876 resultados para Online dating networks
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Online travel reviews are emerging as a powerful source of information affecting tourists' pre-purchase evaluation of a hotel organization. This trend has highlighted the need for a greater understanding of the impact of online reviews on consumer attitudes and behaviors. In view of this need, we investigate the influence of online hotel reviews on consumers' attributions of service quality and firms' ability to control service delivery. An experimental design was used to examine the effects of four independent variables: framing; valence; ratings; and target. The results suggest that in reviews evaluating a hotel, remarks related to core services are more likely to induce positive service quality attributions. Recent reviews affect customers' attributions of controllability for service delivery, with negative reviews exerting an unfavorable influence on consumers' perceptions. The findings highlight the importance of managing the core service and the need for managers to act promptly in addressing customer service problems.
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This thesis examines online spoof videos in China. It shows the relationship between user-created content and change and how such videos are impacting on social memory. In the West, we are witnessing two outstanding trends in media. On the one hand, media are turning more "demotic" (Turner, 2006) and "participatory" (Jenkins, 2006), whereby lay audiences use popular media for identity formation, representation and association, reconfiguring the media and cultural landscape, and rendering invalid the old paradigm based on the dichotomy of audience and author, creator and consumer, expert and amateur. On the other hand, in both mainstream media and user-creation online there is a trend towards "silly citizenship", with comedy, send-ups and spoofs that used to reside in the margin propelled to the central stage in both pleasure and politics (Hartley, 2010), as is shown in the rising popularity of the Daily Show, Colbert Report, and spoof videos in elections ,e.g. the 2008 presidential election in US (Gray, Jones, & Thompson, 2009; Tryon, 2008). User generated content—and spoof subcultures—is now much a debated phenomenon in China. However, with different political (one party rule and censorship) and cultural (media regarded mainly as instrument for education and social stabilization instead of a critical fourth estate) configurations, will the social and cultural impacts of the two trends in the West be as the same in China? If not, what will be the specificities in the China context? The project starts with a historical review of popular culture and user-created content in China, before turning to spoof videos and looking at how they are produced and shared, travel and diffused on the Internet, and how the communities and sub-cultures forming and emerging around spoof videos are changing the overall cultural landscape in China. By acting as a participant observer in online video sharing sites and conducting face-to face as well as online interviews, I identify lead users and creators of spoof videos and the social networks emerging around them. I call these lead users "skill hubs" and their networks "liquid communities", foregrounding the fact that their appeal doesn’t come from their amicable personality, but rather from their creative skills; and that the networks surrounding them are in a permanent flux, with members coming and going as they see fit. I argue that the "liquidness" (Bauman, 2000) of these communities is what makes them constantly creative and appealing. Textual analysis of online videos, their comments and derivatives are conducted to tease out the uses that that can be made of spoof videos, namely as phatic communication, as alternative memory and as political engagement. Through these analyses I show that spoof videos constitute not only a space where young generations can engage with each other, communicate their anger and dissatisfaction, fun and hope, and where they participate in socio-cultural and political debates, but also create a space where they can experiment with their new skills, new ideas, and new citizenship. The rise of spoof videos heralds the beginning of a trend in popular culture in contemporary China towards the "canonization of the jester" and the dethroning of the establishment. I also argue that a historical perspective is needed to understand the current surge of use creativity and user activism in China, and that many forms of popular media we experience today have their antecedents in various stages of Chinese history. The entrenched "control-resistance" binary is inadequate in interpreting the rich, flux and multilayered Internet space in China.
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The actin microfilament plays a critical role in many cellular processes including embryonic development, wound healing, immune response, and tissue development. It is commonly organized in the form of networks whose mechanical properties change with changes in their architecture due to cell evolution processes. This paper presents a new nonlinear continuum mechanics model of single filamentous actin (F-actin) that is based on nanoscale molecular simulations. Following this continuum model of the single F-actin, mechanical properties of differently architected lamellipodia are studied. The results provide insight that can contribute to the understanding of the cell edge motions of living cells.
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Computer worms represent a serious threat for modern communication infrastructures. These epidemics can cause great damage such as financial losses or interruption of critical services which support lives of citizens. These worms can spread with a speed which prevents instant human intervention. Therefore automatic detection and mitigation techniques need to be developed. However, if these techniques are not designed and intensively tested in realistic environments, they may cause even more harm as they heavily interfere with high volume communication flows. We present a simulation model which allows studies of worm spread and counter measures in large scale multi-AS topologies with millions of IP addresses.
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Reasoning with uncertain knowledge and belief has long been recognized as an important research issue in Artificial Intelligence (AI). Several methodologies have been proposed in the past, including knowledge-based systems, fuzzy sets, and probability theory. The probabilistic approach became popular mainly due to a knowledge representation framework called Bayesian networks. Bayesian networks have earned reputation of being powerful tools for modeling complex problem involving uncertain knowledge. Uncertain knowledge exists in domains such as medicine, law, geographical information systems and design as it is difficult to retrieve all knowledge and experience from experts. In design domain, experts believe that design style is an intangible concept and that its knowledge is difficult to be presented in a formal way. The aim of the research is to find ways to represent design style knowledge in Bayesian net works. We showed that these networks can be used for diagnosis (inferences) and classification of design style. The furniture design style is selected as an example domain, however the method can be used for any other domain.
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University learning increasingly includes online learning experiences embedded within teaching with the dual policy intentions of increasing flexibility and learner engagement. In this research project, three university lecturers from different teaching contexts selected technologies for online learning to enhance learner engagement by encouraging peer learning. A sociocultural view of learning was used to conceptualise the technological and social affordances that might enable student peer participation and engagement. The research explored the question: “What are the benefits and barriers experienced by students engaging in online peer collaboration?” Students reported benefits including a sense of belonging that enhanced motivation, and professional identity. This article also reports on some of the challenges for students and University academics when engaging in online learning communities.
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Advances in technology introduce new application areas for sensor networks. Foreseeable wide deployment of mission critical sensor networks creates concerns on security issues. Security of large scale densely deployed and infrastructure less wireless networks of resource limited sensor nodes requires efficient key distribution and management mechanisms. We consider distributed and hierarchical wireless sensor networks where unicast, multicast and broadcast type of communications can take place. We evaluate deterministic, probabilistic and hybrid type of key pre-distribution and dynamic key generation algorithms for distributing pair-wise, group-wise and network-wise keys.
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We consider the problem of how to maximize secure connectivity of multi-hop wireless ad hoc networks after deployment. Two approaches, based on graph augmentation problems with nonlinear edge costs, are formulated. The first one is based on establishing a secret key using only the links that are already secured by secret keys. This problem is in NP-hard and does not accept polynomial time approximation scheme PTAS since minimum cutsets to be augmented do not admit constant costs. The second one is based of increasing the power level between a pair of nodes that has a secret key to enable them physically connect. This problem can be formulated as the optimal key establishment problem with interference constraints with bi-objectives: (i) maximizing the concurrent key establishment flow, (ii) minimizing the cost. We show that both problems are NP-hard and MAX-SNP (i.e., it is NP-hard to approximate them within a factor of 1 + e for e > 0 ) with a reduction to MAX3SAT problem. Thus, we design and implement a fully distributed algorithm for authenticated key establishment in wireless sensor networks where each sensor knows only its one- hop neighborhood. Our witness based approaches find witnesses in multi-hop neighborhood to authenticate the key establishment between two sensor nodes which do not share a key and which are not connected through a secure path.
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Key distribution is one of the most challenging security issues in wireless sensor networks where sensor nodes are randomly scattered over a hostile territory. In such a sensor deployment scenario, there will be no prior knowledge of post deployment configuration. For security solutions requiring pair wise keys, it is impossible to decide how to distribute key pairs to sensor nodes before the deployment. Existing approaches to this problem are to assign more than one key, namely a key-chain, to each node. Key-chains are randomly drawn from a key-pool. Either two neighbouring nodes have a key in common in their key-chains, or there is a path, called key-path, among these two nodes where each pair of neighbouring nodes on this path has a key in common. Problem in such a solution is to decide on the key-chain size and key-pool size so that every pair of nodes can establish a session key directly or through a path with high probability. The size of the key-path is the key factor for the efficiency of the design. This paper presents novel, deterministic and hybrid approaches based on Combinatorial Design for key distribution. In particular, several block design techniques are considered for generating the key-chains and the key-pools. Comparison to probabilistic schemes shows that our combinatorial approach produces better connectivity with smaller key-chain sizes.
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Secure communications in distributed Wireless Sensor Networks (WSN) operating under adversarial conditions necessitate efficient key management schemes. In the absence of a priori knowledge of post-deployment network configuration and due to limited resources at sensor nodes, key management schemes cannot be based on post-deployment computations. Instead, a list of keys, called a key-chain, is distributed to each sensor node before the deployment. For secure communication, either two nodes should have a key in common in their key-chains, or they should establish a key through a secure-path on which every link is secured with a key. We first provide a comparative survey of well known key management solutions for WSN. Probabilistic, deterministic and hybrid key management solutions are presented, and they are compared based on their security properties and re-source usage. We provide a taxonomy of solutions, and identify trade-offs in them to conclude that there is no one size-fits-all solution. Second, we design and analyze deterministic and hybrid techniques to distribute pair-wise keys to sensor nodes before the deployment. We present novel deterministic and hybrid approaches based on combinatorial design theory and graph theory for deciding how many and which keys to assign to each key-chain before the sensor network deployment. Performance and security of the proposed schemes are studied both analytically and computationally. Third, we address the key establishment problem in WSN which requires key agreement algorithms without authentication are executed over a secure-path. The length of the secure-path impacts the power consumption and the initialization delay for a WSN before it becomes operational. We formulate the key establishment problem as a constrained bi-objective optimization problem, break it into two sub-problems, and show that they are both NP-Hard and MAX-SNP-Hard. Having established inapproximability results, we focus on addressing the authentication problem that prevents key agreement algorithms to be used directly over a wireless link. We present a fully distributed algorithm where each pair of nodes can establish a key with authentication by using their neighbors as the witnesses.
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Widespread adoption by electricity utilities of Non-Conventional Instrument Transformers, such as optical or capacitive transducers, has been limited due to the lack of a standardised interface and multi-vendor interoperability. Low power analogue interfaces are being replaced by IEC 61850 9 2 and IEC 61869 9 digital interfaces that use Ethernet networks for communication. These ‘process bus’ connections achieve significant cost savings by simplifying connections between switchyard and control rooms; however the in-service performance when these standards are employed is largely unknown. The performance of real-time Ethernet networks and time synchronisation was assessed using a scale model of a substation automation system. The test bed was constructed from commercially available timing and protection equipment supplied by a range of vendors. Test protocols have been developed to thoroughly evaluate the performance of Ethernet networks and network based time synchronisation. The suitability of IEEE Std 1588 Precision Time Protocol (PTP) as a synchronising system for sampled values was tested in the steady state and under transient conditions. Similarly, the performance of hardened Ethernet switches designed for substation use was assessed under a range of network operating conditions. This paper presents test methods that use a precision Ethernet capture card to accurately measure PTP and network performance. These methods can be used for product selection and to assess ongoing system performance as substations age. Key findings on the behaviour of multi-function process bus networks are presented. System level tests were performed using a Real Time Digital Simulator and transformer protection relay with sampled value and Generic Object Oriented Substation Events (GOOSE) capability. These include the interactions between sampled values, PTP and GOOSE messages. Our research has demonstrated that several protocols can be used on a shared process bus, even with very high network loads. This should provide confidence that this technology is suitable for transmission substations.
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In practical cases for active noise control (ANC), the secondary path has usually a time varying behavior. For these cases, an online secondary path modeling method that uses a white noise as a training signal is required to ensure convergence of the system. The modeling accuracy and the convergence rate are increased when a white noise with a larger variance is used. However, the larger variance increases the residual noise, which decreases performance of the system and additionally causes instability problem to feedback structures. A sudden change in the secondary path leads to divergence of the online secondary path modeling filter. To overcome these problems, this paper proposes a new approach for online secondary path modeling in feedback ANC systems. The proposed algorithm uses the advantages of white noise with larger variance to model the secondary path, but the injection is stopped at the optimum point to increase performance of the algorithm and to prevent the instability effect of the white noise. In this approach, instead of continuous injection of the white noise, a sudden change in secondary path during the operation makes the algorithm to reactivate injection of the white noise to correct the secondary path estimation. In addition, the proposed method models the secondary path without the need of using off-line estimation of the secondary path. Considering the above features increases the convergence rate and modeling accuracy, which results in a high system performance. Computer simulation results shown in this paper indicate effectiveness of the proposed method.
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A global, online quantitative study among 300 consumers of digital technology products found the most reliable information sources were friends, family or word of mouth (WOM) from someone they knew, followed by expert product reviews, and product reviews written by other consumers. The most unreliable information sources were advertising or infomercials, automated recommendations based on purchasing patterns or retailers. While a very small number of consumers evaluated products online, rating of products and online discussions were more frequent activities. The most popular social media websites for reviews were Facebook, Twitter, Amazon and e-Bay, indicating the importance of WOM in social networks and online media spaces that feature product reviews as it is the most persuasive piece of information in both online and offline social networks. These results suggest that ‘social customers’ must be considered as an integral part of a marketing strategy.
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Travel time in an important transport performance indicator. Different modes of transport (buses and cars) have different mechanical and operational characteristics, resulting in significantly different travel behaviours and complexities in multimodal travel time estimation on urban networks. This paper explores the relationship between bus and car travel time on urban networks by utilising the empirical Bluetooth and Bus Vehicle Identification data from Brisbane. The technologies and issues behind the two datasets are studied. After cleaning the data to remove outliers, the relationship between not-in-service bus and car travel time and the relationship between in-service bus and car travel time are discussed. The travel time estimation models reveal that the not-in-service bus travel time are similar to the car travel time and the in-service bus travel time could be used to estimate car travel time during off-peak hours
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The book documents new findings on the contribution of migrant young people to Australia’s urban life. The essays collected traces teenagers within a world of city suburbs and P plates, shopping malls and chat rooms and text messages. Proud of their migrant backgrounds, they are moving away from explicit ethnically defined cultural groups to focus on their place in contemporary Australian society. These young people through their every day activities are redefining what it means to be an Australian The book is edited by widely published cultural researchers Melissa Butcher from the University of Sydney and Mandy Thomas from the Australian National University who together worked on the GENERATE project. It is far too common for our youth to be portrayed as not belonging to our dominant or mainstream culture. In Ingenious, the editors study the kaleidoscope of influences and environments our youth move within - online networks, dance parties and more - to paint a flexible, innovative generation.