摘要:

AbstractSince the introduction of Smalltalk, the object‐oriented approach towards the organization of data and programs has become popular. In this paper the possibilities of exploiting procedure‐oriented languages to allow an object‐oriented style of programming are analysed. Although the two approaches are apparently dissimilar, a family of procedure‐oriented languages is described which allows a high degree of freedom in programming and does not appear to restrain the programmer within the procedure‐oriented scheme. Popular languages of this family are ML and PS‐Algol. For such languages, a technique is developed which enables an efficient implementation of object‐oriented features, such as the subclassing form of inheritance provided by Smalltalk

ISSN:0038-0644    

DOI:10.1002/spe.4380180402

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe portability of software has become a major commercial issue in recent times. Such portability does not come easily, as few if any computer languages are really portable in practice. An additional complicating factor, especially in the commercial environment, is that the resulting software must be efficient. This paper describes the design and successful implementation of a 500,000+ line portable FORTRAN 77 package for the processing of seismic data. The package exhibits demonstrably high efficiency on a wide variety of machines from minicomputers to the largest supercomputers. Experiences gained during this exercise throw much light on the integration of the various thought processes which occur during the software engineering cycle, especially the notion of locality.

ISSN:0038-0644    

DOI:10.1002/spe.4380180403

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractIn a distributed system based on Transputer components there is one clock for each processing element, and the definition of the global system time requires the choice of a hardware or software synchronization method. This paper describes the RING_SYNC algorithm, based on a ring‐structured synchronization scheme. RING_SYNC has no provision for fault tolerance, but it introduces little overhead, thanks to the optimization of both the number of messages exchanged at sync time and the resynchronization frequency. The implementation of the algorithm together with the tests performed for measuring the synchronization error and their results are discussed extensively, and some typical applications are pointed ou

ISSN:0038-0644    

DOI:10.1002/spe.4380180404

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper describes an experimental implementation of the Edison programming language for a network of microcomputers based on the Z‐80 microprocessor. The resulting Edison‐N system allows parallel execution of concurrent processes. Its aim is to assist in teaching the principles of concurrent programm

ISSN:0038-0644    

DOI:10.1002/spe.4380180405

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractLOTOS is an executable specification language for distributed systems currently being standardized within ISO as a tool for the formal specification of open systems interconnection protocols and services. It is based on an extended version of Milner's calculus of communicating systems (CCS) and on ACT ONE abstract data type (ADT) formalism. A brief introduction to LOTOS is given, along with a discussion of LOTOS operational semantics, and of the executability of LOTOS specifications. Further, an account of a prototype LOTOS interpreter is given, which includes an interactive system that allows the user to direct the execution of a specification (for example, for testing purposes). The interpreter was implemented in YACC/LEX, C and Prolog. The following topics are discussed: syntax and static semantics analysis; translation from LOTOS external format to internal representation; evaluation of ADT value expressions and extended CCS behaviour expressions. It is shown that the interpreter can be used in a variety of ways: to recognize whether a given sequence of interactions is allowed by the specification; to generate randomly chosen sequences of interactions; in a user‐guided generation mode, et

ISSN:0038-0644    

DOI:10.1002/spe.4380180406

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractApproximate string matching is an important operation in information systems because an input string is often an inexact match to the strings already stored. Commonly known accurate methods are computationally expensive as they compare the input string to every entry in the stored dictionary. This paper describes a two‐stage process. The first uses a very compactn‐gram table to preselect sets of roughly similar strings. The second stage compares these with the input string using an accurate method to give an accurately matched set of strings. A new similarity measure based on the Levenshtein metric is defined for this comparison. The resulting method is both computationally fast and storage‐effi

ISSN:0038-0644    

DOI:10.1002/spe.4380180407

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380180401

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY