Announcements including Conferences, Workshops, Job Openings, Software, and News Items. All announcements are moderated. To open discussion on an announcement use the discussion forums.

VisualAivika 5 released

Postby David Sorokin » Sat Nov 14, 2015 1:12 am


I'm glad to announce the release of VisualAivika 5. This is a visual simulation software tool for System Dynamics and Systems Thinking. It works on Microsoft Windows and requires .NET Framework 4.5 or higher (.NET 4.5 is pre-installed on Windows 8 and 8.1, but can be installed on Windows Vista and Windows 7).

There is an easy-to-use diagram editor that allows creating nice looking Casual Loop Diagrams (CLD) as well as Stock and Flow Maps (SFM). There is also a simulation component that supports its own high-level modeling language. There is the equation editor, where you can define integrals, arrays, random functions. Moreover, VisualAivika supports the Monte-Carlo simulation, which allows providing Sensitivity Analysis. There are means for plotting charts on the diagram to show the results of simulation in a form of Time Series, XY Chart and Deviation Chart. The results can be exported.

There are four editions of VisualAivika:

- VisualAivika PLE is a personal learning edition. It is free for non-commercial use only and can be used for evaluation. Please note that it supports arrays and the Monte-Carlo simulation;

- VisualAivika Draw is a light-weight version with the diagram editor for CLD and SFM;

- VisualAivika Basic allows doing what VisualAivika PLE can, but it can be used for commercial projects;

- VisualAivika Professional is a full edition that has no restrictions. Moreover, the partial simulation is supported for creating large-size models.

Best regards,
David Sorokin
David Sorokin
Posts: 5
Joined: Tue Sep 15, 2009 4:13 am

Powersim AS announces Studio 10 Feature Pack 1

Postby Leonard Malczynski » Mon Aug 10, 2015 9:49 am

Powersim Studio announces Feature Pack 1 for Studio 10
New features are:
- Custom Functions - high-performance, user-defined functions in C++
- Support for JPEG, PNG, GIIF and TIFF picture formats

Please go to: for details
Leonard Malczynski
Posts: 88
Joined: Fri Jan 16, 2009 11:12 am
Location: Albuquerque, NM USA

Re: Software

Postby Kim Warren » Thu Jul 16, 2015 7:00 am

Strategy Dynamics Ltd is pleased to announce a substantial upgrade and relaunch of the Sysdea modeling software.

... and is free until end-September [then still free for registered Teachers]. (These items are being continually extended - so revisit for the latest set)

Sysdea has been rebuilt from the ground up to be super-easy and fast to use, and it's live running with actual-v-simulated time-series, explicit behaviour-charts and auto-complete make it very hard to make mistakes. This makes Sysdea ideal ...

    ... for teaching - where newcomers can be building understandable models in minutes and instant, slick model-sharing cuts teaching delays to nothing

    ... for building reliable, real-world models fast - yes, you can build working, quantified models showing crystal-clear, live, model-wide dynamic results with teams in real time.
New Sysdea has already been used "in anger" to model complex multi-competitor dynamics for a pharmaceuticals product launch and to build business plans in a couple of days for fast-growth companies to raise large sums of cash - to quote one big investor "I had no idea this kind of live business modeling was even conceivable, let alone do-able!"

This browser-based app is not only quick and easy to use - it is also super-fast to run ... and can be installed inside corporate firewalls to deal with security issues. Further Pro-level features are in progress.

We look forward to showing Sysdea at next week's conference, where we are running these events ...

    Monday 20 July: 1.30 ... our Exhibitor Demonstration in the Crispus Attucks room - key features and benefits, plus discussion of Teachers' needs (We want the software easily accessible, and plan affordable Institutional accounts in which Teachers can set up classes with no need for students to install or register, share models and assignments).

    Thursday 23 July 10.30 ... in the Haym Solomon room, for Getting Started with Sysdea.

    Friday 24 July 13.00 ... in the Paul Revere room, for Agile SD - Fast, Reliable, Effective
Kim Warren
Posts: 110
Joined: Mon Feb 16, 2009 5:56 am

Insight Maker 5 Released

Postby Scott Fortmann-Roe » Sat Jun 14, 2014 2:59 pm

I am pleased to announce the release of Insight Maker version 5 (!

This release includes many new features which we are incredibly excited about. Insight Maker is a web-based, multi-paradigm modeling platform that integrates System Dynamics and Agent Based Modeling techniques. It includes a range of powerful tools for optimization and parameter estimation, sensitivity testing, automation, scripting, and storytelling.

Here are some of the great new features added in this release:

  • A Stunning New Look: Insight Maker now has a beautiful new theme. In addition to looking great, this theme makes it easier for us to extend Insight Maker with new features in the future.
  • Flight Simulators and Interactive Models: Insight Maker now supports interactivity during simulations. You can specify a time interval at which the simulation will be paused or trigger a pause on-the-fly. This enables the creation of interactive "flight simulators" along with games for experimentation and learning.
  • Great Mobile Support: You could always run Insight Maker on your iPad or other tablet, but in this release we have worked hard on providing even better support for these platforms. Every element in the Insight Maker interface has been adjusted and tweaked to work great with finger-based input. We've also added a new equation keyboard that only appears on mobile devices to make it easy to enter equations.
  • Enhanced Agent Based Modeling: Insight Maker's Agent Based Modeling tools have been greatly enhanced. Amongst many other improvements, agents now operate in continuous time. This means that events will occur precisely when you schedule them, instead of at a pace determined by the differential equation solver. This enables better performance and more accurate simulations.
  • And Much More: Diagram image export, experimental XMILE import support, new diagramming features such as line weights, and a new loading screen. These are just some of the other new features added to Insight Maker as part of version 5.

You can learn more about these features release by watching the video overview (

You can give Insight Maker a try at It is a 100% free and open-source platform.

Scott Fortmann-Roe
Posts: 37
Joined: Sun Mar 08, 2009 5:16 am
Location: Krakow, Poland; Berkeley, California

Vensim 6.3 released

Postby Thomas Fiddaman » Tue Jun 10, 2014 2:16 pm

Vensim 6.3 is available for download or purchase in the Vensim Store.

See for details and downloads, including the free PLE and Model Reader.

6.3 emphasizes engine improvements that keep Vensim #1 when it comes to industrial strength simulation:

Random Numbers & Sampling
A new pseudorandom number generator, extensively tested with the Statistical Test Suite from the National Institute of Standards – great for financial, stochastic or statistical models that are heavy consumers of random numbers.
Optimization and sensitivity control files may now specify a random seed of 0 to trigger randomization to system cryptographic sources (useful for performing independent runs on multiple computers without editing the control files).
Improved sampling for Sensitivity (Monte Carlo) Simulations.
Big improvements to Markov Chain Monte Carlo and Simulated Annealing performance
A broader distribution of initial test points in random multistart optimization (MWYS), to find optimal solutions faster (up to 100x in one test case).
Improved speed in stochastic optimization, with support for the File sensitivity control option.

There are also some usability upgrades, like better number formatting and placement of the workbench variable in the bottom status toolbar.

Vensim 64

A 64-bit beta version is available for download to Vensim Pro and DSS users who are current with their maintenance. It’s full-featured and supports huge models.

Vensim 6

If you’re not current with Vensim 6, there are some valuable new features, including:

Native Mac support (licenses are portable across platforms)
GET DIRECT functions that can access spreadsheets and other delimited data files, like the GET XLS functions without the overhead of launching Excel.
Significant upgrades to the Help system, including improved indexing and nearly 100 sample models illustrating the use of almost every built-in function
A new Equation Editor
Improved Toolbars and Cursors
The option of observing integer constraints in the ALLOCATE AVAILABLE function – great for managing allocation of discrete items like customers or aircraft.
On-the-fly configuration of subscripts (arrays) with the GET DIRECT SUBSCRIPTS or GET ODBC SUBSCRIPTS functions – great for matching model detail to your data.
:EXCEPT: statements that let you handle exceptions to subscripted equations more easily.
Optimization features
Stochastic optimization : optimize over an ensemble of Monte Carlo simulations
Discrete constraints on optimization parameters, so you don’t waste time determining whether to build 2.6 or 2.7 factories.
Extended payoffs with non-Gaussian errors, logarithms, and mixed calibration/policy variables.
Markov chain Monte Carlo & simulated annealing
Extended payoff report information with MAPE and Theil statistics

Feedback from our users who’ve upgraded to version 6 has been highly positive. Contact us for details on any of these.

The Next Great Thing

This summer, we will be showing an exciting new product that will help you build better models of complex systems.

Key benefits are:

• Hierarchy and object orientation, supporting sectors and complex agents, with no arcane arrays

• Dynamic creation and deletion of model components and relationships

• Support for team collaboration, model federation and submodels

• Advanced graphics and a new, clean look

• Just like Vensim, a pure declarative language (no programming)

Please stop by and visit us at the Ventana/Greenwood table during the System Dynamics conference. Or, come to the Vensim user’s group meeting and our Thursday workshops on Vensim and building entity-based system dynamics models. We look forward to seeing you in Delft!
Thomas Fiddaman
Posts: 149
Joined: Thu Jan 15, 2009 6:55 pm
Location: Bozeman, MT

True 2014.04.26 release

Postby Patrick Houel » Sun Apr 27, 2014 4:21 am

True (Temporal Reasoning Universal Elaboration)
Free of charge system dynamics software

- Dynamic 3D model display


- Frames and boxes(opaque recursive frames): when resizing, inside elements are moved

- 2D model display:
-- zoom between 1% and 999%, with automatic x,y offset: the model stays centered
-- font choice

- Procedure (equation code):
-- parameters: max_c, max_t,... (max cycles, times,...)
-- global variables: array; booleen, currency, integer
-- Windev functions (copyright PcSoft): more than 700 functions:
--- Maths, Finances, Statistics, Files, xls files, Arrays,
--- Strings, Date, Matrix, Memory Areas, Registry, Clipboard, Mouse, Network
--- Http, Ftp, Socket, Serial and parallel port, Event, SQL, Hyperfile

- Remote compute option:
-- if enable, this option allows to start compute if the 'Remote.ini' file is in the export directory

- Ten exercices
- Examples: WorkingWith... models

Technical support
Patrick Houel
Posts: 3
Joined: Thu Dec 10, 2009 6:36 am

Powersim Studio 10 released

Postby Leonard Malczynski » Wed Apr 09, 2014 10:00 am

Powersim AS has released Powersim Studio 10 (
There are many new features and improvements. A more thorough list can be found at the website.

-free Studio Cockpit model distribution
-expanded connections to file-based databases
-a new method CreateActiveXObject for the external object available to the HTML document contained in Presentation Sidekicks and in the dialog of Show Dialog actions.
-a new method Simulation::SetMultipleValues in the Simulation Engine Object Model that makes it possible to change the value and/or history of multiple variables
-a new function PERIODLENGTHSERIES that returns the length of all series periods as a vector.
-revamped the password protection scheme
-introduced an option named 'Enable Active Content'
-possibility to limit the number of cores utilized for calculations per simulation project.
-the Oil Production Simulation sample has been updated to use the CreateActiveXObject method
-new sample model: The Upstream Oil and Gas Simulation model illustrates assembly of a model using components from a component library.
-a link to on-line instructional videos in both the Task Assistant and the Help menu.

Len Malczynski
group moderator of the independent Powersim Tools User Group (
Leonard Malczynski
Posts: 88
Joined: Fri Jan 16, 2009 11:12 am
Location: Albuquerque, NM USA

STELLA and iThink 10.0.5 Now Available!

Postby Karim Chichakly » Sun Mar 23, 2014 4:26 pm

isee systems is pleased to announce that STELLA 10.0.5 and iThink 10.0.5 are now available ( This new update runs models faster than ever and also includes minor enhancements to the user interface. A full list of changes to 10.0.5 is available at If you are new to version 10, please visit

To celebrate this improved version of our XMILE-compatible System Dynamics modeling package, we are offering a 20% discount on all upgrades from versions prior to 10.0 and a 15% discount to System Dynamics Society Forum readers on cross-grades from other System Dynamics modeling packages. Please contact us at if you are interested in a quote. Please hurry; this offer ends soon.
Karim Chichakly
Posts: 43
Joined: Fri Apr 10, 2009 11:52 am

Aivika of version 1.1

Postby David Sorokin » Sat Mar 08, 2014 2:40 am

It might be interesting to the modelers who have strong skills in the programming. Here I am glad to announce Aivika of version 1.1.

Aivika [1] is a multi-paradigm simulation library with a strong emphasis on the Discrete Event Simulation (DES) and System Dynamics (SD). It is written in the Haskell programming language. While the support of DES is quite extensive, System Dynamics is well supported too.

So, you can define the recursive stochastic ordinary differential equations (ODEs) almost in the same way as in specialized modeling tools like Vensim. The equations even may look similar.

Here is an example [2] that I took from the documentation of Berkeley-Madonna (the 5-minute tutorial). It returns the integral values in the final simulation time point.

This is the same model [3], only now the calculated data are automatically saved in files and the charts are plotted as well as an HTML page is generated, and all this is fully described in the stated Haskell file. You can observe the results in your favorite Internet browser.

Another example [4] corresponds to the model described in Chapter Financial Modeling Risk of Vensim 5 Modeling Guide. It uses a Monte Carlo simulation that depends on external random parameters. As before, you can observe the simulation results displayed as charts and histograms in your Internet browser. So, the deviation chart is displayed (using the 3 sigma rule).

You can use the Design of Experiment (DoE) as well. There is nothing special with it. Just use functions tableParameter and memoParameter of the Parameter module.

Aivika actually provides an Embedded Domain Specific Language (eDSL). Therefore, you can use all the power of so very high-level and general purpose programming language as Haskell. Aivika makes the latter much more close to the modeling language (there is quite an opposite tendency when other developers are trying to make their modeling language more close to the general purpose one as in SimScript).

The arrays (and more modern vectors) are naturally supported by Haskell itself. There is nothing special too. Only you should be skilled in using so called the recursive do-notation. Namely this notation allows defining the recursive ODEs as in maths.

This model [5] demonstrates the use of arrays as described in model Linear Array from Berkeley-Madonna.

The difference equations are supported too. The model [6] corresponds to the tutorial of Berkeley-Madonna.

A few words about the speed of simulation. The integrating of ODEs is quite slow (about in 15-20 times slower than it could be without combining with DES). At the same time, the DES support is rather fast and namely DES is the main feature of Aivika.

The DES and ODEs can be combined within one model as everything is well integrated in Aivika and uses the same basis, the same mathematical formalism I found.

The integrals can be directly used in the DES model (through function liftDynamics). Now only such integrals are supported that must be calculated in all integration time points, which may lead to consuming much memory and degrading the performance. Therefore; sometimes it makes sense to define the integration method directly in the model as in the Furnace model [11].

An opposite direction from DES to SD is a little more complex. The modeler can use the Var data structure that has a mutable state, usually updated from DES, and that saves the history of its values (only the last change is saved for every time point). Then the Var variable can be used in the differential equations. Please read more details in the documentation of the Var module.

Finally, a few words about DES. Aivika supports very different paradigms of DES from event-driven [7] to activity-oriented [8] to process-driven [9] and even to that one which I invented and which name I do not know yet. It is possible to define the model [10] as a workflow in terms of queues, servers (the working places), infinite streams of data and processors that operate on them. Then the model can be read as you would define it on the diagram. As before, all the DES is well integrated in Aivika (through the event queue).

I’m looking forward to receiving your feedback.

Kind regards,
David Sorokin <>

Yoshkar-Ola, Russia

David Sorokin
Posts: 5
Joined: Tue Sep 15, 2009 4:13 am

Simile v6.1 released

Postby Jasper Taylor » Mon Feb 10, 2014 5:27 am

Simile version 6.1 released

This minor version adds some useful new functionality to Note: a patch release was made on 7th February 2014 correcting a few problems identified after the release.

Much easier to make spatial interaction models

Previously, when using a 2-D array submodel to represent a spatial grid, it was necessary to create a self-association submodel to allow data to be past between instances representing neighbouring grid squares or hexagons. Now there are pre-defined submodel types for these common constructs, inside which you can set link properties to move data between neighbours.

Layered spatial-mapping display tool

There is a new display tool that works a bit like a GIS display, in that representations of several data sets can be superposed on each other in the same window to create composite diagrams. The layers available include rectangular and polygonal maps, and an all-new one for displaying individuals with locations on the maps as icons.

element() function works on lists

The element() function is Simile's way of selecting element(s) from an array or list. Formerly, the first argument of element() had to be an array, because values had to be looked up directly by their indices. Now the first argument can be a list (a value from a variable-membership submodel such as a population) and the result is a sublist, generated by seeking through the list and adding all the values whose indices appear in the second argument.

element() function takes multiple indices

If you have a 2-D (or higher) array, you can look up a single member by using element() with 3 (or more) arguments, e.g.,

Code: Select all
element([[arr]], x, y)

Formerly you would have had to do this by nesting element() calls, but the new format is neater and allows the indices to be matching arrays or lists themselves to get multiple values.

Faster processing of association relationships

Simile uses a method called "base instance lookup" to speed up the processing of associations between submodel instances. Previouslly only 1-dimensional fixed-membership submodels could have instances looked up rather than searched for when building an association. Now, the extra functionality described above for element() allows instances of any submodel type to be looked up, so associations can be built faster.

Download Simile v6.1 now!
Jasper Taylor
Posts: 1
Joined: Mon Feb 10, 2014 5:19 am


Return to Announcements

Who is online

Users browsing this forum: No registered users and 1 guest