"Ask the two contestants to think for 3 minutes."

Soon, 3 minutes later, the host handed the microphone to Cai Kun.

"Please answer Cai."

He blushed and stumbled for a long time: "I'm sorry, I didn't delve into this field...... Recurrent neural network is an artificial neural network with a tree-like hierarchical structure and network nodes recursively incoming input information in the order in which they are connected, and is one of the deep learning algorithms. ”

Reluctantly reciting some definitions, I was really a little confused, and Cai said, "I'm sorry, I don't have a particularly good idea for the time being. ”

There was a burst of boos from below, and although Cai blushed, he still stood on the stage with his head stubborn.

He looked up at Zhang Yuan.

It's up to you to come up with what you can answer. If you can't answer anything, why do you score so much better than me in the interview?

"I would like to ask Mr. Zhang to answer below."

"I have a question." Zhang Yuan raised his hand, "I've heard of the Hopfield network, but what is network stability?" ”

The questioner smiled: "If some of the weights of the network can converge to the equilibrium point, that is, the weight convergence, then the output can also fit the desired output, that is, the system is stable, so the convergence is for the variables, and the stability is for the system." ”

"The stability of the system is not guaranteed, the control system is unstable, and the convergence of the network has lost its foundation."

Zhang Yuan pondered for a moment and said, "I haven't studied your research field in depth, but I've only read some papers. I have some simple ideas though, which you can listen to. ”

“…… The first is the problem of monotonicity, whether the activation function of a neuron is monotonic or locally monotonic in the Hopfield network model of discrete time continuous state. ”

"The second is to try to prove whether there are sufficient conditions for a global unique minimum point by studying the conditions for the energy function to become a convex function, and treating the operation of the Hopfield network as a constraint convex optimization problem......."

"Convex optimization, you're right! Convex optimization is exactly what I'm doing, and I still have a question......"

This time, it was in the heart of the questioner, and he asked a few more convex optimization questions, and exchanged mathematics on the spot.

Finally, under the host's instructions, Zhang Yuan had no choice but to say: "Regarding the knowledge of convex optimization, if necessary, you can find me behind the stage to discuss, I will not explain it in detail here......"

A lot of things he just talks nonsense based on his usual accumulation, if he can really write a paper on the fly, then he doesn't have to go to power, just be a "paper god".

There was already a round of applause from below.

In such a short period of time, the judgment was made.

Cai Kun couldn't wait to find a crack in the ground to get into.

He could only blush and secretly cheer himself up, perhaps because of the difference caused by too few samples, and he just happened to encounter a topic that he couldn't and the other party would.

The host asked again, "No. 666, please state your question." ”

The questioner was a girl, and her question was relatively pragmatic and less off-the-beaten: "I'd like to ask a question about caching in the server. ”

"Caching is divided into two phases: one is the data placement phase, in which data is placed in each user's cache device using spare communication resources during idle periods when data demand is small. The second is the data distribution stage, assuming that during the peak period of data demand, each user randomly requests a complete file from the server, and the server comprehensively considers these needs and distributes the complete data to meet the needs of all users. ”

"My question is, how do you design a caching scheme most scientifically?"

The questioner even posted a PowerPoint presentation on the screen.

The question was very technical, but everyone could understand what was being asked.

The moderator said, "Okay, guys, please think about it for three minutes. ”

The microphone was handed over to Zhang Yuan.

He smiled and said, "I think...... Let's give the opportunity to Cai Kun first. I'm afraid that after I say it, he won't say it. ”

The people below let out another laugh and whistle.

Some believed, some didn't.

Cai Kun was stunned in his heart, this time, he still had a little idea, but Zhang Yuan on the other side didn't seem to be able to say anything, and he needed more time to think.

“…… I have the idea that each user caches the M/N ratio data of each file separately, and then the server distributes the data of the missing (1-M/N) part of each user one by one during the data distribution stage, and the value of the transmitted data R=K(1-M/N) ......"

"I don't know if you've heard of a scheme called 'encoding cache', and the specific algorithm is like this......"

"You have a point."

Although he said this, the questioner was slightly disappointed, encoding cache can be said to be the most mundane idea, and there are already mature algorithms for a long time, and there is no research significance. If you take this rotten idea to start a project, you will probably be slapped back by the tutor.

Then it was Zhang Yuan's turn, and he cleared his throat.

"Cai Kun's idea is very good, in the distribution stage, use the relationship between the existing cache information to design a certain coding combination of the required broadcast content, so that multiple users can decode from a single information at the same time to get the required part of the information, so as to get the global cache gain."

"However, the limitation is that it is difficult to achieve algorithmically ...... to divide each file into parameters that grow exponentially with the number of users

"Can I borrow your pen and the big screen?"

The host was stunned for a moment, "Yes." ”

Zhang Yuan drew a few pictures on the screen.

“…… Essentially, it's a combinatorial graph theory problem, and what we want is a caching scheme at the polynomial level where F is K and R is a constant level. Or to prove the existence of such a scheme. ”

"Obviously, whether the number of file divisions can be converted to a polynomial level, i.e., to an industrially usable level, depends entirely on whether the hypergraph problem can be mathematically constructed that satisfies certain characteristics, which are ......"

"I think I can write a good paper after converting it into a math problem. As for what the answer is, I can't answer it now, it's just an idea. How to solve this graph theory problem has to be thought about by the student himself. ”

There was a whisper below.

There are still many professionals here who eat melons, and they naturally have their own judgment whether it is nonsense or not.

Bang Bang Bang!

A few minutes later, the questioner took the lead in applauding.

There was thunderous applause from below.

Cai Kun no longer had the face to continue staying, his face was flushed, and he hurriedly nodded to admit defeat.

He finally knew that for the same 100-point test paper, he scored 100 points because of his strength, while others also scored 100 points because there were only 100 points on the paper.

"Lao Cai, you have met a real pervert!"

"yes......"

"It seems that the loss is not unjust."