Miracle-dz/UniFAR-FTUs huggingface dataset:
Tracking a moving sound source from a multi-rotor drone

We propose a method to track from a multi-rotor drone a moving source, such as a human speaker or an emergency whistle, whose sound is mixed with the strong ego-noise generated by rotating motors and propellers. The proposed method is independent of the specific drone and does not need pre-training nor reference signals. We first employ a time-frequency spatial filter to estimate, on short audio segments, the direction of arrival of the moving source and then we track these noisy estimations with a particle filter. We quantitatively evaluate the results using a ground-truth trajectory of the sound source obtained with an on-board camera and compare the performance of the proposed method with baseline solutions.
A Multisegment Electro-Active Polymer Based Milli-Continuum Soft Robots

This paper presents the design, modeling and fabrication of a millimeter-size Continuum Soft Robot (CSR). The robot consists of active flexible polymer actuator-based multisegment robot. A multiphysics model based on multilayer cantilever for large displacement is established between the input voltages to the distal tip position of a single segment robot. The extension of the model to multisegment CSR is derived. The proposed model is validated experimentally then a two-segment CSR and three-segment CSR in 3D arrangement are investigated, demonstrating the model efficiency for obtaining complex configuration. Moreover, various configurations can be explored to derive complex kinematics then increasing the robot capability.
Web-Based Application for Analysis of Electrical Circuits and Systems

This paper presents web-based graphical schematic editor for analysis of electric and electronic circuits. Continuous-time linear and nonlinear circuits as well as periodically switched linear circuits can be analysed in this editor. In case of linear circuits, results can be obtained in symbolic form. The editor uses Spice OPUS and Maple software with PraCAn package as a computation engine. All circuits created in this editor can be turned into functional blocks that can be subsequently edited through programming code. The editor contains a model of ideal, linear and nonlinear operational amplifier. The whole system is developed at the Department of Circuit Theory, for engineering education and research support.
Comparison of Active and Passive Balancing by a Long Term Test Including a Post-Mortem Analysis of all Single Battery Cells

Due to the fact, that there are basically no practical test comparisons between active and passive lithium-ion battery balancing systems, a long term test is carried out. Therefore two batteries with an active and a passive balancing system are cycled. After about 2600 cycles test is stopped to start with further investigations. Capacity decrease and the increase of internal resistance of the two used battery packs are presented. To investigate the influence of load cycles in combination with different battery management systems (BMS) a detailed single cell investigation is executed. Finally, active balancing increases the usable capacity by a maximum of 2% compared to passive balancing and reduces the cell to cell deviation of capacity and internal resistance. Furthermore it is shown that the additional stress due to frequent energy redistribution in active balancing systems has no negative ageing effects to the cells compared to passive balancing.
Combining VM Preemption Schemes to Improve Vertical Memory Elasticity Scheduling in Clouds

Server consolidation and resource elasticity are among two of the most important resource management features in cloud and edge computing. One of two forms of elasticity is often adopted. While horizontal elasticity is concerned with the acquisition and release of computational nodes in accordance with demand, vertical elasticity focuses on the distribution of a node's resources among its hosted virtual machines (VMs) or containers, by adjusting the capacity of the resource types allocated to each individual VM in accordance with its respective application's needs. In the case of vertical elasticity, when insufficient resources are available to allocate to a given VM, its application's performance may suffer degradation. For online applications, the only alternative is to live-migrate the VM to another server. On the other hand, when running batch jobs, the resource-constrained VM could also be suspended or saved to disk and revived elsewhere or on the same host, when resources become available. Given that memory availability has a significant influence on performance and system throughput, this paper investigates the viability of integrating VM migration, pausing and suspension schemes as part of a VM scheduling strategy to support the execution of both online and batch applications in a virtualized infrastructure employing memory elasticity. Results show that combining such schemes can provide utilization benefits for cloud service providers when memory is scarce.
Design and Implementation of a Dual Frequency and Bidirectional Phase Gradient Metasurface for Beam Convergence

A phase gradient metasurface (PGM) array with beam converge characteristic in reflection direction at 15 GHz and transmission direction at 5.6 GHz is proposed in this letter. Compared with the traditional unidirectional PGM, the proposed PGM can achieve bidirectional radiation at two frequencies. A horn is used as the feed placing at a focal length of 200 mm of PGM array. Simulation results show that the horn has a peak gain enhancement of 11.9 dB at 15 GHz with a –3 dB beamwidth reduction of 33° in reflection direction and a peak gain enhancement of 7.9 dB at 5.6 GHz with a –3 dB beamwidth reduction of 30° in transmission direction. The proposed PGM array achieves a beam convergence in two directions at two different frequencies and has a potential use for communication system consisting of receivers with multifrequency and multilocation characteristic.
Vertical Coaxial-to-Ridge Waveguide Transitions for Ridge and Ridge Gap Waveguides With 4:1 Bandwidth

An ultra-wideband vertical coaxial-to-single-ridge waveguide transition is designed to cover Ku-, K-, and Ka-bands simultaneously. The simulated and measured back-to-back transitions have achieved better than 15-dB return loss within 12.8–40 GHz. The transition can also be a direct transition to the ridge gap waveguide (RGW). In addition, a similar concept is used to design a wideband coaxial-to-double-ridge waveguide transition to feed symmetric and asymmetric double ridge waveguide on a bandwidth ratio of more than 4:1. These transitions will be used to feed broadband ridge and RGW power splitters.
Complementary Color Wavelet: A Novel Tool for the Color Image/Video Analysis and Processing

In human vision, it has been well understood that the red, green, and blue (RGB) trichromatic system, whose colors can be well expressed by an RGB hue ring with complementary color relations, is the most accessible and extensible color representation. However, such color relations rarely play a role in color image/video processing tools such as wavelets. In this paper, the gap between wavelets and complementary color relations is filled by designing a novel color image/video processing tool called the complementary color wavelet transform. Our novel wavelets consist of a family of well-designed 2-D complex wavelets with $2\pi /3$ phase differences copied from the R, G, and B angle relations on the RGB hue ring. Analyses show that our new wavelets can not only utilize the complementary color relations but also inherit and improve upon the advantages of classical complex wavelets, such as their multi-resolution, directional selectivity, and shift-invariance properties. By the newly designed wavelets and by properly adding and/or subtracting the wavelet coefficients of a color image/video, some color-related image/video processing applications that are typically seen as infeasible or difficult to achieve by traditional methods, for instance, capturing and classifying local color changes, statistical modeling of the wavelet coefficients among the color channels, and multi-resolution directional color filtering, can be performed very easily. The cost for this is simply a transform redundancy increase (2.25 times that of classical complex wavelets). We provide three application examples of our method: color filtering, texture retrieval, and video quality assessment. The results show that our new wavelet tool greatly outperforms traditional methods.
A Hierarchical Self-Adaptive Data-Analytics Method for Real-Time Power System Short-Term Voltage Stability Assessment

As one of the most complex and largest dynamic industrial systems, a modern power grid envisages the wide-area measurement protection and control (WAMPAC) system as the grid sensing backbone to enhance security, reliability, and resiliency. However, based on the massive wide-area measurement data, how to realize real-time short-term voltage stability (STVS) assessment is an essential yet challenging problem. This paper proposes a hierarchical and self-adaptive data-analytics method for real-time STVS assessment covering both the voltage instability and the fault-induced delayed voltage recovery phenomenon. Based on a strategically designed ensemble-based randomized learning model, the STVS assessment is achieved sequentially and self-adaptively. Besides, the assessment accuracy and the earliness are simultaneously optimized through the multiobjective programming. The proposed method has been tested on a benchmark power system, and its exceptional assessment accuracy, speed, and comprehensiveness are demonstrated by comparing with existing methods.
Robust LIDAR Localization for Autonomous Driving in Rain

This paper introduces a map-based localization method aiming to increase robustness in rainy conditions. This method utilizes two types of features: ground reflectivity features and vertical features extracted from 3D LIDAR scans and builds vehicle pose belief with two filters: a histogram filter and a particle filter. The posterior distributions from the two filters are integrated to estimate vehicle poses. This method exploits advantages of both features and filters, compensating respective weakness to deal with complex urban environments. Testing was performed in the fair and rainy weather. Road test results prove robustness and reliability of the proposed method.
Modification of Lab color model for minimizing blue-green illumination of underwater vision system

Deep underwater images suffer from low contrast and blue-green illumination which leads towards restriction to the visibility of the objects. Most of the previous proposed enhancement techniques for underwater vision system applications improve the image contrast but blue-green illumination retains in the images. This paper discusses the improvement of underwater image contrast with concentration in modification of Lab color model. The modification of Lab color element in this color model based on shifting the entire pixels of the image to another shifting values, in which, the new shifted values exhibit an improvement in terms of image contrast and minimizing blue-green illumination based on optimal information in the image. The proposed method integrates two main steps, namely dark-stretched image fusion (DSF) and pixel distribution shifting (PDS). In DSF step, dark channel image is stretched, divided into two channels before it is fused together. Next, the image pixel distribution in Lab color model is shifted towards more natural view based on human visual system. Qualitative evaluation indicates a significant improvement of image contrast in output images.
A Testbed Evaluation for a Privacy-Aware Monitoring System in Smart Home

An ambient assisted living system can help people improve residents' quality of lives in their homes while managing the energy resources more efficiently using wireless portable monitoring systems. The key challenges for such monitoring systems are scarce energy and privacy concerns. This paper reports an experimental study to evaluate a threshold-based monitoring method for temperature and light sensing to reduce energy consumption of the sensor nodes which increases the lifetime of the monitoring system. We have implemented a testbed using PIR sensors to monitor the behaviour of a single resident house considering the willingness for independent living in senior citizens. The overall results and analysis of our testbed shows more than 90% reduction in the number of transmitted packets which have increased the lifetime of ambient monitoring system. Furthermore, the AES encryption algorithm is selected to be implemented in our smart home testbed to evaluate the confidentiality of collected data.
A Queueing Network Model for Analysis of Patient Transitions Within Hospitals

Safe and efficient patient transitions are of critical importance to ensure patient safety and care quality. To study patient transitions, this paper presents a queueing network model-based iteration method to model and analyze transitions between emergency department, intensive care unit, and general ward within a hospital. Routings with feedback flows are considered under general arrival and service processes, and the effects of blocking on performance measures are presented for both the mean and variability. It is shown that the iteration procedure is convergent and leads to acceptable accuracy of estimation, for both small- and large-sized hospitals. In addition, the impacts of bed capacity, admission rate, as well as arrival and service time variabilities are discussed. Such a method provides an efficient way to study patient transitions within hospitals. Note to Practitioners—Many critical and complex problems occur at the interfaces of healthcare delivery systems. Within hospitals, transitions occur when patients are transferred between units such as emergency department, intensive care unit, and general ward. Although numerous studies on patient transitions have been carried out, most of them only focus on a single unit or transition without recognizing the importance of coordination among multiple units. However, understanding the complete patient flow throughout the hospital is crucial for hospital administrators in predicting the expected demand and planning resources appropriately. Thus, a quantitative model to study the transitions within the hospital by taking into account the interactions among all the involved departments is needed. In this paper, we present a queueing network model to evaluate patient transitions within hospitals. An iterative method is used to analyze transitions encompassing multiple departments. It is shown that such a method can result in close estimates of transition behavior and provide managerial insights to improve system performance. Moreover, the method is computationally efficient that it can be used to study very large-sized hospitals.
Leader–Follower Formation Control of USVs With Prescribed Performance and Collision Avoidance

This paper addresses a decentralized leader–follower formation control problem for a group of fully actuated unmanned surface vehicles with prescribed performance and collision avoidance. The vehicles are subject to time-varying external disturbances, and the vehicle dynamics include both parametric uncertainties and uncertain nonlinear functions. The control objective is to make each vehicle follow its reference trajectory and avoid collision between each vehicle and its leader. We consider prescribed performance constraints, including transient and steady-state performance constraints, on formation tracking errors. In the kinematic design, we introduce the dynamic surface control technique to avoid the use of vehicle's acceleration. To compensate for the uncertainties and disturbances, we apply an adaptive control technique to estimate the uncertain parameters including the upper bounds of the disturbances and present neural network approximators to estimate uncertain nonlinear dynamics. Consequently, we design a decentralized adaptive formation controller that ensures uniformly ultimate boundedness of the closed-loop system with prescribed performance and avoids collision between each vehicle and its leader. Simulation results illustrate the effectiveness of the decentralized formation controller.
Discriminative Robust Gaze Estimation Using Kernel-DMCCA Fusion

The proposed framework employs discriminative analysis for gaze estimation using kernel discriminative multiple canonical correlation analysis (K-DMCCA), which represents different feature vectors that account for variations of head pose, illumination and occlusion. The feature extraction component of the framework includes spatial indexing, statistical and geometrical elements. Gaze estimation is constructed by feature aggregation and transforming features into a higher dimensional space using the RBF kernel ���� and spread factor. The output of fused features through K-DMCCA is robust to illumination, occlusion and is calibration free. Our algorithm is validated on MPII, CAVE, ACS and EYEDIAP datasets. The two main contributions of the framework are the following: Enhancing the performance of DMCCA with the kernel and introducing quadtree as an iris region descriptor. Spatial indexing using quadtree is a robust method for detecting which quadrant the iris is situated, detecting the iris boundary and it is inclusive of statistical and geometrical indexing that are calibration free. Our method achieved an accurate gaze estimation of 4. 8º using Cave, 4.6° using MPII, 5. 1º using ACS and 5.9° using EYEDIAP datasets respectively. The proposed framework provides insight into the methodology of multi-feature fusion for gaze estimation.
Development of A Small Clamper for Tendon-sheath Artificial Muscle

Many artificial muscles have been reported in recent years, in addition to the most popular pneumatic artificial muscles, there are many other artificial muscles that based on smart materials or composite materials. Artificial muscles usually have compliant structure, light weight, or high power-to-weight ratio. However, they also expose many defects that caused by their structure or material, moreover they are not developed in line with muscle mechanics. Therefore, based on Hill muscle model, we proposed a novel tendon-sheath artificial muscle with slender structure and light weight, it can meet the requirements of robotic applications like exoskeleton. Moreover, a small clamper driven by electromagnet is developed in this paper for the switching control of muscle activation and inactivation. The clamper is designed for clamping wire rope with diameter of 1-2mm which refers to the inner tendon of the tendon-sheath mechanism, and the maximum clamping force is 800N. The clamping performance of the clamper was tested on an experiment platform. The experimental results illustrated that the small clamper can clamp the moving wire rope effectively. On average, it takes 230ms for the small clamper from receiving the control signal to starting clamping, and another 150ms is taken for fully clamping.
Image Boundary Extension With Mean Value for Cosine–Sine Modulated Lapped/Block Transforms

We present a novel image boundary extension and mean value extension (MVE) for directional lapped transforms, particularly cosine–sine modulated lapped transforms (CSMLTs). Lapped transforms are usually used with an extension technique, such as periodic extension (PE) or symmetric extension (SE), for nonexpansive convolution at signal boundaries. When directional textures (oblique lines and curves) appear at the 2D signal (image) boundaries, both PE and SE produce directional discontinuities, which degrade the sparsity of the transformed coefficients, especially in the case of directional lapped transforms. MVE reduces the discontinuities for directional textures better than PE or SE do; it thus improves the efficiency of the sparse representation based on directional lapped transforms. Moreover, to reduce computational costs compared with those of directional lapped transforms, we introduce new directional block transforms called cosine–sine modulated block transforms. These new transforms are derived from a minimum tile processing (tiling) of <inline-formula> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula>-band CSMLTs with <inline-formula> <tex-math notation="LaTeX">$2M$ </tex-math></inline-formula> filter lengths and nonexpansive convolutions. The resulting directional block transforms, particularly in the case of the MVE, have richer directional selectivity and have better performance compared with a discrete Fourier transform as shown in experiments.
Substrate Integrated Waveguide Filtering Rat-Race Coupler Based on Orthogonal Degenerate Modes

In this paper, a method for designing substrate integrated waveguide (SIW) filtering rat-race couplers based on TE102 and TE201 orthogonal degenerate modes is proposed for the first time. Without additional circuits, the desired 0° and 180° phase differences of the rat-race coupler are realized by the inherent in-phase and out-of-phase characteristics of E-fields at TE102 and TE201 modes. E-field distributions of the SIW cavities at TE102 and TE201 modes are studied for guiding the circuit realization. By properly arranging the locations of input–output ports and coupling regions in the SIW cavities, magnitude and phase properties of the rat-race coupler topology are realized. And then the filtering responses can be integrated with the rat-race coupler. A detailed design method based on coupling matrix is presented. A filtering rat-race coupler is implemented using square SIW cavities to verify the proposed method, showing good performance of filtering responses, amplitude balance, as well as 0° and 180° phase differences. For further verification, another filtering rat-race coupler is fabricated using two circular SIW cavities to simplify the structure. Comparison with other filtering couplers indicates that the proposed designs exhibit the advantages of good filtering responses, relatively high Q factor of the entire filtering circuits, and simple structure.
Enhanced Non-Steady Gliding Performance of the MultiMo-Bat through Optimal Airfoil Configuration and Control Strategy

Many robots make use of gravitational potential energy, generated by another mode, to enhance mobility through gliding locomotion. However, unstructured environments can create situations in which the initial conditions for steady-state gliding cannot be achieved; for example, jumping out of a hole, where the obstacle is very close to the robot. This paper suggests an optimization methodology for finding airfoil configurations and control strategies to maximize the effective non-steady-state gliding ratio for the most challenging initial condition, that of zero velocity. Parameters for the optimization are a location of a robot's center-of-mass in relation to its center-of-pressure and, through the addition of a tail, an active pitch control strategy. The optimal center-of-mass location produces the best passive gliding performance (morphological intelligence), and the optimal control strategy improves the gliding distance. Due to the aerodynamic complexities of modeling the collapsible airfoils, we find the optimal location of the center-of-mass from gliding experiments performed on the robot at different center-of-mass locations and initial pitch angles. An optimal location of the center-of-mass was found to be 40% of the wing chord for our robotic platform; measured from the wing's leading edge. The optimal location has a wide range of initial pitch angles which result in stable, yet non-steady-state, gliding behaviors. The morphological intelligence built into our robotic platform creates two observable dynamic behaviors, that of horizontal velocity gain and sink rate minimization. We then estimate the drag coefficients from the experiments, and conduct dynamic simulations to optimize the pitch control strategy. The design methodology presented here can enhance the non-steady-state gliding performance of a broad range of gliding robots, and the control strategy can further enhance performance on those which utilize an active tail.