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1
Energooszczędne centrum przetwarzania danych
Niewiadomska-Szynkiewicz E., Arabas P.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2018
|
nr 8-9
609--614, CD
PL
Wzrostowi zapotrzebowania na moc obliczeniową oraz natężenie ruchu w sieci IP nie towarzyszy obecnie pojawianie się technologii chroniących operatorów i środowisko naturalne przed analogicznym wzrostem zapotrzebowania na energię w sektorze. Artykuł 1 przedstawia wyniki badań, których celem jest opracowanie koncepcji i realizacja systemu komputerowego do energooszczędnego sterowania obciążeniem rozproszonego centrum przetwarzania danych oraz szybkością pracy jednostek obliczeniowych i urządzeń sieciowych przekazujących komunikaty z danymi. Niniejsza praca prezentuje propozycję dwupoziomowej struktury zarządzania przydziałem bloków zadań do klastrów, a następnie do poszczególnych serwerów obliczeniowych. Decyzje o alokacji zadań są podejmowane w wyniku rozwiązania zadania minimalizacji zużycia zasobów energetycznych systemu, przy założeniu zagwarantowania wymaganego poziomu jakości usług.
EN
The proposition of a framework for energy-aware control in a large scale HPC (High Performance Computing) system is presented and discussed. The implementation consists of a global computing resource manager that is implemented in the central control level, energy-efficient backbone network connecting computing clusters and data centers and a local resource manager implemented in each cluster. The decisions about activity and power status of computer and network equipment are determined by solving the problem of minimizing the energy used by the whole HPC system. A simulation-based optimization scheme is utilized to calculate optimal allocation of a set of tasks to clusters.
2
Content available Energy Aware Data Centers and Networks: a Survey
Arabas P.
Journal of Telecommunications and Information Technology
|
2018
|
nr 4
26--36
EN
The past years have brought about a great variety of clusters and clouds. This, combined with their increasing size and complexity, has resulted in an obvious need for power-saving control mechanisms. Upon presenting a basis on which such solutions - namely low-level power control interfaces, CPU governors and network topologies – are constructed, the paper summarizes network and cluster resources control algorithms. Finally, the need for integrated, hierarchical control is expressed, and specific examples are provided.
3
Częstość występowania wybranych triad w sieci połączeń między systemami autonomicznymi jako wskaźnik niektórych typów anomalii ruchu
Arabas P., Karpowicz M.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2016
|
nr 8-9
1179--1184, CD
PL
W pracy przedstawiono próbę stworzenia grafu systemów autonomicznych na podstawie danych ruchowych zarejestrowanych na pojedynczym węźle sieci. Tak uzyskany graf, przypominający sieci ego znane z zastosowań związanych z serwisami społecznościowymi poddano analizie triad. Uzyskane wyniki świadczą o podobieństwach grafów występujących w obu przypadkach, pokazują także możliwość obserwacji własności topologicznych będących odzwierciedleniem niektórych anomalii ruchu. Pozwala to zastosować techniki analizy sieci społecznych do badania zagrożeń informatycznych.
EN
The work presents an attempt to construct and analyze autonomus system network basing on traffic information gathered on the single network node. So constructed graph reseambles in many aspects ego networks known from social media analysis. Analysis of basic graph properties confirms these similarities and suggests that some local topological features may be used to investigate traffic anomalies allowing to apply social network analysis tools to network security problems.
4
Content available remote Wykorzystanie informacji z rejestrów procesora do identyfikacji modelu poboru mocy przez serwer
Arabas P., Karpowicz M.
Przegląd Elektrotechniczny
|
2016
|
R. 92, nr 3
34--41
PL
Model poboru mocy jest istotnym elementem rozwiązań zwiększających efektywność energetyczną serwerów sieciowych. Należy spodziewać się że profile poboru mocy zależą od zastosowania danej maszyny. Przeprowadzenie szczegółowych eksperymentów pomiarowych wymaga odpowiedniego sprzętu – przede wszystkim miernika mocy. Tematem przedstawionej pracy jest próba znalezienia zależności między całkowitą mocą pobieraną przez serwer a mocą odczytaną z rejestrów msr procesora, Wyznaczenie takiej zależności pozwoli na stosunkowo szybkie dostrajanie generycznego modelu poboru mocy do konkretnego zastosowania i konfiguracji sprzętowej.
EN
Precise model of power consumption is crucial for improving energy effectiveness of network servers. Model construction requires numerous measurement experiments employing appropriate equipment – power meter and data collection system. The subject of paper is assessment if power statistics available via msr registers of some Intel processors may be correlated to total power consumed by the server. Finding such relation will allow to construct generic total power consumption model which may be easily tuned to suit specific application.
5
Content available Server Workload Model Identification: Monitoring and Control Tools for Linux
Karpowicz M., Arabas P.
Journal of Telecommunications and Information Technology
|
2016
|
nr 2
5--12
EN
Server power control in data centers is a coordinated process carefully designed to reach multiple data center management objectives. The main objectives include avoiding power capacity overloads and system overheating, as well as fulfilling service-level agreements (SLAs). In addition to the primary goals, server control process aims to maximize various energy efficiency metrics subject to reliability constraints. Monitoring of data center performance is fundamental for its efficient management. In order to keep track of how well the computing tasks are processed, cluster control systems need to collect accurate measurements of activities of cluster components. This paper presents a brief overview of performance and power consumption monitoring tools available in the Linux systems.
6
Content available Energy-saving Algorithms for the Control of Backbone Networks: A Survey
Kamola M., Niewiadomska-Szynkiewicz E., Arabas P., Sikora A.
Journal of Telecommunications and Information Technology
|
2016
|
nr 2
13--20
EN
The rapid growth of energy demand by wired IP networks can be mitigated on hardware and software levels. While upgrading to more efficient transmission media still brings biggest savings, we take a look here at power-saving algorithms that combine the capability of setting networking equipment in arbitrary energy states which, combined with profound knowledge of the network traffic matrix, leads to considerable complex optimization problem formulations. Alternatively, lightweighted heuristic approaches are presented, built on much simpler network model but still capable to perform energy-efficient traffic engineering.
7
Content available Application of Social Network Inferred Data to Churn Modeling in Telecoms
Gruszczyński W., Arabas P.
Journal of Telecommunications and Information Technology
|
2016
|
nr 2
77--86
EN
The subject of this work is the use of social network analysis to increase the effectiveness of methods used to predict churn of telephony network subscribers. The social network is created on the basis of operational data (CDR records). The result of the analysis is customer segmentation and additional predictor variables. Proposed hybrid predictor employs set of regression models tuned to specific customer segments. The verification was performed on data obtained from one of the Polish operators.
8
Content available Simultaneous routing and flow rate optimization in energy-aware computer networks
Jaskóła P., Arabas P., Karbowski A.
International Journal of Applied Mathematics and Computer Science
|
2016
|
Vol. 26, no. 1
231--243
EN
The issue of energy-aware traffic engineering has become prominent in telecommunications industry in the last years. This paper presents a two-criteria network optimization problem, in which routing and bandwidth allocation are determined jointly, so as to minimize the amount of energy consumed by a telecommunication infrastructure and to satisfy given demands represented by a traffic matrix. A scalarization of the criteria is proposed and the choice of model parameters is discussed in detail. The model of power dissipation as a function of carried traffic in a typical software router is introduced. Then the problem is expressed in a form suitable for the mixed integer quadratic programming (MIQP) solver. The paper is concluded with a set of small, illustrative computational examples. Computed solutions are implemented in a testbed to validate the accuracy of energy consumption models and the correctness of the proposed traffic engineering algorithm.
9
Content available Maintaining the feasibility of hard real-time systems with a reduced number of priority levels
Qureshi M. B., Alrashed S., Min-Allah N., Kołodziej J., Arabas P.
International Journal of Applied Mathematics and Computer Science
|
2015
|
Vol. 25, no. 4
709--722
EN
When there is a mismatch between the cardinality of a periodic task set and the priority levels supported by the underlying hardware systems, multiple tasks are grouped into one class so as to maintain a specific level of confidence in their accuracy. However, such a transformation is achieved at the expense of the loss of schedulability of the original task set. We further investigate the aforementioned problem and report the following contributions: (i) a novel technique for mapping unlimited priority tasks into a reduced number of classes that do not violate the schedulability of the original task set and (ii) an efficient feasibility test that eliminates insufficient points during the feasibility analysis. The theoretical correctness of both contributions is checked through formal verifications. Moreover, the experimental results reveal the superiority of our work over the existing feasibility tests by reducing the number of scheduling points that are needed otherwise.
10
Content available Network resilience analysis: review of concepts and a country level. Case study
Kamola M., Arabas P.
Computer Science
|
2014
|
Vol. 15 (3)
311--327
EN
This paper presents the rationale behind performing an analysis of Internet resilience in the sense of maintaining a connection of autonomous systems in the presence of failures or attacks — on a level of a single country. Next, the graph of a network is constructed that represents interconnections between autonomous systems. The connectivity of the graph is examined for cases of link or node failure. Resilience metrics are proposed, focusing on a single autonomous system or on overall network reliability. The process of geographic location of networking infrastructure is presented, leading to an analysis of network resilience in the case of a joint failure of neighboring autonomous systems.
11
Econet - energooszczędne techniki dla przewodowych sieci komputerowych
Kamola M., Arabas P., Wiśniewski T., Niewiadomska-Szynkiewicz E., Malinowski K., Karpowicz M., Sikora A., Marks M., Mincer M.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2012
|
nr 8-9
650-655
PL
Przedstawiono projekt Econet, opracowujący mechanizmy skoordynowanego oszczędzania energii na wszystkich poziomach funkcjonalnych i we wszystkich obszarach topologicznych sieci. Prace, wykonywane w projekcie przez NASK oraz Instytut Automatyki i Informatyki Stosowanej PW, skupiają się na stworzeniu struktury i algorytmów sterowania siecią. Dokonano analizy zużycia energii we współczesnym sprzede, opisano projekt interfejsu dla energooszczędnych urządzeń, zadania optymalizacji energii w obszarze sieci oraz narzędzia symulacyjnej weryfikacji konstruowanych algorytmów.
EN
Econet, whose goal is to develop energy-efficient network hardware and control logic, is presented. The main contribution of Research and Academic Computer Network and of Inst. of Computation and Control Engineering to the project consists in creation of a network control structure and algorithms. Power consumption analysis for contemporary devices, API design for green networking components, energy optimization problem formulation and tools for verification through simulation, arę presented as the current main project achievements by the authors.
12
Content available Analysis and Modeling of Domain Registration Process
Arabas P., Jaskóła P., Kamola M., Karpowicz M.
Journal of Telecommunications and Information Technology
|
2012
|
nr 2
63-73
EN
The paper presents analysis of the domain name reservation process for the polish .pl domain. Two models of various time scale are constructed and finally combined to build long range high resolution model. The results of prediction are verified using real data.
13
Content available Performance Evaluation of Signaling in the IP QoS System
Tarasiuk H., Śliwiński J., Arabas P., Jaskóła P., Góralski W.
Journal of Telecommunications and Information Technology
|
2011
|
nr 3
12-20
EN
The IP QoS System is based on next generation networks (NGN) and differentiated services (DiffServ) architectures. Its main part is a signaling system, which allows to send a request from a user to the system for establishing new connection with predefined quality of service assurance. In this paper we present trial results of the proposed signalling system. The experiments were performed to measure setup delay utilizing artificial call generator/analyzer. To obtain results we assumed different distributions of interarrival and call holding times based on the literature. The results show that the setup delay strongly depends on access time to network devices, however also on the assumed call holding time models.
14
Content available Dynamic Contracting of IP Services - System Architecture and Prototype
Arabas P., Kamola M.
Journal of Telecommunications and Information Technology
|
2011
|
nr 2
43-52
EN
Proposition of architecture and implementation of prototype system for dynamic contracting IP services is presented. The system serves requests issued by users demanding setting up network service of specified parameters. DiffServ technology together with traffic engineering and admission control are used. Implementation details and results of tests are described. Necessary extensions and possibility of commercialization of such a system are discussed.
15
Content available Dynamically established transmission paths in the future Internet - proposal of a framework
Kamola M., Arabas P.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2011
|
Vol. 59, nr 3
357-366
EN
An idea of a global system for dynamic contracting data paths in the global IP network is presented. System scalability and efficiency is based on the current natural hierarchy of Internet providers. Architecture of the bandwidth market service accomplishing operation of such system is outlined. Benefits from dynamic provisioning of such dedicated paths with QoS guarantees are shown. Utilization of various technologies for this system is discussed.
16
Świadczenie usług przesyłowych z gwarancjami jakości w sieci lP - idea i prototyp systemu
Arabas P., Kamola M.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2010
|
nr 1
9-18
PL
Zaproponowano architekturę i przedstawiono wyniki badań prototypu systemu dynamicznej kontraktacji usług przesyłowych w sieci IP Naszkicowano podział funkcjonalny systemu i sprecyzowano zadania poszczególnych modułów -również dla scenariusza z interakcją wielu operatorów. Przedstawiono szczegóły implementacji i wyniki testów prototypu takiego systemu. Wyniki testów potwierdzają możliwość wdrożenia systemu w wersji dopracowanej i kompletnej, w sieci roboczej operatora.
EN
An architecture and a prototype of a system for dynamic contract making for QoS assured transmission services is presented in this paper. Operation of system major blocks is presented, also for a scenario with transmission endpoints in different ISPs. Implementation details for DiffServ technology with appropriate CAC and route planning strategies arę given. Test results focused on the system efficiency and effectiveness are discussed. The conclusion is that deployment of a system like the one presented could positively affect the port-folio and profit of ISP products, as well as give the customer possibility to dynamically allocate itself tailored services.
17
Content available remote Periodic Coordination in Hierarchical Air Defence Systems
Arabas P., Malinowski K.
International Journal of Applied Mathematics and Computer Science
|
2001
|
Vol. 11, no 2
493-513
EN
The subject of this work is the defence planning of a point target against an air attack. The defence system is decomposed into a number of sectors. A direct method of coordination is used at the upper level, while the sectors use a discrete-time event-based model and the description of uncertainty by multiple scenarios of an attack. The resulting problems are solved using linear programming. A comparison of two coordination strategies for realistic attack scenarios and an analysis of effectiveness are provided.
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