(1)Computers and Speech Recognition
______computers would seem much friendlier if it were possible to verbally ask them for______information for command them to carry out______task, and if they could respond by talking in______natural, conversational English． However,______prospects for automatic recognition of fluent, continuous speech in______near future are not encouraging, in part because of______complexity of______task and in part because of inadequate research support．
______fundamental question in automatic speech recognition by computers is how much information is contained in______acoustic wave patterns that make up______words and sentences used in communicating by voice． In other words, can______machine decipher____a__voice command and act on it simply by decoding______wave pattern, or does it need to ‘know’certain additional information? In all cases,______answer seems to be that______extra knowledge must be programmed into______computer．
______speech recognition by______computer comprises two operations．______first is decomposition of acoustic wave patterns into______basic sound or elements of speech, called phonemes．______existing speech recognition machines do this job with no more than 65 percent accuracy, in part because______wave patterns corresponding to neighboring phonemes tend to overlap．______second operation is to arrange______phonemes into words and______words into sentences, taking into account that______substantial fraction of______phonemes may be misidentified, and it is here that______need for linguistic and contextual knowledge arises．
(Adapted from Arthur L． Robinson, Communicating with Computers by Voice, Science, Vol． 203,No． 23,February 23,1979,P．734)
(2)How a Bus Work(www.xing528.com)
The function of______bus is to transfer information in______form of electric signals between different parts of______electronic system．______generic term for system components connected by______bus is devices．______group of devices is connected to______bus segment．
Only one device,______bus master, is allowed to control______bus and initiate data transfers at any one time． Several masters may be present on______bus, so contention between them must be resolved using______arbitration rules．
______bus master either oversees______transfer of______data between______devices or, more often, exchanges information with one or more slaves．______bus master selects slaves by placing address information on______bus; each slave compares this information with its own address． If the addresses match,______master and slave establish______connection and______slave becomes______responder． Addresses that identify more than one slave are called______broadcast addresses． Particular device may act as both master and slave, but not at______same time．
Once______slaves are connected,______bus master exchanges data with them over____bus．______master breaks______connection with its responders after all______data have been transferred． This sequence of actions—making______connection, transferring data, breaking______connection—is called______transaction． The master may either relinquish bus mastership after______transaction or continue with other transactions．
(Adapted from W． Kenneth Dawson and Robert W． Dobinson． What a bus is and How it works: A Primer． IEEE Spectrum,1986-10,P:52-53)
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