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501.
Ilaria Torre 《User Modeling and User-Adapted Interaction》2009,19(5):433-486
In this paper we provide a classification of adaptive systems with respect to the kind of semantic technology they exploit
to accomplish or improve specific adaptation and user modeling tasks. This classification is based on a distinction between
strong semantic techniques and weak semantic techniques. The former are techniques based on the Semantic Web, while the latter regard technologies that, in different ways, annotate
resources, enriching their meaning. This second category includes, in particular, Web 2.0 social annotations and mixed approaches
between social annotations and Semantic Web techniques. While the impact of the Semantic Web on adaptive systems has been
discussed in several survey papers, the potential of weak semantic technologies has, so far, received little attention. The
aim of this analysis is to fill this gap. Therefore, we will discuss contributions and limits of both approaches, but we will
focus special attention on weak semantic adaptive systems. 相似文献
502.
An Empirical Study on the Reliability of Perceiving Correlation Indices using Scatterplots 下载免费PDF全文
Scatterplots have been in use for about two centuries, primarily for observing the relationship between two variables and commonly for supporting correlation analysis. In this paper, we report an empirical study that examines how humans’ perception of correlation using scatterplots relates to the Pearson's product‐moment correlation coefficient (PPMCC) – a commonly used statistical measure of correlation. In particular, we study human participants’ estimation of correlation under different conditions, e.g., different PPMCC values, different densities of data points, different levels of symmetry of data enclosures, and different patterns of data distribution. As the participants were instructed to estimate the PPMCC of each stimulus scatterplot, the difference between the estimated and actual PPMCC is referred to as an offset. The results of the study show that varying PPMCC values, symmetry of data enclosure, or data distribution does have an impact on the average offsets, while only large variations in density cause an impact that is statistically significant. This study indicates that humans’ perception of correlation using scatterplots does not correlate with computed PPMCC in a consistent manner. The magnitude of offsets may be affected not only by the difference between individuals, but also by geometric features of data enclosures. It suggests that visualizing scatterplots does not provide adequate support to the task of retrieving their corresponding PPMCC indicators, while the underlying model of humans’ perception of correlation using scatterplots ought to feature other variables in addition to PPMCC. The paper also includes a theoretical discussion on the cost‐benefit of using scatterplots. 相似文献
503.
E. Comini G. Faglia G. Sberveglieri L. Zanotti 《Materials and Manufacturing Processes》2006,21(3):229-232
Semiconducting oxide nanobelts have been obtained by vapor phase deposition. In this work we present the results obtained using tin oxide nanobelts as conductometric gas sensors. Electrical characterization showed that the nanobelts were sensitive to oxygen and environmental polluting species such as CO as well as ethanol for breath analyzers and food control applications. The sensor response, defined as the relative variation in conductance or resistance due to the introduction of the gas, is 200% for 30 ppm of CO at 623 K and 2500% for 10 ppm of ethanol at 623 K. We have studied the variation of the response as a function of the density of the nanobelts. The results demonstrate the potential of fabricating nanosize sensors using the integrity of a single nanobelt with sensitivity at the level of a few ppb and the necessity to control nanobelts density to optimize the sensing performances. 相似文献
504.
The general Poisson summation formula of Mellin analysis can be considered as a quadrature formula for the positive real axis with remainder. For Mellin bandlimited functions it becomes an exact quadrature formula. Our main aim is to study the speed of convergence to zero of the remainder for a function f in terms of its distance from a space of Mellin bandlimited functions. The resulting estimates turn out to be of best possible order. Moreover, we characterize certain rates of convergence in terms of Mellin–Sobolev and Mellin–Hardy type spaces that contain f. Some numerical experiments illustrate and confirm these results. 相似文献
505.
Andrea Ciavatti Laura Basiric Ilaria Fratelli Stefano Lai Piero Cosseddu Annalisa Bonfiglio John E. Anthony Beatrice Fraboni 《Advanced functional materials》2019,29(21)
The attention focused on the application of organic electronics for the detection of ionizing radiation is rapidly growing among the international scientific community, due to the great potential of organic technology to enable large‐area conformable sensor panels. However, high‐energy photon absorption is challenging as organic materials are constituted of atoms with low atomic numbers. Here it is reported how, by synthesizing new solution‐processable organic molecules derived from 6,13‐bis(triisopropylsilylethynyl)pentacene (TIPS‐pentacene) and 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl)anthradithiophene, with Ge‐substitution in place of the Si atoms to increase the material atomic number, it is possible to boost the X‐ray detection performance of organic thin films on flexible plastic substrates. Bis(triisopropylgermylethynyl)‐pentacene based flexible organic thin film transistors show high electrical performance with higher mobility (0.4 cm2 V?1 s?1) and enhanced X‐ray sensitivity, up to 9.0 × 105 µC Gy?1 cm?3, with respect to TIPS‐pentacene‐based detectors. Moreover, similar results are obtained for 5,11‐bis(triethylgermylethynyl)anthradithiophene devices, confirming that the proposed strategy, that is, increasing the atomic number of organic molecules by chemical tailoring to improve X‐ray sensitivity, can be generalized to organic thin film detectors, combining high X‐ray absorption, mechanical flexibility, and large‐area processing. 相似文献
506.
Tao Zhu Jun Su Jos Alvarez Grgory Lefvre Frdric Labat Ilaria Ciofini Thierry Pauport 《Advanced functional materials》2019,29(38)
The development of efficient photodetectors (PDs) for ultraviolet (UV) light is of great importance for many applications. In this paper, a novel approach is proposed for boosting the performances of self‐powered PDs. Visible‐blind UV‐A PDs are built by combining a mesoporous TiO2 layer with a Spiro‐OMeTAD layer. The nanostructured heterointerface is engineered by inserting a self‐assembled layer of organic modifiers. By choosing 4‐nitrobenzoic acid (NBA), the responsivity is boosted by 70% compared to the pristine devices. It achieves 64 mA W?1 at 0 V bias, 380 nm, and 1 mW cm?2. The PD displays a very high sensitivity (>104), a fast response time (<3 ms), a high stability, and repeatability. 4‐chlorobenzoic acid, 4‐methoxy benzoic acid, 4‐nitro benzoic acid, and β‐alanine surface modifiers are studied by a combined experimental and theoretical approach. Their dipole moment is calculated. Their presence induces a step in the vacuum energy and the formed dipole field dramatically affects the charge transfer and then the photocurrent/photoresponse of the device. The higher responsivity of the NBA‐modified PD is thus explained by the better and faster electron charge transfer toward the electrical contact on TiO2. 相似文献
507.
Elena De Marco Maria Savarese Cristina Parisini Ilaria Battimo Salvatore Falco Raffaele Sacchi 《European Journal of Lipid Science and Technology》2007,109(3):237-246
The aim of this study was to test the performance of a vegetable oil blend formulated as alternative to pure palm oil as frying medium. For this purpose, the evolution of many analytical parameters (free acidity, spectrophotometric indices, total polar components, fatty acid composition, short‐chain fatty acids, tocopherol and tocotrienol content and composition, color, flavor evaluated by means of an electronic nose) of the selected blend (sunflower/palm oil 65 : 35 vol/vol) has been monitored during a prolonged frying process (8 h discontinuous frying without oil replenishment) in comparison to pure palm oil. Sensory attributes of the fried food were also evaluated. The blend proved to keep qualitative parameters comparable to those shown by palm oil during the prolonged frying process. Even if some oxidation indices, such as spectrophotometric indices, short‐chain fatty acids and total polar components, increased faster in the blend, it showed a higher tocopherol content and a lower increment in free fatty acids as compared to pure palm oil. Chips fried in the two oils did not show significantly different sensory profiles. 相似文献
508.
We address the question of typing noninterference (NI) in the calculus CCS, in such a way that Milner's translation into CCS of a standard parallel imperative language preserves both an existing NI property and the associated type system. Recently, Focardi, Rossi and Sabelfeld have shown that a variant of Milner's translation, restricted to the sequential fragment of the language, maps a time-sensitive NI property to that of Persistent Bisimulation-based Non Deducibility on Compositions (PBNDC) on CCS. However, since CCS was not equipped with a type system, the question of whether the translation preserves types could not be addressed. We extend Focardi, Rossi and Sabelfeld's result by showing that a slightly simpler variant of Milner's translation preserves a time-insensitive NI property on the full parallel language, by mapping it again to PBNDC. As a by-product, we formalise a folklore result, namely that Milner's translation preserves a behavioural equivalence on programs. We present a simple type system ensuring PBNDC on CCS, inspired by existing type systems for the π-calculus. Unfortunately, this type system as it stands is too restrictive to grant the expected type preservation result. We sketch a solution to overcome this problem. 相似文献
509.
Ilaria Papa Antonio Langella Valentina Lopresto 《Polymer Engineering and Science》2019,59(12):2429-2437
In this work, carbon fiber‐reinforced composites (CFRP), respectively, based on a vynilester and epoxy resin were loaded under low‐velocity impact condition to highlight the influences of different matrices and temperature on their dynamic response. In particular, measurements were performed at room and the low temperature of ?25°C on samples simply supported by air to exactly simulate the incidental impact during the structure service and having the same thickness. Impact tests were carried out at penetration to obtain the complete load–displacement curve and to measure the penetration energy, and at different energy levels, 5, 10, and 20 J, to investigate the influence of the matrix on the damage start and propagation. After the impact tests, the specimens were nondestructively investigated by the ultrasound technique to measure the delamination. The interesting results obtained on carbon fiber laminates impacted at room and lower temperature are here reported and compared. In general, better behavior was noted for vinyl ester‐based composites, extensively used in the naval field, thanks to their low absorption for humidity. POLYM. ENG. SCI., 59:2429–2437, 2019. © 2019 Society of Plastics Engineers 相似文献
510.
Synthetic hydroxyapatites incorporating small amounts of Si have shown improved biological performances in terms of enhanced bone apposition, bone in-growth and cell-mediated degradation.This paper reports a systematic investigation on Si-substituted hydroxyapatite (Si 1.40 wt%) nanopowders produced following two different conventional wet methodologies: (a) precipitation of Ca(NO3)2·4H2O and (b) titration of Ca(OH)2. The influence of the synthesis process on composition, thermal behaviour and sinterability of the resulting nanopowders is studied.Samples were characterised by electron microscopy, induced coupled plasma atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N2 adsorption measurements, X-ray diffraction and dilatometry. Semicrystalline Si-substituted hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 84 and 110 m2/g. Pure and Si-substituted hydroxyapatite nanopowders derived from Ca(NO3)2·4H2O decomposed around 1000 °C. Si-substituted hydroxyapatite nanopowders obtained from Ca(OH)2 were thermally stable up to 1200 °C and showed a distinct decreased thermal stability with respect to the homologous pure sample. Si-substituted hydroxyapatites exhibited higher sintering temperature and increased total shrinkage with respect to pure powders. Nanostructured dense ceramics were obtained by sintering at 1100 °C Si-substituted hydroxyapatites derived from Ca(OH)2. 相似文献