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Ralph Hartley | A Wisdom Archive on Ralph Hartley |  | Ralph Hartley A selection of articles related to Ralph Hartley |  |
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Ralph Hartley
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| ARTICLES RELATED TO Ralph Hartley | | |  |  |  | Ralph Hartley: Encyclopedia II - Information theory - Applications
Information theory - Coding Theory.
Coding theory is the most important and direct application of information theory. It can be subdivided into data compression theory and error correction theory. Using a statistical description for data, information theory quantifies the number of bits needed to describe the data. There are two formulations for the compression problem -- in lossless data compression the data must be reconstructed exactly, whereas lossy data compression examines how many bits are needed to recons ...
See also:Information theory, Information theory - Mathematical preliminaries, Information theory - Basic Concepts for Discrete Channels, Information theory - Self-information, Information theory - Entropy, Information theory - Joint Entropy, Information theory - Conditional Entropy Equivocation, Information theory - Mutual Information Transinformation, Information theory - Continuous Channels, Information theory - Channel Capacity, Information theory - Source Theory, Information theory - Rate, Information theory - Fundamental Theorem, Information theory - Statement Noisy-Channel Coding Theorem, Information theory - Channel capacity of particular model channels, Information theory - Related Concepts, Information theory - Measure Theory, Information theory - Kolmogorov Complexity, Information theory - Applications, Information theory - Coding Theory, Information theory - Cryptography Cryptanalysis, Information theory - Relation with thermodynamic entropy, Information theory - Quantum Information Theory, Information theory - Detection and Estimation Theory, Information theory - Gambling, Information theory - Intelligence, Information theory - Music, Information theory - History Read more here: » Information theory: Encyclopedia II - Information theory - Applications |
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|  |  |  | Ralph Hartley: Encyclopedia II - 1970 - Births
1970 - January.
January 6 - Gabrielle Reece, American volleyball player and model
January 13 - Keith Coogan, American actor
January 13 - Marco Pantani, Italian cyclist (d. 2004)
January 15 - Shane McMahon, American Wrestler
January 17 - Jeremy Roenick, American hockey player
January 17 - Gennady Tartakovsky Russian animator
January 20 - Skeet Ulrich, American actor
January 22 - Alex Ross, American comic artist
January 29 - Heather Graha ...
See also:1970, 1970 - Events, 1970 - January, 1970 - February, 1970 - March, 1970 - April, 1970 - May, 1970 - June, 1970 - July, 1970 - August, 1970 - September, 1970 - October, 1970 - November, 1970 - December, 1970 - Unknown date, 1970 - Births, 1970 - January, 1970 - February, 1970 - March, 1970 - April, 1970 - May, 1970 - June, 1970 - July, 1970 - August, 1970 - September, 1970 - October, 1970 - November, 1970 - December, 1970 - Unknown date, 1970 - Deaths, 1970 - January, 1970 - February, 1970 - March, 1970 - April, 1970 - May, 1970 - June, 1970 - July, 1970 - August, 1970 - September, 1970 - October, 1970 - November, 1970 - December, 1970 - Unknown date, 1970 - Nobel Prizes, 1970 - Fields Medalists Read more here: » 1970: Encyclopedia II - 1970 - Births |
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|  |  |  | Ralph Hartley: Encyclopedia II - Information theory - Mathematical preliminariesInformation theory is based on and intimately connected with probability theory.
In information theory, logarithms are used extensively. The base of the logarithms used here is deliberately left unspecified, following standard practice in information theory. As in many other applications of logarithms, it really does not matter much what base is used as long as one is consistent. In the case of information theory, the choice of logarithmic base merely determines the unit that is used to measure information. Common choices of logarithm ...
See also:Information theory, Information theory - Mathematical preliminaries, Information theory - Basic Concepts for Discrete Channels, Information theory - Self-information, Information theory - Entropy, Information theory - Joint Entropy, Information theory - Conditional Entropy Equivocation, Information theory - Mutual Information Transinformation, Information theory - Continuous Channels, Information theory - Channel Capacity, Information theory - Source Theory, Information theory - Rate, Information theory - Fundamental Theorem, Information theory - Statement Noisy-Channel Coding Theorem, Information theory - Channel capacity of particular model channels, Information theory - Related Concepts, Information theory - Measure Theory, Information theory - Kolmogorov Complexity, Information theory - Applications, Information theory - Coding Theory, Information theory - Cryptography Cryptanalysis, Information theory - Relation with thermodynamic entropy, Information theory - Quantum Information Theory, Information theory - Detection and Estimation Theory, Information theory - Gambling, Information theory - Intelligence, Information theory - Music, Information theory - History Read more here: » Information theory: Encyclopedia II - Information theory - Mathematical preliminaries |
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|  |  |  | Ralph Hartley: Encyclopedia II - 1970 - Deaths
1970 - January.
January 4 - Jean-Etienne Valluy, French general (b. 1899)
January 5 - Max Born, German physicist, Nobel Prize laureate (b. 1882)
January 10 - Pavel Belyayev, cosmonaut (b. 1925)
January 18 - David O. McKay, president of The Church of Jesus Christ of Latter-day Saints (b. 1873)
January 25 - Jane Bathori, French mezzo-soprano (b. 1877)
January 27 - Rita Angus, New Zealand painter (b. 1908)
January 29 - Basil Liddell Hart, British military h ...
See also:1970, 1970 - Events, 1970 - January, 1970 - February, 1970 - March, 1970 - April, 1970 - May, 1970 - June, 1970 - July, 1970 - August, 1970 - September, 1970 - October, 1970 - November, 1970 - December, 1970 - Unknown date, 1970 - Births, 1970 - January, 1970 - February, 1970 - March, 1970 - April, 1970 - May, 1970 - June, 1970 - July, 1970 - August, 1970 - September, 1970 - October, 1970 - November, 1970 - December, 1970 - Unknown date, 1970 - Deaths, 1970 - January, 1970 - February, 1970 - March, 1970 - April, 1970 - May, 1970 - June, 1970 - July, 1970 - August, 1970 - September, 1970 - October, 1970 - November, 1970 - December, 1970 - Unknown date, 1970 - Nobel Prizes, 1970 - Fields Medalists Read more here: » 1970: Encyclopedia II - 1970 - Deaths |
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|  |  |  | Ralph Hartley: Encyclopedia II - Bell Labs - BasisThe work done by Bell Labs was broadly divided into three categories: research, systems engineering, and development.
Research created the theoretical underpinnings for telecommunications. It covered subjects such as mathematics, physics, material sciences, behavioral sciences, and computer programming theory.
Systems engineering concerned itself with conceiving the highly complex systems that make up the telecommunication networks.
Development, by far the largest of Bell Labs' activities designed the specific systems -- both hardware and software -- needed to build the Bell Sy ...
See also:Bell Labs, Bell Labs - History, Bell Labs - Basis, Bell Labs - Calculators built by Bell Labs Read more here: » Bell Labs: Encyclopedia II - Bell Labs - Basis |
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|  |  |  | Ralph Hartley: Encyclopedia II - Information theory - Continuous ChannelsShannon information is appropriate for measuring uncertainty over a discrete space. Its basic measures have been extended by analogy to continuous spaces. The continuous entropy, joint entropy, and conditional entropy are not quite as meaningful as the corresponding measures in the discrete case. Here they can take on negative as well as positive values, and they are not invariant under linear transformation. The mutual information has the distinction of being the only one of Shannon's basic measures of information that remains fundamentally ...
See also:Information theory, Information theory - Mathematical preliminaries, Information theory - Basic Concepts for Discrete Channels, Information theory - Self-information, Information theory - Entropy, Information theory - Joint Entropy, Information theory - Conditional Entropy Equivocation, Information theory - Mutual Information Transinformation, Information theory - Continuous Channels, Information theory - Channel Capacity, Information theory - Source Theory, Information theory - Rate, Information theory - Fundamental Theorem, Information theory - Statement Noisy-Channel Coding Theorem, Information theory - Channel capacity of particular model channels, Information theory - Related Concepts, Information theory - Measure Theory, Information theory - Kolmogorov Complexity, Information theory - Applications, Information theory - Coding Theory, Information theory - Cryptography Cryptanalysis, Information theory - Relation with thermodynamic entropy, Information theory - Quantum Information Theory, Information theory - Detection and Estimation Theory, Information theory - Gambling, Information theory - Intelligence, Information theory - Music, Information theory - History Read more here: » Information theory: Encyclopedia II - Information theory - Continuous Channels |
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|  |  |  | Ralph Hartley: Encyclopedia II - Information theory - Channel CapacityLet us return for the time being to our consideration of the communications process over a discrete channel. At this time it will be helpful to have a simple model of the process:
+-------+
| Noise |
+-------+
|
V
+-----------+ Y +-------+ X +--------+
|Transmitter|-------->|Channel|-------->|Receiver ...
See also:Information theory, Information theory - Mathematical preliminaries, Information theory - Basic Concepts for Discrete Channels, Information theory - Self-information, Information theory - Entropy, Information theory - Joint Entropy, Information theory - Conditional Entropy Equivocation, Information theory - Mutual Information Transinformation, Information theory - Continuous Channels, Information theory - Channel Capacity, Information theory - Source Theory, Information theory - Rate, Information theory - Fundamental Theorem, Information theory - Statement Noisy-Channel Coding Theorem, Information theory - Channel capacity of particular model channels, Information theory - Related Concepts, Information theory - Measure Theory, Information theory - Kolmogorov Complexity, Information theory - Applications, Information theory - Coding Theory, Information theory - Cryptography Cryptanalysis, Information theory - Relation with thermodynamic entropy, Information theory - Quantum Information Theory, Information theory - Detection and Estimation Theory, Information theory - Gambling, Information theory - Intelligence, Information theory - Music, Information theory - History Read more here: » Information theory: Encyclopedia II - Information theory - Channel Capacity |
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|  |  |  | Ralph Hartley: Encyclopedia II - Information theory - Fundamental Theorem
Information theory - Statement Noisy-Channel Coding Theorem.
1. For every discrete memoryless channel, the channel capacity
has the following property. For any ε > 0 and R < C, for large enough N, there exists a code of length N and rate ≥ R and a decoding algorithm, such that the maximal probability of block error is ≤ ε.
2. If a probability of bit error pb is acceptable, ra ...
See also:Information theory, Information theory - Mathematical preliminaries, Information theory - Basic Concepts for Discrete Channels, Information theory - Self-information, Information theory - Entropy, Information theory - Joint Entropy, Information theory - Conditional Entropy Equivocation, Information theory - Mutual Information Transinformation, Information theory - Continuous Channels, Information theory - Channel Capacity, Information theory - Source Theory, Information theory - Rate, Information theory - Fundamental Theorem, Information theory - Statement Noisy-Channel Coding Theorem, Information theory - Channel capacity of particular model channels, Information theory - Related Concepts, Information theory - Measure Theory, Information theory - Kolmogorov Complexity, Information theory - Applications, Information theory - Coding Theory, Information theory - Cryptography Cryptanalysis, Information theory - Relation with thermodynamic entropy, Information theory - Quantum Information Theory, Information theory - Detection and Estimation Theory, Information theory - Gambling, Information theory - Intelligence, Information theory - Music, Information theory - History Read more here: » Information theory: Encyclopedia II - Information theory - Fundamental Theorem |
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|  |  |  | Ralph Hartley: Encyclopedia II - Information theory - Source TheoryAny process that generates successive messages can be considered a source of information. Sources can be classified in order of increasing generality as memoryless, ergodic, stationary, and stochastic, (with each class strictly containing the previous one). The term "memoryless" as used here has a slightly different meaning than it normally does in probability theory. Here a memoryless source is defined as one that generates successive messages independently of one another and with a fixed probability distribution. However, the position of t ...
See also:Information theory, Information theory - Mathematical preliminaries, Information theory - Basic Concepts for Discrete Channels, Information theory - Self-information, Information theory - Entropy, Information theory - Joint Entropy, Information theory - Conditional Entropy Equivocation, Information theory - Mutual Information Transinformation, Information theory - Continuous Channels, Information theory - Channel Capacity, Information theory - Source Theory, Information theory - Rate, Information theory - Fundamental Theorem, Information theory - Statement Noisy-Channel Coding Theorem, Information theory - Channel capacity of particular model channels, Information theory - Related Concepts, Information theory - Measure Theory, Information theory - Kolmogorov Complexity, Information theory - Applications, Information theory - Coding Theory, Information theory - Cryptography Cryptanalysis, Information theory - Relation with thermodynamic entropy, Information theory - Quantum Information Theory, Information theory - Detection and Estimation Theory, Information theory - Gambling, Information theory - Intelligence, Information theory - Music, Information theory - History Read more here: » Information theory: Encyclopedia II - Information theory - Source Theory |
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|  |  |  | Ralph Hartley: Encyclopedia II - Information theory - Related Concepts
Information theory - Measure Theory.
Here is an interesting and illuminating connection between information theory and measure theory:
If to arbitrary discrete random variables X and Y we associate the existence of sets and , somehow representing the information borne by X and Y, respectively, such that:
and are disjoint whenever X and Y are independent, and
whenever X and Y are such that either one is completel ...
See also:Information theory, Information theory - Mathematical preliminaries, Information theory - Basic Concepts for Discrete Channels, Information theory - Self-information, Information theory - Entropy, Information theory - Joint Entropy, Information theory - Conditional Entropy Equivocation, Information theory - Mutual Information Transinformation, Information theory - Continuous Channels, Information theory - Channel Capacity, Information theory - Source Theory, Information theory - Rate, Information theory - Fundamental Theorem, Information theory - Statement Noisy-Channel Coding Theorem, Information theory - Channel capacity of particular model channels, Information theory - Related Concepts, Information theory - Measure Theory, Information theory - Kolmogorov Complexity, Information theory - Applications, Information theory - Coding Theory, Information theory - Cryptography Cryptanalysis, Information theory - Relation with thermodynamic entropy, Information theory - Quantum Information Theory, Information theory - Detection and Estimation Theory, Information theory - Gambling, Information theory - Intelligence, Information theory - Music, Information theory - History Read more here: » Information theory: Encyclopedia II - Information theory - Related Concepts |
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