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Introduction to ESTA

ESTA logo

 

 

 

PDC's expert system shell, ESTA, is easy to use and a great stand-alone environment for constructing advisory and decision support systems. Building advanced knowledge bases with ESTA requires no previous programming experience and it is suitable for many problem domains.(ESTA is included with full source in Visual Prolog).

You can use ESTA to build advisory systems that ensure:

Accessibility of knowledge
Delegation of decision competence
Secure and homogeneous decision making
Preservation of valuable knowledge
Fast and easy information retrieval
Easy and cost efficient document maintenance
Relief for overworked employees

ESTA includes an interface to Visual Prolog, which means that you can go beyond the built in functionality - you can build your own extensions to ESTA or integrate ESTA into an existing Visual Prolog application. This will require some programming experience.

In addition to advisory systems, ESTA is a great prototyping tool. A knowledge base in ESTA has a hierarchical structure from which a tree display is automatically drawn. You can edit or expand your knowledge base directly from the tree. This way you can easily get an overview of your knowledge.

And, you can easily interface ESTA to 3rd-party applications like spreadsheets, databases, word processors etc. via the built-in DDE-interface. ESTA includes an interface to Visual Prolog, which means that you can go beyond the built in functionality - you can build your own extensions to ESTA or integrate ESTA into an existing Visual Prolog application. In addition to advisory systems, ESTA is a great prototyping tool. A knowledge base in ESTA has a hierarchical structure from which a tree display is automatically drawn. You can edit or expand your knowledge base directly from the tree. In this way you can easily get an overview of your knowledge.

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The Dialog

ESTA is designed so that a dialog with an expert system running under the shell resembles having a chat with an actual expert in the subject area. The user initially provides some information - in the form of replies to questions posed by the system- and then he receives the appropriate advice. A record of the dialog can be logged in a window and it can be stored in a file for later reference.

For some questions, the user responds by selecting from a menu (e.g. "What is the problem with your car") in other cases, the user can click with the mouse on some part of a picture (e.g. "Point on the place where the noise comes from") and in some cases it is necessary to type in the answer (e.g. "What is your name"). If requested by the user, the system will elaborate on questions not readily understood, as well as provide a more general explanation of the course of the consultation and how conclusions have been reached.

ESTA is an easy-to-use expert system shell and a programming tool designed especially for constructing advisory and decision support systems. Through an easy-to-use Windows dialog, these systems provide the user with expert assistance in the shape of general advice and guidance. No previous programming experience is required to make advanced knowledge bases with ESTA.

It's fast and easy to make an expert system with ESTA

Easy to write rules
Intuitive, English-like syntax
Automatic design of a friendly, Windows user interface
Automatic syntax checking and reporting of errors

It is easy to structure your knowledge with ESTA to get a better overview of your problem.

ESTA automatically draws the structure of your knowledge base in an easy to navigate tree-display

Your ESTA license allows you to create and distribute complete advisory systems using a royalty-free runtime version of ESTA.

ESTA can be fully integrated with other Windows applications using DDE, or via an interface to PDC Prolog, C, Assembler and other programming languages.

Sample knowledge bases are included with ESTA

ESTA Features and Functionality

ESTA is available in a Windows version and a text mode DOS and OS/2 version. The knowledge bases can be converted between the Windows and text mode versions (except for the Windows specific functions) - thus it is possible to have the same knowledge base available for DOS, OS/2 and Windows users.

All language-specific parts of ESTA are stored in a special file that lets you make your own version of ESTA in any language with a minimum of effort.

ESTA includes provisions for generating royalty-free, consultation-only versions of the system, which may be distributed to end-users.

In addition to knowledge representation, ESTA includes useful features from traditional programming languages, such as procedure calls and mathematical functions.

ESTA is configurable - menus, startup-pictures, and other UI-functionality can be customized to match the needs of the specific application..

ESTA includes facilities for the knowledge base to call general purpose routines written in PDC Prolog and thereby also routines written in C, Assembler or other languages. You can even integrate ESTA into your own PDC Prolog, C or Assembler applications via the PDC Prolog interface.

ESTA provides the knowledge engineer with a number of views of the knowledge base, including a hierarchical tree-menu representation, where clicking on a node in the tree presents you with the corresponding rules.

The knowledge is automatically translated and syntax checked when you finish editing it, and errors are pointed out directly in the source code. Furthermore, ESTA has a validate command allowing you to check for type errors, circular references, undefined or unused knowledge elements.

ESTA also includes facilities to explain why a question is being asked or why an answer has been given, or to repeat advice given earlier in a consultation. In addition, advice can be given as a few simple sentences, large text files, graphic pictures, or even using Windows hypertext help files. ESTA also enables the user to suspend the dialog, change the answer to a previously asked question, or bring up new questions (which have not yet been asked) to answer.