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Information flows drive different physical flows. The stock and flow diagram for
the sales system discussed earlier is shown in” (Gambar 2.5).
Gambar 2.5 Stock and flow diagram for sales system
Taylor & Francis (2009)
The
arrows
drawn
with
regulating
valves
indicate physical
flows.
Rectangles
(Order
Backlog,
Sales
Staff) indicate
accumulations
or
stocks.
The
valves (Order
Bookings,
Deliveries,
Hiring) on the physical flows control flows
in and out of stock. In system dynamics parlance they are termed as flow
variables. Circles (Budget Allotted for Sales Force) indicate converters that are
used to capture decision rules or perform intermediate computation. Thin arrows
represent information flows connecting converters with stocks.
The stock and flow structure of the system is simply shorthand for the
underlying mathematical representation of the system. Each
stock is an
integration of flows affecting
it. For the purpose of simulation this
is expressed
as a difference equation wherein over a time period "dt," the value of stock
changes
by
"dt"
times
the
net
flow
into
the
stock.
A
flow
is
expressed
as
a
function
of
one
or
more
stocks
and
converters.
Each
converter
represents
the
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