毕业设计外文原文及译文
题目： 北京市丰台区佃起村信息化网站的设计与开发 专业： 信息管理与信息系统 指导教师： 学院： 管理学院 学号： 班级： 姓名：
一、外文原文
The basic functions of an information system are to enable the user to get quick access to recorded information, to enter data of various forms into the system by both manual and automatic means to perform speedy data analysis with the aid of the system, to display the desired information for visual inspection or permanent record, and to edit and modify the displayed information as needed. Thus, an information system will be composed of functionally the following principal elements: data entry, data display, data file， data analysis, and data access.
The data entry sub-system serves as the input device for reading data in the form of characters, waveforms, graphs, maps, and pictures into the information system. The data entry may be done manually by teletype, light pen or graph pens and it can be performed automatically by OCR device or other sophisticated pattern recognition equipment. Some data entry device can be used for graphical and alphanumeric input into the computer system simultaneously as the information is recorded onto a document. Sophisticated data entry sub-system is indeed a kind of information system itself.
The data display sub-system serves as the output device for exhibiting and recording printed materials or graphics. Among the commonly used output devices are line printers, data plotters, cathode-ray tube, and interactive graphics which are capable of performing query, transfer, deleting and editing. The main categories of data plotters are drum plotter, flatbed plotter, CRT plotter， raster scanner, electrostatic printer plotter， micro-scanner plotter， and Laser image processing scanner. For the drum plotter, the material on which plotting is made moves along one axis as the writing instrument is moved along the other axis to generate the two-dimensional movement. The plotting material of a flatbed plotter remains stationary, while the marking instrument moves in both x and y directions; and the fundamental recording material in the CRT system ends up being film. The raster scanner has to create a binary image of the entire plot before the plotting can be done, which
requires disk, storage. The Laser image processing scanner developed by CBS Laboratories is a high resolution scanner, computer interface and plotter. The trend is to design intelligent graphics terminals which combine facilities with the ability to perform a considerable amount of local processing, to relieve the main computer of large amounts of I/O for low-level interaction, and to provide the user with immediate response to simple data analysis and symbol manipulation requests. An intelligent graphics terminal is considered as an important element of the information system.
The data file system, also known as the database system, is the major element of an information system. Data consists of numbers, names, codes and symbols. Each of these items is often referred to as a data element. A database may be defined as an integrated collection of accessible interrelated data. A database comprises simple items, which are called attributes or fields, and compound items which are files, records and links. A file is a compound item made up of an arbitrary number of records, each record having the same logical structure. A link or pointer is a reference to an item that relates to another item which may be physically remote. In an information system, there are two different types of data elements: physical and logical. Physical data elements are the storage cells, addressable by either hardware or software, and usually connoted by such words as bit, byte, block, and segment. On the other hand, logical elements refer to the information carrying items and their relationship to one another. Such terms as files, arrays, records and fields refer to logical data elements. The major requirements for a database are: 1) to permit extremely rapid access to its contents, (2) to provide interactive query and editing capability, (3) to facilitate data analysis and manipulations, and (4) to place no software limitations on database size by obtaining space from secondary storage as it is needed.
In early computer applications in engineering and science, data storage presented few structural problems to the programmer since data were usually organized in a manner similar to the address structure of the physical storage media of the computer. Applications to non-numerical data processing, such as pattern recognition, artificial intelligences and information retrieval, have revealed that interpretive systems were often slow and cumbersome, and sophisticated users needed new computer storage organizations which were more compatible with highly structured data. Early non-numerical computer applications pointed out that a database not only has information in its contents, but also contains as much information (sometimes even more information) in its structure.
An information system is a very complex and sophisticated communication system which emphasizes not only the physical aspects but also the semantic aspects of
information communication and data analysis. Conventional communication systems involve a very simple retrieval scheme, i.e., channel selection. Each channel is precisely specified by a code number, and the numbers of available channels are small. However, an information system involves a very complex and sophisticated retrieval scheme for data access. The media of communication are the files. Unlike a telephone system, the major complexity lies not in the switching of lines among various subscribers, but in the provision of file structures as central media of communication through which relatively complicated information processing takes place.
The generated information is transmitted via documents, which may include monographs, books, reports, letters, memos, charts, graphics, and pictures. Data elements are stored in an information system in an organized manner to preserve interrelationships and to provide access from one data element to another. This organization of data is often referred to as a data structure. In information systems all data structures can be built up from four basic schemes: sequential structure, random structure, list structure, and hierarchical structure. The data access techniques are dependent upon the type of data structures which will be discussed in the following sections.
二、译文
一个信息系统的基本功能是让用户能够快速访问存取记录的信息，通过手动和自动方式输入到系统中的各种形式的数据，在该系统的帮助下进行迅速的数据分析，以显示所需的信息进行目视检查或永久记录，并根据需要编辑和修改显示的信息。因此，一个信息系统是由以下重要的功能元素组成：数据输入，数据显示，数据文件，数据分析和数据访问。
数据输入子系统作为输入设备读取数据的字符形式、波形、图表、地图和照片到信息系统中。数据输入可能会通过电传，光笔或图形笔手工完成，它可以自动通过OCR设备或其他复杂的模式识别设备执行。某些数据输入装置可用于图形和字母数字输入到计算机系统中，同时，作为信息记录到一个文件中。复杂的数据输入子系统本身的确是一种信息系统。
数据输出子系统作为输出设备，用于展示和记录印刷材料或图形。其中常用的输出设备是行式打印机，绘图机，阴极射线管和交互图形，能够进行查询，传输，删除和编辑。数据绘图机的主要类别是鼓绘图仪，平板绘图仪，CRT绘图仪，光栅扫描仪，静电打印机绘图仪，微型扫描仪绘图仪，激光图像处理扫描器。相对于鼓绘图仪，在其上绘图的材料是作为书写工具沿一个轴移动，沿另一个轴的移动生成二维运动。平板绘图仪的绘图材料保持静止，而标记工具在x和y方向移动，在CRT系统的基本记录材料中作为膜结束。光栅扫描仪在绘图完成前创建一个整个绘图的二进制图