Technology is defined as a set of techniques and knowledge that help achieve practical goals. Some of the fields of technology include software, physical objects, and intangible tools. The term technology is also used to define the product of an effort or endeavor. There are many different technologies in use today.
PDF is a format that allows documents to be distributed in a manner that is accessible to individuals with disabilities. This format was created by Adobe Systems as part of their efforts to drive the digital document format into the 21st century. Its features include support for text to speech facilities, a full check for accessibility, and the ability to reflow for large print display. A PDF file can be produced directly from application programs or indirectly through conversion from other file formats.
The logical structure of a PDF document is described by a hierarchy of objects. Each object contains information about the content and attributes of the structure element it represents. These components are incorporated into the logical structure in a manner similar to standard document markup languages. In fact, these features are based on a concept called Document Object Model (DOM). Since DOM was first introduced in PDF 1.3, it has been enhanced to support caret support, enhanced selection, and improved focus support.
An example of the logical structure in a PDF document is a structure tree. The root of the structure tree is represented by the StructTreeRoot entry in the document catalog. Its children are represented by the K entry.