| 单词 | information content natural unit(NAT) |
| 释义 | information content natural unit(NAT)In information theory, a unit of logarithmic measure of information expressed by the Naperian logarithm, e.g., the decision content of a character set of eight characters equals log[e]8=2.079=3 log[e] 2 natural units of information content. Let a, b, c be the characters of a character set consisting of three elements, and let the probabilities of their occurrence within any message, from a given message source, be specified as follows: \\ \\ p(a)=1/2 \\ p(b)=P(c)=1/4 \\ (a) The decision content of this character set is: \\ H[0]=log[2] 3=1.580 Shannons \\ H[0]=log[10] 3=0.477 Hartley \\ H[0]=log[e] 3=1.098 natural units \\ (b) The information content of these characters are: \\ I(a)=log[2] 2=1.000 Shannons \\ I(a)=log[10] 2=0.301 Hartley \\ I(a)=log[e] 2=0.693 natural units \\ \\ I(b)=I(c)=log[2] 4=2.000 Shannons \\ I(b)=I(c)=log[10] 4=0.602 Hartley \\ I(b)=I(c)=log[e] 4=1.386 natural units \\ (c) If the occurrences of the three characters within any message are mutually \\ independent, then the entropy of the message source is: \\ H=1/2log2+1/4log4+1/4log4 \\ H=1.500 Shannons \\ H=1.5×0.301=0.452 Hartley \\ H=1.5×0.693=1.040 natural units \\ (d) The redundancy of the message source is: \\ H[0]H=0.080 Shannons \\ H[0]H=0.025 Hartley \\ H[0]H=0.058 natural units; 在信息论中,一种用自然对数表示的信息量的对数量度单位。例如,八个字符的字符集的 判定量等于log[e]8=2.079=3log[e]2信息量自然单位。假定a，b，c是由三个元素组成的字 符集中的字符,在任何来自某一给定信息源的信息中它们出现的概率指定为: \\ \\ p(a)=1/2 \\ p(b)=P(c)=1/4 \\ (1) 这个字符集的判定量是: \\ H[0]=log[2]3=1.580 香农 \\ H[0]=log[10] 3=0.477 哈特利 \\ H[0]=log[e]3=1.098 自然单位 \\ (2) 这些字符的信息量是: \\ I(a)=log[2]2=1.000 香农 \\ I(a)=log[10] 2=0.301 哈特利 \\ I(a)=log[e]2=0.693 自然单位 \\ \\ I(b)=I(c)=log[2] 4=2.000 香农 \\ I(b)=I(c)=log[10] 4=0.602 哈特利 \\ I(b)=I(c)=log[e] 4=1.386 自然单位 \\ (3) 如果这三个字符在任何信息中的出现是相互独立的,则这个信息源的熵是: \\ H=1/2log2+1/4log4+1/4log4 \\ H=1.500 香农 \\ H=1.5×0.301=0.452 哈特利 \\ H=1.5×0.693=1.040 自然单位 \\ (4) 信息源的冗余为: \\ H[0]H=0.080 香农 \\ H[0]H=0.025 哈特利 \\ H[0]H=0.058 自然单位 |
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