Lecture 5 - Queuing Theory Flashcards
One of the major issues in the analysis of any traffic system is the
_________
analysis of
delay
_____ is the difference between the actual travel time on a given
segment and some ideal travel time of that segment
.
Delay
In practice, the
________
chosen will depend on the
situation; in general, however, there are two particular travel
times that seem best suited as benchmarks for comparison with
the actual performance of the system. These are
the travel time
under free flow conditions
and
travel time at capacity
ideal travel time
the rate at which vehicles arrive at a
service facility
Mean arrival rate
the rate at which vehicles depart from
a service facility:
Mean departure rate
that are
being utilized that influences formation of a queue.
number of servers or stations
parameter that explains how the vehicles arrive
at a service facility.
Queue discipline
There are 5 types of queue disciplines:
First in, first out (FIFO) •First in, last out (FILO) •Served in random order (SIRO) •Priority scheduling •Processor/time sharing
If the vehicles are
served in the order
of their arriva
First in, first out
If the vehicles are serviced in the reverse order of their entry, so that the ones who join the last are served first.
First in, last out
Under this rule customers are selected for service at random, irrespective of their arrivals in the service system
Served in random
order
Under this rule customers are grouped in priority classes on the basis of some attributes such as service time or urgency or according to some identifiable characteristic, and FIFO rule is used within each class to provide service.
Priority service
• The server is switched between all the queues for a predefined slice of time (quantum time) in a round - robin manne
Processor/time
sharing
