Experiments on the programming process and on software science are undertaken to help scientists better understand and so improve the development, testing, and maintenance of programs. Here examined are several gener...
Experiments on the programming process and on software science are undertaken to help scientists better understand and so improve the development, testing, and maintenance of programs. Here examined are several general issues of experiment design and how they apply to the design of programming experiments. Some pitfalls to avoid in the design of valid experiments are discussed, including some methods of avoiding them, illustrated by reviewing how they were dealt with in an experiment taken from the literature. Issues covered include: 1. subject selection, 2. material selection, 3. subject assignment, 4. data collection, and 5. statistical techniques. Design issues are divided into internal validity and external validity problems.
This paper describes the principles underlying an efficient implementation of a lazy functional language, compiling to code for ordinary computers. It is baaed on combinator-like graph reduction: the user defined func...
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作者：
Jones, T.CapersITT
Programming Technology Cent Stratford CT USA ITT Programming Technology Cent Stratford CT USA
The term quality is used here to mean an absence of defects that would cause a program to behave unpredictably or stop successful execution. There are two fundamental ways of minimizing programming defects that signif...
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The term quality is used here to mean an absence of defects that would cause a program to behave unpredictably or stop successful execution. There are two fundamental ways of minimizing programming defects that significantly determine quality measurements. One is to prevent defects from occurring. The other is to remove defects that have occurred. Therefore, quality measurements are related to restricting the quantity of defects that come into existence, and their efficient removal by various kinds of reviews and tests used in programming.
Flicker was studied as perceived on a raster-scan CRT-based computer terminal in a typical use environment. The subject of the research was the relationship between the perception of flicker and the kind of spatial im...
Flicker was studied as perceived on a raster-scan CRT-based computer terminal in a typical use environment. The subject of the research was the relationship between the perception of flicker and the kind of spatial image presented. Both traditional images (filled white disks or squares) and images consisting of text and line drawings, similar in content to typical graphic computer terminal displays, were used in the study. This study measured the flicker perception of eight *** most significant finding from this study was that CFF thresholds for some images presented on CRT displays in a typical use setting, differed significantly from more traditional images used in most CFF studies reported in the literature. For the eight images tested, the two which exhibited significantly higher CFF thresholds were lines or text on a black background (patterns 3 and 4). Therefore, an important factor to be considered in the prediction of the flicker characteristics of a 60 Hertz, noninterlaced CRT display in conditions similar to those of this study is the choice of normal video (black background) or reverse video format. The white background video format is likely to flicker when the display luminance is above 20 ft-L while the black background video format threshold was about 80 ft-L for both patterns 3 and 4. Alternatively, this luminance difference corresponds to about a 10 Hertz shift in *** this study, the choice of video format alone, resulted in a luminance difference of 60 ft-L at CFF, or alternatively, resulted in a 10 Hertz shift in CFF at a particular luminance, for images normally found on actual CRT displays.
This paper presents a partial review of the human factors work on computer programming. It begins by giving an overview of the behavioral science approach to studying programming. Because of space limitations this rev...
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The concept of prime program is applied as a decomposition technique to the global data flow analysis problem. This is done both in the abstract and through the use of the live variables problem as an example, it is a...
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The NBS Data Encryption Standard may be integrated into computer networks to protect personal (nonshared) files, to communicate securely both on- and off-line with local and remote users, to protect against key substi...
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The NBS Data Encryption Standard may be integrated into computer networks to protect personal (nonshared) files, to communicate securely both on- and off-line with local and remote users, to protect against key substitution, to authenticate system users, to authenticate data, and to provide digital signatures using a nonpublic key encryption algorithm. Key notarization facilities give users the capability of exercising a set of commands for key management as well as for data encryption functions. The facilities perform notarization which, upon encryption, seals a key or password with the identities of the transmitter and intended receiver. Thus, in order to decrypt a message, the receiver must authenticate himself and supply the correct identity of the transmitter. This feature eliminates the threat of key substitution which must be protected against to attain a high level of security.
Per Martin-Löfs Constructive Set Theory is a mathematical language with computation rules. It is primarily designed to be a language for mathematical reasoning. The language has a very simple semantics and its ru...
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ISBN:
(纸本)0897910605
Per Martin-Löfs Constructive Set Theory is a mathematical language with computation rules. It is primarily designed to be a language for mathematical reasoning. The language has a very simple semantics and its rules have a simple structure. Since it is a language for constructive mathematics, it is possible to execute the proof (the construction of a proposition) as a program. The language can be seen as a programming language without assignments and other side effects. Compared to traditional functional languages it has a very rich type structure in that the type of an expression can completely specify the task of the expres-tion. A sorting algorithm, for instance, can be conventionally specified to have a type sort: List(A) List(A) which is type-correct if sort is any function taking a list as argument and producing a list as result. It is, however, also possible to specify that sort is a function taking a list as argument and producing a sorted permutation of its input as result, i.e. sort:(l/x £ List(A)) (vy tList(A)) (Perm(x,y) x Sorted(y)) The type (or the task) of the program can be read as the proposition (Vx 6 List(A)) (3y e List(A) (Perm(x,y) & Sorted(y)) which is read "for all lists x, there is a sorted permutation y of x". We can prove that this proposition is true, using the rules of the language to construct a program for the task. If the proposition were not true, it would be impossible to find a a program for it and we would have had an impossible task. The types of Constructive Set Theory can be seen as a specification language for the programs, but of course there is only one language, avoiding the complexity of mixing a programming language with a logical language. The similarity (or rather: identity) between a mathematical proof of a given proposition and a program for a given task suggests that programming should be similar to the mathematicians activity of finding proofs. We have illustrated this with an example of how a proof of the Euclidean
Dickey's critique of the Sackman et al. data is well taken. An alternate data set is presented which substantiates the enormous variability in programmer performance. The opportunity for productivity gains and imp...
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Dickey's critique of the Sackman et al. data is well taken. An alternate data set is presented which substantiates the enormous variability in programmer performance. The opportunity for productivity gains and improved experimental methods in research through reducing the range of this variability remains fertile.
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