Miracle-dz/UniFAR-FTUs huggingface dataset:
Numerical Simulations of Turbulent Flows at Widely Different Mach Numbers

The present thesis mainly focuses on the numerical simulation of the turbulent flow field and acoustics developed in different industrial applications. The study covers a large range of Mach numbers, starting from incompressible regimes and ending with a fully compressible flow. In the first part of the thesis, several computations of an incompressible flow, are performed in order to study the behavior of an aircraft engine running close to the ground. The ground vortex interaction and particle ingestion are the investigated topics. The methods involved for solving the flow are the Reynolds Averaged Navier Stokes with a k-epsilon turbulence model closure, Large Eddy Simulation with Smagorinsky sub grid scale model. The particle ingestion problem is investigated using a one way coupling lagrangian particle tracking algorithm. The second part concerns the study of the flow around moving bodies and the acoustical field generated by it. Based on the flow incompressibility assumption, the problem is decoupled: first the flow solution is computed using Large Eddy Simulation frame work, then the acoustic sources are extracted and finally the acoustical wave propagation is studied using an acoustic analogy developed by Ffowcs-Williams and Hawkings. Three different cases are presented in the papers, all involving rotating bodies: an axial fan, a wind turbine and a propeller. From these three cases, only the wind turbine computation is presented in more detail in the thesis. The dynamics of a shock wave in a transonic flow in a channel are investigated in the third part of this thesis using the Large Eddy Simulation framework. Similar phenomena with those encountered in supersonic flows are found: Mach reflection shock wave, regular reflection shock wave, outlet pressure induced hysteresis, unsteady shock wave. (Less)
Teaching about Data and Databases

The panel on data(base) education at VLDB2021 [13] drew attention to important challenges in choosing how database classes are constructed for students in a world where data is being used in novel and impactful settings. This paper aims to present one view of a process for making these pedagogy decisions. We don't aim to present a best-possible design of the subject, rather we want to illuminate the space of possibilities, to encourage reasoned choices rather than simply teaching the subject as it was previously offered, or spending time on the latest innovations without considering the "opportunity cost" of doing so. We hope to guide the perplexed instructor or departmental curriculum committee.
The Social Technology and Research (STAR) Lab in the University of Hong Kong

The main goal of the Social Technology and Research Laboratory (STAR Lab) in the University of Hong Kong (https://star.hku.hk) is to develop novel IT technologies for serving the society. Our team has more than three years of experience in project development, web, app, and game design, photography, and video production. We are interested in? Data Science for Social Good", researching data-driven approaches that can benefit the public, NGOs, and the government.
Population Numbers of the Magellanic Penguin along Its Central-Southern Distribution in Argentina: An Update after 25 Years

Abstract. The overall population size and trend of the Magellanic Penguin (Spheniscus magellanicus) is uncertain and population estimates are available only for few locations. The last complete census along its central-southern distribution range in Argentina, province of Santa Cruz, was made in the 1990s. This study updates the breeding population size along Santa Cruz. Population estimates were compared with the last complete census, and trends were studied when it was possible. With 353,256 estimated breeding pairs, the overall population in Santa Cruz remained relatively stable after 25 years. The Santa Cruz population represents 31% of the Argentine Patagonian coast population and could represent between 22 and 30% of the species' global population. Colony sizes varied between 9 and 127,492 breeding pairs. Changes in abundance differed among locations, with individual colonies showing increasing, decreasing, or stable trends, which suggests that local factors determine population dynamics. The most significant increases (> 40%) were observed in the southern sector of Santa Cruz. Contrary to what was observed at the north of the distribution range in the province of Chubut, where trends of several colonies were inversely related to colony size, in Santa Cruz most of the largest colonies remained stable or even increased from the 1990s onwards.
Breeding Habitat Selection of the Daurian Redstart Phoenicurus auroreus at the Nest and Territory Scale

Abstract The Daurian Redstart Phoenicurus auroreus has expanded its breeding distribution in recent years and now breeds in Japan, previously only part of its wintering range. We analyzed the breeding habitat selection of the population at the nest and territory scale in the Kirigamine Highlands, Nagano, Central Japan. At the nesting scale, the birds chose buildings frequently occupied by humans, while at the territory scale, they avoided sites in larger built-up areas. Our findings demonstrate that the breeding habitat selection of Daurian Redstart is influenced by environmental factors at both nest and territory scales.
Temperature and Snow Depth Explain the Breeding Distribution Pattern of Yellow Bunting Emberiza sulphurata

Abstract Many bird species with heterogeneous distribution are at risk of extinction. It is essential to identify and elucidate environmental factors explaining such distribution patterns to develop effective conservation strategies for those species. Yellow Bunting Emberiza sulphurata is an endangered migrant bird species exhibiting heterogeneous breeding distribution in Japan. Here we clarify the spatial distribution and the altitudinal range of the Yellow Bunting breeding range, and detect environmental factors (e.g., climate and topography) influencing their distribution pattern using an extensive dataset from the national breeding birds survey of Japan. The presence of Yellow Bunting during the breeding season (1997–2002) and six environmental factors (temperature, snow depth, elevation, tertiary layer, landslide area and forest edge density) were analyzed using maximum entropy models (MaxEnt). We found that Yellow Buntings were present in a higher proportion of survey grids in northern Honshu (the main island of Japan) than elsewhere in the country, and they mainly occurred in areas below 700 m above sea level. Moreover, the elevation of the occupied grids decreased with latitude. Temperature and snow depth were of greater importance (0.380 and 0.350, respectively) than other factors in explaining the breeding distribution of the Yellow Bunting. Our study highlighted the location of the core areas of the Yellow Bunting's breeding distribution, and demonstrated that lower temperature and deeper snow cover are the critical determinants of those areas. There may be abundant prey and fewer avian competitors, such as resident bird species, in colder regions, and more frequent snow avalanches and water from melting snow may establish the marshy and bushy habitat preferred by Yellow Buntings. These findings are essential for developing effective conservation strategies for the endangered Yellow Bunting. As past mass-trapping may have also influenced the heterogeneous distribution of the Yellow Bunting, this is an important avenue for future research from a different perspective.
Effects of Rearing Methods on the Reproduction of Reintroduced Crested Ibis Nipponia nippon on Sado Island, Japan

Abstract An increasing number of reintroduction programs have been set up in recent years in an attempt to reintroduce once extinct species to their indigenous ranges and create self-sustaining populations. However, the released individuals often experience low mating success and fecundity. Appropriate rearing in captivity is considered essential for the successful post-release reproduction of captive-reared individuals. Low post-release mating success and fecundity are also issues in reintroduced Crested Ibis Nipponia nippon populations on Sado Island. These phenomena may be caused by the effects of hand-rearing in captivity, yet temporary hand-rearing is necessary when captive breeding, because rescuing embryos from mortality is essential due to the abnormal behavior of parent birds in captivity. Therefore, the establishment of rearing methods that temporarily protect embryos or chicks while limiting the negative effects of hand-rearing on breeding after release is needed. To overcome these challenges, we tested how captive rearing methods impact post-release courtship behavior, mating success, and fecundity of the ibis. By combining detailed rearing history in captivity with long-term post-release monitoring, we demonstrate that the initiation of parental rearing before the chicks' eyes open is the critical factor leading to increased pseudocopulation frequency and mating success in captive-born male ibis. Based on these results, not hand-rearing the chicks beyond the day after hatching would reduce the impact of hand-rearing on reproduction after release. Rearing methods that take into account the nestling period should be implemented to enhance the efficiency and reduce the cost of avian reintroduction projects.
Population Genetic Structure of Little Tern (Sternula albifrons) in Japan Inferred from Nucleotide Sequence Diversities of the Mitochondrial DNA Control Region

Abstract Little Tern Sternula albifrons sinensis was been categorized as Endangered Class II by the 2020 Ministry of the Environment's Red List in Japan. For an effective conservation program for the taxon, the unit of conservation needs to be understood. In this study, we investigated genetic and morphological diversity as a clue to clarify the units to be protected. Blood samples were collected from 47 individuals in four different breeding sites in Japan (Tokyo, Chiba, Fukuoka, Okinawa). The nucleotide sequences of the control region of mitochondrial DNA were used to analyze their genetic diversity and structure. Basic morphological features were also compared. Nucleic acid base substitution, deletion, or insertion were identified at 30 sites of the 1029-bp sequence alignment of the control region, leading to identification of 30 different haplotypes. Genetic diversity was high in the four breeding populations, and haplotype frequencies showed no indication that specific genotypes were present at extreme frequencies. This suggests that the population of Little Tern nesting in Japan has been maintained without recent bottleneck events. The haplotype network formed two major haplotype groups from the 30 haplotypes. Haplotypes of one group were abundant in the Tokyo, Chiba, and Fukuoka populations. In contrast, those of the other group were frequent in the Okinawa population. Pairwise haplotype analysis between populations also revealed that the genetic variations at Okinawa differ from those of the remaining three populations. Furthermore, the Okinawa population showed different morphological characteristics compared to the Tokyo/Chiba populations. These results collectively suggest that the population of Little Terns in Japan is divided into at least two different populations.
Boundary effects on entropy and two-site entanglement of the spin-1 valence-bond solid

We investigate the von Neumann entropy of a block of subsystem for the valence-bond solid (VBS) state with general open boundary conditions. We show that the effect of the boundary on the von Neumann entropy decays exponentially fast in the distance between the subsystem considered and the boundary sites. Further, we show that as the size of the subsystem increases, its von Neumann entropy exponentially approaches the summation of the von Neumann entropies of the two ends, the exponent being related to the size. In contrast to critical systems, where boundary effects to the von Neumann entropy decay slowly, the boundary effects in a VBS, a noncritical system, decay very quickly. We also study the entanglement between two spins. Curiously, while the boundary operators decrease the von Neumann entropy of L spins, they increase the entanglement between two spins.
Single‐pass stratified importance resampling

Resampling is the process of selecting from a set of candidate samples to achieve a distribution (approximately) proportional to a desired target. Recent work has revisited its application to Monte Carlo integration, yielding powerful and practical importance sampling methods. One drawback of existing resampling methods is that they cannot generate stratified samples. We propose two complementary techniques to achieve efficient stratified resampling. We first introduce bidirectional CDF sampling which yields the same result as conventional inverse CDF sampling but in a single pass over the candidates, without needing to store them, similarly to reservoir sampling. We then order the candidates along a space‐filling curve to ensure that stratified CDF sampling of candidate indices yields stratified samples in the integration domain. We showcase our method on various resampling‐based rendering problems.
A Microfacet‐based Hair Scattering Model

The development of scattering models and rendering algorithms for human hair remains an important area of research in computer graphics. Virtually all available models for scattering off hair or fur fibers are based on separable lobes, which bring practical advantages in importance sampling, but do not represent physically‐plausible microgeometry. In this paper, we contribute the first microfacet‐based hair scattering model. Based on a rough cylinder geometry with tilted cuticle scales, our far‐field model is non‐separable by nature, yet allows accurate importance sampling. Additional benefits include support for elliptical hair cross‐sections and an analytical solution for the reflected lobe using the GGX distribution. We show that our model captures glint‐like forward scattering features in the R lobe that have been observed before but not properly explained.
Smartphones and psychosocial development: Self-compassion mediates the association between trait anxiety and smartphone attachment in digital natives but not digital immigrants

ABSTRACT Cyberpsychological research suggests that interaction with and use of smartphones influences personal wellbeing and psychosocial development. Studies indicate that (a) the ways in which individuals manage their attachment to devices influences personal development, (b) greater smartphone attachment is associated with higher anxiety levels, and (c) personality differences might mediate this association. We investigated whether self-compassion (i.e. being kind and non-judgmental to oneself) might be such a mediating factor, and whether this mediational relationship differed between digital natives (n = 104, 18–25 years) and digital immigrants (n = 117, 30–60 years). Participants completed standardised scales measuring trait anxiety, self-compassion, and smartphone attachment/use. The mediational hypothesis was confirmed for digital natives only, suggesting that among these participants (who reported significantly higher anxiety levels) higher levels of self-compassion can provide a healthy buffer between psychological distress and unhealthy smartphone attachment. We conclude that programmatic self-compassion interventions could buffer negative developmental consequences of unhealthy smartphone attachment.
Measurement and physical model prediction on splash fluxes in a pilot TSL bath smelting furnace

Top Submerged Lance (TSL) furnaces used for non-ferrous smelting have high heat and mass transfer rates due to the intensive stirring and splashing generated by the lance. While splashing can cause accretion build-up in the upper cooler regions of the furnace, it plays an important role in heat and mass transfer and needs to be controlled to minimise accretion formations while maximising furnace productivity. In this work, splashing was studied by measuring the splash flux from a molten slag bath in a 300 kg pilot-scale TSL furnace and also from an ambient temperature aqueous-glycerol solution bath in a physical model. In both systems, total injection gas flowrate, lance immersion depth and splash height were examined to determine their effects on the splash flux. An empirical correlation was developed based on the results of the aqueous-glycerol physical model using the methodology of dimensional analysis. This correlation was then used to predict the splash for high temperature smelting conditions. Comparison of the predictions with both hot and cold experimental measurements showed the same variation trends and the predicted values were within an acceptable range, particularly in splash heights within 1 m above the bath surface and at medium to high gas flowrates with lance immersion depths being 1/6–1/3 of the bath height. It is concluded that the correlation can be potentially applied to predict splashing behaviour in TSL furnaces.
Making Decisions at Data Plane Speeds

Feedback control loops to implement self-driving networks constitute data collection to sense the network, and control algorithms to make decisions driving the network. Highquality data is necessary for smart decisions. Yet, highquality data is hard to obtain from the network data plane, due to insufficient visibility and large data volumes stemming from high packet rates. This paper distills principles to collect high-quality data arising from our own research experience: (i) filter and aggregate data as close to the source as possible; (ii) identify broad families of statistics that are measurable with bounded inaccuracy; (iii) don't assume lowlevel data plane software is easy to instrument, but instead (iv) apportion software flexibility by the time scales of the computation; and (v) prefer in-band approaches where possible for timely and efficient reactivity. We call the community to act upon these principles to leverage emerging opportunities using safely-extensible network stacks.
Stochastic residential occupancy schedules based on the American Time-Use Survey

The energy performance of residential buildings is closely correlated with occupants’ behavior and their schedules. Moreover, the energy consumption of heating, ventilation, and air conditioning (HVAC) systems, which are by far the biggest contributor to energy consumption in residential buildings, is controlled by the presence or absence of occupants in a building. Thus, accurate occupancy presence and activity profiles are important to determine actual energy demands and corresponding control schedules for residential buildings. Conventionally, building energy simulation tools typically use a single generic and static occupancy profile to represent a building’s occupancy schedule, regardless of day type or household size. However, literature in the field suggests that there is significant potential for improvement to allow for more flexibility and accuracy in the calculation of occupancy. The objective of this study is thus to develop a stochastic building occupancy model and propose it as a realistic replacement for the conventional generic static schedules. This three-state stochastic occupancy model is based on the 2019 American Time-Use Survey (ATUS) and considers the differences among weekdays, Saturdays, and Sundays. In this model, survey respondents are clustered based on the number of residents in their household and a first-order inhomogeneous Markov chain technique is used to generate occupancy presence schedules. The models’ results are then validated against the original ATUS data in terms of state probabilities, state durations, and number of state changes throughout the course of a day.
Research Status and Application of Magnesium Ion Battery Electrode Materials

Abstract Compared with lithium-ion batteries, magnesium ion batteries can theoretically provide more electrons, have a larger theoretical specific capacity, and are abundant in magnesium compared to increasingly scarce lithium resources, which can effectively reduce the production cost of batteries. Therefore, the research of cathode material for magnesium ion battery has important scientific significance and practical value. However, there are still some problems hindering the commercial development of magnesium ion batteries. Due to the high charge density, strong polarization effect and slow diffusion kinetics of Mg2+, it is still a great challenge to develop positive electrode materials that meet current commercial requirements. This paper mainly reviews the development status and future development trend of magnesium ion battery in recent years, as well as the working principle and characteristics of magnesium ion battery, and puts forward the related application of magnesium ion material in anode and cathode of battery. Compared with lithium ion battery, magnesium ion material has obvious performance advantages, which is an important topic for the development of electrode material in the future.
Analyzing and visualizing Twitter conversations

Social media platforms are public venues where conversations about issues of public interest take place. Much recent research has been devoted to evaluating the degree to which online conversations capture public opinion on issues of broad societal interest. We describe a robust and scalable platform to support such studies. Our platform allows the analysis of three semantic aspects of tweets, namely the personal values, sentiment, and humor expressed in them, as well as the public’s engagement with them. I n addition, it aggregates these indicators at the level of tweet authors to shed light on the activities and style of influencers of public opinion. Finally, it offers rich visualizations to enable users to gain insights on their datasets. We demonstrate the usefulness of our platform with two case studies: (a) analyzing the fragmented narratives around established (hydro, oil and gas, coal, nuclear) and new (solar, wind, geothermal, biomass) energy sources; and (b) comparing the social-media brands of academic institutions.
Shedding Light on the Blockchain Disintermediation Mystery: A Review and Future Research Agenda

Blockchain technology has been in the interest of IS researchers and practitioners for several years. One key reason for this curiosity is the possibility to carry out peer-to-peer transactions without a trusted intermediary. Building upon this capability, many researchers posited that blockchain technology would remove traditional intermediaries from their market position. This process has been described in electronic markets literature as Disintermediation. However, other researchers proposed a more distinct perspective by proposing that blockchain technology will not facilitate Disintermediation in all settings. Thus, no unified view on this topic exists yet. Our literature review identifies three dominating concepts in blockchain literature: Extensive Disintermediation, Limited Disintermediation, and Re-Intermediation. We further highlight in our findings that most of the identified literature does not consider all market functions as described in the electronic markets literature. Hence, we provide a structured overview of the field and possibilities for future research.