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111.
Nicola Barbieri Giuseppe Manco Ettore Ritacco Marco Carnuccio Antonio Bevacqua 《Machine Learning》2013,93(1):5-29
Probabilistic topic models are widely used in different contexts to uncover the hidden structure in large text corpora. One of the main (and perhaps strong) assumption of these models is that generative process follows a bag-of-words assumption, i.e. each token is independent from the previous one. We extend the popular Latent Dirichlet Allocation model by exploiting three different conditional Markovian assumptions: (i) the token generation depends on the current topic and on the previous token; (ii) the topic associated with each observation depends on topic associated with the previous one; (iii) the token generation depends on the current and previous topic. For each of these modeling assumptions we present a Gibbs Sampling procedure for parameter estimation. Experimental evaluation over real-word data shows the performance advantages, in terms of recall and precision, of the sequence-modeling approaches. 相似文献
112.
Jony Javorski Eckert Ludmila Corrêa de Alkmin e Silva Fabio Mazzariol Santiciolli Eduardo dos Santos Costa Fernanda Cristina Corrêa Franco Giuseppe Dedini 《国际能源研究杂志》2018,42(11):3506-3523
Two big issues involving electric vehicles are energy supply and power management control. To deal with the energy supply problem, this paper proposes the application of a hybrid energy source system, composed of battery pack and ultracapacitor bank. The power management control between the energy supplies was defined by a fuzzy logic with inference rules optimized through genetic algorithm. The genetic algorithm optimizes lower and upper limits of membership functions aiming to reduce the hybrid energy source system total mass while maximizing the electric vehicle drive range and performance. Through the Pareto frontier, we found the best trade‐off solution. 相似文献
113.
114.
Giuseppe Diglio Piero Bareschino Erasmo Mancusi Francesco Pepe 《International Journal of Hydrogen Energy》2017,42(22):15010-15023
This paper presents a novel quasi-autothermal hydrogen production process. The proposed layout couples a Chemical Looping Combustion (CLC) section and a Steam Methane Reforming (SMR) one. In CLC section, four packed-beds are operated using Ni as oxygen carrier and CH4 as fuel to continuously produce a hot gaseous mixture of H2O and CO2. In SMR section, two fixed-beds filled with Ni-based catalyst convert CH4 and H2O into a H2-rich syngas. Four heat exchangers were employed to recover residual heat content of all the exhaust gas currents. By means of a previously developed 1D numerical model, a dynamic simulation study was carried out to evaluate feasibility of the proposed system in terms of methane conversion (100% circa), hydrogen yield (about 0.65 molH2/molCH4) and selectivity (about 70%), and syngas ratio (about 2.3 molH2/molCO). Energetic and environmental analyses of the system performed with respect to conventional steam methane reforming, highlights an energy saving of about 98% and avoided CO2 emission of about 99%. 相似文献
115.
Giuseppe Colla Youssef Rouphael Mariateresa Cardarelli Eva Svecova Elvira Rea Luigi Lucini 《Journal of the science of food and agriculture》2013,93(5):1119-1127
BACKGROUND: Cynara cardunculus is a species native to the Mediterranean basin. It includes globe artichoke and cultivated cardoon as well as their progenitor wild cardoon. The species is a source of biophenols, and its leaf extracts have been widely used in herbal medicine as hepatoprotectors and choleretics since ancient times. The aim of this study was to determine the effect of increasing the level of salinity in the nutrient solution (1 or 30 mmol L?1 NaCl) on biomass production, mineral composition, radical‐scavenging activity, caffeoylquinic acids and flavonoids in three artichoke (‘Romolo’, ‘Violetto di Provenza’ and ‘Violetto di Romagna’) and three cultivated cardoon (‘Bianco Avorio’, ‘Bianco Gigante Inerme’ and ‘Gigante di Romagna’) cultivars grown in a floating system. RESULTS: Increased salinity in the nutrient solution decreased the leaf dry biomass and leaf number of artichoke and cultivated cardoon cultivars. Salinity reduced macro‐ and microelement accumulation in leaves (e.g. N, K, Ca, Mg, Fe, Mn and B) but improved their antioxidant activity, total polyphenols, chlorogenic acid, cynarin and luteolin. The cultivated cardoons, especially ‘Bianco Avorio’ and ‘Gigante di Romagna’, showed higher biomass and leaf number than those observed in artichoke genotypes. ‘Violetto di Provenza’ exhibited the highest content of chlorogenic acid, closely followed by ‘Violetto di Romagna’, whereas for cynarin content the highest values were recorded in ‘Violetto di Provenza’, ‘Bianco Avorio’ and ‘Gigante di Romagna’. The highest content of luteolin was recorded in ‘Gigante di Romagna’ and ‘Bianco Avorio’, while the highest content of apigenin was observed in ‘Gigante di Romagna’. CONCLUSION: The results showed that the floating system could be considered an effective tool to improve quality aspects through proper management of the salt concentration in the nutrient solution. They also suggest that specific cultivars should be selected to obtain the desired profile of bioactive compounds. © 2012 Society of Chemical Industry 相似文献
116.
Melissa Infusino Antonio De Luca Federica Ciuchi Andrei Ionescu Nicola Scaramuzza Giuseppe Strangi 《Journal of Materials Science》2014,49(4):1805-1811
We report on the effect of gold nanoparticle (Au NP) dispersion in a chiral nematic liquid crystal (LC). Polarized optical microscopy and X-ray diffraction measurements evidence the insurgence of an order change in the LC host. Moreover, a comparative analysis based on dielectric and voltammetric spectroscopies performed on pure LC and on Au NP-doped LC shows that Au NP’s presence besides affecting LC order influences its electric properties: ion conductivity results importantly reduced, and beyond a threshold value of the applied field electrophoresis phenomena are induced. 相似文献
117.
Giuseppe Espa Danila Filipponi Diego Giuliani Davide Piacentino 《Papers in Regional Science》2014,93(Z1):S113-S135
In this paper, spatial shift‐share decomposition is analysed when applied to Italian data on regional business change at plant level, over the period 2004–2009. A new type of spatial decomposition, which looks more effectively at neighbourhood influence, is introduced here. Notable results emerge from the empirical investigation. First, it can be seen that the spatial level of aggregation greatly affects results. Second, evidence of neighbourhood advantage in the Southern NUTS 3 regions is found, together with opposite results for the Central‐Northern NUTS 3 regions. Finally, evidence of positive industrial mix effects is only found in Central‐Northern Italy. 相似文献
118.
Antonella De Leonardis Giuseppe Lustrato Vincenzo Macciola Giancarlo Ranalli 《European Food Research and Technology》2010,231(4):603-610
Several chemical and physical anti-browning agents are studied in different model systems in which caffeic acid (as substrate)
and laccase from Trametes versicolor (LAC) and polyphenoloxidase from sunflower seeds (PPO) (as enzymes) are used to emulate the browning reaction. Temperature
and low electric current were the tested physical agents, while acetic acid, sodium acetate, sodium chloride and, finally,
sodium bisulfite were the chemical agents. Sunflower PPO was observed to be less heat sensitive than LAC that was fully inactivated
after 1 and 3 min of exposure to 100 and 80 °C, respectively. Conversely, PPO required more than 3 min at 100 °C to be fully
inactivated, and it still showed a significant activity (ca. 17%) after an exposure to 80 °C for 15 min. Both LAC and PPO
were found to be active at frozen (−18 °C) and cool (+4 °C) temperature, and their activities were strengthened at 40 and
60 °C. As concerning chemical agents, inhibitory power of acetic acid on LAC was observed to be very weak. In the sodium acetate
solution at the concentrations of 0.5, 1.0, 2.0 and 4.0%, LAC residual activity was equal to 81.5, 63.9, 61.1 and 35.2%, respectively.
PPO is shown to be more sensitive to the NaCl than LAC and indifferent to the presence of NaHSO3. A 28% residual activity of LAC was found in the solution with 200 mg L−1 NaHSO3. Finally, LAC activity was decreased to 72.3, 60.0, 16.7 and 8.4% after a low electric current (LEC) treatment of 30 s and
1, 3 and 6 min, respectively. Conversely, PPO activity was not affected under these conditions. 相似文献
119.
The technical quality of two compositionally different groups of solid bricks fired between 800 and 1000 °C was evaluated. Five weight percentage of fly ash was added to both groups and they were compared with similar bricks with no added fly ash.The textures of the bricks with fly ash were very similar to the textures of those without it, except that the samples with the additive contained spherical fly ash particles with diameters ranging from 0.1 to 10 μm. These particles led to a reduction in the density of the bricks and a substantial improvement in their durability, with less decay being caused by salt crystallization in the pores. This is because fly ash causes a reduction in the number of micropores, the pores that make porous materials most vulnerable to salt-induced decay. Use of this additive could have practical implications as a means of recycling and for achieving cost savings in brick production. 相似文献
120.
High‐tuning‐range CMOS band‐pass IF filter based on a low‐Q cascaded biquad optimization technique 下载免费PDF全文
Pietro Monsurrò Salvatore Pennisi Giuseppe Scotti Alessandro Trifiletti 《International Journal of Circuit Theory and Applications》2015,43(11):1615-1636
A design procedure for high‐order continuous‐time intermediate‐frequency band‐pass filters based on the cascade of low‐Q biquadratic cells is presented. The approach is well suited for integrated‐circuit fabrication, as it takes into account the maximum capacitance spread dictated by the available technology and maximum acceptable sensitivity to component variations. A trade‐off between noise and maximum linear range is also met. A novel, wide‐tuning‐range transconductor topology is also described. Based on these results, a 10‐pole band‐pass filter for a code division multiple‐access satellite receiver has been designed and tested. The filter provides tunable center frequency (f0) from 10 to 70 MHz and exhibits a 28‐MHz bandwidth around f0 = 70 MHz with more than 39‐dB attenuation at f0/2 and 2f0. Third‐order harmonic rejection is higher than 60 dB for a 1‐Vpp 70‐MHz input, and equivalent output noise is lower than 1 mVrms. The circuit is fabricated in a 0.25‐µm complementary metal oxide semiconductor process, and the core consumes 12 mA from a 2.5‐V supply, offering the best current/pole ratio figure. The die area resulted to be 0.9 × 1.1 mm2. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献