Miracle-dz/UniFAR-FTUs huggingface dataset:
Modeling and identification of electromagnetic actuator for the control of rotating machinery

This work deals with the design and the assessment of electromagnetic actuators (EMAs) for the control of rotating machines. The system studied has a hybrid bearing that exhibits nonlinear behavior. The system is composed of a horizontal flexible shaft supported by two ball bearings at one end and a roller bearing that is located in a squirrel cage at the other end. Four identical EMAs supplied with constant current are utilized. The EMAs associated to the squirrel cage constitutes the hybrid bearing. The aim is to develop a strategy in order to define and to identify a reliable model necessary for the control of rotating machinery in the presence of localized non-linearity. The identification strategy consists in modeling the system with as many sub-models as needed that are identified separately. This enables obtaining a straightforward modeling of rotating machinery even in the case in which system components are frequency or time dependent. For the system studied, two sub-models were necessary. First the EMAs were modeled by using classical equations of electromagnetism and then identified experimentally. Then, a linear model of the shaft mounted on its bearings was defined by using the finite element method and was identified successfully. The model of the system was adjusted after assembling the different identified sub-models. The identification is carried out by using a pseudo-random search algorithm. The model of the system is then assessed for different configurations. The results obtained demonstrate the effectiveness of the developed strategy.
Enhanced thermopower and thermoelectric performance through energy filtering of carriers in (Bi2Te3)(0.2)(Sb2Te3)(0.8) bulk alloy embedded with amorphous SiO2 nanoparticles

(Bi2Te3)0.2(Sb2Te3)0.8 (BST) based nanocomposites dispersed with amorphous SiO2 (a-SiO2) nanoparticles (∼50 nm) were fabricated and their thermoelectric properties were investigated in the temperature range from 293 K to 490 K. The results indicate that with increasing volume fraction of a-SiO2 from f = 0 to 0.55, 1.10, and then to 2.20 vol. %, the electrical resistivity ρ of the nanocomposites f(a-SiO2)/BST decreases first (f = 0.55 vol. %) and then increases rapidly with further increasing a-SiO2 content, which is proved to be caused mainly by changes of carrier concentration. In contrast, Seebeck coefficient S for the nanocomposites increases monotonically with increase in f, specially at T < ∼380 K, suggesting that at low a-SiO2 (f = 0.55 vol. %) content, at least, the increase in S of the nanocomposite could be ascribed to energy filtering effect arising from enhanced carrier scattering by the interface potentials due to the embedded a-SiO2 nanoparticles. Owing to both increased power factor (S2/ρ) and reduced thermal conductivity caused by phonon scattering of nanoparticles as well as phase boundaries, the dimensionless figure of merit ZT of f(a-SiO2)/BST composite sample with f = 0.55 vol. % enhanced substantially at T < 390 K; specifically, ZT of the composite sample reaches 1.12 and 1.27 at ∼303 K and ∼363 K, respectively, which is, respectively, ∼27% and ∼20% larger than that (0.88 and 1.06) of BST, demonstrating that thermoelectric performance of BST can be effectively elevated by incorporation of a-SiO2 nanoparticles.
Analyses of infiltration events in relation to determining soil hydraulic properties by inverse problem methodology

At the field scale, because of the relatively large number of observation points required to estimate the spatial distributions of hydraulic properties, application of inversion procedures must be based on a characteristic of the flow that for a given point in the field can be measured with relative ease, and can be used as input for the inversion procedure. Suggesting the use of infiltration data for this purpose, and recognizing the fact that a basic requirement for the design of a transient flow experiment is that the resulting inverse problem be sufficiently well posed to allow solution, this paper addresses the question under which circumstances the resulting inverse problem is well posed, utilizing the concepts of identifiability, uniqueness, and stability. For this purpose, three different models of the soil hydraulic properties were analyzed. The main conclusion of this study is that when infiltration data measured at the Darcy scale are used as input for the inversion procedure, the inclusion of prior information on a single measurable parameter, the saturated conductivity Ks, in the estimation criterion will enhance the likelihood of uniqueness and stability of the inverse solution provided that the structure of the hydraulic model is sufficiently simple. However, since for a particular situation, it is impossible to determine a priori whether the resultant inverse problem is well posed or not, this must be carried out only a posteriori by solving the problem several times with different initial parameter estimates, accompanied by an analysis of the associated estimation errors.
Fluorescent optical liquid level sensor

A liquid level sensor comprising a transparent waveguide containing fluorescent material that is excited by light of a first wavelength and emits at a second, longer wavelength. The upper end of the waveguide is connected to a light source at the first wavelength through a beveled portion of the waveguide such that the input light is totally internally reflected within the waveguide above an air/liquid interface in a tank but is transmitted into the liquid below this interface. Light is emitted from the fluorescent material only in those portions of the waveguide that are above the air/liquid interface, to be collected at the upper end of the waveguide by a detector that is sensitive only to the second wavelength. As the interface moves down in the tank, the signal strength from the detector will increase.
An Error Estimate for the Finite Element Solution of an Elliptic Problem with a Nonlinear Newton Boundary Condition in Nonpolygonal Domains

Abstract The article is concerned with the study of an elliptic boundary value problem with a nonlinear Newton boundary condition considered in a two-dimensional domain with a curved boundary. The existence and uniqueness of the weak solution of the continuous problem is a consequence of the monotone operator theory. The problem is discretized with the use of the finite element method. The main attention is paid to the effect of the approximation of the curved boundary by a piecewise linear boundary and of the evaluation of integrals by numerical quadratures. With the aid of some important properties of Zlámal's ideal triangulation and interpolation, the error estimate for the solution of the discrete problem is derived.
On melting criteria for complex plasma

The present paper considers melting criteria for a plasma crystal discovered in dust plasma in 1994. Separate discussions are devoted to three-dimensional (3D) and two-dimensional (2D) systems. In the 3D case, melting criteria are derived based on the properties of local order in a system of microparticles. The order parameters are constructed from the cumulative distributions of the microparticle probability distributions as functions of various rotational invariants. The melting criteria proposed are constructed using static information on microparticle positions: a few snapshots of the system that allow for the determination of particle coordinates are enough to determine the phase state of the system. It is shown that criteria obtained in this way describe well the melting and premelting of 3D complex plasmas. In 2D systems, a system of microparticles interacting via a screened Coulomb (i.e., Debye–Hückel or Yukawa) potential is considered as an example, using molecular dynamics simulations. A number of new order parameters characterizing the melting of 2D complex plasmas are proposed. The order parameters and melting criteria proposed for 2D and 3D complex plasmas can be applied to other systems as well.
Nonlinear Hysteretic Dynamic Response of Soil Systems

A simplified analysis procedure for the nonlinear hysteretic dynamic response of soil or structural systems, or both, is presented. The method is based on a Galerkin formulation of the equations of motion in which the solution is expanded using basis functions defined over the spatial domain occupied by the soil system. The basis functions are selected as the normal eigenmodes of the linearized problem. The hysteretic stress-strain behavior is modeled by using elastoplastic constitutive equations based on multi-surface kinematic plasticity theory. Accuracy and versatility of the technique are demonstrated by applying it to analyze the nonlinear dynamic response of an earth dam. The dam is modeled as a one-dimensional hysteretic shear wedge. Parametric studies assessing the influence of the nonlinearities on the response are presented. Finally, comparisons are made with results obtained through a more elaborate finite element representation of the dam.
Simulation and Fabrication of SU-8 Microfluidics Mixers capped by Wafer-to-Wafer Bonding

In addition to other technologies, microsystems technology is now proving to be an important key technology for the realization of new life science applications. The transition between the two scientific fields is fluently. An important area of application of the manufacturing processes of microsystems technologies in life sciences is e.g., the production of complex microfluidic structures and micromixers. In this work, the design, simulation and the manufacturing process of micromixers will be presented. The mixing behavior of different microfluidic designs are simulated using ANSYS Fluent. In addition, certain parameters of the mixer are considered theoretically in order to verify the results of the simulations. A process development manufactured on wafer level, including spincoating, bonding and laser-drilling has been done, to gain different types of micromixers as demonstrators. Finally, the simulation results are compared with the results of the micromixers.
On the Three-Dimensional Finite Element Analysis of Dovetail Attachments

The stress analysis of dovetail attachments presents some challenges. These stem from the high stress gradients at the edges of contact. They also stem from the nonlinearities accompanying conforming contact. Even with two-dimensional analysis, obtaining converged peak stresses is not trivial. With three-dimensional analysis, convergence can be expected to be more difficult to achieve because of the added computational costs of refinement in three dimensions. To meet these challenges, this paper describes a submodeling procedure with finite elements. The submodeling approach features bicubic surface fits to displacements for submodel boundary conditions. The approach also features a means of verifying these boundary conditions have converged; this is crucial to obtaining accurate converged peak stresses. The approach is applied to a three-dimensional test piece used to simulate a dovetail attachment. This application leads to converged three-dimensional stresses. These stresses serve to quantify the sort of increases in contact stresses in attachments due to three-dimensional effects.
Arrow's Theorem for Economic Domains and Edgeworth Hyperboxes

Kenneth J. Arrow's theorem holds when the set of alternatives is an Edgeworth hyperbox and the individuals have classical economic preferences over their consumption sets. (Free disposability is not assumed.) By classical individual preferences the authors mean preorders satisfying continuity, strict convexity, strict monotonicity, and selfishness. A minor, but noteworthy, accomplishment is the development of a general technique for extending two-commodity impossibility theorems to the general m-commodity counterpart. Copyright 1995 by Economics Department of the University of Pennsylvania and the Osaka University Institute of Social and Economic Research Association.
A Distributed Control Law for Acyclic Formations

Abstract New distributed control laws using relative positions are proposed to control a formation of mobile autonomous agents in the plane. When the formation is generated by Henneberg sequence operations, control laws proposed here are capable of driving it to its desired shape even when the triangular sub-formations are initially formed by some collinear neighboring agents or in the wrong orientations. We prove that the conclusion holds globally and further validate it by simulations.
A curvilinear search algorithm for unconstrained optimization by automatic differentiation

Solving in an efficient and robust way an unconstrained optimization problem may prove quite hard in certain difficult situations. Typical examples are highly nonlinear problems, ill-conditioned and badly scaled problems. Particularly in these situations, it may be useful to compute a curvilinear trajectory and follow it by curvilinear searches with the aim to reach the solution in few long steps. In this paper, we proposed an approach for computing a suitable curvilinear trajectory, based on the knowledge of the third order derivatives of the objective function. The numerical implementation of this approach was made possible by Automatic Differentiation techniques. Some preliminary numerical results are very encouraging, especially in the case of very ill-conditioned and badly scaled problems.
THE VARIABILITY OF GAUSS SHA COEFFICIENTS USED IN THE DETERMINATION OF THE ELECTRICAL CONDUCTIVITY OF THE UPPER MANTLE FROM QUIET DAY CURRENT

Quiet day (Sq) ionospheric current variation has been discovered to be a powerful tool in determination of upper mantle electrical conductivity. Gauss spherical harmonic analysis technique is employed. This method involves the separation of the Gauss spherical harmonic analysis coefficients into its external and internal contributions. The variability of these coefficients as they are used in the electrical conductivity determination of the upper mantle in L'Aquila Italy, has been investigated. L'Aquila is located at geographic latitude 42˚23' and longitude 13˚19'E. Its geomagnetic coordinates are 42. 5˚N and 94.3˚E. Sq data obtained from the geomagnetic observatory at L'Aquila in 1995, 1996 and 1997 were used for the investigation. The mean spherical harmonic analysis coefficients generated from the data were evaluated and used to obtain the conductivity-depth profile of the location. The conductivity values at specific depths of the upper mantle including 280km, 420km and 650km were estimated. At 280km depth the conductivity in 1995, 1996 and 1997 were observed to be 0.15, 0.14 and 0.15 S/m respectively. At 420km, the conductivity values are 0.28, 0.26 and 0.27 S/m respectively and at 650km, the values are 0.36, 0.30 and 0.36 S/m for 1995, 1996 and 1997 accordingly. A comparison of the conductivity estimates with the SHA coefficients indicates that while the electrical conductivity of the upper mantle is constant with respect to depth and independent of time, the spherical harmonic analysis coefficients showed remarkable year-to-year variability.
Variable-Number Differential Evolution and its Application on Uranium Ore Classification

Differential Evolution (DE) algorithm is a heuristic random search algorithm based on the group difference, and it is also an optimization algorithm which processes random search in the continuous space with actual number vector coding. In uranium ore classification, its impossible to know in advance the number of best features to select. This paper puts forward a new algorithm named Variable-number Differential Evolution (VDE) algorithm, and applies it to selecting the best features of hyperspectral data. Then applies k-nearest neighbor, decision tree, naïve bayes, naïve bayes tree and support vector machine algorithm on the newly obtained data set only containing the selected features, records average accuracy by 10-fold cross-validation. The results show that new algorithm can improve the accuracy of classification compared with genetic algorithm (GA) and original DE algorithm.
Reconnection of two vortex rings

The reconnection of two identical viscous vortex rings is investigated numerically. The initial state consists of two rings (of Re≡Γ/ν=578) of a circular cross section placed side by side in a periodic box with their coplanar axes inclined by 30° to the symmetric plane. The subsequent motion is examined by solving the Navier–Stokes equation by a dealiased pseudospectral method in a 643 box. We found two prominent reconnection processes: first, the two vortex rings merge into one by viscous annihilation of opposite vorticity and second, two new rings, which are connected by two ‘‘legs,’’ are created by bridging. The apparent differences with laboratory experiments are discussed.
Performance of Z-type hexagonal ferrite core under demagnetizing and external static fields

The effects of a demagnetizing field and an external static magnetic field on the effective Snoek’s product of textured Z-type hexagonal ferrite, which is the product of effective susceptibility and resonance frequency, were examined in order to apply the Z-type hexagonal ferrite to high-frequency devices. As a result, the demagnetizing field due to the thin plate geometry increased the resonance frequency and the effective Snoek’s product when a high-frequency magnetic field was applied parallel to the c-plane of the Z-type hexagonal ferrite. Moreover, the resonance frequency, effective susceptibility, and effective Snoek’s product of 7.7 GHz, 10.7, and 82.2 GHz, respectively, were obtained when an external magnetic field that was sufficient to saturate the Z-type hexagonal ferrite slab was applied parallel to the c-plane and perpendicular to the high-frequency magnetic field. Furthermore, the Landau–Lifshitz equation suggested that a large Snoek’s product of over 50 GHz could be obtained with an externa.
Parameterizable mobile workloads for adaptable base station optimizations

Recent works on 5G baseband processing systems address the optimization of applications with different require-ments of quality of service (QoS). The volume and heterogeneity of applications that have to be processed on a base station are growing and 5G introduces new use cases that push system designers towards more flexible and adaptable approaches. To investigate future network challenges of mobile communications, a good methodology for the generation of realistic workloads, that allows target optimizations of different traffic scenarios, is required. In this paper, we study the variation of real traffic data on multiple base stations and identify the main sources for the high variation of the 5G workloads. We propose a methodology for parameterizable workload generation for users with different QoS requirements that enables optimization techniques in base-band processing systems. We demonstrate the feasibility of our approach based on a virtual base station using a heterogeneous hardware model and various state-of-the-art mapping policies.
Design and Experiments of a Modular Dexterous Hand

The goal of the existing dexterous hands is to achieve multi-function, compact structure, and simple control, which makes it difficult to be installed and disassembled, and the application of fingers is limited. In order to realize the flexibility and convenience of dexterous hand application, this paper proposes the design and experiments of a modular dexterous hand based on human hand biology. Firstly, the movement characteristics of the human hand are combined with its biological tissue structure to analyze its movement laws. The synergy and independence of finger movements were summarized. Secondly, based on the biological proper-ties of the human hand, a design method for a modular dexterous hand is proposed. The flexion and extension (F /E) of the finger adopts the design method of compliance drive and flexible coupling, so that it can achieve great adaptability to the object. Combined with independent adduction and abduction (Ad/ Ab), the dexterity of the fingers is guaranteed. Finally, through the rapid combination of modular fingers, two-fingered hand, three-fingered hand, and humanoid hand were developed, and grasping and manipulation experiments were carried out to verify the feasibility of the design.
Fast Inter Prediction Mode Decision Method Based On Random Forest For H.266/VVC

In H.266/VVC, many new tools are introduced in the inter prediction process. These new techniques enable the encoder in H.266/VVC to predict motion vectors more accurately, but inevitably increase the coding complexity. To solve this problem, in this paper, we propose an early termination algorithm for inter prediction based on random forest which is characterized by the information provided by the temporal co-located block and the spatial adjacent block of the current Coding Unit (CU). Specifically, the random forest is used to predict whether the inter prediction process of the current CU will be terminated in advance. Our proposed algorithm is implemented on Fraunhofer Versatile Video Encoder (VVenC). Experimental results have shown that, in the Random Access (RA) mode, the encoding time of VVenC is reduced by 7.71 % on average while Bjontegaard Delta Bit Rate (BDBR) increases by 1.48 %.
Recognizing Confusion in Assembly Work based on a Hidden Markov Model of Gaze Transition

A method to detect the states of confusion during an assembly work for a user-adaptive work support system is proposed in this study. The eye-gaze data from an eye tracker are discretized into predefined areas of interest, and a hidden Markov model is used to classify the cognitive states associated with confusion and types of work steps involved. An offline experiment using data collected from 16 participants showed low task dependency (F1-scores of 0.638 and 0.639 for dependent and independent evaluations, respectively) and relatively high person dependency (F1-score of 0.621 for independent evaluation). The high discriminability between the two assembly steps and tendency of misclassification in confused states were confirmed.
Low Overhead Drone Relaying in Dense Urban and Suburban Environments

This paper studies a drone relay assisted cooperative wireless communication system. Specifically, a drone is used as the relay node to establish communication between the base station and an aerial mobile terminal under realistic channel models with the consideration of line-of-sight probability. The total transmission time is divided into smaller time slots and in each time slot the relay uses decode-and-forward protocol to forward the received information to the mobile terminal. Then, an optimization problem is formulated where the objective is to maximize the sum rate over the whole transmission time. The formulated problem is non-convex. However, we show that for several cases the global optimal solution can be achieved. Moreover, we develop a low-complexity algorithm to find suboptimal solutions for the other cases.
LiDAR-Based Safe and Realistic Path Planning in Partially Observable Environments

The difficulty of the robot’s navigation task in a partially observable environment is to find the optimal collision-free path with limited information. However, the traditionally used path planning algorithm finds the optimal path, but cannot directly account for robot collisions. We propose a method that directly considers collisions and efficiently finds short realistic paths. The proposed method is confirmed to be effective for robots to find short realistic paths in partially observed environments.