Tran T.-T.,Lac Hong University
Neural Computing and Applications | Year: 2017
Accurately forecasting the demand for international and domestic tourism is a key goal for tourism industry leaders. The purpose of this study is to present more appropriate models for forecasting the demand for tourism in Vietnam. The authors apply GM(1,1), Verhulst, DGM(1,1) and DGM(2,1) to test which concise prediction models can improve the ability to predict the number of tourists visiting this country. In order to guarantee the accuracy of forecasting process, data cover in the period from 2005 through 2013 and are obtained from the official website of VNATR “Vietnam National Administration of Tourism” report. The MAPE, MSE, RMSE and MAD are four important criteria which are used to compare the various forecasting models results. Key findings indicate that the optimal value of GM(1,1), Verhulst, DGM(1,1) can enhance the forecasting results perfectly with minimum predicted errors. In the case of the tourism revenue, using the Verhulst model is evidently better than the others. For the number of international and domestic tourist prediction, the application of Verhulst and DGM(1,1) models is well done. For visitors coming from specific countries (i.e., China, Korea, Taiwan, Japan and America), DGM(2,1) is very poor for predicting in this situation, whereas remaining three models GM(1,1), Verhulst, DGM(1,1) and DGM(2,1) perform excellently. The results also pointed out that the tourism demands in Vietnam are growing rapidly; thus, the governments must be well prepared for tourism industry and enhance relative fundamental construction for tourism markets. © 2017 The Natural Computing Applications Forum
Yu J.C.-C.,National Taiwan University |
Nguyen V.-H.,Lac Hong University |
Lasek J.,Institute for Chemical Processing of Coal |
Wu J.C.S.,National Taiwan University
Applied Catalysis B: Environmental | Year: 2017
The particular role of reactive facets TiO2 on photocatalytic NOx removal was systematically explored. The photo selective catalytic reduction (photo-SCR) of NOx was studied using titania nanosheet photocatalysts. The titania nanosheets were synthesized by hydrothermal method with titanium n-butoxide (TBOT) and hydrofluoric acid (HF). The synthetic pathway of transformation from TBOT (Ti precursor) to TiO2 nanosheet was clearly revealed that TiOF2 is the intermediate during the hydrothermal process. The NO conversion of titania nanosheets was found to be higher than the conversion of commercial P25 and TiO2 synthesized by the sol-gel method. Moreover, one of the titania nanosheets, FT1.5, displayed the highest efficiency of NOx removal at 393 K, but there was a trade-off relationship between NO conversion and NO2 selectivity. Our results suggest that the optimal synthetic process for highest efficiency of TiO2 nanosheet in photocatalysis is to use TBOT and HF with the F/Ti atomic ratio = 1.5 (FT1.5) at 453 K for 24 h. In summary, the synthesized TiO2 nanosheet exhibits great potential to be applied in NOx abatement. © 2017 Elsevier B.V.
Tran L.B.,Lac Hong University |
Le T.H.,Ho Chi Minh City University of Technology
Proceedings - 2015 IEEE International Conference on Knowledge and Systems Engineering, KSE 2015 | Year: 2015
In this paper, the authors propose a personal authentication system using a combination of both face and fingerprint features. In the proposed system, face and fingerprint features are extracted by Zernike Moment (ZM), the extracted features are classified by Relevance Vector Machine (RVM), the generated matching scores are fused using sum rule. Experimental results on the FVC2004 DB4 and ORL databases show that RVM provides better accuracy compared to unit face or fingerprint recognition and existing fusion algorithms. With respect to SVM fusion, it is observed that, the accuracy of RVM and SVM are comparable, however, the time for RVM fusion is significantly reduced. © 2015 IEEE.
Nguyen L.T.L.,HCMC University of Technology |
Nguyen C.V.,Lac Hong University |
Dang G.H.,HCMC University of Technology |
Le K.K.A.,HCMC University of Technology |
Phan N.T.S.,HCMC University of Technology
Journal of Molecular Catalysis A: Chemical | Year: 2011
A highly porous metal-organic framework (IRMOF-8) was synthesized by a solvothermal method, and used as an efficient heterogeneous catalyst for the Friedel-Crafts acylation reaction. The solid catalyst was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), atomic absorption spectrophotometry (AAS), and nitrogen physisorption measurements. High conversions were achieved in the presence of a catalytic amount of the IRMOF-8 (1-5 mol%) without the need for an inert atmosphere. The solid catalyst could be facilely separated from the reaction mixture by simple centrifugation, and could be reused without a significant degradation in catalytic activity. No contribution from homogeneous catalysis of active acid species leaching into the reaction solution was detected. © 2011 Elsevier B.V. All rights reserved.
Manh H.D.,Lac Hong University
Scientometrics | Year: 2015
This paper investigates Vietnam’s scientific publications between 1996 and 2013 from Scopus database, focusing on international collaboration. The total scientific output of the country increased about 16 publications per year during 1996–2001 and quickly increased 20 % per year during 2002–2013. However, the share of international collaboration was about 77 % of the total output. Biological and agricultural science, medicine dominated the total output, but 80–90 % of these publications are from international collaboration. In contrast, mathematics is the only field that domestic output is larger than collaboration output. Japan is the largest collaborating country, followed by United States, France, South Korea and United Kingdom. Analyzing titles of publications with these collaborating countries, we found high frequency of “Vietnam” or “Vietnamese” words. This result suggested that many study subjects of these research collaborations were from Vietnam. Furthermore, corresponding authors of these research collaborations are mainly from collaborating countries, which suggested that these research collaborations mainly led by foreign authors. Although the total output was quickly increased, especially collaboration output, Vietnamese researchers should be aware about their low contribution to these collaborations. © 2015 Akadémiai Kiadó, Budapest, Hungary
Long T.B.,Lac Hong University |
Thai L.H.,Ho Chi Minh City University of Natural Sciences |
Hanh T.,Lac Hong University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012
In this paper, the authors present a multimodal biometric system using face and fingerprint features with the incorporation of Zernike Moment (ZM) and Radial Basis Function (RBF) Neural Network for personal authentication. It has been proven that face authentication is fast but not reliable while fingerprint authentication is reliable but inefficient in database retrieval. With regard to this fact, our proposed system has been developed in such a way that it can overcome the limitations of those uni-modal biometric systems and can tolerate local variations in the face or fingerprint image of an individual. The experimental results demonstrate that our proposed method can assure a higher level of forge resistance in comparison to that of the systems with single biometric traits. © 2012 Springer-Verlag.
Cu T.S.,Vietnam Academy of Science and Technology |
Cao V.D.,Lac Hong University |
Nguyen C.K.,Vietnam Academy of Science and Technology |
Tran N.Q.,Vietnam Academy of Science and Technology
Macromolecular Research | Year: 2014
In this paper, we report the preparation and stabilization of colloidal silver nanoparticle solution, with the assistance of chitosan dihydroxyphenyl acetamide (CDHPA), or oligochitosan dihydroxyphenyl acetamide (OCDHPA). The structure of the chitosan derivatives were characterized by nuclear magnetic resonance (1H NMR) spectroscopy. The morphology of the synthesized silver core-chitosan shell nanoparticles were observed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques, and showed a well-defined core-shell structure of polymer-coated silver nanoparticles (AgNPs). The core-shell NPs exhibited a strong antibacterial activity against E. coli and S. aureus, at a very low concentration of AgNPs (2.5 ppm). Our studies offer a new method for the preparation and protection of silver nanoparticles for antibacterial applications. [Figure not available: see fulltext.] © 2014 The Polymer Society of Korea and Springer Sciene+Business Media Dordrecht.
Shu M.-H.,National Kaohsiung University of Applied Sciences |
Chiu C.-C.,National Kaohsiung University of Applied Sciences |
Nguyen T.-L.,National Kaohsiung University of Applied Sciences |
Nguyen T.-L.,Lac Hong University |
Hsu B.-M.,Cheng Shiu University
Expert Systems with Applications | Year: 2014
For monitoring online manufacturing processes, the proportion of weights imposed on each type of product's defects (nonconformities or demerits) has a profoundly effective impact on control charts' performance. Apparently, the demerit-chart approach is superior than the widely-used c-chart scheme, because it allows us to place relative precise weights (real numbers) on defects according to their distinctly inferior degrees affecting the product quality so that the abnormal variations of processes can be literally exposed. However, in many applications, the seriousness of defects is evaluated partially or entirely by the inspectors' perceptive judgement or knowledge, so with the precise-weight assignment, the demerit rating mechanism is considered to be somewhat constrained and subjective which inevitably leads to the targeted manufacturing process with limited and possibly biased information for online surveillance. To cope with the drawback, a demerit-fuzzy rating system and monitoring scheme is proposed in this paper. We first incorporate fuzzy weights (fuzzy numbers) to properly reflect the severity measures of defects which are categorized linguistically. Then, based on properties of fuzzy set theory and proposed approaches for fuzzy-number ranking, we develop the demerit-fuzzy charting scheme which is capable of discriminating process conditions into multi-intermittent statuses between in-control and out-of-control. This approach improves the traditional process control techniques with the binary-classification restraint for the process conditions. Finally, the proposed demerit-fuzzy rating system, monitoring scheme, and classification is elucidated by an application in garment industry to monitor textile-stitching nonconformities conditions. © 2014 Elsevier Ltd. All rights reserved.
Wang C.-N.,National Kaohsiung University of Applied Sciences |
Nguyen N.-T.,National Kaohsiung University of Applied Sciences |
Nguyen N.-T.,Lac Hong University |
Tran T.-T.,Lac Hong University
Scientific World Journal | Year: 2015
The growth of economy and population together with the higher demand in energy has created many concerns for the Indian electricity industry whose capacity is at 211 gigawatts mostly in coal-fired plants. Due to insufficient fuel supply, India suffers from a shortage of electricity generation, leading to rolling blackouts; thus, performance evaluation and ranking the industry turn into significant issues. By this study, we expect to evaluate the rankings of these companies under control of the Ministry of Power. Also, this research would like to test if there are any significant differences between the two DEA models: Malmquist nonradial and Malmquist radial. Then, one advance model of MPI would be chosen to see these companies' performance in recent years and next few years by using forecasting results of Grey system theory. Totally, the realistic data 14 are considered to be in this evaluation after the strict selection from the whole industry. The results found that all companies have not shown many abrupt changes on their scores, and it is always not consistently good or consistently standing out, which demonstrated the high applicable usability of the integrated methods. This integrated numerical research gives a better "past-present-future" insights into performance evaluation in Indian electricity industry. © 2015 Chia-Nan Wang et al.
Le D.-H.,Ton Duc Thang University |
Nguyen K.-H.,Lac Hong University
Procedia Engineering | Year: 2016
The present study aims to investigate the fresh and hardening properties of a soil-based controlled low-strength material (CLSM) containing stainless steel slag as a cementitious material. This type of CLSM primarily uses in construction as a trench-fill material. Four levels of the cement substitution (i.e. 0%, 10%, 20%, and 30%) and three amounts of binder content (80-, 100-, and 130 kg/m3) were generated for the experimental work. Fresh and hardening properties of the recommended CLSM were examined in the laboratory. The results show that the proposed CLSM could be employed for eco- friendly trench fills. © 2016 The Authors. Published by Elsevier Ltd.