The military-industrial scientific research system of the academic master.

Perhaps it was due to the attempt when he was just reborn, or perhaps it was due to the fact that his management ability had improved from a blank LV0 to LV1.

In short, the subsequent formation of the research team and the process of assigning tasks to the 606 Institute and the 410 Factory were much smoother than Chang Haonan's own imagination.

After all, the abilities and experience of the engineers who can work in these places have been tested, which is much easier than bringing two undergraduates, Zhou Shuwan and Zhang Man.

When introducing calculation methods and experimental content, it is basically easy to understand.

So that night, the team responsible for the research on the forward sweep of the upper end of the first part of the moving blade and the positive bending of the lower end had already started working.

After assigning the last part of the task, Chang Haonan finally dragged his tired body out of the temporarily assigned office and prepared to go back to his residence in No. 601 to take a rest.

From the day the No. 01 prototype had an accident until now, he has not had a sound sleep.

There are still many problems left for him to solve, and many parts are not simple even with the help of the system. Even if the experimental part has been stripped out, the numerical simulation part alone cost him 50 points.

The main limitation is naturally the level of computers in this era.

The flow field complexity involved in each of the plans he gave is different. The swept blades have modifications with different sweep heights and sweep angles. The curved moving blades also have modifications with different bending heights and bending angles. Without going through the system, Before optimization, the number of automatically generated meshes for each blade was around 90.

Not to mention 1996, even in 2006, it is definitely a number that can make people's blood pressure immediately rise after hearing it.

And the pressure on this matter is greater than previous improvements to the wing design.

While the No. 04 prototype is being refitted with a new wing, the two prototypes No. 01 and No. 03 are still undergoing non-stop test flights, but certain adjustments are needed to the test subjects.

However, the engine, as the heart of the aircraft, had an accident as big as the last one, which almost resulted in the complete loss of the No. 01 prototype. It was obviously impossible to continue the test flight until the problem was solved.

Every day spent delaying this will cause immeasurable damage.

"call--"

Chang Haonan exhaled a breath of turbid air, feeling the already cool evening breeze at night in late August in the north, and couldn't help but quicken his pace.

Just as he was about to enter the dormitory building, the guard on duty at the door suddenly called him from behind.

"Regular worker!"

Although Chang Haonan is not a formal employee of Institute 601, most non-technical staff cannot figure out the more complicated twists and turns, so they are basically referred to as x work.

"Is there something wrong with this comrade?"

Chang Haonan stopped when he heard his name, turned around, and saw a security guard in uniform who looked about the same age as him running out of the guard box with something in his hand.

"This is a letter sent to you. Because I didn't write the specific dormitory number, I left it with the doorman."

"letter?"

Chang Haonan took the brown paper envelope from the other party in a daze, and could not see clearly what was written on it in the dim light.

Not many people knew about his work in Institute 601, and those who knew about it seemed to be able to contact him directly through Yang Fenghata.

"Excuse me, comrade."

"It doesn't matter. Just come to me and sign to confirm receipt."

A few minutes later.

With a soft click, Chang Haonan opened the dormitory door.

Usually after coming back exhausted, the first thing he does is to throw himself on the bed and lie down for half an hour without thinking.

But today, after a brief struggle when going upstairs, Chang Haonan decided that he still had to see what was going on with the letter.

Light the desk lamp.

Although several months have passed since his rebirth, and he has gradually become accustomed to this era without mobile Internet, seeing a letter with a stamp still makes him feel a strange feeling.

The sender column is filled with "Xu Yang, Institute of Computing Technology, Chinese Academy of Sciences."

The pen writing is very beautiful.

"No wonder……"

Chang Haonan said to himself while opening the letter.

We know that he works in the 601 office, but there is no way to contact him by phone and we need to send a letter. It seems that he is the only one.

The folded letter contained nearly 20 pages, and the thickness made him frown.

"Forget it, tear it all apart, let's take a look at what she wrote and then rest..."

Because he opened the letter so quickly, he didn't even have time to recall whether some bloody plot had flashed through his mind at that moment, before he saw the title at the top of the first page.

"Research on an extended Kalman filter algorithm based on improved differential evolution algorithm"

Abstract: The extended Kalman filter has been widely used in various fields such as engineering practice. However, this algorithm brings errors due to the assumption that the process noise is fixed, and the accuracy is not high. An improved EKF algorithm is studied, which mainly improves the filtering accuracy by assuming that the process noise is obtained by filtering results and observation results, and then using a differential evolution algorithm to optimize the obtained process noise variance...

The results show that the improved extended Kalman filter algorithm reduces the state estimation bias and obtains a relatively ideal filtering effect...

"hiss--"

"I kind of regret opening this letter..."

Chang Haonan rubbed his swollen temples, put the letter on the table, got up and left the bedroom.

He was going to make a cup of strong tea.

I'm afraid tonight's rest will be ruined again.

……

A few hours later.

Chang Haonan looked at the letter paper that had been marked with red and blue pencils and the notebook full of writing next to it, and drank the last sip of the bitter tea in the thermos cup.

It can only be said that Xu Yang is indeed a doctor who returned from UCB and personally participated in the development process of the differential evolution algorithm.

Based on the level of ability shown by the other party, it doesn't seem to be an exaggeration to say that she has a system similar to mine.

The ability to draw inferences from one example is quite powerful.

The content of this letter is not too complicated:

After seeing Chang Haonan's improvements to the differential evolution algorithm, Xu Yang proposed a new idea and wanted to discuss the feasibility and application prospects with the latter.

Simply put, filtering is the operation of filtering out specific frequency bands in signals. It is an important measure to suppress and prevent interference. It is almost an essential process for all behaviors that require the emission of electromagnetic signals.

In fact, the least squares method learned in high school mathematics is a classic filtering method. However, since it only considers the relationship between measurement and state, the stability of this method is not good.

Later, the Kalman filter method was born for linear systems whose noise obeys Gaussian distribution. Due to its high efficiency and accuracy, it soon became one of the most widely used filtering methods in engineering.

However, because the original Kalman filtering method was only applicable to linear systems, many people later made certain expansions on this basis so that this well-received filtering algorithm can also be used in nonlinear systems.