981 resultados para Virtual Networks


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In a world that is increasingly dominated by the Internet, there is a growing demand for low cost access at the users convenience. The expansion of wireless Internet networks, in particular unsecured wireless Internet networks, gives rise to novel challenges for the regulation of Internet access. The ability to access unsecured wireless Internet networks with ease and with very little impact upon the owner of the network suggests that such 'piggybacking' may be criminal behaviour or may amount to an actionable civil wrong. This paper will explore the legal ramifications of piggybacking an unsecured wireless network with knowledge that there is no entitlement to the use of the network and will consider what Australian authorities should do about this situation. This paper will look at the position in Australia and juxtapose this with that of the United Kingdom and the United States of America. In both the United Kingdom and the United States of America prosecutions have taken place of individuals who knowingly accessed unsecured wireless
networks for their own personal use.

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In this paper we studied several virtual routing structures (ring, ring-tree, cord, and mesh) which are scalable, independent on addresses, based on local information and partial global information for routing packets. These virtual routing structures are built on the top of the backbone nodes which are selected by considering power, connections, and immobility metrics.Our experimental results on the ns2 simulator and both TelosBand MicaZ sensor nodes tested platform prove that the virtual backbone structures are superior to the existing routing schemes and the different virtual structures fit in with the different physical scenarios.

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Our research examines how the organisational structure facilitates knowledge sharing within the group. This case study examines a Victorian regional sustainable group using interviews and social network analysis to identify the group’s organisational structure and its effect on knowledge sharing between the members. Our findings indicate that while the mixed membership, lack of hierarchy and layered structure are complex, these elements work together to provide members with a rich body of knowledge. The diversity and differences in membership are complimentary and combined can provide a more in-depth understanding of the regional sustainable development issues.

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With the advent of social networks, it became apparent that the social aspect of designing and learning plays a crucial role in students’ education. The ease of communication, leadership opportunity, democratic interaction, teamwork, and the sense of community are some of the aspects that are now in the centre of design interaction. Online interactions, multimedia, mobile computing and face-to-face learning create blended learning environments to which some Virtual Design Studios (VDS) have reacted. On the sample of a design studio at Deakin University the paper discusses details of the Social Network VDS, its pedagogical implications to PBL, and presents how it is successful in empowering architectural students to collaborate and communicate design proposals that integrate a variety of skills, deep learning, and construction of knowledge. It studies the effectiveness of the generated social intelligence and explores the facilitation of students’ self-directed learning. Hereby the paper studies the construction of knowledge via social interaction and how blended learning environments foster motivation and information exchange.

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The bandwidth requirements of the Internet are increasing every day and there are newer and more bandwidth-thirsty applications emerging on the horizon. Wavelength division multiplexing (WDM) is the next step towards leveraging the capabilities of the optical fiber, especially for wide-area backbone networks. The ability to switch a signal at intermediate nodes in a WDM network based on their wavelengths is known as wavelength-routing. One of the greatest advantages of using wavelength-routing WDM is the ability to create a virtual topology different from the physical topology of the underlying network. This virtual topology can be reconfigured when necessary, to improve performance. We discuss the previous work done on virtual topology design and also discuss and propose different reconfiguration algorithms applicable under different scenarios.

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Network survivability is one of the most important issues in the design of optical WDM networks. In this work we study the problem of survivable routing of a virtual topology on a physical topology with Shared Risk Link Groups (SRLG). The survivable virtual topology routing problem against single-link failures in the physical topology is proved to be NP-complete in [1]. We prove that survivable virtual topology routing problem against SRLG/node failures is also NP-complete. We present an improved integer linear programming (ILP) formulation (in comparison to [1]) for computing the survivable routing under SRLG/node failures. Using an ILP solver, we computed the survivable virtual topology routing against link and SRLG failures for small and medium sized networks efficiently. As even our improved ILP formulation becomes intractable for large networks, we present a congestion-based heuristic and a tabu search heuristic (which uses the congestion-based heuristic solution as the initial solution) for computing survivable routing of a virtual topology. Our experimental results show that tabu search heuristic coupled with the congestion based heuristic (used as initial solution) provides fast and near-optimal solutions.

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An analytical model for Virtual Topology Reconfiguration (VTR) in optical networks is developed. It aims at the optical networks with a circuit-based data plane and an IPlike control plane. By identifying and analyzing the important factors impacting the network performance due to VTR operations on both planes, we can compare the benefits and penalties of different VTR algorithms and policies. The best VTR scenario can be adaptively chosen from a set of such algorithms and policies according to the real-time network situations. For this purpose, a cost model integrating all these factors is created to provide a comparison criterion independent of any specific VTR algorithm and policy. A case study based on simulation experiments is conducted to illustrate the application of our models.

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Abstract Cloud computing service emerged as an essential component of the Enterprise {IT} infrastructure. Migration towards a full range and large-scale convergence of Cloud and network services has become the current trend for addressing requirements of the Cloud environment. Our approach takes the infrastructure as a service paradigm to build converged virtual infrastructures, which allow offering tailored performance and enable multi-tenancy over a common physical infrastructure. Thanks to virtualization, new exploitation activities of the physical infrastructures may arise for both transport network and Data Centres services. This approach makes network and Data Centres’ resources dedicated to Cloud Computing to converge on the same flexible and scalable level. The work presented here is based on the automation of the virtual infrastructure provisioning service. On top of the virtual infrastructures, a coordinated operation and control of the different resources is performed with the objective of automatically tailoring connectivity services to the Cloud service dynamics. Furthermore, in order to support elasticity of the Cloud services through the optical network, dynamic re-planning features have been provided to the virtual infrastructure service, which allows scaling up or down existing virtual infrastructures to optimize resource utilisation and dynamically adapt to users’ demands. Thus, the dynamic re-planning of the service becomes key component for the coordination of Cloud and optical network resource in an optimal way in terms of resource utilisation. The presented work is complemented with a use case of the virtual infrastructure service being adopted in a distributed Enterprise Information System, that scales up and down as a function of the application requests.

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Network building and exchange of information by people within networks is crucial to the innovation process. Contrary to older models, in social networks the flow of information is noncontinuous and nonlinear. There are critical barriers to information flow that operate in a problematic manner. New models and new analytic tools are needed for these systems. This paper introduces the concept of virtual circuits and draws on recent concepts of network modelling and design to introduce a probabilistic switch theory that can be described using matrices. It can be used to model multistep information flow between people within organisational networks, to provide formal definitions of efficient and balanced networks and to describe distortion of information as it passes along human communication channels. The concept of multi-dimensional information space arises naturally from the use of matrices. The theory and the use of serial diagonal matrices have applications to organisational design and to the modelling of other systems. It is hypothesised that opinion leaders or creative individuals are more likely to emerge at information-rich nodes in networks. A mathematical definition of such nodes is developed and it does not invariably correspond with centrality as defined by early work on networks.

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The use of virtual social networks (VSNs) has been prevalent among consumers worldwide. Numerous studies have investigated various aspects of VSNs. However, these studies have mainly focused on students and young adults as they were early adopters of these innovative networks. A search of the literature revealed there has been a paucity of research on adult consumers’ use of VSNs. This research study addressed this gap in the literature by examining the determinants of engagement in VSNs among adult consumers in Singapore. The objectives of this study are to empirically investigate the determinants of engagement in VSNs and to offer theoretical insights into consumers’ preference and usage of VSNs. This study tapped upon several theories developed in the discipline of technology and innovation adoption. These were Roger’s Diffusion of Innovation, Theory of Reasoned Action (TRA), Theory of Planned Behavior (TPB), Technology Acceptance Model (TAM), Conceptual Framework of Individual Innovation Adoption by Frambach and Schillewaert (2002), Enhanced Model of Innovation Adoption by Talukder (2011), Extended Unified Theory of Acceptance and Use of Technology (UTAUT2) and the Information Systems (IS) Success Model. The proposed research model, named the Media Usage Model (MUM), is a framework rooted in innovation diffusion and IS theories. The MUM distilled the essence of these established models and thus provides an updated, lucid explanation of engagement in VSNs. A cross-sectional, online social survey was conducted to collect quantitative data to examine the validity of the proposed research model. Multivariate data analysis was carried out on a data set comprising 806 usable responses by utilizing SPSS, and for structural equation modeling AMOS and SmartPLS. The results indicate that consumer attitude towards VSNs is significantly and positively influenced by: three individual factors – hedonic motivation, incentives and experience; two system characteristics – system quality and information quality; and one social factor – social bonding. Consumer demographics were found to influence people’s attitudes towards VSNs. In addition, consumer experience and attitude towards VSNs significantly and positively influence their usage of VSNs. The empirical data supported the proposed research model, explaining 80% of variance in attitude towards VSNs and 45% of variance in usage of VSNs. Therefore, the MUM achieves a definite contribution to theoretical knowledge of consumer engagement in VSNs by deepening and broadening our appreciation of the intricacies related to use of VSNs in Singapore. This study’s findings have implications for customer service management, services marketing and consumer behavior. These findings also have strategic implications for maximizing efficient utilization and effective management of VSNs by businesses and operators. The contributions of this research are: firstly, shifting the boundaries of technology or innovation adoption theories from research on employees to consumers as well as the boundaries of Internet usage or adoption research from students to adults, which is also known as empirical generalization; secondly, highlighting the issues associated with lack of significance of social factors in adoption research; and thirdly, augmenting information systems research by integrating important antecedents for success in information systems.

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The innovation diffusion and knowledge management literature strongly supports the importance of communities of practice (COP) for enabling knowledge about how to use and adopt innovation initiatives. One of the most powerful tools for innovation diffusion is word-of-mouth wisdom from committed individuals who mentor and support each other. Close proximity for face-to-face interaction is highly effective, however, many organisations are geographically dispersed with projects being virtual linked sub-organisations using ICT to communicate. ICT has also introduced a useful facilitating technology for developing knowledge networks. This paper presents findings from a research program concentrating on ICT innovation diffusion in the Australian construction industry. One way in which ICT diffusion is taking place was found to be through within-company communities of practice. We undertook in-depth unstructured interviews with three of the major 10 to 15 contractors in Australia to discuss their ICT diffusion strategies. We discovered that in all three cases,within company networked communities of practice was a central strategy. Further, effective diffusion of ICT groupware tools can be critical in developing COP where they are geographically dispersed.

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This paper introduces friendwork as a new term in social networks studies. A friendwork is a network of friends. It is a specific case of an interpersonal social network. Naming this seemingly well known and familiar group of people as a friendwork facilitates its differentiation from the overall social network, while highlighting this subgroup's specific attributes and dynamics. The focus on one segment within social networks stimulates a wider discussion regarding the different subgroups within social networks. Other subgroups also discussed in this paper are: family dependent, work related, location based and virtual acquaintances networks. This discussion informs a larger study of social media, specifically addressing interactive communication modes that are in use within friendworks: direct (face-to-face) and mediated (mainly fixed telephone, internet and mobile phone). It explores the role of social media within friendworks while providing a communication perspective on social networks.

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Network-based Intrusion Detection Systems (NIDSs) analyse network traffic to detect instances of malicious activity. Typically, this is only possible when the network traffic is accessible for analysis. With the growing use of Virtual Private Networks (VPNs) that encrypt network traffic, the NIDS can no longer access this crucial audit data. In this paper, we present an implementation and evaluation of our approach proposed in Goh et al. (2009). It is based on Shamir's secret-sharing scheme and allows a NIDS to function normally in a VPN without any modifications and without compromising the confidentiality afforded by the VPN.