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Numbering
There are many different numbering schemes for assigning nominal numbers to entities. These generally require an agreed set of rules, or a central coordinator. The schemes can be considered to be examples of a primary key In the relational model of databases, a primary key is a designated attribute (column) that can reliably identify and distinguish between each individual record in a table. The database creator can choose an existing unique attribute or combinati ... of a database management system Table (database), table, whose table definitions require a database design. In computability theory, the simplest Numbering (computability theory), numbering scheme is the assignment of natural numbers to a Set (mathematics), set of objects such as function (mathematics), functions, rational numbers, Graph (discrete mathematics), graphs, or words in some formal language. A numbering can be used to transfer the idea of computability and related concepts, which are originally defined on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Numbering Plan
The North American Numbering Plan (NANP) is an integrated telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1, World Numbering Zone 1 and has the telephone country code, country code ''1''. Some North American countries, most notably Telephone numbers in Mexico, Mexico, do not participate in the NANP. The concepts of the NANP were devised originally during the 1940s by the American Telephone and Telegraph Company (AT&T) for the Bell System and the independent telephone companies in North America in Operator Toll Dialing. The first task was to unify the diverse local telephone numbering plans that had been established during the preceding decades, with the goal to speed call completion times and decrease the costs for long-distance calling, by reducing manual labor by switchboard operators. Eventually, it prepared the continent for direct-dialing of long-distance calls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Telephone Numbering Plan
Telephone numbers in Australia are defined and administered by the Australian Communications and Media Authority (ACMA) under delegation by the Department of Infrastructure, Transport, Regional Development, Communications and the Arts, persuant to the Telecommunications Numbering Plan 2025, enacted under subsection 455(1) of the Telecommunications Act 1997. Overview For landline telephony, Australia is geographically divided into four areas, three of which cover more than one state or territory. All local telephone numbers within the four areas have eight digits, consisting (mainly) of a four-digit exchange code and a four-digit local line number. The national significant number consists of a single-digit area code followed by the local eight-digit number, a total of nine digits. Calling within Australia a landline telephone in an area other than that of the caller, the telephone number is preceded by the Australian trunk prefix ''0'' and the area code: 0x xxxx xxxx. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Numbering Plan
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined world-wide, as well as within each of the administrative regions of the public switched telephone network (PSTN), and in private telephone networks. In public numbering systems, geographic location typically plays a role in the sequence of numbers assigned to each telephone subscriber. Many numbering plan administrators subdivide their territory of service into geographic regions designated by a prefix, often called an area code or city code, which is a set of digits forming the most-significant part of the dialing sequence to reach a telephone subscriber. Within such regions designated by area codes, locally unique telephone number are assigned based on lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Country Calling Code
Telephone country codes are telephone number prefixes for reaching subscribers in foreign countries or areas by international direct dialing (IDD). Country codes are defined by the International Telecommunication Union (ITU) in ITU-T standards E.123 and E.164 and constitute the international telephone numbering plan of the public switched telephone network (PSTN) and other networks. Overview This table lists in its first column the initial digits of the country code shared by each country in each row, which is arranged in columns for the last digit (x). When three-digit codes share a common leading pair, the shared prefix is marked by an arrow, () pointing down and left to the three-digit codes. Unassigned codes are denoted by a dash (). Countries are identified by ISO 3166-1 alpha-2 country codes; codes for non-geographic services are denoted by two asterisks (). List by world numbering zones Zone 1: North American Numbering Plan (NANP) North American Numbering Plan me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E Number
E numbers, short for Europe numbers, are codes for substances used as food additives, including those found naturally in many foods, such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly found on food labels, their safety assessment and approval are the responsibility of the European Food Safety Authority (EFSA). The fact that an additive has an E number implies that its use was at one time permitted in products for sale in the European Single Market; some of these additives are no longer allowed today. Having a single unified list for food additives was first agreed upon in 1962 with food colouring. In 1964, the directives for preservatives were added, in 1970 antioxidants were added, in 1974 emulsifiers, stabilisers, thickeners and gelling agents were added as well. Numbering schemes The numbering scheme follows that of the International Numbering System for Food Additives, International Numbering System (INS) as deter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numbering (computability Theory)
There are many different numbering schemes for assigning nominal numbers to entities. These generally require an agreed set of rules, or a central coordinator. The schemes can be considered to be examples of a primary key of a database management system table, whose table definitions require a database design. In computability theory, the simplest numbering scheme is the assignment of natural numbers to a set of objects such as functions, rational numbers, graphs, or words in some formal language. A numbering can be used to transfer the idea of computability and related concepts, which are originally defined on the natural numbers using computable functions, to these different types of objects. A simple extension is to assign cardinal numbers to physical objects according to the choice of some base of reference and of measurement units for counting or measuring these objects within a given precision. In such case, numbering is a kind of classification, i.e. assigning a numeric pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China Telephone Numbering Plan
Telephone numbers in the People's Republic of China are administered according to the Telecommunications Network Numbering Plan of China. The structure of telephone numbers for landlines and mobile service is different. Landline telephone numbers have area codes, whereas mobile numbers do not. In major cities, landline numbers consist of a two-digit area code followed by an eight-digit local number. In other places, landline numbers consist of a three-digit area code followed by a seven- or eight-digit local number. Mobile phone numbers consist of eleven digits. Landline calls within the same area do not require the area code. Calls to other areas require dialing the trunk prefix ''0'' and the area code. The Special administrative regions of China, special administrative regions of Hong Kong and Macau are not part of this numbering plan, and use the calling codes +852, 852 and +853, 853 respectively. Mobile phones In mainland China, mobile phone numbers have eleven digits in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computability Theory
Computability theory, also known as recursion theory, is a branch of mathematical logic, computer science, and the theory of computation that originated in the 1930s with the study of computable functions and Turing degrees. The field has since expanded to include the study of generalized computability and definable set, definability. In these areas, computability theory overlaps with proof theory and effective descriptive set theory. Basic questions addressed by computability theory include: * What does it mean for a function (mathematics), function on the natural numbers to be computable? * How can noncomputable functions be classified into a hierarchy based on their level of noncomputability? Although there is considerable overlap in terms of knowledge and methods, mathematical computability theorists study the theory of relative computability, reducibility notions, and degree structures; those in the computer science field focus on the theory of computational complexity theory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food Additive
Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives, such as vinegar ( pickling), salt ( salting), smoke ( smoking) and sugar ( crystallization), have been used for centuries to preserve food. This allows for longer-lasting foods, such as bacon, sweets, and wines. With the advent of ultra-processed foods in the late 20th century, many additives having both natural and artificial origin were introduced. Food additives also include substances that may be introduced to food indirectly (called "indirect additives") in the manufacturing process through packaging, storage or transport. In Europe and internationally, many additives are designated with E numbers, while in the United States, additives in amounts deemed safe for human consumption are designated as GRAS. Identification To regulate these additives and inform consumers each additive is assigned a unique number called an "E number", whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Telephone Numbering Plan
The French telephone numbering plan is used in Metropolitan France, French overseas departments and some overseas collectivities. Since 1996, Metropolitan France uses a ten-digit closed numbering plan, where the first two digits denote a geographic area, mobile or non-geographic number. * 01 * 02 Northwest France * 03 Northeast France * 04 Southeast France * 05 Southwest France * 06 Mobile phone services * 07 Mobile phone services * 08 Special phone numbers: Freephone () and shared-cost services * 09 Non-geographic number (used by voice over IP services) All geographic numbers are dialed in the ten-digit format, even for local calls. The international access code is the International Telecommunication Union's recommended 00. When calling France from abroad, the leading zero should be omitted: for example, to call a number in Southwest France, one would dial +33 5 xx xx xx xx. Telephone numbers are usually stated as a sequence of five digit-pairs, e.g., 0x xx xx xx xx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zero-based Numbering
Zero-based numbering is a way of numbering in which the initial element of a sequence is assigned the index 0, rather than the index 1 as is typical in everyday non-mathematical or non-programming circumstances. Under zero-based numbering, the initial element is sometimes termed the '' zeroth'' element, rather than the ''first'' element; ''zeroth'' is a coined word for the ordinal number zero. In some cases, an object or value that does not (originally) belong to a given sequence, but which could be naturally placed before its initial element, may be termed the zeroth element. There is no wide agreement regarding the correctness of using zero as an ordinal (nor regarding the use of the term ''zeroth''), as it creates ambiguity for all subsequent elements of the sequence when lacking context. Numbering sequences starting at 0 is quite common in mathematics notation, in particular in combinatorics, though programming languages for mathematics usually index from 1. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone
A telephone, colloquially referred to as a phone, is a telecommunications device that enables two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via Electrical cable, cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from and (, ''voice''), together meaning ''distant voice''. In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. The essential elements of a telephone are a microphone (''transmitter'') to speak into and an earphone (''receiver'') which reproduces the voice a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
