892 research outputs found
State-of-the-art oriented review of CIRCUS
Mathematical procedures for CIRCUS, digital computer program which is based on built-in model library and is capable of time domain analysis of certain circuit
The correction of hadronic nucleus polarizability to hyperfine structure of light muonic atoms
The calculation of hadronic polarizability contribution of the nucleus to
hyperfine structure of muonic hydrogen and helium is carried out within the
unitary isobar model and experimental data on the polarized structure functions
of deep inelastic lepton-proton and lepton-deuteron scattering. The calculation
of virtual absorption cross sections of transversely and longitudinally
polarized photons by nucleons in the resonance region is performed in the
framework of the program MAID.Comment: 8 pages, 3 figures, Talk presented at 23th International Workshop on
High Energy Physics and Quantum Field Theory (QFTHEP 2017
Triangulations and volume form on moduli spaces of flat surfaces
In this paper, we are interested in flat metric structures with conical
singularities on surfaces which are obtained by deforming translation surface
structures. The moduli space of such flat metric structures can be viewed as
some deformation of the moduli space of translation surfaces. Using geodesic
triangulations, we define a volume form on this moduli space, and show that, in
the well-known cases, this volume form agrees with usual ones, up to a
multiplicative constant.Comment: 42 page
Spherical averages in the space of marked lattices
A marked lattice is a -dimensional Euclidean lattice, where each lattice
point is assigned a mark via a given random field on . We prove
that, if the field is strongly mixing with a faster-than-logarithmic rate, then
for every given lattice and almost every marking, large spheres become
equidistributed in the space of marked lattices. A key aspect of our study is
that the space of marked lattices is not a homogeneous space, but rather a
non-trivial fiber bundle over such a space. As an application, we prove that
the free path length in a crystal with random defects has a limiting
distribution in the Boltzmann-Grad limit
Formation of hot tear under controlled solidification conditions
Aluminum alloy 7050 is known for its superior mechanical properties, and thus finds its application in aerospace industry. Vertical direct-chill (DC) casting process is typically employed for producing such an alloy. Despite its advantages, AA7050 is considered as a "hard-to-cast" alloy because of its propensity to cold cracking. This type of cracks occurs catastrophically and is difficult to predict. Previous research suggested that such a crack could be initiated by undeveloped hot tears (microscopic hot tear) formed during the DC casting process if they reach a certain critical size. However, validation of such a hypothesis has not been done yet. Therefore, a method to produce a hot tear with a controlled size is needed as part of the verification studies. In the current study, we demonstrate a method that has a potential to control the size of the created hot tear in a small-scale solidification process. We found that by changing two variables, cooling rate and displacement compensation rate, the size of the hot tear during solidification can be modified in a controlled way. An X-ray microtomography characterization technique is utilized to quantify the created hot tear. We suggest that feeding and strain rate during DC casting are more important compared with the exerted force on the sample for the formation of a hot tear. In addition, we show that there are four different domains of hot-tear development in the explored experimental window-compression, microscopic hot tear, macroscopic hot tear, and failure. The samples produced in the current study will be used for subsequent experiments that simulate cold-cracking conditions to confirm the earlier proposed model.This research was carried out within the Materials innovation institute (www.m2i.nl) research framework, project no. M42.5.09340
Sum of Lyapunov exponents of the Hodge bundle with respect to the Teichmuller geodesic flow
We compute the sum of the positive Lyapunov exponents of the Hodge bundle
with respect to the Teichmuller geodesic flow. The computation is based on the
analytic Riemann-Roch Theorem and uses a comparison of determinants of flat and
hyperbolic Laplacians when the underlying Riemann surface degenerates.Comment: Minor corrections. To appear in Publications mathematiques de l'IHE
Comparison of System Call Representations for Intrusion Detection
Over the years, artificial neural networks have been applied successfully in
many areas including IT security. Yet, neural networks can only process
continuous input data. This is particularly challenging for security-related
non-continuous data like system calls. This work focuses on four different
options to preprocess sequences of system calls so that they can be processed
by neural networks. These input options are based on one-hot encoding and
learning word2vec or GloVe representations of system calls. As an additional
option, we analyze if the mapping of system calls to their respective kernel
modules is an adequate generalization step for (a) replacing system calls or
(b) enhancing system call data with additional information regarding their
context. However, when performing such preprocessing steps it is important to
ensure that no relevant information is lost during the process. The overall
objective of system call based intrusion detection is to categorize sequences
of system calls as benign or malicious behavior. Therefore, this scenario is
used to evaluate the different input options as a classification task. The
results show, that each of the four different methods is a valid option when
preprocessing input data, but the use of kernel modules only is not recommended
because too much information is being lost during the mapping process.Comment: 12 pages, 1 figure, submitted to CISIS 201
A Behavior-Based Approach To Securing Email Systems
The Malicious Email Tracking (MET) system, reported in a prior publication, is a behavior-based security system for email services. The Email Mining Toolkit (EMT) presented in this paper is an offline email archive data mining analysis system that is designed to assist computing models of malicious email behavior for deployment in an online MET system. EMT includes a variety of behavior models for email attachments, user accounts and groups of accounts. Each model computed is used to detect anomalous and errant email behaviors. We report on the set of features implemented in the current version of EMT, and describe tests of the system and our plans for extensions to the set of models
The genetic basis of host preference and resting behavior in the major African malaria vector, Anopheles arabiensis
Malaria transmission is dependent on the propensity of Anopheles mosquitoes to bite
humans (anthropophily) instead of other dead end hosts. Recent increases in the usage of
Long Lasting Insecticide Treated Nets (LLINs) in Africa have been associated with reductions in highly anthropophilic and endophilic vectors such as Anopheles gambiae s.s., leaving species with a broader host range, such as Anopheles arabiensis, as the most
prominent remaining source of transmission in many settings. An. arabiensis appears to be
more of a generalist in terms of its host choice and resting behavior, which may be due to
phenotypic plasticity and/or segregating allelic variation. To investigate the genetic basis of host choice and resting behavior in An. arabiensis we sequenced the genomes of 23
human-fed and 25 cattle-fed mosquitoes collected both in-doors and out-doors in the Kilombero Valley, Tanzania. We identified a total of 4,820,851 SNPs, which were used to conduct the first genome-wide estimates of “SNP heritability”for host choice and resting
behavior in this species. A genetic component was detected for host choice (human vs cow
fed; permuted P = 0.002), but there was no evidence of a genetic component for resting
behavior (indoors versus outside; permuted P = 0.465). A principal component analysis
(PCA) segregated individuals based on genomic variation into three groups which were
characterized by differences at the 2Rb and/or 3Ra paracentromeric chromosome inversions. There was a non-random distribution of cattle-fed mosquitoes between the PCA clusters, suggesting that alleles linked to the 2Rb and/or 3Ra inversions may influence host
choice. Using a novel inversion genotyping assay, we detected a significant enrichment of
the standard arrangement (non-inverted) of 3Ra among cattle-fed mosquitoes (N = 129)
versus all non-cattle-fed individuals. Thus, tracking the frequency of the 3Ra in An. arabiensis populations may be of use to infer selection on host choice behavior within these vector populations; possibly in response to vector control. Controlled
host-choice assays are needed to discern whether the observed genetic component has a
direct relationship with innate host preference. A better understanding of the genetic basis
for host feeding behavior in An. arabiensis may also open avenues for novel vector control
strategies based on driving genes for zoophily into wild mosquito populations
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