Hidekatsu Koike

Program generation in the equivalent transformation computation model using the squeeze method

In the equivalent transformation (ET) computation model, a specification provides background knowledge in a problem domain, a program is a set of prioritized rewriting rules, and computation consists in successive reduction of problems by rule application. As long as meaning-preserving rewriting rules, called ET rules, with respect to given background knowledge are used, correct computation results are guaranteed. In this paper, a general framework for program synthesis in the ET model is described. The framework comprises two main phases: (1) equivalent transformation of specifications, and (2) generation of a program from an obtained specification. A method for program generation in the second phase, called the squeeze method, is presented. It constructs a program by accumulation of ET rules one by one on demand, with the goal of producing a correct, efficient, and nonredundant program.

A programming language interpreter system based on equivalent transformation

Both correctness and efficiency of software are becoming increasingly critical as computer systems become more important in our lives. Due to the emergence of ubiquitous computing, there are far more software systems than before and it is getting increasingly difficult to fix and tune all of them, according to their current situations, by hand. One solution to this problem is the use of the adaptive software which modifies itself to fit its environment. However, it seems to have no rigorous theory for correctness. In many cases, correct computations are regarded as a sequence of equivalent transformations. In the equivalent transformation (ET) computation model, all the procedures are represented by a sequence of equivalent transformations, and we can achieve both correctness and efficiency of programs by rigorous theory. We have developed ETL, which is a programming language to describe programs based on the model, and a programming language interpreter system ETI. In this paper, we present the ETI which can correctly and efficiently solve problems which are difficult to solve by conventional approaches.

Equivalent Transformation by Safe Extension of Data Structures

Equivalent transformation has been proposed as a methodology for providing programs with appropriate data structures. For instance, logic programs which use lists are transformed into equivalent programs that use difference-lists. However lists and difference-lists are both usual terms and in this sense no new data structures are introduced in the transformation. Since logic programming has fixed data structure called terms, no one can develop theoretical foundations for introducing new data structures into programs as far as only logic programs are discussed. In this paper we develop a theoretical foundation of equivalent transformation that introduces new data structures. We introduce a parameter G for data structures, by which many languages with different data structures are characterized. By changing this parameter (say from G1 to G2) we can discuss data structure change for programs. We define a concept ofsaf e extension ofdata structures, and prove that the meaning ofa program on a data structure is preserved by safe extension of the data structure.

Program synthesis based on the equivalent transformation computation model

Effective generation of efficient and correct programs from specifications is the underlying design motivation of the Equivalent Transformation (ET) computation model. This concise paper explains how the ET model satisfies major required features of a program synthesis framework, and outlines a three-phase program synthesis method.

A Theoretical Foundation of Program Synthesis by Equivalent Transformation

Equivalent transformation (ET) is useful for synthesis and transformation of programs. However, it is not so clear what semantics should be preserved in synthesis and transformation of programs in logic and functional programming, which come from the disagreement of computation models (inference or evaluation) and equivalent transformation. To overcome the difficulty, we adopt a new computation model, called equivalent transformation model, where equivalent transformation is used not only for program synthesis, but also for computation. We develop a simple and general foundation for computation and program synthesis, and prove the correctness ofET-based program synthesis.

Parallel processing method based on equivalent transformation

Hidekatsu Koike Faculty of Social Information Sapporo Gakuin University 1 1-banchi Bunkyoudai, Ebetsu Hokkaido 069-8555, Japan koike@edu.sgu.ac.jp Hiroshi Mabuchi Faculty of Software and Information Science Iwate Prefectural University 152-52 Sugo, Takizawa Iwate 020-0193, Japan mabu@soft. iwate-pu.ac.jp Yusuke Saito Faculty of Computer Science Hokkaido University Kita 11, Nishi 5, Kita-ku Sapporo 060-0811, Japan ysait@uva.cims.hokudai.ac.jp

Solving Query-Answering Problems for the Semantic Web Using Equivalent Transformation

knowledge of the problem are converted into a conjunction of first-order formulas, which is further converted by meaning-preserving Skolemization into a set of extended clauses typically containing global existential quantifications of function variables. The obtained clause set is then transformed successively using ET rules until the answer set of the original problem can be readily derived. ET rules for unfolding extended clauses, for removing useless extended clauses, and for dealing with function variables are presented. Application of the framework is illustrated.

Deterministic-Rule Programs on Specialization Systems: Clause-Model Semantics

Deterministic-rule programs provide a bridge between rule-based nondeterministic programs and deterministic programs in imperative languages. In this paper, we formulate deterministic-rule programs on a specialization system and formalize their procedural semantics, called the clause-model semantics, based on a general framework for discussing the semantics of procedures with a conditional state-transition structure. The proposed theory establishes a general class of deterministic-rule programs with their precise semantics, providing a basis for developing methods for synthesis of deterministic programs from declarative descriptions. Taking a specialization system as a parameter, the theory is applicable to many concrete classes of deterministic-rule programs with various forms of data structures through parameter instantiation.