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Humanoid robots have been utilized in many fields such as medical, construction, and disaster response. While humanoid robots nowadays can achieve great capabilities, the one-leg balancing task still poses a challenging problem. This paper aims to propose a novel approach to solve the problem.

To aid the balance of one leg in humanoid robot, an external balance mechanism is inserted to the back of the humanoid robot. First, a dynamic model of the humanoid robot with balance mechanism and its simplified model are introduced. Second, a backstepping-based control method is utilized to build the proposed controller for one-leg stance system through two steps. For the first step, a minimum observer-based controller with a virtual control input is used to control the first sub-system reaching the desired reference input. For the second step, a virtual control input is considered as a reference input of a second sub-system, then a model reference adaptive controller (MRAC) is employed to control the second sub-system reaching the virtual control input in presence of uncertainties. By using the external balance mechanism, the sideway balancing task is separated from normal walking function. Furthermore, the utilization of the balance mechanism ensures the humanoid robot's hip adduction does not exceed the threshold of a human when walking. Finally, a simulation study is carried out to evaluate the effectiveness of the proposed method.

This paper proposes a model reference adaptive control using state observer for balancing one leg of humanoid robot in stance phase that extends our previous research (Tran et al., 2021).

The main research contents have been introduced.

In the COVID-19 outbreak periods, people's life has been deranged, leading to disrupt the world. Firstly, the number of deaths is growing and has the potential to surpass the highest level at any time. Secondly, the pandemic broke many countries' fortified lines of epidemic prevention and gave people a more honest view of its seriousness. Finally, the pandemic has an impact on life, and the economy led to a shortage in medical, including a lack of clinicians, facilities and medical equipment. One of those, a simple ventilator is a necessary piece of medical equipment since it might be useful for a COVID-19 patient's treatment. In some cases, the COVID-19 patients require to be treated by modern ventilators to reduce lung damage. Therefore, the addition of simple ventilators is a necessity to relieve high work pressure on medical bureaucracies. Some low-income countries aim to build a simple ventilator for primary care and palliative care using locally accessible and low-cost components. One of the simple principles for producing airflow is to squeeze an artificial manual breathing unit (AMBU) iterative with grippers, which imitates the motion of human fingers. Unfortunately, the squeezing angle of grippers is not proportional to the exhaust air volume from the AMBU bag. This paper aims to model the AMBU bag by a mathematical equation that enables to implement on a simple controller to operate a bag-valve-mask (BVM) ventilator with high accuracy performance.

This paper provides a curvature function to estimate the air volume exhausting from the AMBU bag. Since the determination of the curvature function is sophisticated, the coefficients of the curvature function are approximated by a quadratic function through the experimental identification method. To obtain the high accuracy performance, a linear regression model and a least square method are employed to investigate the characteristic of the BVM ventilator's grippers angle with respect to the airflow volume produced by the AMBU bag.

This paper investigates the correlation between the exhausting airflow of the AMBU bag and the grippers angle of the BVM ventilator.

The experimental results validated that the regression model of the characteristic of the exhausting airflow of the AMBU bag with respect to the grippers' angle has been fitted with a coefficient over 98% within the range of 350–750 ml.

Generally, humanoid robots usually suffer significant impact force when walking or running in a non-predefined environment that could easily damage the actuators due to high stiffness. In recent years, the utilization of passive compliant series elastic actuators (SEA) for driving humanoid's joints has proved the capability in many aspects so far. However, despite being widely applied in the biped robot research field, the stable control problem for a humanoid powered by the SEAs, especially in the walking process, is still a challenge. This paper proposes a model reference adaptive control (MRAC) combined with the back-stepping algorithm to deal with the parameter uncertainties in a humanoid's lower limb driven by the SEA system. This is an extension of our previous research (Lanh et al., 2021).

Firstly, a dynamic model of SEA is obtained. Secondly, since there are unknown and uncertain parameters in the SEA model, a Model Reference Adaptive Controller (MRAC) is employed to guarantee the robust performance of the humanoid's lower limb. Finally, an experiment is carried out to evaluate the effectiveness of the proposed controller and the SEA mechanism.

This paper proposes an effective control algorithm that can be widely applied for the humanoid-SEA system. Besides, the effect of the coefficients in the control law is analyzed to further improve the response's quality.

Even though the simulation shows good results with stable system response, the practical experiment has not been implemented to fully evaluate the quality of the controller.

The MRAC is applied to control the humanoid's lower limb and the back-stepping process is utilized to combine with an external SEA system but still maintain stabilization. The simplified model of the lower-limb system proposed in the paper is proven to be appropriate and can be taken for further research in the future.

Facial recognition payment (FRP) has been recently introduced as a new cashless payment method in retail store context. Anchored on information systems and consumer theories, this research aims to investigate the key antecedents and outcomes of consumer attitudes toward this innovative payment method.

This research used a survey method to obtain data from 795 consumers at retail stores in China. The data were then analyzed by different statistical methods, including descriptive statistics, reliability analysis and structural equation modeling.

Results show that perceived usefulness, perceived ease of use and perceived innovativeness positively affect consumer attitudes toward FRP, while perceived risk negatively impacts such attitudes. In addition, consumer attitudes enhance store satisfaction, and hedonic shopping value plays a mediating role in this relationship.

This study encourages retailers to adopt FRP that can enhance consumer hedonic shopping value and satisfaction.

This study contributes to the literature by explaining both the antecedents and the outcomes of consumer attitudes toward FRP in retail context. The study also provides fresh insights into how such attitudes can improve consumers' shopping values and satisfaction in an emerging market.

“The world needs science, science needs women” is the message given by UNESCO in the program for the development of women in science” (UNESCO, 2017). In Vietnam, women’s participation and achievements in scientific research is considered a great and important resource for industrialization and modernization. Even so, are there gender differences in scientific achievement in the social science research institutes in Vietnam? What factors influence the scientific achievement of female social researchers? The answers will be based on data from a 2017 survey with a sample of 756 researchers, of which 77.6% were female. The survey was conducted by the Vietnam Academy of Social Sciences, a leading, ministry-level national center for the social sciences in Vietnam. This chapter analyzed the scientific achievements of researchers through their position as principal investigators of research projects and their publications, and factors that may impact this. Bivariate and multivariate analyses of factors that may affect the scientific achievement of researchers found that gender differences in academic achievement in the social sciences in Vietnam was still prevalent. Female researchers’ scientific achievements were lower than those of their male counterparts. The contribution to science of Vietnamese female researchers was limited by many different factors; the most important were the academic rank of the researchers and gender stereotype that considered housework the responsibility of women.

By anchoring on the ability-motivation-opportunity (AMO) framework, this research aims to examine the effect of tourists' green ability, motivation and opportunity to access green information on digital media platforms (green AMO) on their intention to stay at green hotels. The study also tests the moderating role of environmental concern and the mediating role of green attitude in this relationship.

An online survey was conducted on large Facebook groups and by an international tour operator in March 2022. Through convenience sampling, 600 responses were collected from local and international tourists. Partial least squares structural equation modeling was performed to validate the research model.

The results reveal that tourists' intention to stay at green hotels is positively affected by their green AMO through indirect and direct channels. Specifically, green AMO indirectly effects tourists' intention to stay at green hotels by raising their green attitude. The results also indicate that the direct effect is moderated by environmental concern.

The findings demonstrate the importance of facilitating tourists' access to environmental information on social media platforms, which enhances green attitude and intention to stay at green hotels. This study also proposes practical solutions that managers of green hotels can employ to target green-oriented customers and conduct environmental campaigns on digital platforms.

The research is the first to investigate the effects of tourists' green AMO on their intention to stay at green hotels. It is also the first to explore the roles of environmental concern and green attitude in this relationship.

The purpose of this paper is to test the effects of financial regulatory announcements on risk and return in the Vietnamese equity market.

The event study methodology is used for the return analysis, and asset pricing models are adjusted for the risk analysis. Various robustness tests are used, including the Corrado non-parametric ranking test and the Chesney et al. non-parametric conditional distribution test, as well as GARCH, TARCH, EGARCH and PARCH specifications for the risk models.

The authors find evidence for both negative and positive reactions as well as risk shifting behaviour in the form of a diamond risk structure.

This paper fills a major gap in the literature by investigating the market’s reaction to bank regulatory announcements across financial and non-financial sectors in the Vietnamese equity market.

The purpose of this paper is to concern the community festival of a Jing minority village in the China–Vietnam border area. Since it was designated as a national-level Intangible Cultural Heritage in 2006, the festival has undergone many changes. The festival has steadily expanded and evolved, assuming characteristics of globalization. How is the globalized character of the Wanwei festival manifested? What are the forces behind the elevation of this local festival onto the register of national events and how did it turn into an event organized by the township?

The paper is based on the results of the author’s research on the culture of Kinh people in Wanwei from 2000 to the present. From the anthropological approach, the author mainly uses method of participant observation and in-depth interviews. The author has observed the Wanwei communal festival from 2000 to the present, interviewing about 40 villagers in Wanwei in depth, they can be leaders, intellectuals, civil servants, officials or working people.

The paper is a case study of the new aspect of globalization of a village festival. The author argues that globalization can lead to a spread of global flows but in this process of globalization, villagers also want to define the local identity, they reinvent the tradition, rewrite history, create new nuances for the gods with many different purposes. Practicing the current Wanwei village festival is a vivid example of globalization from below and the politics of tradition.

The paper adds a theoretical dimension to current globalization research. The paper also points out the political, economic and social dynamics that govern the transformation of a village festival in particular and the village culture in general in the border areas. The paper is a testament to the dynamism and flexibility of villagers when participating in the current globalization process.

The purpose of this paper is twofold: to explain access to formal and informal credit in agriculture of Vietnam; and to compare the effectiveness between regular econometrics and machine learning techniques.

The multinomial logit (MNL) regression model and the random forest (RF) technique are employed for comparison purposes. To avoid heteroskedasticity, the robust covariance matrix is computed to estimate the sandwich estimator which in turn provides an asymptotic covariance matrix for biased estimators. Additionally, multicollinearity is tested among independent variables with variance inflation factors less than 3. Adequacy approach and sensitivity analysis are used to determine relevant levels of predictors. For models comparison, statistical evaluation metrics including Cohen’s κ, mean absolute error, root mean squared error and relative absolute error are employed.

The discrepancy between sensitivity analysis and adequacy approach revealed that MNL is more compatible for explaining determinants of credit participation. Due to insignificant differences in the evaluation metrics between models, the winner of choice is undetermined. Among other determinants, collateral, farmsize, income, procedure, literacy and all risk variables stand out to be critical factors when deciding borrowing schemes. While financially literate farmers tend to acquire loans from both sources, borrowing decisions against different risk sources depend on risk type and famers’ own desire to borrow.

Results of the MNL model are more consistent with literatures, which reinforce the role of collateral in the local credit scheme. Besides, financial literacy and farmers’ perception on different risk sources also influence how farmers’ borrowing strategies vary among sources.

The purpose of this paper is to discuss and test the direct and indirect effects of utilitarian, hedonic and social values integrated into the theory of planned behaviour (TPB) to achieve a deeper understanding of consumers’ intention to adopt mobile commerce (MC) in the context of a developing country, Vietnam.

Based on self-administered survey data of 382 Vietnamese consumers, a structural equation modelling approach with latent constructs is used to test the hypotheses.

Perceived values explain consumer attitudes, subjective norms and behavioural intentions in the MC context. In particular, they help to increase the explained variance of the intention to adopt MC by about 9.58 per cent compared with the TPB. Finally, a cross-effect on consumer attitudes from subjective norms is also found.

Future studies would benefit from investigating other variables (e.g. innovativeness or trust) and using actual behaviour (e.g. online purchases).

Business managers should pay attention to different forms of consumer values to understand how and why consumers adopt MC in a developing country.

This study fills the gap in the literature by simultaneously investigating the role of utilitarian, hedonic and social value in a TPB model in the MC context.