Automating requirements analysis and test case generation

Requirements Engineering - Writing clear and unambiguous requirements that are conflict-free and complete is no easy task. Incorrect requirements lead to errors being introduced early in the design...     

A mutual assessment of the uncertainties of digital elevation models using the triple collocation technique

This study investigates the uncertainties of digital elevation models (DEMs) using the triple collocation (TC) method. DEMs from satellite missions are important for many geoscience disciplines and for economic benefits and are freely available. Validating DEMs is necessary to select an appropriate model for a given region and application. Provided certain assumptions about the error structure of any three data sets – measuring the same phenomenon – can be made, the TC approach can be used to provide an unbiased and scaled estimate of the error variances of the data sets, without requiring a reference data. We compared the TC approach to the traditional approach of using a reference data set using the Shuttle Radar Topography Mission version 4.1 (SRTM v4.1) DEM, ASTER (the Advanced Spaceborne Thermal Emission and Reflection Radiometer) GDEM (Global DEM) version 2, the 1 arc-minute global relief model (ETOPO1), a DEM compiled by the Survey and Mapping Division of Ghana (SMD DEM), and 545 ground control stations (GCSs). The error estimates for the DEMs via TC were considerably smaller than those obtained from the reference-based approach. As an example, the best performing DEM (SRTM v4.1) recorded a root-mean-square error (RMSE) of 15.601 m using the GCSs as reference, while its TC-derived accuracy was 6.517 m. We note that based on the results of the TC, the estimated error of the GCSs is approximately 14 m. Using a data set with an error of 14 m to validate other data sets is certainly bound to result in unfavorable results. Thus, we have demonstrated in this work that the TC approach is able to provide an unbiased error of DEMs. The approach is important even for regions where GCSs are highly accurate, but more so for regions with low-quality GCSs.     

Sharing Political Content in Online Social Media: A Planned and Unplanned Behaviour Approach

Human’s decision making is not necessarily always planned; their unplanned behaviour—determined by natural personality traits—also contributes to the decision making process. In this study, we investigate factors related to planned and unplanned behaviour to understand why people share political content in online social media. Based on an online survey of 257 social media users, our results demonstrate that the factors representing both planned (i.e., perceived social recognition and altruistic motivation) and unplanned behaviour (i.e., extroversion and impulsiveness) affect people’s political content sharing behaviour. Our study understands that sharing political content is not like sharing other forms of content such as tourist attractions—the former can provoke serious punishment in some countries. Accordingly, trait impulsiveness is negatively associated with political content sharing behaviour. We also found that collective opinion moderates people’s planned behaviour, but not their unplanned behaviour. In other words, personality traits are unaffected by others’ opinions, but traits that humans can control can be shaped by others’.     

Complex Transfinite Barycentric Mappings with Similarity Kernels

Transfinite barycentric kernels are the continuous version of traditional barycentric coordinates and are used to define interpolants of values given on a smooth planar contour. When the data is two‐dimensional, i.e. the boundary of a planar map, these kernels may be conveniently expressed using complex number algebra, simplifying much of the notation and results. In this paper we develop some of the basic complex‐valued algebra needed to describe these planar maps, and use it to define similarity kernels, a natural alternative to the usual barycentric kernels. We develop the theory behind similarity kernels, explore their properties, and show that the transfinite versions of the popular three‐point barycentric coordinates (Laplace, mean value and Wachspress) have surprisingly simple similarity kernels. We furthermore show how similarity kernels may be used to invert injective transfinite barycentric mappings using an iterative algorithm which converges quite rapidly. This is useful for rendering images deformed by planar barycentric mappings.     

Meta-analysis of indoor temperatures in new-build housing

ABSTRACT

Despite growing concerns about overheating, a lack of evidence exists on the scale of the problem, particularly in contemporary UK housing. This paper presents the results of a meta-analysis of indoor temperatures in selected low-energy housing. Temperature data recorded at five-minute intervals in 60 dwellings across 19 demonstration projects (2012–14) were collated and analysed to investigate the prevalence of overheating. Findings evidence high summertime temperatures, with 27% of living rooms exceeding 28°C during August. Based on the Chartered Institution of Building Services Engineers (CIBSE) threshold of 5% annual occupied hours > 25°C, 57% of bedrooms and 75% of living rooms were classified as having overheated. Overall, 30% of living rooms exceeded the adaptive comfort threshold of > 3% occupied hours ΔT?≥?1?K. The results suggest a fundamental relationship between ventilation and indoor temperatures. The higher minimum and average summertime temperatures observed in mechanical ventilation with heat recovery (MVHR) homes (p?<?0.05) and lower temperature range (p?<?0.001) suggest the need for greater attention to adequate summertime ventilation provision in airtight homes. The results demonstrate a high prevalence of overheating in exemplary housing, indicating the need for greater efforts to ensure the effective implementation of strategies to minimize overheating and improve ventilation in low-energy homes.     

Densitometric evaluation of lung aeration in chest films

Lung aeration can be evaluated densitometrically from chest films, using a microscope with one eyepiece replaced by a photocell, and the attenuation of the pulmonary parenchyma can be assessed numberically, as a "radiologic expansion index". In premature rabbit neonates, this index was significantly increased among animals receiving a pharyngeal deposit of homologous lung surfactant before the first breath, as compared with untreated controls. This technique could in modified form be used for clinical purposes, such as the evaluation of lung aeration in newborn infants with respiratory distress.     

Dilatometric errors and an application to volume changes for the solid state of methyl stearate

Summary The dilatometric curves representing heating and cooling cycles for methyl stearate between-38°C. and +35°C. are the same shape as found in the previous study. Cooling cycles which are started from points on the heating curve yield curves which are different from each other and from curves representing the complete heating and cooling cycles. Curves for heating cycles which are started from points on the curve representing the complete cooling cycle will also be different from the curves representing either the heating or cooling cycles in the same temperature region. The specific volumes at any temperature in the solid region depend on the previous history of the sample even though the sample is not melted between determinations. A continual reduction in specific volume was found for successive runs after equilibration at+35°C. This reduction had no apparent effect on the coefficient of expansion of the solid state but did increase the melting dilation. Using the present Vycor dilatometers, the standard error of measurements in the solid state are around ±0.00005 ml. per gram in terms of specific volume. The use of a platinum resistance thermometer and Mueller bridge did not significantly improve the precision of the measurements. Presented at the fall meeting, American Oil Chemists' Society, Philadelphia, Pa., Oct. 10–12, 1955. Issued as N.R.C. No. 4178.     

Production and utilization of rapeseed in Canada

Production of rapeseed began in Canada in 1942 mainly in response to a demand for an industrial lubricating oil. Favorable response in agricultural production stimulated interest in developing a rapeseed industry to supply a domestic requirement for vegetable oils, an alternate crop for agriculture and an export commodity. Seeded acreages recently increased rapidly to around four million acres and Canada has become a major exporter of rapeseed. One of 9 papers presented at the Symposium, “Cruciferous Oilseeds”, ISF-AOCS World Congress, Chicago, September 1970. NRCC No. 12250.     

Silicic acid-silver nitrate chromatography as an enrichment technique in fatty acid analysis

Silicic acid-silver nitrate chromatography as developed by De Vries (8,9) is a valuable tech-nique for the quantitative determination of satu-rated fatty acids, and enrichment of fractions which permit the analysis of trace quantities of unusual fatty acids. Odd numbered fatty acids have been found in both saturated and monoene fractions of vegetable oils, such as olive, rapeseed and sunflowerseed. This technique coupled to oxi-dative degradation is useful for establishing the presence of minor quantities of positional isomers. Samples of purified polyunsaturated fatty acid esters are readily prepared using the technique as displacement chromatography. Presented in part at the AOCS Meeting in Minneapolis, 1963. Issued as NBC No. 7983. National Research Council of Canada Postdoctorate Fellow 1962-.