4,778 research outputs found
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A dubiety-determining based model for database cumulated anomaly intrusion
The concept of Cumulated Anomaly (CA), which describes a new type of database anomalies, is addressed. A
typical CA intrusion is that when a user who is authorized to modify data records under certain constraints deliberately
hides his/her intentions to change data beyond constraints in different operations and different transactions. It happens
when some appearing to be authorized and normal transactions lead to certain accumulated results out of given thresholds.
The existing intrusion techniques are unable to deal with CAs. This paper proposes a detection model,
Dubiety-Determining Model (DDM), for Cumulated Anomaly. This model is mainly based on statistical theories and fuzzy
set theories. It measures the dubiety degree, which is presented by a real number between 0 and 1, for each database
transaction, to show the likelihood of a transaction to be intrusive. The algorithms used in the DDM are introduced. A
DDM-based software architecture has been designed and implemented for monitoring database transactions. The
experimental results show that the DDM method is feasible and effective
Statistical and fuzzy approach for database security
A new type of database anomaly is described by
addressing the concept of Cumulated Anomaly in this
paper. Dubiety-Determining Model (DDM), which is a
detection model basing on statistical and fuzzy set
theories for Cumulated Anomaly, is proposed. DDM
can measure the dubiety degree of each database
transaction quantitatively. Software system
architecture to support the DDM for monitoring
database transactions is designed. We also
implemented the system and tested it. Our
experimental results show that the DDM method is
feasible and effective
Quantum phonon transport of molecular junctions amide-linked with carbon nanotubes: a first-principle study
Quantum phonon transport through benzene and alkane chains amide-linked with
single wall carbon nanotubes (SWCNTs) is studied within the level of density
functional theory. The force constant matrices are obtained from standard
quantum chemistry software. The phonon transmission and thermal conductance are
from the nonequilibrium Green's function and the mode-matching method. We find
that the ballistic thermal conductance is not sensitive to the compression or
stretching of the molecular junction. The terminating groups of the SWCNTs at
the cutting edges only influence the thermal conductance quantitatively. The
conductance of the benzene and alkane chains shows large difference. Analysis
of the transmission spectrum shows that (i) the low temperature thermal
conductance is mainly contributed by the SWCNT transverse acoustic modes, (ii)
the degenerate phonon modes show different transmission probability due to the
presence of molecular junction, (iii) the SWCNT twisting mode can hardly be
transmitted by the alkane chain. As a result, the ballistic thermal conductance
of alkane chains is larger than that of benzene chains below 38 K, while it is
smaller at higher temperature.Comment: 5 pages, 5 figure
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Automatic parsing of sports videos with grammars
Motivated by the analogies between languages and sports videos, we introduce a novel
approach for video parsing with grammars. It utilizes compiler techniques for integrating both semantic
annotation and syntactic analysis to generate a semantic index of events and a table of content for a given
sports video. The video sequence is first segmented and annotated by event detection with domain
knowledge. A grammar-based parser is then used to identify the structure of the video content.
Meanwhile, facilities for error handling are introduced which are particularly useful when the results of
automatic parsing need to be adjusted. As a case study, we have developed a system for video parsing in
the particular domain of TV diving programs. Experimental results indicate the proposed approach is
effectiv
Killing Spinors for the Bosonic String
We obtain the effective action for the bosonic string with arbitrary
Yang-Mills fields, up to the \alpha' order, in general dimensions. The form of
the action is determined by the requirement that the action admit well-defined
Killing spinor equations, whose projected integrability conditions give rise to
the full set of equations of motion. The success of the construction suggests
that the hidden "pseudo-supersymmetry" associated with the Killing spinor
equations may be a property of the bosonic string itself.Comment: 9 page
General Kerr-NUT-AdS Metrics in All Dimensions
The Kerr-AdS metric in dimension D has cohomogeneity [D/2]; the metric
components depend on the radial coordinate r and [D/2] latitude variables \mu_i
that are subject to the constraint \sum_i \mu_i^2=1. We find a coordinate
reparameterisation in which the \mu_i variables are replaced by [D/2]-1
unconstrained coordinates y_\alpha, and having the remarkable property that the
Kerr-AdS metric becomes diagonal in the coordinate differentials dy_\alpha. The
coordinates r and y_\alpha now appear in a very symmetrical way in the metric,
leading to an immediate generalisation in which we can introduce [D/2]-1 NUT
parameters. We find that (D-5)/2 are non-trivial in odd dimensions, whilst
(D-2)/2 are non-trivial in even dimensions. This gives the most general
Kerr-NUT-AdS metric in dimensions. We find that in all dimensions D\ge4
there exist discrete symmetries that involve inverting a rotation parameter
through the AdS radius. These symmetries imply that Kerr-NUT-AdS metrics with
over-rotating parameters are equivalent to under-rotating metrics. We also
consider the BPS limit of the Kerr-NUT-AdS metrics, and thereby obtain, in odd
dimensions and after Euclideanisation, new families of Einstein-Sasaki metrics.Comment: Latex, 24 pages, minor typos correcte
Pseudo-Killing Spinors, Pseudo-supersymmetric p-branes, Bubbling and Less-bubbling AdS Spaces
We consider Einstein gravity coupled to an n-form field strength in D
dimensions. Such a theory cannot be supersymmetrized in general, we
nevertheless propose a pseudo-Killing spinor equation and show that the AdS X
Sphere vacua have the maximum number of pseudo-Killing spinors, and hence are
fully pseudo-supersymmetric. We show that extremal p-branes and their
intersecting configurations preserve fractions of the pseudo-supersymmetry. We
study the integrability condition for general (D,n) and obtain the additional
constraints that are required so that the existence of the pseudo-Killing
spinors implies the Einstein equations of motion. We obtain new
pseudo-supersymmetric bubbling AdS_5 X S^5 spaces that are supported by a
non-self-dual 5-form. This demonstrates that non-supersymmegtric conformal
field theories may also have bubbling states of arbitrary droplets of free
fermions in the phase space. We also obtain an example of less-bubbling AdS
geometry in D=8, whose bubbling effects are severely restricted by the
additional constraint arising from the integrability condition.Comment: typos corrected, extra comments and references added, version
appeared in JHE
Cosmological solutions, p-branes and the Wheeler-DeWitt equation
The low energy effective actions which arise from string theory or M-theory
are considered in the cosmological context, where the graviton, dilaton and
antisymmetric tensor field strengths depend only on time. We show that previous
results can be extended to include cosmological solutions that are related to
the E_N Toda equations. The solutions of the Wheeler-DeWitt equation in
minisuperspace are obtained for some of the simpler cosmological models by
introducing intertwining operators that generate canonical transformations
which map the theories into free theories. We study the cosmological properties
of these solutions, and also briefly discuss generalised Brans-Dicke models in
our framework. The cosmological models are closely related to p-brane solitons,
which we discuss in the context of the E_N Toda equations. We give the explicit
solutions for extremal multi-charge (D-3)-branes in the truncated system
described by the D_4 =O(4,4) Toda equations.Comment: 11 pages (2-column), Revte
Lambda and Anti-Lambda Hypernuclei in Relativistic Mean-field Theory
Several aspects about -hypernuclei in the relativistic mean field
theory, including the effective -nucleon coupling strengths based on
the successful effective nucleon-nucleon interaction PK1, hypernuclear magnetic
moment and -hypernuclei, have been presented. The effect of tensor
coupling in -hypernuclei and the impurity effect of to
nuclear structure have been discussed in detail.Comment: 8 pages, 2 figures, Proceedings of the Sendai International Symposium
"Strangeness in Nuclear and Hadronic Systems SENDAI08
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