Message (redirected from messages)

message

(1) An e-mail that contains text and possibly other file attachments. See e-mail.

(2) Any set of transmitted data. Just as a program becomes a job when it runs in the computer, data becomes a message when it is transmitted over a network.

(3) In object technology, communicating between objects, similar to a function call in traditional programming.

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message

1. a formal communiqu?

2. an inspired communication of a prophet or religious leader

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message [′mes·ij]

(communications)

A series of words or symbols, transmitted with the intention of conveying information.

(computer science)

An arbitrary amount of information with beginning and end defined or implied: usually, it originates in one place and is intended to be transmitted to another place.

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message - In object-oriented programming sending a message to an object (to invoke a method) is equivalent to calling a procedure in traditional programming languages, except that the actual code executed may only be selected at run time depending on the class of the object. Thus, in response to the message "drawSelf", the method code invoked would be different if the target object were a circle or a square.

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Message 

in information theory, something conveying information. Information theory is interested only in the quantitative aspect of the information contained in a message.

The concept of a message in information theory has an essentially probabilistic character. Each source of information, or message source, can be specified by listing the possible messages and their corresponding probabilities. Suppose x₁, x₂, . . . . , x_n are the possible messages and p₁, p₂, . . . . , p_n are the corresponding probabilities. The information content of message x_i is then taken as equal to - log₂p_i. An important quantity characterizing a source is the source’s entropy, which is the average information content of the messages from the source. The entropy is thus equal to

It is the magnitude of the entropy that governs the possibility of transmitting and storing the messages produced by the source.

As an example, let us consider a message source that consists of A’ successive measurements of a physical quantity that is uniformly distributed over the interval from 0 to 1. Furthermore, suppose the measurements are accurate to the nearest 0.1. The possible results of the individual measurements can then be regarded as the numbers 0.1, 0.2, . . . , 0.9. The probability of the occurrence of each number is 0.1. The messages in this example are represented by N-term sequences of digits. The probability of each message is (0.1)^N. The information content of each message and the entropy of the source are equal to N log₂10 = 3.32A⁷ binary digits. The message source in this example can be said to be a random sequence of decimal digits of length N. The message sources considered in information theory are of such a form—random sequences of symbols—or, more generally, the form of stochastic processes.

When specific types of messages are studied, such as written texts, telephone signals, telegraph signals, or television signals, an approximate probabilistic model is constructed for the message source. For example, a complex Markov chain can be used for written Russian with sufficient accuracy for the purposes of information theory. Stationary stochastic processes are used as models for continuous messages. The construction of such models is based on extensive statistical data pertaining to the processes under consideration.

IU. V. PROKHOROV