PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 25

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  system kolejkowy
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
1
Content available Analiza porównawcza protokołów przesyłania wiadomościasynchronicznych w systemach kolejkowych
Derlatka Grzegorz, Kopniak Piotr
Journal of Computer Sciences Institute
|
2023
|
Vol. 26
29--32
PL
W tym artykule została przedstawiona analiza wydajności dwóch protokołów obsługiwanych przez systemy kolejkowe, tj. protokołu MQTT (ang. MQ Telemetry Transport) oraz AMQP (ang. Advanced Message Queuing Protocol). Analiza ta została przeprowadzona z użyciem dwóch brokerów wiadomości - ActiveMQ oraz RabbitMQ. Analizie został poddany czas przesłania wiadomości wyznaczony na podstawie czasu wysłania i odebrania komunikatu dla obu protokołów w obu przytoczonych systemach kolejkowych. Testy zostały przeprowadzone przy pomocy własnych aplikacji napisanych w języku Java oraz szkielecie aplikacji Spring.
EN
This article presents an analysis of the performance of two protocols supported by queuing systems, i.e. MQTT and AMQP. This analysis was performed using two message brokers - ActiveMQ and RabbitMQ. The time of sending the message was analyzed, determined on the basis of the time of sending and receiving the message for both protocols in both of the above-mentioned queuing systems. The tests were carried out using proprietary applications written in Java and the Spring application framework.
2
Content available Calculating steady-state probabilities of queueing systems using hyperexponential approximation
Zhernovyi Yuriy, Kopytko Bohdan
Journal of Applied Mathematics and Computational Mechanics
|
2019
|
Vol. 18, nr 2
111--122
EN
This article proposes an analysis of the results of the application of hyperexponential approximations with parameters of the paradoxical and complex type for calculating the steady-state probabilities of the G/G/n/m queueing systems with the number of channels n = 1, 2 and 3. The steady-state probabilities are solutions of a system of linear algebraic equations obtained by the method of fictitious phases. Approximation of arbitrary distributions is carried out using the method of moments. We verified the obtained numerical results using potential method and simulation models, constructed by means of GPSS World.
3
System z przelewem ruchu oraz kolejkami w zasobach pierwotnych oraz wtórnych
Kaliszan A., Kmiecik D.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2018
|
nr 8-9
660--665, CD
PL
W artykule zaprezentowano rezultaty badań wpływu stosowania kolejkowania zgłoszeń w hierarchicznych systemach z przelewami ruchu wielousługowego. Rozważane systemy składały się z kilku zasobów pierwotnych oraz jednego zasobu wtórnego. Systemom tym oferowane były wielousługowe strumienie ruchu. W badaniach określono wpływ struktury ruchu, pojemności kolejek, maksymalnego czasu przebywania w kolejce (ograniczony oraz nieograniczony) oraz zasobu, w którym wykorzystano kolejkowanie (zasoby pierwotne, zasoby alternatywne). Wnioski prezentowane w artykule zostały oparte na wyznaczonych prawdopodobieństwach blokady w systemach przelewowych.
EN
In this paper, the performance evaluation of call queuing in hierarchical systems with multi-service overflow traffic was presented. The considered system model consisted of a few primary resources and a single secondary resource servicing multi-service traffic streams. The study investigated the impact of the traffic structure, queue capacity, maximum queueing time (limited or unlimited) and the placement of queuing resources (primary resources or secondary resources). The presented results are based on determined blocking probabilities in the systems with overflow traffic.
4
Content available Multiline queueing system with random time limitations and limited buffer space
Tikhonenko O., Zając P.
Journal of Applied Mathematics and Computational Mechanics
|
2018
|
Vol. 17, nr 4
99--106
EN
In the paper, we investigate multi-server queueing systems with demands of random space requirements (volumes), in which buffer space is limited by constant value and queueing ore (and) service time are limited by exponentially distributed random variables. For such systems, stationary demands number distribution and loss probability are determined. Some numerical results are attached as well.
5
Content available Finding the expected revenues in Markov networks with positive and negative customers at a stationary regime
Matalytski M., Kopats D.
Journal of Applied Mathematics and Computational Mechanics
|
2018
|
Vol. 17, nr 1
49--60
EN
Finding the expected revenues in the queueing systems (QS) of open Markov G-networks of two types, with positive and negative customers and with positive customers and signals, has been described in the paper. A negative customer arriving to the system destroys one positive customer if at least one is available in the system, thus reducing the number of positive customers in the system by one. The signal, coming into an empty system (where there are no positive customers), does not have any impact on the network and immediately disappears from it. Otherwise, if the system is not empty, when it receives a signal, the following events can occur: the incoming signal instantly moves the positive customer from one QS into another with a certain probability, or with the other probability, the signal is triggered as a negative customer.
6
Content available From exhaustive vacation queues to preemptive priority queues with general interarrival times
Fiems D., De Vuyst S.
International Journal of Applied Mathematics and Computer Science
|
2018
|
Vol. 28, no. 4
695--704
EN
We consider the discrete-time G/GI/1 queueing system with multiple exhaustive vacations. By a transform approach, we obtain an expression for the probability generating function of the waiting time of customers in such a system. We then show that the results can be used to assess the performance of G/GI/1 queueing systems with server breakdowns as well as that of the low-priority queue of a preemptive MX+G/GI/1 priority queueing system. By calculating service completion times of low-priority customers, various preemptive breakdown/priority disciplines can be studied, including preemptive resume and preemptive repeat, as well as their combinations. We illustrate our approach with some numerical examples.
7
Content available Investigation into the bimodal transportation process by modelling rail module states
Lavrukhin O., Zapara V., Zapara Y., Shapatina O., Bogomazova G.
Transport Problems
|
2017
|
T. 12, z. 2
99--112
EN
The bimodal transportation process, which takes into account the modelling of rail module states, has been studied. The article demonstrates marked graphs of rail module states with and without running gear change in operation. It has been established which states have the greatest impact on the probability of a steady mode. The work has considered fractality of arrivals and its range in the queueing system with priorities.
8
Content available Expected volumes of requests in systems of the queueing network with a limited number of waiting places
Zając P., Matalytski M.
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics
|
2017
|
Vol. 22
141--160
EN
We present a method of finding the expected volume of requests in HM-network with homogeneous requests and bypass of the queueing systems of requests. The case was considered when the volume changes associated with the transitions between the states of the network are deterministic functions, depending on the state of the network and time, and the systems are single line. It is assumed that the probability of the states of the network systems, the parameters of the entrance flow of the requests and the service depend on the time.
9
Content available Analysis of an MAP/PH/1 queue with flexible group service
Brugno A., D’Apice C., Dudin A., Manzo R.
International Journal of Applied Mathematics and Computer Science
|
2017
|
Vol. 27, no. 1
119--131
EN
A novel customer batch service discipline for a single server queue is introduced and analyzed. Service to customers is offered in batches of a certain size. If the number of customers in the system at the service completion moment is less than this size, the server does not start the next service until the number of customers in the system reaches this size or a random limitation of the idle time of the server expires, whichever occurs first. Customers arrive according to a Markovian arrival process. An individual customer’s service time has a phase-type distribution. The service time of a batch is defined as the maximum of the individual service times of the customers which form the batch. The dynamics of such a system are described by a multi-dimensional Markov chain. An ergodicity condition for this Markov chain is derived, a stationary probability distribution of the states is computed, and formulas for the main performance measures of the system are provided. The Laplace–Stieltjes transform of the waiting time is obtained. Results are numerically illustrated.
10
Content available A queueing system with heterogeneous impatient customers and consumable additional items
Baek J., Dudina O., Kim C.
International Journal of Applied Mathematics and Computer Science
|
2017
|
Vol. 27, no. 2
367--384
EN
A single-server queueing system with a marked Markovian arrival process of heterogeneous customers is considered. Type-1 customers have limited preemptive priority over type-2 customers. There is an infinite buffer for type-2 customers and no buffer for type-1 customers. There is also a finite buffer (stock) for consumable additional items (semi-products, half-stocks, etc.) which arrive according to the Markovian arrival process. Service of a customer requires a fixed number of consumable additional items depending on the type of the customer. The service time has a phase-type distribution depending on the type of the customer. Customers in the buffer are impatient and may leave the system without service after an exponentially distributed amount of waiting time. Aiming to minimize the loss probability of type-1 customers and maximize throughput of the system, a threshold strategy of admission to service of type-2 customers is offered. Service of type-2 customer can start only if the server is idle and the number of consumable additional items in the stock exceeds the fixed threshold. Stationary distributions of the system states and the waiting time are computed. In the numerical example, we show some interesting effects and illustrate a possibility of application of the presented results for solution of optimization problems.
11
Content available remote On a Restricted Admissibility Compulsory Vacation Queue with Essential and Optional Services
Kalyanaraman R., Suvitha V.
Mathematica Applicanda
|
2016
|
Vol. 44, No. 2
223--245
EN
In this paper, we study a single server queueing system in which the customers arrive according to a Poisson process with two phases of services. The customers may require, with a certain probability, an optional secondary service upon completion of the two phases of essential service. The server takes a vacation compulsorily after completion of service to a customer. In addition the admission of the customer to the queue is based on a Bernoulli process. The model is studied using supplementary variable techniques. Some special models are derived and some illustrative cases are discussed. Also, the queue has been realized using simulation.
PL
Tematem tej pracy jest model serwera systemu kolejkowego z poissonowskim strumieniem zgłoszeń i obsługą podzieloną na dwie obowiązkowe fazy. Klienci mogą wymagać z pewnym prawdopodobieństwem opcjonalnej usługi dodatkowej po zakończeniu dwóch etapów podstawowych usługi. Po zakończeniu obsługi klienta następuje obowiązkowy przestój. Przy zajętym serwerze klienci dołączają do kolejki zgodnie z procesem Bernoulliego. Przy badaniu systemu stosowane są metody zmiennych dodatkowych. Pewne szczególne przypadki są analizowane szczegółowo. Ilustracją są wyniki eksperymentów symulacyjnych.
12
Analysis and optimization of queuing system with impatient customers using Matlab
Majewska K
Logistyka
|
2015
|
nr 2
554--559, CD1
PL
W artykule przedstawiono wyniki obliczeń parametrów systemu M/M/m/FIFO/∞ z niecierpliwymi klientami przyprowadzonych w programie Matlab. Zbadano wpływ zmian średni ego natężenia strumienia zgłoszeń oraz średniej długości kolejki na prawdopodobieństwo rezygnacji z kolejki. Dokonano wyliczeń liczby stacji obsługi przy dopuszczalnym prawdopodobieństwie rezygnacji klienta. Porównano działanie systemu z niecierpliwymi klientami do przypadku systemu z nieograniczonym czasem oczekiwania.
EN
The paper presents results of calculations of the parameters of M/M/m/FIFO/∞ system with impatient customers, such as mean service time and mean sojourn time, obtained in MATLAB software. The impact of the arrival rate and the abandonment rate on the probability of leaving the queue has been researched. The minimal number of service stations under acceptable probability of customer abandonment have been calculated.
13
Content available remote Wyznaczenie rozkładu objętości sumarycznej w jednoliniowym systemie kolejkowym z priorytetem bezwzględnym
Tikhonenko O.
Studia i Materiały / Europejska Uczelnia Informatyczno-Ekonomiczna w Warszawie
|
2014
|
Nr 2(8)
57--75
PL
W artykule przeanalizowano jednoliniowe systemy kolejkowe z priorytetem bezwzględnym przy założeniu, że zgłoszenie każdej klasy priorytetowej posiada objetość losową, od której zależy czas obsługi tego zgłoszenia. Założono również, że charakterystyki wspólnego rozkładu objetości zgłoszenia i jego czasu obsługi mogą być różne dla różnych klas priorytetowych. Dla rozpatrywanego systemu z nieograniczoną pojemnością pamięci otrzymano charakterystyki wspólnego rozkładu objetości sumarycznej zgłoszeń różnych klas priorytetowych.
EN
One-server preemptive priority queueing systems are analyzed under assumption that a demand of each priority has some random capacity and service time of the demand depends on its capacity. It is assumed that the joint characteristics of service time and demand capacity can be different for different priorities. For the system under consideration (with unbounded total capacity), characteristics of joint distribution of each priority total demand capacity are obtained.
14
Queueing performance of M/D/1 system with self-similar input
Włodarski P.
Logistyka
|
2014
|
nr 3
6713--6719
EN
Queueing systems are widely used in different fields of actual functioning with assumption that the arrival process is not correlated and has independent increments, Although it is associated with simple and more tractable form of statements, this can lead to inaccurate modeling and performance evaluation of analyzed process. In this article a more realistic attempt to examine the single lane traffic flow model is presented. It is based on the self-similar input process and the corresponding M/D/1 queueing model that approximates performance measures for different self-similarity levels. The main goal of this article is to investigate how much can be wrong using classic queueing systems with independent arrivals. In order to show the difference, the mean numbers of vehicles in the M/D/1 queueing system as well as the effective speed of vehicles in the single lane is presented as a result of simulation. Obtained values are compared to theoretical counterparts and discussed.
PL
Systemy kolejkowe są szeroko stosowane na różnych polach eksploatacji najczęściej przy założeniu że proces wejściowy kolejki nie jest skorelowany i zmienna losowa przyrostowa jest niezależna. Mimo uproszczeń w analizie i możliwości wyprowadzania różnych wyrażeń opisujących dany system kolejkowy, założenie to powoduje niedokładności przy ocenie efektywności badanego procesu. W artykule zaprezentowano bardziej realistyczne podejście modelowania przepływu na pojedynczym pasie ruchu bazujące na samopodobnym strumieniu wejściowym występującym w rzeczywistości w mniejszym lub większym stopniu oraz na odpowiadającym mu modelu kolejkowym M/D/1, dzięki któremu możliwe jest wyznaczenie miar efektywności dla różnych poziomów samopodobieństwa. Głównym celem jest zbadanie i pokazanie jak bardzo można mylić się, używając klasycznych modeli kolejkowych, dla których strumień danych wejściowych związany jest z niezależną zmienną losową. Aby pokazać różnice, skupiono się na zbadaniu średniej liczby pojazdów przebywających w systemie M/D/1, jak również efektywnej prędkości charakterystycznej dla przepływu pojazdów na pojedynczym pasie ruchu. Otrzymane wyniki zostały omówione, zaprezentowane przy pomocy wykresów i tabeli, jak również porównane z wartościami teoretycznymi.
15
Content available Analysis of an MMAP/PH1, PH2/N/∞ queueing system operating in a random environment
Kim C., Dudin A., Dudin S., Dudina O.
International Journal of Applied Mathematics and Computer Science
|
2014
|
Vol. 24, no. 3
485--501
EN
A multi-server queueing system with two types of customers and an infinite buffer operating in a random environment as a model of a contact center is investigated. The arrival flow of customers is described by a marked Markovian arrival process. Type 1 customers have a non-preemptive priority over type 2 customers and can leave the buffer due to a lack of service. The service times of different type customers have a phase-type distribution with different parameters. To facilitate the investigation of the system we use a generalized phase-type service time distribution. The criterion of ergodicity for a multi-dimensional Markov chain describing the behavior of the system and the algorithm for computation of its steady-state distribution are outlined. Some key performance measures are calculated. The Laplace–Stieltjes transforms of the sojourn and waiting time distributions of priority and non-priority customers are derived. A numerical example illustrating the importance of taking into account the correlation in the arrival process is presented.
16
Content available Analysis of an M|G|1|R queue with batch arrivals and two hysteretic overload control policies
Gaidamaka Y., Pechinkin A., Razumchik R., Samouylov K., Sopin E.
International Journal of Applied Mathematics and Computer Science
|
2014
|
Vol. 24, no. 3
519--534
EN
Hysteretic control of arrivals is one of the most easy-to-implement and effective solutions of overload problems occurring in SIP-servers. A mathematical model of an SIP server based on the queueing system [...] with batch arrivals and two hysteretic loops is being analyzed. This paper proposes two analytical methods for studying performance characteristics related to the number of customers in the system. Two control policies defined by instants when it is decided to change the system’s mode are considered. The expression for an important performance characteristic of each policy (the mean time between changes in the system mode) is presented. Numerical examples that allow comparison of the efficiency of both policies are given.
17
Content available A finite-buffer queue with a single vacation policy: An analytical study with evolutionary positioning
Woźniak M., Kempa W. M., Gabryel M., Nowicki R. K.
International Journal of Applied Mathematics and Computer Science
|
2014
|
Vol. 24, no. 4
887--900
EN
In this paper, application of an evolutionary strategy to positioning a GI/M/1/N-type finite-buffer queueing system with exhaustive service and a single vacation policy is presented. The examined object is modeled by a conditional joint transform of the first busy period, the first idle time and the number of packets completely served during the first busy period. A mathematical model is defined recursively by means of input distributions. In the paper, an analytical study and numerical experiments are presented. A cost optimization problem is solved using an evolutionary strategy for a class of queueing systems described by exponential and Erlang distributions.
18
Content available remote Determination of loss characteristicsfor queueing systems with bounded buffer space
Tikhonenko O., Tikhonenko-Kędziak A.
Studia i Materiały / Europejska Uczelnia Informatyczno-Ekonomiczna w Warszawie
|
2013
|
Nr 2(6)
29--38
EN
We investigate non-classical queueing systems with demands characterized by some random capacity under assumption that demand service time generally depends on its capacity. This dependency can be defined by the joint distribution function. The total demands capacity (i.e. the sum of capacities of demands present in the system at arbitrary time instant) is bounded by some constant value V that is named buffer space volume of the system. Such systems have been used to model and solve various problems occurring in the design of computer and communicating systems. The main steady-state performance characteristics of such systems are loss probability (the relative part of demands that was lost in the system during infinite time interval) and probability of capacity unit losing (the relative part of total demands capacity that was lost during infinite time interval). In the paper we determine these characteristics for some systems with bounded buffer space and compare the results of our calculations with the results of calculations of loss probability in classical regenerative queueing systems using the relation obtained in [3]. Numerical examples and results of simulation are attached as well.
PL
W artykule zbadano nieklasyczne systemy kolejkowe, w których zgłoszenia są charakteryzowane losową objętością przy założeniu, że czas obsługi zgłoszenia ogólnie zależy od jego objętości. Wskazana zależność może być określona za pomocą wspólnej dystrybuanty. Objętość sumaryczna (tj. suma objętości zgłoszeń obecnych w systemie w dowolnej chwili czasu) jest ograniczona wielkością stałą V, którą nazywamy pojemnością pamięci systemu. Systemy podobnego typu są wykorzystywane do rozwiązywania rożnych zagadnień w trakcie projektowania systemów komputerowych i sieci komunikacyjnych. Podstawowymi charakterystykami wydajności takich systemów w trybie stacjonarnym są prawdopodobieństwo utraty (część względna utraconych zgłoszeń w ciągu nieskończonego przedziału czasowego działania systemu) oraz prawdopodobieństwo utraty jednostki objętości (część względna utraconej sumarycznej objętości zgłoszeń w ciągu nieskończonego przedziału czasowego działania systemu). W artykule przedstawiono sposób obliczania wskazanych charakterystyk dla pewnych systemów kolejkowych z ograniczoną pojemnością pamięci oraz porównanie otrzymanych wielkości prawdopodobieństwa utraty z wynikami podobnych obliczeń otrzymanych w [3] dla klasycznych systemów kolejkowych o zachowaniu opisywanym procesem regenerującym się. Podano także wyniki obliczeń numerycznych i symulacji komputerowej.
19
Content available Queueing system M/M/n/(m, V ) with non-identical servers
Małek J., Ziółkowski M.
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics
|
2013
|
Vol. 18
29--39
EN
We investigate multi-server queueing systems with Poisson arrivals, non-identical servers and customers of random volume, under assumption that customer’s service time having an exponential distribution doesn’t depend on his volume, but service time parameters can be different for different servers. We also assume that the total volume of customers present in the system at arbitrary time instant is bounded by some constant value V > 0. For such systems the stationary customers number distribution and loss probability are determined.
20
Content available remote Analysis of AQM queues with queue size based packet dropping
Chydziński A., Chróst Ł.
International Journal of Applied Mathematics and Computer Science
|
2011
|
Vol. 21, no 3
567-577
EN
Queueing systems in which an arriving job is blocked and lost with a probability that depends on the queue size are studied. The study is motivated by the popularity of Active Queue Management (AQM) algorithms proposed for packet queueing in Internet routers. AQM algorithms often exploit the idea of queue-size based packet dropping. The main results include analytical solutions for queue size distribution, loss ratio and throughput. The analytical results are illustrated via numerical examples that include some commonly used blocking probabilities (dropping functions).
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.