Fall 2005

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Dynamically adjusting timesteps. You can dynamically adjust (adapt) the timestep during a simulation based on the values of specified parameters in your model. For example, you could instruct GoldSim to use a timestep of 1 day if X was greater than Y, and 10 days if X was less than or equal to Y. Similarly, you could instruct GoldSim to use a short timestep for a period of 10 days after a particular event occurs, and then return to the default timestep. To learn more, search for "timesteps, dynamically adjusting" in the Index tab of the Help file.



The GoldSim Knowledge Base contains articles addressing frequently asked questions, workarounds for known problems, and advice on applying GoldSim. The Knowledge Base is available from within the GoldSim Resource Center (GRC).

We encourage you to visit the Knowledge Base, as even expert users are likely to find useful information there.



The GoldSim Model Library allows GoldSim users to build on the experience and knowledge of others by sharing models. The Library is available from within the GoldSim Resource Center (GRC).

If you have a model that you think would be worthwhile to post to the library, please send it, along with text describing the model, to support@goldsim.com.



Welcome to the Fall 2005 Issue of the GoldSim Newsletter!

The mission of the GoldSim Technology Group is to provide state-of-the-art software, training and expert consulting to help you understand complex systems and make better decisions in an uncertain world. Our GoldSim simulation software package provides the power, flexibility and usability necessary to efficiently simulate and understand the future behavior of complex systems in business, engineering and science.

The purpose of the GoldSim Newsletter is to provide information that helps you get the most out of GoldSim. Like you, we don't like getting lots of unnecessary email in our Inbox, so we only send out our newsletter if we have something useful to communicate (usually 2 to 4 times per year). This issue of the Newsletter focuses on the release of our new Reliability Module, and also presents several other items of interest, including an interesting application of GoldSim submitted by one of our Research users, and news on what we are planning for our next release.

Note that each Newsletter is archived on our website so you can view old issues.

Since this newsletter is for you, we encourage you to send us your comments and contributions. Send your contributions to support@goldsim.com.

The GoldSim Technology Group



GoldSim Reliability Module Released!

Developed with partial funding from NASA, the GoldSim Reliability (RL) Module is an add-on extension to the GoldSim simulation framework that allows you to probabilistically simulate the reliability and performance of complex engineered systems over time. GoldSim provides the ability to model the interdependence of components through requirements and fault trees, as well as the capability to define multiple independent failure modes for each component. This facilitates both reliability modeling and risk analysis within a variety of industries, including space and defense, manufacturing, mining, telecommunications, electronics and infrastructure.

The Reliability Module Learning Edition is automatically included with Version 9.1 of GoldSim. This includes all the capabilities and features of the Reliability Module, but limits the number of Reliability Module elements that can be added. However, it provides all users with an opportunity to experiment with this new module.

In addition to the Reliability Module, Version 9.1 also includes a number of minor fixes and user-interface improvements.

All current members of the GoldSim Subscription Program can download Version 9.1 now from the GoldSim Resource Center (GRC). If you are not a current member, but would like to test drive the Reliability Module, request an Evaluation version.


GoldSim Contributes Chapter to GIS Book Published by ESRI

The GoldSim Technology Group (GTG) contributed a chapter to the book "GIS, Spatial Analysis, and Modeling" published by ESRI Press and edited by David Maguire, Michael Batty and Michael Goodchild. The book is concerned with modeling and spatial analysis within a GIS (geographic information system) framework and takes a pragmatic, software-centric view of the tools, techniques, methods and models currently available to geographic analysts, modelers, software engineers and GIS professionals. The book is a direct outcome of a workshop held by ESRI in late 2003 that assembled a small expert group with hands-on experience of modeling within, and linking to, commercial GIS software.

The chapter that GTG contributed to the book, "Linking General-Purpose Dynamic Simulation Models with GIS" describes different classes of dynamic GIS models and discusses two alternative conceptual approaches for linking general-purpose dynamic simulation models with GIS. As part of this discussion, the prototype to link GoldSim to GIS is briefly described. The chapter closes by describing some of the technical issues involved in creating a robust system that would provide the simulation model/GIS linkage.



Simulation of Animal Nutrition Using GoldSim

In this featured example, Dr. David Pachero of the AgResearch Ltd. Grasslands Research Centre in New Zealand illustrates how he is using GoldSim in animal nutrition research. In New Zealand, the dairy industry relies heavily on the ability of dairy cows to utilise forages as their main dietary staple. In grazing systems, the quality of the pasture is an ever-changing playing field: weather, forage variety, level of fertilisation, and age of the plant are some of many factors influencing the quality of the cows' diet. The chemical composition of the forage, and hence its nutritive value, change from season to season, from paddock to paddock, from day to day and even within the same day! Dr. Pacheco used GoldSim to simulate changes in the chemical composition of pasture and its effects on dairy cows.



Here are some of the things that we are working on for our next version (code named Glacier), which we are hoping to released in January 2006:

  • Stochastic Optimization. The Optimization capability introduced in Version 9 will be enhanced to allow you to optimize uncertain systems. It's going to take some time to run these analyses, but you will be able to address problems such as "Adjust my pricing scheme so as to maximize my expected profits, while having no more than a 10% chance of going broke".

  • Two-Dimensional Monte Carlo. We're adding a capability for you to embed one GoldSim model inside another. This should be particularly useful for cases where you need to separate the effects of uncertainty from randomness/variability. You will be able to have an outer Monte Carlo model that samples the uncertain parameters, and an inner model that simulates system performance subject to random effects.


As always, we encourage our users to send their requests and suggestions for improvements to GoldSim. If you have a specific request, please contact us at support@goldsim.com.

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