87,025 research outputs found
Connections between cosmic-ray physics, gamma-ray data analysis and Dark Matter detection
Cosmic-ray (CR) physics has been a prolific field of research for over a
century. The open problems related to CR acceleration, transport and modulation
are deeply connected with the indirect searches for particle dark matter (DM).
In particular, the high-quality gamma-ray data released by Fermi-LAT are under
the spotlight in the scientific community because of a recent claim about a
inner Galaxy anomaly: The necessity to disentangle the astrophysical emission
due to CR interactions from a possible DM signal is therefore compelling and
requires a deep knowledge of several non-trivial aspects regarding CR physics.
I review all these connections in this contribution. In the first part, I
present a detailed overview on recent results regarding modeling of cosmic-ray
(CR) production and propagation: I focus on the necessity to go beyond the
standard and simplified picture of uniform and homogeneous diffusion, showing
that gamma-ray data point towards different transport regimes in different
regions of the Galaxy; I sketch the impact of large-scale structure on CR
observables, and -- concerning the interaction with the Heliosphere -- I
mention the necessity to consider a charge-dependent modulation scenario. In
the second part, all these aspects are linked to the DM problem. I analyze the
claim of a inner Galaxy excess and discuss the impact of the non-trivial
aspects presented in the first part on our understanding of this anomaly.Comment: 16 pages, 8 figures. Proceeding of the ICRC 201
The politics of policy resistance: reconstructing higher education in Kosovo
This article considers attempts to incorporate lessons and transfer policies from Britain in the reconstruction of Higher Education in Kosovo after 1999. In doing so, it employs aspects of the lesson-drawing framework developed by Rose (1991 and 2001) and the related concepts of policy transfer and policy diffusion. Drawing on contributions from anthropology and democratization studies, we suggest development of the public policy frameworks for lesson drawing and policy transfer in circumstances characterised by asymmetric interdependence, in which the tactics and strategies of policy resistance by ‘subordinate’ recipient actors can be crucial. This article details the nature of policy resistance and sets out hypotheses for future research
Interests Diffusion in Social Networks
Understanding cultural phenomena on Social Networks (SNs) and exploiting the
implicit knowledge about their members is attracting the interest of different
research communities both from the academic and the business side. The
community of complexity science is devoting significant efforts to define laws,
models, and theories, which, based on acquired knowledge, are able to predict
future observations (e.g. success of a product). In the mean time, the semantic
web community aims at engineering a new generation of advanced services by
defining constructs, models and methods, adding a semantic layer to SNs. In
this context, a leapfrog is expected to come from a hybrid approach merging the
disciplines above. Along this line, this work focuses on the propagation of
individual interests in social networks. The proposed framework consists of the
following main components: a method to gather information about the members of
the social networks; methods to perform some semantic analysis of the Domain of
Interest; a procedure to infer members' interests; and an interests evolution
theory to predict how the interests propagate in the network. As a result, one
achieves an analytic tool to measure individual features, such as members'
susceptibilities and authorities. Although the approach applies to any type of
social network, here it is has been tested against the computer science
research community.
The DBLP (Digital Bibliography and Library Project) database has been elected
as test-case since it provides the most comprehensive list of scientific
production in this field.Comment: 30 pages 13 figs 4 table
What Have We Learned from Policy Transfer Research? Dolowitz and Marsh Revisited
Over the last decade, policy transfer has emerged as an important concept within public policy analysis, guiding both theoretical and empirical research spanning many venues and issue areas. Using Dolowitz and Marsh's 1996 stocktake as its starting point, this article reviews what has been learned by whom and for what purpose. It finds that the literature has evolved from its rather narrow, state-centred roots to cover many more actors and venues. While policy transfer still represents a niche topic for some researchers, an increasing number have successfully assimilated it into wider debates on topics such as globalisation, Europeanisation and policy innovation. This article assesses the concept's position in the overall ‘tool-kit’ of policy analysis, examines some possible future directions and reflects on their associated risks and opportunities
Together we stand, Together we fall, Together we win: Dynamic Team Formation in Massive Open Online Courses
Massive Open Online Courses (MOOCs) offer a new scalable paradigm for
e-learning by providing students with global exposure and opportunities for
connecting and interacting with millions of people all around the world. Very
often, students work as teams to effectively accomplish course related tasks.
However, due to lack of face to face interaction, it becomes difficult for MOOC
students to collaborate. Additionally, the instructor also faces challenges in
manually organizing students into teams because students flock to these MOOCs
in huge numbers. Thus, the proposed research is aimed at developing a robust
methodology for dynamic team formation in MOOCs, the theoretical framework for
which is grounded at the confluence of organizational team theory, social
network analysis and machine learning. A prerequisite for such an undertaking
is that we understand the fact that, each and every informal tie established
among students offers the opportunities to influence and be influenced.
Therefore, we aim to extract value from the inherent connectedness of students
in the MOOC. These connections carry with them radical implications for the way
students understand each other in the networked learning community. Our
approach will enable course instructors to automatically group students in
teams that have fairly balanced social connections with their peers, well
defined in terms of appropriately selected qualitative and quantitative network
metrics.Comment: In Proceedings of 5th IEEE International Conference on Application of
Digital Information & Web Technologies (ICADIWT), India, February 2014 (6
pages, 3 figures
Dynamic Monopolies in Colored Tori
The {\em information diffusion} has been modeled as the spread of an
information within a group through a process of social influence, where the
diffusion is driven by the so called {\em influential network}. Such a process,
which has been intensively studied under the name of {\em viral marketing}, has
the goal to select an initial good set of individuals that will promote a new
idea (or message) by spreading the "rumor" within the entire social network
through the word-of-mouth. Several studies used the {\em linear threshold
model} where the group is represented by a graph, nodes have two possible
states (active, non-active), and the threshold triggering the adoption
(activation) of a new idea to a node is given by the number of the active
neighbors.
The problem of detecting in a graph the presence of the minimal number of
nodes that will be able to activate the entire network is called {\em target
set selection} (TSS). In this paper we extend TSS by allowing nodes to have
more than two colors. The multicolored version of the TSS can be described as
follows: let be a torus where every node is assigned a color from a finite
set of colors. At each local time step, each node can recolor itself, depending
on the local configurations, with the color held by the majority of its
neighbors. We study the initial distributions of colors leading the system to a
monochromatic configuration of color , focusing on the minimum number of
initial -colored nodes. We conclude the paper by providing the time
complexity to achieve the monochromatic configuration
BOUNDARY ORGANIZATIONS: AN EFFICIENT STRUCTURE FOR MANAGING KNOWLEDGE IN DECISION-MAKING UNDER UNCERTAINTY
Modern environmental issues imply that decision-makers take into account opinions from experts of different spheres. Boundary organizations are institutions able to cross the gap between different areas of expertise and to act beyond the boundaries while remaining accountable to each side: by encouraging a flow of useful information, they permit an exchange to take place while maintaining the authority of each side, in order to provide a better knowledge and understanding of a situation characterized by uncertainty. Though never formally proved, this hypothesis is widely accepted based on the observation of existing boundary organizations. Through a multi-agent simulation, it is possible to assess their impact on the diffusion of opinions among experts. This virtual interaction of heterogeneous agents based on a model of continuous opinion dynamics over two dimensions, shows that boundary organizations have a significant quantitative impact on the diversity of opinions expressed and the number of experts agreeing to each emerging position.boundary organization, opinion, knowledge diffusion, multi-agent system, Agribusiness, Labor and Human Capital, Public Economics,
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