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排序方式: 共有2337条查询结果,搜索用时 31 毫秒
51.
52.
Jordan Navarro Elsa Yousfi Jonathan Deniel Christophe Jallais Mercedes Bueno Alexandra Fort 《Ergonomics》2016,59(12):1553-1564
In the past, lane departure warnings (LDWs) were demonstrated to improve driving behaviours during lane departures but little is known about the effects of unreliable warnings. This experiment focused on the influence of false warnings alone or in combination with missed warnings and warning onset on assistance effectiveness and acceptance. Two assistance unreliability levels (33 and 17%) and two warning onsets (partial and full lane departure) were manipulated in order to investigate interaction. Results showed that assistance, regardless unreliability levels and warning onsets, improved driving behaviours during lane departure episodes and outside of these episodes by favouring better lane-keeping performances. Full lane departure and highly unreliable warnings, however, reduced assistance efficiency. Drivers’ assistance acceptance was better for the most reliable warnings and for the subsequent warnings. The data indicate that imperfect LDWs (false warnings or false and missed warnings) further improve driving behaviours compared to no assistance.
Practitioner Summary: This study revealed that imperfect lane departure warnings are able to significantly improve driving performances and that warning onset is a key element for assistance effectiveness and acceptance. The conclusion may be of particular interest for lane departure warning designers. 相似文献
53.
54.
Mu’awya NaserPedro Peris-Lopez Rahmat BudiartoBenjamín Ramos Álvarez 《Computer Communications》2011,34(18):2248-2249
In this letter, we analyze the security of an RFID authentication protocol proposed by Liu and Bailey [1], called privacy and authentication protocol (PAP). We present two traceability attacks and an impersonation attack. 相似文献
55.
Extensive research has been carried out in multiresolution models for many decades. The tendency in recent years has been
to harness the potential of GPUs to perform the level-of-detail extraction on graphics hardware. The aim of this work is to
present a new level-of-detail scheme based on triangles which is both simple and efficient. In this approach, the extraction
process updates vertices instead of indices, thus providing a perfect framework for adapting the algorithms to work completely
on GPU shaders. One of the key aspects of our proposal is the need for just a single rendering pass in order to obtain the
desired geometry. Moreover, coherence among the different approximations is maximized by means of a symmetric extraction algorithm,
which performs the same process when refining and coarsening the mesh. Lastly, we also introduce different uses of the scheme
to offer continuous and view-dependent resolution. 相似文献
56.
Mortar mixes with different water-cement ratios and consistency were impregnated with methyl-methacrylate monomer and polymerized thermally under water using the free radical initiator, -azobis (isobutyronitrile). Results on drying, impregnation and polymerization are presented. It is shown that a considerable amount of polymer remained strongly adhered or chemically inserted in the inorganic matrix. The molecular weight of the inserted polymer is higher than that obtained in the solvent extracted polymer and this is also higher than the polymer molecular weight obtained by bulk polymerization under the same conditions. The compressive and flexural strength of the impregnated mortar were found to be a function of the amount of polymer in the composites. Fracture behaviour under load, and polymer distribution inside the composites were examined by scanning electron microscopic techniques (SEM). It was observed that the polymer acts in two ways, first as a filler of porous and microcrack voids, secondly forming an anisotropic irregular network improving the bond characteristic of the interface between aggregate and matrix. Furthermore, due to the the adhesion of the polymer to both phases, it acts as a reinforcement and improves the mechanical properties, in particular the flexural strength. 相似文献
57.
Armando Carravetta Giuseppe Del Giudice Oreste Fecarotta Helena M. Ramos 《Water Resources Management》2012,26(13):3947-3959
Pump operating as turbine (PAT) is an effective source of reducing the equipment cost in small hydropower plants. However, the manufacturers provide poor information on the PAT performance thus representing a limit for its wider diffusion. Additional implementation difficulties arise under variable operating conditions, characteristic of water distribution networks (WDNs). WDNs allow to obtain widespread and globally significant amount of produced energy by exploiting the head drop due to the network pressure control strategy for leak reductions. Thus a design procedure is proposed that couples a parallel hydraulic circuit with an overall plant efficiency criteria for the market pump selection within a WDN. The proposed design method allows to identify the performance curves of the PAT that maximizes the produced energy for an assigned flow and pressure-head distribution pattern. Finally, computational fluid dynamics (CFD) is shown as a suitable alternative for performance curve assessment covering the limited number of experimental data. 相似文献
58.
In this work the anaerobic monodigestion for the treatment of turkey manure was evaluated, without its codigestion with another substrate. The effect of the organic loading rate (OLR) and the substrate concentration (high total solids (TS) concentration) or product concentration (high volatile fatty acids (VFA) and/or ammonia (NH(3)-N) concentrations) was studied. The results show that for a continuous stirred tank reactor (CSTR) operation, a maximum of 40 g/L of TS and 4.0 g/L of ammonium (NH(4)(+)) was required. In addition, the maximum organic loading rate (OLR) will not exceed 1.5 kg VS/m(3)d. Higher TS and NH(4)(+) concentrations and OLR lead to a reduction on the methane productivity and volatile solids (VS) removal. During the CSTR operation, a high alkalinity concentration (above 10 g/L CaCO(3)) was found; this situation allowed maintaining a constant and appropriate pH (close to 7.8), despite the VFA accumulation. In this sense, the alkalinity ratio (α) is a more appropriate control and monitoring parameter of the reactor operation compared to pH. Additionally, with this parameter a VS removal of 80% with a methane productivity of 0.50 m(3)(CH4)/m(3)(R)d is achieved. 相似文献
59.
M.P.M.A. Baroni R.R. Rosa I. Pepe F.M. Ramos C. Persson 《Microelectronics Journal》2006,37(4):290-294
Technological applications in opto-electronic devices have increased the interest in characterizing porous silicon structure patterns. Due to its physical properties, solutions from KPZ 2D are adopted to simulate the structure of porous material interface whose spatial characteristics are equivalent to those found in porous silicon samples. The analysis of the simulated and real Scanning Force Microscopy (SFM) surfaces was done using the Gradient Pattern Analysis (GPA). We found that the KPZ 2D model presented asymmetry levels compatible with the irregular surfaces observed by means of SFM images of π-Si. 相似文献
60.
R. Sánchez-Pérez L. García-Demedices J. Palafox Ramos M. Díaz-Cruz R. D. Morales 《Metallurgical and Materials Transactions B》2004,35(1):85-99
Two-phase flows in a mold of a slab caster are studied using water modeling, particle-image velocimetry (PIV), and computational
fluid-dynamics techniques. Two-way coupled flows are observed in liquidgas systems, because both phases influence each other’s
momentum transfer. In addition to this concept, PIV measurements indicate the existence of structurally coupled flows, where
the velocity vectors of both phases observe similar orientations. When the drag forces of the liquid, exerted on the bubbles,
exceed a certain value of the inertial forces of the liquid phase, at high mass loads of gas (ratio of mass flow rates of
the gas phase and the liquid phase), the flow becomes structurally coupled. These types of flows promote large oscillations
of the meniscus level. Two jets, liquid and bubble, were identified; the latter always reported larger angles than the first,
independent of the gas load. Thus, a gas-rich jet is located closer to the lower edge of the submerged entry nozzle (SEN)
port, and the liquid-rich jet is found above this position. The liquid-jet angle approaches that of the SEN port when the
flow becomes structurally coupled. Structurally uncoupled flows report gas jets that follow torrent-type patterns which are
well explained using a multiphase fluid-dynamics model. Structurally coupled flows yield gas jets with a continuous pattern. 相似文献