3,834 research outputs found
Ring-type singular solutions of the biharmonic nonlinear Schrodinger equation
We present new singular solutions of the biharmonic nonlinear Schrodinger
equation in dimension d and nonlinearity exponent 2\sigma+1. These solutions
collapse with the quasi self-similar ring profile, with ring width L(t) that
vanishes at singularity, and radius proportional to L^\alpha, where
\alpha=(4-\sigma)/(\sigma(d-1)). The blowup rate of these solutions is
1/(3+\alpha) for 4/d\le\sigma<4, and slightly faster than 1/4 for \sigma=4.
These solutions are analogous to the ring-type solutions of the nonlinear
Schrodinger equation.Comment: 21 pages, 13 figures, research articl
Reinforcement learning based local search for grouping problems: A case study on graph coloring
Grouping problems aim to partition a set of items into multiple mutually
disjoint subsets according to some specific criterion and constraints. Grouping
problems cover a large class of important combinatorial optimization problems
that are generally computationally difficult. In this paper, we propose a
general solution approach for grouping problems, i.e., reinforcement learning
based local search (RLS), which combines reinforcement learning techniques with
descent-based local search. The viability of the proposed approach is verified
on a well-known representative grouping problem (graph coloring) where a very
simple descent-based coloring algorithm is applied. Experimental studies on
popular DIMACS and COLOR02 benchmark graphs indicate that RLS achieves
competitive performances compared to a number of well-known coloring
algorithms
A Compensatory Liability Regime to Promote the Exchange of Microbial Genetic Resources for Research and Benefit Sharing
Female rhesus macaques were immunized with HIV virus-like particles (HIV-VLPs) or HIV DNA administered as sequential combinations of mucosal (intranasal) and systemic (intramuscular) routes, according to homologous or heterologous prime-boost schedules. The results show that in rhesus macaques only the sequential intranasal and intramuscular administration of HIV-VLPs, and not the intranasal alone, is able to elicit humoral immune response at the systemic as well as the vaginal level.funding agencies|Simian Vaccine Evaluation Unit (SVEU) of the Division of AIDS||European Community|201433|</p
Rottenberg and the Economics of Sport after 50 years: An Evaluation
Simon Rottenbergâs seminal 1956 article in the Journal of Political Economy, 1956, is generally accepted as the starting point for the development of the economics of sport. While he recognised that certain features of professional sports leagues were unusual he saw little reason to treat this industry any differently from a conventional industry. He discusses the importance of uncertainty of outcome, the monopsonistic nature of the labour market, the nature of the product and demand (attendances). He considers alternatives to the reserve clause, such as equal revenue sharing, maximum salary limits, equal market franchise distribution and roster limits. Each of these is rejected in favour of a free market solution which, on the basis of the invariance principle, he suggests will perform just as well as the reserve clause in allocating talent to where it is most productive. The ensuing literature has focused on all these issues, many of which have created considerable debate amongst sports economists. In particular the assumption of profit maximisation has been challenged and a divergence of views, reflected in the so-called North American and European models of sports leagues has emerged. Over the last 50 years sports leagues have expanded, TV markets have opened up and legal challenges to existing practices have multiplied. This paper seeks to evaluate Rottenbergâs contribution to a rapidly expanding field and to judge its relevance today.Sport, Monopsony, Monopoly Power
Robot Navigation in Unseen Spaces using an Abstract Map
Human navigation in built environments depends on symbolic spatial
information which has unrealised potential to enhance robot navigation
capabilities. Information sources such as labels, signs, maps, planners, spoken
directions, and navigational gestures communicate a wealth of spatial
information to the navigators of built environments; a wealth of information
that robots typically ignore. We present a robot navigation system that uses
the same symbolic spatial information employed by humans to purposefully
navigate in unseen built environments with a level of performance comparable to
humans. The navigation system uses a novel data structure called the abstract
map to imagine malleable spatial models for unseen spaces from spatial symbols.
Sensorimotor perceptions from a robot are then employed to provide purposeful
navigation to symbolic goal locations in the unseen environment. We show how a
dynamic system can be used to create malleable spatial models for the abstract
map, and provide an open source implementation to encourage future work in the
area of symbolic navigation. Symbolic navigation performance of humans and a
robot is evaluated in a real-world built environment. The paper concludes with
a qualitative analysis of human navigation strategies, providing further
insights into how the symbolic navigation capabilities of robots in unseen
built environments can be improved in the future.Comment: 15 pages, published in IEEE Transactions on Cognitive and
Developmental Systems (http://doi.org/10.1109/TCDS.2020.2993855), see
https://btalb.github.io/abstract_map/ for access to softwar
- âŠ