Miracle-dz/UniFAR-FTUs huggingface dataset:
Boosting Qs of AlN Resonators by Redefining Acoustic Boundaries

This paper reports on a quality factor ($Q$)-boosting technique for aluminum nitride (AlN) Lamb wave resonators by lithographically defining their acoustic boundaries. The technique has been demonstrated to enhance resonator $Q$ from 980 to 3000 without compromising the electromechanical coupling $({k_{\mathrm{t}}}^{2}=1.75\%)$, consequently resulting in a high figure of merit of 52.25 ($\text{FoM}={k_{\mathrm{t}}}^{2}\cdot Q$). Our approach derives from our quantitative analysis of the reflection coefficient at the acoustic boundaries of a conventional Lamb wave AlN resonator, which suggests inadequate energy confinement from a reflection coefficient of only 0.47. A two-prong approach, which involves first defining the release regions lithographically and then adding a Pt layer regionally over the anchors, is adopted to create a more significant impedance mismatch at the acoustic boundaries and reduce energy leakage to the surrounding.
Bipartite Consensus of Time-varying Multi-agent Systems with Signed Edge Dynamics

In this work, the bipartite consensus problem for a time-varying multi-agent system with signed edge dynamics is investigated. The interaction between agents can be modeled by a time-varying signed digraph, in which the edge weights can be any real numbers and can be denoted by some functions. The primary objective is to seek a new rule that can transform a time-varying signed node digraph to a time-varying signed edge digraph. A distributed consensus protocol is designed for the time-varying multi-agent system with signed edge dynamics. A simulation example is provided to illustrate the effectiveness of the proposed protocol.
Development of Leaping/Flipping Behaviors in a Quadruped Robot with Passive Compliant Legs

We report the development of a model-based leaping/flipping quadruped robot. The planar model contains a planar rigid body and two compliant legs to investigate how forces are transmitted from the ground to the body through the foreleg and the hindleg and the resultant forces and moment on the body. The spring-loaded compliant leg with rolling contact was chosen for analysis, while the widely-used spring-loaded compliant leg with point contact was also developed for comparison purpose. The model’s equations of motion (EOM) were derived for four modes: double stance, hindleg stance, foreleg stance, and flight. Moreover, the factors of initial pitch angle and relative actuation timing that affect whether the motion is a forward leap or a flip were investigated. The results indicate that different factors dominate different indices of the leaping/flipping motion—body pitch variation is mainly determined by the initial pitch angle; lift-off angle is determined by the delay of the foreleg; and stance time is affected by the delay of the hindleg. The same parameters were applied and evaluated in a robot that exhibited the leaping and flipping behaviors predicted by the model.
Multiplexing Avionics and additional flows on a QoS-aware AFDX network

AFDX is the standard switched Ethernet solution for the transmission of avionics flows. Today’s AFDX deployments in commercial aircrafts are lightly loaded to ensure the determinism of control and command operations. Manufacturers envision to take advantage of the remaining AFDX bandwidth to transmit additional non avionics flows (video, audio, service). These flows must not compromise the in-time transmission of avionics ones: constraints on jitter at source end system and end-to-end latency have to be insured for each avionics flow. In this paper, we investigate the scheduling of avionics and additional flows, mainly at the end system level. We show that an event-triggered strategy is better than a time-triggered one for additional flows at source level, but it might compromise the jitter constraint of avionics flows and increase the end-to-end latency of additional ones. We consider two time-triggered scheduling strategies, i.e. an optimal one and a simpler one based on a heuristic. We show that the later one performs nearly as well as the former one and that, for both of them, the difference with an event-triggered strategy at source level is limited and can be statically bounded.
Enhancing Battery Pack Capacity Utilization in Electric Vehicle Fleets via SoC-Preconditioning

Modern public transport solutions based on autonomous electric vehicles are on the rise. Public transportation as a service on demand is becoming a reality. Therefore, vehicles suitable for these kinds of applications need to be developed. One critical factor for such vehicles is a short turnaround time at the charging spot. Maximizing the utilization of a given battery pack capacity and minimizing the time spent charging are therefore of central importance. In this paper, we propose a novel preconditioning algorithm to minimize the time an EV is connected to the charging station. Our proposed approach uses existing Active Cell Balancing (ACB) hardware of the battery pack to precondition the State of Charge (SoC) of cells such that all cells reach the top SoC threshold at the same time without requiring an additional balancing phase during charging. This is done by considering the individual cells' charging rate to precondition them for achieving an equal time to full charge. Applying the same approach for discharging, we also extend the driving range of an EV, which otherwise is limited by the cell with the lowest SoC in the pack. Case studies show that our proposed preconditioning algorithm increases the usable energy of the battery pack by up to 3% compared to conventional balancing algorithms all while effectively halving the time connected to a charging station, all without requiring any additional hardware components.
A pedagogical platform for metaheuristic optimization

Regardless the engineering scientific areas wherein one develops research and training, it is often necessary not just to find a solution for a specific problem, but to find its optimal solution according to a set of predefined objectives and constraints. Therefore the introduction and familiarization to optimization techniques is an important topic that may be explored as soon as essential engineering concepts and behavioral characteristics are apprehended. Bearing this perspective in mind, this work presents a platform with pedagogical purposes for the optimization process learning in the context of metaheuristic techniques. This paper presents some of the platform functionalities, considering a very recent technique, the stochastic fractal search.
Segmentation of Depth Images into Objects Based on Polyhedral Shape Class Model

A novel approach for object detection in depth images based on a polyhedral shape class model is proposed. The proposed segmentation algorithm decides whether a subset of image points represents a physical object on the scene or not by comparing its 3D shape to several shape classes. The algorithm is designed for cluttered scenes with simple convex or hollow convex objects. The proposed algorithm is trained using a set of 3D models of objects belonging to several shape classes, which are expected to appear in the scene. The presented method is experimentally evaluated using a publicly available benchmark dataset and compared to three state-of-the art approaches.
MIM Junction Under A Source Of Light Distributed

Metal-insulator-metal junctions are tunneling diodes able to operate at very high frequencies, arriving at the optical ones. The quantum tunneling is a stochastic event that depends very much on the insulator thickness. The insulator thickness is under the diffraction limit of the light that illuminates the diode. Particularly, in the mid-infrared, the insulator thickness is several orders of magnitude under the diffraction limit, and the electromagnetic field cannot penetrate into the structure. In all papers reviewed, the wave which illuminates the diode, inside the junction, is transformed in an evanescent one. The only way in which the electromagnetic radiation can be introduced into the structure is through a traveling wave of surface plasmon-polaritons. This work is focused on a procedure of light distributed, which by means of Kretschmann and Reather’s prism-based configuration, allows introducing the electromagnetic field in the junction, biased the insulator all along its length. In this way, the technique presented here introduces an improvement that increases the diode responsivity considerably.
The shape of general hospital nursing : the division of labour at work

This thesis is about nursing work and the ways in which nurses in a general hospital accomplished occupational jurisdiction. It is based on ethnographic data generated on a surgical ward and a medical ward in a single NHS trust hospital. The study is set in the context of recent developments in nursing and medical education (DHSS, 1987; GMC, 1993; UKCC, 1987) and health policy (DH, 1989) which have created the impetus for shifts in the division of labour in health care, reviving deep-rooted historical tensions between professional and service versions of nursing. Drawing on the work of Hughes (1984), Abbott (1988) and Strauss and colleagues (Strauss et al, 1963; Strauss et al, 1964; Strauss, 1978) the aim of this project was to move on from the policy debates and develop a less essentialist account of the nursing role through an exploration of the ways in which nurses managed the parameters of their work in the course of their everyday activities. Hughes concept of 'dirty work' is employed as a sensitising device. The work of hospital-based general nurses is explored through the analysis of five key nursing boundaries: nurse-doctor, nurse-support worker, nurse-patient/relative, nurse-nurse, and nurse-management. The professional and sociological literature suggested that as a result of recent policy developments, there would be an increased need for negotiation of nurses' inter-occupational boundaries with medicine and support workers and that this was likely to be subject to some tension. But field observations revealed that nurses accomplished these inter-occupational boundaries with minimal negotiation and little explicit conflict. Conversely, there were policy-related tensions at the three other key nursing boundaries - at nurses' infra-occupational boundary, at the boundary between nurses and patients and their relatives, and at the boundary between ward-based nurses and nursing and general management - which were largely unanticipated.
On the Evaluation of the Crazyflie Modular Quadcopter System

In recent years, quadcopters have become popular research platforms in the fields of robotics and control engineering. As a response to the academic community’s needs, several open-source hardware and software platforms have emerged with the aim to impose as de-facto development tools. One of these platforms is represented by Crazyflie 2.0, a nano class quadcopter that was used in research projects that span from control architecture designs to high-level swarm synchronization.This paper presents a study of the control architecture employed in the stock firmware. Based on the mathematical model, the dynamic behaviour is thoroughly evaluated to understand the deviation between ideal and real evolution. A comprehensive phase of parameters tuning is conducted and multiple scenarios for real-time testing are employed. These scenarios comply in tracking predefined patterns, the quadcopter’s evolution being tracked via a RGB-D sensor.The proposed evaluation procedure can be easily replicated and represents a very important step in obtaining accurate real-time results.
Accurate Terahertz Three-dimensional Subsurface Imaging by Range Points Migration Method

This paper proposes the novel imaging algorithm based on the range points migration (RPM) for the terahertz (THz) subsurface three-dimensional imaging. The inherent problem in the optical lens-based THz imaging system is the depth dependency for the azimuth resolution, and it is fatal, if the depth of object is not available in such as subsurface imaging issue. This paper newly introduces the range points migration (RPM) based auto-focusing algorithm, which is suitable for general THz-time domain spectroscopic (THz-TDS) measurement. The effectiveness of the proposed method has been validated through the THz-TDS measured data.
Learning Methods for the Feedforward Control of a Hydraulic Clutch Actuation Path

Hydraulic clutch actuation paths in heavy duty transmissions show a lot of variability due to series production variance, e.g. different friction. Additionally, there are external factors, such as the operators choice of hydraulic fluid or the compliance with specified service intervals. A further factor is the amount of entrained air that can vary from clutch to clutch in a single transmission. To address these effects, the authors recently proposed feedforward control concepts for the hydraulic clutch actuation path. While the feedforward controllers were shown to significantly improve the control quality, a manual parameter adaptation is necessary for optimal performance. Therefore, this paper presents and evaluates different learning algorithms. One algorithm based on rules and one based on multi-armed bandits that are suitable for a model-based control scheme. The third, a reinforcement learning algorithm based on policy gradients is suitable for a data-based feedforward control concept. In simulations with a high fidelity model, the improvement achievable in comparison with the state-of-the-art approach with all three algorithms is shown. In addition, the strengths and weaknesses of each algorithm are discussed.
Differential Optical Spatial Modulation Over Atmospheric Turbulence

Optical spatial modulation (OSM) is a multiple-input–multiple-output technique wherein the overall information is transferred through spatial and signal domains simultaneously. A problem in OSM is the necessity for channel state information at receiver (CSIR) that is obtained by complex channel estimation procedure. Apart from this, a small error in CSIR can cause a significant loss in the error performance of the OSM scheme. In this paper, in order to avoid the requirement of CSIR, a new scheme named as differential OSM (DOSM) is proposed; the average symbol error rate for the DOSM scheme with pulse-amplitude modulation is assessed under negative exponential and gamma–gamma channel models. A special and simplified version of DOSM, called as differential optical space shift keying is also discussed. It is noticed from the analysis that bypassing the requirement of CSIR leads to a small degradation in the error performance of DOSM scheme as compared to its traditional counterpart scheme with perfect CSIR. On the other hand, the proposed scheme outperforms OSM scheme with imperfect CSIR. Further investigations thoroughly examine the interplay between the error performance and spectral efficiency of the proposed scheme.
Consensus of Vehicle Platoon with the Hidden Layer Against Stochastic Noise

This paper concerns the consensus of the second order vehicle platoon system in presence of stochastic noise. The control protocol is designed to achieve the desired control objective under the predecessor-follower topology. The control objectives include: speeds of all vehicles in the platoon reach the consensus and the spacings between adjacent vehicles approach to be identical. Firstly, the necessary and sufficient conditions are obtained to reach consensus in the noise-free case. Then, the stochastic consensus of the platoon with the hidden layer is analyzed by using the knowledge of stochastic differential equation (SDE). The conditions of control parameters are derived to ensure the almost sure exponential consensus of the platoon. Finally, simulation experiments show the effectiveness of the proposed results.
Strengthening Security in Industrial Settings: A Study on Gaze-Based Biometrics through Free Observation of Static Images

As security becomes crucial in an increasing number of industrial contexts, the need arises for new ways to check or authenticate the identity of people. In this paper, we present a method that exploits gaze data to implement a soft biometric technique. Specifically, the user’s gaze behavior is inspected during the unconstrained observation of different kinds of static images. The obtained results, achieved using a machine learning approach, are generally satisfying, although more experiments will be necessary to fully confirm the viability of the proposed method.
Design and Evaluation of an Active Ankle Exoskeleton in Gait Assistance

Inspired by the energy storage and release mechanism of human’s Achilles tendon during walking, this paper proposes an ankle exoskeleton which is featured by adjustable stiffness of elastic elements to assist gait. The stiffness of the elastic elements can be switched to be consistent to the gait phase switching by a controllable clutch. The deformation range of the elastic element is increased by a linear driving mechanism in order to improve its energy storage ability. Plantar pressure and ankle motion are recorded to estimate the gait phase and switch the stiffness of the elastic elements. In order to evaluate the performance of the exoskeleton in gait assistance, the experiments were carried out on one subject. The result represents that whatever the stiffness of the elastic elements, the metabolic consumption of the subject can be reduced when the exoskeleton is actuated comparing with the situation of the exoskeleton non-actuation. The dominant muscle activities represent different decrease levels during walking with actuated exoskeleton.
MercuryDPM Adaptation for Electromagnetic Microscopic DEM Simulation

The purpose of this research is to create the adapted software for modeling microscopic electrodynamics processes. We use open source product codes MercuryDPM [1]. The basis of mathematical calculations and event processing is carried out by the method of discrete particles [2]. In the process of adapting the code, a number of fundamental models are considered: electron in a vacuum at rest, the electron moves in a vacuum as a non-relativistic particle and as a relativistic particle, the electron moves in the medium (gas, liquid, solid). The main types of interaction: electron – electron, electron – atom, electron – surface. This study is a synthesis of known processes into a single program. The project is limited in scope to the observed effects — it does not affect quantum effects (such as quantum particle scattering). The upper limit is macroeffects - such concepts of generalization as electric current, dielectric and magnetic permeability are excluded from the project. In this paper, we follow the general concept outlined in [3], but in the context of electrodynamics. The main output characteristic of the solver is the electromagnetic field emitted by the electron. We use the strict formulation [3]
Land of Lost Knowledge: An Initial Investigation into Projects Lost Knowledge

Background: Software development teams adopt various communication tools to support coordination and team interaction during the software development process. Among many other communication channels, developers’ use instant messaging to discuss ideas, decisions and other project related issues with team members. Due to the informal nature of instant messaging, many of these discussions and decisions are lost. This situation could be even more critical in startups and other software companies that rely more heavily on instant message tools or other informal communication channels.Aims: This work investigates the effectiveness of using a semiautomatic approach for identifying, extracting, and determining a project’s lost knowledge that was discussed using unstructured communication tools such as instant message.Methodology: We employed data-mining techniques to automatically retrieve discussions from instant message logs and showed them to the project managers to identify lost knowledge from two startup companies.Results: Our results demonstrate that the data-mining technique was capable of retrieving sentences with relevant issues discussion; reaching a precision of 75% at the first 10 relevant sentences evaluated. Moreover, the qualitative analysis conducted involving project managers shows an association of retrieved sentences with the project’s lost knowledge.Conclusion: Our findings indicate that automated approaches can be used to identify such lost knowledge in software development projects. Follow-up interviews revealed the interest of PMs in adopting such automated tools in other projects.
Group Pressure Leads to Consensus of Hegselmann-Krause Opinion Dynamics

A typical assumption concluded from the existing opinion formation models is that two individuals (agents) can communicate with each other only if the distance between their opinions is less than a threshold which is called confidence bound. However, in the real world, formation of opinion and expression may be different, for the reason that agent feels pressured to express opinion that is similar to the dominant opinion in the group. In this paper, a modified Hegselmann-Krause (H-K) model is introduced by integrating the opinion dynamics with confidence bound and group pressure, which describes the evolution of an individual’s opinion that conform to the dominant opinion under group pressure. We find that, when there is only one agent hold dominant opinion, the system can always achieve a consensus in a finite time regardless of the confidence bound value. In generalized case, we further establish a sufficient condition for multiple agents with dominant opinions, we prove that in this condition the whole group could also reach a consensus.
Double Resonator Topology for High Isolation and Low Insertion Loss in SPDT Switch

In this paper Double Resonator Topology is used to achieve high isolation and low insertion loss in single pole double through (SPDT) switch. This SPDT switch is based on GaAs MESFET and operates in the band of 8 to 11 GHz. This circuit is tuned to give optimum very high isolation and low insertion loss in 9-10 GHz frequency band. It uses one series and three shunt branches. One series and one shunt branch capacitances are resonated out with parallel inductance. This circuit is fabricated and performance measured. The measured performance of this MMIC SPDT switch has insertion loss lower than 2 dB and isolation better than 46 dB in 9-10 GHz and insertion loss lower than 2.2 dB and isolation better than 42 dB in 8-11 GHz. This circuit has to be integrated with other component to demonstrate X-band core chip.
Motor Imagination EEG Recognition Algorithm based on DWT, CSP and Extreme Learning Machine

Establishing an accurate and rapid electroencephalography (EEG) recognition algorithm is an important research direction in the field of Brain-Computer Interface (BCI). In this paper, EEG recognition algorithm is constructed based on discrete wavelet transform (DWT), common spatial patterns (CSP) and extreme learning machine (ELM). DWT and CSP are used for joint feature extraction, which solves the problem that traditional CSP is sensitive to noise. ELM is used for classification, which improves the real-time performance of the BCI system. Our findings show a classification accuracy of 90% and a classification time of 0.012s for the Data Set III in BCI Competition 2003, which proves the effectiveness of the algorithm.