SequenceL is a concise, high-level language with a simple semantics that provides for the automatic derivation of many iterative and parallel control structures. The semantics repeatedly applies a “Normalize-Transpose-Distribute” operation to functions and operators until base cases are discovered. Base cases include the grounding of variables and the application of built-in operators to operands of appropriate types. This article introduces the results of a 24-month effort to reduce the language to a very small set of primitives. Included are comparisons with other languages, the formal syntax and semantics, and the traces of several example problems run with a prototype interpreter developed in 2006.

This paper highlights a 15-year research effort during which the executable specification language SequenceL has been researched and developed. The paper covers early insights into how iterative control structures are used as well as advances involving simple and general semantics

To help meet NASA's computer science research needs, the number one priority at the NASA Ames Research Center is now computer science research. NASA's change in focus has arisen out of its realization that the major technological roadblocks impeding the nation's ability to perform earth and space science, and to achieve its exploration goals, center on computation and Artificial Intelligence (AI). Communication delays on long distance missions compel NASA to focus on Computer Science research. With roundtrip communication delays ranging from 6 to 45 minutes between Earth and Mars, human and robotic missions cannot be effectively controlled remotely from earth. Much of the intelligence provided by Mission Controllers will, in the future, necessarily accompany human and virtual explorers.

SequenceL is a language that provides declarative constructs for non-scalar processing. Rather than specifying program control structures that, in turn, imply a data product, the problem solver specifies a data product, and the control structures to produce or process the data product are implied. Although SequenceL has been previously introduced in two papers (Cooke, DE. An Introduction to SequenceL: A language to experiment with constructs for processing nonscalars. Software—Practice and Experience 1996; 26(11):1205–1246; and Cooke, D. SequenceL Provides a Different way to View Programming. Computer Languages 1998; 24:1–32), recent improvements to the language have indicated that parallel control structures are also implied by the SequenceL problem solutions. This paper focuses on these recent advances. Copyright © 2000 John Wiley & Sons, Ltd.

This paper introduces a new computational model for SequenceL. The model is extended through the addition of a notion of the VRAM model. The computational model introduced together with the SequenceL language provides for a good expression of distributed behaviour.

SequenceL is a language intended for experimentation with declarative constructs for nonscalar processing. In SequenceL, a problem solver provides little in the way of iterative/recursive details in a problem solution. Instead, the problem solver describes the solution directly by specifying, via a metastructure, the data structures which will hold results useful for solving the problem. SequenceL is a small language (i.e. there is a small number of language constructs), and it is not domain dependent. This paper is meant to introduce the reader to SequenceL.

This paper explores the possibility of automated support for detecting inconsistencies in software systems and requirements. The inconsistencies are introduced when the environment of the software system changes. We refer to the software environment as its context. We review the recent research progress on nonmonotonic logics, pointing out the significance of these results to software maintenance. We explain how a practical implementation of such logics can be obtained via a simple extension to logic programming in the form of an answer procedure that realizes the Extended Logic Semantics [7] for nonmonotonic logic programs that have a unique answer set (which is a large and useful class of logic programs). We augment the existing automated capabilities of the Computer-Aided Prototyping System (CAPS) for rapid prototyping via the extension to logic programming to provide an improved automated capability for detecting certain kinds of inconsistencies created by implicit requirements changes. We illustrate the significance of this capability via an example prototype for a problem originally suggested by Lehman.

In this paper we combine a variation of the CAPS model with an extended version of Prolog based upon the stable model semantics of logic programming [GEL]. We believe this to be the first paper presenting such a combination. In order to combine the CAPS model with the extended Prolog, we first implement a subset of the PSDL language in Prolog. We show the significance of the combination through an example prototype of a problem originally suggested by Lehman (1990). The resulting model provides a general framework for developing prototypes capable of determining when they are in need of adaptive maintenance.>

This paper reviews the impact that the next generation programming environment may have on the software process model. In doing so it informally defines the concept of a next generation language and seriously considers the concerns of software development, validation, verification, and evolution within the context of a future abstraction.

There are at least two different kinds of uncertainty in software development. Both are centered around software specification. The first type has to do with the uncertainty as to whether or not a given description is truly a specification of the software to be developed. The second type of uncertainty has to do with the lifetime of a valid specification. Most programs have parts that are a mixture of the two types. A high-level view of both types of uncertainty in specification is presented to explain the problems inherent in software development and maintenance. The view supports the need for prototyping throughout software development and maintenance.>

If a well-structured concurrent program is represented as a Petri net, it is possible to analyze the network for deadlock. By well-structured concurrent program is meant one in which levels of nesting follow structured programming tenets. Program liveness is defined for a well-structured concurrent program represented as a Pefri net, a Prolog program which will analyze the Petri net for deadlock is presented, and it is proved that the program truly implements the specification of program liveness.>

Introduces a compilable program specification language, BagL. BagL is the result of a formal study to ascertain how data/control structure interaction can be abstracted. BagL meets the accepted properties of a 'good' language. BagL maintains a consistent level of abstraction; is extensible, orthogonal, concise, and unambiguous; and addresses software evolutionary issues. A visual interface for the formal BagL language is presented, as well as the syntax and informal semantics of BagL.>

In this panel session, the following topics are discussed: artificial intelligence in business; artificial intelligence in multimedia; neural networks as a tool for artificial intelligence: software engineering for knowledge-based systems: and artificial intelligence as a solution for software engineering.>

Exploration is made of how methods of truth maintenance may be applied in the engineering of integrated, dynamic systems. In the life of a large system, it is not possible to foresee every significant event which may affect the behavior of the system. Truth maintenance techniques may prove useful in the production and maintenance of these large systems. A discussion is presented of how it is the decision making aspects of a system which change. Both the information on which the authors base their decisions and strategies for decision making change. Truth maintenance is discussed with respect to preserving the models of specifications and the models of programs.>

This paper reviews the progress that has been made towards the definition of a new generation of computer assisted problem solving tool. When we solve problems with a computer we state the solution in terms of several languages, beginning with a requirements specification language and ending with a program. Beginning with a generalization of a programming language, this paper follows steps towards the removal of control and data structure information in a problem solution. The effort discussed here would result in the requirements specification language being the final language used in problem solving.

A weak specification method important to the area of computer-aided software engineering (CASE) is introduced. The specification language introduced does not require the specification of control flow information. When given a specification consisting of a formula characterizing input constraints of a function and a formula characterizing output constraints, it is possible to synthesize program functions. The synthesis algorithm is guaranteed to find all functions which satisfy the specification. It is shown that when the algorithm is applied to the specifications, it is capable of producing all program structures, including sequences, selections, and iterations. Therefore, the methodology provides for a formal foundation upon which a CASE programmer assistant tool can be built.>