title: Strong swirl approximation and intensive vortices in the atmosphere

abstract:
  This work investigates intensive vortices, which are characterised by the
existence of a converging radial flow that significantly intensifies the flow
rotation. Evolution and amplification of the vorticity present in the flow play
important roles in the formation of the vortex. When rotation in the flow
becomes sufficiently strong - and this implies validity of the strong swirl
approximation developed by Einstein and Li (1951), Lewellen (1962), Turner
(1966) and Lundgren (1985) - the analysis of Klimenko (2001a-c) and of the
present work determine that further amplification of vorticity is moderated by
interactions of vorticity and velocity. This imposes physical constraints on
the flow resulting in the so-called compensating regime, where the radial
distribution of the axial vorticity is characterised by the 4/3 and 3/2 power
laws. This asymptotic treatment of a strong swirl is based on vorticity
equations and involves higher order terms. This treatment incorporates
multiscale analysis indicating downstream relaxation of the flow to the
compensating regime. The present work also investigates and takes into account
viscous and transient effects. One of the main points of this work is the
applicability of the power laws of the compensating regime to intermediate
regions in large atmospheric vortices, such as tropical cyclones and tornadoes.


title:
A Simple and Scalable Static Analysis for Bound Analysis and Amortized
  Complexity Analysis

abstract:
  We present the first scalable bound analysis that achieves amortized
complexity analysis. In contrast to earlier work, our bound analysis is not
based on general purpose reasoners such as abstract interpreters, software
model checkers or computer algebra tools. Rather, we derive bounds directly
from abstract program models, which we obtain from programs by comparatively
simple invariant generation and symbolic execution techniques. As a result, we
obtain an analysis that is more predictable and more scalable than earlier
approaches. Our experiments demonstrate that our analysis is fast and at the
same time able to compute bounds for challenging loops in a large real-world
benchmark. Technically, our approach is based on lossy vector addition systems
(VASS). Our bound analysis first computes a lexicographic ranking function that
proves the termination of a VASS, and then derives a bound from this ranking
function. Our methodology achieves amortized analysis based on a new insight
how lexicographic ranking functions can be used for bound analysis.


title: Disentangling Theorem and Monogamy for Entanglement Negativity

abstract:
  Entanglement negativity is a measure of mixed-state entanglement increasingly
used to investigate and characterize emerging quantum many-body phenomena,
including quantum criticality and topological order. We present two results for
the entanglement negativity: a disentangling theorem, which allows the use of
this entanglement measure as a means to detect whether a wave-function of three
subsystems $A$, $B$, and $C$ factorizes into a product state for parts $AB_1$
and $B_2C$; and a monogamy relation, which states that if $A$ is very entangled
with $B$, then $A$ cannot be simultaneaously very entangled also with $C$.


title:
Pulse-shape discrimination of surface events in CdZnTe detectors for the
  COBRA experiment

abstract:
  Events near the cathode and anode surfaces of a coplanar grid CdZnTe detector
are identifiable by means of the interaction depth information encoded in the
signal amplitudes. However, the amplitudes cannot be used to identify events
near the lateral surfaces. In this paper a method is described to identify
lateral surface events by means of their pulse shapes. Such identification
allows for discrimination of surface alpha particle interactions from more
penetrating forms of radiation, which is particularly important for rare event
searches. The effectiveness of the presented technique in suppressing
backgrounds due to alpha contamination in the search for neutrinoless double
beta decay with the COBRA experiment is demonstrated.


title:
Medium Effects on Charmonium Production at ultrarelativistic energies
  available at the CERN Large Haron Collider

abstract:
  We investigate with a transport approach the cold and hot nuclear matter
effects on the charmonium transverse momentum distributions in relativistic
heavy ion collisions. The newly defined nuclear modification factor
$r_{AA}=\langle p_{T}^2\rangle_{AA}/\langle p_{T}^2\rangle_{pp}$ and elliptic
flow $v_2$ for $J/\psi$ are sensitive to the nature of the hot medium and the
thermalization of heavy quarks. From SPS through RHIC to LHC colliding
energies, we observe dramatic changes in the centrality dependence of $r_{AA}$.
We find that at LHC energy, the finally observed charmonia are dominated by the
regeneration from thermalized heavy quarks.


title: Modal Logics with Hard Diamond-free Fragments

abstract:
  We investigate the complexity of modal satisfiability for certain
combinations of modal logics. In particular we examine four examples of
multimodal logics with dependencies and demonstrate that even if we restrict
our inputs to diamond-free formulas (in negation normal form), these logics
still have a high complexity. This result illustrates that having D as one or
more of the combined logics, as well as the interdependencies among logics can
be important sources of complexity even in the absence of diamonds and even
when at the same time in our formulas we allow only one propositional variable.
We then further investigate and characterize the complexity of the
diamond-free, 1-variable fragments of multimodal logics in a general setting.


title: Cotton tensor and conformal deformations of three-dimensional Ricci flow

abstract:
  We study the deformation of the three-dimensional conformal structures by the
Ricci flow. We drive the evolution equation of Cotton-York tensor and the
L1-norm of it under the Ricci flow. In particular, we investigate the behavior
of the L1-norm of the Cotton-York tensor under the Ricci flow on
three-dimensional simply-connected homogeneous manifolds which admit compact
quotients. For a non-homogeneous case, we also investigate the behavior of the
L1-norm of the Cotton-York tensor for the product metric of the Rosenau
solution for the Ricci flow on a two-sphere and the standard metric of a
circle.


title: Algorithms and Limits for Compact Plan Representations

abstract:
  Compact representations of objects is a common concept in computer science.
Automated planning can be viewed as a case of this concept: a planning instance
is a compact implicit representation of a graph and the problem is to find a
path (a plan) in this graph. While the graphs themselves are represented
compactly as planning instances, the paths are usually represented explicitly
as sequences of actions. Some cases are known where the plans always have
compact representations, for example, using macros. We show that these results
do not extend to the general case, by proving a number of bounds for compact
representations of plans under various criteria, like efficient sequential or
random access of actions. In addition to this, we show that our results have
consequences for what can be gained from reformulating planning into some other
problem. As a contrast to this we also prove a number of positive results,
demonstrating restricted cases where plans do have useful compact
representations, as well as proving that macro plans have favourable access
properties. Our results are finally discussed in relation to other relevant
contexts.


title:
Interactions between Knowledge and Time in a First-Order Logic for
  Multi-Agent Systems: Completeness Results

abstract:
  We investigate a class of first-order temporal-epistemic logics for reasoning
about multi-agent systems. We encode typical properties of systems including
perfect recall, synchronicity, no learning, and having a unique initial state
in terms of variants of quantified interpreted systems, a first-order extension
of interpreted systems. We identify several monodic fragments of first-order
temporal-epistemic logic and show their completeness with respect to their
corresponding classes of quantified interpreted systems.


title: The Logical Difference for the Lightweight Description Logic EL

abstract:
  We study a logic-based approach to versioning of ontologies. Under this view,
ontologies provide answers to queries about some vocabulary of interest. The
difference between two versions of an ontology is given by the set of queries
that receive different answers. We investigate this approach for terminologies
given in the description logic EL extended with role inclusions and domain and
range restrictions for three distinct types of queries: subsumption, instance,
and conjunctive queries. In all three cases, we present polynomial-time
algorithms that decide whether two terminologies give the same answers to
queries over a given vocabulary and compute a succinct representation of the
difference if it is non- empty. We present an implementation, CEX2, of the
developed algorithms for subsumption and instance queries and apply it to
distinct versions of Snomed CT and the NCI ontology.


title:
A Market-Inspired Approach for Intersection Management in Urban Road
  Traffic Networks

abstract:
  Traffic congestion in urban road networks is a costly problem that affects
all major cities in developed countries. To tackle this problem, it is possible
(i) to act on the supply side, increasing the number of roads or lanes in a
network, (ii) to reduce the demand, restricting the access to urban areas at
specific hours or to specific vehicles, or (iii) to improve the efficiency of
the existing network, by means of a widespread use of so-called Intelligent
Transportation Systems (ITS). In line with the recent advances in smart
transportation management infrastructures, ITS has turned out to be a promising
field of application for artificial intelligence techniques. In particular,
multiagent systems seem to be the ideal candidates for the design and
implementation of ITS. In fact, drivers can be naturally modelled as autonomous
agents that interact with the transportation management infrastructure, thereby
generating a large-scale, open, agent-based system. To regulate such a system
and maintain a smooth and efficient flow of traffic, decentralised mechanisms
for the management of the transportation infrastructure are needed.
  In this article we propose a distributed, market-inspired, mechanism for the
management of a future urban road network, where intelligent autonomous
vehicles, operated by software agents on behalf of their human owners, interact
with the infrastructure in order to travel safely and efficiently through the
road network. Building on the reservation-based intersection control model
proposed by Dresner and Stone, we consider two different scenarios: one with a
single intersection and one with a network of intersections. In the former, we
analyse the performance of a novel policy based on combinatorial auctions for
the allocation of reservations. In the latter, we analyse the impact that a
traffic assignment strategy inspired by competitive markets has on the drivers
route choices. Finally we propose an adaptive management mechanism that
integrates the auction-based traffic control policy with the competitive
traffic assignment strategy.


title:
Algorithms for Generating Ordered Solutions for Explicit AND/OR
  Structures

abstract:
  We present algorithms for generating alternative solutions for explicit
acyclic AND/OR structures in non-decreasing order of cost. The proposed
algorithms use a best first search technique and report the solutions using an
implicit representation ordered by cost. In this paper, we present two versions
of the search algorithm -- (a) an initial version of the best first search
algorithm, ASG, which may present one solution more than once while generating
the ordered solutions, and (b) another version, LASG, which avoids the
construction of the duplicate solutions. The actual solutions can be
reconstructed quickly from the implicit compact representation used. We have
applied the methods on a few test domains, some of them are synthetic while the
others are based on well known problems including the search space of the 5-peg
Tower of Hanoi problem, the matrix-chain multiplication problem and the problem
of finding secondary structure of RNA. Experimental results show the efficacy
of the proposed algorithms over the existing approach. Our proposed algorithms
have potential use in various domains ranging from knowledge based frameworks
to service composition, where the AND/OR structure is widely used for
representing problems.


title:
Reasoning over Ontologies with Hidden Content: The Import-by-Query
  Approach

abstract:
  There is currently a growing interest in techniques for hiding parts of the
signature of an ontology Kh that is being reused by another ontology Kv.
Towards this goal, in this paper we propose the import-by-query framework,
which makes the content of Kh accessible through a limited query interface. If
Kv reuses the symbols from Kh in a certain restricted way, one can reason over
Kv U Kh by accessing only Kv and the query interface. We map out the landscape
of the import-by-query problem. In particular, we outline the limitations of
our framework and prove that certain restrictions on the expressivity of Kh and
the way in which Kv reuses symbols from Kh are strictly necessary to enable
reasoning in our setting. We also identify cases in which reasoning is possible
and we present suitable import-by-query reasoning algorithms.


title: Avoiding and Escaping Depressions in Real-Time Heuristic Search

abstract:
  Heuristics used for solving hard real-time search problems have regions with
depressions. Such regions are bounded areas of the search space in which the
heuristic function is inaccurate compared to the actual cost to reach a
solution. Early real-time search algorithms, like LRTA*, easily become trapped
in those regions since the heuristic values of their states may need to be
updated multiple times, which results in costly solutions. State-of-the-art
real-time search algorithms, like LSS-LRTA* or LRTA*(k), improve LRTA*s
mechanism to update the heuristic, resulting in improved performance. Those
algorithms, however, do not guide search towards avoiding depressed regions.
This paper presents depression avoidance, a simple real-time search principle
to guide search towards avoiding states that have been marked as part of a
heuristic depression. We propose two ways in which depression avoidance can be
implemented: mark-and-avoid and move-to-border. We implement these strategies
on top of LSS-LRTA* and RTAA*, producing 4 new real-time heuristic search
algorithms: aLSS-LRTA*, daLSS-LRTA*, aRTAA*, and daRTAA*. When the objective is
to find a single solution by running the real-time search algorithm once, we
show that daLSS-LRTA* and daRTAA* outperform their predecessors sometimes by
one order of magnitude. Of the four new algorithms, daRTAA* produces the best
solutions given a fixed deadline on the average time allowed per planning
episode. We prove all our algorithms have good theoretical properties: in
finite search spaces, they find a solution if one exists, and converge to an
optimal after a number of trials.


title: Tractable Triangles and Cross-Free Convexity in Discrete Optimisation

abstract:
  The minimisation problem of a sum of unary and pairwise functions of discrete
variables is a general NP-hard problem with wide applications such as computing
MAP configurations in Markov Random Fields (MRF), minimising Gibbs energy, or
solving binary Valued Constraint Satisfaction Problems (VCSPs).
  We study the computational complexity of classes of discrete optimisation
problems given by allowing only certain types of costs in every triangle of
variable-value assignments to three distinct variables. We show that for
several computational problems, the only non- trivial tractable classes are the
well known maximum matching problem and the recently discovered joint-winner
property. Our results, apart from giving complete classifications in the
studied cases, provide guidance in the search for hybrid tractable classes;
that is, classes of problems that are not captured by restrictions on the
functions (such as submodularity) or the structure of the problem graph (such
as bounded treewidth).
  Furthermore, we introduce a class of problems with convex cardinality
functions on cross-free sets of assignments. We prove that while imposing only
one of the two conditions renders the problem NP-hard, the conjunction of the
two gives rise to a novel tractable class satisfying the cross-free convexity
property, which generalises the joint-winner property to problems of unbounded
arity.


title: Narrative Planning: Compilations to Classical Planning

abstract:
  A model of story generation recently proposed by Riedl and Young casts it as
planning, with the additional condition that story characters behave
intentionally. This means that characters have perceivable motivation for the
actions they take. I show that this condition can be compiled away (in more
ways than one) to produce a classical planning problem that can be solved by an
off-the-shelf classical planner, more efficiently than by Riedl and Youngs
specialised planner.


title: COLIN: Planning with Continuous Linear Numeric Change

abstract:
  In this paper we describe COLIN, a forward-chaining heuristic search planner,
capable of reasoning with COntinuous LINear numeric change, in addition to the
full temporal semantics of PDDL. Through this work we make two advances to the
state-of-the-art in terms of expressive reasoning capabilities of planners: the
handling of continuous linear change, and the handling of duration-dependent
effects in combination with duration inequalities, both of which require
tightly coupled temporal and numeric reasoning during planning. COLIN combines
FF-style forward chaining search, with the use of a Linear Program (LP) to
check the consistency of the interacting temporal and numeric constraints at
each state. The LP is used to compute bounds on the values of variables in each
state, reducing the range of actions that need to be considered for
application. In addition, we develop an extension of the Temporal Relaxed
Planning Graph heuristic of CRIKEY3, to support reasoning directly with
continuous change. We extend the range of task variables considered to be
suitable candidates for specifying the gradient of the continuous numeric
change effected by an action. Finally, we explore the potential for employing
mixed integer programming as a tool for optimising the timestamps of the
actions in the plan, once a solution has been found. To support this, we
further contribute a selection of extended benchmark domains that include
continuous numeric effects. We present results for COLIN that demonstrate its
scalability on a range of benchmarks, and compare to existing state-of-the-art
planners.


title:
SAP Speaks PDDL: Exploiting a Software-Engineering Model for Planning in
  Business Process Management

abstract:
  Planning is concerned with the automated solution of action sequencing
problems described in declarative languages giving the action preconditions and
effects. One important application area for such technology is the creation of
new processes in Business Process Management (BPM), which is essential in an
ever more dynamic business environment. A major obstacle for the application of
Planning in this area lies in the modeling. Obtaining a suitable model to plan
with -- ideally a description in PDDL, the most commonly used planning language
-- is often prohibitively complicated and/or costly. Our core observation in
this work is that this problem can be ameliorated by leveraging synergies with
model-based software development. Our application at SAP, one of the leading
vendors of enterprise software, demonstrates that even one-to-one model re-use
is possible.
  The model in question is called Status and Action Management (SAM). It
describes the behavior of Business Objects (BO), i.e., large-scale data
structures, at a level of abstraction corresponding to the language of business
experts. SAM covers more than 400 kinds of BOs, each of which is described in
terms of a set of status variables and how their values are required for, and
affected by, processing steps (actions) that are atomic from a business
perspective. SAM was developed by SAP as part of a major model-based software
engineering effort. We show herein that one can use this same model for
planning, thus obtaining a BPM planning application that incurs no modeling
overhead at all.
  We compile SAM into a variant of PDDL, and adapt an off-the-shelf planner to
solve this kind of problem. Thanks to the resulting technology, business
experts may create new processes simply by specifying the desired behavior in
terms of status variable value changes: effectively, by describing the process
in their own language.


title: Plan-based Policies for Efficient Multiple Battery Load Management

abstract:
  Efficient use of multiple batteries is a practical problem with wide and
growing application. The problem can be cast as a planning problem under
uncertainty. We describe the approach we have adopted to modelling and solving
this problem, seen as a Markov Decision Problem, building effective policies
for battery switching in the face of stochastic load profiles.
  Our solution exploits and adapts several existing techniques: planning for
deterministic mixed discrete-continuous problems and Monte Carlo sampling for
policy learning. The paper describes the development of planning techniques to
allow solution of the non-linear continuous dynamic models capturing the
battery behaviours. This approach depends on carefully handled discretisation
of the temporal dimension. The construction of policies is performed using a
classification approach and this idea offers opportunities for wider
exploitation in other problems. The approach and its generality are described
in the paper.
  Application of the approach leads to construction of policies that, in
simulation, significantly outperform those that are currently in use and the
best published solutions to the battery management problem. We achieve
solutions that achieve more than 99% efficiency in simulation compared with the
theoretical limit and do so with far fewer battery switches than existing
policies. Behaviour of physical batteries does not exactly match the simulated
models for many reasons, so to confirm that our theoretical results can lead to
real measured improvements in performance we also conduct and report
experiments using a physical test system. These results demonstrate that we can
obtain 5%-15% improvement in lifetimes in the case of a two battery system.


title: A New Look at BDDs for Pseudo-Boolean Constraints

abstract:
  Pseudo-Boolean constraints are omnipresent in practical applications, and
thus a significant effort has been devoted to the development of good SAT
encoding techniques for them. Some of these encodings first construct a Binary
Decision Diagram (BDD) for the constraint, and then encode the BDD into a
propositional formula. These BDD-based approaches have some important
advantages, such as not being dependent on the size of the coefficients, or
being able to share the same BDD for representing many constraints.
  We first focus on the size of the resulting BDDs, which was considered to be
an open problem in our research community. We report on previous work where it
was proved that there are Pseudo-Boolean constraints for which no polynomial
BDD exists. We also give an alternative and simpler proof assuming that NP is
different from Co-NP. More interestingly, here we also show how to overcome the
possible exponential blowup of BDDs by phcoefficient decomposition. This allows
us to give the first polynomial generalized arc-consistent ROBDD-based encoding
for Pseudo-Boolean constraints.
  Finally, we focus on practical issues: we show how to efficiently construct
such ROBDDs, how to encode them into SAT with only 2 clauses per node, and
present experimental results that confirm that our approach is competitive with
other encodings and state-of-the-art Pseudo-Boolean solvers.


title: Online Speedup Learning for Optimal Planning

abstract:
  Domain-independent planning is one of the foundational areas in the field of
Artificial Intelligence. A description of a planning task consists of an
initial world state, a goal, and a set of actions for modifying the world
state. The objective is to find a sequence of actions, that is, a plan, that
transforms the initial world state into a goal state. In optimal planning, we
are interested in finding not just a plan, but one of the cheapest plans. A
prominent approach to optimal planning these days is heuristic state-space
search, guided by admissible heuristic functions. Numerous admissible
heuristics have been developed, each with its own strengths and weaknesses, and
it is well known that there is no single "best heuristic for optimal planning
in general. Thus, which heuristic to choose for a given planning task is a
difficult question. This difficulty can be avoided by combining several
heuristics, but that requires computing numerous heuristic estimates at each
state, and the tradeoff between the time spent doing so and the time saved by
the combined advantages of the different heuristics might be high. We present a
novel method that reduces the cost of combining admissible heuristics for
optimal planning, while maintaining its benefits. Using an idealized search
space model, we formulate a decision rule for choosing the best heuristic to
compute at each state. We then present an active online learning approach for
learning a classifier with that decision rule as the target concept, and employ
the learned classifier to decide which heuristic to compute at each state. We
evaluate this technique empirically, and show that it substantially outperforms
the standard method for combining several heuristics via their pointwise
maximum.


title:
Magnetic form factors of the octet baryons from lattice QCD and chiral
  extrapolation

abstract:
  We present a 2+1--flavor lattice QCD calculation of the electromagnetic Dirac
and Pauli form factors of the octet baryons. The magnetic Sachs form factor is
extrapolated at six fixed values of $Q^2$ to the physical pseudoscalar masses
and infinite volume using a formulation based on heavy baryon chiral
perturbation theory with finite-range regularization. We properly account for
omitted disconnected quark contractions using a partially-quenched effective
field theory formalism. The results compare well with the experimental form
factors of the nucleon and the magnetic moments of the octet baryons.


title: Complexity of Judgment Aggregation

abstract:
  We analyse the computational complexity of three problems in judgment
aggregation: (1) computing a collective judgment from a profile of individual
judgments (the winner determination problem); (2) deciding whether a given
agent can influence the outcome of a judgment aggregation procedure in her
favour by reporting insincere judgments (the strategic manipulation problem);
and (3) deciding whether a given judgment aggregation scenario is guaranteed to
result in a logically consistent outcome, independently from what the judgments
supplied by the individuals are (the problem of the safety of the agenda). We
provide results both for specific aggregation procedures (the quota rules, the
premise-based procedure, and a distance-based procedure) and for classes of
aggregation procedures characterised in terms of fundamental axioms.


title:
The high-redshift star formation rate derived from GRBs: possible origin
  and cosmic reionization

abstract:
  The collapsar model of long gamma-ray bursts (GRBs) indicates that they may
trace the star formation history. So long GRBs may be a useful tool of
measuring the high-redshift star formation rate (SFR). The collapsar model
explains GRB formation via the collapse of a rapidly rotating massive star with
$M> 30M_\odot$ into a black hole, which may imply a decrease of SFR at high
redshift. However, we find that the \emph{Swift} GRBs during 2005-2012 are
biased tracing the SFR, including a factor about $(1+z)^{0.5}$, which is in
agreement with recent results. After taking this factor, the SFR derived from
GRBs does not show steep drop up to $z\sim 9.4$. We consider the GRBs produced
by rapidly rotating metal-poor stars with low masses to explain the
high-redshift GRB rate excess. The chemically homogeneous evolution scenario
(CHES) of rapidly rotating stars with mass larger than $12M_\odot$ is
recognized as a promising path towards collapsars in connection with long GRBs.
Our results indicate that the stars in the mass range $12M_\odot<M<30M_\odot$
for low enough metallicity $Z\leq 0.004$ with the GRB efficiency factor
$10^{-5}$ can fit the derived SFR with good accuracy. Combining these two
factors, we find that the conversion efficiency from massive stars to GRBs is
enhanced by a factor of 10, which may be able to explain the excess of the
high-redshift GRB rate. We also investigate the cosmic reionization history
using the derived SFR. The GRB-inferred SFR would be sufficient to maintain
cosmic reionization over $6<z<10$ and reproduce the observed optical depth of
Thomson scattering to the cosmic microwave background.


title: Anisotropic Rabi model

abstract:
  We define the anisotropic Rabi model as the generalization of the spin-boson
Rabi model: The Hamiltonian system breaks the parity symmetry; the rotating and
counter-rotating interactions are governed by two different coupling constants;
a further parameter introduces a phase factor in the counter-rotating terms.
The exact energy spectrum and eigenstates of the generalized model is worked
out. The solution is obtained as an elaboration of a recent proposed method for
the isotropic limit of the model. In this way, we provide a long sought
solution of a cascade of models with immediate relevance in different physical
fields, including i) quantum optics: two-level atom in single mode cross
electric and magnetic fields; ii) solid state physics: electrons in
semiconductors with Rashba and Dresselhaus spin-orbit coupling; iii) mesoscopic
physics: Josephson junctions flux-qubit quantum circuits.


title: Farey map, Diophantine approximation and Bruhat-Tits tree

abstract:
  Based on Broise-Alamichel and Paulin's work on the Gauss map corresponding to
the principal convergents, we continue the study of the Gauss map via Farey
maps to contain all the intermediate convergents. We define the geometric Farey
map, which is given by time-1 map of the geodesic flow. We also define
algebraic Farey maps, better suited for arithmetic properties, which produce
all the intermediate convergents. Then we obtain the ergodic invariant measures
for the Farey maps and the convergent speed.


title: Fukaya's conjecture on Witten's twisted $A_\infty$-structures

abstract:
  Wedge product on deRham complex of a Riemannian manifold $M$ can be pulled
back to $H^*(M)$ via explicit homotopy, constructed using Green's operator, to
give higher product structures. We prove Fukaya's conjecture which suggests
that Witten deformation of these higher product structures have semiclassical
limits as operators defined by counting gradient flow trees with respect to
Morse functions, which generalizes the remarkable Witten deformation of deRham
differential from a statement concerning homology to one concerning real
homotopy type of $M$. Various applications of this conjecture to mirror
symmetry are also suggested by Fukaya.


title: Level Matrices

abstract:
  Let $n>1$ and $k>0$ be fixed integers. A matrix is said to be level if all
its column sums are equal. A level matrix with $m$ rows is called reducible if
we can delete $j$ rows, $0<j<m$, so that the remaining matrix is level. We ask
if there is a minimum integer $\ell=\ell(n,k)$ such that for all $m>\ell$, any
$m\times n$ level matrix with entries in $\{0,\ldots,k\}$ is reducible. It is
known that $\ell(2,k)=2k-1$. In this paper, we establish the existence of
$\ell(n,k)$ for $n\geq 3$ by giving upper and lower bounds for it. We then
apply this result to bound the number of certain types of vector space
multipartitions.


title: An Enhanced Branch-and-bound Algorithm for the Talent Scheduling Problem

abstract:
  The talent scheduling problem is a simplified version of the real-world film
shooting problem, which aims to determine a shooting sequence so as to minimize
the total cost of the actors involved. In this article, we first formulate the
problem as an integer linear programming model. Next, we devise a
branch-and-bound algorithm to solve the problem. The branch-and-bound algorithm
is enhanced by several accelerating techniques, including preprocessing,
dominance rules and caching search states. Extensive experiments over two sets
of benchmark instances suggest that our algorithm is superior to the current
best exact algorithm. Finally, the impacts of different parameter settings are
disclosed by some additional experiments.


title:
X-ray Emission from Eta Carinae near Periastron in 2009 I: A Two State
  Solution

abstract:
  X-ray emission from the supermassive binary system Eta Carinae declines
sharply around periastron. This X-ray minimum has two distinct phases - the
lowest flux phase in the first ~3 weeks and a brighter phase thereafter. In
2009, the Chandra X-ray Observatory monitored the first phase five times and
found the lowest observed flux at ~1.9e-12 ergs cm-2 s-1 (3-8 keV). The
spectral shape changed such that the hard band above ~4 keV dropped quickly at
the beginning and the soft band flux gradually decreased to its lowest observed
value in ~2 weeks. The hard band spectrum had begun to recover by that time.
This spectral variation suggests that the shocked gas producing the hottest
X-ray gas near the apex of the wind-wind collision (WWC) is blocked behind the
dense inner wind of the primary star, which later occults slightly cooler gas
downstream. Shocked gas previously produced by the system at earlier orbital
phases is suggested to produce the faint residual X-ray emission seen when the
emission near the apex is completely blocked by the primary wind. The brighter
phase is probably caused by the re-appearance of the WWC plasma, whose
emissivity significantly declined during the occultation. We interpret this to
mean that the X-ray minimum is produced by a hybrid mechanism of an occultation
and a decline in emissivity of the WWC shock.


title: Serefind: A Social Networking Website for Classifieds

abstract:
  This paper presents the design and implementation of a social networking
website for classifieds, called Serefind. We designed search interfaces with
focus on security, privacy, usability, design, ranking, and communications. We
deployed this site at the Johns Hopkins University, and the results show it can
be used as a self-sustaining classifieds site for public or private
communities.


title: Software Pauli Tracking for Quantum Computation

abstract:
  The realisation of large-scale quantum computing is no longer simply a
hardware question. The rapid development of quantum technology has resulted in
dozens of control and programming problems that should be directed towards the
classical computer science and engineering community. One such problem is known
as Pauli tracking. Methods for implementing quantum algorithms that are
compatible with crucial error correction technology utilise extensive quantum
teleportation protocols. These protocols are intrinsically probabilistic and
result in correction operators that occur as byproducts of teleportation. These
byproduct operators do not need to be corrected in the quantum hardware itself.
Instead, byproduct operators are tracked through the circuit and output results
reinterpreted. This tracking is routinely ignored in quantum information as it
is assumed that tracking algorithms will eventually be developed. In this work
we help fill this gap and present an algorithm for tracking byproduct operators
through a quantum computation. We formulate this work based on quantum gate
sets that are compatible with all major forms of quantum error correction and
demonstrate the completeness of the algorithm.


title:
Nonlinear Photoluminescence Properties of Trions in Hole-doped
  Single-walled Carbon Nanotubes

abstract:
  We studied the excitation density dependence of photoluminescence (PL)
spectra of excitons and trions (charged excitons) in hole-doped single-walled
carbon nanotubes. We found that the PL intensity of trions exhibited a strong
nonlinear saturation behavior as the excitation density increased, whereas that
of excitons exhibited a weak sublinear behavior. The strong PL saturation of
trions is attributed to depletion of doped holes that are captured by excitons
in the formation processes. Moreover, the effective radiative lifetime of a
trion was evaluated to be approximately 20 ns.


title:
Distribution properties of compressing sequences derived from primitive
  sequences modulo odd prime powers

abstract:
  Let $\underline{a}$ and $\underline{b}$ be primitive sequences over
$\mathbb{Z}/(p^e)$ with odd prime $p$ and $e\ge 2$. For certain compressing
maps, we consider the distribution properties of compressing sequences of
$\underline{a}$ and $\underline{b}$, and prove that
$\underline{a}=\underline{b}$ if the compressing sequences are equal at the
times $t$ such that $\alpha(t)=k$, where $\underline{\alpha}$ is a sequence
related to $\underline{a}$. We also discuss the $s$-uniform distribution
property of compressing sequences. For some compressing maps, we have that
there exist different primitive sequences such that the compressing sequences
are $s$-uniform. We also discuss that compressing sequences can be $s$-uniform
for how many elements $s$.


title:
The mean number of 3-torsion elements in the class groups and ideal
  groups of quadratic orders

abstract:
  We determine the mean number of 3-torsion elements in the class groups of
quadratic orders, where the quadratic orders are ordered by their absolute
discriminants. Moreover, for a quadratic order $\mathcal{O}$ we distinguish
between the two groups: $\mathrm{Cl}_3(\mathcal{O})$, the group of ideal
classes of order $3$; and $\mathcal{I}_3(\mathcal{O})$, the group of ideals of
order $3$. We determine the mean values of both $|\mathrm{Cl}_3(\mathcal{O})|$
and $|\mathcal{I}_3(\mathcal{O})|$, as $\mathcal{O}$ ranges over any family of
orders defined by finitely many (or in suitable cases, even infinitely many)
local conditions.
  As a consequence, we prove the surprising fact that the mean value of the
difference $|\mathrm{Cl}_3(\mathcal{O})|-|\mathcal{I}_3(\mathcal{O})|$ is equal
to $1$, regardless of whether one averages over the maximal orders in complex
quadratic fields or over all orders in such fields or, indeed, over any family
of complex quadratic orders defined by local conditions. For any family of real
quadratic orders defined by local conditions, we prove similarly that the mean
value of the difference
$|\mathrm{Cl}_3(\mathcal{O})|-\frac13|\mathcal{I}_3(\mathcal{O})|$ is always
equal to $1$, independent of the family.


title: Tidal evolution of the spin-orbit angle in exoplanetary systems

abstract:
  The angle between the stellar spin and the planetary orbit axes (spin-orbit
angle) is supposed to carry valuable information on the initial condition of
the planet formation and the subsequent migration history. Indeed current
observations of the Rossiter- McLaughlin effect have revealed a wide range of
spin-orbit misalignments for transiting exoplanets. We examine in detail the
tidal evolution of a simple system comprising a Sun-like star and a hot Jupiter
adopting the equilibrium tide and the inertial wave dissipation effects
simultaneously. We find that the combined tidal model works as a very efficient
realignment mechanism; it predicts three distinct states of the spin-orbit
angle (i.e., parallel, polar, and anti-parallel orbits) for a while, but the
latter two states eventually approach the parallel spin-orbit configuration.
The intermediate spin-orbit angles as measured in recent observations are
difficult to be achieved. Therefore the current model cannot reproduce the
observed broad distribution of the spin-orbit angles, at least in its simple
form. This indicates that the observed diversity of the spin-orbit angles may
emerge from more complicated interactions with outer planets and/or may be the
consequence of the primordial misalignment between the proto-planetary disk and
the stellar spin, which requires future detailed studies.


title:
General Neutrino Mass Matrix Patterns and Its Underlying Family
  Symmetries

abstract:
  Based on current experimental results, such as neutrino oscillations and the
neutrinoless double beta decays (i.e. data from Super Kamiokande, KamLAND, SNO,
etc.), the neutrino mixing matrix can be adequately determined. Though there
are still certain parameters that have possibility limits, but based on the
current experimental results it is possible to construct a general form of
neutrino mass matrix. Starting from this general form of the neutrino mass
matrix we put certain conditions in the context of the seesaw mechanism model
to determine the possible pattern of the neutrino mass matrix that has a
texture zero. From the obtained neutrino mass matrix pattern, there are three
class of patterns, where two of the class are known to be realized in
literature by the underlying family symmetries of the $D_{4}$ and $A_{4}$
groups, the dihedral and tetrahedral symmetry groups.


title:
State of the Practice in Software Effort Estimation: A Survey and
  Literature Review

abstract:
  Effort estimation is a key factor for software project success, defined as
delivering software of agreed quality and functionality within schedule and
budget. Traditionally, effort estimation has been used for planning and
tracking project resources. Effort estimation methods founded on those goals
typically focus on providing exact estimates and usually do not support
objectives that have recently become important within the software industry,
such as systematic and reliable analysis of causal effort dependencies. This
article presents the results of a study of software effort estimation from an
industrial perspective. The study surveys industrial objectives, the abilities
of software organizations to apply certain estimation methods, and actually
applied practices of software effort estimation. Finally, requirements for
effort estimation methods identified in the survey are compared against
existing estimation methods.


title:
All-diamond optical assemblies for a beam-multiplexing X-ray
  monochromator at the Linac Coherent Light Source

abstract:
  A double-crystal diamond (111) monochromator recently implemented at the
Linac Coherent Light Source (LCLS) enables splitting of the primary X-ray beam
into a pink (transmitted) and a monochromatic (reflected) branch. The first
monochromator crystal with a thickness of 100 um provides sufficient X-ray
transmittance to enable simultaneous operation of two beamlines. Here we report
on the design, fabrication, and X-ray characterization of the first and second
(300-um-thick) crystals utilized in the monochromator and the optical
assemblies holding these crystals. Each crystal plate has a region of about 5 X
2 mm2 with low defect concentration, sufficient for use in X-ray optics at the
LCLS. The optical assemblies holding the crystals were designed to provide
mounting on a rigid substrate and to minimize mounting-induced crystal strain.
The induced strain was evaluated using double-crystal X-ray topography and was
found to be small over the 5 X 2 mm2 working regions of the crystals.


title: Probing Hidden Sectors with St\"uckelberg U(1) Gauge Fields

abstract:
  We propose a framework in which visible matter interacts with matter from a
hidden sector through mass mixings of St\"uckelberg U(1) gauge fields. In
contrast to other Z' mediation scenarios, our setup has the added appealing
features that (i) the choice of Z's can be significantly broadened without
necessarily introducing unwanted exotic matter and (ii) there can be sizable
tree-level interactions between the visible and hidden sectors. String theory
embeddings of this scenario and their phenomenological features are briefly
discussed.


title:
A Mixed-Binary Convex Quadratic Reformulation for Box-Constrained
  Nonconvex Quadratic Integer Program

abstract:
  In this paper, we propose a mixed-binary convex quadratic programming
reformulation for the box-constrained nonconvex quadratic integer program and
then implement IBM ILOG CPLEX 12.6 to solve the new model. Computational
results demonstrate that our approach clearly outperform the very recent
state-of-the-art solvers.


title:
Transceiver design for single-cell and multi-cell downlink multiuser
  MIMO systems

abstract:
  This thesis designs linear transceivers for the down link multiple user
multiple input multiple output single-cell and multiple-cell systems. The
transceivers are designed by assuming perfect and imperfect channel state
information at the BS and mobile stations (MS). Different signal to
interference plus noise ratio, mean square error and rate-based design criteria
are considered. These design criteria are formulated by considering total BS,
per BS antenna, per user, per symbol or a combination of per BS antenna and per
user (symbol) power constraints. To solve these problems generalized down link
up link and down link interference duality approaches are proposed.
  We have also shown that the weighted sum rate maximization problem can be
equivalently formulated as weighted sum mean square error minimization problem
with additional optimization variables and constraints. We also develop
distributed transceiver design algorithms to solve weighted sum rate and mean
square error optimization problems for coordinated BS systems. The distributed
transceiver design algorithms employ modify matrix fractional minimization and
Lagrangian dual decomposition methods.


title:
Photon-assisted scattering and magnetoconductivity oscillations in a
  strongly correlated 2D electron system formed on the surface of liquid helium

abstract:
  The influence of strong internal forces on photon-assisted scattering and on
the displacement mechanism of magnetoconductivity oscillations in a
two-dimensional (2D) electron gas is theoretically studied. The theory is
applied to the highly correlated system of surface electrons on liquid helium
under conditions that the microwave frequency is substantially different from
inter-subband resonance frequencies. A strong dependence of the amplitude of
magnetoconductivity oscillations on the electron density is established. The
possibility of experimental observation of such oscillations caused by
photon-assisted scattering is discussed.


title:
Existence of a lower bound for the distance between point masses of
  relative equilibria in $\mathbb{S}^{k-1}$, $k\geq 3$

abstract:
  We prove that if for the curved $n$-body problem in $\mathbb{S}^{k-1}$,
$k\geq 3$, the masses are given, the minimum distance between the point masses
of a specific type of relative equilibrium solution that is a generalisation of
positive elliptic relative equilibria and positive elliptic-elliptic relative
equilibria has a universal lower bound that is not equal to zero.


title: Microlocal approach to Lusztig's symmetries

abstract:
  We reformulate the De Concini -- Toledano Laredo conjecture about the
monodromy of the Casimir connection in terms of a relation between Lusztig's
symmetries of quantum group modules and the monodromy in the vanishing cycles
of factorizable sheaves.


title: Novel Heavy Quark Phenomena in QCD

abstract:
  Heavy quarks provide a new dimension to QCD, allowing tests of fundamental
theory, the nature of color confinement, and the production of new exotic
multiquark states. I also discuss novel explanations for several apparently
anomalous experimental results, such as the large $t \bar t$ forward-backward
asymmetry observed in $p \bar p$ colisions at the Tevatron, the large rates for
$\gamma$ or $Z$ plus high-$p_T$ charm jets observed at the Tevatron, the strong
nuclear absorption of the $J/\psi$ observed in $pA$ collisions at the LHC, as
well as fixed target experiments at high $x_F$. Precision measurements of the
heavy quark distribution in hadrons at high $x$ are needed since intrinsic
heavy quarks can play an important role in high $x$ phenomenology as well as
predicting a new mechanism for high-$x_F$ Higgs production. The role of
multi-parton interactions, such as di-gluon initiated subprocesses for forward
quarkonium hadroproduction, is discussed. I also briefly discuss a new approach
to the QCD confinement potential and the origin of the QCD mass scale based on
AdS/QCD, light-front holography and a unique extension of conformal theory. The
renormalization scale ambiguity can be eliminated at finite orders in pQCD
using the scheme-independent PMC procedure, thus increasing the precision of
predictions and eliminating an unnecessary source of theoretical systematic
error.


title: Entanglement-assisted weak value amplification

abstract:
  Large weak values have been used to amplify the sensitivity of a linear
response signal for detecting changes in a small parameter, which has also
enabled a simple method for precise parameter estimation. However, producing a
large weak value requires a low postselection probability for an ancilla degree
of freedom, which limits the utility of the technique. We propose an
improvement to this method that uses entanglement to increase the efficiency.
We show that by entangling and postselecting $n$ ancillas, the postselection
probability can be increased by a factor of $n$ while keeping the weak value
fixed (compared to $n$ uncorrelated attempts with one ancilla), which is the
optimal scaling with $n$ that is expected from quantum metrology. Furthermore,
we show the surprising result that the quantum Fisher information about the
detected parameter can be almost entirely preserved in the postselected state,
which allows the sensitive estimation to approximately saturate the optimal
quantum Cram\'{e}r-Rao bound. To illustrate this protocol we provide simple
quantum circuits that can be implemented using current experimental
realizations of three entangled qubits.


title:
Efficiently Detecting Overlapping Communities through Seeding and
  Semi-Supervised Learning

abstract:
  Seeding then expanding is a commonly used scheme to discover overlapping
communities in a network. Most seeding methods are either too complex to scale
to large networks or too simple to select high-quality seeds, and the
non-principled functions used by most expanding methods lead to poor
performance when applied to diverse networks. This paper proposes a new method
that transforms a network into a corpus where each edge is treated as a
document, and all nodes of the network are treated as terms of the corpus. An
effective seeding method is also proposed that selects seeds as a training set,
then a principled expanding method based on semi-supervised learning is applied
to classify edges. We compare our new algorithm with four other community
detection algorithms on a wide range of synthetic and empirical networks.
Experimental results show that the new algorithm can significantly improve
clustering performance in most cases. Furthermore, the time complexity of the
new algorithm is linear to the number of edges, and this low complexity makes
the new algorithm scalable to large networks.


title:
Geospatial Analysis Requires a Different Way of Thinking: The Problem of
  Spatial Heterogeneity

abstract:
  Geospatial analysis is very much dominated by a Gaussian way of thinking,
which assumes that things in the world can be characterized by a well-defined
mean, i.e., things are more or less similar in size. However, this assumption
is not always valid. In fact, many things in the world lack a well-defined
mean, and therefore there are far more small things than large ones. This paper
attempts to argue that geospatial analysis requires a different way of thinking
- a Paretian way of thinking that underlies skewed distribution such as power
laws, Pareto and lognormal distributions. I review two properties of spatial
dependence and spatial heterogeneity, and point out that the notion of spatial
heterogeneity in current spatial statistics is only used to characterize local
variance of spatial dependence. I subsequently argue for a broad perspective on
spatial heterogeneity, and suggest it be formulated as a scaling law. I further
discuss the implications of Paretian thinking and the scaling law for better
understanding of geographic forms and processes, in particular while facing
massive amounts of social media data. In the spirit of Paretian thinking,
geospatial analysis should seek to simulate geographic events and phenomena
from the bottom up rather than correlations as guided by Gaussian thinking.


title: Building a St\"uckelberg Portal

abstract:
  We construct explicit string theory models realizing the recently proposed
"St\"uckelberg Portal" scenario, a framework for building Z' mediation models
without the need to introduce unwanted exotic matter charged under the Standard
Model. This scenario can be viewed purely field-theoretically, although it is
particularly well motivated from string theory. By analyzing carefully the
St\"uckelberg couplings between the Abelian gauge bosons and the RR axions, we
construct the first global intersecting brane models which extend the Standard
Model with a genuine hidden sector, to which it is nonetheless connected via
U(1) mass mixings. Utilizing the explicit models we construct, we discuss some
broad phenomenological properties and experimental implications of this
scenario such as Z-Z' mixings, dark matter stability and relic density, and
supersymmetry mediation. With an appropriate confining hidden sector, our setup
also provides a minimal realization of the hidden valley scenario. We further
explore the possibility of obtaining small Z' masses from a large ensemble of
U(1) bosons. Related to the St\"uckelberg portal are two mechanisms that
connect the visible and the hidden sectors, namely mediation by
non-perturbative operators and the hidden photon scenario, on which we briefly
comment.


title: Hierarchical pixel clustering for image segmentation

abstract:
  In the paper a piecewise constant image approximations of sequential number
of pixel clusters or segments are treated. A majorizing of optimal
approximation sequence by hierarchical sequence of image approximations is
studied. Transition from pixel clustering to image segmentation by reducing of
segment numbers in clusters is provided. Algorithms are proved by elementary
formulas.


title: The Perron-Frobenius Theorem for Markov Semigroups

abstract:
  Let $P^V_t$, $t\ge0$, be the Schrodinger semigroup associated to a potential
$V$ and Markov semigroup $P_t$, $t\ge0$, on $C(X)$. Existence is established of
a left eigenvector and right eigenvector corresponding to the spectral radius
$e^{\lambda_0t}$ of $P^V_t$, simultaneously for all $t\ge0$. This is derived
with no compactness assumption on the semigroup operators.


title:
Role of functionality in two-component signal transduction: A stochastic
  study

abstract:
  We present a stochastic formalism for signal transduction processes in
bacterial two-component system. Using elementary mass action kinetics, the
proposed model takes care of signal transduction in terms of phosphotransfer
mechanism between the cognate partners of a two-component system, viz, the
sensor kinase and the response regulator. Based on the difference in
functionality of the sensor kinase, the noisy phosphotransfer mechanism has
been studied for monofunctional and bifunctional two component system using the
formalism of linear noise approximation. Steady state analysis of both models
quantifies different physically realizable quantities, e.g., variance,
coefficient of variation, mutual information. The resultant data reveals that
both systems reliably transfer information of extra-cellular environment under
low external stimulus and at high kinase and phosphatase regime. We extend our
analysis further by studying the role of two-component system in downstream
gene regulation.


title: "Quantum machine" to solve quantum "measurement problem"?

abstract:
  Recently a study of the first superposed mechanical quantum object
("machine") visible to the naked eye was published. However, as we show, it
turns out that if the object would actually be observed, i.e. would interact
with an optical photon, the quantum behavior should vanish. This, the actual
observation, has long been suspected in many interpretations of quantum
mechanics to be what makes the transition quantum $\rightarrow$ classical, but
so far it has not been available for direct experimental study in a mechanical
system. We show how any interaction, even a purely quantum one, of sufficient
strength can constitute a physical "measurement" - essentially the emergence of
an effectively classical object - active observation thus being a sufficient
but not necessary criterion. So it seems we have in this case of the "quantum
machine" a unique possibility to study, and possibly solve, the long-standing
"measurement problem" of quantum mechanics.


title: Timed-Release Secret Sharing Scheme with Information Theoretic Security

abstract:
  In modern cryptography, the secret sharing scheme is an important
cryptographic primitive and it is used in various situations. In this paper, a
timed-release secret sharing scheme (TR-SS) with information-theoretic security
is first studied. TR-SS is a secret sharing scheme with the property that
participants more than a threshold number can reconstruct a secret by using
their shares only when the time specified by a dealer has come. Specifically,
in this paper we first introduce a model and formalization of security for
TR-SS based on the traditional secret sharing scheme and information-theoretic
timed-release security. We also derive tight lower bounds on the sizes of
shares, time-signals, and entities' secret-keys required for TR-SS. In
addition, we propose a direct construction for TR-SS. Our direct construction
is optimal in the sense that the construction meets equality in each of our
bounds. As a result, it is shown that the timed-release security can be
realized without any additional redundancy on the share-size.


title: Secret Sharing Schemes Based on Min-Entropies

abstract:
  Fundamental results on secret sharing schemes (SSSs) are discussed in the
setting where security and share size are measured by (conditional)
min-entropies.
  We first formalize a unified framework of SSSs based on (conditional) R\'enyi
entropies, which includes SSSs based on Shannon and min entropies etc. as
special cases. By deriving the lower bound of share sizes in terms of R\'enyi
entropies based on the technique introduced by Iwamoto-Shikata, we obtain the
lower bounds of share sizes measured by min entropies as well as by Shannon
entropies in a unified manner.
  As the main contributions of this paper, we show two existential results of
non-perfect SSSs based on min-entropies under several important settings. We
first show that there exists a non-perfect SSS for arbitrary binary secret
information and arbitrary monotone access structure. In addition, for every
integers $k$ and $n$ ($k \le n$), we prove that the ideal non-perfect
$(k,n)$-threshold scheme exists even if the distribution of the secret is not
uniformly distributed.


title:
A Generalization of Threshold Saturation: Application to Spatially
  Coupled BICM-ID

abstract:
  Spatial coupling was proved to improve the belief-propagation (BP)
performance up to the maximum-a-posteriori (MAP) performance. This paper
addresses an extended class of spatially coupled (SC) systems. A potential
function is derived for characterizing a lower bound on the BP performance of
the extended SC systems, and shown to be different from the potential for the
conventional SC systems. This may imply that the BP performance for the
extended SC systems does not coincide with the MAP performance for the
corresponding uncoupled system. SC bit-interleaved coded modulation with
iterative decoding (BICM-ID) is also investigated as an application of the
extended SC systems.


title:
Astrophysical motivation for directed searches for a stochastic
  gravitational wave background

abstract:
  The nearby universe is expected to create an anisotropic stochastic
gravitational wave background (SGWB). Different algorithms have been developed
and implemented to search for isotropic and anisotropic SGWB. The aim of this
paper is to quantify the advantage of an optimal anisotropic search,
specifically comparing a point source with an isotropic background. Clusters of
galaxies appear as point sources to a network of ground based laser
interferometric detectors. The optimal search strategy for these sources is a
"directed radiometer search". We show that the flux of SGWB created by the
millisecond pulsars in the Virgo cluster produces a significantly stronger
signal than the nearly isotropic background of unresolved sources of the same
kind. We compute their strain power spectra for different cosmologies and
distribution of population over redshifts. We conclude that a localised source,
like the Virgo cluster, can be resolved from the isotropic background with very
high significance using the directed search algorithm. For backgrounds
dominated by nearby sources, up to redshift of about 3, we show that the
directed search for a localised source can have signal to noise ratio more than
that for the all sky integrated isotropic search.


title: Kernel Least Mean Square with Adaptive Kernel Size

abstract:
  Kernel adaptive filters (KAF) are a class of powerful nonlinear filters
developed in Reproducing Kernel Hilbert Space (RKHS). The Gaussian kernel is
usually the default kernel in KAF algorithms, but selecting the proper kernel
size (bandwidth) is still an open important issue especially for learning with
small sample sizes. In previous research, the kernel size was set manually or
estimated in advance by Silvermans rule based on the sample distribution. This
study aims to develop an online technique for optimizing the kernel size of the
kernel least mean square (KLMS) algorithm. A sequential optimization strategy
is proposed, and a new algorithm is developed, in which the filter weights and
the kernel size are both sequentially updated by stochastic gradient algorithms
that minimize the mean square error (MSE). Theoretical results on convergence
are also presented. The excellent performance of the new algorithm is confirmed
by simulations on static function estimation and short term chaotic time series
prediction.


title:
Gaussian-binary Restricted Boltzmann Machines on Modeling Natural Image
  Statistics

abstract:
  We present a theoretical analysis of Gaussian-binary restricted Boltzmann
machines (GRBMs) from the perspective of density models. The key aspect of this
analysis is to show that GRBMs can be formulated as a constrained mixture of
Gaussians, which gives a much better insight into the model's capabilities and
limitations. We show that GRBMs are capable of learning meaningful features
both in a two-dimensional blind source separation task and in modeling natural
images. Further, we show that reported difficulties in training GRBMs are due
to the failure of the training algorithm rather than the model itself. Based on
our analysis we are able to propose several training recipes, which allowed
successful and fast training in our experiments. Finally, we discuss the
relationship of GRBMs to several modifications that have been proposed to
improve the model.


title:
First passage statistics for aging diffusion in annealed and quenched
  disorder

abstract:
  Aging, the dependence of the dynamics of a physical process on the time $t_a$
since its original preparation, is observed in systems ranging from the motion
of charge carriers in amorphous semiconductors over the blinking dynamics of
quantum dots to the tracer dispersion in living biological cells. Here we study
the effects of aging on one of the most fundamental properties of a stochastic
process, the first passage dynamics. We find that for an aging continuous time
random walk process the scaling exponent of the density of first passage times
changes twice as the aging progresses and reveals an intermediate scaling
regime. The first passage dynamics depends on $t_a$ differently for
intermediate and strong aging. Similar crossovers are obtained for the first
passage dynamics for a confined and driven particle. Comparison to the motion
of an aged particle in the quenched trap model with a bias shows excellent
agreement with our analytical findings. Our results demonstrate how first
passage measurements can be used to unravel the age $t_a$ of a physical system.


title:
Noncovalent Functionalization of Boron Nitride Nanotubes in Aqueous
  Media

abstract:
  Boron nitride nanotubes (BNNTs) are of intense scientific interests due to
their unique physiochemical properties and prospective applications in various
nanotechnologies. A critical problem hampering the application processing of
BNNTs is the outer sidewall functionalization, which is primarily acquired to
lead BNNTs dispersible in various solvents. Furthermore, the surface of BNNTs
should be intelligently designed and precisely controlled to satisfy the
specific demands of different applications. For these purposes, covalent and
noncovalent approaches have been factually developed for opening up the key
door of applications. Importantly, wrapping the outermost sidewall of BNNTs
with either water-soluble polymers or biomolecules through weak noncovalent
interactions has been proved to be efficient for giving BNNTs considerable
dispersity in aqueous media, and endowing novel chemical functions to the BNNTs
with almost no change in their pristine physiochemical properties. This
contribution is made to summarize recent progresses, and further addresses the
future perspectives on the noncovalent functionalization of BNNTs for promoting
their application processing.


title:
Dynamics and microinstabilities at perpendicular collisionless shock: A
  comparison of large-scale two-dimensional full particle simulations with
  different ion to electron mass ratio

abstract:
  Large-scale two-dimensional (2D) full particle-in-cell simulations are
carried out for studying the relationship between the dynamics of a
perpendicular shock and microinstabilities generated at the shock foot. The
structure and dynamics of collisionless shocks are generally determined by
Alfven Mach number and plasma beta, while microinstabilities at the shock foot
are controlled by the ratio of the upstream bulk velocity to the electron
thermal velocity and the ratio of the plasma-to-cyclotron frequency. With a
fixed Alfven Mach number and plasma beta, the ratio of the upstream bulk
velocity to the electron thermal velocity is given as a function of the
ion-to-electron mass ratio. The present 2D full PIC simulations with a
relatively low Alfven Mach number (M_A ~ 6) show that the modified two-stream
instability is dominant with higher ion-to-electron mass ratios. It is also
confirmed that waves propagating downstream are more enhanced at the shock foot
near the shock ramp as the mass ratio becomes higher. The result suggests that
these waves play a role in the modification of the dynamics of collisionless
shocks through the interaction with shock front ripples.


title:
The "Missing Mass Problem" in Astronomy and the Need for a Modified Law
  of Gravity

abstract:
  Since the 1930s, astronomical observations have accumulated evidence that our
understanding of the dynamics of galaxies and groups of galaxies is grossly
incomplete: assuming the validity of Newton's law of gravity on astronomical
scales, the observed mass (stored in stars and interstellar gas) of stellar
systems can account only for roughly 10% of the dynamical (gravitating) mass
required to explain the high velocities of stars in those systems. The standard
approach to this "missing mass problem" has been the postulate of "dark
matter", meaning an additional, electromagnetically dark, matter component that
provides the missing mass. However, direct observational evidence for dark
matter has not been found to date. More importantly, astronomical observations
obtained during the last decade indicate that dark matter cannot explain the
kinematics of galaxies. Multiple observations show that the discrepancy between
observed and dynamical mass is a function of gravitational acceleration (or
field strength) but not of other parameters (size, rotation speed, etc.) of a
galaxy; the mass discrepancy appears below a characteristic and universal
acceleration ("Milgrom's constant"). Consequently, the idea of a modified law
of gravity, specifically the ansatz of Modified Newtonian Dynamics (MOND), is
becoming increasingly important in astrophysics. MOND has successfully
predicted various important empirical relations of galaxy dynamics, including
the famous Tully-Fisher and Faber-Jackson relations. MOND is found to be
consistent with stellar dynamics from binary stars to clusters of galaxies,
thus covering stellar systems spanning eight orders of magnitude in size and 14
orders of magnitude in mass. These developments have the potential to initiate
a paradigm shift from dark matter to a modified law of gravity as the physical
mechanism behind the missing mass problem.


title: On a generalization of criteria A and D for congruence of triangles

abstract:
  The conditions determining that two triangles are congruent play a basic role
in planimetry. By comparing not congruent triangles with respect to given sets
of corresponding elements it is important to discover if they have any common
geometric properties characterizing them. The present paper is devoted to an
answer of this question. We give a generalization of criteria A and D for
congruence of triangles and apply it to prove some selected geometric problems.


title: Nonlinear subsets of function spaces and spaceability

abstract:
  In this paper, we study the existence of infinite dimensional closed linear
subspaces of a rearrangement invariant space on [0,1] every nonzero element of
which does not belong to any included rearrangement invariant space of the same
class such that the inclusion operator is disjointly strictly singular. We
consider Lorentz, Marcinkiewicz and Orlicz spaces. The answer is affirmative
for Marcinkiewicz spaces and negative for Lorentz and Orlicz spaces. Also, the
same problem is studied for Nakano spaces assuming different hypothesis.


title:
Tuning the Quantum Phase Transition of Bosons in Optical Lattices via
  Periodic Modulation of s-Wave Scattering Length

abstract:
  We consider interacting bosons in a 2D square and a 3D cubic optical lattice
with a periodic modulation of the s-wave scattering length. At first we map the
underlying periodically driven Bose-Hubbard model for large enough driving
frequencies approximately to an effective time-independent Hamiltonian with a
conditional hopping. Combining different analytical approaches with quantum
Monte Carlo simulations then reveals that the superfluid-Mott insulator quantum
phase transition still exists despite the periodic driving and that the
location of the quantum phase boundary turns out to depend quite sensitively on
the driving amplitude. A more detailed quantitative analysis shows even that
the effect of driving can be described within the usual Bose-Hubbard model
provided that the hopping is rescaled appropriately with the driving amplitude.
This finding indicates that the Bose-Hubbard model with a periodically driven
s-wave scattering length and the usual Bose-Hubbard model belong to the same
universality class from the point of view of critical phenomena.


title:
The Noether-Lefschetz Problem and Gauge-Group-Resolved Landscapes:
  F-Theory on K3 x K3 as a Test Case

abstract:
  Four-form flux in F-theory compactifications not only stabilizes moduli, but
gives rise to ensembles of string vacua, providing a scientific basis for a
stringy notion of naturalness. Of particular interest in this context is the
ability to keep track of algebraic information (such as the gauge group)
associated with individual vacua while dealing with statistics. In the present
work, we aim to clarify conceptual issues and sharpen methods for this purpose,
using compactification on ${\rm K3} \times {\rm K3}$ as a test case. Our first
approach exploits the connection between the stabilization of complex structure
moduli and the Noether-Lefschetz problem. Compactification data for F-theory,
however, involve not only a four-fold (with a given complex structure) $Y_4$
and a flux on it, but also an elliptic fibration morphism $Y_4 \longrightarrow
B_3$, which makes this problem complicated. The heterotic-F-theory duality
indicates that elliptic fibration morphisms should be identified modulo
isomorphism. Based on this principle, we explain how to count F-theory vacua on
${\rm K3} \times {\rm K3}$ while keeping the gauge group information.
Mathematical results reviewed/developed in our companion paper are exploited
heavily. With applications to more general four-folds in mind, we also clarify
how to use Ashok-Denef-Douglas' theory of the distribution of flux vacua in
order to deal with statistics of sub-ensembles tagged by a given set of
algebraic/topological information. As a side remark, we extend the
heterotic/F-theory duality dictionary on flux quanta and elaborate on its
connection to the semistable degeneration of a K3 surface.


title: Composition of inverse problems with a given logical structure

abstract:
  The paper presents a method for obtaining problems whose conclusions contain
disjunctive propositions. These problems constitute a version of inverse
problems with a given logical structure. The logical models in the groups of
problems studied have been interpreted comprehensively. Equivalent problems
have been given by keeping or not keeping the condition of homogeneity in their
conclusion.


title: Applications of the Gauss-Jordan algorithm, done right

abstract:
  Computer Algebra systems are widely spread because of some of their
remarkable features such as their ease of use and performance. Nonetheless,
this focus on performance sometimes leads to unwanted consequences: algorithms
and computations are implemented and carried out in a way which is sometimes
not transparent to the users, and that can lead to unexpected failures. In this
paper we present a formalisation in a proof assistant system of a \emph{naive}
version of the Gauss-Jordan algorithm, with explicit proofs of some of its
applications, and additionally a process to obtain versions of this algorithm
in two different functional languages (SML and Haskell) by means of code
generation techniques from the verified algorithm. The obtained programs are
then applied to test cases, which, despite the simplicity of the original
algorithm, have shown remarkable features in comparison to some Computer
Algebra systems, such as Mathematica\textsuperscript{\textregistered} (where
some of these computations are even incorrect), or Sage (in comparison to which
the generated programs show a compelling performance). The aim of the paper is
to show that, with the current technology in Theorem Proving, formalising
Linear Algebra procedures is a challenging but rewarding task, which provides
programs that can be compared in some aspects to \emph{state of the art}
procedures in Computer Algebra systems, and whose correctness is formally
proved.


title: Nodal domains of the equilateral triangle billiard

abstract:
  We characterise the eigenfunctions of an equilateral triangle billiard in
terms of its nodal domains. The number of nodal domains has a quadratic form in
terms of the quantum numbers, with a non-trivial number-theoretic factor. The
patterns of the eigenfunctions follow a group-theoretic connection in a way
that makes them predictable as one goes from one state to another. Extensive
numerical investigations bring out the distribution functions of the mode
number and signed areas. The statistics of the boundary intersections is also
treated analytically. Finally, the distribution functions of the nodal loop
count and the nodal counting function are shown to contain information about
the classical periodic orbits using the semiclassical trace formula. We believe
that the results belong generically to non-separable systems, thus extending
the previous works which are concentrated on separable and chaotic systems.


title:
Orbital Dependent Electronic Masses in Ce Heavy Fermion Materials
  studied via Gutzwiller Density Functional Theory

abstract:
  A series of Cerium based heavy fermion materials is studied using a
combination of local density functional theory and many-body Gutzwiller
approximation. Computed orbial dependent electronic mass enhancements
parameters are compared with available data extracted from measured values of
the Sommerfeld coefficient. The Gutzwiller density functional theory is shown
to remarkably follow the trends across a variety of Ce compounds, and to give
important insights on orbital selective mass renormalizations that allows a
better understanding of wide spread of data.


title:
Galois cohomology of reductive algebraic groups over the field of real
  numbers

abstract:
  We describe functorially the first Galois cohomology set $H^1({\mathbb R},G)$
of a connected reductive algebraic group $G$ over the field $\mathbb R$ of real
numbers in terms of a certain action of the Weyl group on the real points of
order dividing 2 of the maximal torus containing a maximal compact torus.
  This result was announced with a sketch of proof in the author's 1988 note.
Here we give a detailed proof.


title: Spin-Orbit Coupling in Deformed Harmonic Traps

abstract:
  We consider a two-dimensional system of harmonically trapped particles with
pseudo-spin-$\frac{1}{2}$ degree of freedom. This degree of freedom is coupled
to the particle's momentum via the so-called Rashba spin-orbit interaction. We
present our numerical results for a single-particle and few-particle systems,
assuming the repulsive interparticle interaction to be of zero range.


title: Comparison results for the Stokes equations

abstract:
  This paper enfolds a medius analysis for the Stokes equations and compares
different finite element methods (FEMs). A first result is a best approximation
result for a P1 non-conforming FEM. The main comparison result is that the
error of the P2-P0-FEM is a lower bound to the error of the Bernardi-Raugel (or
reduced P2-P0) FEM, which is a lower bound to the error of the P1
non-conforming FEM, and this is a lower bound to the error of the MINI-FEM. The
paper discusses the converse direction, as well as other methods such as the
discontinuous Galerkin and pseudostress FEMs.
  Furthermore this paper provides counterexamples for equivalent convergence
when different pressure approximations are considered. The mathematical
arguments are various conforming companions as well as the discrete inf-sup
condition.


title: On the minimax principle for Coulomb-Dirac operators

abstract:
  Let q and v be symmetric sesquilinear forms such that v is a form
perturbation of q. Then we can associate a unique self-adjoint operator B to q+
v. Assuming that B has a gap (a, b) in the essential spectrum, we prove a
minimax principle for the eigenvalues of B in (a, b) using a suitable
orthogonal decomposition of the domain of q. This allows us to justify two
minimax characterisations of eigenvalues in the gap of three-dimensional Dirac
operators with electrostatic potentials having strong Coulomb singularities.


title: Commutativity up to a factor for bounded and unbounded operators

abstract:
  In this paper, we further investigate the problem of commutativity up to a
factor (or $\lambda$-commutativity) in the setting of bounded and unbounded
linear operators in a complex Hilbert space. The results are based on a new
approach to the problem. We finish the paper by a conjecture on the
commutativity of self-adjoint operators.


title: ESPRESSO: The next European exoplanet hunter

abstract:
  The acronym ESPRESSO stems for Echelle SPectrograph for Rocky Exoplanets and
Stable Spectroscopic Observations; this instrument will be the next VLT high
resolution spectrograph. The spectrograph will be installed at the
Combined-Coud\'e Laboratory of the VLT and linked to the four 8.2 m Unit
Telescopes (UT) through four optical Coud\'e trains. ESPRESSO will combine
efficiency and extreme spectroscopic precision. ESPRESSO is foreseen to achieve
a gain of two magnitudes with respect to its predecessor HARPS, and to improve
the instrumental radial-velocity precision to reach the 10 cm/s level. It can
be operated either with a single UT or with up to four UTs, enabling an
additional gain in the latter mode. The incoherent combination of four
telescopes and the extreme precision requirements called for many innovative
design solutions while ensuring the technical heritage of the successful HARPS
experience. ESPRESSO will allow to explore new frontiers in most domains of
astrophysics that require precision and sensitivity. The main scientific
drivers are the search and characterization of rocky exoplanets in the
habitable zone of quiet, nearby G to M-dwarfs and the analysis of the
variability of fundamental physical constants. The project passed the final
design review in May 2013 and entered the manufacturing phase. ESPRESSO will be
installed at the Paranal Observatory in 2016 and its operation is planned to
start by the end of the same year.


title:
Hamming's Original Paper Rewritten in Symbolic Form: A Preamble to
  Coding Theory

abstract:
  In this note we try to bring out the ideas of Hamming's classic paper on
coding theory in a form understandable by undergraduate students of
mathematics.


title: Photometric decomposition of mergers in disk galaxies

abstract:
  Several observational studies and numerical simulations suggest that mergers
must contribute to the evolution of galaxies; however, the role that they play
is not yet fully understood. In this paper we study a sample of 52 double
nucleus disk galaxies that are considered as candidates for a minor merger
event. The luminosity of each of the nuclei and their relative separation are
derived from a multi-component photometric fit of the galaxies in the Sloan
Digital Sky Survey optical images. We find that the nuclei in most of the
sources have projected separations $\leq$ 4 kpc. The ratio of nuclear
luminosities indicates that most of the systems are likely in the coalescence
stage of a major merger. This is supported by the existence of a single galaxy
disk in 65% of the systems studied and the finding of a correlation between
nuclear luminosity and host luminosity for the single-disk systems: those
sources fitted with as single disk are in a more evolved stage of the merger
and present an enhancement of the nuclear luminosity compared to the
double-disk systems, as expected from simulations of galaxy mergers. Finally,
we identify a sample of 19 double nucleus disk galaxies in which the two nuclei
are physically separated by $\leq1$ kpc and constitute thus a sample of sub-kpc
binary AGN candidates.


title:
The Shape of the Search Tree for the Maximum Clique Problem, and the
  Implications for Parallel Branch and Bound

abstract:
  Finding a maximum clique in a given graph is one of the fundamental NP-hard
problems. We compare two multi-core thread-parallel adaptations of a
state-of-the-art branch and bound algorithm for the maximum clique problem, and
provide a novel explanation as to why they are successful. We show that load
balance is sometimes a problem, but that the interaction of parallel search
order and the most likely location of solutions within the search space is
often the dominating consideration. We use this explanation to propose a new
low-overhead, scalable work splitting mechanism. Our approach uses explicit
early diversity to avoid strong commitment to the weakest heuristic advice, and
late resplitting for balance. More generally, we argue that for branch and
bound, parallel algorithm design should not be performed independently of the
underlying sequential algorithm.


title: Excited state entanglement in homogeneous fermionic chains

abstract:
  We study the Renyi entanglement entropy of an interval in a periodic
fermionic chain for a general eigenstate of a free, translational invariant
Hamiltonian. In order to analytically compute the entropy we use two technical
tools. The first one is used to reduce logarithmically the complexity of the
problem and the second one to compute the R\'enyi entropy of the chosen
subsystem. We introduce new strategies to perform the computations, derive new
expressions for the entropy of these general states and show the perfect
agreement of the analytical computations and the numerical outcome. Finally we
discuss the physical interpretation of our results and generalise them to
compute the entanglement entropy for a fragment of a fermionic ladder.

categories: quant-ph cond-mat.stat-mech math-ph math.MP


title: Temporal flooding of regular islands by chaotic wave packets

abstract:
  We investigate the time evolution of wave packets in systems with a mixed
phase space where regular islands and chaotic motion coexist. For wave packets
started in the chaotic sea on average the weight on a quantized torus of the
regular island increases due to dynamical tunneling. This flooding weight
initially increases linearly and saturates to a value which varies from torus
to torus. We demonstrate for the asymptotic flooding weight universal scaling
with an effective tunneling coupling for quantum maps and the mushroom
billiard. This universality is reproduced by a suitable random matrix model.


title: Study of the N N eta' production with COSY-11

abstract:
  We describe a new high precision measurement of the production cross-section
for the eta' meson in proton-proton collisions for five beam momenta at low
access energy region Q conducted at the COSY-11 detection system together with
an updated results of all other previous measurements of cross-section for
(pp-->pp eta') at COSY-11.


title:
Joint relative position and velocity estimation for an anchorless
  network of mobile nodes

abstract:
  Localization is a fundamental challenge for any wireless network of nodes, in
particular when the nodes are mobile. We present an extension of the classical
Multidimensional scaling (MDS) for an anchorless network of mobile nodes,
wherein the solutions to the time-varying relative node positions are shown to
lie in the derivatives of the time-varying inter-nodal pairwise distances.
Moreover, we show that the relative position of a mobile node at each time
instance is only dependent on the initial relative position, relative velocity
and a common rotation matrix of the respective node, which are estimated using
MDS-like and least squares estimators. Simulations are conducted to evaluate
the performance of the proposed solutions and the results are presented.


title: The importance of jet bending in gamma-ray AGN - revisited

abstract:
  We investigate the hypothesis that {\gamma}-ray-quiet AGN have a larger
tendency for jet bending than {\gamma}-ray-loud AGN, revisiting the analysis of
Tingay, Murphy & Edwards (1998). We perform a statistical analysis using a
large sample of 351 radio-loud AGN along with {\gamma}-ray identifications from
the Fermi Large Area Telescope (LAT). Our results show no statistically
significant differences in jet-bending properties between {\gamma}-ray-loud and
{\gamma}-ray-quiet populations, indicating that jet bending is not a
significant factor for {\gamma}-ray detection in AGN.


title:
Asymptotic Behaviour and Cyclic Properties of Weighted Shifts on
  Directed Trees

abstract:
  In this paper we investigate a new class of operators called weighted shifts
on directed trees introduced recently in [Z. J. Jablonski, I. B. Jung and J.
Stochel, A Non-hyponormal Operator Generating Stieltjes Moment Sequences, J.
Funct. Anal. 262 (2012), no. 9, 3946--3980.]. This class is a natural
generalization of the so called weighted bilateral, unilateral and backward
shift operators. In the first part of the paper we calculate the asymptotic
limit and the isometric asymptote of a contractive weighted shift on a directed
tree and that of the adjoint. Then we use the asymptotic behaviour and
similarity properties to deal with cyclicity. We also show that a weighted
backward shift operator is cyclic if and only if there is at most one zero
weight.


title:
Crystal field and related phenomena in hexagonal close-packed H2 and D2
  under pressure

abstract:
  The lattice distortion parameter (the deviation of the c/a ratio from the
ideal value 1.633), orientational order parameter, and crystal-field parameter
in hexagonal close-packed (hcp) lattice of p-H2, o-D2 and n-H2 are calculated
using the semi-empirical lattice-dynamic approach. It is shown that the lattice
distortion in the J-even species is two order of magnitude smaller compared
with that found in n-H2, and n-D2. The difference is due to the splitting of
the J-odd rotational levels in the J-even - J-odd mixtures.


title: Crawling on directional surfaces

abstract:
  In this paper we study crawling locomotion based on directional frictional
interactions, namely, frictional forces that are sensitive to the sign of the
sliding velocity. Surface interactions of this type are common in biology,
where they arise from the presence of inclined hairs or scales at the
crawler/substrate interface, leading to low resistance when sliding 'along the
grain', and high resistance when sliding 'against the grain'. This asymmetry
can be exploited for locomotion, in a way analogous to what is done in
cross-country skiing (classic style, diagonal stride). We focus on a model
system, namely, a continuous one-dimensional crawler and provide a detailed
study of the motion resulting from several strategies of shape change. In
particular, we provide explicit formulae for the displacements attainable with
reciprocal extensions and contractions (breathing), or through the propagation
of extension or contraction waves. We believe that our results will prove
particularly helpful for the study of biological crawling motility and for the
design of bio-mimetic crawling robots.


title: Decays of polarized top quarks to lepton, neutrino and jets at NLO QCD

abstract:
  We compute the differential and total rate of the semileptonic decay of
polarized top-quarks $t\to \ell \nu_\ell + b{\rm jet} + {\rm jet}$ at
next-to-leading order (NLO) in the QCD coupling with an off-shell intermediate
$W$ boson. We present several normalized distributions, in particular those
that reflect the $t$-spin analyzing powers of the lepton, the b-jet and the
$W^+$ boson at LO and NLO QCD.


title:
Joint non-linear ranging and affine synchronization basis for a network
  of mobile nodes

abstract:
  Synchronization and localization are critical challenges for the coherent
functioning of a wireless network of mobile nodes. In this paper, a novel joint
non-linear range and affine time model is presented based on two way time stamp
exchanges, extending an existing affine time-range model. For a pair of nodes,
a closed form pairwise least squares solution is proposed for estimating
pairwise range parameters, namely relative range, range rate and rate of range
rate between the nodes, in addition to estimating the clock skews and the clock
offsets. Extending these pair wise solutions to network wide ranging and clock
synchronization, we present a central data fusion based global least squares
solution. Furthermore, a new Constrained Cramer Rao Bound (CCRB) is derived for
the joint time-range model and the proposed algorithms are shown to approach
the theoretical limits.


title:
Mixing and segregation of ring polymers: spatial confinement and
  molecular crowding effects

abstract:
  During the life cycle of bacterial cells the non-mixing of the two
ring-shaped daughter genomes is an important prerequisite for the cell division
process. Mimicking the environments inside highly crowded biological cells, we
study the dynamics and statistical behaviour of two flexible ring polymers in
the presence of cylindrical confinement and crowding molecules. From extensive
computer simulations we determine the degree of ring-ring overlap and the
number of inter-monomer contacts for varying volume fractions $\phi$ of
crowders. We also examine the entropic de-mixing of polymer rings in the
presence of mobile crowders and determine the characteristic times of the
internal polymer dynamics. Effects of the ring length on ring-ring overlap are
also analysed. In particular, on systematic variation of the fraction of
crowding molecules a $(1-\phi)$-scaling is found for the ring-ring overlap
length along the cylinder axis, and a non-monotonic dependence of the 3D
ring-ring contact number is predicted. Our results help to rationalise the
implications of macromolecular crowding for circular DNA molecules in confined
spaces inside bacteria as well as in localised cellular compartments inside
eukaryotic cells.


title: Light-cone gravity in AdS$_{4}$

abstract:
  We obtain a closed form expression for the Action describing pure gravity, in
light-cone gauge, in a four-dimensional Anti de Sitter background. We perform a
perturbative expansion of this closed form result to extract the cubic
interaction vertex in this gauge.


title:
Accelerated Assistant to SubOptimum Receiver for Multi Carrier Code
  Division Multiple Access System

abstract:
  The Multiple Input Multiple output system are considered to be the strongest
candidate for the maximum utilization of available bandwidth. In this paper,
the MIMO system with the combination of Multi-Carrier Code Division Multiple
Access and Space Time Coding using the Alamoutis scheme is considered. A
Genetic Algorithm based receiver with an exceptional relationship between
filter weights while detecting symbols is proposed. This scheme has better
Convergence Rate and Bit Error Rate than the Fast-LMS Adaptive receiver.


title: Turbulent channel without boundaries: The periodic Kolmogorov flow

abstract:
  The Kolmogorov flow provides an ideal instance of a virtual channel flow: It
has no boundaries, but nevertheless it possesses well defined mean flow in each
half-wavelength. We exploit this remarkable feature for the purpose of
investigating the interplay between the mean flow and the turbulent drag of the
bulk flow. By means of a set of direct numerical simulations at increasing
Reynolds number we show the dependence of the bulk turbulent drag on the
amplitude of the mean flow. Further, we present a detailed analysis of the
scale-by-scale energy balance, which describes how kinetic energy is
redistributed among different regions of the flow while being transported
toward small dissipative scales. Our results allow us to obtain an accurate
prediction for the spatial energy transport at large scales.


title:
Observational evidence of torus instability as trigger mechanism for
  coronal mass ejections: the 2011 August 4 filament eruption

abstract:
  Solar filaments are magnetic structures often observed in the solar
atmosphere and consist of plasma that is cooler and denser than their
surroundings. They are visible for days -- and even weeks -- which suggests
that they are often in equilibrium with their environment before disappearing
or erupting. Several eruption models have been proposed that aim to reveal what
mechanism causes (or triggers) these solar eruptions. Validating these models
through observations represents a fundamental step in our understanding of
solar eruptions. We present an analysis of the observation of a filament
eruption that agrees with the torus instability model. This model predicts that
a magnetic flux rope embedded in an ambient field undergoes an eruption when
the axis of the flux rope reaches a critical height that depends on the
topology of the ambient field. We use the two vantage points of SDO and STEREO
to reconstruct the three-dimensional shape of the filament, to follow its
morphological evolution and to determine its height just before eruption. The
magnetograms acquired by SDO/HMI are used to infer the topology of the ambient
field and to derive the critical height for the onset of the torus instability.
Our analysis shows that the torus instability is the trigger of the eruption.
We also find that some pre-eruptive processes, such as magnetic reconnection
during the observed flares and flux cancellation at the neutral line,
facilitated the eruption by bringing the filament to a region where the
magnetic field was more vulnerable to the torus instability.


title: An algebraically solvable PT-symmetric potential with broken symmetry

abstract:
  The spectrum of a one-dimensional Hamiltonian with potential $V(x)=ix^2$ for
negative $x$ and $V(x)=-ix^2$ for positive $x$ is analyzed. The Schr\"odinger
equation is algebraically solvable and the eigenvalues are obtained as the
zeros of an expression explicitly given in terms of Gamma functions. The
spectrum consists of one real eigenvalue and an infinite set of pairs of
complex conjugate eigenvalues.


title:
Existence and uniqueness for stochastic 2D Euler flows with bounded
  vorticity

abstract:
  Strong existence and pathwise uniqueness of solutions with
$L^{\infty}$-vorticity of 2D stochastic Euler equations is proved. The noise is
multiplicative and involves first derivatives. A Lagrangian approach is
implemented, where a stochastic flow solving a nonlinear flow equation is
constructed. Stability under regularization is also proved.


title: Tensor product of left polaroid operators

abstract:
  A Banach space operator $T\in B(X)$ is left polaroid if for each
$\lambda\in\hbox{iso}\sigma_a(T)$ there is an integer $d(\lambda)$ such that
asc $(T-\lambda)=d(\lambda)<\infty$ and $(T-\lambda)^{d(\lambda)+1}X$ is
closed; $T$ is finitely left polaroid if asc $(T-\lambda)<\infty$,
$(T-\lambda)X$ is closed and $\dim(T-\lambda)^{-1}(0)<\infty$ at each
$\lambda\in\hbox{iso }\sigma_a(T)$. The left polaroid property transfers from
$A$ and $B$ to their tensor product $A\otimes B$, hence also from $A$ and $B^*$
to the left-right multiplication operator $\tau_{AB}$, for Hilbert space
operators; an additional condition is required for Banach space operators. The
finitely left polaroid property transfers from $A$ and $B$ to their tensor
product $A\otimes B$ if and only if $0\not\in\hbox{iso}\sigma_a(A\otimes B)$; a
similar result holds for $\tau_{AB}$ for finitely left polaroid $A$ and $B^*$.