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ObjectiveThis study aims to investigate the potential vestibular pathway impairment through vestibular evoked myogenic potentials (VEMPs) and to explore the pathophysiological significance of these instrument-based findings in children with recurrent vertigo.Materials and methodsThe clinical data of 21 children (mean age 4.67 ± 1.39 years) diagnosed as RVC who met the inclusion criteria of the Bárány Society and 29 healthy children (mean age 4.83 ± 1.34 years) enrolled as the control group from February 2021 to December 2021 were collected and analyzed retrospectively. All the subjects underwent both cervical VEMP (cVEMP) and ocular VEMP (oVEMP) triggered by air-conducted sound (ACS) and galvanic vestibular stimulation (GVS), respectively. The elicit rate, latency, and amplitude asymmetry ratio (AAR) of ACS-cVEMP, ACS-oVEMP, GVS-cVEMP, and GVS-oVEMP were analyzed.Results(1) The elicit rates of ACS-cVEMP and ACS-oVEMP were similar in the two groups (P > 0.05), as well as GVS-cVEMP and GVS-oVEMP (P > 0.05). (2) P1 and N1 latencies of ACS-cVEMP and GVS-cVEMP in the RVC group were longer than those in the control group (P < 0.05). (3) The N1 latency of ACS-oVEMP in the RVC group was shorter than that in the control group (P < 0.05), while there was no significant difference in the P1 latency of ACS-oVEMP (P > 0.05). The N1 and P1 latencies of GVS-oVEMP were not significantly different (P > 0.05). (4) There was no statistical difference in the AAR of ACS-cVEMP and GVS-cVEMP. Although there was an increased AAR of ACS-oVEMP in the RVC group (P < 0.05), the AAR was within the normal range. However, no statistical difference was found in the AAR of GVS-oVEMP in the two groups (P > 0.05).ConclusionThe latencies of ACS-cVEMP and GVS-cVEMP in children with recurrent vertigo were significantly prolonged compared with those in healthy children, and there was no difference in elicit rates of ACS-cVEMP and GVS-cVEMP, suggesting that there might be potential impairment in the inferior vestibular nerve and the subsequent nerve conduction pathway in RVC.

ObjectiveWe compared the characteristics of air-conducted sound cervical vestibular evoked myogenic potential (ACS-cVEMP) and bone-conducted vibration cVEMP (BCV-cVEMP) among 3-month-old infants with normal hearing and sensorineural hearing loss (SNHL), and healthy adults to explore the feasibility and optimal strategies for infant vestibular screening.Methods29 infants (58 ears) were divided into two groups according to hearing (group I: normal hearing ears; group II: SNHL ears), 20 healthy adults were defined as group III. The results of response rate, P13 and N23 latency, P13-N23 interval, amplitudes, and corrected interaural asymmetry ratio (IAR) were recorded and compared among three groups.ResultsThe response rates of ACS-cVEMP in three groups were 88.89, 62.00, 100%, respectively. The P13 and N23 latencies, and P13-N23 interval did not differ significantly between group I and II (p = 0.866, p = 0.190, p = 0.252). A significant difference was found between group I and III (p = 0.016, p < 0.001, p < 0.001). No significant difference was observed in raw or corrected amplitude between group I and II (p = 0.741, p = 0.525), while raw and corrected amplitudes in group III were significantly larger than group I (p < 0.001, p < 0.001). For BCV-cVEMP, the response rates in three groups were 100, 86.36, 100%, respectively, No significant difference existed in the P13 and N23 latency, or P13-N23 interval between group I and II (p = 0.665, p = 0.925, p = 0.806), however, P13 and N23 latencies were significantly longer in group III than group I (p < 0.001, p = 0.018), but not in P13-N23 interval (p = 0.110). There was no significant difference in raw or corrected amplitude between group I and II (p = 0.771, p = 0.155) or in raw amplitude between group I and III (p = 0.093), however, a significant difference existed in corrected amplitude between group I and III (p < 0.001).ConclusionsCompared with adults, 3-month-old infants with normal hearing presented with equivalent response rates, shorter P13 and N23 latencies, smaller corrected amplitudes, and a wider IAR range for both ACS and BCV-cVEMP. SNHL infants had equivalent response rates of BCV-cVEMP, lower response rates of ACS-cVEMP than normal hearing infants. When responses were present, characteristics of ACS and BCV-cVEMP in SNHL infants were similar with normal hearing infants. ACS combined with BCV-cVEMP are recommended to improve the accuracy of vestibular screening.

ObjectiveThe present study aimed to investigate the status of vestibular function in children with vestibular migraine of childhood (VMC) reflected by vestibular function test battery and explore the pathophysiological implication of these instrument-based findings.MethodsThe clinical data of 22 children (mean age 10.7 ± 2.9 years) with VMC who met the diagnostic criteria of the Barany Society were collected from September 2021 to March 2022. A vestibular function test battery on these children included a caloric test, video head impulse test (vHIT), cervical vestibular-evoked myogenic potential (cVEMP), and ocular vestibular-evoked myogenic potential (oVEMP); these parameters were triggered by air-conducted sound (ACS) and galvanic vestibular stimulation (GVS). The subjects were further divided into two groups: 3 months according to the disease duration from symptom onset. The functional abnormalities and their characteristics reflected by the vestibular test battery, as well as the outcomes in children with or without aura, were analyzed.Results(1) The abnormal rate of the caloric test was 15.8% and that of vHIT was 0%. The response rates of ACS-cVEMP and ACS-oVEMP were 100% and 90.5%, respectively. The response rates of GVS-cVEMP and GVS-oVEMP were 100% and 88.9%, respectively. (2) No statistical difference was observed in the abnormal rate of the caloric test (P = 0.55) and the response rate of ACS-oVEMP (P = 0.21) between the two groups, irrespective of the course duration. (3) No statistical difference was detected in the abnormal rate of the caloric test (P = 0.53) and the response rate of ACS-oVEMP (P = 1.00) in children with or without aura.ConclusionVestibular function status comprehensively reported by the vestibular test battery did not show an aggravation with the disease duration in children with VMC. Also, it was not affected by the existence of aura in children with VMC. The high abnormal rates of the caloric test and oVEMPs (ACS-oVEMP and GVS-oVEMP) suggested that the lateral semicircular canal (low-frequency function component), the utricle, and the superior vestibular conduction pathway might be involved in VMC.

Large scale digital beamforming (LS-DBFs) are widely used in satellite communications for spectrum reuse and transmission enhancement. SRAM-FPGAs are a popular option for software defined satellite platforms due to their rich computation resources and high flexibility. However, they are sensitive to soft errors, which limit their application in space. This paper discusses the application of coding based fault tolerance schemes for the protection of LS-DBFs on software defined payloads. Since multiple FPGAs are usually needed to support the whole LS-DBFs system, different decomposition schemes are compared in terms of resource efficiency and reliability when the coding based scheme is applied to protect the DBFs on a FPGA. Theoretical analysis and hardware experiments shows that resource efficiency and reliability are a pair of contradictory requirements for decomposition schemes. The protection with vertical decomposition could improve the reliability by 96% with 1.5× redundancy. And the protection with horizontal decomposition could improve the reliability by 85% with 1.2× redundancy.

In this work, a novel method to grow high-quality and large bilayer graphene (BLG) directly on various dielectric substrates was demonstrated. Large area single-crystal monolayer graphene was applied as a seeding layer to facilitate the homo-epitaxial synthesis of single crystal BLG directly on insulating substrates. The Cu nano-powders (Cu NP) with nanostructure and high surface-area were used as the remote catalysis to provide long-lasting catalytic activity during the graphene growth. The TEM results confirmed the single-crystalline nature of the BLG domains, which validates the superiority of the homo-epitaxial growth technique. The as-grown BLG show comparable quality with the CVD-grown BLG on metal surface. Field-effect transistors directly fabricated on the as-grown BLG/SiO$ _2 $/Si showed a room temperature carrier mobility as high as 2297 cm $ ^2 $ V$ ^{-1}$ s $^{-1} $.

As one of the most well-known programmer Q&A websites, Stack Overflow (i.e., SO) is serving tens of thousands of developers every day. Previous work has shown that many developers reuse the code snippets on SO when they find an answer (from SO) that functionally matches the programming problem they encounter in their development activities. To study how programmers reuse code on SO during project development, we conduct a comprehensive empirical study. First, to capture the development activities of programmers, we collect 342,148 modified code snippets in commits from 793 open-source Java projects, and these modified code can reflect the programming problems encountered during development. We also collect the code snippets from 1,355,617 posts on SO. Then, we employ CCFinder to detect the code clone between the modified code from commits and the code from SO, and further analyze the code reuse when programmer solves a programming problem during development. We count the code reuse ratios of the modified code snippets in the commits of each project in different years, the results show that the average code reuse ratio is 6.32%, and the maximum is 8.38%. The code reuse ratio in project commits has increased year by year, and the proportion of code reuse in the newly established project is higher than that of old projects. We also find that some projects reuse the code snippets from many years ago. Additionally, we find that experienced developers seem to be more likely to reuse the knowledge on SO. Moreover, we find that the code reuse ratio in bug-related commits (6.67%) is slightly higher than that of in non-bug-related commits (6.59%). Furthermore, we also find that the code reuse ratio (14.44%) in Java class files that have undergone multiple modifications is more than double the overall code reuse ratio (6.32%).

In this paper, we develop the novel approach to design and fabricate dielectric elastomer (DE) actuator integrating with 3D printed flexible structures, demonstrating large deformation and multi-functionalities. This technique facilitates the combination of complex soft structures fused on the DE membrane without any extra adhesive. Based on the DE actuator, a soft gripper has been fabricated and characterized in terms of bending angle and blocked force. Finite element method (FEM) simulations precisely predict the electromechanical behaviors, guiding the design of the soft actuator. With optimal design, the finger-like soft actuator can generate large actuation with the bending angle about of 128 °. This study can guide the fabrication and modeling of highly designable and customized DE actuators, which are promising in the applications of soft robotics, flexible electronics, and medical devices.

Endowing the animals with agile actions, natural muscle functions as a soft actuator, which is powered by chemical reactions of metabolism and controlled by electrical nerve-signals. Inspired by natural muscle, various types of soft chemical machines (SCM) have been recently developed, possessing advantages of light weight, fast actuation, compact integration, high power and low noise. In this paper, we propose a composite structure as a soft chemical engine (SCE), which is driven by the chemical decomposition of hydrogen peroxide ( H 2 O2). The SCE directly converts chemical energy into mechanical work, achieving excellent performance of large actuation ( ∼ 33% volume expansion) and fast response ( ∼ 1 s). We advance the SCE with excellent performance to a soft chemical machine (SCM) with well-controlled functions, as a mechatronic control system. The soft robot possesses robust control with untethered operation and stable actuating cycles. We develop a model for the locomotion mechanisms, revealing that optimized mechatronic controls can significantly enhance the performance of SCM.

Soft active materials have been widely studied due to their unique attributes of high compliance, various functions and multi physics coupling effects. As a typical soft active material, dielectric elastomer (DE) is promising in various applications, possessing the advantages of large voltage-induced actuation, fast response, lightweight, low cost and high biocompatibility. Utilizing the good performance of large actuation and high compliance, dielectric elastomer is an idea material to drive bio-inspired robot as the artificial muscle. This paper has designed a Manta Ray inspired robotic fish. Utilizing the large actuation of DE membrane, the robot achieves the coupling propulsion of flapping and undulatory motions. The electronics of power and control have been co-fabricated in the body of the robot. The robot achieves good mobility and high environmental adaptability based on its fully soft and transparent structure. The experimental results and design principle of this paper may guide the future design and application of “soft-rigid” co-existed robots and bio-inspired robots.

Eg can be calculated by the equation: Eg (eV) = 1240 / λg. However, the method to determinate λg value is not uniform in different literatures. In this paper, we used the mostly common method to determinate the value of λg , namely the intersection point of the curve tangent to the ultraviolet absorption long wave direction and the baseline. With the values of λg in Figure 4, we calculated Eg values which were listed in Tables 1. From Table 1, it can be seen that the value of Eg has no obvious relation to anodization voltage while anodization duration was kept at 10 min.;Eg can be calculated by the equation: Eg (eV) = 1240 / λg. However, the method to determinate λg value is not uniform in different literatures. In this paper, we used the mostly common method to determinate the value of λg , namely the intersection point of the curve tangent to the ultraviolet absorption long wave direction and the baseline. With the values of λg in Figure 5, we calculated Eg values which were listed in Tables 2. From Table 2 it can be seen that the value of Eg decrease with the increase of anodization duration while voltage was kept at 100 V. It means less energy is needed to create the charge transfer transition.

Electric vehicles (EV) represent a key technology to achieve a low-carbon transportation objective, whist induction motors are one of the promising topologies. The reliability of these machines is crucial to minimize the downtime, cost and unwanted human lives. Although several techniques are utilized in the condition monitoring and fault detection of electrical machines, there is still no single technique that provides an all-round solution to fault detection in these machines and thus hybrid techniques are used widely. This paper presents a novel non-invasive optical fiber technique in condition monitoring of induction machines and in the process detecting inter-turn short circuit faults. Owing to optical fiber’s immunity to magnetic flux, a composite FBG-T sensor formed by bonding a giant magnetostrictive transducer, Terfenol-D, onto a fiber Bragg grating is utilized to sense machines’ stray flux as a signature to determine the internal winding condition of the machines. A tri-axial auto datalogging flux meter was used to obtain the stray magnetic flux and test results obtained via LabView were analyzed in MatLab. Experimental and numerical results agree with each other and how that the FBG-T sensor accurately and reliably detected the short-circuit faults. Bragg shifts observed under short-circuit faults were in 100s of picometre range under various operating frequencies compared to the mid-10s of picometre obtained under healthy machine condition. These provide much promise for future EVs.

The deep sea remains the largest unknown territory on Earth because it is so difficult to explore1–4. Owing to the extremely high pressure in the deep sea, rigid vessels5–7 and pressure-compensation systems8–10 are typically required to protect mechatronic systems. However, deep-sea creatures that lack bulky or heavy pressure-tolerant systems can thrive at extreme depths11–17. Here, inspired by the structure of a deep-sea snailfish15, we develop an untethered soft robot for deep-sea exploration, with onboard power, control and actuation protected from pressure by integrating electronics in a silicone matrix. This self-powered robot eliminates the requirement for any rigid vessel. To reduce shear stress at the interfaces between electronic components, we decentralize the electronics by increasing the distance between components or separating them from the printed circuit board. Careful design of the dielectric elastomer material used for the robot’s flapping fins allowed the robot to be actuated successfully in a field test in the Mariana Trench down to a depth of 10,900 metres and to swim freely in the South China Sea at a depth of 3,224 metres. We validate the pressure resilience of the electronic components and soft actuators through systematic experiments and theoretical analyses. Our work highlights the potential of designing soft, lightweight devices for use in extreme conditions. A free-swimming soft robot inspired by deep-sea creatures, with artificial muscle, power and control electronics spread across a polymer matrix, successfully adapts to high pressure and operates in the deep ocean.

Dielectric elastomers (DEs) is one of the promising artificial muscle for soft robots and flexible devices. As one of the key issues for practical applications, the control of DE actuators remains challenging due to the large actuation, electromechanical coupling, and viscoelastic dissipation. Feedforward control and proportional integral derivative (PID) feedback control are recently studied for the control of DE actuators. The control performance is still limited due to the complex dynamic behavior of DE actuators with both nonlinearities and modeling uncertainties. This paper proposes a model-based feedback control for DE actuator, considering nonlinearity of large deformation, electromechanical coupling, and the modeling uncertainties. A nonlinear motion model is proposed and verified by parameter identification experiments. Based on the nonlinear model, we demonstrate a robust control strategy including nonlinear model compensation and robust feedback to decrease the tracking error. The experimental results verify that the control strategy possesses excellent validity to the DE actuator with improved performance compared to the previous strategy of feedforward and PID feedback control. The system design and control strategy of this paper may guide the future design and application of DE actuators, soft robots, and flexible devices.

Compared to robots and devices made of rigid components, soft robots and flexible devices driven by soft active materials possess various advantages including high adaptability under extreme environment and compatibility with a human. Dielectric elastomer (DE) membrane, which is commonly used in building soft actuators, can achieve large actuation by the combined loadings of voltage-induced Maxwell stress and fluidic pressures (pneumatic and hydraulic pressure). This paper proposes a pneumatic–hydraulic coupled electromechanical actuator (PHCEA), which exhibits strong coupling effect of electromechanical actuation (the Maxwell stress on DE membrane), pneumatic and hydraulic pressures. Considering the moving boundary and state transition, a computational model has been developed to investigate the coupling behaviors of the PHCEA. The numerical result by this model is in accordance with the experimental measurements. The combination of experimental data and the theoretical result indicates that the state transition and moving boundary separate the potential region of electrical breakdown and mechanical damage. This model can be utilized as a practical method to characterize the performance and guide the design of soft devices. The experimental setup and computational method of the PHCEA bring new insights into the fabrication and characterization of soft robots, adaptive optics, and flexible bio-medical devices. The PHCEA possesses wide applications in underwater robots, soft muscles, and microfluidics systems. It can serve as the gas bladder of soft swimming robots, the soft actuator of hydraulic–pneumatic coupling systems, and the gas–liquid valve of flexible microfluidics systems.

With the promotion of the Internet, people can easily retrieve various kinds of education resources on the web. However, current education resources sharing platforms do not support the resources retrieval through the visual information. Therefore, we need to classify the resources which are related to visual characteristics into several categories. In this paper, we propose a novel classification method for resources on Netpad[ http://www.netpad.net.cn/]. We extract the important visual features including graphics features and text features. Then, we use the random forest algorithm to train a valuable model. The results of the experiments indicate that, using graphics features and text features, most of the data are classified correctly, which means that our proposed method can solve the classification problem of Netpad effectively.

Aiming at the GNSS data resolving process and the network RTK positioning algorithm for the multisystem of GPS/BDS/GLONASS, C# and C++ programming were used to develop the resolving software of fast positioning for BeiDou post-mission Network RTK. The software supported self-defined resolving time and could resolve three dimensional user coordinates in a short time. The software was tested with the measured data from the BeiDou high precision reference station network in Guangxi and compared with the TBC+COSA_GPS processing software. And the results show that the proposed software could provide rapid positioning results for users with a centimeter-level precision.

Compared to traditional education resource, Interactive Education Resource (IER) includes dynamic content to interact with users in order to enhance comprehension. The contents of IERs are relatively complex because of its dynamic feature. Exploring IERs and understanding its content during resource search become time-consuming. In this paper, we propose a preview generation approach based on automated software testing and image processing. Our approach first analyzes IERs to collect interactive elements and the event list. Based on the interaction related information, our approach simulates user actions and record snapshots step by step. Our approach compares snapshots to generate an image including the basic content, interaction region and dynamic contents. The image is used as the overall preview and the animation of snapshots collected during simulation is used as detail preview of the IER. In the experiment, we evaluate the completeness, correctness, and comprehension of the preview. The experiment result shows that the preview can be used to provide most information in the resource correctly and easy to understand. Our approach can save time for users in understanding the IERs. Keywordspreview generation; interactive education resource; dynamic content collage

Soft chemo-mechanical (SCM) machines convert chemical energy into mechanical energy. They have the advantages of fast actuation and compliant deformation and possess wide applications in soft robots and flexible smart devices. Using experiments and theoretical modeling, this paper investigates the chemo-mechanical energy flows and the energy conversion cycle in the pressure and volume (P–V) plane of an SCM machine consisting of a soft membrane and cylindrical chambers. The machine generates 16.1 mJ of mechanical energy per cycle. We study heat dissipation as the key issue affecting the conversion efficiency. The states of the conversion cycle calculated from mechanical modeling fit well with those measured experimentally. The design principles and the theoretical methods can be used to guide the fabrication and characterization of SCM actuators and robots.

Dielectric elastomer (DE) membranes are able to self-deform with the application of an electric field through the thickness direction. In comparison to conventional rigid counterparts, soft actuators using DE provide a variety of advantages such as high compliance, low noise, and light weight. As one of the challenges in the development of DE actuating devices, tuning the electromechanical actuating behavior is crucial in order to achieve demanded loading paths and to avoid electromechanical failures. In this paper, our experimental results show that the electromechanical loading conditions affect the actuating behaviors of the DE. The electrical actuating force can be tuned by 29.4% with the control of the electrical charging rate. In addition, controllable actuations have been investigated by the mechanical model in manipulating the electromechanical loading rate. The calculated results agree well with the experimental data. Lastly, it is believed that the mechanisms of controlling the electromechanical...