Vietnam Academy of Science and Technology: Journals Online
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A TRANSFORMATION METHOD FOR ASPECT-BASED SENTIMENT ANALYSIS
Get PDFAlong with the explosion of user reviews on the Internet, sentiment analysis has becomeone of the trending research topics in the field of natural language processing. In the last five years,many shared tasks were organized to keep track of the progress of sentiment analysis for various lan-guages. In the Fifth International Workshop on Vietnamese Language and Speech Processing (VLSP2018), the Sentiment Analysis shared task was the first evaluation campaign for the Vietnamese lan-guage. In this paper, we describe our system for this shared task. We employ a supervised learningmethod based on the Support Vector Machine classifiers combined with a variety of features. Weobtained the F1-score of 61% for both domains, which was ranked highest in the shared task. For theaspect detection subtask, our method achieved 77% and 69% in F1-score for the restaurant domainand the hotel domain respectively
Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method
Get PDFSilver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods
Estimates for the elastic moduli of 2D aggregate of hexagonal-shape orthorhombic crystals with in-plane random crystalline orientations
Get PDFNumerical finite element simulations on the homogenization problem for large samples of particular 2D hexagonal-shape-geometry random orientation aggregates from the base crystals of orthorhombic symmetry have been performed. At sufficiently large random-aggregate samples, the scatter intervals of the macroscopic 2D bulk and shear elastic moduli converge toward the Voigt-Reuss-Hill bounds, and then our recently constructed theoretical estimates, which have been specified for the aggregates
THE AMOUNT AND SPECIATION OF TRACE ELEMENTS TRANSPORTED FROM RICE FIELD TO CANAL DURING A FLOODING EVENT
Get PDFTrace element pollution of soils, sediments and surface water can pose a risk for the local population and the environment of Vietnam. Rice fields can be affected by storm events, which cause the release of trace elements into surface water and transport them into drinking wells. The aim of this study was to investigate if dissolved and suspended As, Pb and Zn concentrations in surface water of a paddy rice fields and an irrigation canals increased during a flooding event and exceed the Vietnamese Surface Water Quality Standards and WHO Guidelines for Drinking-water Quality. The study site is a rice field area in the Thanh Hoa province in Central Vietnam, which experiences an average of 2.4 storms every year causing overflow of streams and low-order canals. Concentrations of As increased during the flooding event with dissolved As being the prevailing fraction, which followed a late flush behavior. Lead showed no significant difference in concentration over time. Zn concentrations only increased significantly in the canal upstream the field in the morning of the first day. Suspended Zn dominated at that time, following the first flush behavior of TSS concentrations. Concentrations of As, Pb and Zn did not exceed the Vietnamese Surface Water Quality Standards or WHO Guidelines for Drinking-water Quality at any time and they are therefore of no concern for the health of the local populatio
FUZZY COMMON SEQUENTIAL RULES MINING IN QUANTITATIVE SEQUENCE DATABASES
Get PDFCommon Sequential Rules present a relationship between unordered itemsets in which the items in antecedents have to appear before ones in consequents. The algorithms proposed to find the such rules so far are only applied for transactional sequence databases, not applied for quantitative sequence databases.The goal of this paper is to propose a new algorithm for finding the fuzzy common sequential (FCS for short) rules in quantitative sequence databases. The proposed algorithm is improved by basing on the ERMiner algorithm. It is considered to be the most effective today compared to other algorithms for finding common sequential rules in transactional sequence database. FCS rules are more general than classical fuzzy sequential rules and are useful in marketing, market analysis, medical diagnosis and treatmen
REDUCTION OF COD IN NAM SON LANDFILL LEACHATE BY ELECTRO-FENTON AS SECONDARY TREATMENT AFTER ELECTROCOAGULATION PRETREATMENT
Get PDFLandfill leachate is a high-strength wastewater that is most difficult to deal with because the fluctuating of composition and quality as well as high concentration of specific pollutants (PAH, PCBs, heavy metals) and very high ammonia nitrogen and COD concentrations. So, after a pre-treatment as electrocoagulation, over 73% of COD has been treated from Nam Son landfill leachate, however the output value of COD still exceeds the QCVN 40:2011/BTNMT, column B. So, an electro-fenton process was employed to secondarily treat Nam Son landfill leachate, after an electrocoagulation pre-treatment. This electro-fenton system used a Pt gauze anode and a commercial carbon felt cathode to electrogenerate in situ hydrogen peroxide and regenerate ferrous ion as catalyst. In this study, the effects of various operating conditions such as initial pH, concentration of Fe2+ catalyst, current applied on reduction of COD in Nam Son landfill leachate were examined. At the optimal condition: applied current of 1A, pH 3, Fe2+ concentration of 0.1m M, Na2SO4 concentration of 0.05 M, 77.2% COD reduction can be reached within 60 min and the output value of COD is 130.9 mg.L-1, according to QCVN 40:2011/BTNMT, column B. The research results indicated that electro-fenton process can promise as a potential method in practice for secondary treatment of landfill leachate
Efficiency of β-glucan utilisation in fish culture
Get PDFIn the last three decades aquaculture is a rapidly developing sector worldwide and antibiotics are used popularly as growth promoter. Antibiotic use was banned because research proved that antibiotic has caused many effects on environment and human health. Therefore, finding antibiotic alternatives is the first priority. The most prospect products today are probiotic and prebiotic. β-glucan is one of the immunostimulants which showed a variety of benefits to the health of many aquaculture species. In this paper only the results of β-glucan, a kind of prebiotic supplied in aquaculture, were summarized. The major benefit of β-glucan are to boost growth, to reduce mortality, to enhance tolerance or stress resistance to environmental or pathogen challenges. Although the applications of β-glucan are popular worldwide, its use in aquaculture in Vietnam is still limited. This paper provides an important reference for β-glucan utilisation which may help to develop a sustainable aquaculture in Vietnam
On the effective viscosity of fresh concrete: A homogenization approach
Get PDFTwo new homogenization schemes together with the classical generalized self-consistent scheme (GSC) and its extension are proposed to deal with the effective viscosity of fresh concrete. All these models exploit the composite sphere morphology of suspension made of a viscous fluid and spherical particles. They differ from each other by the ways the extra fluid zone (EFZ) located in between the composite sphere are treated. The comparison with experimental data shows that the GSC provides very good result for a well arranged particle size scale that allows mapping the whole medium by composite spheres of different size scales. However, the GSC cannot be used for a suspension with a non negligible volume of the EFZ. For such a case, extensions of the GSC those take into account the contribution of the EFZ to the overall viscous behavior of the system is necessary to fit with experimental data. Two of them work very well for non-cohesive particles and the other can be employed for suspension with cohesive particles such as the case of fresh cement paste
STUDY ON CHANGES IN CHEMICAL COMPOSITIONS AND BIOACTIVE COMPOUNDS IN POUTERIA CAMPECCHIANA FRUIT DURING STORAGE
Get PDFABSTRACT - QMFS 2019 Pouteria campecchiana, a fruit cultivated in many provinces of the Mekong Delta, is typically eaten fresh and has many benefits to human health. Therefore, quality control during storage of this fruit is very important for fresh consumption and food processing. This study was conducted to investigate the effects of postharvest maturity on the quality of the fruit stored at room temperature, mainly on its chemical composition and bioactive compounds content. The results showed that storage time greatly affected amounts of carotenoids, tannin, phenolic and flavonoids: Highest content of carotenoids, polyphenols, flavonoids were obtained at day 10th of storage while tannin content gradually declined. The greatest antioxidant activity of fruit extracts was also obtained after 10 days storage. It was recommended that highest nutritional value of Pouteria campecchiana can be achieved from 8 to 10 days after harvest