Generating permutations satisfying a U-D sequence, or having a given number of runs are shown to be restricted permutation problems which can be reduced to topological sorting. Algorithms for generating the solution s...
详细信息
Generating permutations satisfying a U-D sequence, or having a given number of runs are shown to be restricted permutation problems which can be reduced to topological sorting. Algorithms for generating the solution sets of such problems are outlined.
In this paper, we describe ASPEN, a concurrent stream processing environment. ASPEN is novel in that it provides a programming model in which programmers use simple annotations to exploit varying degrees and types of ...
详细信息
In this paper, we describe ASPEN, a concurrent stream processing environment. ASPEN is novel in that it provides a programming model in which programmers use simple annotations to exploit varying degrees and types of concurrency. The degree of concurrency to be exploited is not fixed by the program specification or by the underlying system. Increasing or decreasing the degree of concurrency to be exploited during execution does not require rewriting the entire program, but rather, simply reannotating it. Examples are given to illustrate the varying types of concurrency inherent in programs written within the stream processing paradigm. We show how programs may be annotated to exploit these varying degrees of concurrency. We briefly describe our implementation of ASPEN.
This study is an empirical investigation of 11th graders at a German high school (Gymnasium). Working over a 24-hour period in a computer lab, we investigated students' use of quadratic functions with 'Derive&...
详细信息
This study is an empirical investigation of 11th graders at a German high school (Gymnasium). Working over a 24-hour period in a computer lab, we investigated students' use of quadratic functions with 'Derive', and trigonometric functions with 'Mathplus'1 (or 'Theorist' for Macintosh). We were particularly interested in the working styles of students while they solved problems and looked for changes in these styles, as compared to traditional paper and pencil activities. While students worked on the computer, their activities (such as inputs from the keyboard, menu choices or mouse movements) were saved by a special program, which ran in the 'background'. We are interested in the possibilities of developing a research method based on these 'computer protocols'. The study should be seen as an exploratory study for developing hypotheses for further empirical investigations.
The interface between the host computer and an intelligent graphics terminal and the optimization of functional responsibilities of each become increasingly important in a time-sharing computer-aided design environmen...
详细信息
The interface between the host computer and an intelligent graphics terminal and the optimization of functional responsibilities of each become increasingly important in a time-sharing computer-aided design environment. This paper describes the implementation of the ACM/SIGGRAPA Core System on a DEC GT42 (W/PDP 11/10) and the CDC Cyber 74 as host computer.
It is shown how a system development team took formal methods beyond the farthest frontiers to achieve an unlikely project. This project showed that formal proofs do not have to be cumbersome and slow down the project...
详细信息
It is shown how a system development team took formal methods beyond the farthest frontiers to achieve an unlikely project. This project showed that formal proofs do not have to be cumbersome and slow down the project. In neither case were the formal methods tasks on the critical path. All the specification and proof work occurred in parallel with the rest of the project.
This paper deals with the statistics of estimating the software reliability of complex real-time systems where an electronic digital computer and associated computer programs are essential elements of system design an...
详细信息
This paper deals with the statistics of estimating the software reliability of complex real-time systems where an electronic digital computer and associated computer programs are essential elements of system design and function. Testing is conducted in the operating environment or a simulated environment related to the operating environment in some known way. The procedure is Bayesian so that improvement of reliability estimation is realized in a formal and convenient way as more and more test data are accumulated.
In order to take full advantage of the capabilities of very large computers, it is important that data structure and coding practices be carefully selected to efficiently use the special hardware features. The data st...
详细信息
In order to take full advantage of the capabilities of very large computers, it is important that data structure and coding practices be carefully selected to efficiently use the special hardware features. The data structure must be designed to stage information from the high speed, relatively small devices, to the lower speed, relatively large capacity devices. Coding practices must consider instruction stacks, cache memories, and main memory structure, in order to drive the arithmetic units at maximum speed. For virtual memory machines, the real memory must be used in such a manner as to prevent thrashing. Large machines may provide for scalar processing in parallel with vector processing, and the arithmetic units may utilize either parallel or pipeline processing.
The nature and value of investment in large Mathematical programmingsystems is assessed and an attempt is made to determine how it may be best used in the solution of current problems. Current MPS technology and deco...
详细信息
The nature and value of investment in large Mathematical programmingsystems is assessed and an attempt is made to determine how it may be best used in the solution of current problems. Current MPS technology and decomposition techniques are briefly surveyed and discussed. A detailed consideration is given to generalized upper bounding techniques and to mixed integer models. the DATAFORM data management system is explained. It is concluded that the really important technical areas to be improved now are data management and system control. It is suggested that a new type of organization be set up to continue the development of technology and provide uniform service to any legitimate client. The service organization should be nonprofit and not dependent on its direct revenues for funding.
To satisfy the requirements of real time applications, three techniques can be employed, involving either real time clock, programmable timers, or constrained programming. Designer of microcomputers will have the maxi...
详细信息
To satisfy the requirements of real time applications, three techniques can be employed, involving either real time clock, programmable timers, or constrained programming. Designer of microcomputers will have the maximum flexibility and power if a multitask executive system is available. In this paper, a nonpreemptive pseudo-asynchronous scheduler is adopted in a multitask system and implemented on a MCS6502 microcomputer. The programming example considered shows a number of superior characteristics absent in the constrained programming implementation. The storage overhead of the multitask approach can only be justified when the number of concurrent running processes is large.
This article presents a description and an evaluation of a time-sharing computer program written to implement a man-machine interactive algorithm for the solution of the multiple criteria problem. The evaluation is ba...
详细信息
This article presents a description and an evaluation of a time-sharing computer program written to implement a man-machine interactive algorithm for the solution of the multiple criteria problem. The evaluation is based on the experiences of two groups of subjects who were presented with a hypothetical problem asking them to select their preferred combination of cost, horsepower, and mileage for a new automobile.
暂无评论