140 research outputs found
INSIDES â A new Virtual Prototyping Platform of Human Machine Interactions Systems for Automotive and Aerospace Applications
International audienceHuman Machine Interactions Systems are decisive for the acceptance and the safety of new cockpits in the automotive as well as in the aerospace industries. A new design and simulation platform called INSIDES will be presented where virtual cockpit prototypes are being built based on 3D CAD geometry e.g. from CATIA and integrated with logical interaction data derived from UML specifications. This new development platform enables the continuous validation and check of new interaction concepts by involving usability engineers in the very early stage of the development cycle. Since the simulation work is being done in the context of the entire aircraft cockpit/car interior with all instruments, control commands as well displays devices a better validation of the HMI systems can be achieved
Higher-order contributions to the Rashba-Bychkov effect with application to Bi/Ag(111) surface alloy
In order to explain the anisotropic Rashba-Bychkov effect observed in several
metallic surface-state systems, we use k.p perturbation theory with a simple
group-theoretical analysis and construct effective Rashba Hamiltonians for
different point groups up to third order in the wavenumber. We perform
relativistic ab initio calculations for the Bi/Ag(111) ordered surface alloy
and from the calculated splitting of the band dispersion we find evidence of
the predicted third-order terms. Furthermore, we derive expressions for the
corresponding third-order Rashba parameters to provide a simple explanation to
the qualitative difference concerning the Rashba-Bychkov splitting of the
surface states at Au(111) and Bi/Ag(111).Comment: 7 pages, 3 figure
Analytical drainâcurrent model of pâ and nâchannel OTFTs for circuit simulation
Organic thin-film transistors (OTFTs) are an emerging technology for large scale circuit integration, owing the availability of both p- and n- channel devices. For the technology development and the design of circuits and digital systems, the accurate physical modeling is mandatory. In this work we propose an unified analytical model for both p- and n- type OTFTs. The model is physically based and accounts for a double exponential density of states (DOS). It is simple, symmetric and accurately describes the below-threshold, linear, and saturation regimes via a unique formulation. The model is eventually validated with the measurements of complementary OTFTs fabricated in a fullyprinted technolog
Dynamics of conflicts in Wikipedia
In this work we study the dynamical features of editorial wars in Wikipedia
(WP). Based on our previously established algorithm, we build up samples of
controversial and peaceful articles and analyze the temporal characteristics of
the activity in these samples. On short time scales, we show that there is a
clear correspondence between conflict and burstiness of activity patterns, and
that memory effects play an important role in controversies. On long time
scales, we identify three distinct developmental patterns for the overall
behavior of the articles. We are able to distinguish cases eventually leading
to consensus from those cases where a compromise is far from achievable.
Finally, we analyze discussion networks and conclude that edit wars are mainly
fought by few editors only.Comment: Supporting information adde
Adiabatic perturbation theory and geometry of periodically-driven systems
We give a systematic review of the adiabatic theorem and the leading non-adiabatic corrections in periodically-driven (Floquet) systems. These corrections have a two-fold origin: (i) conventional ones originating from the gradually changing Floquet Hamiltonian and (ii) corrections originating from changing the micro-motion operator. These corrections conspire to give a Hall-type linear response for non-stroboscopic (time-averaged) observables allowing one to measure the Berry curvature and the Chern number related to the Floquet Hamiltonian, thus extending these concepts to periodically-driven many-body systems. The non-zero Floquet Chern number allows one to realize a Thouless energy pump, where one can adiabatically add energy to the system in discrete units of the driving frequency. We discuss the validity of Floquet Adiabatic Perturbation Theory (FAPT) using five different models covering linear and non-linear few and many-particle systems. We argue that in interacting systems, even in the stable high-frequency regimes, FAPT breaks down at ultra slow ramp rates due to avoided crossings of photon resonances, not captured by the inverse-frequency expansion, leading to a counter-intuitive stronger heating at slower ramp rates. Nevertheless, large windows in the ramp rate are shown to exist for which the physics of interacting driven systems is well captured by FAPT.The authors would like to thank M. Aidelsburger, M. Atala, E. Dalla Torre, N. Goldman, M. Heyl, D. Huse, G. Jotzu, C. Kennedy, M. Lohse, T. Mori, L. Pollet, M. Rudner, A. Russomanno, and C. Schweizer for fruitful discussions. This work was supported by AFOSR FA9550-16-1-0334, NSF DMR-1506340, ARO W911NF1410540, and the Hungarian research grant OTKA Nos. K101244, K105149. M. K. was supported by Laboratory Directed Research and Development (LDRD) funding from Berkeley Lab, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The authors are pleased to acknowledge that the computational work reported in this paper was performed on the Shared Computing Cluster which is administered by Boston University's Research Computing Services. The authors also acknowledge the Research Computing Services group for providing consulting support which has contributed to the results reported within this paper. The study of the driven non-integrable transverse-field Ising model was carried out using QuSpin [185] - an open-source state-of-the-art Python package for dynamics and exact diagonalization of quantum many body systems, available to download here. (FA9550-16-1-0334 - AFOSR; DMR-1506340 - NSF; W911NF1410540 - ARO; K101244 - Hungarian research grant OTKA; K105149 - Hungarian research grant OTKA; DE-AC02-05CH11231 - Laboratory Directed Research and Development (LDRD) funding from Berkeley Lab)https://arxiv.org/pdf/1606.02229.pd
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How values and perceptions shape farmers' biodiversity management: insights from ten European countries
Farmers play a pivotal role in addressing biodiversity loss whilst maintaining food production. To rethink
conservation in agricultural landscapes, it is crucial to understand their decisions regarding biodiversity and its
management on the farms. In this study, we conducted 48 semi-structured interviews across ten European
countries in 2021/22 to explore how farmersâ perceptions and valuations relate to their biodiversity management. Employing reflexive thematic analysis, we identified recurring patterns of shared meanings. Our findings
underscore the profound influence of farmersâ biodiversity perceptions on their biodiversity management
practices: 1) Narrow and targeted interventions were closely tied to instrumental values of biodiversity, whereas
holistic management strategies were linked with recognising an inherent value of nature. 2) Targeted approaches
were related to farmersâ interpretations of biodiversity as specific taxa and functions, relying on easily assessable
and emotionally connoted indicators. 3) Holistic approaches aligned with a broader biodiversity concept and an
emphasis on intricate functional relationships within ecosystems. 4) Actual decisions to implement measures
were significantly constrained by perceived dependencies, namely production pathways, social dependencies,
and landscape conditions. These findings raise a critical question about the prioritisation of ecocentric intrinsic
versus anthropocentric instrumental values in conservation strategies. We propose an approach of ethical
pluralism, acknowledging that instrumental values may provide practical solutions for certain challenges, while
intrinsic values hold ethical significance, particularly in the context of complex or large-scale biodiversity
conservation initiatives. Engaging in dialogue that accounts for diverse values will be essential for shaping
effective and socially meaningful biodiversity conservation
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Seminatural areas act as reservoirs of genetic diversity for crop pollinators and natural enemies across Europe
Despite increasing recognition of the importance of the multiple dimensions of biodiversity, including functional or genetic diversity as well as species diversity, most conservation studies on ecosystem service-providing insects focus on simple diversity measures such as species richness and abundance. In contrast, relatively little is known about the genetic diversity and resilience of pollinators or natural enemies of crop pests to population fragmentation and local extinction. The genetic diversity and demographic dynamics of remnant populations of beneficial insects in agricultural areas can be a useful indicator proving additional insights into their conservation status, but this is rarely evaluated. Although gene flow between agricultural and seminatural areas is key to maintaining genetic diversity, its extent and directionality remain largely unexplored. Here, we apply a pan-European sampling protocol to quantify genetic diversity and structure and assess gene flow between agricultural and nearby seminatural landscapes in populations of two key ecosystem service-providing insect species, the lady beetle Coccinella septempunctata, an important predator of aphids and other crop pests, and the bee pollinator Andrena flavipes. We show that A. flavipes populations are genetically structured at the European level, whereas populations of C. septempunctata experience widespread gene flow across the continent and lack any defined genetic structure. In both species, we found that there is high genetic connectivity between populations established in croplands and nearby seminatural areas and, as a consequence, they harbor similar levels of genetic diversity. Interestingly, demographic models for some regions support asymmetric gene flow from seminatural areas to nearby agricultural landscapes. Collectively, our study demonstrates how seminatural areas can serve as genetic reservoirs of both pollinators and natural enemies for nearby agricultural landscapes, acting as sources for recurrent recolonization and, potentially, contributing to enhancing ecosystem service and crop production resilience in the longer term
Towards colloidal spintronics through Rashba spin-orbit interaction in lead sulphide nanosheets
Employing the spin degree of freedom of charge carriers offers the
possibility to extend the functionality of conventional electronic devices,
while colloidal chemistry can be used to synthesize inexpensive and tuneable
nanomaterials. In order to benefit from both concepts, Rashba spin-orbit
interaction has been investigated in colloidal lead sulphide nanosheets by
electrical measurements on the circular photo-galvanic effect. Lead sulphide
nanosheets possess rock salt crystal structure, which is centrosymmetric. The
symmetry can be broken by quantum confinement, asymmetric vertical interfaces
and a gate electric field leading to Rashba-type band splitting in momentum
space at the M points, which results in an unconventional selection mechanism
for the excitation of the carriers. The effect, which is supported by
simulations of the band structure using density functional theory, can be tuned
by the gate electric field and by the thickness of the sheets. Spin-related
electrical transport phenomena in colloidal materials open a promising pathway
towards future inexpensive spintronic devices.Comment: 25 pages, 4 figure
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Using a perception matrix to elicit farmersâ perceptions towards stakeholders in the context of biodiversity-friendly farming
Farmers' pro-environmental action is substantially influenced by various stakeholders from their business and social environment. Recent studies recommend actively involving influential stakeholders in agri-environmental initiatives, information or media campaigns. While it has been argued that farmers' perceptions towards these stakeholders can help inform effective involvement, comprehensive assessments of these perceptions remain scarce, particularly in the context of biodiversity-friendly farming. To understand and compare farmersâ perceptions of these stakeholder quantitatively, we developed and applied a perception matrix. In an exploratory survey with 49 farmers across ten European countries, farmers rated twelve groups of stakeholders (e.g. government bodies, farm advisors and input suppliers) against eight perception constructs (e.g. trustworthiness, interest in protecting biodiversity). We found that perceptions differed significantly both between groups of stakeholders and between constructs. Whereas several stakeholders were, on average, perceived positively regarding their general characteristics, such as trustworthiness, reliability, understanding and support for farming, perceptions regarding their biodiversity-related behavior were significantly more negative. Our findings indicate potential to improve policy development and implementation of agri-environmental initiatives through the involvement of multiple, non-governmental, agricultural and non-agricultural stakeholders in biodiversity-friendly farming initiatives across the entire agri-food value chain. Such multi-stakeholder initiatives could help to not only reinforce biodiversity conservation action among the farming community, but across society as a whole as emphasized by the Convention on Biological Diversity. Further research is needed to confirm the observed trends on a larger, representative sample, for which the presented perception matrix is well suited
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