Journal of Science and Technology

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https://oerrepository.ntt.edu.vn/handle/298300331/3

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Đang hiển thị 1 - 20 trong tổng số 33

The Relationship between Macroeconomic Factors and the Level of Non-Performing Loans (NPLs) of Commercial Banks in Vietnam
(International Journal of Scientific & Engineering Research, 2017-03) Nguyen, Huu Quang; Nguyen, Xuan Nhi
This article is to estimate the effects of macroeconomic factors on the the level of non-performing loans (NPLs) of Commercial Banks in Vietnam by using econometric model on the commercial banks for the 2004-2015 periods. It is obvious that banks have to take risk all the time and there are three major risks, including credit risk, market risk and operational risk (Perez, 2014). Credit risk is one of the most important kinds of risk in commercial banking sector. The Basel Committee on Banking Supervision defines credit risk as the potential that a commercial bank borrower, or counter party, will fail to meet its payment obligations regarding the terms agreed with the commercial bank (Perez, 2014). This study also finds that NPLs are not the problem of the commercial bank but the government must consider it carefully. It is clear that commercial banks must have a right thought about NPLs as well as analyze the reasons to give the reasonable solutions to solve the issue. In addition, this study also points out that if the commercial banks in Vietnam try to hide the bad debt, the real status of the commercial bank will be reflected unexpectedly, leading to the results will affect to the capital supply of national economics
Genetic Diversity of a Novel Oil Crop, Camellia brevistyla, Revealed by ISSR DNA Markers
(Hiệp hội Hàn Quốc, 2017-06-19) Mong-Huai Su; Te-Hua Hsu; Chun-Neng Wang; Kuan-Hung Lin
Cluster analysis revealed seven groups of populations plus one outlier (C. kissii). Five individuals from two populations in the southern region were grouped into cluster V, and six populations from both regions were grouped into cluster VII. The remaining populations from the northern region were separated into different clusters from V and VII. Results of an analysis of molecular variance indicated that the variation within populations (75%) was predominantly greater than variations among counties (18%) and among regions (7%). Overall, the gene flow (Nm = 0.509) estimated from genetic differentiation (Gst = 0.534) suggested that gene flow among regions was limited. Higher genetic diversity (H = 0.317), Shannon’s index (I = 0.477), and gene flow (Nm = 0.538) of populations were found in the northern region compared to the southern region. The DNA sequences of C. brevistyla amplified by two oil-biosynthesis genes showed 99-100% homology with those of C. oleifera. Camellia brevistyla populations are highly differentiated and can serve as a basis for the food oil industry as a germplasm resource.
Hyperpolarization-activated cyclic nucleotide-gated gene signatures and poor clinical outcome of cancer patient
(NTT Institute of Hi-Technology, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam, 2017-07-22) Phan, Nhut Nam; Huynh, Thanh Tung; Yen-Chang Lin
Meta-analysis of public microarray data from Oncomine and NextBio Research databases to discover the mRNA expression level of HCN1-4 in cancers. Survival analysis was also used to investigate the correlation between overexpression of HCN gene family with overall survival rate of cancer patients using Kaplan-Meier Plotter database and PROGgene V2 database. Results: HCN genes (HCN1-4) over-expression and under-expression in multiples types of cancers such as CNS and brain cancer, breast cancer, colorectal cancer, melanoma, and lymphoma were found. HCN1 was significantly correlated with low overall survival of breast cancer [hazard ratio (HR) =7.42, P=0.0019] and colorectal cancer (HR =1.66, P=0.0071) patients. The lower survival rates of lung cancer (HR =2.5, P= 0.0107), kidney cancer (HR =1.1, P=0.004) and gastric cancer (HR =1.33, P=0.0037) patients were significantly correlated with the expression of HCN2. HCN3 was significantly correlated to lower survival rates of breast cancer (HR =1.65, P=0.0016), and kidney cancer (HR =1.17, P=0.0049). HCN4 was highly correlated with the lower survival rates of breast cancer of gastric cancer (HR =1.25, P=0.022), lung cancer (HR =5.37,
Research Article Fucoidan and Fucoxanthin Ameliorate Cardiac Function of Aging Canine
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2017-10-15) Chih-Hung Tsai; Phan Nam; Yen-Chang Lin
In this study, fucoidan in combination with fucoxanthin were used to enhance the impaired cardiac systolic and diastolic function in aging canine model. Materials and Methods: Aging canines were fed with fucoidan (125 mg kgG1) and fucoxanthin (125 mg kgG1) for 3 months. Echo cardiography was used to compute Tei index and related parameter such as E / E`, E` / A` and isovolumetric relaxation time (IVRT), isovolumetric contraction time (IVCT) was calculated using the Doppler model. T-Test was used to compare echo parameters. Data were displayed as Mean±SD. SPSS was used for statistical analysis. Results: IVRT and IVCT were shortened with 15.78±3.71 and 24.53±6.71%, respectively after fucoidan and fucoxanthin treatment, suggested that these two phytochemical compounds have cardioprotective effects in aging canine subjects with degenerative valve disease. Conclusion: After 3 consecutive months of Fucoidan and fucoxanthin usage, the cardiac function of aging canine was improved. Fucoidan and fucoxanthin may be considered as a potential treatment or supplement to aging canine subjects with abnormality in cardiac function.
Enhanced adsorption of methylene blue onto graphene oxide-doped XFe2O4 (X 5Co, Mn, Ni) nanocomposites: kinetic, isothermal, thermodynamicand recyclability studies
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2017-10-30) Bach, Long Giang; Tran, Van Thuan; Nguyen, Duy Trinh; Pham, Van Thinh; Do, Sy Trung
Abstract The nanocomposites XFe2O4/GO with various metal sites (X = Co, Mn, and Ni) were successfully synthesized via the polymerized complex method. The XFe2O4/GO family was characterized using X-Ray diffraction analysis, scanning electron microscopy (SEM), and a vibrating sample magnetometer. We also investigated the effect of three fundamental parameters (initial concentration, dosage, and pH) on the removal of methylene blue using the response surface methodology. A high F value, very low P value (\ 0.00001), a non-signiﬁcant lack of ﬁt, and the determination coefﬁcient (R2 [ 0.95) demonstrated a strong corre- lation between experimental and predicted values of the responses. The predicted optimal conditions for maximum removal efﬁciency were easily determined to adhere to the following trend for actual test experiments: MnFe2O4/GO (60.1%) \ CoFe2O4/GO (80.3%) \ NiFe2O4/GO (87.7%).
English Sentiment Classification using Only the Sentiment Lexicons with a Johnson Coefficient in a Parallel Network Environment
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2017-12-20) Vo, Ngoc Phu; Vo, Thi Ngoc Tran
Sentiment classification is significant in everyday life, such as in political activities, commodity production and commercial activities. In this survey, we have proposed a new model for Big Data sentiment classification. We use many sentiment lexicons of our basis English Sentiment Dictionary (bESD) to classify 5,000,000 documents including 2,500,000 positive and 2,500,000 negative of our testing data set in English. We do not use any training data set in English
A Sting Algorithm and Multi-dimensional Vectors Used for English Sentiment Classification in a Distributed System
(Trường Đại học Nguyễn Tất Thành (Tạp chí khoa học công nghệ NTT), 2017-12-20) Vo, Ngoc Phu; Vo, Thi Ngoc Tran
In this research, we have proposed a new model for Big Data sentiment classification in the parallel network environment - a Cloudera system with Hadoop Map (M) and Hadoop Reduce (R). Our new model has used a Statistical Information Grid Algorithm (STING) with multi-dimensional vector and 2,000,000 English documents of our English training data set for English document-level sentiment classification. Our new model can classify sentiment of millions of English documents based on many English documents in the parallel network environment. However, we tested our new model on our testing data set (including 1,000,000 English reviews, 500,000 positive and 500,000 negative) and achieved 83.92% accuracy
On a class of constacyclic codes of length 4ps over Fpm + uFpm
(World Scientiﬁc Publishing Company DOI, 2017-12-24) Hai Q. Dinh; Bac T. Nguyen; Songsak Sriboonchitta
Present Let p be a prime such that pm ≡3 (mod 4). For any unit λ of Fpm , we determine the algebraic structures of λ-constacyclic codes of length 4ps over the ﬁnite commutative chain ring Fpm + uFpm , u2 = 0. If the unit λ ∈ Fpm is a square, each λ-constacycliccode of length 4ps is expressed as a direct sum of an -α-constacyclic code and an α constacyclic code of length 2ps. If the unit λ is not a square, then x4 −λ0 can bedecomposed into a product of two irreducible coprime quadratic polynomials which arex2 + γx + γ2 2 and x 2 −γx + γ2 2 , where λ ps 0 = λ and γ4 = −4λ0. By showing that thequotient rings ˙` R x2+γx+γ2 2 ´ps ¸ and nR˙`x2−γx+γ2 2 ´ps ¸ are local, non-chain rings, we can compute the number of codewords in each of λ-constacyclic codes. Moreover, the duals of such codes are also given.
An analytical approach in accounting for social values of ecosystem services in a Ramsar site:
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2017-12-28) Ho, Huu Loc; Nguyen, Thi Hong Diep; Vo, Thanh Tuan; Yoshihisa Shimizud
Presented a case study in exploring relevant ES and EDS within the context of a protected area using non-monetary methods with the aid of the local community. In particular, through deliberative mapping approach, the manuscript strived to locate, quantify, and assess a full range of relevant ES and EDS as perceived by local inhabitants across the landscape of U Minh Thuong National Park (UMTNP), Vietnam. Within the scope of this paper, we also delved into how socio-cultural perceptions and preferences towards these natural resources diverge among groups of respondents. Through the presented research, we strived to consolidate the baseline understanding regarding the ES proﬁle of the research area with relevant social insights, paving the way for the design and implementation of sustainable management strategies. Finally, this manuscript also sought to present a practical measure to account for social dimensions and their relevance to the general assessment of ES..
Preparation and Characterization of Advanced PtRu/Ti0.7Mo0.7O2 Catalysts for Direct Methanol Fuel Cells
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2018-01-02) Ho, Thi Van Thanh; Bach, Long Giang; Dai, Viet
Investigating the novel Ti0.7Mo0.3O2 material can just as easily be used as a conductive support for PtRu for DMFCs to prevent not only the carbon corrosion but also improved activity of catalyst due to some functional advantages of novel Ti0.7Mo0.3O2 support. The Ti0.7Mo0.3O2 nanoparticle have good crystallinity with well-defined fringes corresponding to the 3.45 Å spacing value of the {101} plane of anatase TiO2, which were good according to the XRD pattern. The BET surface area measurements showed that the Ti0.7Mo0.3O2 possessed 125 m2 g-1 Fig. 3 shows the TEM measurement of Ti0.7Mo0.3O2 nanoparticle and Pt/Ti0.7Mo0.3O2, it can be observed that spherical PtRu alloy particles with an average particle size of 2-4 nm were uniformly anchored on the surface of Ti0.7Mo0.3O2 support. More importantly, we found that there has a strong metal support interaction (SMSI) between the PtRu noble metal and the Ti0.7Mo0.3O2 support material - resulting in facile electron donation from the Ti0.7Mo0.3O2 support to PtRu metal with an ultimate drastic decrease in the d-band vacancy of Pt.
K-Medoids algorithm used for english sentiment classification in a distributed system
(Trường Đại học Nguyễn Tất Thành, 2018-01-30) Vo, Ngoc Phu; Vo, Thi Ngoc Tran
In this research, we have proposed a new model for Big Data sentiment classification in the parallel network environment – a Cloudera system with Hadoop Map (M) and Hadoop Reduce (R). Our new model has used a K-Medoids Algorithm (PAM) with multi-dimensional vector and 2,000,000 English documents of our English training data set for English document-level sentiment classification. Our new model can classify sentiment of millions of English documents based on many English documents in the parallel network environment. However, we tested our new model on our testing data set (including 1,000,000 English reviews, 500,000 positive and 500,000 negative) and achieved 85.98% accuracy.
The Comparison of Surface Modification Methods of the Heavy Metals Adsorption of Activated Carbon from Rice Husk
(Trường Đại học Nguyễn Tất Thành, 2018-02-01) Thai, Hoa Mai; Van, Thi Thanh Ho; Nguyen, Bao Pham
Present Surface modification of activated carbon (AC) could be done through different methods in order to modify their specific physical and chemical properties to facilitate metals removal from wastewater. Three methods were used to modify the rice husk AC (RHAC) including the use of (1) HNO3, (2) dithizone and (3) the combination of HNO3 with dithizone. These modification agents were increased its affinity towards the desired pollutant. The modification methods demonstrated the effective process for the metal ions adsorption capability and the removal of them from water. For Ni2+ and Cd2+ adsorption, RHAC was modified by HNO3 giving the best adsorption capacity in comparison with using dithizone or the combination of HNO3 with dithizone. That adsorption was reached 17.23 mg/g for Ni2+ and 29.61 mg/g for Cd2+. Additionally, the surface area, which was characterized by BET (Brunauer–Emmett–Teller) of RHAC, was 710.8 m2/g and DA micropore volume was 0.447 (cm3/g). Especially, the only modified RHACs had the peak of N-H functional group by using Fourier transform infrared spectrum (FTIR). Besides, the only RHAC modification by HNO3 had peak of C=O. That significantly contributed to increase the metal ions adsorption capacity of rhac
High Photocatalytic Activity of Oliver-Like BiVO4 for Rhodamine B Degradation under Visible Light Irradiation
(Trường Đại học Nguyễn Tất Thành, 2018-02-01) Nguyen, Huu Vinh; Tran, Van Thuan; Do, Sy Trung; Nguyen, Duy Trinh
Report the facial synthesis of BiVO4 crystals with different morphologies by the solvothermal and hydrothermal process. The phase structure and morphology as-synthesized samples were characterized by XRD, FE-SEM, and UV-vis DRS spectroscopy. We also investigated the photocatalytic activity of BiVO4 for the decomposition of rhodamine B (RhB) under visible light irradiation. The results showed that oliver-like BiVO4 was obtained when using the mixed solvent of ethylene glycol and water while starflower-like BiVO4 was obtained using the mixed solvent of ethylene glycol monomethyl ether and water. The hydrothermal evolution process the BiVO4 product with a rod-like morphology. Oliver-like BiVO4 with pure monoclinic scheelite phase and high specific surface area exhibits efficient photodegradation of RhB (k = 7.82x10-3 min-1).
Removal of Cu2+ from Aqueous Water by Adsorption onto the Efficient and Recyclable Durian Shell-Derived Activated Carbon
(Trường Đại học Nguyễn Tất Thành, 2018-02-01) Bach, Long Giang; Dai Viet; Nguyen, Duy Trinh; Van, Thị Thanh Ho; Tran, Van Thuan
Vestigated the use of durian shell-derived activated carbon (DSAC) for the removal of Cu2+. To determine the optimal condition for Cu2+ removal, the response surface methodology (RSM) was used to establish a second-order polynomial model with variables such as Cu2+ concentration (Ci), adsorbent dosage (dDSAC) and pH. With R2 = 0.9847 and P-value < 0.0001, the model was proved to be statistically significant. The RSM based confirmation test revealed that the removal of Cu2+ was maximum (99.6%) at optimal conditions: Ci = 61.6 mg/L, dDSAC = 5.0 g/L and pH = 5.2. Based on calculated R2, data fitness for adsorption isotherms were positioned as follows: Langmuir > Tempkin > Freundlich. In other words, monolayer adsorption was the most favorable behavior with maximum capacity of 76.92 mg/g from Langmuir model. Interestingly, DSAC was reused at least five times without a considerable decrease of Cu2+ removal efficiency. Therefore, durian shell can be used as a highly effective, reusable and promising raw material to fabricate the activated carbon.
Synthesis the New Nanostructure Ti0.7Ir0.3O2 via Low Temperature Hydrothermal Process
(Trường Đại học Nguyễn Tất Thành, 2018-02-01) Huynh, Thien Tai; Nguyen, Van At; Pham, Quoc Hau; Bach, Long Giang
In this paper, the novel nanostructure Ti0.7Ir0.3O2 was prepared for the first time via low temperature hydrothermal process. The synthesis process for the new nanostructure Ti0.7Ir0.3O2 was studied in detail in this work. The impact of hydrothermal temperature as well as the reaction time on the dominant phase formation is extensively investigated in this work. We found that the Ti0.7Ir0.3O2 nanoparticles exist in both rutile and anatase phase. We found that the Ti0.7Ir0.3O2 nanoparticles with an irregular spherical shape with particle size of approximately 20-30nm with high crystallinity. In addition, we also found that the optimal condition to synthesize the Ti0.7Ir0.3O2 NPs is obtained at 210oC and 10 hours. The result not only introduces a promising catalyst support Ti0.7Ir0.3O2 for much needed fuel cells, but it also open a new material type of Ir doped TiO2.
English sentiment classification using a Gower-2 coefficient and a genetic algorithm With a fitness-proportionate selection in a Parallel network environment
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2018-02-28) Vo, Ngoc Phu; Vo, Thi Ngoc Tran
We have already studied a data mining field and a natural language processing field for many years. There are many significant relationships between the data mining and the natural language processing. Sentiment classification Has HAd many crucial contributions to many different fields in everyday life, such as in political Activities, commodity production, and commercial Activities. A new model using a Gower-2 Coefficient (HA) and a Genetic Algorithm (GA) with a fitness function (FF) which is a Fitness-proportionate Selection (FPS) has been proposed for the sentiment classification. This can be applied to a big data.
A Reformed K-Nearest Neighbors Algorithm for Big Data Sets
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2018-03-08) Vo, Ngoc Phu; Vo, Thị Ngoc Tran
In This Research, We Propose An Improvement To K-NN To Process Big Datasets In A Shortened Execution Time. The Reformed K-Nearest Neighbors Algorithm (R-K-NN) Can Be Implemented On Large Datasets With Millions Or Even Billions Of Data Records. R-K-NN Is Tested On A Data Set With 500,000 Records. The Execution Time Of R-K-NN Is Much Shorter Than That Of K-NN. In Addition, R-K-NN Is Implemented In A Parallel Network System With Hadoop Map (M) And Hadoop Reduce (R).
On (α + uβ)-constacyclic codes of length 4ps over Fpm+ uFpm
(Trường Đại học Nguyễn Tất Thành, 2018-03-26) Q. Hai Dinh; Nguyen. T Bac; Songsak Sriboonchitta
Present for any odd prime p such that pm ≡ 3 (mod 4), the structures of all (α + uβ)- constacyclic codes of length 4ps over the ﬁnite commutative chain ring Fpm + uFpm (u2 = 0) are established in term of their generator polynomials. When the unit (α+ uβ) is a square, each (α + uβ)-constacyclic code of length 4ps is expressed as a direct sum of two constacyclic codes of length 2ps. In the main case that the unit (α + uβ) is not a square, it is shown that the ambient ring (Fpm +uFpm )[x]∗x4ps −(α+uβ) is a principal ideal ring. From that, the structure, number of codewords, duals of all such (α + uβ)-constacyclic codes are obtained. As an application, we identify all self-orthogonal, dual-containing, and the unique self-dual (α + uβ)-constacyclic codes of length 4ps over Fpm + uFpm
Approaching human vision perception to designing visual graph in data visualization
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2020-03) Tran, Phuoc Vinh; Le, Xuan Truong
This research studies the characteristics of human vision perception and the relationships between data variables of dataset to constitute cube models representing dataset as a graph on the cube. The research proposes the process designing multidimensional graph considered as structural graph on cube model to represent multivariate data. Structural graph is designed in the light of the relationships between data variables and human vision perception. After mapping structural graph onto computer screen, the graph is integrated retinal variables to improve objectively visual features and respond subjectively human perception of vision
Bảo tồn nguồn gen cây Hồng Sim (Rhodomyrtus tomentosa) tại Vườn Quốc gia Phú Quốc
(Trường Đại học Nguyễn Tất Thành (Tạp chí Khoa học công nghệ NTT), 2020-03-30) Trần, Tuấn Kiệt; Võ, Thanh Sang
Nghiên cứu bảo tồn nguồn gen Hồng Sim tại Vườn Quốc gia Phú Quốc, thống kê 28 hộ dân trồng Hồng Sim cho thấy 50% hộ canh tác với diện tích nhỏ hơn 1 ha, trong khi chỉ 4% hộ trồng trên 5 ha, kết quả khảo sát hình thái thân, lá hoa quả và hạt của Hồng Sim được ghi nhận, đặc biệt khoảng 1 ha Hồng Sim mọc tự nhiên tại Ấp Bãi Thơm - Xã Bãi Thơm đã được khoanh vùng để bảo tồn và 2000 m2, Hồng Sim với mật độ 500 cây ha được trồng bảo tồn thành công tại Ấp Xóm Mới – Xã Bãi Thơm, kết quả nghiên cứu góp phần bảo tồn gen Hồng Sim và giúp người dân có ý thức bảo vệ Hồng Sim Phú Quốc

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