Frequently Asked Questions
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. 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. 3. 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 interrelated things. 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 Bases. 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). 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. 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'). 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. 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. 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:
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:
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. 12. 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. 13. 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 or sister. 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.
14. 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 Knowledge Bases. 15. 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 family tree. 16. 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. 17. 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. 18. 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. 19. Is it better to create my own knowledge base or hire someone to do it? 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 a course. © Fact Guru, 2001 |
