1 / 16

Information Systems Design 3

Information Systems Design 3. Term 2. Topics. Classification and taxonomy in the news Problem-centred approach Term 2 topics Visualization with Graphviz. Taxonomy in the news - Spam. ITS now use SpamAssassin for email filtering

ros
Télécharger la présentation

Information Systems Design 3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Information Systems Design 3 Term 2

  2. Topics • Classification and taxonomy in the news • Problem-centred approach • Term 2 topics • Visualization with Graphviz

  3. Taxonomy in the news - Spam • ITS now use SpamAssassin for email filtering • False positives (classifying a good message as Spam) is much worse than False Negatives (spam getting through) • Multiple rules for classification: • ‘fuzzy logic’ : rules are assigned scores, based on accuracy, combined to produce an overall score for each message – if over a user-defined threshold, the mail is judged to be spam. • Default setting – 9% FNs, 0.6% FPs • http://eu.spamassassin.org/index.html

  4. Taxonomy in the news - Cannabis • From Thurs 29th Jan. Cannabis is to be reclassified from Class B ( with amphetamines and barbiturates) to a class C drug (with tranquillizers) • Classification determines maximum penalties for possession and supply • Classification also carries implied meanings about enforcement, social acceptability and safety. • New classification of penalties – under 18 and over 18 • http://www.timesonline.co.uk/article/0,,8122-974552,00.html

  5. A portal for CEMS • Member of group investigating an intranet for CEMS • ??

  6. One System - Many systems • Multiple system boundaries: • Technical systems • The pages, the server software, the DB • The site in the context of the web of links, search engines • Social systems • The site in the context of the owner’s business • The site in the context of the customer’s activity • Ecological systems • Site, and the business evolving to find its own, viable niche within the evolving business/community world

  7. Tutorial work • Ongoing case study • A web portal for CEMS students and staff • Discussing readings and the questions you might be asked in a exam about the reading. • Techniques applied to case study • Scenarios and use cases • Data quality evaluation • Data modelling • Visualisation

  8. Readings • Christopher Alexander ‘Goodness of Fit’ from Notes on the synthesis of Form • Christopher Alexander – excepts from ‘A Pattern Language’ • Eleanor Wynn – ‘Taking Practice Seriously’ from Design at Work: Cooperative design of Computer Systems ed Joan Greenbaum and Morten Kyng • Donald Norman – The Mackintosh Power Switch – Bringing Design to Software • … • Martin Fowler ‘Accountability Patterns’ from Analysis Patterns : reusable Object Models • Michael Jackson – ‘Problem Frames’

  9. Term 2 topics • What is the scope of ISD? • An IS as a socially embedded system • User-centred design • Data quality • An IS as a formal technical system • formal models • recurrent data patterns • Closing the gap • Viewpoints, frames • Scenarios and use cases • Business process modelling • IS as an evolving system • Usage analysis • Learning systems • Reflection • ISD as social practice

  10. CEMS Portal - 1 • How to start? • Which system boundary(s) to start with? • What development approach would be suitable?

  11. CEMS Portal - 2 • EXERCISE NOW: • Who are the stakeholders?

  12. CEMS Portal - 3 • What classification/taxonomy underpins your answer? • What is being classified – people, roles? • Which groupings make sense? On what basis?

  13. The current system • One way of describing the current system is to model the site as pages and links between pages: a map of the site. • We can draw the map by hand or • We can use a package called ‘Graphviz’

  14. Visualisation with Graphviz • Package of programs from AT&T • Lays out a directed or undirected graph from a textual description • DOT – directed graphs • NEATO – undirected graphs • Many uses in design • Site map • ER model from text

  15. Undirected Graph graph ebis { top [shape=triangle]; top -- drugs; top -- housing; top -- finance; top -- travel; top -- education; top -- health; drugs -- aids; drugs -- heroin; drugs -- cannabis; health -- aids; } Unix command: /pub_domain/GraphViz/bin/neato -Tjgp < ebis.txt > ebis.jpg

  16. Directed graph digraph perdika { index [URL="http://www.perdika.co.uk"]; index -> spec; index -> details; index -> story; spec -> index [style=dotted]; spec -> details; spec -> story….. /pub_domain/GraphViz/bin/dot -Tgif < perdika.dot > perdika.gif

More Related