The increasing complexity of computer and communication systems in use today has raised the levels of risks of exposure to failure and accidents. One approach to address this problem is by reducing the incidence of un...
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The increasing complexity of computer and communication systems in use today has raised the levels of risks of exposure to failure and accidents. One approach to address this problem is by reducing the incidence of unnecessary complexities which stem from the mapping of application functions onto poor or inappropriate execution platforms. The unnecessary complexities may be addressed by restructuring the hardware and software architecture complex. In addition to this, disciplined structuring and execution of life cycle processes with the support of appropriate methods and tools are needed.
Exploratory programmingsystems, previously confined to the artificial intelligence field, are becoming attractive for many commercial applications. Since they allow designers to defer programming decisions or to avoi...
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Exploratory programmingsystems, previously confined to the artificial intelligence field, are becoming attractive for many commercial applications. Since they allow designers to defer programming decisions or to avoid them entirely, these systems can cope with rapidly changing, very large application programs. The need for this kind of programming system has come about because some projects are simply not solvable with more conventional programming methods.
An in-place reversible sorting algorithm is used following a fast Walsh transform to sort coefficients into increasing sals followed by decreasing cals. This separation of the coefficients into those arising from odd ...
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An in-place reversible sorting algorithm is used following a fast Walsh transform to sort coefficients into increasing sals followed by decreasing cals. This separation of the coefficients into those arising from odd sinelike time functions and those from even cosinelike functions is useful in signal processing applications. A second sort routine generates a relocating set for a remap sequency sorting. To be valid for all N this sort routine is done out-of-place. The separation of the transform and sort functions has resulted in simple implementations for each. To demonstrate the differences in the sort routines, transform results and their inverses are made on a linear ramp. For this application the transform results with sal-cal sorting has all zeros beyond the mid-point showing that, with the exception of the large d. c. term, the linear ramp is composed entirely of Walsh odd time functions.
In today's multifaceted engineering environment, documentation must be viewed as a design effort similar in concept to hardware/software design. The phases common to hardware/software design find counterparts in d...
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In today's multifaceted engineering environment, documentation must be viewed as a design effort similar in concept to hardware/software design. The phases common to hardware/software design find counterparts in documentation design as well. The predominant design phases include architecture, design, implementation, integration, test, and manufacture. Individual documentation requirements form a hierarchy of documentation types with each document fulfilling a specific purpose. Developing the documentation structure using structural technique is described.
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...
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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...
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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 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 ...
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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&...
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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.
After analyzing the steps leading to the development of a program for a microprocessor based control system it is found that the programming language to be used should not obscure to the designer the precise operation...
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After analyzing the steps leading to the development of a program for a microprocessor based control system it is found that the programming language to be used should not obscure to the designer the precise operation of the system. It also should reflect the symbolism of the system analyst. programming in an assembly-like language with the aided potential for calling bit-oriented data structures by name, is found to be adequate and can be achieved by using a preprocessing pass. The source text is translated into regular assembler text. This idea is applied to programming INTEL's 8080.
The ISI Delta Experiment is an effort to specify and verify a piece of real software of moderate complexity and size (roughly 1000 lines). This preliminary report describes (1) the Delta function, managing the editing...
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The ISI Delta Experiment is an effort to specify and verify a piece of real software of moderate complexity and size (roughly 1000 lines). This preliminary report describes (1) the Delta function, managing the editing of a single file by several users within an operational message processing system; (2) the formal specification of the Delta function in prose and in algebraic axioms; (3) the verification methodology in levels of (a) prose for the system interface level, (b) algebraic axioms for abstract data types, (c) recursive functions for major operations, (d) implementation of the recursive functions in PASCAL with the abstract data types, and (e) implementation of the PASCAL programs in BLISS; and (4) the experience gained in this experiment, both in specification and verification.
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