2021 IEEE 33rd International Conference on Tools with Artificial Intelligence (ICTAI), 2021
Linear algebraic characterization of logic programs has been investigated to perform logical infe... more Linear algebraic characterization of logic programs has been investigated to perform logical inference in large-scale knowledge bases and has gained encouraging results. In this paper, we further extend the linear algebraic characterization in abductive reasoning by exploiting the transpose of the program matrix. Then we propose an efficient exhaustive search strategy, which combines the flexibility and robustness of numerical computation with the compactness and efficiency of set operations, in order to compute solutions of abductive Horn propositional tasks. Experimental results demonstrate that our method is competitive with conflict-driven techniques and has the potential to speed up on parallel computing platforms.
COMMA 2012, Vienna " The science of Dialectic, in one sense of the word, is mainly concerned... more COMMA 2012, Vienna " The science of Dialectic, in one sense of the word, is mainly concerned to tabulate and analyse dishonest stratagems " Arthur Schopenhauer, The Art of Controversy (1896)
In this paper, we introduce methods of encoding propositional logic programs in vector spaces. In... more In this paper, we introduce methods of encoding propositional logic programs in vector spaces. Interpretations are represented by vectors and programs are represented by matrices. The least model of a definite program is computed by multiplying an interpretation vector and a program matrix. To optimize computation in vector spaces, we provide a method of partial evaluation of programs using linear algebra. Partial evaluation is done by unfolding rules in a program, and it is realized in a vector space by multiplying program matrices. We perform experiments using artificial data and real data, and show that partial evaluation has the potential for realizing efficient computation of huge scale of programs in vector spaces.
Given an observation or a goal, abduction infers candidate hypotheses to explain the observation ... more Given an observation or a goal, abduction infers candidate hypotheses to explain the observation or to achieve the goal. In this paper, we consider disjunctive abduction, in which disjunctions play important roles in abduction. Machine-oriented intelligent systems can utilize disjunctive abduction in many ways. For example, consider the case in which multiple explanations exist for an observation. We may need to select the best explanation among them, but often it is difficult to choose only one given insufficient information. In that case, we can leave the decision indefinite by considering a disjunctive explanation, which is a disjunction of possible alternative explanations. Disjunctive explanations can offer a consistent way to theory changes when they are incorporated or assimilated into the current knowledge base. The assimilated knowledge base preserves the intended semantics from the collection of all possible updated knowledge bases. A merit of disjunctive explanations is that we only need one current knowledge base at a time, still keeping every possible change in a single state. This method is extended to accomplish an update when there are multiple ways to remove old unnecessary hypotheses from the knowledge base. The proposed framework is well applicable to view updates in disjunctive databases. We also show that disjunctive abduction can be considered in inductive logic programming.
In this article, we first study abduction in human dialogues. Given an utterance, objective abduc... more In this article, we first study abduction in human dialogues. Given an utterance, objective abduction produces a hearer’s belief that could explain the utterance, while subjective abduction produces a hearer’s belief that could explain the belief state of a speaker. Different types of abduction are formulated using propositional epistemic logic. We next consider conversational implicature used as pragmatic inference in speech acts. Two conflicting implicatures, Q-implicature and I-implicature, are formulated and contrasted with abduction. We also argue how speakers could use abduction or conversational implicature for the purpose of misleading hearers.
1987 IEEE Third International Conference on Data Engineering, 1987
We assume a back-end type relational data base machine equipped with multiple dedicated engines f... more We assume a back-end type relational data base machine equipped with multiple dedicated engines for relational database operations. Response characteristics are evaluated, and some parallel control techniques are considered for improved response time by simulating the database machine in executing relational database operations using these engines in parallel.
Commonsense reasoning and machine learning are two important topics in AI. These techniques are r... more Commonsense reasoning and machine learning are two important topics in AI. These techniques are realized in logic programming as nonmonotonic logic programming (NMLP) and inductive logic programming (ILP), respectively. NMLP and ILP have seemingly different motivations and goals, but they have much in common in the background of problems. This article overviews the author's recent research results for realizing induction from nonmonotonic logic programs.
This paper studies a default logic for social reasoning in multiagent systems. A social default t... more This paper studies a default logic for social reasoning in multiagent systems. A social default theory is a collection of default theories with which each agent reasons and behaves by taking attitudes of other agents into account. The semantics of a social default theory is given as social extensions which represent the agreement of beliefs of individual agents in a society. We show the use of social default theories for representing social attitudes of agents and for reasoning in cooperative planning and negotiation among multiple agents.
This paper discusses a theory of nonmonotonic inheritance reasoning in a semantic network and pre... more This paper discusses a theory of nonmonotonic inheritance reasoning in a semantic network and presents a parallel inheritance algorithm based on this approach.
The article introduces a logical framework for negotiation among dishonest agents. The framework ... more The article introduces a logical framework for negotiation among dishonest agents. The framework relies on the use of abductive logic programming as a knowledge representation language for agents to deal with incomplete information and preferences. The article shows how intentionally false or inaccurate information of agents can be encoded in the agents' knowledge bases. Such disinformation can be effectively used in the process of negotiation to have desired outcomes by agents. The negotiation processes are formulated under the answer set semantics of abductive logic programming, and they enable the exploration of various strategies that agents can employ in their negotiation. A preliminary implementation has been developed using the ASP-Prolog platform.
This article studies a semantics of multiple logic programs, and synthesizes a program having suc... more This article studies a semantics of multiple logic programs, and synthesizes a program having such a collective semantics. More precisely, the following two problems are considered: given two logic programs P 1 and P 2 , which have the collections of answer sets AS ( P 1 ) and AS ( P 2 ), respectively; (i) find a program Q which has the set of answer sets such that AS ( Q ) = AS ( P 1 ) ∪ AS ( P 2 ); (ii) find a program R which has the set of answer sets such that AS ( R ) = AS ( P 1 ) ∩ AS ( P 2 ). A program Q satisfying the condition (i) is called generous coordination of P 1 and P 2 ; and R satisfying (ii) is called rigorous coordination of P 1 and P 2 . Generous coordination retains all of the answer sets of each program, but permits the introduction of additional answer sets of the other program. By contrast, rigorous coordination forces each program to give up some answer sets, but the result remains within the original answer sets for each program. Coordination provides a pro...
2021 IEEE 33rd International Conference on Tools with Artificial Intelligence (ICTAI), 2021
Linear algebraic characterization of logic programs has been investigated to perform logical infe... more Linear algebraic characterization of logic programs has been investigated to perform logical inference in large-scale knowledge bases and has gained encouraging results. In this paper, we further extend the linear algebraic characterization in abductive reasoning by exploiting the transpose of the program matrix. Then we propose an efficient exhaustive search strategy, which combines the flexibility and robustness of numerical computation with the compactness and efficiency of set operations, in order to compute solutions of abductive Horn propositional tasks. Experimental results demonstrate that our method is competitive with conflict-driven techniques and has the potential to speed up on parallel computing platforms.
COMMA 2012, Vienna " The science of Dialectic, in one sense of the word, is mainly concerned... more COMMA 2012, Vienna " The science of Dialectic, in one sense of the word, is mainly concerned to tabulate and analyse dishonest stratagems " Arthur Schopenhauer, The Art of Controversy (1896)
In this paper, we introduce methods of encoding propositional logic programs in vector spaces. In... more In this paper, we introduce methods of encoding propositional logic programs in vector spaces. Interpretations are represented by vectors and programs are represented by matrices. The least model of a definite program is computed by multiplying an interpretation vector and a program matrix. To optimize computation in vector spaces, we provide a method of partial evaluation of programs using linear algebra. Partial evaluation is done by unfolding rules in a program, and it is realized in a vector space by multiplying program matrices. We perform experiments using artificial data and real data, and show that partial evaluation has the potential for realizing efficient computation of huge scale of programs in vector spaces.
Given an observation or a goal, abduction infers candidate hypotheses to explain the observation ... more Given an observation or a goal, abduction infers candidate hypotheses to explain the observation or to achieve the goal. In this paper, we consider disjunctive abduction, in which disjunctions play important roles in abduction. Machine-oriented intelligent systems can utilize disjunctive abduction in many ways. For example, consider the case in which multiple explanations exist for an observation. We may need to select the best explanation among them, but often it is difficult to choose only one given insufficient information. In that case, we can leave the decision indefinite by considering a disjunctive explanation, which is a disjunction of possible alternative explanations. Disjunctive explanations can offer a consistent way to theory changes when they are incorporated or assimilated into the current knowledge base. The assimilated knowledge base preserves the intended semantics from the collection of all possible updated knowledge bases. A merit of disjunctive explanations is that we only need one current knowledge base at a time, still keeping every possible change in a single state. This method is extended to accomplish an update when there are multiple ways to remove old unnecessary hypotheses from the knowledge base. The proposed framework is well applicable to view updates in disjunctive databases. We also show that disjunctive abduction can be considered in inductive logic programming.
In this article, we first study abduction in human dialogues. Given an utterance, objective abduc... more In this article, we first study abduction in human dialogues. Given an utterance, objective abduction produces a hearer’s belief that could explain the utterance, while subjective abduction produces a hearer’s belief that could explain the belief state of a speaker. Different types of abduction are formulated using propositional epistemic logic. We next consider conversational implicature used as pragmatic inference in speech acts. Two conflicting implicatures, Q-implicature and I-implicature, are formulated and contrasted with abduction. We also argue how speakers could use abduction or conversational implicature for the purpose of misleading hearers.
1987 IEEE Third International Conference on Data Engineering, 1987
We assume a back-end type relational data base machine equipped with multiple dedicated engines f... more We assume a back-end type relational data base machine equipped with multiple dedicated engines for relational database operations. Response characteristics are evaluated, and some parallel control techniques are considered for improved response time by simulating the database machine in executing relational database operations using these engines in parallel.
Commonsense reasoning and machine learning are two important topics in AI. These techniques are r... more Commonsense reasoning and machine learning are two important topics in AI. These techniques are realized in logic programming as nonmonotonic logic programming (NMLP) and inductive logic programming (ILP), respectively. NMLP and ILP have seemingly different motivations and goals, but they have much in common in the background of problems. This article overviews the author's recent research results for realizing induction from nonmonotonic logic programs.
This paper studies a default logic for social reasoning in multiagent systems. A social default t... more This paper studies a default logic for social reasoning in multiagent systems. A social default theory is a collection of default theories with which each agent reasons and behaves by taking attitudes of other agents into account. The semantics of a social default theory is given as social extensions which represent the agreement of beliefs of individual agents in a society. We show the use of social default theories for representing social attitudes of agents and for reasoning in cooperative planning and negotiation among multiple agents.
This paper discusses a theory of nonmonotonic inheritance reasoning in a semantic network and pre... more This paper discusses a theory of nonmonotonic inheritance reasoning in a semantic network and presents a parallel inheritance algorithm based on this approach.
The article introduces a logical framework for negotiation among dishonest agents. The framework ... more The article introduces a logical framework for negotiation among dishonest agents. The framework relies on the use of abductive logic programming as a knowledge representation language for agents to deal with incomplete information and preferences. The article shows how intentionally false or inaccurate information of agents can be encoded in the agents' knowledge bases. Such disinformation can be effectively used in the process of negotiation to have desired outcomes by agents. The negotiation processes are formulated under the answer set semantics of abductive logic programming, and they enable the exploration of various strategies that agents can employ in their negotiation. A preliminary implementation has been developed using the ASP-Prolog platform.
This article studies a semantics of multiple logic programs, and synthesizes a program having suc... more This article studies a semantics of multiple logic programs, and synthesizes a program having such a collective semantics. More precisely, the following two problems are considered: given two logic programs P 1 and P 2 , which have the collections of answer sets AS ( P 1 ) and AS ( P 2 ), respectively; (i) find a program Q which has the set of answer sets such that AS ( Q ) = AS ( P 1 ) ∪ AS ( P 2 ); (ii) find a program R which has the set of answer sets such that AS ( R ) = AS ( P 1 ) ∩ AS ( P 2 ). A program Q satisfying the condition (i) is called generous coordination of P 1 and P 2 ; and R satisfying (ii) is called rigorous coordination of P 1 and P 2 . Generous coordination retains all of the answer sets of each program, but permits the introduction of additional answer sets of the other program. By contrast, rigorous coordination forces each program to give up some answer sets, but the result remains within the original answer sets for each program. Coordination provides a pro...
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