COVID-19 vaccinations have been administered quickly in the USA. However, a surprisingly large number of Americans are unwilling to get vaccinated. Without enough people getting vaccinated, the pandemic will not end. The longer the pandemic persists, the more opportunities exist for more virulent strains to emerge. This model looks at the effects of people’s behavior in containing and ending the COVID-19 pandemic in the USA. Human behavior adds several feedback loops to the standard SEIR model. Comparisons are made between cases with and without behavior loops, with reduced adherence to the recommended or mandated masks and social distancing, with and without the vaccine, and the effects of an early mask mandate termination. The results suggest human behavior must be accounted for in epidemiology models and that removing masks before enough vaccines are administered not only puts those vaccinated at risk, but allows the disease to readily spread again.

We read each day of new projections on cases, hospital loads and deaths from COVID-19. In this webinar, Dr. Robert Eberlein presents the basic structure of models used to make these projections and the types of information necessary to get accurate projections. He shows different ways to model interventions such as testing, social distancing, antiviral medications, and vaccines, and their effect on the spread and severity of the disease. The presentation builds understanding from the ground up, starting from the framework of a simple diffusion model, and shows how additional characteristics of disease progression can be added in. There is also a discussion of the special challenges that modeling COVID-19 poses relative to the flu and other infectious diseases.

Models used in this webinar are available here. Slides used in this webinar are available here.

Karim Chichakly looks at the efficacy of two policies aimed at protecting both lives and the economy during COVID-19:
1. Vertical isolation, a policy endorsed by President Bolsonaro in April 2020 as a way to reopen the Brazilian economy despite a large number of infections
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2. The CARES Act in the United States, meant to help both businesses and individuals survive the extended lockdown from March to June 2020
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Do either of these policies meet their objectives? I.e., does vertical isolation keep the economy thriving while protecting the lives of the citizens? In the face of stay-at-home orders, do the provisions of the CARES Act protect both businesses and the livelihood of citizens in the short and medium term?

Using Stella® Architect, learn to build, and then deploy to the web an entire user interface for a preexisting model. Learn how to use interactive elements such as: buttons, annotations, images, graphs, sliders, knobs and stories to reveal and explain the insights generated by your models.

Learn how to develop engaging interactive data visualizations powered by your models without writing any code. Change color, scale, rotation, opacity and position of objects to create dynamic animations of your data. Quickly and easily visualize arrayed data or simply create movement to bring your simulation to life.

Learn how to build from scratch a multiplayer simulation game. We'll use Stella® Architect's interface design capability to build a competitive multiplayer game which can be played by 2 or 3 people. Topics covered include templates, simulation events, and publishing. These features require Stella® Architect 1.4.

Models used in this webinar are available here.

During this hour-long free webinar, lead developer Billy Schoenberg teaches the current best practices for constructing multiplayer games including waiting rooms, debrief screen construction, and using wildcards, a feature introduced with Stella® Architect 1.8.2. Wildcards enable the simulation author to reuse pages, graphs, tables, sliders, etc. to display different slices of arrayed variables, making array-based multiplayer game construction quick and efficient.

Models used in this webinar are available here.

Learn how to deploy simulations and models to the isee Exchange ™ using authentication and data collection. We'll discuss how to use the isee Exchange to privately host your content, enabling you to share your work with authorized users only. We'll also discuss how to set up data collection, which allows you to track user activity within your published simulations.

Gain an appreciation for how tools such as STELLA® and iThink® can be used to quickly build effective simulation games for learning and development. The webinar will start by providing context on the rapidly growing market for business simulation games, game-based learning, gamification, and informal learning. Examples of iThink business simulation games will then be presented. The webinar will conclude by covering the key aspects of STELLA/iThink which must be mastered to build simulation games.

Do optimization and calibration confuse you? Are you not sure how to set them up in Stella®? Learn what optimization is, how to use it to optimize and calibrate your models, and how to resolve common pitfalls.

Stella® models show us how systems behave over time as well as help identify system changes that improve outcomes. Optimization allows us to fine tune those changes by finding the set(s) of parameters that give the best possible results. Stella, beginning with version 1.5, provides the functionality to easily set up and perform optimizations.

Models used in this webinar are available here.

Many real optimization problems require finding the ideal trade off between conflicting goals. In these cases, single-objective optimization is not sufficient as it gives you exactly one answer. With multiobjective optimization, you can explore the tradeoff curve or surface and decide yourself which is the best solution for your circumstances. Beginning in version 1.5, Stella® includes the ability to perform optimizations, including true multiobjective optimization using differential evolution.

Successfully developing a model requires you to make sure that it behaves reasonably. What are some simple checks? How do you track down the problem area when it doesn't behave as expected? Join Dr. Karim Chichakly as he walks you through the simple tests to perform in all models, explores the different ways a model can go astray, and shows how to find and fix these problems. Learn how to manually trace a model's behavior and use Causal Lens to make this process easier.

An integral part of working with models is seeing how behavior changes as you vary inputs and assumptions. You can do this by editing equations or adjusting knobs in Stella Live™, or approach it more formally and comprehensively using the sensitivity simulation capabilities in the software. In this webinar, Dr. Robert Eberlein covers the motivation behind sensitivity analysis and demonstrates techniques that Stella® supports for doing this analysis, as well as the tools to view results.

Models used in this webinar are available here.

Stella® provides many ways to import data into models and use that data to refine those models. In this webinar, Dr. Robert Eberlein provides background on validity checking and confidence building, then explains the process to calibrate a model so that its behavior matches the data as closely as possible.

Models used in this webinar are available here.