(51) 在OSI參考模型中,同等層相互交換信息的實體構成了____。
A) 相鄰實體 B) 對等實體 C) 傳輸實體 D) 通信實體
(52) 在OSI參考模型中,兩個(N)層實體之間交換的數據單元稱之為(N)協議數據單元,記做(N)PDU。(N)PDU是由兩部分組成:(N)PCI與 ____。
A) (N+1)IDU B) (N+1)SDU C) (N)SDU D) (N)IDU
(53) 一個數據源產生8bit的ASCII字符(含1bit校驗位),通過一條64Kbps的線路進行數據傳輸。指出在以下數據傳輸方式中,哪一種方式的有效數據傳輸速率可以達到最高? ____。(2分)
A) 采用面向字符型傳輸協議,每個數據幀包括24B的控制字段與128B的信息字段
B) 除信息字段長度為256B外,其它條件同A)
C) 采用面向比特型傳輸協議,每個數據幀包括12B的控制字段與64B的信息字段
D) 除信息字段長度為128B外,其它條件同C)
(54) 在面向比特型數據鏈路層協議HDLC中,幀格式中的哪個域既可以用于流量控制,又可以實現對發送幀的捎帶確認?____。（2分）
A) 無編號幀的M域 B) 信息幀的N(S)域
C) 監控幀的S域 D) 信息幀的N(R)、N(S)域
(55) IEEE802.5標準規定令牌環網采用 ____。
A) 多令牌協議
B) 單令牌協議
C) 隨機訪問協議
D) HDLC協議
(56) 在局域網中,以下哪種傳輸介質既可以用于物理層10BASE-T協議,又可以適用于100BASE-T協議? ____。
A) 同軸電纜 B) 3類非屏蔽雙絞線
C) 5類非屏蔽雙絞線 D) 光纖電纜
(57) 如果兩個局域網LAN A與LAN B互連,它們的傳輸層協議不同,而其它層協議均相同, LAN A與LAN B的互連設備應該選擇____。
A) repeater B) bridge C) router D) gateway
(58) CCITT推薦的用于多個X.25網絡互連的協議為____。
A) X.400 B) X.75 C) X.121 D) X.21
(59) 城市地區網(MAN)主要使用的技術是交換多兆位數據服務SMDS、分布隊列雙總線DQDB和____。
A) FDDI B) CSMA/CD C) Token Bus D) Token Ring
(60) 在計算機集成制造系統(CIMS)中,存在著辦 公自動化(OA)與生產過程控制(MC)兩種環境,它們對網絡通信的要求也不相同。在CIMS環境中,根據MAP/TOP協議選擇局域網協議標準時，應采用以下哪種方案? ____。(2分)
A) 全部采用802.3協議標準
B) OA采用802.3協議標準,MC采用802.4協議標準
C) OA采用802.3協議標準,MC采用802.5協議標準
D) 全部采用HDLC協議標準
(61) An instrucion that uses indirect addressing must contain an address of memory where____．
A) data is stored B) another address is stored
C) a page fault is addressed D) a pepeline stall will be executed
(62) Let R be a binary relation on a set S such that for each x,y,z∈S, if xRy and xRz then y =z. Which of the following must be true? ____．(2分)
A) R is anti-symmetric B) R is transitive
C) R is an equivalence relation D) R is a function
(63) If p and q are Boolean variables, which of the following formulas is (are) tautological?____．
Ⅰ. (┐p→q)↔ (p∨q)
Ⅱ. ((p→q))∧(q→r))→(p→r))
A) none B) Ⅰ only C) Ⅱ only D) Ⅰ and Ⅱ
(64) Which of the following statements is (are) true? ____．
Ⅰ. The number of cyclic subgroups of the additive group of integers is infinite.
Ⅱ. The number of cyclic subgroups of the additive group of real numbers is infinite.
A)&nb sp;Neither B) Ⅰ only C) Ⅱ only D) Ⅰ and Ⅱ
Questions 65- 66 refer to the space requirements of different methods of storing graphs. The choices for these questions are combinations of the following statements.
Ⅰ. The space required depends on the number of vertices.
Ⅱ. The space required depends on the number of edges.
(65) When the adjacency matrix method is used to store a graph, which of the statements is (are) true? ____．
A) None B) Ⅰ only C) Ⅱ only D) Ⅰ and Ⅱ
(66) When the adjacency list method is used to store a graph, which of the statements is (are) true?____．
A) None B) Ⅰ only C) Ⅱ only D) Ⅰ and Ⅱ
Questions 67-68 are based on the following information,
A hash table with hash function
h1(k)=k mod 13
is shown below.
0 1 2 3 4 5 6 7 8 9 10 11 12
35 33 48 25
Collision is resolved using the hash function h2(k)=(k mod 11)+1.
(67) How many key comparisons occur in searching for key 35 in the given hash table?____． (2分)
A) 0 B) 1 C) 2 D) 3
(68)& If a new key 67 is inserted into the given hash table, what will be its address?____． (2分)
A) 3 B) 4 C) 5 D) 6
(69) Suppose the contents of the DOS IF1.BAT file on the hard disk is as follows.
@ECHO OFF
MEM>FILE1
SORTFILE2
DEL FILE1
@DATE
@TIME
IF EXIST %1 ECHO % IF FOUND
If all of the commands are successfully executed after IF1 FILE1 is
typed, then the screen displays?____．
A) None B) Date and time C) FILE1 IS FOUND D) FILE2 IS FOUND
(70) If the files in the current directory are
aac, abc, acb,acc, aca, ao, al, a2, ab, ac, aa,
and the command ls a?[bc] is executed, how many files will be listed?____． (2分)
A) 3 B) 4 C) 5 D) 6
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