Definition and classification of natural gemstones

As far as I know, a gem is defined as a natural, beautiful, durable, rare mineral single crystal (which can be processed into jewelry).

There is another saying about the classification of natural gemstones, which can be roughly divided into four categories.

1. High-grade gem: refers to the traditional precious gem with high value. Diamond, ruby, sapphire, emerald, golden green jade (cat's eye, metamorphic rock)

2. Middle and low-grade gems: gems with low relative value. Crystal, garnet, olivine, etc.

3. Rare gems: gems with low output and insufficient circulation in the market.

4. Decorative stones.

Hope to adopt

The characteristic carrier of information is dependent, wireless and inexhaustible, and the effectiveness of value-added applications is universal.

The definition and attribute of intelligence is the specific knowledge and information needed to solve specific problems in scientific research and production by using certain media (carrier) and passing it to specific users across space and time. 1, knowledge (The essence of intelligence is knowledge. Without a certain amount of knowledge, it can't be intelligence. Knowledge is the most important attribute of intelligence. 2. Transitivity (Knowledge cannot constitute intelligence if it is not communicated and used by people. 3. Utility (Information serves users and users need information. Utility is an important symbol to measure information work. )

The types of information sources are divided into five types according to the forms of information sources: personal information sources, organizational information sources, physical information sources, literature information sources and electronic information sources.

Information source defines information source: the source of information obtained by individuals to meet their information needs.

Document definition knowledge is recorded on a certain carrier (paper, disk, CD-ROM, etc.) in a certain way (words, images, sounds). ) is called a document. Literature is the external expression of knowledge. Four elements of literature: information content (ideology and knowledge concept expressed in literature. It is the connotation and soul of literature, which directly reflects the expression of literary spiritual products and has knowledge and information value), information symbols (symbol system is a symbol to reveal the content of literary information, a means to express knowledge and information, and a medium to record and spread the content of literary information), recording methods (the information content represented by the document symbol system is attached to certain document carrier materials through specific manual recording means and methods) and carrier materials (all the material materials for recording information symbols).

Information source includes three elements: information producer, information and information technology.

Subject language: narrative words, meta-words, headline words and keywords.

According to the depth of information sources, the types of documents can be divided into zero-order documents, primary documents, secondary documents and tertiary documents.

1, zero-time literature: the most primitive literature that has not been published or spread into society.

2. Primary literature: papers, reports and other published or published literature based on the author's own achievements are used to becoming original literature.

3. Secondary literature: Secondary literature is a systematic, orderly, easy-to-find, concentrated and simplified product of identifying, screening, analyzing, summarizing, processing and reorganizing a large number of scattered and unorganized primary literature in a certain range or discipline according to a specific purpose.

4. The third document: according to the clues provided by the second document, a large number of the contents of the first document were screened, analyzed, synthesized and concentrated before being published again.

Literature information types: (1), books (2) periodicals (3) dissertations (4) scientific reports (5) patent documents (6) standard documents (7) product samples (8) conference documents (9) government publications.

The narrow concept of information resources holds that information resources refer to a collection of useful information that has been processed, sorted out and accumulated in a large number in human social and economic activities.

Information resources in a broad sense refer to the collection of information and activity elements accumulated in human social information and activities, such as information materials and producer information technology.

Generally speaking, information resources are a collection of various elements of information activities (information producers, information technology, equipment, facilities, funds, etc.). ) accumulated in the activities of human information society with information as the core.

Information resource elements, information producer information, information technology

The difference between information sources and information resources Information sources are not equal to information resources, they are closely related and different. Information source is the source of information resources, which precedes information resources and can be continuously transformed into information resources; However, information sources are not equal to information resources. Information source is everything that contains information, and information resource is a collection of available information. Information resources can be high-quality and high-purity information sources, but not all information resources.

Characteristics of information culture: digital globalization, virtual interaction, openness, autonomy, self-discipline, freedom and equality.

The connotation of medical information literacy mainly includes information consciousness, information knowledge, information courage and information morality.

1, information consciousness: refers to the reflection of information in the human brain, that is, people's conscious psychological reflection of all kinds of information, reflecting people's understanding, attitude, value orientation and certain needs of information in the process of information activities.

2. Information knowledge: refers to theories, knowledge and methods related to information.

3. Information courage: refers to the ability to effectively use information technology and information resources to obtain information, process information and create and exchange new information.

4. Information ethics: refers to certain ethical norms that should be observed in the process of information acquisition, use, creation and dissemination.

Types of information retrieval, literature retrieval, fact retrieval and data retrieval

Types of information retrieval 1, literature retrieval (it is the most important and basic retrieval to find the literature with specific related content, such as the literature of a certain theme or a certain work, and then obtain relevant information from the found literature. 2. Fact retrieval (the retrieval object is a specific fact, and the retrieval result is a specific answer about something, so fact retrieval is a deterministic retrieval. 3. Data retrieval (the retrieval object is specific data, and the retrieval results are all kinds of tested and evaluated data, which can be directly used for comparative analysis or quantitative analysis. This is a deterministic search. Information retrieval system consists of computer hardware, computer software and database.

Database: the information source of information retrieval system is a set of interrelated data stored on disk, tape or CD in a certain way.

The composition of the database: documents, records and fields.

Database types: bibliographic database, fact database, numerical database, full-text database and image database.

There are many retrieval languages in the world, which are divided into different types according to their classification methods. There are retrieval languages that express the external characteristics of documents and retrieval languages that express the content characteristics of documents.

Information retrieval languages: classification languages and subject languages. (Title words, meta words, keywords)

Classified language: it uses the principle of logical classification to condense documents according to the theme and specialty of document content, and reveals the differences and connections of various documents from the perspective of knowledge classification, so as to gather documents with the same nature, connect documents with similar properties and separate documents with different properties.

Information retrieval methods: classification, subject method, keyword method, author method, title method, number method and other methods.

Classification method Classification method is a method to retrieve documents according to the subject category required by the document content, and search by classification number or category. Classification can be used to understand the relationship between subject concepts such as subordination, juxtaposition and correlation, and it is suitable for retrospective retrieval and generalized concept retrieval (large-scale concepts), and can meet the requirements of clan retrieval (literature collection by subject). The recall rate is high but the accuracy is low.

Information retrieval technology: Boolean logic retrieval, cut-off retrieval, location retrieval and limited domain retrieval.

Information retrieval strategy: (1), analyze the retrieval theme, and define the objectives and requirements; (2) Selection of retrieval system and database; (3) Select the retrieval method and determine the retrieval mark; (4) Write retrieval expressions and adjust retrieval strategies; (5) Obtain original vouchers.

The following principles should be mastered when choosing a retrieval system: matching majors, large number of documents reported, large amount of information, fast reporting speed, short time difference and many retrieval ways.

Recall rate: refers to the ratio between the detected related documents and the related documents actually stored in all document databases.

Recall rate = number of related documents detected \ total number of related documents in the document library * 100%.

Accuracy rate: refers to the proportion of relevant documents needed in the detected documents.

Accuracy = number of related documents \ number of all documents detected * 100%

Measures to improve the retrieval effect: (1), measures to improve the recall rate: a, try to combine keywords and keywords for retrieval; B, keyword retrieval should be expanded, and all sub-keyword retrieval should be used; C, classified retrieval, need to expand retrieval and full retrieval; D, deleting unimportant concept group surfaces for reduction and operation; E, using synonyms for OR operation retrieval; F, using cut-off word retrieval, etc. (2) Measures to improve the accuracy: a, use standardized keywords and sub-topic phrases for retrieval, and use less or no free words; B, carrying out weighted search by limiting key word fields of main concepts; C, adding conceptual planes AND connecting them with AND operators; D, excluding irrelevant concepts with the NOT operator; E, limited search fields, such as literature type, language, author, journal name, etc. ; F, use the relaxed position operator, etc.

Search Engine: Is it the Internet and

Extended data

The reason for this is the following：

1, the program has a major bug, the program can't start, or quit halfway.

2. Bypassing Apple's payment channel, we used the exchange code to exchange gold coins in the previous game.

3. If there are physical rewards in the game, it must be made clear that the rewards are the responsibility of the company and have nothing to do with Apple.

4. Use the Apple logo. (If the design of the application is too similar to Apple's Logo style, it will be rejected. )

5. The network function cannot be accessed normally.

6. You can't click the icon. Icons that cannot be clicked should be grayed out or hidden directly.

7. There is no default page, and the startup screen is black, which has a certain rejection probability.

8. An application is online, but if you want to send a deluxe version or something, opening another application will also be rejected.

OS (Apple Mobile Operating System) Locking iOS is a mobile operating system developed by Apple. Apple announced this system for the first time at Macworld conference on June 9, 2007. Originally designed for iPhone, it was later applied to iPodtouch, iPad, AppleTV and other products.

IOS, like Apple's MacOSX, is a commercial operating system similar to Unix. Originally this system was called iPhoneOS. Because iPad, iPhone and iPod Touch all use iPhoneOS, it was announced at the 20 10WWDC conference that it was renamed as iOS(iOS is a registered trademark of Cisco's network equipment operating system in the United States, and Apple's renaming has been authorized by Cisco).