NOVEL OPTIMAL COORDINATED VOLTAGE CONTROL FOR DISTRIBUTION NETWORKS USING DIFFERENTIAL EVOLUTION TECHNIQUE

This paper investigates a Distributed Generators (DG) connected to distribution networks offer multiple benefits for power networks and environments in the case of renewable sources. Nevertheless, if there is not an appropriate planning and control strategy, several issues, such as voltage rise problems and increased power losses, may happen. In order to overcome such disadvantages, in this paper, a coordinated voltage control method for distribution networks with multiple distributed generators is proposed. This method is based on a differential evolution DE approach to obtain the optimal setting points for each control component. Furthermore this proposed method considers both of time-varying load demand and production, leading to not only an improvement in the voltage profile but also to optimally minimize the active power loss

Concepts of Agri-Competitiveness in Theorical and Imperical Researchs

The purpose of this study is to analyze the competitiveness of exported agricultural products through theoretical and empirical studies, estimation methods and determinants. Not only summarizing the competitiveness theories of agricultural products exported from previous studies, the article also clarifies the concept of competitiveness of agricultural products at the level of products/services, firms/ farms, industry, thereby helping firms from agricultural countries - which rely heavily on agricultural production and agricultural products export to find the right ways to identify definitions and concepts, then choose the right methods of measurement, compare its export agricultural products competitiveness. Since, the study also proposed the use of synthetic indicators to measure the competitiveness of agricultural exports which is an important basis for the state agencies in the study and propose their export policy of agricultural products in the near future

Evaluating Tourism Digital Marketing Activities: Case Study of Moc Chau, Son La, Viet Nam

In the context of 4.0, Digital Marketing is becoming more and more important for all aspects of life, including tourism. This study aims to examine the tourist’s evaluation of the use of tourism digital marketing (digital marketing tools) by travel agencies in Moc Chau, Son La. The results show that “Social Media Marketing” has the maximum level of appearance, level of attraction and level of influence. In addition, “Video Marketing” and “Multimedia Marketing” also have a high frequency of appearance, level of attraction, and high level of influence. From studying the theoretical basis of Digital Marketing, with the survey results and in-depth interviews, the research team proposes to make some suggestions to improve the efficiency of using digital marketing tools for Moc Chau tourism and government agencies

Real-Space Approach for the Electronic Calculation of Twisted Bilayer Graphene Using the Orthogonal Polynomial Technique

We discuss technical issues involving the implementation of a computational method for the electronic structure of material systems of arbitrary atomic arrangement. The method is based on the analysis of time evolution of electron states in the real lattice space. The Chebyshev polynomials of the first kind are used to approximate the time evolution operator.  We demonstrate that the developed method is powerful and efficient since the computational scaling law is linear. We invoked the method to study the electronic properties of special twisted bilayer graphene whose atomic structure is quasi-crystalline. We show the density of states of an electron in this graphene system as well as the variation of the associated time auto-correlation function. We find the fluctuation of electron density on the lattice nodes forming a typical pattern closely related to the typical atomic pattern of the quasi-crystalline bilayer graphene configuration

Soft Robotic Link with Controllable Transparency for Vision-based Tactile and Proximity Sensing

Robots have been brought to work close to humans in many scenarios. For coexistence and collaboration, robots should be safe and pleasant for humans to interact with. To this end, the robots could be both physically soft with multimodal sensing/perception, so that the robots could have better awareness of the surrounding environment, as well as to respond properly to humans' action/intention. This paper introduces a novel soft robotic link, named ProTac, that possesses multiple sensing modes: tactile and proximity sensing, based on computer vision and a functional material. These modalities come from a layered structure of a soft transparent silicon skin, a polymer dispersed liquid crystal (PDLC) film, and reflective markers. Here, the PDLC film can switch actively between the opaque and the transparent state, from which the tactile sensing and proximity sensing can be obtained by using cameras solely built inside the ProTac link. In this paper, inference algorithms for tactile proximity perception are introduced. Evaluation results of two sensing modalities demonstrated that, with a simple activation strategy, ProTac link could effectively perceive useful information from both approaching and in-contact obstacles. The proposed sensing device is expected to bring in ultimate solutions for design of robots with softness, whole-body and multimodal sensing, and safety control strategies.Comment: Submitted to RoboSoft 2023 for review. Final content subjected to chang

STUDY OF NEGATIVE REFRACTIVE INDEX IN Rb FOUR-LEVEL N-TYPE ATOMIC GAS MEDIUM

In this work, we study the generation of a negative refractive index based on electromagnetically induced transparency (EIT) in a Rb four-level N-type atomic gas medium. We derive analytic expressions for the relative permittivity and relative permeability of the medium according to the parameters of the probe, pump, and signal laser fields. We then investigate the variation of the real parts of the relative permittivity and relative permeability with respect to the intensity and frequency of the pump and signal laser fields. In the presence of the pump laser beam, the medium becomes transparent to the probe laser beam even in the resonant region. At the same time, the real parts of the relative permittivity and relative permeability are simultaneously negative (i.e., the medium exhibits a negative refractive index) in the EIT spectral domain. In the presence of the signal laser beam, the EIT effect occurs over two different frequency domains of the probe beam, so a negative refractive index is also generated in these two frequency domains. The investigation of the real parts of the relative permittivity and relative permeability with intensity and frequency of the pump and signal laser fields allowed us to find the laser parameters for the appearance of the negative refractive index, which can be useful for experimental observations