title:
Graph eigenvectors, fundamental weights and centrality metrics for nodes
  in networks

abstract:
  Several expressions for the $j$-th component $\left( x_{k}\right)_{j}$ of the
$k$-th eigenvector $x_{k}$ of a symmetric matrix $A$ belonging to eigenvalue
$\lambda_{k}$ and normalized as $x_{k}^{T}x_{k}=1$ are presented. In
particular, the expression \[ \left(
x_{k}\right)_{j}^{2}=-\frac{1}{c_{A}^{\prime}\left( \lambda_{k}\right)
}\det\left( A_{\backslash\left\{ j\right\} }-\lambda_{k}I\right) \] where
$c_{A}\left( \lambda\right) =\det\left( A-\lambda I\right) $ is the
characteristic polynomial of $A$, $c_{A}^{\prime}\left( \lambda\right)
=\frac{dc_{A}\left( \lambda\right) }{d\lambda}$ and $A_{\backslash\left\{
j\right\} }$ is obtained from $A$ by removal of row $j$ and column $j$,
suggests us to consider the square eigenvector component as a graph centrality
metric for node $j$ that reflects the impact of the removal of node $j$ from
the graph at an eigenfrequency/eigenvalue $\lambda_{k}$ of a graph related
matrix (such as the adjacency or Laplacian matrix). Removal of nodes in a graph
relates to the robustness of a graph. The set of such nodal centrality metrics,
the squared eigenvector components $\left( x_{k}\right)_{j}^{2}$ of the
adjacency matrix over all eigenvalue $\lambda_{k}$ for each node $j$, is
'ideal' in the sense of being complete, \emph{almost} uncorrelated and
mathematically precisely defined and computable. Fundamental weights (column
sum of $X$) and dual fundamental weights (row sum of $X$) are introduced as
spectral metrics that condense information embedded in the orthogonal
eigenvector matrix $X$, with elements $X_{ij}=\left( x_{j}\right)_{i}$.
  In addition to the criterion {\em If the algebraic connectivity is positive,
then the graph is connected}, we found an alternative condition: {\em If
$\min_{1\leq k\leq N}\left( \lambda_{k}^{2}(A)\right) =d_{\min}$, then the
graph is disconnected.}

categories: math.SP cond-mat.stat-mech cs.DM cs.SI physics.soc-ph


title:
Non-equilibrium noise in the (non-)Abelian fractional quantum Hall
  effect

abstract:
  We analyse the noise of the edge current of a generic fractional quantum Hall
state in a tunnelling point contact system. We show that the non-symmetrized
noise in the edge current for the system out-of-equilibrium is completely
determined by the noise in the tunnelling current and the Nyquist-Johnson
(equilibrium) noise of the edge current. Simply put, the noise in the
tunnelling current does not simply add up the equilibrium noise of the edge
current. A correction term arises associated with the correlation between the
tunnelling current and the edge current. We show, using a non-equilibrium Ward
identity, that this correction term is determined by the anti-symmetric part of
the noise in the tunnelling current. This leads to a non-equilibrium
fluctuation-dissipation theorem and related expressions for the excess and shot
noise of the noise in the edge current. Our approach makes use of simple
properties of the edge, such as charge conservation and chirality, and applies
to generic constructions of the edge theory which includes edges of non-Abelian
states and edges with multiple charged channels. Two important tools we make
use of are the non-equilibrium Kubo formula and the non-equilibrium Ward
identity. We discuss these identities in the appendix.


title:
Multidisciplinary Engineering Models: Methodology and Case Study in
  Spreadsheet Analytics

abstract:
  This paper demonstrates a methodology to help practitioners maximise the
utility of complex multidisciplinary engineering models implemented as
spreadsheets, an area presenting unique challenges. As motivation we
investigate the expanding use of Integrated Resource Management(IRM) models
which assess the sustainability of urban masterplan designs. IRM models reflect
the inherent complexity of multidisciplinary sustainability analysis by
integrating models from many disciplines. This complexity makes their use
time-consuming and reduces their adoption.
  We present a methodology and toolkit for analysing multidisciplinary
engineering models implemented as spreadsheets to alleviate such problems and
increase their adoption. For a given output a relevant slice of the model is
extracted, visualised and analysed by computing model and interdisciplinary
metrics. A sensitivity analysis of the extracted model supports engineers in
their optimisation efforts. These methods expose, manage and reduce model
complexity and risk whilst giving practitioners insight into multidisciplinary
model composition. We report application of the methodology to several
generations of an industrial IRM model and detail the insight generated,
particularly considering model evolution.


title:
Do we have unitary and (super)renormalizable Quantum Gravity below
  Planck scale?

abstract:
  We explore how the stability of metric perturbations in higher derivative
theories of gravity depends on the energy scale of initial seeds of such
perturbations and on a typical energy scale of the gravitational vacuum
background. It is shown that, at least in the cases of specific cosmological
backgrounds, that the unphysical massive ghost which is present in the spectrum
of such theories is not growing up as a physical excitation and remains in the
vacuum state, until the initial frequency of the perturbation is close to the
Planck order of magnitude. In this situation the existing versions of
renormalizable and superrenormalizable theories can be seen as very
satisfactory effective theories of Quantum Gravity below the Planck scale.


title: Conductivity of epitaxial and CVD graphene with correlated line defects

abstract:
  Transport properties of single-layer graphene with correlated one-dimensional
defects are studied using the time-dependent real-space Kubo-Greenwood
formalism. Such defects are present in epitaxial graphene, comprising atomic
terraces and steps due to the substrate morphology, and in polycrystalline
chemically-vapor-deposited (CVD) graphene due to the grain boundaries, composed
of a periodic array of dislocations, or quasi-periodic nanoripples originated
from the metal substrate. The extended line defects are described by the
long-range Lorentzian-type scattering potential. The dc conductivity is
calculated numerically for different cases of distribution of line defects.
This includes a random (uncorrelated) and a correlated distribution with a
prevailing direction in the orientation of lines. The anisotropy of the
conductivity along and across the line defects is revealed, which agrees with
experimental measurements for epitaxial graphene grown on SiC. We performed a
detailed study of the conductivity for different defect correlations,
introducing the correlation angle alpha_max (i.e. the maximum possible angle
between any two lines). We find that for a given electron density, the relative
enhancement of the conductivity for the case of fully correlated line defects
in comparison to the case of uncorrelated ones is larger for a higher defect
density. Finally, we study the conductivity of realistic samples where both
extended line defects as well as point-like scatterers such as adatoms and
charged impurities are presented.


title: Arrow's Theorem by Arrow Theory

abstract:
  We give a categorical account of Arrow's theorem, a seminal result in social
choice theory.


title:
Spontaneous R-parity violation in the minimal gauged $(B-L)$
  supersymmetry with a $125\;{\rm GeV}$ Higgs

abstract:
  We precisely derive the mass squared matrices for charged and neutral (CP-odd
and CP-even) Higgs, as well as the mass matrices for neutrino-neutralino and
charged lepton-chargino in the minimal R-parity violating supersymmetry with
local $U(1)_{B-L}$ symmetry. In the framework the nonzero TeV scale vacuum
expectations of right-handed sneutrinos induce the heavy mass of neutral
$U(1)_{B-L}$ gauge boson, and result in relatively large mixing between the
lightest CP-even Higgs and three generation right-handed sneutrinos when we
include the one-loop corrections to the scalar potential. We numerically show
that there is parameter space of the considered model to accommodate
experimental data on the newly ones of Higgs signal from LHC and experimental
observations on the neutrino oscillation simultaneously.


title:
Giant modification of atomic transitions probabilities induced by
  magnetic field: forbidden transitions become predominant

abstract:
  Magnetic field-induced giant modification of probabilities for seven
components of 6S1/2 (Fg=3) - 6P3/2 (Fe=5) transition of Cs D2 line forbidden by
selection rules is observed experimentally for the first time. For the case of
excitation with circularly-polarized laser radiation, the probability of
Fg=3,mF=-3 - Fe=5,mF=-2 transition becomes the largest among 25 transitions of
Fg=3 - Fe=2,3,4,5 group in a wide range of magnetic field 200 - 3200 G.
Moreover, the modification is the largest among D2 lines of alkali metals. A
half-wave-thick cell (length along the beam propagation axis L=426 nm) filled
with Cs has been used in order to achieve sub-Doppler resolution which allows
for separating the large number of atomic transitions that appear in the
absorption spectrum when an external magnetic field is applied. For B > 3 kG
the group of seven transitions Fg=3 - Fe=5 is completely resolved and is
located at the high frequency wing of Fg=3 - Fe=2,3,4 transitions. The applied
theoretical model very well describes the experimental curves.


title: Semitransparent One Dimensional Potential, A Green's Function Approach

abstract:
  We study the unstable harmonic oscillator and the unstable linear potential
in the presence of the point potential, which is the superposition of the Dirac
$\delta(x)$ and the derivative $\delta'(x)$. Using the \textit{physical}
boundary conditions for the Green's function we derive for both systems the
resonance poles and the resonance wave functions. The matching conditions for
the resonance wave functions coincide with those obtained by the self-adjoint
extensions of the point potentials and also by the modelling of the
$\delta'(x)$. We find that, with our definitions, the pure $b\delta'(x)$
barrier is semi-transparent \textit{independent} of the value of $b$.


title:
miRNA and Gene Expression based Cancer Classification using Self-
  Learning and Co-Training Approaches

abstract:
  miRNA and gene expression profiles have been proved useful for classifying
cancer samples. Efficient classifiers have been recently sought and developed.
A number of attempts to classify cancer samples using miRNA/gene expression
profiles are known in literature. However, the use of semi-supervised learning
models have been used recently in bioinformatics, to exploit the huge corpuses
of publicly available sets. Using both labeled and unlabeled sets to train
sample classifiers, have not been previously considered when gene and miRNA
expression sets are used. Moreover, there is a motivation to integrate both
miRNA and gene expression for a semi-supervised cancer classification as that
provides more information on the characteristics of cancer samples. In this
paper, two semi-supervised machine learning approaches, namely self-learning
and co-training, are adapted to enhance the quality of cancer sample
classification. These approaches exploit the huge public corpuses to enrich the
training data. In self-learning, miRNA and gene based classifiers are enhanced
independently. While in co-training, both miRNA and gene expression profiles
are used simultaneously to provide different views of cancer samples. To our
knowledge, it is the first attempt to apply these learning approaches to cancer
classification. The approaches were evaluated using breast cancer,
hepatocellular carcinoma (HCC) and lung cancer expression sets. Results show up
to 20% improvement in F1-measure over Random Forests and SVM classifiers.
Co-Training also outperforms Low Density Separation (LDS) approach by around
25% improvement in F1-measure in breast cancer.


title:
Combining Evaluation Metrics via the Unanimous Improvement Ratio and its
  Application to Clustering Tasks

abstract:
  Many Artificial Intelligence tasks cannot be evaluated with a single quality
criterion and some sort of weighted combination is needed to provide system
rankings. A problem of weighted combination measures is that slight changes in
the relative weights may produce substantial changes in the system rankings.
This paper introduces the Unanimous Improvement Ratio (UIR), a measure that
complements standard metric combination criteria (such as van Rijsbergen's
F-measure) and indicates how robust the measured differences are to changes in
the relative weights of the individual metrics. UIR is meant to elucidate
whether a perceived difference between two systems is an artifact of how
individual metrics are weighted.
  Besides discussing the theoretical foundations of UIR, this paper presents
empirical results that confirm the validity and usefulness of the metric for
the Text Clustering problem, where there is a tradeoff between precision and
recall based metrics and results are particularly sensitive to the weighting
scheme used to combine them. Remarkably, our experiments show that UIR can be
used as a predictor of how well differences between systems measured on a given
test bed will also hold in a different test bed.


title:
Computing Approximate Nash Equilibria and Robust Best-Responses Using
  Sampling

abstract:
  This article discusses two contributions to decision-making in complex
partially observable stochastic games. First, we apply two state-of-the-art
search techniques that use Monte-Carlo sampling to the task of approximating a
Nash-Equilibrium (NE) in such games, namely Monte-Carlo Tree Search (MCTS) and
Monte-Carlo Counterfactual Regret Minimization (MCCFR). MCTS has been proven to
approximate a NE in perfect-information games. We show that the algorithm
quickly finds a reasonably strong strategy (but not a NE) in a complex
imperfect information game, i.e. Poker. MCCFR on the other hand has theoretical
NE convergence guarantees in such a game. We apply MCCFR for the first time in
Poker. Based on our experiments, we may conclude that MCTS is a valid approach
if one wants to learn reasonably strong strategies fast, whereas MCCFR is the
better choice if the quality of the strategy is most important. Our second
contribution relates to the observation that a NE is not a best response
against players that are not playing a NE. We present Monte-Carlo Restricted
Nash Response (MCRNR), a sample-based algorithm for the computation of
restricted Nash strategies. These are robust best-response strategies that (1)
exploit non-NE opponents more than playing a NE and (2) are not (overly)
exploitable by other strategies. We combine the advantages of two
state-of-the-art algorithms, i.e. MCCFR and Restricted Nash Response (RNR).
MCRNR samples only relevant parts of the game tree. We show that MCRNR learns
quicker than standard RNR in smaller games. Also we show in Poker that MCRNR
learns robust best-response strategies fast, and that these strategies exploit
opponents more than playing a NE does.


title: Proximity-Based Non-uniform Abstractions for Approximate Planning

abstract:
  In a deterministic world, a planning agent can be certain of the consequences
of its planned sequence of actions. Not so, however, in dynamic, stochastic
domains where Markov decision processes are commonly used. Unfortunately these
suffer from the curse of dimensionality: if the state space is a Cartesian
product of many small sets (dimensions), planning is exponential in the number
of those dimensions.
  Our new technique exploits the intuitive strategy of selectively ignoring
various dimensions in different parts of the state space. The resulting
non-uniformity has strong implications, since the approximation is no longer
Markovian, requiring the use of a modified planner. We also use a spatial and
temporal proximity measure, which responds to continued planning as well as
movement of the agent through the state space, to dynamically adapt the
abstraction as planning progresses.
  We present qualitative and quantitative results across a range of
experimental domains showing that an agent exploiting this novel approximation
method successfully finds solutions to the planning problem using much less
than the full state space. We assess and analyse the features of domains which
our method can exploit.


title: Location-Based Reasoning about Complex Multi-Agent Behavior

abstract:
  Recent research has shown that surprisingly rich models of human activity can
be learned from GPS (positional) data. However, most effort to date has
concentrated on modeling single individuals or statistical properties of groups
of people. Moreover, prior work focused solely on modeling actual successful
executions (and not failed or attempted executions) of the activities of
interest. We, in contrast, take on the task of understanding human
interactions, attempted interactions, and intentions from noisy sensor data in
a fully relational multi-agent setting. We use a real-world game of capture the
flag to illustrate our approach in a well-defined domain that involves many
distinct cooperative and competitive joint activities. We model the domain
using Markov logic, a statistical-relational language, and learn a theory that
jointly denoises the data and infers occurrences of high-level activities, such
as a player capturing an enemy. Our unified model combines constraints imposed
by the geometry of the game area, the motion model of the players, and by the
rules and dynamics of the game in a probabilistically and logically sound
fashion. We show that while it may be impossible to directly detect a
multi-agent activity due to sensor noise or malfunction, the occurrence of the
activity can still be inferred by considering both its impact on the future
behaviors of the people involved as well as the events that could have preceded
it. Further, we show that given a model of successfully performed multi-agent
activities, along with a set of examples of failed attempts at the same
activities, our system automatically learns an augmented model that is capable
of recognizing success and failure, as well as goals of peoples actions with
high accuracy. We compare our approach with other alternatives and show that
our unified model, which takes into account not only relationships among
individual players, but also relationships among activities over the entire
length of a game, although more computationally costly, is significantly more
accurate. Finally, we demonstrate that explicitly modeling unsuccessful
attempts boosts performance on other important recognition tasks.


title: A discrete uniformization theorem for polyhedral surfaces II

abstract:
  A discrete conformality for hyperbolic polyhedral surfaces is introduced in
this paper. This discrete conformality is shown to be computable. It is proved
that each hyperbolic polyhedral metric on a closed surface is discrete
conformal to a unique hyperbolic polyhedral metric with a given discrete
curvature satisfying Gauss-Bonnet formula. Furthermore, the hyperbolic
polyhedral metric with given curvature can be obtained using a discrete Yamabe
flow with surgery. In particular, each hyperbolic polyhedral metric on a closed
surface with negative Euler characteristic is discrete conformal to a unique
hyperbolic metric.


title: Robust Local Search for Solving RCPSP/max with Durational Uncertainty

abstract:
  Scheduling problems in manufacturing, logistics and project management have
frequently been modeled using the framework of Resource Constrained Project
Scheduling Problems with minimum and maximum time lags (RCPSP/max). Due to the
importance of these problems, providing scalable solution schedules for
RCPSP/max problems is a topic of extensive research. However, all existing
methods for solving RCPSP/max assume that durations of activities are known
with certainty, an assumption that does not hold in real world scheduling
problems where unexpected external events such as manpower availability,
weather changes, etc. lead to delays or advances in completion of activities.
Thus, in this paper, our focus is on providing a scalable method for solving
RCPSP/max problems with durational uncertainty. To that end, we introduce the
robust local search method consisting of three key ideas: (a) Introducing and
studying the properties of two decision rule approximations used to compute
start times of activities with respect to dynamic realizations of the
durational uncertainty; (b) Deriving the expression for robust makespan of an
execution strategy based on decision rule approximations; and (c) A robust
local search mechanism to efficiently compute activity execution strategies
that are robust against durational uncertainty. Furthermore, we also provide
enhancements to local search that exploit temporal dependencies between
activities. Our experimental results illustrate that robust local search is
able to provide robust execution strategies efficiently.


title:
Unfounded Sets and Well-Founded Semantics of Answer Set Programs with
  Aggregates

abstract:
  Logic programs with aggregates (LPA) are one of the major linguistic
extensions to Logic Programming (LP). In this work, we propose a generalization
of the notions of unfounded set and well-founded semantics for programs with
monotone and antimonotone aggregates (LPAma programs). In particular, we
present a new notion of unfounded set for LPAma programs, which is a sound
generalization of the original definition for standard (aggregate-free) LP. On
this basis, we define a well-founded operator for LPAma programs, the fixpoint
of which is called well-founded model (or well-founded semantics) for LPAma
programs. The most important properties of unfounded sets and the well-founded
semantics for standard LP are retained by this generalization, notably
existence and uniqueness of the well-founded model, together with a strong
relationship to the answer set semantics for LPAma programs. We show that one
of the D-well-founded semantics, defined by Pelov, Denecker, and Bruynooghe for
a broader class of aggregates using approximating operators, coincides with the
well-founded model as defined in this work on LPAma programs. We also discuss
some complexity issues, most importantly we give a formal proof of tractable
computation of the well-founded model for LPA programs. Moreover, we prove that
for general LPA programs, which may contain aggregates that are neither
monotone nor antimonotone, deciding satisfaction of aggregate expressions with
respect to partial interpretations is coNP-complete. As a consequence, a
well-founded semantics for general LPA programs that allows for tractable
computation is unlikely to exist, which justifies the restriction on LPAma
programs. Finally, we present a prototype system extending DLV, which supports
the well-founded semantics for LPAma programs, at the time of writing the only
implemented system that does so. Experiments with this prototype show
significant computational advantages of aggregate constructs over equivalent
aggregate-free encodings.


title: Dr.Fill: Crosswords and an Implemented Solver for Singly Weighted CSPs

abstract:
  We describe Dr.Fill, a program that solves American-style crossword puzzles.
From a technical perspective, Dr.Fill works by converting crosswords to
weighted CSPs, and then using a variety of novel techniques to find a solution.
These techniques include generally applicable heuristics for variable and value
selection, a variant of limited discrepancy search, and postprocessing and
partitioning ideas. Branch and bound is not used, as it was incompatible with
postprocessing and was determined experimentally to be of little practical
value. Dr.Fillls performance on crosswords from the American Crossword Puzzle
Tournament suggests that it ranks among the top fifty or so crossword solvers
in the world.


title: SAS+ Planning as Satisfiability

abstract:
  Planning as satisfiability is a principal approach to planning with many
eminent advantages. The existing planning as satisfiability techniques usually
use encodings compiled from STRIPS. We introduce a novel SAT encoding scheme
(SASE) based on the SAS+ formalism. The new scheme exploits the structural
information in SAS+, resulting in an encoding that is both more compact and
efficient for planning. We prove the correctness of the new encoding by
establishing an isomorphism between the solution plans of SASE and that of
STRIPS based encodings. We further analyze the transition variables newly
introduced in SASE to explain why it accommodates modern SAT solving algorithms
and improves performance. We give empirical statistical results to support our
analysis. We also develop a number of techniques to further reduce the encoding
size of SASE, and conduct experimental studies to show the strength of each
individual technique. Finally, we report extensive experimental results to
demonstrate significant improvements of SASE over the state-of-the-art STRIPS
based encoding schemes in terms of both time and memory efficiency.


title:
Learning and Reasoning with Action-Related Places for Robust Mobile
  Manipulation

abstract:
  We propose the concept of Action-Related Place (ARPlace) as a powerful and
flexible representation of task-related place in the context of mobile
manipulation. ARPlace represents robot base locations not as a single position,
but rather as a collection of positions, each with an associated probability
that the manipulation action will succeed when located there. ARPlaces are
generated using a predictive model that is acquired through experience-based
learning, and take into account the uncertainty the robot has about its own
location and the location of the object to be manipulated.
  When executing the task, rather than choosing one specific goal position
based only on the initial knowledge about the task context, the robot
instantiates an ARPlace, and bases its decisions on this ARPlace, which is
updated as new information about the task becomes available. To show the
advantages of this least-commitment approach, we present a transformational
planner that reasons about ARPlaces in order to optimize symbolic plans. Our
empirical evaluation demonstrates that using ARPlaces leads to more robust and
efficient mobile manipulation in the face of state estimation uncertainty on
our simulated robot.


title:
Exploiting Model Equivalences for Solving Interactive Dynamic Influence
  Diagrams

abstract:
  We focus on the problem of sequential decision making in partially observable
environments shared with other agents of uncertain types having similar or
conflicting objectives. This problem has been previously formalized by multiple
frameworks one of which is the interactive dynamic influence diagram (I-DID),
which generalizes the well-known influence diagram to the multiagent setting.
I-DIDs are graphical models and may be used to compute the policy of an agent
given its belief over the physical state and others models, which changes as
the agent acts and observes in the multiagent setting.
  As we may expect, solving I-DIDs is computationally hard. This is
predominantly due to the large space of candidate models ascribed to the other
agents and its exponential growth over time. We present two methods for
reducing the size of the model space and stemming its exponential growth. Both
these methods involve aggregating individual models into equivalence classes.
Our first method groups together behaviorally equivalent models and selects
only those models for updating which will result in predictive behaviors that
are distinct from others in the updated model space. The second method further
compacts the model space by focusing on portions of the behavioral predictions.
Specifically, we cluster actionally equivalent models that prescribe identical
actions at a single time step. Exactly identifying the equivalences would
require us to solve all models in the initial set. We avoid this by selectively
solving some of the models, thereby introducing an approximation. We discuss
the error introduced by the approximation, and empirically demonstrate the
improved efficiency in solving I-DIDs due to the equivalences.


title:
Counting-Based Search: Branching Heuristics for Constraint Satisfaction
  Problems

abstract:
  Designing a search heuristic for constraint programming that is reliable
across problem domains has been an important research topic in recent years.
This paper concentrates on one family of candidates: counting-based search.
Such heuristics seek to make branching decisions that preserve most of the
solutions by determining what proportion of solutions to each individual
constraint agree with that decision. Whereas most generic search heuristics in
constraint programming rely on local information at the level of the individual
variable, our search heuristics are based on more global information at the
constraint level. We design several algorithms that are used to count the
number of solutions to specific families of constraints and propose some search
heuristics exploiting such information. The experimental part of the paper
considers eight problem domains ranging from well-established benchmark puzzles
to rostering and sport scheduling. An initial empirical analysis identifies
heuristic maxSD as a robust candidate among our proposals.eWe then evaluate the
latter against the state of the art, including the latest generic search
heuristics, restarts, and discrepancy-based tree traversals. Experimental
results show that counting-based search generally outperforms other generic
heuristics.


title: Cloning in Elections: Finding the Possible Winners

abstract:
  We consider the problem of manipulating elections by cloning candidates. In
our model, a manipulator can replace each candidate c by several clones, i.e.,
new candidates that are so similar to c that each voter simply replaces c in
his vote with a block of these new candidates, ranked consecutively. The
outcome of the resulting election may then depend on the number of clones as
well as on how each voter orders the clones within the block. We formalize what
it means for a cloning manipulation to be successful (which turns out to be a
surprisingly delicate issue), and, for a number of common voting rules,
characterize the preference profiles for which a successful cloning
manipulation exists. We also consider the model where there is a cost
associated with producing each clone, and study the complexity of finding a
minimum-cost cloning manipulation. Finally, we compare cloning with two related
problems: the problem of control by adding candidates and the problem of
possible (co)winners when new alternatives can join.


title:
Semantic Similarity Measures Applied to an Ontology for Human-Like
  Interaction

abstract:
  The focus of this paper is the calculation of similarity between two concepts
from an ontology for a Human-Like Interaction system. In order to facilitate
this calculation, a similarity function is proposed based on five dimensions
(sort, compositional, essential, restrictive and descriptive) constituting the
structure of ontological knowledge. The paper includes a proposal for computing
a similarity function for each dimension of knowledge. Later on, the similarity
values obtained are weighted and aggregated to obtain a global similarity
measure. In order to calculate those weights associated to each dimension, four
training methods have been proposed. The training methods differ in the element
to fit: the user, concepts or pairs of concepts, and a hybrid approach. For
evaluating the proposal, the knowledge base was fed from WordNet and extended
by using a knowledge editing toolkit (Cognos). The evaluation of the proposal
is carried out through the comparison of system responses with those given by
human test subjects, both providing a measure of the soundness of the procedure
and revealing ways in which the proposal may be improved.


title:
Completeness Guarantees for Incomplete Ontology Reasoners: Theory and
  Practice

abstract:
  To achieve scalability of query answering, the developers of Semantic Web
applications are often forced to use incomplete OWL 2 reasoners, which fail to
derive all answers for at least one query, ontology, and data set. The lack of
completeness guarantees, however, may be unacceptable for applications in areas
such as health care and defence, where missing answers can adversely affect the
applications functionality. Furthermore, even if an application can tolerate
some level of incompleteness, it is often advantageous to estimate how many and
what kind of answers are being lost.
  In this paper, we present a novel logic-based framework that allows one to
check whether a reasoner is complete for a given query Q and ontology T---that
is, whether the reasoner is guaranteed to compute all answers to Q w.r.t. T and
an arbitrary data set A. Since ontologies and typical queries are often fixed
at application design time, our approach allows application developers to check
whether a reasoner known to be incomplete in general is actually complete for
the kinds of input relevant for the application.
  We also present a technique that, given a query Q, an ontology T, and
reasoners R_1 and R_2 that satisfy certain assumptions, can be used to
determine whether, for each data set A, reasoner R_1 computes more answers to Q
w.r.t. T and A than reasoner R_2. This allows application developers to select
the reasoner that provides the highest degree of completeness for Q and T that
is compatible with the applications scalability requirements.
  Our results thus provide a theoretical and practical foundation for the
design of future ontology-based information systems that maximise scalability
while minimising or even eliminating incompleteness of query answers.


title:
Consistency Techniques for Flow-Based Projection-Safe Global Cost
  Functions in Weighted Constraint Satisfaction

abstract:
  Many combinatorial problems deal with preferences and violations, the goal of
which is to find solutions with the minimum cost. Weighted constraint
satisfaction is a framework for modeling such problems, which consists of a set
of cost functions to measure the degree of violation or preferences of
different combinations of variable assignments. Typical solution methods for
weighted constraint satisfaction problems (WCSPs) are based on branch-and-bound
search, which are made practical through the use of powerful consistency
techniques such as AC*, FDAC*, EDAC* to deduce hidden cost information and
value pruning during search. These techniques, however, are designed to be
efficient only on binary and ternary cost functions which are represented in
table form. In tackling many real-life problems, high arity (or global) cost
functions are required. We investigate efficient representation scheme and
algorithms to bring the benefits of the consistency techniques to also high
arity cost functions, which are often derived from hard global constraints from
classical constraint satisfaction. The literature suggests some global cost
functions can be represented as flow networks, and the minimum cost flow
algorithm can be used to compute the minimum costs of such networks in
polynomial time. We show that naive adoption of this flow-based algorithmic
method for global cost functions can result in a stronger form of null-inverse
consistency. We further show how the method can be modified to handle cost
projections and extensions to maintain generalized versions of AC* and FDAC*
for cost functions with more than two variables. Similar generalization for the
stronger EDAC* is less straightforward. We reveal the oscillation problem when
enforcing EDAC* on cost functions sharing more than one variable. To avoid
oscillation, we propose a weak version of EDAC* and generalize it to weak
EDGAC* for non-binary cost functions. Using various benchmarks involving the
soft variants of hard global constraints ALLDIFFERENT, GCC, SAME, and REGULAR,
empirical results demonstrate that our proposal gives improvements of up to an
order of magnitude when compared with the traditional constraint optimization
approach, both in terms of time and pruning.


title: Drake: An Efficient Executive for Temporal Plans with Choice

abstract:
  This work presents Drake, a dynamic executive for temporal plans with choice.
Dynamic plan execution strategies allow an autonomous agent to react quickly to
unfolding events, improving the robustness of the agent. Prior work developed
methods for dynamically dispatching Simple Temporal Networks, and further
research enriched the expressiveness of the plans executives could handle,
including discrete choices, which are the focus of this work. However, in some
approaches to date, these additional choices induce significant storage or
latency requirements to make flexible execution possible.
  Drake is designed to leverage the low latency made possible by a
preprocessing step called compilation, while avoiding high memory costs through
a compact representation. We leverage the concepts of labels and environments,
taken from prior work in Assumption-based Truth Maintenance Systems (ATMS), to
concisely record the implications of the discrete choices, exploiting the
structure of the plan to avoid redundant reasoning or storage. Our labeling and
maintenance scheme, called the Labeled Value Set Maintenance System, is
distinguished by its focus on properties fundamental to temporal problems, and,
more generally, weighted graph algorithms. In particular, the maintenance
system focuses on maintaining a minimal representation of non-dominated
constraints. We benchmark Drakes performance on random structured problems, and
find that Drake reduces the size of the compiled representation by a factor of
over 500 for large problems, while incurring only a modest increase in run-time
latency, compared to prior work in compiled executives for temporal plans with
discrete choices.


title:
Reformulating the Situation Calculus and the Event Calculus in the
  General Theory of Stable Models and in Answer Set Programming

abstract:
  Circumscription and logic programs under the stable model semantics are two
well-known nonmonotonic formalisms. The former has served as a basis of
classical logic based action formalisms, such as the situation calculus, the
event calculus and temporal action logics; the latter has served as a basis of
a family of action languages, such as language A and several of its
descendants. Based on the discovery that circumscription and the stable model
semantics coincide on a class of canonical formulas, we reformulate the
situation calculus and the event calculus in the general theory of stable
models. We also present a translation that turns the reformulations further
into answer set programs, so that efficient answer set solvers can be applied
to compute the situation calculus and the event calculus.


title:
Thermo-electromechanical effects in relaxed shape graphene and
  bandstructures of graphene quantum dots

abstract:
  We investigate the in-plane oscillations of the relaxed shape graphene due to
externally applied tensile edge stress along both the armchair and zigzag
directions. We show that the total elastic energy density is enhanced with
temperature for the case of applied tensile edge stress along the zigzag
direction. Thermo-electromechanical effects are treated via pseudomorphic
vector potentials to analyze the influence of these coupled effects on the
bandstructures of bilayer graphene quantum dots (QDs). We report that the level
crossing between ground and first excited states in the localized edge states
can be achieved with the accessible values of temperature. In particular, the
level crossing point extends to higher temperatures with decreasing values of
externally applied tensile edge stress along the armchair direction. This kind
of level crossings is absent in the states formed at the center of the graphene
sheet due to the presence of three fold symmetry.


title: Computing All-Pairs Shortest Paths by Leveraging Low Treewidth

abstract:
  We present two new and efficient algorithms for computing all-pairs shortest
paths. The algorithms operate on directed graphs with real (possibly negative)
weights. They make use of directed path consistency along a vertex ordering d.
Both algorithms run in O(n^2 w_d) time, where w_d is the graph width induced by
this vertex ordering. For graphs of constant treewidth, this yields O(n^2)
time, which is optimal. On chordal graphs, the algorithms run in O(nm) time. In
addition, we present a variant that exploits graph separators to arrive at a
run time of O(n w_d^2 + n^2 s_d) on general graphs, where s_d andlt= w_d is the
size of the largest minimal separator induced by the vertex ordering d. We show
empirically that on both constructed and realistic benchmarks, in many cases
the algorithms outperform Floyd-Warshalls as well as Johnsons algorithm, which
represent the current state of the art with a run time of O(n^3) and O(nm + n^2
log n), respectively. Our algorithms can be used for spatial and temporal
reasoning, such as for the Simple Temporal Problem, which underlines their
relevance to the planning and scheduling community.


title:
'Gas cushion' model and hydrodynamic boundary conditions for
  superhydrophobic textures

abstract:
  Superhydrophobic Cassie textures with trapped gas bubbles reduce drag, by
generating large effective slip, which is important for a variety of
applications that involve a manipulation of liquids at the small scale. Here we
discuss how the dissipation in the gas phase of textures modifies their
friction properties. We propose an operator method, which allows us the mapping
of the flow in the gas subphase to a local slip boundary condition at the
liquid/gas interface. The determined uniquely local slip length depends on the
viscosity contrast and underlying topography, and can be immediately used to
evaluate an effective slip of the texture. Besides superlubricating Cassie
surfaces our approach is valid for rough surfaces impregnated by a
low-viscosity 'lubricant', and even for Wenzel textures, where a liquid follows
the surface relief. These results provide a framework for the rational design
of textured surfaces for numerous applications.


title:
The contribution of the major planet search surveys to EChO target
  selection

abstract:
  The EChO core science will be based on a three tier survey, each with
increasing sensitivity, in order to study the population of exo-planets from
super-Earths to Jupiter-like planets, in the very hot to temperate zones
(temperatures of 300 K - 3000 K) of F to M-type host stars. To achieve a
meaningful outcome an accurate selection of the target sample is needed. In
this paper we analyse the targets, suitable for EChO observations, expected to
result from a sample of present and forthcoming detection surveys. Exoplanets
currently known are already sufficient to provide a large and diverse sample.
However we expect the results from these surveys to increase the sample of
smaller planets that will allow us to optimize the EChO sample selection.


title:
Modelling Observation Correlations for Active Exploration and Robust
  Object Detection

abstract:
  Today, mobile robots are expected to carry out increasingly complex tasks in
multifarious, real-world environments. Often, the tasks require a certain
semantic understanding of the workspace. Consider, for example, spoken
instructions from a human collaborator referring to objects of interest; the
robot must be able to accurately detect these objects to correctly understand
the instructions. However, existing object detection, while competent, is not
perfect. In particular, the performance of detection algorithms is commonly
sensitive to the position of the sensor relative to the objects in the scene.
This paper presents an online planning algorithm which learns an explicit model
of the spatial dependence of object detection and generates plans which
maximize the expected performance of the detection, and by extension the
overall plan performance. Crucially, the learned sensor model incorporates
spatial correlations between measurements, capturing the fact that successive
measurements taken at the same or nearby locations are not independent. We show
how this sensor model can be incorporated into an efficient forward search
algorithm in the information space of detected objects, allowing the robot to
generate motion plans efficiently. We investigate the performance of our
approach by addressing the tasks of door and text detection in indoor
environments and demonstrate significant improvement in detection performance
during task execution over alternative methods in simulated and real robot
experiments.


title: Local Consistency and SAT-Solvers

abstract:
  Local consistency techniques such as k-consistency are a key component of
specialised solvers for constraint satisfaction problems. In this paper we show
that the power of using k-consistency techniques on a constraint satisfaction
problem is precisely captured by using a particular inference rule, which we
call negative-hyper-resolution, on the standard direct encoding of the problem
into Boolean clauses. We also show that current clause-learning SAT-solvers
will discover in expected polynomial time any inconsistency that can be deduced
from a given set of clauses using negative-hyper-resolvents of a fixed size. We
combine these two results to show that, without being explicitly designed to do
so, current clause-learning SAT-solvers efficiently simulate k-consistency
techniques, for all fixed values of k. We then give some experimental results
to show that this feature allows clause-learning SAT-solvers to efficiently
solve certain families of constraint problems which are challenging for
conventional constraint-programming solvers.


title: Tail Asymptotics of Random Sum and Maximum of Log-Normal Risks

abstract:
  In this paper we derive the asymptotic behaviour of the survival function of
both random sum and random maximum of log-normal risks. As for the case of
finite sum and maximum investigated in Asmussen and Rojas-Nandaypa (2008) also
for the more general setup of random sums and random maximum the principle of a
single big jump holds. We investigate both the log-normal sequences and some
related dependence structures motivated by stationary Gaussian sequences.


title: Neutrino Oscillation from Hidden GRB Jets

abstract:
  Collapsars are the likely progenitors of Long Gamma-Ray Burst (lGRBs). lGRBs
have been observed to last for thousands to tens of thousands of seconds, thus
making unlikely the neutrino-driven engine as the main mechanism for driving
the jets. In this context, the Blandford-Znajek mechanism seems likely to
explain the production of rotational-axis directed jets without the need for
large accretion rates. These engines, require magnetic fields between $10^{12}$
G $< B < 10^{15}$ G threading the innerdisk, Kerr-BH region to exist. We derive
the neutrino self-energy and the effective potential up to O(1/$M_W^4$) in a
weakly and highly magnetized GRB fireball flow which is made up of electrons,
protons, neutrons and their anti-particles. We consider neutrino energies of
1-100 MeV which are produced during stellar collapse, merger events or in the
fireball itself by electron-positron annihilation, inverse beta decay and
nucleonic bremsstrahlung processes. Many of these neutrinos propagate through
the fireball and may oscillate resonantly. Using two-neutrino mixing we study
the possibility of these oscillations.


title:
Generalised friezes and a modified Caldero-Chapoton map depending on a
  rigid object, II

abstract:
  It is an important aspect of cluster theory that cluster categories are
"categorifications" of cluster algebras. This is expressed formally by the
(original) Caldero-Chapoton map X which sends certain objects of cluster
categories to elements of cluster algebras.
  Let \tau c --> b --> c be an Auslander-Reiten triangle. The map X has the
salient property that X(\tau c)X(c) - X(b) = 1. This is part of the definition
of a so-called frieze.
  The construction of X depends on a cluster tilting object. In a previous
paper, we introduced a modified Caldero-Chapoton map \rho depending on a rigid
object; these are more general than cluster tilting objects. The map \rho sends
objects of sufficiently nice triangulated categories to integers and has the
key property that \rho(\tau c)\rho(c) - \rho(b) is 0 or 1. This is part of the
definition of what we call a generalised frieze.
  Here we develop the theory further by constructing a modified
Caldero-Chapoton map, still depending on a rigid object, which sends objects of
sufficiently nice triangulated categories to elements of a commutative ring A.
We derive conditions under which the map is a generalised frieze, and show how
the conditions can be satisfied if A is a Laurent polynomial ring over the
integers.
  The new map is a proper generalisation of the maps X and \rho.


title:
Enhancement of Perpendicular Magnetic Anisotropy and Transmission of
  Spin-Hall-Effect-Induced Spin Currents by a Hf Spacer Layer in W/Hf/CoFeB/MgO
  Layer

abstract:
  We report that strong perpendicular magnetic anisotropy of the ferromagnetic
layer in a W/CoFeB/MgO multilayer structure can be established by inserting a
Hf layer as thin as 0.25 nm between the W and CoFeB layers. The Hf spacer also
allows transmission of spin currents generated by an in-plane charge current in
the W layer to apply strong spin torque on the CoFeB, thereby enabling
current-driven magnetic switching. The antidamping-like and field-like
components of the spin torque exerted on a 1 nm CoFeB layer are of comparable
magnitudes in this geometry. Both components originate from the spin Hall
effect in the underlying W layer.


title: An elementary approach to character sums over multiplicative subgroups

abstract:
  Let $p$ be an odd prime. Using I. M. Vinogradov's bilinear estimate, we
present an elementary approach to estimate nontrivially the character sum $$
\sum_{x\in H}\chi(x+a),\qquad a\in\Bbb F_p^*, $$ where $H<\Bbb F_p^*$ is a
multiplicative subgroup in finite prime field $\Bbb F_p$. Some interesting
mean-value estimates are also provided.


title: Probing Particle Physics from Top Down with Cosmic Strings

abstract:
  Making use of the wealth of new observational data coming from the sky it is
possible to constrain particle physics theories beyond the Standard Model. One
way to do this is illustrated in this article: a subset of theories admits
cosmic string solutions, topologically stable matter field configurations. In
these models, a network of cosmic strings inevitably forms in the early
universe and persists to the present time. The gravitational effects of these
strings leads to cosmological signatures which could be visible in current and
future data. The magnitude of these signatures increases as the energy scale of
the new physics involved in cosmic string formation increases. Thus, searching
for cosmological signatures of strings is a way to probe particle physics model
"from top down", as opposed to "from bottom up" as is done using data from
accelerators such as the Large Hadron Collider. Different ways of searching for
cosmic strings are illustrated in this article. They include Cosmic Microwave
Background temperature and polarization anisotropy maps, Large Scale Structure
optical and infrared surveys, and 21cm intensity maps.


title: A test-tube model for rainfall

abstract:
  If the temperature of a cell containing two partially miscible liquids is
changed very slowly, so that the miscibility is decreased, microscopic droplets
nucleate, grow and migrate to the interface due to their buoyancy. The system
may show an approximately periodic variation of the turbidity of the mixture,
as the mean droplet size fluctuates. These precipitation events are analogous
to rainfall from warm clouds. This paper considers a theoretical model for
these experiments. After nucleation the initial growth is by Ostwald ripening,
followed by a finite-time runaway growth of droplet sizes due to larger
droplets sweeping up smaller ones. The model predicts that the period $\Delta
t$ and the temperature sweep rate $\xi$ are related by $\Delta t\sim C
\xi^{-3/7}$, and is in good agreement with experiments. The coefficient $C$ has
a power-law divergence approaching the critical point of the miscibility
transition: $C\sim (T-T_{\rm c})^{-\eta}$, and the critical exponent $\eta$ is
determined.


title:
A Distributed Approach for the Optimal Power Flow Problem Based on ADMM
  and Sequential Convex Approximations

abstract:
  The optimal power flow (OPF) problem, which plays a central role in operating
electrical networks is considered. The problem is nonconvex and is in fact NP
hard. Therefore, designing efficient algorithms of practical relevance is
crucial, though their global optimality is not guaranteed. Existing
semi-definite programming relaxation based approaches are restricted to OPF
problems where zero duality holds. In this paper, an efficient novel method to
address the general nonconvex OPF problem is investigated. The proposed method
is based on alternating direction method of multipliers combined with
sequential convex approximations. The global OPF problem is decomposed into
smaller problems associated to each bus of the network, the solutions of which
are coordinated via a light communication protocol. Therefore, the proposed
method is highly scalable. The convergence properties of the proposed algorithm
are mathematically substantiated. Finally, the proposed algorithm is evaluated
on a number of test examples, where the convergence properties of the proposed
algorithm are numerically substantiated and the performance is compared with a
global optimal method.


title: Non-Commutative Resistance Networks

abstract:
  In the setting of finite-dimensional $C^*$-algebras ${\mathcal A}$ we define
what we call a Riemannian metric for ${\mathcal A}$, which when ${\mathcal A}$
is commutative is very closely related to a finite resistance network. We
explore the relationship with Dirichlet forms and corresponding seminorms that
are Markov and Leibniz, with corresponding matricial structure and metric on
the state space. We also examine associated Laplace and Dirac operators,
quotient energy seminorms, resistance distance, and the relationship with
standard deviation.


title: The magnitude of a graph

abstract:
  The magnitude of a graph is one of a family of cardinality-like invariants
extending across mathematics; it is a cousin to Euler characteristic and
geometric measure. Among its cardinality-like properties are multiplicativity
with respect to cartesian product and an inclusion-exclusion formula for the
magnitude of a union. Formally, the magnitude of a graph is both a rational
function over Q and a power series over Z. It shares features with one of the
most important of all graph invariants, the Tutte polynomial; for instance,
magnitude is invariant under Whitney twists when the points of identification
are adjacent. Nevertheless, the magnitude of a graph is not determined by its
Tutte polynomial, nor even by its cycle matroid, and it therefore carries
information that they do not.


title: Regularity of density for SDEs driven by degenerate L\'evy noises

abstract:
  By using Bismut's approach about the Malliavin calculus with jumps, we study
the regularity of the distributional density for SDEs driven by degenerate
additive L\'evy noises. Under full H\"ormander's conditions, we prove the
existence of distributional density and the weak continuity in the first
variable of the distributional density. Under the uniform first order Lie's
bracket condition, we also prove the smoothness of the density.


title: Commercialization of fuel cells: myth or reality?

abstract:
  Despite huge investment and efforts in the last decades, fuel cells are still
known as a fledgling industry after 170 years of the first fuel cell. It
becomes clear that these investment and efforts did not address the critical
questions. Why upscaling of fuel cells failed often when many researchers
stated their successes in small scale? Why the fuel cells with simpler
structure still lag far from the internal combustion (IC) engines and gas
turbines? Could the current investment of the hydrogen infrastructure reduce
substantially the fuel cell cost and make a breakthrough to the key issues of
durability, reliability and robustness? In this paper, we study these
fundamental questions and point out a must-way possible to reduce cost of fuel
cells and to substantially improve durability and reliability.


title: Tropicalizing the space of admissible covers

abstract:
  We study the relationship between tropical and classical Hurwitz moduli
spaces. Following recent work of Abramovich, Caporaso and Payne, we outline a
tropicalization for the moduli space of generalized Hurwitz covers of an
arbitrary genus curve. Our approach is to appeal to the geometry of admissible
covers, which compactify the Hurwitz scheme. We define and construct a moduli
space of tropical admissible covers, and study its relationship with the
skeleton of the Berkovich analytification of the classical space of admissible
covers. We use techniques from non-archimedean geometry to show that the
tropical and classical tautological maps are compatible via tropicalization,
and that the degree of the classical branch map can be recovered from the
tropical side. As a consequence, we obtain a proof, at the level of moduli
spaces, of the equality of classical and tropical Hurwitz numbers.


title: IR-conformal gauge theories and composite Higgs

abstract:
  The existence of non-trivial IR and UV fixed points in gauge theories as a
function of the number of fermion flavors and bare coupling is discussed in the
light of recent work. It is pointed out that in fact only a small subset of
potential IR-conformal gauge theories, i.e. theories whose IR behavior is
determined by an IR fixed point, has so far been examined. Recent lattice
computations of the spectrum in some cases where existence of an IR fixed point
is reasonably assured, however, reveal a non-QCD-like spectrum with the
lightest states being scalars. It is suggested that these naturally light
composite scalars provide a natural setting for the construction of new
composite Higgs models. A schematic outline of such a model is given.


title: Electronic nematic phase transition in the presence of anisotropy

abstract:
  We study the phase diagram of electronic nematic instability in the presence
of xy anisotropy. While a second order transition cannot occur in this case,
mean-field theory predicts that a first order transition occurs near van Hove
filling and its phase boundary forms a wing structure, which we term a
Griffiths wing, referring to his original work of He3-He4 mixtures. When
crossing the wing, the anisotropy of the electronic system exhibits a
discontinuous change, leading to a meta-nematic transition, i.e., the analog to
a meta-magnetic transition in a magnetic system. The upper edge of the wing
corresponds to a critical end line, which shows a non-monotonic temperature
dependence as a function of the external anisotropy and vanishes at a quantum
critical end point for a strong anisotropy. The mean-field phase diagram is,
however, very sensitive to fluctuations of the nematic order parameter,
yielding a topologically different phase diagram. The Griffiths wing is broken
into two pieces. A tiny wing appears close to zero anisotropy and the other is
realized for a strong anisotropy. Consequently three quantum critical end
points are realized. We discuss that these results can be related to various
materials including a cold atom system.


title:
HERMES: A Hierarchical Broadcast-Based Silicon Photonic Interconnect for
  Scalable Many-Core Systems

abstract:
  Optical interconnection networks, as enabled by recent advances in silicon
photonic device and fabrication technology, have the potential to address
on-chip and off-chip communication bottlenecks in many-core systems. Although
several designs have shown superior power efficiency and performance compared
to electrical alternatives, these networks will not scale to the thousands of
cores required in the future.
  In this paper, we introduce Hermes, a hybrid network composed of an optimized
broadcast for power-efficient low-latency global-scale coordination and
circuit-switch sub-networks for high-throughput data delivery. This network
will scale for use in thousand core chip systems. At the physical level,
SoI-based adiabatic coupler has been designed to provide low-loss and compact
optical power splitting. Based on the adiabatic coupler, a topology based on
2-ary folded butterfly is designed to provide linear power division in a
thousand core layout with minimal cross-overs. To address the network agility
and provide for efficient use of optical bandwidth, a flow control and routing
mechanism is introduced to dynamically allocate bandwidth and provide fairness
usage of network resources. At the system level, bloom filter-based filtering
for localization of communication are designed for reducing global traffic. In
addition, a novel greedy-based data and workload migration are leveraged to
increase the locality of communication in a NUCA (non-uniform cache access)
architecture. First order analytic evaluation results have indicated that
Hermes is scalable to at least 1024 cores and offers significant performance
improvement and power savings over prior silicon photonic designs.


title: Spectra of Cantor measures

abstract:
  Let $\mu_{q, b}$ be the Cantor measure associated with the iterated function
system $f_i(x)=x/b+i/q, 0\le i\le q-1$, where $2\le q, b/q\in \Z$. In this
paper, we consider spectra and maximal orthogonal sets of the Cantor measure
$\mu_{q, b}$ and their rational rescaling. We introduce a quantity to measure
level difference between a branch and its subbranch for the labeling tree
corresponding to a maximal orthogonal set of the Cantor measure $\mu_{q, b}$,
and use certain boundedness property of that quantity as sufficient and
necessary conditions for a maximal orthogonal set of the Cantor measure
$\mu_{q, b}$ to be its spectrum. We show that the integrally rescaled set
$K\Lambda$ is still a spectrum if it is a maximal orthogonal set, and we
provide a simple characterization for the integrally rescaled set to be a
maximal orthogonal set. As an application of the above characterization, we
find all integers $K$ such that $K\Lambda_4$ are spectra of the Cantor measure
$\mu_{2, 4}$, where $\Lambda_4:=\{\sum_{n=0}^\infty d_n 4^n: d_n\in \{0,
1\}\}\subset \Z$ is the first known spectrum for the Cantor measure $\mu_{2,
4}$. Finally we discuss rescaling spectra rationally and construct a spectrum
$\Lambda$ for the Cantor measure $\mu_{q, b}$ such that $\Lambda/(b-1)$ is a
maximal orthogonal set but not a spectrum.


title: On Weyl Groups and Artin Groups Associated to Orbifold Projective Lines

abstract:
  We associate a generalized root system in the sense of Kyoji Saito to an
orbifold projective line via the derived category of finite dimensional
representations of a certain bound quiver algebra. We generalize results by
Saito--Takebayshi and Yamada for elliptic Weyl groups and elliptic Artin groups
to the Weyl groups and the fundamental groups of the regular orbit spaces
associated to the generalized root systems. Moreover we study the relation
between this fundamental group and a certain subgroup of the autoequivalence
group of a triangulated subcategory of the derived category of $2$-Calabi--Yau
completion of the bound quiver algebra.


title:
Critical phenomena in the majority voter model on two dimensional
  regular lattices

abstract:
  In this work we studied the critical behavior of the critical point as
function of the number of nearest neighbors on two dimensional regular
lattices. We performed numerical simulations on triangular, hexagonal and
bilayer square lattices. Using standard finite size scaling theory we found
that all cases fall in the two dimensional Ising model universality class, but
that the critical point value for the bilayer lattice does not follow the
regular tendency that the Ising model shows.


title: Efficient Codes for Adversarial Wiretap Channels

abstract:
  In [13] we proposed a ({\rho}_r , {\rho}_w )-adversarial wiretap channel
model (AWTP) in which the adversary can adaptively choose to see a fraction
{\rho}_r of the codeword sent over the channel, and modify a fraction {\rho}_w
of the codeword by adding arbitrary noise values to them. In this paper we give
the first efficient construction of a capacity achieving code family that
provides perfect secrecy for this channel.


title: The Capacity of String-Replication Systems

abstract:
  It is known that the majority of the human genome consists of repeated
sequences. Furthermore, it is believed that a significant part of the rest of
the genome also originated from repeated sequences and has mutated to its
current form. In this paper, we investigate the possibility of constructing an
exponentially large number of sequences from a short initial sequence and
simple replication rules, including those resembling genomic replication
processes. In other words, our goal is to find out the capacity, or the
expressive power, of these string-replication systems. Our results include
exact capacities, and bounds on the capacities, of four fundamental
string-replication systems.


title:
On the correspondence between mirror-twisted sectors for N=2
  supersymmetric vertex operator superalgebras of the form $V \otimes V$ and
  N=1 Ramond sectors of $V$

abstract:
  Using recent results of the author along with Vander Werf, we present the
classification and construction of mirror-twisted modules for N=2
supersymmetric vertex operator superalgebras of the form $V \otimes V$ for the
signed transposition mirror map automorphism. In particular, we show that the
category of such mirror-twisted sectors for $V\otimes V$ is isomorphic to the
category of N=1 Ramond sectors for $V$.


title: Dynamic Equilibrium Limit Order Book Model and Optimal Execution Problem

abstract:
  In this paper we propose a dynamic model of Limit Order Book (LOB). The main
feature of our model is that the shape of the LOB is determined endogenously by
an expected utility function via a competitive equilibrium argument. Assuming
zero resilience, the resulting equilibrium density of the LOB is random,
nonlinear, and time inhomogeneous. Consequently, the liquidity cost can be
defined dynamically in a natural way.
  We next study an optimal execution problem in our model. We verify that the
value function satisfies the Dynamic Programming Principle, and is a viscosity
solution to the corresponding Hamilton-Jacobi-Bellman equation which is in the
form of an integro-partial-differential quasi-variational inequality. We also
prove the existence and analyze the structure of the optimal strategy via a
verification theorem argument, assuming that the PDE has a classical solution.


title:
The Broadband XMM-Newton and NuSTAR X-ray Spectra of Two Ultraluminous
  X-ray Sources in the Galaxy IC 342

abstract:
  We present results for two Ultraluminous X-ray Sources (ULXs), IC 342 X-1 and
IC 342 X-2, using two epochs of XMM-Newton and NuSTAR observations separated by
$\sim$7 days. We observe little spectral or flux variability above 1 keV
between epochs, with unabsorbed 0.3--30 keV luminosities being
$1.04^{+0.08}_{-0.06} \times 10^{40}$ erg s$^{-1}$ for IC 342 X-1 and
$7.40\pm0.20 \times 10^{39}$ erg s$^{-1}$ for IC 342 X-2, so that both were
observed in a similar, luminous state. Both sources have a high absorbing
column in excess of the Galactic value. Neither source has a spectrum
consistent with a black hole binary in low/hard state, and both ULXs exhibit
strong curvature in their broadband X-ray spectra. This curvature rules out
models that invoke a simple reflection-dominated spectrum with a broadened iron
line and no cutoff in the illuminating power-law continuum. X-ray spectrum of
IC 342 X-1 can be characterized by a soft disk-like black body component at low
energies and a cool, optically thick Comptonization continuum at high energies,
but unique physical interpretation of the spectral components remains
challenging. The broadband spectrum of IC 342 X-2 can be fit by either a hot
(3.8 keV) accretion disk, or a Comptonized continuum with no indication of a
seed photon population. Although the seed photon component may be masked by
soft excess emission unlikely to be associated with the binary system, combined
with the high absorption column, it is more plausible that the broadband X-ray
emission arises from a simple thin blackbody disk component. Secure
identification of the origin of the spectral components in these sources will
likely require broadband spectral variability studies.


title: Real solutions of a problem in enumerative geometry

abstract:
  We study a 2-parameter family of enumerative problems over the reals. Over
the complex field, these problems can be solved by Schubert calculus. In the
real case the number of solutions can be different on the distinct connected
components of the configuration space, resulting in a solution function. The
cohomology calculation in the real case only gives the signed sum of the
solutions, therefore in general it only gives a lower bound on the range of the
solution function. We calculate the solution function for the 2-parameter
family and we show that in the even cases the solution function is constant
modulo 4. We show how to determine the sign of a solution and describe the
connected components of the configuration space. We translate the problem to
the language of quivers and also give a geometric interpretation of the sign.
Finally, we discuss what aspects might be considered when solving other real
enumerative problems.


title: Globally Hyperbolic Moment System by Generalized Hermite Expansion

abstract:
  In a recent paper [Z.-N. Cai, Y.-W. Fan, and R. Li. Tech Report, Institude of
Math, Peking Univeristy(2013)], it was revealed that a modified 13-moment
system taking intrinsic heat fluxes as variables, instead of the heat fluxes
along the coordinate vectors which is adopted in the classical Grad 13-moment
system, attains some additional advantages than the classical Grad 13-moment
system, particularly including that the equilibrium is turned to be the
interior point of its hyperbolicity region. The modified 13-moment system was
actually derived from the generalized Hermite expansion of the distribution
function, where the anisotropy of Hermite expansion is specified by the full
temperature tensor. We extend the method therein in this paper to high order of
generalized Hermite expansion to derive arbitrary order moment systems, and
proposed a globally hyperbolic regularization to achieve locally well-posedness
similar to the method in [Z. Cai, Y. Fan, and R. Li, Comm. Pure Appl.
Math.(online)(2013)]. Furthermore, the structure of the eigen-system of the
coefficient matrix and all characteristic waves are fully clarified. The
obtained systems provide a systematic class of hydrodynamic models as the
refined version of Euler equations, which is gradually approaching the
Boltzmann equation with increasing order of the expansion.


title: Testing the Bardeen metric with the black hole candidate in Cygnus X-1

abstract:
  In general, it is very difficult to test the Kerr-nature of an astrophysical
black hole candidate, because it is not possible to have independent
measurements of both the spin parameter $a_*$ and possible deviations from the
Kerr solution. Non-Kerr objects may indeed look like Kerr black holes with
different spin. However, it is much more difficult to mimic an extremal Kerr
black hole. The black hole candidate in Cygnus X-1 has the features of a near
extremal Kerr black hole, and it is therefore a good object to test the Kerr
black hole paradigm. The 3$\sigma$-bounds $a_* > 0.95$ and $a_* > 0.983$
reported in the literature and valid in the Kerr spacetime become,
respectively, $a_* > 0.78$ and $|g/M| < 0.41$, and $a_* > 0.89$ and $|g/M| <
0.28$ in the Bardeen metric, where $g$ is the Bardeen charge of the black hole.


title:
The Morphological Transformation of Red-Sequence Galaxies in the Distant
  Cluster XMMU J1229+0151

abstract:
  We present the results of a detailed analysis of galaxy properties along the
red sequence in XMMU J1229+0151, an X-ray selected cluster at $z=0.98$ drawn
from the HAWK-I Cluster Survey (HCS). Taking advantage of the broad photometric
coverage and the availability of 77 spectra in the cluster field, we fit
synthetic spectral energy distributions, and estimate stellar masses and
photometric redshifts, which we use to determine the cluster membership. We
investigate morphological and structural properties of red sequence galaxies
and find that elliptical galaxies populate the bright end, while S0 galaxies
represent the predominant population at intermediate luminosities, with their
fraction decreasing at fainter magnitudes. A comparison with the low-redshift
sample of the WINGS cluster survey reveals that at $z\sim1$ the bright end of
the red sequence of XMMU J1229+0151 is richer in S0 galaxies. The faint end of
the red sequence in XMMUJ1229+0151 appears rich in disc-dominated galaxies,
which are rarer in the low redshift comparison sample at the same luminosities.
Despite these differences between the morphological composition of the red
sequence in XMMUJ1229+0151 and in low redshift samples, we find that to within
the uncertainties, no such difference exists in the ratio of luminous to faint
galaxies along the red sequence.


title: On the Capacity of Memoryless Adversary

abstract:
  In this paper, we study a model of communication under adversarial noise. In
this model, the adversary makes online decisions on whether to corrupt a
transmitted bit based on only the value of that bit. Like the usual binary
symmetric channel of information theory or the fully adversarial channel of
combinatorial coding theory, the adversary can, with high probability,
introduce at most a given fraction of error.
  It is shown that, the capacity (maximum rate of reliable information
transfer) of such memoryless adversary is strictly below that of the binary
symmetric channel. We give new upper bound on the capacity of such channel --
the tightness of this upper bound remains an open question. The main component
of our proof is the careful examination of error-correcting properties of a
code with skewed distance distribution.


title: On Two Ways to Look for Mutually Unbiased Bases

abstract:
  Two equivalent ways of looking for mutually unbiased bases are discussed in
this note. The passage from the search for d+1 mutually unbiased bases in C(d)
to the search for d(d+1) vectors in C(d*d) satisfying constraint relations is
clarified. Symmetric informationally complete positive-operator-valued measures
are briefly discussed in a similar vein.


title:
Time series modeling and large scale global solar radiation forecasting
  from geostationary satellites data

abstract:
  When a territory is poorly instrumented, geostationary satellites data can be
useful to predict global solar radiation. In this paper, we use geostationary
satellites data to generate 2-D time series of solar radiation for the next
hour. The results presented in this paper relate to a particular territory, the
Corsica Island, but as data used are available for the entire surface of the
globe, our method can be easily exploited to another place. Indeed 2-D hourly
time series are extracted from the HelioClim-3 surface solar irradiation
database treated by the Heliosat-2 model. Each point of the map have been used
as training data and inputs of artificial neural networks (ANN) and as inputs
for two persistence models (scaled or not). Comparisons between these models
and clear sky estimations were proceeded to evaluate the performances. We found
a normalized root mean square error (nRMSE) close to 16.5% for the two best
predictors (scaled persistence and ANN) equivalent to 35-45% related to ground
measurements. Finally in order to validate our 2-D predictions maps, we
introduce a new error metric called the gamma index which is a criterion for
comparing data from two matrixes in medical physics. As first results, we found
that in winter and spring, scaled persistence gives the best results (gamma
index test passing rate is respectively 67.7% and 86%), in autumn simple
persistence is the best predictor (95.3%) and ANN is the best in summer
(99.8%).


title:
Hunting A Wandering Supermassive Black Hole in M31 Halo -- Hermitage of
  Black Hole

abstract:
  In the hierarchical structure formation scenario, galaxies enlarge through
multiple merging events with less massive galaxies. In addition, the Magorrian
relation indicates that almost all galaxies are occupied by a central
supermassive black hole (SMBH) of mass $10^{-3}$ of its spheroidal component.
Consequently, SMBHs are expected to wander in the halos of their host galaxies
following a galaxy collision, although evidence of this activity is currently
lacking. We investigate a current plausible location of an SMBH wandering in
the halo of the Andromeda galaxy (M31). According to theoretical studies of
$N$-body simulations, some of the many substructures in the M31 halo are
remnants of a minor merger occurring about 1 Gyr ago. First, to evaluate the
possible parameter space of the infalling orbit of the progenitor, we perform
numerous parameter studies using a Graphics Processing Unit (GPU) cluster. To
reduce uncertainties in the predicted position of the expected SMBH, we then
calculate the time evolution of the SMBH in the progenitor dwarf galaxy from
$N$-body simulations using the plausible parameter sets. Our results show that
the SMBH lies within the halo ($\sim$20--50 kpc from the M31 center), closer to
the Milky Way than the M31 disk. Furthermore, the predicted current positions
of the SMBH were restricted to an observational field of $0\degr.6 \times
0\degr.7$ in the northeast region of the M31 halo. We also discuss the origin
of the infalling orbit of the satellite galaxy and its relationships with the
recently discovered vast thin disk plane of satellite galaxies around M31.


title: An adaptive observer for wave equation's source estimation

abstract:
  Observers are well known in control theory. Originally designed to estimate
the hidden states of dynamical systems given some measurements, the observers
scope has been recently extended to the estimation of some unknowns, for
systems governed by partial differential equations. In this paper, observers
are used to solve inverse source problem for a one-dimensional wave equation.
An adaptive observer is designed to estimate the state and source components
for a fully discretized system. The effectiveness of the method is emphasized
in noise-free and noisy cases and an insight on the impact of measurements'
size and location is provided.


title:
Auxiliary field Monte-Carlo simulation of strong coupling lattice QCD
  for QCD phase diagram

abstract:
  We study the QCD phase diagram in the strong coupling limit with fluctuation
effects by using the auxiliary field Monte-Carlo method. We apply the chiral
angle fixing technique in order to obtain finite chiral condensate in the
chiral limit in finite volume. The behavior of order parameters suggests that
chiral phase transition is the second order or crossover at low chemical
potential and the first order at high chemical potential. Compared with the
mean field results, the hadronic phase is suppressed at low chemical potential,
and is extended at high chemical potential as already suggested in the
monomer-dimer-polymer simulations. We find that the sign problem originating
from the bosonization procedure is weakened by the phase cancellation
mechanism; a complex phase from one site tends to be canceled by the nearest
neighbor site phase as long as low momentum auxiliary field contributions
dominate.


title: Visual Tracking using Particle Swarm Optimization

abstract:
  The problem of robust extraction of visual odometry from a sequence of images
obtained by an eye in hand camera configuration is addressed. A novel approach
toward solving planar template based tracking is proposed which performs a
non-linear image alignment for successful retrieval of camera transformations.
In order to obtain global optimum a bio-metaheuristic is used for optimization
of similarity among the planar regions. The proposed method is validated on
image sequences with real as well as synthetic transformations and found to be
resilient to intensity variations. A comparative analysis of the various
similarity measures as well as various state-of-art methods reveal that the
algorithm succeeds in tracking the planar regions robustly and has good
potential to be used in real applications.


title: On reaping number having countable cofinality

abstract:
  We prove that if the bounding number (d) is bigger than the reaping number
(r), then the latter has uncountable cofinality.


title: A Gray Code for cross-bifix-free sets

abstract:
  A cross-bifix-free set of words is a set in which no prefix of any length of
any word is the suffix of any other word in the set. A construction of
cross-bifix-free sets has recently been proposed by Chee {\it et al.} in 2013
within a constant factor of optimality. We propose a \emph{trace partitioned}
Gray code for these cross-bifix-free sets and a CAT algorithm generating it.


title:
Inhomogeneous condensates in dilute nuclear matter and BCS-BEC
  crossovers

abstract:
  We report on recent progress in understanding pairing phenomena in
low-density nuclear matter at small and moderate isospin asymmetry. A rich
phase diagram has been found comprising various superfluid phases that include
a homogeneous and phase-separated BEC phase of deuterons at low density and a
homogeneous BCS phase, an inhomogeneous LOFF phase, and a phase-separated BCS
phase at higher densities. The transition from the BEC phases to the BCS phases
is characterized in terms of the evolution, from strong to weak coupling, of
the condensate wavefunction and the second moment of its density distribution
in $r$-space. We briefly discuss approaches to higher-order clustering in
low-density nuclear matter.


title:
Self-organization in the Earth climate system versus Milankovitch-Berger
  astronomical cycles

abstract:
  The Late Pleistocene Antarctic temperature variation curve is decomposed into
two parts: cyclic and stochastic. These two parts represent different but
tightly interconnected processes and also represent two different types of
self-organization of the Earth climate system. The self-organization in the
cyclic component is the non-linear auto-oscillation reaction of the Earth
climate system, as a whole, to the input of solar radiation. The
self-organization in the stochastic component is a nonlinear critical process,
taking energy from, and fluctuating around the cyclic component of the
temperature variations. The system of ODEs is written to model the cyclic part
of the temperature variation, and the multifractal spectrum of the stochastic
part of the temperature variation is calculated. The Earth climate can be
characterized as an open, complex, self-organized dynamical system with
nonlinear reaction to the input of solar radiation.


title:
On the beam spin asymmetries of electroproduction of charged hadrons off
  the nucleon targets

abstract:
  We study the beam single-spin asymmetries $A_{LU}^{\sin\phi_h}$ for charged
hadrons produced in semi-inclusive deep inelastic scattering process, by
considering the $e H_1^\perp$ term and the $g^\perp D_1$ term simultaneously.
Besides the asymmetries for charged pions, for the first time we present the
analysis on the asymmetries in the production of charged kaons, protons and
antiprotons by longitudinally polarized leptons scattered off unpolarized
proton and deuteron targets. In our calculation we use two sets of transverse
momentum dependent distributions $g^\perp(x,\bm k_T^2)$ and $e(x,\bm k_T^2)$
calculated from two different spectator models, and compare the numerical
results with the preliminary data recently obtained by the HERMES
Collaboration. We also predict the beam spin asymmetries for $\pi^\pm$,
$K^\pm$, $p/\bar{p}$ electroproduction in semi-inclusive deep-inelastic
scattering of 12 GeV polarized electrons from unpolarized proton and deuteron
targets.


title: Tropical schemes, tropical cycles, and valuated matroids

abstract:
  We show that the weights on a tropical variety can be recovered from the
tropical scheme structure proposed by the Giansiracusas in arXiv:1308.0042, so
there is a well-defined Hilbert-Chow morphism from a tropical scheme to the
underlying tropical cycle. For a subscheme of projective space given by a
homogeneous ideal I we show that this tropical scheme structure contains the
same information as the set of valuated matroids of the vector spaces I_d for d
\geq 0. We also give a combinatorial criterion to determine whether a given
relation is in the congruence defining the tropical scheme structure.


title:
The Energy/Frequency Convexity Rule: Modeling and Experimental
  Validation on Mobile Devices

abstract:
  This paper provides both theoretical and experimental evidence for the
existence of an Energy/Frequency Convexity Rule, which relates energy
consumption and CPU frequency on mobile devices. We monitored a typical
smartphone running a specific computing-intensive kernel of multiple nested
loops written in C using a high-resolution power gauge. Data gathered during a
week-long acquisition campaign suggest that energy consumed per input element
is strongly correlated with CPU frequency, and, more interestingly, the curve
exhibits a clear minimum over a 0.2 GHz to 1.6 GHz window. We provide and
motivate an analytical model for this behavior, which fits well with the data.
Our work should be of clear interest to researchers focusing on energy usage
and minimization for mobile devices, and provide new insights for optimization
opportunities.


title: Extending structures for 3-Lie algebras

abstract:
  The cohomology and deformation theory of 3-Lie algebras are revisited. The
theory of extending structures and unified product for 3-Lie algebras are
developed.It is proved that the extending structures of 3-Lie algebras can be
classified by using some non-abelian cohomology and deformation map theory.


title: Power Control Factor Selection in Uplink OFDMA Cellular Networks

abstract:
  Uplink power control plays a key role on the performance of uplink cellular
network. In this work, the power control factor ($\in[0,1]$) is evaluated based
on three parameters namely: average transmit power, coverage probability and
average rate. In other words, we evaluate power control factor such that
average transmit power should be low, coverage probability of cell-edge users
should be high and also average rate over all the uplink users should be high.
We show through numerical studies that the power control factor should be close
to $0.5$ in order to achieve an acceptable trade-off between these three
parameters.


title: Computation Tree Logic Model Checking Based on Possibility Measures

abstract:
  In order to deal with the systematic verification with uncertain infromation
in possibility theory, Li and Li \cite{li12} introduced model checking of
linear-time properties in which the uncertainty is modeled by possibility
measures. Xue, Lei and Li \cite{Xue09} defined computation tree logic (CTL)
based on possibility measures, which is called possibilistic CTL (PoCTL). This
paper is a continuation of the above work. First, we study the expressiveness
of PoCTL. Unlike probabilistic CTL, it is shown that PoCTL (in particular,
qualitative PoCTL) is more powerful than CTL with respect to their
expressiveness. The equivalent expressions of basic CTL formulae using
qualitative PoCTL formulae are presented in detail. Some PoCTL formulae that
can not be expressed by any CTL formulae are presented. In particular, some
qualitative properties of repeated reachability and persistence are expressed
using PoCTL formulae. Next, adapting CTL model-checking algorithm, a method to
solve the PoCTL model-checking problem and its time complexity are discussed in
detail. Finally, an example is given to illustrate the PoCTL model-checking
method.


title:
Search of double shell closure in the superheavy nuclei using a simple
  effective interaction

abstract:
  This paper refers to an another attempt to search for spherical double shell
closure nu- clei beyond Z=82, N=126. All calculations and results are based on
a newly developed approach entitled as simple effective interaction. Our
results predict the combination of magic nucleus occurs at N=182
(Z=114,120,126). All possible evidences for the oc- currence of magic nuclei
are discussed systematically. And, the obtained results for all observables
compared with the relativistic mean field theory for NL3 parameter.


title:
On the Resilience of an Ant-based System in Fuzzy Environments. An
  Empirical Study

abstract:
  The current work describes an empirical study conducted in order to
investigate the behavior of an optimization method in a fuzzy environment.
MAX-MIN Ant System, an efficient implementation of a heuristic method is used
for solving an optimization problem derived from the Traveling Salesman Problem
(TSP). Several publicly-available symmetric TSP instances and their fuzzy
variants are tested in order to extract some general features. The entry data
was adapted by introducing a two-dimensional systematic degree of fuzziness,
proportional with the number of nodes, the dimension of the instance and also
with the distances between nodes, the scale of the instance. The results show
that our proposed method can handle the data uncertainty, showing good
resilience and adaptability.


title:
Significance level and positivity bias as causes for high rate of
  non-reproducible scientific results?

abstract:
  The high fraction of published results that turn out to be incorrect is a
major concern of today's science. This paper contributes to the understanding
of this problem in two independent directions. First, Johnson's recent claim
that hypothesis testing with a significance level of 0.05 can alone lead to an
unacceptably large proportion of false positives among all results is shown to
be unfounded. Second, a way to quantify the effect of "positivity bias" (the
tendency to consider only positive results as worthwhile) is introduced. We
estimate the proportion of false positives among positive results in terms of
the significance level used and the positivity ratio. The latter quantity is
the fraction of positive results over all results, be they positive or not,
published or not. In particular, if one uses a significance level of 0.05, and
produces 4 (possibly unpublished) negative results for every positive result,
then the proportion of false positives among positive results can climb to a
high 21%.


title:
Optimal Thresholds for Coverage and Rate in FFR Schemes for Planned
  Cellular Networks

abstract:
  Fractional frequency reuse (FFR) is an inter-cell interference coordination
scheme that is being actively researched for emerging wireless cellular
networks. In this work, we consider hexagonal tessellation based planned FFR
deployments, and derive expressions for the coverage probability and normalized
average rate for the downlink. In particular, given reuse $\frac{1}{3}$ (FR$3$
) and reuse $1$ (FR$1$) regions, and a Signal-to-Interference-plus-noise-Ratio
(SINR) threshold $S_{th}$ which decides the user assignment to either the FR$1$
or FR$3$ regions, we theoretically show that: $(i)$ The optimal choice of
$S_{th}$ which maximizes the coverage probability is $S_{th} = T$, where $T$ is
the required target SINR (for ensuring coverage), and $(ii)$ The optimal choice
of $S_{th}$ which maximizes the normalized average rate is given by the
expression $S_{th}=\max(T, T')$, where $T'$ is a function of the path loss
exponent and the fade parameters. For the optimal choice of $S_{th}$, we show
that FFR gives a higher rate than FR$1$ and a better coverage probability than
FR$3$. The impact of frequency correlation over the sub-bands allocated to the
FR$1$ and FR$3$ regions is analysed, and it is shown that correlation decreases
the average rate of the FFR network. Numerical results are provided, and these
match with the analytical results.


title:
Impact of Correlation between Nakagami-m Interferers on Coverage
  Probability and Rate in Cellular Systems

abstract:
  Coverage probability and rate expressions are theoretically compared for the
following cases: $(i).$ Both the user channel and the $N$ interferers are
independent and non identical Nakagami-m distributed random variables (RVs).
$(ii).$ The $N$ interferers are correlated Nakagami-m RVs. It is analytically
shown that the coverage probability in the presence of correlated interferers
is greater than or equal to the coverage probability in the presence of
non-identical independent interferers when the shape parameter of the channel
between the user and its base station is not greater than one. It is further
analytically shown that the average rate in the presence of correlated
interferers is greater than or equal to the average rate in the presence of
non-identical independent interferers. Simulation results are provided and
these match with the obtained theoretical results. The utility of our results
are also discussed.


title: Mathematical Foundations for the Economy of Giving

abstract:
  This paper shows how we can build a model for transactions when goods are
given away in the expectation of a later settlement. In settings where people
keep track of their social accounts we are able to redefine concepts like
account balance, yield curve and the law of diminishing returns. The model
provides us with a result that expresses how people have a structural
preference for one recipient over the other regardless the actual account
balance. Hence a building block in the social fabric of a community. Finally, a
fundamental theorem is presented to show how suppliers and recipients use their
account balance in order to reach an equilibrium in the exchange of goods much
like the traditional balance between supply and demand.


title:
Formation of gapless triplets in the bond-doped spin-gap antiferromagnet
  (C$_4$H$_{12}$N$_2$)(Cu$_2$Cl$_6$)

abstract:
  We report results of an electron spin resonance (ESR) study of a spin-gap
antiferromagnet (C$_4$H$_{12}$N$_2$)(Cu$_2$Cl$_6$) (nicknamed PHCC) with
chlorine ions partially substituted by bromine. We found that up to 10% of
nominal doping the contribution of the random defects to the absorption spectra
remains at about 0.1% per copper ion, almost the same as in the pure system.
Instead, a particular kind of ESR absorption corresponding to gapless S=1
triplets is observed at low temperatures in samples with high nominal bromine
content x>5%. Increase of bromine concentration also leads to the systematic
broadening of ESR absorption line indicating reduction of the quasi-particles
lifetime.


title: Parallel Telescoping and Parameterized Picard--Vessiot Theory

abstract:
  Parallel telescoping is a natural generalization of differential
creative-telescoping for single integrals to line integrals. It computes a
linear ordinary differential operator $L$, called a parallel telescoper, for
several multivariate functions, such that the applications of $L$ to the
functions yield antiderivatives of a single function. We present a necessary
and sufficient condition guaranteeing the existence of parallel telescopers for
differentially finite functions, and develop an algorithm to compute minimal
ones for compatible hyperexponential functions. Besides computing annihilators
of parametric line integrals, we use the parallel telescoping for determining
Galois groups of parameterized partial differential systems of first order.


title: $\Lambda$CDM-type cosmological model and observational constraints

abstract:
  In the present work, we have searched the existence of $\Lambda$CDM-type
cosmological model in anisotropic Heckmann-Schucking space-time. The matter
source that is responsible for the present acceleration of the universe consist
of cosmic fluid with $p = \omega\rho$, where $\omega$ is the equation of state
parameter. The Einstein's field equations have been solved explicitly under
some specific choice of parameters that isotropizes the model under
consideration. It has been found that the derived model is in good agreement
with recent SN Ia observations. Some physical aspects of the model has been
discussed in detail.


title:
Mean-Field Analysis of Orientation Selectivity in Inhibition-Dominated
  Networks of Spiking Neurons

abstract:
  Mechanisms underlying the emergence of orientation selectivity in the primary
visual cortex are highly debated. Here we study the contribution of
inhibition-dominated random recurrent networks to orientation selectivity, and
more generally to sensory processing. By simulating and analyzing large-scale
networks of spiking neurons, we investigate tuning amplification and contrast
invariance of orientation selectivity in these networks. In particular, we show
how selective attenuation of the common mode and amplification of the
modulation component take place in these networks. Selective attenuation of the
baseline, which is governed by the exceptional eigenvalue of the connectivity
matrix, removes the unspecific, redundant signal component and ensures the
invariance of selectivity across different contrasts. Selective amplification
of modulation, which is governed by the operating regime of the network and
depends on the strength of coupling, amplifies the informative signal component
and thus increases the signal-to-noise ratio. Here, we perform a mean-field
analysis which accounts for this process.


title:
Single Photoelectron Detection after Selective Excitation of
  Electron-Heavy Hole and Electron-Light Hole Pairs in Double Quantum Dots

abstract:
  We demonstrate the real-time detection of single photogenerated electrons in
two different lateral double quantum dots made in AlGaAs/GaAs/AlGaAs quantum
wells having a thin or a thick AlGaAs barrier layer. The observed incident
laser power and photon energy dependences of the photoelectron detection
efficiency both indicate that the trapped photoelectrons are, for the thin
barrier sample, predominantly photogenerated in the buffer layer followed by
tunneling into one of the two dots, whereas for the thick barrier sample they
are directly photogenerated in the well. For the latter, single photoelectron
detection after selective excitation of the heavy and light hole state in the
dot is well resolved. This ensures the applicability of our quantum well-based
quantum dot systems for the coherent transfer from single photon polarization
to single electron spin states.