Miracle-dz/UniFAR-FTUs huggingface dataset:
LC-Tank Injection-Locked Frequency Divider with Variable Modulus

This letter presents a wide locking range variablemodulus LC ILFD designed with a dual-resonance resonator and the designed circuit was manufactured in the TSMC 0.18 µm CMOS process. The CMOS circuit’s die area is 1.02×0.93mm2. The ILFD can be used as a wide locking range divide-by-2, -3, -4 and -5 circuit, and it is found that the harmonic mixer is used for the divide-by -5 ILFD while other modulus ILFDs use the linear mixer approach. Consequently, wide-locking range is obtained for variable division ratio.
A Compact Dual-Polarized Patch Antenna Loaded With Metamaterial Unit Cell for Broadband Wireless Communication

A compact dual-polarized patch antenna loaded with metamaterial unit cell is presented in this paper for broadband wireless communication systems. The unit cell is composed of two crossed open loop resonators, which are printed on the crossed substrates. Thanks to the loading of the unit cell, a compact patch antenna is realized with two reflection zeroes. The antenna is driven by the differential ports to obtain high isolation and low cross-polarization. The proposed antenna was fabricated and measured for verification. Measured results show that the proposed antenna has the impedance bandwidth of 17 % for S11 < −10 dB with the cross polarization lower than -33 dB. Both the simulated and measured results prove that the proposed antenna can be a good candidate for the wireless communication.
Large-Scale Projection-Based Immersive Display: The Design and Implementation of LargeSpace

In this paper, we introduce LargeSpace, the world's largest immersive display, and discuss the principles of its design. To clarify the design of large-scale projection-based immersive displays, we address the optimum screen shape, projection approach, and arrangement of projectors and tracking cameras. In addition, a novel distortion correction method for panoramic stereo rendering is described. The method can be applied to any projection-based immersive display with any screen shape, and can generate real-time panoramic-stereoscopic views from the viewpoints of tracked participants. To validate the design principles and the rendering algorithm, we implement the LargeSpace and confirm that the method can generate the correct perspective from any position inside the screen viewing area. We implement several applications and show that large-scale immersive displays can be used in the fields of art and experimental psychology.
Implementation and Analysis of 3D Channel Emulation Method in Multi-Probe Anechoic Chamber Setups

The multi-probe anechoic chamber (MPAC) based method is a candidate to assess the performance of multiple input multiple output (MIMO) devices over the air. This paper investigates the core problem, channel emulation method (CEM), in MPAC setups. The CEM is utilized to map the desired channel onto the limited number of probes to synthesize the target channel environment within a certain test area. In addition, the channel in realistic propagation environment is a three-dimensional (3D) channel, which can achieve higher data transmission rate by containing both azimuth and elevation dimension. Hence, it is urgent to investigate the CEM for 3D channels in MPAC setups. In this paper, the implementation of a novel CEM for 3D channels is presented, which allocates the subpaths in a simple way and complements the drawbacks of prefaded synthesis method and spatial fading emulator. Furthermore, the impact of the target channel and probe configuration on the emulation accuracy in terms of temporal correlation function (TCF) and spatial correlation function (SCF) is discussed. Simulation results demonstrate that the emulation accuracy of TCF depends more on the motion direction of MIMO devices while that of SCF depends more on the probes distribution. Moreover, probes number decides the emulation accuracy first. If the same number of probes are applied, the coincidence of the probe configuration and the target channel determines the emulation accuracy.
An UWB Inverted F Antenna with Coupled Feeding for 5G smartphone

An UWB(ultra-wideband) antenna based on inverted F patch structure with coupled feeding for the next generation 5G smartphone are presented. The antenna fed by coupling is composed of a novel inverted F patch and a meander feedline. Three resonant modes are excited to obtain the characteristic of UWB. The simulated -6dB impedance bandwidth of the antenna is 60.8% (3.27-6.13GHz), which can cover 5G communication band (n77: 3.3-4.2GHz, n78: 3.3-3.8GHz and n79: 4.4-5.0GHz) and WiFi band (5.1-5.9GHz). The antenna exhibits good radiation efficiency performances with 76.0%-91.7% over the whole operation band.
SEBARES - Design and Evaluation of a Controller for a novel externally guided self-balancing patient rescue aid

Paramedics frequently perform physically demanding tasks during patient transport. This leads to extremely high rates of work-induced injuries and early retirement. A novel self-balancing rescue aid (SEBARES) with an additional stair climbing mechanism, which is externally guided by a paramedic, is supposed to reduce the workloads and allowing an intuitive operation and safe transport for the patient. For the self-stabilizing functionality precise and stable control at any time is crucial. In this study a sliding mode controller, which is known for robust and stable control of nonlinear applications, is designed and implemented as a first control approach for such a device. To rate the performance application specific control requirements are defined, which address critical scores such as ergonomic user forces, maximal tilt angles and maximal overshoot. In the subsequent experimental evaluation the performance of the device and the controller are determined. The sliding mode controller successfully stabilized the system and met the predefined requirements. The system was able to accelerate adequately to match typical accelerations of walking humans, forces below 20 N had to be applied during constant walking and the system was able to decelerate from 1.4 m/s to a full halt within a sufficient distance of maximal 0.41 m. Upcoming studies will include a comparative analysis of different control approaches as well as the development of the stair climbing kinematics and obstacle detection.
Extended Abstract: Documentation Development Practice in Open Source Startups - Take PingCAP as an Example

In recent years, many open source startups have been adopting a new documentation development solution -- GitHub plus Markdown. It’s an agile ‘Docs Like Code’ solution that keeps documents close to the code and applies software development tools and techniques to documentation. Although this open source documentation solution is typically adopted by open source startups or projects, it also applies to any other kind of company as long as you want to make your documentation public to users or customers. This abstract aims to introduce this new choice of documentation solution by elaborating on its practice at an open source startup called PingCAP, so as to promote its adoption in the technical communication field.
An Incorporated Control Strategy of Commutation and Conduction Torque Ripples Mitigation for BLDCM Drives in Household Appliances

In this paper, an incorporated control strategy of both commutation and conduction torque ripples mitigation for brushless DC machine (BLDCM) with the sinusoidal back electromotive force(EMF) is proposed to reduce the vibration and noise of household appliances for higher comfortable capability. Based on the combined torque ripple analysis with respect to the stator flux linkage trajectory, a three-phase voltage vector injection (TVVI) method is designed and implemented in the commutation interval to compensate the sharp dips of the stator flux trajectory for the mitigation of the commutation torque ripple, and duty cycle of the injected voltage vector could be regulated automatically. Then, a simple direct power control (DPC) method with TVVI in the PWM modulation is employed as inner-loop for BLDCM to obtain the desired waveforms of currents with the specific dc-link current sampling method, and the reduction of both conduction and commutation torque ripples is achieved. The proposed incorporated control strategy is validated through simulation experiment results, and the effect on the torque ripples are compared with the traditional approaches.
Controller Tuning by Bayesian Optimization An Application to a Heat Pump

In this paper, we consider the problem of controller tuning for an operating unit in a building energy system. As an illustrative plant example we focus on a heat pump. Since the plant is in use, the tuning method is supposed to not intervene with its operation. Moreover, the tuning procedure is supposed to be online, model-free, based only on historical data and needs to provide safety guarantees of the plant in operation. In this regard, we formulate the problem as a black-box optimization and adopt safe Bayesian optimization approaches for controller parameter tuning. These approaches are relatively new to the control community and not intensively studied in control applications. Meanwhile, the underlying systems are often expensive and performing relevant experiments is time consuming. Therefore, a crucial step prior to implementation in reality is validating the methods in simulation to verify their applicability. Toward this end, we derive a physical-based model for the heat pump and identify the unknown parameters using gray-box identification methods. Given the simulation model, we tune the controller parameters in simulation for optimal performance while considering safety constraints of the system.
Authentication for Smart Grid AMI Systems: Threat Models, Solutions, and Challenges

Advanced Metering Infrastructure (AMI) has been regarded as a foundational part of the Smart Grid (SG). Consequently, AMI security is of critical importance. In this paper, we describe and investigate the current proposed authentication schemes and techniques for AMI. We discuss the challenges and desired objectives of authentication. We also provide a review of the recent proposed schemes for AMI along with their advantages and drawbacks towards meeting the discussed challenges and objectives. Based on the current survey, we identify open issues and suggest possible future research directions.
High Gain and Low Grating Lobe Electrically Large Array Antenna by Using Fabry-Perot Cavity

In this paper, a high gain and low grating lobe electrically large array antenna is proposed by using Fabry-Perot cavity (FPC). The feeding array antenna is composed by elements with electrically large property (ELP) based on TM<sub>30</sub> mode. The FPC between a ground plane and a single-layer partially reflecting surface (PRS) made by substrate with arrays of square metal patches printed on both the top and bottom surfaces is used here to narrow the beamwidth of element patterns, thus the large grating lobes of array caused by large element spacing can be avoided. By analyzing the parameters of PRS unit cell, suitable cell spacing is determined. Finally, a <inline-formula> <tex-math notation="LaTeX">$2\times 2$ </tex-math></inline-formula> array was fabricated and measured to validate its effectiveness. Measurements demonstrate that the gain of the array can reach up 20.9dBi at the center working frequency. When the element spacing is <inline-formula> <tex-math notation="LaTeX">$1.47\lambda _{0}$ </tex-math></inline-formula>, the maximum grating lobe level at 21GHz is only −15.5dB.
Physical Analysis of Gate-Source Voltage Dependencies of Parasitic Capacitors, and Their Impacts on Switching Behavior of a Discrete Silicon-Carbide MOSFET

This paper describes a physical analysis of gate-source voltage (VGs) dependencies of parasitic capacitors of a discrete Silicon-Carbide (SiC) MOSFET. A new picture of depletion region that induces the parasitic capacitors is proposed. The proposed picture successfully explains the origins and the intrinsic relations of the $v_{GS}$ -dependencies of the parasitic capacitors. Subsequently, the effects of the VGS dependent models are considered via the detailed analysis of the switching waveforms, which clarifies their individual impacts on the switching waveforms.
Ultra-miniaturized Balanced Bandpass Filter Using GaAs-based Integrated Passive Device Technology

In this paper, an ultra-miniaturized narrowband balanced bandpass filter based on integrated passive device (IPD) technology is proposed. By using the basic principle microwave filter and mixed-mode S-parameters, a lumped-element balanced bandpass filter for the band from 4.8 to 5 GHz is designed at first. For demonstration, a design prototype based on a 200-μm GaAs substrate with 17-dB differential-mode return loss and 20-dB common-mode suppression is EM simulated by ADS software. Good agreements between theoretical and EM simulated results are obtained.
Dynamic priority assignment for SLA compliance in service function chains

In service function chaining, data flows from a particular application or user travel along a pre-defined sequence of network functions. Appropriate service function chaining resource allocation is required to comply with the service level required by the application. In this paper, we introduce a dynamic priority assignment for flows that compete for service using a particular network function in a chain. Using the recent results of the performance metrics of transient birth–death processes, we analyse this priority assignment and develop an optimal strategy for selecting a (cheap) low- or (expensive) high-priority service, given the flow's service level agreement requirements. A decision table can, thus, be created to facilitate the fast, online priority scheduling of newly arriving flows requesting service.
A New Active Zero State PWM for Six-Phase Inverter

This paper presents a new active zero state pulse width modulation (AZSPWM) that improves the performance of both switching and common-mode voltage (CMV) of six-phase drives. The new AZSPWM applies two opposite large voltage vectors instead of zero voltage vectors for synthesizing the reference voltage vector. Compared with conventional space vector PWM (CSVPWM), the switching patterns of the new AZSPWM present a symmetrical waveform, halving the switching frequency and reducing the total switching dramatically. The simultaneous switchings are also eliminated and the CMV is reduced by 1/3 in full modulation index. Simulation results show that the new AZSPWM slightly increases $\alpha-\beta$, and x-y current distortions, but these distortions rapidly decrease as modulation index increases.
A Comparative Analysis of Properties that May be Used for Malware Detection

Despite detection efforts, malware regularly makes its way onto online markets for mobile applications. There are a variety of known methods that malware developers use to disguise the intent of their applications from anti-malware software. These methods include features that can be discovered by examining the code, such as obfuscation. As such, one might try to discover malware by looking directly for these particular code features. Unfortunately, the features used by malware developers may also appear in benign applications for legitimate reasons. In order to determine if these features are effective for evasion of malware detection, we therefore need to perform a comparative analysis to see which features are more commonly associated with malware. In this manner, we try to determine if there are any specific code features that can be associated with malware that gets past existing filters. We focus in particular on the Google Play Store, and the Google Play Protect system. We consider eight different code features that could be used to reduce the effectiveness of Android malware analysis tools. By comparing malware samples and non-malware samples from the Google Play Store, we try to determine if any of these features is associated more closely with malware that has escaped detection. This is a description of work in progress, to demonstrate the utility of the approach.
Coordination Scheduling Model of Multi-Type Flexible Load for Increasing Wind Power Utilization

Wind curtailment of power grid is severe during heating period in the ‘Three North’(northwest china, north china, and northeast china) area of China, and the ‘wind-heat conflict’ causes insufficient of power system peaking, which is one of the main reasons that impacts wind power consumption. To enhancing flexibility of power system by configuring flexible load is an effective means to improving wind power acceptance. This paper, based on the dispatch of the cogeneration unit, analyzed the composition and operation rules of battery energy storage–heat storage system. Considering the constraints of power system and thermal system, the coordinative dispatching model of battery energy storage and regenerative electric boiler is established. Based on a regional power grid in the ‘Three North’ area of China is used to simulate the acceptance of wind power under different modes of operation. The results show that in the way of power alternative, the regenerative electric boiler has the best effect of eliminating wind and abandoning wind, and the environmental benefits are obvious. When the thermal storage electric boiler is matched with an excessively large new adding heat load, the thermal power unit in the electric power for heating accounts for a relatively high amount of electricity, and the efficiency of energy utilization is low. Considering the battery storage price is greatly reduced, the peak shaving effect of battery energy storage and thermal storage electric boiler coordinated operation is the most obvious, and it is of great significance for the safe and stable operation of wind power and high-wind power infiltration grid.
Sliding Mode Control with Dirty Derivatives Filter for Rigid Robot Manipulators

Although Sliding Mode Control (SMC) is shown to be a powerful method for the control of rigid robotic manipulators, it comes with disadvantages. One disadvantage is related to the fact that the terminal sliding variable vector has a nonlinear term of the velocity error. Consequently, inaccurate velocity estimation may lead to chattering phenomenon that can excite unmodeled high-frequency plant dynamics yielding to either severe vibrations in the arm or instability of the control system. To better overcome such a drawback, this paper proposes the integration of dirty derivatives filter with SMC instead of using "direct" velocity estimation methods. We justify the effectiveness of our proposed approach numerically and experimentally on a four-degree-of-freedom (DOF) robot manipulator while considering a classical SMC and two adaptive SMCs.
Data Acquisition and Analysis Methods in UAV- based Applications for Precision Agriculture

Emerging technologies such as Internet of Things (IoT) can provide significant potential in Precision Agriculture enabling the acquisition of real-time environmental data. IoT devices like Unmanned Aerial Vehicles (UAVs) equipped with cameras, sensors, and GPS receivers can deliver a variety of IoT services and applications related to fields management, by capturing images from great heights. However, there are many issues to be resolved before the effective use of UAVs in the agriculture domain, including the data collection and processing methods. There is still no standardized workflow and processes for most UAV-based applications for Precision Agriculture. In this paper, we summarize the data acquisition methods and technologies to acquire images in UAV-based Precision Agriculture and appoint the benefits and drawbacks of each one. We also review popular data analysis methods of remotely sensed imagery and discuss the outcomes of each method and its potential application in the farming operations.
Accelerated Life Test Study on Thyristors of HVDC Converter Valve

As the key component of HVDC converter valve system, thyristors have vital impact on the reliability of the entire HVDC transmission project. In order to effectively obtain the life model of thyristor, this paper uses the existing accelerated life test theory, combined with the operating conditions of the converter valve and the relevant characteristics of the thyristors, to deeply analyse the several stress levels that have the most serious impact on the life of the thyristors. An accelerated life test scheme that can effectively guide the life model of the thyristor, according to the test data collected by this test method, the thyristor junction temperature life model under the short-circuit current stress is established, and compared with the thyristor failure rate in the practical engineering, the results show the feasibility of the test scheme and the correctness of the life model.
Optimal Path Tracking Control of Autonomous Vehicle: Adaptive Full-State Linear Quadratic Gaussian (LQG) Control

In practice, many autonomous vehicle developers put a tremendous amount of time and efforts in tuning and calibrating the path tracking controllers in order to achieve robust tracking performance and smooth steering actions over a wide range of vehicle speed and road curvature changes. This design process becomes tiresome when the target vehicle changes frequently. In this study, a model-based Linear Quadratic Gaussian (LQG) Control with adaptive Q-matrix is proposed to efficiently and systematically design the path tracking controller for any given target vehicle while effectively handling the noise and error problems arise from the localization and path planning algorithms. The regulator, in turn, is automatically designed, without additional efforts for tuning at various speeds. The performance of the proposed algorithm is validated based on KAIST autonomous vehicle. The experimental results show that the proposed LQG with adaptive Q-matrix has tracking performance in both low (15kph) and high (45kph) speed driving conditions better than those of other conventional tracking methods like the Stanley and Pure-pursuit methods.
A Feedback Linearization Based Approach for Fully Autonomous Adaptive Cruise Control

This paper presents a novel approach to design a stop-and-go Adaptive Cruise Control system for autonomous vehicles featured by low computational cost and suitable for running in real-time on an embedded microprocessor. The control scheme uses feedback linearization approach to deal with system non-linearities, which allows the use of linear control techniques to guarantee the respect of the safety distance, with respect to the in front target vehicle, in both steady state and transient navigation conditions. Moreover, a new safety distance formalization is introduced and its effectiveness has been validated in simulation and on-road.
Hybrid Antenna Selection for Massive MIMO

Although antenna selection (AS) is an effective way to decrease the hardware’s cost and complexity in massive multiple-input multiple-out (MIMO) systems, its computational complexity is becoming a problem for a large number of BS antennas. To reduce the complexity of AS, two hybrid AS schemes are proposed for massive MIMO in this paper, i.e. selection-selection AS and group-selection AS. The former is a selection-selection hybrid scheme and the latter is a group-selection hybrid scheme. Two proposed AS schemes can decrease the computational complexity effectively at a small cost in capacity performance loss, demonstrated by the presented numerical simulation results.