On positive-influence target-domination
Consider a graph G = (V, E) and a vertex subset A ⊆ V. A vertex v is positive-influence dominated by A if either v is in A or at least half the number of neighbors of v belong to A. For a target vertex subset S ⊆ V, a vertex subset A is a positive-influence target-dominating set for target set S if every vertex in S is positive-influence dominated by A. Given a graph G and a target vertex subset S, the positive-influence target-dominating set (PITD) problem is to find the minimum positive-influence dominating set for target S. In this paper, we show two results: (1) The PITD problem has a polynomial-time (1+log[3/2*Delta])-approximation in general graphs where Delta is the maximum vertex-degree of the input graph. (2) For target set S with |S| = OMEGA(|V|), the PITD problem has a polynomial-time O(1)-approximation in power-law graphs.
By analyzing the logs of corporate e-mail networks we found a number of patterns, showing how the size of ego-networks of individual employees changes on a day by day basis. We proposed a simple model that adequately describes the observed time dependence of an employee's "social circle". Comparison of experimental data with the theoretical model showed that employees are divided into two groups - with fast and slow changes in their social circles, respectively. We believe that the presence of these groups reflects both project-type and process-type of employees' activities. Comparison of data obtained before and during the global economic crisis has shown that the crisis led to an actual reduction in project-type activities.
Legal pluralism and the experience of the state in the Caucasus are at the centre of this edited volume. This is a region affected by a multitude of legal orders and the book describes social action and governance in the light of this, and considers how conceptions of order are enforced, used, followed and staged in social networks and legal practice. Principally, how is the state perceived and how does it perform in both the North and South Caucasus? From elections in Dagestan and Armenia to uses of traditional law in Ingushetia and Georgia, from repression of journalism in Azerbaijan to the narrations of anti-corruption campaigns in Georgia - the text reflects the multifarious uses and performances of law and order. The collection includes approaches from different scholarly traditions and their respective theoretical background and therefore forms a unique product of multinational encounters.
This book presents recent research developments in social networks, economics, management, marketing and optimization applied to sports. The volume will be of interest to students, researchers, managers from sports, policy makers and as well athletes. In particular the book contains research papers and reviews addressing the following issues: social network tools for player selection, movement and pricing in team sports, methods for ranking teams and evaluating players' performance, economics and marketing issues related to sports clubs, techniques for predicting outcomes of sports competitions, optimal strategies in sports, scheduling and managing sports tournaments, optimal referee assignment techniques and the economics and marketing of sports entertainment.
This book presents a course of English for Specific Purposes devoted specifically to the widely-discussed topic Web 2.0. It covers several aspects of online communication ranging from online friendship to business interacions. The activities presented in the coursebook are aimed at developing students’ communicative competence in both written and oral discourse. Web 2.0 includes a variety of authentic articles that arouse interest and provoke discussions. It also presents listening texts based on professional podcasts. Most grammar and vocabulary activities are developed from authentic texts as well.
Web 2.0 can be used at the B2-C1 levels of Common European Famework. The coursebook will help learn and practice the target vocabulary. It will be relevant to those interested in the development of Information and Communication Technologies in general and the Internet in particular.
This proceedings publication is a compilation of selected contributions from the “Third International Conference on the Dynamics of Information Systems” which took place at the University of Florida, Gainesville, February 16–18, 2011. The purpose of this conference was to bring together scientists and engineers from industry, government, and academia in order to exchange new discoveries and results in a broad range of topics relevant to the theory and practice of dynamics of information systems. Dynamics of Information Systems: Mathematical Foundation presents state-of-the art research and is intended for graduate students and researchers interested in some of the most recent discoveries in information theory and dynamical systems. Scientists in other disciplines may also benefit from the applications of new developments to their own area of study.
The article discusses the phenomenon of interconnected glocal hospitality communities which have recently spread over the world in the context of the internet development and cultural globalization processes. It focuses on a typical community of users of CouchSurfi ng.org, a major social hospitality network in St. Petersburg. The author argues that, in the framework of this web service, there occurs a transformation of virtual groups of users localized in various spots of the globe into actual interconnected glocal communities which shape shared identities, norms, values, and practices among its members.
The following article is devoted to analysis of civil identity's social foundations through the actor-network theory framework. Three aspects are considered: the specific character of civic identity as a subject-object interaction between the actor and the state, the network interactions in the «real» and «virtual» spaces, social memory, social and cultural experience, socially-relevant knowledge as a basis for forming a shared social context of civic identity.
There have been implemented engineering and development of multi-agent recommender system «EZSurf» that performs analysis of interests and provides recommendations for the social network «VKontakte» users based on the data from profile of particular user. During the work process different methods and technological solutions have been analyzed with examination of their advantages and disadvantages. Besides of that the comparative analysis of analogous products has been held where the most similar is Russian start-up service - Surfingbird. Based on this analysis the decision of recommender system implementation and integration has been accepted. The feature of this system is that it uses social network “VKontakte” profile for user’s data collection and API of third-party services (LastFM, TheMovieDB) for an extraction of information about similar objects. Such an approach contributes into optimization of recommender system, because it does not require creation of its own object classification system and objects database. The functionality of multi-agent system was separated between three agents. First agent (Collector) collects user data from “VKontakte” profile using VK API. Second agent (Analyzer) collects similar objects from databases of thitd-party services (LastFM, TheMovieDB) that will be the criteria for further search of recommendatory content. For search and selection of information an agent (Recommender) that works as web-crawler has been implemented. System «EZSurf» can be exploited by the users of social network “VKontakte” in everyday life for time economy on web-surfing process. At the same time they will get recommendations on content that are filtered depending on preferences of every particular user.
A form for an unbiased estimate of the coefficient of determination of a linear regression model is obtained. It is calculated by using a sample from a multivariate normal distribution. This estimate is proposed as an alternative criterion for a choice of regression factors.