Konstantin Andreev

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In this paper we consider the problem of (<i>k</i>, <i>&#965;</i>)-balanced graph partitioning - dividing the vertices of a graph into <i>k</i> almost equal size components (each of size less than <i>&#965;</i> &#8226; <i>n</i>&lt;over&gt;<i>k</i>) so that the capacity of edges between different components is minimized. This problem is a natural(More)
In this paper we present a polynomial time approximation algorithm for designing a multicast overlay network. The algorithm finds a solution that satisfies capacity and reliability constraints to within a constant factor of optimal, and cost to within alogarithmic factor. The class of networks that our algorithm applies to includes the one used by Akamai(More)
We consider the problem of simultaneous source location: selecting locations for sources in a capacitated graph such that a given set of demands can be satisfied simultaneously, with the goal of minimizing the number of locations chosen. For general directed and undirected graphs we give an <i>O</i>(log <i>D</i>)-approximation algorithm, where <i>D</i> is(More)
In this paper, we present a polynomial time approximation algorithm for constructing an overlay multicast network for streaming live media events over the Internet. The class of overlay networks constructed by our algorithm include networks used by Akamai Technologies to deliver live media events to a global audience with high fidelity. In particular, we(More)
Antimicrobial peptides or their synthetic mimics are a promising class of potential new antibiotics. Herein we assess the effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanism of antimicrobial α-peptide-β-peptoid chimeras. Langmuir monolayers composed of(More)
Small hydrophilic antibiotics traverse the outer membrane of Gram-negative bacteria through porin channels. Large lipophilic agents traverse the outer membrane through its bilayer, containing a majority of lipopolysaccharides in its outer leaflet. Genes controlled by the two-component regulatory system PhoPQ modify lipopolysaccharides. We isolate(More)
The peptidomimetic approach has emerged as a powerful tool for overcoming the inherent limitations of natural antimicrobial peptides, where the therapeutic potential can be improved by increasing the selectivity and bioavailability. Restraining the conformational flexibility of a molecule may reduce the entropy loss upon its binding to the membrane.(More)
A piecewise continuous map for modeling bursting and spiking behaviour of isolated neuron is proposed. The map was created from phenomenological viewpoint. The map demonstrates oscillations, which are qualitatively similar to oscillations generating by Rose–Hindmarsh model. The synchronization in small ensembles of the maps is investigated. It is considered(More)
Konstantin Andreev1 Charles Garrod2 Bru e Maggs2 Adam Meyerson2 July 11, 2003 CMU-CS-03-162 S hool of Computer S ien e Carnegie Mellon University Pittsburgh, PA 15213 Abstra t We onsider the problem of Simultaneous Sour e Lo ation { sele ting lo ations for sour es in a apa itated graph su h that a given set of demands an be satis ed. We give an exa t(More)
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