18,768 research outputs found
On Evolutionary Algorithms for Multiple Criteria Decision Support in Bayesian Belief Networks Models of Dependable Software Development Processes.
On the heterogeneous character of water's amorphous polymorphism
In this letter we report {\it in situ} small--angle neutron scattering
results on the high--density (HDA) and low-density amorphous (LDA) ice
structures and on intermediate structures as found during the temperature
induced transformation of HDA into LDA. We show that the small--angle signal is
characterised by two regimes featuring different properties ( is the
modulus of the scattering vector defined as with being half the scattering
angle and the incident neutron wavelength). The very low--
regime ( \AA ) is dominated by a Porod--limit
scattering. Its intensity reduces in the course of the HDA to LDA
transformation following a kinetics reminiscent of that observed in wide--angle
diffraction experiments. The small--angle neutron scattering formfactor in the
intermediate regime of \AA HDA and LDA
features a rather flat plateau. However, the HDA signal shows an ascending
intensity towards smaller marking this amorphous structure as
heterogeneous. When following the HDA to LDA transition the formfactor shows a
pronounced transient excess in intensity marking all intermediate structures as
strongly heterogeneous on a length scale of some nano--meters
Incident Analysis & Digital Forensics in SCADA and Industrial Control Systems
SCADA and industrial control systems have been traditionally isolated in physically protected environments. However, developments such as standardisation of data exchange protocols and increased use of IP, emerging wireless sensor networks and machine-to-machine communication mean that in the near future related threat vectors will require consideration too outside the scope of traditional SCADA security and incident response. In the light of the significance of SCADA for the resilience of critical infrastructures and the related targeted incidents against them (e.g. the development of stuxnet), cyber security and digital forensics emerge as priority areas. In this paper we focus on the latter, exploring the current capability of SCADA operators to analyse security incidents and develop situational awareness based on a robust digital evidence perspective. We look at the logging capabilities of a typical SCADA architecture and the analytical techniques and investigative tools that may help develop forensic readiness to the level of the current threat environment requirements. We also provide recommendations for data capture and retention
Ammonia adsorption and decomposition on a tungsten /211/ surface
Ammonia adsorption and decomposition on tungsten 211 surface studied by mass spectrometry, electron diffraction, and changes in work functio
First steps in the oxidation of a /110/ nickel surface
Initial steps in oxidation of nickel surface studied using low energy back-reflection electron diffractio
Electron beam chemistry produces high purity metals
Application of radiation chemistry for deposition of metals by irradiation of aqueous solutions with high energy electrons is presented. Design of reaction vessel for irradiation of solution is illustrated. Features of radiochemical technique and procedures followed are described
Species Abundance Patterns in Complex Evolutionary Dynamics
An analytic theory of species abundance patterns (SAPs) in biological
networks is presented. The theory is based on multispecies replicator dynamics
equivalent to the Lotka-Volterra equation, with diverse interspecies
interactions. Various SAPs observed in nature are derived from a single
parameter. The abundance distribution is formed like a widely observed
left-skewed lognormal distribution. As the model has a general form, the result
can be applied to similar patterns in other complex biological networks, e.g.
gene expression.Comment: 4 pages, 3 figures. Physical Review Letters, in pres
- …