Fatma Mili

Reusing software: issues and research directions

Software productivity has been steadily increasing over the past 30 years, but not enough to close the gap between the demands placed on the software industry and what the state of the practice can deliver; nothing short of an order of magnitude increase in productivity will extricate the software industry from its perennial crisis. Several decades of intensive research in software engineering and artificial intelligence left few alternatives but software reuse as the (only) realistic approach to bring about the gains of productivity and quality that the software industry needs. In this paper, we discuss the implications of reuse on the production, with an emphasis on the technical challenges. Software reuse involves building software that is reusable by design and building with reusable software. Software reuse includes reusing both the products of previous software projects and the processes deployed to produce them, leading to a wide spectrum of reuse approaches, from the building blocks (reusing products) approach, on one hand, to the generative or reusable processor (reusing processes), on the other. We discuss the implication of such approaches on the organization, control, and method of software development and discuss proposed models for their economic analysis. Software reuse benefits from methodologies and tools to: (1) build more readily reusable software and (2) locate, evaluate, and tailor reusable software, the last being critical for the building blocks approach. Both sets of issues are discussed in this paper, with a focus on application generators and OO development for the first and a thorough discussion of retrieval techniques for software components, component composition (or bottom-up design), and transformational systems for the second. We conclude by highlighting areas that, in our opinion, are worthy of further investigation. >

Relational heuristics for the design of deterministic programs

SummaryIt has been shown that the design of deterministic programs can be formulated as the resolution of relational equations. Because relational calculi are not sufficiently structured, there are no algorithmic solutions to relational equations. In this paper, we formulate some heuristic solutions to these equations.

Handling fuzzy information in extended possibility-based fuzzy relational databases

Two kinds of fuzziness in attribute values of the fuzzy relational databases can be distinguished: One is that attribute values are possibility distributions, and the other is that there are resemblance relations in attribute domains. The fuzzy relational databases containing these two kinds of fuzziness simultaneously are called extended possibility‐based fuzzy relational databases. In this paper, we focus on such fuzzy relational databases. We classify two kinds of fuzzy data redundancies and define their removal. On this basis, we define fuzzy relational operations in relational algebra, which, being similar to the conventional relational databases, are complete and sound. In particular, we investigate fuzzy querying strategies and give the form of fuzzy querying with SQL.

Knowledge modeling for design decisions

Abstract In this paper, we share our experience in modeling and representing design knowledge relevant for engineering design decisions. We define an object model where classes are used to capture design standards and requirements relevant to designed objects. The traditional object model is customized to the representation of design knowledge in two major ways: (1) Classes representing design objects are augmented with design validation information. (2) Associations between classes are made explicit and used to reduce the redundancy and maintain the consistency of the knowledge. We define the semantics of the resulting object model and formulate the axioms that define its consistency. The object model is defined in the context of stamping design knowledge.

A relational division operator: the conjugate kernel

Abstract We discuss a binary operator on relations which has division like properties. We review the mathematical properties of this operator and then investigate its relevance to program construction.

Data dependencies in extended possibility-based fuzzy relational databases

Based on the semantic equivalence degree the formal definitions of fuzzy functional dependencies (FFDs) and fuzzy multivalued dependencies (FMVDs) are first introduced to the fuzzy relational databases, where fuzziness of data appears in attribute values in the form of possibility attributions, as well as resemblance relations in attribute domain elements, called extended possibility‐based fuzzy relational databases. A set of inference rules for FFDs and FMVDs is then proposed. It is shown that FFDs and FMVDs are consistent and the inference rules are sound and complete, just as Armstrongs axioms for classic cases.

Dynamic view of decision domains for the design of active DSS

Active decision support systems must be able to operate in two different modes. The traditional mode consists of their performing tasks under the explicit control of the user. The active mode consists of their performing some reasoning of their own and taking initiatives. The active mode requires that they have a knowledge-base related to the domain of the decision. The author addresses the contents and the organization of the knowledge base. A generic architecture is proposed; it integrates the database and the model base of the DSS (decision support system). The advantages of this architecture in the context of active as well as traditional DSS are discussed.<<ETX>>

Route guidance: State of the art vs. state of the practice

Route guidance is an essential component of intelligent transportation systems and a necessary ingredient to any automatic piloting system. Looking at the literature on Route Guidance, one can quickly see a chasm in how the problem is seen in the academic community and how it is seen in the automotive, industrial world. There seems to be different levels of interest in this problem and divergent assessment of its level of difficulty and the nature of challenges that are inhibiting its becoming a reality. In this paper, we examine the literature in the field, identify the prerequisites for a viable implementation of Route Guidance, and examine the state of development of each of these pre-requisites.

Fuzzy data compression based on data dependencies

In this article, we focus on the issues of fuzzy data dependencies. After introducing the notion of semantic equivalence degree, fuzzy functional and multivalued dependencies are defined. A set of sound and complete inference rules, similar to Armstrongs axioms for classic cases, for fuzzy functional dependencies (FFDs) and fuzzy multivalued dependencies (FMVDs) are proposed. The strategies and approaches for compressing fuzzy values by FFDs and FMVDs are investigated. By such processing, the unnecessary elements are eliminated from a fuzzy value and its range is compressed.

A relational model for the specification of data types

Abstract In this paper, we present an original specification model for data types. We discuss in turn its general form its axiomatic representation, its fixpoint semantic definition, an associated proof method, and a specification generation method. We illustrate our study with a relatively advanced example.