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signal/'sɪgnl/（）

A.标志;表明，用信号通知;表示

B.信号，暗号;暗示

C.种类，分类

D.易受影响的

答案

发布时间：2023-02-18

更多“signal/'sɪgnl/（）”相关的问题

第1题

If you want to be left alone on an elevator, the best thing to do is______.A．to look into

If you want to be left alone on an elevator, the best thing to do is______.

A．to look into another passenger's eyes

B．to avoid eye contact with other passengers

C．to signal you are nor a threat to anyone

D．to keep a distance from other passengers

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第2题

If a person wants to be left alone an elevator，the best thing to do is__________ ．A.to loo

If a person wants to be left alone an elevator，the best thing to do is__________ ．

A.to look into another passenger"s eyes

B.to avoid eye contact with other passengers

C.to signal that he is not a threat to them

D.to keep a certain distance from other passengers

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第3题

根据以下资料，回答{TSE}题。 An old saying has it that half of all advertising budgets are w

asted-the trouble is, no one knows which half .In the internet age, at least in theory ,this fraction can be much reduced .By watching what people search for, click on and say online, companies can aim “behavioural” ads at those most likely to buy. In the past couple of weeks a quarrel has illustrated the value to advertisers of such fine-grained information: Should advertisers assume that people are happy to be tracked and sent behavioural ads？ Or should they have explicit permission？ In December 2010 America's Federal Trade Cornmission (FTC) proposed adding a "do not track "(DNT) option to internet browsers ,so that users could tell adwertisers that they did not want to be followed .Microsoft's Internet Explorer and Apple's Safari both offer DNT ;Google's Chrome is due to do so this year.In February the FTC and Digltal Adwertising Alliance (DAA) agreed that the industry would get cracking on responging to DNT requests. On May 31st Microsoft Set off the row: It said that Internet Explorer 10,the version due to appear windows 8, would have DNT as a default. It is not yet clear how advertisers will respond.Geting a DNT signal does not oblige anyone to stop tracking, although some companies have promised to do so.Unable to tell whether someone really objects to behavioural ads or whether they are sticking with Microsoft’s default, some may ignore a DNT signal and press on anyway. Also unclear is why Microsoft has gone it alone.Atter all, it has an ad business too, which it says will comply with DNT requests, though it is still working out how.If it is trying to upset Google, which relies almost wholly on default will become the norm.DNT does not seem an obviously huge selling point for windows 8-though the firm has compared some of its other products favourably with Google's on that count before.Brendon Lynch, Microsoft's chief privacy officer, bloggde:"we believe consumers should have more control." Could it really be that simple？ {TS}It is suggested in paragraph 1 that “behavioural” ads help advertisers to:

A. ease competition among themselves

B. lower their operational costs

C. avoid complaints from consumers

D. provide better online services

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第4题

Before Moko the dolphin turned up，the beached whales were in clear distress．But when Moko

arrived at Mahia beach on the east coast of New Zealand？S North Island，their mood changed and they followed him to safety． The ability of some animals to communicate is well known. What？s less well documented，however，is the communication between species．Justin Gregg, vice president of the Dolphin Communication Project，said it is possible that a dolphin and a whale could communicate in some way．“But it wouldn？t be instructions like ？Hey，buddy，the open ocean is over here.Follow me, ？"he says． Dolphins use three forms of signaling to other dolphins—whistles，clicking and postures．A whale might have signals in common with a dolphin，just as different species of dolphins are known to share signals which might theoretically allow a form of basic inter species communication．But just as it？s possible that Moko the dolphin and the stranded whales shared a signal，it is also possible that the whales just saw a vaguely similar creature and followed it． There are many reasons why different species communicate，says Vincent Janik，lecturer at the Sea Mammal Research Unit at St Andrew？s University．“The animals exploit the systems of others for their own benefits．Sometimes the benefits are the same for each，therefore they share information．Sometimes they are trying to take advantage of the other．Getting food may not be to the advantage of the one giving up the food” What happened after Moko the dolphin appeared at Mahia beach？

A.The beached whales still felt distressful

B.Moko 1ed the whales back to the sea

C.The whales were still stuck on the beach

D.Moko and the whales swam together ashore

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第5题

Can Burglars Jam Your Wireless Security System？A)Any product that promises to protect your

Can Burglars Jam Your Wireless Security System？

A)Any product that promises to protect your home deserves careful examination. So it isn&39;t surprising that you’ll find plenty of strong opinions about the potential vulnerabilities of popular home-security systems.

B)The most likely type of burglary(入室盗窃)by far is the unsophisticated crime of opportunity, usually involving a broken window or some forced entry. According to the FBI, crimes like these accounted for roughly two-thirds of all household burglaries in the US in 2013. The wide majority of the rest were illegal, unforced entries that resulted from something like a window being left open. The odds of criminal using technical means to bypass a security system are so small that the FBI doesn’t even track those statistics.

C)One of the main theoretical home-security concerns is whether or not a given system is vulnerable to being blocked from working altogether. With wired setups, the fear is that a burglar(入室盗贼)might be able to shut your system down simply by cutting the right cable. With a wireless setup, you stick battery-powered sensors up around your home that keep an eye on windows, doors, motion, and more. If they detect something wrong while the system is armed, they’ll transmit a wireless alert signal to a base station that will then raise the alarm. That approach will eliminate most cord-cutting concerns—but what about their wireless equivalent, jamming？ With the right device tuned to the right frequency, what’s to stop a thief from jamming your setup and blocking that alert signal from ever reaching the base station？

D)Jamming concerns are nothing new, and they’re not unique to security systems. Any device that’s built to receive a wireless signal at a specific frequency can be overwhelmed by a stronger signal coming in on the same frequency. For comparison, let’s say you wanted to “jam” a conversation between two people—all you’d need to do is yell in the listener’s ear.

E)Security devices are required to list the frequencies they broadcast on—that means that a potential thief can find what they need to know with minimal Goog ling. They will, however, need to know what system they’re looking for. If you have a sign in your yard declaring what setup you use, that ’d point them in the right direction, though at that point, we’re talking about a highly targeted, semi-sophisticated attack, and not the sort of forced-entry attack that makes up the majority of burglaries. It’s easier to find and acquire jamming equipment for some frequencies than it is for others.

F)Wireless security providers will often take steps to help combat the threat of jamming attacks. Simpli Safe, winner of our Editors’ Choice distinction, utilizes a special system that’s capable of separating incidental RF interference from targeted jamming attacks. When the system thinks it’s being jammed, it’ll notify you via push alert (推送警报). From there, it’s up to you to sound the alarm manually.

G)Simpli Safe was singled out in one recent article on jamming, complete with a video showing the entire system being effectively bypassed with hand held jamming equipment. After taking appropriate measure to contain the RF interference to our test lab, we tested the attack out for ourselves, and were able to verify that it is possible with the right equipment. However, we also verified that Simpli Safe’s anti-jamming system works. It caught us in the act, sent an alert to my smart phone, and also listed our RF interference on the system’s event log. The team behind the article and video in question make no mention of the system, or whether or not it detected them.

H) We like the unique nature of that software. It means that a thief likely wouldn’t be able to Google how the system works, then figure out a way around it Even if they could, SimpliSafe claims that its system is always evolving, and that it varies slightly from system to system, which means there wouldn’t be a universal magic formula for cracking it Other systems also seem confident on the subject of jamming. The team at Front point addresses the issue in a blog on its site, citing their own jam protection software and claiming that there aren’t any documented cases of a successful jam attack since the company began offering wireless security sensors in the 1980s.

I)Jamming attacks are absolutely possible. As said before, with the right equipment and the right know-how, it’s possible to jam any wireless transmission. But how probable is it that someone will successfully jam their way into your home and steal your stuff？

J) Let’s imagine that you live in a small home with a wireless security setup that offers a functional anti-jamming system. First, a thief is going to need to target your home, specifically. Then, he’s going to need to know the technical details of your system and acquire the specific equipment necessary for jamming your specific setup. Presumably, you keep your doors locked at night and while you&39;re away, so the thief will still need to break in. That means defeating the lock somehow, or breaking a window. He’ll need to be jamming you at this point, as a broken window or opened door would normally release the alarm. So, too, would the motion detectors in your home, so the thief will need to continue jamming once he’s inside and searching for things to steal. However, he’ll need to do so without tripping the anti-jamming system, the details of which he almost certainly does not have access to.

K) At the end of the day, these kinds of systems are primarily designed to protect against the sort of opportunistic smash-and-grab attack that makes up the majority of burglaries. They’re also only a single layer in what should ideally be a many-sided approach to securing your home, one that includes common sense things like sound locks and proper exterior lighting at night. No system is impenetrable, and none can promise to eliminate the worst case completely. Every one of them has vulnerabilities that a knowledgeable thief could theoretically exploit. A good system is one that keeps that worst-case setting as improbable as possible while also offering strong protection in the event of a less-extraordinary attack.

36.It is possible for burglars to make jamming attacks with the necessary equipment and skill.

37.Interfering with a wireless security system is similar to interfering with a conversation.

38.A burglar has to continuously jam the wireless security device to avoid triggering the alarm, both inside and outside the house.

39.Simpli Safe provides devices that are able to distinguish incidental radio interference from targeted jamming attacks.

40.Only a very small proportion of burglaries are committed by technical means.

41.It is difficult to crack SimpliSafe as its system keeps changing.

42.Wireless devices will transmit signals so as to activate the alarm once something wrong is detected.

43.Different measures should be taken to protect one’s home from burglary in addition to the wireless security system.

44.Simpli Safe’s device can send a warning to the house owner’s cellphone.

45.Burglars can easily get a security device’s frequency by Internet search.

请帮忙给出每个问题的正确答案和分析，谢谢！

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第6题

Passage 1 Falls are the number one cause of death ...

Passage 1 Falls are the number one cause of death to old people at home. Most old people can live safely at home if they make a few changes. Falls are common as people are getting older. Up to half of home accidents could be prevented by making some very simple changes. Here are a few suggestions. Mark trouble spots with bright tapes. The first and last steps on stairs are usually high-risk accident are- as. Applying bright tapes and using bright light in these areas would make these spots easier to see. Put grab bars(扶手) in the bathroom. A large number of falls occur in the bathroom. This is unfortunate(不幸的) because it's easy to make the area safe from accidents. Putting grab bars in the bathroom gives people something to hang on to. Invest in a personal alarm. A personal alarm can be started if a person falls or otherwise gets in trouble. With the push of a button, the alarm automatically sends a signal, which gets someone to call and see if the person needs help. 题目： 1. By making some very simple changes at home, old people ______.

A、are free from home accidents

B、can improve their health

C、are likely to live longer

D、can live more safely

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第7题

A new kind of radar has been developed for spaceship travelers. A working laboratory model

of a new system of radar that makes use of a beam of light is said to be ten thousand times more accurate than the best comparable system of radar that used microwaves.

The model has shown that this radar system, known as laser-doppler radar, can measure with absolute precision speeds varying from spaceship orbital injection (进入) velocities (速度) of five miles per second down to virtual stops--speeds of less than one ten thousandth of an inch per second. According to the scientists who are developing this system, such fine measures of velocity are of prime importance in space missions. In a rendezvous (对接) between two spaceships, or in a landing approach by a vehicle onto an orbiting space station, a bump could rip open a ship's skin, or a nudge could knock the station out of its orbit.

The light-beam radar, which operates at a frequency of trillions (百万兆) of cycles per second, could easily detect and measure the movement of a vehicle edging up to a satellite space station. A control system using so precise a signal as this would allow a huge vehicle to dock at a space station as lightly as a feather.

Laser-doppler radar ______. ()

A．measures the movements of a spaceship by means of light beam

B．makes use of microwaves

C．makes use of sound waves

D．Both A and B

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第8题

P£K仪录井的孔隙度计算公式是、φ样=φ标×（S样£¯S标)×（V标£¯V样)。（)

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第9题

下面属于5GNR上行链路reference signal的是() 。

A.Demodulation reference signal for PUSCH 　　