Motor Intention Decoding from the Upper Limb by Graph Convolutional Network Based on Functional Connectivity

Decoding brain intention from noninvasively measured neural signals has recently been a hot topic in brain-computer interface (BCI). The motor commands about the movements of fine parts can increase the degrees of freedom under control and be applied to external equipment without stimulus. In the decoding process, the classifier is one of the key factors, and the graph information of the EEG was ignored by most researchers. In this paper, a graph convolutional network (GCN) based on functional connectivity was proposed to decode the motor intention of four fine parts movements (shoulder, elbow, wrist, hand). First, event-related desynchronization was analyzed to reveal the differences between the four classes. Second, functional connectivity was constructed by using synchronization likelihood (SL), phase-locking value (PLV), H index (H), mutual information (MI), and weighted phase-lag index (WPLI) to acquire the electrode pairs with a difference. Subsequently, a GCN and convolutional neural networks (CNN) were performed based on functional topological structures and time points, respectively. The results demonstrated that the proposed method achieved a decoding accuracy of up to 92.81% in the four-class task. Besides, the combination of GCN and functional connectivity can promote the development of BCI.

Origami Paper-Based Electrochemical (Bio)Sensors: State of the Art and Perspective

In the last 10 years, paper-based electrochemical biosensors have gathered attention from the scientific community for their unique advantages and sustainability vision. The use of papers in the design the electrochemical biosensors confers to these analytical tools several interesting features such as the management of the solution flow without external equipment, the fabrication of reagent-free devices exploiting the porosity of the paper to store the reagents, and the unprecedented capability to detect the target analyte in gas phase without any sampling system. Furthermore, cost-effective fabrication using printing technologies, including wax and screen-printing, combined with the use of this eco-friendly substrate and the possibility of reducing waste management after measuring by the incineration of the sensor, designate these type of sensors as eco-designed analytical tools. Additionally, the foldability feature of the paper has been recently exploited to design and fabricate 3D multifarious biosensors, which are able to detect different target analytes by using enzymes, antibodies, DNA, molecularly imprinted polymers, and cells as biocomponents. Interestingly, the 3D structure has recently boosted the self-powered paper-based biosensors, opening new frontiers in origami devices. This review aims to give an overview of the current state origami paper-based biosensors, pointing out how the foldability of the paper allows for the development of sensitive, selective, and easy-to-use smart and sustainable analytical devices.

Acoustic Imaging Using the Built-In Sensors of a Smartphone

Thanks to the rapid development of the semiconductor industry, smartphones have become an indispensable part of our lives with their increasing computational power, 5G connection, multiple integrated sensors, etc. The boundary of the functionalities of a smartphone is beyond our imagination again and again as the new smartphone is introduced. In this work, we introduce an acoustic imaging algorithm by only using the built-in sensors of a smartphone without any external equipment. First, the speaker of the smartphone is used to emit sound waves with a specific frequency band. During the movement of the smartphone, the accelerometer collects acceleration data to reconstruct the trajectories of the movements, while the microphones receive the reflected waves. A microphone plus an accelerometer are able to partially replace the functionality of a microphone array and to become a symmetry-imitation system. After scanning, a series of algorithms are implemented to generate a heat map, which outlines the target object. Our algorithm demonstrates the feasibility of smartphone-based acoustic imaging with minimal equipment complexity and no additional cost, which is beneficial to the promotion and popularization of acoustic imaging technology in daily applications.

Renewal and upgrading of a courtyard building in the historic and cultural district of Beijing: Design concept of ‘multiple coexistence’ and a case study

Historic buildings in urban areas are valuable heritage and would require effective design for renovation to upgrade these buildings while preserving their heritage characteristics. This current study evaluated renovation requirements: loss of natural and spatial characteristics, single function and lack of building facade design, of a courtyard building in a Beijing historical district. Limitations of the ‘multiple coexistence’ design concept were analysed to fully achieve integration of historical, cultural, social, educational, commercial and economic values while preserving their natural characteristics. Intelligent control strategy and equipment can reshape the spatial lay out and natural environment, to enhance the building function and social value. The design strategy of the skylight to be installed in the courtyard was evaluated by simulation in this study. CFD simulation results show that the air temperature in the courtyard can increase 20% by incorporating a skylight that can be automatically closed in winter. During the summer, the skylight would be open to largely reduce the average air temperature by 1.2°C. The visual impact of external equipment can be mitigated by adding decoration to the courtyard facade. The findings should inform future development of a new design concept, to provide design paradigms for the renewal and renovation of similar historic buildings.

On-chip environmentally assisted cracking in thin freestanding SiO2 films

An on-chip fracture mechanics method is extended to characterize subcritical crack growth in submicron freestanding films. The method relies on a self-actuated concept based on MEMS fabrication principles. The configuration consists of a notched specimen attached to actuator beams involving high internal stress. Upon release, a crack initiates at the notch, propagates, and arrests. Several improvements are worked out to limit the mode III component and to avoid crack kinking. The method is applied to subcritical crack growth in 140-nm-thick SiO2 films under different humidity conditions. The data reduction scheme relates crack growth rate to stress intensity factor. The static fracture toughness value is ~ 0.73 MPa $$\sqrt{\mathrm{m}}$$ m , with standard error of 0.01 MPa $$\sqrt{\mathrm{m}}$$ m and standard deviation of 0.17 MPa $$\sqrt{\mathrm{m}}.$$ m . Subcritical crack growth rates are much smaller than in bulk specimens. A major advantage is that many test samples can be simultaneously monitored while avoiding any external equipment. Graphic Abstract

So Many Places to Love, but It’s Our Birthplace that Loves Us Back Like No Other Place

The picture depicts the beauty of Punjab, aka Land of Five Rivers, which is the northern state of India. The day when I clicked this picture, I was casually walking in our rice fields when I suddenly saw such a beautiful scene which tempted me to capture it as soon as possible. I randomly took only one shot. The ratio of sky and land is perfect and the sun enlightens this image by acting as a cherry on a cake. Technical details: I used my Samsung Galaxy M40 (mobile), without using any external equipment.

A novel flexible two-step method for eye-to-hand calibration for robot assembly system

In the visual robot system, the calibration of the hand-eye system is very important, which has a great influence on the positioning accuracy of the robot. Traditional methods are either complicated or require advanced external equipment. This paper proposes a new flexible method for hand-eye calibration, which is simple and flexible. Firstly, the robot carries the target to perform two transformation motions to solve the rotation relationship, and then the robot tool coordinate system performs several rotation motions to solve the transformation relationship. The paper provides empirical insights about how the robot hand-eye system is calibrated by controlling the robot to perform the specified motion without expensive and complicated 3D measurement equipment. The experiment and analysis indicate that the developed hand-eye calibration has high precision in 6-DOF industrial robot assembly application.

THE CARRIER SYSTEMS OF THE TRUCK FROM THE FRONT HITCH EXTERNAL EQUIPMENT

The article presents an analysis of tests of serial and experimental upper louver sieves. The adjustments of the serial and experimental sieves were the same. Comparative tests were carried out on the harvesting of wheat of the "Bezostaya-1" variety with the reference combine "don-1500" when replacing the upper sieve. The results of tests of serial and experimental louver sieves are presented.

In-Field Calibration of Triaxial Accelerometer Based on Beetle Swarm Antenna Search Algorithm

Traditional calibration method is usually performed with expensive equipments such as three-axis turntable in a laboratory environment. However in practice, in order to ensure the accuracy and stability of the inertial navigation system (INS), it is usually necessary to recalibrate the inertial measurement unit (IMU) without external equipment in the field. In this paper, a new in-field recalibration method for triaxial accelerometer based on beetle swarm antenna search (BSAS) algorithm is proposed. Firstly, as a new intelligent optimization algorithm, BSAS algorithm and its improvements based on basic beetle antennae search (BAS) algorithm are introduced in detail. Secondly, the nonlinear mathematical model of triaxial accelerometer is established for higher calibration accuracy, and then 24 optimal measurement positions are designed by theoretical analysis. In addition, the calibration procedures are improved according to the characteristics of BSAS algorithm, then 15 calibration parameters in the nonlinear method are optimized by BSAS algorithm. Besides, the results of BSAS algorithm and basic BAS algorithm are compared by simulation, which shows the priority of BSAS algorithm in calibration field. Finally, two experiments demonstrate that the proposed method can achieve high precision in-field calibration without any external equipment, and meet the accuracy requirements of the INS.