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

Znaleziono wyników: 11

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  queuing systems
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Simulation modeling in GPSS for optimizing the traffic lights cycle of adjustable crossroads
Kravchenya Irina, Lebid Iryna
Journal of Sustainable Development of Transport and Logistics
|
2020
|
Vol. 5, No. 1
48--55
EN
The problem of traffic management, especially in big cities is particularly actual. Due to unavoidable motorization increase in number of vehicles has resulted in congestion, traffic jams, difficulty of the movement of pedestrians, increasing the number of accidents. Traffic jams are undesirable because of higher fuel consumption, increased pollution due to exhaust gases as well as noise, etc. The only way to avoid harmful consequences is to optimize the operation of the traffic lights cycle. The purpose of the work is creation the simulation model in GPSS for determining the optimal traffic lights cycle at adjustable crossroads when managing vehicle flows with specified intensities. The mathematical model of adjustable crossroads can be presented as a queuing system. Development of the simulation model includes several stages: programming in GPSS, verification and assessment of the adequacy. The algorithm for optimizing the traffic lights cycle and diagrams are used to find the optimal value of the cycle. The minimum intersection travel time (including time of queuing) is selected as the optimal criterion. The object of study is the traffic lights cycle regulation of the intersection Sovietskaya St. – Rogachevskaya St. – Telman St. in Gomel, Belarus. The existing traffic lights cycle regulation at the intersection Sovietskaya str. – Rogachevskaya str. – Telman str. has been studied. Simulation modeling of the intersection has been created in GPSS and traffic light cycle optimization algorithm has been developed. According to a worked out algorithm the traffic lights cycle at research intersection during saturation flux has been improved. Transport delays both at the existing and optimized crossings have been estimated. Optimization of the traffic lights cycle will increase the traffic capacity of the intersection, reduce the volume of toxic emissions and decrease the accident risk. The developed simulation model can be modified for other types of intersections and used as the basis for a decision support system based on low-level simulation.
2
Badania symulacyjne systemów kolejkowych z niepełnodostępnym serwerem
Hanczewski S., Weissenberg M.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2018
|
nr 8-9
654--659, CD
PL
W artykule przedstawione zostały rezultaty badań symulacyjnych wielousługowych systemów kolejkowych z niepełnodostępnym serwerem i różnymi dyscyplinami obsługi kolejek. W przeprowadzonych badaniach wykorzystany został autorski symulator. Implementacja symulatora zakończyła pierwszy etap badań nad systemami kolejkowymi z niepełnodostępnym serwerem. W następnych etapach, autorzy podejmą próbę opracowania modeli analitycznych takich systemów kolejkowych a opracowany symulator pozwoli na ich weryfikację.
EN
This paper presents the results of a simulation study of a number of multi-service queuing systems with a non-full- availability server and different queue service disciplines. The simulator used in this study was designed and developed by the authors. The implementation of the simulator completed the first stage of the study on queueing systems with non-full-availability server. Further stages of the study will involve attempts to develop appropriate analytical models of these queuing systems, while the already developed simulator will make their verification possible.
3
Content available On characteristics of the Mθ/G/1/m and Mθ/G/1 queues with queue-size based packet dropping
Zhernovyi Y., Kopytko B., Zhernovyi K.
Journal of Applied Mathematics and Computational Mechanics
|
2014
|
Vol. 13, nr 4
163--175
EN
We study the Mθ/G/1/m and Mθ/G/1 queuing systems with the function of the random dropping of customers used to ensure the required characteristics of the system. Each arriving packet of customers can be rejected with a probability defined depending on the queue length at the service beginning of each customer. The Laplace transform for the distribution of the number of customers in the system on the busy period is found, the mean duration of the busy period is determined, and formulas for the stationary distribution of the number of customers in the system are derived via the approach based on the idea of Korolyuk’s potential method. The obtained results are verified with the help of a simulation model constructed with the assistance of GPSS World tools.
4
Content available remote Analysis of networks with time-dependent transition probabilities and messages bypass between the queuing systems
Matalytski M., Naumenko V.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2012
|
Vol. 11, nr 4
93-104
EN
The object of investigation is an open exponential network with a messages bypass of systems in transient behavior. The purpose of the research is to find stationary probabilities of states and the average characteristics of the network when the transition probabilities between the messages and bypass systems of the network, parameters of the incoming flow of messages and services are time-dependent. To find the state probabilities and the characteristics of a network is used the apparatus for the multivariate generating functions. The examples are calculated on a computer.
5
Content available remote Dobór liczby ankieterów w badaniach na kordonie drogowym
Rudnicki A.
Zeszyty Naukowo-Techniczne Stowarzyszenia Inżynierów i Techników Komunikacji w Krakowie. Seria: Materiały Konferencyjne
|
2010
|
Nr 93, z. 152
139-152
PL
Artykuł bazuje na doświadczeniach z przeprowadzonych w Krakowie kordowych badań ruchu na drogach. Określono cele, szczegółowe zadania badania ankietowego oraz zakres jego wykorzystania. Dokonano fizycznej oraz matematycznej identyfikacji systemów obsługi masowej (w tym ich elementów) w procesie ankietowania kierowców pojazdów. Posługując się metodami analitycznymi i symulacyjnymi przebadano przypadek systemu obsługi masowej z kolejką, jako typowy dla małych natężeń ruchu pojazdów. Następnie rozważono przypadek systemu obsługi masowej bez kolejki (ze stratą zgłoszenia) jako typowy dla średnich i dużych natężeń ruchu. Wyniki rozważań pozwalają oszacować liczbę potrzebnych ankieterów oraz przepustowość stanowisk ankietowania.
EN
The paper founds on the experiences of road interviews which were performed at the road gates in Krakow. Aims, detailed tasks and range of applications for road interviews have been determined. For the interview process of drivers, the physical and mathematical identification of queuing system and its elements have been made. Using both, analytical and simulation methods, the cases of the systems with queue and without queue are investigated. The first case is typical for low traffic volume, the second one for medium sized and high traffic volume. The results allow to estimate the number of needed inquirers and the capacity of surveys points.
6
Content available remote Ontological Model of the Conceptual Scheme Formation for Queuing System
Kusztina E., Różewski P., Zaikin O.
Management and Production Engineering Review
|
2010
|
Vol. 1, No. 1
85-97
EN
In the article the authors propose an extended ontological model for distance learning, concerning pedagogical and cognitive requirements of the teaching/learning process. The main characteristic of the dedicated ontological model is reusability, which manifests itself in the possibility of adapting the knowledge model to different contexts and for different users by simply enabling knowledge sharing and knowledge management. The conceptual schemes are used for modelling the knowledge about queuing systems for knowledge repository and ontology development purposes. Authors have taken advantage of the computational models theory in order to create a model which combine theoretical and procedural knowledge.
7
Content available remote Construction of queue-based simulators for web applications distributed on computer networks
Pasini L., Feliziani S.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2005
|
Vol. 9, No 4
373-396
EN
Modern Internet and web applications involve interactions among remote host computers connected by communication networks. Simulation modelling is an important technique to evaluate performance in the implementation of a web-distributed application over given networks formed by computer hosts connected by heterogeneous networks. In this paper we extend a previous work concerning the construction of a queue-based simulator of communication networks. We define a set of new queue-based object types which permit us to specify the behaviour of a web-distributed application whose software components run over different hosts in a given communication network. We apply this technique to show how to build a simulator to evaluate the performance of various software architectures for a web-distributed application run over a given computer network.
8
Content available remote A method to build network-of-queues-based simulators for communication systems
Pasini L., Feliziani S.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2004
|
Vol. 8, No 3
333-358
EN
In this study we build a library of new object types whose architecture is based on models of networks-of-queues to simulate communication networks. We also define a class of procedures to automatically generate a simulator of a generic communication network described by the library's objects.
9
Content available Analytical properties of a stochastic teletraffic system with MMPP input and an access function
Tralhao L., Craveirinha J., Cardoso D.
Journal of Telecommunications and Information Technology
|
2002
|
nr 3
17-23
EN
Stochastic modeling of teletraffic systems with restricted availability and correlated input arrival rates is of great interest in GoS (grade of service) analysis and design of certain telecommunication networks. This paper presents some analytical properties of a recursive nature, associated with the infinitesimal generator of the Markov process which describes the state of a teletraffic system with MMPP (Markov modulated Poisson process) input traffic, negative exponentially distributed service times, finite queue and restricted availability defined through a loss function. Also the possible application of the derived properties to a direct method of resolution of the linear system, which gives the stationary probability distribution of the system, will be discussed.
10
New priority scheme for differentiating QOS in IP networks
Burakowski W., Tarasiuk H.
Archiwum Informatyki Teoretycznej i Stosowanej
|
2001
|
T. 13, z. 3
231-247
EN
The paper describes a new multi-level priority scheme for differentiating quality of traffic handling in IP networks, like TCP and UDP. The investigated scheme is based on the Queue Management Algorithm with Reservations (QMAR) and assumes that each arriying packet from a prioritised flow reserves a specified place in the current queue for the next packet of this flow. The reserved place is moving up to the top of the queue according to the system service process. This mechanism guarantees that a packet (from the prioritised flow) entering the system seizes its reserved place, not necessary the last one in the queue. As a consequence, the waiting times of packets from the prioritised flow depend on temporary arrival rate strictly. Furthermore, the investigated scheme avoids service degradation of lower priority packets that is obseryed in the case of pure priority scheme (e.g. with non-preemptive resume ). In the paper, the considered system is analysed in terms of Poissonian input process and negative exponential packet service times. Appropriate formulas for mean waiting times of packets belonging to particular flows arę derived. Furthermore, the features of the proposed scheme are outlined, and compared to the system with and without priorities. The examples of application of the proposed scheme to differentiate packet transfer quality for TCP and UDP traffic are also included.
PL
Artykuł opisuje nowy, wielopriorytetowy schemat różnicowania jakości usług w sieciach z protokołem IP, takich jak TCP i UDP. Zastosowane podejście jest oparte na Algorytmie Zarządzania Kolejką z Rezerwacjami QMAR i zakłada, że każdy z pakietów przychodzących w wielopriorytetowym strumieniu rezerwuje w kolejce miejsce dla następnego pakietu z tego strumienia. Czas oczekiwania na obsługę pakietu z danego strumienia zależy całkowicie od chwilowej intensywności strumieni. Ponadto badany schemat nie powoduje degradacji obsługi pakietów o niższym priorytecie, którą można zaobserwować w przypadku klasycznych kolejek. Artykuł analizuje rozważany system przy założeniu poissonowskiego procesu nadejść i wykładniczego czasu obsługi pakietów. Cechy zaproponowanego regulaminu kolejkowego są porównywane z systemami priorytetowym i bez priorytetów. Załączono również przykłady zastosowania zaproponowanego regulaminu rozróżniania jakości przesyłu pakietów dla ruchu TCP i UDP.
11
Content available remote Analiza systemów kolejkowych metodą badania procesów półmarkowskich
Szostek R.
Elektrotechnika i Elektronika
|
1999
|
T. 18, z. 4
137--145
PL
W pracy zostały przedstawione przykłady zastosowania procesów półmarkowskich do analizy systemów kolejkowych. Metody badania markowskich procesów mogą okazać się niewystarczające dla uzyskania dokładnych ilościowych oszacowań parametrów systemów, w których pewne rzeczywiste rozkłady różnią się od wykładniczych. Dla wielu systemów kolejkowych udaje się znaleźć parametry obsługi w stanie ustalonym dzięki wykorzystaniu metody badania procesów półmarkowskich
EN
In this work there are some examples of applying quasi Marków processes to analyse ą\queuing systems. Methods of studies Marków 's processes would be not good enough to achieve accurate quantitative evolution of systems parameters in which same real distribution are different to stationary state using studies of quasi Marków processes
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.