The potential of the parasitoid Aphidius rhopalosiphi for controlling cereal aphids was tested in 16 m2 field cage experiments in 1998 and 1999. In the first year, aphids and parasitoids were released in cages containing naturally occurring populations of aphids and their natural enemies. In the second year, aphids and parasitoids were released in cages which had been cleared of insects by applying insecticide. The growths of the aphid populations in the different cages were analysed and compared. In 1998, the release of 50 pairs of parasitoids per cage had no significant effect on aphid population growth relative to that in the control cages. Even though the aphid population growth rates were less than 60% of that in the control cages, in the cages in which 100 pairs and 200 pairs of parasitoids were released, it was not possible to show they statistically differed. The aphid populations in these three cages were held below 10 aphids per tiller. In 1999, the aphid density was higher and the population grew faster than in 1998. The release of 100 and 200 parasitoids per cage significantly reduced aphid population growth. A. rhopalosiphi seemed to be a good control agent in field cages, provided they were released at the beginning of aphid population growth.
This paper deals with the reliability of composite measurement consisting of true-false items obeying the Rasch model. A definition of reliability in the Rasch model is proposed and the connection to the classical definition of reliability is shown. As a modification of the classical estimator \textit{Cronbach's alpha}, a new estimator \textit{logistic alpha} is proposed. Finally, the properties of the new estimator are studied via simulations in the Rasch model.
A reliability of site movement assessments determined from GPS data monitored during eight two-day epoch measurements on the regional geodynamic EAST SUDETEN network (the Bohemian Massif, Central Europe) is discussed in details. Statistical tests of site positions processed by the BERNESE GPS software, their linear approximations for site movement velocity assessments and an establishment of probabilistic thresholds for reliability of the GPS data for regional geodynamic studies are delivered. The thresholds define necessary observation periods for annual epoch measurements performed on the networks with aim to obtain reliable movement estimates for geodynamic studies., Vladimír Schenk, Zdeňka Schenková, Jaroslaw Bosy and Bernard Kontny., and Obsahuje bibliografii
There is common, rather empirically supported knowledge within the
body of the System Analysis that complex interfaces (for example “man - machirie” interface within the hybrid system, or synapse in the human brain) susceptibly react both on the dimension of the task (i.e.: the number / type / domain of interface parameters / markers), and the level of uncertainty. In order to quantitatively evaluate this effect, the overview of the different concepts of interface is done first. Then the problem is analyzed on the background of geometrical considerations.
The results of the study indicate that even a low degree of uncertainty has significantly adverse eífect on the interface regularity (consequently the reliability of systems processes, as well) if the dimension of the pertinent task is sufficiently high.
Practical implication of this result for systém analytics is straightforward - keeping the dimension of the task as low as possible. The interface dimension higher than 5 is in the majority of tasks with moderate uncertainty considerably unfavorable. This result imposes serious constrain to the systems identification.
A number of factories, warehouses, power plants and other industrial buildings have been recognized as industrial culture heritage. At present considerable effort of architects and civil engineers is aimed at re-use of these structures in order to preserve their cultural and heritage value and to avoid wasting energy. However, heritage structures usually do not fulfil requirements of present codes of practice. Simplified conservative procedures of design of new structures given in present codes may lead to expensive repairs and losses of the cultural and heritage value when applied to existing structures. In accordance with EN 1990 and ISO 13822 a probabilistic procedure is proposed to improve the reliability assessment of industrial heritage buildings. The procedure is applied in the reliability assessment of a steel member. and Obsahuje seznam literatury
A robust prediction model is developed for reliably estimating vehicular consumption. This model is distinguished from other models proposed so far for the following reasons: it detects the factors contributing into vehicular consumption, it applies machine learning functionality for approximating the nonlinearities and the specificities between the contributing factors, and it is capable of implicitly adapting to the characteristics of the vehicle, the road network and the contextual conditions through its learning process. The authors validated its efficiency by applying it on measurements collected during a data acquisition campaign, which was performed by a fully electric vehicle (FEV) in an urban road network.