LECTURE NOTES BY DR.B.RAMA DEVI

Click Here to Download Resolution Weak slot filler Structure Knowledge Representation Unification . Forward and backward Chaining Conceptual Dependency

 A Case Study: Design a Document Editor ¾     This chapter presents a case study in the design of a "What-You-See-Is-What-You-Get" (or "WYSIWYG") document editor called Lexi. ¾     We'll see how design patterns capture solutions to design problems in Lexi. ¾     A WYSIWYG representation of the document occupies the large rectangular area in the center. ¾     The document can mix text and graphics freely in a variety of formatting styles. ¾     Surrounding the document are the usual pull-down menus and scroll bars, and a collection of page icons for jumping to a particular page in the document.    Design Problems: Seven problems in Lexis's design: Document Structure: The choice of internal representation for the document affects nearly every aspect of Lexis's design.    All editing, formatting, displaying, and textual analysis will require traversing the representation.   The way we organize those impacts design information.

Unit-1 Introduction 1.1What is a Design Pattern?      Designing reusable object-oriented software is  harder. ·       Must find relevant objects, factor them into classes at the right granularity, define class interfaces and inheritance hierarchies, and establish key relationships among them. ·       Design should be specific to the problem at hand but also general enough to address future problems and requirements. ·       Avoid redesign, or at least minimize it. ·       Expert designers reuse solutions that have worked for them in the past. ·       When they find a good solution, they use it again and again; consequently, you'll find recurring patterns of classes and communicating objects in many object-oriented systems. ·       These patterns solve specific design problems and make object-oriented designs more flexible, elegant, and ultimately reusable. ·       A designer who is familiar with such patterns can apply them immed