Miracle-dz/UniFAR-FTUs huggingface dataset:
"Doing TIME in Athens": A Photovoice Journey With Adolescents in Search of Social Change and the Unintended Benefit of Positive Mental Health Outcomes

"Doing TIME (This Is My Environment) in Athens" was a photovoice project involving a group of adolescents from the town of Athens, Georgia. The purpose of the "TIME" study was to use photovoice methodology to teach participating young people how to enact social change in their community. Participants were charged with taking photographs that best represented (a) what they liked about their community and (b) what they would like to see changed. Participants took a total of 67 photographs; these were methodically narrowed down to 26 photographs using a combination of open-ended discussion questions and semistructured interview questions. The final photographs represented five themes: (a) economic injustice, (b) segregation by race and class, (c) animal rights and neglect, (d) love of the arts, and (e) a sense of belonging and pride. These photographs were then captioned, framed, and displayed at a local historic art gallery, where local residents, university officials, and policy-makers were invited to discuss the youth photographers’ concerns.
Experience with transformer diagnostics based on dielectric response measurements in time domain

The paper presents results of diagnostic measurements on different transformers performed in time domain. New approaches for interpretation of the results are proposed and discussed. Modelling and calculations of different diagnostic values including dielectric response function are provided. Streszczenie. W artykule opisano wyniki badań diagnostycznych transformatorów metodą odpowiedzi dielektrycznej w dziedzinie czasu. Zaproponowano nowy sposób interpretacji uzyskanych wyników. Opisano sposób modelowania i obliczania parametrów diagnostycznych funkcji odpowiedzi dielektrycznej. (Doświadczenia z badań diagnostycznych transformatorów metodą odpowiedzi dielektrycznej w dziedzinie czasu).
Joint Communications and Sensing Using Millimeter Wave Networks: A Bonus SAR

In modern cellular communication networks, higher density of base stations and higher frequency bands will be employed. If being reflected by targets in the environment, the scattered communication signal also brings back the information of the targets, in addition to the communication messages, to the receivers. In this paper, it is proposed to leverage the reflected communication signals to reconstruct the image of the illuminated region. Due to the analogy to traditional synthetic aperture radar (SAR), the principle of spotlight SAR, namely the tomography via Fourier transformation, is adopted with necessary improvements. Numerical simulations are carried out to demonstrate the proposed algorithms.
Impact of Different Clinical Conditions of Preterm Infants on Parental Stress

Only a few studies report the impact of different clinical conditions of preterm infants on parental stress.Ninety parents of middle to late preterm infants filled out the parent distress subscale of the Parenting Stress Index-short form when their children were 1 month old. The scores were compared based on five clinical conditions of preterm infants: Condition 1: infants whose disease occurred before or during delivery; Condition 2: infants whose disease occurred after delivery; Condition 3: infants whose mother had a disease that might induce preterm birth or infant morbidity; Condition 4: infants with infectious disease; Condition 5: infants with respiratory distress. Parental distress scores in different demographic and clinical conditions was compared.The stress of parents worsen when preterm infants had a disease occurred before and during delivery. In contrast, there was no impact when infant had a disease occurred after delivery. The stress of parents worsened when the preterm infants had respiratory distress. In contrast, there was no impact when infant had an infectious disease. When there was a maternal disease that may induce preterm birth or disease in infants, parental stress would worsen.The risk factors mentioned above increased parental stress as early as 1 month after delivery. Finding the risk factor as early as possible, and then performing a nursing intervention is crucial to decrease parents’ stress when they had preterm infants.
Analytical Modeling of Process Damping in Machining

The machining process induced damping caused by the indentation of the cutting edge into the wavy cut surface greatly affects the process stability in low-speed machining of thermally resistant alloys and hardened steel, which have high-frequency vibration marks packed with short wavelengths. This paper presents an analytical model to predict the process damping forces and chatter stability in low-speed machining operations. The indentation boundaries are evaluated using the cutting edge geometry and the undulated surface waveform. Contact pressure due to the interference of the rounded and straight sections of the rigid cutting edge with the elastic-plastic work material is analytically estimated at discrete positions along the wavy surface. The overall contact pressure is obtained as a function of the cutting edge geometry, vibration frequency and amplitude, and the material properties of the workpiece. The resulting specific indentation force is evaluated by integrating the overall pressure along the contact length. Then, the process damping force is linearized by an equivalent specific viscous damping, which is used in the frequency domain chatter stability analysis. The newly proposed analytical process damping model is experimentally validated by predicting the chatter stability in orthogonal turning, end milling, and five-axis milling of flexible blades. It is shown that the proposed model can replace currently used empirical models, which require extensive experimental calibration approach or computationally prohibitive finite elements based numerical simulation methods.
Cluster based Online Task Assignment for Mobile Crowdsensing

Mobile crowdsensing has become a promising sensing paradigm with the popularization of mobile devices. In this paper, we focus on an opportunistic mobile crowdsensing scenario where there are multiple task requesters and users, who move in an opportunistic way in the target environment. When a task requester encounters a user, he can assign some of his held tasks to the user and receive corresponding task results when they re-encounter sometime later. In this paper, we study how to minimize the largest makespan of all requesters for the task result collections. To address this issue, we propose a cluster based largest makespan sensitive online task assignment (C-LOTA) algorithm. C-LOTA first performs two-phase clustering which clusters the users into different clusters, one for each task requester, based on their relativeness to the task requesters and also the task workloads at different requesters. C-LOTA then iteratively performs greedy intra-cluster task assignment such that largest task is firstly assigned and the first idle user always takes the task, until all tasks are assigned. We present the detailed algorithm design of C-LOTA. We deduce its computation complexity. Simulation results show that C-LOTA can achieve much better performance compared with existing work.
New fourfolds from F‐theory

In this paper, we apply Borcea–Voisin's construction and give new examples of fourfolds containing a del Pezzo surface of degree six, which admit an elliptic fibration on a smooth threefold. Some of these fourfolds are Calabi–Yau varieties, which are relevant for the N=1 compactification of Type IIB string theory known as F‐theory. As a by‐product, we provide a new example of a Calabi–Yau threefold with Hodge numbers h1,1=h2,1=10 .
Edge-Based NILM System with MDMR Filter-Based Feature Selection

Non-intrusive load monitoring (NILM) leverages disaggregation algorithms to obtain appliance-level power consumption from the mains measurement. Coupled with edge computing, NILM can realize real-time load disaggregation, as well as energy conservation and privacy protection. However, the high feature dimensionality and complex disaggregation algorithm of NILM are both memory-demanding in terms of the edge devices. In this paper, we propose an edge-based NILM system, with a Raspberry-based edge device as validation. To address the memory demand problem, we propose a novel feature selection method based on max-discrimination and min-redundancy (MDMR) filter, which not only reduces the feature space, but also improves the classification performance. Meanwhile, several typical supervised algorithms are trained and compared to determine an optimal solution with the best disaggregation performance and least algorithm complexity. The evaluation results reveal that the MDMR filter-based feature selection enables our e-NILM system with 64.29% feature space reduction and 97.12% accuracy.
PrecipLSTM: A Meteorological Spatiotemporal LSTM for Precipitation Nowcasting

Accurate and timely nowcasting precipitation has huge social and economic benefits. However, the changes in clouds including expansion, dissipation, and distortion are extremely complex, which exacerbates the difficulty of forecasting. Fortunately, it still follows certain meteorological laws, which can be explored based on spatiotemporal information but are not fully considered by previous models. In this article, we design two modules to focus on these messages based on atmospheric characteristics. Specifically, the spatial local attention memory (SLAM) module combines local attention and memory mechanism to capture the meteorological spatial relationship, while the time difference memory (TDM) module combines differential technology and memory mechanism to capture the meteorological temporal variants. We combine these two modules with PredRNN and propose PrecipLSTM to sufficiently capture the spatiotemporal dependencies of radar data. We do exhaustive experiments with five baselines on four radar datasets. It is verified that PrecipLSTM achieves state-of-the-art results with fewer parameters than the previous state-of-the-art method.
Characterisation of hollow-core photonic bandgap fibres and other multimode fibres for optical communications

Progress in multimode fibre technology has opened diverse opportunities in science and technology, one of which is pushing data capacities beyond the fundamental limits of conventional single-mode fibre, so as to avert network gridlock precipitated by exponentially growing global traffic demands. Hollow-core photonic bandgap fibres (HC-PBGFs), where light propagates in air rather than glass, have been considered as a potential candidate for high-capacity telecommunications applications, while offering superior performance over solid-core fibres in terms of low loss, low latency, and ultralow nonlinearity. This thesis presents research conducted as part of the efforts of the EU FP7 project MODE-GAP to pioneer developments in HC-PBGF and related space-division multiplexing technologies. This work is involved with the characterisation of primarily HC-PBGFs and also solid-core multimode fibres, recently and respectively fabricated through the facilities of the Optoelectronics Research Centre and other project partners. A time-of-flight method is applied to make extensive measurements on these fibres to study their modal properties, including mode coupling and differential modal delay, in order to assess their capabilities for single-mode as well as mode-division multiplexed data transmission. In support of the fibre design process, this work has aided the full characterisation of the first ever fabricated 37-cell HC-PBGFs and enabled subsequent mode-division multiplexing trials at a record capacity of 73.7 Tbit/s. Characterisation of multi-kilometre record-length HC-PBGFs is also performed, and has supported the demonstration of these fibres in metro network environments. To further understand the modal processes and facilitate fibre improvement, a simulation environment is constructed based on a power coupling propagation model. This has enhanced interpretations of experimental time-of-flight data, as well as validated a proposed theory relating mode coupling and loss in HC-PBGFs. Finally, an experimental technique is introduced to inspect longitudinal defects in solid- and hollow-core fibres, by applying time-of-flight principles.
Exploiting Sparse Millimeter Wave Hotspots in Two-Tier Heterogeneous Networks: A Mobility-Enabled Pushing Scheme

Millimeter wave (mmWave) communications has attracted significant attention due to its potential for providing very large bandwidths. Unfortunately, the propagation of millimeter waves suffers from severe path loss and blocking, which limits the coverage of mmWave systems. To overcome this, mmWave hotspot empowered two-tier heterogeneous networks are expected to play an important role in the sixth generation (6G) of mobile communication systems. When the deployment of mmWave hotspots is not dense enough, or even sparse, assuring the quality of service (QoS) for mobile users becomes rather challenging. In this paper, we present a mobility-enabled pushing scheme, in which popular content items are cached by a mobile user when he/she can be served by an mmWave hotspot. Optimal pushing policies with statistical mobility models and predeter-mined trajectories are presented and analyzed respectively. Both theoretical and numerical results demonstrate the substantial caching gain due to user mobility in mmWave hotspot empowered two-tier networks.
Exploring the Characteristics, Drivers and Control Strategies of Informal Settlements on Mkimbizi Hill in Iringa Municipality, Tanzania

This study explored the characteristics, drivers, and control strategies of informal settlements on MkimbiziHill in Iringa Municipality, Tanzania. The study employed a mixed research design whereby heads ofhouseholds were randomly selected while key informants were purposively sampled. Data were collectedthrough a questionnaire survey with heads of households, in-depth interviews with key informants, and fieldobservations. Quantitative data were analysed by statistical product and service solution software.Qualitative data were organised into themes and involved content analysis. It was established that the studyarea is occupied by individuals of different social and economic characteristics with informal land tenure,limited access to social services, and are exposed to the risk of the collapse of buildings and rockfalls. Thestudy also found that informal settlements in the study area were caused by the lack of education on urbansettlements, proximity to essential social services, cheap plots, and poor settlement planning. Nonetheless, thestudy showed that the strategies used to control informal settlements in the study area included intermittentpatrol, awareness creation on sustainable urban development, and settlements for economically weakindividuals. The study recommends proper land use planning for sustainable urban development by theauthorities.
Rotordynamics modelling and analysis of high-speed permanent magnet electrical machine rotors

For the high-frequency permanent magnet electrical machine, a reasonable mechanical aspect design is crucial to meet its stability and reliability. This study focuses on the accurate modelling and analysis of the natural frequencies and modes of the rotor assembly for a designed and manufactured 100 kW 32,000 r/min motor. The influence of contact stiffness and friction on bending frequencies is analysed in detail. To obtain the accurate results of first two bending frequencies, on the basis of the finite-element method, the optimisation method is carried out to acquire appropriate variables of the contact stiffness and friction. The optimised results show that the method proposed in this study can realise the accurate analysis of the rotor mode, which are verified by free-free modal testing of the rotor.
Research on the Neutral-Point Voltage Balance for NPC Three-Level Inverters under Non-Ideal Grid Conditions

In order to solve the neutral-point voltage unbalancing problem for neutral-point clamped (NPC) three-level inverters under non-ideal grid conditions, a novel zero-sequence component injection method for modulation signals was proposed in this paper. Based on the mathematical expressions of neutral-point voltage unbalancing, the fluctuation of the neutral-point voltage under different grid conditions was studied. The proposed method dynamically calculates the zero-sequence component for modulation signals by region selections based on sinusoidal pulse width modulation (DCR-SPWM). Under non-ideal grid conditions, this DCR-SPWM method can control the neutral-point voltage balance for NPC three-level inverters with different grid and output power conditions, and improves the grid current quality. The simulation results verified the correctness of the theoretical analysis in this paper, and the feasibility and effectiveness of this method were verified by the experiments in the experimental platform of the NPC three-level grid-connected inverter based on DSP-CPLD controllers.
Suppression of Self-Noise Feedback in GAMP for Highly Correlated Large MIMO Detection

This paper deals with uplink multi-user detection (MUD) via generalized approximate message passing (GAMP) in highly correlated large multi-user multi-input multi-output (MUMIMO) systems. The most vital mechanism of GAMP is Onsager correction for decoupling the self-noise feedback of beliefs across iterations; this makes it possible to exchange extrinsic values. First, we show that by introducing the belief scaling method proposed in the context of Gaussian belief propagation (GaBP) for adjusting the convergence speed into GAMP, the Onsager correction works properly even under spatial fading correlation, which significantly improves detection capability. Surprisingly, the performance is much better compared to that of the GaBP with belief scaling, and even asymptotically approaches that of computationally expensive expectation propagation (EP) detectors. Based on the results, we clarify why such a dramatic performance improvement is possible only for GAMP in terms of the suppression mechanism of self-noise feedback.
Simulated contribution of the interdecadal Pacific oscillation to the west Eurasia cooling in 1998–2013

Large ensemble simulations with six atmospheric general circulation models involved are utilized to verify the interdecadal Pacific oscillation (IPO) impacts on the trend of Eurasian winter surface air temperatures (SAT) during 1998–2013, a period characterized by the prominent Eurasia cooling (EC). In our simulations, IPO brings a cooling trend over west-central Eurasia in 1998–2013, about a quarter of the observed EC in that area. The cooling is associated with the phase transition of the IPO to a strong negative. However, the standard deviation of the area-averaged SAT trends in the west EC region among ensembles, driven by internal variability intrinsic due to the atmosphere and land, is more than three times the isolated IPO impacts, which can shadow the modulation of the IPO on the west Eurasia winter climate.
Optimal design of LCL filter in grid‐connected inverters

As an essential part in technologies for energy storage systems (ESSs) or renewable energy systems (RESs), grid-connected inverters need power passive filters to meet grid regulations. As typical passive filters, L filter and LCL filter are employed. Although LCL filter is more cost-effective than L filter, a design of LCL filter is more complicated than L filter. LCL filter has three filter elements: inverter-side inductor, grid-side inductor, and filter capacitor. To design the three elements for LCL filter, three or more simultaneous equations should be required, which means that three or more design target should exist. Since conventional design methods for LCL filter do not suggest clear targets and do follow try & error method which cannot be matched exactly with design targets, the conventional methods cannot be optimal design. In this study, a filter inductance ratio to minimise total filter inductance, a filter admittance to meet grid regulation and characteristic impedance for low current stress of switch stack are suggested as design goals. Optimal design equation is proposed to meet the three design goals. The proposed method can solve unique filter elements for LCL filter without iterative try & error. The design method is evaluated through simulation and experiment.
Double Sparsity-Based Joint Active User Detection and Channel Estimation for mMTC-Enabled Massive MIMO

In this paper we investigate the problem of joint active user detection (AUD) and channel estimation (CE) in massive machine-type communications (mMTC) scenario with a massive multiple-input multiple-output (MIMO) base station. Besides sporadic traffic of massive access, the block sparsity of angular domain channel in massive MIMO is additionally considered to reduce the pilot overhead. By formulating the joint AUD and CE problem by sparse Bayesian learning with the double-sparsity feature in the angular domain, we introduce the modified pattern-coupled prior model to capture the non-uniform block structure. Then an algorithm based on variational Bayesian inference is proposed to recover the angular-domain channel. Moreover, a novel AUD scheme using the recovered angular-domain channel is developed by exploiting the high array gain in massive MIMO systems. Numerical results demonstrate that our proposed method can significantly improve the channel estimation quality and detection accuracy especially in the low pilot-length region.
A Semi Empirical Regression Model for Critical Dent Depth of Externally Corroded X65 Gas Pipeline

External corrosion dent is a common type of compound dent. On the one hand, this type of compound dent reduces the bearing area and bearing capacity of the pipeline. On the other hand, it leads to an increase in the stress–strain concentration in the dent and reduces the anti-fatigue load capacity of the pipeline, which is more harmful to the service safety of the pipeline than the simple dent. In this study, the reliability of the modeling method was verified by the numerical inversion of the full-size dented pipe test. A three-dimensional finite element model for a pipe with a small corrosion dent was established by analyzing the internal detection data on corrosion defects of pipes with a diameter of 813 mm. The failure criterion of the corrosion dent pipe and the calculation method of the critical dent depth were determined. The influence of corrosion depth, length, width, internal pressure load, curvature radius of indenter, and diameter–thickness pipeline ratio on critical dent depth was investigated. Finally, a critical dent-depth prediction formula was developed based on the numerical results. This study provides a reference and significant guidance for the applicability evaluation of corroded sunken pipelines.