67,707 research outputs found
On a Conjecture of Givental
These brief notes record our puzzles and findings surrounding Givental's
recent conjecture which expresses higher genus Gromov-Witten invariants in
terms of the genus-0 data. We limit our considerations to the case of a
projective line, whose Gromov-Witten invariants are well-known and easy to
compute. We make some simple checks supporting his conjecture.Comment: 13 pages, no figures; v.2: new title, minor change
Polygraph: Automatically generating signatures for polymorphic worms
It is widely believed that content-signature-based intrusion detection systems (IDSes) are easily evaded by polymorphic worms, which vary their payload on every infection attempt. In this paper, we present Polygraph, a signature generation system that successfully produces signatures that match polymorphic worms. Polygraph generates signatures that consist of multiple disjoint content sub-strings. In doing so, Polygraph leverages our insight that for a real-world exploit to function properly, multiple invariant substrings must often be present in all variants of a payload; these substrings typically correspond to protocol framing, return addresses, and in some cases, poorly obfuscated code. We contribute a definition of the polymorphic signature generation problem; propose classes of signature suited for matching polymorphic worm payloads; and present algorithms for automatic generation of signatures in these classes. Our evaluation of these algorithms on a range of polymorphic worms demonstrates that Polygraph produces signatures for polymorphic worms that exhibit low false negatives and false positives. © 2005 IEEE
U-health expert system with statistical neural network
Ubiquitous Health(U-Health) system witch focuses on automated applications that can provide healthcare to human anywhere and anytime using wired and wireless mobile technologies is becoming increasingly important. This system consists of a network system to collect data and a sensor module which measures pulse, blood pressure, diabetes, blood sugar, body fat diet with management and measurement of stress etc, by both wired and wireless and further portable mobile connections. In this paper, we propose an expert system using back-propagation to support the diagnosis of citizens in U-Health system
Energetics and kinetics of Li intercalation in irradiated graphene scaffolds
In the present study we investigate the irradiation-defects hybridized
graphene scaffold as one potential building material for the anode of Li-ion
batteries. Designating the Wigner V22 defect as a representative, we illustrate
the interplay of Li atoms with the irradiation-defects in graphene scaffolds.
We examine the adsorption energetics and diffusion kinetics of Li in the
vicinity of a Wigner V22 defect using density functional theory calculations.
The equilibrium Li adsorption sites at the defect are identified and shown to
be energetically preferable to the adsorption sites on pristine (bilayer)
graphene. Meanwhile the minimum energy paths and corresponding energy barriers
for Li migration at the defect are determined and computed. We find that while
the defect is shown to exhibit certain trapping effects on Li motions on the
graphene surface, it appears to facilitate the interlayer Li diffusion and
enhance the charge capacity within its vicinity because of the reduced
interlayer spacing and characteristic symmetry associated with the defect. Our
results provide critical assessment for the application of irradiated graphene
scaffolds in Li-ion batteries.Comment: 23 pages, 5 figure
On the predominant mechanisms active during the high power diode laser modification of the wettability characteristics of an SiO2/Al2O3-based ceramic material
The mechanisms responsible for modifications to the wettability characteristics of a SiO2/Al2O3-based ceramic material in terms of a test liquid set comprising of human blood, human blood plasma, glycerol and 4-octonol after high power diode laser (HPDL) treatment have been elucidated. Changes in the contact angle, , and hence the wettability characteristics of the SiO2/Al2O3-based ceramic were attributed primarily to: modifications to the surface roughness of the ceramic resulting from HPDL interaction which accordingly effected reductions in ; the increase in the surface O2 content of the ceramic after HPDL treatment; since an increase in surface O2 content intrinsically brings about a decrease in , and vice versa and the increase in the polar component of the surface energy, due to the HPDL induced surface melting and resolidification which consequently created a partially vitrified microstructure that was seen to augment the wetting action. However, the degree of influence exerted by each mechanism was found to differ markedly. Isolation of each of these mechanisms permitted the magnitude of their influence to be qualitatively determined. Surface energy, by way of microstructural changes, was found to be by far the most predominant element governing the wetting characteristics of the SiO2/Al2O3-based ceramic. To a much lesser extent, surface O2 content, by way of process gas, was also seen to influence to a changes in the wettability characteristics of the SiO2/Al2O3-based ceramic, whilst surface roughness was found to play a minor role in inducing changes in the wettability characteristics
Coherent States and Geometric Phases in Calogero-Sutherland Model
Exact coherent states in the Calogero-Sutherland models (of time-dependent
parameters) which describe identical harmonic oscillators interacting through
inverse-square potentials are constructed, in terms of the classical solutions
of a harmonic oscillator. For quasi-periodic coherent states of the
time-periodic systems, geometric phases are evaluated. For the
Calogero-Sutherland model, the phase is calculated for a general coherent
state. The phases for other models are also considered.Comment: To appear in the Int. J. Mod. Phys.
VISHNU hybrid model for viscous QCD matter at RHIC and LHC energies
In this proceeding, we briefly describe the viscous hydrodynamics + hadron
cascade hybrid model VISHNU for relativistic heavy ion collisions and report
the current status on extracting the QGP viscosity from elliptic flow data.Comment: 4 pages, 1 figure, the proceedings of 7th International Workshop on
Critical Point and Onset of Deconfinement, Wuhan, China, Nov. 7-11, 201
Generalization of the Darboux transformation and generalized harmonic oscillators
The Darbroux transformation is generalized for time-dependent Hamiltonian
systems which include a term linear in momentum and a time-dependent mass. The
formalism for the -fold application of the transformation is also
established, and these formalisms are applied for a general quadratic system (a
generalized harmonic oscillator) and a quadratic system with an inverse-square
interaction up to N=2. Among the new features found, it is shown, for the
general quadratic system, that the shape of potential difference between the
original system and the transformed system could oscillate according to a
classical solution, which is related to the existence of coherent states in the
system
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