Xerox Document Services Document Model

1.1 Background

While electronic documents are a dominant and increasing part of the business world, paper documents have not disappeared, and are in fact increasing in absolute terms. While paper documents offer significant advantages in reading, understanding, some kinds of editing, under certain legal conditions, and in the many other affordances of paper, electronic documents are undeniably the coin of the realm in today's business world. Increasingly, business is dealing with compound documents containing both paper and electronic forms. Storing copies of paper documents electronically gives the best of both worlds, allowing the full ease of electronic document operations to be applied to paper documents, yet allows paper access to electronic documents when necessary and valuable. Capturing paper documents in a usable electronic form — and being able to print, copy, or otherwise operate on them from a desktop computer or a networked document appliance — is of great importance to business.

Documents are most valuable when they are , and can serve as memory association triggers. Many paper documents are situated by physical filing systems and human spatial memory, and not all of the information about the documents (meta-data) is in a form that is easily captured electronically. Electronic documents are usually situated by use of meta-data, or named properties of documents. Scanned electronic documents rapidly lose their value if the association between the document identity, document content, and documnt meta-data is lost.

Capturing paper documents has traditionally been an expensive business process. First, documents are scanned, and saved to removable media or an extranet, then checked for quality and possibly re-scanned, then sent to a "coding bureau" to have meta-data typed in and associated, and then finally shipped to a document repository. The total cost of this cycle is tremendous, as information present at each step is lost before the next and must be recreated, at great cost. In summary, the process of capturing scanned document meta-data for scanned documents is labor intensive, and is best done closest to the source of the documents, as it can be expensive to recover the meta-data at a later date, or by someone other than the document's owner.

Document Services re-envisions the paper-electronic boundary, and uses a capture technology that associates the meta-data with the document as soon as possible, when the document is still situated, and gives immediate feedback about the document quality, thus reducing the cost of both the capture and QA steps of document capture.

A typical paper business document achieves importance by being in the hands of a knowlege worker, who not only knows the value of the document, but also knows the context. Thus, he or she is an idea person to capture the meta-data associated with the value and context of the document, and to approve the quality of its capture. Unfortunately, traditional document capture technologies are cumbersome and time-consuming, so it is not cost-effective to pay knowledge workers to handle their own documents. A Document Services-based system aims to reduce the cost of handling and capturing documents to produce rich repositories of electronic knowledge, at low cost, by integrating the handling of paper and electronc documents into the normal work practice of knowledge workers, with operations that are defined in their terms, rather than focused on traditional scanning procedures.

This specification defines one important part of a compound paper-electronic document processing system, the Xerox Document Services Document Model, which is an XML instance document modeling the documents under processing, and holding their rendition and meta data information. Other key components of a document processing system are listed here, but are beyond the scope of this paper: a Document Service Orchestrator, which accepts a workflow definition XML document describing a process for performing document services. Document Services include capturing a document, adding meta-data to it, performing quality assurance, apply transformations such as OCR to both renditions and meta-data, storing in a document repository and dispatching the document to a target such as a printer or e-mail address.

Manipulation of the XDSDM by document services is done through XPath expressions (see [XPath 1.0]), as is done in XForms (see [XForms 1.0]). In fact, the XDSDM itself is similar to the instance document in XForms, but instead of being modified through user interface controls, it is modified by document services.

Document Services that operate on the XDSDM can retrieve documents, metadata, and renditions from the model by using XPath expressions, and can update the model to add or change renditions or metadata through the use of XML Events (see [XML Events]) with DOM mutation actions, whose location is specified by XPath expressions and whose contents are described in the event payload. Unfortunately, the XML Events specification does not specify action handlers, and so the DOM mutation handlers are presently implemented as shorthand for an XSLT transformation (see [XSLT 1.0]) in which the action handler body is an transformed into an XSLT transformation, which is then applied to the identified element document in the XDSDM with the event payload available as a the result of an XSLT extension function in XPath expressions.

The document content itself is not stored in the model, but is refererred to by URI (see [RFC 2396]), and is compatible with the XForms 1.0 element upload and XForms 1.0 submission methodmultipart-related serialization.

1.2 Documentation Conventions

Throughout this document, the following namespace prefixes and corresponding namespace identifiers are used:

doc:The Document Services Document Model namespace (http://www.example.com/document) A.1 Schema for Document Model
ri:The Document Services Rendition Information namespace (http://www.example.com/rendition-info) A.2 Schema for Rendition Information
xsd:The XML Schema namespace (http://www.w3.org/2001/XMLSchema)[XML Schema part 1]
xsi:The XML Schema for instances namespace (http://www.w3.org/2001/XMLSchema-instance)[XML Schema part 1]
my:Any user defined namespace

2.1 Common Attributes

2.2 Elements related to documents

2.3 Elements related to renditions

2.4 Elements related to Meta Data