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Search Results: 1 - 10 of 7253 matches for " Tran Dang Nguyen "
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Prediction of the Local Scour at the Bridge Square Pier Using a 3D Numerical Model  [PDF]
Nguyen Viet Thanh, Dang Huu Chung, Tran Dinh Nghien
Open Journal of Applied Sciences (OJAppS) , 2014, DOI: 10.4236/ojapps.2014.42005
Abstract: In this paper, the problem on local scour around a single square pier was studied by using both the numerical and physical models. The numerical model for the study is FSUM based on a finite-difference method to solve the Reynolds averaged Navier-Stokes equations (RANS) and the equations for suspended sediment concentration and bed morphology. The computed result was verified through data measured in the experimental flume with a sand bed. In general, the typical features of local scour around the pier were successfully simulated by FSUM, such as stream flow, bow flow, down flow, horseshoe vortex. The comparison between the computation and experiment data shows a quite good fitness. Both numerical model and experiment results show that the maximum scour depth occurs at two front edges of the pier. Although the computed result shows a little bigger scour depth in comparison with the measurement in the physical model, it still confirms the reliability of numerical model in some measure.
Determining Semantically Equivalent Questions in a Vietnamese Language Based Document Retrieval System
Dang Tuan Nguyen,Trung Tran
International Journal of Computer Science Issues , 2012,
Abstract: Generally speaking, in the natural language based document retrieval systems, the ability to determine questions having the equivalent meanings is an important requirement, it allows the optimization of the processing mechanism of questions in related systems. To determine Vietnamese questions having the equivalent meanings for a Vietnamese language based document retrieval system, we have to solve the problems: what is the meaning of a question? And, how can we determine the equivalent meanings of these questions? In this research, we established the method which can allows to determine the Vietnamese questions having the equivalent meanings.
A Novel Solution to Query Assurance Verification for Dynamic Outsourced XML Databases
Viet Hung Nguyen,Tran Khanh Dang
Journal of Software , 2008, DOI: 10.4304/jsw.3.4.9-16
Abstract: Database outsourcing model is emerging as an important new trend beside the “application-as-a service” model. In this model, since a service provider is typically not fully trusted, security and privacy of outsourced data are significant issues. These problems are referred to as data confidentiality, user privacy, data privacy, and query assurance. Among them, query assurance takes a crucial role to the success of the database outsourcing model. To the best of our knowledge, however, query assurance, especially for outsourced XML databases, has not been concerned reasonably in any previous work. In this paper, we propose a novel index structure, named Nested Merkle B+-Tree, combining the advantages of B+-tree and Merkle Hash Tree to completely deal with three issues of query assurance known as correctness, completeness and freshness in dynamic outsourced XML databases. Experimental results with real-world datasets prove the efficiency of our proposed solution.
Characterization of Electrochromic Properties of Polyaniline Thin Films Electropolymerized in H2SO4 Solution  [PDF]
Dang Hai Ninh, Tran Thi Thao, Pham Duy Long, Nguyen Nang Dinh
Open Journal of Organic Polymer Materials (OJOPM) , 2016, DOI: 10.4236/ojopm.2016.61004
Abstract:

Polyaniline (PANI) onto indium-doped tin-oxide (ITO)-coated glass samples were prepared by electroopolymerization in 0.5 M H2SO4 solution. Structure and morphology characterization of the PANI films demonstrated that the films were grown onto ITO substrates in the form of polycrystalline microbelts separated by micropores. By analysing the UV-Vis absorption spectra of the PANI films, the energy bandgap was found to be approximately 2.75 eV. The PANI/ITO films exhibited a good reversible electrochromic display (ECD) performance when cycled in 0.1 M LiClO4 + pro-pylene carbonate. The response time of the ECD coloration was found to be as small as 15 s and the coloration efficiency was found to be 8.85 cm2 \"\"C-1. After 100 cycles of the ECD performance, the cyclic voltammetry curve of the working electrode maintained unchanged. This demonstrates that the electropolymerized PANI films can be served as a good candidate for ECD applications, taking advantage of their excellent properties in terms of chemical stability.

Minc's generating function and a Segal conjecture for Thom spectra. La fonction generatrice de Minc et une conjecture de Segal pour certains spectres de Thom
Dang Ho Hai Nguyen,Lionel Schwartz,Ngoc Nam Tran
Mathematics , 2009,
Abstract: One constructs minimal injective resolutions for certain unstable modules that appears to be the mod 2 cohomology of Thom spectra. The terms of the resolution are tensor products of Brown-Gitler modules and Steinberg modules introduced by S. Mitchell and S. Priddy. A combinatorial result of Andrews shows that the alternating sum of the Poincare series of the considered modules is zero. One gives homotopical applications of this result.
Magnetic Properties of FePt Nanoparticles Prepared by Sonoelectrodeposition
Nguyen Hoang Nam,Nguyen Thi Thanh Van,Nguyen Dang Phu,Tran Thi Hong,Nguyen Hoang Hai,Nguyen Hoang Luong
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/801240
Abstract: Sonoelectrodeposition is a useful technique to make metallic nanoparticles, using ultrasound during electrodeposition to remove nanoparticles as they grow on the cathode surface. This paper reports some structural and magnetic properties of FePt nanoparticles prepared by this method. The as-prepared Fe45Pt55 nanoparticles were ferromagnetic at room temperature. Upon annealing at 700°C for 1 h under H2 atmosphere, the saturation magnetization and the coercivity of the nanoparticles were improved significantly. The annealed nanoparticles showed a high coercivity of 13.5 kOe at 2 K and of 9 kOe at room temperature. Sonoelectrodeposition is a promising technique to make large quantity of FePt nanoparticles.
Influence of Chitosan Binder on the Adhesion of Silver Nanoparticles on Cotton Fabric and Evaluation of Antibacterial Activity  [PDF]
Nguyen Quoc Hien, Dang Van Phu, Nguyen Ngoc Duy, Le Anh Quoc, Nguyen T. Kim Lan, Hoang T. Dong Quy, Huynh T. Hong Van, Phan Ha Nu Diem, Tran Thai Hoa
Advances in Nanoparticles (ANP) , 2015, DOI: 10.4236/anp.2015.44011
Abstract: Colloidal silver nanoparticles (AgNPs) with particle size less than 10 nm and concentration of 2 mM/L (~200 mg/L) were synthesized by gamma Co-60 ray irradiation of Ag+/chitosan solutions with different chitosan concentration of 0.5%, 1% and 2% (w/v). Incorporation of AgNPs onto cotton fabric was carried out by padding method with 100% wet pick-up. The content of AgNPs deposited on cotton fabric and released from cotton fabric after repeated washing was determined by inductively couple plasma-atomic emission spectroscopy (ICP-AES). The results indicated that cotton/AgNPs fabric made from padding into AgNPs solution with 0.5% - 1% chitosan was the best one of AgNPs adhesion ability on cotton fabric. Results on antibacterial activity against S. aureus showed that cotton/AgNPs fabric with AgNPs content more than 100 mg/kg exhibited highly antibacterial activity (η > 98%). The mechanical property (tensile strength and elongation) of cotton/AgNPs fabrics was almost unchanged in comparison with untreated cotton fabric. Thus, the resultant cotton/AgNPs fabric with highly antibacterial activity can be potentially used as bed drapes and/or patient uniforms in hospitals, etc.
A novel over-sampling method and its application to miRNA prediction  [PDF]
Xuan Tho Dang, Osamu Hirose, Thammakorn Saethang, Vu Anh Tran, Lan Anh T. Nguyen, Tu Kien T. Le, Mamoru Kubo, Yoichi Yamada, Kenji Satou
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.62A029
Abstract:

MicroRNAs (miRNAs) are short (~22nt) non-coding RNAs that play an indispensable role in gene regulation of many biological processes. Most of current computational, comparative, and non-comparative methods commonly classify human precursor micro- RNA (pre-miRNA) hairpins from both genome pseudo hairpins and other non-coding RNAs (ncRNAs). Although there were a few approaches achieving promising results in applying class imbalance learning methods, this issue has still not solved completely and successfully yet by the existing methods because of imbalanced class distribution in the datasets. For example, SMOTE is a famous and general over-sampling method addressing this problem, however in some cases it cannot improve or sometimes reduces classification performance. Therefore, we developed a novel over-sampling method named incre-mental- SMOTE to distinguish human pre-miRNA hairpins from both genome pseudo hairpins and other ncRNAs. Experimental results on pre-miRNA datasets from Batuwita et al. showed that our method achieved better Sensitivity and G-mean than the control (no over- sampling), SMOTE, and several successsors of modified SMOTE including safe-level-SMOTE and border-line-SMOTE. In addition, we also applied the novel method to five imbalanced benchmark datasets from UCI Machine Learning Repository and achieved improvements in Sensitivity and G-mean. These results suggest that our method outperforms SMOTE and several successors of it in various biomedical classification problems including miRNA classification.

Predicting residue contacts for protein-protein interactions by integration of multiple information  [PDF]
Tu Kien T. Le, Osamu Hirose, Vu Anh Tran, Thammakorn Saethang, Lan Anh T. Nguyen, Xuan Tho Dang, Duc Luu Ngo, Mamoru Kubo, Yoichi Yamada, Kenji Satou
Journal of Biomedical Science and Engineering (JBiSE) , 2014, DOI: 10.4236/jbise.2014.71005
Abstract: Detailed knowledge of interfacial region between interacting proteins is not only helpful in annotating function for proteins, but also very important for structure-based drug design and disease treatment. However, this is one of the most difficult tasks and current methods are constrained by some factors. In this study, we developed a new method to predict residue-residue contacts of two interacting protein domains by integrating information about evolutionary couplings andamino acid pairwise contact potentials, as well as domain-domain interaction interfaces. The experimental results showed that our proposed method outperformed the previous method with the same datasets. Moreover, the method promises an improvement in the source of template-based protein docking.
Evaluation of the MODS Culture Technique for the Diagnosis of Tuberculous Meningitis
Maxine Caws, Dang Thi Minh Ha, Estee Torok, James Campbell, Do Dang Anh Thu, Tran Thi Hong Chau, Nguyen van Vinh Chau, Nguyen Tran Chinh, Jeremy Farrar
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0001173
Abstract: Background Tuberculous meningitis (TBM) is a devastating condition. The rapid instigation of appropraite chemotherapy is vital to reduce morbidity and mortality. However rapid diagnosis remains elusive; smear microscopy has extremely low sensitivity on cerebrospinal fluid (CSF) in most laboratories and PCR requires expertise with advanced infrastructure and has sensitivity of only around 60% under optimal conditions. Neither technique allows for the microbiological isolation of M. tuberculosis and subsequent drug susceptibility testing. We evaluated the recently developed microscopic observation drug susceptibility (MODS) assay format for speed and accuracy in diagnosing TBM. Methodology/Principal Findings Two hundred and thirty consecutive CSF samples collected from 156 patients clinically suspected of TBM on presentation at a tertiary referal hospital in Vietnam were enrolled into the study over a five month period and tested by Ziehl-Neelsen (ZN) smear, MODS, Mycobacterial growth Indicator tube (MGIT) and Lowenstein-Jensen (LJ) culture. Sixty-one samples were from patients already on TB therapy for >1day and 19 samples were excluded due to untraceable patient records. One hundred and fifty samples from 137 newly presenting patients remained. Forty-two percent (n = 57/137) of patients were deemed to have TBM by clinical diagnostic and microbiological criteria (excluding MODS). Sensitivity by patient against clinical gold standard for ZN smear, MODS MGIT and LJ were 52.6%, 64.9%, 70.2% and 70.2%, respectively. Specificity of all microbiological techniques was 100%. Positive and negative predictive values for MODS were 100% and 78.7%, respectively for HIV infected patients and 100% and 82.1% for HIV negative patients. The median time to positive was 6 days (interquartile range 5–7), significantly faster than MGIT at 15.5 days (interquartile range 12–24), and LJ at 24 days (interquartile range 18–35 days) (P<0.01). Conclusions We have shown MODS to be a sensitive, rapid technique for the diagnosis of TBM with high sensitivity, ease of performance and low cost (0.53 USD/sample).
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