For decades, secure operating systems have incorporated mandatory access control (MAC) techniques. Surprisingly, mobile-code platforms such as the Java Virtual Machine (JVM) and the .NET Common Language Runtime (CLR) have largely ignored these advances and have implemented a far weaker security that does not reliably track ownership and access permissions for individual data items. We have impl...

We describe the analytic center cutting plane method and its relationship to classical methods of nondi erentiable optimization and column generation. Implementation issues are also discussed, and current applications listed. Keywords Projective Algorithm, Analytic Center, Cutting Plane Method. This work has been completed with support from the Fonds National Suisse de la Recherche Scienti que,...

ion is the process of separating properties of objects into two classes, one for details that are relevant to a given task and the other for those that are not. The purpose of this process is to provide some number of partial problem-speci c views of a given object, each one simpler than the complete view because it temporarily disregards inessential details. Whether or not some property of a g...

domain. The safeness of the analysis is veri ed by formalising a correspondence between the concrete domain and the abstract domain and proving that the abstract operators safely simulate the concrete operators with respect to the correspondence [11]. One way to formalise the correspondence is by a function, called an abstraction (function), from the concrete domain to the abstract domain. We a...

ion function, generalised to allow for non-idempotent substitutions. We conclude in Section 5. 2 Equations and Substitutions 2.1 Notation For a set S, #S is the cardinality of S, }(S) is the powerset of S, whereas }f(S) is the set of all the nite subsets of S. The symbol Vars denotes a denumerable set of variables, whereas TVars denotes the set of rst-order terms over Vars for some given set of...

classes for the support of activities in C++ [Stroustrup 91]. The distinction between two important types of implementations of activities: initiating activities and reacting activities. Paper organization. In section 2 we discuss the use of activities as they apply to the modeling process. We use card games as a concrete example, and we discuss generally the fundamental characteristics of acti...

A methodology for deriving programs from speci cations of observable behaviour is described. The class of processes to which this methodology is applicable includes those whose state changes are fully de nable by labelled transition systems, for example communicating processes without internal state changes. A logic program representation of such labelled transition systems is proposed, interpr...

Planaria species are powerful models for the study of drug effects and addiction on neural and cognitive function due to their tractability to cell‐biological, pharmacological and molecular‐genetic techniques. In order to fully capitalize on the many advantages of this system, it is necessary to be able to analyze behavior and learning in a quantitative manner in worms that have been treated wi...

The formalization of abductive reasoning is still an open question: there is no general agreement on the boundary of some basic concepts, such as preference criteria for explanations, and the extension to rst order logic has not been settled. Investigating the nature of abduction outside the context of resolution based logic programming still deserves attention, in order to characterize abducti...

The problems of nding a longest common subsequence and a shortest common supersequence of a set of strings are well-known. They can be solved in polynomial time for two strings (in fact the problems are dual in this case), or for any xed number of strings, by dynamic programming. But both problems are NP-hard in general for an arbitrary number k of strings. Here we study the related problems of...