Mathematical problems in mining
Publish: 2021-05-06 09:15:10
1. In order to know what mining is calculating, we must first know the essence of bitcoin and its proction process. Bitcoin is a network-based electronic currency, which is actually a string of codes of the Internet, calculated by algorithms. Mining is the process of completing the algorithm and the only way to proce bitcoin. And because of the algorithm, there are only 21 million bitcoins
1. Mining can not only proce bitcoin, but also guarantee transaction information
similarly, a mathematical system contains 21 million mathematical problems, so we need to constantly seek the special solution of each mathematical problem through a huge amount of calculation. In addition, the special solution is unique
mining can not only increase the supply of bitcoin money, but also protect the security of bitcoin transactions and prevent fraulent transactions. In terms of process, bitcoin network is a point-to-point payment system, and anyone can trade through the transaction program
in order to ensure that the transaction process is truthfully recorded, the role of "miner" is required to be responsible for recording bitcoin transaction information. The time interval is 10 minutes. The best recorded transaction records among miners will be packaged and stored in a new block, and the corresponding miners will also receive a certain amount of bitcoin rewards
2. The mining process is extremely complex, which is beyond human power
the specific process is as follows. When a miner listens to the transaction, he will first verify the transaction information. The verified transactions will be recorded by miners and stored in their own database. There may be thousands of miners in the world doing the same thing, but every ten minutes, only one miner has the right to create a new block, so that the transaction information recorded by himself can be recognized and stored permanently
next, miners need to fight for the right to keep accounts. This is a competition of computing power. The core of this competition is to use computers to complete a large number of calculation tasks and find a super difficult random number. This random number is the special solution of the equation mentioned in the first paragraph. The miner who calculates the correct random number first wins. According to the rules of the game, the probability of a miner getting the accounting right is directly proportional to the proportion of his computing power in the total computing power of the whole network. In other words, the probability of finding the random number is equivalent to throwing out 100 million dice, and the total number of dice is less than 150 million. Therefore, mining requires a large number of computers, installation of specific algorithm software, repeated operation day and night, not human
3. Bitcoin mining is actually "villagers' bookkeeping"
maybe some netizens still don't understand, let's take an example. In a village, the villagers often borrow money from each other, even if they write a written document, there is a risk of default. Then, every time there is a loan behavior in the village, we will use the village trumpet to inform everyone that all the villagers (miners) will record all the transaction records in their own account books.
1. Mining can not only proce bitcoin, but also guarantee transaction information
similarly, a mathematical system contains 21 million mathematical problems, so we need to constantly seek the special solution of each mathematical problem through a huge amount of calculation. In addition, the special solution is unique
mining can not only increase the supply of bitcoin money, but also protect the security of bitcoin transactions and prevent fraulent transactions. In terms of process, bitcoin network is a point-to-point payment system, and anyone can trade through the transaction program
in order to ensure that the transaction process is truthfully recorded, the role of "miner" is required to be responsible for recording bitcoin transaction information. The time interval is 10 minutes. The best recorded transaction records among miners will be packaged and stored in a new block, and the corresponding miners will also receive a certain amount of bitcoin rewards
2. The mining process is extremely complex, which is beyond human power
the specific process is as follows. When a miner listens to the transaction, he will first verify the transaction information. The verified transactions will be recorded by miners and stored in their own database. There may be thousands of miners in the world doing the same thing, but every ten minutes, only one miner has the right to create a new block, so that the transaction information recorded by himself can be recognized and stored permanently
next, miners need to fight for the right to keep accounts. This is a competition of computing power. The core of this competition is to use computers to complete a large number of calculation tasks and find a super difficult random number. This random number is the special solution of the equation mentioned in the first paragraph. The miner who calculates the correct random number first wins. According to the rules of the game, the probability of a miner getting the accounting right is directly proportional to the proportion of his computing power in the total computing power of the whole network. In other words, the probability of finding the random number is equivalent to throwing out 100 million dice, and the total number of dice is less than 150 million. Therefore, mining requires a large number of computers, installation of specific algorithm software, repeated operation day and night, not human
3. Bitcoin mining is actually "villagers' bookkeeping"
maybe some netizens still don't understand, let's take an example. In a village, the villagers often borrow money from each other, even if they write a written document, there is a risk of default. Then, every time there is a loan behavior in the village, we will use the village trumpet to inform everyone that all the villagers (miners) will record all the transaction records in their own account books.
2. Bitcoin is a virtual currency, not a math problem
3. The so-called calculation specific mathematical problem (mining) is actually generating a block (a mechanism used to maintain the security of bitcoin system). The nature of cryptography involved in it makes it more and more difficult to calculate.
this calculation has nothing to do with other distributed computing projects, but is only used for internal calculation, The calculations do when mining are internal to bitcoin and not related to any other distributed computing projects. They serve the purpose of securing the bitcoin network, which is useful
this calculation has nothing to do with other distributed computing projects, but is only used for internal calculation, The calculations do when mining are internal to bitcoin and not related to any other distributed computing projects. They serve the purpose of securing the bitcoin network, which is useful
4.
Different heights have different horizons. To understand this problem, we need to know what the value of bitcoin is? There is no meaning of existence
at the beginning, students all said that they wanted to learn from scientists to invent and create to serve human beings, but did they ever know that the so-called scientists were also intriguing and never tired of practicing
5. The common calculation problems of retaining wall are as follows
1. Considering the soil viscosity
when the soil is cohesionless, the Rankine earth pressure theory or Coulomb earth pressure theory we have learned can meet the requirements, and the error is within the allowable range
when the soil is cohesive, the calculation error of Coulomb passive earth pressure theory is larger than that of Rankine passive earth pressure theory. Therefore, we can calculate the earth pressure by the standard method or the equivalent internal friction angle method
1) calculate the earth pressure by the standard method
code for design of building foundation (GB 50007) puts forward a kind of earth pressure calculation formula which can be applied to all kinds of soil and linear boundary conditions. The general form of the formula is applicable to the case of cohesive fill and uniform load on the surface of fill under Coulomb condition< br />Ea= ψ c1/2 γ Where H? Ka ψ C -- active earth pressure coefficient
2) equivalent internal friction angle method to calculate earth pressure
if the back of retaining wall is inclined and rough, and the filling surface is inclined and cohesive soil, the equivalent internal friction angle method is commonly used to calculate earth pressure in engineering
(1) according to the principle of shear strength, the shear strength of cohesive soil:
τ f= σ tan ψ＋ C
equivalent shear strength:
τ f= σ tan ψ In formula D ψ D -- equivalent internal friction angle °)， The cohesive force C of cohesive soil is included
we can get: σ tan ψ＋ c= σ tan ψ D
so there are: ψ D=arctan(tan ψ+ c/ σ)
in the above formula σ It is the average normal stress on the sliding surface. In fact, it is usually replaced by the self weight stress at the action point of the resultant earth pressure σ= 2/3 γ h. So it has a certain error.
1. Considering the soil viscosity
when the soil is cohesionless, the Rankine earth pressure theory or Coulomb earth pressure theory we have learned can meet the requirements, and the error is within the allowable range
when the soil is cohesive, the calculation error of Coulomb passive earth pressure theory is larger than that of Rankine passive earth pressure theory. Therefore, we can calculate the earth pressure by the standard method or the equivalent internal friction angle method
1) calculate the earth pressure by the standard method
code for design of building foundation (GB 50007) puts forward a kind of earth pressure calculation formula which can be applied to all kinds of soil and linear boundary conditions. The general form of the formula is applicable to the case of cohesive fill and uniform load on the surface of fill under Coulomb condition< br />Ea= ψ c1/2 γ Where H? Ka ψ C -- active earth pressure coefficient
2) equivalent internal friction angle method to calculate earth pressure
if the back of retaining wall is inclined and rough, and the filling surface is inclined and cohesive soil, the equivalent internal friction angle method is commonly used to calculate earth pressure in engineering
(1) according to the principle of shear strength, the shear strength of cohesive soil:
τ f= σ tan ψ＋ C
equivalent shear strength:
τ f= σ tan ψ In formula D ψ D -- equivalent internal friction angle °)， The cohesive force C of cohesive soil is included
we can get: σ tan ψ＋ c= σ tan ψ D
so there are: ψ D=arctan(tan ψ+ c/ σ)
in the above formula σ It is the average normal stress on the sliding surface. In fact, it is usually replaced by the self weight stress at the action point of the resultant earth pressure σ= 2/3 γ h. So it has a certain error.
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