Miracle-dz/UniFAR-FTUs huggingface dataset:
A Universal Blocking-Module-Based Average Value Model of Modular Multilevel Converters With Different Types of Submodules

The large amount of power electronic submodules and semiconductor switching events in the Modular Multilevel Converter (MMC) introduces several challenges for efficient and accurate Electro-Magnetic Transient (EMT) simulation. Research efforts have focused on developing Average Value Models (AVMs) of MMC that enable fast and accurate dynamic simulation of the converter. This paper proposes a universal blocking-module-based AVM, which can simulate the MMC of different submodule types and provide accurate results for the MMC operating in both blocking and de-blocking modes. An analytical approach is included in the model to calculate the semiconductor losses of different submodule types in the MMC. The proposed model is validated against a detailed switching-based model and the state-of-the-art AVMs in a 41-level two-terminal MMC-HVDC system.
Wireless Ground Reaction Force Sensing System Using a Mechanically Decoupled Two-Dimensional Force Sensor

We present the design process of a mechanically decoupled two-dimensional force sensor (M2D) for the implementation of a wearable ground reaction force (GRF) sensing system. The proposed sensor is capable of sensing up to 1000 and <inline-formula><tex-math notation="LaTeX">$ \pm \text{300 N}$</tex-math></inline-formula> in the vertical GRF (vGRF) direction and the anterior–posterior GRF (apGRF) direction, respectively, with accuracies of <inline-formula><tex-math notation="LaTeX">$\text{2.81} \pm \text{0.29}\%$</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">$\text{1.67} \pm \text{0.15}\%$</tex-math></inline-formula>, respectively. With only two reflective optical sensors for each M2D, one for each axis, the mechanical structure of the M2D allows two-dimensional forces to be measured with an axial interference of approximately 1.37% and 2.39% and a repeatability of 0.95% and 1.35% for vGRFs and apGRFs, respectively. A wireless, wearable GRF sensing system was implemented using two M2Ds attached to the outsole of a shoe: one at the heel and the other at the forefoot. The normalized root mean square error value between a conventional stationary force plate and the proposed system for 30 consecutive steps of five subjects was approximately <inline-formula><tex-math notation="LaTeX">$\text{4.93} \pm \text{2.56}\% $</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">$\text{4.22} \pm \text{2.12}\% $</tex-math></inline-formula> for the vGRF and the apGRF, respectively.
Current Ripple Analysis of Three-Phase Vienna Rectifier Considering Inductance Variation of Powder Core Inductor

Three-phase three-level Vienna rectifier using powder core inductors has been widely used for power conversion. Inductor current ripple analysis of rectifier is essential for pulsewidth modulation method optimization, loss estimation, filter inductor design, etc. However, it is hard to analyze the current ripple of Vienna rectifier. Moreover, the inductance of powder core inductor varies with sinusoidal input current, which makes it even more complicated. In this article, a current ripple analysis method for three-phase Vienna rectifier considering the inductance variation of the powder core inductor is presented. The current ripple distribution of Vienna rectifier with constant inductance is studied based on the space vector approach. To determine the current ripple of Vienna rectifier with powder core inductors, an inductor voltage calculation method considering inductance variation is proposed. The compensation voltage is introduced to compensate for the effect of inductance variation on current ripple. Then, the analytical expression of the peak-to-peak current ripple with powder core inductor is derived. In addition, a design method of powder core inductor is proposed based on the analytical expression. At last, the correctness of the analytical result is verified by both simulation and experiment.
Model Predictive Control Tuning by Inverse Matching for a Wave Energy Converter

This paper investigates the application of a method to find the cost function or the weight matrices to be used in model predictive control (MPC) such that the MPC has the same performance as a predesigned linear controller in state-feedback form when constraints are not active. This is potentially useful when a successful linear controller already exists and it is necessary to incorporate the constraint-handling capabilities of MPC. This is the case for a wave energy converter (WEC), where the maximum power transfer law is well-understood. In addition to solutions based on numerical optimization, a simple analytical solution is also derived for cases with a short prediction horizon. These methods are applied for the control of an empirically-based WEC model. The results show that the MPC can be successfully tuned to follow an existing linear control law and to comply with both input and state constraints, such as actuator force and actuator stroke.
Osteoid Osteoma of the Spine is an Important Cause of Back Pain: Two Cases and Review

Two cases are reported and discussed of osteoid osteoma in the spines of two children, presenting as nocturnal low back pain irrelevant to any position or activity. Plain radiographs of the lumbosacral spine, Technetium-99 bone scan and computerized tomography (CT) were used to locate and verify the lesions. Both were then excised by open surgery and confirmed by a post-operative CT scan. A review of all the known and updated modalities of diagnosis and treatment is presented and it is emphasized that this uncommon lesion should be considered in the differential diagnosis of back pain in children.
A Feasibility Study of Additively Manufactured Heat Guides for Enhanced Heat Transfer in Electrical Machines

This article investigates a new heat extraction approach for application to high-specific-output electrical machines. The proposed technique employs thermally conductive heat guides (HGs) to provide supplementary heat evacuation paths for the machine regions, which are particularly susceptible to high power loss. Here, the research focus has been placed on the stator–winding assembly. The HGs investigated in this article rely solely on conductive heat transfer, in contrast to the solutions involving working fluid phase change, e.g., heat pipes. It is intended for the HGs to be an integral part of the stator–winding assembly, for e.g., HGs incorporated in the winding active and/or end region. Such arrangement, however, imposes several design challenges. These are related to the HGs being a source of additional power loss due to the machine's magnetic flux leakage. The objective of this study is to evaluate a concept of HGs, which are immune to the external magnetic field with good heat transfer capability. To facilitate that, a combination of detailed multiphysic design optimization and modern additive manufacturing (i.e., selective laser melting method) has been employed here. The theoretical analysis has been supplemented with an experimental work. A number of stator–winding hardware exemplars (motorettes) incorporating alternative HG designs have been fabricated and tested. This article provides a new set of experimental data in support of the authors’ initial work on HGs’ thermal behavior. The new research findings show that the optimized HGs allow for up to 85% improvement in dissipative heat transfer from the winding body and insignificant additional power loss, for the analyzed stator–winding assembly.
Precision Motion Control of a Servomotor-Pump Direct-Drive Electrohydraulic System With a Nonlinear Pump Flow Mapping

Pump control hydraulic systems can achieve high efficiency by the advantages of no throttling loss and high power-to-volume ratio. However, low tracking accuracy and slow frequency response are main drawbacks for the applications of pump control hydraulic systems, because of the existing high-order dynamics, uncertainties, and highly nonlinear dynamics. Recently, the advent of servomotor-pump direct-drive electrohydraulic systems shows a good prospect for this issue, and the design of the control algorithm is the key to achieve high motion accuracy. In this article, to achieve precision motion control, an adaptive robust control with a backstepping design is proposed for an electrohydraulic system, where the cylinder actuator is direct-driven by a servomotor pump. Considering the high-order dynamics and nonlinearities of hydraulic systems, the controller is processed in two steps: position tracking step and pressure step. Besides, the pump flow deviation under low speed is another important limitation for good control performance. Thus, a nonlinear pump flow rate mapping is proposed by practical fitting and used into the controller design by the proper nonlinearity compensation of the desired pump flow. Comparative experiment results show that the proposed control strategy achieves high motion control performances in spite of the nonlinearities and uncertainties.
An Effective Reversible Data-Hiding in Encrypted Images Using Memory Cellular Automata

Abstract This article attempts to propose an effective reversible data-hiding in encrypted images using memory cellular automata. The image content owner encrypts the original image using a Paillier homomorphic encryption algorithm with an encryption key and uploads the encrypted image into the cloud server. Then, the data hider embeds additional data into the encrypted image with an embedding key. Whenever the user gets both keys, the original image can be recovered without any errors. Compared to existing reversible data-hiding in encrypted image methods, the proposed method has better embedding rates, embedding payloads, and high-security performance.
A Decentralized Control for Cascaded Inverters in Grid-Connected Applications

In this letter, a decentralized control for cascaded inverters is introduced, in which one inverter is controlled as a current source and the others are controlled as voltage sources. The power sharing and synchronization of the inverters are realized without high-bandwidth communication. Meanwhile, it is robust against the voltage sag\swell and frequency deviation of grid. Finally, the feasibility of the proposed method is verified by simulation and experimental results.
Thermal Modeling and Analysis of Active and End Windings of Enclosed Permanent-Magnet Synchronous In-Wheel Motor Based on Multi-Block Method

This paper presents an accurate modeling method to investigate the thermal performance of the windings under steady state. The model considers the heat conduction of active windings and heat convection of end windings. To verify the validity of this model, a 20/24 poles/slots permanent magnet (PM) in-wheel motor is taken as an example. Firstly, the temperature distribution of the active windings in the slot is calculated by a multi-block 2-D temperature field model, which is verified by the model built according to the reality. The numerical results of blocks model agree well with those of the real model. Secondly, a 3-D temperature field model with the end windings is built on the 2-D blocks model. Furthermore, to include the air inside the motor, computational fluid dynamics (CFD) has been utilized, and the numerical results are experimentally verified. Finally, the distribution of the heat transfer coefficient (HTC) of the end windings and the influence of rotor speed on the HTC are investigated. These HTCs acquired from CFD results and empirical formulas are compared and analyzed carefully.
Impedance Modeling and Analysis of MMC-HVDC for Offshore Wind Farm Integration

The offshore ac side impedance model of the modular multilevel converter (MMC) based high voltage direct current (HVdc) system is essential for analyzing the interaction stability between MMC-HVdc and the offshore wind power plants. This paper develops the offshore ac side impedance model of an MMC-HVdc system for wind power integration taking the effects of offshore station, dc cable and onshore station into consideration. The dc impedance model of the onshore station is first derived which includes the effects of dual closed loop dc bus voltage control and circulating current control. Then, the dc impedance of the onshore station and dc cable impedance are used to derive the ac side impedance of the offshore station under open loop control. In addition, the influence of the dual closed loop based ac bus voltage and frequency (VF) control on the offshore ac impedance is analytically derived. As a result, the proposed model can be used to reveal the coupling between offshore offshore ac system and dc system as well as to investigate the influence of the dc system and VF controller in the offshore ac impedance of the MMC-HVdc system. Furthermore, the proposed model overcomes the deficiencies in harmonic resonance analysis of MMC-HVdc based offshore wind power integration system. The results of the simulation in PSCAD/EMTDC validate the proposed models and analyses.
An Assistant-Mover-Based Position Estimation Method for Planar Switched Reluctance Motors

An accurate mover position is important for a planar switched reluctance motor (PSRM) to achieve precision positioning; however, position sensors are susceptible to the influence from harsh conditions and are relatively expensive. In this article, an assistant-mover-based position estimation method is proposed to increase the reliability and reduce the cost of a PSRM system. The method is based on a mapping relationship between the flux density and position of the assistant mover. First, the configuration of the assistant movers is presented. Then, an analytical model of the flux density of the assistant mover is developed by using an equivalent magnetic circuit method. Based on the analytical model, the parameters of the assistant mover are determined. According to the flux density characteristics, a position estimation algorithm with the advantages of not requiring previous experimental data, simple computation, and small memory consumption is developed. Moreover, considering the deviation in the characteristics of each assistant mover, a compensation strategy is proposed to obtain better position estimation accuracy. Finally, the proposed method is implemented with the PSRM system. The effectiveness of the proposed position estimation method is verified experimentally.
Improving TCP Performance in Vehicle-To-Grid (V2G) Communication

On a connected car, the performance of Internet access will significantly affect the user experience. For electric cars that use vehicle-to-grid (V2G) communication to interact with the Internet during charging, the charge cable quality poses a challenge to the V2G communication. Specifically, the performance of Transmission Control Protocol (TCP), the transport protocol that most Internet applications use, may suffer due to the high noise and consequent errors that the charge cable presents. Currently, TCP NewReno is the TCP implementation that ISO 15118 standard stipulates for the V2G communication. However, its congestion control algorithm has been designed for the general Internet environment where congestion, not link errors, account for most of packet losses. Indeed, we confirm that the throughput of TCP NewReno rapidly degrades as the error rate increases on the charge cable. Specifically, we show that other TCP variants such as TCP Illinois far exceeds TCP NewReno in both lossy and non-lossy link environments. Finally, we propose how to configure TCP NewReno parameters to make it achieve the throughput comparable to other TCP variants on V2G communication environments, regardless of the link quality presented by the charging cable.
Persistent AUV Operations Using a Robust Reactive Mission and Path Planning (RRMPP) Architecture.

Providing a higher level of decision autonomy and accompanying prompt changes of an uncertain environment is a true challenge of AUVs autonomous operations. The proceeding approach introduces a robust reactive structure that accommodates an AUV's mission planning, task-time management in a top level and incorporates environmental changes by a synchronic motion planning in a lower level. The proposed architecture is developed in a hierarchal modular format and a bunch of evolutionary algorithms are employed by each module to investigate the efficiency and robustness of the structure in different mission scenarios while water current data, uncertain static-mobile/motile obstacles, and vehicles Kino-dynamic constraints are taken into account. The motion planner is facilitated with online re-planning capability to refine the vehicle's trajectory based on local variations of the environment. A small computational load is devoted for re-planning procedure since the upper layer mission planner renders an efficient overview of the operation area that AUV should fly thru. Numerical simulations are carried out to investigate robustness and performance of the architecture in different situations of a real-world underwater environment. Analysis of the simulation results claims the remarkable capability of the proposed model in accurate mission task-time-threat management while guarantying a secure deployment during the mission.
A Dynamic Programmable Network for Large-Scale Scientific Data Transfer Using AmoebaNet

Large scientific experimental facilities currently are generating a tremendous amount of data. In recent years, the significant growth of scientific data analysis has been observed across scientific research centers. Scientific experimental facilities are producing an unprecedented amount of data and facing new challenges to transfer the large data sets across multi continents. In particular, these days the data transfer is playing an important role in new scientific discoveries. The performance of distributed scientific environment is highly dependent on high-performance, adaptive, and robust network service infrastructures. To support large scale data transfer for extreme-scale distributed science, there is the need of high performance, scalable, end-to-end, and programmable networks that enable scientific applications to use the networks efficiently. We worked on the AmoebaNet solution to address the problems of a dynamic programmable network for bulk data transfer in extreme-scale distributed science environments. A major goal of the AmoebaNet project is to apply software-defined networking (SDN) technology to provide “Application-aware” network to facilitate bulk data transfer. We have prototyped AmoebaNet’s SDN-enabled network service that allows application to dynamically program the networks at run-time for bulk data transfers. In this paper, we evaluated AmoebaNet solution with real world test cases and shown that how it efficiently and dynamically can use the networks for bulk data transfer in large-scale scientific environments.
Competitor Intelligence and Product Innovation: The Role of Open-Mindedness and Interfunctional Coordination

Drawing on the central theme of open innovation and the inbound flow of knowledge for improving a firm's innovation performance, this research investigates the application of external knowledge (i.e., competitor intelligence) in product innovation through the mediators of interfunctional coordination and open-mindness. We examine the joint moderating effect of environmental uncertainty on results obtained from survey data involving 284 executives from Chinese small- and medium-sized enterprises (SMEs) within the information technology. Our results reveal that competitor intelligence has a positive and direct effect on product innovation and relationships can be further strengthened by interfunctional coordination and open-mindedness. In testing their interaction with dynamic external environments, we found that the level of environmental uncertainty interacts positively with open-mindedness, but negatively with the effect of interfunctional coordination on product innovation. We conclude that by building openly innovative and knowledge sharing culture, SME managers can improve their product innovation performance by obtaining and processing external knowledge relating to competitors. This article contributes to the open innovation literature, advancing understanding of the inflow of external knowledge for innovative output and, more importantly, sheds light on the research of open innovation practices in SMEs from emerging economies.
Radio Propagation Calculation: A Technique Using 3D Fresnel Zones for Decimeter Radio Waves on Lidar Data

This article discusses the Fresnel radio tool (FRT) model for radio-coverage prediction based on the Fresnel-zone calculation. The 3D Fresnel zones are calculated from the transmitter (Tx) source to each cell on a raster digital map. For numerical calculation purposes, Fresnel zones are cross sectioned to a finite number of fragments. The attenuation and phase shift of each segment can be adjusted according to the obstacle type. At the target receiver (Rx) point, contributions from each fragment, represented by complex numbers, are summed and converted to a signal strength.
Synergy Effects in Electromagnetic Properties of Phosphate Ceramics with Silicon Carbide Whiskers and Carbon Nanotubes

Hybrid composite materials based on an aluminium phosphate matrix with silicon carbide whiskers and multi-walled carbon nanotubes were studied in a wide frequency range (20 Hz to 36 GHz). It was demonstrated, that the addition of the silicon carbide whiskers enhances the dielectric permittivity and conductivity. This was explained by the difference in tunnelling parameters. Hybrid ceramics with nanotubes and whiskers also exhibits substantially improved electromagnetic shielding properties. The hybrid ceramics with 10 wt. % silicon carbide whiskers and a 1 mm thick 1.5 wt. % carbon nanotube layer, show higher than 50% absorption of electromagnetic radiation.
State of Charge Estimation Algorithm for Unmanned Aerial Vehicle Power-Type Lithium Battery Packs Based on the Extended Kalman Filter

The lack of endurance is an important reason restricting further development of unmanned aerial vehicles (UAVs). Accurately estimating the state of charge (SOC) of the Li-Po battery can maximize the battery energy utilization and improve the endurance of UAVs. In this paper, the main current methods for estimating the SOC of vehicles were explored and discussed to unveil their advantages and disadvantages. In addition, the extended Kalman filter algorithm based on an equivalent circuit model was used to estimate SOC of power-type Li-Po batteries at different temperatures. The result showed that the closed-loop control method can effectively improve the battery life of small-sized electric UAVs.
An Integrated Biological Analysis and Flow Rate Sensing for the Real-Time Detection of Carcinogen in Water Based on Co2+-Doped Optical Fibers

The multi-parameter measurement has significant meaning for biosensor to enhance their practical sensing performance. For the biological detection, simultaneous measurement of biological molecule and flow rate could improve the accuracy and sensitivity of sensors significantly. In this paper, an integrated biological analysis and flow rate sensing based on Co2+ doped tilted fiber Bragg gratings has been proposed and experimentally demonstrated for real-time the detection of the Benzo[a]pyrene molecules. A tilted fiber Bragg grating with a tilted angle of 8° was inscribed into a Co2+ doped fiber. The flow rate and Benzo[a]pyrene molecules can be measured simultaneously by interrogating the resonance wavelength of core mode and wavelength interval between the core mode and cladding mode according to the heat exchange and evanescent field of the cladding mode, respectively. Experimental results show that the real-time measurement sensitivities of 12 pm/pM and −0.13 nm/( $\mu \text{L}$ /s) for the Benzo[a]pyrene detection and flow rate were achieved, respectively. Thus the technique appears to have potential applications in chemistry, medicine, and biology.