pinecone/core-2020-05-10-deduplication huggingface dataset:
Text retrieval methods for item ranking in collaborative filtering

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-20161-5_30Proceedings of 33rd European Conference on IR Research, ECIR 2011, Dublin, Ireland, April 18-21, 2011.Collaborative Filtering (CF) aims at predicting unknown ratings of a user from other similar users. The uniqueness of the problem has made its formulation distinctive to other information retrieval problems. While the formulation has proved to be effective in rating prediction tasks, it has limited the potential connections between these algorithms and Information Retrieval (IR) models. In this paper we propose a common notational framework for IR and rating-based CF, as well as a technique to provide CF data with a particular structure, in order to be able to use any IR weighting function with it. We argue that the flexibility of our approach may yield to much better performing algorithms. In fact, in this work we have found that IR models perform well in item ranking tasks, along with different normalization strategies.This work was supported by the Spanish Ministry of Science
and Innovation (TIN2008-06566-C04-02), and the Regional Government of
Madrid (S2009TIC-1542
What makes re-finding information difficult? A study of email re-finding

Re-nding information that has been seen or accessed before is a task which can be relatively straight-forward, but often it can be extremely challenging, time-consuming and frustrating. Little is known, however, about what makes one re-finding task harder or easier than another. We performed a user study to learn about the contextual factors that influence users' perception of task diculty in the context of re-finding email messages. 21 participants were issued re-nding tasks to perform on their own personal collections. The participants' responses to questions about the tasks combined with demographic data and collection statistics for the experimental population provide a rich basis to investigate the variables that can influence the perception of diculty. A logistic regression model was developed to examine the relationships be- tween variables and determine whether any factors were associated with perceived task diculty. The model reveals strong relationships between diculty and the time lapsed since a message was read, remembering when the sought-after email was sent, remembering other recipients of the email, the experience of the user and the user's ling strategy. We discuss what these findings mean for the design of re-nding interfaces and future re-finding research
Back to the roots : mean-variance analysis of relevance estimations

Recently, mean-variance analysis has been proposed as a novel paradigm to model document ranking in Information Retrieval. The main merit of this approach is that it diversifies the ranking of retrieved documents. In its original formulation, the strategy considers both the mean of relevance estimates of retrieved documents and their variance. How- ever, when this strategy has been empirically instantiated, the concepts of mean and variance are discarded in favour of a point-wise estimation of relevance (to replace the mean) and of a parameter to be tuned or, alternatively, a quantity dependent upon the document length (to replace the variance). In this paper we revisit this ranking strategy by going back to its roots: mean and variance. For each retrieved document, we infer a relevance distribution from a series of point-wise relevance estimations provided by a number of different systems. This is used to compute the mean and the variance of document relevance estimates. On the TREC Clueweb collection, we show that this approach improves the retrieval performances. This development could lead to new strategies to address the fusion of relevance estimates provided by different systems
Modelling Oscillator synchronisation during vertebrate axis segmentation

he somitogenesis clock regulates the periodicity with which somites form in the posterior pre-somitic mesoderm. Whilst cell heterogeneity results in noisy oscillation rates amongst constituent cells, synchrony within the population is maintained as oscillators are entrained via juxtracine signalling mechanisms. Here we consider a population of phase-coupled oscillators and investigate how biologically motivated perturbations to the entrained state can perturb synchrony within the population. We find that the ratio of mitosis length to clock period can influence levels of desynchronisation. Moreover, we observe that random cell movement, and hence change of local neighbourhoods, increases synchronisation
Strategies for reducing and correcting OCR errors

In this paper we describe our efforts in reducing and correcting OCR errors in the context of building a large multilingual heritage corpus of Alpine texts which is based on digitizing the publications of various Alpine clubs. We have already digitized the yearbooks of the Swiss Alpine Club from its start in 1864 until 1995 with more than 75,000 pages resulting in 29 million running words. Since these books have come out continuously, they represent a unique basis for historical, cultural and linguistic research. We used commercial OCR systems for the conversion from the scanned images to searchable text. This poses several challenges. For example, the built-in lexicons of the OCR systems do not cover the 19th century German spelling, the Swiss German spelling variants and the plethora of toponyms that are characteristic of our text genre. We also realized that different OCR systems make different recognition errors. We therefore run two OCR systems over all our scanned pages and merge the output. Merging is especially tricky at spots where both systems result in partially correct word groups. We describe our strategies for reducing OCR errors by enlarging the systems’ lexicons and by two post-correction methods namely, merging the output of two OCR systems and auto- correction based on additional lexical resources
Tidal stirring of Milky Way satellites: a simple picture with the integrated tidal force

Most of dwarf spheroidal galaxies in the Local Group were probably formed via environmental processes like the tidal interaction with the Milky Way. We study this process via N-body simulations of dwarf galaxies evolving on seven different orbits around the Galaxy. The dwarf galaxy is initially composed of a rotating stellar disk and a dark matter halo. Due to the action of tidal forces it loses mass and the disk gradually transforms into a spheroid while stellar motions become increasingly random. We measure the characteristic scale-length of the dwarf, its maximum circular velocity, mass, shape and kinematics as a function of the integrated tidal force along the orbit. The final properties of the evolved dwarfs are remarkably similar if the total tidal force they experienced was the same, independently of the actual size and eccentricity of the orbit
And the winner is: galaxy mass

The environment is known to affect the formation and evolution of galaxies
considerably best visible through the well-known morphology-density
relationship. We study the effect of environment on the evolution of early-type
galaxies for a sample of 3,360 galaxies morphologically selected by visual
inspection from the SDSS in the redshift range 0.05<z<0.06, and analyse
luminosity-weighted age, metallicity, and alpha/Fe ratio as function of
environment and galaxy mass. We find that on average 10 per cent of early-type
galaxies are rejuvenated through minor recent star formation. This fraction
increases with both decreasing galaxy mass and decreasing environmental
density. However, the bulk of the population obeys a well-defined scaling of
age, metallicity, and alpha/Fe ratio with galaxy mass that is independent of
environment. Our results contribute to the growing evidence in the recent
literature that galaxy mass is the major driver of galaxy formation. Even the
morphology-density relationship may actually be mass-driven, as the consequence
of an environment dependent characteristic galaxy mass coupled with the fact
that late-type galaxy morphologies are more prevalent in low-mass galaxies.Comment: 5 pages, proceedings of JENAM 2010, Symposium 2: "Environment and the
  formation of galaxies: 30 years later
The effect of the environment on the gas kinematics and morphologies of
  distant galaxies

With the aim of understanding which physical processes are primarily
responsible for the transformation of spiral galaxies into S0s in clusters, we
study the gas kinematics, morphological disturbances, and the Tully-Fisher
relation (TFR) of distant galaxies in various environments. We use the ESO
Distant Cluster Survey (EDisCS) dataset, that spans a broad range of cluster
and galaxy properties at 0.3 < z < 0.8. Our results indicate that the physical
mechanism acting on cluster galaxies (with M_B < -20 mag) must be strong enough
to significantly disturb the gas in cluster galaxies, but at the same time,
mild enough to leave the stellar structure unaffected.Comment: Proceedings from JENAM 2010, Symposium 2 (Environment and the
  Formation of Galaxies
The Void Galaxy Survey

The Void Galaxy Survey (VGS) is a multi-wavelength program to study $\sim$60
void galaxies. Each has been selected from the deepest interior regions of
identified voids in the SDSS redshift survey on the basis of a unique geometric
technique, with no a prior selection of intrinsic properties of the void
galaxies. The project intends to study in detail the gas content, star
formation history and stellar content, as well as kinematics and dynamics of
void galaxies and their companions in a broad sample of void environments. It
involves the HI imaging of the gas distribution in each of the VGS galaxies.
Amongst its most tantalizing findings is the possible evidence for cold gas
accretion in some of the most interesting objects, amongst which are a polar
ring galaxy and a filamentary configuration of void galaxies. Here we shortly
describe the scope of the VGS and the results of the full analysis of the pilot
sample of 15 void galaxies.Comment: 9 pages, 6 figures. This is an extended version of a paper to appear
  in "Environment and the Formation of Galaxies: 30 years later", Proceedings
  of Symposium 2 of JENAM 2010, eds. I. Ferreras, A. Pasquali, ASSP, Springer.
  Version with highres figures at
  http://www.astro.rug.nl/~weygaert/vgs_jenam_weygaert.col.pd
From fields to a super-cluster: the role of the environment at z=0.84
  with HiZELS

At z=0, clusters are primarily populated by red, elliptical and massive
galaxies, while blue, spiral and lower-mass galaxies are common in low-density
environments. Understanding how and when these differences were established is
of absolute importance for our understanding of galaxy formation and evolution,
but results at high-z remain contradictory. By taking advantage of the widest
and deepest H-alpha narrow-band survey at z=0.84 over the COSMOS and UKIDSS UDS
fields, probing a wide range of densities (from poor fields to rich groups and
clusters, including a confirmed super-cluster with a striking filamentary
structure), we show that the fraction of star-forming galaxies falls
continuously from ~40% in fields to approaching 0% in rich groups/clusters. We
also find that the median SFR increases with environmental density, at least up
to group densities - but only for low and medium mass galaxies, and thus such
enhancement is mass-dependent at z~1. The environment also plays a role in
setting the faint-end slope (alpha) of the H-alpha luminosity function. Our
findings provide a sharper view on galaxy formation and evolution and reconcile
previously contradictory results at z~1: stellar mass is the primary predictor
of star formation activity, but the environment also plays a major role.Comment: 5 pages, 4 figures, to appear in the proceedings of JENAM 2010 S2:
  `Environment and the Formation of Galaxies: 30 years later', ASSP, Springe
Reconciling a significant hierarchical assembly of massive early-type
  galaxies at z<~1 with mass downsizing

Hierarchical models predict that massive early-type galaxies (mETGs) are the
latest systems to be in place into the cosmic scenario (at z<~0.5), conflicting
with the observational phenomenon of galaxy mass downsizing, which poses that
the most massive galaxies have been in place earlier that their lower-mass
counterparts (since z~0.7). We have developed a semi-analytical model to test
the feasibility of the major-merger origin hypothesis for mETGs, just
accounting for the effects on galaxy evolution of the major mergers strictly
reported by observations. The most striking model prediction is that very few
present-day mETGs have been really in place since z~1, because ~90% of the
mETGs existing at z~1 are going to be involved in a major merger between z~1
and the present. Accounting for this, the model derives an assembly redshift
for mETGs in good agreement with hierarchical expectations, reproducing
observational mass downsizing trends at the same time.Comment: 2 pages, 1 figure, Proceedings of Symposium 2 of JENAM 2010,
  "Environment and the Formation of Galaxies: 30 years later", ed. I. Ferreras
  and A. Pasquali, Astrophysics & Space Science Proceedings, Springe
Tidal stirring of Milky Way satellites: a simple picture with the
  integrated tidal force

Most of dwarf spheroidal galaxies in the Local Group were probably formed via
environmental processes like the tidal interaction with the Milky Way. We study
this process via N-body simulations of dwarf galaxies evolving on seven
different orbits around the Galaxy. The dwarf galaxy is initially composed of a
rotating stellar disk and a dark matter halo. Due to the action of tidal forces
it loses mass and the disk gradually transforms into a spheroid while stellar
motions become increasingly random. We measure the characteristic scale-length
of the dwarf, its maximum circular velocity, mass, shape and kinematics as a
function of the integrated tidal force along the orbit. The final properties of
the evolved dwarfs are remarkably similar if the total tidal force they
experienced was the same, independently of the actual size and eccentricity of
the orbit.Comment: 5 pages, 2 figures, contribution to the proceedings of JENAM 2010 in
  Lisbon, Symposium 2 "Environment and the formation of galaxies: 30 years
  later", comments welcom
Numerical methods for computing Casimir interactions

We review several different approaches for computing Casimir forces and
related fluctuation-induced interactions between bodies of arbitrary shapes and
materials. The relationships between this problem and well known computational
techniques from classical electromagnetism are emphasized. We also review the
basic principles of standard computational methods, categorizing them according
to three criteria---choice of problem, basis, and solution technique---that can
be used to classify proposals for the Casimir problem as well. In this way,
mature classical methods can be exploited to model Casimir physics, with a few
important modifications.Comment: 46 pages, 142 references, 5 figures. To appear in upcoming Lecture
  Notes in Physics book on Casimir Physic
Fluctuation-induced forces between atoms and surfaces: the
  Casimir-Polder interaction

Electromagnetic fluctuation-induced forces between atoms and surfaces are
generally known as Casimir-Polder interactions. The exact knowledge of these
forces is rapidly becoming important in modern experimental set-ups and for
technological applications. Recent theoretical and experimental investigations
have shown that such an interaction is tunable in strength and sign, opening
new perspectives to investigate aspects of quantum field theory and
condensed-matter physics. In this Chapter we review the theory of
fluctuation-induced interactions between atoms and a surface, paying particular
attention to the physical characterization of the system. We also survey some
recent developments concerning the role of temperature, situations out of
thermal equilibrium, and measurements involving ultra-cold atoms.Comment: 44 pages, 14 figure. Invited review paper to appear in Lecture Notes
  in Physics for a volume on "Casimir physics" edited by D. Dalvit, P. Milonni,
  D. Roberts, and F. da Rosa. Publisher Springer-Verlag (2010
Fluctuations, dissipation and the dynamical Casimir effect

Vacuum fluctuations provide a fundamental source of dissipation for systems
coupled to quantum fields by radiation pressure. In the dynamical Casimir
effect, accelerating neutral bodies in free space give rise to the emission of
real photons while experiencing a damping force which plays the role of a
radiation reaction force. Analog models where non-stationary conditions for the
electromagnetic field simulate the presence of moving plates are currently
under experimental investigation. A dissipative force might also appear in the
case of uniform relative motion between two bodies, thus leading to a new kind
of friction mechanism without mechanical contact. In this paper, we review
recent advances on the dynamical Casimir and non-contact friction effects,
highlighting their common physical origin.Comment: 39 pages, 4 figures. Review paper to appear in Lecture Notes in
  Physics, Volume on Casimir Physics, edited by Diego Dalvit, Peter Milonni,
  David Roberts, and Felipe da Rosa. Minor changes, a reference adde
On the problem of van der Waals forces in dielectric media

A short review of the problems which arise in the generalization of the
Lifshitz theory of van der Waals force in the case of forces inside dielectric
media is presented, together with some historical remarks. General properties
of the stress tensor of equilibrium electromagnetic field in media are
discussed, and the importance of the conditions of mechanical equilibrium is
stressed. The physical meaning of the repulsive van der Waals interaction
between bodies immersed in a liquid is discussed.Comment: 10 pages, 2 figures. To be published in "Casimir Physics", Lecture
  Notes in Physics Series, Springe
Local and Global Casimir Energies: Divergences, Renormalization, and the
  Coupling to Gravity

From the beginning of the subject, calculations of quantum vacuum energies or
Casimir energies have been plagued with two types of divergences: The total
energy, which may be thought of as some sort of regularization of the
zero-point energy, $\sum\frac12\hbar\omega$, seems manifestly divergent. And
local energy densities, obtained from the vacuum expectation value of the
energy-momentum tensor, $\langle T_{00}\rangle$, typically diverge near
boundaries. The energy of interaction between distinct rigid bodies of whatever
type is finite, corresponding to observable forces and torques between the
bodies, which can be unambiguously calculated. The self-energy of a body is
less well-defined, and suffers divergences which may or may not be removable.
Some examples where a unique total self-stress may be evaluated include the
perfectly conducting spherical shell first considered by Boyer, a perfectly
conducting cylindrical shell, and dilute dielectric balls and cylinders. In
these cases the finite part is unique, yet there are divergent contributions
which may be subsumed in some sort of renormalization of physical parameters.
The divergences that occur in the local energy-momentum tensor near surfaces
are distinct from the divergences in the total energy, which are often
associated with energy located exactly on the surfaces. However, the local
energy-momentum tensor couples to gravity, so what is the significance of
infinite quantities here? For the classic situation of parallel plates there
are indications that the divergences in the local energy density are consistent
with divergences in Einstein's equations; correspondingly, it has been shown
that divergences in the total Casimir energy serve to precisely renormalize the
masses of the plates, in accordance with the equivalence principle.Comment: 53 pages, 1 figure, invited review paper to Lecture Notes in Physics
  volume in Casimir physics edited by Diego Dalvit, Peter Milonni, David
  Roberts, and Felipe da Ros
Casimir effect in the scattering approach: correlations between material
  properties, temperature and geometry

We present calculations of the quantum and thermal Casimir interaction
between real mirrors in electromagnetic fields using the scattering approach.
We begin with a pedagogical introduction of this approach in simple cases where
the scattering is specular. We then discuss the more general case of stationary
arbitrarily shaped mirrors and present in particular applications to two
geometries of interest for experiments, that is corrugated plates and the
plane-sphere geometry. The results nicely illustrate the rich correlations
existing between material properties, temperature and geometry in the Casimir
effect
Geometry and material effects in Casimir physics - Scattering theory

We give a comprehensive presentation of methods for calculating the Casimir
force to arbitrary accuracy, for any number of objects, arbitrary shapes,
susceptibility functions, and separations. The technique is applicable to
objects immersed in media other than vacuum, to nonzero temperatures, and to
spatial arrangements in which one object is enclosed in another. Our method
combines each object's classical electromagnetic scattering amplitude with
universal translation matrices, which convert between the bases used to
calculate scattering for each object, but are otherwise independent of the
details of the individual objects. This approach, which combines methods of
statistical physics and scattering theory, is well suited to analyze many
diverse phenomena. We illustrate its power and versatility by a number of
examples, which show how the interplay of geometry and material properties
helps to understand and control Casimir forces. We also examine whether
electrodynamic Casimir forces can lead to stable levitation. Neglecting
permeabilities, we prove that any equilibrium position of objects subject to
such forces is unstable if the permittivities of all objects are higher or
lower than that of the enveloping medium; the former being the generic case for
ordinary materials in vacuum.Comment: 44 pages, 11 figures, to appear in upcoming Lecture Notes in Physics
  volume in Casimir physic
Numerical Methods for Computing Casimir Interactions

We review several different approaches for computing Casimir forces and related fluctuation-induced interactions between bodies of arbitrary shapes and materials. The relationships between this problem and well known computational techniques from classical electromagnetism are emphasized. We also review the basic principles of standard computational methods, categorizing them according to three criteria\-choice of problem, basis, and solution technique\-that can be used to classify proposals for the Casimir problem as well. In this way, mature classical methods can be exploited to model Casimir physics, with a few important modifications.Keywords:
Imaginary Frequency, Perfectly Match Layer, Casimir Force, Casimir Energy, Perfect Electric ConductorUnited States. Army Research Office (Contract W911NF-07-D-0004)Massachusetts Institute of Technology. Ferry FundUnited States. Defense Advanced Research Projects Agency (Contract N66001-09-1-2070-DOD
Effective hybrid recommendation combining users-searches correlations using tensors

Most recommendation methods employ item-item similarity measures or use ratings data to generate recommendations. These methods use traditional two dimensional models to find inter relationships between alike users and products. This paper proposes a novel recommendation method using the multi-dimensional model, tensor, to group similar users based on common search behaviour, and then finding associations within such groups for making effective inter group recommendations. Web log data is multi-dimensional data. Unlike vector based methods, tensors have the ability to highly correlate and find latent relationships between such similar instances, consisting of users and searches. Non redundant rules from such associations of user-searches are then used for making recommendations to the users