10,667 research outputs found
On the Price of Anarchy of Highly Congested Nonatomic Network Games
We consider nonatomic network games with one source and one destination. We
examine the asymptotic behavior of the price of anarchy as the inflow
increases. In accordance with some empirical observations, we show that, under
suitable conditions, the price of anarchy is asymptotic to one. We show with
some counterexamples that this is not always the case. The counterexamples
occur in very simple parallel graphs.Comment: 26 pages, 6 figure
Ladders for Wilson Loops Beyond Leading Order
We set up a general scheme to resum ladder diagrams for the quark-anti-quark
potential in N=4 super-Yang-Mills theory, and do explicit calculations at the
next-to-leading order. The results perfectly agree with string theory in
AdS(5)xS(5) when continued to strong coupling, in spite of a potential
order-of-limits problem.Comment: 18 pages, 5 figure
Spectral singularities in PT-symmetric periodic finite-gap systems
The origin of spectral singularities in finite-gap singly periodic
PT-symmetric quantum systems is investigated. We show that they emerge from a
limit of band-edge states in a doubly periodic finite gap system when the
imaginary period tends to infinity. In this limit, the energy gaps are
contracted and disappear, every pair of band states of the same periodicity at
the edges of a gap coalesces and transforms into a singlet state in the
continuum. As a result, these spectral singularities turn out to be analogous
to those in the non-periodic systems, where they appear as zero-width
resonances. Under the change of topology from a non-compact into a compact one,
spectral singularities in the class of periodic systems we study are
transformed into exceptional points. The specific degeneration related to the
presence of finite number of spectral singularities and exceptional points is
shown to be coherently reflected by a hidden, bosonized nonlinear
supersymmetry.Comment: 16 pages, 3 figures; a difference between spectral singularities and
exceptional points specified, the version to appear in PR
Customers’ experiences of fast food delivery services: uncovering the semantic core benefits, actual and augmented product by text mining
Purpose
This study conceptualizes food delivery services as service mix decisions (SMDs) and illustrates a data-driven approach for the analysis of customers' written experiences.
Design/methodology/approach
Web scraping, text mining techniques as well as multivariate statistics are combined to uncover the structure of the three tiers of SMD from consumers' point of view.
Findings
The analyses reveal that fast food delivery is not primarily about speed but that there are four distinct experiential factors to be considered for SMDs. Fast food delivery services are associated both with the actual product (i.e. product issues and brand satisfaction) and with the augmented product (payment process and service handling).
Originality/value
Findings demonstrate the relevance of SMDs in omnichannel food retail environments and guide researchers in multistage analyses of consumers' online food reviews
Bottleneck Routing Games with Low Price of Anarchy
We study {\em bottleneck routing games} where the social cost is determined
by the worst congestion on any edge in the network. In the literature,
bottleneck games assume player utility costs determined by the worst congested
edge in their paths. However, the Nash equilibria of such games are inefficient
since the price of anarchy can be very high and proportional to the size of the
network. In order to obtain smaller price of anarchy we introduce {\em
exponential bottleneck games} where the utility costs of the players are
exponential functions of their congestions. We find that exponential bottleneck
games are very efficient and give a poly-log bound on the price of anarchy:
, where is the largest path length in the
players' strategy sets and is the set of edges in the graph. By adjusting
the exponential utility costs with a logarithm we obtain games whose player
costs are almost identical to those in regular bottleneck games, and at the
same time have the good price of anarchy of exponential games.Comment: 12 page
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