Distributed authorization is an essential issue in computer security. Recent research shows that trust management is a promising approach for the authorization in distributed environments. There are two key issues for...
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Distributed authorization is an essential issue in computer security. Recent research shows that trust management is a promising approach for the authorization in distributed environments. There are two key issues for a trust management system: how to design an expressive high-level policy language and how to solve the compliance-checking problem (Blaze et al. in proceedings of the Symposium on Security and Privacy, pp. 164-173, 1996;proceedings of 2nd International conference on Financial Cryptography (FC'98). LNCS, vol.1465,pp.254-274, 1998), where ordinary logic programming has been used to formalize various distributed authorization policies (Li et al. in proceedings of the 2002 IEEE Symposium on Security and Privacy, pp. 114-130, 2002;acm Trans. Inf. Syst. Secur. (TISSEC) 6(1): 128-171, 2003). In this paper, we employ Answer Set programming to deal with many complex issues associated with the distributed authorization along the trust management approach. In particular, we propose a formal authorization language AL providing its semantics through Answer Set programming. Using language AL, we cannot only express nonmonotonic delegation policies which have not been considered in previous approaches, but also represent the delegation with depth, separation of duty, and positive and negative authorizations. We also investigate basic computational properties related to our approach. Through two case studies. we further illustrate the application of our approach in distributed environments.
Multiple dispatch - the selection of a function to be invoked based on the dynamic type of two or more arguments - is a solution to several classical problems in object-oriented programming. Open multi-methods general...
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The emergence of standards for programming real-time systems in Java has encouraged many developers to consider its use for systems previously only built using C, Ada, or assembly language. However, the RTSJ standard ...
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ISBN:
(纸本)9781595938251
The emergence of standards for programming real-time systems in Java has encouraged many developers to consider its use for systems previously only built using C, Ada, or assembly language. However, the RTSJ standard in isolation leaves many important problems unaddressed, and suffers from some serious problems in usability and safety. As a result, the use of Java for real-time programming has continued to be viewed as risky and adoption has been slow. In this paper we provide a description of IBM's new real-time Java virtual machine product, which combines Metronome real-time garbage collection, ahead-of-time compilation, and a complete implementation of the RTSJ standard, running on top of a custom real-time multiprocessor Linux kernel. We will describe the implementation of each of these components, including how they interacted both positively and negatively, and the extensions to previous work required to move it from research prototype to a system implementing the complete semantics of the Java language. The system has been adopted for hard real-time development of naval weapons systems and soft real-time telecommunications servers. We present measurements showing that the system is able to provide sub-millisecond worst-case garbage collection latencies, 50 microsecond Linux scheduling accuracy, and eliminate non-determinism due to JIT compilation. Copyright 2007 acm.
Problem solving by declarative theory building can be an extremely effective method for porting concepts and knowledge from the problem domain to the solution domain, by allowing the implementation of complete procedu...
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ISBN:
(纸本)9789728865894
Problem solving by declarative theory building can be an extremely effective method for porting concepts and knowledge from the problem domain to the solution domain, by allowing the implementation of complete procedural constructs and enabling to produce sound solutions. If conveniently expressed, such a theory may be directly coded into a declarative programminglanguage. If expressed within the paradigm of logic programming, then the theory itself represents the very procedure to obtain its desired solutions. The illustrative case study considered here is the obtention of architectural layouts from an adjacency graph: Given a list of imposed adjacencies among a set of planar rectangular spaces (represented by the graph's nodes), the goal is to generate all permissible layouts schemas on the plane which respect the adjacencies, and to determine the minimal modular dimensions of such a set of spaces. Another aim of this article is also to show the guidelines of an effective translation of the theory constructed to solve the proposed problem in Logic programming, making use of the combined power of two different semantics and their implementations, namely the Well Founded Semantics and the Stable Models one.
Stream architecture is a novel microprocessor architecture with wide application potential. But as for whether it can be used efficiently in scientific computing, many issues await further study. This paper first give...
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ISBN:
(纸本)9781595937063
Stream architecture is a novel microprocessor architecture with wide application potential. But as for whether it can be used efficiently in scientific computing, many issues await further study. This paper first gives the design and implementation of a 64-bit stream processor, FT64 (Fei Teng 64), for scientific computing. The carrying out of 64-bit extension design and scientific computing oriented optimization are described in such aspects as instruction set architecture, stream controller, micro controller, ALU cluster, memory hierarchy and interconnection interface here. Second, two kinds of communications as message passing and stream communications are put forward. An interconnection based on the communications is designed for FT64-based high performance computers. Third, a novel stream programminglanguage, SF95 (Stream FORTRAN95), and its compiler, SF95Compiler (Stream FORTRAN95 Compiler), are developed to facilitate the development of scientific applications. Finally, nine typical scientific application kernels are tested and the results show the efficiency of stream architecture for scientific computing.
The proceedings contain 29 papers. The topic discussed include: a serializability violation detector for shared-memory server programs;path slicing;checking type safety of foreign function calls;permission-based owner...
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The proceedings contain 29 papers. The topic discussed include: a serializability violation detector for shared-memory server programs;path slicing;checking type safety of foreign function calls;permission-based ownership: encapsulating state in higher-order typed languages;code placement for improving dynamic branch prediction accuracy;garbage collection without paging;register allocation for software pipelined multi-dimensional loops;automatically partitioning packet processing applications for pipelined architectures;programming ad-hoc networks of mobile and resource-constrained devices;composing security policies with polymer;and formal loop merging for signal transforms.
We present a novel technique for static race detection in Java programs, comprised of a series of stages that employ a combination of static analyses to successively reduce the pairs of memory accesses potentially inv...
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Atomos is the first programminglanguage with implicit transactions, strong atomicity, and a scalable multiprocessor implementation. Atomos is derived from Java, but replaces its synchronization and conditional wailin...
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Program termination is central to the process of ensuring that systems code can always react. We describe a new program termination prover that performs a path-sensitive and context-sensitive program analysis and prov...
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