Miracle-dz/UniFAR-FTUs huggingface dataset:
A Quadruple Active Bridge Converter for the Storage Integration on the More Electric Aircraft

The More Electric Aircraft concepts aims at increasing the penetration of electric systems on aircrafts. In this framework, the electrical power distribution system (EPDS) is of high importance. In order to improve the utilization of the generators and face the peak power demand without disconnecting the loads, different technologies of storage are employed. This paper proposes the use of a quadruple active bridge converter, already employed in other fields, to interface a fuel cell, a battery, and a supercapacitor bank to the dc bus of the EPDS. This objective can be achieved by employing multiple dc/dc converters, which allow an individual control of the energy sources and a good efficiency. Obtaining the same power control and efficiency with a multiport power converter constitutes a challenge that is worth taking to reduce cost, volume, and weight and increase the system reliability. A novel control based on proportional integral (PI) controllers in conjunction with a decoupling system and current feedforward allow shaping the power request to each port. This, however, leads to an asymmetrical loading of each port, which could decrease the efficiency. A laboratory prototype is used to confirm that this asymmetrical kind of operation, where each port processes a different amount of power, does not imply a marked reduction of efficiency.
Precrop Functional Group Identity Affects Yield of Winter Barley but Less so High Carbon Amendments in a Mesocosm Experiment

Nitrate leaching is a pressing environmental problem in intensive agriculture. Especially after the crop harvest, leaching risk is greatest due to decomposing plant residues, and low plant nutrient uptake and evapotranspiration. The specific crop also matters: grain legumes and canola commonly result in more leftover N than the following winter crop can take up before spring. Addition of a high carbon amendment (HCA) could potentially immobilize N after harvest. We set up a 2-year mesocosm experiment to test the effects of N fertilization (40 or 160 kg N/ha), HCA addition (no HCA, wheat straw, or sawdust), and precrop plant functional group identity on winter barley yield and soil C/N ratio. Four spring precrops were sown before winter barley (white lupine, faba bean, spring canola, spring barley), which were selected based on a functional group approach (colonization by arbuscular mycorrhizal fungi [AMF] and/or N2-fixing bacteria). We also measured a subset of faba bean and spring barley for leaching over winter after harvest. As expected, N fertilization had the largest effect on winter barley yield, but precrop functional identity also significantly affected the outcome. The non-AMF precrops white lupine and canola had on average a positive effect on yield compared to the AMF precrops spring barley and faba bean under high N (23% increase). Under low N, we found only a small precrop effect. Sawdust significantly reduced the yield compared to the control or wheat straw under either N level. HCAs reduced nitrate leaching over winter, but only when faba bean was sown as a precrop. In our setup, short-term immobilization of N by HCA addition after harvest seems difficult to achieve. However, other effects such as an increase in SOM or nutrient retention could play a positive role in the long term. Contrary to the commonly found positive effect of AMF colonization, winter barley showed a greater yield when it followed a non-AMF precrop under high fertilization. This could be due to shifts of the agricultural AMF community toward parasitism.
An Ultralow Quiescent Current Power Management System With Maximum Power Point Tracking (MPPT) for Batteryless Wireless Sensor Applications

This paper presents a chip-scale ultralow quiescent current power management system that interfaces with electromechanical energy harvester for enabling self-powering, batteryless wireless sensors. A piezoelectric transducer scavenges and transforms mechanical vibration energy into electricity in ac form, which is then converted into dc power by a full bridge rectifier and collected into a small filter capacitor. A buck–boost converter, as an impedance matching converter to achieve maximum power point tracking, further transfers the energy into a supercapacitor, from which a low-dropout (LDO) regulator powers an on-chip CMOS sensor with clean power supply. Additionally, the energy stored in the supercapacitor can be used to drive a radio frequency transmitter. These components form a complete wireless sensor node, applicable for the Internet of Things sensor networks. The chip is fabricated by using a standard 0.5 μm CMOS process. From measurements we have verified all the key merits of this design: first, a high voltage converting efficiency (up to 97.1%) of the rectifier; second, a minimum of 102 s charging time to charge a 1 mF supercapacitor from 0 to 3.3 V of the buck–boost converter with impedance matching method; and third, a 10 nA to 100 μA load current range and at least 85° phase margin LDO regulator with ultralow quiescent bias current as low as 750 pA.
Human infants can generate vergence responses to retinal disparity by 5 to 10 weeks of age

Vergence is defined as a binocular eye movement during which the two eyes move in opposite directions to align to a target in depth. In adults, fine vergence control is driven primarily by interocular retinal image disparity. Although infants have not typically been shown to respond to disparity until 3 to 5 months postpartum, they have been shown to align their eyes from hours after birth. It remains unclear what drives these responses in young infants. In this experiment, 5- to 10-week-old human infants were presented with a dynamic random noise stimulus oscillating in disparity at 0.1 Hz over an amplitude of 2° for 30 s. Fourier transforms of the horizontal eye movements revealed significant disparity-driven responses at the frequency of the stimulus in over half of the tested infants. Because the stimulus updated dynamically, this experiment precluded the possibility of independent monocular fixations to a sustained target. These data demonstrate cortical binocular function in humans by five weeks, the youngest age tested here, which is as much as two months younger than previously believed.
Novel Filtering 180° Hybrid Coupler and Its Application to  $2 \times4$  Filtering Butler Matrix

In this paper, a novel filtering 180° hybrid coupler is proposed and used to design a <inline-formula> <tex-math notation="LaTeX">$2 \times 4$ </tex-math></inline-formula> filtering Butler matrix. The filtering 180° hybrid coupler can provide power division and phase shift together with a second-order bandpass transfer function, and is based only on coupled resonators. The <inline-formula> <tex-math notation="LaTeX">$2 \times 4$ </tex-math></inline-formula> filtering Butler matrix is easily realized by utilizing several hybrid couplers. The analytical synthesis procedures for the hybrid coupler and Butler matrix are presented in this paper. Finally, broadside and end-fire arrays are realized by using the Butler matrix. To illustrate the concept experimentally, a filtering 180° microstrip hybrid coupler and a <inline-formula> <tex-math notation="LaTeX">$2 \times 4$ </tex-math></inline-formula> filtering microstrip Butler matrix are designed, fabricated, and measured. Simulation and measured results are found to be in good agreement with each other.
Inserting polarization processes in a fluid charge transport model: Improvements and difficulties

Understanding the space charge behaviour in solid organic insulations under thermo-electrical stress is of particular interest as charge dynamics is closely related to electric field distortion, charge accumulation and at last to materials ageing. Many polymers used as electrical insulators are polar materials, and have a non-linear behaviour as regards conduction processes. Hence, the underlying physics is not easily accessible and understandable. A charge transport model coupled with relaxation functions has been developed recently. In this paper, a comparison between the experimental measurements and the simulation results extracted from the coupled models is proposed, for two different materials: a polar material (PEN) and a weakly polar material (LDPE). From these results, we discuss the issues related to the prediction of the thermo-electrical behaviour of solid organic insulating materials, when the difficulty arises not only from the experimental observation (i.e. separating polarisation from transport processes), but also from the mathematical treatment required for modelling.
Asymmetric Coil Structures for Highly Efficient Wireless Power Transfer Systems

A transmitter coil (TX-coil) as well as a receiver coil (RX-coil) has been designed at 6.78 MHz for magnetic resonant wireless power transfer systems not only to have high efficiency at medium distances, which is comparable to the coil dimensions, but also to provide stable efficiency over the position variation of the RX-coil. For mobile devices, the coils should be compact and have low profile and asymmetric, meaning that TX- and RX-coils have different dimensions. In this paper, TX-coil is designed by adding a small coil in series to achieve high quality factor (Q-factor) as well as relatively uniform magnetic field distribution. On the other hand, the scaling factor is introduced for wire width to design RX-coil with higher Q-factor. As a result, the proposed asymmetric coils reveal improved efficiency and degree of freedom in terms of position variation. This has been verified by measuring the system performance, including a power amplifier, full-wave rectifier, regulator, and load. The proposed TX-coil has size of <inline-formula> <tex-math notation="LaTeX">$200 \times 200 \times 1$ </tex-math></inline-formula> mm<sup>3</sup>, while the size of the RX-coil is <inline-formula> <tex-math notation="LaTeX">$100\times 100\times0.4$ </tex-math></inline-formula> mm<sup>3</sup>. The power transfer efficiency is 96% and 39% at the transmission distances of 50 and 300 mm, respectively.
A back biasing voltage generator for 28nm UTBB-FDSOI RVT CMOS digital circuits

This paper presents a Back-Biasing regulation module developed for the next-generation of 28nm UTBB FDSOI (Ultra-Thin Box and Body Fully Depleted Silicon On Insulator) IOT microcontroller products. The module enables both Reverse Back Biasing (RBB) and Forward Back Biasing (FBB) of a standard digital logic region with programmable voltage levels. Main design requirements and regulator load characteristics are analyzed. A description of the load model is also included. Silicon results from a circuit implementation included in i.MX7ULP™ low-power microcontroller are presented. The circuit occupies an area of 0.2mm2 with negligible power consumption compared to the total system.
MultiDroid: An Energy Optimization Technique for Multi-Window Operations on OLED Smartphones

The inbuilt multi-window feature released with Android Nougat has enabled simultaneous working and visualization of multiple applications on mobile display screen. However, multi-window operations result in unnecessary energy drain due to increased multitasking, CPU load, and multithread processing. Considering linear dependence between power consumed and the displayed colors, we present the design and realization of MultiDroid, a novel display power reduction technique during multi-window operations for the OLED screens. MultiDroid employs dynamic local dimming based on the context switching between the application pairs displayed on the screen. The display optimization works based on the user interaction with the mobile screen, where dynamic changes on the display screens are implemented for the non-critical application window. MultiDroid architecture is validated through power modeling and correctness verification. Furthermore, a survey on multi-window usage has been conducted reflecting the application usage pattern. The performance of MultiDroid is evaluated on preferred application pairs on multi-window framework obtained from the survey. Modeling and comparative analysis of the energy profiles for the devised test cases on optimized and default multi-window screens reflect around 10% to 25% reduction in the overall device power consumption per hour with a negligible performance degradation. After experimental validation, we present user acceptance and feasibility of MultiDroid based on the feedback from 50 participants.
Microresonator-on-Membrane for Real-Time Mass Sensing in Liquid Phase

Microresonator-on-membrane (MRoM) is presented in this article as a new approach to address the performance deterioration of microscale resonators in contact with a liquid media. An MRoM is composed of a rectangular piezoelectric-on-substrate resonator formed on top of an isolating membrane, which can operate in its length and width extensional (LE and WE) resonance modes. In the proposed scheme, the solution under a test is added into a microcavity on the back side of the MRoM chip. In this manner, the contact surface of the resonator to liquid is minimized to reduce mechanical losses caused by viscous damping, leading to a higher resonator quality factor ( Q). Simultaneously, isolation caused by the membrane eliminates electrical interference of ionic solutions on a resonator performance. Despite enabling such advantages, the membrane underneath the resonator causes further anchoring losses, which reduces the Qs of MRoMs operating in air. To minimize such losses, in-plane primary and secondary circular acoustic reflectors are located around the resonator leading to higher Qs. Consequently, the MRoMs with secondary reflectors exhibit the Qs as high as 3500 for operation at both LE and WE resonance modes of 39 and 83MHz, respectively, when operating in air, showing adequate suppression of anchoring loss caused by the presence of the membrane. Also, maximum liquid phase Q s up to 410 are achieved for the MRoMs, which operate in the WE mode. As mass sensors, the MRoMs demonstrate mass sensitivity of 12 Hz.cm2ng while operating at the same mode.
Series-Connected Partial-Power Converters Applied to PV Systems: A Design Approach Based on Step-Up/Down Voltage Regulation Range

This paper proposes a novel approach to reduce the power processed by series-connected partial-power converters (S-PPC) applied to string/multistring level maximum power point tracking photovoltaic systems. A design procedure based on the definition of the voltage regulation range is presented. It introduces an additional degree of freedom that allows a proper design of the converter in order to reduce not only the active power but also the nonactive power, reducing losses and increasing power density. By means of the proposed approach, it is also demonstrated that by replacing the conventional step-up partial-power converter by a step-up/down partial-power converter, the active and nonactive power can be further reduced, allowing to better explore the benefits of the partial-power concept. In order to validate the proposed approach, two 750-W prototypes of full-bridge S-PPC and full-bridge/push–pull S-PPC were implemented and experimentally evaluated. The step-up/down prototype presented a reduction of 46.9% in nonactive power and 23.4% of its volume, resulting in a higher efficiency and power density in comparison to the voltage step-up prototype counterpart.
Insulation property analysis of cross-linked polyethylene based on density functional theory

In recent years, molecular simulation technology, as the third mothed besides experiment and analysis, has been widely used in various fields. In the field of high voltage, molecular simulation is widely used in oilpaper and polymer insulation characteristics analysis, pyrolysis analysis and so on. In this paper, in order to clarify the electric aging mechanism of cross-linked polyethylene(XLPE), a simple XLPE molecular model is established with the ORCA package and the basic sets 3–21G, 6–31G and 6–311G(d, p) are utilized to optimize and get the most stable structure. We have chosen the band length, band gap and charge transfer within the molecule to characterize the XLPE molecule's status under electric field. The results show that the structural parameters and energy of the molecule present linear changes with electric strength. Especially, the band gap presents a downward trend, which means the insulation property of the material has decreased with the electric strength increases. These phenomena reveal the aging mechanism of XLPE molecule under electric field conditions, which is of great significance to the status evaluation of XLPE cable.
An Application of Decentralized Estimation in a Fault Detection Problem

This paper presents a design of a decentralized fault detection and isolation (FDI) filter by means of an overlapping decentralized estimation algorithm based on a consensus strategy. An efficient solution to the FDI problem can be obtained by an adequate system decomposition into overlapping subsystems and the construction of local FDI estimators aimed at achieving the desired performance. The general aspects and properties of a consensus based estimator are described in the first part of the paper. An applicability of such an estimator to an FDI problem in a large scale system is discussed next. Namely, a case study related to the detection of fire dissymmetry in a thermal power plant boiler is presented, including the process description and identification procedure, comparison between the results obtained by local and decentralized estimators and conclusions concerning their validity.
Leveraging Information Asymmetry to Transform Android Apps into Self-Defending Code Against Repackaging Attacks

By simply adding malicious code or advertisements in legitimate smartphone apps, attackers could benefit a lot from repackaging. The existing license protection mechanisms can be easily subverted by repackaged apps. A major defense is to detect. However, detection requires finding at least two “similar” apps simultaneously. We propose a self-defending approach: let a repackaged app automatically expose itself. However, it is very challenging to achieve this goal. If developers and smartphones/users do not share any secret, attackers’ app repackaging studio would be able to do whatever legitimate smartphones/users are able to do. We find that there exists a unique information asymmetry between developers and attackers. Leveraging this asymmetry, our new self-defending code (SDC) approach encrypts parts of the app code at compile time and dynamically decrypts the ciphertext code at run-time. Different from previous work, the key is derived from both the information asymmetry and the app's checksum. Once the app is repackaged, the changed checksum will let the app run abnormally, further exposing the repackaging. The information asymmetry protects the key from being attacked. We build a smartphone anti-repackaging system prototype. To the best of our knowledge, this is the first work that lets repackaged apps automatically malfunction while having none effect on a benign app's function.
Destination-specific maximally redundant trees: Design, performance comparison, and applications

Resilient networks react to a failure by reconfiguring routing tables in a network-wide manner and utilizing fast reroute (FRR) in the meanwhile. FRR uses pre-computed backup paths to avoid the failure locally. The existing FRR approaches for IP networks and Software-Defined Networking (SDN) differ in regard to computational complexity, backup path length, additional forwarding state and required capacities. Maximally Redundant Trees (MRTs) are standardized by the IETF and are already available for IP and MPLS networks. In this paper, we propose destination-specific MRTs (dMRTs), an improved variant of MRTs, for protection of IP networks. This mechanism reduces the generated path lengths but increases the computational complexity of the MRT algorithm. We analyze and compare our proposal with simple MRTs and MPLS FRR. We show on a large and publicly available network data base that dMRTs provide significant shorter backup paths compared to simple MRTs and require less forwarding state and network capacities than MPLS FRR. Adapting an existing FRR mechanism for IP networks to SDN enables its deployment in hybrid-SDN networks. Thus, we outline implementation options of dMRTs in IP and MPLS networks and (d)MRTs in SDN. Finally, we discuss the computational overhead of our proposal in the context of (decentralized) IP networks and (centralized) SDNs.
Voice Activity Detection Using an Adaptive Context Attention Model

Voice activity detection (VAD) classifies incoming signal segments into speech or background noise; its performance is crucial in various speech-related applications. Although speech-signal context is a relevant VAD asset, its usefulness varies in unpredictable noise environments. Therefore, its usage should be adaptively adjustable to the noise type. This letter improves the use of context information by using an adaptive context attention model (ACAM) with a novel training strategy for effective attention, which weights the most crucial parts of the context for proper classification. Experiments in real-world scenarios demonstrate that the proposed ACAM-based VAD outperforms the other baseline VAD methods.
Enabling Phased Array Signal Processing for Mobile WiFi Devices

Modern mobile devices are equipped with multiple antennas, which brings various wireless sensing applications such as accurate localization, contactless human detection, and wireless human-device interaction. A key enabler for these applications is phased array signal processing, especially Angle of Arrival (AoA) estimation. However, accurate AoA estimation on commodity devices is non-trivial due to limited number of antennas and uncertain phase offsets. Previous works either rely on elaborate calibration or involve contrived human interactions. In this paper, we aim to enable practical AoA measurements on commodity off-the-shelf (COTS) mobile devices. The key insight is to involve users’ natural rotation to formulate a virtual spatial-temporal antenna array and conduce a relative incident signal of measurements at two orientations. Then by taking the differential phase, it is feasible to remove the phase offsets and derive the accurate AoA of the equivalent incoming signal, while the rotation angle can also be captured by built-in inertial sensors. On this basis, we propose Differential MUSIC (<italic>D-MUSIC</italic>), a relative form of the standard MUSIC algorithm that eliminates the unknown phase offsets and achieves accurate AoA estimation on COTS mobile devices with only one rotation. We further extend <italic>D-MUSIC</italic> to 3-D space, integrate extra measurements during rotations for higher estimation accuracy, and fortify it in multipath-rich scenarios. We prototype <italic>D-MUSIC</italic> on commodity WiFi infrastructure and evaluate it in typical indoor environments. Experimental results demonstrate a superior performance with average AoA estimation errors of 13<inline-formula> <tex-math notation="LaTeX">${}^{\circ}$</tex-math><alternatives><inline-graphic xlink:href="qian-ieq1-2778155.gif"/> </alternatives></inline-formula> with only three measurements and 5<inline-formula><tex-math notation="LaTeX"> ${}^{\circ}$</tex-math><alternatives><inline-graphic xlink:href="qian-ieq2-2778155.gif"/></alternatives> </inline-formula> with at most 10 measurements. Requiring no modifications or calibration, <italic>D-MUSIC</italic> is envisioned as a promising scheme for practical AoA estimation on COTS mobile devices.