Miracle-dz/UniFAR-FTUs huggingface dataset:
A Delay-Line DPWM Architecture With Compensation Module and Delay-Adjustable Unit Based on DLL

Due to the increasing resolution, the duty cycle in digital pulsewidth modulation (DPWM) is affected by the variation of external clock frequency or temperature, and the time error becomes larger and larger, even reaches a few nanoseconds. The increment of the duty cycle will affect the regulation performance of the converter and the output of DPWM. In this article, a delay-line DPWM architecture with a compensation module and a delay-adjustable unit based on delay-locked loop is proposed. The delay-adjustable unit is realized by using a multiplexer and some delay paths with different delay times, which effectively reduces the influence of temperature or the frequency changes from the input clock. Furthermore, a time compensation method is used to reduce the error generated by the critical path delays. A 10-bit DPWM with 781-kHz switching frequency is achieved on A-7 (xc7a100tfgg484) Xilinx FPGA, and the time error of the architecture decreases to around 500 ps. The duty cycle range is from 1.63% to 98.44%.
TTLCache: Taming Latency in Erasure-Coded Storage Through TTL Caching

Distributed storage systems are known to be susceptible to long response time, and higher latency leads to a reduction in customers satisfaction. An elegant solution to reduce latency in such systems is through two methods - having redundancy in contents at the storage nodes, and adding a cache close to end-users. Redundancy could be added using an erasure code because of its high resiliency with low storage overhead. It is important to quantify the performance of distributed storage systems in the presence of redundancy and caching, which is the focus of this work. This paper proposes a framework for quantifying and jointly optimizing mean and tail latency in erasure-coded storage systems with edge-caching capabilities. A novel caching policy for caching contents in erasure-coded storage systems, called time-to-live (TTLCache), is proposed. Using TTLCache policy and probabilistic server-selection techniques, bounds for mean latency and latency tail probability (LTP) are characterized. A convex combination of both metrics is optimized over the choices of probabilistic scheduling and TTLCache parameters using an efficient algorithm. In all tested cases, the experimental results show the superiority of our approach as compared to the state of the other algorithms and some competitive baselines. Implementation in a real cloud environment is further used to validate the results.
Evaluation of Apically Extruded Debris and Irrigants during Root Canal Preparation using Different Rotary Instrumentation Systems:An In-vitro Comparative Study

Background: Different instrumentation systems and techniques are used in the instrumentation of the root canal system which can result in debris formation that may be extruded beyond the apical foramen and cause post-operative pain. Aim of the study: Aim of the current study was to compare the amount of apically extruded debris and irrigants during instrumentation using 2 reciprocating single file systems (WaveOne Gold, Reciproc blue) and 2 continuous rotation file systems (ProTaper Gold, 2Shape) and comparing them to the control group (ProTaper Universal). Materials and Methods: Total 50 palatal roots of freshly extracted human maxillary first molars were collected for this study. Teeth were decoronated to a unified length of 15 mm, and then pushed through a pre-perforated rubber cap of pre-weighed glass vial then the root-cap complex was fitted on a glass vial and rubber dam ligated with dental floss was used to cover the glass vial for preventing the coronally extruded debris and irrigants from contaminating the external surface, gauge 25 needle was inserted parallel to the root surface through the rubber dam and cup. Samples were then randomly divided into 5 groups. Results: Data obtained were statistically analyzed using One Way ANOVA and LSD tests. The result showed that all groups resulted in apical extrusion of debris and irrigants, as it showed that the 2Shape Group B, Wave One Gold Group C and Reciproc blue Group D are statistically comparable, while ProTaper Gold Group A and ProTaper Universal Groups E showed statistically significant difference (p<0.05). Conclusions: All of the systems resulted in apical extrusion. There was no influence of kinematic movements on apical extrusion. The 2shape file system produced the least amount of apical extrusion while the ProTaper Universal showed the greatest amount.
Adaptive Backstepping Control with Extended State Observer for Wheeled Mobile Robot

In this paper, the adaptive backstepping controller is designed based on kinematics and dynamics model of the wheeled mobile robot (WMR). Based on backstepping control theory, an adaptive law is designed to reduce the influence of the control system because of the internal disturbance caused by uncertain or unknown parameters of system and the external disturbance caused by environmental factors. Lyapunov stability theory is applied to prove the stability of the adaptive controller. In order to further reduce the influence of disturbance on the control performance, the extended state observer (ESO) is introduced to observe the disturbances of linear speed and angular speed which compensate the control output value of adaptive controller. Simulation results show that the proposed control method can adapt disturbance of the system and has a good performance on trajectory tracking.
Can a Learning Companion Be Used to Continue Teaching Programming to Children Even During the COVID-19 Pandemic?

Learning how to program in Primary Education has attracted significant research in recent years. It is unclear though how programming environments and languages should be adapted to children to achieve better learning and use, but one trend seems to be the use of Scratch. The question in this paper is what programming environment can be used to continue teaching programming to children who have already been taught Scratch for years. This paper’s proposal is that students aged between 10 and 12 can benefit from interacting with a friendly learning companion using p-code such as Alcody. The hypothesis is that students (aged between 10 and 12) with a knowledge of Scratch will be able to significantly improve their scores by using a learning companion to teach them how to program even during the COVID-19 pandemic. To check the hypothesis, an experiment was carried out during the 2019/2020 academic year with 137 students in Ecuador. A significant improvement in the scores of the students was recorded together with high satisfaction.
Monocular Visual SLAM based on VGG Feature Point Extraction

Significant progress has been made in the field of visual SLAM (Simultaneous Localization and Mapping). However, the localization accuracy of visual SLAM can be significantly reduced in low-texture and illumination-changing environments. To solve these problems, an enhanced visual SLAM algorithm based on VGG (Visual Geometry Group) network was proposed in this paper. Firstly, the VGG network for feature point extraction was incorporated into the visual odometry (VO) to achieve robust camera pose estimation. Secondly, an automatic corner annotation method was adopted to set up the training database, which could reduce the workload of data annotation. Thirdly, to make the backend optimization more suitable for the VGG based VO, the BA (bundle adjustment) optimization process was improved. Experimental results showed that, the proposed visual SLAM method outperformed the mainstream ORB-SLAM (Oriented FAST and Rotated BRIEF SLAM) method, in terms of the number of effective feature points, the robustness of feature matching process to light changes, and the accuracy of robot pose estimation.
Measuring and Separating Conducted Three-Wire Emissions From a Fault-Tolerant, NPC Propulsion Inverter With a Split-Battery Using Hardware Separators Based on HF Transformers

Conducted emissions on the traction battery's power cables in EVs must be limited to avoid unwanted electromagnetic interference (EMI). When designing an EMI filter, it is advantageous to have information of the common mode (CM) and differential mode (DM) noise levels. This article deals with the measurement and separation of the dc side's three-wire DM/CM noise of a fault-tolerant three-level neutral-point-clamped (NPC) inverter with a split-battery system. Two hardware separators, based on small-circuit highfrequency transformers, were developed to identify the dc side's CM, line-DM, and phase-DM noise levels. Their characterized CM and DM rejection ratios for the frequency range from 150 kHz to 110 MHz are at least $-$33 and $-$21 dB, respectively. The separated noise of the NPC inverter was measured, using an inductive load, when operating the inverter with three-level and two-level modulation, resembling normal operation and a possible operation under fault, respectively. A simple three-wire CM model of the used testbed and the DM power module oscillation were derived to validate the separated noise's resonance peaks/valleys. It has been seen that the CM noise is dominant, especially below 10 MHz, except for the power module oscillations. Furthermore, when using the two-level modulation, in the case of a clamping diode fault, the noise levels are increased by about 3 dB.
Overview of Transformerless Photovoltaic Grid-Connected Inverters

Transformerless grid-connected inverters (TLI) feature high efficiency, low cost, low volume, and weight due to using neither line-frequency transformers nor high-frequency transformers. Therefore, TLIs have been extensively investigated in the academic community and popularly installed in distributed photovoltaic grid-connected systems during the past decade. This article analyzes and summarizes the state of the art of TLI techniques, three rules of maintaining constant common-mode voltage (CMV) of TLIs at switching frequency have been concluded from a generic CMV analysis model at the beginning. Second, suppression methods of leakage current (LC) and dc current injection (DCCI), so-called two key challenges for first-generation TLIs, have been classified and discussed in detail, respectively. Finally, future trends and some challenges of TLIs based on wide bandgap devices named second-generation TLIs have been presented in this article.
A programming language for Developing APPs of Insect Intelligent Building

To support the development of applications in a novel decentralized computing structure, i.e., Insect Intelligent Building (I2B) platform, the key enabler is to design a proper programming language for specific domains. Existing researches are either unwieldy or unfriendly for developing the domain-oriented applications. This paper aims to facilitate the development of such applications and reduces the programming difficulty of programmers. We propose Touch, a textual programming language for I2B APPs(applications), which provides a high-level abstraction of I2B elements. Specifically, we establish the programming conceptual architecture (i.e., Individual, Neighborhood, and Domain ) and programming mechanism of I2B APP. Moreover, the specific language elements and formal syntax of Touch are designed. Evaluation results show that Touch can effectively support the development of I2B APP and greatly reduce the size of the program.
Vibration Suppression of a Flexible Beam Based on a Color Tracking Camera and ADC Method

In this paper, an OpenMV camera with color tracking algorithm to sense object displacement is used to achieve the vibration suppression of a flexible beam. First, we write a program that tracks the dynamic position of the center of a color block, and provides the communication protocol for sending position coordinates through the serial port. Then we designed a vibration suppression experiment system based on servo motion module and real-time Linux operation system. Finally, an adaptive disturbance canceller (ADC) algorithm was used to conduct vibration suppression experiments on the flexible beam. After the top of the beam was disturbed by a 10mm displacement, the amplitude of the beam is attenuated by 90% at 5s, while the free attenuation is 60%. Beam top is stationary after 20s, while the free attenuation is more than 35s. The experimental results show that the vibration of the flexible beam is well suppressed.
Study on Inter-temporal Pricing to Suppress Negative Network Externalities of Merchants in Two-Sided Markets

The problem of dishonest transactions in two-sided markets is increasingly prominent, and its governance mechanism needs to be improved. Pricing strategy is an effective means of platform governance, which can restrain the negative network externalities caused by dishonest transactions. By using the inter-temporal analysis method, this paper analyzes the influence of network externalities in different periods on platform pricing and regulatory costs. The research shows that: from the perspective of platform profit maximization, (1) The greater the positive network externalities of merchants, the lower the platform charges merchants; (2) The greater the negative network externalities caused by dishonest transactions, the higher the platform charges merchants; (3) The greater the network externalities of consumers to merchants, the higher the platform charges merchants. Finally, the influence of cross network externality on platform pricing, platform supervision cost, number of both sides of the platform and platform profit is analyzed by simulation. This provides suggestions for the platform to control merchants' dishonest transaction behavior through pricing.
Implementation of Control Strategy for Parallel Operation of Three Phase Inverters

This paper presents a control technique allowing parallel operation of 3-phase voltage source inverters. The outer control loop that ensures appropriate loads sharing, is based on the droop control principles with implemented virtual inductance. As the inner control loop a voltage regulation topology using values transformed into Direct-Quadrature (D, Q) synchronous reference frame is implemented. The dynamic and static behavior of whole control system was verified by simulations. Prepared control software based on described strategy was implemented into control systems of the three phase inverters forming a parallel system. The whole parallel system was verified by experimental measurements.
Soft Microtubule Muscle-Driven 3-Axis Skin-Stretch Haptic Devices

In the real world, people heavily rely on haptic or touch to manipulate objects. In emerging systems such as assistive devices, remote surgery, self-driving cars and the guidance of human movements, visual or auditory feedback can be slow, unintuitive and increase the cognitive load. Skin stretch devices (SSDs) that apply tangential force to the skin via a tactor can encode a far richer haptic space, not being limited to force, motion, direction, stiffness, indentation and surface geometry. This paper introduces novel hand-worn hydraulic SSDs that can induce 3-axis tangential forces to the skin via a tactor. The developed SSDs are controlled by new soft microtubule muscles (SMMs) which are driven by hydraulic pressure via custom miniature syringes and DC micromotors. An analytical model is developed to characterize the responses of SMM output in terms of force and elongation. A kinematic model for the motion of the 3-axis SSD is also developed. We evaluate the capability of the tactor head to track circular reference trajectories within different working spaces using an optical tracking system. Experimental results show that the developed SSDs have good durability, high-speed, and can generate omnidirectional shear forces and desired displacement up to 1.8 N and 4.5 mm, respectively. The developed SMMs and SSDs created in this paper will enable new forms of haptic communication to augment human performance during daily activities such as tactile textual language, motion guidance and navigational assistance, remote surgical systems, rehabilitation, education, training, entertainment, or virtual and augmented reality.
Effect of Air Gap Size on Parameters of High Speed Switched Reluctance Motor

This paper deals with an analysis of the air gap size effect on the other parameters of high speed Switched Reluctance Motor (SRM) as average static torque, torque ripple, winding losses, iron losses, mechanical losses, output power and efficiency. At the beginning, there is introduction about state of the art of high-speed machines. The following section presents the state of the motor design before this analysis. Numerical and analytical models and design procedures are used. Subsequently, these procedures are presented. Finally, the obtained results are presented and commented.
Observer-based distributed event-triggered control of Markov linear system over saturation sensor network

Under the consideration of distributed adaptive event-triggered communication scheme and cyber-attacks, the paper focuses the observer-based H∞ control issue for Markov jump linear systems over stochastic saturation sensor networks. To describe physical systems with abrupt variations, the system parameters and the network structure composed of a group of sensor nodes are modeled by Markovian switching topologies. A distributed adaptive event-triggered mechanism is designed to reduce the occupancy of the limited network resources. Based on randomly occurring cyber-attacks, a novel observer collected coupled transmission signals from multi-channel is first proposed to estimate unavailable state variables and exploited in the feedback protocol. Furthermore, a sufficient condition is derived to guarantee the stability of the built model with a prescribed performance index. Simultaneously, a co-design method for observer and controller gain matrices is proposed. Finally, the effectiveness of the model is illustrated by a numerical simulation example.
Linear Active Disturbance Rejection Control for Propeller-Driving System based on Model Information Compensation

In order to get a better performance from the Linear Extended State Observer (LESO), a Linear Active Disturbance Rejection Control (LADRC) strategy is proposed based on the Unscented Kalman Filter (UKF) identification. The UKF, with high accuracy of estimation for nonlinear distribution, is applied to identify the system information so as to provide the design parameter b0 of the LADRC. In order to avoid the problem that the covariance matrix is non-positive and improve the numerical robustness, singular value decomposition is usedto instead of Cholesky decomposition in the UKF. It improves the ability of the LESO, and hence the performance of LADRC by reducing the uncertainty of the controlled system. Taking into account sensor noise, a tracking-differentiator is introduced to the LESO to get a better control performance. Both the LADRC based on the UKF identification and the traditional LADRC are applied to the propeller-driving system and compared in this paper. The simulation and experiment results both show that the proposed method has better control effect compared with the traditional LADRC, and the estimation ability of the LESO is stronger.
Adaptive Fuzzy Sliding Mode Control for Decoupled Uncertain Underactuated Systems

In this work, a decoupled adaptive fuzzy sliding mode control method for a class of underactuated systems with unknown terms is proposed. Firstly, the underactuated system is decoupled into two second-order subsystems, which are referred to the actuated and the underactuated parts, and the sliding manifold of the underactuated subsystem is implemented into the actuated subsystem through an inverse-tangent saturation function. Secondly, a sliding mode controller by decoupled method is designed. Then an adaptive fuzzy algorithm is presented to estimate the unknown terms of the system, moreover, the estimated upper bound of the fuzzy modeling error are solved by the adaptive algorithm. Finally, the stability analysis of the closed-loop system is verified by the Lyapunov stability theory. Simulation results on the overhead crane system are given to show the effectiveness of the proposed method.
Real-time Implementation and Application of Hodgkin–Huxley Model in Embedded System of Closed-Loop Electrophysiology Platform

The Hodgkin–Huxley (HH) model can simulate the process of neuron pulse delivery, and can reasonably explain each step in the process. In this study, we use a microcontroller based on the Advanced RISC Machines (ARM) core to implement the Hodgkin-Huxley model, and use four microcontrollers to implement three ion channels and an external current channel. The hardware experimental results and MATLAB simulation results are exactly the same. Studies have shown that the dynamic characteristics of the neuron model implemented on a microcontroller based on the ARM Cortex-M4 core can meet real-time computing requirements. In addition, due to the different conditions of patients, its external stimulation current and the reversal potential of each ion channel has a significant effect on the neuron release process. By changing the parameters on a single microcontroller, we adjusted and tested it on the hardware platform to show the experimental results more clearly and conveniently. The results show that changes in the stimulation current will affect the firing state of the neurons, and changes in the reversal potential of each ion channel will affect the firing frequency of the HH neuron model.
Adaptive Control for Stochastic Nonlinear Systems With Quantized States

In this paper, adaptive control problem is investigated for stochastic nonlinear systems with quantized states. Compared with the existing works, the considered system is more general which contains a deterministic nonlinear term and a stochastic disturbance in each channel. In order to handle the high order nonlinearities, we present a new technique which makes the partial derivative of virtual control law become a constant, this makes the adaptive control scheme of state quantization feasible. Then, a new adaptive law is proposed to deal with some completely unknown parameters, which includes an interesting third-order term of the parameters. Finally, simulation results demonstrate the efficacy of the proposed schemes.
Electrically Small Spiral PIFA for Deep Implantable Devices

In this paper, a miniaturized implantable circularly polarized spiral Planar Inverted-F Antenna (SPIFA) in the UHF (600-800 MHz) band is presented. This antenna is intended for deep implantable devices such as leadless pacemakers and deep brain stimulation (DBS), which facilitates the reception of RF power from an external transmitter. The antenna is electrically small, with a volume of <inline-formula> <tex-math notation="LaTeX">$\pi \times 5\,\,\tilde {\text{m}} \text{m} \times5\,\,\tilde {\text{m}} \text{m} \times3.2\,\,\tilde {\text{m}} \text{m} $ </tex-math></inline-formula> and a diameter of <inline-formula> <tex-math notation="LaTeX">$0.022\lambda $ </tex-math></inline-formula>. The performance of the proposed antenna in terms of reflection coefficient, realized gain and axial ratio are assessed when accounting for the effects of operating in different types of human body tissues, different biocompatible materials and different thicknesses and depths of the implanted antenna. Finally, the antenna is prototyped and measured in free space, a phantom model, in a cow’s fat and muscle tissues to validate the simulation results, indicating good agreements. A realized gain around −20 dBm is achieved when operating in 50 mm depth in cow’s muscle tissue while having electrically very small dimensions compared to implantable antennas reported in the literature.