastructure. The network virtualization concept consists in the dynamic creation of several co-existing logical network instances (or virtual networks) over a shared physical network infrastructure. One of the challenges associated with this concept is the dynamic discovery and selection of virtual resources that can be composed to form virtual networks. To achieve that task, there is a need for a formal and expressive information model facilitating information representation and sharing between the various roles/entities involved. We have previously proposed a service-oriented hierarchical business model for virtual networking environments, as well as an architecture enabling its realization. In this paper, we build on this business model and architecture by proposing a multi-service, multi-role hierarchical information model, for virtual networking environments. Furthermore, we demonstrate the usage of this information model using a secure content distribution scenario that is realized using REST interfaces. Unlike other proposals, our integrated information model enables the fine-grained description of virtual networks and virtual networking resources, in addition to the modeling of network services and roles, and their relationships and hierarchy. © 2013 IEEE

A Global Information World.

The users who create and edit topical Wikipedia articles (e.g., Miss Piggy ) or subject-focused Wikia articles (e.g., all things Muppets related) form stronger community bonds than those who are just readers. While major search engines offer video search, Kassel cited some new to me, including TeacherTube ( geared toward teachers and students for community sharing for instructional videos ) and Vidipedia ( structured like Wikipedia but with video content ). David Ball, university librarian, Bournemouth University, UK, said academic libraries face obstacles when virtual learning environments (VLEs) become the primary means of interaction between students and universities

Virtual knowledge brokering : describing the roles and strategies used by knowledge brokers in a pediatric physiotherapy virtual community of practice

Introduction: Knowledge transfer in pediatric rehabilitation is challenging and requires active, multifaceted strategies. The use of knowledge brokers (KBs) is one such strategy noted to promote clinician behavior change. The success of using KBs to transfer knowledge relies on their ability to adapt to ever-changing clinical contexts. In addition, with the rapid growth of online platforms as knowledge transfer forums, KBs must become effective in virtual environments. Although the role of KBs has been studied in various clinical contexts, their emerging role in specific online environments designed to support evidence-based behavior change has not yet been described. Our objective is to describe the roles of, and strategies used by, four KBs involved in a virtual community of practice to guide and inform future online KB interventions. Methods: A descriptive design guided this study and a thematic content analysis process was used to analyze online KB postings. The Promoting Action on Research in Health Sciences knowledge transfer framework and online andragogical learning theories assisted in the coding. A thematic map was created illustrating the links between KBs' strategies and emerging roles in the virtual environment. Results: We analyzed 95 posts and identified three roles: 1) context architect: promoting a respectful learning environment, 2) knowledge sharing promoter: building capacity, and 3) linkage creator: connecting research-to-practice. Strategies used by KBs reflected invitational, constructivism, and connectivism approaches, with roles and strategies changing over time. Discussion: This study increases our understanding of the actions of KBs in virtual contexts to foster uptake of research evidence in pediatric physiotherapy. Our results provide valuable information about the knowledge and skills required by individuals to fulfill this role in virtual environments

Stochastic Models for Planning VLE Moodle Environments based on Containers and Virtual Machines

Moodle Virtual Learning Environments (VLEs) represent tools of a pedagogical dimension where the teacher uses various resources to stimulate student learning. Content presented in hypertext, audio or vídeo formats can be adopted as a means to facilitate the learning. These platforms tend to produce high processing rates on servers, large volumes of data on the network and, consequently, degrade performance, increase energy consumption and costs. However, to provide eficiente sharing of computing resources and at the same time minimize financial costs, these VLE platforms typically run on virtualized infrastructures such as Virtual Machines (VM) or containers, which have advantages and disadvantages. Stochastic models, such as stochastic Petri nets (SPNs), can be used in the modeling and evaluation of such environments. Therefore, this work aims to use analytical modeling through SPNs to assess the performance, energy consumption and cost of environments based on containers and VMs. Metrics such as throughput, response time, energy consumption and cost are collected and analyzed. The results revealed that, for example, a cluster with 10 replicas, occupied at their maximum capacity, can generate a 46.54% reduction in energy consumption if containers are used. Additionally, we validate the accuracy of the analytical models by comparing their results with the results obtained in a real infrastructure

The use of virtual environments as an extended classroom – A case study with adult learners in tertiary education

This study was conducted in immersive 3D virtual environment Second Life®, with the support of web 2.0 tools as a complement to physical classroom - extended classroom. It was assumed that socialization is a key factor for collaborative learning and knowledge construction. The study aims to identify the variables that may influence knowledge sharing in learning contexts using virtual environments; with the aim of contributing to the improvement of learning situations using the online tools. This research is exploratory in nature and falls within the field of phenomenological studies. The study was implemented in a tertiary education institution involving regular and adult learners. We conclude that in virtual environments learners tend to feel more confident, open, participatory, creative, understanding and seem to participate in training sessions because they are indeed interested in learning. On the other hand, the possibility of providing online tutorial session allows reaching a larger number of learners. These online sessions can be established in a time and place (virtual) free of constraints and can be tailored, allowing a more effective participation from learners.info:eu-repo/semantics/publishedVersio

A literature review of the use of Web 2.0 tools in Higher Education

This review focuses on the use of Web 2.0 tools in Higher Education. It provides a synthesis of the research literature in the field and a series of illustrative examples of how these tools are being used in learning and teaching. It draws out the perceived benefits that these new technologies appear to offer, and highlights some of the challenges and issues surrounding their use. The review forms the basis for a HE Academy funded project, ‘Peals in the Cloud’, which is exploring how Web 2.0 tools can be used to support evidence-based practices in learning and teaching. The project has also produced two in-depth case studies, which are reported elsewhere (Galley et al., 2010, Alevizou et al., 2010). The case studies focus on evaluation of a recently developed site for learning and teaching, Cloudworks, which harnesses Web 2.0 functionality to facilitate the sharing and discussion of educational practice. The case studies aim to explore to what extent the Web 2.0 affordances of the site are successfully promoting the sharing of ideas, as well as scholarly reflections, on learning and teaching

Shared visiting in Equator city

In this paper we describe an infrastructure and prototype system for sharing of visiting experiences across multiple media. The prototype supports synchronous co-visiting by physical and digital visitors, with digital access via either the World Wide Web or 3-dimensional graphics

Reflections on the use of Project Wonderland as a mixed-reality environment for teaching and learning

This paper reflects on the lessons learnt from MiRTLE?a collaborative research project to create a ?mixed reality teaching and learning environment? that enables teachers and students participating in real-time mixed and online classes to interact with avatar representations of each other. The key hypothesis of the project is that avatar representations of teachers and students can help create a sense of shared presence, engendering a greater sense of community and improving student engagement in online lessons. This paper explores the technology that underpins such environments by presenting work on the use of a massively multi-user game server, based on Sun?s Project Darkstar and Project Wonderland tools, to create a shared teaching environment, illustrating the process by describing the creation of a virtual classroom. It is planned that the MiRTLE platform will be used in several trial applications ? which are described in the paper. These example applications are then used to explore some of the research issues arising from the use of virtual environments within an education environment. The research discussion initially focuses on the plans to assess this within the MiRTLE project. This includes some of the issues of designing virtual environments for teaching and learning, and how supporting pedagogical and social theories can inform this process