Formal language

About: Formal language is a research topic. Over the lifetime, 5763 publications have been published within this topic receiving 154114 citations.

Role-based authorization constraints specification

Abstract: Constraints are an important aspect of role-based access control (RBAC) and are often regarded as one of the principal motivations behind RBAC. Although the importance of contraints in RBAC has been recogni zed for a long time, they have not recieved much attention. In this article, we introduce an intuitive formal language for specifying role-based authorization constraints named RCL 2000 including its basic elements, syntax, and semantics. We give soundness and completeness proofs for RCL 2000 relative to a restricted form of first-order predicate logic. Also, we show how previously identified role-based authorization constraints such as separtation of duty (SOD) can be expressed in our language. Moreover, we show there are other significant SOD properties that have not been previously identified in the literature. Our work shows that there are many alternate formulations of even the simplest SOD properties, with varying degree of flexibility and assurance. Our language provides us a rigorous foundation for systematic study of role-based authorization constraints.

Introduction to Formal Languages and Automata

Abstract: Formal languages, automata, computability, and related matters form the major part of the theory of computation. This textbook is designed for an introductory course for computer science and computer engineering majors who have knowledge of some higher-level programming language, the fundamentals of

Two-dimensional languages

Abstract: The aim of this chapter is to generalize concepts and techniques of formal language theory to two dimensions. Informally, a two-dimensional string is called a picture and is defined as a rectangular array of symbols taken from a finite alphabet. A two-dimensional language (or picture language) is a set of pictures.

Formal verification of probabilistic systems

Abstract: This dissertation presents methods for the formal modeling and specification of probabilistic systems, and algorithms for the automated verification of these systems. Our system models describe the behavior of a system in terms of probability, nondeterminism, fairness and time. The formal specification languages we consider are based on extensions of branching-time temporal logics, and enable the expression of single-event and long-run average system properties. This latter class of properties, not expressible with previous formal languages, includes most of the performance properties studied in the field of performance evaluation, such as system throughput and average response time. Our choice of system models and specification languages has been guided by the goal of providing efficient verification algorithms. The algorithms rely on the theory of Markov decision processes, and exploit a connection between the graph-theoretical and probabilistic properties of these processes. This connection also leads to new results about classical problems, such as an extension to the solvable cases of the stochastic shortest path problem, an improved algorithm for the computation of reachability probabilities, and new results on the average reward problem for semi-Markov decision processes.

BLOG: Probabilistic Models with Unknown Objects

Abstract: We introduce BLOG, a formal language for defining probability models with unknown objects and identity uncertainty. A BLOG model describes a generative process in which some steps add objects to the world, and others determine attributes and relations on these objects. Subject to certain acyclicity constraints, a BLOG model specifies a unique probability distribution over first-order model structures that can contain varying and unbounded numbers of objects. Furthermore, inference algorithms exist for a large class of BLOG models.