"Helps you Think."
The Istar Knowledge Server
You may click here to
connect to the demo Istar Knowledge Server site.
A selection of demonstration knowledge bases is available for you to try out, of various types and roles.
Click here for main Istar home page.
Contents:
Istar is a knowledge based system which will give you advice about a variety of topics based on expert knowledge. This can help you think about the topic, because Istar allows you to explore the knowledge and undertake 'what-if' scenarios - which is useful in ill-structured domains of knowledge like share dealing, tree species selection or authoring of construction contracts (all of which are available on the server demonstration site).
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. Except, as just explained, you cannot change the music on your CD while in Istar you can try out different things.
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):
- Write your own contract for a construction job
- I'm thinking of buying shares: is this a good company to invest in?
- I'm thinking of planting some trees; how should I select them?
- Can I trust the authenticity of internet messages handled by a given Certification Authority?
Others will be added from time to time.
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.
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.
When you connect to the Istar Knowledge Server from a link like the above, expect the following pages:
- The Welcome Page. This presents you with a list of knowledge bases offered by the server. Normally it has a brief list at the start of the page and longer details of each KB further down. (Sometimes, that is from some hyperlinks designed to give you direct access to a particular KB, you skip the welcome page.) Click on the name or label of the KB you wish (either from the brief description or from its heading in the longer desription and you proceed to ...
- The KB Introduction Page. (Sometimes this page is missing, so inference starts immediately.) This page provides an introduction to the KB, such as telling you what type of questions to expect, how accurate its results are, etc. Whatever the creator of the KB decides to give you. Click the 'start inference' hyperlink to start the inference session, and you will receive a sequence of ...
- Question Pages. These pages are presented in a sequence, each containing a question and a means of answering it. Often, the means of answering it is to click on a hyperlink for the answer of your choice. Sometimes, though, you will be asked to enter a value (such as a number or a string) and then hit the 'OK' or 'Go' button. Often (depending on whether the KB believes it makes sense) you have the option of entering 'Unknown' as a value; use this when you cannot give an answer. From these pages you can also pause the inference session, proceeding directly to the What-Now page, or obtain help. You can also set the TimeOut. Sometimes, however, in place of the normal question page, you will be presented instead with ...
- Questions Group Form Pages. This page is like the question page but has several questions grouped together. Enter a value for each and hit the 'OK' or 'Go' button. Over to the right hand side you have the option of obtaining help for each question individually.
- Help Pages. If you have hit a Help hyperlink associated with a question then you obtain help or explanation of it. This contains several types of Help (in early days simply labelled as Help 1, Help 2, etc.). The intention is that, for example, Help 2 explains concepts in the question, Help 3 explains what happens on certain types of answer, Help 4 gives references to other material, and so on - all depending on what the knowledge engineer decided to include. Don't be surprised if many helps are blank.
- The What-Now Page. This page is presented after all necessary questions have been asked and answered (end of session) and also when you hit the Pause hyperlink. It gives you a number of options: to see results, to obtain a document if any is created by the KB, to obtain statistics, to resume a paused session, to start a new session with the same KB, to return to the welcome page, or to stop.
- The Results Page. This gives you a table of results, which are the values that have been inferred for various goals in the inference session goal list. Rather crude, but it should be self-explanatory. You have the option of clicking on each of the goal names and obtaining a view of what contributed to each goal value.
- The Document. If none is available then you should get a message, or perhaps a blank page. But some KBs generate a document, for example, one KB writes a contract for you. The facility is crude at present.
For more details of what to expect, and an understanding of how the server works, go to How It Works.
This section under construction. If you find a fault or a puzzling thing then please email me, via "Istar @ basden . u-net . com", 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.
- PROBLEM: I selected a knowledge base, answered the first question, but got straight back to the welcome page. REASON: Istar occasionally times you out immediately you select a knowledge base; bug being looked at. REMEDY: Simply reselect the knowledge base.
- PROBLEM: I hit the answer to a question but was returned to the welcome page. REASON: Istar has timed you out because you took too long to answer the question. ACTION: Normally you have ten minutes to answer each question; but you may set this longer if you wish. Each question and results page offers a selection of timeouts; click one.
- (This seems to happen with my version of AWeb, 3.1, but not with Netscape nor IE.) PROBLEM: After the first question, only part of the page appears. REASON: Being investigated. A 'RST' signal is being sent half way through the message for some reason. ACTION: Use a different browser for the time being. Let me know, via "Istar @ basden . u-net . com", if you get this error, and tell me what browser you were using. Thanks.
- More to be added as they come in.
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, via "Istar @ basden . u-net . com",. There are several options available:
- If you have expertise in building knowledge based systems, then you could download Istar, learn to use it properly, and build your own. It's free (at the moment).
- If you haven't this expertise and would like to gain it, then we have a module of a Masters Course in which you can learn to use Istar, hands on. Then you could build your own.
- But, because Istar runs on an Amiga computer, and you do not wish to obtain one (even though they're very cheap these days), you could ask us, via "Istar @ basden . u-net . com", to build the knowledge base for you. We would have to charge reasonable consultancy rates for this exercise, but the more you do, the less we would charge you for.
- Where should your knowledge base be run? There is room for a few extra knowledge bases with particular characteristics on our machine at the moment.
- Alternatively, you could purchase your own dedicated machine. Depending on amount of usage expected, a relatively meagre computer might suffice, costing as little as $1000. Not bad, for making your knowledge available worldwide!
For details of how to go about creating your own KB once you have Istar, click here.
See general documentation or explanation of how server works.
These pages are only samples, and the exact wording might change from time to time.
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.
- Write your own Contract for a construction project. A large KB, this will ask you
between 20 and 60 questions about the construction project and
then assemble a draft contract for you.
More details below.
- Tree Species Selection Suppose you wished to plant a wood or group of trees on some land you own; what trees should you
plant?
More details below.
- Internet Trust Can I trust a message I have received? Check out the quality of the CPS
of a Certification Authority, to make your judgement about this.
More details below.
- Shares Advisor Should I buy shares in a company? Only a demo.
More details below.
- Test KB
More details below.
Details of Knowledge Bases
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.
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%.
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:
- To let you judge the authenticity of a message by checking the quality
of the sender's CA's CPS
- To help you design your own (internal?) CPS; it will show you many of
the factors that are important to trust in authenticity.
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.
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.
Click here to cancel.
Page created by Istar knowledge server.
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.
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,
Unknown
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.
This page contains several questions in a form.
What are the company's recent financial indicators?
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.
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.
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:
- + means that if the antecedent increases in value then so does your attribute
- - means that if the antecedent increases in value then that of your attribute decreases
- 0 means that the effect cannot be predicated, such as a CONTROL relationship or a randomizer.
The Goals are:
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:
Attribute:
Associated insect species must be carefully considered
has value: |*****...|
Its antecedents are:
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. Comments and queries are welcome, via "Istar @ basden . u-net . com".
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. 25 October 2000 about ill-structured knowledge. 7 February 2001. 17 December 2001 removed redundant servers. 25 February 2002 larger text for portal.