Lightweight Internet Traffic Classification - A Subject Based Solution with Word Embeddings

Internet traffic classification is a relevant and mature research field, anyway of growing importance and with still open technical challenges, also due to the pervasive presence of Internet-connected devices into everyday life. We claim the need for innovative traffic classification solutions capable of being lightweight, of adopting a domain-based approach, of not only concentrating on application-level protocol categorization but also classifying Internet traffic by subject. To this purpose, this paper originally proposes a classification solution that leverages domain name information extracted from IPFIX summaries, DNS logs, and DHCP leases, with the possibility to be applied to any kind of traffic. Our proposed solution is based on an extension of Word2vec unsupervised learning techniques running on a specialized Apache Spark cluster. In particular, learning techniques are leveraged to generate word-embeddings from a mixed dataset composed by domain names and natural language corpuses in a lightweight way and with general applicability. The paper also reports lessons learnt from our implementation and deployment experience that demonstrates that our solution can process 5500 IPFIX summaries per second on an Apache Spark cluster with 1 slave instance in Amazon EC2 at a cost of $ 3860 year. Reported experimental results about Precision, Recall, F-Measure, Accuracy, and Cohen's Kappa show the feasibility and effectiveness of the proposal. The experiments prove that words contained in domain names do have a relation with the kind of traffic directed towards them, therefore using specifically trained word embeddings we are able to classify them in customizable categories. We also show that training word embeddings on larger natural language corpuses leads improvements in terms of precision up to 180%.

On the initiation of boudinage and folding instabilities in layered elasto-visco-plastic solids - Insights from natural microstructures and numerical simulations

The present understanding of the initiation of boudinage and folding structures is based on viscosity contrasts and stress exponents, considering an intrinsically unstable state of the layer. The criterion of localization is believed to be prescribed by geometry-material interactions, which are often encountered in natural structures. An alternative localization phenomenon has been established for ductile materials, in which instability emerges for critical material parameters and loading rates from homogeneous conditions. In this thesis, conditions are sought under which this type of instability prevails and whether localization in geological materials necessarily requires a trigger by geometric imperfections. The relevance of critical deformation conditions, material parameters and the spatial configuration of instabilities are discussed in a geological context. In order to analyze boudinage geometries, a numerical eigenmode analysis is introduced. This method allows determining natural frequencies and wavelengths of a structure and inducing perturbations on these frequencies. In the subsequent coupled thermo-mechanical simulations, using a grain size evolution and end-member flow laws, localization emerges when material softening through grain size sensitive viscous creep sets in. Pinch-and-swell structures evolve along slip lines through a positive feedback between the matrix response and material bifurcations inside the layer, independent from the mesh-discretization length scale. Since boudinage and folding are considered to express the same general instability, both structures should arise independently of the sign of the loading conditions and for identical material parameters. To this end, the link between material to energy instabilities is approached by means of bifurcation analyses of the field equations and finite element simulations of the coupled system of equations. Boudinage and folding structures develop at the same critical energy threshold, where dissipative work by temperature-sensitive creep overcomes the diffusive capacity of the layer. This finding provides basis for a unified theory for strain localization in layered ductile materials. The numerical simulations are compared to natural pinch-and-swell microstructures, tracing the adaption of grain sizes, textures and creep mechanisms in calcite veins. The switch from dislocation to diffusion creep relates to strain-rate weakening, which is induced by dissipated heat from grain size reduction, and marks the onset of continuous necking. The time-dependent sequence uncovers multiple steady states at different time intervals. Microstructurally and mechanically stable conditions are finally expressed in the pinch-and-swell end members. The major outcome of this study is that boudinage and folding can be described as the same coupled energy-mechanical bifurcation, or as one critical energy attractor. This finding allows the derivation of critical deformation conditions and fundamental material parameters directly from localized structures in the field.

Alteration of natural ³⁷Ar activity concentration in the subsurface by gas transport and water infiltration

High ³⁷Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of ³⁷Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict ³⁷Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating ³⁷Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for ³⁷Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural ³⁷Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of ³⁷Ar activity concentrations. The influence of soil water content on ³⁷Ar production is shown to be negligible to first order, while ³⁷Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI.

History of the expedition under the command of Captains Lewis and Clarke, to the sources of the Missouri ... : performed during the years 1804, 1805, 1806, by order of the government of the United States /

The chapter on natural history (1st edition, v. 2, chapter 7) is in this edition transferred to the appendix. In this appendix the Estimate of the western Indians is given under the heading: "Enumeration of Indian nations and their places of general residence."

Natural history of the Adelie penguin.

Mode of access: Internet.

The history of the collections contained in the Natural history departments of the British museum.

I. Libraries. The Department of botany. The Department of Geology. The Department of minerals. 1904.--II. Separate historical accounts of the several collections included in the Department of zoology. 1906.--II. Appendix. General history of the Department of zoology from 1856 to 1895, by Dr. Albert Günther. 1912.

Techniques to measure damages to natural resources : final report /

"June 1987."

Voyage de decouvertes de l'Astrolabe exécutée par order du roi pendant les années 1826-1827-1828-1829, sous le commandement de M. J. Dumont d'Urville.

Mode of access: Internet.

Guide to the specimens illustrating the races of mankind (anthropology) exhibited in the Department of zoology, British museum (Natural history) ...

Compiled by R. Lydekker.

Catalogue of the ungulate mammals in the British Museum (Natural History)

Mode of access: Internet.

Catalogue of meteorites : with special reference to those represented in the collection of the British Museum (natural history)

Accompanied by "Second Appendix ... by Max H. Hey." (136 p. 22 cm.) Published: London, Printed by order of the Trustees of the British Museum, 1940.

Thoughts on the moral order of nature /

Mode of access: Internet.

History of the expedition under the command of Captains Lewis and Clarke, to the sources of the Missouri : thence across the Rockey Mountains, and down the river Columbia to the Pacific Ocean ; performed during the years 1804, 1805, 1806, by order of the government of the United States /

The chapter on natural history (1st edition, v. 2, chapter 7) is in this edition transferred to the appendix. In this appendix the Estimate of the western Indians is given under the heading: "Enumeration of Indian nations and their places of general residence".

Travels in Iceland: performed by order of his Danish majesty.

I̲ṉ Phillips, R., pub. Collection of modern and contemporary voyages and travels. 1805-10. 22 cm. v.2

Memoirs of the American Museum of Natural History.

Editor: v. 1, J.A. Allen; v. 2, 1808-1900, Franz Boas.