若海明码的监督关系为：S0=a0+a3+a4+a6；S1=a1+a3+a5+a6：S2=a2+a4+a5+a6。若需发送的信息为：1101，则信道中传输的码字为(12)，该海明码的编码效率为(13)。

(159)

(158)

(157)

For each blank, choose the best answer from the four choices and write down on the answer sheet.

(71)is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed-length bit string.

(72)is a protocol that most USENET machines now use it to allow news articles to propagate from one machine to another over a reliable connection.

(73)is an approach preferred by cable TV providers. In this solution the fiber terminates at an optoelectrical converter and the final segment is a shared coaxial cable.

(74)is a device used to connect two separate network that use different communication protocol.

(75)is a digital-to-digital polar encoding method in which the signal level is always either positive or negative.

(156)

(153)

(154)

(152)

帧中继网的虚电路建立在()

(151)