Frequently Asked Questions
is a knowledge base?
is a knowledge base different from a database?
use a knowledge base?
is a fact?
is a subject?
is a term?
is a predicate?
is a complement?
is a hierarchy?
is multiple inheritance?
are superconcepts, subconcepts and sibling concepts?
might want to use Fact Guru?
can you put in a Fact Guru knowledge base?
do I create a knowledge base?
long does it take to create a knowledge base?
would I want to spend the time creating a knowledge base?
it better to create my own knowledge base or hire someone to do
What is knowledge?
Knowledge is information
that people use to reason about the world and make decisions. Knowledge
is stored in people's heads as well as in books, on web sites etc.
What is a knowledge base?
A knowledge base (often
abbreviated kb) is a place to store knowledge about a topic
in an concise, organized manner. It presents facts that you might
otherwise find in a book, or in a collection of books or web sites.
Understanding a topic is easier when you look at a knowledge base
than when you read a book because only the essential information
is in the knowledge base.
How is a knowledge base different from a database?
A database contains details
about sets of particular things - for example it might contain lists
of people, lists of companies, and lists of products. A knowledge
base, on the other hand, primarily describes what is known about
certain types of things in general. So, for example, it would say
that people have parents, a birthplace, etc., but would normally
not describe a large number of particular people. A knowledge base
can, therefore, be used to describe the structure of a database
(sometimes this is called the schema or the metadata). A knowledge
base can do far more than that, however - it can describe all that
is known and the relationships among a large number of different
Why use a knowledge base?
A knowledge base can
save you time and money by acting as a repository of facts you would
otherwise have to search for each time you needed them. Looking
facts up in a knowledge base is fast and easy compared to finding
them in a book, or searching on the web. For some examples of uses
for knowledge bases see Uses for Knowledge
What is a fact?
A fact is one piece of
information about a subject. For example: "bicycle has two
wheels" or "part number 2341 costs $2.95". It is
expressed in simple and clear language that is easy to understand.
(This simplicity also makes it easy to translate into other languages
using automatic translation software).
What is a subject?
A subject is the thing
that the fact is about. In Fact Guru, all the facts about one subject
appear grouped together for easy reference. You may also see the
word 'concept' used as a synonym for subject.
What is a term?
A term is one or more
words that, when used together, identify a subject. A term is normally
a single noun (like 'computer'), several nouns strung together (such
as 'computer display') or noun(s) qualified by adjective(s) (for
example. 'large computer display'). Several terms may identify the
same subject, in which case they are called synonyms (such as 'computer
display' and 'computer screen').
What is a predicate?
The predicate is the
part of a fact that consists of a verb. For instance, in the fact
"dog eats meat" the predicate is "eats". In
the basic Fact Guru display, you will not see the predicate separated
from the rest of the fact. You will need to be aware of predicates
only if you are creating a knowledge base.
What is a complement?
The complement is the
part of a fact that give the value of the predicate. For example,
in the fact "dog eats meat" the complement is "meat".
In the basic Fact Guru display, you will not see the complement
separated from the rest of the fact. You will need to be aware of
complements only if you are creating a knowledge base.
What is a hierarchy?
A hierarchy is a way
of arranging subjects to show the relationships between them. For
example, a family tree is a hierarchy where the subjects (people)
are arranged so that every subject is a child of the subject above
it in the tree. The relationship shown in a family tree is "is
a child of".
Fact Guru arranges subjects
in several types of hierarchies. The first is what is called an
"kind of" hierarchy. In this type of hierarchy, the relationship
is "is a kind of". Imagine a hierarchy of cars where subject
is a kind of the subject above it. So you would see "car"
with "sports car" below it and "Ferrari" below
that. You can read this as "A sports car is a kind of car"
and "A Ferrari is a kind of sports car".
A hierarchy in Fact Guru
is written as an indented list with more general subjects indented
less than more specialized subjects. So the car hierarchy could
look something like this:
- sports car
- station wagon
- luxury car
In Fact Guru the same
hierarchy can also be viewed as a graph. The tree has been turned
on its side so the most general subject is on the left.
Fact Guru can also arrange
subjects in a topic hierarchy. This is similar to the table of contents
in a book where subjects are grouped under similar topics. For example,
here is part of a topic hierarchy about cars:
- Buying a car
- New cars
- Used cars
- How to get a safety
- Maintaining your car
- Regular maintenance
- How to wash your
What is inheritance?
In the general sense
of the word, you inherit things from your parents: your genes
for eye and hair colour and perhaps property or money.
In Fact Guru subjects
inherit things from their "parents" too. In the car kind
of hierarchy, think of "car" as the parent and "sports
car", "station wagon" and "luxury car"
as its children. If car has a fact associated with it, such as "car
has 4 wheels", then its children will inherit this fact. So
sports cars, station wagons and luxury cars all have 4 wheels. The
beauty of inheritance is that you only have to write the fact once
- for the most general subject that it applies to - and all its
descendants will inherit this fact. So Ferraris and Cadillacs also
contain the fact that they have 4 wheels.
What is multiple inheritance?
In real life, you inherit
things from both your parents. You might inherit a talent for music
from your father and a love of art from your mother. In Fact Guru,
subjects can have more than one parent too. Actually, they can have
as many as needed.
Here's an example in
a hierarchy about animals. A cat is an carnivore but it is also
a pet. So its two parents are "carnivore" and "pet".
From carnivore, cat could inherit the fact that it eats meat and
from pet it could inherit the fact that it has an owner.
What are superconcepts, subconcepts and sibling concepts?
'Concept' is another
word for subject. A superconcept is a parent of a subject, if you
think of a hierarchy as a kind of family tree. A subconcept is a
child of a subject and a sibling concept is a subject's brother
In the example hierarchy
below, "car" is the superconcept of "sports car",
"station wagon" and "luxury car". Going the
other way, "sports car", "station wagon" and
"luxury car" are all subconcepts of "car" and
they are also all sibling concepts of each other.
Who might want to use Fact Guru?
Fact Guru can be used
by teachers, students, designers, writers and anyone else who needs
to organize, understand and display knowledge. For some examples
of uses for knowledge bases see Uses for
What kind of information can you put in a Fact Guru knowledge base?
A Fact Guru knowledge
base can store text, pictures, video, sounds, or links to web sites.
So you could create a knowledge base about your company's products,
your favourite music, scientific data, or references for a course.
In the past, people using our tools have built knowledge bases about
optical disk technology, the Java programming language, and French/English
terminology, among others. And yes, you can use it to store your
How do I create a knowledge base?
Creating a knowledge
base consists of finding information sources, defining the subjects,
arranging the subjects in a hierarchy, adding facts, and checking
the knowledge base. For a more detailed look at how this is done,
look at How to create a knowledge base.
How long does it take to create a knowledge base?
We have found that an
experienced knowledge engineer can create a knowledge base from
a good source of knowledge (such as a book) at a rate of about 20
facts an hour. This rate depends on the quality and type of the
source of knowledge. If the knowledge engineer has to obtain the
facts by interviewing other people it will obviously take longer
to build a knowledge base than if the facts are already collected
in some form. If the knowledge engineer has to deal with multiple,
conflicting sources of facts, time will also be spent verifying
and consolidating the knowledge.
Why would I want to spend the time creating a knowledge base?
Once a knowledge base
is built, it will save you time in the long run. All the work of
gathering the facts into one place and verifying them has already
been done. It's like having a proper filing system for your business
documents instead of keeping post-it notes stuck all over your desk.
Is it better to create my own knowledge base or hire someone to
It depends on your situation.
If you already have the facts collected in a document, web site
or catalogue, then it may be faster and more cost-efficient to hire
our knowledge engineers to create the knowledge base. They are experienced
in knowledge base development and can work rapidly and accurately.
If you are creating a
knowledge base at the same time as developing an idea or a product,
it may help you to build the knowledge base yourself. Building a
knowledge base helps organize your ideas, clarifies the relationships
between subjects and forces you to standardize your terminology.
In fact, building a knowledge base is a good design exercise, whether
you are planning to build a software system, write a book, or teach