493,102 research outputs found
Corruption and Resource Allocation: Evidence from China
Exploiting a unique data set containing transactions data from a panel of 769 Chinese state-owned enterprises between 1980 and 1989, this paper tests microeconomic implications of a pervasive form of corruption --official diversion of under-priced, in-plan goods to the market. Corruption has the predicted effects on resource allocation. Official under-pricing of in-plan goods, which lowers the marginal cost of diversion, increases the procurement of output into the plan for the purpose of diversion. Market competition introduced by allowing firms to sell directly to the market appears to reduce corruption and therefore lessen its distortions.http://deepblue.lib.umich.edu/bitstream/2027.42/39780/3/wp396.pd
PersonRank: Detecting Important People in Images
Always, some individuals in images are more important/attractive than others
in some events such as presentation, basketball game or speech. However, it is
challenging to find important people among all individuals in images directly
based on their spatial or appearance information due to the existence of
diverse variations of pose, action, appearance of persons and various changes
of occasions. We overcome this difficulty by constructing a multiple
Hyper-Interaction Graph to treat each individual in an image as a node and
inferring the most active node referring to interactions estimated by various
types of clews. We model pairwise interactions between persons as the edge
message communicated between nodes, resulting in a bidirectional
pairwise-interaction graph. To enrich the personperson interaction estimation,
we further introduce a unidirectional hyper-interaction graph that models the
consensus of interaction between a focal person and any person in a local
region around. Finally, we modify the PageRank algorithm to infer the
activeness of persons on the multiple Hybrid-Interaction Graph (HIG), the union
of the pairwise-interaction and hyperinteraction graphs, and we call our
algorithm the PersonRank. In order to provide publicable datasets for
evaluation, we have contributed a new dataset called Multi-scene Important
People Image Dataset and gathered a NCAA Basketball Image Dataset from sports
game sequences. We have demonstrated that the proposed PersonRank outperforms
related methods clearly and substantially.Comment: 8 pages, conferenc
Modular Properties of 3D Higher Spin Theory
In the three-dimensional sl(N) Chern-Simons higher-spin theory, we prove that
the conical surplus and the black hole solution are related by the
S-transformation of the modulus of the boundary torus. Then applying the
modular group on a given conical surplus solution, we generate a 'SL(2,Z)'
family of smooth constant solutions. We then show how these solutions are
mapped into one another by coordinate transformations that act non-trivially on
the homology of the boundary torus. After deriving a thermodynamics that
applies to all the solutions in the 'SL(2,Z)' family, we compute their
entropies and free energies, and determine how the latter transform under the
modular transformations. Summing over all the modular images of the conical
surplus, we write down a (tree-level) modular invariant partition function.Comment: 51 pages; v2: minor corrections and additions; v3: final version, to
appear in JHE
Collective flow from AA, pA to pp collisions - Toward a unified paradigm
I give an overview of the latest development in understanding collective
phenomena in high-multiplicity hadronic final state from relativistic
nucleus-nucleus, proton-nucleus and proton-proton collisions. Upon reviewing
the experimental data and confronting them with theoretical models, a unified
paradigm in describing the observed collectivity across all hadronic collision
systems is emerging. Potential future paths toward addressing key open
questions, especially on collectivity in small systems (pp, pA), are discussed.Comment: 9 pages, 6 figures, plenary contribution to Quark Matter 2017,
February 5-11 (2017), Chicago (IL), US
System size dependence of two-particle angular correlations in p+p, Cu+Cu and Au+Au collisions
We present a systematic study of two-particle angular correlations in p+p,
Cu+Cu and Au+Au collisions over a broad range of pseudorapidity and azimuthal
angle. The PHOBOS detector has a uniquely large angular coverage for inclusive
charged particles, which allows for the study of correlations on both long- and
short-range scales. A complex two-dimensional correlation structure emerges
which is interpreted in the context of a cluster model. The cluster size and
its decay width are extracted from the two-particle pseudorapidity correlation
function. The cluster size found in semi-central Cu+Cu and Au+Au collisions is
comparable to that found in p+p but a non-trivial increase of cluster size with
decreasing centrality is observed. Moreover, the comparison between Cu+Cu and
Au+Au systems shows an interesting scaling of the cluster size with the
measured fraction of total cross section (which is related to ),
suggesting a geometric origin. These results should provide insight into the
hadronization stage of the hot and dense medium created in heavy ion
collisions.Comment: 4 pages, 5 figures, presented at the 19th International Conference on
Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur,
India, February 4-10, 200
Observation of a "Ridge" correlation structure in high multiplicity proton-proton collisions: A brief review
This paper briefly reviews the striking experimental observation of a
ridge-like dihadron correlation structure in high multiplicity proton-proton
collisions at the Large Hadron Collider (LHC). Recent progress of both
experimental and theoretical efforts on understanding the physical origin of
the novel effect is reviewed. Outlook on future direction of possible new
studies is discussed.Comment: 16 pages, 12 figures, brief review for Modern Physics Letter
Current collection in an anisotropic plasma
A general method is given to derive the current-potential relations in anisotropic plasmas. Orbit limit current is assumed. The collector is a conductive sphere or an infinite cylinder. Any distribution which is an arbitrary function of the velocity vector can be considered as a superposition of many mono-energetic beams whose current-potential relations are known. The results for two typical pitch angle distributions are derived and discussed in detail. The general properties of the current potential relations are very similar to that of a Maxwellian plasma except for an effective temperature which varies with the angle between the magnetic field and the charging surface. The conclusions are meaningful to generalized geometries
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