单项选择题 ATM网络采用(11)多路技术传送信元，典型的数据速率为155.5Mbit/s，这样每秒大约可以传送(12)万个信元。采用短的、固定长度的信元，为使用硬件进行高速数据交换创造了条件。ATM是为B-ISDN定义的传输和交换方式，可以适应各种不同特性的电信业务，CBR(Constant Bit Rate)模拟(13)业务，适用这种业务的ATM适配层是(14)，用于ATM局域网仿真的ATM适配层是(15)。

单项选择题 analysis emphasizes the drawing of pictorial system models to document and validate both existing and/or proposed systems. Ultimately, the system models become the(32)for designing and constructing an improved system. (33)is such a technique. The emphasis in this technique is process-centered. Systems analysts draw a series of process models called(34). (35)is another such technique that integrates data and process concerns into constructs called objects.

单项选择题 In recent years, one of the more popular topics for panel discussions at computer conferences and trade(61)has been the 'RISC versus CISC' debate.RISC processors feature a small number of instructions that each executes in(62)machine cycle. CISC processors use complex instructions that can take several cycles to execute.The RISC versus CISC debate won't be decided by panel discussion; it will be won in the marketplace. And the deciding factor may have little to do with(63)of instructions and registers and more to do with parallelism.Since their conception, RISC processors have been evolving toward micro parallelism, incorporating parallel-processing features(64)the processor, RISC processors feature pipelining, whereby many instructions can be decoded while one instruction executes. RISC processors, however, are moving toward pipelines for each unit of the processor.CISC processors also employ pipelining. They have many integer instructions that execute in one cycle, but the varying execution times of CISC instructions(65)the effectiveness of parallelism.

单项选择题 The Rational Unified Process(RUP)is a software engineering process, which captures many of best practices in modem software development. The notions of(36)and scenarios have been proven to be an excellent way to capture function requirements. RUP can be described in two dimensions - time and content. In the time dimension, the software lifecycle is broken into cycles. Each cycle is divided into four consecutive(37)which is concluded with a well-defined(38)and can be further broken down into(39)-a complete development loop resulting in a release of an executable product, a subset of the final product under development, which grows incrementally to become the final system. The content structure refers to the disciplines, which group(40)logically by nature.

单项选择题 The growth of switching has(135)a new generation of network management tools that help(136)cope with the challenges,(137)them to correlate device alarms in order to(138)pinpoint root causes, or to monitor service levels without depending on IP subnet schemes. These new tools have become essential to coping with the primary(139)effect of any treatment that significantly increases network flexibility: added complexity.