Miracle-dz/UniFAR-FTUs huggingface dataset:
A Collaborative Path Planning Method for Heterogeneous Autonomous Marine Vehicles

Intelligent control of autonomous marine vehicles (AMVs) is one of the essential technologies for exploring marine resources. In the deep sea with a complicated exploration environment, collaboration between heterogeneous AMVs can maximize exploration efficiency by utilizing various functional benefits. Accordingly, this article proposes a method for collaborative path planning for heterogeneous AMVs that employs a fused metaheuristic algorithm for the underwater path planning of an autonomous underwater glider (AUG), and an adaptive surface path planning of an autonomous surface vehicle (ASV), respectively. The fused metaheuristic method balances global and local path explorations for underwater path planning by integrating the gray wolf optimizer (GWO) and equilibrium optimizer (EO), and it reduces the local optimum problem by using a conditional convergence factor; and the adaptive surface path planning approach considers the influence of ocean currents at various locations to guide the ASV collaboratively to track the AUG underwater in the horizontal plane. The fused metaheuristic algorithm has demonstrated superior convergence performance in simulations, which indicates that the proposed method has advantage in terms of underwater path planning for complex marine exploration.
Towards distributed multi-target tracking using teams of mobile robots

Multi-Robot Multi-Target Tracking (MR-MTT) addresses the problem that a swarm of mobile robots actively detect and move to maintain surveillance of a team of dynamic targets, which is a fundamental problem in the modern robot system and has enormous potential in numerous fields. This paper investigates a series of MR-MTT algorithms, with detailed demonstrations of two distributed approaches to solving MR-MTT in finite iterations. On the one hand, a novel local algorithm is introduced to solve multi-robot multi-target assignments within limited communication rounds. On the other hand, an innovative coverage control algorithm combined with a probability hypothesis density (PHD) filter for target estimation is derived to settle detection and tracking tasks simultaneously. Both algorithms are analysed and discussed mathematically, with simulation experiments demonstrating their efficacy and performance. It is concluded that both algorithms solve the MR-MTT problem in terms of optimal coverage and optimal target estimation, respectively.
Investigation of the Flow Around an Aircraft Wing of Section NACA 2412 Utilising ANSYS Fluent

The aim of this paper is to produce and validate a simulated model of the external flow around the NACA 2412 using ANSYS Fluent; utilising experimental data for a low velocity case (20.73 m/s) from literature. This model will be subsequently used to produce data for a high velocity case (272.1 m/s, Mach = 0.8) which is the practical velocity for commercial aircraft. Both an infinite aspect ratio wing (2D) and a finite aspect ratio wing (3D) will be the subjects of this investigation. Experimental data on which the simulated models will be compared and hence validated is taken from Jacobs et al. [1]. This experimental data contains both a finite aspect ratio wing and an infinite aspect ratio wing. An accurate simulation model of the external flow around a wing will be beneficial in the visualisation of the flow; particularly in the investigation of the onset of a stall and the aerodynamic characteristic differences between the wing root and wing tip. The model will also provide simulated data of an external flow condition of which no experimental data currently exists. Finally, value will be gained in the investigation between the differences of an external flow around a 2-dimensional (2D) wing versus a 3-dimensional (3D) wing. All simulations exhibited flow physics consistent with those seen in experimental data; further validating the results. A detailed methodology has been provided with a view that new data becomes available for this aerofoil and wing geometry. Considering the aerofoil simulation, incredible accuracy has been achieved. However, with regards to the wing simulation, further work is required to identify the issue which resulted in a lower lift curve slope when compared to the experimental data.
Multi‐Objective Optimization Models for the Design of Water Distribution Networks by Exploring Scenario‐Based Approaches

Demand in a water distribution network (WDN) is an aleatory variable, owing to the unpredictable behaviors of water users. Therefore, it is one of the main reasons for uncertainty in the design of this infrastructure. The increasing number of water demand data sets offers opportunities to improve the traditional deterministic design approaches of WDNs by combining statistical and optimization methods. Robust optimization (RO) takes demand uncertainty into account by studying solutions that perform well under any possible demand scenario, that is, any possible realizations of this variable in the lifetime of a WDN. The right choice of scenario is therefore essential to ensure the reliability of the designed network. This paper presents a statistical methodology for generating scenarios to be used to solve a robust design optimization problem. It involves three steps: (a) descriptive analytics of historical data to derive the marginal distributions of peak hour demand in each node of the WDN, (b) generation of a very large number of snapshots by stratified sampling from the correlated marginal distributions of nodal peak demand, (c) generation of the peak demand scenarios by reducing the number of snapshots. Two heuristic techniques are proposed to reduce the number of snapshots, and for each of them, two different numbers of scenarios are derived. Two multi‐objective RO models are solved: the first model includes cost minimization and a mean‐variance Generalized Resilience and Failure index maximization objectives, and the second one additionally considers the minimization of the maximum undelivered demand, formalized using a regret function.
The approach to investigation of the the regions of self-oscillations

Self-oscillating modes in control systems of computer networks quite negatively affect the characteristics of these networks. The problem of finding the areas of self-oscillations is actual and important as the study of parameters of self-oscillations. Due to the significant nonlinearity of control characteristics, the study of the self-oscillating modes presents certain difficulties. This paper describes the technique of research of self-oscillating modes.
Uncovering Gas Insulated Substation Transient Behaviours Using the Equivalent Cable Model

An improved circuit theory approach is proposed for verification of data obtained with the Electro-Magnetic Field (EMF) theory for the study of Gas Insulated Substations (GIS) transient behaviours. The improved circuit theory utilises the concept of an equivalent cable model. The proposed equivalent cable model reduces time and eliminates costs associated with experimentation, which in some cases is not feasible. Also reported is the degree of accuracy in using the proposed model as a benchmark for verification purposes.
One-dimensional model for axial thermal error in a micro high-speed spindle

This article proposes a robust and accurate axial thermal error model for a micro high-speed spindle. With measured temperatures, an inverse method is applied to obtain the heat source and temperature field in the spindle for demonstrating that there exists a uniform temperature distribution along the axial direction within the motor range. Hence, a simple one-dimensional heat transfer model is established to acquire the temperature and resulting thermal errors using only one measured temperature on housing surface. Jumped displacement when the spindle starts and stops and the nonlinear deformation on the bearings are satisfactorily treated in the model. The results show that the estimated thermal errors agree with the measured data for both constant and various speeds. In addition, the results reveal that spindle speed significantly affects the maximum thermal error. A short processing time is an advantage of the proposed method. The model promises effective integration in machine tools for compensating thermal errors.
GAN-in-GAN for Monaural Speech Enhancement

Some generative adversarial networks (GANs) have been developed to remove background noise in real-world audio recordings. MetricGAN and its variants focus on generating a clean spectrogram from a noisy one, but the final audio quality can't be guaranteed. SEGAN and its variants directly generate an enhanced audio from a noisy one, but their over-long input representations make it less effective in identifying and removing audio noise. In this letter, a novel GAN-in-GAN framework is proposed, where the inner GAN conducts spectrogram-to-spectrogram recovery under the supervision of metric discriminators to effectively clean the audio noise, and the outer GAN conducts an audio-to-audio recovery under the supervision of multi-resolution discriminators to optimize the final audio quality. To tackle the challenges of utilizing multiple adversarial losses for training the proposed GAN-in-GAN simultaneously, a novel gradient balancing scheme is proposed to facilitate a coherent training. The proposed method is compared with state-of-the-art methods on the VoiceBank+DEMAND dataset for audio denoising. It outperforms all the compared methods.
Performance Optimization of Carbon Nano-Tube Field Effect Transistors by Tuning Parameters

As transistors are scaled down to keep up with Moore's law, the semiconductor industry is facing several challenges due to the limitation of traditional Metal Oxide Semiconductor Field Effect Transistor (MOSFET) technology. To overcome this issue of scalability, various other technologies are being researched. Among them are Carbon Nano-Tube Field Effect Transistors (CNTFET), Ribbon Field Effect Transistors (RibbonFET), Graphene Nanoribbon Field Effect Transistor (GNRFET), and Fin shaped Field Effect Transistor (FinFET), which can substitute MOSFETs. Due to carbon nanotubes' excellent conductivity supremacy, CNTFETs are a promising new solution. However, implementing a CNTFET and making circuits from it is still challenging as CNTFETs can exhibit properties of both semiconductor and metal depending on various parameters. This paper will illustrate the characteristics of the CNTFET, compare the power consumption and propagation delay of basic logic gates made using the CNTFET and MOSFET technology. The parameter tuning is done by measuring the power and delay for all parameter values. The Simulation of CNTFET is done on the Stanford CNTFET model using H-Spice.
A high speed PE-ALD ZnO Schottky diode rectifier with low interface-state density

Zinc oxide (ZnO) has recently attracted attention for its potential application to high speed electronics. In this work, a high speed Schottky diode rectifier was fabricated based on a ZnO thin film deposited by plasma-enhanced atomic layer deposition and a PtOx Schottky contact deposited by reactive radio-frequency sputtering. The rectifier shows an ideality factor of 1.31, an effective barrier height of 0.79 eV, a rectification ratio of 1.17 × 107, and cut-off frequency as high as 550 MHz. Low frequency noise measurements reveal that the rectifier has a low interface-state density of 5.13 × 1012 cm−2 eV−1, and the noise is dominated by the mechanism of a random walk of electrons at the PtOx/ZnO interface. The work shows that the rectifier can be used for both noise sensitive and high frequency electronics applications.
Structural, Electronic and Magnetic Properties of Silicene Substituted with Monomers and Dimers of Cr, Fe and Co

Extensive full-potential density functional theory calculations were performed to investigate the structural, electronic and magnetic properties of silicene substituted with monomers and dimers of Cr, Fe and Co atoms. Different concentrations of monomers between 1 and 12 percent were considered. The structures substituted with all concentrations of Fe were metal and showed magnetic properties. The structures substituted with Co and Cr were half-metal or metal and, surprisingly, silicene substituted with 1.4 percent Co did not show a magnetic moment. Homonuclear and heteronuclear dimers of the above atoms were investigated for two different substitution positions in silicene. The structures showed metallic or half-metallic properties and a range of magnetic moments from 0 to 6 . This variety of electronic and magnetic properties suggest that metal-substituted silicene materials could play essential roles in nano-electronic devices in fields such as spintronics.
Quality aspects of distributed scatterers in polarimetric differential SAR interferometry

Ground deformation measurements have contributed to a better understanding of the processes and mechanisms involved in natural hazards. Those include landslides, subsidence, earthquakes and volcanic eruptions. Spaceborne Differential Interferometric Synthetic Aperture RADAR (DInSAR) is a well studied technique for measuring ground deformation. Quality of deformation measurements, however, is often degraded by decorrelation. With the advent of fully polarimetric SAR satellite sensors, polarimetric optimization techniques exploiting polarimetric diversity improve the phase quality of interferograms. In this paper, we analyzed three polarimetric optimization methods to determine the optimal one for application in an arid natural environment. We considered coherence decomposition in single and double phase center scenarios. Coherence and differential phase bias associated with each optimization method has been analyzed. We compared the derived displacement values with terrestrial GPS measurements. The study shows that polarimetric optimization increases the number of coherent pixels by upto 6.89% as compared with a single polarization channel. The study concludes that polarimetric optimization coupled with DInSAR analysis yields more reliable deformation results in a low coherence region.
Model‐free optimal tracking over finite horizon using adaptive dynamic programming

Adaptive dynamic programming (ADP) based approaches are effective for solving nonlinear Hamilton–Jacobi–Bellman (HJB) in an approximative sense. This paper develops a novel ADP‐based approach, in that the focus is on minimizing the consecutive changes in control inputs over a finite horizon to solve the optimal tracking problem for completely unknown discrete time systems. To that end, the cost function considers within its arguments: tracking performance, energy consumption and as a novelty, consecutive changes in the control inputs. Through suitable system transformation, the optimal tracking problem is transformed to a regulation problem with respect to state tracking error. The latter leads to a novel performance index function over finite horizon and corresponding nonlinear HJB equation that is solved in an approximative iterative sense using a novel iterative ADP‐based algorithm. A suitable Neural network‐based structure is proposed to learn the initial admissible one step zero control law. The proposed iterative ADP is implemented using heuristic dynamic programming technique based on actor‐critic Neural Network structure. Finally, simulation studies are presented to illustrate the effectiveness of the proposed algorithm.
Calculation of Average Characteristics of Water Environment Stratification

Problems arising at applying traditional procedure for averaging hydrophysical characteristics’ vertical profiles are analyzed. The conclusion on necessity of taking into account vertical displacements of fluid elements is drawn. For this purpose, the Lagrangian invariants, (particularly, the averaged background distribution of the density field) are proposed to be applied. It permits to calculate the averaged depths of the vertical structure various elements. If the fluid is stratified the surfaces of constant density is called isopycnal. They nowhere intersect and divide the fluid into the layers. In the ideal fluid (when the processes of diffusion/exchange are absent), its elements never cross the isopycnal surfaces. Note that in real ocean the exchange processes are always present. As a result the fluid element density can change; thereupon it leaves its isopycnal level. Therefore the in situ density is not the true Lagrangian invariant. The average value for each element corresponding to the average depth of this element is used as an average vertical distribution of a sought parameter. The means for increasing reliability of the stratification elements’ identification and applicability of the proposed method are discussed. The present method developed based on the thermodynamics general principles can also be applied for averaging the atmosphere parameters and the laboratory experiments. Besides, use of density as the Lagrangian invariant is not obligatory. The basic advantage of such a choice is conditioned by its monotonous dependence on depth. As well as for the ocean, in case there are uniformities of the parameter vertical gradient which permits to identify the stratification elements, additional background averaging can be used. The averaging vertical scale has to exceed the characteristic scales of small heterogeneities (for example, high-gradient streaks), but it is to be smaller than the background heterogeneities’ scales (mixed layers’ thicknesses). In case the denoted gradient heterogeneities are absent additional averaging is not required.
Design and comparative performance analysis of different chirping profiles of tanh apodized fiber Bragg grating and comparison with the dispersion compensation fiber for long-haul transmission system

Abstract Various dispersion compensation units are presented and evaluated in this paper. These dispersion compensation units include dispersion compensation fiber (DCF), DCF merged with fiber Bragg grating (FBG) (joint technique), and linear, square root, and cube root chirped tanh apodized FBG. For the performance evaluation 10 Gb/s NRZ transmission system over 100-km-long single-mode fiber is used. The three chirped FBGs are optimized individually to yield pulse width reduction percentage (PWRP) of 86.66, 79.96, 62.42% for linear, square root, and cube root, respectively. The DCF and Joint technique both provide a remarkable PWRP of 94.45 and 96.96%, respectively. The performance of optimized linear chirped tanh apodized FBG and DCF is compared for long-haul transmission system on the basis of quality factor of received signal. For both the systems maximum transmission distance is calculated such that quality factor is ≥ 6 at the receiver and result shows that performance of FBG is comparable to that of DCF with advantages of very low cost, small size and reduced nonlinear effects.
Robust output-feedback finite-time regulator of systems with mismatched uncertainties bounded by positive functions

In this study, the authors investigate the problem of finite-time output regulation for a class of mismatched uncertain n-dimensional integrator, in which only the output signal is measurable and the higher derivatives of the matched and mismatched disturbances are bounded by time-varying functions. Based on a finite-time extended state observer, an output feedback controller is constructed. It is shown that even in the presence of mismatched uncertainties, whose high-order derivatives are bounded by positive functions, the output of the system can be regulated to zero in finite time without requiring the knowledge of full-state signals. An application to mass-spring mechanical systems is given to illustrate the effectiveness and attractive properties of the authors' proposed controller.
Enshrouded exoplanetary systems

This thesis is based on the hypothesis that stars hosting short period planets can show anomalously low apparent stellar activity values caused by planetary mass-loss enshrouding the system. The resulting circumstellar absorption depresses the cores of the Ca II H&K lines, where the activity index log(R'HK) is measured. I searched for this effect in a sample of ∼2700 stars, identifying 39 objects with log(R'HK) below the main sequence basal limit, and 6 Hyades and Pleiades stars with activity levels well below the cluster distributions. I describe a radial velocity programme to search for short period planets orbiting these stars. Because nearby bright stars are targeted, their mass-losing companions will offer key opportunities to probe planetary composition through transmission spectroscopy. I present four planet candidates discovered through this programme orbiting HD11231 and HD38677. The former is a γ-Doradus pulsator hosting a Saturn-mass planet in a 6 day orbit, and the latter is a compact system containing planets with ∼18, 13 and 3 Earth masses and periods between 20 and 1.7 days. In addition, the Robert Stobie Spectrograph was calibrated to measure log(R'HK) values. The activity index of the known Hot Jupiter hosts WASP-43, WASP-51/HAT-P-30, WASP-72 & WASP-103 was measured to search for anomalous values caused by the companions. The activity level of WASP-43 is extremely high in absolute terms and relative to its age and X-ray emission. The activity of WASP-103 is marginally higher than expected from the system age. In both cases, star-planet interactions may enhance Ca II H & K emission. WASP-51/HAT-P-30 and WASP-72 show anomalously low activity; the latter falls below the basal envelopes of main sequence and evolved stars. I highlight that a quarter of transiting, short period planets hosts with published activity data exhibit anomalously low activity. These 22 systems include Hot Jupiters and low mass companions.
LICENSING AND ENFORCEMENTIN MUNICIPAL ENVIRONMENTAL DEPARTMENTS IN THE STATE OF RIO GRANDE DO SUL, BRAZIL

This study evaluated the environmental departments of some municipalities in Rio Grande do Sul, Brazil, regarding their structure and licensing and enforcement processes. Information was collected through online questionnaires sent to municipalities. The questionnaires addressed the staff, the training of the technical staff and the work structure of the environmental departments in the municipalities. Evaluations and classifications were conducted using the classification tree technique based on municipal data on the environmental licenses issued, and additionally the infraction notices issued as response variables. Thus, it was observed that human resources, effective civil servants and the work team composition are the variables that best explain the issuance behavior of the municipal environmental licenses, and in parts the infraction notices. The other variable that most satisfactorily explains the issuance of infraction notices in the municipalities is the use of their own website with environmental software in the environment departments.
Linear Perturbation on Axially Symmetric Vortices under A Uniform Gravity

The previous perturbative method to investigate the stability of vortex is extended so as to incorporate gravity in a uniformly rotating frame. The viscosity expansion method is employed, in which the radial and the z-components of the velocity field are proportional to viscosity and are therefore infinitesimally small, while the azimuthal component is independent of the viscosity. The rotation of the frame is incorporated by the Coriolis force. The algebraic eigenfrequency equation (EFE) of the sixth order is derived. There exist three physical eigenfrequencies that are generally coordinate dependent. The perturbations are found to be possible for the azimuthal wavenumber being equal to or greater than two. Since the real parts of the eigenfrequencies are dominantly positive and decreasing functions of the radial coordinate, the patterns of perturbations mainly form trailing spirals. Amplitudes of perturbations are also calculated. Their phases are shifted by the gravity.