中国大学MOOC: I have to set numerous alarms for the morning because I sleep like a _______ every night!
中国大学MOOC: I have to set numerous alarms for the morning because I sleep like a _______ every night!
The fire alarms are checked ______ to ensure that they work properly in case of an emergency. A: recently B: almost C: every D: regularly
The fire alarms are checked ______ to ensure that they work properly in case of an emergency. A: recently B: almost C: every D: regularly
People in New York （） A: don’t care about emergencies B: are used to alarms C: are attracted by sounds D: don’t hear loud noises
People in New York （） A: don’t care about emergencies B: are used to alarms C: are attracted by sounds D: don’t hear loud noises
The probability that a particular brand of smoke alarm will function properly and sound an alarm in the presence of smoke is 0.8. You have five such alarms in your home and they operate independently. Which of the following distributions would you use to determine the probability that all of them will function properly in case of a fire A: inomial distribution B: Poisson distribution C: oth of the above D: none of the above
The probability that a particular brand of smoke alarm will function properly and sound an alarm in the presence of smoke is 0.8. You have five such alarms in your home and they operate independently. Which of the following distributions would you use to determine the probability that all of them will function properly in case of a fire A: inomial distribution B: Poisson distribution C: oth of the above D: none of the above
7.The probability that a particular brand of smoke alarm will function properly and sound an alarm in the presence of smoke is 0.You have five such alarms in your home and they operate independently. Which of the following distributions would you use to determine the probability that all of them will function properly in case of a fire A: inomial distribution B: Poisson distribution C: oth of the above D: none of the above
7.The probability that a particular brand of smoke alarm will function properly and sound an alarm in the presence of smoke is 0.You have five such alarms in your home and they operate independently. Which of the following distributions would you use to determine the probability that all of them will function properly in case of a fire A: inomial distribution B: Poisson distribution C: oth of the above D: none of the above
A technician at a small business goes into the server room to perform maintenance on a serverand notices it is very hot and audible alarms are going off. The technician is unsure of how toremedy the situation. Which of the following should the technician do？（） A: Turn off all the equipment in the server closet B: Install a fan in the server closet C: Turn off the power to the server closet D: Follow escalation procedures for emergencies
A technician at a small business goes into the server room to perform maintenance on a serverand notices it is very hot and audible alarms are going off. The technician is unsure of how toremedy the situation. Which of the following should the technician do？（） A: Turn off all the equipment in the server closet B: Install a fan in the server closet C: Turn off the power to the server closet D: Follow escalation procedures for emergencies
The economy of the United States after 1952 was the economy of a well-fed, almost fully employed people. Despite occasional alarms, the country escaped any postwar depression and lived in a state of boom. An economic survey of the year 1955, a typical year of the 1950’s, may be typical as illustrating the rapid economic growth of the decade. The national output was value at 10 percent above that of 1954 (1955 output was estimated at 392 billion dollars). The production of manufacturers was about 40 percent more than it had averaged in the years immediately following World War II. The country’s business spent about 30 billion dollars for new factories and machinery. National income available for spending was almost a third greater than it had been in 1950. Consumers spent about 256 billion dollars; that is about 700 million dollars a day, or about twenty-five million dollars every hour, all round the clock. Sixty-five million people held jobs and only a little more than two million wanted jobs but could not find them. Only agriculture complained that it was not sharing in the boom. To some observers this was an ominous echo of the mid-1920’s. As farmer’s share of their products declined, marketing costs rose. But there were, among the observers of the national economy, a few who were not as confident as the majority. Those few seemed to fear that the boom could not last and would eventually lead to the opposite-depression.
The economy of the United States after 1952 was the economy of a well-fed, almost fully employed people. Despite occasional alarms, the country escaped any postwar depression and lived in a state of boom. An economic survey of the year 1955, a typical year of the 1950’s, may be typical as illustrating the rapid economic growth of the decade. The national output was value at 10 percent above that of 1954 (1955 output was estimated at 392 billion dollars). The production of manufacturers was about 40 percent more than it had averaged in the years immediately following World War II. The country’s business spent about 30 billion dollars for new factories and machinery. National income available for spending was almost a third greater than it had been in 1950. Consumers spent about 256 billion dollars; that is about 700 million dollars a day, or about twenty-five million dollars every hour, all round the clock. Sixty-five million people held jobs and only a little more than two million wanted jobs but could not find them. Only agriculture complained that it was not sharing in the boom. To some observers this was an ominous echo of the mid-1920’s. As farmer’s share of their products declined, marketing costs rose. But there were, among the observers of the national economy, a few who were not as confident as the majority. Those few seemed to fear that the boom could not last and would eventually lead to the opposite-depression.
Modern technology may not haveimproved the world all that much but it certainly has made life noisier. Unruffledmotorcycles, blaring car alarms, and roving boom boxes come first, second, andthird on my list of most obnoxious noise offenders, but everyone could come upwith his own version of aural hell – if he could just find a quiet spot toponder the matter. Yet what technology has done, othertechnology is now starting to undo, using computer power, to zap thoseear-splitting noises into silence. Previously silence-seekers had littlerecourse except to stay inside, close the windows, and plug their ears.Remedies like these are quaintly termed “passive” systems, because they placephysical barriers against the unwanted sound. Now computer technology isproducing a far more effective “active” system, which doesn’t just contain,deflect, or mask the noise, but annihilates it electronically. The system works by countering theoffending noise with “anti-noise”, a somewhat sinister-sounding term that callsto mind antimatter, black holes, and other Popular Science mindbenders but thatactually refers to something quite simple. Just as a wave on a pond isflattened when it merges with a trough that is its exact opposite (or mirrorimage), so can a sound wave be negated by meeting its opposite. This general theory of soundcancellation has been around since the 1930s. In the fifties and sixties itmade for a kind of magic trick among laboratory acousticians playing aroundwith the first clunky mainframe computers. The advent of low-cost high-powermicroprocessors has made active noise-cancellation systems a commercialpossibility, and a handful of small electronics firms in the United States and abroad are bringing the first ones onto the silence market. Silence buffs might be hoping that the noise-canceling apparatus will takethe shape of the 44 Magnum wielded by Dirty Harry, but in fact active soundcontrol is not quite that active. The system might more properly be describedas reactive, in that it responds to sound waves already headed toward humanears. In the configuration that is usual for such systems microphones detectthe noise signal and send it to the system’s microprocessor, which almostinstantly models it and creates its inverse for loudspeakers to fire at theoriginal. Because the two sounds occupy the same range of frequencies andtones, the inverse sounds exactly like the noise it is to eliminate, theanti-noise canceling Beethoven’s Fifth Symphony is heard as Beethoven’s Fifth.The only difference is that every positive pressure produced on the air by theorchestra is matched by a negative pressure produced by the computer, and everynegative pressure is matched by a positive, thereby silencing the sound. The systemis most effective as a kind of muffler, in which microphones, micro-processor,and loudspeaker are all in a unit encasing the device that produces the sound,stifling it at its source. But it can work as a headset, too, negating thesound at the last moment before it disturbs one’s peace of mind. 1. The writer holds that( ). A. modern technology has disturbed thequiet life of the people B. moderntechnology has made people indifferent to noise pollution C. moderntechnology has made the present world quieter than before D.modern technology has failed to solve the problem of noise pollution 2. According to the passage,an active noise-cancellation system ( ). A. contains noise rather than negates it B. eliminates noise rather than muffles it C. deflects noise rather than baffles it D. holds noise back rather than stifles it 3. In paragraph 5 the word “buffs”means ( ). A. settlers B.enthusiasts C. buyers D. manufacturers 4. Which of the followingstatements is NOT true according to the passage? ( ) A.In the past, people sometimes plugged their ears to fight against the offendingnoise. B. An active noise-cancellation systemfollows the principle of a wave being flattened by meeting its exact opposite. C. The first active noise-cancellationsystem was made in the 1930s. D. Active noise-cancellation systems are nowavailable on the market. 5. Activenoise-cancellation systems require ( ). A. microphones B.microprocessors C.loudspeakers D. all of theabove
Modern technology may not haveimproved the world all that much but it certainly has made life noisier. Unruffledmotorcycles, blaring car alarms, and roving boom boxes come first, second, andthird on my list of most obnoxious noise offenders, but everyone could come upwith his own version of aural hell – if he could just find a quiet spot toponder the matter. Yet what technology has done, othertechnology is now starting to undo, using computer power, to zap thoseear-splitting noises into silence. Previously silence-seekers had littlerecourse except to stay inside, close the windows, and plug their ears.Remedies like these are quaintly termed “passive” systems, because they placephysical barriers against the unwanted sound. Now computer technology isproducing a far more effective “active” system, which doesn’t just contain,deflect, or mask the noise, but annihilates it electronically. The system works by countering theoffending noise with “anti-noise”, a somewhat sinister-sounding term that callsto mind antimatter, black holes, and other Popular Science mindbenders but thatactually refers to something quite simple. Just as a wave on a pond isflattened when it merges with a trough that is its exact opposite (or mirrorimage), so can a sound wave be negated by meeting its opposite. This general theory of soundcancellation has been around since the 1930s. In the fifties and sixties itmade for a kind of magic trick among laboratory acousticians playing aroundwith the first clunky mainframe computers. The advent of low-cost high-powermicroprocessors has made active noise-cancellation systems a commercialpossibility, and a handful of small electronics firms in the United States and abroad are bringing the first ones onto the silence market. Silence buffs might be hoping that the noise-canceling apparatus will takethe shape of the 44 Magnum wielded by Dirty Harry, but in fact active soundcontrol is not quite that active. The system might more properly be describedas reactive, in that it responds to sound waves already headed toward humanears. In the configuration that is usual for such systems microphones detectthe noise signal and send it to the system’s microprocessor, which almostinstantly models it and creates its inverse for loudspeakers to fire at theoriginal. Because the two sounds occupy the same range of frequencies andtones, the inverse sounds exactly like the noise it is to eliminate, theanti-noise canceling Beethoven’s Fifth Symphony is heard as Beethoven’s Fifth.The only difference is that every positive pressure produced on the air by theorchestra is matched by a negative pressure produced by the computer, and everynegative pressure is matched by a positive, thereby silencing the sound. The systemis most effective as a kind of muffler, in which microphones, micro-processor,and loudspeaker are all in a unit encasing the device that produces the sound,stifling it at its source. But it can work as a headset, too, negating thesound at the last moment before it disturbs one’s peace of mind. 1. The writer holds that( ). A. modern technology has disturbed thequiet life of the people B. moderntechnology has made people indifferent to noise pollution C. moderntechnology has made the present world quieter than before D.modern technology has failed to solve the problem of noise pollution 2. According to the passage,an active noise-cancellation system ( ). A. contains noise rather than negates it B. eliminates noise rather than muffles it C. deflects noise rather than baffles it D. holds noise back rather than stifles it 3. In paragraph 5 the word “buffs”means ( ). A. settlers B.enthusiasts C. buyers D. manufacturers 4. Which of the followingstatements is NOT true according to the passage? ( ) A.In the past, people sometimes plugged their ears to fight against the offendingnoise. B. An active noise-cancellation systemfollows the principle of a wave being flattened by meeting its exact opposite. C. The first active noise-cancellationsystem was made in the 1930s. D. Active noise-cancellation systems are nowavailable on the market. 5. Activenoise-cancellation systems require ( ). A. microphones B.microprocessors C.loudspeakers D. all of theabove