title: Reductive groups, the loop Grassmannian, and the Springer resolution

abstract:
  In this paper we prove equivalences of categories relating the derived
category of a block of the category of representations of a connected reductive
algebraic group over an algebraically closed field of characteristic $p$ bigger
than the Coxeter number and a derived category of equivariant coherent sheaves
on the Springer resolution (or a parabolic counterpart). In the case of the
principal block, combined with previous results, this provides a modular
version of celebrated constructions due to Arkhipov-Bezrukavnikov-Ginzburg for
Lusztig's quantum groups at a root of unity. As an application, we prove a
"graded version" of a conjecture of Finkelberg-Mirkovi\'c describing the
principal block in terms of mixed perverse sheaves on the dual affine
Grassmannian.


title: Bias-modulated dynamics of a strongly driven two-level system

abstract:
  We investigate the bias-modulated dynamics of a strongly driven two-level
system using the counter-rotating-hybridized rotating-wave (CHRW) method. This
CHRW method treats the driving field and the bias on equal footing by a unitary
transformation with two parameters $\xi$ and $\zeta$, and is nonperturbative in
driving strength, tunneling amplitude or bias. In addition, this CHRW method is
beyond the traditional rotating-wave approximation (Rabi-RWA) and yet by
properly choosing the two parameters $\xi$ and $\zeta$, the transformed
Hamiltonian takes the RWA form with a renormalized energy splitting and a
renormalized driving strength. The reformulated CHRW method possesses the same
mathematical simplicity as the Rabi-RWA approach and thus allows us to
calculate analytically the dynamics and explore explicitly the effect of the
bias. We show that the CHRW method gives the accurate driven dynamics for a
wide range of parameters as compared to the numerically exact results. When
energy scales of the driving are comparable to the intrinsic energy scale of
the two-level systems, the counter-rotating interactions and static bias
profoundly influence the generalized Rabi frequency. In this regime, where
ordinary perturbation approaches fail, the CHRW works very well and
efficiently. We also demonstrate the dynamics of the system in the
strong-driving and off-resonance cases for which the Rabi-RWA method breaks
down but the CHRW method remains valid. We obtain analytical expressions for
the generalized Rabi frequency and bias-modulated Bloch-Siegert shift as
functions of the bias, tunneling and driving field parameters. The CHRW
approach is a mathematically simple and physically clear method. It can be
applied to treat some complicated problems for which a numerical study is
difficult to perform.


title: Temperature-aware Dynamic Optimization of Embedded Systems

abstract:
  Due to embedded systems` stringent design constraints, much prior work
focused on optimizing energy consumption and/or performance. Since embedded
systems typically have fewer cooling options, rising temperature, and thus
temperature optimization, is an emergent concern. Most embedded systems only
dissipate heat by passive convection, due to the absence of dedicated thermal
management hardware mechanisms. The embedded system`s temperature not only
affects the system`s reliability, but could also affect the performance, power,
and cost. Thus, embedded systems require efficient thermal management
techniques. However, thermal management can conflict with other optimization
objectives, such as execution time and energy consumption. In this paper, we
focus on managing the temperature using a synergy of cache optimization and
dynamic frequency scaling, while also optimizing the execution time and energy
consumption. This paper provides new insights on the impact of cache parameters
on efficient temperature-aware cache tuning heuristics. In addition, we present
temperature-aware phase-based tuning, TaPT, which determines Pareto optimal
clock frequency and cache configurations for fine-grained execution time,
energy, and temperature tradeoffs. TaPT enables autonomous system optimization
and also allows designers to specify temperature constraints and optimization
priorities. Experiments show that TaPT can effectively reduce execution time,
energy, and temperature, while imposing minimal hardware overhead.


title:
Phase distance mapping: a phase-based cache tuning methodology for
  embedded systems

abstract:
  Networked embedded systems typically leverage a collection of low-power
embedded systems (nodes) to collaboratively execute applications spanning
diverse application domains (e.g., video, image processing, communication,
etc.) with diverse application requirements. The individual networked nodes
must operate under stringent constraints (e.g., energy, memory, etc.) and
should be specialized to meet varying application requirements in order to
adhere to these constraints. Phase-based tuning specializes system tunable
parameters to the varying runtime requirements of different execution phases to
meet optimization goals. Since the design space for tunable systems can be very
large, one of the major challenges in phase-based tuning is determining the
best configuration for each phase without incurring significant tuning overhead
(e.g., energy and/or performance) during design space exploration. In this
paper, we propose phase distance mapping, which directly determines the best
configuration for a phase, thereby eliminating design space exploration. Phase
distance mapping applies the correlation between the characteristics and best
configuration of a known phase to determine the best configuration of a new
phase. Experimental results verify that our phase distance mapping approach,
when applied to cache tuning, determines cache configurations within 1 % of the
optimal configurations on average and yields an energy delay product savings of
27 % on average.


title:
Non-positive-partial-transpose quantum states of rank four are
  distillable

abstract:
  We show that any bipartite quantum state of rank four is distillable, when
the partial transpose of the state has at least one negative eigenvalue, i.e.,
the state is NPT. For this purpose we prove that if the partial transpose of a
two-qutrit NPT state has two non-positive eigenvalues, then the state is
distillable. We further construct a parametrized two-qutrit NPT entangled state
of rank five which is not 1-distillable, and show that it is not
$n$-distillable for any given $n$ when the parameter is sufficiently small.
This state has the smallest rank among all 1-undistillable NPT states. We
conjecture that the state is not distillable.


title: The scale function and lattices

abstract:
  It is shown that, given a lattice H in a totally disconnected, locally
compact group G, the contraction subgroups in G and the values of the scale
function on G are determined by their restrictions to H. Group theoretic
properties intrinsic to the lattice, such as being periodic or infinitely
divisible, are then seen to imply corresponding properties of G.


title:
Identifiability Assumptions and Algorithm for Directed Graphical Models
  with Feedback

abstract:
  Directed graphical models provide a useful framework for modeling causal or
directional relationships for multivariate data. Prior work has largely focused
on identifiability and search algorithms for directed acyclic graphical (DAG)
models. In many applications, feedback naturally arises and directed graphical
models that permit cycles occur. In this paper we address the issue of
identifiability for general directed cyclic graphical (DCG) models satisfying
the Markov assumption. In particular, in addition to the faithfulness
assumption which has already been introduced for cyclic models, we introduce
two new identifiability assumptions, one based on selecting the model with the
fewest edges and the other based on selecting the DCG model that entails the
maximum number of d-separation rules. We provide theoretical results comparing
these assumptions which show that: (1) selecting models with the largest number
of d-separation rules is strictly weaker than the faithfulness assumption; (2)
unlike for DAG models, selecting models with the fewest edges does not
necessarily result in a milder assumption than the faithfulness assumption. We
also provide connections between our two new principles and minimality
assumptions. We use our identifiability assumptions to develop search
algorithms for small-scale DCG models. Our simulation study supports our
theoretical results, showing that the algorithms based on our two new
principles generally out-perform algorithms based on the faithfulness
assumption in terms of selecting the true skeleton for DCG models.


title:
Minimizing Message Size in Stochastic Communication Patterns: Fast
  Self-Stabilizing Protocols with 3 bits

abstract:
  This paper considers the basic $\mathcal{PULL}$ model of communication, in
which in each round, each agent extracts information from few randomly chosen
agents. We seek to identify the smallest amount of information revealed in each
interaction (message size) that nevertheless allows for efficient and robust
computations of fundamental information dissemination tasks. We focus on the
Majority Bit Dissemination problem that considers a population of $n$ agents,
with a designated subset of source agents. Each source agent holds an input bit
and each agent holds an output bit. The goal is to let all agents converge
their output bits on the most frequent input bit of the sources (the majority
bit). Note that the particular case of a single source agent corresponds to the
classical problem of Broadcast. We concentrate on the severe fault-tolerant
context of self-stabilization, in which a correct configuration must be reached
eventually, despite all agents starting the execution with arbitrary initial
states.
  We first design a general compiler which can essentially transform any
self-stabilizing algorithm with a certain property that uses $\ell$-bits
messages to one that uses only $\log \ell$-bits messages, while paying only a
small penalty in the running time. By applying this compiler recursively we
then obtain a self-stabilizing Clock Synchronization protocol, in which agents
synchronize their clocks modulo some given integer $T$, within $\tilde O(\log
n\log T)$ rounds w.h.p., and using messages that contain $3$ bits only.
  We then employ the new Clock Synchronization tool to obtain a
self-stabilizing Majority Bit Dissemination protocol which converges in $\tilde
O(\log n)$ time, w.h.p., on every initial configuration, provided that the
ratio of sources supporting the minority opinion is bounded away from half.
Moreover, this protocol also uses only 3 bits per interaction.


title:
A Comparison of Policies on the Participation of Storage in U.S.
  Frequency Regulation Markets

abstract:
  Because energy storage systems have better ramping characteristics than
traditional generators, their participation in frequency regulation should
facilitate the balancing of load and generation. However, they cannot sustain
their output indefinitely. System operators have therefore implemented new
frequency regulation policies to take advantage of the fast ramps that energy
storage systems can deliver while alleviating the problems associated with
their limited energy capacity. This paper contrasts several U.S. policies that
directly affect the participation of energy storage systems in frequency
regulation and compares the revenues that the owners of such systems might
achieve under each policy.


title: Randomized approximate nearest neighbor search with limited adaptivity

abstract:
  We study the fundamental problem of approximate nearest neighbor search in
$d$-dimensional Hamming space $\{0,1\}^d$. We study the complexity of the
problem in the famous cell-probe model, a classic model for data structures. We
consider algorithms in the cell-probe model with limited adaptivity, where the
algorithm makes $k$ rounds of parallel accesses to the data structure for a
given $k$. For any $k\ge 1$, we give a simple randomized algorithm solving the
approximate nearest neighbor search using $k$ rounds of parallel memory
accesses, with $O(k(\log d)^{1/k})$ accesses in total. We also give a more
sophisticated randomized algorithm using $O(k+(\frac{1}{k}\log d)^{O(1/k)})$
memory accesses in $k$ rounds for large enough $k$. Both algorithms use data
structures of size polynomial in $n$, the number of points in the database.
  For the lower bound, we prove an $\Omega(\frac{1}{k}(\log d)^{1/k})$ lower
bound for the total number of memory accesses required by any randomized
algorithm solving the approximate nearest neighbor search within
$k\le\frac{\log\log d}{2\log\log\log d}$ rounds of parallel memory accesses on
any data structures of polynomial size. This lower bound shows that our first
algorithm is asymptotically optimal for any constant round $k$. And our second
algorithm approaches the asymptotically optimal tradeoff between rounds and
memory accesses, in a sense that the lower bound of memory accesses for any
$k_1$ rounds can be matched by the algorithm within $k_2=O(k_1)$ rounds. In the
extreme, for some large enough $k=\Theta\left(\frac{\log\log d}{\log\log\log
d}\right)$, our second algorithm matches the $\Theta\left(\frac{\log\log
d}{\log\log\log d}\right)$ tight bound for fully adaptive algorithms for
approximate nearest neighbor search due to Chakrabarti and Regev.


title:
Hi Detector, What's Wrong with that Object? Identifying Irregular Object
  From Images by Modelling the Detection Score Distribution

abstract:
  In this work, we study the challenging problem of identifying the irregular
status of objects from images in an "open world" setting, that is,
distinguishing the irregular status of an object category from its regular
status as well as objects from other categories in the absence of "irregular
object" training data. To address this problem, we propose a novel approach by
inspecting the distribution of the detection scores at multiple image regions
based on the detector trained from the "regular object" and "other objects".
The key observation motivating our approach is that for "regular object" images
as well as "other objects" images, the region-level scores follow their own
essential patterns in terms of both the score values and the spatial
distributions while the detection scores obtained from an "irregular object"
image tend to break these patterns. To model this distribution, we propose to
use Gaussian Processes (GP) to construct two separate generative models for the
case of the "regular object" and the "other objects". More specifically, we
design a new covariance function to simultaneously model the detection score at
a single region and the score dependencies at multiple regions. We finally
demonstrate the superior performance of our method on a large dataset newly
proposed in this paper.


title: Market Dynamics. On Supply and Demand Concepts

abstract:
  The disbalance of Supply and Demand is typically considered as the driving
force of the markets. However, the measurement or estimation of Supply and
Demand at price different from the execution price is not possible even after
the transaction. An approach in which Supply and Demand are always matched, but
the rate $I=dv/dt$ (number of units traded per unit time) of their matching
varies, is proposed. The state of the system is determined not by a price $p$,
but by a probability distribution defined as the square of a wavefunction
$\psi(p)$. The equilibrium state $\psi^{[H]}$ is postulated to be the one
giving maximal $I$ and obtained from maximizing the matching rate functional
$<I\psi^2(p)>/<\psi^2(p)>$, i.e. solving the dynamic equation of the form
"future price tend to the value maximizing the number of shares traded per unit
time". An application of the theory in a quasi--stationary case is
demonstrated. This transition from Supply and Demand concept to Liquidity
Deficit concept, described by the matching rate $I$, allows to operate only
with observable variables, and have a theory applicable to practical problems.


title: On the reflection of solitons of the nonlinear Schrodinger equation

abstract:
  In this paper we perform a numerical study on the interesting phenomenon of
soliton reflection of solid walls. We consider the 2D nonlinear Schrodinger
equation as the underlying mathematical model and we use an implicit-explicit
type Crank-Nicolson finite element scheme for its numerical solution. After
verifying the perfect reflection of the solitons on a vertical wall, we present
the imperfect reflection of a dark soliton on a diagonal wall.


title: Dynamical Localization of Coupled Relativistic Kicked Rotors

abstract:
  A periodically driven rotor is a prototypical model that exhibits a
transition to chaos in the classical regime and dynamical localization (related
to Anderson localization) in the quantum regime. In a recent work [Phys. Rev. B
94, 085120 (2016)], A. C. Keser et al. considered a many-body generalization of
coupled quantum kicked rotors, and showed that in the special integrable linear
case, dynamical localization survives interactions. By analogy with many-body
localization, the phenomenon was dubbed dynamical many-body localization. In
the present work, we study nonintegrable models of single and coupled quantum
relativistic kicked rotors (QRKRs) that bridge the gap between the conventional
quadratic rotors and the integrable linear models. For a single QRKR, we
supplement the recent analysis of the angular-momentum-space dynamics with a
study of the spin dynamics. Our analysis of two and three coupled QRKRs along
with the proved localization in the many-body linear model indicate that
dynamical localization exists in few-body systems. Moreover, the relation
between QRKR and linear rotor models implies that dynamical many-body
localization can exist in generic, nonintegrable many-body systems. And
localization can generally result from a complicated interplay between Anderson
mechanism and limiting integrability, since the many-body linear model is a
high-angular-momentum limit of many-body QRKRs. We also analyze the dynamics of
two coupled QRKRs in the highly unusual superballistic regime and find that the
resonance conditions are relaxed due to interactions. Finally, we propose
experimental realizations of the QRKR model in cold atoms in optical lattices.


title:
On the low-rank approach for semidefinite programs arising in
  synchronization and community detection

abstract:
  To address difficult optimization problems, convex relaxations based on
semidefinite programming are now common place in many fields. Although solvable
in polynomial time, large semidefinite programs tend to be computationally
challenging. Over a decade ago, exploiting the fact that in many applications
of interest the desired solutions are low rank, Burer and Monteiro proposed a
heuristic to solve such semidefinite programs by restricting the search space
to low-rank matrices. The accompanying theory does not explain the extent of
the empirical success. We focus on Synchronization and Community Detection
problems and provide theoretical guarantees shedding light on the remarkable
efficiency of this heuristic.


title:
Exploiting Lists of Names for Named Entity Identification of Financial
  Institutions from Unstructured Documents

abstract:
  There is a wealth of information about financial systems that is embedded in
document collections. In this paper, we focus on a specialized text extraction
task for this domain. The objective is to extract mentions of names of
financial institutions, or FI names, from financial prospectus documents, and
to identify the corresponding real world entities, e.g., by matching against a
corpus of such entities. The tasks are Named Entity Recognition (NER) and
Entity Resolution (ER); both are well studied in the literature. Our
contribution is to develop a rule-based approach that will exploit lists of FI
names for both tasks; our solution is labeled Dict-based NER and Rank-based ER.
Since the FI names are typically represented by a root, and a suffix that
modifies the root, we use these lists of FI names to create specialized root
and suffix dictionaries. To evaluate the effectiveness of our specialized
solution for extracting FI names, we compare Dict-based NER with a general
purpose rule-based NER solution, ORG NER. Our evaluation highlights the
benefits and limitations of specialized versus general purpose approaches, and
presents additional suggestions for tuning and customization for FI name
extraction. To our knowledge, our proposed solutions, Dict-based NER and
Rank-based ER, and the root and suffix dictionaries, are the first attempt to
exploit specialized knowledge, i.e., lists of FI names, for rule-based NER and
ER.


title:
Difficulty in Formation of Counter-orbiting Hot Jupiters from
  Near-coplanar Hierarchical Triple Systems: A Sub-stellar Perturber

abstract:
  Among a hundred transiting planets with a measured projected spin-orbit angle
{\lambda}, several systems are suggested to be counter-orbiting. While they may
be due to the projection effect, the mechanism to produce a counter-orbiting
planet is not established. A promising scenario for the counter-orbiting
planets is the extreme eccentricity evolution in near-coplanar hierarchical
triple systems with eccentric inner and outer or- bits. We examine this
scenario in detail by performing a series of systematic numerical simulations,
and consider the possibility of forming hot Jupiters, especially counter-
orbiting one under this mechanism with a distant sub-stellar perturber. We
incorporate quadrupole and octupole secular gravitational interaction between
the two orbits, and also short-range forces (correction for general relativity,
star and inner planetary tide and rotational distortion) simultaneously. We
find that most of systems are tidally disrupted and that a small fraction of
survived planets turns out to be prograde. The formation of counter-orbiting
hot Jupiters in this scenario is possible only in a very restricted parameter
region, and thus very unlikely in practice.


title: The least error method for sparse solution reconstruction

abstract:
  This work deals with a regularization method enforcing solution sparsity of
linear ill-posed problems by appropriate discretization in the image space.
Namely, we formulate the so called least error method in an $\ell^1$ setting
and perform the convergence analysis by choosing the discretization level
according to an a priori rule, as well as two a posteriori rules, via the
discrepancy principle and the monotone error rule, respectively. Depending on
the setting, linear or sublinear convergence rates in the $\ell^1$-norm are
obtained under a source condition yielding sparsity of the solution. A part of
the study is devoted to analyzing the structure of the approximate solutions
and of the involved source elements.


title: A transitioning universe with anisotropic dark energy

abstract:
  In this paper, we present a model of transitioning universe with minimal
interaction between perfect fluid and anisotropic dark energy in Bianchi I
space-time. The two sources are assumed to minimally interacted and therefore
their energy momentum tensors are conserved separately. The explicit expression
for average scale factor are considered in hybrid form that gives time varying
deceleration parameter which describes both the early and late time physical
features of universe. We also discuss the physical and geometrical properties
of the model derived in this paper. The solution is interesting physically as
it explain accelerating universe as well as singularity free universe.


title:
Distributed Query Processing Plans generation using Teacher Learner
  Based Optimization

abstract:
  With the growing popularity, the number of data sources and the amount of
data has been growing very fast in recent years. The distribution of
operational data on disperse data sources impose a challenge on processing user
queries. In such database systems, the database relations required by a query
to answer may be stored at multiple sites. This leads to an exponential
increase in the number of possible equivalent or alternatives of a user query.
Though it is not computationally reasonable to explore exhaustively all
possible query plans in a large search space, thus a strategy is requisite to
produce optimal query plans in distributed database systems. The query plan
with most cost-effective option for query processing is measured necessary and
must be generated for a given query. This paper attempts to generate such
optimal query plans using a parameter less optimization technique
Teaching-Learner Based Optimization(TLBO). The TLBO algorithm was experiential
to go one better than the other optimization algorithms for the multi objective
unconstrained and constrained benchmark problems. Experimental comparisons of
TLBO based optimal plan generation with the multiobjective genetic algorithm
based distributed query plan generation algorithm shows that for higher number
of relations, the TLBO based algorithm is able to generate comparatively better
quality Top K query plans.


title: Logic Blog 2015f

abstract:
  The 2015 Logic Blog contains a large variety of results connected to logic,
some of them unlikely to be submitted to a journal. For the first time there is
a group theory part. There are results in higher randomness, and in computable
ergodic theory.


title: Unsupervised Domain Adaptation with Residual Transfer Networks

abstract:
  The recent success of deep neural networks relies on massive amounts of
labeled data. For a target task where labeled data is unavailable, domain
adaptation can transfer a learner from a different source domain. In this
paper, we propose a new approach to domain adaptation in deep networks that can
jointly learn adaptive classifiers and transferable features from labeled data
in the source domain and unlabeled data in the target domain. We relax a
shared-classifier assumption made by previous methods and assume that the
source classifier and target classifier differ by a residual function. We
enable classifier adaptation by plugging several layers into deep network to
explicitly learn the residual function with reference to the target classifier.
We fuse features of multiple layers with tensor product and embed them into
reproducing kernel Hilbert spaces to match distributions for feature
adaptation. The adaptation can be achieved in most feed-forward models by
extending them with new residual layers and loss functions, which can be
trained efficiently via back-propagation. Empirical evidence shows that the new
approach outperforms state of the art methods on standard domain adaptation
benchmarks.


title: Frequency Analysis of Temporal Graph Signals

abstract:
  This letter extends the concept of graph-frequency to graph signals that
evolve with time. Our goal is to generalize and, in fact, unify the familiar
concepts from time- and graph-frequency analysis. To this end, we study a joint
temporal and graph Fourier transform (JFT) and demonstrate its attractive
properties. We build on our results to create filters which act on the joint
(temporal and graph) frequency domain, and show how these can be used to
perform interference cancellation. The proposed algorithms are distributed,
have linear complexity, and can approximate any desired joint filtering
objective.


title: Random Forest Based Approach for Concept Drift Handling

abstract:
  Concept drift has potential in smart grid analysis because the socio-economic
behaviour of consumers is not governed by the laws of physics. Likewise there
are also applications in wind power forecasting. In this paper we present
decision tree ensemble classification method based on the Random Forest
algorithm for concept drift. The weighted majority voting ensemble aggregation
rule is employed based on the ideas of Accuracy Weighted Ensemble (AWE) method.
Base learner weight in our case is computed for each sample evaluation using
base learners accuracy and intrinsic proximity measure of Random Forest. Our
algorithm exploits both temporal weighting of samples and ensemble pruning as a
forgetting strategy. We present results of empirical comparison of our method
with original random forest with incorporated "replace-the-looser" forgetting
andother state-of-the-art concept-drfit classifiers like AWE2.


title: Autoregressive Moving Average Graph Filtering

abstract:
  One of the cornerstones of the field of signal processing on graphs are graph
filters, direct analogues of classical filters, but intended for signals
defined on graphs. This work brings forth new insights on the distributed graph
filtering problem. We design a family of autoregressive moving average (ARMA)
recursions, which (i) are able to approximate any desired graph frequency
response, and (ii) give exact solutions for tasks such as graph signal
denoising and interpolation. The design philosophy, which allows us to design
the ARMA coefficients independently from the underlying graph, renders the ARMA
graph filters suitable in static and, particularly, time-varying settings. The
latter occur when the graph signal and/or graph are changing over time. We show
that in case of a time-varying graph signal our approach extends naturally to a
two-dimensional filter, operating concurrently in the graph and regular time
domains. We also derive sufficient conditions for filter stability when the
graph and signal are time-varying. The analytical and numerical results
presented in this paper illustrate that ARMA graph filters are practically
appealing for static and time-varying settings, as predicted by theoretical
derivations.


title: The nature of the late B-type stars HD 67044 and HD 42035

abstract:
  While monitoring a sample of apparently slowly rotating superficially normal
bright late B and early A stars in the northern hemisphere, we have discovered
that HD 67044 and HD 42035, hitherto classified as normal late B-type stars,
are actually respectively a new chemically peculiar star and a new
spectroscopic binary containing a very slow rotator HD 42035 S with ultra-sharp
lines (vsini = 3.7 km/s) and a fast rotator HD 42035 B with broad lines. The
lines of Ti, Cr, Mn, Sr, Y, Zr and Ba are conspicuous features in the high
resolution SOPHIE spectrum of HD 67044. The HgII line at 3983.93 A is also
present as a weak feature. The composite spectrum of HD 42035 is characterised
by very sharp lines formed in HD 42035 S superimposed onto the shallow and
broad lines of HD 42035 B. These very sharp lines are mostly due to light
elements from C to Ni, the only heavy species definitely present are Sr and Ba.
Selected lines of 21 chemical elements from He up to Hg have been synthesized
using model atmospheres computed with ATLAS9 and the spectrum synthesis code
SYNSPEC48 including hyperfine structure of various isotopes when relevant.
Abundances of these key elements have been derived HD 67044 and HD 42035 S. HD
67044 is found to have distinct enhancements of Ti, Cr, Mn, Sr, Y, Zr, Ba and
Hg and underabundances in He, C, O, Ca and Sc which shows that this star is not
a superficially normal late B-type star, but actually is a new CP star most
likely of the HgMn type. HD 42035 S has provisional underabundances of the
light elements from C to Ti and overabundances of heavier elements up to
barium. More accurate fundamental parameters and abundances for HD 42035 S and
HD 42035 B will be derived if we manage to disentangle their spectra. They will
help clarify the status of the two components in this interesting new
spectroscopic binary.


title:
Ultra-sensitive nanoscale magnetic field sensors based on resonant spin
  filtering

abstract:
  Solid state magnetic field sensors based on magneto-resistance modulation
find direct applications in communication devices, specifically in proximity
detection, rotational reference detection and current sensing. In this work, we
propose sensor structures based on the magneto-resistance physics of resonant
spin-filtering and present device designs catered toward exceptional magnetic
field sensing capabilities. Using the non-equilibrium Green's function spin
transport formalism self consistently coupled to the Poisson's equation, we
present highly-tunable pentalayer magnetic tunnel junction structures that are
capable of exhibiting an ultra-high peak tunnel magneto resistance $(\approx
2500 \%$). We show how this translates to device designs featuring an
ultra-high current sensitivity enhancement of over 300\% in comparison with
typical trilayer MTJ sensors, and a wider tunable range of field sensitivity.
We also demonstrate that a dynamic variation in sensor functionalities with the
structural landscape enables a superior design flexibility over typical
trilayer sensors. An optimal design exhibiting close to a 700\% sensitivity
increase as a result of angle dependent spin filtering is then presented.This
work sets a stage to engineer spintronic building blocks via the design of
functional structures tailored to exhibit ultra-sensitive spin filtering.


title: Residual-Bridge Constructs for Conditioned Diffusions

abstract:
  We introduce a new residual-bridge proposal for approximately simulating
conditioned diffusions. This proposal is formed by applying the modified
diffusion bridge approximation of Durham and Gallant (2002) to the difference
between the true diffusion and a second, approximate diffusion driven by the
same Brownian motion, and can be viewed as a natural extension to recent work
on residual-bridge constructs (Whitaker et al., 2016). This new proposal
attempts to account for volatilities which are not constant and can therefore
lead to gains in efficiency over the recently proposed residual-bridge
constructs in situations where the volatility varies considerably, as is often
the case for larger inter-observation times and for time-inhomogeneous
volatilities. These potential gains in efficiencies are illustrated via a
simulation study.


title:
A new scheme for maximizing the lifetime of heterogeneous wireless
  sensor networks

abstract:
  Heterogeneous wireless sensor network consists of wireless sensor nodes with
different abilities, such as different computing power and different initial
energy. We present in this paper a new scheme for maximizing heterogeneous WSN
lifetime. The proposed scheme employs two types of sensor nodes that are named
(consistent with IEEE 802.15.4 standard) Full Function Device (FFD) and Reduced
Function Device (RFD). The FFDs are the expensive sensor nodes with high power
and computational capabilities compared to the RFDs which are cheap sensors
with a limited power supply. The scheme divides the network into smaller
sub-networks (regions) that are built from sectors and tracks. The objective of
this research is to balance and reduce the communication load on RFDs, reduce
the delay, and increase the connectivity and lifetime, by using a limited
number of FFDs. We investigate the performance of our scheme via numerical
simulation and compare it to other related schemes that are presented for
homogeneous WSNs with chain topology, such as Pegasis, Epegasis and Chiron. In
addition to extending the lifetime, our scheme also results in reducing the
data transmission delay compared to the related schemes. Furthermore, the
scheme increases the network security and reduces the RFDs power consumption by
preventing the direct communication with the base station (BS). The FFD is the
communication bridge between RFDs and BS. The FFD communicate with the BS using
the one-hop approach or multi-hop approach through other FFDs.


title:
Component versus Superspace Approaches to D=4, N=1 Conformal
  Supergravity

abstract:
  The superspace formulation of N=1 conformal supergravity in four dimensions
is demonstrated to be equivalent to the conventional component field approach
based on the superconformal tensor calculus. The detailed correspondence
between two approaches is explicitly given for various quantities;
superconformal gauge fields, curvatures and curvature constraints, general
conformal multiplets and their transformation laws, and so on. In particular,
we carefully analyze the curvature constraints leading to the superconformal
algebra and also the superconformal gauge fixing leading to Poincare
supergravity since they look rather different between two approaches.


title:
Mass hierarchy sensitivity of medium baseline reactor neutrino
  experiments with multiple detectors

abstract:
  We report the neutrino mass hierarchy (MH) sensitivity of medium baseline
reactor neutrino experiments with multiple detectors. Sensitivity of
determining the MH can be significantly improved by adding a near detector and
combining both the near and far detectors. The size of the sensitivity
improvement is related to accuracy of the individual mass-splitting
measurements and requires strict control on the relative energy scale
uncertainty of the near and far detectors. We study the impact of both baseline
and target mass of the near detector on the combined sensitivity. A
figure-of-merit is defined to optimize the baseline and target mass of the near
detector and the optimal selections are $\sim$13~km and $\sim$4~kton
respectively for a far detector with the 20~kton target mass and 52.5~km
baseline. As typical examples of future medium baseline reactor neutrino
experiments, the optimal location and target mass of the near detector are
selected for JUNO and RENO-50. Finally, we discuss distinct effects of the
neutrino spectrum uncertainty for setups of a single detector and double
detectors, which indicate that the spectrum uncertainty can be well constrained
in the presence of the near detector.


title:
Non-affine horocycle orbit closures on strata of translation surfaces:
  new examples

abstract:
  We investigate specific examples of locally-defined real vector-fields on
strata of translation surfaces. Integrating SL(2,R)-loci of Veech surfaces
along these vector-fields yield interesting new examples of horocyle-invariant
ergodic measures. These measures are supported on closed immersed manifolds
with boundary that approach the boundary of strata in a novel way.


title: Rational maps between varieties associated to central simple algebras

abstract:
  In this paper we show that if two central simple $k$-algebras generate the
same cyclic subgroup in $\mathrm{Br}(k)$, then there are rational maps between
varieties associated to these algebras, such as Brauer--Severi varieties, norm
hypersurfaces and symmetric powers. In some cases we even have rational
embeddings. We also relate the obtained results to the Amitsur conjecture.


title:
Striped nanoscale phase separation at the metal-insulator transition of
  heteroepitaxial nickelates

abstract:
  Nucleation processes of mixed-phase states are an intrinsic characteristic of
first-order phase transitions, typically related to local symmetry breaking.
Direct observation of emerging mixed-phase regions in materials showing a
first-order metal-insulator transition (MIT) offers unique opportunities to
uncover their driving mechanism. Using photoemission electron microscopy, we
image the nanoscale formation and growth of insulating domains across the
temperature-driven MIT in NdNiO3 epitaxial thin films. Heteroepitaxy is found
to strongly determine the nanoscale nature of the phase transition, inducing
preferential formation of striped domains along the terraces of atomically flat
stepped surfaces. We show that the distribution of transition temperatures is
an intrinsic local property, set by surface morphology and stable across
multiple temperature cycles. Our data provides new insights into the MIT of
heteroepitaxial nickelates and points to a rich, nanoscale phenomenology in
this strongly correlated material.


title: Scalar triplet on a domain wall

abstract:
  We consider a model with a real scalar field with polynomial self-interaction
of the fourth degree and a coupled scalar triplet. We demonstrate that there is
an exact analytic solution in the form of a domain wall with a localised
configuration of the scalar triplet coupled to the wall. We study some
properties of this solution.


title: Are solar brightness variations faculae- or spot-dominated?

abstract:
  Regular spaceborne measurements have revealed that solar brightness varies on
multiple timescales, variations on timescales greater than a day being
attributed to surface magnetic field. Independently, ground-based and
spaceborne measurements suggest that Sun-like stars show a similar, but
significantly broader pattern of photometric variability.
  To understand whether the broader pattern of stellar variations is consistent
with the solar paradigm we assess relative contributions of faculae and spots
to solar magnetically-driven brightness variability. We investigate how the
solar brightness variability as well as its facular and spot contributions
depend on the wavelength, timescale of variability, and position of the
observer relative to the ecliptic plane.
  We perform calculations with the SATIRE model, which returns solar brightness
with daily cadence from solar disc area coverages of various magnetic features.
  Moving the observer away from the ecliptic plane increases the amplitude of
11-year variability as it would be seen in Str\"omgren $(b+y)/2$ photometry,
but decreases the amplitude of the rotational brightness variations as it would
appear in Kepler and CoRoT passbands. The spot and facular contributions to the
11-year solar variability in the Str\"omgren $(b+y)/2$ photometry almost fully
compensate each other so that the Sun appears anomalously quiet with respect to
its stellar cohort. Such a compensation does not occur on the rotational
timescale.
  The rotational solar brightness variability as it would appear in Kepler and
CoRoT passband from the ecliptic plane is spot-dominated but the relative
contribution of faculae increases for out-of-ecliptic viewing so that the
apparent brightness variations are faculae-dominated for inclinations less than
about $i=45^{\circ}$.


title: Pfaffian formula for $K$-theory of odd orthogonal Grassmannians

abstract:
  We prove a Pfaffain formula for the $K$-theory class of the degeneracy loci
in the bundle of odd maximal orthogonal Grassmannians.


title:
Root polytopes, Tutte polynomials, and a duality theorem for bipartite
  graphs

abstract:
  Let G be a connected bipartite graph with color classes E and V and root
polytope Q. Regarding the hypergraph (V,E) induced by G, we prove that its
interior polynomial is equivalent to the Ehrhart polynomial of Q, which in turn
is equivalent to the h-vector of any triangulation of Q. It follows that the
interior polynomials of (V,E) and its transpose (E,V) agree.
  When G is a complete bipartite graph, our result recovers a well known
hypergeometric identity due to Saalsch\"utz. It also implies that certain
extremal coefficients in the Homfly polynomial of a special alternating link
can be read off of an associated Floer homology group.


title:
Bayesian Optimization with Safety Constraints: Safe and Automatic
  Parameter Tuning in Robotics

abstract:
  Robotic algorithms typically depend on various parameters, the choice of
which significantly affects the robot's performance. While an initial guess for
the parameters may be obtained from dynamic models of the robot, parameters are
usually tuned manually on the real system to achieve the best performance.
Optimization algorithms, such as Bayesian optimization, have been used to
automate this process. However, these methods may evaluate unsafe parameters
during the optimization process that lead to safety-critical system failures.
Recently, a safe Bayesian optimization algorithm, called SafeOpt, has been
developed, which guarantees that the performance of the system never falls
below a critical value; that is, safety is defined based on the performance
function. However, coupling performance and safety is often not desirable in
robotics. For example, high-gain controllers might achieve low average tracking
error (performance), but can overshoot and violate input constraints. In this
paper, we present a generalized algorithm that allows for multiple safety
constraints separate from the objective. Given an initial set of safe
parameters, the algorithm maximizes performance but only evaluates parameters
that satisfy safety for all constraints with high probability. To this end, it
carefully explores the parameter space by exploiting regularity assumptions in
terms of a Gaussian process prior. Moreover, we show how context variables can
be used to safely transfer knowledge to new situations and tasks. We provide a
theoretical analysis and demonstrate that the proposed algorithm enables fast,
automatic, and safe optimization of tuning parameters in experiments on a
quadrotor vehicle.


title: Remarks on the inhomogeneous fractional nonlinear Schrodinger equation

abstract:
  Using a sharp Gagliardo-Nirenberg type inequality, well-posedness issues of
the initial value problem for a fractional inhomogeneous Schrodinger equation
are investigated.


title: Some conceptual issues in loop quantum cosmology

abstract:
  Loop quantum gravity is a mature theory. To proceed to explicit calculations
in cosmology, it is necessary to make assumptions and simplifications based on
the symmetries of the cosmological setting. Symmetry reduction is especially
critical when dealing with cosmological perturbations. The present article
reviews several approaches to the problem of building a consistent formalism
that describes the dynamics of perturbations on a quantum spacetime and tries
to address their respective strengths and weaknesses. We also review the main
open issues in loop quantum cosmology.


title: Exotic Higgs decays in U(1) extensions of the MSSM

abstract:
  We study the decays of the lightest CP-even Higgs boson into a pair of
pseudoscalar Higgs states within U(1)_N extensions of the MSSM.


title:
Horizon pressure from junction conditions for Schwarzschild and Rindler
  geometries

abstract:
  We assumed a stress tensor is necessary on the event horizon of a
Schwarzschild black hole or on the Rindler horizon for the Israel matching
conditions to be satisfied. We found the surface energy density $\rho_{s}$ is
vanishing but the surface pressure $p_{s}$ equals $1/16\pi l$ in both cases,
where $l$ is the proper distance from the horizon. The junction relations are
applied both for $r =$ const. and $T =$ const. surfaces, with the same results
for the surface parameters $\rho_{s}$ and $p_{s}$. We emphasize the nonstatic
feature of the spacetimes beyond the corresponding horizons.


title:
Combined analysis of the $\pi^-p\rightarrow K^0\Lambda$, $\eta n$
  reactions in a chiral quark model

abstract:
  A combined analysis of the reactions $\pi^-p\rightarrow K^0\Lambda$ and $\eta
n$ is carried out with a chiral quark model. The data in the center-of-mass
(c.m.) energy range from threshold up to $W\simeq 1.8$ GeV are reasonably
described. For $\pi^-p\rightarrow K^0\Lambda$, it is found that $N(1535)S_{11}$
and $N(1650)S_{11}$ paly crucial roles near threshold. The $N(1650)S_{11}$
resonance contributes to the reaction through configuration mixing with
$N(1535)S_{11}$. The constructive interference between $N(1535)S_{11}$ and
$N(1650)S_{11}$ is responsible for the peak structure around threshold in the
total cross section. The $n$-pole, $u$- and $t$-channel backgrounds provide
significant contributions to the reaction as well. While, for the
$\pi^-p\rightarrow \eta n$ process, the "first peak" in the total cross section
is dominant by $N(1535)S_{11}$, which has a sizeable destructive interference
with $N(1650)S_{11}$. Around $P_\pi \simeq $ 1.0 GeV/c ($W\simeq 1.7$ GeV),
there seems to be a small bump structure in the total cross section, which
might be explained by the interference between the $u$-channel and
$N(1650)S_{11}$. The $N(1520)D_{13}$ resonance notably affects the angle
distributions of the cross sections, although less effects are seen in the
total cross section. The role of $P$-wave state $N(1720)P_{13}$ should be
further confirmed by future experiments. If $N(1720)P_{13}$ has a narrow width
of $\Gamma\simeq 120$ MeV as found in our previous work by a study of the
$\pi^0$ photoproduction processes, obvious evidence should be seen in the
$\pi^-p\rightarrow K^0\Lambda$ and $\eta n$ processes as well.


title: Flat matrix models for quantum permutation groups

abstract:
  We study the matrix models $\pi:C(S_N^+)\to M_N(C(X))$ which are flat, in the
sense that the standard generators of $C(S_N^+)$ are mapped to rank 1
projections. Our first result is a generalization of the Pauli matrix
construction at $N=4$, using finite groups and 2-cocycles. Our second result is
the construction of a universal representation of $C(S_N^+)$, inspired from the
Sinkhorn algorithm, that we conjecture to be inner faithful.


title: A JKO splitting scheme for Kantorovich-Fisher-Rao gradient flows

abstract:
  In this article we set up a splitting variant of the JKO scheme in order to
handle gradient flows with respect to the Kantorovich-Fisher-Rao metric,
recently introduced and defined on the space of positive Radon measure with
varying masses. We perform successively a time step for the quadratic
Wasserstein/Monge-Kantorovich distance, and then for the Hellinger/Fisher-Rao
distance. Exploiting some inf-convolution structure of the metric we show
convergence of the whole process for the standard class of energy functionals
under suitable compactness assumptions, and investigate in details the case of
internal energies. The interest is double: On the one hand we prove existence
of weak solutions for a certain class of reaction-advection-diffusion
equations, and on the other hand this process is constructive and well adapted
to available numerical solvers.


title:
Intense THz source based on BNA organic crystal pumped at Ti:Sapphire
  wavelength

abstract:
  We report on high energy terahertz pulses by optical rectification (OR) in
the organic crystal N-benzyl-2-methyl-4-nitroaniline (BNA) directly pumped by a
conventional Ti:Sapphire (Ti:Sa) amplifier. The simple scheme provides an
optical to terahertz conversion efficiency of 0.25% when pumped by a collimated
laser pulses with duration of 50 fs and central wavelength of 800nm. The
generated radiation spans frequencies between 0.2 and 3 THz. We measured the
damage threshold as well as the dependency of the conversion efficiency on the
pump fluence, pump wavelength, and pulse duration.


title:
Energy-momentum tensors in linearized Einstein's theory and massive
  gravity: The question of uniqueness

abstract:
  The question of the uniqueness of energy-momentum tensors in the linearized
general relativity and in the linear massive gravity is analyzed without using
variational techniques. We start from a natural ansatz for the form of the
tensor (for example, that it is a linear combination of the terms quadratic in
the first derivatives), and require it to be conserved as a consequence of
field equations. In the case of the linear gravity in a general gauge we find a
four-parametric system of conserved second-rank tensors which contains a unique
symmetric tensor. This turns out to be the linearized Landau-Lifshitz
pseudotensor employed often in full general relativity. We elucidate the
relation of the four-parametric system to the expression proposed recently by
Butcher et al. "on physical grounds" in harmonic gauge, and we show that the
results coincide in the case of high-frequency waves in vacuum after a suitable
averaging. In the massive gravity we show how one can arrive at the expression
which coincides with the "generalized linear symmetric Landau-Lifshitz" tensor.
However, there exists another uniquely given simpler symmetric tensor which can
be obtained by adding the divergence of a suitable superpotential to the
canonical energy-momentum tensor following from the Fierz-Pauli action. In
contrast to the symmetric tensor derived by the Belinfante procedure which
involves the second derivatives of the field variables, this expression
contains only the field and its first derivatives. It is simpler than the
generalized Landau-Lifshitz tensor but both yield the same total quantities
since they differ by the divergence of a superpotential. We also discuss the
role of the gauge conditions in the proofs of the uniqueness. In the Appendix,
the use of the symbolic tensor manipulation software Cadabra is briefly
described.


title:
Implications of the Tentative Association between GW150914 and a {\it
  Fermi}-GBM Transient

abstract:
  The merger-driven Gamma-ray Bursts (GRBs) and their associated gravitational
wave (GW) radiation, if both successfully detected, have some far-reaching
implications, including for instance: (i) The statistical comparison of the
physical properties of the short/long-short GRBs with and without GW detection
can test the general origin model; (ii) Revealing the physical processes taking
place at the central engine; (iii) Measuring the velocity of the Gravitational
wave directly/accurately. In this work we discuss these implications in the
case of possible association of GW150914/ GBM transient 150914. We compared GBM
transient 150914 with other SGRBs and found that such an event {may be} a
distinct outlier in some statistical diagrams, possibly due to its specific
binary-black-hole merger origin. However, the presence of a "new" group of
SGRBs with "unusual" physical parameters is also possible. If the outflow of
GBM transient 150914 was launched by the accretion onto the nascent black hole,
the magnetic activity rather than the neutrino process is likely responsible
for the energy extraction and the accretion disk mass is estimated to be $\sim
10^{-5}~M_\odot$. The GW150914/GBM transient 150914 association, {if confirmed,
would} provide the first opportunity to directly measure the GW velocity and
its departure from the speed of the light {should be within} a factor of $\sim
10^{-17}$.


title: Geodesic-light-cone coordinates and the Bianchi I spacetime

abstract:
  The geodesic-light-cone (GLC) coordinates are a useful tool to analyse light
propagation and observations in cosmological models. In this article, we
propose a detailed, pedagogical, and rigorous introduction to this coordinate
system, explore its gauge degrees of freedom, and emphasize its interest when
geometric optics is at stake. We then apply the GLC formalism to the
homogeneous and anisotropic Bianchi I cosmology. More than a simple
illustration, this application (i) allows us to show that the Weinberg
conjecture according to which gravitational lensing does not affect the proper
area of constant-redshift surfaces is significantly violated in a globally
anisotropic universe; and (ii) offers a glimpse into new ways to constrain
cosmic isotropy from the Hubble diagram.


title: On Symplectic Dynamics

abstract:
  This paper continues to carry out a foundational study of Banyaga topologies
of a closed symplectic manifold [3]. Our intension in writing this paper is to
provide several symplectic analogues of some results found in the study of
Hamiltonian dynamics. Especially, without appealing to the positivity of the
symplectic displacement energy, we point out the impact of the $L^\infty$
version of Banyaga Hofer-like metric in the investigation of the symplectic
nature of the $C^0-$limit of a sequence of symplectic maps. This result is the
symplectic analogue of a result that was proved in Hofer-Zehnder [8] (for
compactly supported Hamiltonian diffeomorphisms on $\mathbb{R}^{2n}$), and then
reformulated in Oh-M\"{u}ller [10] for Hamiltonian diffeomorphisms in general.
Furthermore, we extend to symplectic isotopies the regularization procedure for
Hamiltonian paths introduced in Polterovich [11], and then we use it to prove
the equality between the two versions of Banyaga Hofer-like norms defined on
the identity component in the group of symplectomorphisms. This result was
announced in [2]. It shows the uniqueness of Banyaga Hofer-like geometry, and
then yields the symplectic analogue of a result that was proved in Polterovich
[11]. Finally, we elaborate the symplectic analogues of some approximation
results found in Oh-M\"{u}ller [10], and make some remarks on flux theory.


title: Parallel Polarization State Generation

abstract:
  The control of polarization, an essential property of light, is of wide
scientific and technological interest. The general problem of generating
arbitrary time-varying states of polarization (SOP) has always been
mathematically formulated by a series of linear transformations, i.e. a product
of matrices, imposing a serial architecture. Here we show a parallel
architecture described by a sum of matrices. The theory is experimentally
demonstrated by modulating spatially-separated polarization components of a
laser using a digital micromirror device that are subsequently beam combined.
This method greatly expands the parameter space for engineering devices that
control polarization. Consequently, performance characteristics, such as speed,
stability, and spectral range, are entirely dictated by the technologies of
optical intensity modulation, including absorption, reflection, emission, and
scattering. This opens up important prospects for polarization state generation
(PSG) with unique performance characteristics and applications in spectroscopic
ellipsometry, spectropolarimetry, communications, imaging, and security.


title:
Active control of surface plasmon resonance in MoS2-Ag hybrid
  nanostructures

abstract:
  Molybdenum disulfide (MoS2) monolayers have attracted much attention for
their novel optical properties and efficient light-matter interactions. When
excited by incident laser, the optical response of MoS2 monolayers was
effectively modified by elementary photo-excited excitons owing to their large
exciton binding energy, which can be facilitated for the optical-controllable
exciton-plasmon interactions. Inspired by this concept, we experimentally
investigated active light control of surface plasmon resonance (SPR) in MoS2-Ag
hybrid nanostructures. The white light spectra of SPR were gradually
red-shifted by increasing laser power, which was distinctly different from the
one of bare Ag nanostructure. This spectroscopic tunability can be further
controlled by near-field coupling strength and polarization state of light, and
selectively applied to the control of plasmonic dark mode. An analytical
Lorentz model for photo-excited excitons induced modulation of MoS2 dielectric
function was developed to explain the insight physics of this SPR tunability.
Our study opens new possibilities to the development of all-optical controlled
nanophotonic devices based on 2D materials.


title: Closedness and invertibility for the sum of two closed operators

abstract:
  We show a Kalton-Weis type theorem for the general case of non-commuting
operators. More precisely, we consider sums of two possibly non-commuting
linear operators defined in a Banach space such that one of the operators
admits a bounded $H^\infty$-calculus, the resolvent of the other one satisfies
some weaker boundedness condition and the commutator of their resolvents has
certain decay behavior with respect to the spectral parameters. Under this
consideration, we show that the sum is closed and that after a sufficiently
large positive shift it becomes invertible, and moreover sectorial. As an
application we recover a classical result on the existence, uniqueness and
maximal $L^{p}$-regularity for solutions of the abstract linear non-autonomous
parabolic problem.


title:
Mediation with near insolvent defaulting suppliers: a linear
  optimisation model to find an optimal outcome

abstract:
  This paper presents a model to describe contractual dispute resolution by
mediation in situations where a defaulting supplier is near insolvent. While
each party has internal constraints, and if alternate performances are
available, such as more costly alternative goods, the proposed approach allows
the mediator to find an optimal solution. The notion of optimality is presented
as adherence to the initial contract, therefore optimising a value function for
the non defaulting party. The proposed model includes describing the evolution
over time of each party's perceived constraints using a phasor like approach
with a modulation to the core constraints phasing out of the real part and
phasing in the imaginary part of complex numbers. The offers related to
alternative performances by the defaulting party are modelled by a Gompertz
function, being an exponential learning curve of the supplier in regards to the
reaction to its offers, limited by another exponential function when
approaching its internal constraints. Furthermore, the model takes into account
the discount associated to the delay in the delivery time of the alternative
performances.


title: Quantitative homogenization of degenerate random environments

abstract:
  We study discrete linear divergence-form operators with random coefficients,
also known as the random conductance model. We assume that the conductances are
bounded, independent and stationary; the law of a conductance may depend on the
orientation of the associated edge. We give a simple necessary and sufficient
condition for the relaxation of the environment seen by the particle to be
diffusive, in the sense of every polynomial moment. As a consequence, we derive
polynomial moment estimates on the corrector.


title: Observability of Sensorless Electric Drives

abstract:
  Electric drives control without shaft sensors has been an active research
topic for almost three decades. It consists of estimating the rotor speed
and/or position from the currents and voltages measurement. This paper deals
with the observability conditions of electric drives in view of sensorless
control. The models of such systems are strongly nonlinear. For this reason, a
local observability approach is applied to analyze the deteriorated performance
of sensorless drives in some operating conditions. The validity of the
observability conditions is confirmed by numerical simulations and experimental
data, using an extended Kalman filter as observer.


title:
Footprint Characteristics Revised for Field-Scale Soil Moisture
  Monitoring with Cosmic-Ray Neutrons

abstract:
  Cosmic-ray neutron probes are widely used to monitor environmental water
content near the surface. The method averages over tens of hectares and is
unrivaled in serving representative data for agriculture and hydrological
models at the hectometer scale. Recent experiments, however, indicate that the
sensor response to environmental heterogeneity is not fully understood.
Knowledge of the support volume is a prerequisite for the proper interpretation
and validation of hydrogeophysical data. In a previous study, several physical
simplifications have been introduced into a neutron transport model in order to
derive the characteristics of the cosmic-ray probe's footprint. We utilize a
refined source and energy spectrum for cosmic-ray neutrons and simulate their
response to a variety of environmental conditions. Results indicate that the
method is particularly sensitive to soil moisture in the first tens of meters
around the probe, whereas the radial weights are changing dynamically with
ambient water. The footprint radius ranges from 130 to 240 m depending on air
humidity, soil moisture and vegetation. The moisture-dependent penetration
depth of 15 to 83 cm decreases exponentially with distance to the sensor.
However, the footprint circle remains almost isotropic in complex terrain with
nearby rivers, roads or hill slopes. Our findings suggest that a dynamically
weighted average of point measurements is essential for accurate calibration
and validation. The new insights will have important impact on signal
interpretation, sensor installation, data interpolation from mobile surveys,
and the choice of appropriate resolutions for data assimilation into
hydrological models.


title:
Binding of the immunomodulatory drug Bz-423 to mitochondrial FoF1-ATP
  synthase in living cells by FRET acceptor photobleaching

abstract:
  Bz-423 is a promising new drug for treatment of autoimmune diseases. This
small molecule binds to subunit OSCP of the mitochondrial enzyme FoF1-ATP
synthase and modulates its catalytic activities. We investigate the binding of
Bz-423 to mitochondria in living cells and how subunit rotation in FoF1-ATP
synthase, i.e. the mechanochemical mechanism of this enzyme, is affected by
Bz-423. Therefore, the enzyme was marked selectively by genetic fusion with the
fluorescent protein EGFP to the C terminus of subunit gamma. Imaging the
threedimensional arrangement of mitochondria in living yeast cells was possible
at superresolution using structured illumination microscopy, SIM. We measured
uptake and binding of a Cy5-labeled Bz-423 derivative to mitochondrial FoF1-ATP
synthase in living yeast cells using FRET acceptor photobleaching microscopy.
Our data confirmed the binding of Cy5-labeled Bz-423 to the top of the F1
domain of the enzyme in mitochondria of living Saccharomyces cerevisiae cells.


title:
Electrical Transport Properties in ZnO Bulk, c/ZnO and ZnMgO/ZnO/ZnMgO
  Heterostructures

abstract:
  In this paper, the reported experimental data in [Sci. Rep., 2012, 2, 533]
related to electrical transport properties in bulk ZnO, ZnMgO/ZnO, and
ZnMgO/ZnO/ZnMgO single and double heterostructures were analyzed quantitatively
and the most important scattering parameters for controlling electron
concentration and electron mobility were obtained. Treatment of intrinsic
mechanisms included polar-optical phonon scattering, piezoelectric scattering
and acoustic deformation potential scattering. For extrinsic mechanisms,
ionized impurity, dislocation scattering, and strain-induced fields were
included. For bulk ZnO, the reported experimental data were corrected for
removing the effects of a degenerate layer at the ZnO/sapphire interface via a
two layer Hall effect model. Also, donor density, acceptor density and donor
activation energy were determined via the charge balance equation. This sample
exhibited hopping conduction below 50K and dislocation scattering closely
controlled electron mobility closely. The obtained results indicated that the
enhancement of electron mobility in double sample, compared with the single
one, can be attributed to the reduction of dislocation density, two dimensional
impurity density in the potential well due to background impurities, and/or
interface charge and strain-induced fields, which can be related to better
electron confinement in the channel and enhancement in the sheet carrier
concentration of 2DEG in this sample.


title: Modernity of Halphen's variations on a theme of Monge

abstract:
  We construct a Z_3-slice to the natural action of PGL(V) on the variety of
smooth arcs in the projective space P(V).


title: Large-Scale Reasoning with OWL

abstract:
  With the growth of the Semantic Web in size and importance, more and more
knowledge is stored in machine-readable formats such as the Web Ontology
Language OWL. This paper outlines common approaches for efficient reasoning on
large-scale data consisting of billions ($10^9$) of triples. Therefore, OWL and
its sublanguages, as well as forward and backward chaining techniques are
presented. The WebPIE reasoner is discussed in detail as an example for forward
chaining using MapReduce for materialisation. Moreover, the QueryPIE reasoner
is presented as a backward chaining/hybrid approach which uses query rewriting.
Furthermore, an overview on other reasoners is given such as OWLIM and TrOWL.


title: Generalization Properties of Learning with Random Features

abstract:
  We study the generalization properties of ridge regression with random
features in the statistical learning framework. We show for the first time that
$O(1/\sqrt{n})$ learning bounds can be achieved with only $O(\sqrt{n}\log n)$
random features rather than $O({n})$ as suggested by previous results. Further,
we prove faster learning rates and show that they might require more random
features, unless they are sampled according to a possibly problem dependent
distribution. Our results shed light on the statistical computational
trade-offs in large scale kernelized learning, showing the potential
effectiveness of random features in reducing the computational complexity while
keeping optimal generalization properties.


title:
Modeling Defects, Shape Evolution, and Programmed Auto-origami in Liquid
  Crystal Elastomers

abstract:
  Liquid crystal elastomers represent a novel class of programmable
shape-transforming materials whose shape change trajectory is encoded in the
material's nematic director field. Using three-dimensional nonlinear finite
element elastodynamics simulation, we model a variety of different actuation
geometries and device designs: thin films containing topological defects,
patterns that induce formation of folds and twists, and a bas-relief structure.
The inclusion of finite bending energy in the simulation model reveals features
of actuation trajectory that may be absent when bending energy is neglected. We
examine geometries with a director pattern uniform through the film thickness
encoding multiple regions of positive Gaussian curvature. Simulations indicate
that heating such a system uniformly produces a disordered state with curved
regions emerging randomly in both directions due to the film's up-down
symmetry. By contrast, applying a thermal gradient by heating the material
first on one side breaks up-down symmetry and results in a deterministic
trajectory producing a more ordered final shape. We demonstrate that a folding
zone design containing cut-out areas accommodates transverse displacements
without warping or buckling; and demonstrate that bas-relief and more complex
bent-twisted structures can be assembled by combining simple design motifs.


title: Viewpoint: The First Sounds of Merging Black Holes

abstract:
  Gravitational waves emitted by the merger of two black holes have been
detected, setting the course for a new era of observational astrophysics.


title:
On infinite effectivity of motivic spectra and the vanishing of their
  motives

abstract:
  This paper is dedicated to the study of the kernel of the "compact
motivization" functor $M_{k}^c:SH^c(k)\to DM^c(k)$ (i.e., we try to describe
those compact objects of $SH(k)$ whose associated motives vanish. Moreover, we
study the question when the $m$-connectivity of $M^c_{k}(E)$ ensures the
$m$-connectivity of $E$ itself (with respect to the corresponding homotopy
t-structures). We prove that the kernel of $M_{k}^c$ vanishes and the
corresponding "connectivity detection" statement is also valid if and only if
$k$ is a non-orderable field; this is an easy consequence of the corresponding
results of T. Bachmann (who considered the case where the $2$-adic
cohomological dimension of $k$ is finite). We also sketch a deduction of these
statements from the "slice-convergence" results of M. Levine. Moreover, for a
general $k$ we prove that this kernel does not contain any $2$-torsion; the
author also suspects that all its elements are odd torsion. Besides we prove
that the kernel in question consists exactly of "infinitely effective" (in the
sense of Voevodsky's slice filtration) objects of $SH^c(k)$ (assuming that the
exponential characteristic of $k$ is inverted in the coefficient ring).
  These result allow (following another idea of Bachmann) to carry over his
results on the tensor invertibility of certain motives of affine quadrics to
the corresponding motivic spectra whenever $k$ is non-orderable. We also
generalize a theorem of A. Asok.


title: Subgraph Counting: Color Coding Beyond Trees

abstract:
  The problem of counting occurrences of query graphs in a large data graph,
known as subgraph counting, is fundamental to several domains such as genomics
and social network analysis. Many important special cases (e.g. triangle
counting) have received significant attention. Color coding is a very general
and powerful algorithmic technique for subgraph counting. Color coding has been
shown to be effective in several applications, but scalable implementations are
only known for the special case of {\em tree queries} (i.e. queries of
treewidth one).
  In this paper we present the first efficient distributed implementation for
color coding that goes beyond tree queries: our algorithm applies to any query
graph of treewidth $2$. Since tree queries can be solved in time linear in the
size of the data graph, our contribution is the first step into the realm of
colour coding for queries that require superlinear running time in the worst
case. This superlinear complexity leads to significant load balancing problems
on graphs with heavy tailed degree distributions. Our algorithm structures the
computation to work around high degree nodes in the data graph, and achieves
very good runtime and scalability on a diverse collection of data and query
graph pairs as a result. We also provide theoretical analysis of our
algorithmic techniques, showing asymptotic improvements in runtime on random
graphs with power law degree distributions, a popular model for real world
graphs.


title: Quantum scattering theory of Fock states in high-dimensional spaces

abstract:
  A quantum scattering theory is developed for Fock states scattered by
two-level systems in the free space. Compared to existing scattering theories
that treat incident light semi-classically, the theory fully quantizes the
incident light as Fock states. This non-perturbative method provides exact
scattering matrix.


title: From Doob's maximal identity to Azema supermartingale

abstract:
  We characterize the random times $\rho$ whose Azema supermartingales $Z^\rho$
take the form $Z^\rho=U/U^*$ for some non negative local martingales $U$
starting from 1 vanishing at infinity, where $U^*$ denotes the running maximum
process of $U$.


title: Ramsey's theorem for singletons and strong computable reducibility

abstract:
  We answer a question posed by Hirschfeldt and Jockusch by showing that
whenever $k > \ell$, Ramsey's theorem for singletons and $k$-colorings,
$\mathsf{RT}^1_k$, is not strongly computably reducible to the stable Ramsey's
theorem for $\ell$-colorings, $\mathsf{SRT}^2_\ell$. Our proof actually
establishes the following considerably stronger fact: given $k > \ell$, there
is a coloring $c : \omega \to k$ such that for every stable coloring $d :
[\omega]^2 \to \ell$ (computable from $c$ or not), there is an infinite
homogeneous set $H$ for $d$ that computes no infinite homogeneous set for $c$.
This also answers a separate question of Dzhafarov, as it follows that the
cohesive principle, $\mathsf{COH}$, is not strongly computably reducible to the
stable Ramsey's theorem for all colorings, $\mathsf{SRT}^2_{<\infty}$. The
latter is the strongest partial result to date in the direction of giving a
negative answer to the longstanding open question of whether $\mathsf{COH}$ is
implied by the stable Ramsey's theorem in $\omega$-models of $\mathsf{RCA}_0$.


title:
Bounds on the Maximal Minimum Distance of Linear Locally Repairable
  Codes

abstract:
  Locally repairable codes (LRCs) are error correcting codes used in
distributed data storage. Besides a global level, they enable errors to be
corrected locally, reducing the need for communication between storage nodes.
There is a close connection between almost affine LRCs and matroid theory which
can be utilized to construct good LRCs and derive bounds on their performance.
  A generalized Singleton bound for linear LRCs with parameters
$(n,k,d,r,\delta)$ was given in [N. Prakash et al., "Optimal Linear Codes with
a Local-Error-Correction Property", IEEE Int. Symp. Inf. Theory]. In this
paper, a LRC achieving this bound is called perfect. Results on the existence
and nonexistence of linear perfect $(n,k,d,r,\delta)$-LRCs were given in [W.
Song et al., "Optimal locally repairable codes", IEEE J. Sel. Areas Comm.].
Using matroid theory, these existence and nonexistence results were later
strengthened in [T. Westerb\"ack et al., "On the Combinatorics of Locally
Repairable Codes", Arxiv: 1501.00153], which also provided a general lower
bound on the maximal achievable minimum distance $d_{\rm{max}}(n,k,r,\delta)$
that a linear LRC with parameters $(n,k,r,\delta)$ can have. This article
expands the class of parameters $(n,k,d,r,\delta)$ for which there exist
perfect linear LRCs and improves the lower bound for
$d_{\rm{max}}(n,k,r,\delta)$. Further, this bound is proved to be optimal for
the class of matroids that is used to derive the existence bounds of linear
LRCs.


title:
Casimir interaction of rod-like particles in a two-dimensional critical
  system

abstract:
  We consider the fluctuation-induced interaction of two thin, rod-like
particles or "needles" immersed in a two-dimensional critical fluid of Ising
symmetry right at the critical point. Conformally mapping the plane containing
the needles onto a simpler geometry in which the stress tensor is known, we
analyze the force and torque between needles of arbitrary length, separation,
and orientation. For infinite and semi-infinite needles we utilize the mapping
of the plane bounded by the needles onto the half plane, and for two needles of
finite length the mapping onto an annulus. For semi-infinite and infinite
needles the force is expressed in terms of elementary functions, and we also
obtain analytical results for the force and torque between needles of finite
length with separation much greater than their length. Evaluating formulas in
our approach numerically for several needle geometries and surface universality
classes, we study the full crossover from small to large values of the
separation to length ratio. In these two limits the numerical results agree
with results for infinitely long needles and with predictions of the
small-particle operator expansion, respectively.


title: Surprising properties of dropout in deep networks

abstract:
  We analyze dropout in deep networks with rectified linear units and the
quadratic loss. Our results expose surprising differences between the behavior
of dropout and more traditional regularizers like weight decay. For example, on
some simple data sets dropout training produces negative weights even though
the output is the sum of the inputs. This provides a counterpoint to the
suggestion that dropout discourages co-adaptation of weights. We also show that
the dropout penalty can grow exponentially in the depth of the network while
the weight-decay penalty remains essentially linear, and that dropout is
insensitive to various re-scalings of the input features, outputs, and network
weights. This last insensitivity implies that there are no isolated local
minima of the dropout training criterion. Our work uncovers new properties of
dropout, extends our understanding of why dropout succeeds, and lays the
foundation for further progress.

categories: cs.LG cs.AI cs.NE math.ST stat.ML stat.TH


title: Benefits of depth in neural networks

abstract:
  For any positive integer $k$, there exist neural networks with $\Theta(k^3)$
layers, $\Theta(1)$ nodes per layer, and $\Theta(1)$ distinct parameters which
can not be approximated by networks with $\mathcal{O}(k)$ layers unless they
are exponentially large --- they must possess $\Omega(2^k)$ nodes. This result
is proved here for a class of nodes termed "semi-algebraic gates" which
includes the common choices of ReLU, maximum, indicator, and piecewise
polynomial functions, therefore establishing benefits of depth against not just
standard networks with ReLU gates, but also convolutional networks with ReLU
and maximization gates, sum-product networks, and boosted decision trees (in
this last case with a stronger separation: $\Omega(2^{k^3})$ total tree nodes
are required).


title:
Constraints on the original ejection velocity fields of asteroid
  families

abstract:
  Asteroid families form as a result of large-scale collisions among main belt
asteroids. The orbital distribution of fragments after a family-forming impact
could inform us about their ejection velocities. Unfortunately, however, orbits
dynamically evolve by a number of effects, including the Yarkovsky drift,
chaotic diffusion, and gravitational encounters with massive asteroids, such
that it is difficult to infer the ejection velocities eons after each family's
formation. Here we analyze the inclination distribution of asteroid families,
because proper inclination can remain constant over long time intervals, and
could help us to understand the distribution of the component of the ejection
velocity that is perpendicular to the orbital plane ($v_{W}$). From modeling
the initial breakup, we find that the distribution of $v_{W}$ of the fragments,
which manage to escape the parent body's gravity, should be more peaked than a
Gaussian distribution (i.e., be leptokurtic) even if the initial distribution
was Gaussian. We surveyed known asteroid families for signs of a peaked
distribution of $v_{W}$ using a statistical measure of the distribution
peakedness or flatness known as kurtosis. We identified eight families whose
$v_{W}$ distribution is significantly leptokurtic. These cases (e.g. the
Koronis family) are located in dynamically quiet regions of the main belt,
where, presumably, the initial distribution of $v_{W}$ was not modified by
subsequent orbital evolution. We suggest that, in these cases, the inclination
distribution can be used to obtain interesting information about the original
ejection velocity field.


title: Aperiodic Crosscorrelation of Sequences Derived from Characters

abstract:
  It is shown that pairs of maximal linear recursive sequences (m-sequences)
typically have mean square aperiodic crosscorrelation on par with that of
random sequences, but that if one takes a pair of m-sequences where one is the
reverse of the other, and shifts them appropriately, one can get significantly
lower mean square aperiodic crosscorrelation. Sequence pairs with even lower
mean square aperiodic crosscorrelation are constructed by taking a Legendre
sequence, cyclically shifting it, and then cutting it (approximately) in half
and using the halves as the sequences of the pair. In some of these
constructions, the mean square aperiodic crosscorrelation can be lowered
further if one truncates or periodically extends (appends) the sequences. Exact
asymptotic formulae for mean squared aperiodic crosscorrelation are proved for
sequences derived from additive characters (including m-sequences and modified
versions thereof) and multiplicative characters (including Legendre sequences
and their relatives). Data is presented that shows that sequences of modest
length have performance that closely approximates the asymptotic formulae.


title: Fermi-LAT Observations of the LIGO event GW150914

abstract:
  The Fermi Large Area Telescope (LAT) has an instantaneous field of view
covering $\sim 1/5$ of the sky and completes a survey of the full sky every ~3
hours. It provides a continuous, all-sky survey of high-energy gamma-rays,
enabling searches for transient phenomena over timescales from milliseconds to
years. Among these phenomena could be electromagnetic counterparts to
gravitational wave sources. In this paper, we present a detailed study of the
LAT observations relevant to Laser Interferometer Gravitational-wave
Observatory (LIGO) event GW150904 (Abbott et al. 2016), which is the first
direct detection of gravitational waves and has been interpreted as due to
coalescence of two stellar-mass black holes. The localization region for
GW150904 was outside the LAT field of view at the time of the gravitational
wave signal. However, as part of routine survey observations, the LAT observed
the entire LIGO localization region within ~70 minutes of the trigger, and thus
enabled a comprehensive search for a gamma-ray counterpart to GW150904. The
study of the LAT data presented here did not find any potential counterparts to
GW150904, but it did provide limits on the presence of a transient counterpart
above 100 MeV on timescales of hours to days over the entire GW150904
localization region.


title: Convolutional Tables Ensemble: classification in microseconds

abstract:
  We study classifiers operating under severe classification time constraints,
corresponding to 1-1000 CPU microseconds, using Convolutional Tables Ensemble
(CTE), an inherently fast architecture for object category recognition. The
architecture is based on convolutionally-applied sparse feature extraction,
using trees or ferns, and a linear voting layer. Several structure and
optimization variants are considered, including novel decision functions, tree
learning algorithm, and distillation from CNN to CTE architecture. Accuracy
improvements of 24-45% over related art of similar speed are demonstrated on
standard object recognition benchmarks. Using Pareto speed-accuracy curves, we
show that CTE can provide better accuracy than Convolutional Neural Networks
(CNN) for a certain range of classification time constraints, or alternatively
provide similar error rates with 5-200X speedup.


title: Tracking Influential Nodes in Dynamic Networks

abstract:
  In this paper, we tackle a challenging problem inherent in a series of
applications: tracking the influential nodes in dynamic networks. Specifically,
we model a dynamic network as a stream of edge weight updates. This general
model embraces many practical scenarios as special cases, such as edge and node
insertions, deletions as well as evolving weighted graphs. Under the popularly
adopted linear threshold model and independent cascade model, we consider two
essential versions of the problem: finding the nodes whose influences passing a
user specified threshold and finding the top-$k$ most influential nodes. Our
key idea is to use the polling-based methods and maintain a sample of random RR
sets so that we can approximate the influence of nodes with provable quality
guarantees. We develop an efficient algorithm that incrementally updates the
sample random RR sets against network changes. We also design methods to
determine the proper sample sizes for the two versions of the problem so that
we can provide strong quality guarantees and, at the same time, be efficient in
both space and time. In addition to the thorough theoretical results, our
experimental results on $5$ real network data sets clearly demonstrate the
effectiveness and efficiency of our algorithms.


title:
Characterizing the original ejection velocity field of the Koronis
  family

abstract:
  An asteroid family forms as a result of a collision between an impactor and a
parent body. The fragments with ejection speeds higher than the escape velocity
from the parent body can escape its gravitational pull. The cloud of escaping
debris can be identified by the proximity of orbits in proper element, or
frequency, domains. Obtaining estimates of the original ejection speed can
provide valuable constraints on the physical processes occurring during
collision, and used to calibrate impact simulations. Unfortunately, proper
elements of asteroids families are modified by gravitational and
non-gravitational effects, such as resonant dynamics, encounters with massive
bodies, and the Yarkovsky effect, such that information on the original
ejection speeds is often lost, especially for older, more evolved families.
  It has been recently suggested that the distribution in proper inclination of
the Koronis family may have not been significantly perturbed by local dynamics,
and that information on the component of the ejection velocity that is
perpendicular to the orbital plane ($v_W$), may still be available, at least in
part. In this work we estimate the magnitude of the original ejection velocity
speeds of Koronis members using the observed distribution in proper
eccentricity and inclination, and accounting for the spread caused by dynamical
effects. Our results show that i) the spread in the original ejection speeds
is, to within a 15% error, inversely proportional to the fragment size, and ii)
the minimum ejection velocity is of the order of 50 m/s, with larger values
possible depending on the orbital configuration at the break-up.


title: Flat lens for seismic waves

abstract:
  A prerequisite for achieving seismic invisibility is to demonstrate the
ability of civil engineers to control seismic waves with artificially
structured soils. We carry out large-scale field tests with a structured soil
made of a grid consisting of cylindrical and vertical holes in the ground and a
low frequency artificial source (< 10 Hz). This allows the identification of a
distribution of energy inside the grid, which can be interpreted as the
consequence of an effective negative refraction index. Such a flat lens
reminiscent of what Veselago and Pendry envisioned for light opens avenues in
seismic metamaterials to counteract the most devastating components of seismic
signals.


title:
Secure Data Storage Structure and Privacy-Preserving Mobile Search
  Scheme for Public Safety Networks

abstract:
  In a Public Safety (PS) situation, agents may require critical and personally
identifiable information. Therefore, not only does context and location-aware
information need to be available, but also the privacy of such information
should be preserved. Existing solutions do not address such a problem in a PS
environment. This paper proposes a framework in which anonymized Personal
Information (PI) is accessible to authorized public safety agents under a PS
circumstance. In particular, we propose a secure data storage structure along
with privacy-preserving mobile search framework, suitable for Public Safety
Networks (PSNs). As a result, availability and privacy of PI are achieved
simultaneously. However, the design of such a framework encounters substantial
challenges, including scalability, reliability of the data, computation and
communication and storage efficiency, etc. We leverage Secure Indexing (SI)
methods and modify Bloom Filters (BFs) to create a secure data storage
structure to store encrypted meta-data. As a result, our construction enables
secure and privacy-preserving multi-keyword search capability. In addition, our
system scales very well, maintains availability of data, imposes minimum delay,
and has affordable storage overhead. We provide extensive security analysis,
simulation studies, and performance comparison with the state-of-the-art
solutions to demonstrate the efficiency and effectiveness of the proposed
approach. To the best of our knowledge, this work is the first to address such
issues in the context of PSNs.


title: Sylow theorems for $\infty$-groups

abstract:
  Viewing Kan complexes as $\infty$-groupoids implies that pointed and
connected Kan complexes are to be viewed as $\infty$-groups. A fundamental
question is then: to what extent can one "do group theory" with these objects?
In this paper we develop a notion of a finite $\infty$-group: an $\infty$-group
with finitely many non-trivial homotopy groups which are all finite. We prove a
homotopical analog of the Sylow theorems for finite $\infty$-groups. We derive
two corollaries: the first is a homotopical analog of the Burnside's fixed
point lemma for $p$-groups and the second is a "group-theoretic"
characterization of (finite) nilpotent spaces.


title: Integral Inequalities in Thermodynamics

abstract:
  Thermodynamic systems involving reversible and non-reversible heat transfer
are used to derive integral inequalities expected from the Second of Law of
Thermodynamics. Then, the inequalities are proved and generalized to higher
dimensions with intended application of being used as a quick way of generating
numerous other inequalities such as the Weighted Means Inequality. The proofs
also serve as a way of establishing the equivalence of the Planck's statement
of the Second Law and the positivity of specific heats.


title: Minimum Storage Regenerating Codes For All Parameters

abstract:
  Regenerating codes for distributed storage have attracted much research
interest in the past decade. Such codes trade the bandwidth needed to repair a
failed node with the overall amount of data stored in the network. Minimum
storage regenerating (MSR) codes are an important class of optimal regenerating
codes that minimize (first) the amount of data stored per node and (then) the
repair bandwidth. Specifically, an $[n,k,d]$-$(\alpha)$ MSR code $\mathbb{C}$
over $\mathbb{F}_q$ is defined as follows. Using such a code $\mathbb{C}$, a
file $\cal{F}$ consisting of $\alpha k$ symbols over $\mathbb{F}_q$ can be
distributed among $n$ nodes, each storing $\alpha$ symbols, in such a way that:
The file $\cal{F}$ can be recovered by downloading the content of any $k$ of
the $n$ nodes; and the content of any failed node can be reconstructed by
accessing any $d$ of the remaining $n-1$ nodes and downloading $\alpha/(d-k+1)$
symbols from each of these nodes. Unfortunately, explicit constructions of
$[n,k,d]$ MSR codes are known only for certain special cases: either low rate,
namely $k/n<0.5$, or high repair connectivity, namely $d = n-1$. Although
setting $d = n-1$ minimizes the repair bandwidth, it may be impractical to
connect to all the remaining nodes in order to repair a single failed node. Our
main result in this paper is an explicit construction of systematic-repair
$[n,k,d]$ MSR codes for all possible values of parameters $n,k,d$. In
particular, we construct systematic-repair MSR codes of high rate $k/n>0.5$ and
low repair connectivity $k< d<n-1$. Such codes were not previously known to
exist. In order to construct these codes, we solve simultaneously several
repair scenarios, each of which is expressible as an interference alignment
problem. Extension of our results beyond systematic repair remains an open
problem.


title: A converse to Fortin's Lemma in Banach spaces

abstract: The converse of Fortin's Lemma in Banach spaces is established in this Note.


title: Extending Consequence-Based Reasoning to SRIQ

abstract:
  Consequence-based calculi are a family of reasoning algorithms for
description logics (DLs), and they combine hypertableau and resolution in a way
that often achieves excellent performance in practice. Up to now, however, they
were proposed for either Horn DLs (which do not support disjunction), or for
DLs without counting quantifiers. In this paper we present a novel
consequence-based calculus for SRIQ---a rich DL that supports both features.
This extension is non-trivial since the intermediate consequences that need to
be derived during reasoning cannot be captured using DLs themselves. The
results of our preliminary performance evaluation suggest the feasibility of
our approach in practice.


title: Heat content estimates over sets of finite perimeter

abstract:
  This paper studies by means of standard analytic tools the small time
behavior of the heat content over a bounded Lebesgue measurable set of finite
perimeter by working with the set covariance function and by imposing
conditions on the heat kernels. Applications concerning the heat kernels of
rotational invariant $\alpha$-stable processes are given.


title:
Joint Pushing and Caching with a Finite Receiver Buffer: Optimal
  Policies and Throughput Analysis

abstract:
  Pushing and caching hold the promise of significantly increasing the
throughput of content-centric wireless networks. However, the throughput gain
of these techniques is limited by the buffer size of the receiver. To overcome
this, this paper presents a Joint Pushing and Caching (JPC) method that jointly
determines the contents to be pushed to, and to be removed from, the receiver
buffer in each timeslot. An offline and two online JPC policies are proposed
respectively based on noncausal, statistical, and causal content Request Delay
Information (RDI), which predicts a user's request time for certain content. It
is shown that the effective throughput of JPC is increased with the receiver
buffer size and the pushing channel capacity. Furthermore, the causal feedback
of user requests is found to greatly enhance the performance of online JPC
without inducing much signalling overhead in practice.


title:
Avoiding unrealistic priors: the case of dark energy constraints from
  the time variation of the fine-structure constant

abstract:
  We critically assess recent claims suggesting that upper limits on the time
variation of the fine-structure constant tightly constrain the coupling of a
dark energy scalar field to the electromagnetic sector, and, indirectly, the
violation of the weak equivalence principle. We show that such constraints
depend crucially on the assumed priors, even if the dark energy was described
by a dynamical scalar field with a constant equation of state parameter $w$
linearly coupled to the electromagnetic sector through a dimensionless coupling
$\zeta$. We find that, although local atomic clock tests, as well as other
terrestrial, astrophysical and cosmological data, put stringent bounds on
$|\zeta| {\sqrt {|w+1|}}$, the time variation of the fine-structure constant
cannot be used to set or to improve upper limits on $|\zeta|$ or $|w+1|$
without specifying priors, consistent but not favoured by current data, which
strongly disfavour low values of $|w+1|$ or $|\zeta|$, respectively. We briefly
discuss how this might change with a new generation of high-resolution
ultra-stable spectrographs, such as ESPRESSO and ELT-HIRES, in combination with
forthcoming missions to map the geometry of the Universe, such as Euclid, or to
test the equivalence principle, such as MICROSCOPE or STEP.


title: Do We Need Binary Features for 3D Reconstruction?

abstract:
  Binary features have been incrementally popular in the past few years due to
their low memory footprints and the efficient computation of Hamming distance
between binary descriptors. They have been shown with promising results on some
real time applications, e.g., SLAM, where the matching operations are relative
few. However, in computer vision, there are many applications such as 3D
reconstruction requiring lots of matching operations between local features.
Therefore, a natural question is that is the binary feature still a promising
solution to this kind of applications? To get the answer, this paper conducts a
comparative study of binary features and their matching methods on the context
of 3D reconstruction in a recently proposed large scale mutliview stereo
dataset. Our evaluations reveal that not all binary features are capable of
this task. Most of them are inferior to the classical SIFT based method in
terms of reconstruction accuracy and completeness with a not significant better
computational performance.