Basics: Infringement and Fair Use The Yet copyright laws also provide that the rights of copyright owners are subject to the doctrine of " - the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes (usually certain types of educational copying are allowed) - the nature of the copyrighted work (mostly originals made for commercial reasons are less protected than their purely artistic counterparts) - the amount and substantiality of the portion used in relation to the copyrighted work as a whole - the effect of the use upon the potential market for or value of the copyrighted work (as a general rule copying may be permitted if it is unlikely to cause economic harm to the original author) Examples of activities that may be excused as fair use include: providing a quotation in a book review; distributing copies of a section of an article in class for educational purposes; and imitating a work for the purpose of parody or social commentary. |
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Optical communication system by Aeneas Tacitus, 4th century B.C. Aeneas Tacitus, a Greek military scientist and cryptographer, invented an optical communication system that combines water and beacon telegraphy. Torches indicated the beginnings and the ends of message transmissions while water jars were used to transmit the messages. These jars had a plugged standard-size hole drilled on the bottom side and were filled with water. As those who sent and those who received the message unplugged the jars simultaneously, the water drained out. Because the transmitted messages corresponded to water levels, the sender indicated by torch signal that the appropriate water level has been reached. It is a disadvantage that the possible messages are restricted to a given code, but as this system was mainly used for military purposes, this was offset by the advantage that it was almost impossible for outsiders to understand these messages unless they possessed the codebook. With communication separated from transportation, the distant became near. Tacitus' telegraph system was very fast and not excelled until For further information see Joanne Chang & Anna Soellner, Decoding Device, |
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