Support Vector Machine for Regression of Ultimate Strength of Trusses: A Comparative Study

Thanks to the rapid development of computer science, direct analyses have been increasingly used in the design of structures in lieu of member-based design methods using the effective length factor. In a direct analysis, the ultimate strength of a whole structure can be sufficiently estimated, so that the need for member capacity checks is eliminated. However, in complicated structural design problems where many structural analyses are required, the use of direct analyses requires an excessive computation cost. In such cases, Machine Learning (ML) algorithms are used to build metamodels that can predict the structural responses without performing costly structural analysis. In this paper, the support vector machine (SVM) algorithm is employed for the first time to develop a metamodel for predicting the ultimate strength of trusses using direct analysis. Several kernel functions for the SVM model, including linear, sigmoid, polynomial, radial basis function (RBF), are considered. A planar 39-bar nonlinear inelastic steel truss is taken to study the performance of the kernel functions. The results confirm the applicability of the SVM-based metamodel for predicting the ultimate strength of trusses. In particular, the RBF appears to be the best kernel among others. This investigation also provides a deeper understanding of the effect of the parameters on the efficiency of the kernel functions

Experimental Analysis on the Ultrasound-based Mixing Technique Applied to Ultra-low Sulphur Diesel and Bio-oils

Pollution in the maritime field is considered as such a serious problem that scientists, policymakers, and managers are always urged with a desire to find solutions and strategies one way or another to minimize its negative impacts on the environment and the life. Among the effective solutions, the use of fuels with limited-sulfur content or bio-based fuels has been paid much attention to due to their advantages in the use of marine diesel engines. In the current study, a type of fossil diesel fuel with ultra-low sulfur content (ULSD) was mixed with coconut oil (CO) through the ultrasonic treatment under the changes in volume fraction of as-used fuels, the correlation on viscosity selected the rate mixing between ULSD and coconut oil. After 12 minutes of ultrasound treatment, the highest stability of the ULSD-CO emulsion was achieved correspondingly to 97.8% for a mixing rate of 76%(ULSD):24%(CO) along with the distance of 85mm from the containing-vessel bottom to the ultrasound horn tip. Moreover, the spray characteristics including penetration length and a cone angle of ULSD, CO, and ULSD-CO emulsion were also examined and compared to diesel fuel. The similarity of spray characteristics to diesel fuel, containing ultra-low sulfur content and oxygen content, renewability are considered as some advantages of ULSD-CO emulsion as used for diesel engines aiming to meet the stricter requirements of IMO regulations about the strategies of environmental protection. 

Analyzing the Sea Weather Effects to the Ship Maneuvering in Vietnam’s Sea from BinhThuan Province to Ca Mau Province Based on Fuzzy Control Method

Vietnam is located in the tropical monsoon climate, so there are many storms affecting the marine environment each year. However, Vietnam’s sea also has distinct characteristics due to the continental shelf factors, salinity, sea currents and viscosity water. In this paper, the sea weather effects to the ship in the sea area from BinhThuan province to Ca Mau province are analyzed. Specifically, wave, wind and current which are the three main factors affecting the safety of ship are thoroughly examined. Importantly, the survey parameters have been built from the actual operating environment. In addition, maintaining the stability of dynamic positioning system in Vietnam weather conditions is the main point of this study

Determinants of perceived organizational support: An empirical study of administrative staff at public hospitals in viet nam

This study aimed to determine the factors that affected perceived organizational support (POS) and was conducted on participants from the administrative staff at public hospitals in Viet Nam. A quantitative approach was used for collecting and analyzing data, and hypothesis testing was performed by structural equation modeling using Smart PLS 3.0. Analysis of 128 participants showed that the perception of employees toward their organization was influenced by organizational reward, procedural justice, and perceived supervisor support. The results suggested that to increase POS, public hospitals should focus on improving their reward systems—for example, building non-financial policies that currently lack opportunities for administrative staff, such as training and promotion. The organization’s accountability policy needs to emphasize attention to transparency, and managers should listen carefully to the feedback from their employees. Finally, supervisors must nurture the goals and values of their employees. This study also provides suggestions for future research related to POS, including an expanded sample size or a cross-lagged longitudinal survey design to reduce bias. © 2021, Mahidol University - ASEAN Institute for Health Development. All rights reserved

Country uncertainty, power distance, and payment methods in acquisitions

This study examines the impact of country-specific uncertainty on the choice of payment method in international acquisitions. Our results show a negative correlation between the level of target country-specific uncertainty and cash transactions. Specifically, when the host country experiences a high level of country uncertainty, acquirers are more likely to choose non-cash transactions in which acquiring firms can issue their own equity to the target firm as part or all of the purchase consideration of the deal. The result is robust to alternative tests and analysis of subsamples. We also find that differences in uncertainty between host and home countries are informative in bidders’ payment decisions. Further, we find that the negative relation between target country-specific uncertainty and cash payment becomes weaker when there are larger differences in power distance between host and home countries. Our findings provide recommendations for policy-making bodies, and have implications for firm managers making corporate restructuring decisions

A Review of Occupational Stress among Certain Jobs in Vietnam

Background: Stress in the modern workplace is globally considered a risk factor for workers’ health and safety. However, a review of the prevalence and associated factors of occupational stress in developing countries like Vietnam was largely lacking. This review aimed to describe the situation of occupational stress among certain jobs from studies carried out in Vietnam. Methods: The review was implemented by using key words to search on online and offline, international and national database. After going through 2 stages of selections, total 25 eligible articles were chosen and used for this review. Results: The results showed the prevalence of occupational stress was varied and ranged from 6.4% to 90.4%. The study population focused on health workers, factory workers, students, academic staff and officers. The prevalence of each occupation ranged from 6.4% to 90.4% in health workers; 20.7% to 89.6% in factory workers; and 22.8% to 68.3% in students. Conclusions: In conclusion, the prevalence of occupational stress was very varied between and within each occupation. Therefore, a new way to develop in enhancing the occupational stress data, particularly in developing countries, is urgently needed

Dataset of Vietnamese students’ intention in respect of study abroad before and during COVID-19 pandemic

The Covid-19 Pandemic had completely disrupted the worldwide educational system. Many schools chose the online delivery mode for students in case learning losses incurred during social distance decree. However, as to these students who are currently in the study abroad planning stages, reached an intention crossroads, whether standing for certain unchanging decisions in study abroad destinations or changing swiftly due to the unexpected policies in quarantine. This case opened to interpretation, which was based on our e-survey since 3 May to 13 May 2020 with 397 responses covering a range of Vietnamese students. In this dataset, we focused on (i) Students’ Demographics; (ii) The previous intention of students to study abroad before and during the Covid-19 ravaged and (iii) Their intention afterwards

On the Effects of Monetary Policy in Vietnam: Evidence from a Trilemma Analysis

During and after the 2008-2009 global financial crisis, the growth cycle of Vietnam’s economy has shifted from an average annual growth rate of 7%-8% to an average annual growth rate of 5%-6% with a high level of macroeconomic instability and uncertainty from 2009 till 2016. Related studies have speculated that the operations of monetary policies during this period were not effective in recovering the economic growth and stabilizing the overall price level and total output level. This paper provides the first empirical examination of this speculation using the Trilemma framework. Our empirical results show that the State Bank of Vietnam has had adopted a set of policies aiming at maintaining exchange rate stability and interest rate independence while easing the restrictions on capital inflows. The combination of these three monetary policy approaches is found to violate the rule of Trilemma. Consequently, exchange rate and interest rate policies became less effective and failed to stabilize the economy in response to the global economic recession