Deep Space Planet Leader

"The two contestants, please think for 3 minutes."

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

"Cai, please answer me below."

He blushed and stumbled for a long time: "I'm sorry, I haven't studied this field in depth...recurrent neural network It is an artificial neural network that has a tree-like hierarchical structure and the network nodes recursively input information according to their connection order. It is one of the deep learning algorithms."

I barely recite some definitions, but I can’t get it right. Classmate Cai said: "I'm sorry, I don't have a particularly good idea for the time being."

There was a boo from below. Although Classmate Cai blushed, he still brace oneself on the stage.

He looked up towards Zhang Yuan.

It depends on what you can answer. If you can't answer anything, why do you have a higher interview score than me?

"I have student Zhang answer below."

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

The questioner laughed: "If some of the weights of the network can converge to the equilibrium point, that is, the weights are converged, then the output can also fit the expected 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 cannot be guaranteed, the control system is unstable, and the convergence of the network loses its foundation."

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Zhang Yuan pondered for a while, and said, "I haven't studied your research field in depth, just read some papers. But I have some simple ideas, you can listen to them."

"...First is the monotonicity problem. In the discrete-time continuous state hopfield network model, whether the activation function of the neuron is a monotonic function, or whether it is locally monotonic."

" The second is to study the conditions for the energy function to become a convex function, and regard the operation of the hopfield network as the solution of a constrained convex optimization problem, so as to try to prove whether there is a sufficient condition for the global unique minimum point..."

"Convex optimization, you are right! Convex optimization is the direction I am doing. I have another question..." He also raised a few questions about convex optimization and exchanged mathematics on the spot.

At the end of the host’s instructions, Zhang Yuan had no choice but to say: "If you need knowledge about convex optimization, you can talk to me after the stage. I won’t elaborate on it here..."

Many things are just based on his usual accumulation and casual nonsense. If he can write a essay according to the circumstances, then he doesn’t need to be on stage, just be the "thesis god".

The applause has already come from below.

For such a short period of time, the judgement was decided.

Cai Kun wanted to find a gap in the ground to get in.

He can only blush and cheer himself up secretly, perhaps because of the difference caused by too few samples, and just meets a problem that he doesn't know but the other party will.

The host asked again: "No. 666, please tell me your question."

The questioner is a girl. Her questions are relatively pragmatic and not that biased. Door: "I want to ask a question about caching in the server."

"Caching is divided into two stages: The first is the data placement stage, during the idle period when the data demand is small. , Use the available communication resources to place data in the cache device of each user. The second is the data distribution stage. It is assumed that during the peak period of data demand, each user randomly requests a complete file from the server, and the server considers these requirements. , Distribute complete data to meet the needs of all users."

"My question is, how to design the most scientific caching scheme?"

The questioner even sent a PPT To the screen.

This question is very professional, but everyone can understand what is being asked.

The host said: "Okay, everyone, please think about it for 3 minutes."

The microphone was handed over to Zhang Yuan.

He said with a smile: "I think... let's give the opportunity to classmate Cai Kun first. I'm afraid he won't say anything after I say it."

The people underneath laughed again, and also broke out a whistle.

Some people believe it, and some don’t.

Cai Kun was taken aback. At this time, he still had a little thought, but Zhang Yuan on the other side seemed to be unable to say anything, and needed more thinking time.

"...I have the idea that each user caches the data of the MN ratio of each file separately, and in the data distribution stage, the server then sends the missing (1-MN) data of each user Distributed one by one. At this time, the value of the transmitted data is R=K(1-MN)......"

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

"What you said makes sense."

Although you said so, the questioner was slightly disappointed. The encoding cache is arguably the most ordinary one. This idea has already had a mature algorithm for a long time, and it has no research significance. If you use this bad idea to start a project, it is estimated that you will be slapped back by your instructor.

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

"Cai Kun’s idea is very good. In the distribution stage, the relationship between the existing cached information is used to design a certain encoding combination of the required broadcast content, so that multiple users can download from a single The second information is decoded to obtain the required part of the information, so as to obtain the global cache gain."

"But its limitation is that each file must be divided into an exponential with the number of users K The parameters of growth, as everyone knows, exponential divisions, are algorithmically difficult to achieve..."

"Can I borrow your digital pen and large screen?"

The host was taken aback for a moment, "Yes."

Zhang Yuan drew a few pictures on the screen.

"...In essence, it is a combinatorial graph theory problem. What we hope to get is the caching scheme when F is the polynomial level of K and R is the constant level. Or prove this scheme Existence or not."

"Obviously, whether the number of file divisions can be transformed into a polynomial level, that is, to reach an industrially usable level, depends entirely on whether a hypergraph can be constructed mathematically that satisfies certain characteristics. Questions, these characteristics are like this..."

"I think that after turning into a mathematical problem, you can already write a good paper. As for what the answer is, I definitely can’t answer it now, it’s just a It's just an idea. How to solve this graph theory problem, this classmate has to think about it by himself."

A whisper sounded underneath.

There are still many professionals among the people who eat melons. Whether it is talk nonsense or not, naturally they have their own distinctions.

pa pa pa!

A few minutes later, the questioner took the lead and applauded.

There was thunderous applause.

Cai Kun has no face to continue to stay, his face flushed, and hurriedly nodded to admit defeat.

He finally knows that the same is a one-hundred-point test paper. He tested 100 points because of his strength, while others also tested 100 points because there were only one hundred points on the paper.

"Old Cai, you have encountered a real pervert!"

"Yes..."

"It seems that the loss was not wronged."