14 专业英语

The purpose of systems design is to specify a(n)( application architecture ) , which defines the technologies to be used to build the proposed information systems. This task is accomplished by analyzing the data models and process models that were initially created during ( requirements analysis ). The ( physical data flow diagram ) is used to establish physical processes and data stores across a network. To complete this activitly, the analyst may involve a number of system designers and ( system users ), which may be involved in this activity to help address business data, process, and location issues. The key inputs to this task are the facts, recommendations, and opinions that are solicited from various sources and the approved ( system proposal ) from the decision analysis phase.

The objective of ( architecture design ) is to determine what parts of theapplication software will be assigned to what hardware. The major software components of the system being developed have to be identified and then allocated to the various hardware components on which the system will operate. All sofware systems can be divided into four basic functions. The first is ( data storage ). Most information systems require data to be stored and retrieved, whether a small file, such as a memo produced by a word processor, or a large database, such as one that stores an organization’s accounting records. The second function is the ( data access login ), the processing required to access data, which often means database queries in Structured Query Language. The third function is the ( application logic ), which is the logic documented in the DFDs use cases, and functional requirements. The fourth function is the presentation logic, the display of information to the user and the acceptance of the user’s commands. The three primary hardware components of a system are ( clients, server and network ).

Software architecture reconstruction is an interpretive, interactive, and iterative process including many activities. ( Information extration ) involves analyzing a system’s existing design and implementation artifacts to construct a model of it. The result is used in the following activities to construct a view of the system, The database construction activity converts the ( elements and relations ) contained in the view into a standard format for storage in a database. The ( view fusion ) activity involves defining and manipulating the information stored in database to reconcile, augment, and establish connections between the elements. Reconstruction consists of two primary activities （ visualization and interation ）and ( pattern definition and recognition ). The former provides a mechanism for the user to manipulate architectural elements, and the latter provides facilities for architecture reconstruction.

The software architecture is a set of software conponents, subsystems, relationships, interactions, the properties of each of these elements, and the set of guiding principles that together constitute the fundamental properties and constraints of a software system or set of systems. ( Architectural pattern ) defines a general set of element types and their interactons. The examples include Pipes and Filters,Model-View-Controller, and Reflection. A ( Model ) in software architecture is a resentation used to understand or document one or more aspects of a problem or solution. Architecture is usually used in conjunction with many adjunct terms. The ( business architecture ) defines the key strateges, organization, goals and related processes of the enterprise. At the enterprise level, the ( application architecture ) may be more of a st of guidelines on how the various software archiectures should be constructed consistently across the enterprise. The （ reference architecture ）, which describes the high-level set of elements involved in application from a particular domain along with their interactions, is often used to focus on subsystem definition rather than application process level definition.