The Interactive Electronic Technical Specification (IETS) research project provides a paperless environment for system development documentation including requirements, specifications, and design documents, with inter...
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ISBN:
(纸本)0879425768
The Interactive Electronic Technical Specification (IETS) research project provides a paperless environment for system development documentation including requirements, specifications, and design documents, with interactive hypermedia access to needed information. IETS also will provide automated requirements and system behavior. Elements and features of IETS are presented. A description is presented of the General Dynamics IETS approach, and its future role in advanced maintenance and diagnostic systems development.
The problem of sorting a collection of values on a mesh-connected, distributed-memory, SIMD (single-instruction-stream, multiple-data-stream) computer using variants of Batcher's bitonic sort algorithm is consider...
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ISBN:
(纸本)0818620536
The problem of sorting a collection of values on a mesh-connected, distributed-memory, SIMD (single-instruction-stream, multiple-data-stream) computer using variants of Batcher's bitonic sort algorithm is considered for the case in which the number of values exceeds the number of processors in the machine. In this setting the number of comparisons can be reduced asymptotically if the processors have addressing autonomy (locally indirect addressing), and communication costs can be reduced by judicious domain decomposition. The implementation of several related adaptations of bitonic sort on a MasPar MP-1 is reported. Performance is analyzed in relation to the virtualization ratio VPR. It is concluded that the most reasonable large-array sort for this machine will combine hypercube virtualization with the processor axes transposed dynamically within an xnet embedding.
In distributed programs, we usually keep some global predicates from being satisfied to make it easy to run the programs correctly. A common type of global predicates are: the total number of certain tokens in the who...
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ISBN:
(纸本)0818682272
In distributed programs, we usually keep some global predicates from being satisfied to make it easy to run the programs correctly. A common type of global predicates are: the total number of certain tokens in the whole distributed system is always the same or in specific ranges, In this paper;we call this summative predicates, classified into the following four: (1) at some global state of the system, N not equal K, (2) N < K (or N less than or equal to K), (3) N > K (or N greater than or equal to K), and (4) N = K, where N is the fetal number of tokens and ii is a constant. This paper investigates the methods of detecting various summative global predicates, The first class of summative predicates are trivial to detect by simply checking each message, For the second class of summative predicates, Groselj [6] and Garg [2] solved the problem by reducing the problem to a maximum network pou: problem. In this paper, we propose an elegant technique, called normalization, to allow the second and third classes of summative predicates to be solved by also reducing the problem to a maximum network pou: problem. For the fourth floss of summative! predicates, we prove that it is an NP-complete problem.
A tool, called LOCALIZER, which improves the locality of programs for multiprogrammed virtual-memory computersystems, is described. The method of critical working sets, which is the basis of the tool, is presented. T...
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A tool, called LOCALIZER, which improves the locality of programs for multiprogrammed virtual-memory computersystems, is described. The method of critical working sets, which is the basis of the tool, is presented. This method is especially suitable for those systems where primary memory is managed according to the working set strategy. The various modules of the tool are briefly described after a discussion of the general restructuring procedure.
We propose a bounded model checking procedure for programs manipulating dynamically allocated pointer structures. Our procedure checks whether a program execution of length n ends in an error (e. g., a NULL dereferenc...
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ISBN:
(纸本)3540282319
We propose a bounded model checking procedure for programs manipulating dynamically allocated pointer structures. Our procedure checks whether a program execution of length n ends in an error (e. g., a NULL dereference) by testing if the weakest precondition of the error condition together with the initial condition of the program (e. g., program variable x points to a circular list) is satisfiable. We express error conditions as formulas in the 2-variable fragment of the Bernays-Schonfinkel class with equality. We show that this fragment is closed under computing weakest preconditions. We express the initial conditions by unary relations which are defined by monadic Datalog programs. Our main contribution is a small model theorem for the 2-variable fragment of the Bernays-Schonfinkel class extended with least fixed points expressible by certain monadic Datalog programs. The decidability of this extension of first-order logic gives us a bounded model checking procedure for programs manipulating dynamically allocated pointer structures. In contrast to SAT-based bounded model checking, we do not bound the size of the heap a priori, but allow for pointer structures of arbitrary size. Thus, we are doing bounded model checking of infinite state transition systems.
Combinatorial Chemistry is a powerful new technology in drug design and molecular recognition. It is a wet-laboratory methodology aimed at "massively parallel" screening of chemical compounds for the discove...
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ISBN:
(纸本)0898714532
Combinatorial Chemistry is a powerful new technology in drug design and molecular recognition. It is a wet-laboratory methodology aimed at "massively parallel" screening of chemical compounds for the discovery of compounds that have a certain biological activity. The power of the method comes from the interaction between experimental design and computational modeling. Principles of "rational'' drug design are used in the construction of combinatorial libraries to speed up the discovery of lead compounds with the desired biological activity. This paper presents algorithms, software development and computational complexity analysis for problems arising in the design of combinatorial libraries for drug discovery. We provide exact polynomial time algorithms and intractability results for several Inverse Problems - formulated as (chemical) graph reconstruction problems - related to the design of combinatorial libraries. These are the first rigorous algorithmic results in the literature. We also present results provided by our combinatorial chemistry software package OCOTILLO for combinatorial peptide design using real data libraries. The package provides exact solutions for general inverse problems based on shortest-path topological indices. Our results are superior both in accuracy and computing time to the best software reports published in the literature. For 5-peptoid design, the computation is rigorously reduced to an exahustive search of about 2% of the search space;the exact solutions are found in a few minutes.
In this paper we propose a dynamic code overlay technique of synchronous data-flow (SDF) -modeled program for low-end embedded systems which lack MMU-support. With this technique, the system can utilize expensive SRAM...
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ISBN:
(纸本)9783981080117
In this paper we propose a dynamic code overlay technique of synchronous data-flow (SDF) -modeled program for low-end embedded systems which lack MMU-support. With this technique, the system can utilize expensive SRAM memory more efficiently by using flash memory as code storage. SRAM is divided into several regions called overlay slots. A data-flow block or a cluster of data-flow blocks is loaded into the corresponding overlay slot on demand at run-time. Which blocks are clustered together and which overlay slots are allocated to the clusters are statically decided by the clustering and placement algorithm. We also propose an automatic code generation framework that generates the C-prograin code, dynamic loader and linker script files from the given SDF-modeled blocks and schematic, so we can run or simulate the program immediately without any additional coding effort. Experiments report that we can reduce the SRAM size significantly with a reasonable amount of time overhead for several real applications.
A description is given of the KRTM kernel which has been designed in order to facilitiate real-time multiprogramming during the development of TELEX-M, a dedicated operating system for telex exchanges. KRTM creates a ...
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A description is given of the KRTM kernel which has been designed in order to facilitiate real-time multiprogramming during the development of TELEX-M, a dedicated operating system for telex exchanges. KRTM creates a run-time environment supporting execution of all the operating system programs. Although the KRTM characteristics have been derived from the very concrete real life program (to design and implement a reliable operating system capable to provide a satisfactory service for 512 telex abonents and trunks to other switching systems), the resulting product seems to be more general, covering a wider class of strongly multiprogramed, real-time minicomputersystems with high reliability and modularity requirements. The KRTM itself has been designed with the requirement for modifiability in mind, and therefore it is easy to obtain new versions of the kernel, adapted to a particular application.
An attempt is made to clarify certain generally-accepted beliefs regarding software, such as: software represents a growing proportion of total data processing expenditure;and software outlasts hardware.
An attempt is made to clarify certain generally-accepted beliefs regarding software, such as: software represents a growing proportion of total data processing expenditure;and software outlasts hardware.
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