Customer Applications of Vensim
Vensim can be used to solve a variety of problems. There are a
number example applications at our
corporate web site, in the literature,
and of course in the models that come with Vensim. Still, that is
only a small sample of the things that can be done.
Here are some of the areas in which our customers and partners have applied
Vensim. If you have an interesting application you would like to
share, please send us a
note.
C-ROADS and C-LEARN are interactive, accessible computer
simulations that help people visualize the long-term climate impacts of
decisions being undertaken today. By making it easy to add up country
emissions targets and to project their implications for the "bathtub
dynamics" of the atmosphere, they bring accountability to the global
negotiation process. C-ROADS has a number of high profile users,
including the US State Department. You can run
C-LEARN online.
Senator John Kerry Introduces C-ROADS Climate Simulator from Climate Interactive on Vimeo.
The rich C-ROADS interface is powered by Ventana
UK's Sable, which provides access to all of Vensim's high-end
features, including sensitivity analysis (used for assessment of the
effect of uncertainty about climate sensitivity and business-as-usual
emissions), dataflow between models (for attribution of temperature
outcomes to regional emissions), and Excel input and output.
Vensim is one of the most popular ways to create models for web deployment
at Forio ...
LNG Plant Design, Scott Johnson, BP
For analytic work in support of capital investment decisions
the ultimate measure of success is not always clear. Plants and
distribution systems that perform as expected in terms of throughput
and uptime do validate the results of technical components of the
simulation. Making such comparisons in detail is, however, costly and
time consuming. In addition, changes in market and business conditions
tend to have a very large impact on the economic value of
infrastructure and the uncertainty around those is extremely high.
Many capital investment decisions are addressed using detailed discrete
event simulations. Continuously formulated Vensim models can be
used to address the same issues and offer some improved
transparency. We developed a model to look at reliability and
maintainability of a Liquid Natural Gas (LNG) plant using different
assumptions on sizing and configuration. While this model was not
that much different conceptually from its discrete event counterparts,
Vensim does have some advantages for presentation and analysis and we
believe this is a
worthwhile approach to developing models in support of investment
decisions. More information on this is available in a paper presented
at the 2002 System Dynamics Conference, and the model is also
available.
Experimental Aerodynamics, Lucas
Laroche, Laroche Consulting
In order to measure performance of aircraft wings it is
necessary to have both a physical model of the wing and the
experimental results showing wing performance. Vensim's
optimization and data handling capabilities were used to measure the
lift to drag ratio as a function of velocity. The control line
airplane's movement is determined by the rotating velocity w and the
inclination angle a. Thrust (equals drag) is measured at the
engine of the airplane using Hooke's law. A Vensim model was used
to estimate the underlying parameters, quickly and efficiently, in
order to explore design alternatives.
For more on the results of this work see http://www.winggrid.ch.
Shock Analysis and Testing, Michael
Talley
A new,
efficient, easy to use 6 degree of freedom (6DOF) simulation
method called Shock Isolation Mount Predictions & Loading Estimates
(SIMPLE) has been developed and its use evaluated. SIMPLE
specifically addresses the need for practicality and efficiency by
providing: 1) estimates of the excursion space needed for dynamic
travel of mounted systems; 2) rapid prediction of responses such as
acceleration, velocity, force, displacement, etc.; 3) a design tool for
the location, sizing, and orientation of mounts for equipment and
structures; 4) calibration via optimization; 5) multivariate
sensitivity analyses of system parameters; 6) a shock mount library of
more than 250 mounts; 7) inputs from floating shock platforms, deck
simulators; medium weight shock test machines, etc.; and 8) immediate
presentation of data after simulation. SIMPLE uses systems
dynamics programming to integrate causal relations into feedback loops
so that system behaviors such as growth, decay, oscillations, etc. can
be examined. Shock isolated systems are characterized as 2nd
order feedback loops in the SIMPLE program. A systems dynamics
simulation environment called Vensim by Ventana Systems, Inc provides
the workbench for programming the causal relations as well as the
simulation and outputs necessary to examine behavior.
No special knowledge is required to use
the new simulation method and no overcomplicated modeling assumptions
are necessary to obtain reasonable estimates of isolated system
responses. For example, most 6DOF analysis tools such as finite
element codes and specialized simulation tools require an extensive
working knowledge and expertise to build and simulate models for shock
isolated systems. Calibrating and implementing multivariate and
univarite sensitivity analyses with such tools would be even more
complicated and time consuming.
More
information on SIMPLE is available at http://webpages.charter.net/michael.talley
Tracking
Team Skills, Peter Addor
In order to
track the ability of a team to do its work it is necessary to know both
how much skill the team has built up as a team and what the experience
levels of the individual team members are. By creating a matrix
of team membership that includes both time with the team and individual
experience levels it is possible to do this. Using a fairly large
array and the tricky SHIFT IF TRUE function it is possible to track
team skills and their individual components with any desired degree of
precision.
Positive
Feedback,
Bob
Walker
Bob Walker
discovered yet another use for Vensim - naming his boat. He
created the graphic with the name and feedback loop and then had the
sign company transfer that to the back of his new boat. The
result floats above the rest.
|
