scholarly journals 3D EXTENTION OF THE VOR ALGORITHM TO DETERMINE AND OPTIMIZE THE COVERAGE OF GEOSENSOR NETWORKS

Author(s):  
S. Doodman ◽  
A. Afghantoloee ◽  
M. A. Mostafavi ◽  
F. Karimipour

Recent advances in electrical, mechanical and communication systems have led to development of efficient low-cost and multi-function geosensor networks. The efficiency of a geosensor network is significantly based on network coverage, which is the result of network deployment. Several optimization methods have been proposed to enhance the deployment efficiency and hence increase the coverage, but most of them considered the problem in the 2D environment models, which is usually far from the real situation. This paper extends a Voronoi-based deployment algorithm to 3D environment, which takes the 3D features into account. The proposed approach is applied on two case studies whose results are evaluated and discussed.

2021 ◽  
Vol 262 ◽  
pp. 03017
Author(s):  
Hadis Rakhaev ◽  
Anzor Gyatov ◽  
Zalina Ivanova ◽  
Elvira Kokova ◽  
Akhmat Chochaev

Communication and logistics are one of the most important features of the markets; they permeate and constitute its content. Communication and logistics for commodity producers are also as important attribute as production itself, and sometimes even more. For this reason, commodity producers themselves directly and explicitly, but more often through other institutions (including the government), tend to set up stable exclusive communication systems and logistics. This article analyzes the state of the prospects for the formation of communications and logistics networks for agricultural products. The correlation of existing communications and logistics of agricultural products and other types of products (including finished industrial products of various purposes: from machinery, equipment, chemical products to defense, hydrocarbon, carbon and other raw materials, timber and other goods) is analyzed. The established linkages are revealed. They were quantified, calibrated and classified. The existing principles (comparative and absolute advantages) are reviewed and new principles are formulated (marginal player, marginal linkages), which describe the real situation in the markets of agricultural products more correctly. New criteria for grouping and reformatting existing communication and logistics networks, which make it possible to increase the competitiveness of domestic agricultural products are proposed.


Author(s):  
Amando Rivas-Rodriguez

The need for prosthesis development dates back many years, but only in the last few years has material, control and automation technology been available to obtain prostheses that imitate the function and performance of the real part that is replaced. The development of prosthesis, involves the need to merge knowledge of human physiology and biomechanics, machining of materials. Currently there are various types of prostheses that are adapted to the needs of people who require them. Recent advances in bionics have made possible the development of more efficient prostheses, but at a high cost. There are limitations and challenges to be overcome in order to be successful, in addition to being accessible, for people with low resources, who only want to be able to walk and be independent, for which purpose it is intended to design and manufacture a prosthesis that supports walking to a person, with a low cost and that the people of low resources can acquire i.


2009 ◽  
Vol E92-C (7) ◽  
pp. 922-928 ◽  
Author(s):  
Kikuo MAKITA ◽  
Kazuhiro SHIBA ◽  
Takeshi NAKATA ◽  
Emiko MIZUKI ◽  
Sawaki WATANABE

Author(s):  
Dr. Jianfei Yang

COVID-19 has made a bad influence on economic and society including cultural and tourism industry in China,2020.The industry has received a huge loss in the first quarter of the year and the situation is getting worse in the near future. It is believed that there will be a long impact for the country even the world. In order to recover the industry, Chinese government has published series of policies to support the enterprises and clusters to reduce the bad influence of COVID-19. This paper mainly uses filed survey and documentary research to map the real situation of the industry. It tries to find the policy demand of the industries and then analyze the policies published by government to conquer COVID-19. Meanwhile it will focus on whether the supply meet the demand and give suggestions on how to promote the policy efficiency in the post period of COVID-19 in China. Keywords: Evaluation; Cultural Industries; Policy; Park; Pandemic


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1439
Author(s):  
Janghyuk Youn ◽  
Woong Son ◽  
Bang Chul Jung

Recently, reconfigurable intelligent surfaces (RISs) have received much interest from both academia and industry due to their flexibility and cost-effectiveness in adjusting the phase and amplitude of wireless signals with low-cost passive reflecting elements. In particular, many RIS-aided techniques have been proposed to improve both data rate and energy efficiency for 6G wireless communication systems. In this paper, we propose a novel RIS-based channel randomization (RCR) technique for improving physical-layer security (PLS) for a time-division duplex (TDD) downlink cellular wire-tap network which consists of a single base station (BS) with multiple antennas, multiple legitimate pieces of user equipment (UE), multiple eavesdroppers (EVEs), and multiple RISs. We assume that only a line-of-sight (LOS) channel exists among the BS, the RISs, and the UE due to propagation characteristics of tera-hertz (THz) spectrum bands that may be used in 6G wireless communication systems. In the proposed technique, each RIS first pseudo-randomly generates multiple reflection matrices and utilizes them for both pilot signal duration (PSD) in uplink and data transmission duration (DTD) in downlink. Then, the BS estimates wireless channels of UE with reflection matrices of all RISs and selects the UE that has the best secrecy rate for each reflection matrix generated. It is shown herein that the proposed technique outperforms the conventional techniques in terms of achievable secrecy rates.


2021 ◽  
Vol 2021 (169) ◽  
pp. 65-77
Author(s):  
Jennifer Brown Urban ◽  
Miriam R. Linver ◽  
Lisa M. Chauveron ◽  
Thomas Archibald ◽  
Monica Hargraves ◽  
...  

2021 ◽  
pp. 027836492098785
Author(s):  
Julian Ibarz ◽  
Jie Tan ◽  
Chelsea Finn ◽  
Mrinal Kalakrishnan ◽  
Peter Pastor ◽  
...  

Deep reinforcement learning (RL) has emerged as a promising approach for autonomously acquiring complex behaviors from low-level sensor observations. Although a large portion of deep RL research has focused on applications in video games and simulated control, which does not connect with the constraints of learning in real environments, deep RL has also demonstrated promise in enabling physical robots to learn complex skills in the real world. At the same time, real-world robotics provides an appealing domain for evaluating such algorithms, as it connects directly to how humans learn: as an embodied agent in the real world. Learning to perceive and move in the real world presents numerous challenges, some of which are easier to address than others, and some of which are often not considered in RL research that focuses only on simulated domains. In this review article, we present a number of case studies involving robotic deep RL. Building off of these case studies, we discuss commonly perceived challenges in deep RL and how they have been addressed in these works. We also provide an overview of other outstanding challenges, many of which are unique to the real-world robotics setting and are not often the focus of mainstream RL research. Our goal is to provide a resource both for roboticists and machine learning researchers who are interested in furthering the progress of deep RL in the real world.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Basem Aqlan ◽  
Mohamed Himdi ◽  
Hamsakutty Vettikalladi ◽  
Laurent Le-Coq

AbstractA low-cost, compact, and high gain Fabry–Perot cavity (FPC) antenna which operates at 300 GHz is presented. The antenna is fabricated using laser-cutting brass technology. The proposed antenna consists of seven metallic layers; a ground layer, an integrated stepped horn element (three-layers), a coupling layer, a cavity layer, and an aperture-frequency selective surface (FSS) layer. The proposed aperture-FSS function acts as a partially reflective surface, contributing to a directive beam radiation. For verification, the proposed sub-terahertz (THz) FPC antenna prototype was developed, fabricated, and measured. The proposed antenna has a measured reflection coefficient below − 10 dB from 282 to 304 GHz with a bandwidth of 22 GHz. The maximum measured gain observed is 17.7 dBi at 289 GHz, and the gain is higher than 14.4 dBi from 285 to 310 GHz. The measured radiation pattern shows a highly directive pattern with a cross-polarization level below − 25 dB over the whole band in all cut planes, which confirms with the simulation results. The proposed antenna has a compact size, low fabrication cost, high gain, and wide operating bandwidth. The total height of the antenna is 1.24 $${\lambda }_{0}$$ λ 0 ($${\lambda }_{0}$$ λ 0 at the design frequency, 300 GHz) , with a size of 2.6 mm × 2.6 mm. The proposed sub-THz waveguide-fed FPC antenna is suitable for 6G wireless communication systems.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1804
Author(s):  
Guangmin Ren ◽  
Hongtao Han ◽  
Yixuan Wang ◽  
Sitong Liu ◽  
Jianyong Zhao ◽  
...  

Photocatalysis holds great promise as an efficient and sustainable oxidation technology for application in wastewater treatment. Rapid progress developing novel materials has propelled photocatalysis to the forefront of sustainable wastewater treatments. This review presents the latest progress on applications of photocatalytic wastewater treatment. Our focus is on strategies for improving performance. Challenges and outlooks in this promising field are also discussed. We hope this review will help researchers design low-cost and high-efficiency photocatalysts for water treatment.


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