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do you remember what the consensus mechanism of bitcoin is? The consensus mechanism of bitcoin is pow. To put it simply, the more work you do, the higher the amount of computation you pay, the more likely you will be the first to find the correct hash value, and the more likely you will be rewarded with bitcoin
however, there are some defects in the pow of bitcoin, that is, it is too slow to process transactions, and miners need to constantly collide hash values through calculation, which is costly and inefficient. Friends who are interested in blockchain knowledge should see such a saying:
in order to make up for the deficiency of bitcoin, Ethereum has proposed a new consensus mechanism, called POS (this is the abbreviation of English, which means "proof of equity", also translated into "proof of equity")
POS simply means the same as its literal meaning: equity, equity. The more currency you hold, the more equity you have, the higher your equity
Ethereum's POS means that the more money you hold, the longer you hold it, the less difficult it will be to calculate and the easier it will be to mine
in the initial setting of Ethereum, Ethereum hopes to build a relatively stable system by using POW in the early stage, then graally adopt POW + POS, and finally completely transition to POS. So, it's true that the consensus mechanism of Ethereum is POS, but POS is only a plan or goal at the beginning of Ethereum's release. At present, Ethereum has not yet transitioned to POS, and the consensus mechanism adopted by Ethereum is still pow, that is, the pow of bitcoin, but it is slightly different from the pow of bitcoin
the amount of information here is a bit large,
the first information point is that the consensus mechanism currently adopted by Ethereum is also pow, but it is slightly different from the pow of bitcoin. So, what's the difference between the pow of Ethereum and bitcoin: in short, the mining difficulty of Ethereum can be adjusted, but the mining difficulty of bitcoin can't be adjusted. Just like our college entrance examination, because the teaching situation and the number of students in different provinces are not the same, so the college entrance examination is divided into national papers and provincial independent proposition
Ethereum said that I am in favor of the topic by region. Bitcoin said: No, it must be the same volume in the whole country. The difficulty is the same for everyone
the popular explanation is that bitcoin uses computer computing power to do a lot of hash collisions, enumerate various possibilities to find a correct hash value. The Ethereum system has a special formula to calculate the difficulty of each block. If a block is verified faster than the previous block, Ethereum protocol will increase the difficulty of the block. By adjusting the block difficulty, the time needed to verify the block can be adjusted
according to the Ethereum protocol, the dynamic adjustment method of difficulty is to make the time interval of creating new blocks in the whole network 15 seconds, and the network uses 15 seconds to create blockchain. In this way, because the time is too fast, the synchronization of the system is greatly improved, and it is difficult for malicious participants to launch 51% (that is, more than half) of the computing power to modify historical data in such a short time
the second information point is: in the initial setting of Ethereum, we hope to achieve the transition from POW to
POS through phased upgrade
dating back to 2014, at the beginning of Ethereum's launch, the team announced that the launch of the project would be divided into four stages, namely, Froniter, homestead, metropolis and serenity. In the first three stages, the consensus mechanism adopts pow (workload proof mechanism), and in the fourth stage, it switches to POS (equity proof mechanism)
on July 30, 2015, the first phase "frontier" of Ethereum was officially released. This phase is only suitable for developers. Developers can write smart contracts and decentralized application DAPP on Ethereum network, and miners begin to enter Ethereum network to maintain network security and get Ethereum coins. The leading-edge version is similar to the beta version, proving whether the Ethereum network is reliable or not
on March 14, 2016, Ethereum entered the second stage of "homeland". In this stage, Ethereum provides the wallet function, so that ordinary users can easily experience and use Ethereum. There is no obvious technology improvement in other aspects, but it shows that Ethereum network can run smoothly
in September 2017, Ethereum has reached the third stage of "metropolis"“ "Metropolis" is composed of Byzantine and Constantinople. The goal of this stage is to introce the hybrid chain mode of POW and POS, so as to prepare for the smooth transition from POW to POS. This is the latest popular "Ethereum Constantinople upgrade". In the Constantinople upgrade, Ethereum will make some changes to the underlying protocols and algorithms to lay a good foundation for the implementation of POW and
POS
how much reward will Ethereum get for mining? Miners who win the block creation competition will get the following income:
1. Static reward, 5 ethereums
2. The fuel cost in the block, i.e. gas, we talked about in the last issue
3. As a part of the block, it includes the extra reward of "Uncle block". Uncle is uncle of uncle, and each uncle block can get 1 / 32 of the mining reward as a reward, that is, 5 times 1 / 32, which is equal to 0.15625 ethereums. Here, let's briefly explain the concept of "TERT block". The concept of "TERT block" was proposed by Ethereum. Why should we introce the concept of TERT block? This also starts with bitcoin. In the bitcoin protocol, the longest chain is considered absolutely correct. If a block is not part of the longest chain, it is called a "orphan block". An isolated block is a block, which is also legal, but it may be found later, or the network transmission is slower, and it does not become part of the longest chain. In bitcoin, the solitude is meaningless and will be discarded later, and the miners who find the solitude will not receive mining related rewards
however, Ethereum does not think that isolated blocks are worthless, and Ethereum system will give rewards to miners who find isolated blocks. In Ethereum, isolated blocks are called "Uncle blocks", which can contribute to the security of the main chain. Ethereum's ten second block interval is too fast, which will rece the security. By encouraging the use of tertiary blocks, the main chain can obtain more security guarantees (because the isolated block itself is legal). Moreover, paying the tertiary block can also stimulate the miners to actively mine and actively use tertiary blocks. Therefore, Ethereum thinks that it is valuable.
bookkeeping
because bookkeeping is a reward, each time you can add a certain number of bitcoin for yourself, so everyone is competing for bookkeeping, which of course leads to a problem: when there is inconsistency in bookkeeping, the system introces workload proof to solve the problem, and the rules are as follows:
1. In a period of time, only one person can succeed in bookkeeping
2. Obtain the unique bookkeeping right by solving the cryptography problem
3. Other nodes the bookkeeping results
but before the workload proof, The accounting node will do the following preparatory work:
1. Collect the original transaction information that has not been recorded in the broadcast
2. Check whether the payment address in each transaction information has enough balance
3. Verify whether the transaction has the correct signature
4. Package and record the verified transaction information
5. Add a reward transaction: add 12.5 to your address Bitcoin
if you succeed in competing for bookkeeping rights, you can get a reward of 12.5 bitcoin
workload proof
the hash value of the previous block and the current account page information will be hashed together as the original information in each bookkeeping. In order to ensure that only one person can keep accounts around 10 minutes, we have to improve the difficulty of keeping accounts. The results of hash must start with several zeros. In order to satisfy the condition, hash is to introce a random number variable
denoted by pseudo code:
1. Hash (last hash value, transaction record set) = 456635bcd
2. Hash (last hash value, transaction record set, random number) = 0000afd635bcd
if you change part of the original information of hash, the hash value will also change continuously. Therefore, when you run hash, the value of random number will change continuously, A random number can always be found so that the result of hash starts with several zeros. The node that finds the random number first obtains the unique bookkeeping right
verification
after the node successfully finds the hash value, it will broadcast and package the block to the whole network immediately, and the node of the network will verify it after receiving the broadcast. If the verification is passed, it indicates that a node has successfully decrypted, it will not compete for the current block, but will choose to accept the block and record it in its own account book for the next round of competitive guessing. Only the fastest decrypted block in the network will be added to the ledger, and other nodes will to ensure the uniqueness of the whole ledger
If a node has cheating behavior, it will cause the node of the network to fail the verification, give up its packaged block directly, and cannot be recorded in the general ledger, then the consumption cost of the cheating node will be in vain. Therefore, miners consciously abide by the consensus protocol of bitcoin system, and ensure the security of the whole system
it's like you go to the construction site to move bricks. After moving bricks for one day, the contractor asks you how can you prove that you move bricks for one day?
1. The proction of clowns
the proction mechanism of clowns can be divided into two kinds, one is the official output, the other is the breeding output between two clowns
one official clown is proced every 15 minutes, and the total number is only 50000. At certain times, the official will also release some strange clowns with special shapes. The price of the original clown is the average of the prices of the last five clowns in the market
two clowns of different genders can reproce in the breeding center of the market. In each breeding pair, one clown who plays the role of father can receive the breeding fee paid by the other party (maternal Master). After breeding, there is a certain recovery period, which is related to the clown's genes. The clown in the role of mother will have a period of pregnancy, and she will not be able to breed with other clowns until she gives birth to her baby. There is no limit to the number of breeding times of each etheric clown, but the recovery period and pregnancy period will increase with the number of breeding times< Each clown's appearance is determined by the tamperable genes stored in the smart contract, and each gene is unique, so each clown is unique
the appearance of a clown is composed of eight parts, each part of which can be divided into ordinary and rare attributes. The number of rare attributes is less than that of ordinary attributes, which makes the clown with rare attributes more precious
the appearance of a clown born in breeding is closely related to his parents and the genetic genes carried by his parents. The offspring have a high probability of inheriting the shape of some parts of his parents, so that their parents' good genes can be inherited, and it is possible to mutate and become a completely different clown from his parents
3. Clown trading
etheric clown can be directly used for trading
sell: users can choose clowns to be auctioned in the market, and they can sell their own clowns. When selling, users need to set the highest starting price, the lowest acceptance price and the auction time. The Dutch auction is adopted in the auction. During the auction time, the highest price set by the seller is graally transferred to the lowest price. If the owner is not willing to sell at a low price, a longer auction time can be set or the clown can be sold off the shelves
buy: the buyer selects the clown on sale in the market and pays ether to buy the clown he likes. When the buyer purchases, the transaction will be concluded at the auction price at the current time point. If you have a favorite clown, but feel that the price is not suitable for the time being, and want to pay more attention, you can collect the clown after you like it. Later, we can understand the dynamic of the clown through "my attention"< There are four kinds of clown attribute values: growth value, strength value, agility value and wisdom value. Generation 0 clowns get the value of each attribute randomly, and the non generation 0 clowns are mainly inherited
attribute values can be changed by eating food
after the clown's growth value reaches the requirement (100 points), he can go to the factory to earn money (ETH). Different kinds of factories need different clowns. Dream college needs the wisdom of every working clown. Clowns with more than 800 points of wisdom go to Dream Academy of Sciences to work, and their income can get bonus. If a clown with less than 300 wisdom goes to work, his income will be reced to
a part-time job will consume physical strength. The total physical strength is 120 points. It consumes 1 point every 12 minutes and can work up to 24 hours. During the period of not working, physical strength can be recovered, a little every 8 minutes
when the time reaches 0 o'clock or the clown's physical exertion is completed, the clown's work income will be settled according to the actual working hours at 0 o'clock every day. When every 12 minutes is a work, less than 12 minutes will not be counted
5. Clown food and feeding
owners can buy spinach, beef, carrots, walnuts and other food through the mall to feed clown pets
the price of food is related to the selling price of original clowns on the platform the day before. So the owners can hoard some food when the price of food is low
feeding spinach is helpful to growth value, beef corresponds to clown pet's strength value, carrot corresponds to agility, walnut corresponds to wisdom
the clown can only eat one food a day. We suggest that spinach should be fed in the early stage to meet the working conditions as soon as possible, and then according to the natural properties of clown in the later stage. When working, choose the type of factory with the highest attributes to work.
if the operation is proper, the mining company you invest in will continue to operate, and you may get the expected income
if the operation is improper, the mining company you invest in will go bankrupt or encounter other problems, and your investment will be more dangerous
so be cautious in mining, and there are more pits
the law does not specify that sick leave must be certified by the hospital
but in practical work, to ask for paid sick leave, and in order to avoid the abuse of paid sick leave, according to the specific situation of the employer, we usually need to provide some certificates:
1. Sick leave certificate issued by the hospital. The certificate should be signed by the attending doctor and stamped with the official seal of the hospital
2. Or other similar certificates within the employer
If an employee asks for sick leave at work, his salary can not be dected generally. When an employee asks for sick leave, the employer shall determine the wage standard of the employee ring sick leave based on 60% to 100% of the employee's normal working time wage, and shall not be lower than 80% of the local minimum wage standard
extended data:
the specific contents are as follows:
(1) ring the treatment period of employees' illness or non work related injury, the enterprise shall pay the sick leave wage or disease relief fee according to the relevant regulations within the specified medical period. The sick leave wage or disease relief fee can be paid below the local minimum wage standard, but not less than 80% of the minimum wage standard
(2) except for the circumstances stipulated in Article 25 of the labor law, the employer shall not terminate the labor contract when the employee works ring the period of medical treatment, pregnancy, childbirth and lactation and when the term of the labor contract expires. The term of the labor contract shall automatically extend to the expiration of the period of medical treatment, pregnancy, childbirth and lactation(3) after the expiration of the medical treatment period, the employees who ask for long sick leave can continue to perform the labor contract if they can engage in the original work; If after the medical treatment period, they are still unable to engage in the original work or other work arranged by the unit, the labor appraisal committee shall conct the labor ability appraisal with reference to the appraisal standard for the degree of disability caused by instrial injury and occupational disease
According to the comprehensive inquiry network of the examination center of the Ministry of ecation, if you always report errors when you submit the order for the replacement of CET4 grade, it is recommended that you directly apply for the certificate of achievement, because: the current CET certificate report sheet will not be reissued after it is lost or damaged, but the certificate of CET4 grade can be handled according to the regulations
CET transcripts will not be reissued if they are lost. Candidates can apply for CET score certification in June 2005 and after. The specific methods are as follows: reissue CET (including small languages) in June 2005 and after, and oral test score certification in the second half of 2014 to the first half of 2016. Candidates can log in to China Ecation Examination website to handle it by themselves, Website: China Ecation Examination Network
CET includes CET-4 and CET-6, Japanese CET-4 and CET-6, German CET-4 and CET-6, Russian CET-4 and CET-6 and French CET-4. CET has oral test, namely CET-4 and CET-6 oral test, which is abbreviated as "CET-SET". At present, only English subjects have oral test for corresponding subjects, namely cet-set4 and cet-set6