Kaijian Hu

Watersheds offer vital livelihoods for their residents, but their natural resources are limited, frequently under strain, and at risk of destruction. The main issue is generally degradation induced by unsustainable use of natural resources. Poverty, food insecurity, and social unrest result.

Serious socioeconomic issues can be significant impediments to carrying out watershed work in undeveloped nations. Any major issues should be highlighted at the start of the planning stage. These may include issues such as land tenure, poverty, education, low acceptance of innovations, seasonal labor shortages, and so on.

Every day, save water. Reduce the length of your showers, repair leaks, and switch off the water when not in use. Do not flush poisonous home chemicals down the drain; instead, take them to a hazardous waste disposal facility. In your yard, use resilient plants that require little or no watering, fertilizer, or pesticides.

A watershed is a geographical area that has a common collection of streams and rivers that all flow into a single wider body of water, such as a larger river, a lake, or the ocean. The Mississippi River watershed, for example, is massive. Small watersheds are frequently a portion of bigger watersheds.

Dear Kaijian HU,

If I understood your question correctly, here is my answer on the subject. The history of this field has followed an ancestry according to technological development.

The first watershed was the advent Tuning controle using classical PID, Adaptive and Predictive control using the foundations of optimality, also the second one was the arrival of intelligent control such Artificial Neural Network, Fuzy Set and Machine Learning. We can found also the hybrydation of such methods.

Best regards

Hello Kaijian Hu

Judging from the very different answers you have received, I think some readers view the word "watershed" in its literal sense: as a bounded area where water is diverted, while other readers take the word to mean simply a dividing point or line independent of what is being divided.

Regards,

Tom Cuff

Hi Dr. Kaijian Hu

Looks like a lot of "we" do not know because the term refers metaphorically to the geological "watershed". We can google, but it is best for you to explain clearly.

Hi Kaijian Hu

Thanks for your clarification. There are many classifications for the control systems apart from the generic linear vs. nonlinear systems, such as the affine vs. non-affine systems, for example:

i. x'' = x + u,

ii. x'' = x·u,

iii. x'' = sin(x) + u,

iv. x'' = sin(x)·u,

as well as the delay-free vs. time-delay systems, time-invariant vs. time-varying systems, continuous-time vs. discrete-time systems, integer-order system vs. fractional-order systems, and Newtonian vs. non-Newtonian system.

Perhaps, you can conceive a new integral transform method to solve a special class of nonlinear differential equations. Just select a special class like the equations that you frequently encounter in your engineering field, is a good start.

https://en.wikipedia.org/wiki/Integral_transform