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2. On the Easy Use of Scientific Computing Services for Large Scale Linear Algebra and Parallel Decision Making with the P-Grade Portal

Author

Ronan Guivarch, Michel Daydé, Hrachya Astsatryan, Harutyun Terzyan, Levon Hovhannisyan, Yuri Shoukouryan, Vladimir Sahakyan, Aurélie Hurault, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), National Academy of Sciences of the Republic of Armenia (ARMENIA), State Engineering University of Armenia - SEUA (ARMENIA), Institute for Informatics and Automation Problems, NAS of Armenia, Algorithmes Parallèles et Optimisation (IRIT-APO), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Institut National Polytechnique (Toulouse) (Toulouse INP), Assistance à la Certification d’Applications DIstribuées et Embarquées (IRIT-ACADIE), Institut de recherche en informatique de Toulouse ( IRIT ), Institut National Polytechnique [Toulouse] ( INP ) -Université Toulouse 1 Capitole ( UT1 ) -Université Toulouse 2 ( UT2 ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National de la Recherche Scientifique ( CNRS ), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UPS (FRANCE), Institute for Informatics and Automation Problems - IIAP (Yerevan, Armenie), and Institut de Recherche en Informatique de Toulouse - IRIT (Toulouse, France)

Subjects
Computer Networks and Communications, Iterative method, Computer science, Interface (computing), Distributed computing, Parallel Decision Making, Cloud computing, 010103 numerical & computational mathematics, 02 engineering and technology, computer.software_genre, 01 natural sciences, Computational science, [ INFO.INFO-DC ] Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], 0202 electrical engineering, electronic engineering, information engineering, 0101 mathematics, Advanced Trading, Block (data storage), Sparse Linear Algebra Solvers, business.industry, P-grade Portal, Grid, Calcul parallèle, distribué et partagé, Grid computing, Hardware and Architecture, Linear algebra, 020201 artificial intelligence & image processing, Single sign-on, [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, computer, Software, Information Systems
Abstract

International audience; Scientific research is becoming increasingly dependent on the large-scale analysis of data using distributed computing infrastructures (Grid, cloud, GPU, etc.). Scientific computing (Petitet et al. 1999) aims at constructing mathematical models and numerical solution techniques for solving problems arising in science and engineering. In this paper, we describe the services of an integrated portal based on the P-Grade (Parallel Grid Run-time and Application Development Environment) portal (http://www.p-grade.hu) that enables the solution of large-scale linear systems of equations using direct solvers, makes easier the use of parallel block iterative algorithm and provides an interface for parallel decision making algorithms. The ultimate goal is to develop a single sign on integrated multi-service environment providing an easy access to different kind of mathematical calculations and algorithms to be performed on hybrid distributed computing infrastructures combining the benefits of large clusters, Grid or cloud, when needed.

Published
2013

4. f-Divergence Measures for Evaluation in Community Detection

Author

Haroutunian, Mariam, Mkhitaryan, Karen, Mothe, Josiane, Institute for Informatics and Automation Problems, NAS of Armenia, Systèmes d’Informations Généralisées (IRIT-SIG), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse - Jean Jaurès (UT2J), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), National Academy of Sciences of the Republic of Armenia (ARMENIA), and Institut National Polytechnique de Toulouse - INPT (FRANCE)

Subjects
Théorie de l'information, Information theory, Community detection, [INFO.INFO-IT]Computer Science [cs]/Information Theory [cs.IT], f-divergence distance measures
Abstract

International audience; Community detection is a research area from network science dealing with the investigation of complex networks such as biological, social and computer networks, aiming to identify subgroups (communities) of entities (nodes) that are more closely related to each other than with remaining entities in the network [1]. Various community detection algorithms are used in the literature however the evaluation of their derived community structure is a challenging task due to varying results on different networks. In searching good community detection algorithms diverse comparison measures are used actively [2]. Information theoretic measures form a fundamental class in this discipline and have recently received increasing interest [3]. In this paper we first mention the usual evaluation measures used for community detection evaluation We then review the properties of f -divergence measures and propose the ones that can serve community detection evaluation. Preliminary experiments show the advantage of these measures in the case of large number of communities.

Published
2018

5. Working set size estimation techniques in virtualized environments: One size does not fit all

Author

AstsatryanHrachya, HagimontDaniel, NituVlad, KocharyanAram, TchanaAlain, YayaHannas, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), National Academy of Sciences of the Republic of Armenia (ARMENIA), and Institute for Informatics and Automation Problems - IIAP (Yerevan, Armenie)

Subjects
Software_OPERATINGSYSTEMS, Computer Networks and Communications, Computer science, Distributed computing, Système d'exploitation, Réseaux et télécommunications, Cloud computing, 02 engineering and technology, computer.software_genre, Architectures Matérielles, Virtualization, 0202 electrical engineering, electronic engineering, information engineering, Computer Science (miscellaneous), Resource management, Safety, Risk, Reliability and Quality, Energy consumption optimization, business.industry, Working set size, 020207 software engineering, Energy consumption, Systèmes embarqués, 020202 computer hardware & architecture, Hardware and Architecture, Virtual machine, business, computer
Abstract

Energy consumption is a primary concern for datacenters? management. Numerous datacenters are relying on virtualization, as it provides flexible resource management means such as virtual machine (VM) checkpoint/restart, migration and consolidation. However, one of the main hindrances to server consolidation is physical memory. In nowadays cloud, memory is generally statically allocated to VMs and wasted if not used. Techniques (such as ballooning) were introduced for dynamically reclaiming memory from VMs, such that only the needed memory is provisioned to each VM. However, the challenge is to precisely monitor the needed memory, i.e., the working set of each VM. In this paper, we thoroughly review the main techniques that were proposed for monitoring the working set of VMs. Additionally, we have implemented the main techniques in the Xen hypervisor and we have defined different metrics in order to evaluate their efficiency. Based on the evaluation results, we propose Badis, a system which combines several of the existing solutions, using the right solution at the right time. We also propose a consolidation extension which leverages Badis in order to pack the VMs based on the working set size and not the booked memory. The implementation of all techniques, our proposed system, and the benchmarks we have used are publicly available in order to support further research in this domain.

Published
2018

6. Weather Data Visualization and Analytical Platform

Author

Hrachya Astsatryan, Julien Aligon, Rita Abrahamyan, Anush Hakobyan, Hayk Grogoryan, Zarmandukht Petrosyan, Wahi Narsisian, Vladimir Sahakyan, Eliza Gyulgyulyan, Aram Kocharyan, Yuri Shoukourian, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), National Academy of Sciences of the Republic of Armenia (ARMENIA), Armstatehydromet (ARMENIA), Institut de Recherche en Informatique de Toulouse - IRIT (Toulouse, France), Université Toulouse III - Paul Sabatier - UPS (FRANCE), Institute for Informatics and Automation Problems - IIAP (Yerevan, Armenie), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)

Subjects
Service (systems architecture), Web-based visualization, Observational data, 010504 meteorology & atmospheric sciences, General Computer Science, Computer science, Numerical weather prediction, 02 engineering and technology, 01 natural sciences, Satellite image processing, 0202 electrical engineering, electronic engineering, information engineering, Hydrometeorology, Relative humidity, Interactive visualization, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Remote sensing, OLAP, Online analytical processing, Visualization, Weather data, 13. Climate action, Base de données, 020201 artificial intelligence & image processing
Abstract

This article aims to present a web-based interactive visualization and analytical platform for weather data in Armenia by integrating the three existing infrastructures for observational data, numerical weather prediction, and satellite image processing. The weather data used in the platform consists of near-surface atmospheric elements including air temperature, pressure, relative humidity, wind and precipitation. The visualization and analytical platform has been implemented for 2-m surface temperature. The platform gives Armenian State Hydrometeorological and Monitoring Service analytical capabilities to analyze the in-situ observations, model and satellite image data per station and region for a given period.

Published
2018
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7. Community detection: Comparison of state of the art algorithms

Author

Josiane Mothe, Mariam Haroutunian, Karen Mkhitaryan, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), National Academy of Sciences of the Republic of Armenia (ARMENIA), Systèmes d’Informations Généralisées (IRIT-SIG), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse - Jean Jaurès (UT2J), Institute for Informatics and Automation Problems, NAS of Armenia, and Institut National Polytechnique de Toulouse - INPT (FRANCE)

Subjects
Théorie de l'information, Community detection, Network science, Approximation algorithm, Recherche d'information, 02 engineering and technology, Stochastic block mode, Complex network, 01 natural sciences, Task (project management), [INFO.INFO-IT]Computer Science [cs]/Information Theory [cs.IT], Stochastic block model, [INFO.INFO-IR]Computer Science [cs]/Information Retrieval [cs.IR], 020204 information systems, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, State (computer science), 010306 general physics, Cluster analysis, Social network analysis, Algorithm
Abstract

International audience; Real world complex networks may contain hidden structures called communities or groups. They are composed of nodes being tightly connected within those groups and weakly connected between them. Detecting communities has numerous applications in different sciences such as biology, social network analysis, economics and computer science. Since there is no universally accepted definition of community, it is a complicated task to distinguish community detection algorithms as each of them use a different approach, resulting in different outcomes. Thus large number of articles are devoted to investigating community detection algorithms, implementation on both real world and artificial data sets and development of evaluation measures. In this article several state of the art algorithms and evaluation measures are studied which are used in clustering and community detection literature. The main focus of this article is to survey recent work and evaluate them using artificially generated networks.

Published
2017

8. SaaS for Energy Efficient Utilization of HPC Resources of Linear Algebra Calculations

Author

Georges Da Costa, Wahi Narsisian, Hrachya Astsatryan, Institute for Informatics and Automation Problems, NAS of Armenia, Système d’exploitation, systèmes répartis, de l’intergiciel à l’architecture (IRIT-SEPIA), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III - Paul Sabatier (UT3), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), National Academy of Sciences of the Republic of Armenia (ARMENIA), and Institut National Polytechnique de Toulouse - INPT (FRANCE)

Subjects
[INFO.INFO-AR]Computer Science [cs]/Hardware Architecture [cs.AR], Service (systems architecture), General Computer Science, Computer science, Real-time computing, Système d'exploitation, Réseaux et télécommunications, Cloud computing, 7. Clean energy, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Architectures Matérielles, Cloud service, DVFS, Linear algebra, Energy efficient utilization, business.industry, Software as a service, Supercomputer, Systèmes embarqués, Energy accounting, Reliability engineering, HPC, Alternative energy, [INFO.INFO-ES]Computer Science [cs]/Embedded Systems, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], business, Energy (signal processing), Efficient energy use
Abstract

International audience; The most important factor of High performance computing (HPC) systems nowadays is to limit or decrease the power consumption while preserving a high utilization. And with the availability of alternative energy, which powers such systems, there is a need to maximize the usage of alternative energy over brown power. For now, the usage of alternative energy is varying in time due to different factors such as sunny days, the wind, etc. and it is crucial to have an energy-aware algorithm to maximize the usage of this energy. In this paper a SaaS service is presented to optimize a usage of alternative energy, to reduce the power consumption and to preserve a best possible percentage of resource utilization.

Published
2017

9. Energy Optimization Methodology for e-Infrastructure Providers

Author

Astsatryan, Hrachya, Narsisian, Wahi, Kocharyan, Aram, Da Costa, Georges, Hankel, Albert, Oleksiak, Ariel, Institute for Informatics and Automation Problems, NAS of Armenia, Système d’exploitation, systèmes répartis, de l’intergiciel à l’architecture (IRIT-SEPIA), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III - Paul Sabatier (UT3), SURFnet (Utrecht, Pays-Bas), SURFnet (NETHERLANDS), Poznan Supercomputing and Networking Center (PSNC), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), National Academy of Sciences of the Republic of Armenia (ARMENIA), Poznan Supercomputing and Networking Center - PSNC (POLAND), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)

Subjects
[INFO.INFO-AR]Computer Science [cs]/Hardware Architecture [cs.AR], Système d'exploitation, Réseaux et télécommunications, Systèmes embarqués, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Architectures Matérielles, Green ICT, Virtualization, Nesus, E-infrastructure, [INFO.INFO-ES]Computer Science [cs]/Embedded Systems, DVFS, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], Energy optimisation, Memory ballooning
Abstract

International audience; The environmental protection is a dominant concern for all types of industries, organizations, and governments. In this regard, the reduction of the energy consumption is substantial in bringing down the CO2 gas emission, which is considered as an important factor causing global warming. The e-infrastructure service providers, such as National Research and Education Networks or National Grid Initiatives have crucial role in the context of energy awareness because the energy consumption of the networking, data, and computational infrastructures keeps increasing exponentially over the time. In addition to this, scientific gateways and cloud services are becoming more significant to tackle scientific and societal challenges. Therefore, there is a need to provide robust and reliable services taking into account energy consumption aspect of e-infrastructures. The aim of the article is to introduce an energy optimization methodology for the beneficiaries of the e-infrastructures to explore, optimize, and report the energy consumption and CO2 emission of data, computing, and networking facilities. The suggested methodology has been implemented within the Armenian e-infrastructure aiming at the reduction of the energy consumption and thereby the CO2 emission.

Published
2017

10. Dynamic voltage and frequency scaling for 3D Classical Spin Glass application

Author

Tom Gurout, Hakob Abajyan, Hrachya Astsatryan, Georges Da Costa, Wahi Narsisian, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), National Academy of Sciences of the Republic of Armenia (ARMENIA), Institut National Polytechnique de Toulouse - INPT (FRANCE), Institute for Informatics and Automation Problems, NAS of Armenia, Système d’exploitation, systèmes répartis, de l’intergiciel à l’architecture (IRIT-SEPIA), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, and Université Toulouse III - Paul Sabatier (UT3)

Subjects
[INFO.INFO-AR]Computer Science [cs]/Hardware Architecture [cs.AR], Engineering, Spin glass, Système d'exploitation, Réseaux et télécommunications, Context (language use), 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Architectures Matérielles, 0103 physical sciences, Electronic engineering, DVFS, 010306 general physics, Frequency scaling, business.industry, Mode (statistics), Energy consumption, Spin-chains, Supercomputer, Systèmes embarqués, Energy efficiency, Embedded system, HPC, [INFO.INFO-ES]Computer Science [cs]/Embedded Systems, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], business, Voltage, Efficient energy use, 3D
Abstract

International audience; The power consumption of large-scale high performance computing (HPC) systems is becoming a crucial challenge in the context of increasing the performance regardless of energy consumption [1]. Therefore, finding ways to improve energy efficiency has become a main issue for HPC applications. Dynamic voltage and frequency scaling (DVFS) is a widely used and powerful technique for reducing energy consumption in modern processors. The present paper investigates energy efficiency of 3D Classical Spin Glass [2], [3] application using the performance, ondemand and powersave modes of DVFS method. The series of experiments show that the execution time of OnDemand and PowerSave is the same, while the OnDemand mode is better due to the power consumption and frequency balance for the system.

Published
2015

11. From elongated spanning trees to vicious random walks

Author

V.S. Poghosyan, Alexander Gorsky, Sergei Nechaev, V. B. Priezzhev, Institute of Theoretical and Experimental Physics [Moscow] (ITEP), National Research Center 'Kurchatov Institute' (NRC KI), Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), P. N. Lebedev Physical Institute of the Russian Academy of Sciences [Moscow] (LPI RAS), Russian Academy of Sciences [Moscow] (RAS), Institute for Informatics and Automation Problems, NAS of Armenia, Bogoliubov Laboratory of Theoretical Physics [Dubna] (BLTP), and Joint Institute for Nuclear Research (JINR)

Subjects
High Energy Physics - Theory, Nuclear and High Energy Physics, [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], FOS: Physical sciences, 01 natural sciences, 010305 fluids & plasmas, Combinatorics, Correlation function, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], 0103 physical sciences, [PHYS.COND.CM-SM]Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech], 010306 general physics, Large distance, Scaling, Condensed Matter - Statistical Mechanics, Mathematical Physics, Physics, Spanning tree, Statistical Mechanics (cond-mat.stat-mech), [PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th], Spanning forest, Mathematical Physics (math-ph), Random walk, Square lattice, High Energy Physics - Theory (hep-th), Exponent
Abstract

Given a spanning forest on a large square lattice, we consider by combinatorial methods a correlation function of $k$ paths ($k$ is odd) along branches of trees or, equivalently, $k$ loop--erased random walks. Starting and ending points of the paths are grouped in a fashion a $k$--leg watermelon. For large distance $r$ between groups of starting and ending points, the ratio of the number of watermelon configurations to the total number of spanning trees behaves as $r^{-\nu} \log r$ with $\nu = (k^2-1)/2$. Considering the spanning forest stretched along the meridian of this watermelon, we see that the two--dimensional $k$--leg loop--erased watermelon exponent $\nu$ is converting into the scaling exponent for the reunion probability (at a given point) of $k$ (1+1)--dimensional vicious walkers, $\tilde{\nu} = k^2/2$. Also, we express the conjectures about the possible relation to integrable systems., Comment: 27 pages, 6 figures

Published
2012
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12. The bistability of higher-order differences of discrete periodic signals

Author

Ravi P. Agarwal, AY Shahverdian, RB Benosman, Institute for Informatics and Automation Problems, NAS of Armenia, Department of mathematics, Texas AM University, Institut de la Vision, Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Partial differential equation, Algebra and Number Theory, Series (mathematics), Dynamical systems theory, Bistability, Computation, Applied Mathematics, Mathematical analysis, Binary number, higher-order differences, discrete-time signals, Bounded function, Ordinary differential equation, discrete dynamical systems, [INFO]Computer Science [cs], Analysis, Mathematics
Abstract

International audience; A theorem on higher-order absolute differences taken from successive terms of bounded sequences is proved. This theorem establishes the property of bistability of such difference series and suggests a method for converting periodic discrete-time signals into the binary digital form based only on the computation of absolute differences.

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13. Study of different heterocycles showing significant anti-severe acute respiratory syndrome 2 activity in vitro and in vivo .

Author

Yengoyan A, Gomktsyan T, Pivazyan V, Ghazaryan E, Shainova R, Karapetyan A, Avetyan D, Aslanyan L, Baroyan K, Tuzikov A, Sargsyan M, Baghdasaryan B, Bayramyan N, Hakobyan S, Poghosyan A, Avetisyan A, Avagyan H, Hakobyan L, and Zaven K

Abstract

Background and Aim: With the emergence of severe acute respiratory syndrome-related coronavirus (SARS-CoV-2), antiviral drug development has gained increased significance due to the high incidence and potentially severe complications of the resulting coronavirus infection. Heterocycle compounds, acting as antimetabolites of DNA and RNA monomers, rank among the most effective antiviral drugs. These compounds' antiviral effects on various SARS-CoV-2 isolates, as found in existing data collections, form the basis for further research. The aim of this study was to examine the possible antiviral effect of some originally synthesized heterocyclic compounds., Materials and Methods: The main methods were cell culturing, cytotoxicity assay, qRT-PCR assay, tissue and blood cells analysis, and micro-computed tomography (micro-CT) imaging., Results: In both in vitro and in vivo conditions, the elimination of SARS-Cov-2 occurred significantly earlier after administration of the compounds compared to the control group. In hamsters, the primary symptoms of coronavirus disease disappeared following administration of heterocycle compounds., Conclusion: Using delta and omicron strains of the SARS-CoV-2 virus, newly created heterocycle compound analogs dramatically reduced SARS-CoV-2 multiplication, resulting in a drop in viral RNA load in the supernatant under in vitro conditions. Improvements in pathological manifestations in the blood, bone marrow, and internal organs of hamsters demonstrated that heterocycle compounds inhibited SARS-CoV-2 replication both in vitro and in vivo ., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Aleksandr, et al.)

Published
2024
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14. Influence of hydrometeorological indices on electrolytes and trace elements homeostasis in patients with ischemic heart disease.

Author

Babayan LA, Hayrapetyan HA, Gulyan AK, Danoyan HE, Vardanyan HA, Gasparyan NA, Sarafyan PK, Grigoryan SG, and Harutyumyan TG

Subjects
Circadian Rhythm, Electrolytes, Homeostasis, Humans, Myocardial Ischemia, Trace Elements
Abstract

One hundred patients with ischemic heart disease and 70 healthy subjects were on unified regimen. Urine was collected with 4-h proportions during 3-5 days (72-120 h). Each portion of urine was analyzed for macro- (Na, K, P, Cl, Ca, Mg) and microelements (Fe, Cu, Zn, Cr, Cd, V). Temporal structure (biological and hydrometeorological indices) parameters have been estimated by nonlinear least squares method for sinusoidal rhythms and dispersion analysis for nonsinusoidal rhythms. Data of weather indices were received from the hydrometeorological service of the Republic of Armenia in 2015 at 3-h intervals. Statistically significant rhythms were observed in healthy subjects in 91% cases of 593 rhythmological investigations of water-mineral homeostasis. Acrophases of water-mineral homeostasis mostly had individual nature. Healthy subjects' rhythms of water-mineral excretion were depending on rhythms of hydrometeorological indices and were characterized with significant correlative connections. Acrophases of indices of water-mineral homeostasis mostly were outstripping the acrophases of the rhythms of hydrometeorological indices. Chronostructure of water-mineral homeostasis in patients with ischemic heart disease was characterized with infradian and circadian fluctuations. In case of individuals with ischemic heart disease, statistically significant correlative connections between rhythms of water-mineral excretion and rhythms of hydrometeorological indices differ in comparison with the results of practically healthy individuals. In patients with ischemic heart disease, acrophases of biorhythms often were concurrent or delayed relative to the acrophases of the rhythms of hydrometeorological indices.

Published
2020
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15. Whole-genome-based phylogeny of African swine fever virus.

Author

Aslanyan L, Avagyan H, and Karalyan Z

Abstract

Aim: A genome-scale phylogenetic analysis was used to infer the evolutionary dynamics of Asfarviridae - African swine fever virus (ASFV) - and better define its genetic diversity., Materials and Methods: All complete ASFV genomes from NCBI's resource as of March 2020 were used. The phylogenetic analysis used maximum likelihood and neighbor-joining methods. The evolutionary models detection was done with the help of the package of programs MEGA-X. Algorithms were used to build phylogenetic trees for type B DNA polymerases of ASFV (n=34) and HcDNAV (n=2), as an external group., Results: An expedient categorization of the Asfarviridae family uses five clades. Genotype 1 (except for LIV 5/40 virus isolate) as well genotype 7 are assigned to the alpha clade; genotype 2 to the beta clade; genotypes 8, 9, and 10 to the gamma clade; genotype 5 to the delta clade; and genotypes 3, 4, and 20, as well as genotype 22 and the LIV 5/40 isolate to the epsilon clade. Branch lengths on the phylogenetic tree are proportional to genetic distance along the branch. Branches at the phylogenetic tree of Asfarviridae are much shorter than branches for Baculoviridae. Shorter branches in ASFVs population suggest that Asfarviridae evolved relatively recently and remain more closely related., Conclusion: We suggest applying more robust standards using whole genomes to ensure the correct classification of ASFV and maintain phylogeny as a useful tool., (Copyright: © Aslanyan, et al.)

Published
2020
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16. Numerical study of the correspondence between the dissipative and fixed-energy Abelian sandpile models.

Author

Poghosyan SS, Poghosyan VS, Priezzhev VB, and Ruelle P

Abstract

We consider the Abelian sandpile model (ASM) on the square lattice with a single dissipative site (sink). Particles are added one by one per unit time at random sites and the resulting density of particles is calculated as a function of time. We observe different scenarios of evolution depending on the value of initial uniform density (height) h(0). During the first stage of the evolution, the density of particles increases linearly. Reaching a critical density ρ(c)(h(0)), the system changes its behavior and relaxes exponentially to the stationary state of the ASM with density ρ(s). Considering initial heights -1 ≤ h(0) ≤ 4, we observe a dramatic decrease of the difference ρ(c)(h(0)) - ρ(s) when h(0) is zero or negative. In parallel with the ASM, we consider the conservative fixed energy sandpile (FES). The extensive Monte Carlo simulations show that the threshold density ρ(th)(h(0)) of the FES converges rapidly to ρ(s) for h(0) < 1.

Published
2011
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