Miracle-dz/UniFAR-FTUs huggingface dataset:
Filtering Components by Using Dielectric Waveguide Resonators

Dielectric waveguide resonator (DWR) owns merits, such as high quality factor, high power capacity, compact size, and light weight, and has been a popular selection in the 5th generation (5G) communication systems. This paper gives a review of the recent works in the authors’ research group on filtering components by using the DWRs, e.g. bandpass filters, a switching bandpass filter and a diplexer. The designed filtering components owns low loss, good return loss, compact size, and light weight, simultaneously.
Efficient Recursive Convolution Schemes for the Accurate FDTD Modeling of Graphene Interband Contribution via Complex Conjugate Pairs

The accurate time-domain numerical modeling of graphene surface conductivity due to the interband contribution is presented in this article. Initially, the lower frequency limit for the interband conductivity inclusion is studied, highlighting that even in the far-infrared regime, it should not be ignored. Then, a precise vector-fitting technique is utilized to decompose the analytical conductivity function into complex conjugate pairs. Every pair is connected to a complex surface current, while the frequency dispersion is evaluated via a proper recursive convolution scheme. Finally, a straightforward algebraic manipulation is conducted to eliminate the complex terms from the updated equations of the electromagnetic components, concerning the finite-difference time-domain (FDTD) algorithm. The precision and efficiency of the proposed methodology are thoroughly validated by comparing the numerically extracted surface wave propagation characteristics to those obtained in terms of analytical expressions.
Computation of Torque using different non-conforming Interface Techniques

In this work, the influence of classical mortaring and Nitsche-type mortaring on the torque, calculated via Maxwell's stress tensor, is determined. First, the influence of the element distortion of quadrilateral and triangular elements on the torque using a conforming mesh is investigated. Subsequently, a convergence study is performed to gain insight into the influence of the Nitsche factor used in the non-conforming interface technique and to determine optimal parameters. Based on these results, the torque of a four pole squirrel cage induction motor is calculated for selected rotation speeds and compared with torque values calculated with a harmonic approach using a conforming mesh.
Safe Routing in Energy-aware IP networks

The reduction of greenhouse gas emissions represents one of the major concerns worldwide. In telecommunications, the research community and the industry are developing various solutions to decrease the energy consumption of infrastructures. In this paper, we focus on the energy efficiency of IP networks and, in particular, on energy-aware routing as a good complement to power management mechanisms inside routers. We present a safe energy-aware routing solution where the network controller leverages knowledge about device behaviors for power management to further increase energy savings. As energy saving mechanisms can impact network reliability, decisions are taken to avoid any disruption. First, we propose a mathematical model for the associated optimization problem, and then, we develop a hybrid Benders decomposition and Column generation algorithm to solve it. Finally, we present a performance evaluation on a real backbone network with two possible implementations of the solution.
Design of A LDO with Fast Transient Response for RF Chips

This work describes an improved low-dropout linear regulator (LDO) structure. A novel transient enhancement circuit is proposed, which is placed between the error amplifier and the power transistor to realize a capacitor-less LDO. On the one hand, this design accelerates the charging and discharging speed of the gate of the power transistor. On the other hand, in a wide band range, the circuit has a high power ripple suppression ability while ensuring the stability of the LDO loop. Based on a GLOBAL _FOUNDRIES 130 nm SOI-CMOS technology, a capacitor-less LDO with an input voltage of 3.1 V and an output voltage of 2.893 V is implemented. When the LDO load is switched between light load and heavy load within 1 μs, the maximum output overshoot voltage is 78mV, and the response time is only 1.13 μs, and the VDO is 200 mV. The PSRR is 60.4dB in the low frequency band. The measured LDO output voltage of the RF chip is 2.880 V with a deviation of 13 mV in contrast to the simulation result. The experimental results demonstrate that the designed LDO regulator has fast transient response performance and good comprehensive performance under load.
Global Temperature Prediction by BiLSTM Model Based on Whale Optimization Algorithm and Attention Mechanism

With the rapid development of deep learning, time series models based on neural networks have emerged at this stage, and the time series forecasting problem is one of the important research areas. Traditional time series models are only suitable for short-term forecasting and cannot achieve dynamic forecasting; while most neural network-based forecasting models have poor accuracy and stability for long-term forecasting. In this paper, we propose a bidirectional long short-term memory network (Bi-LSTM) prediction model based on whale optim-ization algorithm (WOA) and attention mechanism, and uses this model to study the global temperature change trend. Five evaluation indexes such as mean square error (MSE), mean absolute error (MAE), and goodness-of-fit $R^{2}$ are selected and compared with the commonly used ARIMA model, and it is concluded that the index data of the model proposed in this paper are better than the traditional model, and the goodness-of-fit $R^{2}$ can reach 0.92. From the prediction results, it is known that the global temperature will probably reach about $20^{\mathrm{o}}\mathrm{C}$ by the end of the 21st century, which is similar to the predicted global average temperature of the World Meteorological Organization and international database is close to the predicted temperature, and the prediction is good.
Dam crack detection based on deep learning cascade detection algorithm

In order to improve the crack detection accuracy of concrete dam surface, a cascade crack detection algorithm based on deep learning and prior information reinforcement is proposed. In the algorithm, two neural networks are cascaded to detect cracks by a cascade detection method. Prior information strengthening includes standardization and edge strengthening. When making standardized crack slices, the crack is rotated to the horizontal trend and the center of mass is placed in the section center. Meanwhile, slices belonging to the general background are removed according to the gray gradient similarity. The slices were processed with the prior information of crack edges to artificially highlight the features and reduce the difficulty of network training. The network results without prior information reinforcement and cascade detection are compared respectively to evaluate the network detection performance. The experimental results show that the accuracy rate and recall rate of concrete dam surface crack detection have been improved significantly, which proves the effectiveness of the algorithm.
Combining Multi-Features for Lung Cancer Detection in Computed Tomography Images: A Feature Fusion Model

Lung cancer is a leading cause of cancer-related deaths worldwide, emphasizing the importance of early detection. Although Computed Tomography (CT) images are widely used for diagnosing lung cancer, their high dimensionality and variability can pose challenges to accurate detection. In light of this, we have developed a novel approach to lung cancer detection using CT images, leveraging a feature fusion model. Our model integrates multiple features extracted from the images using ResNet152, EfficientNetB4, and XceptionNet to improve detection accuracy. We evaluated our model using a vast dataset of CT images and associated its performance to traditional and techniques based on deep learning that are up-to-date. The results demonstrate that our proposed feature fusion model outperforms other methods, achieving high accuracy, sensitivity, and specificity. This approach has enormous potential for improving the early detection of lung cancer, ultimately contributing to developing more effective treatment strategies.
Dual-Band Leaky-Wave Antenna Array with Large Frequency Ratio Based on Single-Layer HMSIW and SIW Structures

A novel dual-band leaky-wave antenna (LWA) array with a large frequency ratio is proposed in this paper for both C-band and Ka-band wireless applications, which is based on single-layer half-mode substrate integrated waveguide (HMSIW) and substrate integrated waveguide (SIW) with mode-composite and structure-shared characteristics. Through different feeding ports which can excite two operating modes (quasi-TE0.5,0 mode in HMSIW and TE10-like mode in SIW), bidirectional and unidirectional beams are achieved as frequency varies from 6 to 7.5 GHz in C-band and from 25 to 33 GHz in Ka-band, respectively.
Mechanochemical Synthesis of Zero-Dimensional Metal Halide Perovskites

In this work, we directly demonstrate solid-state synthesis of zero-dimensional metal halide perovskites by mechanochemical synthesis. Three representative zero-dimensional perovskites, $\text{Cs}_{4}\text{PbBr}_{6}, \text{Cs}_{2}\text{SnBr}_{6}$, and $\text{Cs}_{3}\text{Cu}_{2}{\mathrm{I}_{5}}$, were synthesized with high purity as confirmed by structural analysis and optical spectroscopy measurements. This work promotes mechanochemical synthesis as a tool for observing and understanding the structure-property relationships of low-dimensional perovskites, in addition to their potential as a facile synthesis method for large-scale synthesis of metal halide perovskites.
Fine-grained Classification of Bone Scintigrams by Using Radiomics Features

T o develop fine-grained diagnosis of lung cancer subtypes (i.e., adenocarcinoma, squamous cell carcinoma, small cell carcinoma) in regional bone scans, in this work, we propose a radimocis-based method. In the feature selection stage, multiple feature selection methods are used to extract key features from bone scintigrams. Several classifiers are developed using random forest, decision tree, naive Bayes and other algorithms to classify lesions. Experimental evaluation conducted on clinical SPECT images shows that radimocis features including morphological features and higher-order features have a significant effect on the classification performance. The best classification performance is achieved by the proposed model using LASSO and random forest algorithm, obtaining scores of 0.6202, 0.6253, 0.6202, and 0.6163 for accuracy, precision, recall, and F-1 scores, respectively.
A Ku-Band Compact Butler Matrix in GaAs for MIMO Application

A Ku-band broadband compact Butler matrix MMIC in GaAs pHEMT technology is presented in this paper. To achieve small footprint and broad bandwidth, transformer-based quadrature couplers is proposed to realize Butler matrix. The 45° phase shifters in the matrix adopt compact constant-k filters to achieve low phase fluctuation and symmetrical layout. As a proof of concept, a 4×4 Butler matrix MMIC is implemented, which only occupies a chip area of 0.815×0.76 mm2. The post-layout simulated results show low insertion loss of 1.8 dB and less than 2° phase imbalance at 15.6 GHz. For the measurement, this chip is mounted on a printed circuit board (PCB), and the tested insertion loss and phase imbalance are around 6 dB and 7° with the severe impact of the passive circuits on the PCB.
71 kHz Frequency Modulated PiezoMEMS Gyroscope

This paper reports a frequency modulated (FM) piezoelectric MEMS (piezoMEMS) gyroscope. The gyroscope uses aluminum nitride for both actuation and sensing enabling low motional impedance and thus low voltage actuation without a need for large DC bias voltage. The two orthogonally resonating axis are operated at their respective natural frequencies, from which the rotation rate is sensed by a Lissajous frequency demodulation. Gyroscope controller is implemented with a field programmable gate array (FPGA) to demonstrate a full functioning piezoMEMS FM gyroscope.
LDT: Lightweight Dirty Tracking of Memory Pages for x86 Systems

Incremental memory checkpointing is a crucial primitive required by applications such as live migration, cloning, debugging etc. In many implementations of incremental check-pointing, the memory modifications are tracked by restricting write access to memory pages using the support provided in the memory management unit (MMU) hardware. Disabling write access impacts the performance of applications because of the page faults induced in the form of permission violation on memory store operations by the applications.In this paper, we propose LDT, a light-weight memory write monitoring mechanism to support efficient incremental check-pointing. LDT is designed to work in systems with MMU support for page dirty indicators (such as dirty-bit in x86 systems) by enabling polymorphic use of the indicators such that no other subsystem is impacted because of LDT. We design and implement LDT in the Linux kernel as an alternate to the existing write-restriction based technique. We establish the correctness and comparative efficiency of LDT through extensive experimental analysis. The results show that under write-heavy workloads, LDT outperforms write-restriction based technique by a factor of 2x in execution time. For real-world workload benchmarks such as Redis, LDT results in 2% to 8% throughput improvement compared to the state-of-the-art dirty tracking technique.
Interpolative Device Models for Hafnia-Based FeFETs

A two-tier multivariate-kriging interpolation method is proposed as a computationally efficient approach to model hafnia-based FeFET devices. We investigate how well this data-driven approach captures device-to-device variabilities when applied to realistic datasets sampled from a physics-based compact model with artificial variance. The framework provides methods for future analysis of experimental data, as well as selection of device operating conditions with the aim of unveiling FeFET strengths and weaknesses and optimizing these synaptic devices for neuromorphic circuit integration.
A Compact Horizontally-Polarized End-Fire Leaky Wave Antenna Based on Coplanar Stripline

This paper presents a recently-developed compact horizontally-polarized end-fire leaky wave antenna with a series of stubs periodically-loaded within two lines of the coplanar stripline (CPS). Under this kind of loading strategy, the phase constant of the original CPS can be directly pulled down, so that the designed antenna is able to be worked on the arbitrary substrate, and easily meets the exact end-fire radiation condition. The principle of the proposed antenna prototype is discussed, and compared with other loading methods. The performances of the proposed end-fire leaky wave antenna are also simulated and verified by the measurement. The results confirm that the proposed loading strategy is an effective way to realize the end-fire radiation properties with good performance.
Video Conferencing using WebRTC

Video conferencing has become an essential tool for communication and collaboration in today’s world, especially after the recent COVID-19 pandemic. One of the most popular technologies for video conferencing is WebRTC (Web Real-Time Communication), which allows for real-time, peer-to-peer communication directly through web browsers. This study reviews the current state of video conferencing software using WebRTC. In particular, the research study will survey the features and capabilities of popular software solutions and explore the architecture of WebRTC and the protocols used for data transmission in video conferencing software. Additionally, the challenges and limitations of video conferencing for group discussion practice, including technical difficulties, connectivity issues, and privacy concerns are examined. Finally, this study provides recommendations for future research in this field, with the goal of improving the effectiveness and efficiency of video conferencing using WebRTC technology.
Reconfigurable Circularly Polarized Folded Reflectarray Antenna

A novel reconfigurable circularly polarized folded reflectarray antenna (RCPFRA) based on the circularly polarized selective surface (CPSS) is presented in this paper. The proposed RCPFRA mainly includes three parts, one upper CPSS, a lower reflectarray with electronically reconfigurable ability and a planar miniaturization broadband CP feed. The CPSS can reflect one CP wave, while it can transmit its orthogonal CP wave. Firstly, a single layer microstrip patch reflectarray element loading with one PIN diode is proposed. Through changing the on-off state of the PIN diode, this unit cell can provide 0º and 180º phase shifts with 1-bit phase quantization. Then, a RCPFRA in the X-band is designed and simulated. The simulation results indicate that the beam scanning angle of the RCPFRA achieves within the range of ±40º. Its peak radiation efficiency is about 15%, which demonstrates effectiveness of the RCPFRA design method.
Resonator-Based Analog Phase Shifter with Small Loss Variation and Phase Error

An analog phase shifter based on half-wavelength (λ/2) resonators is presented in this paper. By utilizing this approach, phase shift within the operating frequency range can be achieved by changing the center operating frequency (f0) of the λ/2 resonator. In this design, phase slope K for the proposed 180° analog phase shifter is thoroughly analyzed and relative constant K can be achieved for different f0 by studying the varactor-loaded λ/2 resonator. As a result, small phase errors can be realized. Moreover, the required capacitance ratio for the employed varactor is quite small for the proposed this design. Accordingly, the varactor internal resistance of the employed varactor can be irrelevant to the shifting phase. Therefore, small insertion loss variation can be also realized in this design. In order to verify the design concept, a fifth-order example centered at 6.5 GHz with an operating bandwidth of 650 MHz is designed and manufactured. According to measurement, the proposed design has provided 0º to 189º phase shift tuning ranges with the maximum in-band phase difference of ±8º. In addition, the maximum insertion loss variation for the proposed 180º tunable phase shifter is about ±0.2 dB.
A Dual-Band Circularly Polarized Stacked Array Antenna with High Isolation for Satellite Communication

A dual-band circularly polarized array antenna with high isolation is presented in this paper. It can receive left-handed circularly polarized (LHCP) wave in K band and radiate right-handed circularly polarized (RHCP) wave in Ka band. Using a stacked structure, it realizes a low axial ratio (AR) in both bands and a high isolation in Ka band. The full wave simulations of the element and an 8×8 array show good performance.
Service Resilience Optimization Algorithm for Intelligent Space-based System with Minimum Delay

Space-based systems have enormous economic, social and military values that make them vulnerable to interference and even attack. With the gradual development of networked and intelligent space-based systems, intelligent space-based systems can still maintain a certain service performance without paralysis when confronted with interference or attack, that is, flexible services. However, when a traditional space-based system encounters node failure, the service is directly interrupted or needs ground re-planning, and it does not have the ability of flexible service. To solve this problem, this paper presents a service resilience recovery algorithm for minimum latency. Experiments show that in the service elasticity evaluation of smart space-based systems based on real networks, the more satellite nodes there are, the better the service elasticity, and the recovery time is 42.3% shorter than the traditional random algorithm, which is 3 times higher than the nearest strategy.
A Low-Loss Wideband Dual-Frequency Transformer for 0.3-THz Harmonic Extraction in 0.13-μm SiGe BiCMOS

This paper presents a low-loss wideband dualfrequency transformer for 0.3-THz (300 GHz) harmonic extraction in 0.13-μm SiGe BiCMOS. Employing the partially coupling stacked structure, the transformer featuring the wide bandpass characteristic can successfully extract and couple the third harmonic 3f0 (300 GHz) to the output over the fundamental frequency f0 (100 GHz). The simulation results show that the transformer achieves a low insertion loss (|S21|) of 0.9 dB, input return loss (|S11|) of around 9 dB, and output power of -9.11 dBm at the third harmonic of 300 GHz. The chip including all testing pads occupies a die area of 197 µm × 190 µm.
A Low-Profile 1-Bit Reconfigurable Transmitarray Antenna

A low profile 1-bit reconfigurable transmitarray antenna (RTA) is proposed in this paper. This RTA consists of a patch antenna array as the feeding source and a 1-bit phase-reconfigurable transmitting antenna. To achieve low profile, the RTA operates in near filed of the feeding source. To eliminate the mirror lobes caused by the 1-bit phase quantization, a phase-shifting line is integrated inside each element to imitate illumination from a virtual source at the focal point. The proposed antenna prototype is composed of 8×8 elements with a low profile of 0. 44λ0 at 9.8 GHz. By changing the switching states of PIN diodes inside the elements, the main beam can be flexibly scanned up to 50° and 40° in the E- and the H-plane with the peak gain of 15.5 dBi, respectively.
Enfoques de programación entera para el Problema del Viajante de Comercio con costos en función del tiempo

El Problema del Viajante de Comercio Dependiente del Tiempo (PVCDT) es una generalizacion del clasico Problema del Viajante de Comercio (PVC) en el cual se busca un circuito de costo minimo que recorra todos los clientes, donde los tiempos (o costos) de viaje entre ellos no son constantes y pueden variar dependiendo de diversos factores. Una de las motivaciones para considerar la dependencia del tiempo es que nos permite tener una mejor aproximacion a muchas aplicaciones de la vida real, dentro de la industria y en el sector de servicios. En la literatura relacionada, existen distintas versiones del PVCDT que consideran que las variaciones se producen por diversos motivos y sobre distintos parametros. Algunas de ellas estipulan que las variaciones se producen sobre los tiempos (y/o costos) de viaje mientras que otras asumen que las variaciones se producen sobre la velocidad de viaje. Mas aun, para el primer caso, una variante asume que el tiempo de viaje depende de la posicion del arco en el circuito mientras que otra asume que depende del instante en el que se comienza a atravesar el arco. Al igual que el PVC, el PVCDT pertence a la clase NP-Dificil y por lo tanto no se conoce un algoritmo que encuentre una solucion en tiempo polinomial. En esta tesis abordamos dos de las variantes antes mencionadas mediante la formulacion de modelos de Programacion Lineal Entera. Para cada formulacion, realizamos un estudio teorico enfocado en derivar familias de desigualdades validas que exploten las caracteristicas particulares del problema. En particular, para una de las variantes, demostramos que varias de ellas definen facetas del poliedro. Desde el punto de vista practico, para las variantes consideradas desarrollamos algoritmos exactos de tipo Branch and Cut que incorporan estas familias de desigualdades validas y los evaluamos considerando instancias propuestas en la literatura, obteniendo buenos resultados que muestran que ambos enfoques son factibles para ser utilizados en la practica.