Thành Phố Hà Giang, Vietnam
Thành Phố Hà Giang, Vietnam

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Nguyen T.P.,Vietnam Academy of Science and Technology | Minh N.P.,Vietnam Academy of Science and Technology | Dat T.B.,Vietnam Academy of Science and Technology | Le T.D.,Vietnam Academy of Science and Technology | And 3 more authors.
Natural Product Research | Year: 2017

For first time, the chemical constituents of the rhizomes of Luvunga scandens (Roxb.) Buch. Ham. were investigated and led to the isolation of one new limonoid named Luvunga A (1), together with seven known compounds, including one limonoid (2) and six coumarins (3–8) were isolated for the first time from the species L. scandens by various chromatography methods. Their chemical structures were elucidated by IR, UV, HR-ESI-MS, NMR 1D and 2D experiments and compared with literatures. © 2017 Informa UK Limited, trading as Taylor & Francis Group


Nguyen H.,Tien Giang University | Yang W.,Nanjing Southeast University | Sun C.,Nanjing Southeast University
Proceedings - 3rd IAPR Asian Conference on Pattern Recognition, ACPR 2015 | Year: 2015

In this paper, based on Low-rank Representation (LRR) we present a new method, Transposed Discriminative Low-Rank Representation (TDLRR), for face recognition in which both training and testing images are corrupted. By adding a discriminative term into LRR function, we obtained a low-rank matrix recovery with the increase the discriminative ability between different classes. LRR of transposed data is also applied to extract the salient features of these recovered data so as to produce effective features for classification. In addition, the test samples are also corrected by using a low-rank projection matrix between the recovery results and the original training samples. Experimental results on three popular face databases demonstrate the effectiveness and robustness of our method. © 2015 IEEE.


Nguyen H.,Nanjing Southeast University | Nguyen H.,Tien Giang University | Yang W.,Nanjing Southeast University | Yang W.,Nanjing University of Science and Technology | And 2 more authors.
Neurocomputing | Year: 2015

Face recognition is one of the fundamental problems of computer vision and pattern recognition. Based on the recent success of Low-Rank Representation (LRR), we propose a novel image classification method for robust face recognition, named Low-Rank Representation-based Classification (LRRC). Based on seeking the lowest-rank representation of a set of test samples with respect to a set of training samples, the algorithm has the natural discrimination to perform classification. We also propose a Kernel Low-Rank Representation-based Classification (KLRRC), which is a nonlinear extension of LRRC. KLRRC is firstly utilized to face recognition. By using the kernel tricks, we implicitly map the input data into the kernel feature space associated with a kernel function. We construct a transformation matrix to reduce the dimensionality of the kernel feature space, where LRRC is performed. Experimental results on several face data sets demonstrate the effectiveness and robustness of our methods. © 2015 Elsevier B.V.


Nguyen H.,Nanjing Southeast University | Nguyen H.,Tien Giang University | Yang W.,Nanjing Southeast University | Sheng B.,Nanjing Southeast University | Sun C.,Nanjing Southeast University
Neurocomputing | Year: 2016

Based on Low-Rank Representation (LRR), this paper presents a novel dictionary learning method to learn a discriminative dictionary which is more suitable for face recognition. Specifically, in order to make the dictionary more discriminating, we introduce an ideal regularization term with label information of training data to obtain low-rank coefficients. In the dictionary learning process, by optimizing the within-class reconstruction error and minimizing of between-class sub dictionaries, the learned dictionary has good representation ability for the training samples. In addition, we also suggest each sub dictionary is low-rank, which can violate with noise contained in training samples and make the dictionary more pure and compact. The learned dictionary and structured discriminative low-rank representation then will be used for classification. The proposed Discriminative Low-Rank Dictionary Learning (DLR_DL) method is evaluated on public face databases in comparison with previous dictionary learning under the same learning conditions. The experimental results demonstrate the effectiveness and robustness of our approach. © 2015 ElsevierB.V.


Tran Thi Minh T.,Okayama University | Tran Thi Minh T.,Tien Giang University | Nguyen Huu V.,Hue University | Nishino N.,Okayama University
Grassland Science | Year: 2014

To evaluate the fermentation characteristics and aerobic stability of total mixed ration (TMR) silage produced in the tropics, rice straw (Rs) and corn stover (Cst) were mixed with molasses (M) and other feeds as TMRs, which were then preserved as silage in Hue, Vietnam. The silages were opened after 4 months, and the microbial counts, fermentation product levels and aerobic stability were determined. The bacterial community was assessed by denaturing gradient gel electrophoresis (DGGE). All the silages were well preserved, with lactic acid serving as the major preservative. However, the lactic acid content was low (5.99 g kg-1 dry matter [DM]) in the Rs-M silage, while the ethanol content was substantial (37.2 g kg-1DM) in the Cst-M silage. Heating due to spoilage was observed at 115 and 81 h after silo opening in the Cst-M and Cst-TMR silages, respectively, whereas no heating was observed for 7 days after the opening of the Rs-M and Rs-TMR silages. Among the 14 bacterial strains identified in the silages by the DGGE analysis, only three were lactic acid bacteria. Lactobacillus brevis and Weissella paramesenteroides were detected in all silages, while W. cibaria was only detected in the Rs-M and Cst-M silages. In the aerobically unstable Cst-TMR silage, bands indicative of Acetobacter pasteurianus, Staphylococcus sp. and Streptomyces sp. were specifically observed. These results indicate that although desirable lactic acid fermentation can be expected in a TMR silage in a tropical environment, aerobic stability is lowered if Cst instead of Rs is used as the ingredient crop. The presence of A. pasteurianus in the air-tight laboratory silo was unusual, but it could account for the low aerobic stability of the Cst-TMR silage. © 2014 Japanese Society of Grassland Science.


Dinh N.,International University | Goberna M.A.,University of Alicante | Lopez M.A.,University of Alicante | Lopez M.A.,University of Vic | Mo T.H.,Tien Giang University
SIAM Journal on Optimization | Year: 2014

This paper provides new versions of the Farkas lemma characterizing those inequalities of the form f(x) ≥ 0 which are consequences of a composite convex inequality (S ° g)(x) ≤ 0 on a closed convex subset of a given locally convex topological vector space X, where f is a proper lower semicontinuous convex function defined on X, S is an extended sublinear function, and g is a vector-valued S-convex function. In parallel, associated versions of a stable Farkas lemma, considering arbitrary linear perturbations of f, are also given. These new versions of the Farkas lemma, and their corresponding stable forms, are established under the weakest constraint qualification conditions (the so-called closedness conditions), and they are actually equivalent to each other, as well as quivalent to an extended version of the so-called Hahn-Banach-Lagrange theorem, and its stable version, correspondingly. It is shown that any of them implies analytic and algebraic versions of the Hahn-Banach theorem and the Mazur-Orlicz theorem for extended sublinear functions. © 2014 Society for Industrial and Applied Mathematics.


Tam L.T.,Hanoi University of Science and Technology | Phan V.N.,Hanoi University of Science and Technology | Lan H.,Hanoi University of Science and Technology | Thuy N.T.,National Institute of Hygiene and Epidemiology NIHE | And 8 more authors.
Applied Physics A: Materials Science and Processing | Year: 2013

Recently, there has been an increasing need of efficient synthetic protocols using eco-friendly conditions including low costs and green chemicals for production of metal nanoparticles. In this work, silver nanoparticles (silver NPs) with average particle size about 10 nm were synthesized by using a thermal decomposition technique. Unlike the colloidal chemistry method, the thermal decomposition method developed has advantages such as the high crystallinity, single-reaction synthesis, and easy dispersion ability of the synthesized NPs in organic solvents. In a modified synthesis process, we used sodium oleate as a capping agent to modify the surface of silver NPs because the oleate has a C18 tail with a double bond in the middle, therefore, forming a kink which is to be effective for aggregative stability. Importantly, the as-synthesized silver NPs have demonstrated strong antimicrobial effects against various bacteria and fungi strains. Electron microscopic studies reveal physical insights into the interaction and bactericidal mechanism between the prepared silver NPs and tested bacteria in question. The observed excellent antibacterial and antifungal activity of the silver NPs make them ideal for disinfection and biomedicine applications. © 2013 Springer-Verlag Berlin Heidelberg.


Cao T.H.,Ho Chi Minh City University of Technology | Noi N.V.,Tien Giang University
International Journal of Intelligent Systems | Year: 2010

Lawry's label semantics for modeling and computing with linguistic information in natural language provides a clear interpretation of linguistic expressions and thus a transparent model for real-world applications. Meanwhile, annotated logic programs (ALPs) and its fuzzy extension AFLPs have been developed as an extension of classical logic programs offering a powerful computational framework for handling uncertain and imprecise data within logic programs. This paper proposes annotated linguistic logic programs (ALLPs) that embed Lawry's label semantics into the ALP/AFLP syntax, providing a linguistic logic programming formalism for development of automated reasoning systems involving soft data as vague and imprecise concepts occurring frequently in natural language. The syntax of ALLPs is introduced, and their declarative semantics is studied. The ALLP SLD-style proof procedure is then defined and proved to be sound and complete with respect to the declarative semantics of ALLPs. © 2010 Wiley Periodicals, Inc.


Le M.T.,Tien Giang University | Lee J.,Kangwon National University
Geosystem Engineering | Year: 2013

Homogeneous ZnS-Co-doped nanoparticles (ZnS:Co) were accomplished through wet chemical method with the aid of a buffer solution at room temperature. Based on theoretical calculations, the pH of the reaction and the type of buffer solution were determined. The results of X-ray diffraction analysis showed that the change of lattice constant in ZnS:Co can be detected with a change of Co concentration. The average size of ZnS nanocrystallites, estimated by the Debye-Sherrer formula, was about 3 nm. Also, optical and magnetic properties were tested with the ZnS:Co nanoparticles in various Co concentrations. © 2013 Taylor & Francis.


Thi H.N.,Hoa Sen University | Vu K.N.T.,Tien Giang University
International Conference on Ubiquitous and Future Networks, ICUFN | Year: 2016

Location-based service is one of the vital services in the Internet of Things (IoT) which merge many kinds of technologies, like Zigbee, Internet, Infrared, Bluetooth, 3G, GPRS (General Packet Radio Service), Wi-Fi, etc... Along with rapidly growing IoT, applications from personal electronics to industrial machines and sensors are getting wirelessly connected to the Internet. One of the problems is that these devices usually come with many different hardware solutions. In the art of wireless indoor positioning, a lot of research works have been done, however almost these have not addressed to this presence of hardware heterogeneity yet. This paper proposes a new positioning algorithm which is independent of hardware configurations without offline stage. By using mathematical formulation analysis, we demonstrate its advantages than the other techniques. © 2016 IEEE.

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