DA Digital Analytics

8/10/2023 --- New Scientific Calculator

I have put together a scientific-style "QuickCalc" calculator, borrowing and modifying code from the formula evaluator of EdTech. The goal is to let the user pop up a single window and quickly evaluate numerical expressions. Since there are a lot of free calculator programs around including the one which comes with Windows, mine is free also. It runs on any Windows from 2000 on up. If anyone is interested in having a Linux version, I might be interested in learning Linux. All my other applications are strictly Windows (from 2000 on up).

8/30/2022 --- "Reboot" of Digital Analytics!

I have neglected Digital Analytics applications for some time. However, now I would like to remind potential or actual users that I am still offering a limited amount of my past work online. I have recently (last winter) assisted new users by email and Zoom. I have retired from my previous teaching position and can consult on projects that are suitable for my software.

Current additional offerings are:

EDTECH --an application to create and edit technical-style black&white graphs & drawings -- Freely downloadable.

DMSolver--a system used to solve large systems of algebraic and or ordinary differential equations, suitable for various types of simulations with equations (simple or possibly highly complex) programmed as functions by the user -- copy protected and must be registered, but you get a 30-day free trial.

BOAT3D --a planing boat simulation model-3 degrees of freedom of motion with math based on DMSolver -- copy protected and must be registered, but you get a 30-day trial for a $300 fee.

Flash Calculator versions:

Demo Flash Calculator -- Does chemical phase equibrium for up to 3 components-- Freely downloadable.

Non-demo Flash Calculator--for many components and can make graphical plots of several types -- copy protected and must be registered, but you get a 30-day free trial.

In the spirit of change I have re-done this website in modern (but simple) html instead of using the ancient WebExpress application.

In 2020 I thought hard about modeling covid. Previous textbooks of infectious diseases had simple models based on something like

(Increase in infections) = Kx(Infectious people) x (Susceptible people) - (people recovering)

and so forth.

I realized that infectious people included those just becoming infectious plus those who became infectious yesterday plus those who became infectious on the day before that plus ... until time enough that they would not be infectious any more. This could be done, I thought, using the lag feature of DMSolver. But, I found that the lag feature had bugs and did not work. I developed version 6.04 whose lag feature was fixed, replacing 6.03 which has the bugs.

However, there are so many different regions (DMSolver handles regions) with different modes of infection, and for that matter, covid has evolved frequently, so I decided that any such kind of model would be pure speculation and after the lag bugs were fixed, I retired from working on any kind of new modelling.

Now I would like to reboot and get someone to use DMSolver on some kinds of manageable problems. I suspect that it could best be used in various kinds of chemical kinetics and reactor design, or simulation of specialized parts of processes. At some point in the past I learned that for typical standard distillation modelling, other commercial systems greatly outperformed the ones I had done, so traditional chemical plant flowsheet simulation has been dropped.

So I may be able soon to look for new problems to try on it and hope I can get someone else interested.

F. Dail Singleton, PhD