Systemic Semiotic Design Practice:

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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