It is nearly 35 years since I gave the 7th Sir Frederick Bartlett lecture at Oxford University. This was published as a paper entitled "Orienting of attention in the quarterly journal". The topic was then pr...
详细信息
It is nearly 35 years since I gave the 7th Sir Frederick Bartlett lecture at Oxford University. This was published as a paper entitled "Orienting of attention in the quarterly journal". The topic was then primarily in psychology, but now equally often in neuroscience. This paper summarizes the background of the reaction time methods used in the original paper and findings that emerged later on the sensory consequences of orienting, mainly in the visual system. It then discusses the brain network that is the source of the sensory amplification and other brain networks that are involved in attention. Next, it reviews studies of the development of attentional networks in early life. Finally, it indicates how the new tools available to explore the human brain can lead to further progress.
作者：
CHEN, CHResearch Department
Sperry Univac Abstract Authors References Cited By Keywords Metrics Similar Download Citation Email Print Request Permissions
Arithmetic codes use a structured redundancy technique for binary number representation such that errors in an arithmetic operation of a digital computer can be detected or corrected. This correspondence studies the c...
详细信息
Arithmetic codes use a structured redundancy technique for binary number representation such that errors in an arithmetic operation of a digital computer can be detected or corrected. This correspondence studies the code structures by treating the set of redundant coded binary representations as a finite Abelian group. An algebraic model of arithmetic codes is developed, which shows that an arithmetic code is a pair of cyclic group isomorphisms. Two theorems are derived which describe the necessary and sufficient conditions for the existence of an arithmetic code. It is also shown that the group of redundant coded binary numbers is isomorphic to a cyclic group, or the direct sum of two cyclic groups. For a given code generator A and the information cardinality m, the two theorems may be applied to find all existing arithmetic codes up to an isomorphism. The algebraic structures of all codes published to date are covered by the mathematical model described in this correspondence.
暂无评论