Hasil untuk "Earthwork. Foundations"

K. Nguyen

C. Mancini, G. Tino, S. Capozziello

The so-called Geometric Trinity of Gravity includes General Relativity (GR), based on spacetime curvature; the Teleparallel Equivalent of GR (TEGR), which relies on spacetime torsion; and the Symmetric Teleparallel Equivalent of GR (STEGR), grounded in nonmetricity. Recent studies demonstrate that GR, TEGR, and STEGR are dynamically equivalent, raising questions about the fundamental structure of spacetime, the under-determination of these theories, and whether empirical distinctions among them are possible. The aim of this work is to show that they are equivalent in many features but not exactly in everything. In particular, their relationship with the Equivalence Principle (EP) is different. The EP is a deeply theory-laden assumption, which is assumed as fundamental in constructing GR, with significant implications for our understanding of spacetime. However, it introduces unresolved conceptual issues, including its impact on the nature of the metric and connection, its meaning at the quantum level, tensions with other fundamental interactions and new physics, and its role in dark matter and dark energy problems. In contrast, TEGR and STEGR recover the EP, in particular in its strong formulation, but do not rely on it as a foundational principle. The fact that GR, TEGR, and STEGR are equivalent in non-trivial predictions, but the EP is not necessary for TEGR and STEGR, suggests that it may not be a fundamental feature but an emergent one, potentially marking differences in the empirical content of the three theories. Thus, the developments within the Geometric Trinity framework challenge traditional assumptions about spacetime and may help to better understand some of the unresolved foundational difficulties related to the EP.

Maria Gkevrou, Dimitrios Stamovlasis

Chukwuemeka Kingsley John, Jaan H. Pu

The demand for innovative, sustainable foundation engineering solutions has increased due to the rising pressure to lessen the environmental impact of major developments. The integration of geosynthetics and recycled materials into intelligent foundation design is critically examined in this work as a means of achieving robust, low-carbon, and resource-efficient infrastructure systems. This paper's thematic analysis and structured literature review demonstrate how waste-derived materials, including fly ash, recycled concrete aggregates, waste plastics, and industrial by-products, can successfully replace conventional building materials in ground improvement and foundation applications. Furthermore, geosynthetics—such as geotextiles and geogrids—provide lightweight, long-lasting, and eco-friendly reinforcement substitutes that improve soil performance while using less material. The study also looks at how real-time monitoring, sensor technologies, and artificial intelligence (AI) might improve structural performance, maximise material selection, and prolong the life of foundation systems. The results of life cycle assessment (LCA) and life cycle cost analysis (LCCA) show significant economic and environmental advantages, such as lower energy use, greenhouse gas emissions, and overall project costs. However, the main obstacles to broad adoption are found to be issues like material heterogeneity, a lack of standardisation, and a limited degree of digital integration. To promote sustainable foundation practices through material innovation, digital transformation, and the concepts of the circular economy, the study ends by offering practical suggestions for researchers, industry practitioners, and legislators. The results provide insightful information on how smart, sustainable foundation design may support the global shift to more resilient and environmentally friendly built environments.

Max Chen, Edward Morrell

One of the more exploratory and experimental forms of output in the games research community involves authors utilising games they have developed in the academic context. Whether fully embodying the role of a designer-researcher in communicating the development process, or presenting the data that derives from a complete game artefact, academics can use games as an integral part of their research. The academic game making context is distinct from other forms of game creation, with academia allowing for certain freedoms while also enforcing its own strict constraints. Our understanding of academic games derives from how they have been reported in the literature, as there is limited preservation of these games as playable experiences. For the 20th Foundations of Digital Games (FDG) conference, we analysed its corpus of 1,437 articles to take examine their historical development and identify some of the developmental trends of academic games as reported over nearly two decades. Through this study, we identify the diverse purposes of these games and examine how they have contributed to advancing research efforts.

Audrey Burzawa, Ludovic Bodet, Marine Dangeard et al.

Assessing Railway Earthworks (RE) requires non-destructive and time-efficient diagnostic tools. This study evaluates the relevance of shear-wave velocity ($V_s$) profiling using Multichannel Analysis of Surface Waves (MASW) for detecting Low Velocity Layers (LVLs) in disturbed RE zones. To enhance time-efficiency, a towed seismic setup (Landstreamer) was compared with a conventional one. Once qualified, the Landstreamer was deployed on the ballast for roll-along acquisition, showing greatly improved efficiency and good imaging capability. A probabilistic framework adopted in this study additionally enhances quantification of uncertainties and helps in interpretation of $V_s$ models, facilitating reliable decision-making in infrastructure management.

Natsuki Ueno, Shoichi Koyama

The spatial information of sound plays a crucial role in various situations, ranging from daily activities to advanced engineering technologies. To fully utilize its potential, numerous research studies on spatial audio signal processing have been carried out in the literature. Sound field estimation is one of the key foundational technologies that can be applied to a wide range of acoustic signal processing techniques, including sound field reproduction using loudspeakers and binaural playback through headphones. The purpose of this paper is to present an overview of sound field estimation methods. After providing the necessary mathematical background, two different approaches to sound field estimation will be explained. This paper focuses on clarifying the essential theories of each approach, while also referencing state-of-the-art developments. Finally, several acoustic signal processing technologies will be discussed as examples of the application of sound field estimation.

R. A. Stillwell, A. Karboski, M. Hayman et al.

<p>A method for expanding the observational capabilities of diode-laser-based atmospheric lidar is discussed. A straightforward test, consisting of interleaved “Long” and “Short” laser pulses, is developed to demonstrate how shot-to-shot modification of laser pulse characteristics can enhance the performance of low-power, diode-laser-based lidar and could benefit atmospheric observations. Two examples are given to demonstrate the technique. In the first, water vapor profiling is extended closer to the surface while simultaneously maintaining sufficient far-range performance. These results are verified with collocated measurements. In the second example, clouds are resolved at high vertical spatial resolution with a high signal-to-noise ratio. Details of the lidar instrument hardware and the method to combine the laser pulses of different durations are given.</p>

A. R. Groos, A. R. Groos, N. Brand et al.

<p>Glaciers are an integral part of the high mountain environment and interact with the overlying atmosphere and surrounding terrain in a complex and dynamic manner. The energy exchange between the glacier surface and the overlying atmosphere controls ice melt rates and promotes a characteristic microclimate, including the formation of a low-level katabatic jet that interacts with other, often thermally driven winds in alpine terrain. Information on the local circulation and structure of the atmospheric boundary layer over glaciers is crucial for studying cryosphere-atmosphere interactions and for investigating the characteristics of the katabatic wind, its broader cooling effect, and its susceptibility to be disrupted by strong valley or synoptic winds that promote heat advection from the ice- and snow-free periphery towards the glacier. While the number of ground-based measurements from weather stations and meteorological towers installed on glaciers for boundary layer research has increased in recent years, a lightweight and mobile measurement technique for atmospheric sounding over alpine glaciers has not yet been available. Here we describe a new measurement technique based on a low-cost and open-source fixed-wing UAV, which allows sounding the atmospheric boundary layer over glaciers up to several hundred metres above the surface. In the frame of a feasibility study in 2021, two half-day (16 June, 23 September) and two 24 h campaigns (9/10 July, 25/26 August), including nocturnal soundings, were performed, demonstrating the UAV's capability to reach heights of up to 800 m above the glacier surface. From these campaigns, 40 profiles of air temperature, specific humidity, wind speed, wind direction, and turbulence were derived. The results highlight characteristic features of the glacier boundary layer, including a persistent surface-based inversion, a cool and dry katabatic wind confined to the lowest 50 m a.g.l., an overlying shear layer, and a warmer, often more humid valley wind above 100–200 m a.g.l. These observations illustrate how the boundary layer responds to synoptic forcing and local winds and demonstrate the potential of UAV-based atmospheric soundings for advancing glacier meteorology in complex alpine terrain.</p>

Vasyl Mitinsky, Tatiana Sushytska, Y. Vynnykov et al.

Positive experience of arranging high-rise buildings with underground parking lots in soil conditions that have a layer of limestone in the zone of their interaction with pile foundations is presented. It was found that the engineering and geological conditions of Odesa should be classified as complex, in particular due to the presence of weak loess soils in the upper part of the section, and limestone layers in its lower part. In the middle part of the section there is a layer consisting of heavy loams and clays. More compressible sandy loams and meiotic clays serve as the base of the limestones. The insignificant thickness of the middle layer makes it necessary to transfer the load from the buildings with piles to the limestone. With their insignificant thickness, the presence of cracks and outcrops, it becomes possible to develop an excessive tilt of the building as a result of uneven (one-sided) pressing of limestone, which has the nature of a cemented rock. It has been proven that to create a reliable pile foundation, it is important not only to hydraulically tamponade the excavations, but also to consolidate the massif in the area of ​​their location by high-pressure injection of soil-cement solution using cuff columns, as well as to correctly assess the mechanical characteristics of limestone and, first of all, its strength parameters. The conditions for the construction of buildings with a high number of floors on prismatic piles are substantiated. The results of monitoring their subsidence during construction and operation are presented. The experience of 3D modeling by the method of finite elements (FEM) of joint work of the pile-slab foundation of buildings with a base containing layers of limestone and layers of more compressible clay soils in the zone of underground workings is presented.

A. Morgun, I. Met, Dmitry Zapisov et al.

The topic of predicting the bearing capacity of foundation structures is relevant for the entire construction industry, which plays the most important role in all branches of the country. The aim of the work is to improve the mathematical apparatus of the numerical method of boundary elements in applied studies of the behavior under load of reinforced foundations. Soil mechanics serves as a theoretical basis for calculations when choosing the type and size of the foundation of a building, as well as when designing soil structures. Therefore, the level of development of soil mechanics significantly affects the efficiency and reliability of the decisions made. Design engineers, when it is necessary to take into account the interaction of a structure with the soil, face great uncertainty and empirical evidence. Since soils are dispersed formations, they are characterized by significant structural heterogeneity and a significant dependence of their characteristics on the level of external influences; they are a natural substance. As a method of analyzing the problem, a modern numerical MGE was used, which allows to sharply increase the level of adequacy of the design solution, to improve the calculation scheme. The practical value of the conducted research should include a reliable picture of the “load-settlement” graph obtained by MGE for disperse soils of a construction site for analyzing the forecast of the safe limit state of a building on reinforced foundations. The current state of development of soil mechanics is characterized by an active transition to new calculation models that more fully reflect the real disperse properties of soils. Experience in designing foundation structures using numerical MGE is useful for engineers, students, and graduate students in construction specialties working in the field of soil mechanics and its practical applications.

Maik Reddiger

By formulating the axioms of quantum mechanics, von Neumann also laid the foundations of a "quantum probability theory". As such, it is regarded a generalization of the "classical probability theory" due to Kolmogorov. Outside of quantum physics, however, Kolmogorov's axioms enjoy universal applicability. This raises the question of whether quantum physics indeed requires such a generalization of our conception of probability or if von Neumann's axiomatization of quantum mechanics was contingent on the absence of a general theory of probability in the 1920s. This work argues in favor of the latter position. In particular, it shows how to construct a mathematically rigorous theory for non-relativistic $N$-body quantum systems subject to a time-independent scalar potential, which is based on Kolmogorov's axioms and physically natural random variables. Though this theory is provably distinct from its quantum mechanical analog, it nonetheless reproduces central predictions of the latter. Further work may make an empirical comparison possible. Moreover, the approach can in principle be adapted to other classes of quantum-mechanical models. Part II of this series discusses the empirical violation of Bell inequalities in the context of this approach. Part III addresses the projection postulate and the question of measurement.

Xiao Xiang Zhu, Zhitong Xiong, Yi Wang et al.

Foundation models have enormous potential in advancing Earth and climate sciences, however, current approaches may not be optimal as they focus on a few basic features of a desirable Earth and climate foundation model. Crafting the ideal Earth foundation model, we define eleven features which would allow such a foundation model to be beneficial for any geoscientific downstream application in an environmental- and human-centric manner.We further shed light on the way forward to achieve the ideal model and to evaluate Earth foundation models. What comes after foundation models? Energy efficient adaptation, adversarial defenses, and interpretability are among the emerging directions.

James Demmel, Ioana Dumitriu, Ryan Schneider

We present a randomized, inverse-free algorithm for producing an approximate diagonalization of any $n \times n$ matrix pencil $(A,B)$. The bulk of the algorithm rests on a randomized divide-and-conquer eigensolver for the generalized eigenvalue problem originally proposed by Ballard, Demmel, and Dumitriu [Technical Report 2010]. We demonstrate that this divide-and-conquer approach can be formulated to succeed with high probability provided the input pencil is sufficiently well-behaved, which is accomplished by generalizing the recent pseudospectral shattering work of Banks, Garza-Vargas, Kulkarni, and Srivastava [Foundations of Computational Mathematics 2022]. In particular, we show that perturbing and scaling $(A,B)$ regularizes its pseudospectra, allowing divide-and-conquer to run over a simple random grid and in turn producing an accurate diagonalization of $(A,B)$ in the backward error sense. The main result of the paper states the existence of a randomized algorithm that with high probability (and in exact arithmetic) produces invertible $S,T$ and diagonal $D$ such that $||A - SDT^{-1}||_2 \leq \varepsilon$ and $||B - ST^{-1}||_2 \leq \varepsilon$ in at most $O \left(\log^2 \left( \frac{n}{\varepsilon} \right) T_{\text{MM}}(n) \right)$ operations, where $T_{\text{MM}}(n)$ is the asymptotic complexity of matrix multiplication. This not only provides a new set of guarantees for highly parallel generalized eigenvalue solvers but also establishes nearly matrix multiplication time as an upper bound on the complexity of inverse-free, exact arithmetic matrix pencil diagonalization.

Xuan Zhang, Limei Wang, Jacob Helwig et al.

Advances in artificial intelligence (AI) are fueling a new paradigm of discoveries in natural sciences. Today, AI has started to advance natural sciences by improving, accelerating, and enabling our understanding of natural phenomena at a wide range of spatial and temporal scales, giving rise to a new area of research known as AI for science (AI4Science). Being an emerging research paradigm, AI4Science is unique in that it is an enormous and highly interdisciplinary area. Thus, a unified and technical treatment of this field is needed yet challenging. This work aims to provide a technically thorough account of a subarea of AI4Science; namely, AI for quantum, atomistic, and continuum systems. These areas aim at understanding the physical world from the subatomic (wavefunctions and electron density), atomic (molecules, proteins, materials, and interactions), to macro (fluids, climate, and subsurface) scales and form an important subarea of AI4Science. A unique advantage of focusing on these areas is that they largely share a common set of challenges, thereby allowing a unified and foundational treatment. A key common challenge is how to capture physics first principles, especially symmetries, in natural systems by deep learning methods. We provide an in-depth yet intuitive account of techniques to achieve equivariance to symmetry transformations. We also discuss other common technical challenges, including explainability, out-of-distribution generalization, knowledge transfer with foundation and large language models, and uncertainty quantification. To facilitate learning and education, we provide categorized lists of resources that we found to be useful. We strive to be thorough and unified and hope this initial effort may trigger more community interests and efforts to further advance AI4Science.

Andrei Rodin

The received Hilbert-style axiomatic foundations of mathematics has been designed by Hilbert and his followers as a tool for meta-theoretical research. Foundations of mathematics of this type fail to satisfactory perform more basic and more practically-oriented functions of theoretical foundations such as verification of mathematical constructions and proofs. Using alternative foundations of mathematics such as the Univalent Foundations is compatible with using the received set-theoretic foundations for meta-mathematical purposes provided the two foundations are mutually interpretable. Changes in foundations of mathematics do not, generally, disqualify mathematical theories based on older foundations but allow for reconstruction of these theories on new foundations. Mathematics is one but its foundations are many.

Ohkyung Kwon

There is much recent development towards interferometric measurements of holographic quantum uncertainties in an emergent background space-time. Despite increasing promise for the target detection regime of Planckian strain power spectral density, the foundational insights of the motivating theories have not been connected to a phenomenological model of observables measured in a realistic experiment. This work proposes a candidate model, based on the central hypothesis that all horizons are universal boundaries of coherent quantum information -- where the decoherence of space-time happens for the observer. The prediction is inspired by 't Hooft's algebra for black hole information that gives coherent states on horizons, whose spatial correlations were shown by Verlinde and Zurek to also appear on holographic fluctuations of causal boundaries in flat space-time (conformal Killing horizons). Time-domain correlations are projected from Planckian jitters whose coherence scales match causal diamonds, motivated by Banks' framework for the emergence of space-time and locality. The universality of this coherence on causal horizons compels a multimodal research program probing concordant signatures: An analysis of cosmological data to probe primordial correlations, motivated by Hogan's interpretation of well-known CMB anomalies as coherent fluctuations on the inflationary horizon, and upcoming 3D interferometers to probe causal diamonds in flat space-time. Candidate interferometer geometries are presented, with a modeled frequency spectrum for each design.

P. Marquet, P. Martinet, J.-F. Mahfouf et al.

<p>This study aims at introducing two conservative thermodynamic variables (moist-air entropy potential temperature and total water content) into a one-dimensional variational data assimilation system (1D-Var) to demonstrate their benefits for use in future operational assimilation schemes. This system is assessed using microwave brightness temperatures (TBs) from a ground-based radiometer installed during the SOFOG3D field campaign, dedicated to fog forecast improvement.</p> <p>An underlying objective is to ease the specification of background error covariance matrices that are highly dependent on weather conditions when using classical variables, making difficult the optimal retrievals of cloud and thermodynamic properties during fog conditions. Background error covariance matrices for these new conservative variables have thus been computed by an ensemble approach based on the French convective scale model AROME, for both all-weather and fog conditions. A first result shows that the use of these matrices for the new variables reduces some dependencies on the meteorological conditions (diurnal cycle, presence or not of clouds) compared to typical variables (temperature, specific humidity).</p> <p>Then, two 1D-Var experiments (classical vs. conservative variables) are evaluated over a full diurnal cycle characterized by a stratus-evolving radiative fog situation, using hourly TB.</p> <p>Results show, as expected, that TBs analysed by the 1D-Var are much closer to the observed ones than the background values for both variable choices. This is especially the case for channels sensitive to water vapour and liquid water. On the other hand, analysis increments in model space (water vapour, liquid water) show significant differences between the two sets of variables.</p>

D. A. Newnham, M. A. Clilverd, W. D. J. Clark et al.

<p>Ground-based observations of 11.072 <span class="inline-formula">GHz</span> atmospheric ozone (<span class="inline-formula">O₃</span>) emission have been made using the Ny-Ålesund Ozone in the Mesosphere Instrument (NAOMI) at the UK Arctic Research Station (latitude 78<span class="inline-formula">^∘</span>55<span class="inline-formula">^′</span>0<span class="inline-formula">^′′</span> N, longitude 11<span class="inline-formula">^∘</span>55<span class="inline-formula">^′</span>59<span class="inline-formula">^′′</span> E), Spitsbergen. Seasonally averaged <span class="inline-formula">O₃</span> vertical profiles in the Arctic polar mesosphere–lower thermosphere region for night-time and twilight conditions in the period 15 August 2017 to 15 March 2020 have been retrieved over the altitude range 62–98 <span class="inline-formula">km</span>. NAOMI measurements are compared with corresponding, overlapping observations by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite instrument. The NAOMI and SABER version 2.0 data are binned according to the SABER instrument 60 <span class="inline-formula">d</span> yaw cycles into nominal 3-month “winter” (15 December–15 March), “autumn” (15 August–15 November), and “summer” (15 April–15 July) periods. The NAOMI observations show the same year-to-year and seasonal variabilities as the SABER 9.6 <span class="inline-formula">µm</span> <span class="inline-formula">O₃</span> data. The winter night-time (solar zenith angle, SZA <span class="inline-formula">≥</span> 110<span class="inline-formula">^∘</span>) and twilight (75<span class="inline-formula">^∘</span> <span class="inline-formula">≤</span> SZA <span class="inline-formula">≤</span> 110<span class="inline-formula">^∘</span>) NAOMI and SABER 9.6 <span class="inline-formula">µm</span> <span class="inline-formula">O₃</span> volume mixing ratio (VMR) profiles agree to within the measurement uncertainties. However, for autumn twilight conditions the SABER 9.6 <span class="inline-formula">µm</span> <span class="inline-formula">O₃</span> secondary maximum VMR values are higher than NAOMI over altitudes 88–97 <span class="inline-formula">km</span> by 47 % and 59 %, respectively in 2017 and 2018. Comparing the two SABER channels which measure <span class="inline-formula">O₃</span> at different wavelengths and use different processing schemes, the 9.6 <span class="inline-formula">µm</span> <span class="inline-formula">O₃</span> autumn twilight VMR data for the three years 2017–2019 are higher than the corresponding 1.27 <span class="inline-formula">µm</span> measurements with the largest difference (58 %) in the 65–95 <span class="inline-formula">km</span> altitude range similar to the NAOMI observation. The SABER 9.6 <span class="inline-formula">µm</span> <span class="inline-formula">O₃</span> summer daytime (SZA <span class="inline-formula">&lt;</span> 75<span class="inline-formula">^∘</span>) mesospheric <span class="inline-formula">O₃</span> VMR is also consistently higher than the 1.27 <span class="inline-formula">µm</span> measurement, confirming previously reported differences between the SABER 9.6 <span class="inline-formula">µm</span> channel and measurements of mesospheric <span class="inline-formula">O₃</span> by other satellite instruments.</p>

Narayani Tyagi, Ken Wharton

Although the path-integral formalism is known to be equivalent to conventional quantum mechanics, it is not generally obvious how to implement path-based calculations for multi-qubit entangled states. Whether one takes the formal view of entangled states as entities in a high-dimensional Hilbert space, or the intuitive view of these states as a connection between distant spatial configurations, it may not even be obvious that a path-based calculation can be achieved using only paths in ordinary space and time. Previous work has shown how to do this for certain special states; this paper extends those results to all pure two-qubit states, where each qubit can be measured in an arbitrary basis. Certain three-qubit states are also developed, and path integrals again reproduce the usual correlations. These results should allow for a substantial amount of conventional quantum analysis to be translated over into a path-integral perspective, simplifying certain calculations, and more generally informing research in quantum foundations.