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The Istar Knowledge Server

You may connect to the demo Istar Knowledge Server sites via any of the following hyperlinks:
  1. click here for main site (Amiga 12000 030 18Mb)
  2. click here for older Amiga 4000 040 6Mb,
  3. click here for an old Amiga 2000 030 5Mb.
(The Amiga 4000 seems to freeze up a lot, possibly overheating?)

Click here for main Istar home page.


What is the Istar Knowledge Server?

Istar is a knowledge based system which will give you advice about a variety of topics. Which topic it gives you advice about depends on which knowledge base it is using at the time. The knowledge base is like a CD while Istar is like the CD player: just as you can select from a number of CDs to load onto the player, so you can select a number of knowledge bases to load into Istar.

Knowledge bases come in many types and sizes, but the ones Istar runs are designed to give you advice about some expert subject. You are asked perhaps two dozen questions and then some results are given, with some explanation. A knowledge based system possesses some apparent intelligence, in that it will normally only ask you questions that are relevant and suppress irrelevant ones, and as you answer each question the information you give is acted upon immediately, so that it might steer the course of questions into a different track, or even stop it altogether.

A number of knowledge based systems exist in offices and laboratories all over the world, but Istar has a difference: it can be attached to the internet so that it can be operated from anywhere in the world. (It can also be run locally on a machine on your desk if you wish.) The main internet-accessible copy of Istar is currently running at the Information Systems Institute at the University of Salford, UK, and offers the current demonstration knowledge bases (which are based on real ones developed at the University):

Others will be added from time to time.

How Does Istar Work?

When you connect to Istar it will give you a Welcome Page that lists the knowledge bases currently available together with a brief description of them. You select the one you want, and Istar loads a copy for you and starts what is known as an inference session. An inference session is a sequence of questions and answers, during which time Istar tries to satisfy a 'goal' (or a list of goals). It does this by working back through an inference net, of evidence that contributes to belief in the goal.

For instance, to advise you whether to buy shares in a given company (the goal), Istar needs to find out whether profits are likely to rise, whether the company is growing, whether the company is well managed, etc. To find out whether the profits are likely to rise, it needs to find out what the recent financial history has been like, whether there has been good capital investment, etc. To find out whether there has been good capital investment it asks you, the user. You can give a degree of belief rather than a strict yes/no answer, if you do not have full information.

When it finds some piece of information that cannot be derived from others it sends it to you as a question on a specially formatted question page. You select the appropriate answer, and Istar processes that to seek the next appropriate question. On the question page there are a number of other options, besides selecting an answer, such as obtain help and explanation of the question, pausing the session, viewing statistics or setting a timeout limit.

(Normally the timeout limit is ten minutes, so that if you do not answer within ten minutes then Istar will stop and abandon your inference session. But you can set the timeout to anything up to an hour if you know you need to obtain information to a question. For instance, you might wish to browse the web to find out information about the company you are thinking of buying shares in.)

After a number of questions, Istar has enough information to come to some belief about the goal; in this example, a degree of belief about whether it is advisable to buy shares in this company.

Then it offers you a What Now Page, from which you have various options, such as viewing the goals, receiving a document that Istar has generated (currently only used for the Contracts knowledge base), resuming a paused session, restarting afresh, viewing statistics, returning to the welcome page or stopping altogether.

How to Drive Istar

Driving Istar is mainly a matter of selecting answers to questions put to you on a question page. But some pages have several questions on them, as an HTML form: a form page: you select the answers then hit the Go button.

At any time you can go back to a previous question (using your browser's window history) and give a different answer. In this way, it is OK to change your mind.

To alter the timeout, just click on the timeout you need; Istar shows you what the current timeout setting is at the bottom of the page.

What to Expect

When you connect to the Istar Knowledge Server from a link like the above, expect the following pages:

For more details of what to expect, and an understanding of how the server works, go to How It Works.

When Things Go Wrong

This section under construction. If you find a fault or a puzzling thing then please email me and it will be added to this section.

Things sometimes go wrong. Istar is still only a beta program, and still under development. Here is a list of problems you might meet.

Creating Your Own Knowledge Base

If you like the concept of the Istar knowledge server, and would like to make some of your own knowledge available in this fashion, then email me. There are several options available:

For details of how to go about creating your own KB once you have Istar, click here.

Technical Information

See general documentation or explanation of how server works.

Examples of Pages

These pages are only samples, and the exact wording might change from time to time.

Welcome Page

Welcome. You are connected to the Istar Knowledge Server.

It allows you to run knowledge bases over the internet using your browser. You will then be asked a sequence of questions by to which you must give a reply, and then a result will be given.

Please select the knowledge base you wish to start, from the following list, and you will be presented with the first question of the sequence. It may take a few seconds, during which time the KB of your choice is being loaded, reset and a search is made for the first question.

Disclaimer: All the KBs, and the knowledge contained within them, is used at your own risk, and WARNING: most of them are still in development.

Details of Knowledge Bases

Write your own Contract

This sizeable KB will write a draft contract for a construction project. It will ask you between 20 and 60 questions about the construction project and, from the information given, will select clauses for a contract. It then orders them intelligently, compiles a contract and displays it for you. You can then save it and edit it as you wish. Also you can alter some of the parameters of the project and see what differences emerge in the final contract. This is a demonstration version, yet it can often yield useful or at least interesting and stimulating results.
This KB emerged from the INCA project, motivated by a concern that standard forms of contract are often not suited to the real needs of the participants, and are often amended inconsistently and lead to adversarial relationships. This KB is different: embodying principles of agreement and compiling contracts intelligently from standard components. It is designed to be used by both parties working together, discussing the questions asked. The contracts produced should thus express more fully the real agreed desires of the parties.

Tree Species Selection

Suppose you wished to plant a wood or group of trees on some land you own; what trees should you plant? Normally, it will be a mixture. This KB advises you what characteristics of tree species are important when deciding your mix. It asks around two dozen questions and has about a dozen goal attributes.
This KB emerged from the GIS/KBS project, in response to an initiative from the UK government to encourage landowners etc. to plant more trees. There is concern that Britain's tree cover is less than 4%.

Internet Trust

Can I trust a message I have received? In critical cases, you would only trust the authenticity of the sender of a message when the sender was a subscriber to a Certification Authority with a good Certification Practice Statement (CPS). This KB asks you for information about the CPS and determines whether there are reasons for not trusting the authenticity of the message sender. Its main goal is 'Can't Trust', and the more asterisks the worse it is. With most CPSs it's pretty bad, so look at the sub-goals to see which of them is bad, and then use your judgement on whether or not to trust the message. Note: this KB deals only with authenticity of the sender, not whether they are authorised to do what they say in the message. This KB - a draft version - could be useful in two ways: This KB emerged from the EPSRC-funded project Intelligent Computation of Trust 1997-2001, as an outcome of the first stage. The second stage of the research is to see how appropriate it would be to obtain a lot of the information automatically.

Shares Advisor

Should I buy shares in a company? This KB - purely a demonstration version and not to be taken seriously - uses bayesian accumulation of evidence to determine how advisable it would be to buy shares in a particular company. It asks questions about the company, its management and the market it is in, and produces a visual indication in the goal display of how advisable it would be to purchase shares. It also shows the belief in some of the sub-goals that contribute to the goal so you can see why it thinks the way it does.
This KB was produced by one of the students on the Master of Information Technology course at the University of Salford, whose husband worked in selling shares.

Test KB

Click here to cancel.

Page created by Istar knowledge server.

KB Introduction Page

This can take any form, and depends on what has been written for the KB. It has three hyperlinks at the bottom: to start the inference, to stop or to return to the welcome page. It also allows you to set the TimeOut Period.

Question Page

Do you believe the company has been making good capital investments recently ?

Please indicate your degree of agreement:

-5, -4, (disagree) -3, -2, -1, 0, 1, 2, 3, (agree) 4, 5,


HELP. PAUSE (can resume). Stats.

Timeout set at 10 minutes; Set to 1 5 10 20 30 60 minutes.

Please click on one of the above choices in answer to your question. You will then be taken to the next page.

Page created by Istar knowledge server.

Form Page

This page contains several questions in a form.

What are the company's recent financial indicators?

Profits have been healthy over recent years Help.
Recent Dividend has been healthy Help.
Price earnings less than average Help.
Share Yield is below average in this company Help.
The comapny's Dividend cover > average Help.

PAUSE (can resume) Stats.

Timeout set at 10 minutes; Set to 1 5 10 20 30 60 minutes.

Please click on one of the above choices in answer to your question. You will then be taken to the next page.

Page created by Istar knowledge server.

'What Now' Page

The inference session has stopped, and results are available. What would you like now:

Timeout set at 10 minutes; Set to 1 5 10 20 30 60 minutes.

Page created by Istar knowledge server.

Goal Results Page

On this page the values of the goals are in a table, values on the right. A line of asterisks shows a degree or proportion or probability between 0..1. Other values you might encounter are numbers, boolean YES/NO etc. If you click on the names of goals then you will be shown their antecedents in a similar manner, but the table has a middle column (from version 1.11) that shows the direction of effect of antecedent value:

The Goals are:

Important that all trees are tolerant of general exposure |******..|
Important that all trees are generally hardy |******..|
Important that all trees are important to air pollution |****....|
Important that all trees are tolerant of salt spray, or salt in atmosphere |***.....|
Important that trees not susceptible to squirrel damage |*****...|
Important to have trees that are suitable as nurse species |**......|
Important that all trees can stand waterlogging or flooding |*.......|
Important that all trees are tolerant of excessive drying |**......|
Important that all trees are frost hardy |**......|
Important that trees can cope with low Nitrogen |**......|
Importance of ability to thrive on site's soil |****....|
Important that all trees selected are native species |****....|
Associated bird species mix is particularly important |******..|
Associated insect species must be carefully considered |*****...|
Important to have good mixture of tree species |*****...|
Important that taller species allow light penetration |****....|
Important that trees suitable for coppicing |****....|
Important to have species suitable as 'standards' |**......|
Important to have berry bearing species |**......|
Important to include species that provide low cover |***.....|
Important to include species with attractive autumn foliage |****....|

Timeout set at 10 minutes; Set to 1 5 10 20 30 60 minutes.

See KB Intro Page again.
Resume interrupted session. Restart session from beginning.
Return to welcome page. Stop entirely.

Page created by Istar knowledge server.

Here is an antecedent page:


Associated insect species must be carefully considered

has value: |*****...|

Its antecedents are:

|***.....| |*******.|
Need natural food to be available +
Need high diversity of plants and animals +

Click here to reset it and resume.

Timeout set at 10 minutes; Set to 1 5 10 20 30 60 minutes.

See KB Intro Page again.
Resume interrupted session. Restart session from beginning.
Return to welcome page. Stop entirely.

Page created by Istar knowledge server.

Copyright (c) Andrew Basden 1999.

Last updated: 11 September 1999 added what to expect etc. 21 September 1999 Added contents and email for comments. 25 October 1999 added new goals results page comments. 12 May 2000 new server demo links. 7 July 2000.