978-1-4673-7681-5 ©2015 IEEE 638
2015 12th International Conference on Fuzzy Systems and Knowledge Discovery (FSKD'15)
An Algorithm for Extension of Clausal Beliefs
GUO Qian
Information Science and Technology College. Dalian
Maritime University
Dalian Maritime University, DMU
Dalian, China
DENG An-sheng
Information Science and Technology College. Dalian
Maritime University
Dalian Maritime University, DMU
Dalian, China
Abstract—In order to reason for the conflicting beliefs, this paper
employs the conclusion that does not contain opposite
information as the hypothesis expansion. Furthermore, it
provides the definition of hypothesis extension based on the
method of belief non-revision. The hypothesis expansion has a
series of good mathematical properties, e.g., consistency and
closeness. This paper proposes the algorithm for extension of
clausal beliefs based on the definition and its good nature.
Although the number of clausal beliefs may decrease the working
speed of the algorithm, the correctness of the corresponding
conclusion is enhanced. The experimental results demonstrate
that, for a certain amount of beliefs, the efficiency of proposed
approach still can be guaranteed.
Keywords-hypothesist; non-revision belief; expansion
I. INTRODUCTION
Recently, many efforts have been paid to exploit a variety
of common sense reasoning technologies. However, the
process of reasoning appears the problems of monotonic,
inaccurate and incompatible
[1]
. We called the contradictive
common sense as belief
[2]
. The research for the processing
method of inconsistent beliefs is an important aspect in
artificial intelligence area.
There are many important research results about the field
of the common sense reasoning. McDermott and Doyle
proposed the theory of non-monotonic logic
[3]
and the related
theory based on modal logic
[4]
. Reiter proposed the theory of
default logic
[5]
. A few years later, the equivalence relation
between the default logic and the auto-epistemic logic
[6]
have
proved by Konolige. Until the mid of 1980s, Gardenfors,
Alchourron and Makinsond founded the famous theory of
belief revision
[7]
, it can also be named as AGM
[8]
.
However, under the condition that is lack of heuristic
information, the method of belief revision is more difficult to
reasoning, and it cloud lead to the system loss the important
information or bring unfavorable information. Therefore, we
put forward the theory of the non-revision belief
[9]
.
The set of hypothesis expansion means the set of
conclusion that does not contain opposite information. It does
not make any correct operation to inconsistent beliefs. This
paper provides the definition of hypothesis extension based on
the method of belief non-revision. It proves that each
hypothesis has the only expansion. This paper proposes the
algorithm for extension of clausal beliefs based on the
definition and its good nature. It can reduce the loss of
important information and improve the precision of reasoning
by using the method of non-revision belief. The experimental
results demonstrate the process of reasoning is correct.
II. T
HEORETICAL BASIS
A. The Definitions of the Propositional Logic
In this paper, the hypothesis is limited to the propositional
logic. The hypothesis expansion is defined with the general
resolution principle.
Definition 1 Proposition is a statement that affirms or
denies something and is either true or false.
Proposition can be divided into the atomic proposition and
the complex proposition.
The atomic proposition is consist of some simple
statements, as the following formula shows:
()
,,1
iii
PQR PQRi≥L,,
The logical connection symbols used in this paper are as the
follows: