Miracle-dz/UniFAR-FTUs huggingface dataset:
3D Lightweight Broadband Terahertz Absorber Based on Reduction Graphene Oxide

With the development of terahertz (THz) communication and detection technology, great attentions have been paid to terahertz absorbing and shielding materials. In this work, and lightweight and high-performance terahertz wave absorber with a three-dimension structure is designed and fabricated. Due to the excellent impedance matching on the macroscopic interface and the multiple reflection/absorbing inside the micropores structure, the obtained 3D reduction graphene oxide (3D-rGO) pyramidal absorber, shows a best average absorption intensity (AAI) of -30 dB. The bandwidth for strong absorption with the reflection loss (RL⩽-20 dB) covers 93% of the entire test band from 0.3~1.2 THz. This strategy of combining pyramidal absorbing unit with porous conductive materials pay the way to realize high-performance THz absorbers for practical applications.
High Gain and Large Beam-pointing Angle Conical Beam Antenna with Dielectric Lens

A high gain and large beam-pointing angle conical beam antenna with a dielectric lens is presented in this paper. The dielectric lens is designed to improve the gain of the antenna and move the maximum radiation gain towards large beam-angle. Most importantly, we derive the design equations to determine the surface shape of the lens. A prototype is presented to verify the correctness of the formula. The simulated results demonstrate that the antenna is operated at 33 GHz, and it has achieved the gain of around 10.1 dBi with maximum beam-pointing angle of around 45°. In addition, its 10 dB relative impedance bandwidth is about 16% ranging from 29.7 GHz to 35.3 GHz.
Enhancing Semantic Relation Classification With Shortest Dependency Path Reasoning

Relation Classification (RC) is a basic and essential task of Natural Language Processing. Existing RC methods can be classified into two categories: sequence-based methods and dependency-based methods. Sequence-based methods identify the target relation based on the overall semantics of the whole sentence, which will inevitably introduce noisy features. Dependency-based methods extract indicative word-level features from the Shortest Dependency Path (SDP) between given entities and attempt to establish a statistical association between the words and the target relations. This pattern relatively eliminates the influence of noisy features and achieves a robust performance on long sentences. Nevertheless, we observe that majority of relation classification processes involve complex semantic reasoning which is hard to be achieved based on the word-level statistical association. To solve this problem, we categorize all relations into atomic relations and composed-relations. The atomic relations are the basic relations that can be identified based on the word-level features, while the composed-relation requires to be deducted from multiple atomic relations. Correspondingly, we propose the Atomic Relation Encoding and Reasoning Model (ATERM). In the atomic relation encoding stage, ATERM groups the word-level features and encodes multiple atomic relations in parallel. In the atomic relation reasoning stage, ATERM establishes the atomic relation chain where relation-level features are extracted to identify composed-relations. Experiments show that our method achieves state-of-the-art results on the three most popular relation classification datasets – TACRED, TACRED-Revisit, and SemEval 2010 task 8 with significant improvements.
Probabilistic Loss Sensitivity Analysis in Power Distribution Systems

Power distribution systems are changing due to renewable energy integration, electric vehicle penetration and active consumers engaging in the energy market. Therefore, utilities need to quantify the impact of such changes on the system. Power loss is one of the tools to quantify system performance. A huge share of losses occurs on the distribution side due to lower voltages compared to transmission systems. Existing methods that quantify the impact of consumer activities on losses are scenario-specific, computationally expensive and do not consider uncertainties associated with power changes. Therefore, the goal of this paper is to develop a simpler, yet accurate, probabilistic loss sensitivity framework for approximating the impact of random power changes on power losses. First, an analytical expression is derived to approximate the change in line losses for any given deterministic power changes. Then, the analytical expression is extended to a probabilistic framework that accommodates variability related to power changes. The proposed approach is validated via simulation against the traditional load flow-based sensitivity method using the IEEE 69 node test system. Results demonstrate that the proposed approach is accurate and computationally efficient. The proposed framework is useful for real-time loss monitoring and optimal asset management.
Process Condition Effects on Saddle Fin Profile and Its Device Performance Below 20nm Advanced DRAM

In this paper, a 16nm saddle fin structure was modeled. Active area width (AA CD), AA tapper angle, buried word line trench width (BW CD) and BW tapper angle effects on the device performance were investigated using a built-in drift-diffusion solver. Our analysis confirms that the smaller AA tapper angle and proper AA CD can generate higher on-state current (Ion) and lead to lower off-state current(Ioff). In addition, in our fin sputter model, lower sputter ratio increase Ion, and lower sputter angle reduce Ioff and subthreshold swing(SS).
Performance of Surrogate-Assisted Optimization for Antennas

Recently, various global optimization methods from the evolutionary computation field have been applied to antenna design problems and have indicated promising results. Especially, surrogate-assisted-optimization provides a more efficient way for antenna design to greatly reduce the electromagnetic simulation cost. In this work, the performance of surrogate-assisted-optimization for antenna design is explored using the typical function usually representing antenna problems. The results show that SAO and heuristic methods such as the differential evolution method are suitable for different types of landscapes.
Changeable moving-goal tracking for robots in the environment of dynamic multi-obstacles

When a robot is required to track a moving object in dynamic environment,a dynamic algorithm must be taken.An algorithm called rolling timeframe biased rapidly-exploring random tree is proposed in this paper.Based on the analysis of the stochastic characteristics of rapidly-exploring random tree,a parameter called bias is introduced to speed up the search.Taking advantages of the rolling timeframe,robots collect the information of dynamic obstacles and object at the beginning of a period,and estimate their distributions in operation space of next timeframe.The robot plans local path using biased rapidly-exploring random tree algorithm.After many times of such local planning,the robot gets its object at last.Simulation results show that the algorithm can obtain good results in tracking the object with changing direction in dynamic environments.
A Graded-Gate Structure of AlN/GaN HEMT for High-Linearity Applications

In this article, a high-linearity AlN/GaN high-electron-mobility transistor with graded-gate length along the gate width direction was demonstrated. The device is used in high-linearity applications by employing a structure with a graded-gate length along the gate width direction. The graded-gate structure is achieved by using the method of over-development technology. As results show, by changing the appropriate process conditions such as development time, the fabricated graded-gate length structure has a significant impact in optimizing the transconductance profile, thereby improving the linearity of GaN HEMTs. The device exhibits an Id,max of 1735 mA/mm, a gm,max of 273 mS/mm with a gate voltage swing of the transconductance plateau up to 5.5 V and a difference in peak extrinsic transconductance of 1.85 mS/mm. In addition, the device has a radio frequency (RF) performance of fT/fmax=89/150 GHz for an equivalent gate length of 100 nm. The devices fabricated in this article have great potential for improving the linearity of mmWave RF devices, which has significance for future 5G wireless communications.
Pattern Reconfigurable Hemispherical Conformal Antenna Array

A novel pattern reconfigurable hemispherical conformal antenna array with low profile and miniaturization is designed, which can realize the reconfiguration of four modes. The antenna array consists of a radiation part and a feeding network. The radiation part adopts 4 double quasi-rhombic dipole end-fire antennas to achieve high gain and stable radiation, and the feeding network is cascaded by four hybrid couplers to achieve different output phase configurations. The simulated reflection coefficient shows that the bandwidths of ports 1, 2, 3, and 4 are 8.43-12.17GHz, 8.29-11.15GHz, 8.67-11.15GHz, and 8.29-8.93GHz, respectively, when |S11| < -10 dB. The sum beam gain is 10.29-10.35dBi, and the difference beam gain is 4.12-7.2dBi.
An AI Predicted Capacitance-Based Electromagnetic Analysis Method about Metal Fill Effect for 5G/B5G Applications

An electromagnetic analysis method based on artificial intelligence predicted capacitance for 5G/B5G chip with metal fills is proposed. The influence of the metal fills is efficiently evaluated by the effective permittivity of the dielectric layer containing metal fills. Artificial intelligence is used to accurately and efficiently evaluate the parasitic capacitors about the metal fills, which enables very approximate estimation of the effective permittivity. For verification, the S-parameters of an on-chip inductor using the proposed method and direct computation are compared.
A Dual-band Antenna for LTE/mm-Wave Mobile Terminal Applications

In this paper, a dual-band antenna that integrates a millimeter-wave (MMW) substrate integrated dielectric resonator antenna (SIDRA) beam-steerable array and an LTE planar inverted-F antenna (PIFA) is proposed. The SIDRA, which is a 1×4 connected DRA array, is developed in the clearance area of the PIFA. By properly locating the SIDRA array, the performance of PIFA will not be deteriorated. The LTE PIFA can cover the band of 1.77 GHz - 2.62 GHz (38.6%) and achieve a peak gain of 4.3 dBi, while the MMW array can cover the band of 26.2 - 29.9 GHz (13.2%) and achieve a peak gain of 12.4 dBi. The MMW array can support beam-steering angles of ±45°. Due to the high space utilization of the proposed design strategy, the dual-band antenna is suitable for 5G mobile terminal applications.
A Novel Two-Stage Net for Human Body Region Segmentation via Centimeter-Wave Radar

Human body region segmentation is a sub-task in semantic segmentation. Due to the size, complexity, abstraction of radar signal and the lack of open source datasets of radar signal data, the radar signal is rarely used for human body segmentation in past. In recent years, with the development of deep learning, some radar signal data from unmanned drive has been used for research on classification, target detection and semantic segmentation. In this paper, a novel two-stage neural network model based on centimeter-wave radar sensor is designed for human body region segmentation. In the first stage, radar signals are encoded and compressed, in the second stage, decode the spatial feature information of the human body extracted by the encoder to output the segmentation results. The network adopts the design idea of teacher-student network, which use the teacher network to annotate radar signal data and provide cross-modal supervision for the student network. We collected human body data in different scenes, and input the radar signal into the model, performs human body region segmentation. The effectiveness of this human segmentation model is experimentally verified for single and multi-person scenes, especially for occlusion scenes.
Electroplating of 3D Printed Plastic Component for the Application of Microwave Filter

3D printing technologies offer attractive solutions for manufacturing complex microwave components for high-power applications, such as satellite antennas. Metal additive manufacturing usually requires expensive power and printing equipment, and the components are very heavy. How to produce lightweight microwave components in a fast and low-cost way is a challenge that needs to be solved. In this paper, we present a novel method to manufacture microwave filters by electroplating 3D printed thermoplastics and thermoset materials. The design concept of generating slots for better electroplating of the inner walls of microwave components is introduced. Since the slots do not cut the current flow, microwave field distribution is not influenced. Filter structures based on 3D printed plastics, coated with copper skin are produced. The coaxial filters with or without slots are studied, and a comparison with CST results is conducted to understand the benefits and limitations of this technology.
An ultra-wideband time-domain antenna

The theory of the transient electric-field pulses testing receives extensive attention in the fields of national defense and industry. How to measure the transient electric-field pulses efficiently and accurately is an urgent problem to be solved in electromagnetic countermeasures. Ultra-wideband time-domain antennas are the core component of the transient electric-field measurement systems. In this paper, an ultra-wideband time-domain antenna is proposed to measure the transient electric-field pluses. The proposed antenna is based on progressive conical dipole structure, which couples electric-field energy through a pair of differential dipoles. The simulation and measurement results show that the proposed antenna has excellent differential characteristics in the frequency range of 10MHz~1GHz. The proposed antenna has advantages of wide operation frequency, small size, simple processing and low cost.
Terahertz Phase Shift of Circularly Polarized Wave and Faraday Rotation in Magnetized YIG Crystal

Faraday rotation is a fundamental property present in magneto-optical elements. In the terahertz (THz) range, yttrium oxide iron garnet (YIG) displays obvious Faraday rotation under a weak external magnetic field (EMF) at room temperature. Here, the phase shift of conjugate circularly polarized (CP) light and the Faraday rotation effect in YIG crystal were experimentally investigated at THz frequency under different EMFs. The experiment result shows that the phase shift of left-handed (LCP) and right-handed circularly polarized (RCP) light has the opposite responses to the EMF, which reach 25.8° and −22° respectively. And the Faraday rotation angle attains up to 13°. The work about the phase shift of CP light and Faraday rotation in the YIG crystal is of great significance for THz nonreciprocal transmission devices and modulators which work at room temperature.
Role of Radiative–Convective Feedbacks in Spontaneous Tropical Cyclogenesis in Idealized Numerical Simulations

AbstractThe authors perform 3D cloud-resolving simulations of radiative–convective equilibrium (RCE) in a rotating framework, with interactive radiation and surface fluxes and fixed sea surface temperature. A tropical cyclone is allowed to develop spontaneously from a homogeneous environment, rather than initializing the circulation with a weak vortex or moist bubble (as is often done in numerical simulations of tropical cyclones). The resulting tropical cyclogenesis is compared to the self-aggregation of convection that occurs in nonrotating RCE simulations. The feedbacks leading to cyclogenesis are quantified using a variance budget equation for the column-integrated frozen moist static energy. In the initial development of a broad circulation, feedbacks involving longwave radiation and surface enthalpy fluxes dominate, which is similar to the initial phase of nonrotating self-aggregation. Mechanism denial experiments are also performed to determine the extent to which the radiative feedbacks that are e.
Web-based personal access control system using facial recognition with deep learning techniques

This paper presents a web application to control personnel access to a work area without contact; this makes it ideal to help combat the Covid-19 health emergency. For its implementation, deep learning and computer vision techniques have been used for face detection and recognition. The system consists of four phases, the first one aimed at detecting and aligning the face with deep learning algorithms. The second phase obtains the facial features to recognize different people. The third phase consists of implementing a module that detects face impersonation, and significantly prevents possible attacks on the system by identifying whether the face is real or fake; and the last phase is the design and development of the web interface. This interface performs the communication of the algorithms, the users and the administration. In order to evaluate this proposal, several experiments have been carried out under diverse real conditions. The main results to correctly identify the user show that it has an accuracy of 99 %, in an estimated time of 3 seconds, in the range of 20 cm to 90 cm away, with respect to the camera. In addition, the system is capable of identifying users wearing masks or glasses, in this case with an accuracy of 95% in 4 seconds.
An Injection Locked Frequency Divider-by-Two with Harmonic Enhancement

This paper presents an injection-locked frequency divider (ILFD) that can operate at 40 GHz. The enhanced harmonic structure to broaden the locking range is proposed. Simulated in a 65nm CMOS process, the proposed ILFD has a locking range of 43% from 31 GHz to 48 GHz for divider-by-two with 4.2mW dc power.
On-chip canary circuit design for electronic interconnects by utilizing RF resonance peak movement as a prognostic factor

This paper presents that S-parameter patterns can capture initiation and propagation of the cracks in electrical interconnects. Especially, resonance peak movement in the radio frequency (RF) region can be an effective prognostic factor. Furthermore, we designed and simulated an on-chip canary circuit utilizing this factor, which can monitor health of the interconnects.
Enhancement in Bipolar Conductance Linearity by One Transistor - One Resistor (1T1R) cell with Non-Filamentary PCMO-RRAM as Synapse for Neural Networks

This work reports conductance linearity enhancement in one-transistor-one-RRAM (1T1R) cell with non-filamentary PCMO-RRAM. First, we show analog resistive switching of PCMO-RRAM(1R) in DC-IV. Second, we demonstrate gradual conductance change (potentiation (LTP) /depression (LTD)) in transient-IV. Third, an electrical connection defined between a commercialized transistor and fabricated PCMO-RRAM emulates 1T1R, demonstrating resistive switching via transistor(1T). Finally, improved conductance linearity $(25X\ in\ LTP/5X\ in\ LTD)$ with 1T1R is shown, which is best compared with state-of-the-art RRAM devices.
Modelling of Substrate Integrated Shielded Asymmetrical Coplanar Stripline and Its Transition to Coaxial Line

The modelling of multilayer substrate integrated shielded asymmetrical coplanar stripline (SACPS) and its transition to coaxial line are presented. The substrate integrated SACPS contains a layer of asymmetrical coplanar stripline (ACPS), two layers of air cavity, and the top and bottom shielding layers. The side shielding is realized by using metallized vias. The substrate integrated SACPS supports the quasi-TEM dominant mode and has merits of low loss, low dispersion, low permittivity, low profile, and easy for integrating series and parallel surface mounting devices. The characteristic impedance of the substrate integrated SACPS is analyzed by using different parameters. The transition between the substrate integrated SACPS to coaxial line is presented with compact size, low loss, and wide bandwidth.
Improved FCM Algorithm using Entropy-based Weight and Intercluster

This paper proposes an improved FCM(Fuzzy C-means) algorithm using intercluster and entropy-based weight in gray image. The fuzzy clustering methods have been extensively used in the image segmentation since it extracts feature information of the region. Most of fuzzy clustering methods have used the FCM algorithm. But, FCM algorithm is still sensitive to noise, as it does not include spatial information. In addition, it can't correctly classify pixels according to the feature-based distributions of clusters. To solve these problems, we applied a weight and intercluster to the traditional FCM algorithm. A weight is obtained from the entropy information based on the cluster's number of neighboring pixels. And a membership for one pixel is given based on the information considering the feature-based intercluster. Experiments has confirmed that the proposed method was more tolerant to noise and superior to existing methods.
Design of Dual-Band Gysel Power Divider With Filtering Responses

In this paper, a new dual-band Gysel filtering power divider (FPD) suitable for high-power application is proposed. A dual-band coupling structure based on centrally loaded resonators is utilized to provide a ±90° phase shift in both passbands. Therefore, it is used as a K-inverter to replace the quarter-wavelength microstrip line in the power divider. And the second frequency can be flexibly adjusted thanks to the use of centrally loaded resonators. According to the modified topology of gysel power divider, the calculation expressions of circuit parameters are given. In order to verify the theory, an equal dual-band Gysel FPD is designed. The simulation results have three transmission zeros beside the passband, resulting in high-selectivity quasi-elliptic responses; the results also show that the structure integrates the filter and the power divider well, and it has good advantages for high-power application.
Operation and Application Guidance for the Ground Based Dual-band Radiometer

A TP/WVP-3000A, ground-based microwave radiometer, that was first introduced to South Korea has been operated since August 22, 2007 at the National Center for Intensive Observation of Severe Weathers (NCIO). Using the dual-band, the radiometer provides temperature and humidity soundings from the surface up to 10 km height with the high-temporal resolution of a few minutes. In this study, the performance of the radiometer on the predictability of the high impact weathers was evaluated and various practical applications were investigated. To verify the retrieved profile data from the radiometer, temperature and relative humidity soundings are compared with those from the rawinsonde launched at the NCIO and Gwangju station. The root mean squared errors for temperature and relative humidity soundings were smaller under rainy weather conditions. The correlation coefficient between PWVs (Precipitable Water Vapors) obtained from the radiometer and Global Positioning System satellite at Mokpo station is 0.92 on average. In order to investigate the structure and characteristics of precipitation, stability indexes related to rainfall such as the Convective Available Potential Energy (CAPE), K-index, and Storm RElative Helicity (SREH) were calculated using windprofiler at the NCIO from 14 to 16 September, 2007. CAPE and K-index tended to be large when the thermodynamic unstability was strong. On the other hand, SREH index was dominantly large when the dynamic unstability was strong due to the passage of the typhoon 'Nari'.