pinecone/core-2020-05-10-deduplication huggingface dataset:
Multi-Level quasi-Newton methods for the partitioned simulation of fluid-structure interaction

In previous work of the authors, Fourier stability analyses have been performed of Gauss-Seidel iterations between the flow solver and the structural solver in a partitioned fluid-structure interaction simulation. These analyses of the flow in an elastic tube demonstrated that only a number of Fourier modes in the error on the interface displacement are unstable. Moreover, the modes with a low wave number are most unstable and these modes can be resolved on a coarser grid. Therefore, a new class of quasi-Newton methods with more than one grid level is introduced. Numerical experiments show a significant reduction in run time
Design and construction of a configurable full-field range imaging system for mobile robotic applications

Mobile robotic devices rely critically on extrospection sensors to determine the range to objects in the robot’s operating environment. This provides the robot with the ability both to navigate safely around obstacles and to map its environment and hence facilitate path planning and navigation. There is a requirement for a full-field range imaging system that can determine the range to any obstacle in a camera lens’ field of view accurately and in real-time. This paper details the development of a portable full-field ranging system whose bench-top version has demonstrated sub-millimetre precision. However, this precision required non-real-time acquisition rates and expensive hardware. By iterative replacement of components, a portable, modular and inexpensive version of this full-field ranger has been constructed, capable of real-time operation with some (user-defined) trade-off with precision
The World as Evolving Information

This paper discusses the benefits of describing the world as information,
especially in the study of the evolution of life and cognition. Traditional
studies encounter problems because it is difficult to describe life and
cognition in terms of matter and energy, since their laws are valid only at the
physical scale. However, if matter and energy, as well as life and cognition,
are described in terms of information, evolution can be described consistently
as information becoming more complex.
  The paper presents eight tentative laws of information, valid at multiple
scales, which are generalizations of Darwinian, cybernetic, thermodynamic,
psychological, philosophical, and complexity principles. These are further used
to discuss the notions of life, cognition and their evolution.Comment: 16 pages. Extended version, three more laws of information, two
  classifications, and discussion added. To be published (soon) in
  International Conference on Complex Systems 2007 Proceeding
Efficient Triangle Counting in Large Graphs via Degree-based Vertex
  Partitioning

The number of triangles is a computationally expensive graph statistic which
is frequently used in complex network analysis (e.g., transitivity ratio), in
various random graph models (e.g., exponential random graph model) and in
important real world applications such as spam detection, uncovering of the
hidden thematic structure of the Web and link recommendation. Counting
triangles in graphs with millions and billions of edges requires algorithms
which run fast, use small amount of space, provide accurate estimates of the
number of triangles and preferably are parallelizable.
  In this paper we present an efficient triangle counting algorithm which can
be adapted to the semistreaming model. The key idea of our algorithm is to
combine the sampling algorithm of Tsourakakis et al. and the partitioning of
the set of vertices into a high degree and a low degree subset respectively as
in the Alon, Yuster and Zwick work treating each set appropriately. We obtain a
running time $O \left(m + \frac{m^{3/2} \Delta \log{n}}{t \epsilon^2} \right)$
and an $\epsilon$ approximation (multiplicative error), where $n$ is the number
of vertices, $m$ the number of edges and $\Delta$ the maximum number of
triangles an edge is contained.
  Furthermore, we show how this algorithm can be adapted to the semistreaming
model with space usage $O\left(m^{1/2}\log{n} + \frac{m^{3/2} \Delta \log{n}}{t
\epsilon^2} \right)$ and a constant number of passes (three) over the graph
stream. We apply our methods in various networks with several millions of edges
and we obtain excellent results. Finally, we propose a random projection based
method for triangle counting and provide a sufficient condition to obtain an
estimate with low variance.Comment: 1) 12 pages 2) To appear in the 7th Workshop on Algorithms and Models
  for the Web Graph (WAW 2010
Component Evolution in General Random Intersection Graphs

Random intersection graphs (RIGs) are an important random structure with
applications in social networks, epidemic networks, blog readership, and
wireless sensor networks. RIGs can be interpreted as a model for large randomly
formed non-metric data sets. We analyze the component evolution in general
RIGs, and give conditions on existence and uniqueness of the giant component.
Our techniques generalize existing methods for analysis of component evolution:
we analyze survival and extinction properties of a dependent, inhomogeneous
Galton-Watson branching process on general RIGs. Our analysis relies on
bounding the branching processes and inherits the fundamental concepts of the
study of component evolution in Erd\H{o}s-R\'enyi graphs. The major challenge
comes from the underlying structure of RIGs, which involves its both the set of
nodes and the set of attributes, as well as the set of different probabilities
among the nodes and attributes
Multiplicative Attribute Graph Model of Real-World Networks

Large scale real-world network data such as social and information networks
are ubiquitous. The study of such social and information networks seeks to find
patterns and explain their emergence through tractable models. In most
networks, and especially in social networks, nodes have a rich set of
attributes (e.g., age, gender) associated with them.
  Here we present a model that we refer to as the Multiplicative Attribute
Graphs (MAG), which naturally captures the interactions between the network
structure and the node attributes. We consider a model where each node has a
vector of categorical latent attributes associated with it. The probability of
an edge between a pair of nodes then depends on the product of individual
attribute-attribute affinities. The model yields itself to mathematical
analysis and we derive thresholds for the connectivity and the emergence of the
giant connected component, and show that the model gives rise to networks with
a constant diameter. We analyze the degree distribution to show that MAG model
can produce networks with either log-normal or power-law degree distributions
depending on certain conditions.Comment: 33 pages, 6 figure
Teaching computer language handling - From compiler theory to meta-modelling

Published version of a chapter in the book: Generative and Transformational Techniques in Software Engineering III. Also available from the publisher at: http://dx.doi.org/10.1007/978-3-642-18023-1_14Most universities teach computer language handling by mainly focussing on compiler theory, although MDA (model-driven architecture) and meta-modelling are increasingly important in the software industry as well as in computer science. In this article, we investigate how traditional compiler theory compares to meta-modelling with regard to formally defining the different aspects of a language, and how we can expand the focus in computer language handling courses to also include meta-model-based approaches. We give an outline of a computer language handling course that covers both paradigms, and share some experiences from running a course based on this outline at the University of Agder
Using level-2 fuzzy sets to combine uncertainty and imprecision in fuzzy regions

In many applications, spatial data need to be considered but are prone to uncertainty or imprecision. A fuzzy region - a fuzzy set over a two dimensional domain - allows the representation of such imperfect spatial data. In the original model, points of the fuzzy region where treated independently, making it impossible to model regions where groups of points should be considered as one basic element or subregion. A first extension overcame this, but required points within a group to have the same membership grade. In this contribution, we will extend this further, allowing a fuzzy region to contain subregions in which not all points have the same membership grades. The concept can be used as an underlying model in spatial applications, e.g. websites showing maps and requiring representation of imprecise features or websites with routing functions needing to handle concepts as walking distance or closeby
Towards the interoperability of computerised guidelines and electronic health records: an experiment with openEHR archetypes and a chronic heart failure guideline

Clinical guidelines contain recommendations based on the best empirical evidence available at the moment. There is a wide consensus about the benefits of guidelines and about the fact that they should be deployed through clinical information systems, making them available during clinical consultations. However, one of the main obstacles to this integration is the interaction with the electronic healthrecord system. With the aim of solving the interoperability problems of guideline systems, we have investigated the utilisation of the openEHR standardisation proposal in the context of one of the existing guideline representation languages. Concretely, we have designed a collection of archetypes to be used within a chronic heart failure guideline. The main contribution of our work is the utilisation of openEHR archetypes in the framework of guideline representation languages. Other contributions include both the concrete set of archetypes that we have selected and the methodological approach that we have followed to obtain itThis work has been supported by Fundaci´o Caixa Castell´o-Bancaixa, through the research project P11B2009-3
Models for Heavy-tailed Asset Returns

Many of the concepts in theoretical and empirical finance developed over the past decades – including the classical portfolio theory, the Black-Scholes-Merton option pricing model or the RiskMetrics variance-covariance approach to VaR – rest upon the assumption that asset returns follow a normal distribution. But this assumption is not justified by empirical data! Rather, the empirical observations exhibit excess kurtosis, more colloquially known as fat
tails or heavy tails. This chapter is intended as a guide to heavy-tailed models. We first describe the historically oldest heavy-tailed model – the stable laws. Next, we briefly characterize their recent lighter-tailed generalizations, the so-called truncated and tempered stable distributions. Then we study the class of generalized hyperbolic laws, which – like tempered stable distributions – can be classified somewhere between infinite variance stable laws and the Gaussian distribution. Finally, we provide numerical examples.
Building Loss Models

This paper is intended as a guide to building insurance risk (loss) models. A typical model for insurance risk, the so-called collective risk model, treats the aggregate loss as having a compound distribution with two main components: one characterizing the arrival of claims and another describing the severity (or size) of loss resulting from the occurrence of a claim. In this paper we first present efficient simulation algorithms for several classes of claim arrival processes. Then we review a collection of loss distributions and present methods that can be used to assess the goodness-of-fit of the claim size distribution. The collective risk model is often used in health insurance and in general insurance, whenever the main risk components are the number of insurance claims and the amount of the claims. It can also be used for modeling other non-insurance
product risks, such as credit and operational risk.
Sawja: Static Analysis Workshop for Java

Static analysis is a powerful technique for automatic verification of
programs but raises major engineering challenges when developing a full-fledged
analyzer for a realistic language such as Java. This paper describes the Sawja
library: a static analysis framework fully compliant with Java 6 which provides
OCaml modules for efficiently manipulating Java bytecode programs. We present
the main features of the library, including (i) efficient functional
data-structures for representing program with implicit sharing and lazy
parsing, (ii) an intermediate stack-less representation, and (iii) fast
computation and manipulation of complete programs
Generalized self-testing and the security of the 6-state protocol

Self-tested quantum information processing provides a means for doing useful
information processing with untrusted quantum apparatus. Previous work was
limited to performing computations and protocols in real Hilbert spaces, which
is not a serious obstacle if one is only interested in final measurement
statistics being correct (for example, getting the correct factors of a large
number after running Shor's factoring algorithm). This limitation was shown by
McKague et al. to be fundamental, since there is no way to experimentally
distinguish any quantum experiment from a special simulation using states and
operators with only real coefficients.
  In this paper, we show that one can still do a meaningful self-test of
quantum apparatus with complex amplitudes. In particular, we define a family of
simulations of quantum experiments, based on complex conjugation, with two
interesting properties. First, we are able to define a self-test which may be
passed only by states and operators that are equivalent to simulations within
the family. This extends work of Mayers and Yao and Magniez et al. in
self-testing of quantum apparatus, and includes a complex measurement. Second,
any of the simulations in the family may be used to implement a secure 6-state
QKD protocol, which was previously not known to be implementable in a
self-tested framework.Comment: To appear in proceedings of TQC 201
Geometric Entanglement of Symmetric States and the Majorana
  Representation

Permutation-symmetric quantum states appear in a variety of physical
situations, and they have been proposed for quantum information tasks. This
article builds upon the results of [New J. Phys. 12, 073025 (2010)], where the
maximally entangled symmetric states of up to twelve qubits were explored, and
their amount of geometric entanglement determined by numeric and analytic
means. For this the Majorana representation, a generalization of the Bloch
sphere representation, can be employed to represent symmetric n qubit states by
n points on the surface of a unit sphere. Symmetries of this point distribution
simplify the determination of the entanglement, and enable the study of quantum
states in novel ways. Here it is shown that the duality relationship of
Platonic solids has a counterpart in the Majorana representation, and that in
general maximally entangled symmetric states neither correspond to anticoherent
spin states nor to spherical designs. The usability of symmetric states as
resources for measurement-based quantum computing is also discussed.Comment: 10 pages, 8 figures; submitted to Lecture Notes in Computer Science
  (LNCS
Teleportation of a quantum state of a spatial mode with a single massive
  particle

Mode entanglement exists naturally between regions of space in ultra-cold
atomic gases. It has, however, been debated whether this type of entanglement
is useful for quantum protocols. This is due to a particle number
superselection rule that restricts the operations that can be performed on the
modes. In this paper, we show how to exploit the mode entanglement of just a
single particle for the teleportation of an unknown quantum state of a spatial
mode. We detail how to overcome the superselection rule to create any initial
quantum state and how to perform Bell state analysis on two of the modes. We
show that two of the four Bell states can always be reliably distinguished,
while the other two have to be grouped together due to an unsatisfied phase
matching condition. The teleportation of an unknown state of a quantum mode
thus only succeeds half of the time.Comment: 12 pages, 1 figure, this paper was presented at TQC 2010 and extends
  the work of Phys. Rev. Lett. 103, 200502 (2009
On quantum estimation, quantum cloning and finite quantum de Finetti
  theorems

This paper presents a series of results on the interplay between quantum
estimation, cloning and finite de Finetti theorems. First, we consider the
measure-and-prepare channel that uses optimal estimation to convert M copies
into k approximate copies of an unknown pure state and we show that this
channel is equal to a random loss of all but s particles followed by cloning
from s to k copies. When the number k of output copies is large with respect to
the number M of input copies the measure-and-prepare channel converges in
diamond norm to the optimal universal cloning. In the opposite case, when M is
large compared to k, the estimation becomes almost perfect and the
measure-and-prepare channel converges in diamond norm to the partial trace over
all but k systems. This result is then used to derive de Finetti-type results
for quantum states and for symmetric broadcast channels, that is, channels that
distribute quantum information to many receivers in a permutationally invariant
fashion. Applications of the finite de Finetti theorem for symmetric broadcast
channels include the derivation of diamond-norm bounds on the asymptotic
convergence of quantum cloning to state estimation and the derivation of bounds
on the amount of quantum information that can be jointly decoded by a group of
k receivers at the output of a symmetric broadcast channel.Comment: 19 pages, no figures, a new result added, published version to appear
  in Proceedings of TQC 201
Simple Sets of Measurements for Universal Quantum Computation and Graph
  State Preparation

We consider the problem of minimizing resources required for universal
quantum computation using only projective measurements. The resources we focus
on are observables, which describe projective measurements, and ancillary
qubits. We show that the set of observables {Z \otimes X, (cos\theta)X +
(sin\theta)Y all \theta \in [0, 2\pi)} with one ancillary qubit is universal
for quantum computation. The set is simpler than a previous one in the sense
that one-qubit projective measurements described by the observables in the set
are ones only in the (X,Y) plane of the Bloch sphere. The proof of the
universality immediately implies a simple set of observables that is
approximately universal for quantum computation. Moreover, the proof implies a
simple set of observables for preparing graph states efficiently.Comment: 10 pages, 7 figures, accepted to the fifth Conference on the Theory
  of Quantum Computation, Communication and Cryptography, 201
Simulating sparse Hamiltonians with star decompositions

We present an efficient algorithm for simulating the time evolution due to a
sparse Hamiltonian. In terms of the maximum degree d and dimension N of the
space on which the Hamiltonian H acts for time t, this algorithm uses
(d^2(d+log* N)||Ht||)^{1+o(1)} queries. This improves the complexity of the
sparse Hamiltonian simulation algorithm of Berry, Ahokas, Cleve, and Sanders,
which scales like (d^4(log* N)||Ht||)^{1+o(1)}. To achieve this, we decompose a
general sparse Hamiltonian into a small sum of Hamiltonians whose graphs of
non-zero entries have the property that every connected component is a star,
and efficiently simulate each of these pieces.Comment: 11 pages. v2: minor correction
Partially Ordered Two-way B\"uchi Automata

We introduce partially ordered two-way B\"uchi automata and characterize
their expressive power in terms of fragments of first-order logic FO[<].
Partially ordered two-way B\"uchi automata are B\"uchi automata which can
change the direction in which the input is processed with the constraint that
whenever a state is left, it is never re-entered again. Nondeterministic
partially ordered two-way B\"uchi automata coincide with the first-order
fragment Sigma2. Our main contribution is that deterministic partially ordered
two-way B\"uchi automata are expressively complete for the first-order fragment
Delta2. As an intermediate step, we show that deterministic partially ordered
two-way B\"uchi automata are effectively closed under Boolean operations.
  A small model property yields coNP-completeness of the emptiness problem and
the inclusion problem for deterministic partially ordered two-way B\"uchi
automata.Comment: The results of this paper were presented at CIAA 2010; University of
  Stuttgart, Computer Scienc
Optimal Hyper-Minimization

Minimal deterministic finite automata (DFAs) can be reduced further at the
expense of a finite number of errors. Recently, such minimization algorithms
have been improved to run in time O(n log n), where n is the number of states
of the input DFA, by [Gawrychowski and Je\.z: Hyper-minimisation made
efficient. Proc. MFCS, LNCS 5734, 2009] and [Holzer and Maletti: An n log n
algorithm for hyper-minimizing a (minimized) deterministic automaton. Theor.
Comput. Sci. 411, 2010]. Both algorithms return a DFA that is as small as
possible, while only committing a finite number of errors. These algorithms are
further improved to return a DFA that commits the least number of errors at the
expense of an increased (quadratic) run-time. This solves an open problem of
[Badr, Geffert, and Shipman: Hyper-minimizing minimized deterministic finite
state automata. RAIRO Theor. Inf. Appl. 43, 2009]. In addition, an experimental
study on random automata is performed and the effects of the existing
algorithms and the new algorithm are reported.Comment: 15 pages, 5 figure
A polynomial time match test for large classes of extended regular expressions

This is a conference paper. Further details of the conference can be found at: http://www.cs.umanitoba.ca/~ciaa2010/In the present paper, we study the match test for extended regular expressions. We approach this NP-complete problem by introducing a novel variant of two-way multihead automata, which reveals\ud
that the complexity of the match test is determined by a hidden combinatorial property of extended regular expressions, and it shows that\ud
a restriction of the corresponding parameter leads to rich classes with\ud
a polynomial time match test. For presentational reasons, we use the\ud
concept of pattern languages in order to specify extended regular expressions. While this decision, formally, slightly narrows the scope of our\ud
results, an extension of our concepts and results to more general notions\ud
of extended regular expressions is straightforward
Simulations of Weighted Tree Automata

Simulations of weighted tree automata (wta) are considered. It is shown how
such simulations can be decomposed into simpler functional and dual functional
simulations also called forward and backward simulations. In addition, it is
shown in several cases (fields, commutative rings, Noetherian semirings,
semiring of natural numbers) that all equivalent wta M and N can be joined by a
finite chain of simulations. More precisely, in all mentioned cases there
exists a single wta that simulates both M and N. Those results immediately
yield decidability of equivalence provided that the semiring is finitely (and
effectively) presented.Comment: 17 pages, 2 figure