Publications by authors named "David Flater"

The SI brochure's treatment of quantities that it regards as dimensionless, with the associated unit one, requires certain physical quantities to be regarded as simply numbers. The resulting formal system erases the nature of these quantities and excludes them from important benefits that quantity calculus provides over numerical value calculations, namely, that accidental confusion of different units and different kinds of quantities is sometimes prevented. I propose a better treatment that entails removing from the SI brochure those prescriptions that conflict with common practices in the treatment of dimensionless quantities, especially the definition and use of non-SI dimensionless units that are distinguished by kind.

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International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) 80000, the International System of Quantities, collects and organizes the most important physical quantities into a coherent system of quantities whose foundation for measurements is the International System of Units (SI). This short communication outlines a report that, in a similar fashion, collects and organizes the most important quantities used in measurements performed on software artifacts, focusing on software as a product rather than its development process.

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A quantity value, such as 5 kg, consists of a number and a reference (often an International System of Units (SI) unit) that together express the magnitude of a quantity. Many software libraries, packages, and ontologies that implement "quantities and units " functions are available. Although all of them begin with SI and associated practices, they differ in how they address issues such as counting units, ratios of two quantities of the same kind, and uncertainty.

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The International System of Units (SI) and its associated methods adhere to a design principle in which all kinds of quantities are described in terms of a standard set of dimensions. It is a corollary of that principle that quantities having no extent in any of those dimensions ("dimensionless quantities") will not be distinguishable as different kinds through dimensional analysis alone, and the formality of quantity calculus will be of no help in preventing mistakes where different kinds of dimensionless quantities are confused. This corollary has led to controversies involving abuse of the unit hertz and elimination of radians and steradians as being equivalent to the number 1.

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Programmers routinely omit run-time safety checks from applications because they assume that these safety checks would degrade performance. The simplest example is the use of arrays or array-like data structures that do not enforce the constraint that indices must be within bounds. This report documents an attempt to measure the performance penalty incurred by two different implementations of bounds-checking in C and C++ using a simple benchmark and a desktop PC with a modern superscalar CPU.

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Conceptual integrity is required for the result of data integration to be cohesive and sensible. Compromised conceptual integrity results in "semantic faults," which are commonly blamed for latent integration bugs. A logical model of conceptual integrity in data integration and a simple example application are presented.

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