20,483 research outputs found
A Generalized Approach to Complex Networks
This work describes how the formalization of complex network concepts in
terms of discrete mathematics, especially mathematical morphology, allows a
series of generalizations and important results ranging from new measurements
of the network topology to new network growth models. First, the concepts of
node degree and clustering coefficient are extended in order to characterize
not only specific nodes, but any generic subnetwork. Second, the consideration
of distance transform and rings are used to further extend those concepts in
order to obtain a signature, instead of a single scalar measurement, ranging
from the single node to whole graph scales. The enhanced discriminative
potential of such extended measurements is illustrated with respect to the
identification of correspondence between nodes in two complex networks, namely
a protein-protein interaction network and a perturbed version of it. The use of
other measurements derived from mathematical morphology are also suggested as a
means to characterize complex networks connectivity in a more comprehensive
fashion.Comment: 10 pages, 2 figur
Fractional statistical dynamics and fractional kinetics
We apply the subordination principle to construct kinetic fractional
statistical dynamics in the continuum in terms of solutions to Vlasov-type
hierarchies. As a by-product we obtain the evolution of the density of
particles in the fractional kinetics in terms of a non-linear Vlasov-type
kinetic equation. As an application we study the intermittency of the
fractional mesoscopic dynamics.Comment: Published in Methods of Functional Analysis and Topology (MFAT),
available at http://mfat.imath.kiev.ua/article/?id=890. arXiv admin note:
text overlap with arXiv:1604.0380
Adverse Selection and Risk Aversion in Capital Markets
We generalize the Boadway and Keen (2006) model of adverse selection in a capital market to allow for risk aversion on the part of entrepreneurs. We show that the Boadway and Keen conclusion-that adverse selection leads to excessive investment-does not necessarily hold when entrepreneurs are risk averse. We use their framework, with the additional assumption of risk aversion, to analyze the effect of policies that would reduce entrepreneurs' reliance on debt or equity financing by outside investors. We show that such policies, by exposing entrepreneurs to more down-side risk, may reduce the level of investment in risky projects, increase inequality and potentially reduce social welfare.adverse selection; capital markets; inefficiency; risk and entrepreneurship
Towards runtime discovery, selection and composition of semantic services
Service-orientation is gaining momentum in distributed software applications, mainly because it facilitates interoperability and allows application designers to abstract from underlying implementation technologies. Service composition has been acknowledged as a promising approach to create composite services that are capable of supporting service user needs, possibly by personalising the service delivery through the use of context information or user preferences. In this paper we discuss the challenges of automatic service composition, and present DynamiCoS, which is a novel framework that aims at supporting service composition on demand and at runtime for the benefit of service end-users. We define the DynamiCoS framework based on a service composition life-cycle. Framework mechanisms are introduced to tackle each of the phases and requirements of this life-cycle. Semantic services are used in our framework to enable reasoning on the service requests issued by end users, making it possible to automate service discovery, selection and composition. We validate our framework with a prototype that we have built in order to experiment with the mechanisms we have designed. The prototype was evaluated in a testing environment using some use case scenarios. The results of our evaluation give evidences of the feasibility of our approach to support runtime service composition. We also show the benefits of semantic-based frameworks for service composition, particularly for end-users who will be able to have more control on the service composition process
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