Total number of blockchains

1.

From the perspective of technology and architecture, I will tell you my understanding of blockchain in common language

what is blockchain? In a word, blockchain is a storage system. To be more specific, blockchain is a distributed storage system without an administrator and each node has all the data

What are the common storage systems like

first, how to ensure high availability

the common storage system usually uses "rendancy" to solve the problem of high availability. As shown in the figure above, if the data can be copied into several copies and rendant to multiple places, high availability can be guaranteed. The data in one place is hung, and there is data in other places. For example, the master-slave cluster of MySQL is the same principle, and the raid of disk is also the same principle

two points need to be emphasized in this place are: data rendancy often leads to consistency problems

1. For example, in the master-slave cluster of MySQL, there is actually a delay in reading and writing, which means there is a inconsistency in reading and writing in a short period of time. This is a side effect of data rendancy

The second point is that data rendancy often reces the efficiency of writing, because data synchronization also consumes resources. If you add two slave libraries, the write efficiency will be affected. The common storage system is to use rendancy to ensure the high availability of data

so the second question, ordinary storage system, can write more

the answer is yes, for example, take this graph as an example:

in fact, MySQL can do a master-slave synchronization of al masters, master-slave synchronization of al masters, two nodes can be written at the same time. If you want to do a multi room multi live data center, in fact, multi room multi live data synchronization. What we should emphasize here is that multi-point writing often leads to the consistency problem of writing conflicts. Take MySQL as an example, suppose that the attribute of a table is self incrementing ID, then the data in the database is 1234 now. If one of the nodes writes and inserts a piece of data, it may become 5, and then these 5 pieces of data are synchronized to another master node, Before synchronization, if another write node inserts a piece of data, a piece of data with self incrementing ID of 5 will be generated. Then, after the generation, synchronize to another node, and the synchronized data will conflict with the two local 5's after it arrives, which will lead to synchronization failure and write consistency conflict. This problem will occur in the case of multi-point writing

how to ensure consistency in multi-point writing

the reform "Swan class" gives you more technical work

2. Blockchain mainly solves the trust and security problems of transactions, so it proposes four technological innovations to solve this problem:
(1) distributed ledger, that is, transaction bookkeeping is completed by multiple nodes distributed in different places, and each node records complete accounts, so they can participate in monitoring the legitimacy of transactions, At the same time, they can testify together
different from traditional distributed storage, the uniqueness of distributed storage of blockchain is mainly reflected in two aspects: one is that each node of blockchain stores complete data according to block chain structure, while traditional distributed storage generally stores data in multiple copies according to certain rules. Second, the storage of each node in the blockchain is independent and has the same status, which relies on the consensus mechanism to ensure the consistency of storage, while the traditional distributed storage generally synchronizes data from the central node to other backup nodes[ 8]
no single node can record the account data separately, so as to avoid the possibility that a single bookkeeper is controlled or bribed to record false accounts. In theory, unless all the nodes are destroyed, the accounts will not be lost, so as to ensure the security of the account data
(2) asymmetric encryption and authorization technology, the transaction information stored on the blockchain is public, but the account identity information is highly encrypted, which can only be accessed under the authorization of the data owner, thus ensuring the data security and personal privacy
(3) consensus mechanism is how to reach a consensus among all accounting nodes to determine the validity of a record, which is not only a means of identification, but also a means of preventing tampering. Blockchain proposes four different consensus mechanisms, which are suitable for different application scenarios and achieve a balance between efficiency and security
the consensus mechanism of blockchain has the characteristics of "the minority is subordinate to the majority" and "everyone is equal", in which "the minority is subordinate to the majority" does not completely refer to the number of nodes, but also can be the computing power, the number of shares or other characteristics that can be compared by computers“ "Everyone is equal" means that when the nodes meet the conditions, all nodes have the right to put forward the consensus results first, and then directly recognized by other nodes, and finally may become the final consensus results. Taking bitcoin as an example, the workload proof is adopted. Only when more than 51% of the accounting nodes in the whole network are controlled can a nonexistent record be forged. When there are enough nodes in the blockchain, this is basically impossible, thus eliminating the possibility of fraud.
(4) smart contract, which is based on these trusted and tamperable data, can automatically execute some pre-defined rules and terms. Take insurance as an example. If everyone's information (including medical information and risk occurrence information) is true and reliable, it is easy to carry out automatic claim settlement in some standardized insurance procts

3. Generally speaking, it must be a year when a large number of blockchain applications have sprung up. Now, blockchain is being developed all over the country. There is a SMIC blockchain service platform project initiated by Changsha high tech Zone, which is based on the blockchain + public service mode and is recruiting enterprises to join the chain. In the future, relevant enterprise affairs and government affairs can cooperate on the chain. It is also one of the key blockchain projects in Hunan Province.

4. Madame Curie is a great physicist. She was born in Poland and her real name is Mary. Because she married Pierre Curie, a young French scholar, she was later known as Madame Curie. Together with her husband, she discovered and confirmed the existence of radium. Now we want to tell you how the Curies discovered radium< In 1898, French physicist Antoine Henri Becquerel discovered that uranium bearing minerals can emit a mysterious ray, but he failed to reveal the mystery of this ray. Mary and her husband, Pierre Curie, worked together on the radiation. Under extremely difficult conditions, they separated and analyzed pitchblende, and finally found two new elements in July and December 1898

in memory of her motherland Poland, she named one element polonium and the other radium, which means "radioactive substance". In order to prepare pure radium compound, Marie cui7e (1867-1934) spent four years to extract 10 mg radium chloride from tons of pitchblende slag, and the relative atomic mass of radium was 225. This simple figure embodies the painstaking efforts and sweat of the Curies< In June 1903, Madame Curie received her doctor's degree in physics from the University of Paris with her doctoral dissertation in the study of radioactive substances. In November of the same year, the Curies were awarded the David gold medal by the Royal Society. In December, they won the 1903 Nobel Prize in physics with becoller< In 1906, Pierre Curie died in a car accident. This heavy blow did not make her give up her persistent pursuit. She enred her grief and redoubled her efforts to complete their beloved scientific cause. She continued her husband's lecture at the University of Paris and became the first female professor of the University. In 1910, her famous book on radioactivity was published. With Mou, she worked with others to analyze pure metal radium and determine its properties. She also measured the half lives of oxygen and other elements and published a series of important works on radioactivity. In view of the above achievements, she won the Nobel Prize in chemistry in 1911 and became the first great scientist to win the Nobel Prize twice in history<

the founder of radiation science, who has experienced the joys and sorrows of science, died of malignant anemia (leukemia) on July 4, 1934 e to years of hard work. She has dedicated her glorious life to the scientific cause of mankind< Before the Curie couple discovered radium, it was just known that there is a rare metal called uranium, which can emit penetrating rays, that is, X-rays. When Madame Curie knew the news, she immediately thought that there might be other substances with similar radioactivity as uranium. In order to confirm this conjecture, they began to do experiments

Mr. and Mrs. Curie have a small laboratory transformed from a storage room. This laboratory has no floor. It is cold in winter and hot in summer. There is only a stove with a broken chimney, four benches with uneven length and a worn-out blackboard in the room. They started their hard work in this laboratory

Mary observed a kind of pitchblende with instruments, and she thought that there was another element with stronger radioactivity in it, which was a new element that had not been found yet. She and her husband decided to find this element. They first called this new element "radium". To prove the existence of radium, they had to extract it from pitchblende. In order to save money, they didn't buy expensive pitchblende, they just bought a lot of pitchblende resie that has been refined uranium. There is a special refining equipment in the yard, but it has to withstand the hot sun in summer and freeze stiff in winter. In case of heavy rain, the two people have to move the machine to the house in a hurry

Mary and her husband devoted themselves to their work. Every day, they wear work clothes covered with lime and soil, stained with various liquids, watch the boiling minerals in the pot, and constantly stir them with iron bars in their hands. Soot and poisonous gas irritated their eyes and throat, making them very uncomfortable. This kind of work is arous and monotonous. In this way, it continues for one, two or three years, but radium still does not appear< However, Madame Curie said, "no, I will never give up. I believe we will succeed." They imagine that radium will have a beautiful color. When they are tired of work, they will sit together and talk about this new element radium, which makes them excited and excited
finally one day, radium, which Mary and Pierre thought about day after day, appeared

that night, when they got home, they couldn't sleep. Madame Curie felt a kind of uneasiness in her heart, so she stood up, took her husband and said, "go, shall we go there?"

"there" is their laboratory. They rushed to the laboratory in the moonlight, as if they heard radium calling them gently

the couple walked down the street, past factories, open spaces, past a residential area, and finally walked into their small laboratory< After the door was opened, Mary said softly, "honey, don't light the light! Don't we want radium to have a beautiful color? " Pierre nodded. "Well, let's see."

the room is dark. In the dark, there is a kind of glowing blue light. It jumps in the dark, like a firefly at night. Mary looked at the beautiful blue light and clenched Pierre's hand with excitement. She knew that they had succeeded. This beautiful light was the light from the mysterious element radium
after four years, the Curies overcame difficulties and confirmed the existence of radium. Many scientists didn't believe in radium, but now they have to admit it. They expressed their admiration for the Curies.

5.

Today, geometric car released the rendering of its new car geometric C, and put forward a new concept -- the new favorite of pure electric

Therefore, the new geometric platform means that geometric C may have a new electronic and electrical architecture, which means a lower level architecture with higher integration, higher computing power and higher openness, providing a lower level guarantee for subsequent OTA, joint development and "feeding"

■ driverless and 5g

according to the official news, geometric C will apply Geely's latest technological achievements in the field of driverless and carry Geely's self-developed "intelligent tracking driverless system". The system is the first domestic automatic driving technology that combines the car end, cloud end and field end, and will be equipped with 5g in the future to realize full road condition, full scene and seamless high-speed connection. It can turn on 100% independent parking function in outdoor and indoor multi scene. In the future, driverless scenes such as unmanned parking, unattended, and unattended express delivery will be constructed in stages to continuously evolve

well... It looks very powerful. If it can be realized, it can be called the comprehensive commercial use of 5g + Internet of things

based on my current knowledge and practical experience, I really can't imagine what "all road conditions, all scenes, seamless high-speed connection of automatic driving" and "100% autonomous parking" would look like. Because even Tesla, which is currently the leading company, can only drive automatically under specific road conditions (sometimes not very smart); The success rate of automatic parking is worrying. Every time I test this function, I'm more nervous than my subject 2

therefore, for geometry C's unmanned driving, I really hope it can make a big splash and hit Tesla in the face

Of course, it's meaningless to talk on paper. It's mules or horses. Let's take a walk! When we get the test drive, we will bring you detailed experience and evaluation in time. Please look forward to it

To sum up, geometric C is an electric vehicle with good appearance, smart mind and enough enrance; In addition, in terms of driverless and intelligent Internet, it seems to want to bring us unprecedented experience. I very much hope that it can become a pioneer or leader and a Chinese brand leading the world trend

this article comes from the author of car home, which does not represent the standpoint of car home

6. With the combination of 5g and robot technology, new consumer electronics procts are emerging. AI solves the problem of machine understanding the world and human-computer interaction. 5g expands the mobile boundary of the robot, and provides more computing power and storage space for the robot (cloud cooperative robot)< According to the IFR classification method, robots can be roughly divided into instrial robots and service robots. Traditional instrial robots are mainly used in automobile and parts, electronic manufacturing, metal and machinery, food processing and so on. Its main feature is to complete the specified action along the specified path according to the predetermined procere. How can AI / 5G enable robots

the application of AI Artificial Intelligence has given birth to service robots. Service robot covers a wide range, including medical, logistics, agriculture, commerce, civil and other aspects. Through the use of AI technology, through data collection, analysis and calculation, service robot can learn human behavior, understand human intention and cooperate with human< According to IFR calculation, the global robot market in 2017 reached US $23.2 billion, of which the instrial robot market reached US $14.7 billion, with 85 robots per 10000 people. The rest is the service robot market, with a market size of US $8.5 billion

by 2030, the robot market is expected to reach 102.8 billion US dollars, about 20% of the smartphone market. Service robots will reach US $56.1 billion, maintaining a compound annual growth rate of 16%, which is faster than that of instrial robots. After two years of rapid development in 2017 and 2018, the number and amount of financing in the artificial intelligence instry in 2019 showed a precipice like decline, capital concentrated in the head enterprises one after another, and the survival of small companies was difficult. Even the head companies have encountered obstacles on the way to listing, and the news of layoffs is constantly shrinking. From the external environment, everyone's life is not easy

cheetah global think tank believes that the future of artificial intelligence is not always full of flowers and applause. If artificial intelligence really wants to lead the next decade, it must be that practitioners abandon the flashy valuation, focus on procts, take root in technology, and strive for the realization of the scene overnight

pencil recommendation:

after two years of rapid development in 2017 and 2018, the number and amount of financing in the artificial intelligence instry will show a precipice like decline in 2019, capital will be concentrated in the head enterprises one after another, and small companies will have a hard time surviving. Even the head companies have encountered obstacles on the way to listing, and the news of layoffs is constantly shrinking. From the external environment, everyone's life is not easy

cheetah global think tank believes that the future of artificial intelligence is not always full of flowers and applause. If artificial intelligence really wants to lead the next decade, it must be that practitioners abandon the flashy valuation, focus on procts, take root in technology, and strive for the realization of the scene overnight<

source | cheetah global think tank

authors | Zhou Ting, pan Xinghan, Li Xin, Xiao Haiyan

report guidance | Han Jianqi, Zhou Ting

I. foreword

I. foreword

if you want to establish a biography for artificial intelligence, 2019 is destined to be a different year of seeking normality. Difficult and awkward, rooted and stick to, multiple complex emotions interweave in this year

difficult! After two years of rapid development in 2017 and 2018, the number and amount of financing in the artificial intelligence instry in 2019 showed a precipice like decline, capital concentrated in the head enterprises one after another, and the survival of small companies was difficult. Even the head companies have encountered obstacles on the way to listing, and the news of layoffs is constantly shrinking. From the external environment, everyone's life is not easy

awkward! 2019 is also a year of disillusionment. Artificial intelligence was once seen as the next opportunity to create a 10 billion dollar giant after the mobile Internet. But in 2019, before the arrival of general artificial intelligence, it is not as versatile as people think. The public's enthusiasm for artificial intelligence has also decreased a lot. How many people are still concerned about the man-machine battle between Li Shishi and Korean go AI "Han Dou" in December this year<

we should cultivate grain, build high walls and become king slowly. Cheetah global think tank believes that the future of artificial intelligence is not always full of flowers and applause. If artificial intelligence really wants to lead the next decade, practitioners must abandon the flashy valuation, focus on procts, take root in technology and seize the day in the scene

next, cheetah global think tank will comprehensively scan the development of artificial intelligence in 2019 from the aspects of policy, capital, technology, intelligent service robots, AI application scenarios, etc., trying to show you a more comprehensive commercialization of artificial intelligence in 2019.