Miracle-dz/UniFAR-FTUs huggingface dataset:
Closed-Loop Sparse Channel Estimation for Wideband Millimeter-Wave Full-Dimensional MIMO Systems

This paper proposes a closed-loop sparse channel estimation (CE) scheme for wideband millimeter-wave hybrid full-dimensional multiple-input multiple-output and time division duplexing based systems, which exploits the channel sparsity in both angle and delay domains. At the downlink CE stage, random transmit precoding matrix is designed at base station (BS) for channel sounding, and receive combining matrices at user devices (UDs) are designed whereby the hybrid array is visualized as a low-dimensional digital array for facilitating the multi-dimensional unitary ESPRIT (MDU-ESPRIT) algorithm to estimate respective angle-of-arrivals (AoAs). At the uplink CE stage, the estimated downlink AoAs, namely, uplink angle-of-departures (AoDs), are exploited to design multi-beam transmit precoding matrices at UDs to enable BS to estimate the uplink AoAs, i.e., the downlink AoDs, and delays of different UDs, whereby the MDU-ESPRIT algorithm is used based on the designed receive combining matrix at BS. Furthermore, a maximum likelihood approach is proposed to pair the channel parameters acquired at the two stages, and the path gains are then obtained using least squares estimator. According to spectrum estimation theory, our solution can acquire the super-resolution estimations of the AoAs/AoDs and delays of sparse multipath components with low training overhead. Simulation results verify the better CE performance and lower computational complexity of our solution over state-of-the-art approaches.
Alterations in Cutaneous Vasomotor Regulation during Acute and Chronic Hypoxia

Abstract : The effects of acute and chronic hypoxic exposure on peripheral skin blood flow were examined in six naive subjects by measuring skin blood flow in the right index finger with a laser doppler velocimeter. After baseline skin blood flows were determined, measurements of the vasoconstrictor responses to breath holding (BH), Valsalva maneuver (VM), and cold pressor test (CPT) employing ice water immersion of the contralateral hand were made. Subjects were first tested at sea level (SL), after two-hour exposure to a simulated altitude (SA) of 4300 meters (445 torr), and then tested on days 2, 3, 5, and 8 during chronic exposure at Pikes Peak, Colorado (4300 meters). Baseline and vasoconstrictor responses were not significantly altered by acute hypobaric exposure. However, during days 2-5 of chronic exposure there were significant falls in baseline peripheral skin blood flow. Similar reductions were also found in vasomotor responsiveness on days 2-5 but had recovered by day 8.
A New Transformer-Less Five-Level Grid-Tied Inverter for Photovoltaic Applications

A new fundamental structure of a single-phase transformer-less grid connected multilevel inverter based on a switched-capacitor structure is presented in this study. By employing the series-parallel switching conversion of the integrated switched-capacitor module in a packed unit, attractive features for the proposed inverter can be obtained such as high efficiency and boosting ability within a single stage operation. Also, using a common grounding technique provides an additional advantage of reducing the leakage current. Moreover, the presented structure generates a multilevel waveform at the output voltage terminals which reduces the harmonics in the system. A peak current controller is utilized for triggering the gate of the power switches and controlling both the active and reactive powers. This results in a tightly controlled current with an appropriate quality that can be injected to the grid using a single source renewable energy resource. Operating procedures, design considerations, comparison studies and test results of a 620 W prototype are also presented to validate the accuracy and feasibility of the proposed multilevel inverter.
What’s going on down under? Part 1: Portrayals of culture in award-winning Australian young adult literature

Books published in Australia are strong choices for youth collections in other English-speaking countries because of the shared language and the use of different vocabulary and cultural expressions, enlisting readers to think critically about meaning and context. This article is the second in a two-part series exploring portrayals of culture in two popular Australian young adult literature awards: the Children’s Book Council of Australia’s (CBCA) Book of the Year: Older Readers, chosen by adults, and the Centre for Youth Literature’s Gold Inky Awards, chosen by young adults. Using a critical content analysis approach, the research examined the twenty-four winners from 2007 to 2018 for depictions of nine cultural constructs including class, disability, gender, immigration, Indigenous Australians, language, the LGBTQIA community, race/ethnicity/nationality, and religion. Findings suggest that class is an ever-present cultural element in the titles, especially in the CBCA award winners, and issues of class privilege and disadvantage are linked to other constructs, notably gender, immigration, language, and race/ethnicity/nationality. While two titles portrayed Indigenous Australians authentically, this construct was the least represented in the sample and reflects a gap in the awards and Australian youth publishing overall, as noted by other researchers. These titles offer an alternative perspective to issues affecting young adults on a global level such as immigration, racism, and sexism.
Sample Size Calculations for Cluster Randomised Trials

Objectives: Cluster randomised trials, in which groups of individuals are randomised, are increasingly being used in the health field. Adopting a clustered approach has implications for the design of such trials, and sample size calculations need to be inflated to accommodate for the clustering effect. Reliable estimates of intracluster correlation coefficients (ICCs) are required for robust sample size calculations to be made; however, little empirical evidence is available on their likely size, and on factors which influence their magnitude. The aim of this study was to generate empirical estimates of ICCs and to explore factors which may affect their magnitude. Methods: Empirical estimates of ICCs were calculated for both process variables and patient outcomes from a number of datasets of primary and secondary care implementation studies. Results: Estimates of ICCs varied according to setting and type of outcome. Estimates of ICCs for process variables were higher than those for patient outcomes, and estimates derived from secondary care were higher than those from primary care. ICCs for process variables in primary care were of the order of 0.05–0.15, whilst those in secondary care were of the order of 0.3. Estimates for patient outcomes in primary care were generally lower than 0.05. Conclusions: Adopting cluster randomisation has implications for the design, size and analysis of clinical trials. This study gives an insight into the potential size of ICCs in primary and secondary care, and provides a practical guide to researchers to aid the planning of future studies in this area.
Comparison of Electrical Breakdowns Produced by a Nanosecond High-Voltage Pulse Applied to Metallic and Composite Material Electrodes

In this article, the effect of electrode material on the electrical breakdown, produced by a 500-ns duration high-voltage pulse in dry air at atmospheric pressure, is investigated. The configuration chosen is a pin-to-plane geometry with a gap distance of 2 mm. Both polarities of the high-voltage pulse have been investigated for three different pin electrodes. The reference pin is a copper wire of 50 mm length, while the two other pins are made of a highly resistive composite material of 240 $\text{k}\Omega $ /m, with two different lengths of 50 and 500 mm. The plane electrode is a tungsten plate of 3 cm diameter. The discharges obtained for the highly resistive wires (HRWs) can be categorized as resistive barrier discharges. Both electrical and optical characteristics of the discharges are presented and discussed. The current, voltage, and energy deposition are first analyzed. Then, the time-resolved phase-locked images of the discharges are presented, showing the propagation of the discharge filaments in the gap. The experimental results demonstrate a strong influence of the electrode material on the discharge characteristics, regardless of the polarity of the applied voltage. The main finding is that, for the same applied high-voltage pulse, the use of highly resistive materials significantly reduces the energy deposition into the discharge and the light emission from the discharge.
PerHelper: Helping Developers Make Better Decisions on Permission Uses in Android Apps

Permission-related issues in Android apps have been widely studied in our research community, while most of the previous studies considered these issues from the perspective of app users. In this paper, we take a different angle to revisit the permission-related issues from the perspective of app developers. First, we perform an empirical study on investigating how we can help developers make better decisions on permission uses during app development. With detailed experimental results, we show that many permission-related issues can be identified and fixed during the application development phase. In order to help developers to identify and fix these issues, we develop PerHelper, an IDEplugin to automatically infer candidate permission sets, which help guide developers to set permissions more effectively and accurately. We integrate permission-related bug detection into PerHelper and demonstrate its applicability and flexibility through case studies on a set of open-source Android apps.
Brainglance: Visualizing Group Level MRI Data at One Glance

The vast majority of studies using functional magnetic resonance imaging (fMRI) are analyzed on the group level. Standard group-level analyses, however, come with severe drawbacks: First, they assume functional homogeneity within the group, building on the idea that we use our brains in similar ways. Second, group-level analyses require spatial warping and substantial smoothing to accommodate for anatomical variability across subjects. Such procedures massively distort the underlying fMRI data, which hampers the spatial specificity. Taken together, group statistics capture the effective overlap, rendering the modeling of individual deviations impossible – a major source of false positivity and negativity. The alternative analysis approach is to leave the data in the native subject space, but this makes comparison across individuals difficult. Here, we propose a new framework for visualizing group-level information, better preserving the information of individual subjects. Our proposal is to limit the use of invasive data procedures such as spatial smoothing and warping and rather extract regional information from the individuals. This information is then visualized for all subjects and brain areas at one glance – hence we term the method brainglance. Additionally, our method incorporates a means for clustering individuals to further identify common traits. We showcase our method on two publicly available data sets and discuss our findings.
Subsidence events in the Krafla area, North Iceland, 1975-1979

In the inflation-deflation sequence of the Krafla magma chamber since its beginning in 1975, 12 deflation or subsidence events have been identified until May, 1979. The tilt and distance measurements relating to these subsidence events are discussed in some detail. All of these subsidence events are associated with horizontal magma flow along the N-S trending fissure zone, which goes through the central part of the Krafla caldera, to form a dike 3 to 5 m wide, 80 km long, and 1.0 to 2.5 km high from the bottom to the top. The total volume of magma, which flowed out of the Krafla magma chamber during these 12 events, is estimated as 481 x 106 m3 , whereof 407 x 106 m 3 are estimated to have flowed northwards, 72 x 106 m3 southwards and about 2 x 106 m 3 came to the surface as basaltic lava.
A stable interface‐enriched formulation for immersed domains with strong enforcement of essential boundary conditions

Generating matching meshes for finite element analysis is not always a convenient choice, for instance, in cases where the location of the boundary is not known a priori or when the boundary has a complex shape. In such cases, enriched finite element methods can be used to describe the geometric features independently from the mesh. The Discontinuity‐Enriched Finite Element Method (DE‐FEM) was recently proposed for solving problems with both weak and strong discontinuities within the computational domain. In this paper, we extend DE‐FEM to treat fictitious domain problems, where the mesh‐independent boundaries might either describe a discontinuity within the object, or the boundary of the object itself. These boundaries might be given by an explicit expression or an implicit level set. We demonstrate the main assets of DE‐FEM as an immersed method by means of a number of numerical examples; we show that the method is not only stable and optimally convergent but, most importantly, that essential boundary conditions can be prescribed strongly.
The limit property of a risk model based on entrance processes

Abstract In this article, we investigate the risk model based on an entrance process with stochastic investment, where an insurance company invest risky stock market with a geometric Brownian motion, and risk-free market. Under the assumptions that the entrance process is a renewal process and the claims sizes are pairwise strong quasi-asymptotically independent, which belong to the different heavy-tailed distribution classes,the finite-time and infinite-time asymptotic estimates of the risk model with stochastic investment are obtained.
Interprofessional working : cultures, identities and conceptualisations of practice

The relationship between poor interprofessional working and child tragedies has been made apparent by numerous inquiries into child deaths. In seeking to address the well documented problems of professional communication, cooperation and collaboration; transformation in the structure (Children's Trusts) and delivery of services (integrated teams) for children and young people was initiated under the UK New Labour government (DfES, 2004). Focused on early interventions to meet the additional needs of children, the Common Assessment Framework brings together professionally and vocationally qualified practitioners from statutory, public and voluntary agencies. This research charts the origins and evolution of interprofessional practice in the context of children and young people highlighting historically important cases. Key developments in the legislative, social and cultural contexts and the effects of their interactions are scrutinised to aid further understanding of present day structures and practice. Semi-structured interview data was analysed to generate themes at individual and practitioner group level. Utilisation of the qualitative methodology Interpretative Phenomenological Analyses supported identification of three super-ordinate themes: Roles, Identities and Relationships, Change and Adaptation and Conflict and Contradictions. Theoretical connections with the literature on identity are explored providing insight into objectives, learning and new forms of practice. Drawing on ideas from Cultural Historical Activity Theory the implications for policy and practice are assessed. The thesis answers the call for the greater application of theory to interprofessional working (IPW) and education (IPE) contexts. Furthermore the research prioritises the perspective of the practitioner generating greater understanding of what it means to work collaboratively. Research findings pertain to the double binds experienced by practitioners which impeded collaboration but also generated unexpected innovations in practice and the identification of different practice orientations amongst professionally and vocationally qualified practitioners. The research concludes by asserting that partnership and child centred practice are being distorted by a performance culture.
Expanding our understanding of the role of peer support in child welfare workforce retention

ABSTRACT Turnover is problematic for child welfare agencies and clients. To better understand the role of peer support in retention among caseworkers, this study explored whether staff perceive distinct types of peer support (operational and social-emotional) and examined the extent to which peer support differs by demographic and organizational factors in predicting intent to stay. Results from 1,703 caseworkers indicated that they perceive both types of peer support; both types are associated with job satisfaction, organizational climate, and intent to stay. Strategies to bolster peer support and opportunities for future research are discussed.
Interferometric Imaging and its Application to 4D Imaging

Interferometric Imaging and its Application to 4D Imaging Mrinal Sinha This thesis describes new interferometric imaging methods for migration and waveform inversion. The key idea is to use reflection events from a known reference reflector to ”naturally redatum” the receivers and sources to the reference reflector. Here, ”natural redatuming” is a data-driven process where the redatuming Green’s functions are obtained from the data. Interferometric imaging eliminates the statics associated with the noisy overburden above the reference reflector. To mitigate the defocussing caused by overburden errors I first propose the use of interferometric least-squares migration (ILSM) to estimate the migration image. Here, a known reflector is used as the reference interface for ILSM, and the data are naturally redatumed to this reference interface before imaging. Numerical results on synthetic and field data show that ILSM can significantly reduce the defocussing artifacts in the migration image. Next, I develop a waveform tomography approach for inverting the velocity model by mitigating the velocity errors in the overburden. Unresolved velocity errors in the overburden velocity model can cause conventional full-waveform inversion to get stuck in a local minimum. To resolve this problem, I present interferometric full-waveform inversion (IFWI), where conventional waveform tomography is reformulated so a velocity model is found that minimizes the objective function with an interferometric crosscorrelogram misfit. Numerical examples show that IFWI, compared to FWI, computes a significantly more accurate velocity model in the presence of a nearsurface with unknown velocity anomalies. 5 I use IFWI and ILSM for 4D imaging where seismic data are recorded at different times over the same reservoir. To eliminate the time-varying effects of the near surface both data sets are virtually redatumed to a common reference interface before migration. This largely eliminates the overburden-induced statics errors in both data sets. Results with synthetic and field data show that ILSM and IFWI can suppress the artifacts caused by non-repeatability in time-lapse surveys. This can lead to a much more accurate characterization of the movement of fluids over time. In turn, this information can be used to optimize the extraction of resources in enhanced oil recovery (EOR) operations.
Inlining 3D Reconstruction, Multi-Source Texture Mapping and Semantic Analysis using Oblique Aerial Imagery

Abstract. This paper proposes an in-line method for the simplified reconstruction of city buildings from nadir and oblique aerial images that at the same time are being used for multi-source texture mapping with minimal resampling. Further, the resulting unrectified texture atlases are analyzed for fac¸ade elements like windows to be reintegrated into the original 3D models. Tests on real-world data of Heligoland/ Germany comprising more than 800 buildings exposed a median positional deviation of 0.31 m at the fac¸ades compared to the cadastral map, a correctness of 67% for the detected windows and good visual quality when being rendered with GPU-based perspective correction. As part of the process building reconstruction takes the oriented input images and transforms them into dense point clouds by semi-global matching (SGM). The point sets undergo local RANSAC-based regression and topology analysis to detect adjacent planar surfaces and determine their semantics. Based on this information the roof, wall and ground surfaces found get intersected and limited in their extension to form a closed 3D building hull. For texture mapping the hull polygons are projected into each possible input bitmap to find suitable color sources regarding the coverage and resolution. Occlusions are detected by ray-casting a full-scale digital surface model (DSM) of the scene and stored in pixel-precise visibility maps. These maps are used to derive overlap statistics and radiometric adjustment coefficients to be applied when the visible image parts for each building polygon are being copied into a compact texture atlas without resampling whenever possible. The atlas bitmap is passed to a commercial object-based image analysis (OBIA) tool running a custom rule set to identify windows on the contained fac¸ade patches. Following multi-resolution segmentation and classification based on brightness and contrast differences potential window objects are evaluated against geometric constraints and conditionally grown, fused and filtered morphologically. The output polygons are vectorized and reintegrated into the previously reconstructed buildings by sparsely ray-tracing their vertices. Finally the enhanced 3D models get stored as textured geometry for visualization and semantically annotated ”LOD-2.5” CityGML objects for GIS applications.
Variable Stiffness Spring Actuators for Low-Energy-Cost Human Augmentation

Theoretical studies suggest and experimental evidence confirms that maintaining and changing human joint stiffness by coactivated antagonistic muscles are metabolically expensive, even if muscles do not perform net mechanical work. Based on this observation, we posit that effective human augmentation can be achieved by actuators operated in parallel to human joints, even if these actuators only supplement joint stiffness without doing net mechanical work. In this article, we present a prototype variable-length leaf-spring actuator capable of large-range stiffness modulation. The key feature of the actuator is that it provides intrinsically low-energy-cost stiffness modulation even for large output deflection, by keeping the force on the driving motor low. Variable stiffness actuators use two motors to provide both stiffness and equilibrium position modulation as they are designed to do net mechanical work. The proposed actuator conceptually differs from variable stiffness actuators because first, it uses a single motor to only provide stiffness modulation, second, it does not provide equilibrium position modulation, and third, unless externally loaded, it cannot do net mechanical work. Using this actuator, we demonstrate stiffness augmentation during human–machine collaboration in challenging postural stabilization and weight-bearing tasks. Our results indicate that the proposed actuator can be used to complement a biological system by restoring or extending its functionality with low energy cost, and that variable stiffness spring actuators could effectively augment humans by doing no or a limited amount of mechanical work.