227 research outputs found
Asymmetry and Symmetry of real exchange rate effect on the bilateral trade balance between Vietnam and the United States: aggregated and disaggregated levels of investigation
Bilateral trade balance always deserves particular interest of policy makers and economists. In this paper, we examined the asymmetric and symmetric effect of real exchange rate on bilateral trade balance between Vietnam and the US at both aggregated and disaggregated commodity levels. We employed both Linear Autoregressive Distributed Lag (ARDL) and Non-linear ARDL (NARDL) models to a dataset spanning over 18 years. We found that (i) both symmetry and asymmetry of real exchange rates are not significant to explain the total trade balance between Vietnam and the United States; (ii) unlike the insignificant effect on the aggregated level, the empirical evidence at the disaggregated level is mixed and dependent on product category. Our findings reveal that (iii) the claim of unfair trade by using exchange rate from the US Treasury is unclear from our estimations; and (iv) a depreciation of USD (i.e. appreciation of VND) leads the long-run US’s trade balance will improve for 10 commodities, and whereas an appreciation of USD (depreciation of VND), long-run trade balance will improve for 11 commodities. The results suggest that only a number of specific industries will benefit from USD appreciation or depreciation
Asymmetry and Symmetry of real exchange rate effect on the bilateral trade balance between Vietnam and the United States: aggregated and disaggregated levels of investigation
Bilateral trade balance always deserves particular interest of policy makers and economists. In this paper, we examined the asymmetric and symmetric effect of real exchange rate on bilateral trade balance between Vietnam and the US at both aggregated and disaggregated commodity levels. We employed both Linear Autoregressive Distributed Lag (ARDL) and Non-linear ARDL (NARDL) models to a dataset spanning over 18 years. We found that (i) both symmetry and asymmetry of real exchange rates are not significant to explain the total trade balance between Vietnam and the United States; (ii) unlike the insignificant effect on the aggregated level, the empirical evidence at the disaggregated level is mixed and dependent on product category. Our findings reveal that (iii) the claim of unfair trade by using exchange rate from the US Treasury is unclear from our estimations; and (iv) a depreciation of USD (i.e. appreciation of VND) leads the long-run US’s trade balance will improve for 10 commodities, and whereas an appreciation of USD (depreciation of VND), long-run trade balance will improve for 11 commodities. The results suggest that only a number of specific industries will benefit from USD appreciation or depreciation
Effects of foundation mass on dynamic responses of beams subjected to moving oscillators
This paper aims at the effects of foundation mass on the dynamic responses of beams subjected to moving oscillators. To achieve this aim, experiments were performed for a beam resting on the foundation considering effects of the foundation model including linear elastic spring, shear layer, viscous damping. In addition, special effects of mass density of foundation during vibration were established to obtain the characteristic parameter of the influence of foundation mass based on natural circular frequency of the structure system determined from FFT plots of the time history of acceleration data. Furthermore, the experimental parameters were used to analyze the influence of the foundation mass on the dynamic response of the beam subjected to moving oscillator. Comparisons between experimental and simulated results showed that the foundation mass showed significant effects on the dynamic characteristic response of the beam system. It increased the general vibrating mass of the structure system. Hence, it decreased of the natural frequency of the structural system and caused a significant increase on the dynamic response of the beam when compared with the case without considering the foundation mass. Finally, the relationships between the foundation properties and the parameters of foundation mass were derived and discussed
The influence of foundation mass on dynamic response of track-vehicle interaction
The influence of foundation mass on the dynamic response of track-vehicle interaction is studied in this paper. The moving vehicle is modeled as a two-axle mass-spring-damper four-degrees-of-freedom system. A new dynamic foundation model, called "Dynamic foundation model" including linear elastic spring, shear layer, viscous damping and foundation mass parameter, is used to analyze the dynamic response of the track-vehicle interaction. The railway track on the new dynamic foundation model subjected to a moving vehicle is regarded as an integrated system. By means of the finite element method and dynamic balance principle, the governing equation of motion for railway track-vehicle-foundation interaction is derived and solved by the step-by-step integration method. The accuracy of the algorithm is verified by comparing the numerical results with the other numerical results in the literature. The influence of foundation mass parameter on the dynamic response of railway track-vehicle interaction is investigated. The numerical results show that with the new dynamic foundation model the foundation mass effects more significantly on the dynamic response of track-vehicle interaction. The study shows that the new dynamic foundation model describes the true behavior of soil in the analysis of dynamic response of structures on the foundation
KINETIC STUDY OF SYNTHESIS REACTION OF LIGNOSULFONATE USING ISOTHERMAL DIFFERENTIAL SCANNING CALORIMETRY METHOD
The kinetics of lignin methylsulfonation were studied in solution by using differential scanning calorimetry (DSC) techniques under an isothermal program, at 55, 65, 75 and 85°C, respectively. It was found that activation energy, Eα =  41.26 kJ/mol, and preexponential factor A was 1.85×103 s-1
Transformer-Based Deep Learning Detector for Dual-Mode Index Modulation 3D-OFDM
In this paper, we propose a deep learning-based signal detector called
TransD3D-IM, which employs the Transformer framework for signal detection in
the Dual-mode index modulation-aided three-dimensional (3D) orthogonal
frequency division multiplexing (DM-IM-3D-OFDM) system. In this system, the
data bits are conveyed using dual-mode 3D constellation symbols and active
subcarrier indices. As a result, this method exhibits significantly higher
transmission reliability than current IM-based models with traditional maximum
likelihood (ML) detection. Nevertheless, the ML detector suffers from high
computational complexity, particularly when the parameters of the system are
large. Even the complexity of the Log-Likelihood Ratio algorithm, known as a
low-complexity detector for signal detection in the DM-IM-3D-OFDM system, is
also not impressive enough. To overcome this limitation, our proposal applies a
deep neural network at the receiver, utilizing the Transformer framework for
signal detection of DM-IM-3D-OFDM system in Rayleigh fading channel. Simulation
results demonstrate that our detector attains to approach performance compared
to the model-based receiver. Furthermore, TransD3D-IM exhibits more robustness
than the existing deep learning-based detector while considerably reducing
runtime complexity in comparison with the benchmarks
Deep Neural Network-Based Detector for Single-Carrier Index Modulation NOMA
In this paper, a deep neural network (DNN)-based detector for an uplink
single-carrier index modulation nonorthogonal multiple access (SC-IM-NOMA)
system is proposed, where SC-IM-NOMA allows users to use the same set of
subcarriers for transmitting their data modulated by the sub-carrier index
modulation technique. More particularly, users of SC-IMNOMA simultaneously
transmit their SC-IM data at different power levels which are then exploited by
their receivers to perform successive interference cancellation (SIC)
multi-user detection. The existing detectors designed for SC-IM-NOMA, such as
the joint maximum-likelihood (JML) detector and the maximum likelihood
SIC-based (ML-SIC) detector, suffer from high computational complexity. To
address this issue, we propose a DNN-based detector whose structure relies on
the model-based SIC for jointly detecting both M-ary symbols and index bits of
all users after trained with sufficient simulated data. The simulation results
demonstrate that the proposed DNN-based detector attains near-optimal error
performance and significantly reduced runtime complexity in comparison with the
existing hand-crafted detectors
Vietnamese version of the general medication adherence scale (Gmas):Translation, adaptation, and validation
Background: We aimed to translate, cross-culturally adapt, and validate the General Medication Adherence Scale (GMAS) into Vietnamese. Methods: We followed the guidelines of Beaton et al. during the translation and adaptation process. In Stage I, two translators translated the GMAS to Vietnamese. Stage II involved synthesizing the two translations. Stage III featured a back translation. Stage IV included an expert committee review and the creation of the pre-final version of the GMAS, and in stage V, pilot testing was conducted on 42 Vietnamese patients with type 2 diabetes. The psychometric validation process evaluated the reliability and validity of the questionnaire. The in-ternal consistency and test–retest reliability were assessed by Cronbach’s alpha and Spearman’s correlation coefficients. The construct validity was determined by an association examination between the levels of adherence and patient characteristics. The content validity was based on the opinion and assessment score by the expert committee. The Vietnamese version of the GMAS was created, in-cluding 11 items divided into three domains. There was a good equivalence between the English and the Vietnamese versions of the GMAS in all four criteria. Results: One hundred and seventy-seven patients were participating in the psychometric validation process. Cronbach’s alpha was acceptable for all questionnaire items (0.817). Spearman’s correlation coefficient of the test–retest reliability was acceptable for the GMAS (0.879). There are significant correlations between medication adherence levels and occupation, income, and the Beliefs about Medicines Questionnaire (BMQ) score regarding construct validity. Conclusions: The Vietnamese version of GMAS can be considered a reliable and valid tool for assessing medication adherence in Vietnamese patients
Effect of loading paths on hydroforming ability of stepped hollow shaft components from double layer pipes
The step hollow shaft components are composed of two layers of different materials, they are formed using tube hydroforming process due to its high strength and rigidity, low weight and flexible profiles, compared to traditional casting, welding, and forming methods. These products are effectively used in industries such as the automotive, shipbuilding, aerospace and defense, and oil and gas sectors. The success of various double layer pipe hydroforming process depends on several factors, with the most important being the internal pressure path and axial loading path. This paper presents research on the effect of input loading paths on the hydroforming ability of a different two-layer metal structure - an outer layer of SUS304 stainless steel and an inner layer of CDA110 copper - using 3D numerical simulations on Abaqus/CAE software. Output criteria were used to evaluate the forming ability of the formed components, including Von Mises stress, Plastic strain component (PEmax), wall thinning, and pipe profile, based on which the input loading paths were combined during the forming process. These output criteria allow for more accurate predictions of material behavior during the hydroforming process, as well as deformation and stress distribution. This can support the design process, improve product quality, reduce errors, and increase production efficiency. The research results can be applied as a basis for optimizing load paths for the next experimental step in the near future, for undergraduate and graduate training, as well as allowing designers and engineers to optimize the process of hydroforming of different 2-layer tubes, reducing costs, improving accuracy, flexible design, minimizing risks, and increasing efficienc
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