Adaptive sliding mode control for uncertain wheel mobile robot

In this paper a simple adaptive sliding mode controller is proposed for tracking control of the wheel mobile robot (WMR) systems. The WMR are complicated systems with kinematic and dynamic model so the error dynamic model is built to simplify the mathematical model. The sliding mode control then is designed for this error model with the adaptive law to compensate for the mismatched. The proposed control scheme in this work contains only one control loop so it is simple in both implementation and mathematical calculation. Moreover, the requirement of upper bounds of disturbance that is popular in the sliding mode control is cancelled, so it is convenient for real world applications. Finally, the effectiveness of the presented algorithm is verified through mathematical proof and simulations. The comparison with the existing work is also executed to evaluate the correction of the introduced adaptive sliding mode controller. Thoroughly, the settling time, the peak value, the integral square error of the proposed control scheme reduced about 50% in comparison with the compared disturbance observer based sliding mode control

Efficient Finetuning Large Language Models For Vietnamese Chatbot

Large language models (LLMs), such as GPT-4, PaLM, and LLaMa, have been shown to achieve remarkable performance across a variety of natural language tasks. Recent advancements in instruction tuning bring LLMs with ability in following user's instructions and producing human-like responses. However, the high costs associated with training and implementing LLMs pose challenges to academic research. Furthermore, the availability of pretrained LLMs and instruction-tune datasets for Vietnamese language is limited. To tackle these concerns, we leverage large-scale instruction-following datasets from open-source projects, namely Alpaca, GPT4All, and Chat-Doctor, which cover general domain and specific medical domain. To the best of our knowledge, these are the first instructional dataset for Vietnamese. Subsequently, we utilize parameter-efficient tuning through Low-Rank Adaptation (LoRA) on two open LLMs: Bloomz (Multilingual) and GPTJ-6B (Vietnamese), resulting four models: Bloomz-Chat, Bloomz-Doctor, GPTJ-Chat, GPTJ-Doctor.Finally, we assess the effectiveness of our methodology on a per-sample basis, taking into consideration the helpfulness, relevance, accuracy, level of detail in their responses. This evaluation process entails the utilization of GPT-4 as an automated scoring mechanism. Despite utilizing a low-cost setup, our method demonstrates about 20-30\% improvement over the original models in our evaluation tasks.Comment: arXiv admin note: text overlap with arXiv:2304.08177, arXiv:2303.16199 by other author

Robust Adaptive Control of 3D Overhead Crane System

In this chapter an adaptive anti-sway controller for uncertain overhead cranes is proposed. The system model including the system uncertainties and disturbances is introduced firstly. Next, the adaptive controller which can guarantee tracking the desired position of the trolley as well as the anti-sway of the load cable is established. In this chapter, the system is proven to be input-to-state stable (ISS) which is supported by Lyapunov technique. The proposed algorithm is verified by using Matlab/Simulink simulation tool. The simulation results shown that the presented controller gives the good performances (i.e., fast transient response, position tracking, and low swing angle) when there exist system parameters variation as well as input disturbances

Factors Affecting Consumers’ Impulsive Purchasing Behavior in Circle K Convenience Stores in Hanoi, Vietnam

Impulsive purchasing behavior has been observed as one of the important studies conducted by marketers and researchers, as impulse buying has become a prevalent phenomenon in every retail format. The study was conducted to assess factors affecting consumers’ impulsive purchasing behavior in Circle K convenience stores in Hanoi, Vietnam. After reviewing a group of previous studies, the authors indicated 05 factors that affected consumers' impulsive purchasing behavior including impulsiveness, instant gratification, visual appeal, promotions and money availability. The study had selected 05 experts in the field of economics to conduct the expert interview. Moreover, the research team had also handed out the questionnaire and received 310 observations. Specifically, Impulsiveness had the strongest influence on the impulsive purchasing behavior of Circle K’s consumers in Hanoi. Keywords: factors, Impulsive purchasing behavior, Circle K convenience stores DOI: 10.7176/JESD/14-8-03 Publication date: April 30th 2023

Crystal structure of two <i>N</i>'-(1-phenyl-benzyl-idene)-2-(thio-phen-3-yl)acetohydrazides.

The synthesis, spectroscopic data, crystal and mol-ecular structures of two N'-(1-phenyl-benzyl-idene)-2-(thio-phen-3-yl)acetohydrazides, namely N'-[1-(4-hy-droxy-phen-yl)benzyl-idene]-2-(thio-phen-3-yl)acetohydrazide, C13H10N2O2S, (3a), and N'-[1-(4-meth-oxy-phen-yl)benzyl-idene]-2-(thio-phen-3-yl)acetohydrazide, C14H14N2O2S, (3b), are described. Both compounds differ in the substituent at the para position of the phenyl ring: -OH for (3a) and -OCH3 for (3b). In (3a), the thio-phene ring is disordered over two orientations with occupancies of 0.762 (3) and 0.238 (3). The configuration about the C=N bond is E. The thio-phene and phenyl rings are inclined by 84.0 (3) and 87.0 (9)° for the major- and minor-occupancy disorder components in (3a), and by 85.89 (12)° in (3b). Although these dihedral angles are similar, the conformation of the linker between the two rings is different [the C-C-C-N torsion angle is -ac for (3a) and -sc for (3b), while the C6-C7-N9-N10 torsion angle is +ap for (3a) and -sp for (3b)]. A common feature in the crystal packing of (3a) and (3b) is the presence of N-H⋯O hydrogen bonds, resulting in the formation of chains of mol-ecules running along the b-axis direction in the case of (3a), or inversion dimers for (3b). The most prominent contributions to the surface contacts are those in which H atoms are involved, as confirmed by an analysis of the Hirshfeld surface

Impact assessment of a local seventeen-year initiative on cassava-based soil conservation measure on sloping land as a climate-smart agriculture practice in Van Yen District, Yen Bai Province, Vietnam

Van Yen District in Yen Bai Province represents the general terrain conditions and farming systems of the northern mountainous region of Vietnam. It has suffered land degradation due to soil erosion and nutrient depletion, which in turn led to declined crop yield, and food insecurity. The district experienced these impacts due to unsustainable upland agricultural practices. The Department of Agriculture and Rural Development realized that their previous practices would not leave anything behind for the next generations. This prompted them to launch an agricultural conservation program in 2003 to restore degraded soils, which would improve the production in the farms, and diversify incomes and the household economy of local farmers. Over the 17 years of implementation, the program has introduced six conservation measures that have been well-received and implemented by the farmers of Van Yen. This report assesses the impacts of the 17-year program using the economic, environmental, and social lenses with a focus on the cassava crop, considering the traditional cassava monocrop system (or non-adoption group) and the six conservation measures (or adoption group). The study applied a mixed-methods approach, using semi-questionnaire to collect qualitative information from 488 farmers across six communes and surveys to collect soil samples to assess the levels of soil restoration among certain measures. The study also used the quantitative research findings from two other research studies conducted in Mau Dong Commune to help discuss its findings

Inequalities between peri-urban and urban areas in urbanization process of Ho Chi Minh city: an urban political-ecology perspective

Thanks to the implementation of Vietnam’s economic renovation or ‘Doi Moi’ policy since 1986, Ho Chi Minh City (HCMC) urban has grown quickly. However, this also leads to an increase in inequality. Its peri-urban area, which undergoes higher level of urbanization than urban area, faces more problems such as land use change, inadequate development process, unequal allocation of services and investment, and ignorance of environmental protection and cultural preservation. These impacts show inequality in standards of living between residents of the two areas. Using the framework of the Peri-Urban Political-Ecology, this paper aims to depict a general picture of the situation and analyse the causes of social inequalities between these two areas in terms of economy, public services, and environment through “everyday practices” (i.e. events, problems, stories, etc.). The paper uses HCMC’s statistical data in 2015-2017 periods and research findings from previous studies. The results shows that the main causes in inequalities between these two areas are the inevitability of urban metabolism and the unequal power interaction among the state, society and market