Application of the Markov Process Rainfall Model

Posted by Jason Lillywhite

If you have visited our Model Library lately, you might have noticed that we have a nice little example model that demonstrates the use of a Markov process to simulate daily rainfall. You need to specify some key statistical inputs that have some basis on historic data. How do you develop these inputs? How do you know if the Markov model is realistic? I thought it would be helpful to show how this simple example might be applied in a real-world project and try to answer those questions.

*Note that I made changes to the results on 5/20/2016 after I used GoldSim's optimization function to better calibrate the rate variability.

Automatically Export GoldSim Plots as Image Files

Posted by Jason Lillywhite

Over the last few years, some users have asked us for a feature that automatically exports images of plots in a GoldSim model. This is useful if you want to quickly update many plots used for a report but it is currently not a feature supported by GoldSim. Luckily, there is a fairly straightforward workaround that involves the help of a macro enabled Excel spreadsheet. In this post, I will walk through the steps to build this functionality using a simple example model. Using the simple example that I've created, you just run the model and images of all the plots of exported results are saved immediately.

Using GoldSim to Estimate Forecasting Parameters from Data

Posted by Ryan Roper

Recently, a customer contacted me to ask how to estimate parameters of a best-fit trend line for data stored in a Time Series element. The solution had to be sufficiently generic for multiple data sets and the fitting had to occur at the beginning of a simulation so that the parameters could be used for forecasting. The first solution I proposed used a SubModel with the optimization capability enabled. This worked well for a few data sets, but the solution needed to be scaled up to work efficiently for dozens of data sets on a single run. By the time I had implemented the approach for 10 data sets, I could see that the run time was going to be too long.

Since we had a known equation to fit to the data, I decided to implement a solution using the Gauss-Newton algorithm, an iterative nonlinear least-squares method for fitting trend lines to data (see Gauss-Newton Algorithm). This solution dramatically reduced the computation time and still gave great results. Since I think this solution could be of interest to many users in a variety of application areas, I put together a nice example model and posted it to our model library: Gauss-Newton Trend Line Fitting. In this blog post, I describe the implementation and show some results.

Simulating Active Feedback Control in Engineered Systems

Posted by Rick Kossik

Most real-world models contain many interacting (positive and negative) feedback loops. Some feedback loops are “natural” and cannot be readily managed or controlled (e.g., water evaporating from a pond is an example of a process that forms a negative feedback loop). Others, however, are “intentional” negative feedback loops that are used for active feedback control of a system. That is, these are feedback loops that are part of the design of the system, and are used to make the system behave in a specified manner. A heating system controlled by a thermostat is the classic example of such feedback control. Pumping water to maintain a target water level is a simple water resource example. We discussed using GoldSim to represent such systems in our January webinar.

New GoldSim Help Desk

Posted by Ryan Roper

If you haven't noticed yet, we are now managing our support communications using a cloud-based customer service platform called Zendesk. You can visit the GoldSim Help Desk here:  http://support.goldsim.com/.

After spending about a month evaluating Zendesk, we decided that this would be an excellent system for helping to track and document interactions that we have with you. It's also a great environment for maintaining a knowledge base of helpful support articles.

New GoldSim Licensing System Now Available

Posted by Rick Kossik

In a previous post, I noted that we will be rolling out a new licensing system.  The system has now officially been implemented. Over the next several months, we will be rolling the system out to existing users. To continue to use GoldSim, you will need to migrate your license over to the new licensing system.  The conversion process is straightforward, and should not take long (minutes in most cases).  You can read about the details of the new licensing system here.  Note that all licenses (even older licenses with expired maintenance) will need to be converted (there is no cost involved). 

The new system has a number of powerful advantages, particularly for organizations with multiple licenses and/or floating licenses.  Hence, we will be contacting these organizations over the next month to begin the conversion process. For everyone else, you do not need to change over immediately.  Instead, whenever a license expires or needs to be renewed, we will convert it over to the new system.  Having said that, regardless of how straightforward the conversion is, it always has the potential to disrupt some users, so executing it on your schedule (rather than waiting for your license to expire) is recommended. Hence, if you would like to convert over immediately (and not wait until your license needs to be renewed), you can switch over to the new system now by contacting us. 

Central Arizona Project - Service Area Model

Posted by Jason Lillywhite

GoldSim is being used by engineers and planners at Central Arizona Project to simulate water management in an area experiencing rapid growth coupled with uncertainties about future water supply, demand and reliability.

The Central Arizona Project Service Area Model (CAP:SAM) was developed by in-house staff using GoldSim software to simulate water demands for all major water using entities in the CAP three county Service Area, and the water supplies they use to meet their demands.  The model can be used to simulate a wide range of future conditions including variable rates and patterns of growth, shortage impacts, effluent reuse, aquifer recharge and recovery, and complex supply portfolio management decisions on an annual time step.

Time Series: Modeling Changing Amounts Over Periods

Posted by Jason Lillywhite

A common modeling requirement in GoldSim is to represent movement of (or changes in) amounts of material over time intervals. Common examples we have seen from our users are flows through a pipe, site runoff, and rainfall amounts. Representing this type of data can be challenging if you are not used to GoldSim's way of explicitly defining data in the Time Series element. I think a reason for this is due to our familiarity with spreadsheets, which do not require explicitly defining how the data is represented.

Top Downloads from the GoldSim Model Library

Posted by Jason Lillywhite

We are continually updating and maintaining models in our Model Library in order to help our customers answer complex questions. You may not be aware but we now have 170 models in our library which are all available for all GoldSim users. These models are either built for a specific application or just to demonstrate a generic functionality of the software. It turns out that our most widely used model examples are application specific.

We track how often each of our models are downloaded and so I thought it might be helpful for you to see which ones are the most popular. Below is a summary of our most popular model library downloads since the inception of our library in early 2013. The models listed below are shown in order of popularity, with our most popular model shown first.

New Licensing Tools Coming to GoldSim in Early 2016

Posted by Rick Kossik

Software licensing tools are usually intended to be something that neither the user (you) nor the software vendor (us) want to have to think about often.  In a perfect world, you activate or register your software, and then don't want to have to think about it again for a long time (e.g., perhaps until you upgrade the license or extend the maintenance subscription one year later). Although this is the case for many people, we have found that a growing number of our users want more flexibility and capabilities with how they manage their licenses.  To address this, we've spent the last year implementing a powerful new licensing system that among other things, will make it easier for users to track and share licenses within an organization. In this blog, I provide a quick overview of the new licensing features.

Dynamic Coupling of GoldSim and MODFLOW / MT3D

Posted by Jason Lillywhite

From time to time, we hear from GoldSim users asking about the possibility of linking MODFLOW with GoldSim dynamically. This is important because the combined model is useful for integrating accurate groundwater flow and transport models with decision support, hydrologic, and probabilistic models built in GoldSim. Folks at Barr Engineering were able to pull this off using a realistic hypothetical application and presented their application at the poster session of our 2015 User Conference.

GoldSim Training Course in Tucson in December

Posted by Rick Kossik

I'll be teaming with Dave Hoekstra of SRK Consulting to teach a 3-day course entitled "Developing Mine Water Balances in GoldSim" December 3-5 in Tucson. This course is being held in conjunction with the Society for Mining, Metallurgy, & Exploration (SME) Arizona Conference. I'll be leading the first two days, which are targeted at people new to GoldSim and will cover basic use of GoldSim. Dave will spend the third day focusing on water balance modeling. If you are already familiar with GoldSim, you can attend just the third day. You can read more about the course and register here.

Powerful Decision Making for a Phosphate Mine

Posted by Jason Lillywhite

One of the winners of the 2015 User Conference poster session presented on a GoldSim application for a phosphate mine in central Florida. After reading more about this application, I began to better appreciate the great work that Cardno has been involved in. The phosphate mining industry faces very strict effluent limitations while having to manage several hundred gallons of water around the site every day. The model must account for a continuously changing landscape of flow paths and operating schemes under varying hydrologic conditions. Read about how GoldSim is being used to help the mining company make better decisions as they comply with these changing regulations.

Photos from the User Conference

Posted by Jason Lillywhite

The 2015 GoldSim User Conference was held September 24th and 25th in Seattle and was a big success. Here are some photos showing the highlights of the conference, including the social events and poster presentations. 

GoldSim Model Beauty Contest Winner: Moneyball!

Posted by Rick Kossik

A tradition at our User Conference is to hold a "Model Beauty Contest".  The Beauty Contest is held at the end of the Conference, and is intended to allow our users to focus on the fun side of modeling and simulation.  Beauty Contest entries typically describe a modeling application that is light-hearted (such as a game), amusing (e.g., probabilistically simulating the length of the restroom lines at a football stadium), or simply entertaining. This year's winner (as determined by a vote of attendees) was Joe Donnelly's "Moneyball" model.

GoldSim User Conference Poster Session

Posted by Rick Kossik

We just wrapped up our User Conference in downtown Seattle, and it was lots of fun.  The conference was attended by nearly 60 people from six countries.  In addition to invited papers, a panel discussion, and a day of advanced training, one of the highlights of the conference was the poster session, where attendees presented a wide variety of interesting GoldSim applications. This post provides a list of poster abstracts and presents the winners (as selected by attendees) of the best poster presentation.

Pre-Conference Training has Started!

Posted by Ryan Roper

The first wave of GoldSim users have arrived to participate in our 2-day pre-conference training course at the Washington Athletic Club in downtown Seattle. This is a prelude to our 2015 GoldSim User Conference, which will start on Thursday. The night before conference kickoff, attendees (55 in total), coming from six different countries, will enjoy a pre-conference meet-up at the Fado Irish Pub.

Advanced training on the first day of the conference will be a mix of training classes and informal discussions in which attendee participation is encouraged. The day will end with a fun social event on a privately chartered boat ride in the Puget Sound. On the last day of the conference, presentations of invited papers, poster presentations and a panel discussion will provide opportunities for attendees to network, share experiences and participate in interesting discussions.

We expect to have a really great time this week!

GoldSim: The Swiss Army Knife of Simulation Tools

Posted by Ryan Roper

I recently sat in on a great guest webinar (John's Grab Bag of Tips 'n' Tricks) presented by a long-time GoldSim user, John Tauxe, and I was impressed by how he has stretched the bounds of GoldSim's capabilities. At its core, GoldSim is a versatile simulation tool that incorporates probabilistic, discrete events and system dynamics modeling. That alone makes it quite unique among simulation tools. With nearly 40 core elements as well as almost 20 more specialized elements, there is significant flexibility in the way you can model physical, engineered, financial and business systems. If you think about it long enough, there's probably a way to do what you need to do with the built-in elements and modeling capabilities of GoldSim.

http://www.thisiswhyimbroke.com/the-ultimate-swiss-army-knife

But John's webinar also highlighted a whole other world of things that you can do with GoldSim. From internal documentation to graphics drawing tools to dashboards and more, GoldSim is more than just its core simulation capabilities. In the world of simulation tools, it's actually quite like having a corkscrew, nail file, scissors and toothpick on your pocket knife. Here, I want to highlight a few things that stood out to me in John's webinar. I'd also like to make mention of some features of GoldSim that I have used to my advantage in developing a system for automated verification testing of GoldSim. This includes using Spreadsheet elements to export test results to Excel, recording Time Series elements to store expected results for comparison and a batch file to run multiple tests automatically one after the other.

GoldSim in the Academic Community

Posted by Ryan Roper

Most of you are probably aware that GoldSim is used for a wide variety of commercial applications including mine water balance, water resource management, radioactive waste management, project planning and risk and reliability analysis. There are active commercial users in over 50 countries (http://www.goldsim.com/Web/Solutions/Customers/). In addition to these, however, we have another group of users that you may not be aware of: the academic community. There are GoldSim academic licenses at about 150 universities in over 40 different countries.

Learning to Use GoldSim

Posted by Rick Kossik

I am often asked what is the best way to learn GoldSim. Although GoldSim’s intuitive interface will tempt you to simply dive in and start playing with the software, you are strongly discouraged from doing so, even if you are an experienced modeler.  Spending an hour or so up front (by following a few basic steps) is the quickest and most effective way to understand the software’s features and capabilities and start building models in GoldSim. This blog provides some simple tips.