title: The Reverse Cuthill-McKee Algorithm in Distributed-Memory

abstract:
  Ordering vertices of a graph is key to minimize fill-in and data structure
size in sparse direct solvers, maximize locality in iterative solvers, and
improve performance in graph algorithms. Except for naturally parallelizable
ordering methods such as nested dissection, many important ordering methods
have not been efficiently mapped to distributed-memory architectures. In this
paper, we present the first-ever distributed-memory implementation of the
reverse Cuthill-McKee (RCM) algorithm for reducing the profile of a sparse
matrix. Our parallelization uses a two-dimensional sparse matrix decomposition.
We achieve high performance by decomposing the problem into a small number of
primitives and utilizing optimized implementations of these primitives. Our
implementation shows strong scaling up to 1024 cores for smaller matrices and
up to 4096 cores for larger matrices.


title: Memshare: a Dynamic Multi-tenant Memory Key-value Cache

abstract:
  Web application performance is heavily reliant on the hit rate of
memory-based caches. Current DRAM-based web caches statically partition their
memory across multiple applications sharing the cache. This causes under
utilization of memory which negatively impacts cache hit rates. We present
Memshare, a novel web memory cache that dynamically manages memory across
applications. Memshare provides a resource sharing model that guarantees
private memory to different applications while dynamically allocating the
remaining shared memory to optimize overall hit rate. Today's high cost of DRAM
storage and the availability of high performance CPU and memory bandwidth, make
web caches memory capacity bound. Memshare's log-structured design allows it to
provide significantly higher hit rates and dynamically partition memory among
applications at the expense of increased CPU and memory bandwidth consumption.
In addition, Memshare allows applications to use their own eviction policy for
their objects, independent of other applications. We implemented Memshare and
ran it on a week-long trace from a commercial memcached provider. We
demonstrate that Memshare increases the combined hit rate of the applications
in the trace by an 6.1% (from 84.7% hit rate to 90.8% hit rate) and reduces the
total number of misses by 39.7% without affecting system throughput or latency.
Even for single-tenant applications, Memshare increases the average hit rate of
the current state-of-the-art memory cache by an additional 2.7% on our
real-world trace.


title: The highly ionized, high velocity gas in NGC 6231

abstract:
  It is well known that clusters of massive stars are influenced by the
presence of strong winds, that they are sources of diffuse X-rays from shocked
gas, and that this gas can be vented into the surrounding region or the halo
through the champagne effect. However, the details of how these different
environments interact and evolve are far from complete. This paper attributes
the broad C IV 1500 absorption features (extending to -1900 \kms) that are seen
in the spectra of main sequence B stars in NGC 6231 to gas in the cluster
environment and not the B stars themselves. It is shown that the presence of a
WC star, WR 79, in the cluster makes this gas detectable because its wind
enriches the cluster gas with carbon. Given the available data, it is not clear
whether the absorbing gas is simply the far wind of WR 79 or a collective
cluster wind enriched by carbon from the wind of WR 79. If it is simply due to
the wind, then this wind must flow, unimpeded for more than 2 pc, suggesting
that the inner region of the cluster is nearly devoid of obstructing material.
If it is actually a collective wind from the cluster, then we could be
witnessing an important stage of galactic feedback. In either case, the
observations provide a unique and significant piece to the puzzle of how
massive, open clusters evolve.


title:
Time in the theory of relativity: inertial time, light clocks, and
  proper time

abstract:
  In a way similar to classical mechanics where we have the concept of inertial
time as expressed in the motions of bodies, in the (special) theory of
relativity we can regard the inertial time as the only notion of time at play.
The inertial time is expressed also in the propagation of light. This gives
rise to a notion of clock, the light clock, which we can regard as a notion
derived from the inertial time. The light clock can be seen as a solution of
the theory, which complies with the requirement that a clock to be so must have
a rate that is independent of its past history. Contrary to Einstein's view, we
do not need the concept of clock as an independent concept. This implies, in
particular, that we do not need to rely on the notions of atomic clock or
atomic time in the theory of relativity.


title: Magnetic field amplification in turbulent astrophysical plasmas

abstract:
  Magnetic fields play an important role in astrophysical accretion discs, and
in the interstellar and intergalactic medium. They drive jets, suppress
fragmentation in star-forming clouds and can have a significant impact on the
accretion rate of stars. However, the exact amplification mechanisms of cosmic
magnetic fields remain relatively poorly understood. Here I start by reviewing
recent advances in the numerical and theoretical modelling of the 'turbulent
dynamo', which may explain the origin of galactic and inter-galactic magnetic
fields. While dynamo action was previously investigated in great detail for
incompressible plasmas, I here place particular emphasis on highly compressible
astrophysical plasmas, which are characterised by strong density fluctuations
and shocks, such as the interstellar medium. I find that dynamo action works
not only in subsonic plasmas, but also in highly supersonic, compressible
plasmas, as well as for low and high magnetic Prandtl numbers. I further
present new numerical simulations from which I determine the growth of the
turbulent (un-ordered) magnetic field component ($B_\mathrm{turb}$) in the
presence of weak and strong guide fields ($B_0$). I vary $B_0$ over 5 orders of
magnitude and find that the dependence of $B_\mathrm{turb}$ on $B_0$ is
relatively weak, and can be explained with a simple theoretical model in which
the turbulence provides the energy to amplify $B_\mathrm{turb}$. Finally, I
discuss some important implications of magnetic fields for the structure of
accretion discs, the launching of jets, and the star formation rate of
interstellar clouds.

categories: physics.plasm-ph astro-ph.GA astro-ph.SR physics.flu-dyn


title:
Incremental Nonparametric Weighted Feature Extraction for OnlineSubspace
  Pattern Classification

abstract:
  In this paper, a new online method based on nonparametric weighted feature
extraction (NWFE) is proposed. NWFE was introduced to enjoy optimum
characteristics of linear discriminant analysis (LDA) and nonparametric
discriminant analysis (NDA) while rectifying their drawbacks. It emphasizes the
points near decision boundary by putting greater weights on them and
deemphasizes other points. Incremental nonparametric weighted feature
extraction (INWFE) is the online version of NWFE. INWFE has advantages of NWFE
method such as extracting more than L-1 features in contrast to LDA. It is
independent of the class distribution and performs well in complex distributed
data. The effects of outliers are reduced due to the nature of its
nonparametric scatter matrix. Furthermore, it is possible to add new samples
asynchronously, i.e. whenever a new sample becomes available at any given time,
it can be added to the algorithm. This is useful for many real world
applications since all data cannot be available in advance. This method is
implemented on Gaussian and non-Gaussian multidimensional data, a number of UCI
datasets and Indian Pine dataset. Results are compared with NWFE in terms of
classification accuracy and execution time. For nearest neighbour classifier it
shows that this technique converges to NWFE at the end of learning process. In
addition, the computational complexity is reduced in comparison with NWFE in
terms of execution time.


title:
Kinetic corrections from analytic non-Maxwellian distribution functions
  in magnetized plasmas

abstract:
  In magnetized plasma physics, almost all developed analytic theories assume a
Maxwellian distribution function (MDF) and in some cases small deviations are
described using the perturbation theory. The deviations with respect to the
Maxwellian equilibrium, called kinetic effects, are required to be taken into
account specially for fusion reactor plasmas. Generally, because the
perturbation theory is not consistent with observed steady-state
non-Maxwellians, these kinetic effects are numerically evaluated by very
CPU-expensive codes, avoiding the analytic complexity of velocity phase space
integrals. We develop here a new method based on analytic non-Maxwellian
distribution functions constructed from non-orthogonal basis sets in order to
(i) use as few parameters as possible, (ii) increase the efficiency to model
numerical and experimental non-Maxwellians, (iii) help to understand unsolved
problems such as diagnostics discrepancies from the physical interpretation of
the parameters, and (iv) obtain analytic corrections due to kinetic effects
given by a small number of terms and removing the numerical error of the
evaluation of velocity phase space integrals. This work does not attempt to
derive new physical effects even if it could be possible to discover one from
the better understandings of some unsolved problems, but here we focus on the
analytic prediction of kinetic corrections from analytic non-Maxwellians. As
applications, examples of analytic kinetic corrections are shown for the
secondary electron emission, the Langmuir probe characteristic curve, and the
entropy. This is done by using three analytic representations of the
distribution function: the Kappa (KDF), the bi-modal or a new interpreted
non-Maxwellian (INMDF) distribution function. [...]

categories: physics.plasm-ph physics.acc-ph physics.atom-ph physics.space-ph


title:
A Matrix Method for Quasinormal Modes: Schwarzschild Black Holes in
  Asymptotically Flat and (Anti-) de Sitter Spacetimes

abstract:
  In this work, we study the quasinormal modes of Schwarzschild and
Schwarzschild (Anti-) de Sitter black holes by a matrix method. The proposed
method involves discretizing the master field equation and expressing it in
form of a homogeneous system of linear algebraic equations. The resulting
homogeneous matrix equation furnishes a non-standard eigenvalue problem, which
can then be solved numerically to obtain the quasinormal frequencies. A key
feature of the present approach is that the discretization of the wave function
and its derivatives are made to be independent of any specific metric through
coordinate transformation. In many cases, it can be carried out beforehand
which in turn improves the efficiency and facilitates the numerical
implementation. We also analyze the precision and efficiency of the present
method as well as compare the results to those obtained by different
approaches.


title:
Learning to Match Using Local and Distributed Representations of Text
  for Web Search

abstract:
  Models such as latent semantic analysis and those based on neural embeddings
learn distributed representations of text, and match the query against the
document in the latent semantic space. In traditional information retrieval
models, on the other hand, terms have discrete or local representations, and
the relevance of a document is determined by the exact matches of query terms
in the body text. We hypothesize that matching with distributed representations
complements matching with traditional local representations, and that a
combination of the two is favorable. We propose a novel document ranking model
composed of two separate deep neural networks, one that matches the query and
the document using a local representation, and another that matches the query
and the document using learned distributed representations. The two networks
are jointly trained as part of a single neural network. We show that this
combination or `duet' performs significantly better than either neural network
individually on a Web page ranking task, and also significantly outperforms
traditional baselines and other recently proposed models based on neural
networks.


title:
Oscillatory deviations from Matthiessen's rule due to interacting
  dislocations

abstract:
  We theoretically examine the validity of Matthiessen's rule caused by strong
dislocation-dislocation interaction using a fully quantized dislocation field,
where its degree of deviation is quantified at arbitrary electron energy,
dislocation-electron and dislocation-dislocation distances and interaction
strengths. Contrary to intuition, we show that the electron relaxation rate
deviates from the Matthiessen's rule in an oscillatory way as a function of
inter-dislocation distance, instead of monotonically. This study could serve as
a computational tool to investigate the electronic behavior of a
highly-dislocated system at a full quantum field theoretical level.


title:
A BMO theorem for $\epsilon$ distorted diffeomorphisms from $\mathbb
  R^D$ to $\mathbb R^D$ with applications to manifolds of speech and sound

abstract:
  This paper deals with a BMO Theorem for $\epsilon$ distorted diffeomorphisms
from $\mathbb R^D$ to $\mathbb R^D$ with applications to manifolds of speech
and sound.


title: Neutron stars in the light of SKA: Data, statistics, and science

abstract:
  The Square Kilometre Array (SKA), when it becomes functional, is expected to
enrich neutron star (NS) catalogues by at least an order of magnitude over
their current state. This includes the discovery of new NS objects leading to
better sampling of under-represented NS categories, precision measurements of
intrinsic properties such as spin period and magnetic field, as also data on
related phenomena such as microstructure, nulling, glitching, etc. This will
present a unique opportunity to seek answers to interesting and fundamental
questions about the extreme physics underlying these exotic objects in the
universe. In this paper, we first present a meta-analysis (from a
methodological viewpoint) of statistical analyses performed using existing NS
data, with a two-fold goal: First, this should bring out how statistical models
and methods are shaped and dictated by the science problem being addressed.
Second, it is hoped that these analyses will provide useful starting points for
deeper analyses involving richer data from SKA whenever it becomes available.
We also describe a few other areas of NS science which we believe will benefit
from SKA which are of interest to the Indian NS community.


title:
Extended Klein model and a bound on curves with negative
  self-intersection

abstract:
  Let $S$ be an irreducible smooth projective surface and $\mathcal{F}$ a
collection of curves with negative self-intersection on $S$ such that no
positive combination $aC_1 + bC_2$ is connected nef. In this paper, we provide
an alternate proof that $\mathcal{F}$ is bounded by an exponential function of
the Picard number $\rho(S)$ of $S$ using an extended version of the Klein disc
model for hyperbolic space.


title:
The index of Callias-type operators with Atiyah-Patodi-Singer boundary
  conditions

abstract:
  We compute the index of a Callias-type operator with APS boundary condition
on a manifold with compact boundary in terms of combination of indexes of
induced operators on a compact hypersurface. Our result generalizes the
classical Callias-type index theorem to manifolds with compact boundary.


title:
Measurement of forward $t\overline{t}$, $W+b\overline{b}$ and
  $W+c\overline{c}$ production in $pp$ collisions at $\sqrt{s}=8$ TeV

abstract:
  The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is
studied in the forward region of proton-proton collisions collected at a
centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an
integrated luminosity of 1.98 $\pm$ 0.02 $\mbox{fb}^{-1}$. The $W$ bosons are
reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or
electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured
cross-sections are in agreement with next-to-leading-order Standard Model
predictions.


title:
Optimal Risk-Averse Timing of an Asset Sale: Trending vs Mean-Reverting
  Price Dynamics

abstract:
  This paper studies the optimal risk-averse timing to sell a risky asset. The
investor's risk preference is described by the exponential, power, or log
utility. Two stochastic models are considered for the asset price -- the
geometric Brownian motion and exponential Ornstein-Uhlenbeck models -- to
account for, respectively, the trending and mean-reverting price dynamics. In
all cases, we derive the optimal thresholds and certainty equivalents to sell
the asset, and compare them across models and utilities, with emphasis on their
dependence on asset price, risk aversion, and quantity. We find that the timing
option may render the investor's value function and certainty equivalent
non-concave in price. Numerical results are provided to illustrate the
investor's strategies and the premium associated with optimally timing to sell.


title:
Departure from Equilibrium of the Quasi-Particle Distribution Functions
  in High Energy Nuclear Collisions

abstract:
  In simulations of high energy heavy ion collisions that employ viscous
hydrodynamics, single particle distributions are distorted from their thermal
equilibrium form due to gradients in the flow velocity. These are closely
related to the formulas for the shear and bulk viscosities in the
quasi-particle approximation. Distorted single particle distributions are now
commonly used to calculate the emission of photons and dilepton pairs, and in
the late stage to calculate the conversion of a continuous fluid to individual
particles. We show how distortions of the single particle distribution
functions due to both shear and bulk viscous effects can be done rigorously in
the quasi-particle approximation and illustrate it with the linear $\sigma$
model at finite temperature.


title: Single-mode dispersive waves and soliton microcomb dynamics

abstract:
  Dissipative Kerr solitons are self-sustaining optical wavepackets in
resonators. They use the Kerr nonlinearity to both compensate dispersion and to
offset optical loss. Besides providing insights into nonlinear resonator
physics, they can be applied in frequency metrology, precision clocks, and
spectroscopy. Like other optical solitons, the dissipative Kerr soliton can
radiate power in the form of a dispersive wave through a process that is the
optical analogue of Cherenkov radiation. Dispersive waves typically consist of
an ensemble of optical modes. A limiting case is demonstrated in which the
dispersive wave is concentrated into a single cavity mode. In this limit, its
interaction with the soliton is shown to induce bistable behavior in the
spectral and temporal properties of the soliton. Also, an operating point of
enhanced repetition-rate stability is predicted and observed. The single-mode
dispersive wave can therefore provide quiet states of soliton comb operation
useful in many applications.


title:
von Neumann measurement-related matrices and the nullity condition for
  quantum correlation

abstract:
  We study von Neumann measurement-related matrices, and the nullity condition
of quantum correlation. We investigate the properties of these matrices that
are related to a von Neumann measurement. It is shown that these (m^2-1)*
(m^2-1) matrices are idempotent, and have rank m-1. These properties give rise
to necessary conditions for the nullity of quantum correlations in bipartite
systems. Finally, as an example we discuss quantum correlation in Bell diagonal
states.


title: Maximally entangled state and fully entangled fraction

abstract:
  We study maximally entangled states and fully entangled fraction in general
d'\otimes d (d'\geq d) systems. Necessary and sufficient conditions for
maximally entangled pure and mixed states are presented. As a natural
generalization of the usual fully entangled fraction for d\otimes d systems, we
define the maximal overlap between a given quantum state and the maximally
entangled states as the fully entangled fraction in d'\otimes d systems. The
properties of this fully entangled fraction and its relations to quantum
teleportation have been analyzed. The witness for detecting maximally entangled
states and quantum states that are useful for quantum teleportation is
provided.


title:
Online Bayesian phylogenetic inference: theoretical foundations via
  Sequential Monte Carlo

abstract:
  Phylogenetics, the inference of evolutionary trees from molecular sequence
data such as DNA, is an enterprise that yields valuable evolutionary
understanding of many biological systems. Bayesian phylogenetic algorithms,
which approximate a posterior distribution on trees, have become a popular if
computationally expensive means of doing phylogenetics. Modern data collection
technologies are quickly adding new sequences to already substantial databases.
With all current techniques for Bayesian phylogenetics, computation must start
anew each time a sequence becomes available, making it costly to maintain an
up-to-date estimate of a phylogenetic posterior. These considerations highlight
the need for an \emph{online} Bayesian phylogenetic method which can update an
existing posterior with new sequences.
  Here we provide theoretical results on the consistency and stability of
methods for online Bayesian phylogenetic inference based on Sequential Monte
Carlo (SMC) and Markov chain Monte Carlo (MCMC). We first show a consistency
result, demonstrating that the method samples from the correct distribution in
the limit of a large number of particles. Next we derive the first reported set
of bounds on how phylogenetic likelihood surfaces change when new sequences are
added. These bounds enable us to characterize the theoretical performance of
sampling algorithms by bounding the effective sample size (ESS) with a given
number of particles from below. We show that the ESS is guaranteed to grow
linearly as the number of particles in an SMC sampler grows. Surprisingly, this
result holds even though the dimensions of the phylogenetic model grow with
each new added sequence.


title:
Undercover EUV Solar Jets Observed by the Interface Region Imaging
  Spectrograph

abstract:
  It is well-known that extreme ultraviolet emission emitted at the solar
surface is absorbed by overlying cool plasma. Especially in active regions dark
lanes in EUV images suggest that much of the surface activity is obscured.
Simultaneous observations from IRIS, consisting of UV spectra and slit-jaw
images give vital information with sub-arcsecond spatial resolution on the
dynamics of jets not seen in EUV images. We studied a series of small jets from
recently formed bipole pairs beside the trailing spot of active region 11991,
which occurred on 2014 March 5 from 15:02:21 UT to 17:04:07 UT. There were
collimated outflows with bright roots in the SJI 1400 {\AA} (transition region)
and 2796 {\AA} (upper chromosphere) that were mostly not seen in AIA 304 {\AA}
(transition region) and AIA 171 \AA\ (lower corona) images. The Si IV spectra
show strong blue-wing but no red-wing enhancements in the line profiles of the
ejecta for all recurrent jets indicating outward flows without twists. We see
two types of Mg II line profiles produced by the jets spires: reversed and
non-reversed. Mg II lines remain optically thick but turn into optically thin
in the highly Doppler shifted wings.The energy flux contained in each recurrent
jet is estimated using a velocity differential emission measure technique which
measures the emitting power of the plasma as a function of line-of-sight
velocity. We found that all the recurrent jets release similar energy (10$^8$
erg cm$^{-2}$ s$^{-1}$ ) toward the corona and the downward component is less
than 3\%.


title:
Polarizabilities and tune-out wavelengths of the hyperfine ground states
  of $^{87,85}$Rb

abstract:
  The static and dynamic polarizabilities, and the tune-out wavelengths of the
ground state of Rb and the hyperfine ground states of $^{87, 85}$Rb have been
calculated by using relativistic configuration interaction plus core
polarization(RCICP) approach. It is found that the first primary tune-out
wavelengths of the $ 5s_{1/2}, F=1, 2 $ states of $ ^{87}$Rb are
790.018187(193) nm and 790.032602(193) nm severally, where the calculated
result for the $ 5s_{1/2}, F=2 $ state is in good agreement with the latest
high-precision measurement 790.032388(32) nm [Phys. Rev. A 92, 052501 (2015)].
Similarly, the first primary tune-out wavelengths of the $ 5s_{1/2}, F=2, 3 $
states of $^{85}$Rb are 790.023515(218) nm and 790.029918(218) nm respectively.
Furthermore, the tune-out wavelengths for the different magnetic sublevels $
M_{F}$ of each hyperfine level $F$ are also determined by considering the
contributions of tensor polarizabilities.


title: Monotonicity of the speed for biased random walk on Galton-Watson tree

abstract:
  Ben Arous, Fribergh and Sidoravicius \cite{GAV2014} proved that speed of
biased random walk $RW_\lambda$ on a Galton-Watson tree without leaves is
strictly decreasing for $\lambda\leq \frac{m_1}{1160},$ where $m_1$ is minimal
degree of the Galton-Watson tree. And A\"{\i}d\'{e}kon \cite{EA2013} improved
this result to $\lambda\leq \frac{1}{2}.$ In this paper, we prove that for the
$RW_{\lambda}$ on a Galton-Watson tree without leaves, its speed is strictly
decreasing for $\lambda\in \left[0,\frac{m_1}{1+\sqrt{1-\frac{1}{m_1}}}\right]$
when $m_1\geq 2;$ and we owe the proof to A\"{\i}d\'{e}kon \cite{EA2013}.


title:
Cost Efficiency for Economical Mobile Data Traffic Management from
  Users' Perspective

abstract:
  Explosive demand for wireless internet services has posed critical challenges
for wireless network due to its limited capacity. To tackle this hurdle,
wireless Internet service providers (WISPs) take the smart data pricing to
manage data traffic loads. Meanwhile, from the users' perspective, it is also
reasonable and desired to employ mobile data traffic management under the
pricing policies of WISPs to improve the economic efficiency of data
consumption. In this paper we introduce a concept of cost efficiency for user's
mobile data management, defined as the ratio of user's mobile data consumption
benefits and its expense. We propose an integrated cost-efficiency-based data
traffic management scheme including long-term data demand planning, short-term
data traffic pre-scheduling and real-time data traffic management. The
real-time data traffic management algorithm is proposed to coordinate user's
data consumption to tailor to the pre-scheduled data traffic profile. Numerical
results demonstrate the effectiveness of cost efficiency framework in
indicating and motivating mobile user's data consumption behavior. The proposed
management scheme can effectively motivate the user to adjust its data
consumption profile to obtain the optimal data consumption cost efficiency.


title: On intersecting families of independent sets in trees

abstract:
  A family of sets is intersecting if every pair of its sets intersect. A star
is a family with some element (a center) in each of its sets. The classical
1961 result of Erd\H{o}s, Ko, and Rado states that every intersecting family of
r-sets with $r\leq n/2$ has size at most that of a star. We say that graph G is
r-EKR if, among all intersecting families of independent r-sets of G, the
largest is attained by a star. In 2005 Holroyd and Talbot conjectured that
every graph G is r-EKR for all $1\leq r\leq \mu(G)/2$, where $\mu(G)$ is the
size of the smallest maximal independent set in G. We verified the conjecture
in 2011 for all chordal graphs containing an isolated vertex.
  For graphs without isolated vertices it is difficult to determine the center
of the largest star, which is often necessary to prove that they are EKR. A
tree has the leaf property if its largest star occurs on one of its leaves. We
proved that every tree T has the leaf property when $r\leq 4$, and in 2017 Borg
and other authors gave examples of families of trees not having the leaf
property when $r\geq 5$. A split vertex in a tree is a vertex of degree at
least 3. A spider is a tree with exactly one split vertex. Here we prove that
all spiders have the leaf property for all $r\leq \alpha(G)$, where $\alpha(G)$
is the independence number of $G$, and we characterize which of its leaves are
maximum star centers. A pendant tree is one for which each of its split
vertices is adjacent to a leaf. Here we show that all pendant trees have the
leaf property for all $r\leq \alpha(G)$. We also consider pendant trees with
exactly two split vertices and provide partial results on the locations of
their maximum star centers.


title:
LP Rounding and Combinatorial Algorithms for Minimizing Active and Busy
  Time

abstract:
  We consider fundamental scheduling problems motivated by energy issues. In
this framework, we are given a set of jobs, each with a release time, deadline
and required processing length. The jobs need to be scheduled on a machine so
that at most g jobs are active at any given time. The duration for which a
machine is active (i.e., "on") is referred to as its active time. The goal is
to find a feasible schedule for all jobs, minimizing the total active time.
When preemption is allowed at integer time points, we show that a minimal
feasible schedule already yields a 3-approximation (and this bound is tight)
and we further improve this to a 2-approximation via LP rounding techniques.
Our second contribution is for the non-preemptive version of this problem.
However, since even asking if a feasible schedule on one machine exists is
NP-hard, we allow for an unbounded number of virtual machines, each having
capacity of g. This problem is known as the busy time problem in the literature
and a 4-approximation is known for this problem. We develop a new combinatorial
algorithm that gives a 3-approximation. Furthermore, we consider the preemptive
busy time problem, giving a simple and exact greedy algorithm when unbounded
parallelism is allowed, i.e., g is unbounded. For arbitrary g, this yields an
algorithm that is 2-approximate.


title: Oscillation of generalized differences of H\"older and Zygmund functions

abstract:
  In this paper we analyze the oscillation of functions having derivatives in
the H\"older or Zygmund class in terms of generalized differences and prove
that its growth is governed by a version of the classical Kolmogorov's Law of
the Iterated Logarithm. A better behavior is obtained for functions in the
Lipschitz class via an interesting connection with Calder\'on-Zygmund
operators.


title: On the number of generators of an algebra

abstract:
  A classical theorem of Forster asserts that a finite module $M$ of rank $\leq
n$ over a Noetherian ring of Krull dimension $d$ can be generated by $n + d$
elements. We prove a generalization of this result, with "module" replaced by
"algebra". Here we allow arbitrary finite algebras, not necessarily unital,
commutative or associative. Forster's theorem can be recovered as a special
case by viewing a module as an algebra where the product of any two elements is
$0$.


title:
Impact of Fe site Co substitution on superconductivity of
  Fe1-xCoxSe0.5Te0.5 (x = 0.0 to 0.10): A flux free single crystal study

abstract:
  We report synthesis of Co substitution at Fe site in Fe1-xCoxSe0.5Te0.5
(x=0.0 to 0.10) single crystals via vacuum shield solid state reaction route
using flux free method. Single crystal XRD results showed that these crystals
grow in (00l) plane i.e., orientation in c-direction. All the crystals possess
tetragonal structure having P4/nmm space group. Detailed scanning electron
microscopy (SEM) images show that the crystals are grown in slab-like
morphology. The EDAX results revealed the final elemental composition to be
near stoichiometric. Powder X-Ray diffraction (PXRD) Rietveld analysis results
show that (00l) peaks are shifted towards higher angle with increasing Co
concentration. Both a and c lattice parameters decrease with increasing Co
concentration in Fe1-xCoxSe0.5Te0.5 (x=0.0 to 0.10) single crystals. Low
temperature transport and magnetic measurements show that the superconducting
transition temperature (Tc), decreases from around 12K to 10K and 4K for x=0.03
and x=0.05 respectively. For x=0.10 crystal superconductivity is not observed
down to 2K.


title: Quantum radiation produced by the entanglement of quantum fields

abstract:
  We investigate the quantum radiation produced by an Unruh-De Witt detector in
a uniformly accelerating motion coupled to the vacuum fluctuations. Quantum
radiation is nonvanishing, which is consistent with the previous calculation by
Lin and Hu [Phys. Rev. D 73, 124018 (2006)]. We infer that this quantum
radiation from the Unruh-De Witt detector is generated by the nonlocal
correlation of the Minkowski vacuum state, which has its origin in the
entanglement of the state between the left and the right Rindler wedges.


title: A Note on a result due to Ankeny and Rivlin

abstract:
  Let $p(z)=a_0+a_1z+a_2z^2+a_3z^3+\cdots+a_nz^n$ be a polynomial of degree $n$
having no zeros in the unit disk. ~Then it is well known that for $R\geq 1,$
$\displaystyle{\max_{|z|=R}|p(z)|}\leq
\Big(\dfrac{R^n+1}{2}\Big)\displaystyle{\max_{|z|=1}|p(z)|}.$ In this paper, we
consider polynomials with gaps, having all its zeros on the circle $S(0,
K):=\{z: |z|=K\}, ~0<K\le 1,$~ and estimate the value of
$\Big(\dfrac{{\max_{|z|=R}|p(z)|}}{{\max_{|z|=1}|p(z)|}}\Big)^s$ for any
positive integer $s.$


title: A uniform estimate for rate functions in large deviations

abstract:
  Given H\"older continuous functions $f$ and $\psi$ on a sub-shift of finite
type $\Sigma_A^{+}$ such that $\psi$ is not cohomologous to a constant, the
classical large deviation principle holds (\cite{OP}, \cite{Kif}, \cite{Y})
with a rate function $I_\psi\geq 0$ such that $I_\psi (p) = 0$ iff $p = \int
\psi \, d \mu$, where $\mu = \mu_f$ is the equilibrium state of $f$. In this
paper we derive a uniform estimate from below for $I_\psi$ for $p$ outside an
interval containing $\tilde{\psi} = \int \psi \, d\mu$, which depends only on
the sub-shift, the function $f$, the norm $|\psi|_\infty$, the H\"older
constant of $\psi$ and the integral $\tilde{\psi}$. Similar results can be
derived in the same way e.g. for Axiom A diffeomorphisms on basic sets.


title:
Finite groups determined by an inequality of the orders of their
  subgroups II

abstract:
  In this note we study a class of finite groups for which the orders of
subgroups satisfy a certain inequality. In particular, characterizations of the
well-known groups $\mathbb{Z}_2\times\mathbb{Z}_2$ and $S_3$ are obtained.


title: On Lawson-Osserman Constructions

abstract:
  Lawson-Osserman constructed three types of non-parametric minimal cones of
high codimensions based on Hopf maps between spheres, which correspond to
Lipschitz but non-differentiable solutions to the minimal surface equations,
thereby making sharp contrast to the regularity theorem for minimal graphs of
codimension 1. In this paper, we develop the constructions in a more general
scheme. Once a mapping f between unit spheres is composited of a harmonic
Riemannian submersion and a homothetic (i.e., up to a constant factor,
isometric) minimal immersion, certain twisted graph of f can yield a
non-parametric minimal cone. Because the choices of the second component
usually form a huge moduli space, our constructions produce a constellation of
uncountably many examples. For each such cone, there exists an entire minimal
graph whose tangent cone at infinity is just the given one. Moreover, new
phenomena on the existence, non-uniqueness and non-minimizing of solutions to
the related Dirichlet problem are discovered.


title: Phenotypic heterogeneity in modeling cancer evolution

abstract:
  The unwelcome evolution of malignancy during cancer progression emerges
through a selection process in a complex heterogeneous population structure. In
the present work, we investigate evolutionary dynamics in a phenotypically
heterogeneous population of stem cells (SCs) and their associated progenitors.
The fate of a malignant mutation is determined not only by overall stem cell
and differentiated cell growth rates but also differentiation and
dedifferentiation rates. We investigate the effect of such a complex population
structure on the evolution of malignant mutations. We derive exact analytic
results for the fixation probability of a mutant arising in each of the
subpopulations. The analytic results are in almost perfect agreement with the
numerical simulations. Moreover, a condition for evolutionary advantage of a
mutant cell versus the wild type population is given in the present study. We
also show that microenvironment-induced plasticity in invading mutants leads to
more aggressive mutants with higher fixation probability. Our model predicts
that decreasing polarity between stem and differentiated cells turnover would
raise the survivability of non-plastic mutants; while it would suppress the
development of malignancy for plastic mutants. We discuss our model in the
context of colorectal/intestinal cancer (at the epithelium). This novel
mathematical framework can be applied more generally to a variety of problems
concerning selection in heterogeneous populations, in other contexts such as
population genetics, and ecology.


title:
Glass transitions, semiconductor-metal (SC-M) transitions and
  fragilities in Ge-V-Te (V=As, or Sb) liquid alloys: the difference one
  element can make

abstract:
  Glass transition temperatures (Tg) and liquid fragilities are measured along
a line of constant Ge content in the system Ge-As-Te, and contrasted with the
lack of glass-forming ability in the twin system Ge-Sb-Te at the same Ge
content. The one composition established as free of crystal contamination in
the latter system shows a behavior opposite to that of more covalent system.
Comparison of Tg vs bond density in the three systems Ge-As-chalcogen differing
in chalcogen i.e. S, Se, or Te, shows that as the chalcogen becomes more
metallic, i.e. in the order S<Se<Te the bond density effect on Tg becomes
systematically weaker, with a crossover at <r> = 2.3. When the more metallic Sb
replaces As at <r> greater than 2.3, incipient metallicity rather than
directional bond covalency apparently gains control of the physics. This leads
us to an examination of the electronic conductivity and, then,
semiconductor-to-metal (SC-M) transitions, with their associated thermodynamic
manifestations, in relevant liquid alloys. The thermodynamic components, as
seen previously, control liquid fragility and cause fragile-to-strong
transitions during cooling. We tentatively conclude that liquid state behavior
in phase change materials (PCMs) is controlled by liquid-liquid (SC-M)
transitions that have become submerged below the liquidus surface. In the case
of the Ge-Te binary, a crude extrapolation to GeTe stoichiometry indicates that
the SC-M transition lies about 20% below the melting point, suggesting a
parallel with the intensely researched "hidden liquid-liquid (LL) transition",
in supercooled water. In the water case, superfast crystallization initiates in
the high fragility domain some 4% above the TLL which is located at ~15% below
the (ambient pressure) melting point.


title: Hyperbolic Shirts fit a 4-body Problem

abstract:
  Consider the equal mass planar $4$-body problem with a potential
corresponding to an inverse \textit{cube} force. The Jacobi-Maupertuis
principle reparametrizes the dynamics as geodesics of a certain metric. We
examine the curvature of this geodesic flow in the reduced space on the
collinear and parallelogram invariant surfaces and derive some dynamical
consequences. This proves a numerical conjecture of [4].


title: Automatic measurement of vowel duration via structured prediction

abstract:
  A key barrier to making phonetic studies scalable and replicable is the need
to rely on subjective, manual annotation. To help meet this challenge, a
machine learning algorithm was developed for automatic measurement of a widely
used phonetic measure: vowel duration. Manually-annotated data were used to
train a model that takes as input an arbitrary length segment of the acoustic
signal containing a single vowel that is preceded and followed by consonants
and outputs the duration of the vowel. The model is based on the structured
prediction framework. The input signal and a hypothesized set of a vowel's
onset and offset are mapped to an abstract vector space by a set of acoustic
feature functions. The learning algorithm is trained in this space to minimize
the difference in expectations between predicted and manually-measured vowel
durations. The trained model can then automatically estimate vowel durations
without phonetic or orthographic transcription. Results comparing the model to
three sets of manually annotated data suggest it out-performed the current gold
standard for duration measurement, an HMM-based forced aligner (which requires
orthographic or phonetic transcription as an input).


title: Sound Probabilistic #SAT with Projection

abstract:
  We present an improved method for a sound probabilistic estimation of the
model count of a boolean formula under projection. The problem solved can be
used to encode a variety of quantitative program analyses, such as concerning
security of resource consumption. We implement the technique and discuss its
application to quantifying information flow in programs.


title: Location Aggregation of Spatial Population CTMC Models

abstract:
  In this paper we focus on spatial Markov population models, describing the
stochastic evolution of populations of agents, explicitly modelling their
spatial distribution, representing space as a discrete, finite graph. More
specifically, we present a heuristic approach to aggregating spatial locations,
which is designed to preserve the dynamical behaviour of the model whilst
reducing the computational cost of analysis. Our approach combines stochastic
approximation ideas (moment closure, linear noise), with computational
statistics (spectral clustering) to obtain an efficient aggregation, which is
experimentally shown to be reasonably accurate on two case studies: an instance
of epidemic spreading and a London bike sharing scenario.


title: Logical Characterization of Bisimulation Metrics

abstract:
  Bisimulation metrics provide a robust and accurate approach to study the
behavior of nondeterministic probabilistic processes. In this paper, we propose
a logical characterization of bisimulation metrics based on a simple
probabilistic variant of the Hennessy-Milner logic. Our approach is based on
the novel notions of mimicking formulae and distance between formulae. The
former are a weak version of the well known characteristic formulae and allow
us to characterize also (ready) probabilistic simulation and probabilistic
bisimilarity. The latter is a 1-bounded pseudometric on formulae that mirrors
the Hausdorff and Kantorovich lifting the defining bisimilarity pseudometric.
We show that the distance between two processes equals the distance between
their own mimicking formulae.


title: Parameterized Dataflow (Extended Abstract)

abstract:
  Dataflow networks have application in various forms of stream processing, for
example for parallel processing of multimedia data. The description of dataflow
graphs, including their firing behavior, is typically non-compositional and not
amenable to separate compilation. This article considers a dataflow language
with a type and effect system that captures the firing behavior of actors. This
system allows definitions to abstract over actor firing rates, supporting the
definition and safe composition of actor definitions where firing rates are not
instantiated until a dataflow graph is launched.


title: MELA: Modelling in Ecology with Location Attributes

abstract:
  Ecology studies the interactions between individuals, species and the
environment. The ability to predict the dynamics of ecological systems would
support the design and monitoring of control strategies and would help to
address pressing global environmental issues. It is also important to plan for
efficient use of natural resources and maintenance of critical ecosystem
services. The mathematical modelling of ecological systems often includes
nontrivial specifications of processes that influence the birth, death,
development and movement of individuals in the environment, that take into
account both biotic and abiotic interactions. To assist in the specification of
such models, we introduce MELA, a process algebra for Modelling in Ecology with
Location Attributes. Process algebras allow the modeller to describe concurrent
systems in a high-level language. A key feature of concurrent systems is that
they are composed of agents that can progress simultaneously but also interact
- a good match to ecological systems. MELA aims to provide ecologists with a
straightforward yet flexible tool for modelling ecological systems, with
particular emphasis on the description of space and the environment. Here we
present four example MELA models, illustrating the different spatial
arrangements which can be accommodated and demonstrating the use of MELA in
epidemiological and predator-prey scenarios.


title: Evaluating load balancing policies for performance and energy-efficiency

abstract:
  Nowadays, more and more increasingly hard computations are performed in
challenging fields like weather forecasting, oil and gas exploration, and
cryptanalysis. Many of such computations can be implemented using a computer
cluster with a large number of servers. Incoming computation requests are then,
via a so-called load balancing policy, distributed over the servers to ensure
optimal performance. Additionally, being able to switch-off some servers during
low period of workload, gives potential to reduced energy consumption.
Therefore, load balancing forms, albeit indirectly, a trade-off between
performance and energy consumption. In this paper, we introduce a syntax for
load-balancing policies to dynamically select a server for each request based
on relevant criteria, including the number of jobs queued in servers, power
states of servers, and transition delays between power states of servers. To
evaluate many policies, we implement two load balancers in: (i) iDSL, a
language and tool-chain for evaluating service-oriented systems, and (ii) a
simulation framework in AnyLogic. Both implementations are successfully
validated by comparison of the results.


title:
Controlled Barrage Regions: Stochastic Modeling, Analysis, and
  Optimization

abstract:
  A barrage relay network (BRN) is a broadcast oriented ad hoc network
involving autonomous cooperative communication, a slotted time-division frame
format, and a coarse slot-level synchronization. While inherently a broadcast
protocol, BRNs can support unicast transmission by superimposing a plurality of
controlled barrage regions (CBRs) onto the network. Within each CBRs, a new
packet is injected by the unicast source during the first time slot of each new
radio frame. When a CBRs is sufficiently long that a packet might not be able
to reach the other end within a radio frame, multiple packets can be active at
the same time via spatial pipelining, resulting in interference within the
CBRs. In this paper, the dynamics of packet transmission within a CBRs is
described as a Markov process, and the outage probability of each link within
the CBRs is evaluated in closed form, thereby accounting for fading and
co-channel interference. In order to account for the linkage between
simultaneous active packets and their temporal correlation, a Viterbi-like
algorithm is used. Using this accurate analytical framework, a line network is
optimized, which identifies the code rate, the number of relays, and the length
of a radio frame that maximizes the transport capacity.


title:
From Nearby Low Luminosity AGN to High Redshift Radio Galaxies: Science
  Interests with SKA

abstract:
  We present detailed science cases that a large fraction of the Indian AGN
community is interested in pursuing with the upcoming Square Kilometre Array
(SKA). These interests range from understanding low luminosity active galactic
nuclei in the nearby Universe to powerful radio galaxies at high redshifts.
Important unresolved science questions in AGN physics are discussed. Ongoing
low-frequency surveys with the SKA pathfinder telescope GMRT, are highlighted.


title:
Neutron Star Physics in the Square Kilometer Array Era : An Indian
  Perspective

abstract:
  It is an exceptionally opportune time for Astrophysics when a number of
next-generation mega-instruments are poised to observe the universe across the
entire electromagnetic spectrum with unprecedented data quality. The Square
Kilometre Array (SKA) is undoubtedly one of the major components of this
scenario. In particular, the SKA is expected to discover tens of thousands of
new neutron stars giving a major fillip to a wide range of scientific
investigations. India has a sizeable community of scientists working on
different aspects of neutron star physics with immediate access to both the
uGMRT (an SKA pathfinder) and the recently launched X-ray observatory Astrosat.
The current interests of the community largely centre around studies of - a)
the generation of neutron stars and the SNe connection}, b) the neutron star
population and evolutionary pathways}, c) the evolution of neutron stars in
binaries and the magnetic fields}, d) the neutron star equation of state}, e)
the radio pulsar emission mechanism}, and, f) the radio pulsars as probes of
gravitational physics}. Most of these studies are the main goals of the SKA
first phase, which is likely to be operational in the next four years. This
article summarises the science goals of the Indian neutron star community in
the SKA era, with significant focus on coordinated efforts among the SKA and
other existing/upcoming instruments.


title: Probing statistical isotropy of cosmological radio sources using SKA

abstract:
  There currently exist many observations which are not consistent with the
cosmological principle. We review these observations with a particular emphasis
on those relevant for Square Kilometre Array (SKA). In particular, several
different data sets indicate a preferred direction pointing approximately
towards the Virgo cluster. We also observe a hemispherical anisotropy in the
Cosmic Microwave Background Radiation (CMBR) temperature fluctuations. Although
these inconsistencies may be attributed to systematic effects, there remains
the possibility that they indicate new physics and various theories have been
proposed to explain them. One possibility, which we discuss in this review, is
the generation of perturbation modes during the early pre-inflationary epoch,
when the Universe may not obey the cosmological principle. Better measurements
will provide better constraints on these theories. In particular, we propose
measurement of the dipole in number counts, sky brightness, polarized flux and
polarization orientations of radio sources. We also suggest test of alignment
of linear polarizations of sources as a function of their relative separation.
Finally we propose measurement of hemispherical anisotropy or equivalently
dipole modulation in radio sources.


title:
Probing individual sources during reionization and cosmic dawn using SKA
  HI 21-cm observations

abstract:
  Detection of individual luminous sources during the reionization epoch and
cosmic dawn through their signatures in the HI 21-cm signal is one of the
direct approaches to probe the epoch. Here, we summarize our previous works on
this and present preliminary results on the prospects of detecting such sources
using the SKA1-low experiment. We first discuss the expected HI 21-cm signal
around luminous sources at different stages of reionization and cosmic dawn. We
then introduce two visibility based estimators for detecting such signal: one
based on the matched filtering technique and the other relies on simply combing
the visibility signal from different baselines and frequency channels.
  We find that that the SKA1-low should be able to detect ionized bubbles of
radius $R_b \gtrsim 10$ Mpc with $\sim 100$ hr of observations at redshift $z
\sim 8$ provided that the mean outside neutral Hydrogen fraction $ x_{\rm HI}
\gtrsim 0.5$. We also investigate the possibility of detecting HII regions
around known bright QSOs such as around ULASJ1120+0641 discovered by Mortlock
et al. 2011. We find that a $5 \sigma$ detection is possible with $600$ hr of
SKA1-low observations if the QSO age and the outside $ x_{\rm HI} $ are at
least $\sim 2 \times 10^7$ Myr and $\sim 0.2$ respectively.
  Finally, we investigate the possibility of detecting the very first X-ray and
Ly-$\alpha$ sources during the cosmic dawn. We consider mini-QSOs like sources
which emits in X-ray frequency band. We find that with a total $\sim 1000$ hr
of observations, SKA1-low should be able to detect those sources individually
with a $\sim 9 \sigma$ significance at redshift $z=15$. We summarize how the
SNR changes with various parameters related to the source properties.


title:
Explosive and radio-selected Transients: Transient Astronomy with SKA
  and its Precursors

abstract:
  With the high sensitivity and wide-field coverage of the Square Kilometre
Array (SKA), large samples of explosive transients are expected to be
discovered. Radio wavelengths, especially in commensal survey mode, are
particularly well suited for uncovering the complex transient phenomena. This
is because observations at radio wavelengths may suffer less obscuration than
in other bands (e.g. optical/IR or X-rays) due to dust absorption. At the same
time, multiwaveband information often provides critical source classification
rapidly than possible with only radio band data. Therefore, multiwaveband
observational efforts with wide fields of view will be the key to progress of
transients astronomy from the middle 2020s offering unprecedented deep images
and high spatial and spectral resolutions. Radio observations of gamma ray
bursts (GRBs) with SKA will uncover not only much fainter bursts and verifying
claims of sensitivity limited population versus intrinsically dim GRBs, they
will also unravel the enigmatic population of orphan afterglows. The supernova
rate problem caused by dust extinction in optical bands is expected to be
lifted in the SKA era. In addition, the debate of single degenerate scenario
versus double degenerate scenario will be put to rest for the progenitors of
thermonuclear supernovae, since highly sensitive measurements will lead to very
accurate mass loss estimation in these supernovae. One also expects to detect
gravitationally lensed supernovae in far away Universe in the SKA bands. Radio
counterparts of the gravitational waves are likely to become a reality once SKA
comes online. In addition, SKA is likely to discover various new kinds of
transients.


title:
Modelling the 21 cm Signal From the Epoch of Reionization and Cosmic
  Dawn

abstract:
  Studying the cosmic dawn and the epoch of reionization through the redshifted
21 cm line are among the major science goals of the SKA1. Their significance
lies in the fact that they are closely related to the very first stars in the
universe. Interpreting the upcoming data would require detailed modelling of
the relevant physical processes. In this article, we focus on the theoretical
models of reionization that have been worked out by various groups working in
India with the upcoming SKA in mind. These models include purely analytical and
semi-numerical calculations as well as fully numerical radiative transfer
simulations. The predictions of the 21 cm signal from these models would be
useful in constraining the properties of the early galaxies using the SKA data.


title:
Line of sight anisotropies in the Cosmic Dawn and EoR 21-cm power
  spectrum

abstract:
  The line of sight direction in the redshifted 21-cm signal coming from the
cosmic dawn and the epoch of reionization is quite unique in many ways compared
to any other cosmological signal. Different unique effects, such as the
evolution history of the signal, non-linear peculiar velocities of the matter
etc will imprint their signature along the line of sight axis of the observed
signal. One of the major goals of the future SKA-LOW radio interferometer is to
observe the cosmic dawn and the epoch of reionization through this 21-cm
signal. It is thus important to understand how these various effects affect the
signal for it's actual detection and proper interpretation. For more than one
and half decades, various groups in India have been actively trying to
understand and quantify the different line of sight effects that are present in
this signal through analytical models and simulations. In many ways the
importance of this sub-field under 21-cm cosmology have been identified,
highlighted and pushed forward by the Indian community. In this article we
briefly describe their contribution and implication of these effects in the
context of the future surveys of the cosmic dawn and the epoch of reionization
that will be conducted by the SKA-LOW.


title:
The redshifted HI 21 cm signal from the post-reionization epoch:
  Cross-correlations with other cosmological probes

abstract:
  Tomographic intensity mapping of the HI using the redshifted 21 cm
observations opens up a new window towards our understanding of cosmological
background evolution and structure formation. This is a key science goal of
several upcoming radio telescopes including the Square Kilometer Array (SKA).
In this article we focus on the post-reionization signal and investigate the of
cross correlating the 21 cm signal with other tracers of the large scale
structure. We consider the cross-correlation of the post-reionization 21 cm
signal with the Lyman-alpha forest, Lyman-break galaxies and late time
anisotropies in the CMBR maps like weak lensing and the Integrated Sachs Wolfe
effect. We study the feasibility of detecting the signal and explore the
possibility of obtaining constraints on cosmological models using it.


title: Clusters of galaxies and the cosmic web with SKA

abstract:
  The intra-cluster and inter-galactic media (ICM, IGM) that pervade the large
scale structure of the Universe are known to be magnetised at sub-micro Gauss
to micro Gauss levels and to contain cosmic rays (CRs). The acceleration of CRs
and their evolution along with that of magnetic fields in these media is still
not well understood. Diffuse radio sources of synchrotron origin associated
with the ICM such as radio halos, relics and mini-halos are direct probes of
the underlying mechanisms of CR acceleration. Observations with radiotelescopes
such as the GMRT, the VLA and the WSRT (0.15 - 2 GHz) have revealed scaling
relations between the thermal and non-thermal properties of clusters and favour
the role of shocks in the formation of radio relics and of turbulent
re-acceleration in the formation of radio halos and mini-halos. Due to the
limitations of current radio telescopes, wide-band studies and exploration of
low mass and supercluster-scale systems is difficult. The Square Kilometer
Array (SKA) is a next generation radio telescope that will operate in the
frequency range of 0.05 - 20 GHz with unprecedented sensitivities and
resolutions. The expected detection limits of SKA will reveal a few hundred to
thousand new radio halos, relics and mini-halos providing the first large and
comprehensive samples for their study. The wide frequency coverage along with
sensitivity to extended structures will be able to constrain the CR
acceleration mechanisms. The higher frequency (> 5 GHz) observations will be
able to use the Sunyaev-Zel'dovich effect to probe the ICM pressure in addition
to the tracers such as lobes of head-tail radio sources. The SKA also opens
prospects to detect the "off-state" radio emission from the ICM predicted by
the hadronic models and the turbulent re-acceleration models. [abridged]


title: Cosmology and Astrophysics Using the Post-reionization HI

abstract:
  We discuss the prospects of using the redshifted 21~cm emission from neutral
hydrogen in the post-reionization epoch to study our universe. The main aim of
the article is to highlight the efforts of Indian scientists in this area with
the SKA in mind. It turns out that the intensity mapping surveys from SKA can
be instrumental in obtaining tighter constraints on the dark energy models.
Cross-correlation of the HI intensity maps with the Ly$\alpha$ forest data can
also be useful in measuring the BAO scale.


title:
The prospects of measuring the angular power spectrum of the diffuse
  Galactic synchrotron emission with SKA1 Low

abstract:
  The diffuse Galactic synchrotron emission (DGSE) is the most important
diffuse foreground component for future cosmological 21-cm observations. The
DGSE is also an important probe of the cosmic ray electron and magnetic field
distributions in the turbulent interstellar medium (ISM) of our Galaxy. In this
paper we briefly review the Tapered Gridded Estimator (TGE) which can be used
to quantify the angular power spectrum of the sky signal directly from the
visibilities measured in radio-interferometric observations. The salient
features of the TGE are (1.) it deals with the gridded data which makes it
computationally very fast (2.) it avoids a positive noise bias which normally
arises from the system noise inherent to the visibility data, and (3.) it
allows us to taper the sky response and thereby suppresses the contribution
from unsubtracted point sources in the outer parts and the sidelobes of the
antenna beam pattern. We also summarize earlier work where the TGE was used to
measure the C_l of the DGSE using 150 MHz GMRT data. Earlier measurements of
the angular power spectrum are restricted to smaller angular multipole l ~ 10^3
for the DGSE, the signal at the larger l values is dominated by the residual
point sources after source subtraction. The higher sensitivity of the upcoming
SKA1 Low will allow the point sources to be subtracted to a fainter level than
possible with existing telescopes. We predict that it will be possible to
measure the angular power spectrum of the DGSE to larger values of l with SKA1
Low. Our results show that it should be possible to achieve l_{max} ~ 10^4 and
~ 10^5 with 2 minutes and 10 hours of observations respectively.


title:
Interstellar medium and star formation studies with the Square Kilometre
  Array

abstract:
  Stars and planetary systems are formed out of molecular clouds in the
interstellar medium. Although the sequence of steps involved in star formation
are generally known, a comprehensive theory which describes the details of the
processes that drive formation of stars is still missing. The Square Kilometre
Array (SKA), with its unprecedented sensitivity and angular resolution, will
play a major role in filling these gaps in our understanding. In this article,
we present a few science cases that the Indian star formation community is
interested in pursuing with SKA, which include investigation of AU-sized
structures in the neutral ISM, the origin of thermal and non-thermal radio jets
from protostars and the accretion history of protostars, and formation of
massive stars and their effect on the surrounding medium.


title:
Status Report (22th J-PARC PAC): Searching for a Sterile Neutrino at
  J-PARC MLF (E56, JSNS2)

abstract:
  The JSNS$^2$ (J-PARC E56) experiment aims to search for a sterile neutrino at
the J-PARC Materials and Life Sciences Experimental Facility (MLF). After the
submission of a proposal to the J-PARC PAC, Stage-1 approval was granted to the
JSNS$^2$ experiment on April 2015.This approval followed a series of background
measurements which were performed in 2014.
  Recently, funding (the grant-in-aid for scientific research (S)) in Japan for
building one 25~ton fiducial volume detector module was approved for the
experiment. Therefore, we aim to start the experiment with one detector in
JFY2018-2019. We are now working to produce precise cost estimates and schedule
for construction, noting that most of the detector components can be produced
within one year from the date of order. This will be reported at the next PAC
meeting.
  In parallel to the detector construction schedule, JSNS$^2$ will submit a
Technical Design report (TDR) to obtain the Stage-2 approval from the J-PARC
PAC.The recent progress of the R$\&$D efforts towards this TDR are shown in
this report. In particular, the R$\&$D status of the liquid scintillator,
cosmic ray veto system, and software are shown.
  We have performed a test-experiment using 1.6~L of liquid scintillator at the
3rd floor of the MLF building in order to determine the identities of
non-neutrino background particles coming to this detector location during the
proton bunch. This is the so-called "MLF 2015AU0001" experiment. We briefly
show preliminary results from this test-experiment.


title: Mesoscale circulation along the Sakhalin Island eastern coast

abstract:
  The seasonal and interannual variability of mesoscale circulation along the
eastern coast of the Sakhalin Island in the Okhotsk Sea is investigated using
AVISO velocity field and oceanographic data for the period from 1993 to 2016.
It is found that mesoscale cyclones with the horizontal dimension of about 100
km occur there predominantly during summer, whereas anticyclones occur
predominantly during fall and winter. The cyclones are generated due to the
coastal upwelling forced by northward winds and the positive wind stress curl
along the Sakhalin coast. The anticyclones are formed due to an inflow of
low-salinity Amur-River waters from the Sakhalin Gulf intensified by southward
winds and the negative wind stress curl in the cold season. The mesoscale
cyclones support the high biological productivity at the eastern Sakhalin shelf
in July - August.


title:
Effects of the Lorentz invariance violation in Coulomb interaction in
  nuclei and atoms

abstract:
  Anisotropy in the speed of light that has been constrained by
Michelson-Morley-type experiments also generates anisotropy in the Coulomb
interactions. This anisotropy can manifest itself as an energy anisotropy in
nuclear and atomic experiments. Here the experimental limits on Lorentz
violation in 21Ne are used to improve the limits on the Lorentz symmetry in the
photon sector, namely the anisotropy of the speed of light and the Coulomb
interactions, by 7 orders of magnitude in comparison with previous experiments:
the speed of light is isotropic to a part in E-28.


title:
Tensor Decompositions for Identifying Directed Graph Topologies and
  Tracking Dynamic Networks

abstract:
  Directed networks are pervasive both in nature and engineered systems, often
underlying the complex behavior observed in biological systems, microblogs and
social interactions over the web, as well as global financial markets. Since
their structures are often unobservable, in order to facilitate network
analytics, one generally resorts to approaches capitalizing on measurable nodal
processes to infer the unknown topology. Structural equation models (SEMs) are
capable of incorporating exogenous inputs to resolve inherent directional
ambiguities. However, conventional SEMs assume full knowledge of exogenous
inputs, which may not be readily available in some practical settings. The
present paper advocates a novel SEM-based topology inference approach that
entails factorization of a three-way tensor, constructed from the observed
nodal data, using the well-known parallel factor (PARAFAC) decomposition. It
turns out that second-order piecewise stationary statistics of exogenous
variables suffice to identify the hidden topology. Capitalizing on the
uniqueness properties inherent to high-order tensor factorizations, it is shown
that topology identification is possible under reasonably mild conditions. In
addition, to facilitate real-time operation and inference of time-varying
networks, an adaptive (PARAFAC) tensor decomposition scheme which tracks the
topology-revealing tensor factors is developed. Extensive tests on simulated
and real stock quote data demonstrate the merits of the novel tensor-based
approach.


title: Manifolds tightly covered by two metric balls

abstract:
  In this note we provide natural optimal geometric conditions for a Riemannian
manifold suitably covered by two open metric balls to be homeomorphic to a
sphere. This can be viewed as a geometric analogue of Brown's theorem in
topology stating that a closed manifold covered by two topological balls is a
sphere.


title: Cohomology rings, differential graded algebras and derived equivalences

abstract:
  In this paper, we will consider derived equivalences for differential graded
endomorphism algebras by Keller's approaches. First we construct derived
equivalences of differential graded algebras which are endomorphism algebras of
the objects from a triangle in the homotopy category of differential graded
algebras. We also obtain derived equivalences of differential graded
endomorphism algebras from a standard derived equivalence of finite dimensional
algebras. Moreover, under some conditions, the cohomology rings of these
differential graded endomorphism algebras are also derived equivalent. Then we
give an affirmative answer to a problem of Dugas \cite{Dugas2015} in some
special case.


title:
Transfer entropy in continuous time, with applications to jump and
  neural spiking processes

abstract:
  Transfer entropy has been used to quantify the directed flow of information
between source and target variables in many complex systems. While transfer
entropy was originally formulated in discrete time, in this paper we provide a
framework for considering transfer entropy in continuous time systems, based on
Radon-Nikodym derivatives between measures of complete path realizations. To
describe the information dynamics of individual path realizations, we introduce
the pathwise transfer entropy, the expectation of which is the transfer entropy
accumulated over a finite time interval. We demonstrate that this formalism
permits an instantaneous transfer entropy rate. These properties are analogous
to the behavior of physical quantities defined along paths such as work and
heat. We use this approach to produce an explicit form for the transfer entropy
for pure jump processes, and highlight the simplified form in the specific case
of point processes (frequently used in neuroscience to model neural spike
trains). Finally, we present two synthetic spiking neuron model examples to
exhibit the pertinent features of our formalism, namely, that the information
flow for point processes consists of discontinuous jump contributions (at
spikes in the target) interrupting a continuously varying contribution
(relating to waiting times between target spikes). Numerical schemes based on
our formalism promise significant benefits over existing strategies based on
discrete time formalisms.

categories: cs.IT math.IT nlin.AO physics.data-an q-bio.NC


title:
Multi-Antenna Transmission in Downlink Heterogeneous Cellular Networks
  under A Threshold-based Mobile Association Policy

abstract:
  With the recent emergence of 5G era, heterogeneous cellular networks (HCNs)
have invoked a popular research interest. In this paper, we provide a
comprehensive analysis for multiantenna transmissions in a multi-tier downlink
HCN. We first propose a reliability-oriented threshold-based mobile association
policy, where each user connects to the strongest base station from which this
user can obtain the largest truncated long-term received power. Under our
mobile association policy, we derive analytical expressions for the exact
outage probability of an arbitrary randomly located user, along with
computationally convenient lower and upper bounds. Asymptotic analysis on the
outage probability shows that introducing a large access threshold into mobile
association significantly decreases the outage probability. We further
investigate the spectrum efficiency and the energy efficiency of the HCN. Our
theoretic analysis and numerical validations show that both the spectrum and
energy efficiencies can be improved by properly choosing the access threshold.


title:
Observation of the supersolid stripe phase in spin-orbit coupled
  Bose-Einstein condensates

abstract:
  Supersolidity is an intriguing concept. It combines the property of
superfluid flow with the long-range spatial periodicity of solids, two
properties which are often mutually exclusive. The original discussion of
quantum crystals and supersolidity focuses on solid Helium-4 where it was
predicted that vacancies could form dilute weakly interacting Bose-Einstein
condensates. In this system, direct observation of supersolidity has been
elusive. The concept of supersolidity was then generalized to include other
superfluid systems which break the translational symmetry of space. One of such
systems is a Bose-Einstein condensate with spin-orbit coupling which has a
supersolid stripe phase. Despite several recent studies of this system, the
stripe phase has not been observed. Here we report the direct observation of
the predicted density modulation of the stripe phase using Bragg reflection.
Our work establishes a system with unique symmetry breaking properties. Of
future interest is further spatial symmetry breaking through the introduction
of vortices, solitons, impurities or disorder.


title:
On stochastic mirror-prox algorithms for stochastic Cartesian
  variational inequalities: randomized block coordinate and optimal averaging
  schemes

abstract:
  Motivated by multi-user optimization problems and non-cooperative Nash games
in uncertain regimes, we consider stochastic Cartesian variational inequalities
(SCVI) where the set is given as the Cartesian product of a collection of
component sets. First, we consider the case where the number of the component
sets is large. For solving this type of problems, the classical stochastic
approximation methods and their prox generalizations are computationally
inefficient as each iteration becomes very costly. To address this challenge,
we develop a randomized block stochastic mirror-prox (B-SMP) algorithm, where
at each iteration only a randomly selected block coordinate of the solution is
updated through implementing two consecutive projection steps. Under standard
assumptions on the problem and settings of the algorithm, we show that when the
mapping is strictly pseudo-monotone, the algorithm generates a sequence of
iterates that converges to the solution of the problem almost surely. To derive
rate statements, we assume that the maps are strongly pseudo-monotone and
obtain {a non-asymptotic mean squared error
$\mathcal{O}\left(\frac{d}{k}\right)$, where $k$ is the iteration number and
$d$ is the number of component sets. Second, we consider large-scale stochastic
optimization problems with convex objectives. For this class of problems, we
develop a new averaging scheme for the B-SMP algorithm. Unlike the classical
averaging stochastic mirror-prox (SMP) method where a decreasing set of weights
for the averaging sequence is used, here we consider a different set of weights
that are characterized in terms of the stepsizes and a {parameter}. We show
that using such weights, the objective values of the averaged sequence
converges to the optimal value in the mean sense with the rate
$\mathcal{O}\left(\frac{\sqrt{d}}{\sqrt{k}}\right)$.


title: What tell us LHC data about Higgs boson parity

abstract:
  Recently CMS and ATLAS announced that they had measured the Higgs boson
parity. Here we note that their approach can determine this parity only under
the additional assumption that this particle has a definite parity.
  If parity conservation is violated in the Higgs sector, the parity of
observed "Higgs" boson does not exist. The approach used in the mentioned
experiments does not allow to observe such opportunity. In this sense titles of
mentioned CMS and ATLAS publications are misleading.


title:
On the domain of fractional Laplacians and related generators of Feller
  processes

abstract:
  In this paper we study the domain of stable processes, stable-like processes
and more general pseudo- and integro-differential operators which naturally
arise both in analysis and as infinitesimal generators of L\'evy- and
L\'evy-type (Feller) processes. In particular we obtain conditions on the
symbol of the operator ensuring that certain (variable order) H\"{o}lder and
H\"{o}lder-Zygmund spaces are in the domain. We use tools from probability
theory to investigate the small-time asymptotics of the generalized moments of
a L\'evy or L\'evy-type process $(X_t)_{t \geq 0}$, \begin{equation*}
  \lim_{t \to 0} \frac 1t\left(\mathbb{E}^x f(X_t)-f(x)\right), \quad
x\in\mathbb{R}^d, \end{equation*} for functions $f$ which are not necessarily
bounded or differentiable. The pointwise limit exists for fixed $x \in
\mathbb{R}^d$ if $f$ satisfies a H\"{o}lder condition at $x$. Moreover, we give
sufficient conditions which ensure that the limit exists uniformly in the space
of continuous functions vanishing at infinity. As an application we prove that
the domain of the generator of $(X_t)_{t \geq 0}$ contains certain H\"{o}lder
spaces of variable order. Our results apply, in particular, to stable-like
processes, relativistic stable-like processes, solutions of L\'evy-driven SDEs
and L\'evy processes.


title: Static Analysis Using the Cloud

abstract:
  In this paper we describe our experience of using Microsoft Azure cloud
computing platform for static analysis. We start by extending Static Driver
Verifier to operate in the Microsoft Azure cloud with significant improvements
in performance and scalability. We present our results of using SDV on single
drivers and driver suites using various configurations of the cloud relative to
a local machine. Finally, we describe the Static Module Verifier platform, a
highly extensible and configurable platform for static analysis of generic
modules, where we have integrated support for verification using a cloud
services provider (Microsoft Azure in this case).


title: Modeling Deployment Decisions for Elastic Services with ABS

abstract:
  The use of cloud technology can offer significant savings for the deployment
of services, provided that the service is able to make efficient use of the
available virtual resources to meet service-level requirements. To avoid
software designs that scale poorly, it is important to make deployment
decisions for the service at design time, early in the development of the
service itself. ABS offers a formal, model-based approach which integrates the
design of services with the modeling of deployment decisions. In this paper, we
illustrate the main concepts of this approach by modeling a scalable pool of
workers with an auto-scaling strategy and by using the model to compare
deployment decisions with respect to client traffic with peak loads.


title: Configuring Cloud-Service Interfaces Using Flow Inheritance

abstract:
  Technologies for composition of loosely-coupled web services in a modular and
flexible way are in high demand today. On the one hand, the services must be
flexible enough to be reused in a variety of contexts. On the other hand, they
must be specific enough so that their composition may be provably consistent.
The existing technologies (WS-CDL, WSCI and session types) require a
behavioural contract associated with each service, which is impossible to
derive automatically. Furthermore, neither technology supports flow
inheritance: a mechanism that automatically and transparently propagates data
through service pipelines. This paper presents a novel mechanism for automatic
interface configuration of such services. Instead of checking consistency of
the behavioural contracts, our approach focuses solely on that of data formats
in the presence of subtyping, polymorphism and flow inheritance. The paper
presents a toolchain that automatically derives service interfaces from the
code and performs interface configuration taking non-local constraints into
account. Although the configuration mechanism is global, the services are
compiled separately. As a result, the mechanism does not raise source security
issues despite global service availability in adaptable form.


title: An Enhanced Model for Stochastic Coordination

abstract:
  Applications developed over the cloud coordinate several, often anonymous,
computational resources, distributed over different execution nodes, within
flexible architectures. Coordination models able to represent quantitative data
provide a powerful basis for their analysis and validation. This paper extends
IMCreo, a semantic model for Stochastic reo based on interactive Markov chains,
to enhance its scalability, by regarding each channel and node, as well as
interface components, as independent stochastic processes that may (or may not)
synchronise with the rest of the coordination circuit.


title:
Hadronic production of $D(2550)$, $D^*(2600)$, $D(2750)$, $D^*_1(2760)$
  and $D^*_3(2760)$

abstract:
  Hadronic decays of radially excited $2D$ $D(2^3D_1)$, $D(2^3D_3)$, $D(2D_2)$
and $D(2D^\prime_2)$ have been studied in a $^3P_0$ model. All OZI-allowed
decay channels of these $2D$ $D$ resonances have been given, and relevant decay
widths have been calculated. $D(2550)$, $D^*(2600)$, $D(2750)$, $D^*_1(2760)$
and $D^*_3(2760)$ can be produced in hadronic decays of $D(2^3D_1)$,
$D(2^3D_3)$, $D(2D_2)$ and $D(2D^\prime_2)$. In different assignments, hadronic
decay widths and some relevant ratios from the $2D$ $D$ resonances to
$D(2550)$, $D^*(2600)$, $D(2750)$, $D^*_1(2760)$ or $D^*_3(2760)$ final states
have been predicted, which may provide some more information to identify these
resonances in forthcoming experiments.


title:
Arbres CART et For\^ets al\'eatoires, Importance et s\'election de
  variables

abstract:
  Two algorithms proposed by Leo Breiman : CART trees (Classification And
Regression Trees for) introduced in the first half of the 80s and random
forests emerged, meanwhile, in the early 2000s, are the subject of this
article. The goal is to provide each of the topics, a presentation, a
theoretical guarantee, an example and some variants and extensions. After a
preamble, introduction recalls objectives of classification and regression
problems before retracing some predecessors of the Random Forests. Then, a
section is devoted to CART trees then random forests are presented. Then, a
variable selection procedure based on permutation variable importance is
proposed. Finally the adaptation of random forests to the Big Data context is
sketched.


title: Percolative properties of Brownian interlacements and its vacant set

abstract:
  In this article we investigate the percolative properties of Brownian
interlacements, a model introduced by Alain-Sol Sznitman in arXiv:1209.4531,
and show that: the interlacement set is "well-connected", i.e., any two
"sausages" in $d$-dimensional Brownian interlacements, $d\geq 3$, can be
connected via no more than $\lceil (d-4)/2 \rceil$ intermediate sausages almost
surely; while the vacant set undergoes a non-trivial percolation phase
transition when the level parameter varies.


title:
Wall modeling via function enrichment within a high-order DG method for
  RANS simulations of incompressible flow

abstract:
  We present a novel approach to wall modeling for RANS within the
discontinuous Galerkin method. Wall functions are not used to prescribe
boundary conditions as usual but they are built into the function space of the
numerical method as a local enrichment, in addition to the standard polynomial
component. The Galerkin method then automatically finds the optimal solution
among all shape functions available. This idea is fully consistent and gives
the wall model vast flexibility in separated boundary layers or high adverse
pressure gradients. The wall model is implemented in a high-order discontinuous
Galerkin solver for incompressible flow complemented by the Spalart-Allmaras
closure model. As benchmark examples we present turbulent channel flow starting
from $Re_{\tau}=180$ and up to $Re_{\tau}=100{,}000$ as well as flow past
periodic hills at Reynolds numbers based on the hill height of $Re_H=10{,}595$
and $Re_{H}=19{,}000$.

categories: physics.flu-dyn math.NA physics.ao-ph physics.comp-ph


title: The reversible negacyclic codes over finite fields

abstract:
  In this paper, by investigating the factor of the $x^n+1$, we deduce that the
structure of the reversible negacyclic code over the finite field
$\mathbb{F}_{q}$, where $q$ is an odd prime power. Though studying
$q-$cyclotomic cosets modulo $2n$, we obtain the parameters of negacyclic BCH
code of length $n=\frac{q^\ell+1}{2}$ , $n=\frac{q^m-1}{2(q-1)}$ and
$n=\frac{q^{t\cdot2^\tau}-1}{2(q^t+1)}$. Some optimal linear codes from
negacyclic codes are given. Finally, we discuss a class of MDS LCD negacyclic
codes.


title:
Finite size effects and equilibration in Bose-Hubbard chains with
  central well dephasing

abstract:
  We investigate Bose-Hubbard chains in a central depleted well configuration,
with dephasing in the middle well. We look at equilibration of populations,
pseudo-entropy, and entanglement measures. Using stochastic integration in the
truncated Wigner representation, we find that the initial quantum states of the
occupied wells has an influence on the subsequent dynamics, and that with more
than three wells, the chains do not reach a full equilibrium, with edge effects
becoming important, and the time to reach the steady state becoming longer. The
evolutions with and without phase diffusion are qualitatively different. We
find no convincing evidence of entanglement in the final states with phase
diffusion. Although at least one accepted measure indicates the presence of
mode entanglement, we are easily able to show that it can give ambiguous
predictions.


title: New area-minimizing Lawson-Osserman cones

abstract:
  It has been 40 years since Lawson and Osserman introduced the three minimal
cones associated with Dirichlet problems in their 1977 Acta paper [LO77]. The
first cone was shown area-minimizing by Harvey and Lawson in the celebrated
paper [HL82]. In this paper, we confirm that the other two are also
area-minimizing. In fact, we show that every Lawson-Osserman cone of type (n,
p, 2) constructed in [XYZ] is area-minimizing.


title: Contracting convex hypersurfaces by functions of the mean curvature

abstract:
  This paper concerns the evolution of a closed convex hypersurface in
${\mathbb{R}}^{n+1}$, in direction of its inner unit normal vector, where the
speed is given by a smooth function depending only on the mean curvature, and
satisfies some further restrictions, without requiring homogeneity. It is shown
that the flow exists on a finite maximal interval, convexity is preserved and
the hypersurfaces shrink down to a single point as the final time is
approached. This result covers and generalises the corresponding result of
Schulze \cite{Sch05} for the positive power mean curvature flow to a much
larger possible class of flows by the functions depending only on the mean
curvature.


title: Price of Transparency in Strategic Machine Learning

abstract:
  Based on the observation that the transparency of an algorithm comes with a
cost for the algorithm designer when the users (data providers) are strategic,
this paper studies the impact of strategic intent of the users on the design
and performance of transparent ML algorithms. We quantitatively study the {\bf
price of transparency} in the context of strategic classification algorithms,
by modeling the problem as a nonzero-sum game between the users and the
algorithm designer. The cost of having a transparent algorithm is measured by a
quantity, named here as price of transparency which is the ratio of the
designer cost at the Stackelberg equilibrium, when the algorithm is transparent
(which allows users to be strategic) to that of the setting where the algorithm
is not transparent.


title: Multidimensional linearizable system of $n$-wave type equations

abstract:
  A linearizable version of multidimensional system of $n$-wave type nonlinear
PDEs is proposed. This system is derived using the spectral representation of
its solution via the procedure similar to the dressing method for the
ISTM-integrable nonlinear PDEs. The proposed system is shown to be completely
integrable, particular solution is represented.


title: Coset construction of AdS particle dynamics

abstract:
  We analyze dynamics of the AdS$_{N+1}$ particle realized on the coset
SO$(2,N)/$SO$(1,N)$. Hamiltonian reduction provides the physical phase space in
terms of the coadjoint orbit obtained by boosting a timelike element of ${\frak
so}(2,N)$. We show equivalence of this approach to geometric quantization and
to the SO$(N)$ covariant oscillator description, for which the boost generators
entail a complicated operator ordering. As an alternative scheme, we introduce
dual oscillator variables and derive their algebra at the classical and the
quantum level. This simplifies the calculations of the commutators for the
boost generators and leads to unitary irreducible representations of ${\frak
so}(2,N)$ for all admissible values of the mass parameter. We furthermore
discuss an SO$(N)$ covariant supersymmetric extensions of the oscillator
quantization, with its realization for superparticles in AdS$_2$ and AdS$_3$
given by recent works.


title:
Quantum correlations responsible for remote state creation: strong and
  weak control parameters

abstract:
  We study the quantum correlations between the two remote qubits (sender and
receiver) connected by the transmission line (homogeneous spin-1/2 chain)
depending on the parameters of the sender's and receiver's initial states
(control parameters).
  We consider two different measures of quantum correlations: the entanglement
(a traditional measure) and the informational correlation (based on the
parameter exchange between the sender and receiver).
  We find the domain in the control parameter space yielding (i) zero
entanglement between the sender and receiver during the whole evolution period
and (ii) non-vanishing informational correlation between the sender and
receiver, thus showing that the informational correlation is responsible for
the remote state creation. Among the control parameters, there are the strong
parameters (which strongly effect the values of studied measures) and the weak
ones (whose effect is negligible), therewith the eigenvalues of the initial
state are given a privileged role. We also show that the problem of small
entanglement (concurrence) in quantum information processing is similar (in
certain sense) to the problem of small determinants in linear algebra. A
particular model of 40-node spin-1/2 communication line is presented.


title:
Mixed volume preserving flow by powers of homogeneous curvature
  functions of degree one

abstract:
  This paper concerns the evolution of a closed hypersurface of dimension
$n(\geq 2)$ in the Euclidean space ${\mathbb{R}}^{n+1}$ under a mixed volume
preserving flow. The speed equals a power $\beta (\geq 1)$ of homogeneous,
either convex or concave, curvature functions of degree one plus a mixed volume
preserving term, including the case of powers of the mean curvature and of the
Gauss curvature. The main result is that if the initial hypersurface satisfies
a suitable pinching condition, there exists a unique, smooth solution of the
flow for all times, and the evolving hypersurfaces converge exponentially to a
round sphere, enclosing the same mixed volume as the initial hypersurface. This
result covers and generalises the previous results for convex hypersurfaces in
the Euclidean space by McCoy \cite{McC05} and Cabezas-Rivas and Sinestrari
\cite{CS10} to more general curvature flows for convex hypersurfaces with
similar curvature pinching condition.


title:
Spontaneous structural distortion of metallic Shastry-Sutherland system
  DyB4 by quadrupole-spin-lattice coupling

abstract:
  DyB4 has a two-dimensional Shastry-Sutherland (Sh-S) lattice with strong
Ising character of the Dy ions. Despite the intrinsic frustrations,
surprisingly, it undergoes two successive transitions: a magnetic ordering at
TN = 20K, and a quadrupole ordering at TQ=12.5 K. From high-resolution neutron
and synchrotron X-ray powder diffraction studies, we have obtained full
structural information on this material in all phases, and demonstrate that
structural modifications occurring at quadrupolar transition lead to the
lifting of frustrations inherent in the Sh-S model. Our study thus provides a
complete experimental picture of how the intrinsic frustration of the Sh-S
lattice can be lifted by the coupling to quadrupole moments. We show that two
other factors, i.e. strong spin-orbit coupling and long-range RKKY interaction
in metallic DyB4, play an important role in this behavior.


title:
Huddler: Convening Stable and Familiar Crowd Teams Despite Unpredictable
  Availability

abstract:
  Distributed, parallel crowd workers can accomplish simple tasks through
workflows, but teams of collaborating crowd workers are necessary for complex
goals. Unfortunately, a fundamental condition for effective teams - familiarity
with other members - stands in contrast to crowd work's flexible, on-demand
nature. We enable effective crowd teams with Huddler, a system for workers to
assemble familiar teams even under unpredictable availability and strict time
constraints. Huddler utilizes a dynamic programming algorithm to optimize for
highly familiar teammates when individual availability is unknown. We first
present a field experiment that demonstrates the value of familiarity for crowd
teams: familiar crowd teams doubled the performance of ad-hoc (unfamiliar)
teams on a collaborative task. We then report a two-week field deployment
wherein Huddler enabled crowd workers to convene highly familiar teams in 18
minutes on average. This research advances the goal of supporting long-term,
team-based collaborations without sacrificing the flexibility of crowd work.


title:
Assessing Percolation Threshold Based on High-Order Non-Backtracking
  Matrices

abstract:
  Percolation threshold of a network is the critical value such that when nodes
or edges are randomly selected with probability below the value, the network is
fragmented but when the probability is above the value, a giant component
connecting large portion of the network would emerge. Assessing the percolation
threshold of networks has wide applications in network reliability, information
spread, epidemic control, etc. The theoretical approach so far to assess the
percolation threshold is mainly based on spectral radius of adjacency matrix or
non-backtracking matrix, which is limited to dense graphs or locally treelike
graphs, and is less effective for sparse networks with non-negligible amount of
triangles and loops. In this paper, we study high-order non-backtracking
matrices and their application to assessing percolation threshold. We first
define high-order non-backtracking matrices and study the properties of their
spectral radii. Then we focus on 2nd-order non-backtracking matrix and
demonstrate analytically that the reciprocal of its spectral radius gives a
tighter lower bound than those of adjacency and standard non-backtracking
matrices. We further build a smaller size matrix with the same largest
eigenvalue as the 2nd-order non-backtracking matrix to improve computation
efficiency. Finally, we use both synthetic networks and 42 real networks to
illustrate that the use of 2nd-order non-backtracking matrix does give better
lower bound for assessing percolation threshold than adjacency and standard
non-backtracking matrices.


title:
Resistive Switching and Voltage Induced Modulation of Tunneling
  Magnetoresistance in Nanosized Perpendicular Organic Spin Valves

abstract:
  Nanoscale multifunctional perpendicular organic spin valves have been
fabricated. The devices based on an La$_{0.7}$Sr$_{0.3}$MnO$_3$/Alq$_3$/Co
trilayer show resistive switching of up to 4-5 orders of magnitude and
magnetoresistance as high as -70% the latter even changing sign when voltage
pulses are applied. This combination of phenomena is typically observed in
multiferroic tunnel junctions where it is attributed to magnetoelectric
coupling between a ferromagnet and a ferroelectric material. Modeling indicates
that here the switching originates from a modification of the
La$_{0.7}$Sr$_{0.3}$MnO$_3$ surface. This modification influences the tunneling
of charge carriers and thus both the electrical resistance and the tunneling
magnetoresistance which occurs at pinholes in the organic layer.


title:
On large deviations for Gibbs measures, mean energy and
  Gamma-convergence

abstract:
  We consider the random point processes on a measure space X defined by the
Gibbs measures associated to a given sequence of N-particle Hamiltonians
H^{(N)}. Inspired by the method of Messer-Spohn for proving concentration
properties for the laws of the corresponding empirical measures, we propose a
number of hypotheses on H^{(N)} which are quite general, but still strong
enough to extend the approach of Messer-Spohn. The hypotheses are formulated in
terms of the asymptotics of the corresponding mean energy functionals. We show
that in many situations the approach even yields a Large Deviation Principle
(LDP) for the corresponding laws. Connections to Gamma-convergence of (free)
energy type functionals at different levels are also explored. The focus is on
differences between positive and negative temperature situations, motivated by
applications to complex geometry. The results yield, in particular, large
deviation principles at positive as well as negative temperatures for quite
general classes of singular mean field models with pair interactions,
generalizing the 2D vortex model and Coulomb gases. In a companion paper the
results are illustrated in the setting of Coulomb and Riesz type gases on a
Riemannian manifold X, comparing with the complex geometric setting.