Academic University

Saint Petersburg, Russia

Academic University

Saint Petersburg, Russia
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Huletski A.,Academic University | Kartashov D.,Academic University | Krinkin K.,Saint Petersburg State University
IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems | Year: 2017

TinySLAM [1] is one of the most simple SLAM methods but the original implementation [2] is based on the specific robot model and provided as the ad-hoc application. Its key feature is simplicity of implementation and configuration at cost of accuracy (as our tests shown). Some changes were made in the original algorithm in order to minimize an error of estimated trajectories. The introduced model of cell leads to an error decrease on almost all tested indoor sequences. The proposed dynamic probability estimator improves usage of coarse-grained maps when memory efficiency is more desirable than accuracy. Obtained quantitative measurements justify the changes made in tinySLAM in case the method is used in a relatively small environment. © 2016 IEEE.

Huletski A.,Academic University | Kartashov D.,Academic University
ACM International Conference Proceeding Series | Year: 2016

Most of the methods that try to solve the SLAM problem use a prediction-correction approach to estimate current robot pose and map and can be spitted into several groups depending on a set of sensors they use and details of their implementation (e.g. a type of map, feature usage, etc.). Methods that belong to the same group usually differ only by cost functions and ad-hoc optimizations. To the best of our knowledge, a framework that provides a common set of components in order to speed up SLAM research is not publicly available (frameworks and toolkits that simplify development of particular SLAM parts are not taken into account). The paper introduces a framework that is under development and provides a set of components that simplify creation of methods based on 2D laser scan processing. The description of tinySLAM and GMapping implementations atop of the framework is provided in order to justify its usability. © 2016 ACM.

Krinkin K.,Saint Petersburg Electrotechnical University Leti | Filatov A.,Saint Petersburg Electrotechnical University Leti | Huletski A.,Academic University | Kartashov D.,Academic University
Conference of Open Innovation Association, FRUCT | Year: 2017

SLAM (simultaneous localization and mapping) problem appears in robot algorithms when it is necessary to orient in an unknown environment without GPS or some other world communication system. Data for considered SLAM method is received from laser rangefinders and odometry sensors. Scan matching is a localization step of the SLAM problem and the main idea is to find an offset between two laser scans-sets of points that presents a perception of environment from one observed point. Three different scan matchers based on various approaches are compared to determine the most accurate one. © 2016 FRUCT.

Savenko I.G.,University of Iceland | Savenko I.G.,Academic University | Magnusson E.B.,University of Iceland | Shelykh I.A.,University of Iceland | Shelykh I.A.,University of Lima
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Using the Lindblad approach we develop a general formalism for theoretical description of a spatially inhomogeneous bosonic system with dissipation provided by the interaction of bosons with a phonon bath. We apply our results to model the dynamics of an interacting one-dimensional polariton system in real space and time, analyzing in detail the role of polariton-polariton and polariton-phonon interactions. © 2011 American Physical Society.

PubMed | National Research University of Information Technologies, Vrije Universiteit Brussel, Optique Nonlineaire Theorique, Academic University and 5 more.
Type: Journal Article | Journal: Physical review. E | Year: 2016

A turn on of a quantum dot (QD) semiconductor laser simultaneously operating at the ground state (GS) and excited state (ES) is investigated both experimentally and theoretically. We find experimentally that the slow passage through the two successive laser thresholds may lead to significant delays in the GS and ES turn ons. The difference between the turn-on times is measured as a function of the pump rate of change and reveals no clear power law. This has motivated a detailed analysis of rate equations appropriate for two-state lasing QD lasers. We find that the effective time of the GS turn on follows an ^{-1/2} power law provided that the rate of change is not too small. The effective time of the ES transition follows an ^{-1} power law, but its first order correction in ln() is numerically significant. The two turn ons result from different physical mechanisms. The delay of the GS transition strongly depends on the slow growth of the dot population, whereas the ES transition only depends on the time needed to leave a repellent steady state.

Kavokin K.V.,RAS Ioffe Physical - Technical Institute | Kaliteevski M.A.,Durham University | Abram R.A.,Durham University | Kavokin A.V.,University of Southampton | And 3 more authors.
Applied Physics Letters | Year: 2010

We show that planar semiconductor microcavities in the strong coupling regime can be used as sources of stimulated terahertz radiation. Emitted terahertz photons would have a frequency equal to the splitting of the cavity polariton modes. The optical transition between upper and lower polariton branches is allowed due to mixing of the upper polariton state with one of the excited exciton states and is stimulated in the polariton laser regime. © 2010 American Institute of Physics.

Nikolenko S.I.,Academic University | Korobeynikov A.I.,Saint Petersburg State University | Alekseyev M.A.,University of South Carolina
BMC Genomics | Year: 2013

Error correction of sequenced reads remains a difficult task, especially in single-cell sequencing projects with extremely non-uniform coverage. While existing error correction tools designed for standard (multi-cell) sequencing data usually come up short in single-cell sequencing projects, algorithms actually used for single-cell error correction have been so far very simplistic. We introduce several novel algorithms based on Hamming graphs and Bayesian subclustering in our new error correction tool BAYESHAMMER. While BAYESHAMMER was designed for single-cell sequencing, we demonstrate that it also improves on existing error correction tools for multi-cell sequencing data while working much faster on real-life datasets. We benchmark BAYESHAMMER on both k-mer counts and actual assembly results with the SPADES genome assembler. © 2013 Nikolenko et al.

Demenkov E.,Saint Petersburg State University | Kojevnikov A.,Steklov Institute of Mathematics at Saint Petersburg | Kulikov A.,Steklov Institute of Mathematics at Saint Petersburg | Yaroslavtsev G.,Academic University
Information Processing Letters | Year: 2010

In this note, we present improved upper bounds on the circuit complexity of symmetric Boolean functions. In particular, we describe circuits of size 4.5 n + o (n) for any symmetric function of n variables, as well as circuits of size 3n for MOD3 n function. © 2010 Elsevier B.V. All rights reserved.

Aganezov S.,George Washington University | Sitdykova N.,Academic University | Alekseyev M.A.,George Washington University
Computational Biology and Chemistry | Year: 2015

Advances in DNA sequencing technology over the past decade have increased the volume of raw sequenced genomic data available for further assembly and analysis. While there exist many algorithms for assembly of sequenced genomic material, they often experience difficulties in constructing complete genomic sequences. Instead, they produce long genomic subsequences (scaffolds), which then become a subject to scaffold assembly aimed at reconstruction of their order along genome chromosomes. The balance between reliability and cost for scaffold assembly is not there just yet, which inspires one to seek for new approaches to address this problem. We present a new method for scaffold assembly based on the analysis of gene orders and genome rearrangements in multiple related genomes (some or even all of which may be fragmented). Evaluation of the proposed method on artificially fragmented mammalian genomes demonstrates its high reliability. We also apply our method for incomplete anophelinae genomes, which expose high fragmentation, and further validate the assembly results with referenced-based scaffolding. While the two methods demonstrate consistent results, the proposed method is able to identify more assembly points than the reference-based scaffolding. © 2015 Elsevier Ltd. All rights reserved.

Savenko I.G.,University of Iceland | Savenko I.G.,Academic University | Shelykh I.A.,University of Iceland | Shelykh I.A.,International Institute of Physics | Kaliteevski M.A.,RAS Ioffe Physical - Technical Institute
Physical Review Letters | Year: 2011

We consider the nonlinear terahertz emission by the system of cavity polaritons in the regime of polariton lasing. To account for the quantum nature of terahertz-polariton coupling, we use the Lindblad master equation approach and demonstrate that quantum microcavities reveal a rich variety of nonlinear phenomena in the terahertz range, including bistability, short terahertz pulse generation, and terahertz switching. © 2011 American Physical Society.

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