13,408 research outputs found
Experimental Signatures of Anomaly Induced DCC Formation
We discuss characteristic experimental signatures related to the formation of
domains of disoriented chiral condensate (DCC) triggered by the axial anomaly
in relativistic heavy ion collisions. We predict that the enhancement of the
fraction of neutral pions compared to all pions depends on the angle of
emission with respect to the scattering plane and is concentrated at small
transverse momentum and small rapidity in the center-of-mass frame. The
anisotropy with respect to the reaction plane is also observable in the
inclusive photon distribution.Comment: 11 pages, 4 figures, REVTEX, discussion on photon distribution added,
one figure adde
Electron Impact Excitation Cross Sections for Hydrogen-Like Ions
We present cross sections for electron-impact-induced transitions n --> n' in
hydrogen-like ions C 5+, Ne 9+, Al 12+, and Ar 17+. The cross sections are
computed by Coulomb-Born with exchange and normalization (CBE) method for all
transitions with n < n' < 7 and by convergent close-coupling (CCC) method for
transitions with n 2s and 1s
--> 2p are presented as well. The CCC and CBE cross sections agree to better
than 10% with each other and with earlier close-coupling results (available for
transition 1 --> 2 only). Analytical expression for n --> n' cross sections and
semiempirical formulae are discussed.Comment: RevTeX, 5 pages, 13 PostScript figures, submitted to Phys. Rev.
The divider set of explicit parametric geometry
In this paper we describe a novel concept for classification
of complex parametric geometry based on the concept
of the Divider Set. The Divider Set is an alternative concept
to maximal disks, Voronoi sets and cut loci. The Divider
Set is based on a formal definition relating to topology
and differential geometry. In this paper firstly we discuss
the formal definition of the Divider Set for complex
3-dimensional geometry. This is then followed by the introduction
of a computationally feasible algorithm for computing
the Divider Set for geometry which can be defined
in explicit parametric form. Thus, an explicit solution form
taking advantage of the special form of the parametric geometry
is presented. We also show how the Divider Set can
be computed for various complex parametric geometry by
means of illustrating our concept through a number of example
Conformative Filtering for Implicit Feedback Data
Implicit feedback is the simplest form of user feedback that can be used for
item recommendation. It is easy to collect and is domain independent. However,
there is a lack of negative examples. Previous work tackles this problem by
assuming that users are not interested or not as much interested in the
unconsumed items. Those assumptions are often severely violated since
non-consumption can be due to factors like unawareness or lack of resources.
Therefore, non-consumption by a user does not always mean disinterest or
irrelevance. In this paper, we propose a novel method called Conformative
Filtering (CoF) to address the issue. The motivating observation is that if
there is a large group of users who share the same taste and none of them have
consumed an item before, then it is likely that the item is not of interest to
the group. We perform multidimensional clustering on implicit feedback data
using hierarchical latent tree analysis (HLTA) to identify user `tastes' groups
and make recommendations for a user based on her memberships in the groups and
on the past behavior of the groups. Experiments on two real-world datasets from
different domains show that CoF has superior performance compared to several
common baselines
Scaling properties at freeze-out in relativistic heavy-ion collisions
Identified charged pion, kaon, and proton spectra are used to explore the system size dependence of bulk freeze-out properties in Cu+Cu collisions at √sNN=200 and 62.4 GeV. The data are studied with hydrodynamically motivated blast-wave and statistical model frameworks in order to characterize the freeze-out properties of the system. The dependence of freeze-out parameters on beam energy and collision centrality is discussed. Using the existing results from Au + Au and pp collisions, the dependence of freeze-out parameters on the system size is also explored. This multidimensional systematic study furthers our understanding of the QCD phase diagram revealing the importance of the initial geometrical overlap of the colliding ions. The analysis of Cu+Cu collisions expands the system size dependence studies from Au+Au data with detailed measurements in the smaller system. The systematic trends of the bulk freeze-out properties of charged particles is studied with respect to the total charged particle multiplicity at midrapidity, exploring the influence of initial state effects
A review on data stream classification
At this present time, the significance of data streams cannot be denied as many researchers have placed their focus on the research areas of databases, statistics, and computer science. In fact, data streams refer to some data points sequences that are found in order with the potential to be non-binding, which is generated from the process of generating information in a manner that is not stationary. As such the typical tasks of searching data have been linked to streams of data that are inclusive of clustering, classification, and repeated mining of pattern. This paper presents several data stream clustering approaches, which are based on density, besides attempting to comprehend the function of the related algorithms; both semi-supervised and active learning, along with reviews of a number of recent studies
Maximizing Maximal Angles for Plane Straight-Line Graphs
Let be a plane straight-line graph on a finite point set
in general position. The incident angles of a vertex
of are the angles between any two edges of that appear consecutively in
the circular order of the edges incident to .
A plane straight-line graph is called -open if each vertex has an
incident angle of size at least . In this paper we study the following
type of question: What is the maximum angle such that for any finite set
of points in general position we can find a graph from a certain
class of graphs on that is -open? In particular, we consider the
classes of triangulations, spanning trees, and paths on and give tight
bounds in most cases.Comment: 15 pages, 14 figures. Apart of minor corrections, some proofs that
were omitted in the previous version are now include
Comparative Evaluation of Action Recognition Methods via Riemannian Manifolds, Fisher Vectors and GMMs: Ideal and Challenging Conditions
We present a comparative evaluation of various techniques for action
recognition while keeping as many variables as possible controlled. We employ
two categories of Riemannian manifolds: symmetric positive definite matrices
and linear subspaces. For both categories we use their corresponding nearest
neighbour classifiers, kernels, and recent kernelised sparse representations.
We compare against traditional action recognition techniques based on Gaussian
mixture models and Fisher vectors (FVs). We evaluate these action recognition
techniques under ideal conditions, as well as their sensitivity in more
challenging conditions (variations in scale and translation). Despite recent
advancements for handling manifolds, manifold based techniques obtain the
lowest performance and their kernel representations are more unstable in the
presence of challenging conditions. The FV approach obtains the highest
accuracy under ideal conditions. Moreover, FV best deals with moderate scale
and translation changes
Mapping the Monetization Challenge of Gaming in Various Domains
The cost of developing successful games for either entertainment or business purposes is a high-risk investment but mandatory due to the nature of the sector. However, there are discrete and innovative ways that minimize the investments risk and assure profitability without losing the player’s engagement. Gaming monetization can be approached from direct or indirect financial charges based on the scope of the game and its target group. As of today, no monetization practice can be considered as a silver bullet as they are all affected by geographical, cultural, social, economic and other factors. This paper attempts to define the major monetization elements in the gaming industry. It also attempts to define the major gaming categories and subcategories and associate on them the monetization elements and techniques. Furthermore, it creates a map for the development of gamification monetization approaches per case which can contribute towards effective gaming investments management
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