Transcript Systemic Semiotic Design Practice:
BUSS 909 Office Automation & Intranets
Lecture 5
From Storage to Interchange:
Standard Generalized Markup Language (SGML)
Clarke, R. J (2001) L909-05: 1
Notices
1
Assignment 1 is due next week
Assignment 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: 2
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: 3
Agenda
Types of Markup
Stylesheets & Markup (wrt HTML)
SGML Standard
SGML Example
SGML Benefits
Adopting SGML Clarke, R. J (2001) L909-05: 4
Types of Markup
Clarke, R. J (2001) L909-05: 5
Types of Markup
the following slides show an extract from a
Vincent motorcycle repair manual markup
to illustrate the
types of
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: 6
1994 Vincent Motorcycle
Clarke, R. J (2001) L909-05: 7
Types of Markup
Procedural 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: 8
Procedural Markup Centre; 10pt Times-Roman Down 10pt; centre; 12pt. Helvetica Bold Down 15pt.; first line indent 0.3 inch; 12-pt. Times Roman
CHAPTER NINETEEN
VINCENT SERVICING
Although the design of the Vincent differs substantially from conventional motorcycles, operating procedure and maintenance requirements are comparatively similar.
Down 22pt.; centre; 10-pt. Helvetica Medium Down 5pt.; centre; 12-pt Helvetica Bold Down 10pt.; 12-pt Times Roman run-in bold
Section 1
LUBRICATION Grades of Motor Oil
- Refer to page 142.
Motor Lubrication
- Oil supply is contained in tank which forms the top frame member. Motor oil tank capacity is 3 quarts.
Motor Oil Filter
- A fabric filter is located at front of crankcase below the magneto.
Gearbox Oil
- Oil capacity is 3 pints.
(Source: Nicholson Brothers Motorcycles Ltd. 1994) Clarke, R. J (2001) L909-05: 9
Procedural Markup (continued) Down 22pt.; centre; 10-pt. Helvetica Medium Down 5pt; centre; 12pt. Helvetica Bold Down 15pt.; 12-pt. Times Roman
Section 2
IGNITION TIMING
Due to the Vincent’s uneven firing interval, timing should be checked on both cylinders.
1. Set breaker points to .012” gap fully open with a screwdriver.
2. Using degree plate, set the flywheel so that the degree wheel reads at 37-38 degrees before TDC.
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
3. With a piece of wood, block the automatic advance in the fully advanced position.
4. Using a hex key, revolve magneto via the breaker point assembly until points just commence to separate.
5. Fix the gear to magneto shaft, by placing box wrench over nut and giving sharp rap with hammer.
(Source: Nicholson Brothers Motorcycles Ltd. 1994) Clarke, R. J (2001) L909-05: 10
Types of Markup
Descriptive Markup
the following two slides shows an extract from a Vincent motorcycle repair manual showing the
descriptive markup
the descriptive markup used in this example identifies the
structure of the document
this type of markup could be used to describe the
data or information structure
of the document Clarke, R. J (2001) L909-05: 11
Descriptive Markup chapnum (Chapter number) title titlepara
CHAPTER NINETEEN
VINCENT SERVICING
Although the design of the Vincent differs substantially from conventional motorcycles, operating procedure and maintenance requirements are comparatively similar.
sectnum(Section Number) title labitem (Label list item)
Section 1
LUBRICATION Grades of Motor Oil
- Refer to page 142.
Motor Lubrication
- Oil supply is contained in tank which forms the top frame member. Motor oil tank capacity is 3 quarts.
Motor Oil Filter
- A fabric filter is located at front of crankcase below the magneto.
Gearbox Oil
- Oil capacity is 3 pints.
(Source: Nicholson Brothers Motorcycles Ltd. 1994) Clarke, R. J (2001) L909-05: 12
Descriptive Markup (continued) sectnum (Section number) title sectnum (Section number) listitem (List item)
Section 2
IGNITION TIMING
Due to the Vincent’s uneven firing interval, timing should be checked on both cylinders.
1. Set breaker points to .012” gap fully open with a screwdriver.
2. Using degree plate, set the flywheel so that the degree wheel reads at 37-38 degrees before TDC.
3. With a piece of wood, block the automatic advance in the fully advanced position.
4. Using a hex key, revolve magneto via the breaker point assembly until points just commence to separate.
5. Fix the gear to magneto shaft, by placing box wrench over nut and giving sharp rap with hammer.
(Source: Nicholson Brothers Motorcycles Ltd. 1994) Clarke, R. J (2001) L909-05: 13
Stylesheets and Markup
Emphasising HTML Clarke, R. J (2001) L909-05: 14
Stylesheets and Markup
for any real
document based system
, we need to:
design the content of the document-
descriptive markup
- independent of its look
design the look of the document-
procedural markup
- independent of its content
we need to relate them together because content must be displayed- this is done by using
stylesheets
Clarke, R. J (2001) L909-05: 15
Stylesheets and Markup
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.
Prescriptive Markup
Focus
: Information System
Function
: How to
display or render
the elements of a document Descriptive Markup
Focus
: Human Users
Function
: What is the
meaning
of an element in a document, what
purpose
does it serve for the organisation Clarke, R. J (2001) L909-05: 16
Stylesheets and Markup
Hyper Text Markup Language
In principle, HTML as a standard attempts to provide
structural meaning
to page content- the purpose of tags
what is enclosed between
…
is interpreted as a paragraph
unfortunately, structural markup is only a
limited form of descriptive markup
Clarke, R. J (2001) L909-05: 17
Stylesheets and Markup
HTML 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: 18
Stylesheets and Markup
HTML 4.0 Specification (2)
this standard encouraged
reduction in the use of formatting (procedural) markup
like … and
...
,...
etc. tags
formatting was assigned to a
standardization effort separate
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: 19
Stylesheets and Markup
Link 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: 20
Stylesheets and Markup
Cascading Style Sheets
Cascading Style Sheets (CSS) allows authors to define
style rules to each HTML element
and these rules may apply to either:
single elements
a related group of elements, or to
all elements of a particular type (such as all P elements) Clarke, R. J (2001) L909-05: 21
Stylesheets and Markup
Style Rules in CSS (1)
style rules
elements influence the rendering of
colour, alignment, border, margins, and padding between borders and content
can also control special items eg. whether Ordered List (OL) elements use bullet symbols, letters or roman numerals Clarke, R. J (2001) L909-05: 22
Stylesheets and Markup
Style Rules in CSS (2)
every
style rules
have two parts:
one or more
elements or groups of elements
that have style sheets defined for them
one or more
style sheet attributes
to the elements that apply
then need to relate or
bind
stylesheets to HTML elements (eg. to all P elements) several possible approaches Clarke, R. J (2001) L909-05: 23
Stylesheets and Markup
Approaches of Binding
two major approaches
to binding stylesheets to HTML elements
in-document styles
importing external stylesheets
the choice of approach depends on:
the size and complexity of the web site
the size of the development team
user community diversity and expertise Clarke, R. J (2001) L909-05: 24
Stylesheets and Markup
In-Document Style Binding (1) :
Some heading
Some paragraph text
:Note
: almost every HTML element can have a STYLE attribute associated with it
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 Clarke, R. J (2001) L909-05: 25
Stylesheets and Markup
In-Document Style Binding (2)
Note
: style rules are enclosed in HTML comments to prevent older browsers from trying to render them
Some heading
Some paragraph text
Another form of In Document Style Binding is to
define and group together all style rules between tags
Usage:
better option when trying to maintain a moderately complex page
promotes modular design and implementation of page Clarke, R. J (2001) L909-05: 26
Stylesheets and Markup
Binding using External Stylesheets H1 {color:red; text-transform:capitalize} P {color:blue} :
Note
: these style rules are stored in the file called mystyles.css
Note
: rules are applied to HTML file on the fly
Some heading
Some paragraph text
Define and apply an
external style sheet file
one or more HTML files to
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 Clarke, R. J (2001) L909-05: 27
Stylesheets and Markup
Difficulties 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: 28
Stylesheets and Markup
Difficulties 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: 29
Stylesheets and Markup
Difficulties 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: 30
SGML Standard
Clarke, R. J (2001) L909-05: 31
SGML Standard
internationally recognised standard (ISO 8879) for
describing and enforcing structure and properties onto data
in computer base information systems, including semi-structured data
completely descriptive markup system for document content
open environment for the interchange of a portable generic format between platforms Clarke, R. J (2001) L909-05: 32
SGML Standard
Features (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: 33
SGML Standard
Features (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: 34
SGML Standard
Features (3)
other aspects
:
general file linking and addressing scheme
open document representation language for any system architecture
supports open inter-communication regardless of hardware platforms and software applications Clarke, R. J (2001) L909-05: 35
SGML Standard
Instances & Document Type Definition
An SGML document is text only, but has the following structure:
an
document instance
data containing the
a
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: 36
SGML Standard
Document Instances
document instances
contain data and markup (called tags):
both data and tags are in ASCII format- read by any application
tags are distinguishable from data: tags always have pairs of <> brackets
some 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: 37
SGML Standard
Document 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: 38
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 occur
which elements are allowed under each heading
the order and frequency with which elements should appear Clarke, R. J (2001) L909-05: 39
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: 40
Document Type Definition
Extract of an SGML Memo DTD
: : : :
Clarke, R. J (2001) L909-05: 41
SGML Processing Systems
(1)
read a document instance, and refers to a DTD to find out how to process it
aspects 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: 42
SGML Processing Systems
(2)
SGML Data SGML Parser SGML DTD SGML Processing System Application Library Application Output
Clarke, R. J (2001) L909-05: 43
SGML Processing Systems
(3)
New Data New Data Legacy Documents Tag Application SGML Applications Non-SGML Editing System SGML Edit/Convert Graphics Files Bitmap Edit/Convert SGML Files
Clarke, R. J (2001) L909-05: 44
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: 45
SGML Example
Clarke, R. J (2001) L909-05: 46
SGML Example
Informational 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: 47
Information Markup
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
(Source: Nicholson Brothers Motorcycles Ltd. 1994) Clarke, R. J (2001) L909-05: 48
Information Markup (continued)
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 the degree wheel reads at KEYVALUE [UNITS=”DEGREES”] 37-38 /KEYVALUE before TDC. /PARA /STEP STEP [ ] PARA With a piece of wood, block the automatic advance in the fully advanced position. /PARA /STEP STEP [ ] PARA Using a TOOL hex key, /TOOL revolve magneto via the breaker point assembly until points just commence to separate. /PARA /STEP STEP [ ] PARA Fix the gear to magneto shaft, by placing TOOL box wrench /TOOL over nut and giving sharp rap with TOOL hammer. /TOOL /PARA /STEP /METHOD /TIMING /CHAPTER
(Source: Nicholson Brothers Motorcycles Ltd. 1994) Clarke, R. J (2001) L909-05: 49
SGML Benefits
Clarke, R. J (2001) L909-05: 50
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 types
enforces 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: 51
SGML Benefits
Data Management
common data repository for the enterprise
standardised formatting for information
minimise data duplication
control/check data quality
maximises the benefit of data entry and authoring Clarke, R. J (2001) L909-05: 52
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: 53
SGML Benefits
facilitiates data exchange between an organisation and business partners (Extranets; EDI)
promotes participation between partners
reduces costs, improves performance
streamlines operations and maangement practices, reduces ‘bottlenecks’ Clarke, R. J (2001) L909-05: 54
SGML Benefits
Video Case Studies about EDI
Note 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 Clarke, R. J (2001) L909-05: 55
Adopting SGML
Clarke, R. J (2001) L909-05: 56
Adopting SGML
Data Analysis
Feasilbility Study
Standardising Data Concepts
Data Entry & Document Conversion
Delivery of Data to Users Clarke, R. J (2001) L909-05: 57