The computational power of a tree of processors is investigated. It is demonstrated that a tree of processors can solve certain problems impressively fast by exploiting the internal pipelining capabilities. Efficient ...
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ISBN:
(纸本)0818619821
The computational power of a tree of processors is investigated. It is demonstrated that a tree of processors can solve certain problems impressively fast by exploiting the internal pipelining capabilities. Efficient tree algorithms are designed for two different problems: selection and maintaining dictionaries. It is shown that an O(log n)-height tree of processors can find the kth smallest element of n numbers in deterministic O((log n)2+o(1)) steps, an impressive improvement over previous results. The main tools are the development of a new sampling technique and an elegant internal pipelining strategy. A lower bound is established for this selection problem. Another variant of the sampling technique reduces the storage requirement of R. M. Karp et al.'s (1986) tree searching algorithm while maintaining its speed. It is established that dictionary operations can be performed with a pipelined interval of O(1) and a response time of O(height of the tree), which again improves a known result and settles an open problem. This is based on being able to make the tree operate like a complete tree viewed from the root.
This article examines implications of coverage on the performance measurements of self-repairing computers. An extension is made to the Mathur Reliability Model which results in an alternative formulation of coverage....
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This article examines implications of coverage on the performance measurements of self-repairing computers. An extension is made to the Mathur Reliability Model which results in an alternative formulation of coverage. This formulation allows separate recovery probabilities to be assigned to processors which fail during active operation, and processors which fail during the dormant (spare) mode. A concise APL program based on this formulation is presented which is used for reliability modeling of Hybrid redundant configurations.
The possibility of using last-come-first-served preemptive-resume scheduling as a means of increasing computer system throughput is explored. The distribution and moments of the waiting time are derived and compared w...
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The possibility of using last-come-first-served preemptive-resume scheduling as a means of increasing computer system throughput is explored. The distribution and moments of the waiting time are derived and compared with those of a first-come-first-served queue. The queue length distribution and departure process are also considered.
A comparison is made between Modula and some other programming languages. Especially considered are concepts for modularity, synchronizing, representation of parallel activitites and I/O handling.
A comparison is made between Modula and some other programming languages. Especially considered are concepts for modularity, synchronizing, representation of parallel activitites and I/O handling.
Several languages have been developed for or applied to the problem of describing digital hardware systems. This paper points out some of the problems encountered in hardware descriptions, particularly where they are ...
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Several languages have been developed for or applied to the problem of describing digital hardware systems. This paper points out some of the problems encountered in hardware descriptions, particularly where they are distinct from concepts appearing in programming languages.
Information flow exhibited by multithreaded programs is subtle because the attacker may exploit scheduler properties when deducing secret information from publicly observable outputs. Volpano and Smith have introduced...
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ISBN:
(纸本)9783540708803
Information flow exhibited by multithreaded programs is subtle because the attacker may exploit scheduler properties when deducing secret information from publicly observable outputs. Volpano and Smith have introduced a protect command that prevents the scheduler from observing sensitive timing behavior of protected commands and therefore prevents undesired information flows. While a useful construct, protect is nonstandard and difficult to implement. This paper presents a transformation that eliminates the need for protect under cooperative scheduling. We show that both termination-insensitive and termination-sensitive security can be enforced by variants of the transformation in a language with dynamic thread creation.
Optimal algorithms for sorting on parallel CREW (concurrent read, exclusive write) and EREW (exclusive read, exclusive write) versions of the pointer machine model are presented. Intuitively, these methods can be view...
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ISBN:
(纸本)0818619821
Optimal algorithms for sorting on parallel CREW (concurrent read, exclusive write) and EREW (exclusive read, exclusive write) versions of the pointer machine model are presented. Intuitively, these methods can be viewed as being based on the use of linked lists rather than arrays (the usual parallel data structure). It is shown how to exploit the 'locality' of the approach to solve a problem with applications to database querying and logic programming (set-expression evaluation) in O(log n) time using O(n) processors.
In this paper, we propose a new component model called AECM that combines CBSD and AOSD and proposes a component definition language and an assembly definition language to improve reusability of components and aspects...
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ISBN:
(纸本)0769524656
In this paper, we propose a new component model called AECM that combines CBSD and AOSD and proposes a component definition language and an assembly definition language to improve reusability of components and aspects. In this component model, aspects are kinds of component and all component concepts are applicable to them. AECM categorizes aspects of a component to two categories: built-in or extension aspects, inter-components aspects or intracomponent aspects, and supports them in different ways. AECM supports definition of weave time and runtime aspect application rules and supports application and component reconfiguration at deployment time and during runtime.
This paper describes a system to automatically mark student programs. It is a real time examination system that provides an environment for the compilation and execution of software and then marks it according to crit...
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ISBN:
(纸本)0769524729
This paper describes a system to automatically mark student programs. It is a real time examination system that provides an environment for the compilation and execution of software and then marks it according to criteria and solutions provided by the examiner. It has been designed as a client server system supporting many simultaneous clients, with a modular structure that provides flexibility, allowing components to he added for new courses and kinds of questions without having to change the existing core structure. It is hoped that by sharing this software with others, a set of modules can he constructed to examine a range of programming questions. This report outlines the structure of the system. It is currently being evaluated in class assessments for software courses in network programming.
The first part of the paper gives a brief overview of meta-programming, in particular program generation, and its use in software development. The second part introduces a basic calculus, related to FreshML, that supp...
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ISBN:
(纸本)3540291318
The first part of the paper gives a brief overview of meta-programming, in particular program generation, and its use in software development. The second part introduces a basic calculus, related to FreshML, that supports program generation (as described through examples and a translation of MetaML into it) and programming in-the-large (this is demonstrated by a translation of CMS into it).
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