More than 51
Publish: 2021-03-29 03:10:14
1. < UL >
this is mainly e to the 51% attack, because before some of the world's well-known mines, e to the low rate and convenient use, many miners went to those large mines to mine. As a result, the computing power of the mines soared, approaching or even exceeding 51% of the global computing power many times
bitcoin community has also raised a big discussion about 51% attack for many times,. The mine pool operators also called on the miners to move to other mines in a responsible manner, and finally 51% of the attacks were solved. Many of China's miners have moved to fish ponds
most of the new miners have joined the fish pond because they don't know about the global mine ponds, and many of the previous mines have died e to poor management
2. In fact, people will not let such a thing happen, because once someone controls 51% of the computing power of the whole network, the security and non tamperability of the system will be invalid, then the decentralization system of bitcoin will collapse, and the price of bitcoin will plummet or even return to zero, which is bad news for the participants of the whole network. Therefore, we will spontaneously control the distribution of computing power in the whole network, so as not to let one company dominate. Even when many people find that the computing power of a certain mine is too large, they will take the initiative to withdraw from the mine. Now the most powerful mining pool in the whole network accounts for about 25% of the whole network.
3. How to improve the ability of mathematical calculation
first, the improvement of the ability of calculation requires the study of hard theories and rules.
the correct operation must be based on a thorough understanding of calculation theory. The calculation theory in students' mind is clear and the rules are firmly remembered. When doing four calculation problems, it can be carried out in an orderly way. There are two mistakes in integer multiplication, 25 times 3 equals 95, 24 times 5 equals 100, which typically reflects that students do not have a thorough understanding of multiplication theory in the process of learning arithmetic, and how to deal with the number of multiplication carry is relatively vague. Furthermore, divisor is a decimal division in the two wrong cases (1). 44 divided by 1. 8 equals 8, 11. 2 divided by 0.05 equal to 22.4) also shows that the students' understanding of the law is not deep enough
to understand the meaning of the order and operation law, the operation order refers to the operation of the same level from left to right. In the formula without brackets, if there are addition, subtraction, multiplication and division, multiplication and division should be calculated first, then addition and subtraction; If you have brackets, you should first count the ones in the brackets, and then count the ones in the brackets. Primary school textbooks mainly talk about the law of exchange and combination of addition, and a property of subtraction: "subtracting the sum of two numbers from a number is equal to subtracting two addends from the number in turn." And the commutative law, associative law and distributive law of multiplication. These laws are applicable to the operation of integers, decimals and fractions at the same time, and are widely used. In the two wrong examples [327 - (27 + 75) = 375, 87 times 2 divided by 87 times 2 = 1], both show the students' wrong understanding of the calculation law and the operation law< Second, the improvement of computing power needs to pass, understand and master basic knowledge. In order to get the calculation results, students should first consider what mathematical concepts, operation laws, operation properties, operation rules and calculation formulas to use. Therefore, fully understanding and mastering these basic knowledge determines whether they have the ability of calculation. For example, if students want to have the ability to calculate four items of scores, they must first understand the meaning and nature of scores, understand and master the basic knowledge and corresponding basic skills such as general score, approximate score, the interaction between score and false score. Only when the relevant basic knowledge is explained clearly and the students really master it, the students will not make mistakes in calculation. Compared with the lower grades, the basic knowledge of the higher grades is more abundant. Therefore, we must not rush for success in teaching. We should help students start from sorting out the basic knowledge they have learned, use the transfer, and continue to deepen. For example, when teaching the addition of fractions with different denominators, first ask the students to answer the meaning of addition, and they will know that it is the operation of combining two numbers (or more numbers) into one number. Next, let the students observe and find that the fractions with different denominators and the units of fractions are different, and they can't add directly. After understanding this, they can guide the students to use the knowledge of general division to "turn differences into similarities", So the problem is transformed into the addition of fractions with the same denominator< Third, the improvement of calculation ability needs excellent oral calculation ability.
the new curriculum standard points out: "the basic and developmental nature of mathematics should be highlighted in the compulsory ecation stage." As for the ability of oral calculation, it is the basis of learning mathematics, and the level of oral calculation ability has an extremely important impact on students' basic calculation ability; The training of oral arithmetic is helpful to cultivate students' keen observation; It is helpful to cultivate students' comprehensive thinking ability; It is helpful to cultivate students' quick reaction ability; It is helpful to the cultivation of students' innovative consciousness. How to train the ability of oral arithmetic is an important subject worthy of discussion and research. Teaching practice tells us that it is very necessary to train students' oral arithmetic ability, and we should pay enough attention to it< Fourth, the improvement of computing ability needs to cultivate students' good computing habits.
to improve students' computing ability, we must pay attention to the cultivation of good computing habits< Make students form the habit of proofreading carefully
2. Students are required to see each data and operation symbol clearly, determine the operation order, and choose a reasonable operation method
3. Make students form the habit of careful calculation and standardized writing. Students are required to write neatly, with correct format, correct handwriting, no scribble, no alteration, and keep their homework neat and beautiful< 4. Make students form the habit of estimation and self-conscious checking. Give them the method of checking calculation and estimation, and take checking calculation as an important part of the calculation process to carry out strict requirements, advocating the use of estimation to check the correctness of the answers
5. Make students form the habit of mutual inspection. When a problem has been initially calculated, it can't be calculated completely. It's inevitable for students to make some mistakes in calculation, which requires students to check carefully
6. Be good at drafting.
first, the improvement of the ability of calculation requires the study of hard theories and rules.
the correct operation must be based on a thorough understanding of calculation theory. The calculation theory in students' mind is clear and the rules are firmly remembered. When doing four calculation problems, it can be carried out in an orderly way. There are two mistakes in integer multiplication, 25 times 3 equals 95, 24 times 5 equals 100, which typically reflects that students do not have a thorough understanding of multiplication theory in the process of learning arithmetic, and how to deal with the number of multiplication carry is relatively vague. Furthermore, divisor is a decimal division in the two wrong cases (1). 44 divided by 1. 8 equals 8, 11. 2 divided by 0.05 equal to 22.4) also shows that the students' understanding of the law is not deep enough
to understand the meaning of the order and operation law, the operation order refers to the operation of the same level from left to right. In the formula without brackets, if there are addition, subtraction, multiplication and division, multiplication and division should be calculated first, then addition and subtraction; If you have brackets, you should first count the ones in the brackets, and then count the ones in the brackets. Primary school textbooks mainly talk about the law of exchange and combination of addition, and a property of subtraction: "subtracting the sum of two numbers from a number is equal to subtracting two addends from the number in turn." And the commutative law, associative law and distributive law of multiplication. These laws are applicable to the operation of integers, decimals and fractions at the same time, and are widely used. In the two wrong examples [327 - (27 + 75) = 375, 87 times 2 divided by 87 times 2 = 1], both show the students' wrong understanding of the calculation law and the operation law< Second, the improvement of computing power needs to pass, understand and master basic knowledge. In order to get the calculation results, students should first consider what mathematical concepts, operation laws, operation properties, operation rules and calculation formulas to use. Therefore, fully understanding and mastering these basic knowledge determines whether they have the ability of calculation. For example, if students want to have the ability to calculate four items of scores, they must first understand the meaning and nature of scores, understand and master the basic knowledge and corresponding basic skills such as general score, approximate score, the interaction between score and false score. Only when the relevant basic knowledge is explained clearly and the students really master it, the students will not make mistakes in calculation. Compared with the lower grades, the basic knowledge of the higher grades is more abundant. Therefore, we must not rush for success in teaching. We should help students start from sorting out the basic knowledge they have learned, use the transfer, and continue to deepen. For example, when teaching the addition of fractions with different denominators, first ask the students to answer the meaning of addition, and they will know that it is the operation of combining two numbers (or more numbers) into one number. Next, let the students observe and find that the fractions with different denominators and the units of fractions are different, and they can't add directly. After understanding this, they can guide the students to use the knowledge of general division to "turn differences into similarities", So the problem is transformed into the addition of fractions with the same denominator< Third, the improvement of calculation ability needs excellent oral calculation ability.
the new curriculum standard points out: "the basic and developmental nature of mathematics should be highlighted in the compulsory ecation stage." As for the ability of oral calculation, it is the basis of learning mathematics, and the level of oral calculation ability has an extremely important impact on students' basic calculation ability; The training of oral arithmetic is helpful to cultivate students' keen observation; It is helpful to cultivate students' comprehensive thinking ability; It is helpful to cultivate students' quick reaction ability; It is helpful to the cultivation of students' innovative consciousness. How to train the ability of oral arithmetic is an important subject worthy of discussion and research. Teaching practice tells us that it is very necessary to train students' oral arithmetic ability, and we should pay enough attention to it< Fourth, the improvement of computing ability needs to cultivate students' good computing habits.
to improve students' computing ability, we must pay attention to the cultivation of good computing habits< Make students form the habit of proofreading carefully
2. Students are required to see each data and operation symbol clearly, determine the operation order, and choose a reasonable operation method
3. Make students form the habit of careful calculation and standardized writing. Students are required to write neatly, with correct format, correct handwriting, no scribble, no alteration, and keep their homework neat and beautiful< 4. Make students form the habit of estimation and self-conscious checking. Give them the method of checking calculation and estimation, and take checking calculation as an important part of the calculation process to carry out strict requirements, advocating the use of estimation to check the correctness of the answers
5. Make students form the habit of mutual inspection. When a problem has been initially calculated, it can't be calculated completely. It's inevitable for students to make some mistakes in calculation, which requires students to check carefully
6. Be good at drafting.
4.
Bitcoin is a kind of network virtual electronic currency, and its price has experienced roller coaster like ups and downs. It has no physical support, to put it bluntly, a string of computer code. Personally, I think this is a very unreliable thing. The Internet bubble is very big. In November 2013, the price of bitcoin once reached a high level of 8000 yuan / piece. Subsequently, the central bank, together with five ministries and commissions, issued the notice on preventing bitcoin risks, and the price of bitcoin plummeted. Now the price of bitcoin is more than 2300 yuan / piece
Jingxuan finance didn't you send a lot of articles a few days ago. China is now investigating bitcoin. Crash
5. There is a binice digital trading platform with formal registration certificate, operation photo taking and supervision mechanism, safe access to gold and formal platform.
6. No visual inspection. Although the idea is good, if you can, then there will be hackers.
7. The so-called 51% attack is to take advantage of bitcoin's ability to use computing power as a competitive condition to cancel the payment transactions that have already taken place
if someone has mastered more than 50% of the computing power, he can find the random number needed for mining blocks faster than others, so he actually has the absolute effective right of which block
he can:
1. Modify his own transaction records, which enables him to make double payments
2. Prevent the block from confirming some or all of the transactions
3. Prevent some or all of the miners from mining into any effective block
if someone has mastered more than 50% of the computing power, he can find the random number needed for mining blocks faster than others, so he actually has the absolute effective right of which block
he can:
1. Modify his own transaction records, which enables him to make double payments
2. Prevent the block from confirming some or all of the transactions
3. Prevent some or all of the miners from mining into any effective block
8. Bitcoin cash will not have 51% computing power attack. In theory, 51% computing power attack exists, but in practice, it is difficult to work. The reasons are as follows: at present, no single miner can account for more than 50% of the whole BCC network; 51% attack is a kind of technical activity, which is difficult to operate; The cost and benefit of 51% attack are asymmetric, and 51% attack will lead to double spending of transactions. However, most of the trading platforms have implemented strict real name authentication mechanism, which can not be realized in time; Once a miner has the ability to launch a 51% attack, supporters of other large blocks will switch their computing power to Bcc to prevent the occurrence of 51% attack; 51% of attacks will cause temporary confusion on the network, but it is not fatal, and will make the attacker become infamous.
9. Gemstones can be obtained by mining. There are nine colors of jewels: red, orange, yellow, green, green, blue, purple, black and white. Except for black and white gemstones, other gemstones can be excavated in Taoyuan Village and other countries' mines. Qin: Ruby Zhao state: Orange Ruby Chu state: Topaz Yan state: Emerald Qi: sapphire Korea: sapphire. Black and white gemstones can be obtained from Luoyi mine. It has the following functions: synthesis of seven color gem, synthesis of night pearl and inlay of seven color gem. The synthesis of seven color gemstones needs seven colors of red, orange, yellow, green, cyan, blue and purple and 1 million yuan of money; To synthesize a night pearl, we need red, orange, yellow, green, green, blue, purple, black and white gemstones and 2 million yuan of money; A wedding ring inlaid with seven color gems needs a wedding ring, seven color gems and a million yuan of money.
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