Hanne Riis Nielson – författare

The authors describe here a framework in which the type notation of functional languages is extended to include a notation for binding times (that is run-time and compile-time) that distinguishes between them. Consequently the ability to specify code and verify program correctness can be improved. Two developments are needed, the first of which introduces the binding time distinction into the lambda calculus, in a manner analogous with the introduction of types into the untyped lambda calculus. Methods are also presented for introducing combinators for run-time. The second concerns the interpretation of the resulting language, which is known as the mixed lambda-calculus and combinatory logic. The notion of 'parametrized semantics' is used to describe code generation and abstract interpretation. The code generation is for a simple abstract machine designed for the purpose; it is close to the categorical abstract machine. The abstract interpretation focuses on a strictness analysis that generalises Wadler's analysis for lists.

The authors describe here a framework in which the type notation of functional languages is extended to include a notation for binding times (that is run-time and compile-time) that distinguishes between them. Consequently the ability to specify code and verify program correctness can be improved. Two developments are needed, the first of which introduces the binding time distinction into the lambda calculus, in a manner analogous with the introduction of types into the untyped lambda calculus. Methods are also presented for introducing combinators for run-time. The second concerns the interpretation of the resulting language, which is known as the mixed lambda-calculus and combinatory logic. The notion of 'parametrized semantics' is used to describe code generation and abstract interpretation. The code generation is for a simple abstract machine designed for the purpose; it is close to the categorical abstract machine. The abstract interpretation focuses on a strictness analysis that generalises Wadler's analysis for lists.

Semantics will have an important role to play in the future development of software systems and domain specific languages, and there is a real need for an introductory book that presents the fundamental ideas behind these approaches; stresses their relationship by formulating and proving the relevant theorems; and illustrates the applications of semantics in computer science. This book investigates the relationship between the various methods and describes some of the main ideas used, illustrating these via interesting applications. Historically important application areas are used together with some exciting potential applications including: Validating prototype implementations of programming languages. Verifying program analyses that are part of more advanced implementations of programming languages. Verifying security analyses. Verifying useful program properties including information about execution time.

This textbook is an introduction to the use of formal methods ranging from semantics of key programming constructs to techniques for the analysis and verification of programs. The authors use program graphs as the mechanism for representing the control structure of programs in order to find a balance between generality and conceptual complexity.The early chapters on program graphs and the Guarded Commands language are sufficient introduction for most readers to then enjoy a plug-and-play approach to the remaining chapters. These explain formal methods for analysing the behaviour of programs in various ways ranging from verification, via program analysis and language-based security, to model checking. The remaining chapters present language extensions with procedures and concurrency and cover their semantics.The book is suitable for advanced undergraduate and graduate courses in software development, and the text is supported throughout with exercises of varying grades of difficulty. The authors have developed an online learning environment that allows students to create examples beyond those covered in the main text, and in the book appendices they present programming projects aimed at implementing central parts of the development using the functional language F#.

This book constitutes the proceedings of the 21th International Conference on Coordination Models and Languages, COORDINATION 2019, held in Kongens Lyngby, Denmark, in June 2019, as part of the 14th International Federated Conference on Distributed Computing Techniques, DisCoTec 2019.The 15 full papers included in this volume were carefully reviewed and selected from 25 submissions. The papers are organized in topical sections named: computational models; tools; exploring new frontiers; and coordination patterns.

This volume, the 7th in the Transactions on Computational Systems Biology series, contains a fully refereed and carefully selected set of papers from two workshops: BioConcur 2004 held in London, UK in August 2004 and BioConcur 2005 held in San Francisco, CA, USA in August 2005. The 8 papers chosen for this special issue are devoted to various aspects of computational methods, algorithms, and techniques in bioinformatics.

The aim of static analysis is to develop principles, techniques and tools for validatingpropertiesofprograms,fordesigningsemantics-basedtransformations of programs and for obtaining high-performance implementations of high-level programming languages. Over the years the series of static analysis symposia has served as the primary venue for presentation and discussion of theoretical, practical and innovative advances in the area. This volume contains the papers accepted for presentation at the 14th Int- national Static Analysis Symposium (SAS 2007). The meeting was held August, 22–24, 2007, at the Technical University of Denmark (DTU) in Kongens L- gby, Denmark. In response to the call for papers, 85 submissions were received. Each submission was reviewed by at least 3 experts and, based on these reports, 26 papers were selected after a week of intense electronic discussion using the EasyChair conference system. In addition to these 26 papers, this volume also containscontributionsbythetwoinvitedspeakers:FrankTip(IBMT.J.Watson Research Center, USA) and Alan Mycroft (Cambridge University, UK). On the behalf of the Program Committee, the Program Chairs would like to thank all the authors who submitted their work to the conference and also all the external referees who have been indispensable for the selection process. Special thanks go to TerkelTolstrup and J¨ org Bauer,who helped in handing the submitted papers and in organizing the structure of this volume. We would also like to thank the members of the Organizing Committee at DTU for their great work. Finally we want to thank the PhD school ITMAN at DTU for ?nancial support.