一个软件产品开发完成投入使用后，常常由于各种原因需要对它做适当的变更。在软件的使用过程中，软件原来的(48)可能不再适应用户的要求，需要进行变更；软件的工作环境也可能发生变化：最常见的是配合软件工作的(49)有变动；还有一种情况是在软件使用过程中发现错误，需要进行修正。通常把软件交付使用后做的变更称为(50)。软件投入使用后的另一项工作是(51)，针对这类软件实施的软件工程活动，主要是对其重新实现，使其具有更好的(52)，包括软件重构、重写文档等。(51)和新的软件开发工作的主要差别在于 (53)。

(79)

(78)

(77)

(75)

(76)

(73)

(74)

(72)

(71)

Due to a constantly(66) environment, a poor understanding of the user's needs and preferences, as well as a(67) of willingness to modify.(68) organizational structures and decision models, the full economic potential of Web Information Systems (WIS) has not been realized by now. The data object types of the(69) meta. model, the Extended World Wide Web Design Technique (eW3DT), provide hypertext designers(70) a conceptual, user-centric framework and graphical notation for the construction of both,(71) and customized models, during the software development(72) of commercial WIS. A reference model as a normative concept represents an abstraction of a(73) company, its functional units, or its Web Information System and is intended to streamline the design and implementation of complex applications at(74) costs. As precondition for pursuing a partial globalization strategy,eW3DT(75) between technical and content-specific responsibilities for designing, implementing, and maintaining WIS.