问题 单项选择题

为提高数据传输的可靠性,可采用“冗余校验”的方法;海明码是常用的方法之一。在此方法中,若要求能检测出所有的双位错,并能校正单位错,则合法码字集中的码距至少为 (127) 。若原始数据的字长为5位,则采用海明码时其校验位至少为 (128) 位。

对图1-22的图(a)所示系统,仅当部件1,部件2和部件3,全部正常工作时,系统才能正常工作。图中数字为各部件的可靠性,整个系统的可靠性近似为 (129) 。如果将部件2和部件3改成由两个器件构成,如图(b)所示,只要器件a和b中有一个正常就能使部件2正常工作,只要器件c和d中有一个正常就能使部件3正常工作。图中数字是各器件的可靠性,则部件2的可靠性是 (130) ,整个系统的可靠性近似为 (131)

130()

A.0.64

B.0.88

C.0.96

D.0.99

答案

参考答案:C

完形填空
A camp built by students and volunteers spreads over Southern Methodist University(SMU). The affordable  21  are designed to be used by the poor as well as survivors of war and natural disasters.
“By the time 2020, there’s going to be about 1.7 billion people living in slums(贫民窟) so we would like to  22  change,” says Stephanie Hunt, co-founder of the Hunt Institute for Engineering and Humanities at SMU. The institute, which  23  build the village on SMU’s campus, was established to solve problem of the poor in the United States and around the world through engineering, and the free  24 .
The goal is not just to  25  lives, but to change the victims’ lives. The Institute hopes some entrepreneurs(企业家) might program and  26  some money with these ideas. One of the structures in the SMU village was built with bricks made  27  from recycled plastic bags.
They’re  28  together with heavy wires. Harvey Lacey, father of two college-aged sons, including one here at SUM, heard about this project and  29  his invention. It’s a heavy-duty, hand-crank compactor(手动压缩机)that anybody can use to form the big bricks he calls Ubuntu Blox.
“The advantages are that these  30  weigh less than two pounds. They’re very, very  31  These things can go for many generations of housing, ”says Lacey, who is  32  the design. Anybody can follow his online plans to  33  the compactor that turns plastic bags into bricks.
On this warm day, it’s  34  inside the Ubuntu Blox hut, thanks  35  to the thick plastic insulation(绝缘). Kenyan  36  Ronald Omyonga, visiting the global village before returning to his native Africa, says his country is full of these recyclable bags. With Lacey’s design, he says that litter could be transformed into  37  housing. He dreams of other  38  too.
“Look at the Harvey Lacey hut, as a means of creating  39  ,”says Omyonga.“Leaning the environment, and turning  40  into something that can form houses, not just for the poor.”
小题1:
A.sheltersB.clubsC.partiesD.rooms
小题2:
A.affectB.adaptC.effectD.adopt
小题3:
A.discoveredB.helpedC.studiedD.explored
小题4:
A.entryB.competitionC.tradeD.market
小题5:
A.saveB.surviveC.defendD.cure
小题6:
A.shareB.donateC.earnD.cost
小题7:
A.brieflyB.relevantlyC.mostlyD.efficiently
小题8:
A.heldB.stressedC.knockedD.packed
小题9:
A.deliveredB.contributedC.devotedD.sacrificed
小题10:
A.pilesB.massesC.loavesD.blocks
小题11:
A.fragileB.thickC.hardD.bitter
小题12:
A.giving outB.giving offC.giving upD.giving away
小题13:
A.buildB.inventC.improveD.possess
小题14:
A.hotB.coldC.wetD.cool
小题15:
A.nearlyB.exactlyC.partlyD.fairly
小题16:
A.doctorB.athleteC.photographerD.architect
小题17:
A.safeB.dangerousC.beautifulD.large
小题18:
A.advantagesB.chancesC.benefitsD.profits
小题19:
A.thingsB.jobsC.wondersD.conditions
小题20:
A.wasteB.resourcesC.ideasD.technology
问答题 简答题