Miracle-dz/UniFAR-FTUs huggingface dataset:
Space-Frequency Shift Keying in Rapidly Time-Varying MIMO OFDM Channels

In this paper, the scheme to achieve transmit diversity in the rapidly time-varying (RTV) multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) channel is studied. Concretely, two schemes named space-frequency shift keying (SFSK) and generalized SFSK (GSFSK) are proposed. In the proposed SFSK, the space-frequency dispersion matrices are constructed by the circular shifting of sparse vectors, and each modulation symbol is transmitted in one space- frequency resource block according to the pattern determined by the activated dispersion matrix. While in the proposed GSFSK, multiple dispersion matrices are activated to modulate multiple symbols in one space- frequency resource block simultaneously, and thereby a higher spectral efficiency is achieved. Next, the capacity of the proposed schemes to achieve the transmit diversity gain is validated through the analysis of the asymptotic diversity order. Moreover, a correlation-based detector is presented to reduce the detection complexity of both SFSK and GSFSK. Finally, the performance of the proposed schemes are demonstrated by computer simulations.
Circularly polarized cross-slot antenna array fed by substrate integrated waveguide

A circularly polarized antenna array is proposed by loading a cavity-backed cross-slot antenna over the longitudinal slots on the SIW upper layer in this paper. The longitudinal slots are etched to couple energy to array from SIW. The cavity-backed cross-slot antenna is designed to achieve CP radiation. The radiation unit has good isolation characteristic, which is desirable to design a circularly polarized antenna array. A 1-by-8 circularly polarized array operating at 10 GHz has been developed. Simulated impedance bandwidth of 4.6%, the 3-dB axial ratio bandwidth of 2.1%, the gain of 13.82dB and cross polarization levels of about 24.22dB have been achieved. Moreover, the proposed antenna owns the easy processing and the low profile. It can be conveniently expanded to a larger wideband CP array with a higher gain, which is preferred for the specific satellite communication applications.
A Hierarchical MEC Architecture: Experimenting the RAVEN Use-Case

Low latency communication with end-user and knowledge of real-time network information, such as radio conditions and network statistics, are among two key advantages of Multi-access Edge Computing (MEC) technology. In this paper, we propose a hierarchical MEC architecture and present a proof-of-concept (PoC) implementation of a Radio Aware Video optimization in a fully Virtualized Network (RAVEN) use case. The PoC has been assembled in a small-scale LTE network based on OpenAirInterface and commercial terminals, representing a scenario where a real-time adaptive video streaming service is provided at a Mobile Edge platform serving multiple eNBs. Real-time radio information is provided by eNB agents which act as local controllers co-located with eNB, collecting and providing realtime access to the requested RAN data. Agents can cooperate with each other to control the network in a distributed manner or can be delegated and/or controlled by a master controller entity. Information gathered by eNB agents is thus provided to the MEC system, allowing other MEC apps to consume it. The results of the RAVEN experimental activity demonstrate the benefit of recently ETSI MEC specified RNI (Radio Network Information) service in improving the perceived user quality of experience.
MOT: A Compatible Transport Mechanism of Mobile Edge Computing and Conventional Traffic

In recent years, the mobile edge computing (MEC) has achieved various of research interests. By offloading data from the user equipments (UEs) to the MEC servers, many computationally demanding applications can be processed at the edge of the mobile networks. However, the data offloading of MEC needs to share the bandwidth with the conventional traffic in the mobile edge link. Simply using TCP on MEC offloading causes bandwidth robbery to the conventional TCP traffic. On the other hand, in the highly lossy wireless link environments, TCP fails to satisfy the MEC's strict requirement on the short transport delay. Therefore, we propose the MEC offloading transport (MOT) mechanism. MOT uses the prioritized queueing to avoid bandwidth robbery to the conventional traffic, and also uses the per-hop reliability to achieve loss-insensitive bandwidth utilization. The evaluation results show that MOT successfully avoids degrading the QoS of the conventional services, and achieves almost full utilization on the remaining bandwidth.
A Multilevel Predictive Model for Detecting Social Network Users with Depression

The society is currently witnessing an unprecedented growth in the incidence of mental disorders, with an estimated 300 million people suffering from depression globally. People with high life satisfaction tend to suffer fewer mental health issues. The large volume of data generated on social network platforms enables us to detect hidden patterns in data and obtain new insights. This work aims to (a) explore the relationship between life satisfaction and depression in social network users, using Facebook as an example, and (b) develop a multilevel predictive model to detect users with depression. We trained a set of predictive models on datasets from myPersonality project including 2,085 participants who took the Satisfaction with Life Scale and 614 users who submitted the Centre for Epidemiological Study Depression (CES-D) scale. The resulting multilevel model establishes a negative correlation between life satisfaction and depression, and it can also improve the accuracy of a predictive model using depressive labels alone.
Continuous and reconfigurable doherty power amplifier using tunable comb structure

The design of continuous and reconfigurable Doherty power amplifier (DPA) using tunable comb structure is presented in this paper. Two Cree GaN HEMTs with 10-W peak envelope power are employed to design the continuous and reconfigurable DPA. Layout simulation results show that the continuous and reconfigurable DPA achieves a power-added efficiency (PAE) of 40%–60% at the peak power and a PAE of 30%–40% at the 6-dB backoff point from the saturated output power from 0.81GHz to 1.35GHz.
Moisture-Induced Die Stresses in PBGA Packages Exposed to Various Environments

Plastic Ball Grid Array (PBGA) technology has been proven to be one of the most popular packaging solutions with many advantages in thermo-electro-mechanical performance, reliability as well as cost effectiveness. While a number of studies have been conducted to investigate the package reliability using a wide range of experimental methods such as thermal cycling, thermal shock, vibration, drop test, etc., there are quite limited studies on the effects of moisture on PBGA packages. The mold compound and PCB substrate are two primary components in PBGA package; they however absorb moisture when subjected to high humidity environment, generating stress changes in the package die and potentially causing delamination in the package interfaces. In this study, the effects of moisture on die stresses in Plastic Ball Grid Array (PBGA) packages have been characterized. On-chip piezoresistive sensors were used to measure moisture-induced device side die stress in the packages under three different moisture conditions (65% RH and 65 °C; 85% RH and 85 °C, and 95% RH and 95 °C). The measurements were carried out in both absorption and desorption process to evaluate the reversibility of the moisture effects. In addition to the experimental measurements on package level, a study on the moisture properties of the BT substrate and mold compound in the PBGA was completed. The moisture properties (Diffusivity D, Saturated Concentration Csat, and Coefficient of Moisture Expansion β) of each material were experimentally obtained. Finally, a finite element numerical simulation was performed to validate the experimental results. The moisture properties obtained earlier were used in the model. Good agreements between numerical predictions and experimental results were observed.
Gas exchange and hydraulics during drought in crops: who drives whom?

This article comments on: Wang X, Du T, Huang J, Peng S, Xiong D. 2018. Leaf hydraulic vulnerability triggers the decline in stomatal and mesophyll conductance during drought in rice (Oryza sativa). Journal of Experimental Botany 69, 4033–4045.
Secure Throughput Optimization of Selective Decode-and-Forward with Finite Blocklength

In this paper we investigate the secure throughput of selective decode-and-forward relaying where the legitimate transmitter has no knowledge of the instantaneous channel state information with respect to neither the legitimate receiver nor the eavesdropper. Moreover, we assume a delay-critical scenario, such as in some applications of machine- to-machine communications, so that users communicate with a finite and short blocklength. The performance of direct and selective decode- and-forward cooperative communication strategies are compared. Our results show that the optimization of the blocklength, subject to a maximum length imposed by the particular application, yields important gains in terms of the secure throughput, while cooperative communications is shown to outperform direct non- cooperative transmission.
Reducing CQI Feedback Overhead by Exploiting Spatial Correlation

Spatial wireless channel prediction is crucial for future wireless networks, and in particular, for predictive resource allocation. In this paper, we first predict the channel quality indicator (CQI) at an arbitrary test user based on the Gaussian process regression (GPR) method. Second, in order to limit the overall signalling overhead, we exploit the correlation property of the wireless propagation channel. The performance of the proposed method is evaluated by the Cram'er- Rao bound (CRB). Simulation results not only well demonstrate the potential of our proposed method, but also match with the theoretical analysis.
Learning from Delayed Outcomes with Intermediate Observations

Optimizing for long term value is desirable in many practical applications, e.g. recommender systems. The most common approach for long term value optimization is supervised learning using long term value as the target. Unfortunately, long term metrics take a long time to measure (e.g., will customers finish reading an ebook? ), and vanilla forecasters cannot learn from examples until the outcome is observed. In practical systems where new items arrive frequently, such delay can increase the training-serving skew, thereby negatively affecting the model's predictions for new products. We argue that intermediate observations (e.g., if customers read a third of the book in 24 hours) can improve a model's predictions. We formalize the problem as a semi-stochastic model, where instances are selected by an adversary but, given an instance, the intermediate observation and the outcome are sampled from a factored joint distribution. We propose an algorithm that exploits intermediate observations and theoretically quantify how much it can outperform any prediction method that ignores the intermediate observations. Motivated by the theoretical analysis, we propose two neural network architectures: Factored Forecaster (FF) which is ideal if our assumptions are satisfied, and Residual Factored Forecaster (RFF) that is more robust to model mis-specification. Experiments on two real world datasets, a dataset derived from GitHub repositories and another dataset from a popular marketplace, show that RFF outperforms both FF as well as an algorithm that ignores intermediate observations.
Treatment satisfaction significantly improves in patients with multiple sclerosis switching from interferon beta therapy to peginterferon beta-1a every 2 weeks

Objectives Posthoc analysis of treatment satisfaction in patients switching to subcutaneous (SC) peginterferon beta-1a in the ALLOW study. Patients and methods Patients with relapsing multiple sclerosis treated with intramuscular interferon (IFN) beta-1a or SC IFN beta-1a or beta-1b remained on their current therapy for a 4-week run-in period, followed by a switch to SC peginterferon beta-1a 125 mcg every 2 weeks for 48 weeks. Treatment satisfaction was measured using the Treatment Satisfaction Questionnaire for Medication (TSQM), which covers effectiveness, side effects, convenience, and global satisfaction. Patients completed the TSQM at baseline (prior to starting the 4-week run-in period) and 4, 12, 24, 36, and 48 weeks after switching, and scores were analyzed for the overall population and compared to baseline. Patients reported the severity of flu-like symptoms (FLS) at baseline and with each peginterferon beta-1a injection; clinicians evaluated the occurrence of injection-site reactions (ISRs) after the first dose of peginterferon beta-1a and every 12 weeks thereafter. TSQM scores were stratified by the presence of FLS or ISRs during the study period and by prior IFN therapy use. Results For the overall population (n=194), convenience and global satisfaction scores significantly improved from baseline at all time points, and side effect satisfaction scores significantly improved up to week 36. Convenience scores significantly improved regardless of FLS, ISRs, or prior IFN therapy. Patients without FLS during the study period showed significant improvements in global satisfaction, but not side effect satisfaction, versus those with FLS. Patients switching from SC IFN therapies achieved greater improvements in treatment satisfaction than patients who switched from intramuscular IFN beta-1a. Conclusions Switching relapsing multiple sclerosis patients to SC peginterferon beta-1a from other IFN therapies significantly improved treatment satisfaction and convenience.
Wideband microstrip MIMO antenna for millimeter-wave applications

This paper presents a wideband planar antenna based on microstrip structure. By loading shorted vias on the specific location of the microstrip line, and carefully choosing the size of feeding line, good impedance matching and high peak gain can be achieved. The multiple-input-multiple-output (MIMO) antenna for millimeter-wave (mm-wave) applications is also designed. The simulated results of the proposed MIMO antenna show good performance in impedance bandwidth, isolation, peak gain and radiation patterns.
Application of 3-D metal printing to microwave components and antennas

3-D printing has been developed very rapidly in microwave device applications over the past few years. Metal printing is an additive manufacturing technique of synthesizing metallic parts from metal alloy power, which is totally different from the traditional machining method or “subtractive manufacturing”. The latter usually introduces some errors in terms of accuracy, alignment and assembly, inevitably degrading the performance of the devices, especially the efficiency at high frequency. This paper looks at the application of Direct Metal Laser Sintering (DMLS) to microwave components and antennas. The advent and the maturing of the DMLS technology may revive the fortunes of these devices as designs that are previously difficult to fabricate can be now easily handled. Some newly developed examples implemented via DMLS technique are also included in this paper.
Polarization conversion with asymmetrical and symmetrical metasurface

In this paper, we establish a generic formula for calculating the circular polarization preservation and conversion rate of metasurfaces based on the Jones matrix method. Specifically, we analyze the polarization state of light reflected from two types of classical metasurfaces: asymmetrical and symmetrical. We also explore the bandwidth of co circular polarization reflectance and the thickness of the dielectric layer. This progress provides useful criteria for designing metasurface-based polarizers.
Investigation of Microstructural Evolution in SAC Solders Exposed to Short-Term and Long-Term Aging

The microstructure and mechanical properties of Sn-Ag-Cu (SAC) solder joints in electronic assemblies are constantly evolving when exposed to isothermal aging. In particular, both the stress-strain behavior and creep behavior of SAC solders degrade significantly with aging exposures. These changes in solder mechanical behavior are a result of the evolution of the solder microstructure that occurs during aging. The most well-known and widely observed changes are coarsening of the Ag3Sn and Cu6Sn5 intermetallic compounds (IMCs) present in the eutectic regions between beta-Sn dendrites. In our prior investigation, we have developed new procedures to study the coarsening of IMC Particles that occur in a small fixed region of a SAC305 solder joint sample after several durations of aging. Scanning Electron Microscopy (SEM) has been utilized to examine aging induced coarsening of IMCs occurring within lead free solders. To identify the fixed region of interest for subsequent SEM imaging, a nanoindentation system was used to make small markers at the corners of the studied region in the solder joint sample. The markers were used to position the sample and locate the same region of the microstructure precisely. In the current work, we have extended our prior study to examine microstructural evolution in SAC305 lead free alloys for both short and long term aging experiments. Samples were formed with reflowed cooling profiles and resulting initial microstructures, and then polished microscopy cross-sections were prepared. For short term aging experiments, the microstructures were observed and recorded in the selected regions after every one hour of aging exposures using Scanning Electron Microscopy (SEM). For long term aging experiments, the microstructures of the several fixed regions of interest were recorded every 250 hours. After each aging time, we were able to quantitatively analyze the evolution of Ag3Sn and other IMCs with aging. Specifically, the aging induced changes in number of IMCs, total area of all IMCs, average area of a particle, average diameter of a particle and the normalized diameter were quantified in the fixed regions. Quantitative analysis results show that the number of IMC particles decreases while the average diameter of the particles increases significantly (more than 300%) with increasing aging time. With that being said, the most of the changes in the microstructure were found to occur within first 250 hours of aging. Finally, empirical models describing the growth of IMC particles with aging were examined and applied to our experimental data.
Microbiological Quality and Risk Assessment for Aflatoxins in Groundnuts and Roasted Cashew Nuts Meant for Human Consumption

Nuts are one of the commonly consumed snacks but poor handling and storage practices can make them prone to foodborne infections. The study aimed at assessing the microbiological quality and risk assessment for aflatoxins in groundnuts and cashew nuts consumed in selected locations in Nigeria. The moisture content, colony counts, incidence of pathogenic bacteria, aflatoxin contamination, and risk assessment for aflatoxins were evaluated using standard methods. The moisture content and total viable count ranged from 5.00–8.60% and 5.5–89 × 103 cfug−1, respectively, while the fungal count was between 4–24 × 103 and 1.0–4.5 × 102 cfug−1, respectively. Eleven fungal species belonging to 5 genera were isolated from the nuts, with Aspergillus flavus, Rhizopus oryzae, and Fusarium oxysporum having the highest percentage occurrence of 50%. In addition, the aflatoxin concentration ranged 0.1–6.8 and 29–33.78 ng kg−1 for cashew nuts and groundnuts, respectively. The margin of exposure (MOE) to aflatoxin contamination was 6.10 for groundnuts and 1000 for cashew nuts and the nuts consumers were at a risk of exposure to foodborne diseases and aflatoxin contamination with mean exposure values of 27.96 and 0.17 ng kg−1bwday−1, respectively. The risk of primary liver cancer for groundnuts and cashew nuts consumers was also estimated to be 1.38 and 0.01 canceryear−1100,000−1person, respectively. This calls for mitigation measures from appropriate governmental organizations.
Protein Sensing Beyond the Debye Length Using Graphene Field-Effect Transistors

Sensing biomolecules in electrolytes of high ionic strength has been a difficult challenge for field-effect transistor-based sensors. Here, we present a graphene-based transistor sensor that is capable of detection of antibodies against protein p53 in electrolytes of physiological ionic strength without dilution. As these molecules are much larger than the Debye screening length at physiological ionic strengths, this paper proves the concept of detection beyond the Debye length. The measured signal associated with the expected specific binding of the antibodies to p53 is concluded to result from resistance changes at the graphene-electrolyte interface, since a sensor responding to resistance changes rather than charge variations is not limited by Debye screening. The conclusion with changes in interface resistance as the underlying phenomena that lead to the observed signal is validated by impedance spectroscopy, which indeed shows an increase of the total impedance in proportion to the amounts of bound antibodies. This finding opens up a new route for electrical detection of large-size and even neutral biomolecules for biomedical detection applications with miniaturized sensors.
Combining Immune Checkpoint Inhibitors With Conventional Cancer Therapy

Immune checkpoint inhibitors (ICIs) have recently revolutionized cancer treatment, providing unprecedented clinical benefits. However, primary or acquired therapy resistance can affect up to two-thirds of patients receiving ICIs, underscoring the urgency to elucidate the mechanisms of treatment resistance and to design more effective therapeutic strategies. Conventional cancer treatments, including cytotoxic chemotherapy, radiation therapy, and targeted therapy, have immunomodulatory effects in addition to direct cancer cell-killing activities. Their clinical utilities in combination with ICIs have been explored, aiming to achieve synergetic effects with improved and durable clinical response. Here, we will review the immunomodulatory effects of chemotherapy, targeted therapy, and radiation therapy, in the setting of ICI, and their clinical implications in reshaping modern cancer immunotherapy.
Investigation of Polarization Weight -an Efficient Construction for Polar Codes

Polarization weight (PW) is a novel construction method for polar codes, which results in universal reliability ordering efficiently and yields imilar performance as other channel dependent construction methods. In this paper, we interpret PW method or algorithm from a rate allocation perspective of channel polarization to show its effectiveness. Take the AWGN channel as an example, we show that the rate allocation for information bits by PW method coincides with the capacities of channel polarization. Furthermore, some properties of PW algorithm, including the universal and fractal of the reliability ordering, are illustrated, which facilitate the implementation in practice. Comprehensive simulation results with various code rates, code lengths and list sizes are also shown to validate the effectiveness of PW method.
Low-profile end-fire phased array with omni-directional scanning characteristics

A low-profile end-fire phased array with omnidirectional scanning characteristics is presented in this paper. The antenna consists of novel omnidirectional radiating elements to realize 360° scanning in azimuth plane in over 20% bandwidth (VSWR<2), while the total height of array is only 0. 054λ0 (λ0 denotes the free-space wavelength corresponding to the center operating frequency). An 8×8 finite array is simulated using commercial software to validate the performance of the finite array. The edge effect of the finite array is discussed. Numerical results show that the proposed low-profile end-fire phased array has good omnidirectional scanning characteristics in azimuth plane.