Wyniki wyszukiwania - BazTech

1

RED-LE: A Revised Algorithm for Active Queue Management

Hassan Samuel O.

Journal of Telecommunications and Information Technology

|

2022

|

nr 2

91--97

EN

The random early detection (RED) algorithm was developed in 1993. Nearly three decades later, several improved variants have been proposed by scientists. The use of a (pure) linear function for computing packet drop probability has turned out to be a disadvantage, leading to the problem of large delays. Such a problem may be addressed by using linear and non-linear (i.e. as exponential) packet drop probability functions. This paper proposes a revised RED active queue management algorithm named RED-linear exponential (RED-LE). This variant involves an interplay of linear and exponential drop functions, in order to improve the performance of the original RED algorithm. More importantly, at low and moderate network traffic loads, the RED-LE algorithm employs the linear drop action. However, for high traffic loads, RED-LE employs the exponential function for computing the packet drop probability rate. Experimental results have shown that RED-LE effectively controls congestion and offers an improved network performance under different traffic loads.

2

Bezpieczeństwo elektromagnetyczne węzłów wieloprotokołowych w systemach rozproszonych czasu rzeczywistego

Kwiecień A., Maćkowski M.

Napędy i Sterowanie

|

2014

|

R. 16, nr 12

112--117

PL

Tematyka przedstawiona w niniejszej pracy skupia się na testowaniu zachowania wieloprotokołowego węzła komunikacyjnego w momencie wystąpienia zakłóceń elektromagnetycznych w torze transmisyjnym. Węzeł taki – szczególnie w chwilowych przeciążeniach sieci lub w sytuacjach awaryjnych polegających na uszkodzeniu systemu transmisyjnego lub będących wynikiem zaistniałych na obiekcie przemysłowym zdarzeń – jest w stanie rozładować wzmożony ruch w sieci lub zapewnić bezpieczeństwo transmisji. W pracy wskazano na potencjalne możliwości wykorzystania sprzętu laboratoryjnego do pomiarów EMC (ElectroMagnetic Compatybility) w procesie testowania urządzenia i symulowania rzeczywistych zagrożeń (zakłóceń), które mogą wystąpić na obiekcie. Wyniki końcowe wskazują na prawidłowe funkcjonowanie zaproponowanego algorytmu wymian (query distributor) i możliwość automatycznego dostosowania topologii systemu w momencie wystąpienia zakłóceń elektromagnetycznych.

EN

The main idea presented in the paper focuses on testing behavior of multi-network interface node while electromagnetic disturbances in transmission line occur. Such node is able to unload an increased traffic in network or provide the security of transmission, especially in cases of temporary overloads, system failure – damage of transmission system, or events occurring in industry area. The authors marked the potential possibilities of using equipment for EMC (Electromagnetic Compatibility) measurements in the process of testing and simulating the real threats (disturbances) that may appear in the object. The final results point out the correct work of developed query distributor system and the opportunities of automatic adjustment of the network topology in case of electromagnetic disturbances.

3

Fault tolerance in networked control systems under intermittent observations

Georges J. P., Theilliol D., Cocquempot V., Ponsart J. C., Aubrun C.

International Journal of Applied Mathematics and Computer Science

|

2011

|

Vol. 21, no 4

639-648

EN

This paper presents an approach to fault tolerant control based on the sensor masking principle in the case of wireless networked control systems. With wireless transmission, packet losses act as sensor faults. In the presence of such faults, the faulty measurements corrupt directly the behaviour of closed-loop systems. Since the controller aims at cancelling the error between the measurement and its reference input, the real outputs will, in such a networked control system, deviate from the desired value and may drive the system to its physical limitations or even to instability. The proposed method facilitates fault compensation based on an interacting multiple model approach developed in the framework of channel errors or network congestion equivalent to multiple sensors failures. The interacting multiple model method involved in a networked control system provides simultaneously detection and isolation of on-line packet losses, and also performs a suitable state estimation. Based on particular knowledge of packet losses, sensor fault-tolerant controls are obtained by computing a new control law using fault-free estimation of the faulty element to avoid intermittent observations that might develop into failures and to minimize the effects on system performance and safety.

4

Mechanizmy kontroli nasilenia ruchu a jakość usług w sieciach TCP/IP/ATM

Wójcicki R.

Studia Informatica

|

2003

|

Vol. 24, nr 2B

71-80

PL

W sieciach TCP/IP/ATM stosowane są algorytmy kontroli ruchu na poziomach poszczególnych protokołów, które powinny pozwalać na optymalne wykorzystanie zasobów sieci, jak i zapewnienie wymaganych dla wszystkich użytkowników kategorii usług oraz zabezpieczenie się przed niekontrolowanym przeciążeniem ruchu w sieci. Algorytmy te mogą jednak interefować ze sobą, co może dawać nie zawsze korzystny ich wpływ na wydajność sieci.

EN

Traffic management is a key problem in designing high speed networks. The goal of traffic management is to control network congestion, efficiently utilize network resources and deliver quality of services to users, especially in TCP/IP/ATM networks. TCP and ATM implements a variety of flow and congestion control mechanisms, which can effect mutually interfere.