Blockchain takes up a lot of storage space

1. Now there are potential solutions. More nodes help make bitcoin network faster, healthier and more resistant to censorship. Decentralization is one of the core principles of blockchain based cryptocurrency. Fortunately, there are more potential solutions to solve this problem, which can make it easier for users to run a full node

first of all, the cost of hard disk has dropped from the lowest of US $0.025/gb in 2017 to US $0.15/gb, a 40% drop in three years. If this rate of decline continues, then by 2022, the decline rate of hard disk home will be faster than the growth rate of bitcoin, because over time, hosting a full node will be more economical
however, there are some technical solutions to solve this problem, which can rece the storage burden of the whole node. One of the most common solutions is light node. These nodes use a simplified payment verification method to verify transactions. Users only need to download a small part of the blockchain, but they need to rely on the third-party full node hosting the whole blockchain.

2. const SHA256 = require(crypto-js/SHA256);< br />class Block{
constructor(index,timestamp,data,previousHash='&# 39;)< br />{
this.index=index;< br />this.timestamp=timestamp;< br />this.data=data;< br />this.previousHash=previousHash;< br />$this.hash=this.calculateHash();< br />}

calculateHash(){
return SHA256(this,index+this.previousHash+this.timestamp+JSON.stringify(this.data)).tostring();< br />}
}
class Blockchain{
constructor(){
this.chain=[this.createGenesisBlock()];<
}
/ / create a generated information block
creategenesis block() {
return new block (0, & quot; 01/01/2019",& quot; Genesis block", 0);
/ / the date is the user's data. In fact, it is the hash value obtained by adding several values together. Here, the information is encrypted and the picture is encrypted. Then the data is still stored in the database, but all the data are hash values. To get this data, you must know the hash value of the previous data block. Then, if the hacker needs to crack all the nodes, the hash value is decrypted, Then all the blocks from the first node to the last node can be decrypted to get the real data. So the security of data stored in the blockchain depends on whether the data is encrypted. If the plaintext is not encrypted, then it is not a blockchain
}
/ / get the last block
getlatesblock() {
return this.chain [this.chain. Length-1]
}
/ / create block
addblock (newblock) {
newblock. Previoushash = this. Getlatesblock(). Hash< br />newBlock.hash=newBlock.calculateHash();< br />this.chain.push(newBlock);< br />}
}

3. In theory, blockchain technology is very powerful and can subvert all walks of life. But the ideal is full, the reality is backbone. Eight years after its birth, bitcoin soared from worthless to 8000 yuan, and then its price fell. During the period, after countless ups and downs, still strong to go on. The technology application of blockchain is also like this, from no one before to now, it has become the focus of an era. But there are not many successful applications. Bitcoin, Ethereum and decent are relatively successful, but they are still unable to be popularized.

4. The relationship between blockchain and big data storage is as follows:
first, data security: blockchain makes data flow "at ease"
with its trustworthiness, security and non tamperability, blockchain liberates more data. A typical case is used to illustrate how blockchain promotes the generation of big data for gene sequencing. Blockchain sequencing can use the private key to limit access rights, so as to avoid the legal restrictions on indivial access to gene data, and use distributed computing resources to complete the sequencing service at low cost. The security of blockchain makes sequencing an instrialized solution, realizing global scale sequencing, thus promoting the massive growth of data< Second, data open sharing: blockchain guarantees data privacy
the government has a large number of high-density and high-value data, such as medical data, population data, etc. The opening of government data is the general trend, which will have an inestimable impetus to the development of the whole economy and society. However, the main difficulty and challenge of data opening is how to open data while protecting personal privacy. Data desensitization technology based on blockchain can ensure data privacy and provide a solution for data opening under privacy protection. Data desensitization technology mainly uses hash processing and other encryption algorithms. For example, enigma based on blockchain technology can protect the privacy of data and eliminate information security problems in data sharing by computing data without accessing the original data. For example, employees of a company can safely open the path to access their salary information and jointly calculate the average salary within the group. Each participant can know his or her relative position in the group, but he or she knows nothing about the salaries of other members< The schematic diagram of data hash desensitization processing
3. Data storage: blockchain is a kind of database storage technology that can not be tampered with, full history, strong endorsement
blockchain technology, through all nodes in the network participate in the calculation together, and verify the authenticity of their information to achieve the consensus of the whole network, it can be said that blockchain technology is a specific database technology. So far, our big data is still in a very basic stage. The data based on the consensus of the whole network and the reliable blockchain data are tamperable and historical, which makes the quality of the data gain unprecedented strong trust endorsement, and also makes the development of the database enter a new era< Data analysis: blockchain ensures data security
data analysis is the core of realizing data value. In data analysis, how to effectively protect personal privacy and prevent core data leakage has become the primary consideration. For example, with the application of fingerprint data analysis and the popularization of genetic data detection and analysis, more and more people worry that once personal health data is leaked, it may lead to serious consequences. Blockchain technology can prevent this kind of situation through multi signature private key, encryption technology and secure multi-party computing technology. When the data is hashed and placed on the blockchain, the use of digital signature technology can enable those authorized people to access the data. The private key not only ensures the privacy of data, but also can be shared with authorized research institutions. The data is stored on the decentralized blockchain and analyzed without accessing the original data. It can not only protect the privacy of the data, but also provide it to the global scientific research institutions and doctors for sharing. As the basic health database of all mankind, it will bring great convenience to solve the sudden and difficult diseases in the future
v. data circulation: blockchain protects the rights and interests related to data
for valuable data assets of indivials or institutions, blockchain can be used to register them. Transaction records are recognized, transparent and traceable throughout the network, making clear the source, ownership, use right and circulation path of big data assets, which is of great value to data asset transaction
on the one hand, blockchain can break the threat of intermediary ing data, which is concive to the establishment of a trusted data asset trading environment. Data is a very special commodity, which is essentially different from ordinary commodities. It is mainly characterized by unclear ownership and "being owned after seeing and ing", which also determines that the traditional commodity intermediary transaction method can not meet the needs of data sharing, exchange and transaction. Because the intermediary center has the conditions and the ability to and save all the flowing data, it is extremely unfair to the data procers. This threat can not be eliminated only by commitment, and the existence of this threat has become a huge obstacle to the flow of data. Based on the decentralized blockchain, it can break the threat of ing data in the intermediary center and protect the legitimate rights and interests of data owners
on the other hand, blockchain provides a traceable path, which can effectively solve the problem of data right confirmation. Through multiple nodes participating in the calculation in the network, blockchain can participate in the calculation and recording of data together, and verify the effectiveness of their information. It can not only carry out information anti-counterfeiting, but also provide a traceable path. The transaction information of each block is strung together to form a complete detailed list of transactions. The context of each transaction is very clear and transparent. In addition, when people have doubts about the "value" of a block, they can easily trace back the historical transaction records, and then judge whether the value is correct, and identify whether the value has been tampered or recorded incorrectly
with the protection of blockchain, big data will naturally become more active
the tokens of crowdfunding projects on coin Ying China platform are all developed based on blockchain technology, and relevant information will be recorded on the blockchain.

5. Hello, of course.
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies. Blockchain is an important concept of bitcoin. It is essentially a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of information about bitcoin network transactions, Used to verify the validity of its information (anti-counterfeiting) and generate the next block. In fact, the original English version of bitcoin white paper [1] does not use the word blockchain, but uses the word chain of blocks. In the earliest Chinese translation of bitcoin white paper [2], chain of blocks was translated into blockchain. This is the earliest time when the Chinese word "blockchain" appeared.

6.

1. The "load" in dispatching is the electric quantity, unit: degree, also is kilowatt hour, kW & 8226; h;

load is not a constant value, but a variable value with time. Because the electrical equipment does not run at the same time, even at the same time, not all can reach the rated capacity. In addition, the working system of each electrical equipment is different, including long-term, short-term and repeated short-term

2. "Load" used in power flow calculation refers to the outgoing power flow of a node, which is the power

S=P+jQ

where p is active power

unit: W, kW, MW

q is reactive power, unit VaR, kvar, Mvar

s is complex power, unit VA, KVA, MVA

in design, if the capacity of each electrical equipment is simply added up as the basis for selecting conctor, cable section and electrical equipment capacity, the equipment will be under loaded, resulting in a waste of investment and non-ferrous metals; If it is too small, overload operation will occur

the result is either uneconomic, or overheating insulation damage and line loss increase, which will affect the safe operation of wires, cables or electrical equipment, and even cause fire accidents. Therefore, the load calculation is only close to the actual capacity

< H2 > extended data

the total load of power system is the sum of the total power consumed by all electrical equipment in the system; By adding the power consumed by instry, agriculture, posts and telecommunications, transportation, municipal administration, commerce and urban and rural residents, the comprehensive power load of power system can be obtained; The power of comprehensive power load plus network loss is the power that each power plant in the system should supply, which is called the power supply load (power supply) of power system; The power supply load plus the power consumed by each power plant itself (i.e. auxiliary power) is the power that should be generated by each generator in the system, which is called the generation load (generation capacity) of the system

the load is a random change, every time the electrical equipment starts or stops, the corresponding load will change, which can be found to have a certain regularity to some extent. For example, some loads change to a certain extent with seasons (summer and winter) and enterprise working system (one shift or shift operation). The regularity of its change can be described by load curve: the so-called load curve refers to the graph of active and reactive load changing with time of electrical equipment in a certain period of time, which constitutes active load curve (P) and reactive load curve (q) respectively

7. I choose Chinese currency! Low operation delay, idle can also save money mining EOS, very suitable.

8. Virtual currency does not belong to currency, because it is not a general equivalent and can only buy specific goods, which is more like shopping vouchers.

9. DGC is really unreliable. It's been 20 days since the withdrawal. I think it's really unreliable. Sorry to die

10. Blockchain technology is not omnipotent. At present, it is still in the stage of incompetence. Blockchain technology is not mature at present! It's too early to talk about the application of an immature technology all day long. Some Internet listed companies come out to talk about what blockchain technology breakthroughs they have made, how they plan to apply them, or what proct applications based on blockchain technology they have launched. In my opinion, most of them are pretentious and have no real use. At present, it is not to decide how to apply it, but to study and develop the technical reserve of blockchain. It's hard to do a good job of technical update by parroting!