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Moment-rotation prediction of precast beam-to-column connections using extreme learning machine

  • Trung, Nguyen Thoi;Shahgoli, Aiyoub Fazli;Zandi, Yousef;Shariati, Mahdi;Wakil, Karzan;Safa, Maryam;Khorami, Majid
    • Structural Engineering and Mechanics
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    • v.70 no.5
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    • pp.639-647
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    • 2019
  • The performance of precast concrete structures is greatly influenced by the behaviour of beam-to-column connections. A single connection may be required to transfer several loads simultaneously so each one of those loads must be considered in the design. A good connection combines practicality and economy, which requires an understanding of several factors; including strength, serviceability, erection and economics. This research work focuses on the performance aspect of a specific type of beam-to-column connection using partly hidden corbel in precast concrete structures. In this study, the results of experimental assessment of the proposed beam-to-column connection in precast concrete frames was used. The purpose of this research is to develop and apply the Extreme Learning Machine (ELM) for moment-rotation prediction of precast beam-to-column connections. The ELM results are compared with genetic programming (GP) and artificial neural network (ANN). The reliability of the computational models was accessed based on simulation results and using several statistical indicators.

Quantitation and Radical Scavenging Activity Evaluation of Iridoids and Phenylethanoids from the Roots of Phlomis umbrosa (Turcz.) using DPPH Free Radical and DPPH-HPLC Methods, and their Cytotoxicity

  • Le, Duc Dat;Nguyen, Duc Hung;Zhao, Bing Tian;Min, Byung Sun;Song, Si Whan;Woo, Mi Hee
    • Natural Product Sciences
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    • v.25 no.2
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    • pp.122-129
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    • 2019
  • The roots of Phlomis umbrosa (Turcz.) (Phlomidis Radix) have been traditionally used to treat cold, reduce swelling and staunch bleeding. Four iridoids (1 - 3 and 5) and six phenylethanoid derivatives (4, and 6 - 10) were isolated from the roots of P. umbrosa. A simple, sensitive, and reliable analytical HPLC/PDA method was developed, validated, and applied to determine 10 marker compounds in Phlomidis Radix. Furthermore, the isolates were evaluated for cytotoxic and anti-oxidant activities as well as DPPH-HPLC method. Among them, compounds 4 and 6 - 9 displayed potent anti-oxidant capacities using DPPH assay with $IC_{50}$ values of $27.7{\pm}2.4$, $10.2{\pm}1.1$, $18.0{\pm}0.8$, $19.1{\pm}0.3$, and $19.9{\pm}0.6{\mu}M$, and compounds 6, 8, and 9 displayed significant cytotoxic activity against HL-60 with $IC_{50}$ values of $35.4{\pm}3.1$, $18.6{\pm}2.0$, and $42.9{\pm}3.0{\mu}M$, respectively.

Spillover Effects of FDI on Technology Innovation of Vietnamese Enterprises

  • HOANG, Duc Than;DO, Anh Duc;TRINH, Mai Van
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.1
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    • pp.655-663
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    • 2021
  • This paper aims to develop a conceptual framework for determinants of spillover effects of FDI on technology innovation of Vietnamese enterprises. The research proposes a logistic regression model for assessing how enterprises' ability to implement technological innovation is affected by the presence of FDI enterprises as well as other factors that show the change through the indirect influence of FDI such as the size of the enterprise, the type of enterprise, and the skill level of the labor force or its research and development activities. Five forms of technology innovation are considered: improving production process; product quality improvement; product expansion; expanding business activities into a new field of production; and changing business activities into a new field of production. General Statistics Office of Vietnam provided survey data to collect information from 3,166 enterprises in the manufacturing and processing industry in Hanoi, which were valid for analysis. The results show that all variables of enterprise type, size, R&D, and industry have a positive impact on the selection of one of the innovation forms. Several recommendations are further suggested to take advantage of the positive effects and minimizing the negative effects of FDI for technological innovation of Vietnamese enterprises.

Impacts of Perceived Security and Knowledge on Continuous Intention to Use Mobile Fintech Payment Services: An Empirical Study in Vietnam

  • NGUYEN, Dat Dinh;NGUYEN, Thanh Duc;NGUYEN, Trung Duc;NGUYEN, Ha Viet
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.8
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    • pp.287-296
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    • 2021
  • Stepping into the technological boom time, Vietnam has integrated into the trends of using Fintech applications as a new means of payment. This article evaluates the relationship between perceived security (including service security and platform security), knowledge, confirmation, perceived usefulness, satisfaction, attitude and lastly enterprise's images regarding the service and continuous intention to use Fintech services. The survey results of 352 Vietnamese customers using Fintech services, reliability test and extended post-acceptance model (EPAM) which is based on PAM and ECT models. From the survey, we further found out that perceived security (BSS) has no direct impact on continued intention to use, while perceived security (BSS) has positive impact on confirmation (CON), similarly, perceived usefulness (PU) and user's satisfaction (SES). Knowledge of the Mobile Fintech payment service (KNOW) has a positive impact on perceived security (BSS). Confirmation (CON) has a positive influence on perceived usefulness but in the meanwhile it has created a negative impact on user's satisfaction (SES). From the survey it can also tell that user's attitude (ATT) and enterprise image (IMG) both have a positive impact on continual intention to use Fintech services. From the research results, we also propose some recommendation to enhance the continual intention to use Fintech services in Vietnam.

Job Commitment in FDI Manufacturing Enterprises During the COVID-19 Pandemic: Empirical Evidence from Vietnam

  • LE, Quang Hieu;LE, Thi Thanh Thuy
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.4
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    • pp.163-172
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    • 2022
  • The purpose of the study is to determine the impact of several factors on employees' job commitment in ten FDI manufacturing businesses in Vietnam's Nghi Son Economic Zone during the COVID-19 Pandemic. The researchers used reliability tests, exploratory factor analysis, confirmatory factor analysis, and structural equation modeling to confirm the relationships between factors when analyzing the effect of variables on job commitment in FDI enterprises. Based on a poll of 481 respondents, the test findings showed that 07 parameters have positive effects on job satisfaction. Professional assurance, compensation, fringe benefits, supervisor, promotion, coworkers, and working conditions all have varying levels of impact. Job satisfaction, in particular, has a significant and positive impact on employees' commitment to their jobs. According to research findings, the COVID-19 pandemic has been and continues to be a unique burden for Vietnamese firms in general and FDI manufacturing enterprises in Nghi Son EZ in particular. As a result, businesses must have appropriate HRM strategies to incentivize employees to recover, stabilize, and develop in the new normal, ensuring employee loyalty to the company.

Factors Affecting Students' Decision to Choose Regional Public Universities: An Empirical Study from Vietnam

  • LE, Thi Thanh Thuy;TRAN, Minh Tuan;LE, Hoang Ba Huyen
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.4
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    • pp.143-152
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    • 2022
  • The purpose of this paper is to investigate the impact of several factors on students' decisions to attend a public institution in Vietnam's North Central area. The enrollment issue toward regional institutions is particularly critical in the Vietnam Ministry of Education and Training reforming the university enrollment process and the complicated scenario of the Covid-19 pandemic. A total of 500 students were surveyed for research samples. Data is synthesized, validated, cleaned, and analyzed using SPSS and AMOS software using methods including reliability, EFA, CFA, and SEM. The findings suggest that the proposed independent components (individual factors, study fees, advertisement, infrastructure and facilities, local features, and lastly, training activities) have a beneficial impact on students' decision to attend a public university in the North Central region. The study also found that the graduation exam outcome had a moderating effect on the relationship between registration and students' decisions. These imply targeted solutions for regional public universities to diversify training majors, improve training quality, capitalize on local advantages, increase interaction, and promote training programs and image to be more effective in attracting students and maintaining competition in the current enrollment environment.

Clerodendrum ervatamioides (Lamiaceae): A new record to the flora of Vietnam

  • Heyjoong KIM;Do Van HAI;Tran Duc THIEN;Tran The BACH;Bui Hong QUANG;Duong Thi HOAN;Le Ngoc HAN;Tran Duc BINH;Ritesh Kumar CHOUDHARY;Joongku LEE
    • Korean Journal of Plant Taxonomy
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    • v.52 no.4
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    • pp.255-261
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    • 2022
  • Clerodendrum ervatamioides C. Y. Wu was described in 1977 with its type locality in Yunnan, China. During our floristic investigation in the Muong Nhe Nature Reserve of Vietnam of Dien Bien province and in the Muong Te district of the Lai Chau province, we collected several specimens of Clerodendrum ervatamioides, marking the first record of its occurrence in Vietnam. In this paper, details of the morphological features, distribution, ecology, photo plates, and a table comparing the morphological features with its ally Clerodendrum garrettianum Craib are provided.

Anti-Inflammatory Effects of Hydroethanolic Extract from Ehretia asperula on Lipopolysaccharide-Stimulated RAW264.7 Macrophages

  • Bao Le;Vo Thi Kim Hong;Seung Hwan Yang
    • Journal of Microbiology and Biotechnology
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    • v.34 no.6
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    • pp.1340-1347
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    • 2024
  • Ehretia asperula is a medicinal plant of the Ehretiaceae family used to treat inflammatory disorders, but the underlying mechanisms are not fully elucidated. The anti-inflammatory potential was determined based on enzyme cyclooxygenase-2 (COX-2) inhibition, which showed that the 95% ethanol extract (95ECH) was most effective with a half-maximal inhibitory concentration (IC50) value of 34.09 ㎍/mL. The effects of 95ECH on phagocytosis, NO production, gene, and protein expression of the cyclooxygenase 2/prostaglandin E2 (COX-2/PGE2) and inducible nitric oxide synthase/ nitric oxide (iNOS/NO) pathways in lipopolysaccharide (LPS)-induced RAW264.7 cells were examined using the neutral red uptake and Griess assays, reverse-transcriptase polymerase chain reactions (RT-PCR), and enzyme-linked immunosorbent assays (ELISA). The results showed that 95ECH suppressed phagocytosis and the NO production in activated macrophage cells (p < 0.01). Conversely, 95ECH regulated the expression levels of mRNAs for cytokines tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) as well as the corresponding proteins. In addition, PGE2 production was inhibited in a dose-dependent manner by 95ECH, and the expression of iNOS and COX-2 mRNAs was decreased in activated macrophage cells, as expected. Therefore, 95ECH from E. asperula leaves contains potentially valuable compounds for use in inflammation management.