Botnets represent a global problem and are responsible for causing large financial and operational damage to their victims. They are implemented with evasion in mind, and aim at hiding their architecture and authors, making them difficult to detect in general. These kinds of networks are mainly used for identity theft, virtual extortion, spam campaigns and malware dissemination. Botnets have a great potential in warfare and terrorist activities, making it of utmost importance to take action against. We present CONDENSER, a method for identifying data generated by botnet activity. We start by selecting appropriate the features from several data feeds, namely DNS non-existent domain responses and live communication packages directed to command and control servers that we previously sinkholed. By using machine learning algorithms and a graph based representation of data, then allows one to identify botnet activity, helps identifying anomalous traffic, quickly detect new botnets and improve activities of tracking known botnets. Our main contributions are threefold: first, the use of a machine learning classifier for classifying domain names as being generated by domain generation algorithms (DGA); second, a clustering algorithm using the set of selected features that groups network communication with similar patterns; third, a graph based knowledge representation framework where we store processed data, allowing us to perform queries.
The Davies-Bouldin @cite_7 index -- represented as @math -- identifies that are compact and distant from each other, in Equation the diameter for @math is obtained, where @math represents the number of points belonging to @math . Symbol @math corresponds to the centroid of @math and @math is a point belonging to @math .
@cite_7
2005598280 2001085501 2094048240 2338231399
We derive a new upper bound on the diameter of a polyhedron @math P = x ? R n : A x ≤ b , where @math A ? Z m × n . The bound is polynomial in @math n and the largest absolute value of a sub-determinant of @math A , denoted by @math Δ . More precisely, we show that the diameter of @math P is bounded by @math O ( Δ 2 n 4 log n Δ ) . If @math P is bounded, then we show that the diameter of @math P is at most @math O ( Δ 2 n 3.5 log n Δ ) . For the special case in which @math A is a totally unimodular matrix, the bounds are @math O ( n 4 log n ) and @math O ( n 3.5 log n ) respectively. This improves over the previous best bound of @math O ( m 16 n 3 ( log m n ) 3 ) due to Dyer and Frieze (Math Program 64:1---16, 1994). Given a set of @math points in @math , how many dimensions are needed to represent all pair wise distances within a specific distortion? This dimension-distortion tradeoff question is well understood for the @math norm, where @math dimensions suffice to achieve @math distortion. In sharp contrast, there is a significant gap between upper and lower bounds for dimension reduction in @math . A recent result shows that distortion @math can be achieved with @math dimensions. On the other hand, the only lower bounds known are that distortion @math requires @math dimensions and that distortion @math requires @math dimensions. In this work, we show the first near linear lower bounds for dimension reduction in @math . In particular, we show that @math distortion requires at least @math dimensions. Our proofs are combinatorial, but inspired by linear programming. In fact, our techniques lead to a simple combinatorial argument that is equivalent to the LP based proof of Brinkman-Charikar for lower bounds on dimension reduction in @math . We present new approximation algorithms for the @math -median and @math -means clustering problems. To this end, we obtain small coresets for @math -median and @math -means clustering in general metric spaces and in Euclidean spaces. In @math , these coresets are of size with polynomial dependency on the dimension @math . This leads to @math -approximation algorithms to the optimal @math -median and @math -means clustering in @math , with running time @math , where @math is the number of points. This improves over previous results. We use those coresets to maintain a @math -approximate @math -median and @math -means clustering of a stream of points in @math , using @math space. These are the first streaming algorithms, for those problems, that have space complexity with polynomial dependency on the dimension. Let @math denote the maximum diameter of a @math -dimensional polyhedron with @math facets. In this paper, we propose a unified analysis of a recursive inequality about @math established by Kalai and Kleitman in 1992. This yields much simpler proofs of a tail--polynomial and tail--almost--linear bounds on @math which are recently discussed by Gallagher and Kim.