There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

物件導向軟體之架構(Object-Oriented Software Construction)探討

This paper gives an overview of the development of the field of Knowledge Engineering over the last 15 years. We discuss the paradigm shift from a transfer view to a modeling view and describe two approaches which considerably shaped research in Knowledge Engineering: Role-limiting Methods and Generic Tasks. To illustrate various concepts and methods which evolved in recent years we describe three modeling frameworks: CommonKADS, MIKE and PROTEGE-II. This description is supplemented by discussing some important methodological developments in more detail: specification languages for knowledge-based systems, problem-solving methods and ontologies. We conclude by outlining the relationship of Knowledge Engineering to Software Engineering, Information Integration and Knowledge Management.

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Knowledge engineering: principles and methods

An Introduction to MultiAgent Systems.

Aspect] is a simple and practical aspect-oriented extension to Java With just a few new constructs, AspectJ provides support for modular implementation of a range of crosscutting concerns. In AspectJ's dynamic join point model, join points are well-defined points in the execution of the program; pointcuts are collections of join points; advice are special method-like constructs that can be attached to pointcuts; and aspects are modular units of crosscutting implementation, comprising pointcuts, advice, and ordinary Java member declarations. AspectJ code is compiled into standard Java bytecode. Simple extensions to existing Java development environments make it possible to browse the crosscutting structure of aspects in the same kind of way as one browses the inheritance structure of classes. Several examples show that AspectJ is powerful, and that programs written using it are easy to understand.

An overview of AspectJ

Publisher Summary 
An algebraic specification is a description of one or more abstract data types. There are three main semantic approaches to algebraic specifications: (1) the initial algebra approach, (2) the terminal algebra approach, and (3) the loose approach. A fourth approach that is mainly of theoretical interest uses iso-initial algebras. This chapter reviews the basic concepts for the theory of algebraic specifications. It also describes the notion of an abstract data type and discusses its basic properties. The chapter also describes four other semantic concepts and algebras for specifying nondeterminism and concurrency. The chapter discusses the existence of initial and terminal algebras, the lattice structure of the models, and the expressive power of initial and terminal algebra specifications. The chapter also presents two additional concepts for algebraic specifications, which are both practically and theoretically essential: (1) hidden symbols and (2) constructors. The chapter also presents a general approach to structured specifications.

Algebraic specification

We present a method using an extended logical system for obtaining programs from specifications written in a sublanguage of CASL. These programs are “correct” in the sense that they satisfy their specifications. The technique we use is to extract programs from proofs in formal logic by techniques due to Curry and Howard. The logical calculus, however, is novel because it adds structural rules corresponding to the standard ways of modifying specifications: translating (renaming), taking unions, and hiding signatures. Although programs extracted by the Curry-Howard process can be very cumbersome, we use a number of simplifications that ensure that the programs extracted are in a language close to a standard high-level programming language. We use this to produce an executable refinement of a given specification and we then provide a method for producing a program module that maximally respects the original structure of the specification. Throughout the paper we demonstrate the technique with a simple example.

/pdf/extraction-of-structured-programs-from-specification-proofs-3pwsr830ip.pdf

Extraction of Structured Programs from Specification Proofs

We present a method using an extended logical system for obtaining programs from specifications written in a sublanguage of CASL. These programs are correct in the sense that they satisfy their specifications. The technique we use is to extract programs from proofs in formal logic by techniques due to Curry and Howard. The logical calculus, however, is novel because it adds structural rules corresponding to the standard ways of modifying specifications: translating (renaming), taking unions, and hiding signatures. Although programs extracted by the Curry-Howard process can be very cumbersome, we use a number of simplifications that ensure that the programs extracted are in a language close to a standard high-level programming language. We use this to produce an executable refinement of a given specification and we then provide a method for producing a program module that maximally respects the original structure of the specification. Throughout the paper we demonstrate the technique with a simple example.

Extraction of structured programs from specification proofs

The IST-FET Integrated Project SENSORIA aims at developing a novel comprehensive approach to the engineering of service-oriented software systems where foundational theories, techniques and methods are fully integrated in a pragmatic software engineering approach. Process calculi and logical methods serve as the main mathematical basis of the SENSORIA approach.

In this paper we give first a short overview of SENSORIA and then focus on process calculi for service-oriented computing. The Service Centered Calculus SCC is a general purpose calculus which enriches traditional process calculi with an explicit notion of session; the Service Oriented Computing Kernel SOCK is inspired by the Web services protocol stack and consists of three layers for service description, service engines, and the service network; Performance Evaluation Process Algebra (PEPA) is an expressive formal language for modelling distributed systems which we use for quantitative analysis of services. The calculi and the analysis techniques are illustrated by a case study in the area of distributed e-learning systems.

/pdf/sensoria-process-calculi-for-service-oriented-computing-21dmby4amr.pdf

SENSORIA process calculi for service-oriented computing

/pdf/leveraging-applications-of-formal-methods-verification-and-2jz05aj0gt.pdf

Martin Wirsing

Papers

Algebraic specification

Extraction of Structured Programs from Specification Proofs

Extraction of structured programs from specification proofs

SENSORIA process calculi for service-oriented computing

Leveraging Applications of Formal Methods, Verification and Validation