948 research outputs found
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Operational tips for improving intrusion detection system performance
The installation of a new intrusion detection system (IDS) is, of course, expected to improve site security. However, depending upon the way the system is used, it can, over time, actually degrade security. Proper use, control, and maintenance of the IDS is critical if site security is to be maintained. This paper discusses several operational issues that should be addressed in order to use an IDS effectively. Several anecdotes from the author`s experience are given to illustrate proper and improper use of an IDS. Improper operational use of an IDS can render it ineffective. Applying these tips can help keep the IDS operating at peak performance
Chemical, mineralogical and petrological characterization of Gyaza iron ore deposit, Katsina State, Nigeria
No Abstract
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An annunciator architecture for the year 2000
Exciting new safeguards and security technologies are on the horizon, and some are even on the shelves today. Self-testing sensors, smart sensors, and intelligent alarm analyzers are all designed to provide useful information to the operator. However, today`s current annunciator systems were not designed to accommodate these new technologies. New display technologies are also changing the look and feel of the annunciator of the future. Annunciator technology needs to ``catch up` to these other security technologies. This paper presents the concept for a new, object-oriented approach to annunciator architecture design. The new architecture could accommodate simple, switch-closure devices as well as information- rich sensors and intelligent analyzers. In addition the architecture could allow other leading-edge interfaces to be easily integrated into the annunciator system. These technologies will reduce operator workload and aid the operator in making informed security decisions. 3 refs., 2 figs
Middle Convolution and Harnad Duality
We interpret the additive middle convolution operation in terms of the Harnad
duality, and as an application, generalize the operation to have a
multi-parameter and act on irregular singular systems.Comment: 50 pages; v2: Submitted version once revised according to referees'
comment
RSPO1/beta-Catenin Signaling Pathway Regulates Oogonia Differentiation and Entry into Meiosis in the Mouse Fetal Ovary
RSPO1/beta-Catenin Signaling Pathway Regulates Oogonia Differentiation and Entry into Meiosis in the Mouse Fetal Ovary
Differentiation of germ cells into male gonocytes or female oocytes is a central event in sexual reproduction. Proliferation and differentiation of fetal germ cells depend on the sex of the embryo. In male mouse embryos, germ cell proliferation is regulated by the RNA helicase Mouse Vasa homolog gene and factors synthesized by the somatic Sertoli cells promote gonocyte differentiation. In the female, ovarian differentiation requires activation of the WNT/β-catenin signaling pathway in the somatic cells by the secreted protein RSPO1. Using mouse models, we now show that Rspo1 also activates the WNT/β-catenin signaling pathway in germ cells. In XX Rspo1(−/−) gonads, germ cell proliferation, expression of the early meiotic marker Stra8, and entry into meiosis are all impaired. In these gonads, impaired entry into meiosis and germ cell sex reversal occur prior to detectable Sertoli cell differentiation, suggesting that β-catenin signaling acts within the germ cells to promote oogonial differentiation and entry into meiosis. Our results demonstrate that RSPO1/β-catenin signaling is involved in meiosis in fetal germ cells and contributes to the cellular decision of germ cells to differentiate into oocyte or sperm
Conductivity of 2D many-component electron gas, partially-quantized by magnetic field
The 2D semimetal consisting of heavy holes and light electrons is studied.
The consideration is based on assumption that electrons are quantized by
magnetic field while holes remain classical. We assume also that the
interaction between components is weak and the conversion between components is
absent. The kinetic equation for holes colliding with quantized electrons is
utilized. It has been stated that the inter-component friction and
corresponding correction to the dissipative conductivity {\it do
not vanish at zero temperature} due to degeneracy of the Landau levels. This
correction arises when the Fermi level crosses the Landau level.
The limits of kinetic equation applicability were found. We also study the
situation of kinetic memory when particles repeatedly return to the points of
their meeting.Comment: 13 pages, 1 figur
Proton Radiative Capture at E_p = 150 MeV
This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440
Reproducing Kernels of Generalized Sobolev Spaces via a Green Function Approach with Distributional Operators
In this paper we introduce a generalized Sobolev space by defining a
semi-inner product formulated in terms of a vector distributional operator
consisting of finitely or countably many distributional operators
, which are defined on the dual space of the Schwartz space. The types of
operators we consider include not only differential operators, but also more
general distributional operators such as pseudo-differential operators. We
deduce that a certain appropriate full-space Green function with respect to
now becomes a conditionally positive
definite function. In order to support this claim we ensure that the
distributional adjoint operator of is
well-defined in the distributional sense. Under sufficient conditions, the
native space (reproducing-kernel Hilbert space) associated with the Green
function can be isometrically embedded into or even be isometrically
equivalent to a generalized Sobolev space. As an application, we take linear
combinations of translates of the Green function with possibly added polynomial
terms and construct a multivariate minimum-norm interpolant to data
values sampled from an unknown generalized Sobolev function at data sites
located in some set . We provide several examples, such
as Mat\'ern kernels or Gaussian kernels, that illustrate how many
reproducing-kernel Hilbert spaces of well-known reproducing kernels are
isometrically equivalent to a generalized Sobolev space. These examples further
illustrate how we can rescale the Sobolev spaces by the vector distributional
operator . Introducing the notion of scale as part of the
definition of a generalized Sobolev space may help us to choose the "best"
kernel function for kernel-based approximation methods.Comment: Update version of the publish at Num. Math. closed to Qi Ye's Ph.D.
thesis (\url{http://mypages.iit.edu/~qye3/PhdThesis-2012-AMS-QiYe-IIT.pdf}
Implementation of a medium-modified parton shower algorithm
We present a Monte Carlo implementation of medium-induced gluon radiation in
the final-state branching process. Medium effects are introduced through an
additive term in the splitting functions. We have implemented such modification
within PYTHIA. We show the medium effects on the hump-backed plateau, and the
transverse momentum and angular distributions with respect to the parent
parton. As expected, with increasing medium densities there is an increase
(decrease) of partons with small (large) momentum fraction, and angular
broadening is observed. The effects on the transverse-momentum distributions
are more involved, with an enhancement of low- and intermediate- partons
and a decrease at large , which is related to energy conservation, and to
the lack of momentum exchange with the medium in our approach.Comment: LaTeX, 6 pages, 2 eps figures; proceedings of the 3rd International
Conference on Hard and Electromagnetic Probes in High-Energy Nuclear
Collisions - Hard Probes 2008 (Illa de A Toxa, Spain, June 8th-14th 2008
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