Using formal methods to support testing

Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing

How functional programming mattered

In 1989 when functional programming was still considered a niche topic, Hughes wrote a visionary paper arguing convincingly ‘why functional programming matters’. More than two decades have passed. Has functional programming really mattered? Our answer is a resounding ‘Yes!’. Functional programming is now at the forefront of a new generation of programming technologies, and enjoying increasing popularity and influence. In this paper, we review the impact of functional programming, focusing on how it has changed the way we may construct programs, the way we may verify programs, and fundamentally the way we may think about programs

Qualifications of Instruction Sequence Failures, Faults and Defects: Dormant, Effective, Detected, Temporary, and Permanent

Starting out from the survey of instruction sequence faults from [6] program faults are classified according to the conventional criteria of being dormant, effective, detected, temporary, and permanent. Being retrospectively approved is introduced as an additional qualification. For this theoretical investigation the context is simplified by contemplating instruction sequences as a theoretical model for programs, and by assuming that instruction sequences are supposed to compute total transformations on finite bit sequences of a fixed length only. The main conclusion which can be drawn from this work concerns the notion of dormancy. First of all it is noticed that the unconventional notion of a dormant failure is both plausible and amenable to a straightforward and convincing definition. The conventional notion of a dormant fault, however, is much harder to grasp and the definition of a dormant fault which is provided in the paper may be disputed. The notion of a dormant fault seems to admit no convincing intuition. All faults are defects but not the other way around. The idea of a fault exclusively depends on an instruction sequence and a specification of which it is considered to be a candidate implementation. In the presence of a design, however, in addition to faults, the notion of a deviation from design (DFD) defect arises, which constitutes a class of defects many of which are not faults. For DFD defects the notion of dormancy admits a straightforward and convincing definition

The modern landscape of managing effects for the working programmer

The management of side effects is a crucial aspect of modern programming, especially in concurrent and distributed systems. This thesis analyses different approaches for managing side effects in programming languages, specifically focusing on unrestricted side effects, monads, and algebraic effects and handlers. Unrestricted side effects, used in mainstream imperative programming languages, can make programs difficult to reason about. Monads offer a solution to this problem by describing side effects in a composable and referentially transparent way but many find them cumbersome to use. Algebraic effects and handlers can address some of the shortcomings of monads by providing a way to model effects in more modular and flexible way. The thesis discusses the advantages and disadvantages of each of these approaches and compares them based on factors such as expressiveness, safety, and constraints they place on how programs must be implemented. The thesis focuses on ZIO, a Scala library for concurrent and asynchronous programming, which revolves around a ZIO monad with three type parameters. With those three parameters ZIO can encode the majority of practically useful effects in a single monad. ZIO takes inspiration from algebraic effects, combining them with monadic effects. The library provides a range of features, such as declarative concurrency, error handling, and resource management. The thesis presents examples of using ZIO to manage side effects in practical scenarios, highlighting its strengths over other approaches. The applicability of ZIO is evaluated by implementing a server side application using ZIO, and analyzing observations from the development process

Transformational maintenance by reuse of design histories

This thesis provides theory and procedures for modifying software artifacts implemented by a formal transformation process. Installing modifications requires knowing not only what transformations were applied (a derivation history) to construct the artifact, but also why the application sequence ensures that the artifact meets its specification. The derivation history and the justification are collectively called a design history. A Design Maintenance System (DMS), when provided with a formal change called a maintenance delta, revises a design history to guide construction of a new artifact. A DMS can be used to integrate a stream of deltas into a history, providing implementations as a side effect, leading to an incremental-evolution model for software construction.We provide a broadly applicable formal model of transformation systems in which specifications are performance predicates, subsuming the functional specifications which are traditional for transformation systems. Such performance predicates provide vocabulary used in the design history to describe the effect of applying sets of transformations.A nonprocedural, performance-goal-oriented Transformation Control Language (TCL) is defined to control navigation of the design space for a transformation system. Recording the execution of a TCL metaprogram directly provides a design history.A complete classification of, and representation for, the set of possible maintenance deltas is given in terms of the inputs defined by the transformation system model. Such deltas include not only specification changes, but also changes to implementation support technologies. Delta integration procedures for revising derivation histories given functional or support technology deltas are provided, based on rearranging the order of transformations in the design space. Building on these operations, integration procedures that revise the design history for each type of delta are described. An agenda-oriented TCL execution process dovetails smoothly with the integration procedures.Our DMS is compared to a number of other maintenance systems. By using an explicit delta and verified commutativity, our DMS often reuses transformations correctly when others fail

Automated Code Generation for Industrial-Strength Systems

Model-driven engineering proposes to develop software systems by first creating an executable model of the system design and then transforming this model into an implementation. This paper discusses the design of an automatic code generation system that transforms such models into product implementations for highly reliable, industrial-strength systems. It provides insights, practical considerations, and lessons learned when developing code generators for applications that must conform to the constraints imposed by real-world, high-performance systems. Automatic code generation has played a large part in dramatically increasing both the quality and the reliability of software for these systems

Uses and applications of artificial intelligence in manufacturing

The purpose of the THESIS is to provide engineers and personnels with a overview of the concepts that underline Artificial Intelligence and Expert Systems. Artificial Intelligence is concerned with the developments of theories and techniques required to provide a computational engine with the abilities to perceive, think and act, in an intelligent manner in a complex environment. Expert system is branch of Artificial Intelligence where the methods of reasoning emulate those of human experts. Artificial Intelligence derives it\u27s power from its ability to represent complex forms of knowledge, some of it common sense, heuristic and symbolic, and the ability to apply the knowledge in searching for solutions. The Thesis will review : The components of an intelligent system, The basics of knowledge representation, Search based problem solving methods, Expert system technologies, Uses and applications of AI in various manufacturing areas like Design, Process Planning, Production Management, Energy Management, Quality Assurance, Manufacturing Simulation, Robotics, Machine Vision etc. Prime objectives of the Thesis are to understand the basic concepts underlying Artificial Intelligence and be able to identify where the technology may be applied in the field of Manufacturing Engineering

Supporting the DSL Spectrum

A language tailored to the problem domain can focus on its idioms and jargon, avoiding clumsy, overly general constructs needed to support general-purpose language. The leverage provided by DSLs over conventional programming languages is often extreme; application engineers may specify as little as 2% of the code that one would need to program the same thing in a conventional programming language! But commitment to a DSL approach can be rather expensive. It is often difficult to know when to invest in exactly how much infrastructure support for a product or product family. All of the concerns that are germane to generalpurpose programming language design and support may become important in the support of a specific DSL. At the same time, there is a wide spectrum of approaches to providing DSL support. This paper relates the various DSL design approaches to alternatives for tool support, providing a kind of “DSL tool support selection framework,” indicating where one might expect to need to invest heavily to obtain adequate support and illustrating the spectrum of tradeoffs and situations in which each is appropriate