Comprehensibility of UML-based Formal Model – A Series of Controlled Experiments

This paper summarises two controlled experiments conducted on a model that integrates the use of semi-formal notation, the Unified Modelling Language (UML) and a formal notation, B. The experiments assessed the comprehensibility of the model, namely UML-B. The first experiment compared the comprehensibility of a UML-B model and a B model. In the second experiment, the model was compared with an Event-B model, a new generation of B. The experiments assessed the ability of the model to present information and to promote problem domain understanding. The measurement focused on the efficiency in performing the comprehension tasks. The experiments employed a cross-over design and were conducted on third-year and masters students. The results suggest that the integration of semi-formal and formal notations expedites the subjects’ comprehension tasks with accuracy even with limited hours of training

Can worms be controlled by correct feeding?

THE extensive losses which result from the ravages of internal parasites are a matter of serious concern. Livestock owners realise this all too well and welcome advice concerning control measures which can be adopted. Unfortunately, it is not possible to give clear cut advice on the subject. Much publicity is given to the use of drugs which will expel the worms. Various systems of strategic drenching have been developed. It is well to remember, however, that drenching is only one of many methods which can be used to control worm infestation. In this talk attention will be concentrated on experimental evidence which shows that good husbandry in general, and good feeding in particular, may greatly reduce the worm burden carried by livestock

Tree lucerne : a fodder crop with a future

IN December, 1952, an article was published in this Journal drawing attention to the potential value of white flowered tree lucerne (Cytisus prolifer) as a source of nutritious green fodder during the dry summer months. Figures were quoted to show that heavy yields could be obtained year after year with very little effort, and no outlay other than for fertiliser. The advantages to be gained from the cultivation of this tree were made very apparent and many farmers set out to grow the shrub

The use of dried buttermilk to rear calves.

Only a limited number of calves are reared on dairy farms which sell whole milk. At current prices, it is only a very good calf which is worth more than the milk it would consume, and as a result, the heifer calves from thousands of productive cows are each year slaughtered at birth. In the past the whole milk supplier was able to obtain his herd replacements from farmers in the more distant dairying districts who of necessity sold butterfat and could rear calves on separated milk

Cobalt

Cobalt is one of the most interesting of the so-called trace elements. Particularly is this so to West Australians as the use of cobalt has permitted farmers to rear healthy sheep and cattle where previously this was impossible. Also, it was in this State that Filmer and Underwood carried out much of the fundamental work which led to the discovery of the vital importance of cobalt

A simple and effective cow bail

While visiting the property of Mr. R. Burke, Cowaramup, I saw in use a type of cow-bail which made an immediate appeal because of its simplicity, effectiveness and ease of working. Mr. Burke is obviously skilled at setting up practical time-saving devices but there seems to be no reason why other dairy farmers should not make use of the principle he employed