Miracle-dz/UniFAR-FTUs huggingface dataset:
Application of Non-Negative Tensor Factorization for Airport Flight Delay Pattern Recognition

With the rapid development of civil aviation transportation in China, huge demand growth has broken the balance between supply and demand, resulting in airspace congestion and increasing flight delays. The delays of large airports have been increasing year by year, which has seriously affected the air travel experience of passengers. Obtaining their flight delay patterns can help identify defects in flight scheduling and airspace utilization. The investigation based on the actual flight operation data of Tianjin Binhai International Airport (TSN) is conducted, in order to capture the relationship and impact between the factors such as traffic flow direction, airline attributes and hourly average delay distribution. Furthermore, Non-negative Tensor Factorization (NTF) is applied to pattern recognition by introducing CP (CANDECOMP/PARAFAC) decomposition and Block Coordinate Descent (BCD) algorithm for selected data set. Numerical experiments show that the designed method has good performance in terms of computation speed and solution quality. Recognition results indicate the significant pattern characteristics of the Tianjin airport delay are extracted, which can provide some new perspectives for air traffic management unit to alleviate airspace congestion and improve service quality.
AC series arc fault detection with stacked autoencoders

Series arc fault can occur in domestic electrical networks and lead to fire accidents. Many conventional detection algorithms based on time or frequency analysis have been published. Recently, machine learning technics have been adapted to the arc fault detection task and give promising results. However, the use of machine learning is frequently limited to the classification part. Manual feature extraction part which requires time and effort is always needed before obtaining the optimized features. In this paper, we used stacked autoencoders to replace the feature extraction part. The method presented can distinguish normal state and series arc fault with good accuracies.
A Markerless Gestural Interface for Avatar Control

This project serves as a gestural interface for searching a motion capture database. This system is intended to handle the gestures of a wide range of users employing algorithms that were trained on gestures identified in a user study. With this system, users can act out gestures in front of a natural interaction device, which will trigger different behaviors of an on-screen character. This inexpensive system captures movements using a Microsoft Kinect or similar sensor. A blob tracking method is used in conjunction with hidden Markov models (HMMs) to recognize the motions to be retrieved from a motion capture database and performed by an on-screen avatar.
Integrated Virtual Voltage Vectors and Duty Cycle Control to Minimize the Current Ripples in Finite Control Set Model Predictive Control for Permanent Magnet Synchronous Motor Drives

Finite Control Set Model Predictive Control (FCSMPC) is widely acknowledged as a simple and effective control scheme for permanent magnet synchronous motor (PMSM) drives. It delivers the merit of quick dynamic response however faces problems such as large current ripples and unsatisfactory steady state performance. This paper proposes a FCSMPC method which minimizes the current ripples by integrating the concept of duty cycle and virtual voltage vectors. In the proposed method, six symmetrically positioned virtual voltage vectors are introduced in addition to the six original active voltage vectors to expand the finite control set, among which one optimal vector is selected and applied in each sampling interval according to the enumeration-based principle of cost function minimization. Then, the duration of the optimal vector is decided by an efficiently calculated duty ratio. Compared to the conventional FCSMPC, the proposed method causes no additional computation burden but exhibits much lower current ripples. The proposed method is experimentally compared with two typical FCSMPC methods for an interior permanent magnet synchronous machine and it is proved that the proposed method delivers better steady-state performance while maintaining quick dynamic response.
Evaluation of an equine therapy program in students with Autism spectrum disorder

Equine Assisted Therapy (EAT) has the main objective of using horseback riding as a tool in a therapeutic process to improve, among other facets, motor skills and postural control and even psychological well-being. The purpose of this research was to determine if equinetherapy (horseback riding with a therapeutic aim) favours the motor, communication and social development in subjects with ASD. A case study was performed with 5 subjects between 8 and 31 years. The program was carried out over 32 sessions of 60 minutes each, a day a week. The recording techniques were a questionnaire, observation and a field diary. Among the most salient results, we point out improvements in balance, posture, fine and gross motricity, and an optimal muscle relaxation that gradually leads to a removal of stereotypies. Regarding the aspect of social communication, a major improvement in non-verbal communication, and new bonding of friendship, love and respect for animals. This study is a contribution to the scientific evaluation of equine therapy as an effective treatment in persons with ASD.
Influence of Arcing Contacts Erosion on Decomposition Products under Arc Discharge in SF6 Circuit Breaker

SF6 is widely used in circuit breakers for rated voltage of 40.5kV and above due to its excellent insulation and arc-quenching performance. Decomposed components analysis (DCA) method is considered one of the most promising methods for the condition monitoring and fault diagnosis of SF6 circuit breaker. The arcing contacts must be eroded by high temperature electric arc when the circuit breaker interrupts current, which has a significant influence on SF6 decomposition products. In this paper, the influence of arcing contacts erosion on SF6 decomposition products was studied. The experiments were carried out on a 40.5kV SF6 circuit breaker. The gas chromatograph and electrochemical sensor were used to analysis the decomposition products. It has been found that the concentration of decomposition products increases with the arc energy. The arcing contacts erosion has a significant effect on the concentration of SO2, SOF2, CO2 and CS2. Comparing with the state before contacts erosion, the concentration of SO2+SOF2 has decreased significantly. The concentration of CS2 has increased, and the concentration of CO2 has increased rapidly. The main reason for the change of decomposition products concentration before and after contacts erosion is discussed. The research results can provide the effective basis for the condition evaluation and fault diagnosis of SF6 circuit breakers.
Golay-Encoded Pulse-Inversion Subtraction for Real-Time Ultrasound Monitoring of HIFU Therapy

Ultrasound (US) imaging is often used for guidance of high-intensity focused ultrasound (HIFU) treatment due to its high temporal resolution and low cost. However, real-time US monitoring is often hindered when the strong HIFU interference overwhelms the imaging echoes. In this study, a method of Golay-encoded pulse-inversion subtraction (PIS) is proposed to better visualize the change of imaged object during the HIFU treatment. It effectively eliminates HIFU interference patterns in real-time US imaging and also improves the signal-to-interference ratio (SIR). In PIS method, the received imaging echo of positive transmit is subtracted from that of negative transmit to cancel the HIFU component. When Golay excitation is adopted, imaging echo after PIS is further decoded by matched filters for pulse compression. The performance of the proposed method was evaluated through experiments with both PVA phantom and ex-vivo swine liver. Results show that 4-bit Golay transmit can improve the SIR from -15.0 dB of un-coded transmit to 3.5 dB. With PIS, the SIR of 4-bit Golay further increases to 15.9 dB.
Comparative Evaluation of Simplified and Complex IPM Machine Models on Control Development for Traction Applications

The paper presents a comparative evaluation of simplified and complex interior permanent magnet (IPM) machine models for control development in traction applications. It is shown that although control implementation using the complex model could result in better IPM machine performances, in practice, validation of complex model is significantly complicated and deviations from assumed parameters may compromise the performance of the control scheme. It is demonstrated that the simplified model of which validation is simpler may provide similar performance compared with the complex model. Thus, the simplified model-based control method can be considered for traction applications at the earlier stage of control development or when validation of the complex machine model is difficult.
Artificial-Noise Aided Precoding Design for MIMO Integrated Radar and Communication Systems

Integrated radar and communication (IRC) systems are promising in the next generation wireless communication networks. However, to realize high level security of information transmission in IRC systems is challenging due to the large transmission power and the open unguided nature of the wireless channels. In this paper, the secure precoding and artificial noise (AN) techniques are investigated to improve the secrecy rate of a multiple-input multiple-output IRC system with multiple eavesdroppers. The formulated secrecy rate maximization problem is non-convex due to the logarithmic of the determinant that exists in the objective function. Instead of using Taylor series approximation of the non-convex elements, we propose to linearize two log-det terms to tackle this challenging problem. After linearization, an alternating optimization algorithm is proposed to solve the primitive problem. Moreover, a first-order approximation is employed to handle the quadratic constraint on radar detection performance. The suboptimal secure precoding and AN scheme can be obtained for maximizing the information security transmission rate of the legitimate receiver while ensuring the performance of radar detection. Simulation results are presented to validate the performance of our proposed design.
Enhanced Internal Permanent-Magnet Machines Flux Weakening Control Strategies for Traction Applications

This paper deals with the optimization of the control strategy of internal permanent-magnet synchronous motor for light vehicle application. In particular this work proposes different control strategies to address the critical issue of fast torque transition, presenting different modified flux-weakening strategies based on outer voltage loop or id current error. The proposed modified control strategies are experimental validated with an extensive test champagne on a dedicated test bed.
Implementation Guidelines for the Optimal-Sampling-inspired Self-Triggered Control

In a self-triggered scenario the controller is allowed to choose when the next sampling time should occur and which control action will be maintained until that happens. This emerging control type is aimed at decreasing the use of computational resources (processor and network) while preserving the same performance control as the one obtained via a controller with periodic sampling. Within this framework it has been developed recently a self-triggered control technique inspired by a sampling pattern whose optimal density minimizes the control cost; this approach is called ”optimal-sampling inspired self-triggered control”. However the strategies used to implement it on real microprocessor-controlled systems working under disturbances are still unclear, then this paper addresses some implementation guidelines to make this theory applicable to actual controllers. The proposed solution comprises a new conception of this technique based on a closed-loop observer as well as making strategies for implementation of computationally expensive processes by lightweight polynomials fitted at design stage. Simulations and practical experiments confirm the solution is effective and there could be an open research topic concerning observation in optimal-sampling self-triggered control techniques.
User-Coupling Angle-Domain Adaptive Filtering based Multiuser MIMO Frequency Synchronization

In this paper, we develop a user-coupling angle-domain adaptive filtering (UC-ADAF) based frequency synchronization method for the uplink of a massive multiple-input multiple-output (MIMO) multiuser network, in the presence of highly overlapping angle-of-arrival (AoA) regions among coexisting users. In order to deal with the extremely severe multiuser interference (MUI) among users with highly overlapping AoA region, we propose to couple them together and perform joint carrier frequency offset (CFO) estimation and data detection. For the coupled users, the UC angle-constraining matrix (UC-ACM) can inherently suppress the interference from non-overlapping users and the UC-ADAF vectors are adaptively optimized to further eliminate the MUI from slightly overlapping users. Moreover, the challenging problem of addressing the severe MUI caused by the highly overlapping users is circumvented through joint estimation and detection. The effectiveness of the proposed UC-ADAF approach and its superiority over the existing methods, are demonstrated by numerical results.
Self-Balanced Operation of a Standalone PUC5 Multilevel Inverter Based on its Averaged Model

Compared to other multilevel inverter (MLI) topologies, the Packed U -Cells (PUC) inverter is capable of generating more levels with less components. Thus, this paper investigates the operation of a 5-level PUC (PUC5) inverter supplying an RL load in both open-loop and closed-loop operations based on its averaged dynamical model. The aim is to prove that the self-balancing, a natural feature of the converter, could be obtained by the selection of a regular phase-shift between two carrier signals when applying a Pulse Width Modulation (PWM) technique. Moreover, a nonlinear feedback scheme is proposed to ensure fast balancing of the capacitor voltage and good tracking of the output voltage reference. Simulations results are presented to show the performance of the proposed techniques in ensuring self-balancing of the capacitor voltage and high tracking quality of the desired values.
Output Impedance Modelling and Sensitivity Study of Grid-Feeding Inverters with Dual Current Control

In this paper, the output impedance of a three-phase inverter based on a dual current control (also called double synchronous reference frame current control) is modelled, which includes: the current loop gain, the control delay, and the Phase-Locked Loop (PLL). The impact of these parameters on the impedance is then analysed by a sensitivity study. The model is derived using transfer matrices and complex transfer functions, and it results in a compact impedance formulation that can be used in harmonic small-signal stability studies and system-wide steady-state harmonic calculations.
Multi-plane-transmit (MPT) Volumetric Imaging based on A Matrix Array: Experimental Validation

Multi-plane-transmit (MPT) is a matrix array based 3D beamforming methodology, which combines the features of diverging wave compounding (DWC) and multi-line-transmit (MLT). The MPT beams are diverging in one lateral dimension, while focused in the other lateral dimension, leading to a plane-wise reconstruction process. As a result, compounding is performed within the beam planes, while parallel transmit scanning is performed across the planes. In our previous work, computer simulations have proved that the proposed MPT setup outperforms 3D DWC and 3D MLT at a similar frame rate particularly for moving targets such as the heart. In this work, the first experimental validation experiments are conducted on a standard phantom to further investigate the performance of MPT. The experimental results show that the proposed MPT setup has better contrast ratio (CR) and contrast-to-noise ratio (CNR) when compared with 5 ◊ 5 DWC, while frame rate is similar. Furthermore, the performance of different MPT setups was also investigated. These preliminary phantom experiments demonstrate the advantages of MPT beamforming.
Joint analysis of verbal and nonverbal interactions in collaborative E-learning

We present here some preliminary analysis of audio-video interactions involving two groups of learners performing collaborative learning tasks. Living in two different countries, their mental representations are different and produce what we called a clash of contexts (“socio-cognitive misunderstanding”). The verbal dimension of the video was annotated by experts. The nonverbal, affective, dimension was tagged automatically. We found an interesting correlation between verbal and affective channels. Particularly, on both side, a kind of “Eureka effect” was detected as a key moment when learners understand each other and when their emotion changes, from frustration to happiness.
Fog-Enabled Cooperative Offloading for Intermittently Connected Vehicular Networks

In this paper, we investigate how to utilize the surplus resources in intermittently connected vehicular networks (ICVNs) to help target vehicles downloading and processing files from remote server. To this end, we propose a fog-enabled scheme for ICVNs to make the pooled resources distributed among moving vehicles work cooperatively. Specifically, each target vehicle is served by a virtual mobile fog node whose resources are extracted from a set of supporting vehicles coming from the opposite direction. The corresponding supporting vehicles instead of the target one download chunks of raw data from the remote server and pre-process them respectively. The pre-processed data are further carried on by the supporting vehicle and transferred to the target until they encounter. Considering the V2V communication interference as well as the computing and storage capability constraints of each supporting vehicles, we formulate the offloading problem as a mixed integer programming problem which minimize the average time cost of target vehicles receiving entire processed data. Since the problem is NP-hard, we design a heuristic algorithm to schedule the resource pool to help target vehicles. The simulation results confirmed the effectiveness of our algorithm in reducing the time cost. Furthermore, the proposal is more robust in different file sizes compared with choosing supporting vehicles by encounter order.
Low Frequency Ripple Removal Method for LLC Converter Based on Quasi-PIR Controller

LLC resonant converter has been widely used in DC-DC converters because of its high efficiency characteristic. However, the output voltage will be accompanied by 120 Hz ripple when the DC input is supplied by an uncontrolled diode rectifier in the 60 Hz grid. In order to remove the double frequency voltage ripple, the quasi-resonant controller is used in this paper, which inherits the advantages of the resonant controller. And the quasi-PI-resonant (quasi-PIR) controller is designed to eliminate AC ripple and keep the output voltage constant. The converter system with the quasi-PIR controller is investigated and compared with traditional PI controller. Experimental results on a 300 W LLC converter are provided. The experimental results show that with 10 V RMS 120 Hz AC voltage at the input of 400 V, the 120 Hz ripple at the output is reduced from 380 mV to 22.5 mV using the quasi-PIR controller instead of the PI controller.
Robust Analysis of Biped Walking on Uneven Terrain Using Output Zeroing Control with Trajectory Optimization

Biped robots are expected to have various activities in human society, and many biped robots have been developed. As the example, limit cycle walkers, can realize efficient walking using their own dynamics. However, they have a problem of weak robustness on uneven terrains. On the other hand, a technique for improving robustness by using output zeroing control with relative degree 3 has been proposed. In this paper, we derive the reference trajectory for the output function and holonomic constraints used when applying output zeroing control with relative degree 3 by direct collocation method which is a method of a trajectory optimization. We show that they walk by using the derived reference output function and holonomic constraints and improve the robustness on uneven terrain.
Mitigation of Strong Background Radiation with Attenuation Diversity for Vehicular Visible Light Communication

Orthogonal frequency division multiplexing (OFD-M)based outdoor visible light communication (VLC)technology has a broad prospect in the future intelligent transportation systems (ITSs), but it's prone to the problem of receiving signal saturation distortion. So we proposed a receiver architecture with an adjustable attenuator to mitigate the saturation distortion caused by strong solar irradiance in a commercial avalanche photodiode (APD)module. The simulation results show that the proposed receiver architecture has a good performance in the outdoor VLC system for both asymmetrically clipped optical OFDM (ACO-OFDM)modulation and direct current-biased optical OFDM (DCO-OFDM)modulation. Experimental results show that the proposed scheme has excellent performance in practical systems while utilizing DCO-OFDM modulation, and the bit error rate (BER)is reduced from 0.3 to 10−3under strong background light interference, which verified the feasibility of our proposed receiver architecture.
Sensitivity of Dynamic Resistance of Gas Circuit Breakers to the Arc-induced Contact Erosion

Dynamic resistance measurement (DRM) is utilized as a non-invasive method to assess the condition of arc contacts in high voltage gas circuit breakers. The main objective of this study is to determine how sensitive the dynamic resistance of a gas circuit breaker is to the contact erosion caused by arcing in gas circuit breakers. For this purpose, short-circuit current interruption experiments have been performed on a puffer type 24 kV SF6 circuit breaker. The results show that the contact erosion does not occur uniformly on the surface of contacts, therefore until the whole surface is not eroded, the DRM is not able to detect any arc contact length variation. However, the amplitude of average arc contact resistance is in agreement with the amount of erosion.
Model Predictive Control of Four Level NNPC DSTATCOM for Power Quality Improvement in Distribution System

Two level Voltage Source Inverters (VSI) are the viable solution for Distribution Static Compensator (DSTATCOM) applications in secondary distribution system, where the voltage levels are either 415 V or 230 V. However, the limitations of two level VSIs in primary distribution system (3.3 kV - 33 kV) are the requirement of higher rating switches or series connection of lower rating switches, which motivates the replacement two level VSIs with multi-level inverters (MLI). Therefore, in this paper Model Predictive Control (MPC) of four level Nested Neutral Point Clamped (NNPC) MLI based DSTATCOM is proposed. In the proposed work cost function is framed as a combination of DSTATCOM currents and capacitor voltages which can compensate the current related power quality issues as well as eliminate the requirement of additional PI controllers for voltage regulation of flying capacitors. Weighting factors Tuning during multi constraint case is a tedious task. To overcome this limitation, a Multi-Criteria Decision Making (MCDM) method namely simple additive weighting method is used in the proposed work which reduces the difficulties in the weighting factor tuning. The performance of the proposed control algorithm is evaluated using simulation which shows the efficacy of the proposed control algorithm.