PID Controller in GoldSim

Posted by Jason Lillywhite

The proportional-integral-derivative (PID) controller is a useful feedback control mechanism commonly used in industrial applications such as furnace temperature control, pH neutralization, and flow control. These systems commonly require that their state be monitored continuously and controls adjusted based on error from a setpoint or target. As seen in the schematic below, the controller makes a change to a process then a sensor is used to provide feedback to the input of the controller.

This type of control can also be used for controlling inflows and/or outflows from a storage facility like a lake or water tank. This blog post describes the application of the PID controller in 2 different GoldSim models: a detailed process flow model with a cylindrical tank and an environmental system with a large water supply reservoir. This logic is found to work well in both cases even though they .

GoldSim 12.1 is Released!

Posted by Rick Kossik

We are excited to announce that GoldSim 12.1 is now available.

In addition to a number of other changes, GoldSim 12.1 includes the following new features:

•  Embedded dashboard charts and tables: You can embed a result window (as either a chart or a table) directly into a Dashboard. 
• Real-Time updating of result displays: Time History results are updated continuously (each timestep or each realization) during the simulation. 
• Exporting time history probability statistics to a spreadsheet: Export multiple statistics from Probability History results.
• Model inventory: Generate a simple XML file that can be viewed in a text editor, browser or XML editor that echoes out all of the elements in a GoldSim model. 

All of the new features in GoldSim 12.1 are described in detail in the GoldSim 12.1 Summary Document.

In addition to an updated Help system to describe all the new features, updated user manuals are installed with the software (in PDF format). Bound manuals can also be ordered directly from Amazon.com (and this is likely to be less expensive than printing and binding them yourself).

You can download GoldSim 12.1 directly from the GoldSim website. In order to use GoldSim 12.1, you must enter a new Activation ID. All users with current Maintenance should have received a new ID.

Building Blocks in GoldSim

Posted by Jason Lillywhite

One of the many strengths of GoldSim is its graphically enhanced user interface, which allows you to quickly build your model from reusable components. During a recent webinar, I built a reservoir operations model that receives water from a snowmelt driven watershed using 6 existing models found in our Model Library. Once I understood what my modeling requirements were, I was able to quickly compile a probabilistic system model that is powerful in demonstrating how to operate a dam that services changing water demands and climate scenarios, which protects against downstream flooding.

GSPy: GoldSim/Python Interface for Scripting Support

Posted by Ryan Roper

We want to alert you to an exciting new addition to our model library, a ready-to-use GoldSim/Python interface that enables you to define external functions in pure Python which are called by GoldSim during a simulation. Both 32- and 64-bit binaries are available, so you can choose the appropriate one for your installation of Python. Source code is also included for reference (or further development), if you are interested to see how the interface is implemented.

The GSPy interface provides support for passing scalars, vectors and matrices as input and output arguments, which we anticipate will meet the majority of interested users' needs. For more extensive support of data types (such as Lookup Tables and Time Series Elements), refer to this related model library example: Python DLL. One key difference between the two examples is that Python DLL uses Cython, a code generation tool, and must be compiled before you can use it. In contrast, GSPy does not require Cython-generated compilation and it is distributed with binaries requiring minimal setup. It also supports error relay from the Python module to GoldSim.

The following steps are recommended to get started:

1) Install the 32- or 64-bit Python 3.6 Anaconda distribution here: https://www.anaconda.com/download/. A significant advantage of installing the Anaconda distribution is that it comes already with several widely-used Python libraries such as NumPy, Pandas and SciPy. One of the examples that comes with GSPy uses NumPy to do matrix arithmetic.

2) Download and unzip GSPy.zip and follow the setup and testing instructions in the README.txt file. Binaries include GSPy.pyd and TestGSPy.exe (32- and 64-bit versions). The README provides simple instructions for setting an environment variable (GSPY) with the path to your Python installation and running TestGSPy.exe from a command line console to confirm that everything is set up correctly.

3) After you have confirmed that the GSPy environment is set up correctly, be sure to go through the three GoldSim model examples included in the zip file: GSPyScalarAddition.gsm, GSPyMatrixAddition.gsm and GSPySnowmelt.gsm. It is strongly recommended that you read through the detailed comments in the corresponding Python module files: GSPyModule_ScalarAddition.py, GSPyModule_MatrixAddition.py and GSPyModule_Snowmelt.py (note, as described in the README, you must change the name of the Python file to GSPyModule.py before running the example).

Have fun and please send us questions and feedback at support@goldsim.com. Or better yet, come to our forum and post about it there where everyone can see it. We see great potential in combining the Monte Carlo simulation capabilities of GoldSim with the extensive well-supported and powerful scientific computing Python libraries that are freely available. The more chatter about this the better. So far, the topic has popped up in a couple places (here and here) in our forum. We hope to hear from you.

The following results were generated by GSPySnowmelt.gsm, which calls a Python implementation of the snow-17 snow accumulation and ablation model (Anderson, E. A. (1973), National Weather Service River Forecast System Snow Accumulation and Ablation Model, NOAA Tech. Memo. NWS HYDro-17, 217 pp., U.S. Dep. of Commer., Silver Spring, Md.).

GoldSim User Conference and Training: September 10-12, 2018

Posted by Rick Kossik

We are excited to announce that the next GoldSim User Conference will be held in Seattle on September 10-12, 2018. GoldSim user conferences provide great learning and networking opportunities for both expert and novice users.

The conference will be preceded (on September 10) by an optional one-day Basic Training workshop focusing on novice users (and could also serve as a refresher course for more experienced users who have not used GoldSim recently). This training opportunity is particularly valuable since after attending the training you will then be able to meet expert users from around the world during the conference.

The conference itself will be held September 11 and 12. On the first day of the conference, Two parallel advanced training sessions will be held. Each session will consist of a series of 1 hour training workshops on advanced GoldSim applications and modeling techniques. Attendees will be able to move between the two sessions in order to select the workshops that best align with their interests. Topics will be based on attendee requests specified on Registration Form. The second day of the conference will consist of a number of invited papers by GoldSim experts, panel discussions, and a poster session. 

To facilitate effective networking opportunities, the Conference will host two fun social outings in Seattle during the evenings of September 10 and September 11. These events not only provide a great opportunity to meet and socialize with other GoldSim users and GoldSim staff, but also allow you to enjoy the sights of Seattle. Spouses/partners can attend these two events (for a modest fee).

Learn more.

Applying the GoldSim WGEN Model to Generate Stochastic Weather Data

Posted by Jason Lillywhite

Now you can let GoldSim do all the heavy lifting for you when simulating weather for your next project. A new GoldSim model example in our library lets you quickly generate the input data required to run the WGEN model, which is a stochastic weather generator built in GoldSim that creates daily stochastic time series of precipitation, temperature, and solar radiation.

This model (called WGENprep) uses time series data to automatically generate the input file you need to run WGEN. The WGEN model requires a lot of statistical information in order to run it and it can be quite a project to develop these inputs. With WGENprep, you can simply input the time series, change the simulation start and end time to correspond to the time series and the model will automatically export all the WGEN input data to an Excel spreadsheet. All you have to do is start up the WGEN model and then copy and paste the data from Excel right into the WGEN dashboard. These models were recently put to the test using some observed historical time series data gathered from the Salt Lake City airport weather station, provided by the NOAA National Centers for Environmental Information website.

GoldSim at AWRA 2017 National Conference

Posted by Jason Lillywhite

The GoldSim booth in the exhibit hall

I recently traveled to Portland, Oregon for the AWRA 2017 National Conference to exhibit and participate in a presentation. With over 70 oral presentations to choose from, I was able to hear about a lot of the latest developments in the world of water resources. I also learned more about some of the unique challenges the Pacific Northwest is facing due to climate change, flood risk, and water quality concerns. Some topics were particularly relevant to GoldSim, such as decision support, risk-based planning, human health risk, reservoir operations, and fate of contaminants in water systems.

An interesting GoldSim application was presented by Rebecca Pluche of San Francisco Public Utilities Commission to summarize on-going work to help manage critical dam operations during construction onsite.

Training Workshop in Phoenix, AZ

Posted by Jason Lillywhite

GoldSim Technology Group provided on-site training for the Arizona Department of Water Resources in Phoenix, Arizona last week. This training covered the basics of GoldSim software along with another full day of application specific training, discussing real-world examples and modeling tips to help the attendees start work on their projects immediately.

The class was well attended and everyone enjoyed learning the software. I could tell everyone was thinking about all the ways they could use GoldSim to help answer their challenging questions.

GoldSim at AWRA Summer Specialty Conference 2017

Posted by Jason Lillywhite

GoldSim presented a workshop and exhibited at the American Water Resources Association (AWRA) Summer Specialty Conference last week.

The theme of the conference was “Climate Change Solutions: Collaborative Science, Policy and Planning for Sustainable Water Management.”  The conference included many presentation and sessions on a variety of topics covering science, data, modeling, and tools for assessing climate risk and making water resiliency decisions based on cost/benefit factors.

GoldSim at Waterpower Week in Washington

Posted by Jason Lillywhite

GoldSim is exhibiting at the Waterpower week in Washington conference this week. This conference provides three conferences into one:  International Marine Energy Conference, Marine Energy Technology Symposium and National Hydropower Association's Annual Conference, which have teamed up for a 3-day event to network and discuss the news in the hydro and marine industry in Washington DC. The event highlights perspectives on the role of hydro, explores issues affecting hydro and marine resources, and helps participants develop a future game plan to meet challenges and ensure the future sustainability of the hydro and marine industry.

Free, Self-Paced Online Training Course Now Available!

Posted by Rick Kossik

We are excited to announce that the GoldSim Online Training Course is now available. We have been working on this for two years (creating an effective online course is hard work)!  This “hands-on” course includes nearly sixty exercises and examples, and is linked throughout to a web-based version of the Help system, so you can immediately dive into reference documentation to explore any topic in more detail.

This self-paced course provides you with a thorough understanding of the key concepts on which GoldSim is based. As such, it provides the fundamentals required to build complex models of nearly any kind of system. That is, it does not simply focus on the mechanics of using the GoldSim software; just as importantly, it explains the fundamental concepts underlying dynamic, probabilistic simulation in general. Although the course was primarily designed for those who are new to GoldSim, existing GoldSim users are also likely to find many parts of the course to be of value.

When an introductory GoldSim course is taught in person, it typically requires two (intensive) days (16 hours).  However, this course actually covers the material in significantly greater detail, so it will likely take up to three or four days to complete. The course is organized into Units and Lessons, so you can easily take the course at your own pace (and if you register, the site will remember where you left off).

GoldSim 12 Has Been Released!

Posted by Rick Kossik

GoldSim 12 has been under development for over two years and we are very excited about this new version.  There are many new features and modifications in GoldSim 12.  However, the most noticeable thing is the totally updated graphics engine and user interface. Although changes like these don't actually affect how GoldSim carries out simulations, they have a significant effect on how your models look. Being able to explain a model to others is critical, and a clean-looking model with nice graphics simply is much more effective and easy to communicate.  Frankly, it is also much more enjoyable to work with a tool that has nice graphics and a clean and powerful user interface. All of the new features are described in detail in the GoldSim 12 Summary Document.

GoldSim 12 Beta is now available!

Posted by Jason Lillywhite

GoldSim 12 is ready for use! It is has passed our rigorous testing process and now ready for beta testing. Before officially releasing the software to the public, we want to extend an invitation to experienced GoldSim modelers to try out the software and provide us with feedback and questions. If you are interested in trying the GoldSim 12 beta, please let us know and we can send you the software and a temporary license. Please send your request for the beta software to our help desk, here.

GoldSim 12 Preview (Part IV): The Pool Element

Posted by Rick Kossik

This is the fourth in a series of blog posts in which I briefly introduce many of the exciting new features that will appear in GoldSim 12 (the previous post can be found here). We plan to release GoldSim 12 in February 2017. Today's blog post focuses on a powerful new stock element: the Pool. A Pool is an expanded (and more powerful) version of the Reservoir element. It can do everything that a Reservoir can do, but has additional features to make it easier to manage multiple outflows (and inflows). As a result of these features, if you are modeling a system that has multiple distinct outflows, you should use a Pool rather than a Reservoir. In fact, we expect the Pool to replace the Reservoir for many types of applications (e.g., water management models).

Calibration of Watershed Runoff Using AWBM in GoldSim

Posted by Jason Lillywhite

Last month, I presented a Webinar on Runoff Modeling in GoldSim. You can find the video recording of the presentation here. I learned a couple of lessons while building the models used for the demonstration and I thought it would be helpful to write about these lessons in a blog post.

GoldSim Workshop at AHS Symposium in Tucson

Posted by Jason Lillywhite

GoldSim Technology Group collaborated with the Arizona Hydrological Society last week to provide a 1-day software training workshop as part of their annual conference. The workshop was well attended by folks from various organizations and companies in the area. Following the workshop, I was able to meet new people and learn more about the current water resources issues in the Southwest.

Read about the symposium here.

GoldSim 12 Preview (Part III): New Run Controls

Posted by Rick Kossik

Run Control toolbar

This is the third in a series of blog posts in which I briefly introduce many of the exciting new features that will appear in GoldSim 12 (the previous post can be found here).  Today's blog post focuses on the new ways in which models are run and controlled. In GoldSim 12, this has been streamlined significantly, such that the old Run Controller dialog has been eliminated, and replaced with a new toolbar and new features within the status bar.

GoldSim 12 Preview (Part II): Updated Behavior of Input and Output Ports

Posted by Rick Kossik

This is the second in a series of blog posts in which I will briefly introduce many of the exciting new features that will appear in GoldSim 12 (which we plan to release in February 2017).  The previous blog post discussed several of the key features of the updated graphics and user interface for GoldSim 12. Today's blog post focuses in detail on one of the features we briefly discussed in the last post: the updated behavior of input and output ports.  This feature is important because it will have a significant positive impact on the appearance of your models.

GoldSim 12 Preview (Part I): Updated Graphics and User Interface

Posted by Rick Kossik

We have spent the last two years working very hard on the next major GoldSim release: GoldSim 12. Our goal is to release this in February 2017.  There are many exciting features in the new version. Over the next several months in this blog I will start to briefly describe the most important of these.  Today's blog will discuss several of the key features of the updated graphics and user interface for GoldSim 12.

Computing a Moving Average

Posted by Rick Kossik

GoldSim allows you to compute and display average outputs of any variable you are simulating.  For example, if you were using a daily timestep, you could compute monthly or annual values using a feature in GoldSim called reporting periods. These are defined in the Simulation Settings.

In some cases, however, you may want to compute a different kind of average – a moving average. For example, at any point in the simulation, you might want to reference the average value of a variable over the previous 10 days. GoldSim provides an easy way to do this.