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1.
In order to be capable of exploiting context for pro-active information recommendation, agents need to extract and understand
user activities based on their knowledge of the user interests. In this paper, we propose a novel approach for context-aware
recommendation in browsing assistants based on the integration of user profiles, navigational patterns and contextual elements.
In this approach, user profiles built using an unsupervised Web page clustering algorithm are used to characterize user ongoing
activities and behavior patterns. Experimental evidence show that using longer-term interests to explain active browsing goals
user assistance is effectively enhanced.
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Analía AmandiEmail: |
2.
Ontology-based user profile learning 总被引:4,自引:4,他引:0
Personal agents gather information about users in a user profile. In this work, we propose a novel ontology-based user profile
learning. Particularly, we aim to learn context-enriched user profiles using data mining techniques and ontologies. We are
interested in knowing to what extent data mining techniques can be used for user profile generation, and how to utilize ontologies
for user profile improvement. The objective is to semantically enrich a user profile with contextual information by using
association rules, Bayesian networks and ontologies in order to improve agent performance. At runtime, we learn which the
relevant contexts to the user are based on the user’s behavior observation. Then, we represent the relevant contexts learnt
as ontology segments. The encouraging experimental results show the usefulness of including semantics into a user profile
as well as the advantages of integrating agents and data mining using ontologies. 相似文献
3.
Analía V. Gómez Cristina Ferrero Cecilia Puppo Carmen C. Tadini Analía G. Abraham 《International Journal of Food Science & Technology》2014,49(10):2315-2322
The objectives of this research were to study the effect of the addition of lyophilised kefir milk to premixes for household production of bread and evaluate the quality attributes of them. Four lyophilised samples were obtained from the followings: skim milk, acidified skim milk, fermented skim milk and neutralised fermented skim milk. Breads were prepared with commercial wheat flour, lyophilised milk samples and yeast through a straight dough process. Quality was assessed through loaf volume, crumb porosity and moisture, crumb texture and crust colour. Changes in texture and starch recrystallisation by X‐ray diffractometry were determined after 1 and 3 days of storage at room temperature. Breads with acidified milks showed the highest specific volumes and crumbs with the best texture properties. Crystallinity in bread with fermented milks was higher than for skim milk sample. This would indicate that there would be a certain effect of the type of milk processing on the promotion of starch retrogradation. 相似文献
4.
Upender Gangadharini Atiar Rahaman Molla Anal Tarafder Basudeb Karmakar 《Journal of the American Ceramic Society》2013,96(7):2155-2162
The glass–ceramics containing a rarely achievable nanocrystalline SrIINbIVO3 phase in the 53.75SiO2–18.25K2O–9Bi2O3–9SrO–9Nb2O5–0.5CeO2–0.5Eu2O3 (mol%) glass system were prepared by the melt‐quench technique followed by a two‐stage controlled heat treatment. The unusual oxidation state of Nb in SrIINbIVO3 crystal is 4+ and upon heat treatment of the samples at lower temperature of 500°C for several hours, the glass composition and chemical environment around Nb ions played a key role for the formation of SrIINbIVO3 in the glass–ceramics. The microstructure of the glass–ceramics was studied using TEM and FESEM. The TEM images advocate 10–40 nm crystallite size of SrIINbIVO3. FTIR study confirms that all the samples consist of SiO4, BiO3, BiO6, and NbO6 structural units. The refractive index at different wavelengths was found to vary in the range 1.7105–1.7905 and increase with increase in heat‐treatment time. The luminescence spectra of Eu3+‐doped glass and glass–ceramics were recorded at 465 nm excitation wavelength and the luminescence intensity is found to be increased with heat‐treatment time due to increase in crystallinity. The high intensity ratio of 5D0→7F2 to 5D0→7F1 indicates that the Eu3+‐doped nanocrystalline SrIINbIVO3 glass–ceramics are promising candidate materials as red‐light source. 相似文献
5.
Anal Tarafder Atiar Rahaman Molla Chirantan Dey Basudeb Karmakar 《Journal of the American Ceramic Society》2013,96(8):2424-2431
The precursor glass in the ZnO–Al2O3–B2O3–SiO2 (ZABS) system doped with Eu2O3 was prepared by the melt‐quench technique. The transparent willemite, Zn2SiO4 (ZS) glass–ceramic nanocomposites were derived from this precursor glass by a controlled crystallization process. The formation of willemite crystal phase, size, and morphology with increase in heat‐treatment time was examined by X‐ray diffraction (XRD) and field‐emission scanning electron microscopy (FESEM) techniques. The average calculated crystallite size obtained from XRD is found to be in the range 18–70 nm whereas the grain size observed in FESEM is 50–250 nm. The refractive index value is decreased with increase in heat‐treatment time which is caused by the partial replacement of ZnO4 units of ZS nanocrystals by AlO4 units due to generation of vacancies. Fourier transform infrared (FTIR) reflection spectroscopy was used to evaluate its structural evolution. Vickers hardness study indicates marked improvement of hardness in the resultant glass‐ceramics compared with its precursor glass. The photoluminescence spectra of Eu3+ ions exhibit emission transitions of 5D0→7Fj (j = 0, 1, 2, 3, and 4) and its excitation spectra show an intense absorption band at 395 nm. These spectra reveal that the luminescence performance of the glass–ceramic nanocomposites is enhanced up to 17‐fold with the process of heat treatment. This enhancement is caused by partitioning of Eu3+ ions into glassy phase instead of into the willemite crystals with progress of heat treatment. Such luminescent glass–ceramic nanocomposites are expected to find potential applications in solid‐state red lasers, phosphors, and optical display systems. 相似文献
6.
Silvana M. Demarchi Natalia A. Quintero Ruiz Analía Concellón Sergio A. Giner 《Food and Bioproducts Processing》2013,91(4):310-318
Fruit leathers are pectic gels, eaten as snack or dessert, obtained by dehydrating fruit purees. In this work, apple leathers were prepared by a hot-air drying process which allows the formation of a gel, following the “saccharide–acid–high methoxyl pectin” gelation mechanism. Leathers were produced at 50, 60 and 70 °C, from two formulations: control and added with potassium metabisulphite (KM) as antioxidant. The drying process was studied applying a diffusive model, while antioxidant capacity (AC) losses were represented by a first-order model. Activation energy for drying (20.6 kJ/mol) was lower than those estimated for AC losses in control (31.5 kJ/mol) and KM-added (37.9 kJ/mol) leathers. Therefore, the drying time reduction achieved by increasing air temperature is not sufficient to decrease AC losses in the range covered. AC retention decreased in both formulations at increasing air temperature. KM-added samples showed higher AC retention than the controls, except for those dried at 70 °C. Kinetic constants were lower for KM-added samples, suggesting a protective effect of the additive, especially at moderate air temperatures. In the most favorable situation, AC retention was of only 16%. Therefore, the functional character of these products may not be preserved if dried with hot air and the research on economically viable, less-severe drying technologies should be intensified. 相似文献
7.
Pérez AA Farías SS Strobl AM Pérez LB López CM Piñeiro A Roses O Fajardo MA 《The Science of the total environment》2007,376(1-3):51-59
Baseline concentration levels of As, B, Ca, Cd, Cr, Cu, Co, Fe, Mg, Mn, Mo, Ni, P, Pb, Se, V, and Zn were determined for Porphyra columbina and Ulva sp. collected from three locations along San Jorge Gulf, in Patagonia Argentina. Elements were quantified by inductively coupled plasma-optical emission spectrometry, with the exception of lead and cadmium in some samples which were determined by electrothermal atomic absorption spectrometry. Three stations with different exposure degree to human activities, Bahía Solano, the mouth of Arroyo La Mata stream and Punta Maqueda, were selected as sampling points. The results showed a wide range of metal retention capacity between the two studied species. Regarding the levels of pollutants found in the researched sites, Punta Maqueda seemed to be less influenced by anthropogenic activities than the other two sites except for Cd. Taking into account their toxicities seasonal variations in Pb and Cd levels were studied in both algae in Punta Maqueda. Maximum concentrations of Cd (9.8 microg g(-1) dry wt.) were observed in P. columbina during winter, and maximum levels of Pb (0.82 microg g(-1) dry wt.) were detected in Ulva sp. during summer. Legislative and health safety aspects were evaluated for Cd and Pb. 相似文献
8.
Atiar Rahaman Molla Anal Tarafder Basudeb Karmakar 《Journal of Materials Science》2011,46(9):2967-2976
Glasses were prepared by the melt-quench technique in the K2O–SiO2–Bi2O3–TiO2 (KSBT) system and crystallized bismuth titanate, BiT (Bi4Ti3O12) phase in it by controlled heat-treatment at various temperature and duration. Different physical, thermal, optical, and
third-order susceptibility (χ3) of the glasses were evaluated and correlated with their composition. Systematic increase in refractive index (n) and χ3 with increase in BiT content is attributed to the combined effects of high polarization and ionic refraction of bismuth and
titanium ions. Microstructural evaluation by FESEM shows the formation of polycrystalline spherical particles of 70–90 nm
along with nano-rods of average diameter of 85–90 nm after prolonged heat treatment. A minor increase in dielectric constants
(εr) has been observed with increase in polarizable components of BiT in the glasses, whereas a sharp increase in εr in glass–ceramics is found to be caused by the formation of non-centrosymmetric and ferroelectric BiT nanocrystals in the
glass matrix. 相似文献
9.
Starch Consolidation Casting of Cordierite Precursor Mixtures—Rheological Behavior and Green Body Properties
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María Laura Sandoval Mariano H. Talou Analía G. Tomba Martinez María Andrea Camerucci Eva Gregorová Willi Pabst 《Journal of the American Ceramic Society》2015,98(10):3014-3021
The rheology of suspensions and mechanical properties of green bodies with cordierite composition (raw materials 37 wt% kaolin, 41 wt% talc, 22 wt% alumina, resulting in 46.6 wt% SiO2, 38.1 wt% Al2O3, 13.6 wt% MgO) and two types of starch (corn or potato) are investigated. Rotational viscometry of suspensions with solids loading 50, 60, and 70 wt% without starch showed that all tend to be shear‐thinning with a small degree of thixotropy. Suspensions with a total solids loading of 60 wt% with 25 wt% replaced by starch exhibited higher viscosity and thixotropy, but the viscometric behavior is almost identical for the two starch types (apparent viscosities 130–50 mPa ·s). Oscillatory rheometry shows that for suspensions with potato starch the onset temperature for gelatinization is 61°C–63°C, that is, lower than for corn starch (72°C–73°C). Maximum storage moduli and phase shift values after gelatinization are similar for both systems. The mechanical properties of green disks, measured via diametral compression tests, reveal clear differences between materials prepared with corn and potato starch, with the latter showing higher elastic modulus, higher strength, and higher deformation at fracture, obviously because of incompletely gelatinized starch granules in the green bodies prepared with corn starch . 相似文献
10.
Analí Castellanos-Gutiérrez Tania G. Sánchez-Pimienta Alicia Carriquiry Teresa H. M. da Costa Ana Carolina Ariza 《Nutrition journal》2018,17(1):114