ATOS: Integration of advanced technology software within distributed Spacecraft Mission Operations Systems

The Advanced Technology Operations System (ATOS) is a program of studies into the integration of advanced applications (including knowledge based systems (KBS)) with ground systems for the support of spacecraft mission operations

ATOS-1 study Advanced technology operations system; system architecture and database concept

Work carried out under contract for the European Space AgencySIGLEAvailable from British Library Document Supply Centre- DSC:3425.9293(ESA-CR(X)--3893) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Time Granularities and Ultimately Periodic Automata

The relevance of the problem of managing periodic phenomena is widely recognized in the area of knowledge representation and reasoning. One of the most effective attempts at dealing with this problem has been the addition of a notion of time granularity to knowledge representation systems. Different formalizations of such a notion have been proposed in the literature, following algebraic, logical, string-based, and automaton-based approaches. In this paper, we focus our attention on the automaton-based one, which allows one to represent a large class of granularities in a compact and suitable to algorithmic manipulation form. We further develop such an approach to make it possible to deal with (possibly infinite) sets of granularities instead of single ones. We define a new class of automata, called Ultimately Periodic Automata, we give a characterization of their expressiveness, and we show how they can be used to encode and to solve a number of fundamental problems, such as the membership problem, the equivalence problem, and the problem of granularity comparison. Moreover, we give an example of their application to a concrete problem taken from clinical medicine

Time Granularities and Ultimately Periodic Automata

none3The relevance of the problem of managing periodic phenomena is widely recognized in the area of knowledge representation and reasoning. One of the most effective attempts at dealing with this problem has been the addition of a notion of time granularity to knowledge representation systems. Different formalizations of such a notion have been proposed in the literature, following algebraic, logical, string-based, and automaton-based approaches. In this paper, we focus our attention on the automaton-based one, which allows one to represent a large class of granularities in a compact and suitable to algorithmic manipulation form. We further develop such an approach to make it possible to deal with (possibly infinite) sets of granularities instead of single ones. We define a new class of automata, called Ultimately Periodic Automata, we give a characterization of their expressiveness, and we show how they can be used to encode and to solve a number of fundamental problems, such as the membership problem, the equivalence problem, and the problem of granularity comparison. Moreover, we give an example of their application to a concrete problem taken from clinical medicine.noneDavide Bresolin; Angelo Montanari; Gabriele PuppisBresolin, Davide; Angelo, Montanari; Gabriele, Puppi

X-GTRBAC: An XML-based policy specification framework and architecture for enterprise-wide access control

Modern day enterprises exhibit a growing trend toward adoption of enterprise computing services for efficient resource utilization, scalability, and flexibility. These environments are characterized by heterogeneous, distributed computing systems exchanging enormous volumes of time-critical data with varying levels of access control in a dynamic business environment. The enterprises are thus faced with significant challenges as they endeavor to achieve their primary goals, and simultaneously ensure enterprise-wide secure interoperation among the various collaborating entities. Key among these challenges are providing effective mechanism for enforcement of enterprise policy across distributed domains, ensuring secure content-based access to enterprise resources at all user levels, and allowing the specification of temporal and nontemporal context conditions to support fine-grained dynamic access control. In this paper, we investigate these challenges, and present X-GTRBAC, an XML-based GTRBAC policy specification language and its implementation for enforcing enterprise-wide access control. Our specification language is based on the GTRBAC model that incorporates the content- and context-aware dynamic access control requirements of an enterprise. An X-GTRBAC system has been implemented as a Java application. We discuss the salient features of the specification language, and present the software architecture of our system. A comprehensive example is included to discuss and motivate the applicability of the X-GTRBAC framework to a generic enterprise environment. An application level interface for implementing the policy in the X-GTRBAC system is also provided to consolidate the ideas presented in the paper. © 2005 ACM

On unitary convex decompositions of vectors in a JB∗JB^{*}-algebra

summary:By exploiting his recent results, the author further investigates the extent to which variation in the coefficients of a unitary convex decomposition of a vector in a unital $JB^{*}$-algebra permits the vector decomposable as convex combination of fewer unitaries; certain $C^{*}$-algebra results due to M. Rørdam have been extended to the general setting of $JB^{*}$-algebras