Takushi Tanaka

Expert System Applications

The volume presents an international collection of mature expert system projects. Work from countries ranging from Japan to France, Spain to China, and from the United States is reported. Following on the second stage of expert system development, discussion focusses on issues that have become prominent through the application of systems to real-world problems. The incorporation of substantial numeric knowledge into systems is the first issue covered. It arises in many technical domains, which are likely to have already been subject to statistical or algebraic description. The second issue concerns the explicit representation of control knowledge within knowledge-bases. This gives systems the capability of explicitly reasoning about the control strategy applicable to each sub-problem arising in a complex problem domain.

Definite-clause set grammars: a formalism for problem solving

Abstract First, we present definite-clause set grammars (DCSG), a DCG-like formalism for free-word-order languages. The DCSG formalism is well suited for problem solving. By dealing with DCSG as a generalized parsing problem, we avoid a certain type of looping problem in backward chaining. Next, we extend DCSG by viewing grammar rules as definitions for set conversions. In order to realize inverse conversions, we introduce an inverse operator into DCSG syntax. This operator enables partial bottom-up analyses in the DCSG top-down parsing process. Next, we discuss a looping problem called “left recursion” in top-down parsing. The looping problem is avoided by the bottom-up mechanism of the extended DCSG. The bottom-up mechanism can be viewed as the top-down controlled firing of production rules. Unlike most production systems, production systems written in extended DCSG can backtrack and produce alternative solutions. DCSG is a simple but powerful tool for generalized parsing problems which involve finding structures in a given data set.

Parsing electronic circuits in a logic grammar

Understanding circuits is a prerequisite for circuit design and trouble shooting. Circuit understanding by engineers is described as a process that starts with a structural analysis and then proceeds to a causal analysis. As a step toward automatic circuit understanding, a method for analyzing circuit structures is presented. In this method, a circuit is reviewed as a sentence and its elements as words. Circuit structures are defined by rules written in a logic grammar called definite clause set grammar (DCSG). Given circuits are decomposed into parse trees by the DCSG top-down parsing mechanism. These parse trees represent hierarchical structures of functional blocks. This representation is presented as one step in the process of automatic understanding of circuit structures. >

Circuit grammar: knowledge representation for structure and function of electronic circuits

As a step toward the automatic understanding of electronic circuits, we present a logic grammar as a new method of knowledge representation for structure and function of electronic circuits. In this work, we view a circuit as a sentence and its elements as words. Circuit structures are then defined by grammar rules. A set of grammar rules, when converted into Prolog clauses, forms a logic program winch performs top-down parsing. A circuit is designed to perform specific functions to achieve its goal. We see these functions as the meaning of the circuit. This new circuit grammar defines not only the syntactic structures of circuits, but also their relations to the functions. When a given circuit is parsed as a grammatical sentence, not only its syntactic structure but also its functions are derived. A simple English interface generates explanations on the circuit structure and functions.

Overview and operations of CubeSat FITSAT-1 (NIWAKA)

FITSAT-1 (NIWAKA) is a 10 cm 1U CubeSat which was deployed from ISS/JEM on October 4, 2012. The main mission of NIWAKA is to demonstrate a high speed transmitter module developed by our group (115.2 kbps, 5.8 GHz, FSK, 2 W RF output). It can transmit VGA resolution jpeg images (640×480 pixels) in 2 to 6 seconds. The secondary mission is to make the satellite twinkle as an “artificial star” using high-output LEDs. This light was observed by binoculars, imaged by cameras, and detected by a photo-multiplier mounted on a telescope. We also discovered a phenomenon of increasing rotation of NIWAKA.

Deriving electrical dependencies from circuit topologies using logic grammar

In this paper, a new logic grammar for knowledge representation of electronic circuits has been developed. The grammar rules not only define the syntactic structure of electronic circuits, but also allow us to derive the meaning of a given circuit as relationships between its syntactic structure and basic circuit functions. This paper shows how voltage and current dependencies are coded in this new circuit grammar and how these dependencies are derived by parsing circuit topologies.

A Logic Grammar for Circuit Analysis

We have developed a logic grammar for circuit analysis. Circuits are viewed as sentences, and their elements as words. Circuit structures are defined by logic grammar called DCSG. A set of grammar rules, when converted into Prolog clauses, forms a logic program which execute top-down parsing. When we apply our methods to fundamental circuit analysis, problems of recursive definition occur. Recursive definitions often cause looping problems in logic programming. We will discusses several problems of recursive definition in circuit analysis.

A mechanism for converting circuit grammars to definite clauses

The circuit grammar is a logic grammar developed for knowledge representation of electronic circuits. Knowledge of circuit structures and their functions are coded as grammar rules. Those grammar rules, when converted into definite clauses, form a logic program that can parse given circuits and derive their electrical behavior. This paper shows a mechanism for converting circuit grammar rules into definite clauses.

Deriving Electrical Dependencies from Circuit Topologies Using Logic Grammar

We have developed a new logic grammar for knowledge representation of electronic circuits. The grammar rules not only define the syntactic structure of electronic circuits, but also allow us to derive the meaning of a given circuit as relationships between its syntactic structure and basic circuit functions. In this paper, we show how voltage and current dependencies are coded in this new circuit grammar and how these dependencies are derived by parsing circuit structures.

Structural Analysis of Electronic Circuits in a Deductive System

As a step toward automatic circuit understanding, we have developed methods for structural analysis of electronic circuits in a deductive system called Duck. We first show how circuits are represented in logic. Corresponding to each circuit elment or device, a predicate is defined. Circuits are defined using those predicates. Circuit analysis is done as an iteration of proofs which determine the basic structures in the circuit.