642 research outputs found
Multiple-Goal Heuristic Search
This paper presents a new framework for anytime heuristic search where the
task is to achieve as many goals as possible within the allocated resources. We
show the inadequacy of traditional distance-estimation heuristics for tasks of
this type and present alternative heuristics that are more appropriate for
multiple-goal search. In particular, we introduce the marginal-utility
heuristic, which estimates the cost and the benefit of exploring a subtree
below a search node. We developed two methods for online learning of the
marginal-utility heuristic. One is based on local similarity of the partial
marginal utility of sibling nodes, and the other generalizes marginal-utility
over the state feature space. We apply our adaptive and non-adaptive
multiple-goal search algorithms to several problems, including focused
crawling, and show their superiority over existing methods
Current relaxation in nonlinear random media
We study the current relaxation of a wave packet in a nonlinear random sample
coupled to the continuum and show that the survival probability decays as . For intermediate times , the exponent
satisfies a scaling law where is
the nonlinearity strength and is the localization length of the
corresponding random system with . For and we find a universal decay with which is a signature of the
{\it nonlinearity-induced delocalization}. Experimental evidence should be
observable in coupled nonlinear optical waveguides.Comment: revised version, PRL in press, 4 pages, 4 figs (fig 3 with reduced
quality
Reversing conditional orderings
We analyze some specific aspects concerning conditional orderings and relations among them. To this purpose we define a suitable concept of reversed conditional ordering and prove some related results. In particular we aim to compare the univariate stochastic orderings ≤ st, ≤ hr, and ≤ lr in terms of differences among different notions of conditional orderings. Some applications of our result to the analysis of positive dependence will be detailed. We concentrate attention to the case of a pair of scalar random variables X, Y . Suitable extensions to multivariate cases are possible
The signature of subsurface Kondo impurities in the local tunnel current
The conductance of a tunnel point-contact in an STM-like geometry having a
single defect placed below the surface is investigated theoretically. The
effect of multiple electron scattering by the defect after reflections by the
metal surface is taken into account. In the approximation of s-wave scattering
the dependence of the conductance on the applied voltage and the position of
the defect is obtained. The results are illustrated for a model s-wave phase
shift describing Kondo-resonance scattering. We demonstrate that multiple
electron scattering by the magnetic impurity plays a decisive role in the
point-contact conductance at voltages near the Kondo resonance. We find that
the sign and shape of the Kondo anomaly depends on the position of the defect.Comment: 13 pages, 4 figures. To be published in J. Phys.: Cond. Ma
Morphometric Parameters of Erythrocytes in Juvenile Mandarin Ducks Aix galerkulata
The morphometric parameters of erythrocytes in Mandarin ducks Aix galericulata have never been subjected to study even though this species is common in aviculture. The aim of this study is to investigate the morphometric parameters of erythrocytes in juvenile Mandarin ducks. A total of 1500 erythrocytes obtained from thirty Mandarin ducks were analysed. The smears of the peripheral blood were stained using Diff-Quik stain method, and the length and width of erythrocytes were measured using ImageJ program. The average length of the measured erythrocytes was 11.879 mu m. The maximal measured length of the erythrocytes was 10.O49 mu m, and the minimal measured length was 5.668 pm. The average width of the measured erythrocytes vvas 6.160 pm. The maximal measured width of the erythrocytes was 10.115 pm and the minimal measured width vvas 3.750 mu m. In conclusion, knowing morphometric parameters of Mandarin duck erythrocytes is the first step in evaluation process of erythrocytes functional state and health condition of an individual
Повышение помехозащищенности идентификации и распознавания гидролокационных сигналов от тел сложной формы на фоне реверберационных помех
Methods of identification and recognition of sonar signals reflected from the bodies with complex geometric shape have been developed and calibrated in hydroacoustic tank and at sea. Their greater noise immunity is achieved in comparison with well-known recognition methods. Comparison of these methods with wave front reversal method is given. Simulation results help to explain well-known fact that dolphins use multiple impulse sounding transmission with unequal interpulse periods.Разработаны и проверены в гидроакустическом бассейне и в морских условиях методы идентификации и распознавания гидролокационных сигналов, отраженных от тел сложной геометрической формы. Показана их бóльшая помехозащищенность по сравнению с известными методами распознавания. Приведено сравнение этих методов с методом обращения волнового фронта. Результаты моделирования позволяют объяснить известный факт применения дельфинами многоимпульсных зондирующих посылок с неравными расстояниями между импульсами
On the Bergman representative coordinates
We study the set where the so-called Bergman representative coordinates (or
Bergman functions) form an immersion. We provide an estimate of the size of a
maximal geodesic ball with respect to the Bergman metric, contained in this
set. By concrete examples we show that these estimates are the best possible.Comment: 20 page
Construction of free g-dimonoids
In this paper, the concept of a g-dimonoid is introduced and the construction of a free g-dimonoid is described. (A g-dimonoid is a duplex satisfying two additional identities.
Predatory Bacteria: A Potential Ally against Multidrug-Resistant Gram-Negative Pathogens
Multidrug-resistant (MDR) Gram-negative bacteria have emerged as a serious threat to human and animal health. Bdellovibrio spp. and Micavibrio spp. are Gram-negative bacteria that prey on other Gram-negative bacteria. In this study, the ability of Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus to prey on MDR Gram-negative clinical strains was examined. Although the potential use of predatory bacteria to attack MDR pathogens has been suggested, the data supporting these claims is lacking. By conducting predation experiments we have established that predatory bacteria have the capacity to attack clinical strains of a variety of ß-lactamase-producing, MDR Gram-negative bacteria. Our observations indicate that predatory bacteria maintained their ability to prey on MDR bacteria regardless of their antimicrobial resistance, hence, might be used as therapeutic agents where other antimicrobial drugs fail. © 2013 Kadouri et al
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