The past few years have witnessed unprecedented growth of the Internet. Several new service models have been introduced since. In particular, the advent of the IP multicast technology has contributed to the success of the Internet as a medium for wide-area group communication. Multicast protocols support an important class of applications ranging from multimedia conferencing to network games. Due to this growth, the degree of heterogeneity of the network components has radically increased, leading to added complexity in the design and testing of network protocols. In the presence of network failures, unexpected combinations of events can drive protocols into undesirable states and may lead to errors. Anticipating all such cases is often impossible and at best may require extensive simulation and testing. In large systems, the cost of testing all possible scenarios exhaustively is prohibitive, and many unexpected cases are not observed until deployment. This problem is even more complex...

This paper generalizes the concept of Mazurkiewicz traces to a fuzzy description of a concurrent process, where a known prefix is given in a first component and a second alphabetic component yields necessary information about future actions. This allows to define a good semantic domain where the concatenation is continuous with respect to the Scott- and to the Lawson topology. For this we define the notion of ff\Gamma and of ffi -trace. We show various mathematical results proving thereby the soundness of our approach. Our theory is a proper generalization of the theory of finite and infinite words (with explicit termination) and of the theory of finite and infinite (real and complex) traces. We make use of trace theory, domain theory, and topology. 1 Introduction The theory of Mazurkiewicz traces has been recognized as an important tool for investigating concurrent systems, overviews are in [Maz87, AR88, Per89, Die90, DR95]. The underlying idea is that for a given alphabet...

The field of theoretical computer science has had a long tradition of providing wonderful edited books to honor various prominent members of the community. The idea behind such edited works is clear: celebrate the work of a particular researcher by having co-authors and colleagues write papers on subjects related to the researcher’s body of work. When successful, such a project provides for a wonderful excursion through the work of a researcher, often highlighting an underlying coherence to that work. On that account, the book “Proof, Language, and Interaction: Essays in the Honour of Robin Milner ” (edited by Plotkin, Stirling and Tofte) is a success. In no small part this is due to Milner’s span of work from theory to practice. It is hard to both briefly describe Milner’s contributions and give an idea of the breadth of his effort. Two major tracks of research emerge. First, after some work with John McCarthy’s AI group at Stanford, he developed LCF (specifically, Edinburgh LCF), a system for computer-assisted theorem proving based on Dana Scott’s ideas on continuous partial functions for denotational semantics. Not only working on the implementation, Milner also worried about the semantic foundations [1]. LCF came with a programming language, Edinburgh ML, which evolved with Milner’s help into Standard ML, a higher-order language that introduced many features now standard in advanced programming language, features such as polymorphism and type inference [4]. His second track of research involves concurrency. He invented CCS, the calculus of communicating systems [2]. Work on the semantics of CCS went

nvolves concurrency. He invented CCS, the calculus of communicating systems [2]. Work on the semantics of CCS went from the traditional domain-theoretic approach to a new operational view of processes equality based on the notion of bisimulation. Subsequent work by Milner led to the development of other calculi, most notably the -calculus, which included a powerful notion of mobility [3]. His later work in the area attempted to provide a unifying framework for comparing calculi, and unifying sequential and concurrent computation. This range of interests is reflected in the table of contents of the book. The book splits across different subjects: semantic foundations, where we discover work aimed at understanding computation, both sequential and concurrent, programming logic, where we discover work derived from Milner's work on LCF, and aimed at understanding the role of formal mathematics, programming languages, where we discover St

Introduction With the rise of computer networks in the past decades, the spread of distributed applications with components across multiple machines, and with new notions such as mobile code, there has been a need for formal methods to model and reason about concurrency and mobility. The study of sequential computations has been based on notions such as Turing machines, recursive functions, the -calculus, all equivalent formalisms capturing the essence of sequential computations. Unfortunately, for concurrent programs, theories for sequential computation are not enough. Many programs are not simply programs that compute a result and return it to the user, but rather interact with other programs, and even move from machine to machine. Process calculi are an attempt at getting a formal foundation based on such ideas. They emerged from the work of Hoare [4] and Milner [6] on models of concurrency. These calculi are meant to model systems made up of processes communicating by exchanging

Introduction to Combinatorial Optimization, Randomization, Approximation, and Heuristics by Juraj Hromkovic. Reviewed by Hassan Masum. This book examines a variety of practical ways to solve NP-complete problems in practice. 3. Modal and Temporal Properties of Processes by Colin Stirling. Review by Vicky Weissman. This book is about modelling a process by modal logics. It is a good introduction to process algebras. 4. Modal Logic by Patrick Blackburn, Maarten de Rijke, and Yde Venema. Reviewd by P. Daniel Hestand. This book is a comprehensive treatement of Modal logic. It includes Completeness theorems and also a discussion of the complexity of some of the problems in the field. Books I want Reviewed If you want a FREE copy of one of these books in exchange for a review, then email me at gasarchcs.umd.edu Reviews need to be in LaTeX, LaTeX2e, or Plaintext. Books on Algorithms, Combinatorics, and Related Fields 1. Genomic Perl: From Bioinformatics Basics to Working Code by Rex Dw

call that ten years ago, the first version of Microsoft Windows was barely out the door), the available literature on the -calculus has consisted of original papers (for instance [5], [4], [7]) and PhD theses (for instance [6]). No longer. Milner's short monograph, peaking at about 160 pages, gives a well-rounded and self-contained introduction to the material. According to the Preface, the book is based on lecture notes for a final-year undergraduate course, and the material is acknowledged to be challenging. No formal prerequisites are listed, short of a working knowledge of automata theory. However, the material does require a certain level of mathematical maturity. The presentation is in two parts, splitting the book roughly in half. Part I ("Communicating systems") covers the basic material on communicating system, with a focus on the algebraic treatment of concurrency and communication. There is no mobility in this first part. It summarizes the work of Milner on CCS, explained

Abstract not found

Abstract—Code mobility technologies attract more and more developers and consumers. Numerous domains are concerned, many platforms are developed and interest applications are realized. However, developing good software products requires modeling, analyzing and proving steps. The choice of models and modeling languages is so critical on these steps. Formal tools are powerful in analyzing and proving steps. However, poorness of classical modeling language to model mobility requires proposition of new models. The objective of this paper is to provide a specific formalism “Coloured Reconfigurable Nets ” and to show how this one seems to be adequate to model different kinds of code mobility. Keywords—Code mobility, modeling mobility, labeled reconfigurable nets, Coloured reconfigurable nets, mobile code design paradigms. I.