Dissemination of Ethnic Cultures of Characteristic Villages in Guangxi from the Perspective of Rural Revitalization

Currently, in the implementation stage of China’s rural revitalization strategy, the cultivation and construction of characteristic villages is of great significance. On the basis of reviewing the relevant research on characteristic villages, this study deeply analyzes the problem that ethnic cultures have not played a sufficient role in the construction of characteristic villages in Guangxi, while proposing two key points in the construction of characteristic villages in Guangxi, i.e., the activation of ethnic cultures of characteristic villages in Guangxi, and the aggregation of cultural dissemination talents, so as to collaboratively promote the construction of characteristic villages in Guangxi

Systematic study on propulsive performance of tandem hydrofoils for a wave glider

This paper presents the propulsive performance optimization of tandem hydrofoils equipped in a wave glider in head sea conditions with the aid of computational fluid dynamic (CFD) method by using a commercial CFD code, STAR-CCM+. Firstly, this work performs a systematic study on a single 2D hydrofoil to study the effect of varying the pivot position and the torsional spring stiffness to seek for the optimum propulsive performance within a range of velocity. Secondly, parametric studies on the propulsive performance of 2D and 3D six tandem hydrofoils are conducted by varying the oscillation amplitude and the torsional spring stiffness. The result reports: The results show that the torsional springs play a critical role in propulsive performance, comparing to the pivot position. The propulsive performance of the middle hydrofoil is greater than the others in the fore and after positions. When 2D and 3D six tandem hydrofoils achieve the optimum propulsive performance, the frequency ratio is chosen to be around 25 (torsional spring stiffness (k S =0.8N⋅m/rad)) and 17 (torsional spring stiffness (k S =11.8N⋅m/rad)), respectively. Comparing to previous study, the propulsive performance of each hydrofoil in six tandem hydrofoil configuration is greatly improved and none of hydrofoil produce negative thrust

Adaptive robust control for networked strict-feedback nonlinear systems with state and input quantization

Funding Information: Funding: This work was supported in part by the National Natural Science Foundation of China under Grant 62022031, Grant 61773135, Grant U20A20188; and in part by the Fundamental Research Funds for the Central Universities. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Backstepping method is a successful approach to deal with the systems in strict-feedback form. However, for networked control systems, the discontinuous virtual law caused by state quantization introduces huge challenges for its applicability. In this article, a quantized adaptive robust control approach in backsetpping framework is developed in this article for networked strict-feedback nonlinear systems with both state and input quantization. In order to prove the efficiency of the designed control scheme, a novel form of Lyapunov candidate function was constructed in the process of analyzing the stability, which is applicable for the systems with nondifferentiable virtual control law. In particular, the state and input quantizers can be in any form as long as they meet the sector-bound condition. The theoretic result shows that the tracking error is determined by the pregiven constants and quantization errors, which are also verified by the simulation results.publishersversionpublishe

Integrated Propulsion and Cabin-Cooling Management for Electric Vehicles

This paper presents two nonlinear model predictive control (MPC) methods for the integrated propulsion and cabin-cooling management of electric vehicles. An air-conditioning (AC) model, which has previously been validated on a real system, is used to accomplish system-level optimization. To investigate the optimal solution for the integrated optimal control problem (OCP), we first build an MPC, referred to as a joint MPC, in which the goal is to minimize battery energy consumption while maintaining cabin-cooling comfort. Second, we divide the integrated OCP into two small-scale problems and devise a co-optimization MPC (co-MPC), where speed planning on hilly roads and cabin-cooling management with propulsion power information are addressed successively. Our proposed MPC methods are then validated through two case studies. The results show that both the joint MPC and co-MPC can produce significant energy benefits while maintaining driving and thermal comfort. Compared to regular constant-speed cruise control that is equipped with a proportion integral (PI)-based AC controller, the benefits to the battery energy earned by the joint MPC and co-MPC range from 2.09% to 2.72%. Furthermore, compared with the joint MPC, the co-MPC method can achieve comparable performance in energy consumption and temperature regulation but with reduced computation time

Minimalist and High-Performance Semantic Segmentation with Plain Vision Transformers

In the wake of Masked Image Modeling (MIM), a diverse range of plain, non-hierarchical Vision Transformer (ViT) models have been pre-trained with extensive datasets, offering new paradigms and significant potential for semantic segmentation. Current state-of-the-art systems incorporate numerous inductive biases and employ cumbersome decoders. Building upon the original motivations of plain ViTs, which are simplicity and generality, we explore high-performance `minimalist' systems to this end. Our primary purpose is to provide simple and efficient baselines for practical semantic segmentation with plain ViTs. Specifically, we first explore the feasibility and methodology for achieving high-performance semantic segmentation using the last feature map. As a result, we introduce the PlainSeg, a model comprising only three 3$\times$3 convolutions in addition to the transformer layers (either encoder or decoder). In this process, we offer insights into two underlying principles: (i) high-resolution features are crucial to high performance in spite of employing simple up-sampling techniques and (ii) the slim transformer decoder requires a much larger learning rate than the wide transformer decoder. On this basis, we further present the PlainSeg-Hier, which allows for the utilization of hierarchical features. Extensive experiments on four popular benchmarks demonstrate the high performance and efficiency of our methods. They can also serve as powerful tools for assessing the transfer ability of base models in semantic segmentation. Code is available at \url{https://github.com/ydhongHIT/PlainSeg}

Performance evaluation of a tidal current turbine with bidirectional symmetrical foils

As one might expect, tidal currents in terms of ebb and flood tides are approximately bidirectional. A Horizontal Axial Tidal Turbine (HATT) with unidirectional foils has to be able to face the current directions in order to maximize current energy harvesting. There are two regular solutions to keep a HATT always facing the direction of the flow, which are transferred from wind turbine applications. One is to yaw the turbine around the supporting structure with a yaw mechanism. The other is to reverse the blade pitch angle through 180° with a pitch-adjusting mechanism. The above solutions are not cost-effective in marine applications due to the harsh marine environment and high cost of installation and maintenance. In order to avoid the above disadvantages, a turbine with bidirectional foils is presented in this paper. A bare turbine with bidirectional foils is characterized in that it has nearly the same energy conversion capability in both tidal current directions without using the yaw or pitch mechanism. Considering the working conditions of the bidirectional turbine in which the turbine is installed on a mono-pile, the effect of the mono-pile on the turbine’s performance is evaluated in this paper, especially when the turbine is downstream of the mono-pile. The paper was focused on the evaluation of the hydrodynamic performance of the bidirectional turbine. The hydrodynamic performance of the bare bidirectional turbine without any supporting structure was evaluated based on a steady-state computational fluid dynamics (CFD) model and model tests. Performance comparison has been made between the turbine with bidirectional foils and the turbine with NACA foils. The effect of the mono-pile on the performance of the bidirectional turbine was studied by using the steady-state and the transient CFD model. The steady-state CFD model was used to evaluate the effect of the mono-pile clearance, which is the distance between the mono-pile and the turbine on the performance of the turbine. The transient CFD model was used to determine the time-dependent characteristics of the turbine, such as time-dependent power and drag coefficients. The results show that the bare bidirectional turbine has nearly the same energy conversion capability in both tidal current directions. The performance of the bidirectional turbine is inferior to the turbine with NACA foils. At the designed tip speed ratio, the power coefficient of the turbine with NACA foils is 0.4498, which increases by 1.6% compared to the 0.4338 of the bidirectional turbine. The turbine’s performance decreases due to the introduction of the mono-pile, and the closer the turbine is to the mono-pile, the greater effect on the turbine’s performance the mono-pile has. At the designed clearance of 1.5 DS, the presence of a mono-pile decreases the peak Cp value by 1.82% and 3.17% to a value of 0.4156 and 0.4004 for the turbine located in the mono-pile upstream and downstream, respectively. The mono-pile can result in the fluctuation of the turbine’s performance. This fluctuation will detrimentally harm the life of the turbine as it will lead to increased wear and fatigue issues