216,159 research outputs found
The group of causal automorphisms
The group of causal automorphisms on Minkowski space-time is given and its
structure is analyzed
The q-component static model : modeling social networks
We generalize the static model by assigning a q-component weight on each
vertex. We first choose a component among the q components at random
and a pair of vertices is linked with a color according to their weights
of the component as in the static model. A (1-f) fraction of the entire
edges is connected following this way. The remaining fraction f is added with
(q+1)-th color as in the static model but using the maximum weights among the q
components each individual has. This model is motivated by social networks. It
exhibits similar topological features to real social networks in that: (i) the
degree distribution has a highly skewed form, (ii) the diameter is as small as
and (iii) the assortativity coefficient r is as positive and large as those in
real social networks with r reaching a maximum around .Comment: 5 pages, 6 figure
Unsupervised two-class and multi-class support vector machines for abnormal traffic characterization
Although measurement-based real-time traffic classification has received considerable research attention, the timing constraints imposed by the high accuracy requirements and the learning phase of the algorithms employed still remain a challenge. In this paper we propose a measurement-based classification framework that exploits unsupervised learning to accurately categorise network anomalies to specific classes. We introduce the combinatorial use of two-class and multi-class unsupervised Support Vector Machines (SVM)s to first distinguish normal from anomalous traffic and to further classify the latter category to individual groups depending on the nature of the anomaly
A computer algorithm for performing interactive algebraic computation on the GE Image-100 system
A subroutine which performs specialized algebraic computations upon ocean color scanner multispectral data is presented. The computed results are displayed on a video display. The subroutine exists as a component of the aircraft sensor analysis package. The user specifies the parameters of the computations by directly interacting with the computer. A description of the conversational options is also given
The results of initial analysis of OSTA-1/Ocean Color Experiment (OCE) imagery
Ocean view images from the Ocean Color Experiment (OCE) were produced at three widely separated locations on the Earth. Digital computer enhancement and band ratioing techniques were applied to radiometrically corrected OCE spectral data to emphasize patterns of chlorophyll distribution and, in one shallow, clear water case, bottom topography. The chlorophyll pattern in the Yellow Sea between China and Korea was evident in a scene produced from Shuttle Orbit 24. The effects of the discharge from the Yangtze and other rivers were also observed. Two scenes from orbits 30 and 32 revealed the movement of patches of plankton in the Gulf of Cadiz. Geometrical corrections to these images permitted the existing ocean current velocities in the vicinity to be deduced. The variability in water depth over the Grand Bahama Bank was estimated by using the blue-green OCE channel. The very clear water conditions in the area caused bottom reflected sunlight to produce a sensor signal which was related inversely to the depth of the water
Relationships between chlorophyll density and ocean radiance as measured by U2/OCS: Algorithms, examples and comparison
An ocean atmosphere radiative transfer process computation method which is suitable for determining lower boundary ocean albedo and other radiation components from spectral measurements of upwelling radiance taken from a high altitude platform is described. The method was applied to a set of color scanner data taken from slope water of the South Atlantic Bight to determine the influence of cholorophyll-a pigments in the sea on the ratio of upwelling radiance to down welling irradiance as a function of wavelength. The resulting chlorophyll concentrations are compared with measurements made by ships stationed along the flight path
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