外文翻译高级数据库应用.docx

1、外文翻译高级数据库应用 毕业设计（论文）外文翻译题 目 高级数据库应用 专 业 信息与计算科学 班 级 学 生 指导教师 Advanced Database ApplicationsThe 1990s have seen significant changes in the computer industry. In database systems, we have seen the widespread acceptance of RDBMSs for traditional business applications, such as order processing, inventor

2、y control, banking, and airline reservations. However, existing RDBMSs have proven inadequate for applications whose needs are quite different from those of traditional business database applications. These applications include: computer-aided design (CAD); computer-aided manufacturing (CAM); comput

3、er-aided software engineering (CASE); office information systems (OIS) and multimedia systems; digital publishing; eographic information systems (GIS); interactive and dynamic Web sites.Computer-aided design (CAD)A CAD database stores data relating to mechanical and electrical design covering, for e

4、xample, buildings, aircraft, and integrated circuit chips. Designs of this type have some common characteristics: Design data is characterized by a large number of types, each with a small number of instances. Conventional databases are typically the opposite. For example, the DreamHome database con

5、sists of only a dozen or so relations, although relations such as PropertyForRent, Client, and Viewing may contain thousands of tuples. Designs may be very large, perhaps consisting of millions of parts, often with many interdependent subsystem designs. The design is not static but evolves through t

6、ime. When a design change occurs, its implications must be propagated through all design representations. The dynamic nature of design may mean that some actions cannot be foreseen at the beginning. Updates are fat-reaching because of topological or functional relationships, tolerances, and so on. O

7、ne change is likely to affect a large number of design objects. Often, many design alternatives are being considered for each component, and the correct version for each part must be maintained. This involves some form of version control and configuration management. There may be hundreds of staff i

8、nvolved with the design, and they may work in parallel on multiple versions of a large design. Even so, the end-product must be consistent and coordinated. This is sometimes referred to as cooperative engineering.Computer-aided manufacturing （CAM）A CAM database stores similar data to a CAD system, i

9、n addition to addition to data relating to discrete production (such as cars on an assembly line) and continuous production (such as chemical synthesis). For example, in chemical manufacturing there will be applications that monitor information about the state of the system, such as reactor Bessel t

10、emperatures, flow rates, and yields. There will also be applications that control various physical processes, such as opening valves, applying more heat to reactor vessels, and increasing the flow of cooling systems. These applications are often organized in a hierarchy, with a top-level application

11、 monitoring the entire factory and lower=level applications monitoring individual manufacturing processes. These applications must respond in real time and be capable of adjusting processes to maintain optimum performance within tight tolerances. The applications use a combination of standard algori

12、thms and custom rules to respond to different conditions. Operators may modify these rules occasionally to optimize performance based on complex historical data that the system has to maintain. In this example, the system has to maintain large volumes of data that is hierarchical in nature and maint

13、ain complex relationships between the data. It must also be able to rapidly navigate the data to review and respond to changes.Computer-aided software engineering (CASE)A CASE database stores data relating to stages of the software development lifecycle: planning, requirements collection and analysi

14、s, design, implementation, testing, maintenance, and documentation. As with CAD, designs may be extremely large, and cooperative engineering is the norm. For example, software configuration management tools allow concurrent sharing of project design, code, and documentation. They also track the depe

15、ndencies between these components and assist with change management. Project management tools facilitate the coordination of various project management activities, such as the scheduling of potentially highly complex interdependent tasks, cost estimation, and progress monitoring.Network management s

16、ystemsNetwork management systems coordinate the delivery of communication services across a computer network. These systems perform such tasks as network path management, problem management, and network planning. As with the chemical manufacturing example we discussed earlier, these systems also han

17、dle complex data and require real-time performance and continuous operation. For examples, a telephone call might involve a chain of network switching devices that route a message from sender to receiver, such as: NodeLinkNodeLinkNodeLinkNodeWhere each Node represents a port on a network device and

18、each Link represents a slice of bandwidth reserved for that connection. However, a node may participate in several different connections and any database that is created has to manage a complex graph of relationships. To route connections, diagnose problems, and balance loadings, the network managem

19、ent systems have to be capable of moving through this complex graph in real time.Office information systems (OIS) and multimedia systemsAn OIS database stores data relating to the computer control of information in a business, including electronic mail, documents, invoices, and so on. To provide bet

20、ter support for this area, we need to handle a wider range of data types other than names, addresses, dates, and money. Modern systems now handle free-form text, photographs, diagrams, and audio and video sequences. For example, a multimedia document may handle text, photographs, spreadsheets, and v

21、oice commentary. The documents may have a specific structure imposed on them, perhaps described using a mark-up language such as SGML (Standardized Generalized Markup Language), HTML (HyperText Markup Language), or XML (eXtended Markup Language), as we discuss in Chapter 29.Documents may be shared a

22、mong many users using systems such as electronic mail and bulletin-boards based on Internet technology. Again ,such applications need to store data that has a much richer structure than tuples consisting of numbers and text strings. There is also an increasing need to capture handwritten notes using

23、 electronic devices. Although many notes can be transcribed into ASC text using handwriting analysis techniques, most such data cannot. In addition to words, handwritten data can include sketches, diagrams and so on.In the DreamHome case study, we may find the following requirements for handling mul

24、timedia. Image data A client may query an image data base of properties for rent. Some queries may simply use a textual description to identify images of desirable properties. In other cases it may be useful for the client to query using graphical images of features that may be found in desirable pr

25、operties (such as bay windows, internal cornicing, or roof gardens). Video data A client may query a video database of properties for rent. Some queries may simply use a textual description to identify the video images of desirable properties. In other cases it may be useful for the client to query

26、using video features of the desired properties (such as views of the sea or surrounding hills). Audio data A client may query an audio database that describes the features of properties for rent. Some queries may simply use a textual description to identify the desired property. In other cases it ma

27、y be useful for the client to use audio features of the desired properties (such as the noise level from nearby traffic). Handwritten data A member of staff may create notes while carrying out inspections of properties for rent. At a later data, he or she may wish to query such data to find all note

28、s made about a flat in Novar Drive with dry rot.Digital publishingThe publishing industry is likely to undergo profound changes in business practices over the next decade. It is becoming possible to store books, journals, papers, and articles electronically and deliver them over high-speed networks

29、to consumers. As with office information systems, digital publishing is being extended to handle multimedia documents consisting of text, audio, image, and video data and animation. In some cases, the amount of information available to be put online is enormous, in the order of petabytes (1015 bytes

30、), which would make them the largest databases that a DBMA has ever had to manage.Geographic information systems (GIS)A GIS database stores various types of spatial and temporal information, such as that used in land management and underwater exploration. Much of the data in these systems is derived

31、 from survey and satellite photographs, and tends to be very large. Searches may involve identifying features based, for example, on shape, color, or texture, using advanced pattern-recognition techniques.For example, EOS (Earth Observing System) is a collection of satellites launched by NASA in the

32、 1990s to gather information that will support sci8entists concerned with long-term trends regarding the earths atmosphere, oceans, and land. It is anticipated that these satellites will return over one-third of a petabyte of information per year. This data will be integrated with other data sources and will be stored in EOSDIS (EOS Data and Information System). EOSDIS will supply the information needs of both scientists and non-scientists. For example, schoolchildren will be able to access EOSDIS to see a simulation of world weather patterns. The immense size