258 research outputs found
Curvature-direction measures of self-similar sets
We obtain fractal Lipschitz-Killing curvature-direction measures for a large
class of self-similar sets F in R^d. Such measures jointly describe the
distribution of normal vectors and localize curvature by analogues of the
higher order mean curvatures of differentiable submanifolds. They decouple as
independent products of the unit Hausdorff measure on F and a self-similar
fibre measure on the sphere, which can be computed by an integral formula. The
corresponding local density approach uses an ergodic dynamical system formed by
extending the code space shift by a subgroup of the orthogonal group. We then
give a remarkably simple proof for the resulting measure version under minimal
assumptions.Comment: 17 pages, 2 figures. Update for author's name chang
Comparison of two sowing systems for CTF using commercially available machinery
ArticleThe crop establishment belongs to crucial
technology operations. The quality of
sowing is the basis for obtaining efficiency of production. Controlled Traffic Farming (CTF) is a
technology which prevents excessive soil compaction and minimizes compacted area to the
smallest possible area of perman
ent traffic lanes (PTL). There were two sowing systems
compared, namely row and band sowing when growing winter barley. Sowing parameters as well
as all other field operations were identical for both compared systems. Measurements were
conducted at an expe
rimental field on non
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compacted and traffic lane areas where CTF system
was introduced in 2009, with 64% of compacted and 36% of non
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compacted soil. Six crop
parameters were analysed. Generally, it can be concluded that the band sowing performed better
in
yield (by 9.3% in non
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compacted area; by 3.8
%
in traffic lane), ear number (by 5.2% in non
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compacted area; by 10.1% in traffic lane) and grain number (by 6.3% in non
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compacted area; by
8.1% in traffic lane) as well as crop height (by 6.6% in non
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compacted
area; and by 2.4% in
traffic lane). The only parameter performing worse was TGW with decrease of 6.6% in non
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compacted area and decrease 2.8% in traffic lane for band system. Differences in number of grain
per ear were negligible
Effect of controlled traffic farming on weed occurrence
ArticleSoil compaction caused by field traffic is one of the most important yield limiting
factors. Moreover, published results report that soil over-compaction inhibits the uptake of plant
nutrients and decreases their ability to compete with weeds. Controlled Traffic Farming (CTF) is
technology which prevents excessive soil compaction and minimizes compacted area to the least
possible area of permanent traffic lines. A long-term experiment was established at University
farm in Kolinany (Slovakia) in 2010 with 6 m OutTrack CTF system. Random Traffic Farming
(RTF) is simulated by 1 annual machinery pass crossing the permanent traffic lines. Aim of
presented study was to assess the effect of CTF on weed infection pressure. To achieve this, weed
occurrence at different traffic treatments was determined. Emerged weeds per square meter were
counted, identified and recorded at 14 monitoring points. Results showed that higher weed
infection was found at the area with one machinery pass compared to the non-compacted area.
Following weeds were identified: Bromus secalinus L., Stellaria media (L.) VILL., Veronica
persica POIR. in LAMK., Poa annua L., Polygonum aviculare L., Convolvulus arvensis L.
Occurrence of these weeds could be used as soil compaction indicator. Based on these results it
can be concluded, that CTF technology has potential to decrease weed infestation in comparison
to RTF system due to ration of non-compacted to compacted area. Moreover, with exact
localization of weeds in traffic lines together with exact identification of weed species, it is
possible to target the application of herbicides
Paving the pathways towards sustainable future? A critical review of STI policy roadmaps as policy instruments enabling sustainability transitions
Roadmaps and roadmapping techniques receive increasing attention in the Science, Technology and Innovation policy community, notably for the development of strategies and policies to address societal challenges and ambitious goals such as the SDGs. STI policy roadmaps are used to evoke future visions, align actor expectations and formulate, document, plan and implement public policies for long-term, ambitious sustainability goals. As a sophisticated strategic planning process, roadmapping seems appropriate for policy support aiming to foster sustainability transitions. Nevertheless, there is little research on the role and limitations of roadmaps as a policy instrument to support innovation for sustainability transitions. This paper critically assesses selected national and international policy and sectoral roadmaps that focus on technology areas and societal challenges relevant to sustainability and energy transitions. The assessment of the objectives, design features and embeddedness of roadmaps in policy processes shows that current policy roadmaps have several shortfalls. The paper outlines knowledge gaps and research priorities to understand how such limitations might be overcome and draws tentative lessons for future applications of roadmaps as policy instruments for sustainability transitions
Delays in IP routers, a Markov model
Delays in routers are an important component of end-to-end delay and therefore have a significant impact on quality of service. While the other component, the propagation time, is easy to predict as the distance divided by the speed of light inside the link, the queueing delays of packets inside routers depend on the current, usually dynamically changing congestion and on the stochastic features of the flows. We use a Markov model taking into account the distribution of the size of packets and self-similarity of incoming flows to investigate their impact on the queueing delays and their dynamics
Modelling and Analysing Mixed Reality Applications
International audienceMixed reality systems overlay real data with virtual information in order to assist users in their current task. They generally combine several hardware components operating at different time scales, and software that has to cope with these timing constraints. MIRELA, for MIxed REality LAnguage, is a framework aimed at modelling, analysing and implementing systems composed of sensors, processing units, shared memories and rendering loops, communicating in a well-defined manner and submitted to timing constraints. The framework is composed of (i) a language allowing a high level, and partially abstract, specification of a concurrent real–time system, (ii) the corresponding semantics, which defines the translation of the system to concrete networks of timed automata, (iii) a methodology for analysing various real-time properties, and (iv) an implementation strategy. We present here a summary of several of our papers about this framework, as well as some recent extensions concerning probability and non–deterministic choices
Comparison of simulation and analytical models for the distribution of a group of agents moving in random directions
This study focused on simulation and analytical models of a multidimensional random walk of many agent
Determining trafficked areas using soil electrical conductivity – a pilot study
ncrease in machinery size and its random traffic at fields cause soil compaction resulting in damage of soil structure and degradation of soil functions. Nowadays, rapid methods to detect soil compaction at fields are of high interest, especially proximal sensing methods such as electrical conductivity measurements. The aim of this work was to investigate whether electromagnetic induction (EMI) could be used to determine trafficked areas in silty clay soil. Results of randomized block experiment showed a high significant difference (p <0.01) in EMI data measured between compacted and non-compacted areas. EMI readings from compacted areas were, on average, 11% (shallow range) and 9% (deep range) higher than non-compacted areas, respectively. This difference was determined in both shallow and deep measuring ranges, indicating that the difference in soil compaction was detected in both topsoil and subsoil. Furthermore, the data was found to have a significant spatial variability, suggesting that, in order to detect the increase in EMI (which shows the increase in soil compaction), data within close surrounding area should be included in the analyses. Correlation coefficient of EMI and penetration resistance (average moisture content 32.5% and 30.8% for topsoil and subsoil) was found to be 0.66
Dirofilaria spp. And angiostrongylus vasorum: Current risk of spreading in central and northern europe
In the past few decades, the relevance of Dirofilaria immitis and Dirofilaria repens, causing cardiopulmonary and subcutaneous dirofilariosis in dogs and cats, and of Angiostrongylus vasorum, causing canine angiostrongylosis, has steadily increased in Central and Northern Europe. In this review, a summary of published articles and additional reports dealing with imported or autoch-thonous cases of these parasites is provided for Central (Austria, Czechia, Germany, Hungary, Lux-emburg, Poland, Slovakia, Slovenia, and Switzerland) and Northern (Denmark, Finland, Iceland, Norway, and Sweden) Europe. Research efforts focusing on Dirofilaria spp. and A. vasorum have varied by country, and cross-border studies are few. The housing conditions of dogs, pet move-ments, the spread of competent vectors, and climate change are important factors in the spread of these nematodes. Dogs kept outside overnight are a major factor for the establishment of Dirofilaria spp. However, the establishment of invasive, diurnal, synanthropic, competent mosquito vectors such as Aedes albopictus may also influence the establishment of Dirofilaria spp. The drivers of the spread of A. vasorum remain not fully understood, but it seems to be influenced by habitats shared with wild canids, dog relocation, and possibly climatic changes; its pattern of spreading appears to be similar in different countries. Both Dirofilaria spp. and A. vasorum merit further monitoring and research focus in Europe
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