Deduction inference system for solving complex propositional logic problems in response to signals from a plurality of system sensors

• US 5,390,287 A
• Filed: 03/19/1992
• Issued: 02/14/1995
• Est. Priority Date: 04/26/1989
• Status: Expired due to Fees

• Current Assignee: Takashi Obata
• Original Assignee: Takashi Obata
• Inventors: Obata, Takashi
• Primary Examiner(s): Downs, Robert W.
• Application Number:
  US07/854,020
• Time in Patent Office: 1,062 Days
• Field of Search: 395/51, 395/67, 395/81, 395/904, 395/906
• US Class Current: 706/57
• CPC Class Codes: G05B 13/028 using expert systems only
• CPC Class Codes: G06N 5/046 Forward inferencing; Production systems
• CPC Class Codes: Y10S 706/904 Manufacturing or machine, e.g. agricultural machinery, machine tool
• CPC Class Codes: Y10S 706/906 Process plant

Abstract

A deduction inference system is connected to a plurality of sensor elements, a display device, and an actuator mechanism. The deduction inference system processes stimulus sensor signals received from responding sensor elements. Each sensor signal uniquely identifies condition/status information representative of the particular sensor element transmitting that signal. Using preestablished knowledge rules previously programmed into its memory, the deduction inference system is capable of executing and solving a "non NP-complete" deduction inference on the inputted stimulus sensor signals. The resulting data can then be presented onto a display device as a user friendly "smart" informational message or transmitted to an actuator mechanism attached thereto to control electro-mechanical devices and provide a real-time response to changing condition/status information transmitted form the plurality of sensor elements.

Claims

1. A deduction inference system coupled to a plurality of sensors for transmitting condition/status signals to said deduction inference system and to output means for receiving command signals from said deduction inference system, said deduction inference system comprising:

memory storage means for storing a plurality of predetermined propositional logic clauses, each propositional logic clause defining the conditions under which at least one of a plurality of flags will be set in response to transmitted condition/status signals from said plurality of sensors;

means for selecting appropriate propositional logic expressions from said memory means in response to said transmitted condition/status signals and storing them in a working memory;

transformation formulae logic means for transforming said set of propositional logic clauses into a set of derivative clauses logically equivalent to said set of propositional logic clauses;

deducing means for performing deductions on the basis of said set of derivative clauses and said transmitted condition/status signals, said deducing means comprising;

means for identifying a unit clause containing a single variable "p" within said set of derivative clauses and removing said unit clause from said set of derivative clauses, wherein said means for identifying a unit clause comprises means for selecting a dummy variable "p" from a compound clause in said set of derivative clauses when a unit clause cannot be identified;

means for identifying compound clauses containing multiple variables within said set of derivative clauses;

means for searching said compound clauses for the variable "not p";

means for deleting the variable "not p" from each of said compound clauses to form a new set of derivative clauses, wherein said identifying means, said searching means, and said deleting means are repeatedly accessed until no more unit clauses containing a single variable can be identified; and

means for generating a solution on the basis of said deductions; and

means for generating command signals to said output means based on the solution from said deducing means, said output means including an actuator mechanism which, in response to said command signals, induces a physical response by transmitting activation signals to restore the stability of at least one device whose operation is directly or indirectly monitored by said plurality of sensors.

2. A deduction inference system coupled to a plurality of sensors for transmitting condition/status signals to said deduction inference system and to output means for receiving command signals from said deduction inference system, said deduction inference system comprising:

memory storage means for storing a plurality of predetermined propositional logic clauses, each propositional logic clause defining the conditions under which at least one of a plurality of flags will be set in response to transmitted condition/status signals from said plurality of sensors;

means for selecting appropriate propositional logic expressions from said memory means in response to said transmitted condition/status signals and storing them in a working memory;

transformation formulae logic means for transforming said set of propositional logic clauses into a set of derivative clauses logically equivalent to said set of propositional logic clauses, wherein the set of derivative clauses does not contain "then" and "and" logical operators;

deducing means for performing deductions on the basis of said set of derivative clauses and said transmitted condition/status signals, said deducing means comprising;

means for identifying a unit clause containing a single variable "p" within said set of derivative clauses and removing said unit clause from said set of derivative clauses;

means for identifying compound clauses containing multiple variables within said set of derivative clauses;

means for searching said compound clauses for the variable "not p";

means for deleting the variable "not p" from each of said compound clauses to form a new set of derivative clauses, wherein said identifying means, said searching means, and said deleting means are repeatedly accessed until no more unit clauses containing a single variable can be identified; and

means for generating a solution on the basis of said deductions; and

means for generating command signals to said output means based on the solution from said deducing means, said output means including an actuator mechanism which, in response to said command signals, induces a physical response by transmitting activation signals to restore the stability of at least one device whose operation is directly or indirectly monitored by said plurality of sensors.

3. A deduction inference system coupled to a plurality of sensors for transmitting condition/status signals to said deduction inference system and to output means for receiving command signals from said deduction inference system, said deduction inference system comprising:

memory storage means for storing a plurality of predetermined propositional logic clauses, each propositional logic clause defining the conditions under which at least one of a plurality of flags will be set in response to transmitted condition/status signals from said plurality of sensors;

means for selecting appropriate propositional logic expressions from said memory means in response to said transmitted condition/status signals and storing them in a working memory;

transformation formulae logic means for transforming said set of propositional logic clauses into a set of derivative clauses logically equivalent to said set of propositional logic clauses, wherein the set of derivative clauses is smaller than the set of propositional logic clauses;

deducing means for performing deductions on the basis of said set of derivative clauses and said transmitted condition/status signals, said deducing means comprising;

means for identifying a unit clause containing a single variable "p" within said set of derivative clauses and removing said unit clause from said set of derivative clauses;

means for identifying compound clauses containing multiple variables within said set of derivative clauses;

means for searching said compound clauses for the variable "not p";

means for deleting the variable "not p" from each of said compound clauses to form a new set of derivative clauses, wherein said identifying means, said searching means, and said deleting means are repeatedly accessed until no more unit clauses containing a single variable can be identified; and

means for generating a solution on the basis of said deductions; and

means for generating command signals to said output means based on the solution from said deducing means, said output means including an actuator mechanism which, in response to said command signals, induces a physical response by transmitting activation signals to restore the stability of at least one device whose operation is directly or indirectly monitored by said plurality of sensors.

4. A deduction inference system coupled to a plurality of sensors for transmitting condition/status signals to said deduction inference system and to output means for receiving command signals from said deduction inference system, said deduction inference system comprising:

memory storage means for storing a plurality of predetermined propositional logic clauses, each propositional logic clause defining the conditions under which at least one of a plurality of flags will be set in response to transmitted condition/status signals from said plurality of sensors;

means for selecting appropriate propositional logic expressions from said memory means in response to said transmitted condition/status signals and storing them in a working memory;

transformation formulae logic means for transforming said set of propositional logic clauses into a set of derivative clauses logically equivalent to said set of propositional logic clauses, wherein the set of derivative clauses is larger than the set of propositional logic clauses;

deducing means for performing deductions on the basis of said set of derivative clauses and said transmitted condition/status signals, said deducing means comprising;

means for identifying a unit clause containing a signal variable "p" within said set of derivative clauses and removing said unit clause from said set of derivative clauses;

means for identifying compound clauses containing multiple variables within said set of derivative clauses;

means for searching said compound clauses for the variable "not p";

means for deleting the variable "not p" from each of said compound clauses to form a new set of derivative clauses, wherein said identifying means, said searching means, and said deleting means are repeatedly accessed until no more unit clauses containing a single variable can be identified; and

means for generating a solution on the basis of said deductions; and

means for generating command signals to said output means based on the solution from said deducing means, said output means including an actuator mechanism which, in response to said command signals, induces a physical response by transmitting activation signals to restore the stability of at least one device whose operation is directly or indirectly monitored by said plurality of sensors.