Miracle-dz/UniFAR-FTUs huggingface dataset:
Wireless Localization of Spallings in Switch-Rails With Guided Waves Based on a Time–Frequency Method

Guided waves have been studied for monitoring defects on switch-rails. However, few researchers study monitoring of spallings. Previous studies on switch-rail damage detection are not suitable for this kind of damage at the edge of the rail web. In addition, wired configurations have the challenges of power supply and more cost. This paper proposes a time-frequency analysis based algorithm that is used to locate spallings. The algorithm is verified through an improved wireless based structural health monitoring (SHM) platform. The excitation frequency of 108 kHz is chosen as a compromise between larger wave velocity differences and smaller detectable damage sizes. A total of 4 piezoelectric (PZT) devices make up one actuator-sensor array. 2 PZT devices are placed at 2 sides of the rail web and both of them have the same excitation direction. The other 2 devices are mounted at the top of the rail web to measure spalling induced waves according to the cloud charts. The arrival time, frequency, and wave velocity features of the main modes in transmission and reflection waves are extracted. Then these parameters are substituted in the proposed algorithm to predict the spalling location. Simulation and epoxy bonding based experimental results show that the proposed method can identify a 15 mm length spalling at different locations. Finally, attention is paid to the mode identification errors that influence spalling localization. The effects of curvature on guided waves in switch-rails are analyzed and considered to be the cause of the errors.
Dual-Band Reduced-Order Model of an HVDC Link Embedded Into a Power Network for EMT Studies

This paper presents an approach to obtain reduced-order models for power networks involving power electronic converters (PEC) via the frequency-domain balanced realizations (FDBR) technique. PECs play an essential role in power processing and energy conversion in modern electrical networks, such as the interconnection of renewable generators, HVDC links, and active filters. Integration of PECs into dynamic equivalents needs model-order reduction (MOR) in both low- and high-frequency ranges to account for both slow and fast dynamics due to the network and switching natures. The objective of the FDBR technique is to obtain an internally balanced system, i.e., an equally controllable/observable system, that can be reduced according to its dominant dynamics within the limited frequency bandwidths. This allows accounting for specific band-limited phenomena, such as those generated within a power network caused by PECs, which is the focus of this paper. The results show that faster yet accurate simulations are achieved by reduced-order models through FDBR compared to their full-order counterparts.
On the Stability of Power Electronics-Dominated Systems: Challenges and Potential Solutions

The modern power system is becoming more complicated due to the ever increasing penetration of power electronics, which is referred to as a power-electronics-dominated system (PEDS). In this case, the analysis, control, and operation of the entire power system should tone with the energy-paradigm transition pace, where the challenges should be properly tackled. After the brief introduction of grid-connected converters, this article explores stability challenges of PEDSs, especially on the low inertia issue and multitimescale characteristics, as well as the dynamics when connected to weak grids. The low inertia issue is considered as one of great challenges that power electronics introduce to the conventional power grid. Accordingly, the stability issues of PEDSs are discussed. The exploration reveals that the multitimescale coupling among various control loops and the mutual effects of multiple converters demand much more attention than ever before. The coordinated control of converters for the global stability of PEDSs is also summarized, part of which offers the possibility to solve the inertia problem. This article serves as an inspiration on potential solutions to these issues. In order to provide a more intuitive impression of the inertia problem in PEDSs, a case study is exemplified to highlight the analysis and discussion.
Autonomous Load Regulation Based Energy Balanced Routing in Rechargeable Wireless Sensor Networks

Recent progress in wireless charging technologies has greatly promoted the development of rechargeable wireless sensor networks (RWSN). The network lifetime of RWSN can be commonly extended through routing strategy and wireless charging technology. However, the node accepts the relay request of its neighbor unconditionally, and it cannot remove its overload on its own in a timely manner in traditional routing strategies. The energy balancing efficiency of the network may be limited by this passive mechanism, which poses a great challenge to obtaining optimal joint efficiency of routing and charging strategies. In this paper, we propose an autonomous load regulation mechanism-based energy balanced routing algorithm (ALRMR) for RWSN. In addition to an efficient framework of joint wireless energy transfer and multi-hop routing where the routing strategy is adapted to the charging scheme, an innovative load regulation mechanism is proposed. Under this mechanism, each node can actively adjust its own load by controlling its relay radius. The simulation demonstrates the advantages of our algorithm for energy balance efficiency and improving the network lifetime through the charging scheme and the innovative mechanism.
Development and evaluation of the HaptiWatch with a smart notification system

In this study, we developed a new type of smartwatch, the HaptiWatch, which has notification functions that are not present in analog watches that lack a high‐resolution display. The HaptiWatch also has a priority‐filtering function that distinguishes notifications by their importance. Notification information is encoded as light and haptic pulses which allow users to recognize the type and importance of the notification without having to see the watch. To evaluate the user experience (UX) of the HaptiWatch's new notification system, a comparative study was conducted together with the notification system of the Samsung Galaxy Gear S3 Frontier, a well‐known smartwatch. The UX evaluation results indicate that the notification system of the HaptiWatch provides an experience that is comparable to that of the Gear S3.
A 8.2-pW 2.4-pA Current Reference Operating at 0.5 V With No Amplifiers or Resistors

This brief presents an ultra-low-power (ULP) current reference circuit based on <inline-formula> <tex-math notation="LaTeX">$V_{th}$ </tex-math></inline-formula> (threshold voltage), which consumes pico-watt of power under 0.5V supply voltage. Compared to traditional current references based on threshold voltage, this design uses no amplifier, thus friendly scaling and simple structure are achieved simultaneously. In order to save area, the huge resistor is replaced by a gate-leakage MOS transistor. The proposed circuit is designed in a 40nm CMOS process. The minimum supply voltage is 0.5V. Post simulation results show that the power consumption is only 8.2pW at 0.5V <inline-formula> <tex-math notation="LaTeX">$V_{DD}$ </tex-math></inline-formula> at room temperature. According to our knowledge, this is the smallest power consumption compared to prior works, thanks to its simple structure. Under process + mismatch Monte-Carlo simulations, the temperature coefficient after trimming is 18.6ppm/°C over 0°C to 85°C. The core area is only 0.00025mm<sup>2</sup> in layout. Apart from the 40nm process, this circuit is also designed in a 130nm process to demonstrate the robustness under different processes.
Behavioural Fault tolerant control of an Omni directional Mobile Robot with Four mecanum Wheels

This paper analyses the four-mecanum wheeled drive mobile robot wheels configurations that will give near desired performance with one fault and two faults for both set-point control and trajectory-tracking (circular profile) using kinematic motion control scheme within the tolerance limit. For one fault the system remains in its full actuation capabilities and gives the desired performance with the same control scheme. In case of two-fault wheels all combinations of faulty wheels have been considered using the same control scheme. Some configurations give desired performance within the tolerance limit defined while some does not even use pseudo inverse since using the system becomes under-actuated and their wheel alignment and configurations greatly influenced the performance.
A Power-Factor-Corrected LLC Resonant Converter for Electric Vehicle Charger Using Cuk Converter

This article presents an improved power quality Cuk-converter-fed isolated LLC resonant converter for an electric vehicle battery charger (EVBC), intended typically to charge a small two- or three-wheel-driven electric vehicle (EV) using up to 20-Ah battery. The proposed topology consists of two converters, comprising of the first stage for power factor correction (PFC) and the second stage for effective charging of the EV battery using a constant-voltage and constant-current mode control algorithm. In the first stage, the Cuk converter performs PFC by operating in the continuous conduction mode of the primary inductor, while the LLC resonant converter converts the dc-link voltage to the isolated dc voltage required for the EVBC. The proposed converter uses a frequency control algorithm to actively vary the intermediate dc-link voltage based on the state of charge of the battery leading to reduced turn-off losses in the LLC converter switching devices. The proposed converter is designed and simulated in MATLAB. Simulated results are analyzed and discussed in detail. Finally, a 580-W 10-A experimental prototype of the EVBC is developed, and test results are presented to demonstrate the effectiveness of the proposed topology. The proposed converter exhibits excellent power quality indices adhering to the IEC-61000-3-2 international standard.
Toward Time-Optimal Trajectory Planning for Autonomous Ship Maneuvering in Close-Range Encounters

Ship intelligence has been a hot topic in recent years. How to achieve autonomous maneuvers in a complex marine environment in a safe, efficient, and low-cost manner is a fundamental task that ocean engineers face. This paper presents a two-stage trajectory planning scheme to address the minimum-time maneuvering problem in close-range encounters. The scheme is robust and versatile, as it can deal with the complex spatial variability, such as sea current, state constraints, marine traffic, and physical constraints, of close-range maneuvering. In the first stage, a directed graph with variable length is generated according to the sea current distribution. A wavefront search is applied on the graph to explore the reachability, the cost of state constraints, and the risk of collision. After a discrete solution has been found, the second stage involves searching for a smooth solution. A Bézier curve based parameter optimization approach is proposed to get rid of limited moving directions in the directed graph and explore around the discrete path. The result will be a near-optimal, smooth path. The proposed scheme has been tested to solve the Zermelo's ship steering problem and several other close-range maneuvering problems. The results demonstrate that the scheme is efficient in generating smoothed minimum-time trajectories for surface vessels when maneuvering in close-range encounters.
An Evaluation between Global Appearance Descriptors based on Analytic Methods and Deep Learning Techniques for Localization in Autonomous Mobile Robots

In this work, different global appearance descriptors are evaluated to carry out the localization task, which is a crucial skill for autonomous mobile robots. The unique information source used to solve this issue is an omnidirectional camera. Afterwards, the images captured are processed to obtain global appearance descriptors. The position of the robots is estimated by comparing the descriptors contained in the visual model and the descriptor calculated for the test image. The descriptors evaluated are based on (1) analytic methods (HOG and gist) and (2) deep learning techniques (auto-encoders and Convolutional Neural Networks). The localization is tested with a panoramic dataset which provides indoor environments under real operating conditions. The results show that deep learning based descriptors can be also an interesting solution to carry out visual
Design and Characterization of Micro-LED Matrix Display With Heterogeneous Integration of GaN and BCD Technologies

Micro-light-emitting diodes (<inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>LEDs) are semiconductor devices that have been shown to have higher luminous efficacy, higher contrast ratio, and higher energy efficiency than existing mainstream technologies based on liquid crystals or organic LEDs (OLEDs). Portable display applications such as wearable devices and head-up display are some of the interesting applications of <inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>LED displays. However, this technology has not yet been mass-produced for commercial devices due to process yields, costs, and manufacturability issues. This article presents a novel technology for the heterogeneous integration of a <inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>LED matrix display with bipolar complementary metal–oxide–semiconductor (CMOS) DMOS (BCD) circuits that could improve manufacturability by eliminating the need for a dedicated bond stack in the bump-bonding process. To validate the concept, custom high-performance, 2-D arrays of parallel-addressed GaN blue <inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>LEDs matrices were fabricated. The individual <inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>LED pixel diameters are 20 and 50 <inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula>, respectively, and the overall dimension of the array is <inline-formula> <tex-math notation="LaTeX">$650~\mu \text{m}^{2}$ </tex-math></inline-formula>. In addition, a <inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>LED display driver-integrated circuit (IC) with a compact size of <inline-formula> <tex-math notation="LaTeX">$3\times 4.4$ </tex-math></inline-formula> mm<sup>2</sup> has been designed, implemented, and verified experimentally for the <inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>LED matrices. Measured output optical power-forward bias current-forward bias voltage (<inline-formula> <tex-math notation="LaTeX">${P}$ </tex-math></inline-formula>–<inline-formula> <tex-math notation="LaTeX">${I}$ </tex-math></inline-formula>–<inline-formula> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula>) curves of the individual <inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>LED pixel are shown. The <inline-formula> <tex-math notation="LaTeX">$4\times 4\,\,\mu $ </tex-math></inline-formula>LED matrix has also been successfully driven using active-matrix driving and display pictures to demonstrate the function of active-matrix driving are presented.
Distributed Predictive Control for Frequency and Voltage Regulation in Microgrids

Distributed control schemes have transformed frequency and voltage regulation into a local task in distributed generators (DGs) rather than by a central secondary controller. A distributed scheme is based on information shared among neighboring units; thus, the microgrid performance is affected by issues induced by the communication network. This paper presents a distributed predictive control applied to the secondary level of microgrids. The model used for prediction purposes is based on droop and power transfer equations; however, communication features, such as connectivity and latency, are also included, thus making the controller tolerant to electrical and communication failures. The proposed controller considers the frequency and voltage regulation control objectives and consensus over the real and reactive power contributions from each power unit in the microgrid. The experimental and simulation results show that the proposed scheme (i) responds properly to load variations, working within operating constraints, such as generation capacity and voltage range; (ii) maintains the control objectives when a power unit is disconnected and reconnected without any user updating in the controllers; and (iii) compensates for the effects of communication issues over the microgrid dynamics.
Unknown Input Observers for Simultaneous Estimation of Vehicle Dynamics and Driver Torque: Theoretical Design and Hardware Experiments

This article investigates a new observer design method to estimate simultaneously both the vehicle dynamics and the unknown driver's torque. To take into account the time-varying nature of the longitudinal speed, the vehicle system is transformed into a polytopic linear parameter-varying (LPV) model with a reduced level of numerical complexity. Based on Lyapunov stability arguments, we prove that the estimation errors of the system state and of the unknown input (UI) are norm-bounded, which can be made arbitrarily small by minimizing a guaranteed $\mathcal {L}_{\infty }-$gain performance. The design of the LPV UI observer is reformulated as an linear matrix inequality-based optimization which can be effectively solved via semidefinite programming. Extensive hardware experiments are carried out under various driving test scenarios to confirm the effectiveness of the proposed observer design. In particular, a comparative study is performed with a widely adopted observer to emphasize the practical interests of the new estimation solution.
Feedline Alterations for Optimization-Based Design of Compact Super-Wideband MIMO Antennas in Parallel Configuration

This letter presents a technique for size reduction of wideband multiple-input–multiple-output (MIMO) antennas. Our approach is a two-stage procedure. At the first stage, the antenna structure is modified to improve its impedance matching. This is achieved through incorporation of an n-section tapered feedline, followed by reoptimization of geometry parameters. Reducing the maximum in-band reflection well beyond the acceptance level of −10 dB creates room for size reduction, realized in the second stage as explicit footprint area minimization with the constraints imposed on the maximum in-band reflection level (|S11| ≤ −10 dB) and element isolation (|S21| ≤ −20 dB). The technique is generic and can be applied to various monopole-based MIMO structures. It is validated using two antenna structures operating from 2.8 to 20 GHz. Various complexities of the tapered lines are also investigated, from n = 1 to 5. To the best of the authors’ knowledge, the obtained footprints (452 and 546 mm2, respectively) are the smallest to date while ensuring acceptable performance, specifically impedance matching, isolation, envelope correlation coefficient (<0.005), and diversity gain (>9.99 dB).
Fast and optimised design of a differential VCO using symbolic technique and multi objective algorithms

In this work, a DVCO has been designed for a 4-bit, 10 MHz VCO based ADC. The noise modelling and analysis of this designed DVCO is carried out using layered determinant expansion based DDD technique. The results obtained using these methods are found to be nearly identical to that of SPICE. However, the computational time has been reduced from 13.7 sec using numerical method (SPICE) to 4.5 sec using DDD technique. Optimisation of the designed DVCO is then carried out using multi-objective optimisation techniques such as IDEA and MOPSO to enhance the performance. Low power and low phase noise at the desired frequency of oscillation were the optimisation goals. For this designed DVCO, IDEA optimisation approach seems to be more efficient than the MOPSO. The optimised DVCO is then simulated at different process corners using SPICE. The designed DVCO has shown improvement in phase noise from −80.3 dBc/Hz to −88.9 dBc/Hz at 1 MHz offset. The power consumption is also reduced from 38.4 mw to 34.5 mw and achieved a target frequency of 3.49 GHz. These improvements in the performance of the DVCO lead to an improvement in the ENOB from 3.6 to 4.2 bit of the designed ADC.
Damping Torque Analysis of DC Voltage Stability of an MTDC Network for the Wind Power Delivery

Conventional damping torque analysis (DTA) is a well-known and widely used method to examine the low-frequency electromechanical oscillation stability of an AC power system. This article expands the conventional DTA for studying the DC voltage stability of an MTDC network. In the article, analysis is carried out to prove that the DTA can be applied to examine the DC voltage stability of MTDC network. Application of DTA can not only reveal the insight about why growing DC voltage oscillations may occur, but also to guide the parameters tuning of control systems of voltage source converters (VSCs). The parameters tuning is to avoid that the damping contributions from the VSCs in the MTDC network are very much varied such that DC voltage instability may occur after some of VSCs are withdrawn from operation. In addition, DTA can also be applied to guide the parameters setting of a current flow controller (CFC) in order to ensure the DC voltage stability of the MTDC network after the CFC is installed. An example MTDC network is used to demonstrate and evaluate the applications of DTA in the article.
White Mensural Manual Encoding: from Humdrum to MEI

The recovery of musical heritage currently necessarily involves its digitalization, not only by scanning images, but also by the encoding in computer-readable formats of the musical content described in the original manuscripts. In general, this encoding can be done using automated tools based with what is named Optical Music Recognition (OMR), or manually writing directly the corresponding computer code. The OMR technology is not mature enough yet to extract the musical content of sheet music images with enough quality, and even less from handwritten sources, so in many cases it is more efficient to encode the works manually. However, being currently MEI (Music Encoding Initiative) the most appropriate format to store the encoding, it is a totally tedious code to be manually written. Therefore, we propose a new format named **mens allowing a quick manual encoding, from which both the MEI format itself and other common representations such as Lilypond or the transcription in MusicXML can be generated. By using this approach, the antiphony Salve Regina for eight-voice choir written by Jerónimo de la Torre (1607–1673) has been successfully encoded and transcribed.