1,721,504 research outputs found
The quantum 1/2 BPS Wilson loop in N= 4 Chern-Simons-matter theories
Get PDFIn three dimensional N= 4 Chern-Simons-matter theories two independent fermionic Wilson loop operators can be defined, which preserve half of the supersymmetry charges and are cohomologically equivalent at classical level. We compute their three-loop expectation value in a convenient color sector and prove that the degeneracy is uplifted by quantum corrections. We expand the matrix model prediction in the same regime and by comparison we conclude that the quantum 1/2 BPS Wilson loop is the average of the two operators. We provide an all-loop argument to support this claim at any order. As a by-product, we identify the localization result at three loops as a correction to the framing factor induced by matter interactions. Finally, we comment on the quantum properties of the non-1/2 BPS Wilson loop operator defined as the difference of the two fermionic ones.Fil: Bianchi, Marco S.. Queen Mary, University Of London; Reino UnidoFil: Griguolo, Luca. Università di Parma; ItaliaFil: Leoni Olivera, Matías. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; ArgentinaFil: Mauri, Andrea. Universita Degli Studi Di Milano - Bicocca; ItaliaFil: Penati, Silvia. Universita Degli Studi Di Milano - Bicocca; Italia. Istituto Nazionale Di Fisica Nucleare, Frascati; ItaliaFil: Seminara, Domenico. Università degli Studi di Firenze; Itali
Methodologies for the development of crowd and social-based applications
No full textEven though search systems are very efficient in retrieving world-wide information, they cannot capture some peculiar aspects of user needs, such as subjective opinions, or information that require local or domain specific expertise. In these scenarios the knowledge of an expert or a friend’s advice can be more useful than any information retrieved by a search system. This way of exploiting human knowledge for information seeking and computational task is called Crowdsourcing. The main objective of this work is to develop methodologies for the creation of applications based on Crowdsourcing and social interaction. The outcome will be a framework based on model-driven approach that will allow end user to develop their own application with a fraction of the effort required by the traditional approaches. It will guarantee a strong control of the execution of the crowdsourcing task by mean of a declarative specification of objectives and quality measures. A prototype will be developed that will allow the creation and execution of task on various platforms. Validation of the approach will consist of quantitative and qualitative analysis of results and performance of the system upon some sample scenarios, where real users from social networks and crowdsourcing platforms will be involved
Model driven development of social media applications for environmental monitoring
Get PDFThe growth of social media and the resulting increase of user generated content attracted people coming from different fields interested in analyzing this kind of data. Recently user generated content has been used for environmental monitoring. In this paper, we propose a model-driven approach for developing social media applications for environmental monitoring that will provide a simplified solution for integrating various data sources, exploiting different platforms and allowing complex data analysis to be performed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Model-Driven Development of Social Network Enabled Applications with WebML and Social Primitives
No full textSocial technologies are transforming the Web to a place where users actively contribute to content production and opinion making. Social networking requirements are becoming a core part of the needs of modern enterprises too, which need ad-hoc Web platforms that incorporate the right set of social features for their business. This leads to the need to provide facilities and methods for developing such socially enabled applications. In this paper we propose a model-driven approach that is specifically focused on the development of Web applications that exploit social features. In particular, we describe an extension of the WebML notation (a Domain Specific Language designed to model Web applications), comprising a set of modeling concepts that encapsulate the logic of the interaction with the social platforms. Upon this, we define a set of design patterns that respond to the typical needs of enterprises and we show some sample application scenario
Adaptive and Interoperable Crowdsourcing
Get PDFCrowd-based computing is an increasingly popular paradigm for building Web applications, which uses the collective strength of human actors for performing tasks that are more suited to humans than computers. Interaction with the crowds was originally confined to specifically designed crowdsourcing platforms, such as Amazon Mechanical Turk. More recently, crowd-based computing has been reconsidered and extended, targeting social networks such as Facebook, Twitter, or LinkedIn, or including basic and direct interaction mechanisms, such as routing personal emails or tweets. Crowdsearcher, the system presented here, fosters interoperability and adaptation in crowd-based applications -- for example, the ability of supporting multiplatform applications and adapting them in reaction to events. This approach specifically supports dynamic interoperability (that is, the ability to modify the execution platforms while the application is ongoing) as a reaction to crowd behavior, which is hardly predictable. The authors show how to specify interoperability control at a high, declarative level and then implement it using active rules, thereby obtaining answers from crowds engaged in different communities. They also show the approach's effect on precision, delay, and cost
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Designing Complex Crowdsourcing Applications Covering Multiple Platforms and Tasks
No full textA number of emerging crowd-based applications cover very different scenarios, including opinion mining, multimedia data annotation, localised information gathering, marketing campaigns, expert response gathering, and so on. In most of these scenarios, applications can be decomposed into tasks that collectively produce their results; tasks interactions give rise to arbitrarily complex workflows.
In this paper we propose methods and tools for designing crowd-based workflows as interacting tasks. We describe the modelling concepts that are useful in this framework, including typical workflow patterns, whose function is to decompose a cognitively complex task into simple interacting tasks for cooperative solving.}{We then discuss how workflows and patterns are managed by CrowdSearcher, a system for designing, deploying and monitoring applications on top of crowd-based systems, including social networks and crowdsourcing platforms. Tasks performed by humans consist of simple operations which apply to homogeneous objects; the complexity of aggregating and interpreting task results is embodied within the framework. We show our approach at work on a validation scenario and we report quantitative findings, which highlight the effect of workflow design on the final results
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