单选题A mobile earth station in the maritime mobile-satellite service,which is located on board ship,is called（）.A an LESB an SESC a ship stationD a Land Mobile Station

RFC3270describesDifferentiatedServices（Diff-Serv）overMulti-ProtocolLabelSwitching（MPLS）networks.WhichmodelaltersDifferentiatedServices（Diff-Serv）codepointssetindifferentDifferentiatedServices（Diff-Serv）domain？（）

A.Uniformmodel

B.PipeModel

C.ShortPipe

D.NoneoftheabovewillalterDifferentiatedServices（Diff-Serv）codepointssetindifferent DifferentiatedServices（Diff-Serv）domain

Believe it or not，the day when you can go to the moon is coming soon．You can go into space (11) space shuttle．It (12) about three days for the shuttle to go from the earth to the moon． The shuttle flies a long way to a space station． You can stay there for a short rest and then it will (13) you to the moon．

Now you can jump out of the shuttle． But you mustn't take (14) your spacesuit，because it is very hot in the daytime and very cold at night on the moon． The moon is much smaller than the earth． Things are (15) 0n the moon than they are on the earth． You can jump high every time you take a step． You will find that it is never tiring to walk on the moon． You don't need to take an umbrella or a raincoat with you，(16) there is no rain on the moon You can hear (17) because there is no air on the moon． And there are no animals or(18) living things there．

The moon moves more slowly than the earth，so one day on the moon is as long as two weeks on the earth and one night is just as long as two weeks on the earth． What could you do in (19 )long days and nights and in a silent world?' Now scientists are trying to make the (20) 0f the moon． But our earth is really a far better place to live，as long as we take good care of it，

( )11．

A．on

B．in

C．by

D．with

【An overall cellular network contains a number of different elements from the base transceiver station (BTS) itself with its antenna back through a base station controller (BSC), and a mobile switching centre (MSC) to the location registers (HLR and VLR) and the link to the public switched telephone network (PSTN). Of the units within the cellular network, the BTS provides the direct communication with the mobile phones. There may be a small number of base stations then linked to a base station controller. This unit acts as a small centre to route calls to the required base station, and it also makes some decisions about which of the base station is best suited to a particular call. The links between the BTS and the BSC may use either land lines of even microwave links. Often the BTS antenna towers also support a small microwave dish antenna used for the link to the BSC. The BSC is often co-located with a BTS. The BSC interfaces with the mobile switching centre. This makes more widespread choices about the routing of calls and interfaces to the land line based PSTN as well as the HLR and VLR.】 From the paragraph above, in a cellular network, the （98） can provide direct communication with a mobile phone, the （99） acts as a small centre to route calls to the required base station, and it also makes some decisions about which of the base station is best suited to a particular call.（100） can be used to link the BSC with related BTS。

A. BSC B. BTS C. MSC D. VLR A. BSC B. BTS C. MSC D. HLR A. Land lines B. Microwave links C. Microwave dish antenna D. Land lines or microwave links

There is a ______ when one or more vessels are towing or pushing another vessel or vessels，provided that they are all involved in commercial activities and not in a salvage operation．

A.private safety

B.private maritime adventure

C.common safety

D.common maritime adventure

The Safety of Life at Sea Convention was developed by the ______.

A.IMDG conference

B.American Bureau of Shipping

C.International Maritime Organization

D.American Institute of Maritime Shipping

A．错误

B．正确

Maritime Administration personnel may be allowed in the pilothouse upon the responsibility of the ______.

A.Chief Officer

B.Navigator

C.most senior person present from the Maritime Administration

D.officer in charge of the watch

CDMA for cellular system can be described as follows. As with FDMA, each cell is allocated a frequency （71） , when is split into two parts, half for reverse (mobile unit to base station) and half for （72） (base station to mobile unit). For full-duplex （73） , a mobile unit both reverse and forward channels. Transmission is in the form. of direct-sequence spread （74） , which used a chipping code to increase the data rate of the transmission, resulting is an increased signal bandwidth. Multiple access is provided by assigning （75） chipping codes to multiple users, so that the receiver can recover the transmission of an individual unit from multiple transmissions.

A.ware

B.signal

C.bandwidth

D.domain

The international body responsible for drafting the convention prohibiting marine pollution (MARPOL) is the ______.

A.Maritime Advisory Council

B.International Maritime Organization

C.International Association of Shipping

D.Association of Seafaring Nations