formal aspects of and development environments for montages

The specification of all aspects of a programming language requires adequate formal models and tool support. Montages specifications combine graphical and textual elements to yield language descriptions similar in structure, length, and complexity to those in common language manuals, but with a formal semantics. A broad range of people involved in programming language design and use may find it convenient to use Montages in combination with the tool GEM-MEX. It allows the automatic generation of high-quality documents, type-checkers, interpreters and symbolic debuggers

Numerical Implementation of the QuEST Function

This paper deals with certain estimation problems involving the covariance matrix in large dimensions. Due to the breakdown of finite-dimensional asymptotic theory when the dimension is not negligible with respect to the sample size, it is necessary to resort to an alternative framework known as large-dimensional asymptotics. Recently, Ledoit and Wolf (2015) have proposed an estimator of the eigenvalues of the population covariance matrix that is consistent according to a mean-square criterion under large-dimensional asymptotics. It requires numerical inversion of a multivariate nonrandom function which they call the QuEST function. The present paper explains how to numerically implement the QuEST function in practice through a series of six successive steps. It also provides an algorithm to compute the Jacobian analytically, which is necessary for numerical inversion by a nonlinear optimizer. Monte Carlo simulations document the effectiveness of the code.Comment: 35 pages, 8 figure

A framework for compositional verification of security protocols

Automatic security protocol analysis is currently feasible only for small protocols. Since larger protocols quite often are composed of many small protocols, compositional analysis is an attractive, but non-trivial approach. We have developed a framework for compositional analysis of a large class of security protocols. The framework is intended to facilitate automatic as well as manual verification of large structured security protocols. Our approach is to verify properties of component protocols in a multi-protocol environment, then deduce properties about the composed protocol. To reduce the complexity of multi-protocol verification, we introduce a notion of protocol independence and prove a number of theorems that enable analysis of independent component protocols in isolation. To illustrate the applicability of our framework to real-world protocols, we study a key establishment sequence in WiMAX consisting of three subprotocols. Except for a small amount of trivial reasoning, the analysis is done using automatic tools

Xasm - An Extensible, Component-Based Abstract State Machines Language

State Machines Language Matthias Anlau GMD FIRST, Kekulestr. 7 D-12489 Berlin, Germany [email protected] Abstract. The Abstract State Machine (ASM) [15] approach has already proven to be suitable for large-scale specications of realistic systems [9, 8, 18, 20]. Due to the fact that the ASM approach denes a notion of executing specications, it provides a perfect basis for a language, which can be used as a specication language as well as a high-level programming language. However, in order to upgrade to a realistic programming language, such a language must { besides other features { add a modularization concept to the core ASM constructs in order to provide the possibility to structure large-scale ASM-formalizations and to exibly dene reusable specication units. In this paper, the language Xasm, which stands for Extensible ASM, is presented. Xasm realizes a component-based modularization concept based on the notion of external functions as dened in ASMs. This p..

Contents

Pda is a graphical editor and support tool for deriving protocols. This document is under construction; some sections are incomplete, others are entirely missing, or in a very early construction phase. Partly this reflects the reality of a rapidly changing interface. Please do not hesitate to contact us to identify problems or inquire about unclear or incomplet