Wandering Spaceship in Deep Space Chapter 74: You met a real pervert

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

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

　　"Please ask student Cai to answer below."

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

　　 reluctantly recites 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 booing noise from under the 　　. Although classmate Cai blushed, he still stood on the stage bitterly.

　　 He looked up at Zhang Yuan.

　　 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 problem." Zhang Yuan raised his hand, "I have 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 weights are converged, then the output can also fit the expected output, that is, the system is stable, so the convergence For variables, stability is for systems."

　　"The stability of the system cannot be guaranteed, the control system is unstable, and the convergence of the network loses its foundation."

　　 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 it."

　　"...First of all 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."

　　"Secondly, by studying the conditions for the energy function to become a convex function, the operation of the hopfield network is regarded 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..."

　　 This time it was the heart of the questioner. He asked a few more 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 ask me after the stage to discuss it. I won’t explain it in detail here..."

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

There is already a clap of applause under 　　.

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

　　 Cai Kun wanted to find a crack 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. He just happened to encounter a problem that he didn't know but the other party would.

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

　　 The questioner is a girl. Her question is relatively pragmatic and not that partial: "I want to ask one about the cache 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, the available communication resources are used to place the data in each user’s cache device. The second is the data storage. In the distribution stage, it is assumed that during the peak period of data demand, each user randomly requests a complete file from the server. The server comprehensively considers these requirements and distributes complete data to meet the needs of all users."

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

　　 The questioner even posted 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 smiled and said: "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 under 　　 burst into laughter and whistles.

　　Some people believe it, and some don’t.

　　 Cai Kun was taken aback. This time, he still had some thoughts, 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 M/N ratio of each file. In the data distribution stage, the server then sends the missing (1-M/N) data of each user Issued one by one, at this time the value of the transmitted data is R=K(1-M/N)......"

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

　　 "What you say makes sense."

　　 Although I said so, the questioner was slightly disappointed. The coding cache can be said to be the most ordinary idea. There are already mature algorithms for a long time, and there is 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, and he cleared his throat.

　　"Cai Kun’s idea is very good. In the distribution stage, use the relationship between the existing cached information to design a certain encoding combination of the required broadcast content, so that multiple users can simultaneously read from a single message Decoding obtains the required part of the information, thereby obtaining the global buffer gain."

　　" But its limitation is that ~IndoMTL.com~ divides each file into a parameter that grows exponentially with the number of users K. As we all know, exponential division is algorithmically difficult to achieve... "

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

　　 The host was taken aback, "Yes."

　　 Zhang Yuan drew a few pictures on the screen.

　　"... In essence, it is a problem of combinatorial graph theory. What we hope to get is a cache scheme when F is a polynomial level of K and R is a constant level. Or prove the existence of such a scheme ."

　　 "Obviously, whether the number of file divisions can be transformed into a polynomial level, that is, to reach the level that can be used in industry, depends entirely on whether or not a hypergraph problem can be constructed mathematically that satisfies certain characteristics. These characteristics are like this..."

　　" I think that after converting to a mathematical problem, I can write a good paper. As for what the answer is, I definitely can’t answer it now, it’s just an idea. How to solve this graph theory problem specifically, I have to This classmate thinks by himself."

A whisper sounded under the 　　.

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

　　Papa!

　　 A few minutes later, the questioner took the lead and clapped his hands.

　　 There was thunderous applause.

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

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

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

　　 "Yes..."

　　 "It seems that the loss is not wronged."