Implementation of Ada protocols on Mil-STD-1553 B data bus

Standardization activity of data communication in avionic systems started in 1968 for the purpose of total system integration and the elimination of heavy wire bundles carrying signals between various subassemblies. The growing complexity of avionic systems is straining the capabilities of MIL-STD-1553 B (first issued in 1973), but a much greater challenge to it is posed by Ada, the standard language adopted for real-time, computer embedded-systems. Hardware implementation of Ada communication protocols in a contention/token bus or token ring network is proposed. However, during the transition period when the current command/response multiplex data bus is still flourishing and the development environment for distributed multi-computer Ada systems is as yet lacking, a temporary accomodation of the standard language with the standard bus could be very useful and even highly desirable. By concentrating all status informtion and decisions at the bus controller, it was found to be possible to construct an elegant and efficient harware impelementation of the Ada protocols at the bus interface. This solution is discussed

Energia-válaszút előtt

Bernard Frois arra kért, hogy néhány rendhagyó, sőt vitatható megjegyzést tegyek. Kérésének nagyon szívesen teszek eleget, mivel az intellektuális provokatőr szerepe mindig is a kedvencem volt. Néhány következtetésem, így meggyőződésem is ellenkezik számos elvárással, ígérettel és előrejelzéssel, melyeket a következő két napban hallanak majd: megrögzött szkeptikusként egyelőre nem vagyok meggyőződve a fényes kilátásokról, azoknak az eljárásoknak és újításoknak a lehetséges léptékéről és üteméről, amelyeket a következő előadások majd fölmagasztalnak. Szeretnék megértetni Önökkel fél tucat alapvető tényt, amelyek egytől-egyig axiómákon, nem pedig hiú ábrándokon alapulnak, és amelyek nem egy-egy előnyben részesített megoldás pártolásáról szólnak. Minden esetben szolgálok legalább egy vagy két egyszerű, és reményeim szerint megjegyezhető számszerű adattal annak érdekében, hogy a legfontosabb pontokat kiemeljem

Intermediate Agricultural Machines Energy Efficiency: The Example of Harvesting and Threshing

The article compares fifteen different methods used to harvest and thresh wheat, from traditional manual solutions, to animal traction machines to modern combine harvesters. For each methodology, individual productivity in terms of field area worked in a unit of time by each individual operator, and specific productivity, in terms of field area worked per unit of energy are calculated. These parameters are related to the power available for each operator involved in the process, whether deriving from their muscles, animal prime mover or heat engine. The analysis shows that increasing individual power increases productivity, although with a reduced gradient at high powers. On the other hand, low power solutions are up to ten times more energy efficient, confirming that intermediate technologies can be an appropriate solution with a view to sustainability

Assessing the energy implications of replacing car trips with bicycle trips in Sheffield, UK

A wide range of evidence supports policies which encourage people to cycle more and drive less, for health and environmental reasons. However, the likely energy implications of such a modal shift have remained relatively unexplored. In this paper we generate scenarios for increasing the cycling rate in Sheffield between 2010 and 2020. This is done through the novel application of a simple model, borrowed from population ecology. The analysis suggests that pro-cycling interventions result in energy savings through reduced consumption of fuel and cars, and energy costs through increased demand for food. The cumulative impact is a net reduction in primary energy consumption, the magnitude of which depends on a number of variables which are subject to uncertainty. Based on the evidence presented and analysed in this paper, we conclude that transport policy has a number of important energy implications, some of which remain unexplored. We therefore advocate the formation of closer links between energy policy and transport policy in academia and in practice; our approach provides a simple yet flexible framework for pursuing this aim in the context of modal shift

Linking remote-sensing estimates of land cover and census statistics on land use to produce maps of land use of the conterminous United States

Human use of the land has a large effect on the structure of terrestrial ecosystems and the dynamics of biogeochemical cycles. For this reason, terrestrial ecosystem and biogeochemistry models require moderate resolution (e.g., ≤0.5°) information on land use in order to make realistic predictions. Few such data sets currently exist. To create a land use data set of sufficient resolution, we developed models relating land cover data derived from optical remote sensing and a census database on land use for the conterminous United States. The land cover product used was from the International Geosphere-Biosphere Programme DISCover global product, derived from 1 km advanced very high resolution radiometer imagery, with 16 land cover classes. Land use data at state-level resolution came from the U.S. Department of Agriculture\u27s Major Land Uses database, aggregated into four general land use categories: Cropland, Pasture/Range, Forest, and Other. We developed and applied models relating these data sets to generate maps of land use in 1992 for the conterminous United States at 0.5° spatial resolution

Evolution not revolution of farming systemswill best feed and green the world

The challenge to properly feed a world population of 9.2 billion by 2050, that must be achieved on essentially currently cropped area, requires that food production be increased by 70%. This large increase can only be achieved by combinations of greater crop yields and more intensive cropping adapted to local conditions and availability of inputs. Farming systems are dynamic and continuously adapt to changing ecological, environmental and social conditions, while achieving greater production and resource-use efficiency by application of science and technology. This article argues that the solution to feed and green the world in 2050 is to support this evolution more strongly by providing farmers with necessary information, inputs, and recognition. There is no revolutionary alternative. Proposals to transform agriculture to low-input and organic systems would, because of low productiv- ity, exacerbate the challenge if applied in small part, and ensure failure if applied more widely. The challenge is, however, great. Irrigation, necessary to increase cropping intensity in many areas cannot be extended much more widely than at present, and it is uncertain if the current rate of crop yield increase can be maintained. Society needs greater recognition of the food-supply problem and must increase funding and support for agricultural research while it attends to issues of food waste and over consumption that can make valuable reductions to food demand from agricultur