mhe - consultants for document and datament technologies xml - what it means to you william j....

MHE - Consultants for Document and Datament Technologies

XML - What It Means To You

William J. “Bill” McCalpin

EDPP, CDIA, MIT, LIT

Principal

MHE


Introduction

The Hegelian Dialectic


Thesis, Antithesis, SynthesisIn the philosophy of Hegel,

these words show the inevitable transition of thought, by contradiction and reconciliation, from an initial conviction to its opposite and then to a new, higher conception that involves but transcends both of them


The Hegelian Dialetic• Thesis: Most business have well-established,

productive legacy systems• Antithesis: XML is springing forth

everywhere• Synthesis: XML will be integrated with

legacy systems - enhancing some processes, changing many others, and eliminating some altogether

• In short, XML will affect what you do


How To Relate XML to Everyman

• You might think that XML is too esoteric for most people to understand

• But XML is based on the basic human need exchanging information

• XML couples the communication skills we have used over the last several thousand years to modern, Internet technology

• So how can you understand it?


Sex And The Single Pixel

Or, How To Explain XML Through Human Relationships


Men Are From MarsWomen Are From Venus

• Author John Gray has the best selling book describing the difficulties of communication

• Why would there be such difficulties?


Communication Difficulty #1

• In order for any communication to take place, both parties must share the same fundamental mechanism which carries information

• For example, in writing, if a boy and girl don’t even share the same writing schemes, they can’t possibly understand...


Chinese Characters vs Latin Alphabet

“I Love You”


Underlying Structure of XML• Text characters• Tags are delimited by “<“ and “>”, i.e.

<xml>• Ending tags have “/”, e.g., </xml>• Parameters are indicated by double quotes,

e.g., <PAPER track="Application">• XML is a series of tags and data, e.g.,

<STATE>Texas</STATE>



• Once both parties agree to the fundamental syntax, then both parties must next agree to the words to be used

• In the case of XML, how do both parties know that <STATE> means a political subdivision and not one of {gas,liquid,solid}?


A Date Gone Bad• One evening in the

hotel lobby bar, two young Italian men spend a while talking to an attractive Venezuelan girl...and her aunt

• They spoke Italian and she spoke Spanish, but they communicated passably


A Date Still Going Bad

• However, the aunt wanted to go up to her room with her niece

• The Italians wanted to take the young lady out dancing...

• So they asked her:


Oops

• What the boys said:

“Vuoi andare con noi ‘sta sera?

• What the young lady needed to hear:

“Quisieras ir con nosotros esta tarde?”


Miscommunication

• Even though Italian and Spanish use the same sounds, the same grammar, and have a common ancestry in Latin, some words are different

• Unfortunately, the most common words in both languages are likely to be the most different


The Cost Of Data Differences“NASA lost a $125

million Mars orbiter because one engineering team used metric units while another used English units for a key spacecraft operation...” CNN 9/30/99


XML “Words”• HTML has a certain

number of fixed tags - everyone knows what they are, but they can’t be augmented

• In XML, everyone can make up their own tags to suit their needs - but how do we avoid a Tower of CyberBabel?



• Even when you agree to common tags, you still need to agree to a common understanding

• In XML, the Schema (now replacing the DTD) defines what tags are allowed to describe a particular collection of data

• For example, in the field of human relations, what is a “date”?


One DTD For A “Date”

• A woman thinks:– Invitation - formal

– Dress-up - nicely

– Eat out – dinner with wine at nice restaurant

– Entertainment – see a movie

– Private moment – good night kiss

• <!DOCTYPE Date [• <!ELEMENT Date (Invitation, Dress,

Meal, Entertainment+, Intimacy) >• <!ELEMENT Invitation (#PCDATA) >• <!ELEMENT Dress (#PCDATA) >• <!ELEMENT Meal (#PCDATA) >• <!ELEMENT Entertainment

(#PCDATA) >• <!ELEMENT Intimacy (#PCDATA) >


A Woman’s View Of A “Date”

<date>

<invitation>Telephone call</invitation>

<dress>Long dress</dress>

<meal>4-star restaurant</meal>

<entertainment>the theatre</entertainment>

<intimacy>A passionate, romantic kiss</intimacy>

</date>


Another DTD For A “Date”

• A man thinks:– Eat out – six-pack

– Private moment – necking

• <!DOCTYPE Date [• <!ELEMENT Date (Meal,Intimacy+) >• <!ELEMENT Meal (#PCDATA) >• <!ELEMENT Intimacy (#PCDATA) >


A Man’s View Of A “Date”

<date>

<meal>six-pack of beer</meal>

<intimacy>necking

</intimacy>

</date>


When Men And Women Agree

<date>

<invitation>Telephone call</invitation>

<dress>Long dress</dress>

<meal>4-star restaurant</meal>

<entertainment>the theatre</entertainment>

<intimacy>A passionate, romantic kiss</intimacy>

</date>

<date>

<invitation>Honking

</invitation>

<dress>Not the shirt he changed the oil in</dress>

<meal>food and beer</meal>

<entertainment>rent a video</entertainment>

<intimacy>A passionate, romantic kiss while necking</intimacy>

</date>


Presentation

• In human relationships, it’s normal for someone to present themselves in the best light possible

• We try to minimize any deficiencies while maximizing our positive attributes

• Thus, we would like to present ourselves as:


Author’s View


Original Data


XSL• XSL - eXtended Style Language

• XSL is derived from CSS - Cascading Style Sheets

• XSL can enable the author to create one or many views of XML

• Since XSL can be separate from the XML object, the reader can apply the presentation information as well as the author



• When all we had was paper and film, the author alone controlled the presentation of the data

• One of the great advantages of electronic formats is that the presentation of data can now be put into the hands of the reader

• How can we describe this in the field of human relationships?


Three Bachelors To Choose From

• Our contestant has to choose from 3 bachelors

• But if the information about the bachelors were on paper, then the information would be presented only one way


How To Choose?

Bachelor List

But with XML (and other electronic formats like HTML), our contestant can view the information in different ways, to help her make her decision


The Datamenttm


The “Datament”

• Efforts to expand the meaning of “document” to include all manner of electronic formats have been unsuccessful

• Hence, we have invented the concept of the “datament

tm, which is a “organized

collection of information in time” which can be viewed by both human and machine


The Readers Of Dataments• Because the datament is in XML,

presentation information can be ignored and the data directly extracted from the appropriate tags

• Dataments can also carry one or more “views” of the data.– One view should be the original static view– Another view can allow the reader flexibility


Why Multiple Views?• Think of a 60,000 page phone bill - it’s

impossible to make any sense of it without sorting, hiding, etc. like with a spreadsheet

• On the other hand, if one reader alters the view, then another reader might miss important information, hence there is a “default” view

• This default or author-centric view will also help satisfy regulatory authorities



• Without resorting to bars, how can people easily find compatible partners?

• Now think about all the classified ads you might have to pore through in order to find someone who interests you

• Fortunately, personals have a standard indexing method


A Personal Ad

• DWF - “divorced white female”

• SBM - “single black male”

• WBFP - “wood burning fireplace” - oops

• This system works because there is a standard method of indexing personals

• If the authors of the classifieds made up their own indexes, think of the confusion:


Apples And Oranges

• “nice DWM seeks girl who wants a good time”

• “cons w trvst in spc prog seeks swng aln to tk to their ldr”


Extending XML

• XML is not only a useful way to accurately describe people, er, information, but it can be use as the basis of many other standards

• For example, RDF stands for “Resource Description Framework ”, that is, a framework for describing and interchanging metadata (i.e., information about information).


XML

• XML has a common underlying syntax

• Industries and groups can create XML tags which suit their needs

• XML enables both the author and the reader to control the presentation

• But let’s digress...


What Is A Document?

• The American Heritage Dictionary defines a document as “information in writing placed on a medium such as paper, often used as a record.”

• Documents have been placed on clay tablets, gold leaf, animal skins, all types of paper, microfilm, optical storage, and so on


Information And Presentation

• In every case, the document represents a fundamental union of information and presentation

• But “presentation” presumes that the primary audience for the document is a human being

• With the coming of the Internet, this is no longer the case


The Curse Of Presentation• Composition

products require that you specify a printer, even before you know where the document will print


Why Are Print, Image, And Presentation Formats

Incompatible?


Printing And Imaging Formats

• Many printing formats: AFP, Metacode, DJDE, XES (UDK), PostScript, PCL, etc.

• All formats use external resources like fonts, forms, graphics, etc., although sometimes inconsistently

• Most are escape-sequence based, some are formal data architectures, and some are almost programming languages


Printing And Imaging Formats

• Many imaging formats - while most used CCITT Group 4 for image compression, most also had proprietary data wrappers

• Later systems adopted text-based formats such as PDF, although storing other print streams is not unknown

• Systems which store text-based formats must wrestle with resource issues


Different Print Formats• Why do printers have different formats?

Because of physical constraints imposed by the hardware:– resources reduce the amount of data sent through

pipeline to printer– pages must be imaged in less than a fraction of a

second– complex graphics can be developed on the

printer, but this needs a special language


Different Imaging Formats• Why do imaging systems have different

formats: because of physical constraints imposed by the hardware:– Mass storage was expensive

– Indexing schemes were too close to the application

– Text is avoided sometimes because of resource issues

– Interoperability with other products an issue


Result

• In each case, data architecture decisions were made in order to enhance some aspect of legibility of the stored objects.

• If there were no requirement to present the information (to a human reader), then the requirement for custom data formats for each vendor would probably disappear!


Universal Literacy

Who’s reading our documents?


The Road To Universal Literacy

• First, only the few could read

• After the printing press, the many began to read

• Eventually, educational reforms brought the ability to read to all


Literacy In The Internet Age• Can there be a spread of literacy beyond

“all”?

• How many webpages have you ever read?

• You will never be able to keep up with the Web – alone

• There are already an estimated 98,685,000 host computers on the Internet (www.mids.org)


Intelligent Agents

• Just around the corner is software that will read the Web for us – not search, but read

• So we have to spread literacy to an audience beyond “all” – people, that is

• Does increased quality in presentation mean better computer literacy?


Noise On The Net• Think of the average webpage:

three dimensional spinning objects marquees scrolling across the bottom multiple frames bookmarks audio

• These items are all designed to attract the eye – your eye

• This does nothing for the machine reading the webpage


Two Important Truths

• There are two important truths of the Internet era:– Documents which are read by humans need to

be dynamic in their presentation– Documents which are read by computers don’t

need any presentation information at all

• XML totally divorces presentation from information!


What Have We Learned About XML?


XML Summary

• XML uses tags to describe data– <state>Texas</state>

• Businesses and non-profits join together to build DTD/Schemas to describe data objects in their spaces– <?xml version="1.0" encoding="ISO-8859-1"?>– <!DOCTYPE claim [


XML Summary

• An XML “document” contains information for a particular event or transaction which can be understand by both parties

• XML ‘documents’ can be intended for two types of readers: human and machine


XML Summary

• XML ‘documents’ intended for a machine do not require any presentation information

• XML ‘dataments’ carry the information which enables both static (author-centric) and dynamic (reader-centric) presentations, using XSL


What Will You Tell Your Boss?“Well, this dude named Hegel met Drew Carey

while speaking Spanish in an Italian bar when they met a transvestite space alien who was looking for a missing NASA satellite who told them that women were not either from Venus and that Mimi and Pierce Brosnan were on a date but each was reading different versions of the same menu because it was a datament in XML.”


Reference

• www.w3c.org - the official World Wide Web Consortium site (you’ll find links to the XML spec here)


William J. “Bill” McCalpin

EDPP, CDIA, MIT, LIT

Principal, MHE

1400 Cheyenne Dr.

Richardson, Texas 75080-3921

972-231-3660 (v) 972-690-4521 (f)

[email protected]