clarke, r. j (2001) l909-05: 1 office automation & intranets buss 909 lecture 5 from storage to...
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Clarke, R. J (2001) L909-05: 1
Office Automation & Intranets
BUSS 909
Lecture 5From Storage to
Interchange: Standard Generalized Markup
Language (SGML)
Clarke, R. J (2001) L909-05: 2
Notices 1
Assignment 1 is due next weekAssignment 2 will be available from
the Intranet next week. As with the current assignment, there are some administrative requirements that must be fulfilled by all students- described next lecture
Clarke, R. J (2001) L909-05: 3
Notices (2)
to accommodate the new T1 tutorial for this subject, my Consultation Time C1 which was 14:30-16:30 is now 13:30-15:30 40.242 remaining in effect until the end of session
Clarke, R. J (2001) L909-05: 4
Agenda
Types of MarkupStylesheets & Markup (wrt HTML)SGML StandardSGML ExampleSGML BenefitsAdopting SGML
Clarke, R. J (2001) L909-05: 6
Types of Markup
the following slides show an extract from a Vincent motorcycle repair manual to illustrate the types of markup which can be used on a document
but just in case you don’t know what a Vincent motorbike looks like, here is a picture of a 1994 rebuild of the 1959 classic...
Clarke, R. J (2001) L909-05: 8
Types of MarkupProcedural Markup
the following two slides shows an extract from a Vincent motorcycle repair manual showing the procedural markup
this kind of markup tells a workprocessor or other related system how to render (or display) the page
Clarke, R. J (2001) L909-05: 9
Procedural Markup
Centre; 10pt Times-Roman
Down 10pt; centre;12pt. Helvetica Bold
Down 15pt.; first line indent 0.3 inch; 12-pt. Times Roman
Down 22pt.; centre; 10-pt. Helvetica Medium
Down 5pt.; centre; 12-pt Helvetica Bold
Down 10pt.; 12-pt Times Roman run-in bold
(Source: Nicholson Brothers Motorcycles Ltd. 1994)
Clarke, R. J (2001) L909-05: 10
Procedural Markup (continued)
Down 22pt.; centre; 10-pt. Helvetica Medium
Down 5pt; centre;12pt. Helvetica Bold
Down 15pt.; 12-pt. Times Roman
Down 10-pt.; indent 0.32 inch first line indent 0.325 inch right align 0.2 inch; tab left alighed 0.325 inch 12-pt. Times Roman
(Source: Nicholson Brothers Motorcycles Ltd. 1994)
Clarke, R. J (2001) L909-05: 11
Types of MarkupDescriptive Markup
the following two slides shows an extract from a Vincent motorcycle repair manual showing the descriptive markupthe descriptive markup used in this example
identifies the structure of the documentthis type of markup could be used to describe
the data or information structure of the document
Clarke, R. J (2001) L909-05: 12
Descriptive Markup
chapnum (Chapter number)
title
titlepara
sectnum(Section Number)
title
labitem (Label list item)
(Source: Nicholson Brothers Motorcycles Ltd. 1994)
Clarke, R. J (2001) L909-05: 13
Descriptive Markup (continued)
sectnum (Section number)
title
sectnum (Section number)
listitem (List item)
(Source: Nicholson Brothers Motorcycles Ltd. 1994)
Clarke, R. J (2001) L909-05: 15
Stylesheets and Markup
for any real document based system, we need to:design the content of the document-
descriptive markup- independent of its lookdesign the look of the document- procedural
markup- independent of its contentwe need to relate them together because
content must be displayed- this is done by using stylesheets
Clarke, R. J (2001) L909-05: 16
Stylesheets and Markup
Focus: Information System
Function: How to display or render the elements of a document
Stylesheet
Focus: Assist users/readers in interpreting the meanings of a document by means of a consistent visual look
Function: providing a consistent look and feel- procedural issue- to meaningful elements of a document- descriptive issue.
Focus: Human Users
Function: What is the meaning of an element in a document, what purpose does it serve for the organisation
Descriptive MarkupPrescriptive Markup
Clarke, R. J (2001) L909-05: 17
Stylesheets and MarkupHyper Text Markup Language
In principle, HTML as a standard attempts to provide structural meaning to page content- the purpose of tagswhat is enclosed between <P>…</P> is
interpreted as a paragraph
unfortunately, structural markup is only a limited form of descriptive markup
Clarke, R. J (2001) L909-05: 18
Stylesheets and MarkupHTML 4.0 Specification (1)
unfortunately, most web page authors concentrate only on the look of the page (by heavily using the procedural markup oriented tags)
the introduction of the HTML 4.0 specification attempted to distance the content of web pages from formatting issues
Clarke, R. J (2001) L909-05: 19
Stylesheets and MarkupHTML 4.0 Specification (2)
this standard encouraged reduction in the use of formatting (procedural) markup like <FONT>…</FONT> and <H1>...</H1>, <H2>...</H2> etc. tagsformatting was assigned to a separate
standardization effort related to content style- Cascading Style Sheet (CSS)
provided the means to pass the decision as to how a paragraph looks to a style definition
Clarke, R. J (2001) L909-05: 20
Stylesheets and MarkupLink between Stylesheet and Content
In HTML, the link between a style sheet and the content it influences is either:tag name of the HTML element that
holds the content or,an identifier associated with the element
by way of an attribute (eg. ID or a CLASS attribute)
Clarke, R. J (2001) L909-05: 21
Stylesheets and MarkupCascading Style Sheets
Cascading Style Sheets (CSS) allows authors to define style rules to each HTML element and these rules may apply to either:single elementsa related group of elements, or toall elements of a particular type (such
as all P elements)
Clarke, R. J (2001) L909-05: 22
Stylesheets and MarkupStyle Rules in CSS (1)
style rules influence the rendering of elementscolour, alignment, border, margins, and
padding between borders and contentcan also control special items eg.
whether Ordered List (OL) elements use bullet symbols, letters or roman numerals
Clarke, R. J (2001) L909-05: 23
Stylesheets and MarkupStyle Rules in CSS (2)
every style rules have two parts:one or more elements or groups of elements
that have style sheets defined for themone or more style sheet attributes that apply
to the elements
then need to relate or bind stylesheets to HTML elements (eg. to all P elements)- several possible approaches
Clarke, R. J (2001) L909-05: 24
Stylesheets and MarkupApproaches of Binding
two major approaches to binding stylesheets to HTML elementsin-document stylesimporting external stylesheets
the choice of approach depends on:the size and complexity of the web sitethe size of the development team user community diversity and expertise
Clarke, R. J (2001) L909-05: 25
Stylesheets and MarkupIn-Document Style Binding (1)
:
<BODY>
<H1 STYLE= “color:red; text transform:capitalize”>Some heading</H1>
<P STYLE=“color:blue”>Some paragraph text</P>
:
<BODY>
One form of In-Document Style Binding associates a style declaration to an HTML element using the elements’ STYLE attribute
Usage: convenient if style rules are
few and simple difficult to maintain in large
sites as changes must be made throughout the HTML file
Note: almost every HTML element can have a STYLE attributeassociated with it
Clarke, R. J (2001) L909-05: 26
Stylesheets and MarkupIn-Document Style Binding (2)
Another form of In-Document Style Binding is to define and group together all style rules between <STYLE>… </STYLE> tags
Usage: better option when trying to
maintain a moderately complex page
promotes modular design and implementation of page
<HTML>
<HEAD>
<STYLE TYPE =“text/css”>
<!--
H1 {color:red; text-transform:capitalize}
P {color:blue}
-->
</STYLE>
:
:
:
<BODY>
<H1>Some heading</H1>
<P>Some paragraph text</P>
</BODY>
</HTML>
Note: style rules are enclosed in HTML comments to prevent older browsers from trying to render them
Clarke, R. J (2001) L909-05: 27
Stylesheets and MarkupBinding using External Stylesheets
Define and apply an external style sheet file to one or more HTML files
the external style sheet file (above, left) contains only rules no HTML tags
Usage: promotes a consistent look
similar to work processor style sheets
separates the documents’ structure and look
Note: these style rules are stored in the file called mystyles.css
H1 {color:red; text-transform:capitalize}P {color:blue}
<HTML><HEAD><LINK REL=STYLESHEET TYPE=“text/css” HREF=“mystyles.css”>:</HEAD><BODY><H1>Some heading</H1><P>Some paragraph text</P></BODY></HTML>
Note: rules are applied to HTML file on the fly
Clarke, R. J (2001) L909-05: 28
Stylesheets and MarkupDifficulties with HTML (1)
While the CSS Level 1 is consistent across major browsers, it doesn’t provide exact positioning of elements on a page
the CSS Level 2 standard supports exact positioning but there are differences in implementation across major browsers
CSS Level 2 has many advantages but in order to preserve the same look developers may be forced to use Level 1- or undertake a major development task!
Clarke, R. J (2001) L909-05: 29
Stylesheets and MarkupDifficulties with HTML (2)
there is a much more serious problem:the stylesheet and descriptive markup capabilities
of HTML 4.0 and DHTML (HTML 5.0), were not built into it from the start
describing the structure is not the same thing as descriptive markup
users cannot create there own tags based on meanings (semantics)- for example no tags for PART NUMBER or COURSE- HTML not extensible
Clarke, R. J (2001) L909-05: 30
Stylesheets and MarkupDifficulties with HTML (3)
on the Internet simplicity wins over efficiency- the Web has grown because its core standards are simple:proof of this is that HTML is itself written
using another standard for describing documents- this standard is called SGML
SGML has also been used to develop a standard likely to replacement HTML on the web- XML described in Lecture 13
Clarke, R. J (2001) L909-05: 32
SGML Standard
internationally recognised standard (ISO 8879) for describing and enforcing structure and properties onto data in computer base information systems, including semi-structured datacompletely descriptive markup system for
document contentopen environment for the interchange of a
portable generic format between platforms
Clarke, R. J (2001) L909-05: 33
SGML StandardFeatures (1)
major features: syntax for text processing stylesheets extensible document description language meta-language for defining document types
text media support: text is coded according to its meaning- can be
used in way not originally envisioned tagging language database language for text
Clarke, R. J (2001) L909-05: 34
SGML StandardFeatures (2)
media processing applications: foundation for multimedia and hypertext- HyTime
(an ISO standard) is an SGML application that knows about multimedia, time-based events, synchronisation
general computational features: handles logical structures (conditional
documents) notation for structures (eg. hierarchies):
sequences, repetitions and selections
Clarke, R. J (2001) L909-05: 35
SGML StandardFeatures (3)
other aspects:general file linking and addressing
schemeopen document representation
language for any system architecturesupports open inter-communication
regardless of hardware platforms and software applications
Clarke, R. J (2001) L909-05: 36
SGML StandardInstances & Document Type Definition
An SGML document is text only, but has the following structure:an document instance containing the
dataa document type definition (DTD)
defining what data elements can be in the document, and how these data elements relate to each other
Clarke, R. J (2001) L909-05: 37
SGML Standard Document Instances
document instances contain data and markup (called tags):both data and tags are in ASCII format- read
by any applicationtags are distinguishable from data: tags
always have pairs of <> bracketssome system specific data can be inserted
into the instance using special tags- removes the need for control codes etc
Clarke, R. J (2001) L909-05: 38
SGML StandardDocument Type Definition (1)
can be stored at the beginning of the document or externally in a separate file (generally the latter)
consist of all the formal definition of the elements, structures, and rules for marking up a given type of SGML document
Clarke, R. J (2001) L909-05: 39
SGML Standard Document Type Definitions (2)
comprise rules and relationships that define how the different elements within a document relate to each other:specify the order in which headings occurwhich elements are allowed under each
headingthe order and frequency with which elements
should appear
Clarke, R. J (2001) L909-05: 40
SGML Standard Document Type Definitions (3)
specifies the permitted document elements eg. ‘Chapter’, ‘Heading’, ‘Definition-entry’,
‘Defined-work’, ‘Definition’ and ‘See-also’
each element typically has a content model stating its required or permitted contents. eg. the content model for ‘Definition-entry’ would
state that it must have only one ‘Defined-word’ and ‘Definition’
‘Defined-word’ and ‘Definition’ must also be described by content models
Clarke, R. J (2001) L909-05: 41
Document Type DefinitionExtract of an SGML Memo DTD
<! -- DTD for simple office memoranda --->
<! --
<! ELEMENT MEMO -- ((TO & FROM), BODY, CLOSE?) >
<! ELEMENT TO -0 (#PCDATA) >
<! ELEMENT FROM -0 (#PCDATA) >
<! ELEMENT BODY -0 (P) * >
:
:
<! ATTLIST MEMO STATUS (CONFID | PUBLIC) PUBLIC >
:
:
Clarke, R. J (2001) L909-05: 42
SGML Processing Systems (1)
read a document instance, and refers to a DTD to find out how to process itaspects of the document instance such as
format of the page, fonts spacing etc. are not defined in SGML (a distinction between PostScript for example and SGML)
must exist in heterogeneous environments where not all documents are in SGML
Clarke, R. J (2001) L909-05: 43
SGML Processing Systems (2)
SGML Data SGML DTD
ApplicationLibrary
Application Output
SGML Parser
SGML Processing System
Clarke, R. J (2001) L909-05: 44
SGML Processing Systems (3)
TagApplication
SGMLApplications
BitmapEdit/Convert
Non-SGMLEditing System
SGML Edit/Convert
New Data
New Data
Legacy Documents
GraphicsFiles
SGMLFiles
Clarke, R. J (2001) L909-05: 45
DSSSL
Document Style Semantics and Specification Language (DSSSL)is the ISO international standard (ISO
DIS 10179) which addresses the need for detailed, typographically sophisticated, specification of layout and composition
independent of particular formatting systems or processes
Clarke, R. J (2001) L909-05: 47
SGML ExampleInformational Content Markup
the following two slides shows an extract from a Vincent motorcycle repair manual
show the informational content markup using SGML
note that SGML tags are usually shown in the form <…> followed by </..>
Clarke, R. J (2001) L909-05: 48
Information Markup
(Source: Nicholson Brothers Motorcycles Ltd. 1994)
CHAPTER (BIKETYPE=”Vincent”)
INTRO Although the design of the Vincent differs substantially from conventional motorcycles,operating procedure and maintenance requirements are comparatively similar. /INTRO
LUBE
SUPPLIES
ITEM Grades of Motor Oil /ITEM
DETAIL CROSSREF [TARGET=”PG142”] /CROSSREF /DETAIL
ITEM Motor Lubrication /ITEM
DETAIL Oil supply is contained in tank which forms the
LOCATION top frame member. /LOCATION Motor oil tank capacity is
CAPACITY [UNITS=”QUARTS”] 3. /CAPACITY /DETAIL
ITEM Motor Oil Filter /ITEM
DETAIL A fabric filter is located at
LOCATION front of crankcase below the magneto. /LOCATION /DETAIL
ITEM Gearbox Oil /ITEM
DETAIL Oil capacity is
CAPACITY [UNITS=”PINTS”] 3. /CAPACITY /DETAIL
/SUPPLIES
/LUBE
Clarke, R. J (2001) L909-05: 49
Information Markup (continued)
(Source: Nicholson Brothers Motorcycles Ltd. 1994)
TIMING
NOTE Due to the Vincent’s uneven firing interval, timing should be checked on both cylinders./NOTE
METHOD
STEP [ ] PARA Set breaker points to POINTGAP [UNITS=”INCHES”] .012/POINTGAP fully open with a TOOL screwdriver. /TOOL /PARA/STEP
STEP [ ] PARA Using TOOL degree plate, /TOOL set the flywheel so that thedegree wheel reads at KEYVALUE [UNITS=”DEGREES”] 37-38 /KEYVALUEbefore TDC. /PARA /STEP
STEP [ ] PARA With a piece of wood, block the automatic advance in the fully advancedposition. /PARA /STEP
STEP [ ] PARA Using a TOOL hex key, /TOOL revolve magneto via the breakerpoint assembly until points just commence to separate. /PARA /STEP
STEP [ ] PARA Fix the gear to magneto shaft, by placing TOOL box wrench /TOOLover nut and giving sharp rap with TOOL hammer. /TOOL /PARA /STEP
/METHOD
/TIMING
/CHAPTER
Clarke, R. J (2001) L909-05: 51
SGML Benefits
DTD structure forces the user to focus on document content not format
SGML helps the authors by:suggesting the correct structure of
different document typesenforces the correct structure: if an author
attempted to put in non-standard material, the application would refuse to accept it
Clarke, R. J (2001) L909-05: 52
SGML Benefits
Data Managementcommon data repository for the
enterprisestandardised formatting for informationminimise data duplicationcontrol/check data qualitymaximises the benefit of data entry and
authoring
Clarke, R. J (2001) L909-05: 53
SGML Benefits
facilitates data exchange within an enterprise (Intranets)prevents islands of information forming
within the organisation (that is information trapped within specific functional areas)
prevents an ‘isolationist mentality’ forming within specific functional areas (‘marketing’ data rather than organisational asset)
Clarke, R. J (2001) L909-05: 54
SGML Benefits
facilitiates data exchange between an organisation and business partners (Extranets; EDI) promotes participation between partnersreduces costs, improves performancestreamlines operations and maangement
practices, reduces ‘bottlenecks’
Clarke, R. J (2001) L909-05: 55
SGML Benefits
Video Case Studies about EDINote that SGML could well have been
an enabling technology for EDI in these CASE Studies
take notes on how these EDI systems were negotiated- what are the Tactical Strategic and Operation implications suggested in these cases
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