Miracle-dz/UniFAR-FTUs huggingface dataset:
Microgrid Stability Analysis Considering Current State-Feedback

A converter-based microgrid including several distributed generations (DG) and energy storage systems (ESS) embodies a small power system consisting of several synchronous machines and loads. The stability issue and the coordination between generating units is an essential challenge, either in island or in grid-connected microgrids. The instability of individual DGs cause the microgrid instability as a whole. So, the individual unit stability and the microgrid stability both must be ensured simultaneously. The state feedback concept which is considered in control of converters has a substantial effect on the converter stability and microgrid stability, subsequently. This study will introduce a small-signal model for the microgrid including converter-based DGs and loads considering the previous studies in this field. A phase locked loop (PLL) is required for the control strategy. The effect of current state feedback is scrutinized and analyzed in this study as the main contribution. The effectiveness of the proposed control strategy to enhance the microgrid stability using chosen state feedback is examined through simulation studies. The simulation results ensure that the microgrid stability using the proposed control method and state-feedback is strengthened.
Oversized Waveguides as Quasioptical Antennas for Fusion Plasma Diagnostics: Scale Model Experiment

The scale model measurements of the field distribution at various distances from the aperture of antennas based on oversized quasioptical waveguides are presented. The goal is to study their characteristics for introducing radiation into the plasma chamber of thermonuclear fusion reactors. It was found that such antennas provide the necessary parameters of the microwave beam (diameter and divergence) without the use of focusing mirrors.
Dual-Band and Dual-polarization Microstrip Antennas Loaded with Split Ring Resonators

This paper is proposed a dual-band and dual-polarization microstrip antenna loaded with Split ring resonators(SRR). This antenna is combined by one 1×2 SRR and patch with corner cut. The simulated results show that circular polarization is obtained at 8.2GHz with RHCP which the axial radio bandwidths is 150MHz (8.15GHz-8.30GHz) and 9.21GHz which the impedance bandwidths is 0.57GHz (8.86GHz-9.34GHz) with Linear polarization. Further-more, the proposed antenna also possesses the advantages of low profile, easy feed and easy processing.
Detection and Recognition Simulation of Abnormal Behavior of Dynamic Systems

The problem of evaluating the emergent properties of a system and detecting and recognizing the occurrence of anomalies in the behavior of a dynamic system is formulated. To solve these problems, fuzzy cognitive modeling and a set of deep neural networks are proposed. An example of recognizing an anomaly in the behavior of processes in the airfield infrastructure is being considered.
Spatial Correlation in Single-Carrier Massive MIMO Systems

We present the analysis of a single-carrier massive MIMO system for the frequency selective Gaussian multi-user channel, in both uplink and downlink directions. We develop expressions for the achievable sum rate when there is spatial correlation among antennas at the base station. It is known that the channel matched filter precoder (CMFP) performs the best in a spatially uncorrelated downlink channel. However, we show that, in a spatially correlated downlink channel with two different correlation patterns and at high long-term average power, two other precoders have better performance. For the uplink channel, part of the equivalent noise in the channel goes away, and implementing two conventional equalizers leads to a better performance compared to the channel matched filter equalizer (CMFE). These results are verified for uniform linear and uniform planar arrays. In the latter, due to more correlation, the performance drop with a spatially correlated channel is larger, but the performance gain against channel matched filter precoder or equalizer is also bigger. In highly correlated cases, the performance can be a significant multiple of that of the channel matched filter precoder or equalizers.
Multi-Objective Genetic Algorithm for the Joint Optimization of Energy Efficiency and Rule Reduction in Software-Defined Networks

Although the use of Ternary Content-Addressable Memories (TCAMs) in the flow tables of the Software-Defined Network (SDN) switches increases the efficiency of packets matching procedure, drawbacks such as their large power consumption and the limitation on the number of flow rules that can be installed must be taken into account. This paper tackles the joint problem of power consumption and TCAM size limitation in SDN. By exploiting the Rate Adaptation technique and compression methods, a Multi-Objective Genetic Algorithm is proposed to practically solve it. Simulations on a real network topology show that our proposed solution outperforms other state-of-the-art approaches, both in terms of power saving gains (20% at non-peak TM) and maximum TCAM utilization (5%).
Avoiding RF Isolators: Reflectionless Microwave Bandpass Filtering Components for Advanced RF Front Ends

RF/microwave bandpass filters (BPFs) are fundamental components in high-frequency RF transceivers. On the transmitter side, they limit the transmitted RF signal bandwidth by suppressing out-of-band spurious signals and intermodulation products, which are primarily generated by the nonlinear active stages and can affect other RF systems. On the other hand, in the receiver, they reject out-of-band interfering/jamming signals and noise. Whereas a large variety of microwave BPFs have been proposed in the technical literature for multiple technologies (e.g., [1] and [2]), most of these BPF devices achieve their filtering functionality by means of the frequency-selective power reflection processing of the RF input signal. This means that those RF signals allocated within the operational bandwidth of the BPF are transmitted to the output terminal (with some tolerable added in-band loss and reflective-type filter, hence decreasing the mixer conversion gain.
Scheduling of Battery Energy Storage and Demand Response Resource in Balancing Ancillary Service

Nowadays, benefits and advantages of renewable energies are clear for everyone. Lower cost of these resources (in compare with non-renewable resources), global demanding for the clean energy, limitations of fossil fuel resources, and so on, increase the popularity of renewable energies in power systems. However, the main problem is that the wind and solar power as two cheapest and biggest resources of renewable energy are variable, un-dispatchable, uncontrollable. Every change in the forecasted values of these resources could disturb the balance of generation and consumption in the electricity power network, which can lead to the instability of grid. Therefore, the flexibility of network shall be increased to neutralize the fluctuations of renewable resource. The Battery Energy Storage (BES) as the trusted and reliable energy resource can play a crucial role to maintain the flexibility of grid by instantaneous response to supply and demand variations. However, some constraints of BES such as minimum charge and discharge times, capacity, rate of charge and discharge could limit the generation/consumption of this resource in the real-time balancing. This paper provides a model for scheduling of BES and shifting demand response (SDR) in balancing ancillary service to improve the flexibility of grid. SDR program is proposed as the backup resource to cover the limitations of BES and improve the flexibility of grid. The objective function of proposed model is minimizing the real-time energy supply cost. The proposed model is formulated based on mixed integer linear programming (MILP) methodology. Moreover, the performance and advantages of the proposed model are investigated via a case study.
Dynamic Augmented Kalman Filtering for Human Motion Tracking under Occlusion Using Multiple 3D Sensors

In this paper real-time human motion tracking using multiple 3D sensors has been demonstrated in a relatively large industrial robot work cell. The proposed solution extends state-of-the-art by augmenting the constant velocity model and Kalman filter with low-pass filtered velocity states. The presented method is able to handle occlusions by dynamically inclusion in the Kalman filter of only those 3D sensors which provide valid human position data. Human motion tracking was achieved at a frame rate of 20 Hz, with a typical delay of 50 ms to 100 ms and an estimation accuracy of typically 0.10 m to 0.15 m.
Evaluation of the Dynamic Structure of Turbulent Flows Using Regression Models

Results of non-stationary signal processing and interpretation using the simplest (ARX) regression model of real measurements with spaced antennas are presented. The obtained estimates of the mean velocity of the random medium travelling between ray-paths of spaced antennas coincide with those available in the literature. The considered approach makes it possible to determine the boundaries of the effective spectral interval of non-stationary signals more reasonably. This fact is critical for the task of the flow dynamical structure estimation and accurate evaluation of flows velocity. The Ideas discussed in the report may be of interest in the field of remote sensing with tools having a large-scale measuring volume allowing a diverse dynamic structure of the flows to exist inside it.
Effectiveness of PAM-4 Line Coding in Triplication-based Error Correction Codes under Harsh Electromagnetic Disturbances

In harsh electromagnetic environments, Error Detection and Correction Codes can be used to counteract transmission errors. However, the overhead introduced by Triplication-based codes can be detrimental for the communication capabilities of the system. This paper assesses if a Pulse Amplitude Modulation with 4 symbols (PAM-4) is worth using in harsh electromagnetic environments. It is found that some systems can benefit from PAM-4 in terms of availability, but a significant trade-off in terms of False Negatives must be made. A False Negative arises when the Error Detection and Correction Code deems the received data valid, whilst it was corrupted during transmission.
NDA-EVM based Co-channel Interference Analysis in Co-frequency Network

Transmission in co-frequency network always affected by co-channel interferences. In order to achieve higher communication performance, interference elimination schemes should be applied. Thus, analysis of co-channel interference in co-frequency network becomes the core issue, which offer threshold references to the designs of interference elimination and transmission mechanism. A novel method to quantify the co-channel interference based on nondata-aided error vector magnitude (NDA-EVM) was proposed in this paper. NDA-EVM was considered as a new metric to evaluate the change of the channels. Specifically, the NDA-EVM upper bound of multiple quadrature amplitude modulation (MQAM) signal under co-channel interferences is analytically derived. Theoretical analysis and simulation experiments indicate that, the derived upper bound closely matches with the theoretical one, especially at low SNR. Moreover, the time complexity of upper bound is linear order while that of theory is square order, which means it has a quicker react when channel estimating.
Anonymous Electronic Health Record Sharing Scheme Based on Decentralized Hierarchical Attribute-Based Encryption in Cloud Environment

The rapid development of communication technologies, the network, advanced computing methods and wireless medical sensors gives rise to a modern medical system. In this system, large-scale electronic health records (EHRs) are often outsourced to be stored at the third parties, such as cloud service providers (CSPs). However, CSPs are not trustworthy, that is, serious security and privacy concerns about cloud service exist because it may expose the user’s sensitive data to CSPs or unauthorized users in transmission, storage and sharing. To prevent the privacy disclosure of patients better and realize information sharing more effectively, this paper proposes an anonymous EHRs sharing scheme based on decentralized hierarchical attribute-based encryption (ABE). In the proposed scheme, (1) Multiple attribute authority (AA) ABE is leveraged to achieve fine-grained and scalable data access control and avoid bottleneck. Meanwhile, hierarchical access tree is used to encrypt multiple files in one operation, thereby saving calculation and storage load greatly. Moreover, the hidden access policy enhances user privacy protection. (2) The global identifier (GID) of a user is introduced to resist the collusion attack of users. Subsequently, an anonymous key generation mechanism is equipped to prevent multiple AAs from building a full profile using the user’s GID. (3) To ensure the correctness and integrity of EHRs, users can conduct double verification based on the verification tag and convergent key. Finally, the efficiency analysis and experiments show that the scheme meets the security requirements of key management and privacy preservation in cloud and is proven secure and efficient in practice under the decisional bilinear Diffie-Hellman (DBDH) assumption.
Functionalizing of the scaling parameter to describe subthreshold leakage phenomenon in titanium dioxide memristor

The memristor (memory resistor) is the fourth passive element of electrical circuits having dynamic resistance with the ability to keep the last level of resistance even after the power supply is interrupted. This article presents a simplified mathematical function with the capability to define the threshold conditions for memristor operation and a new pattern to describe and modeling of the unwanted current leakage in the subthreshold situation for HP TIO2 memristor. These special features provide a more realistic scheme of TIO2 memristor behavior. Our proposed mathematical function is adaptive with the majority of previous prominent works around the ionic drift modeling of HP memristor and is easy to use in SPICE simulators so can be utilized in a wide range of designs and applications. To our best known this is the first research paper in which the issue of subthreshold current leakage modeling of the memristor is addressed.
Cost-Oriented Cooperative Caching Scheme in Energy-Harvesting-Powered Ultra-Dense Networks

Caching contents at wireless edge nodes has been regarded as a promising solution for improving quality of experience (QoE) and reducing energy consumption. Integrating caching to energy-harvesting-powered (EH-powered) ultra-dense small cell networks (UD-SCNs) is an efficient way to alleviate the burdens of backhaul links and further save on-grid energy. In this paper, we propose a cooperative caching scheme which can balance two caching actions, caching the most popular contents and caching diverse contents, in EH-powered UD-SCNs. The former helps reducing transmission delay while the latter contributes to saving on-grid energy. We regard delay and energy as two types of cost and introduce a weighted cost function. Then, the caching problem is transformed to be a cost minimization problem, and a genetic algorithm (GA) is designed to solve the problem in an effective way. Numerical results demonstrate that compared with the existing cooperative caching schemes, the proposed cooperative caching scheme succeeds in balancing transmission delay reduction against on-grid energy saving.
Common-Aperture Sub-6 GHz and Millimeter-Wave 5G Antenna System

The realization of a common-aperture (or shared-aperture) 5G antenna system is proposed for compact and integrated wireless devices. As a combination of a dipole and tapered slots, an integrated antenna design, which operates at multi-bands, i.e. sub-6 GHz at 3.6 GHz and mm-wave at 28 GHz, is validated. The antenna design procedure starts with a dipole operating at 3.6 GHz, which is fed by a modified balun consisting of a tapered slot and a microstrip line. Here, the tapered slot has a dual feature, i.e., it is used to excite the dipole at 3.6 GHz and works as a tapered slot antenna at 28 GHz. Only a single feeder is optimized and used for both structures making the design unique and provides an extremely large frequency ratio. Moreover, the dipole’s arms are utilized as an antenna footprint for two tapered slot mm-wave arrays, making the dipole dual-functional. The tapered slot antenna and the mm-wave arrays are optimized in a way that the main beams point at different directions. By this configuration, the design is able to cover an angle of <inline-formula> <tex-math notation="LaTeX">$120^{o}$ </tex-math></inline-formula> of space in <inline-formula> <tex-math notation="LaTeX">$\theta -$ </tex-math></inline-formula>direction. As a proof of concept, a prototype is fabricated on Rogers RO-5880 with an overall size of <inline-formula> <tex-math notation="LaTeX">$75\times 25\times 0.254$ </tex-math></inline-formula> mm<sup>3</sup>. The simulated and measured results confirm the validity of the proposed concept.
Estimation of Oscillatory Mode Activity from PMU Measurements

We propose a method for estimating the activity of oscillatory modes in power systems. The frequencies and mode shapes of the modes of interest are assumed to be known beforehand, either from linear modal analysis or from empirical mode estimation methods, and are used in combination with measurements from Phasor Measurement Units to estimate the instantaneous mode excitation in terms of amplitude and phase. The estimation is carried out using non-linear least squares to fit a set of curves to the measured data. Combining mode shapes with measured data allows the activity to be estimated from only a low number of consecutive measurement snapshots, resulting in a problem of low computational complexity that can be solved fast enough for the method to run online.The purpose of estimating the mode activity is, firstly, to contribute to increased situational awareness and facilitate methods that build further upon this information, and secondly, to be able to synthesize signals that can serve as input to controllers for power oscillation damping. It is expected that using this excitation measure will result in a more robust controller that is less prone to disturbances and noise.
Comparative Analysis of Multiphase Topology for Energy Storage Systems

The paper presents comparison of a five-phase and a six-phase converter for charging energy storage elements - batteries and supercapacitors. The converters are structured as modules made of five or six units working on a common load. Models of five-phase and six-phase converter are made in LTSpice software. In this research a spectral analysis is performed of the load current when currents amplitude of each source changes. The comparison is made for the same output power.
A Review: Abstractive Text Summarization Techniques using NLP

Today's world is getting flooded with an increasing amount of articles and links to choose from. As this data grows, the importance of semantic density does as well. How can one say the most important things in the shortest amount of time? Having a generated summary lets one decide whether they want to deep dive further or not. Conversion of lengthy texts into short and meaningful sentences is the main idea behind text summarization. To achieve this, various algorithms are present. Machine Learning models are trained, first to understand the given document and then create a summary of it. These models achieve this task either by extracting important words out of the document or by creating human-like sentences to form the summary.
A Wireless System for Sport Assessment

In the context of sport assessment, the evaluation and monitoring of the referees decisions is of interest for several sports in order to avoid disputes and assist the referees in their activity. Some current solutions are based on video recording, third referee, etc. In this paper, a new wireless wearable system, result of the Italian research project REC-VISIO, is described suitable to assess the referees actions when they are on the move. The system is able to collect the referee staff visual perspective of a sport match, whose subjective is recorded, preprocessed and sent by a wireless network to a sideline workstation for final stabilization. The system architecture design and implementation are described along with the experimentation on the field, considering as use case a football match. The experimentation has shown the successful integration of all the different system components, where the cooperation of sensor-based subsystem, processing unit, and communication subsystem allows to collect and stabilize the video streaming reducing the effects of the movement of the referee, and send in real-time the video content to the sideline workstation without video quality degradation.
Anomaly Detection of Heat Energy Usage in District Heating Substations Using LSTM based Variational Autoencoder Combined with Physical Model

District heating systems that distribute heat through pipelines to residential and commercial buildings have been widely used in Northern Europe. The energy efficiency of district heating systems is of great interest to energy stakeholders. However, it is not uncommon that district heating systems fail to achieve the expected performance due to various faults. Identification of such rare observations that are different significantly from the majority of the meter readings data plays a vital role in system diagnose. In this study, a new hybrid approach is proposed for anomaly detection of a district heating substation, which consists of a simplified physical model and a Long Short Term Memory based Variational Autoencoder (LSTM VAE). A dataset of an anonymous substation in Sweden is used as a case study. The performance of two state of art models, LSTM and long short term memory based autoencoder (LSTM AE) are evaluated and compared with the LSTM VAE. Experimental results show that LSTM VAE outperforms the baseline models in terms of Area under receiver operating characteristic (ROC) curve (AUC) and F1 score when an optimal threshold is applied.
Modelling of Phase Distortions in Astronomical Imaging: Considering Real Conditions

Modeling astronomical images acquired through Earth atmosphere is described as a powerful research tool for developing image processing techniques. An attempt of making the model closer to real conditions is presented. Such factors like wind influence and different distortion of waves with different wavelength are modeled and compared to the case of stationary atmosphere. Also the specific of modeling the observations with an orbital instrument is explained.
A Power-Efficient Approach to Detect Mobile Threats on the Emergent Network Environment

Mobile and IoT devices are blooming, and their applications are prevailing worldwide. In the meantime, the Industry 4.0 trend converges industrial control systems with the internet environment, which makes it vulnerable. Mobile and IoT applications provide seamless connectivity to the emergent network environment for daily work. As mobile phones contain privacy information, malicious mobile applications could compromise mobile devices and cause financial losses. Moreover, attackers could launch DDoS attacks to exhaust a resource of mobile or IoT devices in the emergent network environment. Static malware analysis consumes less computing resources and power than dynamic analysis. This study proposes a power-efficient solution to identify mobile threats, which applies taint analysis to protect the emergent network environment. The experimental results show that the proposed approach could detect mobile malware efficiently.