Replication of the first controlled experiment on the usefulness of design patterns: Detailed description and evaluation

Advocates of software design patterns claim that using design patterns improves communication between software developers. The controled experiment that we describe in this report tests the hypothesis that software maintainers of well-structured, well-documented software containing design patterns can make changes (1) faster and (2) with less errors if the use of patterns is explicitly documented in the software. The experiment was performed with 22 participants of a university course on C++ and design patterns; it is similar to a previous experiment performed in Karlsruhe. For one of the two experiment tasks the experiment finds that both hypotheses appear to be true. For the other task the results are inconclusive, presumably because the task was too difficult for the given experience level of the subjects

Prevalence of major pig production diseases in 2 provinces of Northern Vietnam (Hoa Binh and Vinh Phuc)

Over the recent years ILRI has been working in the pig value chain in selected regions of Vietnam with focus on pig productivity and doing assessments of animal health and food safety constraints using various tolls such as PRA, questionnaires and participatory methods. Diseases in pigs have been identified as a key constraint by farmers and other VC actors. In order to prioritize interventions to improve productivity in pigs in Vietnam, there is a need to better understand the prevalence of various potentially important production diseases and underlying pathogens. Available information is scarce or not updated. Therefore the aim of this project is to test samples collected in a cross-sectional on-farm screening for various diseases of relevance for pig productivity

The impact of inheritance depth on maintenance tasks: detailed description and evaluation of two experiment replications

Inheritance is one of the main concepts of object-oriented technology. It is claimed that the use of inheritance improves productivity and decreases development time. John Daly et al. reported on two experiments evaluating the effects of inheritance depth on program maintenance. They found that maintenance was performed significantly quicker for software using three levels of inheritance, compared to equivalent `flattened\u27 software without inheritance. A second experiment found that maintenance for software using five levels of inheritance tended to be slightly slower than for equivalent software without inheritance. We report on similar experiments on the same question. Our results contradict those mentioned above. Several crucial changes were made to the setup. In particular longer and more complex programs were used, an inheritance diagram was available to the subjects, and we used more and different kinds of maintenance tasks. Furthermore, our experiment design compares zero level, three level and five level inheritance directly in one experiment. The results suggest that there is a tendency that deeper inheritance may complicate program understanding. But the effect depends rather on other factors such as complexity of the program and type of maintenance task than on inheritance depth. We found a high correlation between maintenance time and the number of methods to trace to gain program understanding. Further work should be done to identify other influence factors

Gesture categorisation and understanding speaker attention to gesture

The field of gesture classification has b Abstract een an area of intense scholarship in recent decades. This article provides a brief overview of the area in seeking to understand how this theoretical framework relates to the way speakers attend to gestural information. 48 native English speakers participated in a web-based survey centred on a short narrative. The gestures focused on in the film narrative were based around McNeill’s common gesture typology. Half of the participants watched the video with sound and the other half without to help ascertain whether the presence of speech affects how people attend to gestural information. Participants were asked to count the total number of gestures and list what they thought the five “best” examples of a gesture were. While there was no significant difference between the number of gestures counted by each group, the categories of gesture which were attended to varied between the two groups. Those with sound were more likely to include iconic gestures while those without were more likely to attend to beat gestures. This indicates that the presence or absence of sound has no affect on how many gestures participants observe, but it does affect what gestural information they pay more attention to