An empirical study into COBOL type inferencing

AbstractIn a typical COBOL program, the data division consists of 50% of the lines of code. Automatic type inference can help to understand the large collections of variable declarations contained therein, showing how variables are related based on their actual usage. The most problematic aspect of type inference is pollution, the phenomenon that types become too large, and contain variables that intuitively should not belong to the same type. The aim of the paper is to provide empirical evidence for the hypothesis that the use of subtyping is an effective way for dealing with pollution. The main results include a tool set to carry out type inference experiments, a suite of metrics characterizing type inference outcomes, and the experimental observation that only one instance of pollution occurs in the case study conducted

Automated Refactoring of Legacy Java Software to Enumerated Types

Modern Java languages introduce several new features that offer significant improvements over older Java technology. In this article we consider the new enum construct, which provides language support for enumerated types. Prior to recent Java languages, programmers needed to employ various patterns (e.g., the weak enum pattern) to compensate for the absence of enumerated types in Java. Unfortunately, these compensation patterns lack several highly-desirable properties of the enum construct, most notably, type safety. We present a novel fully-automated approach for transforming legacy Java code to use the new enumeration construct. This semantics-preserving approach increases type safety, produces code that is easier to comprehend, removes unnecessary complexity, and eliminates brittleness problems due to separate compilation. At the core of the proposed approach is an interprocedural type inferencing algorithm which tracks the flow of enumerated values. The algorithm was implemented as an open source, publicly available Eclipse plug-in and evaluated experimentally on 17 large Java benchmarks. Our results indicate that analysis cost is practical and the algorithm can successfully refactor a substantial number of fields to enumerated types. This work is a significant step towards providing automated tool support for migrating legacy Java software to modern Java technologies

An overview of decision table literature 1982-1995.

This report gives an overview of the literature on decision tables over the past 15 years. As much as possible, for each reference, an author supplied abstract, a number of keywords and a classification are provided. In some cases own comments are added. The purpose of these comments is to show where, how and why decision tables are used. The literature is classified according to application area, theoretical versus practical character, year of publication, country or origin (not necessarily country of publication) and the language of the document. After a description of the scope of the interview, classification results and the classification by topic are presented. The main body of the paper is the ordered list of publications with abstract, classification and comments.

Implementation of Combat Simulation Through Expert Support Systems

The battlefield simulation is often faced with a bewildering array of conflicting stresses and challenges. Communication is currently slower and more costly than computation. Expert System technologies such as production rule systems allow one to acquire and represent the collection of heuristic rules in computer compatible form. The system also include master control programs that determine the order in which these rules should be applied against the monitored system performance to arrive at appropriate system control. These expert systems are used in two nodes, both as an intelligence assistant to the expert, amplifying the capacity and quality of his work, and as a surrogate for an expert when he is not available. An Expert support System (ESS) designed and developed for combat simulation has been enumerated in this article. The quality and the reliability of the inferred tactical situation is improved by using PROLOG. This formal AI language is used for validating and checking sensor detections for consistency and logical plausibility. The supremacy of PROLOG for creating and interrogating a data base helps maintaining a reasonably coherent feature of the tactical situation. The perils and pitfalls of tackling with expert systems have also been underscored

Italian allora, French alors : functions, convergences and divergences

The functions, convergences, and divergences of Italian allora and French alors are analyzed in two Italian texts (the Novellino, in Old Italian, and Paso Doble, in Modern Italian) and their French translations. The discourse marker is used differently in the two languages, and the contrastive analysis allows us to better assess those differences, by explicitly quantifying the degree of correspondence, omissions, and non-literal translations. Furthermore, our work confirms the existence of functions which may be identified as more central or more peripheral within a certain configuration, and emphasizes the existence of cross-language preferences for a more/less rich set of forms for expressing a particular function. The polyfunctionality and context-boundness which characterize discourse markers in general are held responsible for differences in translation, thus motivating the several shades of meaning which distinguish Italian allora (with regard both to Old and Modern Italian) from French alors.En aquest article analitzem les funcions, les convergències i les divergències del connector italià allora i del francès alors a partir de dos textos italians (Novellino, en italià antic, i Paso Doble, en italià actual) i les corresponents traduccions franceses. Aquest marcador del discurs s'utilitza de manera diferent en les dues llengües com l'anàlisi contrastiva permet posar de manifest quantificant explícitament el grau de correspondència, omissions i traduccions no literals. Més encara, aquest treball confirma l'existència de funcions que poden ser identificades com a més centrals o més perifèriques dins d'una certa configuració i també manifesta l'existència de preferències interlingüístiques en un grup de formes més o menys ric per a expressar una funció particular. La polifuncionalitat i la dependència contextual que caracteritza els marcadors del discurs en general expliquen les diferències de traducció i, per tant, motiven els diferents matisos de significat que diferencien allora (tant respecte a l'italià antic com a l'actual) del marcador francès alors

Building expert systems: cognitive emulation.

Chapter 1 briefly introduces the concept of cognitive emulation, and outlines its current status. Chapter 2 reviews psychological research on human expert thinking. First, the study of expert thinking is placed in the context of modern cognitive psychology. Next, the principal methods and techniques employed by psychologists examining expert cognition are examined. The remainder of the chapter is given over to a review of the published literature on the nature and development of human expertise. Chapter 3 reviews the main arguments for and against cognitive emulation in expert system design. The tentative conclusion reached is that a significant degree of emulation is inevitable, but that a pure, unselective strategy of emulation is neither realistic nor desirable. Chapter 4 examines the prospects for cognitive emulation from a more pragmatic angle. Several factors are identified that represent constraints on the usefulness of a cognitive approach. However, a second set of factors is identified which should facilitate an emulation strategy - especially in the longer term. Some guidance is given on when to seriously consider adopting an emulation strategy. Chapter 5 presents a critical survey of expert system research that has already addressed the emulation issue. Six basic approaches to cognitive emulation are distinguished and evaluated. This helps draw out in more detail the implications of an emulation strategy for knowledge acquisition, knowledge representation and system architecture. The chapter concludes by discussing the issues that arise when different approaches to emulation are combined. Some guidance is offered on how this might be achieved. Chapter 6 summarizes the main themes and issues to have emerged, the design advice contained in the thesis, and the original contributions made by the thesis

Knowledge, programming, and programming cultures: LISP, C, and Ada

The results of research 'Ada as an implementation language for knowledge based systems' are presented. The purpose of the research was to compare Ada to other programming languages. The report focuses on the programming languages Ada, C, and Lisp, the programming cultures that surround them, and the programming paradigms they support

USING RESTRICTED NATURAL LANGUAGE FOR DATA RETRIEVAL: A PLAN FOR FIELD EVALUATION

One strategy that has been proposed for dealing with the growing backlog for development of applications is to give casual users languages for interacting directly with databases. Yet, there is little agreement on the form such languages should take. Should they be natural-like, conforming closely to a user's native tongue or should they be structured to take advantage of the characteristics of formal languages? This paper presents the rationale for and design of a field evaluation of natural language for data retrieval. The natural language system and application are described along with the research design of the project. The results of the first part of the study, a laboratory experiment to investigate whether users perform better with an artificial or natural language, suggest that after equal amounts of training no difference in subject performance is found between languages using a paper and pencil test . The insights gained to date are summarized.Information Systems Working Papers Serie