What is scheduling
Assigning an appropriate no of workers to the job
during each day of work.
1. Determining when an activity should start and end,
depend on its :
• Predecessor activity (or activities )
• Predecessor relationship
• Resource availability
• Target completion date of the project
In Production scheduling
Companies use forward and Backward scheduling .
• Forward Scheduling
• Backward Scheduling
Objectives of Scheduling
OTHER RESOURCE USE :
Other Scheduling objectives:
Fairness to all processes
Balance available resources
Enforcement of priorities
Achieve balance between response and utilisation
Avoid indefinite postponement and starvation
Favour processes exhibiting desirable behaviour
Degrade gracefully under heavy load.
There are three main Scheduling
Long-term Scheduling -The long-term scheduling
controls the degree of multiprogramming and decides on
which job or jobs to accept and turn into processes.
Medium-term scheduling-which determines
which processes suspended and resumed?”
Short-term Scheduling: Short term scheduling is
concerned with the allocation of processor time to
processes in order to meet some pre-defined system
Scheduling Levels :
High level Scheduler (External priority) is
responsible for deciding which job currently on disc
are to be brought into memory.
Low Level Scheduler (Internal Priority) is
responsible for deciding which of the ready
processes is to be run.
B E S T
(Brihanmumbai Electric Supply and Transport)
BEST bus started in the year 1907.
Total 4680 busses.
25 depots (region wise).
22000 bus drivers and conductors.
It is considered a second heart of the city.
1. Placement of the Bus Route.
Route In New Area .
proper route placementThe route creation process .
Identify an area that needs new transit service
Determine the terminus locations
Designing the route include the presence of other routes nearby and
the type of street the bus will travel upon. Except in very dense
areas, parallel bus routes should be no closer than 1/2 mile to each other.
Speed bumps, speed humps, or traffic circles should also be avoided.
B. Route In Existing Area.
Plan new bus routes operating in areas with
These new routes are often have limited stop
or express versions of existing local routes.
Provide direct service between two trip
Service levels increase.
c. Placement of Bus Stops
Appropriate distance between each bus stop.
Placement of bus stops -the presence of trip
generators, transfer opportunities with other routes,
and pedestrian access.
Adopting guidelines which allow for wider stop
spacing offers several advantages to the transit
Site visit to determine the actual placement at the
Bus stops should be located at traffic signals, or at
least marked crosswalks
D. Determination of Times for the Bus
Each route will at the very least have two
timing points: the start and end of the route.
Optimum number of time points be
selected for the route. For that
1. Estimate running time.
2. Calculate the overall cycle time can be
determined.(Before and After )
E. Writing the Bus Schedule
What our stops are.
How long it will take to travel between our
1. Using computer scheduling software .
The most important benefit of scheduling
software lies in its run cutting function.
2. For scheduling a particular route two
things are important.
The service span of the route .
For existing route – we would consider a demand
based service span based on the first and last
If no body was riding-reduce the service
If a significant no. of people were riding-50 %
or more-consider the service span.
3. Policy based service span and the run
Policy based service span- specific time
The run cutting process- make it easier and
more cost effective to schedule the drivers
The frequency/headway of the route.
1. Demand based headway.
How often buses will pass by a particular
point along the route.
Minimum number of buses required per hour.
Load factor- maximum number of
passengers per bus, every seat is full no body
is standing-i.e. in the ratio of 1.0 .
2. Policy based headway.
Operate a minimal level of service.
All of their routes operate at least every
thirty minutes whenever the subway is in
From 4.30 AM to 2 AM Monday through
From 6 AM to 2 AM on Sunday.
Once the determination of service span and
the headway the actual creation of the
schedule is quite straightforward.
By using scheduling software .
F. Blocking, Run Cutting and Rostering.
Cutting the schedule.
Blocking the trips.
If the block operates out of closest depotsaves deadline time and money.