AUTOMATIC IDENTIFICATION OF VIETNAMESE DIALECTS

The dialect identification was studied for many languages over the world nevertheless the research on signal processing for Vietnamese dialects is still limited and there were not many published works. There are many different dialects for Vietnamese. The influence of dialectal features on speech recognition systems is important. If the information about dialects is known during speech recognition process, the performance of recognition systems will be better because the corpus of these systems is normally organized according to different dialects. This paper will present the combination of MFCC coefficients and fundamental frequency features of Vietnamese for dialectal identification based on GMM. The experiment result for the dialect corpus of Vietnamese shows that the performance of dialectal identification is increased from 59% for the case using only MFCC coefficients to 71% for the case using MFCC coefficients and the information of fundamental frequency

Pulsed Electron Deposition (PED) - a Novel Tool for Growth of Thin Films

Pulsed Electron Deposition (PED) is a novel technique that can be applied for growing high quality thin films. In this technique, we used an electron beam with a focused diameter of about 1 mm, the energy up to 15 kV, the frequency of 1-10 Hz, the pulse width of 100 ns and the total current of 1.5 kA generated in a discharge system. A remarkable advantage of this technique is the low deviation in composition from bulk to film. By using the PED technique the transparent coducting ZnO and Cu(InGa)Se$_{2 }$ films were prepared. The effect of some deposition conditions on the properties of film has been examined and discussed. For Cu(InGa)Se$_{2 }$, the best film was obtained at the discharge voltage of 12 kV and substrate temperature of 400$^\circ$C, while for ZnO, the best film was grown at the oxygen pressure of 1.3 Pa and at 400(^\circ\)C

Observations on multiple mating flights of Apis dorsata queens

This observation is aimed at providing information for a reasonable comparative study on reproductive biology among the honeybee species. The research was carried out in 1996 in the submerged Melaleuca forest of southern Vietnam, where low-nesting colonies on man-made supports, rafters, allowed us to make detailed observations on the queens. Flights of six newly emerged queens were observed and after their final mating flights, queens were dissected to count the sperm number. The five investigated queens took their first flights 6 ± 1 (mean ± SD) days after emergence. Four queens took orientation flights of less than 3 min. One queen flew to mate without any orientation flight. Mating flights happened around sunset and lasted 15.4 ± 4.3 (n = 14) min. A queen undertook two to four mating flights and after fully mating, she had 5.5 ± 0.9 (n = 5) million sperm in her spermatheca. This study indicated the extreme polyandry in A. dorsata. © Inra/DIB/AGIB/Elsevier, Pari

Development of a robotic system for automatic organic chemistry synthesis

Automated chemical synthesis carries great promises of safety, efficiency and reproducibility for both research and industry laboratories. Current approaches are based on specifically-designed automation systems, which present two major drawbacks: (i) existing apparatus must be modified to be integrated into the automation systems; (ii) such systems are not flexible and would require substantial re-design to handle new reactions or procedures. In this paper, we propose a system based on a robot arm which, by mimicking the motions of human chemists, is able to perform complex chemical reactions without any modifications to the existing setup used by humans. The system is capable of precise liquid handling, mixing, filtering, and is flexible: new skills and procedures could be added with minimum effort. We show that the robot is able to perform a Michael reaction, reaching a yield of 34%, which is comparable to that obtained by a junior chemist (undergraduate student in Chemistry)

Isolation and identification of phenolic compounds from the leaf extract of Cassia alata L.

Cassia alata is one of the most important species of the genus Cassia which is rich in anthraquinones and polyphenols. This plant is used as a medicinal material of which the leaves are known to have laxative and antibiotic properties. In our study, the methanol leaf extract of C. alata showed a significant antibacterial activity against human pathogenic bacteria strains Staphylococcus aureus and Bacillus cereus. The organic layers such as n-hexane, ethyl acetate, and aqueous layers, were prepared by partitioning the methanol extract with n-hexane and ethyl acetate successively.  We successfully isolated and identified the structures of five compounds from C. alata leaves. Their structures were elucidated by MS and NMR spectroscopic methods as well as comparison with literature data. These compounds were determined to be methyl 2,4,6-trihydroxybenzoate (1), kaempferol (2), (-)epiafzelechin (3), kaempferol-3-O-glucoside (4) and kaempferol-3-O-gentiobioside (5). Keywords. Cassia alata L., epiafzelechin, kaempferol, kaempferol-3-O-glucoside, kaempferol-3-O-gentiobioside

Experiment-based Comparative Analysis of Nonlinear Speed Control Methods for Induction Motors

Field-oriented control (FOC) for induction motors is widely used in industrial applications. By using a fast and accurate torque controller based on a stator current controller it is possible to flexibly implement advanced speed control methods to achieve proper performance both in transient and steady-state states. In this study, a deadbeat controller was used for the current loop. The nonlinear methods used for the outer loop controller were backstepping, flatness-based control, and exact feedback linearization with state derivative. The dynamic responses of these three controls were compared through various experimental results. The advantages and disadvantages of the different control structures were analyzed and evaluated in detail. Based on this evaluation, an appropriate scheme can be specified when deployed in practice