Web Engineering An interim report for the Economic and Social - - PowerPoint PPT Presentation

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Aug 07, 2023 214 likes •334 views

News to discuss? Internet May Be Just A Fad, Says European Body (04-Dez-00) http://www.newsbytes.com/news/00/158904.html Web Engineering An interim report for the Economic and Social Research Council (ESRC), says that the development of the

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Prof. Dr. Dr. h.c. mult . Ge rhard Krüger , Albrecht Schmidt: Web Engineering, WS00/01 page 1

Web Engineering

Prof. Dr. Dr. h.c. mult. Gerhard Krüger, Albrecht Schmidt

Universität Karlsruhe Fakultät für Informatik Institut für Telematik Wintersemester 2000/2001

Prof. Dr. Dr. h.c. mult . Ge rhard Krüger , Albrecht Schmidt: Web Engineering, WS00/01 page 2

Web Engineering

Chapter 3: The Web – An Information System

Prof. Dr. Dr. h.c. mult . Ge rhard Krüger , Albrecht Schmidt: Web Engineering, WS00/01 page 3

News to discuss?

Internet May Be Just A Fad, Says European Body (04-Dez-00) http://www.newsbytes.com/news/00/158904.html An interim report for the Economic and Social Research Council (ESRC), says that the development of the Internet over the last decade may not be the epoch -making event that many have said.... ... The report stems from the results of a two-year investigation into the use of the Internet, undertaken by the University of Warwick, which claims that there is already some evidence that the Net may be a passing fad, as usage among British teenagers is already starting to fall from its previously high levels. The report speculates that as many as 2 million users of the Internet in the UK have stopped using it regularly because of the vast amounts of data online and the need to spend time on the Web to research that information....

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1. Introduction and History
2. Media and Information
3. Organizing Information
4. Access to Information and Navigation

Methods for Information Access Hypertext Navigation Access Strategies for the Web

5. Describing and coding Information

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Methods for Information Access

addressing pages directly search/browse in catalogs search for keywords associative navigation

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Addressing Pages Directly

requires unique addresses URL: Uniform Resource Locator how to get the address? external channel, e.g. TV, radio, press, print, email, etc. guessing the DNS-name, e.g. www.uni-karlsruhe.de, www.oracle.com, www.linux.org conventions E.g. index.html, default.htm, robots.txt

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Quality of Search Results

recall = the ratio of documents retrieved versus the

number of available documents relevant to the query, i.e., the fraction returned out of all desirable documents

precision = the ratio of the number of relevant

documents retrieved versus the total number of documents retrieved, or the useful fraction of what was actually retrieved

see information retrieval

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Search / Browse in Catalogs

browse predefined classes search if classes/subclasses are unknown less directed, open search strategy if you can not specify what you are looking for ... How to get listed in a catalog? automatically (submit in a certain category) pages are manually selected, reviews, and added address of the catalog must be known examples yahoo.com web.de lycos.de netcenter.com dmoz.org open directory project

and many others ...

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Search for Keywords

specific WWW server parts of a search engine

robot/crawler indexer analyzer module database retrieval component

recommendation system

ther user rank content

number of links to a page how often is the page

pened when displayed

etc ...

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Search using a Query Language

mechanisms to search for keywords keyword matching query language

Boolean operators “fuzzy operators” e.g. NEAR search for values of certain attributes examples: www.altavista.com

+domain:com +Netscape +host:www.ibm.com +confidential +image:sharon * +title:stone +url:Java +applet:* link:www.teco .uni-karlsruhe.de (image:bill NEAR clinton ) OR (image:clinton NEAR bill) OR title:"Bill Clinton"

Prof. Dr. Dr. h.c. mult . GerhardKrüger, Albrecht Schmidt: Web Engineering, WS00/01 page 11

Incremental Search

refine search results search within results concept map categorizing results

source: www.altavista.com www.northernlight.com

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Advanced Search Concepts I

specify search by search term term exclusion date top level domain domain hostname language country matching (exact, fuzzy) search term in:

title body domain link

source: www.google.com

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Advanced Search Concepts II

searching for similar pages searching for pages that link to a page searching within a certain domain

specialized search engines

source: www.google.com

cached pages – no 404

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Natural Language Search

query a search engine in „plain“ English

source: www.askjeeves.com

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Multimedia Search

content images video audio based on

text/keywords next to content

e.g. www.altavista.com www.ditto.com music.lycos.com multimedia.lycos.com

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Associative

semantic links in hypertext links in text (related content) icons and images maps different types of links different semantics

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Search Functionality

providing a search function to visitors of a specific site

(company web site, university site)

when a users is on the site you want to help him to find

what he/she is looking for

two approaches search engine or directory for the specific site

customized interface detailed inclusion

and exclusion rules

using a „public“ search engine with attributes to restrict the search to this site

embedded in

the site

also useful instead

f a missing page

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Hypertext - Navigation

links beyond content and semantic navigational structure within the content up, down, next, ...

ften based on icon

author builds/defines this structure tools for navigation history, back/forward, home bookmarks in the user interface of the web client navigational patterns

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Hypertext – Navigational Patterns

Navigational Design Patterns [Rossi et al. 98]

text based

e.g. www.useit.com

landmark

„Provide direct access to critical sub-systems in the Web Information System“

set-based navigation

„Organize the information in Sets of related information items. Provide intra-set navigation capabilities.“

ften combined landmark & set-based navigation

e.g.: www.sun.com e.g.: www.amazon.de

metaphorical navigation

z.B.: www.iflyswa .com, www.hagebau.de

http://www8.org/w8-papers/5b-hypertext-media/improving/improving.html

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Text Based Navigation

Source: http://www.useit.com

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Landmark & Set-based Navigation I

Source: http://www.amazon.de

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Landmark & Set-based Navigation II

Source: http://www.wapforum .org

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Metaphorical Navigation I

Source, 1998: http://www.iflyswa.com

Prof. Dr. Dr. h.c. mult . GerhardKrüger, Albrecht Schmidt: Web Engineering, WS00/01 page 24

Metaphorical Navigation II

Source: http://www.hagebau.de

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1. Introduction and History
2. Media and Information
3. Organizing Information
4. Access to Information and Navigation
5. Describing and coding Information

Markup SGML XML HTML

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Coding Documents

GIF89a`P÷ •àc ˆ„ +0 ÿ1))scÿ”{„Üo%4$1Üoa*~1 ÖÎÿÞçççï÷ï÷÷ÿ~8¾•þ`ˆ-

íŸ£ÚÏ#³ó•àc ˆ„¯)zˆR

QÄV„Ä&˜!,ÖY¹BCÛ ßr³j fÜQ¢ùÌ4Ífƒ?sÔCÞ¹Ã/jò†þ „Ä&˜!,ÖY¹BCÛ ß„Ä&˜!, ÖY¹BCÛ ßÜQ¢ùÌ4ÜQ¢ùÌ4 {\listname ;}\listid3} {\list\listtemplateid0\ {\leveltext\'01-;} {\levelnumbers;}\f0 \chbrdr\brdrnone\brdrcf1 \chshdng0\chcfpat1\chcbpa \fbias0 \fi-360\li360 %%EndSetup %%Page: 1 1 1 0 bop 1007 872 a Fl(Location\255Based) 32 b(Personal)i(Agents) 820 y Fk(\003)781 1112 y Fj(Seng)5 b(W)-8 b(ai)25 b(Lok)o(e)1392 1076 y Fi(y)1427 1112 y Fj(,)g(Andry)f(Rak)o(otonirain)o(y)2325 1076 y Fi(yy)2391 1112 y Fj(,)g(Karsten)h(Schulz)3046 <td><font face="Arial, Helvetica"> <P> In 1995/1996 I did an MSc in computing at the <A HREF="http://www.mmu.ac.uk">Manchester Metropolitan University</A> in the <A HREF="http://www.doc.mmu.ac.uk"> Department of Computing</A>. Studying in <A REF="http://www.manchester.com/"> \twocolumn[ \begin{center}\Large { A Modular Neural Network Architecture with Additional Generalization Abilities for High Dimensional Input Vectors} \end{center}

RTF HTML PS tex GIF

Prof. Dr. Dr. h.c. mult . GerhardKrüger, Albrecht Schmidt: Web Engineering, WS00/01 page 27

Markup

roots: computerized typesetting

typesetting macros embedded in ASCII

layout

directives, e.g. TEX

presentational markup

commands

to define the layout

semantic markup

authors put annotations into their texts to help the publisher to

understand what type of text this is (e.g. „this is a heading“)

annotations are agreed between author and publisher
publisher decides on the layout
descriptive markup

describing

content not the layout

markup to support search in documents

words

in headings are more important than in footnotes

markup for machines vs. markup for humans

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Markup - ISO-Definitions

markup text that is added to the data of a document in order to convey information about it descriptive markup markup that describes the structure and other attributes of a document in a non-system-specific way, independently of any processing that may be performed on it processing instruction (PI) markup consisting of system-specific data that controls how a document is to be processed

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