title: The concept of quasi-integrability

abstract:
  We show that certain field theory models, although non-integrable according
to the usual definition of integrability, share some of the features of
integrable theories for certain configurations. Here we discuss our attempt to
define a "quasi-integrable theory", through a concrete example: a deformation
of the (integrable) sine-Gordon potential. The techniques used to describe and
define this concept are both analytical and numerical. The zero-curvature
representation and the abelianisation procedure commonly used in integrable
field theories are adapted to this new case and we show that they produce
asymptotically conserved charges that can then be observed in the simulations
of scattering of solitons.


title: LHC Phenomenology of SO(10) Models with Yukawa Unification

abstract:
  In this paper we study an SO(10) SUSY GUT with Yukawa unification for the
third generation. We perform a global chi^2 analysis given to obtain the GUT
boundary conditions consistent with 11 low energy observables, including the
top, bottom and tau masses. We assume a universal mass, m_{16}, for squarks and
sleptons and a universal gaugino mass, M_{1/2}. We then analyze the
phenomenological consequences for the LHC for 15 benchmark models with fixed
m_{16} = 20 TeV and with varying values of the gluino mass. The goal of the
present work is to (i) evaluate the lower bound on the gluino mass in our model
coming from the most recent published data of CMS and (ii) to compare this
bound with similar bounds obtained by CMS using simplified models. The bottom
line is that the bounds coming from the same sign di-lepton analysis are
comparable for our model and the simplified model studied assuming BR(gluino ->
t tbar neutralino) = 100%. However the bounds coming from the purely hadronic
analyses for our model are 10 - 20% lower than obtained for the simplified
models. This is due to the fact that for our models the branching ratio for the
decay gluino -> g neutralino is significant. Thus there are significantly fewer
b-jets. We find a lower bound on the gluino mass in our models with M_{gluino}
> 1000 GeV. Finally, there is a theoretical upper bound on the gluino mass
which increases with the value of m_{16}. For m_{16} <= 30 TeV, the gluino mass
satisfies M_{gluino} <= 2.8 TeV at 90% CL. Thus, unless we further increase the
amount of fine-tuning, we expect gluinos to be discovered at LHC 14.


title: Superspace conformal field theory

abstract:
  Conformal sigma models and WZW models on coset superspaces provide important
examples of logarithmic conformal field theories. They possess many
applications to problems in string and condensed matter theory. We review
recent results and developments, including the general construction of WZW
models on type I supergroups, the classification of conformal sigma models and
their embedding into string theory.


title:
Mean-field theory of baryonic matter for QCD in the large $N_{c}$ and
  heavy quark mass limits

abstract:
  We discuss theoretical issues pertaining to baryonic matter in the combined
heavy-quark and large $N_c$ limits of QCD. Witten's classic argument that
baryons and interacting systems of baryons can be described in a mean-field
approximation with each of the quarks moving in an average potential due to the
remaining quarks is heuristic. It is important to justify this heuristic
description for the case of baryonic matter since systems of interacting
baryons are intrinsically more complicated than single baryons due to the
possibility of hidden color states---states in which the subsystems making up
the entire baryon crystal are not color-singlet nucleons but rather colorful
states coupled together to make a color-singlet state. In this work, we provide
a formal justification of this heuristic prescription. In order to do this, we
start by taking the heavy quark limit, thus effectively reducing the problem to
a many-body quantum mechanical system. This problem can be formulated in terms
of integrals over coherent states, which for this problem are simple Slater
determinants. We show that for the many-body problem, the support region for
these integrals becomes narrow at large $N_c$, yielding an energy which is
well-approximated by a single coherent state---that is a mean-field
description. Corrections to the energy are of relative order $1/N_c$. While
hidden color states are present in the exact state of the heavy quark system,
they only influence the interaction energy at sub-leading order in $1/N_{c}$.


title:
Tensor network trial states for chiral topological phases in two
  dimensions and a no-go theorem in any dimension

abstract:
  Trial wavefunctions that can be represented by summing over locally-coupled
degrees of freedom are called tensor network states (TNSs); they have seemed
difficult to construct for two-dimensional topological phases that possess
protected gapless edge excitations. We show it can be done for chiral states of
free fermions, using a Gaussian Grassmann integral, yielding $p_x \pm i p_y$
and Chern insulator states, in the sense that the fermionic excitations live in
a topologically non-trivial bundle of the required type. We prove that any
strictly short-range quadratic parent Hamiltonian for these states is gapless;
the proof holds for a class of systems in any dimension of space. The proof
also shows, quite generally, that sets of compactly-supported Wannier-type
functions do not exist for band structures in this class. We construct further
examples of TNSs that are analogs of fractional (including non-Abelian) quantum
Hall phases; it is not known whether parent Hamiltonians for these are also
gapless.

categories: cond-mat.mes-hall cond-mat.str-el hep-th quant-ph


title: Search for VHE Gamma-Ray Emission from Young SNe with H.E.S.S

abstract:
  Supernova (SN) remnants are a well motivated candidate for the acceleration
sites of cosmic rays with energies up to the knee (10^15 eV). It has been
suggested that also young SNe (~<1 year after the explosion) may be able to
accelerate cosmic rays to even higher energies. A smoking gun for cosmic-ray
acceleration in young SNe would be the production of very-high-energy (VHE, >10
GeV) gamma-ray radiation. The H.E.S.S. imaging air Cherenkov telescope array is
an instrument sensitive to such radiation. In this contribution, the pointing
directions of the H.E.S.S. telescopes are compared to a recently published,
extragalactic SN catalogue to identify coincidental observations. The results
of the data analysis are discussed.


title: Supercritical instability in graphene with two charged impurities

abstract:
  We study the supercritical instability in gapped graphene with two charged
impurities separated by distance R using the two-dimensional Dirac equation for
electron quasiparticles. Attention is paid to a situation when charges of
impurities are subcritical, whereas their total charge exceeds a critical one.
The critical distance R_{cr} in the system of two charged centers is defined as
that at which the electron bound state with the lowest energy reaches the
boundary of the lower continuum. A variational calculation of the critical
distance R_{cr} separating the supercritical (R<R_{cr}) and subcritical
(R>R_{cr}) regimes is carried out. It is shown that the critical distance
R_{cr} increases as the quasiparticle gap decreases. The energy and width of a
quasistationary state as functions of the distance between two impurities are
derived in the quasiclassical approximation.

categories: cond-mat.mes-hall cond-mat.str-el hep-ph nucl-th


title: Spectral methods for network community detection and graph partitioning

abstract:
  We consider three distinct and well studied problems concerning network
structure: community detection by modularity maximization, community detection
by statistical inference, and normalized-cut graph partitioning. Each of these
problems can be tackled using spectral algorithms that make use of the
eigenvectors of matrix representations of the network. We show that with
certain choices of the free parameters appearing in these spectral algorithms
the algorithms for all three problems are, in fact, identical, and hence that,
at least within the spectral approximations used here, there is no difference
between the modularity- and inference-based community detection methods, or
between either and graph partitioning.

categories: physics.soc-ph cond-mat.stat-mech cs.SI physics.data-an


title:
A Super-Eddington Wind Scenario for the Progenitors of Type Ia
  Supernovae

abstract:
  The accretion of hydrogen-rich material onto carbon-oxygen white dwarfs (CO
WDs) is crucial for understanding type Ia supernova (SN Ia) from the
single-degenerate model, but this process has not been well understood due to
the numerical difficulties in treating H and He flashes during the accretion.
For the CO WD masses from 0.5 to $1.378\,{M}_\odot$ and accretion rates in the
range from $10^{-8}$ to $10^{-5}\,{M}_\odot\,\mbox{yr}^{-1}$, we simulated the
accretion of solar-composition material onto CO WDs using the state-of-the-art
stellar evolution code of {\sc MESA}. For comparison with the steady-state
models (e.g \citet{nskh07}), we firstly ignored the contribution from nuclear
burning to the luminosity when determining the Eddington accretion rate and
found that the properties of H burning in our accreting CO WD models are
similar to those from the steady-state models, except that the critical
accretion rates at which the WDs turn into red giants or H-shell flashes occur
on their surfaces are slightly higher than those from the steady-state models.
However, the super-Eddington wind is triggered at much lower accretion rates,
than previously thought, when the contribution of nuclear burning to the total
luminosity is included. This super-Eddington wind naturally prevents the CO WDs
with high accretion rates from becoming red giants, thus presenting an
alternative to the optically thick wind proposed by \cite{hkn96}. Furthermore,
the super-Eddington wind works in low-metallicity environments, which may
explain SNe Ia observed at high redshifts.


title:
Generalized spin-wave theory: application to the bilinear-biquadratic
  model

abstract:
  We present a generalized spin-wave theory (GSWT) for treating spin
Hamiltonians of arbitrary spin $S$. The generalization consists of an extension
of the traditional spin-wave theory from SU(2) to SU($N$). Low energy
excitations are waves of the local order parameter that fluctuates in the
SU($N$) space of unitary transformations of the local spin states, instead of
the SU(2) space of local spin rotations. Since the generators of the SU($N$)
group can be represented as bilinear forms in $N$-flavored bosons, the
low-energy modes of the GSWT are described with $N-1$ different bosons. The
generalization allows treating quantum spin systems whose ground state exhibit
multipolar ordering as well as detecting instabilities of magnetically ordered
states (dipolar ordering) towards higher multipolar orderings. We illustrate
these advantages by applying the GSWT to a bilinear-biquadratic model of
arbitrary spin $S$ on hypercubic lattices.


title: Thermodynamics of large N gauge theory from top down holography

abstract:
  By considering fluxes on D7 branes and explicitly computing their
back-reaction on the geometry with and without a black hole, we show how the UV
divergence of Klebanov-Strassler model can be regulated. Using the form of the
metric and fluxes in the extremal and non-extremal limit, we compute the
on-shell gravity action including the localized sources up to linear order in
perturbation parameter g_sM^2/N, g_sN_f where N,M and N_f are units of D3,D5
and D7 charges in the dual gauge theory. Using the gravitational description,
we show how the gauge theory undergoes a first-order Hawking-Page like phase
transition and compute the critical temperature T_c. Finally, we obtain the
equation of state for the gauge theory by computing thermodynamic state
functions of the black hole and exhibit how black holes in deformed cone
geometry can lead to results that are qualitatively similar to lattice QCD
simulations.


title: Invariant vector fields and groupoids

abstract:
  We use the notion of isomorphism between two invariant vector fields to shed
new light on the issue of linearization of an invariant vector field near a
relative equilibrium. We argue that the notion is useful in understanding the
passage from the space of invariant vector fields in a tube around a group
orbit to the space invariant vector fields on a slice to the orbit. The notion
comes from Hepworth's study of vector fields on stacks.


title: Electrocapillary instability of magnetic fluid peak

abstract:
  The paper presents an experimental study of the capillary electrostatic
instability occurring under effect of a constant electric field on a magnetic
fluid individual peak. The peaks under study occur at disintegration of a
magnetic fluid layer applied on a flat electrode surface under effect of a
perpendicular magnetic field. The electrocapillary instability shows itself as
an emission of charged drops jets from the peak point in direction of the
opposing electrode. The charged drops emission repeats periodically and results
in the peak shape pulsations. It is shown that a magnetic field affects the
electrocapillary instability occurrence regularities and can stimulate its
development. The critical electric and magnetic field strengths at which the
instability occurs have been measured; their dependence on the peak size is
shown. The hysteresis in the system has been studied; it consists in that the
charged drops emission stops at a lesser electric (or magnetic) field strength
than that of the initial occurrence. The peak pulsations frequency depending on
the magnetic and electric field strengths and on the peak size has been
measured.


title:
The Tenth Data Release of the Sloan Digital Sky Survey: First
  Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic
  Evolution Experiment

abstract:
  The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April.
This paper presents the tenth public data release (DR10) from its current
incarnation, SDSS-III. This data release includes the first spectroscopic data
from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along
with spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS)
taken through 2012 July. The APOGEE instrument is a near-infrared R~22,500
300-fiber spectrograph covering 1.514--1.696 microns. The APOGEE survey is
studying the chemical abundances and radial velocities of roughly 100,000 red
giant star candidates in the bulge, bar, disk, and halo of the Milky Way. DR10
includes 178,397 spectra of 57,454 stars, each typically observed three or more
times, from APOGEE. Derived quantities from these spectra (radial velocities,
effective temperatures, surface gravities, and metallicities) are also
included.DR10 also roughly doubles the number of BOSS spectra over those
included in the ninth data release. DR10 includes a total of 1,507,954 BOSS
spectra, comprising 927,844 galaxy spectra; 182,009 quasar spectra; and 159,327
stellar spectra, selected over 6373.2 square degrees.


title:
Violation of Fundamental Thermodynamic Law or Invalid Microstate
  Densities?

abstract:
  It is often incorrectly assumed that the number of microstates \Omega
(E,V,N,...) available to an isolated system can have arbitrary dependence on
the extensive variables E,V,N, .... However, this is not the case for natural
systems which can reach thermodynamic equilibrium since restrictions exist
arising from the underlying equilibrium axioms of independence and \it{a
priori} equal probability of microstate, and the fundamental constants of
Nature. Here we derive a concise formula specifying the condition on \Omega
which must be met for real systems. Models which do not respect this condition
will present inconsistencies when treated under equilibrium thermodynamic
formalism. This has relevance to a number of recent models in which negative
heat capacity and violation of fundamental thermodynamic law have been
reported. Natural quantum systems obey the axioms and abide by the fundamental
constants, and thus natural systems, in the absence of infinite range forces,
can, in principle, attain thermodynamic equilibrium.


title:
Exact deterministic representation of Markovian SIR epidemics on
  networks with and without loops

abstract:
  In a previous paper Sharkey et al. [13] proved the exactness of closures at
the level of triples for Markovian SIR (susceptible-infected-removed) dynamics
on tree-like networks. This resulted in a deterministic representation of the
epidemic dynamics on the network that can be numerically evaluated. In this
paper, we extend this modelling framework to certain classes of networks
exhibiting loops. We show that closures where the loops are kept intact are
exact, and lead to a simplified and numerically solvable system of ODEs
(ordinary-differential-equations). The findings of the paper lead us to a
generalisation of closures that are based on partitioning the network around
nodes that are cut-vertices (i.e. the removal of such a node leads to the
network breaking down into at least two disjointed components or subnetworks).
Exploiting this structural property of the network yields some natural
closures, where the evolution of a particular state can typically be exactly
given in terms of the corresponding or projected sates on the subnetworks and
the cut-vertex. A byproduct of this analysis is an alternative probabilistic
proof of the exactness of the closures for tree-like networks presented in
Sharkey et al. [13]. In this paper we also elaborate on how the main result can
be applied to more realistic networks, for which we write down the ODEs
explicitly and compare output from these to results from simulation.
Furthermore, we give a general, recipe-like method of how to apply the
reduction by closures technique for arbitrary networks, and give an upper bound
on the maximum number of equations needed for an exact representation.


title: Holography of the BTZ Black Hole, Inside and Out

abstract:
  We propose a 1+1 dimensional CFT dual structure for quantum gravity and
matter on the extended 2+1 dimensional BTZ black hole, realized as a quotient
of the Poincare patch of AdS$_3$. The quotient spacetime includes regions
beyond the singularity, "whiskers", containing timelike and lightlike closed
curves, which at first sight seem unphysical. The spacetime includes the usual
AdS-asymptotic boundaries outside the horizons as well as boundary components
inside the whiskers. We show that local boundary correlators with some
endpoints in the whisker regions: (i) are a protected class of amplitudes,
dominated by effective field theory even when the associated Witten diagrams
appear to traverse the singularity, (ii) describe well-defined
diffeomorphism-invariant quantum gravity amplitudes in BTZ, (iii) sharply probe
some of the physics inside the horizon but outside the singularity, and (iv)
are equivalent to correlators of specific non-local CFT operators in the
standard thermofield entangled state of two CFTs. In this sense, the whisker
regions can be considered as purely auxiliary spacetimes in which these useful
non-local CFT correlators can be rendered as local boundary correlators, and
their diagnostic value more readily understood. Our results follow by first
performing a novel reanalysis of the Rindler view of standard AdS/CFT duality
on the Poincare patch of AdS, followed by exploiting the simple quotient
structure of BTZ which turns the Rindler horizon into the BTZ black hole
horizon. While most of our checks are within gravitational effective field
theory, we arrive at a fully non-perturbative CFT proposal to probe the
UV-sensitive approach to the singularity.


title: l-modular representations of unramified p-adic U(2,1)

abstract:
  We construct all cuspidal l-modular representations of a unitary group in
three variables attached to an unramified extension of local fields of odd
residual characteristic p with l\neq p. We describe the l-modular principal
series and show that the supercuspidal support of an irreducible l-modular
representation is unique up to conjugacy.


title:
Two operators on sandpile configurations, the sandpile model on the
  complete bipartite graph, and a Cyclic Lemma

abstract:
  We introduce two operators on stable configurations of the sandpile model
that provide an algorithmic bijection between recurrent and parking
configurations. This bijection preserves their equivalence classes with respect
to the sandpile group. The study of these operators in the special case of the
complete bipartite graph ${K}_{m,n}$ naturally leads to a generalization of the
well known Cyclic Lemma of Dvoretsky and Motzkin, via pairs of periodic
bi-infinite paths in the plane having slightly different slopes. We achieve our
results by interpreting the action of these operators as an action on a point
in the grid $\mathbb{Z}^2$ which is pointed to by one of these pairs of paths.
Our Cyclic lemma allows us to enumerate several classes of polyominoes, and
therefore builds on the work of Irving and Rattan (2009), Chapman et al.
(2009), and Bonin et al. (2003).


title:
Computing the full two-loop gluon Regge trajectory within Lipatov's high
  energy effective action

abstract:
  We discuss computational details of our recent result, namely, the first
derivation of the two-loop gluon Regge trajectory within the framework of
Lipatov's high energy effective action. In particular, we elaborate on the
direct evaluation of Feynman two-loop diagrams by using the Mellin-Barnes
representations technique. Our result is in precise agreement with previous
computations in the literature, providing this way a highly non-trivial test of
the effective action and the proposed subtraction and renormalization scheme
combined with our approach for the treatment of the loop diagrams.


title: Stability and roughness of tensile cracks in disordered materials

abstract:
  We study the stability and roughness of propagating cracks in heterogeneous
brittle two-dimensional elastic materials. We begin by deriving an equation of
motion describing the dynamics of such a crack in the framework of Linear
Elastic Fracture Mechanics, based on the Griffith criterion and the Principle
of Local Symmetry. This result allows us to extend the stability analysis of
Cotterell and Rice to disordered materials. In the stable regime we find
stochastic crack paths. Using tools of statistical physics we obtain the power
spectrum of these paths and their probability distribution function, and
conclude they do not exhibit self-affinity. We show that a real-space fractal
analysis of these paths can lead to the wrong conclusion that the paths are
self-affine. To complete the picture, we unravel the systematic bias in such
real-space methods, and thus contribute to the general discussion of
reliability of self-affine measurements.

categories: cond-mat.dis-nn cond-mat.mtrl-sci cond-mat.soft cond-mat.stat-mech nlin.PS


title:
Non-Markovian Dynamical Maps: Numerical Processing of Open Quantum
  Trajectories

abstract:
  The initial stages of the evolution of an open quantum system encode the key
information of its underlying dynamical correlations, which in turn can predict
the trajectory at later stages. We propose a general approach based on
non-Markovian dynamical maps to extract this information from the initial
trajectories and compress it into non-Markovian transfer tensors. Assuming
time-translational invariance, the tensors can be used to accurately and
efficiently propagate the state of the system to arbitrarily long timescales.
The non-Markovian Transfer Tensor Method (TTM) demonstrates the
coherent-to-incoherent transition as a function of the strength of quantum
dissipation and predicts the non-canonical equilibrium distribution due to the
system-bath entanglement. TTM is equivalent to solving the Nakajima-Zwanzig
equation, and therefore can be used to reconstruct the dynamical operators (the
system Hamiltonian and memory kernel) from quantum trajectories obtained in
simulations or experiments. The concept underlying the approach can be
generalized to physical observables with the goal of learning and manipulating
the trajectories of an open quantum system.


title: Dispelling the Quantum Spooks -- a Clue that Einstein Missed?

abstract:
  It is well-known that Bell's Theorem and other No Hidden Variable theorems
have a "retrocausal loophole", because they assume that the values of
pre-existing hidden variables are independent of future measurement settings.
(This is often referred to, misleadingly, as the assumption of "free will".)
However, it seems to have gone unnoticed until recently that a violation of
this assumption is a straightforward consequence of time-symmetry, given an
understanding of the quantization of light that would have seemed natural to
Einstein after 1905. The new argument shows precisely why quantization makes a
difference, and why time-symmetry alone does not imply retrocausality, in the
classical context. It is true that later developments in quantum theory provide
a way to avoid retrocausality, without violating time-symmetry; but this escape
route relies on the "ontic" conception of the wave function that Einstein
rejected. Had this new argument been noticed much sooner, then, it seems likely
that retrocausality would have been regarded as the default option for hidden
variables theories (a fact that would then have seemed confirmed by Bell's
Theorem and the No Hidden Variable theorems). This paper presents these ideas
at a level intended to be accessible to general readers.


title:
The effect of dispersive optical phonons on the behaviour of a Holstein
  polaron

abstract:
  We use the approximation-free Bold Diagrammatic Monte Carlo technique to
study the effects of a finite dispersion of the optical phonon mode on the
properties of the Holstein polaron, especially its effective mass. For weak
electron-phonon coupling the effect is very small, but it becomes significant
for moderate and large electron-phonon coupling. The effective mass is found to
increase (decrease) if the phonon dispersion has a negative (positive)
curvature at the centre of the Brillouin zone.


title:
Symmetry Energy Constraints from Giant Resonances: A Theoretical
  Overview

abstract:
  Giant resonances encapsulate the dynamic response of the nuclear ground state
to external perturbations. As such, they offer a unique view of the nucleus
that is often not accessible otherwise. Although interesting in their own
right, giant resonances are also enormously valuable in providing stringent
constraints on the equation of state of asymmetric matter. We this view in
mind, we focus on two modes of excitation that are essential in reaching this
goal: the isoscalar giant monopole resonance (GMR) and the isovector giant
dipole resonance (GDR). GMR energies in heavy nuclei are sensitive to the
symmetry energy because they probe the incompressibility of neutron-rich
matter. Unfortunately, access to the symmetry energy is hindered by the
relatively low neutron-proton asymmetry of stable nuclei. Thus, the measurement
of GMR energies in exotic nuclei is strongly encouraged. In the case of the
GDR, we find the electric dipole polarizability of paramount importance.
Indeed, the electric dipole polarizability appears as one of two laboratory
observables -- with the neutron-skin thickness being the other -- that are
highly sensitive to the density dependence of the symmetry energy. Finally, we
identify the softness of skin and the nature of the pygmy resonance as
important unsolved problems in nuclear structure.


title: On the threshold for rainbow connection number r in random graphs

abstract:
  We call an edge colouring of a graph G a rainbow colouring if every pair of
vertices is joined by a rainbow path, i.e., a path where no two edges have the
same colour. The minimum number of colours required for a rainbow colouring of
the edges of G is called the rainbow connection number (or rainbow
connectivity) rc(G) of G. We investigate sharp thresholds in the
Erd\H{o}s-R\'enyi random graph for the property "rc(G) <= r" where r is a fixed
integer. It is known that for r=2, rainbow connection number 2 and diameter 2
happen essentially at the same time in random graphs. For r >= 3, we conjecture
that this is not the case, propose an alternative threshold, and prove that
this is an upper bound for the threshold for rainbow connection number r.


title:
Simulating full QCD at nonzero density using the complex Langevin
  equation

abstract:
  The complex Langevin method is extended to full QCD at non-zero chemical
potential. The use of gauge cooling stabilizes the simulations at small enough
lattice spacings. At large fermion mass the results are compared to the HQCD
approach, in which the spatial hoppings of fermionic variables are neglected,
and good agreement is found. The method allows simulations also at high
densities, all the way up to saturation.


title: On the sign patterns of the smallest signless Laplacian eigenvector

abstract:
  Let $H$ be a connected bipartite graph, whose signless Laplacian matrix is
$Q(H)$. Suppose that the bipartition of $H$ is $(S,T)$ and that $x$ is the
eigenvector of the smallest eigenvalue of $Q(H)$. It is well-known that $x$ is
positive and constant on $S$, and negative and constant on $T$.
  The resilience of the sign pattern of $x$ under addition of edges into the
subgraph induced by either $S$ or $T$ is investigated and a number of cases in
which the sign pattern of $x$ persists are described.


title:
Monte Carlo techniques in small-x physics: Formal studies and
  phenomenology

abstract:
  We discuss the solution to the BFKL equation in the adjoint representation at
LO and NLO accuracy for the N = 4 SUSY theory. We use Monte Carlo techniques to
study numerically the Gluon Green's function at LO and NLO directly written in
the transverse momentum space which allows for the factorization of its
infrared divergencies. Finally, we discuss the applicability of our approach to
phenomenological searches for the BKP Odderon at the LHC.


title:
From Landscape to Portrait: A New Approach for Outlier Detection in Load
  Curve Data

abstract:
  In power systems, load curve data is one of the most important datasets that
are collected and retained by utilities. The quality of load curve data,
however, is hard to guarantee since the data is subject to communication
losses, meter malfunctions, and many other impacts. In this paper, a new
approach to analyzing load curve data is presented. The method adopts a new
view, termed \textit{portrait}, on the load curve data by analyzing the
periodic patterns in the data and re-organizing the data for ease of analysis.
Furthermore, we introduce algorithms to build the virtual portrait load curve
data, and demonstrate its application on load curve data cleansing. Compared to
existing regression-based methods, our method is much faster and more accurate
for both small-scale and large-scale real-world datasets.


title: Local, Smooth, and Consistent Jacobi Set Simplification

abstract:
  The relation between two Morse functions defined on a common domain can be
studied in terms of their Jacobi set. The Jacobi set contains points in the
domain where the gradients of the functions are aligned. Both the Jacobi set
itself as well as the segmentation of the domain it induces have shown to be
useful in various applications. Unfortunately, in practice functions often
contain noise and discretization artifacts causing their Jacobi set to become
unmanageably large and complex. While there exist techniques to simplify Jacobi
sets, these are unsuitable for most applications as they lack fine-grained
control over the process and heavily restrict the type of simplifications
possible.
  In this paper, we introduce a new framework that generalizes critical point
cancellations in scalar functions to Jacobi sets in two dimensions. We focus on
simplifications that can be realized by smooth approximations of the
corresponding functions and show how this implies simultaneously simplifying
contiguous subsets of the Jacobi set. These extended cancellations form the
atomic operations in our framework, and we introduce an algorithm to
successively cancel subsets of the Jacobi set with minimal modifications
according to some user-defined metric. We prove that the algorithm is correct
and terminates only once no more local, smooth and consistent simplifications
are possible. We disprove a previous claim on the minimal Jacobi set for
manifolds with arbitrary genus and show that for simply connected domains, our
algorithm reduces a given Jacobi set to its simplest configuration.


title:
Empirical evidences for a planetary modulation of total solar irradiance
  and the TSI signature of the 1.09-year Earth-Jupiter conjunction cycle

abstract:
  The time series of total solar irradiance (TSI) satellite observations since
1978 provided by ACRIM and PMOD TSI composites are studied. We find empirical
evidence for planetary-induced forcing and modulation of solar activity. Power
spectra and direct data pattern analysis reveal a clear signature of the
1.09-year Earth-Jupiter conjunction cycle, in particular during solar cycle 23
maximum. This appears to suggest that the Jupiter side of the Sun is slightly
brighter during solar maxima. The effect is observed when the Earth crosses the
Sun-Jupiter conjunction line every 1.09 years. Multiple spectral peaks are
observed in the TSI records that are coherent with known planetary harmonics
such as the spring, orbital and synodic periods among Mercury, Venus, Earth and
Jupiter: the Mercury-Venus spring-tidal cycle (0.20 year); the Mercury orbital
cycle (0.24 year); the Venus-Jupiter spring-tidal cycle (0.32 year); the
Venus-Mercury synodic cycle (0.40 year); the Venus-Jupiter synodic cycle (0.65
year); and the Venus-Earth spring tidal cycle (0.80 year). Strong evidence is
also found for a 0.5-year TSI cycle that could be driven by the Earth's
crossing the solar equatorial plane twice a year and may indicate a latitudinal
solar-luminosity asymmetry. Because both spring and synodic planetary cycles
appear to be present and the amplitudes of their TSI signatures appear enhanced
during sunspot cycle maxima, we conjecture that on annual and sub-annual scales
both gravitational and electro-magnetic planet-sun interactions and internal
non-linear feedbacks may be modulating solar activity. Gravitational tidal
forces should mostly stress spring cycles while electro-magnetic forces could
be linked to the solar wobbling dynamics, and would mostly stress the synodic
cycles.


title: Experimental recovery of a qubit from partial collapse

abstract:
  We describe and implement a method to restore the state of a single qubit, in
principle perfectly, after it has partially collapsed. The method resembles the
classical Hahn spin-echo, but works on a wider class of relaxation processes,
in which the quantum state partially leaves the computational Hilbert space. It
is not guaranteed to work every time, but successful outcomes are heralded. We
demonstrate using a single trapped ion better performance from this recovery
method than can be obtained employing projection and post-selection alone. The
demonstration features a novel qubit implementation that permits both partial
collapse and coherent manipulations with high fidelity.


title: On the progenitor of the Type Ic SN 2013dk in the Antennae Galaxies

abstract:
  We report the results of our search for the progenitor candidate of SN
2013dk, a Type Ic supernova (SN) that exploded in the Antennae Galaxy system.
We compare pre-explosion Hubble Space Telescope (HST) archival images with SN
images obtained using adaptive optics at the ESO Very Large Telescope. We
isolate the SN position to within 3 sigma uncertainty radius of 0.02", and show
that there is no detectable point source in any of the HST filter images within
the error circle. We set an upper limit to the absolute magnitude of the
progenitor to be M_F555W > -5.7, which does not allow Wolf-Rayet (WR) star
progenitors to be ruled out. A bright source appears 0.17" away, which is
either a single bright supergiant or compact cluster, given its absolute
magnitude of M_F555W=-9.02 +- 0.28 extended wings and complex environment.
However, even if this is a cluster, the spatial displacement of SN 2013dk means
that its membership is not assured. The strongest statement we can make is that
in the immediate environment of SN 2013dk (within 10 pc or so) we find no clear
evidence of either a point source coincident with the SN or a young stellar
cluster that could host a massive WR progenitor.


title:
A path integral formulation of the Wright-Fisher process with genic
  selection

abstract:
  The Wright-Fisher process with selection is an important tool in population
genetics theory. Traditional analysis of this process relies on the diffusion
approximation. The diffusion approximation is usually studied in a partial
differential equations framework. In this paper, I introduce a path integral
formalism to study the Wright-Fisher process with selection and use that
formalism to obtain a simple perturbation series to approximate the transition
density. The perturbation series can be understood in terms of Feynman
diagrams, which have a simple probabilistic interpretation in terms of
selective events. The perturbation series proves to be an accurate
approximation of the transition density for weak selection and is shown to be
arbitrarily accurate for any selection coefficient.


title: Household Electricity Consumption Data Cleansing

abstract:
  Load curve data in power systems refers to users' electrical energy
consumption data periodically collected with meters. It has become one of the
most important assets for modern power systems. Many operational decisions are
made based on the information discovered in the data. Load curve data, however,
usually suffers from corruptions caused by various factors, such as data
transmission errors or malfunctioning meters. To solve the problem, tremendous
research efforts have been made on load curve data cleansing. Most existing
approaches apply outlier detection methods from the supply side (i.e.,
electricity service providers), which may only have aggregated load data. In
this paper, we propose to seek aid from the demand side (i.e., electricity
service users). With the help of readily available knowledge on consumers'
appliances, we present a new appliance-driven approach to load curve data
cleansing. This approach utilizes data generation rules and a Sequential Local
Optimization Algorithm (SLOA) to solve the Corrupted Data Identification
Problem (CDIP). We evaluate the performance of SLOA with real-world trace data
and synthetic data. The results indicate that, comparing to existing load data
cleansing methods, such as B-spline smoothing, our approach has an overall
better performance and can effectively identify consecutive corrupted data.
Experimental results also demonstrate that our method is robust in various
tests. Our method provides a highly feasible and reliable solution to an
emerging industry application.


title:
Understanding Polarization Properties of InAs Quantum Dots by Atomistic
  Modeling of Growth Dynamics

abstract:
  A model for realistic InAs quantum dot composition profile is proposed and
analyzed, consisting of a double region scheme with an In-rich internal core
and an In-poor external shell, in order to mimic the atomic scale phenomena
such as In-Ga intermixing and In segregation during the growth and overgrowth
with GaAs. The parameters of the proposed model are derived by reproducing the
experimentally measured polarization data. Further understanding is developed
by analyzing the strain fields which suggests that the two-composition model
indeed results in lower strain energies than the commonly applied uniform
composition model.


title: The Population Genetic Signature of Polygenic Local Adaptation

abstract:
  Adaptation in response to selection on polygenic phenotypes may occur via
subtle allele frequencies shifts at many loci. Current population genomic
techniques are not well posed to identify such signals. In the past decade,
detailed knowledge about the specific loci underlying polygenic traits has
begun to emerge from genome-wide association studies (GWAS). Here we combine
this knowledge from GWAS with robust population genetic modeling to identify
traits that may have been influenced by local adaptation. We exploit the fact
that GWAS provide an estimate of the additive effect size of many loci to
estimate the mean additive genetic value for a given phenotype across many
populations as simple weighted sums of allele frequencies. We first describe a
general model of neutral genetic value drift for an arbitrary number of
populations with an arbitrary relatedness structure. Based on this model we
develop methods for detecting unusually strong correlations between genetic
values and specific environmental variables, as well as a generalization of
$Q_{ST}/F_{ST}$ comparisons to test for over-dispersion of genetic values among
populations. Finally we lay out a framework to identify the individual
populations or groups of populations that contribute to the signal of
overdispersion. These tests have considerably greater power than their single
locus equivalents due to the fact that they look for positive covariance
between like effect alleles, and also significantly outperform methods that do
not account for population structure. We apply our tests to the Human Genome
Diversity Panel (HGDP) dataset using GWAS data for height, skin pigmentation,
type 2 diabetes, body mass index, and two inflammatory bowel disease datasets.
This analysis uncovers a number of putative signals of local adaptation, and we
discuss the biological interpretation and caveats of these results.


title: Geometric Inference on Kernel Density Estimates

abstract:
  We show that geometric inference of a point cloud can be calculated by
examining its kernel density estimate with a Gaussian kernel. This allows one
to consider kernel density estimates, which are robust to spatial noise,
subsampling, and approximate computation in comparison to raw point sets. This
is achieved by examining the sublevel sets of the kernel distance, which
isomorphically map to superlevel sets of the kernel density estimate. We prove
new properties about the kernel distance, demonstrating stability results and
allowing it to inherit reconstruction results from recent advances in
distance-based topological reconstruction. Moreover, we provide an algorithm to
estimate its topology using weighted Vietoris-Rips complexes.


title:
Improving the efficiency of Monte Carlo simulations of systems that
  undergo temperature-driven phase transitions

abstract:
  Recently, Velazquez and Curilef have proposed a methodology to extend Monte
Carlo algorithms based on canonical ensemble, which is aimed to overcome slow
sampling problems associated with temperature-driven discontinuous phase
transitions. We show in this work that Monte Carlo algorithms extended with
this methodology also exhibit a remarkable efficiency near a critical point.
Our study is performed for the particular case of 2D four-state Potts model on
the square lattice with periodic boundary conditions. This analysis reveals
that the extended version of Metropolis importance sample is more efficient
than the usual Swendsen-Wang and Wolff cluster algorithms. These results
demonstrate the effectiveness of this methodology to improve the efficiency of
MC simulations of systems that undergo any type of temperature-driven phase
transition.


title:
Curvature of fluctuation geometry and its implications on Riemannian
  fluctuation theory

abstract:
  Fluctuation geometry was recently proposed as a counterpart approach of
Riemannian geometry of inference theory. This theory describes the geometric
features of the statistical manifold $\mathcal{M}$ of random events that are
described by a family of continuous distributions $dp(x|\theta)$. A main goal
of this work is to clarify the statistical relevance of Levi-Civita curvature
tensor $R_{ijkl}(x|\theta)$ of the statistical manifold $\mathcal{M}$. For this
purpose, the notion of \emph{irreducible statistical correlations} is
introduced. Specifically, a distribution $dp(x|\theta)$ exhibits irreducible
statistical correlations if every distribution $dp(\check{x}|\theta)$ obtained
from $dp(x|\theta)$ by considering a coordinate change $\check{x}=\phi(x)$
cannot be factorized into independent distributions as
$dp(\check{x}|\theta)=\prod_{i}dp^{(i)}(\check{x}^{i}|\theta)$. It is shown
that the curvature tensor $R_{ijkl}(x|\theta)$ arises as a direct indicator
about the existence of irreducible statistical correlations. Moreover, the
curvature scalar $R(x|\theta)$ allows to introduce a criterium for the
applicability of the \emph{gaussian approximation} of a given distribution
function. This type of asymptotic result is obtained in the framework of the
second-order geometric expansion of the distributions family $dp(x|\theta)$,
which appears as a counterpart development of the high-order asymptotic theory
of statistical estimation. In physics, fluctuation geometry represents the
mathematical apparatus of a Riemannian extension for Einstein's fluctuation
theory of statistical mechanics. Some exact results of fluctuation geometry are
now employed to derive the \emph{invariant fluctuation theorems}.


title: Twisted Injectivity in PEPS and the Classification of Quantum Phases

abstract:
  We introduce a class of projected entangled pair states (PEPS) which is based
on a group symmetry twisted by a 3-cocycle of the group. This twisted symmetry
gives rise to a new standard form for PEPS from which we construct a family of
local Hamiltonians which are gapped, frustration-free and include fixed points
of the renormalization group flow. Moreover, we advance the classification of
2D gapped quantum spin systems by showing how this new standard form for PEPS
determines the emergent topological order of these local Hamiltonians.
Specifically, we identify their universality class as Dijkgraaf-Witten
topological quantum field theory (TQFT).


title:
Evidence for an anomalous current phase relation in topological
  insulator Josephson junctions

abstract:
  Josephson junctions with topological insulator weak links can host low energy
Andreev bound states giving rise to a current phase relation that deviates from
sinusoidal behaviour. Of particular interest are zero energy Majorana bound
states that form at a phase difference of $\pi$. Here we report on
interferometry studies of Josephson junctions and superconducting quantum
interference devices (SQUIDs) incorporating topological insulator weak links.
We find that the nodes in single junction diffraction patterns and SQUID
oscillations are lifted and independent of chemical potential. At high
temperatures, the SQUID oscillations revert to conventional behaviour, ruling
out asymmetry. The node lifting of the SQUID oscillations is consistent with
low energy Andreev bound states exhibiting a nonsinusoidal current phase
relation, coexisting with states possessing a conventional sinusoidal current
phase relation. However, the finite nodal currents in the single junction
diffraction pattern suggest an anomalous contribution to the supercurrent
possibly carried by Majorana bound states, although we also consider the
possibility of inhomogeneity.


title: A counterexample to the geometric Chevalley-Warning conjecture

abstract:
  We construct a quartic threefold with L-rational singularities which has
torsion in its middle homology group. This answers a question of Brown and
Schnetz for all fields of characteristic zero.


title: Policy as Types

abstract:
  Drossopoulou and Noble argue persuasively for the need for a means to express
policy in object-capability-based systems. We investigate a practical means to
realize their aim via the Curry-Howard isomorphism. Specifically, we
investigate representing policy as types in a behavioral type system for the
RHO-calculus, a reflective higher-order variant of the pi-calculus.


title:
Tidal Tails of Minor Mergers II: Comparing Star Formation in the Tidal
  Tails of NGC 2782

abstract:
  The peculiar spiral NGC 2782 is the result of a minor merger with a mass
ratio ~4:1 occurring ~200 Myr ago. This merger produced a molecular and HI
rich, optically bright Eastern tail and an HI-rich, optically faint Western
tail. Non-detection of CO in the Western Tail by Braine et al. (2001) suggested
that star formation had not yet begun. However, deep UBVR and H-alpha
narrowband images show evidence of recent star formation in the Western tail,
though it lacks massive star clusters and cluster complexes. Using Herschel
PACS spectroscopy, we discover 158 micron [CII] emission at the location of the
three most luminous H-alpha sources in the Eastern tail, but not at the
location of the even brighter H-alpha source in the Western tail. The Western
tail is found to have a normal star formation efficiency (SFE), but the Eastern
tail has a low SFE. The lack of CO and [CII] emission suggests the Western tail
HII region may have a low carbon abundance and be undergoing its first star
formation. The Western tail is more efficient at forming stars, but lacks
massive clusters. We propose that the low SFE in the Eastern tail may be due to
its formation as a splash region where gas heating is important even though it
has sufficient molecular and neutral gas to make massive star clusters. The
Western tail, which has lower gas surface density and does not form high mass
star clusters, is a tidally formed region where gravitational compression
likely enhances star formation.


title: Networks of Josephson junctions and their synchronization

abstract:
  One can demonstrate that a 1-D Josephson network containing junctions with
different resistances can be synchronized at frequencies, which are multiples
of 2eV, where V is the total d.c. voltage applied across the network. The
appearance of such synchronization follows from the law of charge conservation
and takes place if charge transfer is dominated by the Josephson channel. One
can observe also a sub-harmonic structure. The result holds for cluster-based
arrays as well as for general case of a tunneling network.


title:
Duality between coalescence times and exit points in last-passage
  percolation models

abstract:
  In this paper we prove a duality relation between coalescence times and exit
points in last-passage percolation models with exponential weights. As a
consequence, we get lower bounds for coalescence times with scaling exponent
3/2, and we relate its distribution with variational problems involving the
Brownian motion process and the Airy process.


title: A Connection between Good Rate-distortion Codes and Backward DMCs

abstract:
  Let $X^n\in\mathcal{X}^n$ be a sequence drawn from a discrete memoryless
source, and let $Y^n\in\mathcal{Y}^n$ be the corresponding reconstruction
sequence that is output by a good rate-distortion code. This paper establishes
a property of the joint distribution of $(X^n,Y^n)$. It is shown that for
$D>0$, the input-output statistics of a $R(D)$-achieving rate-distortion code
converge (in normalized relative entropy) to the output-input statistics of a
discrete memoryless channel (dmc). The dmc is "backward" in that it is a
channel from the reconstruction space $\mathcal{Y}^n$ to source space
$\mathcal{X}^n$. It is also shown that the property does not necessarily hold
when normalized relative entropy is replaced by variational distance.


title: Relative Hilbert schemes and moduli spaces of torsion plane sheaves

abstract:
  We find certain relations between flag Hilbert schemes of points on plane
curves and moduli spaces of one-dimensional plane sheaves. We show that some of
these moduli spaces are unirational.


title: Bulk Energization of Electrons in Solar Flares by Alfv\'en Waves

abstract:
  Bulk energization of electrons to $10\,-\,20\,$keV in solar flares is
attributed to dissipation of Alfv\'en waves that transport energy and potential
downward to an acceleration region near the chromosphere. The acceleration
involves the parallel electric field that develops in the limit of inertial
Alfv\'en waves (IAWs). A two-potential model for IAWs is used to relate the
parallel potential to the cross-field potential transported by the waves. We
identify a maximum parallel potential in terms of a maximum current density
that corresponds to the threshold for the onset of anomalous resistivity. This
maximum is of order $10\,$kV when the threshold is that for the Buneman
instability. We argue that this restricts the cross-field potential in an
Alfv\'en wave to about $10\,$kV. Effective dissipation requires a large number
of up- and down-current paths associated with multiple Alfv\'en waves. The
electron acceleration occurs in localized, transient, anomalously-conducting
regions (LTACRs) and is associated with the parallel electric field determined
by Ohm's law with an anomalous resistivity. We introduce an idealized model in
which the LTACRs are (upward-)current sheets, a few skin depths in thickness,
separated by much-larger regions of weaker return current. We show that this
model can account semi-quantitatively for bulk energization.


title: Correlators of Circular Wilson Loops from Holography

abstract:
  We study the correlators of two circular Wilson loops of different radii at
strong coupling. In our setup one Wilson loop is located inside the other. We
use holography to calculate the connected two-point function. Both an AdS
background and a confining background are considered. As the computation for
the confining case cannot be carried out analytically we solve the problem
numerically. In the AdS case our results agree with similar holographic
calculations. In the case of a confining background we find an asymptotic area
law, in agreement with the result of the lattice strong coupling expansion. We
also elaborate on the subtle issue of the interplay between connected and
disconnected string worldsheets.


title: Dual potentials for capacity constrained optimal transport

abstract:
  Optimal transportation with capacity constraints, a variant of the well-known
optimal transportation problem, is concerned with transporting one probability
density $f \in L^1(\mathbb{R}^m)$ onto another one $g \in L^1(\mathbb{R}^n)$ so
as to optimize a cost function $c \in L^1(\mathbb{R}^{m+n})$ while respecting
the capacity constraints $0\le h \le \bar h\in L^\infty(\mathbb{R}^{m+n})$.
  A linear programming duality theorem for this problem was first established
by Levin. In this note, we prove under mild assumptions on the given data, the
existence of a pair of $L^1$-functions optimizing the dual problem. Using these
functions, which can be viewed as Lagrange multipliers to the marginal
constraints $f$ and $g$, we characterize the solution $h$ of the primal
problem. We expect these potentials to play a key role in any further analysis
of $h$.
  Moreover, starting from Levin's duality, we derive the classical Kantorovich
duality for unconstrained optimal transport. In tandem with results obtained in
our companion paper (arXiv:1309.3022), this amounts to a new and elementary
proof of Kantorovich's duality.


title:
A Hybrid Analog/Digital Phase-Locked Loop for Frequency Mode Non-contact
  Scanning Probe Microscopy

abstract:
  Non-contact scanning probe microscopy (SPM) has developed into a powerful
technique to image many different properties of samples. The conventional
method involves monitoring the amplitude, phase or frequency of a cantilever
oscillating at or near its resonant frequency as it is scanned across the
surface of a sample. For high Q factor cantilevers, monitoring the resonant
frequency is the preferred method in order to obtain reasonable scan times.
This can be done by using a phase-locked-loop (PLL). PLLs can be obtained as
commercial integrated circuits, but these do not have the frequency resolution
required for SPM. To increase the resolution, all-digital PLLs requiring
sophisticated digital signal processors or field programmable gate arrays have
also been implemented. We describe here a hybrid analog/digital PLL where most
of the components are implemented using discrete analog integrated circuits,
but the frequency resolution is provided by a direct digital synthesis chip
controlled by a simple PIC microcontroller. The PLL has excellent frequency
resolution and noise, and can be controlled and read by a computer via a USB
connection.


title:
Condition for Capture into First-order Mean Motion Resonances and
  Application to Constraints on Origin of Resonant Systems

abstract:
  We investigate the condition for capture into first-order mean motion
resonances using numerical simulations with a wide range of various parameters.
In particular, we focus on deriving the critical migration timescale for
capture into the 2:1 resonance; additional numerical experiments for closely
spaced resonances (e.g., 3:2) are also performed. We find that the critical
migration timescale is determined by the planet-to-stellar mass ratio, and its
dependence exhibits power-law behavior with index -4/3. This dependence is also
supported by simple analytic arguments. We also find that the critical
migration timescale for systems with equal-mass bodies is shorter than that in
the restricted problem; for instance, for the 2:1 resonance between two
equal-mass bodies, the critical timescale decreases by a factor of 10. In
addition, using the obtained formula, the origin of observed systems that
include first-order commensurabilities is constrained. Assuming that pairs of
planets originally form well separated from each other and then undergo
convergent migration and are captured in resonances, it is possible that a
number of exoplanets experienced rapid orbital migration. For systems in
closely spaced resonances, the differential migration timescale between the
resonant pair can be constrained well; it is further suggested that several
exoplanets underwent migration that can equal or even exceed the type I
migration rate predicted by the linear theory. This implies that some of them
may have formed in situ. Future observations and the use of our model will
allow us to statistically determine the typical migration speed in a
protoplanetary disk.


title:
The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay
  of Germanium-76

abstract:
  The {\sc Majorana} collaboration is searching for neutrinoless double beta
decay using $^{76}$Ge, which has been shown to have a number of advantages in
terms of sensitivities and backgrounds. The observation of neutrinoless
double-beta decay would show that lepton number is violated and that neutrinos
are Majorana particles and would simultaneously provide information on neutrino
mass. Attaining sensitivities for neutrino masses in the inverted hierarchy
region, $15 - 50$ meV, will require large, tonne-scale detectors with extremely
low backgrounds, at the level of $\sim$1 count/t-y or lower in the region of
the signal. The {\sc Majorana} collaboration, with funding support from DOE
Office of Nuclear Physics and NSF Particle Astrophysics, is constructing the
{\sc Demonstrator}, an array consisting of 40 kg of p-type point-contact
high-purity germanium (HPGe) detectors, of which $\sim$30 kg will be enriched
to 87% in $^{76}$Ge. The {\sc Demonstrator} is being constructed in a clean
room laboratory facility at the 4850' level (4300 m.w.e.) of the Sanford
Underground Research Facility (SURF) in Lead, SD. It utilizes a compact graded
shield approach with the inner portion consisting of ultra-clean Cu that is
being electroformed and machined underground. The primary aim of the {\sc
Demonstrator} is to show the feasibility of a future tonne-scale measurement in
terms of backgrounds and scalability.


title:
Lucjan Emil B\"ottcher (1872-1937)-- the Polish pioneer of holomorphic
  dynamics

abstract:
  This paper, based in part on joint work with Stanis{\l}aw Domoradzki,
concerns Lucjan Emil B\"ottcher (1872-1937)-- a little-known Polish
mathematician active in Lw\'ow. I outline B\"ottcher's scholarly path, focusing
on his studies in Leipzig with Sophus Lie, his later academic career in Lw\'ow
and the hindrances he faced in its advancement. I also describe very briefly
his mathematical achievements. In view of later developments in holomorphic
dynamics, I argue that, despite flaws in his work, B\"ottcher should be
regarded not only as a contributor to the area but in fact as one of its
founders.


title: An Overview of Load Balancing in HetNets: Old Myths and Open Problems

abstract:
  Matching the demand for resources ("load") with the supply of resources
("capacity") is a basic problem occurring across many fields of engineering,
logistics, and economics, and has been considered extensively both in the
Internet and in wireless networks. The ongoing evolution of cellular
communication networks into dense, organic, and irregular heterogeneous
networks ("HetNets") has elevated load-awareness to a central problem, and
introduces many new subtleties. This paper explains how several long-standing
assumptions about cellular networks need to be rethought in the context of a
load-balanced HetNet: we highlight these as three deeply entrenched myths that
we then dispel. We survey and compare the primary technical approaches to
HetNet load balancing: (centralized) optimization, game theory, Markov decision
processes, and the newly popular cell range expansion (a.k.a. "biasing"), and
draw design lessons for OFDMA-based cellular systems. We also identify several
open areas for future exploration.


title:
Dark matter in little Higgs model under current experimental constraints
  from LHC, Planck and Xenon

abstract:
  We examine the status of dark matter (heavy photon) in the littlest Higgs
model with T-parity (LHT) in light of the new results from the LHC Higgs
search, the Planck dark matter relic density and the XENON100 limit on the dark
matter scattering off the nucleon. We obtain the following observations: (i)
For the LHC Higgs data, the LHT can well be consistent with the CMS results but
disfavored by the ATLAS observation of diphoton enhancement; (ii) For the dark
matter relic density, the heavy photon in the LHT can account for the Planck
data for the small mass splitting of mirror lepton and heavy photon; (iii) For
the dark matter scattering off the nucleon, the heavy photon can give a
spin-independent cross section below the XENON100 upper limit for $m_{A_H}>95$
GeV ($f> 665$ GeV); (iv) A fit using the CMS Higgs data gives the lowest
chi-square of 2.63 (the SM value is 4.75) at $f\simeq$ 1120 GeV and
$m_{A_H}\simeq$ 170 GeV (at this point the dark matter constraints from Planck
and XENON100 can also be satisfied). Such a best point and its nearby favored
region (even for a $f$ value up to 3.8 TeV) can be covered by the future
XENON1T (2017) experiment.


title:
Bimodal chemical evolution of the Galactic disk and the Barium abundance
  of Cepheids

abstract:
  In order to understand the Barium abundance distribution in the Galactic disk
based on Cepheids, one must first be aware of important effects of the
corotation resonance, situated a little beyond the solar orbit. The thin disk
of the Galaxy is divided in two regions that are separated by a barrier
situated at that radius. Since the gas cannot get across that barrier, the
chemical evolution is independent on the two sides of it. The barrier is caused
by the opposite directions of flows of gas, on the two sides, in addition to a
Cassini-like ring void of HI (caused itself by the flows). A step in the
metallicity gradient developed at corotation, due to the difference in the
average star formation rate on the two sides, and to this lack of communication
between them. In connection with this, a proof that the spiral arms of our
Galaxy are long-lived (a few billion years) is the existence of this step. When
one studies the abundance gradients by means of stars which span a range of
ages, like the Cepheids, one has to take into account that stars, contrary to
the gas, have the possibility of crossing the corotation barrier. A few stars
born on the high metallicity side are seen on the low metallicity one, and
vice-versa. In the present work we re-discuss the data on Barium abundance in
Cepheids as a function of Galactic radius, taking into account the scenario
described above. The [Ba/H] ratio, plotted as a function of Galactic radius,
apparently presents a distribution with two branches in the external region
(beyond corotation). One can re-interpret the data and attribute the upper
branch to the stars that were born on the high metallicity side. The lower
branch, analyzed separately, indicates that the stars born beyond corotation
have a rising Barium metallicity as a function of Galactic radius.


title: Hyperbolicity of Force-Free Electrodynamics

abstract:
  We analyze the equations of relativistic magnetized plasma dynamics in the
limiting case that electromagnetic stress-energy is dominant over pressure and
rest mass energy density. The naive formulation of these equations is shown to
be not hyperbolic. Modifying the equations by terms that vanish for all
physical solutions, we obtain a symmetric hyperbolic evolution system, which
should exhibit improved numerical behavior.


title:
Synthesis of Self-assembled Iron Silicon Oxide Nanowires onto
  Single-crystalline Si(100)

abstract:
  Iron silicon oxide nanowire has been synthesized by putting single
crystalline Si(100) wafer into ammonium iron sulfate, hydrogen peroxide, and
triethylamine solution heated to from 70 to 100 degree in the air. The prepared
iron silicon oxide nanowires with diameters of about 10nm (onto non etched
Si(100) wafer) and about 75nm(onto etched Si(100) wafer) and their self
assembles were characterized. The possible mechanism that accounted for the
formation of iron silicon oxide nanowire is suggested based on experimental
evidence.


title:
Inference on differences between classes using cluster-specific
  contrasts of mixed effects

abstract:
  The detection of differentially expressed (DE) genes is one of the most
commonly studied problems in bioinformatics. For example, the identification of
DE genes between distinct disease phenotypes is an important first step in
understanding and developing treatment drugs for the disease. It can also
contribute significantly to the construction of a discriminant rule for
predicting the class of origin of an unclassified tissue sample from a patient.
We present a novel approach to the problem of detecting DE genes that is based
on a test statistic formed as a weighted (normalized) cluster-specific contrast
in the mixed effects of the mixture model used in the first instance to cluster
the gene profiles into a manageable number of clusters. The key factor in the
formation of our test statistic is the use of gene-specific mixed effects in
the cluster-specific contrast. It thus means that the (soft) assignment of a
given gene to a cluster is not crucial. This is because in addition to class
differences between the (estimated) fixed effects terms for a cluster,
gene-specific class differences also contribute to the cluster-specific
contributions to the final form of the test statistic. The proposed test
statistic can be used where the primary aim is to rank the genes in order of
evidence against the null hypothesis of no DE. We also show how a P-value can
be calculated for each gene for use in multiple hypothesis testing where the
intent is to control the false discovery rate (FDR) at some desired level. With
the use of real and simulated data sets, we show that the proposed
contrast-based approach outperforms other methods commonly used for the
detection of DE genes both in a ranking context with lower proportion of false
discoveries and in a multiple hypothesis testing context with higher power for
a specified level of the FDR.


title:
Potentiation Decay of Synapses and the Length Distributions of Synfire
  Chains Self-organized in Recurrent Neural Networks

abstract:
  Synfire chains are thought to underlie precisely-timed sequences of spikes
observed in various brain regions and across species. How they are formed is
not understood. Here we analyze self-organization of synfire chains through the
spike-timing dependent plasticity (STDP) of the synapses, axon remodeling, and
potentiation decay of synaptic weights in networks of neurons driven by noisy
external inputs and subject to dominant feedback inhibition. Potentiation decay
is the gradual, activity-independent reduction of synaptic weights over time.
We show that potentiation decay enables a dynamic and statistically stable
network connectivity when neurons spike spontaneously. Periodic stimulation of
a subset of neurons leads to formation of synfire chains through a random
recruitment process, which terminates when the chain connects to itself and
forms a loop. We demonstrate that chain length distributions depend on the
potentiation decay. Fast potentiation decay leads to long chains with wide
distributions, while slow potentiation decay leads to short chains with narrow
distributions. We suggest that the potentiation decay, which corresponds to the
decay of early long-term potentiation of synapses (E-LTP), is an important
synaptic plasticity rule in regulating formation of neural circuity through
STDP.


title:
A Hybrid Cryptosystem Based On Vigenere Cipher and Columnar
  Transposition Cipher

abstract:
  Privacy is one of the key issues addressed by information Security. Through
cryptographic encryption methods, one can prevent a third party from
understanding transmitted raw data over unsecured channel during signal
transmission. The cryptographic methods for enhancing the security of digital
contents have gained high significance in the current era. Breach of security
and misuse of confidential information that has been intercepted by
unauthorized parties are key problems that information security tries to solve.
This paper sets out to contribute to the general body of knowledge in the area
of classical cryptography by develop- ing a new hybrid way of encryption of
plaintext. The cryptosystem performs its encryption by encrypting the plaintext
using columnar transposition cipher and further using the ciphertext to encrypt
the plaintext again using Vigen\`ere ci- pher. At the end, cryptanalysis was
performed on the ciphertext. The implementation will be done using java
program- ming.


title:
An Integrated Geographic Information System and Marketing Information
  System Model

abstract:
  Maintaining competitive advantage is significant in this present day of
globalization, knowledge management and enormous economic activities. An
organization's future developments are influenced by its managements'
decisions. Businesses today are facing a lot of challenges in terms of
competition and they have to be in the lead by strengthening their research and
development strategies with the aid of cutting edge technologies. Hence
marketing intelligence is now a key to the success of any business in today's
rapidly changing business environment. With all the technologies available in
marketing research, businesses still struggle with how to gather information
and make decisions in a short time and real-time about their customers' needs
and purchasing patterns in various geographical areas.
  This paper is set out to contribute to the body of knowledge in the area of
the application of Geographic Information Systems technology solutions to
businesses by developing a model for integrating Geographic Information Systems
into existing Marketing Information Systems for effective marketing research.
This model will interconnect organizations at the highest levels, providing
reassurance to enable broad scope of checks and balances as well as benefiting
many business activities including operational, tactical and strategic decision
making due to its analytical and solution driven functions.


title:
Computer Aided Investigation: Visualization and Analysis of data from
  Mobile communication devices using Formal Concept Analysis

abstract:
  In this world of terrorism, it is very important to know the network of
individual suspects. It is also important to analyze the attributes of members
of a network and the relationships that exist between them either directly or
indirectly. This will make it easy for concepts to be built in aiding criminal
investigations. However traditional approaches cannot be used to visualize and
analyze data collected on individuals. With this current day where information
systems play critical role in everyday life of every individual, it is easier
to depend on digital information in fighting crime.Effective computer tools and
intelligent systems that are automated to analyze and interpret criminal data
in real time effectively and efficiently are needed in fighting crime. These
current computer systems should have the capability of providing intelligence
from raw data and creating a visual graph which will make it easy for new
concepts to be built and generated from crime data in order to solve understand
and analyze crime patterns easily. This paper proposes a new method of computer
aided investigation by visualizing and analyzing data of mobile communication
devices using Formal Concept Analysis, or Galois Lattices, a data analysis
technique grounded on Lattice Theory and Propositional Calculus. This method
considered the set of common and distinct attributes of data in such a way that
categorizations are done based on related data with respect to time and events.
This will help in building a more defined and conceptual systems for analysis
of crime data that can easily be visualized and intelligently analyzed by
computer systems.


title:
The Role of Rural Banks in Providing Mobile Money Services to Rural Poor
  Communities: An effective integration approach of Rural Banks and existing
  mobile communications infrastructure

abstract:
  The rapid spread of mobile phones means that the number of mobile users may
already exceed the number of banked people in many low income countries. Mobile
phones can also offer a communications channel for initiating and executing
on-line financial transactions. This channel may not only reduce the cost of
financial transactions for provider and customer, but also allow new entrants
to the financial sector, and new relationships to be formed for distributing
services. These changes hold the prospect of accelerating access to financial
services on the back of the mobile infrastructure. Mobile telephony offers
tremendous promise to facilitate the flow of money among rural and poor
families at much lower transaction costs, bringing the bank to those currently
unbanked. Realizing this promise will require close collaboration among all
stakeholders. But most rural banks do not have mobile banking services for
their customers. This made it difficult for the full potential and benefits of
mobile money financial services to be realized. Most telecommunication service
providers run mobile money service solely for their subscribers without an
integrated approach of incorporating and integrating rural banking systems into
their existing services this makes it difficult for a full fledge exploitation
of the mobile financial market. This paper looks at the existing mobile money
services and takes critical look at the positive advantages of effective
integration approach of Rural Banks and existing mobile communications
infrastructure as well as proposing a model for such integration.


title:
Using SOA with Web Services for effective Integration of Hospital
  Information Systems via an Enterprise Service Bus

abstract:
  Hospitals are distributed across geographical areas and it is important for
all hospitals to share information as well as integrate their systems for
effective researching and health delivery. Health personals and institutions in
need of information from hospitals with respect to geographical areas can
easily do researches on patients, treatments, disease outbreaks, and effects of
drugs. This research work is aimed at integrating of database systems of
hospital across geographical areas via a service bus. A centralized service bus
was used to facilitate interoperability of applications across platforms and
enhance communication within the hospital infrastructure as well as creating
enabling environment for new layer of abstractions to be added without
modification of the entire system. Concept of Service Oriented Architecture
with web services was used for rapid integration solution in solving the
challenges faced during integration of multiple incompatible applications.


title: A Visual Cryptographic Encryption Technique for Securing Medical Images

abstract:
  The increased growth in the use of transmission of multimedia medical
contents over unsecured and open networks provides insecurity for confidential
patient information over these networks. Digital encryption of medical images
before transmission and storage is proposed as a way to effectively provide
protection of patient information. Encryption before watermarking of these
images is necessary in order to ensure inaccessibility of information to
unauthorized personnel with patient. This paper presented a visual
cryptographic technique for encrypting of medical images before transmission or
storage of them. This will make such images inaccessible by unauthorized
personnel and also ensures confidentiality. The process made use of an
encryption technique that is based on pixel shuffling and a secret key
generated from the image.


title:
PPS: Privacy-Preserving Strategyproof Social-Efficient Spectrum Auction
  Mechanisms

abstract:
  Many spectrum auction mechanisms have been proposed for spectrum allocation
problem, and unfortunately, few of them protect the bid privacy of bidders and
achieve good social efficiency. In this paper, we propose PPS, a Privacy
Preserving Strategyproof spectrum auction framework. Then, we design two
schemes based on PPS separately for 1) the Single-Unit Auction model (SUA),
where only single channel to be sold in the spectrum market; and 2) the
Multi-Unit Auction model (MUA), where the primary user subleases multi-unit
channels to the secondary users and each of the secondary users wants to access
multi-unit channels either. Since the social efficiency maximization problem is
NP-hard in both auction models, we present allocation mechanisms with
approximation factors of $(1+\epsilon)$ and 32 separately for SUA and MUA, and
further judiciously design strategyproof auction mechanisms with privacy
preserving based on them. Our extensive evaluations show that our mechanisms
achieve good social efficiency and with low computation and communication
overhead.


title: Multi-dimensional Parametric Mincuts for Constrained MAP Inference

abstract:
  In this paper, we propose novel algorithms for inferring the Maximum a
Posteriori (MAP) solution of discrete pairwise random field models under
multiple constraints. We show how this constrained discrete optimization
problem can be formulated as a multi-dimensional parametric mincut problem via
its Lagrangian dual, and prove that our algorithm isolates all constraint
instances for which the problem can be solved exactly. These multiple solutions
enable us to even deal with `soft constraints' (higher order penalty
functions). Moreover, we propose two practical variants of our algorithm to
solve problems with hard constraints. We also show how our method can be
applied to solve various constrained discrete optimization problems such as
submodular minimization and shortest path computation. Experimental evaluation
using the foreground-background image segmentation problem with statistic
constraints reveals that our method is faster and its results are closer to the
ground truth labellings compared with the popular continuous relaxation based
methods.


title: A curious identity for Bernoulli numbers

abstract: We prove a curious identity for the Bernoulli numbers.


title:
Protein (Multi-)Location Prediction: Using Location Inter-Dependencies
  in a Probabilistic Framework

abstract:
  Knowing the location of a protein within the cell is important for
understanding its function, role in biological processes, and potential use as
a drug target. Much progress has been made in developing computational methods
that predict single locations for proteins, assuming that proteins localize to
a single location. However, it has been shown that proteins localize to
multiple locations. While a few recent systems have attempted to predict
multiple locations of proteins, they typically treat locations as independent
or capture inter-dependencies by treating each locations-combination present in
the training set as an individual location-class. We present a new method and a
preliminary system we have developed that directly incorporates
inter-dependencies among locations into the multiple-location-prediction
process, using a collection of Bayesian network classifiers. We evaluate our
system on a dataset of single- and multi-localized proteins. Our results,
obtained by incorporating inter-dependencies are significantly higher than
those obtained by classifiers that do not use inter-dependencies. The
performance of our system on multi-localized proteins is comparable to a top
performing system (YLoc+), without restricting predictions to be based only on
location-combinations present in the training set.


title: Emergence of scaling in human-interest dynamics

abstract:
  Human behaviors are often driven by human interests. Despite intense recent
efforts in exploring the dynamics of human behaviors, little is known about
human-interest dynamics, partly due to the extreme difficulty in accessing the
human mind from observations. However, the availability of large-scale data,
such as those from e-commerce and smart-phone communications, makes it possible
to probe into and quantify the dynamics of human interest. Using three
prototypical "big data" sets, we investigate the scaling behaviors associated
with human-interest dynamics. In particular, from the data sets we uncover
power-law scaling associated with the three basic quantities: (1) the length of
continuous interest, (2) the return time of visiting certain interest, and (3)
interest ranking and transition. We argue that there are three basic
ingredients underlying human-interest dynamics: preferential return to
previously visited interests, inertial effect, and exploration of new
interests. We develop a biased random-walk model, incorporating the three
ingredients, to account for the observed power-law scaling relations. Our study
represents the first attempt to understand the dynamical processes underlying
human interest, which has significant applications in science and engineering,
commerce, as well as defense, in terms of specific tasks such as recommendation
and human-behavior prediction.


title:
A Schwarz-Pick lemma for the modulus of holomorphic mappings between the
  unit balls in complex spaces

abstract:
  In this paper we prove a Schwarz-Pick lemma for the modulus of holomorphic
mappings between the unit balls in complex spaces. This extends the classical
Schwarz-Pick lemma and the related result proved by Pavlovic.


title: Towards Reliable Automatic Protein Structure Alignment

abstract:
  A variety of methods have been proposed for structure similarity calculation,
which are called structure alignment or superposition. One major shortcoming in
current structure alignment algorithms is in their inherent design, which is
based on local structure similarity. In this work, we propose a method to
incorporate global information in obtaining optimal alignments and
superpositions. Our method, when applied to optimizing the TM-score and the GDT
score, produces significantly better results than current state-of-the-art
protein structure alignment tools. Specifically, if the highest TM-score found
by TMalign is lower than (0.6) and the highest TM-score found by one of the
tested methods is higher than (0.5), there is a probability of (42%) that
TMalign failed to find TM-scores higher than (0.5), while the same probability
is reduced to (2%) if our method is used. This could significantly improve the
accuracy of fold detection if the cutoff TM-score of (0.5) is used.
  In addition, existing structure alignment algorithms focus on structure
similarity alone and simply ignore other important similarities, such as
sequence similarity. Our approach has the capacity to incorporate multiple
similarities into the scoring function. Results show that sequence similarity
aids in finding high quality protein structure alignments that are more
consistent with eye-examined alignments in HOMSTRAD. Even when structure
similarity itself fails to find alignments with any consistency with
eye-examined alignments, our method remains capable of finding alignments
highly similar to, or even identical to, eye-examined alignments.


title: Percolation Modeling of Self-Damaging of Composite Materials

abstract:
  We propose the concept of autonomous self-damaging in "smart" composite
materials, controlled by activation of added nanosize "damaging" capsules.
Percolation-type modeling approach earlier applied to the related concept of
self-healing materials, is used to investigate the behavior of the initial
material's fatigue. We aim at achieving a relatively sharp drop in the
material's integrity after some initial limited fatigue develops in the course
of the sample's usage. Our theoretical study considers a two-dimensional
lattice model and involves Monte Carlo simulations of the connectivity and
conductance in the high-connectivity regime of percolation. We give several
examples of local capsule-lattice and capsule-capsule activation rules and show
that the desired self-damaging property can only be obtained with rather
sophisticated "smart" material's response involving not just damaging but also
healing capsules.


title: Efficient Energy Minimization for Enforcing Statistics

abstract:
  Energy minimization algorithms, such as graph cuts, enable the computation of
the MAP solution under certain probabilistic models such as Markov random
fields. However, for many computer vision problems, the MAP solution under the
model is not the ground truth solution. In many problem scenarios, the system
has access to certain statistics of the ground truth. For instance, in image
segmentation, the area and boundary length of the object may be known. In these
cases, we want to estimate the most probable solution that is consistent with
such statistics, i.e., satisfies certain equality or inequality constraints.
  The above constrained energy minimization problem is NP-hard in general, and
is usually solved using Linear Programming formulations, which relax the
integrality constraints. This paper proposes a novel method that finds the
discrete optimal solution of such problems by maximizing the corresponding
Lagrangian dual. This method can be applied to any constrained energy
minimization problem whose unconstrained version is polynomial time solvable,
and can handle multiple, equality or inequality, and linear or non-linear
constraints. We demonstrate the efficacy of our method on the
foreground/background image segmentation problem, and show that it produces
impressive segmentation results with less error, and runs more than 20 times
faster than the state-of-the-art LP relaxation based approaches.


title:
Intrinsic Localized Modes in a Nonlinear Electrical Lattice with
  Saturable Nonlinearity

abstract:
  This experimental study of driven intrinsic localized modes (ILMs) in an
electronic circuit lattice with saturable nonlinearity follows the theoretical
work of Hadzievski and coworkers. They proposed that a saturable nonlinearity
could introduce transition points where localized excitations in nonintegrable
lattices would move freely. In our experiments MOS capacitors provide the
saturable nonlinearity in an electric lattice. Because of the soft nonlinearity
driver locked, auto-resonance stationary ILMs are observed below the bottom of
a linear frequency band of the lattice. With decreasing driver frequency the
width of the ILM changes in a step-wise manner as does the softening of the
barrier between site-centered and bond-centered ILM locations in agreement with
theoretical expectations. However, the steps show hysteresis between up and
down frequency scans and such hysteresis inhibits the free motion of ILMs.


title:
Constraining the Z' Mass in 331 Models using Direct Dark Matter
  Detection

abstract:
  We investigate a so-called 331 extension of the Standard Model gauge sector
which accommodates neutrino masses and where the lightest of the new neutral
fermions in the theory is a viable particle dark matter candidate. In this
model, processes mediated by the additional $Z^{\prime}$ gauge boson set both
the dark matter relic abundance and the scattering cross section off of nuclei.
We calculate with unprecedented accuracy the dark matter relic density,
including the important effect of coannihilation across the heavy fermion
sector, and show that indeed the candidate particle has the potential of having
the observed dark matter density. We find that the recent LUX results put very
stringent bounds on the mass of the extra gauge boson, $M_{Z^{\prime}} \gtrsim
2$~TeV, independently of the dark matter mass. We also comment on regime where
our bounds on the $Z^{\prime}$ mass may apply to generic 331-like models, and
on implications for LHC phenomenology.


title:
A Minimum-Labeling Approach for Reconstructing Protein Networks across
  Multiple Conditions

abstract:
  The sheer amounts of biological data that are generated in recent years have
driven the development of network analysis tools to facilitate the
interpretation and representation of these data. A fundamental challenge in
this domain is the reconstruction of a protein-protein subnetwork that
underlies a process of interest from a genome-wide screen of associated genes.
Despite intense work in this area, current algorithmic approaches are largely
limited to analyzing a single screen and are, thus, unable to account for
information on condition-specific genes, or reveal the dynamics (over time or
condition) of the process in question. Here we propose a novel formulation for
network reconstruction from multiple-condition data and devise an efficient
integer program solution for it. We apply our algorithm to analyze the response
to influenza infection in humans over time as well as to analyze a pair of ER
export related screens in humans. By comparing to an extant, single-condition
tool we demonstrate the power of our new approach in integrating data from
multiple conditions in a compact and coherent manner, capturing the dynamics of
the underlying processes.


title: Emergence of fractal in aggregation with stochastic self-replication

abstract:
  We propose and investigate a simple model which describes the kinetics of
aggregation of Brownian particles with stochastic self-replication. An exact
solution and the scaling theory are presented alongside numerical simulation
which fully support all theoretical findings. In particular, we show
analytically that the particle size distribution function exhibits dynamic
scaling and we verified it numerically using the idea of data-collapse.
Besides, the conditions under which the resulting system emerges as a fractal
are found, the fractal dimension of the system is given and the relationship
between this fractal dimension and a conserved quantity is pointed out.


title: Faster mass decomposition

abstract:
  Metabolomics complements investigation of the genome, transcriptome, and
proteome of an organism. Today, the vast majority of metabolites remain
unknown, in particular for non-model organisms. Mass spectrometry is one of the
predominant techniques for analyzing small molecules such as metabolites. A
fundamental step for identifying a small molecule is to determine its molecular
formula.
  Here, we present and evaluate three algorithm engineering techniques that
speed up the molecular formula determination. For that, we modify an existing
algorithm for decomposing the monoisotopic mass of a molecule. These techniques
lead to a four-fold reduction of running times, and reduce memory consumption
by up to 94%. In comparison to the classical search tree algorithm, our
algorithm reaches a 1000-fold speedup.


title: On NP-Hardness of the Paired de Bruijn Sound Cycle Problem

abstract:
  The paired de Bruijn graph is an extension of de Bruijn graph incorporating
mate pair information for genome assembly proposed by Mevdedev et al. However,
unlike in an ordinary de Bruijn graph, not every path or cycle in a paired de
Bruijn graph will spell a string, because there is an additional soundness
constraint on the path. In this paper we show that the problem of checking if
there is a sound cycle in a paired de Bruijn graph is NP-hard in general case.
We also explore some of its special cases, as well as a modified version where
the cycle must also pass through every edge.


title:
Finite-State Markov Modeling of Tunnel Channels in Communication-based
  Train Control (CBTC) Systems

abstract:
  Communication-based train control (CBTC) is gradually adopted in urban rail
transit systems, as it can significantly enhance railway network efficiency,
safety and capacity. Since CBTC systems are mostly deployed in underground
tunnels and trains move in high speed, building a train-ground wireless
communication system for CBTC is a challenging task. Modeling the tunnel
channels is very important to design and evaluate the performance of CBTC
systems. Most of existing works on channel modeling do not consider the unique
characteristics in CBTC systems, such as high mobility speed, deterministic
moving direction, and accurate train location information. In this paper, we
develop a finite state Markov channel (FSMC) model for tunnel channels in CBTC
systems. The proposed FSMC model is based on real field CBTC channel
measurements obtained from a business operating subway line. Unlike most
existing channel models, which are not related to specific locations, the
proposed FSMC channel model takes train locations into account to have a more
accurate channel model. The distance between the transmitter and the receiver
is divided into intervals, and an FSMC model is applied in each interval. The
accuracy of the proposed FSMC model is illustrated by the simulation results
generated from the model and the real field measurement results.


title: Automated Attack Planning

abstract:
  Penetration Testing is a methodology for assessing network security, by
generating and executing possible attacks. Doing so automatically allows for
regular and systematic testing. A key question then is how to automatically
generate the attacks. A natural way to address this issue is as an attack
planning problem. In this thesis, we are concerned with the specific context of
regular automated pentesting, and use the term "attack planning" in that sense.
The following three research directions are investigated.
  First, we introduce a conceptual model of computer network attacks, based on
an analysis of the penetration testing practices. We study how this attack
model can be represented in the PDDL language. Then we describe an
implementation that integrates a classical planner with a penetration testing
tool. This allows us to automatically generate attack paths for real world
pentesting scenarios, and to validate these attacks by executing them.
  Secondly, we present efficient probabilistic planning algorithms,
specifically designed for this problem, that achieve industrial-scale runtime
performance (able to solve scenarios with several hundred hosts and exploits).
These algorithms take into account the probability of success of the actions
and their expected cost (for example in terms of execution time, or network
traffic generated).
  Finally, we take a different direction: instead of trying to improve the
efficiency of the solutions developed, we focus on improving the model of the
attacker. We model the attack planning problem in terms of partially observable
Markov decision processes (POMDP). This grounds penetration testing in a
well-researched formalism. POMDPs allow the modelling of information gathering
as an integral part of the problem, thus providing for the first time a means
to intelligently mix scanning actions with actual exploits.


title:
Les POMDP font de meilleurs hackers: Tenir compte de l'incertitude dans
  les tests de penetration

abstract:
  Penetration Testing is a methodology for assessing network security, by
generating and executing possible hacking attacks. Doing so automatically
allows for regular and systematic testing. A key question is how to generate
the attacks. This is naturally formulated as planning under uncertainty, i.e.,
under incomplete knowledge about the network configuration. Previous work uses
classical planning, and requires costly pre-processes reducing this uncertainty
by extensive application of scanning methods. By contrast, we herein model the
attack planning problem in terms of partially observable Markov decision
processes (POMDP). This allows to reason about the knowledge available, and to
intelligently employ scanning actions as part of the attack. As one would
expect, this accurate solution does not scale. We devise a method that relies
on POMDPs to find good attacks on individual machines, which are then composed
into an attack on the network as a whole. This decomposition exploits network
structure to the extent possible, making targeted approximations (only) where
needed. Evaluating this method on a suitably adapted industrial test suite, we
demonstrate its effectiveness in both runtime and solution quality.


title: Accurate Decoding of Pooled Sequenced Data Using Compressed Sensing

abstract:
  In order to overcome the limitations imposed by DNA barcoding when
multiplexing a large number of samples in the current generation of
high-throughput sequencing instruments, we have recently proposed a new
protocol that leverages advances in combinatorial pooling design (group
testing) doi:10.1371/journal.pcbi.1003010. We have also demonstrated how this
new protocol would enable de novo selective sequencing and assembly of large,
highly-repetitive genomes. Here we address the problem of decoding pooled
sequenced data obtained from such a protocol. Our algorithm employs a
synergistic combination of ideas from compressed sensing and the decoding of
error-correcting codes. Experimental results on synthetic data for the rice
genome and real data for the barley genome show that our novel decoding
algorithm enables significantly higher quality assemblies than the previous
approach.