nó một lần thứ hai. Có mà ngữ nghĩa từ một lần nữa. Đây có phải là ngữ nghĩa giống như chúng ta đã thấy trong chương trước, như Chương 13, "RDF"? A: Không, thuật ngữ ngữ nghĩa là một trong những xuất hiện trong một số bối cảnh XML. | 618 Chapter 16 Classroom Q A Q Hold it a second. There s that word semantics again. Is this the same semantics we ve seen in previous chapters like Chapter 13 RDF A No the term semantics is one that appears in several XML contexts. It is used most generally when we just want to discuss the structure or display of a document versus the semantics of the document that is the content data found within the structure . In Chapter 13 we referred to the W3C s Semantic Web objective wherein Web search agents can examine standardized metadata to learn about the subject matter in Web resources. Semantics as we use it here has a narrower focus the actual meaning of numbers constants variables and operators in the mathematical expressions in a document. The Web community clearly needs a way to render and transmit mathematical expressions accurately and quickly. As more research and commerce are conducted and coordinated via the Web the Web community has spotlighted the last issue the development of math and science objects that are active that provide for the automatic processing and manipulation described previously. Early Visual Presentation Solutions Since the mid-1970s the IT industry has developed several visual presentation solutions such as eqn. Developed in 1975 by Bell Labs for use with the UNIX typesetting system named troff. It was an influence on EzMath which is demonstrated in the Chapter 16 lab exercises. TeX. Developed by D. Knuth of Stanford University in the late 1970s. Became the most popular method for electronic typesetting of mathematical expressions. Provides more control over typesetting details and relies heavily on macros. Available as freeware or shareware or from commercial vendors. LaTeX. Developed by L. Lamport in the mid-1980s. Available by anonymous FTP from the LaTeX3 Project which has continued development Web site at . AMS-TeX. Developed by the American Mathematical Society in the 1990s. A set of fonts and macros .
