Dmitry Eremeev, Gleb Bazhenov, Oleg Platonov
et al.
While foundation models have revolutionized such fields as natural language processing and computer vision, their potential in graph machine learning remains largely unexplored. One of the key challenges in designing graph foundation models (GFMs) is handling diverse node features that can vary across different graph datasets. While many works on GFMs have focused exclusively on text-attributed graphs, the problem of handling arbitrary features of other types in GFMs has not been fully addressed. However, this problem is not unique to the graph domain, as it also arises in the field of machine learning for tabular data. In this work, motivated by the recent success of tabular foundation models (TFMs) like TabPFNv2 or LimiX, we propose G2T-FM, a simple framework for turning tabular foundation models into graph foundation models. Specifically, G2T-FM augments the original node features with neighborhood feature aggregation, adds structural embeddings, and then applies a TFM to the constructed node representations. Even in a fully in-context regime, our model achieves strong results, significantly outperforming publicly available GFMs and performing competitively with, and often better than, well-tuned GNNs trained from scratch. Moreover, after finetuning, G2T-FM surpasses well-tuned GNN baselines. In particular, when combined with LimiX, G2T-FM often outperforms the best GNN by a significant margin. In summary, our paper reveals the potential of a previously overlooked direction of utilizing tabular foundation models for graph machine learning tasks.
Pietro Barbiero, Mateo Espinosa Zarlenga, Alberto Termine
et al.
We argue that existing definitions of interpretability are not actionable in that they fail to inform users about general, sound, and robust interpretable model design. This makes current interpretability research fundamentally ill-posed. To address this issue, we propose a definition of interpretability that is general, simple, and subsumes existing informal notions within the interpretable AI community. We show that our definition is actionable, as it directly reveals the foundational properties, underlying assumptions, principles, data structures, and architectural features necessary for designing interpretable models. Building on this, we propose a general blueprint for designing interpretable models and introduce the first open-sourced library with native support for interpretable data structures and processes.
Quantum algorithms for classical physics problems expose new patterns of quantum information flow as compared to the many-body Schrödinger equation. As a result, besides their potential practical applications, they also offer a valuable theoretical and computational framework to elucidate the foundations of quantum mechanics, particularly the validity of the many-body Schrödinger equation in the limit of large number of particles, on the order of the Avogadro number. This idea is illustrated by means of a concrete example, the Block-Encoded Carleman embedding of the Lattice Boltzmann formulation of fluid dynamics (CLB).
Federated Foundation Models (FedFMs) represent a distributed learning paradigm that fuses general competences of foundation models as well as privacy-preserving capabilities of federated learning. This combination allows the large foundation models and the small local domain models at the remote clients to learn from each other in a teacher-student learning setting. This paper provides a comprehensive summary of the ten challenging problems inherent in FedFMs, encompassing foundational theory, utilization of private data, continual learning, unlearning, Non-IID and graph data, bidirectional knowledge transfer, incentive mechanism design, game mechanism design, model watermarking, and efficiency. The ten challenging problems manifest in five pivotal aspects: ``Foundational Theory," which aims to establish a coherent and unifying theoretical framework for FedFMs. ``Data," addressing the difficulties in leveraging domain-specific knowledge from private data while maintaining privacy; ``Heterogeneity," examining variations in data, model, and computational resources across clients; ``Security and Privacy," focusing on defenses against malicious attacks and model theft; and ``Efficiency," highlighting the need for improvements in training, communication, and parameter efficiency. For each problem, we offer a clear mathematical definition on the objective function, analyze existing methods, and discuss the key challenges and potential solutions. This in-depth exploration aims to advance the theoretical foundations of FedFMs, guide practical implementations, and inspire future research to overcome these obstacles, thereby enabling the robust, efficient, and privacy-preserving FedFMs in various real-world applications.
<p>The Advanced Himawari Imager (AHI) onboard the Himawari-8 geostationary satellite is an imager with 16 spectral bands covering from the visible to infrared. The AHI has high temporal resolution with observation frequency of every 10 min and high spatial resolution 0.5–2 km (depending on channel) for full disk, which provides great potential for studying the dynamics of aerosol properties in East Asia and Western Pacific regions. In this study, the development of aerosol and surface property retrievals from the AHI/Himawari-8 using the Generalized Retrieval of Atmosphere and Surface Properties (GRASP) algorithm is described. Due to the pseudo multi-angular observations obtained from AHI/Himawari-8 and the flexibility of GRASP algorithm with its innovative multi-pixel concept, multiple time and spatial pixels were retrieved simultaneously with both aerosol and surface properties constrained between the pixels together with additional constraints on spectral variability of underlying surface parameters within each pixel.</p>
<p>The developed GRASP based algorithm has been applied to AHI/Himwari-8 observations over land for the entire year of 2018, and over ocean for May 2018 only, due to computational resource limitations and the relatively lower complexity of aerosol retrievals over ocean. The generated retrieval products were validated against the Aerosol Robotic Network (AERONET) measurements and were also intercompared with the Moderate Resolution Imaging Spectroradiometer (MODIS) surface products. Overall, the validation analysis shows robust agreement of AHI/GRASP spectral AOD product with AERONET with correlation coefficients of 0.82–0.93 across the spectrum over land. The AHI/GRASP results demonstrate encouraging agreement with AERONET that is with 34.4 % of the AOD (510 nm) satisfying the Global Climate Observing System (GCOS) requirement, and a bias within <span class="inline-formula">±0.02</span> for AOD over land. The validation for fine and coarse mode AOD also showed promising results with a correlation of 0.89 and mean bias of 0.04 for fine mode AOD when compared with AERONET measurements. As for the intercomparisons with MODIS products, the overall performance is quite comparable to MODIS surface products. In addition to the analysis of AHI/Himawari-8 alone retrieval, this study demonstrated a novel synergetic retrieval between AHI/Himawari-8 and micro-pulse lidar (MPL). Using this synergy resulted in further improvements of the aerosol retrievals especially over the low AOD conditions due to the improved sensitivity to aerosol.</p>
В роботі розглянуто питання вдосконалення роботизованої платформи Niryo One шляхом оптимізації режимів роботи приводу маніпуля-тора. Актуальність дослідження зумовлена необхідністю підвищення ефективності та точності роботи робототехнічних систем у промислових і дослідницьких застосуваннях. У другій частині дослідження представлено розробку математичної моделі динаміки маніпулятора, яка враховує особливості конструкції та параметри платформи Niryo One. На основі побудованої моделі проведено оптимізацію траєкторій руху маніпулятора з використанням методу послідовного квадратичного програмування (SLSQP – Sequential Least Squares Programming). Оптимізація спрямована на міні-мізацію енергоспоживання та часу виконання завдань при дотриманні обмежень на динамічні характеристики системи.
Запропонований підхід до визначення оптимальних режимів руху базується на чисельних методах нелінійного програмування. В результаті оптимізації отримано траєкторії, що забез-печують зниження навантаження на приводи та підвищення плавності руху порівняно з типовими режимами, реалізованими в стандартному програмному забезпеченні платформи. Проведено порівняльний аналіз оптимальних і типових режимів руху за критеріями енергоефективності та динаміки роботи.
Отримані результати можуть бути використані для модернізації існуючих та розробки нових алгоритмів керування двомасовими робото-технічними системами, а також для підвищення надійності та ресурсу роботи. Перспективи подальших досліджень пов’язані з адаптацією розробленого методу для маніпуляторів з іншими кінематичними схемами та в умовах змінних зовнішніх навантажень.
This paper presents an enhanced adaptive random Fourier features (ARFF) training algorithm for shallow neural networks, building upon the work introduced in"Adaptive Random Fourier Features with Metropolis Sampling", Kammonen et al., \emph{Foundations of Data Science}, 2(3):309--332, 2020. This improved method uses a particle filter-type resampling technique to stabilize the training process and reduce the sensitivity to parameter choices. The Metropolis test can also be omitted when resampling is used, reducing the number of hyperparameters by one and reducing the computational cost per iteration compared to the ARFF method. We present comprehensive numerical experiments demonstrating the efficacy of the proposed algorithm in function regression tasks as a stand-alone method and as a pretraining step before gradient-based optimization, using the Adam optimizer. Furthermore, we apply the proposed algorithm to a simple image regression problem, illustrating its utility in sampling frequencies for the random Fourier features (RFF) layer of coordinate-based multilayer perceptrons. In this context, we use the proposed algorithm to sample the parameters of the RFF layer in an automated manner.
The basic data on the volume of formation and composition of fly ash, which is a product of coal combustion at thermal power stations, are given. The analysis of the current state of ways of managing fly ash makes it possible to distinguish the following main directions: physical-mechanical, physical-chemical, biological and combined methods of handling it, which are used in agriculture (use as fertilizers and pesticides; chemical land reclamation: regulation of the structure and pH of the soil); during earthworks (reinforcement of weak and expansive soils, use as tamponage compositions, arrangement of embankments and dams); road construction (strengthening of the soil for the lower layers of the road surface; production of asphalt, cement-concrete mixtures for arranging the foundations of road clothing, as well as crushed stone-sand and gravel-sand mixtures reinforced with cement); building materials industry (cement, concrete, building solutions, geopolymers, bricks, building blocks, glass, glass ceramics, building ceramics, porous ceramics, rolled waterproofing materials); in protective coatings (paints, enamels, enamel glass, shotcrete, heat-protective and heat-insulating coatings); as sorbents and catalysts and their carriers; in mechanical engineering (abrasive, frictional, filtering and lubricating materials, materials for soldering, foundry sand forms or rods); as other materials (pigments, polymer composites, elements of chemical sources of electric current, accumulators of certain substances, carbon nanoparticles (fullerenes, nanotubes), cosmetics and hygiene products); in pyrometallurgical and hydrometallurgical methods of recovery of chemical elements; in alloys and metal matrix composites; for extracting rare earth elements. Currently, the most appropriate methods of disposal of fly ash are either its direct use with a minimal change in its properties, or its use with minimal processing and minimization of the formation of new waste, in particular in the building materials industry and road construction. Bibl. 164, Fig. 3.
A. S. Arora, Kishor Bharti, Alexandru Cojocaru
et al.
Bell non-locality is a fundamental feature of quantum mechanics whereby measurements performed on “spatially separated” quantum systems can exhibit correlations that cannot be understood as revealing predetermined values. This is a special case of the more general phenomenon of “quantum contextuality”, which says that such correlations can occur even when the measurements are not necessarily on separate quantum systems, but are merely “compatible” (i.e. commuting). Crucially, while any non-local game yields an experiment that demonstrates quantum advantage by leveraging the “spatial separation” of two or more devices (and in fact several such demonstrations have been conducted successfully in recent years), the same is not true for quantum contextuality: finding the contextuality analogue of such an experiment is arguably one of the central open questions in the foundations of quantum mechanics. In this work, we show that an arbitrary contextuality game can be compiled into an “operational test of contextuality” involving a single quantum device, by only making the assumption that the device is computationally bounded. Our work is inspired by the recent work of Kalai et al. (STOC '23) that converts any non-local game into a classical test of quantum advantage with a single device. The central idea in their work is to use cryptography to enforce spatial separation within subsystems of a single quantum device. Our work can be seen as using cryptography to enforce “temporal separation”, i.e. to restrict communication between sequential measurements. Beyond contextuality, we employ our ideas to design a “proof of quantumness” that, to the best of our knowledge, is arguably even simpler than the ones proposed in the literature so far.
The theory of flows was used as a crucial tool in the recent proof by Margolis, Rhodes and Schilling that Krohn-Rhodes complexity is decidable. In this paper we begin a systematic study of aperiodic flows. We give the foundations of the theory of flows and give a unified approach to the Presentation Lemma and its relations to flows and the Slice Theorem. We completely describe semigroups having a flow over the trivial semigroup and connect this to classical results in inverse semigroup theory. We reinterpret Tilson's Theorem on the complexity of small monoids in terms of flows. We conclude with examples of semigroups built from the character table of Abelian Groups that have an aperiodic flows.
<p>This study describes a high-performance single-particle mass spectrometry (HP-SPAMS) design in detail. The comprehensive improvements in the injection system, optical sizing system, mass spectrometry, and data acquisition system have improved particle detection efficiency and chemical analysis. The combination of an aerodynamic particle concentrator (APC) system and a wide range of aerodynamic lenses (ADLs) enables the concentration of particles in the 100–5000 nm range. Using an APC increases the instrument inlet flow by a factor of 3–5. The ion delayed-exaction technology of bipolar time-of-flight mass spectrometry improves the mass resolution by 2–3 times, allowing the differentiation of isobaric ions of different substances. Moreover, the four-channel data acquisition technology greatly enhances the dynamic range of mass spectrometry. The improved HP-SPAMS enhances the overall capability of the instrument in terms of particle detection number and scattering efficiency. Moreover, it improves accuracy and sensitivity for component identification of individual particles.</p>
<p>The experimental performance of HP-SPAMS shows that the scattering efficiency of polystyrene latex microspheres is almost 70 %–100 % in the range of 300–3000 nm. Compared to the previous SPAMS, HP-SPAMS has a larger inlet flow rate and scattering efficiency and a higher laser frequency, which makes HP-SPAMS increase the effective number of particles detected and improve the temporal resolution of detection. For the analysis of individual particles, HP-SPAMS achieves an average mass spectral resolution of 2500 at <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi>m</mi><mo>/</mo><mi>z</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="23pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="91270dba487782af7360c80516416e4b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-17-1037-2024-ie00001.svg" width="23pt" height="14pt" src="amt-17-1037-2024-ie00001.png"/></svg:svg></span></span> 208, which helps distinguish between most organic fragment ions and metal ions and facilitates the analysis of complex aerosol particles. For the analysis of individual particles, the increased resolution of the HP-SPAMS contributes to the differentiation of most organic fragment ions and metal ions and facilitates the evaluation of complex aerosol particles, in the case of atmospheric lead-containing particles. The improved detection efficiency and chemical analysis capability of HP-SPAMS will be of great importance for low-concentration aerosol detection and complex aerosol component analysis.</p>
<p>The extensive terrestrial ecosystems of tropical Africa are a significant store of carbon and play a key but uncertain role in the atmospheric budgets of carbon dioxide and methane. As ground-based observations in the tropics are scarce compared with other parts of the world, recent studies have instead made use of satellite observations assimilated into atmospheric chemistry and transport models to conclude that methane emissions from this geographical region have increased since 2010 as a result of increased wetland extent, accounting for up to a third of global methane growth, and that the tropical Africa region dominates net carbon emission across the tropics. These studies critically rely on the accuracy of satellite datasets, such as those from the Orbiting Carbon Observatory-2 (OCO-2), the Greenhouse gases Observing SATellite (GOSAT), and the Sentinel-5 Precursor TROPOspheric Monitoring Instrument (TROPOMI), along with results from atmospheric transport models, over a geographical region where there are little independent data to test the robustness of published results.</p>
<p>In this paper we present the first ground-based observations of greenhouse gas column concentrations over East Africa, obtained using a portable Bruker EM27/SUN Fourier transform infrared (FTIR) spectrometer during a deployment covering the first few months of 2020 in Jinja, Uganda. We operated the instrument near autonomously by way of an automated weatherproof enclosure and observed total atmospheric column concentrations of the greenhouse gases carbon dioxide and methane, as well as carbon monoxide, a useful proxy for emissions from incomplete combustion processes in the region. We discuss the performance of the combined enclosure and spectrometer system that we deployed in Jinja to obtain these data and show comparisons of our ground-based observations with satellite datasets from OCO-2 and Orbiting Carbon Observatory-3 (OCO-3) for carbon dioxide and TROPOMI for methane and carbon monoxide, whilst also comparing our results with concentration data from the GEOS-Chem and Copernicus Atmosphere Monitoring Service (CAMS) atmospheric inversions that provide a means of increasing spatial and temporal coverage where satellite data are not available. For our measurement period, we find mean differences in <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="9f76de9bacc139929cc3e62a82370b59"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-17-5679-2024-ie00001.svg" width="25pt" height="14pt" src="amt-17-5679-2024-ie00001.png"/></svg:svg></span></span> between OCO-2 and the EM27/SUN of <span class="inline-formula">−</span>0.29 % and between OCO-3 and the EM27/SUN of <span class="inline-formula">−</span>0.28 %. In the case of TROPOMI, the mean difference in <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">CH</mi><mn mathvariant="normal">4</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="99fd42f4fe526f13323dfe2a8623f335"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-17-5679-2024-ie00002.svg" width="24pt" height="14pt" src="amt-17-5679-2024-ie00002.png"/></svg:svg></span></span> that we find between TROPOMI and the EM27/SUN is <span class="inline-formula">−</span>0.44 %, whilst for <span class="inline-formula">X<sub>CO</sub></span> the mean difference is <span class="inline-formula">−</span>5.65 %. In each of these cases, the mean difference observed between the satellite and ground-based column concentrations is either close to or within the<span id="page5680"/> precision and accuracy requirements for the respective missions. With regard to the model and reanalysis comparisons with the EM27/SUN column concentrations, we see mean differences from the EM27/SUN of a global GEOS-Chem inversion for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5378229209ed71b793da464d95589d0a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-17-5679-2024-ie00003.svg" width="25pt" height="14pt" src="amt-17-5679-2024-ie00003.png"/></svg:svg></span></span> of <span class="inline-formula">−</span>0.08 %, a regional high-resolution GEOS-Chem inversion for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">CH</mi><mn mathvariant="normal">4</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="bdc5f6580abd10d5554e7c36b32c4c34"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-17-5679-2024-ie00004.svg" width="24pt" height="14pt" src="amt-17-5679-2024-ie00004.png"/></svg:svg></span></span> of <span class="inline-formula">−</span>0.22 %, and the CAMS global reanalysis for <span class="inline-formula">X<sub>CO</sub></span> of <span class="inline-formula">−</span>9.79 %. Our results demonstrate the value of ground-based observations of total column concentrations and show that the combined EM27/SUN and enclosure system employed would be suitable for acquisition of the longer-term observations needed to rigorously evaluate satellite observations and model and reanalysis calculations over tropical Africa.</p>
<p>Atmospheric aerosols impact the Earth's climate system directly by scattering and absorbing solar radiation, and it is important to characterise the aerosol optical properties in detail. This study reports the development and validation of an airborne dual-wavelength cavity-attenuated phase-shift (CAPS) single monitor, named A2S2 (Aerosol Absorption Spectral Sizer), based on the commercial CAPS single-scattering albedo monitor (CAPS-PM<span class="inline-formula"><sub>SSA</sub></span>; Aerodyne), to simultaneously measure the aerosol optical scattering and extinction at both 450 and 630 nm wavelengths. Replaced pressure and temperature sensors and an additional flow control system were incorporated into the A2S2 for its utilisation on board research aircraft measuring within the troposphere. The evaluation of A2S2 characteristics was performed in the laboratory and included the investigation of the signal-to-noise ratio, validation of performance at various pressure levels, optical closure studies and intercomparing with the currently validated techniques. The chamber experiments show that the A2S2 can perform measurements at sample pressures as low as 550 hPa and at sample temperatures as high as 315 K. Based on the Allan analysis results, we have evaluated that the minimum detection limit of the measurements shows that the measurements have a limit accuracy of <span class="inline-formula">∼</span> 2 <span class="inline-formula">Mm<sup>−1</sup></span> at 450 nm and <span class="inline-formula">∼</span> 1 <span class="inline-formula">Mm<sup>−1</sup></span> at 630 nm for 1 Hz measurements of both scattering coefficients (<span class="inline-formula"><i>σ</i><sub>sca</sub></span>) and extinction coefficients (<span class="inline-formula"><i>σ</i><sub>ext</sub></span>). The optical closure study with size-selected polystyrene latex (PSL) particles shows that the truncation error of the A2S2 is negligible for particles with particle volume diameter (<span class="inline-formula"><i>D</i><sub>p</sub></span>) <span class="inline-formula"><</span> 200 nm, while, for the larger sub-micrometre particles, the measurement uncertainty of A2S2 increases but remains less than 20 %. The average factors to correct the truncation error are 1.13 and 1.05 for 450 and 630 nm, respectively. A simplified truncation correction, dependent on the scattering Ångström exponent (SAE), was developed to rectify truncation errors of the future A2S2 field measurement data. The <span class="inline-formula"><i>σ</i><sub>sca</sub></span> and <span class="inline-formula"><i>σ</i><sub>ext</sub></span> measured by the A2S2 show good agreement with the concurrent measured results from the nephelometer and the CAPS particle extinction monitor (CAPS-PM<span class="inline-formula"><sub>ex</sub></span>). The absorption coefficient (<span class="inline-formula"><i>σ</i><sub>abs</sub></span>) derived through the extinction-minus-scattering (EMS) method by the A2S2 also corresponds with the results obtained from the aethalometer. The A2S2 was successfully deployed during an aircraft measurement campaign (Atmospheric ChemistRy Of the Suburban foreSt – ACROSS) conducted in the vicinity of Paris and the surrounding regions. The average SSA measured during the entire ACROSS flight campaign is 0.86 and 0.88 at 450 and 630 nm, respectively, suggesting that light-absorbing organic aerosols play a significant role. The average SAE and absorption Ångström exponent (AAE) varied due to measurements in various pollution conditions. The results presented in this study indicate that the A2S2 instrument is reliable for measuring aerosol <span class="inline-formula"><i>σ</i><sub>sca</sub></span> and <span class="inline-formula"><i>σ</i><sub>ext</sub></span> at both blue and red wavelengths, and it stands as a viable substitute for future airborne evaluations of aerosol optical properties.</p>
Summary. In the modern construction of multi-storey buildings, pile foundations are becoming increasingly common in difficult conditions of weak soils. Modern engineers face the difficult task of choosing design solutions that not only meet modern construction requirements but also ensure economic feasibility in dense urban development and complex geology. One of the most promising methods of solving this problem is the use of soil-cement elements to reinforce the foundation as an alternative to pile foundations. This approach can significantly reduce the cost of constructing foundations and reduce the labor intensity of the processes associated with design and construction due to the simple technology of such elements. The main purpose of the study is to evaluate the physical and mechanical properties of soil cement produced by the drilling and mixing method, as well as to determine its deformation modulus during the construction of a residential building. To determine the modulus of deformation of the reinforced base of a multi-storey residential building, data from engineering and geological surveys were obtained. The geological structure of the territory to the explored depth is based on loams, sandy loams and clays. According to the data obtained, the prolific soil properties were revealed at a depth of 7.5 to 8.4 meters. To achieve this goal, a number of preparatory works were carried out, including the preparation of equipment, in particular the MII-100 device for measuring bending strength with a working range of measurements up to 100 kgf/cm2, as well as the manufacture of prism samples measuring 40x40x160 for laboratory tests. The prepared samples made it possible to implement a full cycle of experimental studies, including strength and deformation tests. The results obtained allowed us to conclude that the deformation modulus of the base reinforced with soil-cement elements increases by 15 times compared to conventional soils. This is an important argument in favor of using soil cement in weak clay soils. The study confirms the high efficiency of using soil cement to strengthen foundations with a methodology for checking the deformation modulus during surveys. Particularly noteworthy is the practical significance of the work, which is to increase the reliability and durability of multi-story buildings. This method can be successfully implemented in modern construction, which will reduce material costs, optimize technological processes and improve the performance of buildings and structures.
Abstract. The peculiarities of the use of small-diameter drill piles in modern construction considered, with an emphasis on their advantages and areas of application in specific conditions. Two main types of piles distinguished: cast-in-place, which characterized by continuous reinforcement and filling with concrete or cement mortar, and composite, where the load transfers to reinforcing elements. Main advantages of small-diameter bored piles noted, including the possibility of performing work in confined spaces, reducing the level of noise and vibrations, a variety of drilling technologies, the possibility of application in geological conditions of varying complexity, etc. Particular attention paid to the areas of application of small-diameter bored piles, including the installation of new foundations, underpinning of existing structures, soil improvement and land-slide protection. The main groups of factors that can influence the choice of small-diameter bored piles as the main design decision for various fields of application considered, including: - physical factors (restricted access, remoteness of the area, distance of piles to existing structures); - subsoil factors (difficult geological conditions, soil liquefaction tendency); - environmental factors (sensitivity to vibration/noise, hazardous or contaminated soils); - necessity of adaptation to existing structures; - load/settlement requirements; - economic factors. Limitations for the use of small-diameter drill piles from the point of view of their efficiency described. An example of the effective practical use of small-diameter bored piles in the confined conditions of dense urban development in close proximity of metro tunnels with increased requirements regarding the level of vibrations and noise considered. The task of minimizing subsidence of the designed residential and office complex and the impact on surrounding buildings and structures solved. The compliance of the adopted design decisions confirmed by means of field tests, as well as using the results of settlements monitoring. Attention focused on the need for further improvement of design approaches and technological solutions to optimize the efficiency of small-diameter bored piles for solving geotechnical problems.
The installation of artificial foundations for industrial buildings and constructions (industrial floors) is becoming more and more relevant in modern construction, as the number of satisfactory sites for development is decreasing, territories with complex geological and hydrogeological conditions are increasingly being used. A high-quality installation of an artificial base should ensure the durability, strength and stability of the structure. When preparing the site and arranging the artificial base, it is necessary to take into account such important factors as the type of soil, the level of groundwater, the expected load on the floor and the type of floor covering. Compliance with the requirements of regulatory and technical documentation, the use of quality materials and professional execution of work are critical for the successful construction of industrial floors. As part of the study, an overview and detailed description of the process of installing an artificial base for industrial floors was carried out on the example of a real construction, a warehouse complex with an area of 35,000 m² in the south-western outskirts of the city of Kyiv. The article highlights that the foundation installation process includes two main stages: site preparation and creation of artificial foundation layers. The preparation of the site includes cleaning and planning of the territory, removing and removing the fertile layer of soil, conducting engineering and geological studies and implementing measures for the engineering protection of the territory. The arrangement of the artificial base includes the compaction of the existing soil layers, the creation of new artificial base layers and their mechanical compaction in combination with the reinforcement of the layers with geosynthetics materials (geogrids). This study emphasizes the importance of a comprehensive approach to site preparation and artificial base installation, which allows for reliable and long-term operation of industrial floors, minimizing the risks of deformation and damage.
In this paper I offer an introduction to group field theory (GFT) and to some of the issues affecting the foundations of this approach to quantum gravity. I first introduce covariant GFT as the theory that one obtains by interpreting the amplitudes of certain spin foam models as Feynman amplitudes in a perturbative expansion. However, I argue that it is unclear that this definition of GFTs amounts to something beyond a computational rule for finding these transition amplitudes and that GFT doesn’t seem able to offer any new insight into the foundations of quantum gravity. Then, I move to another formulation of GFT which I call canonical GFT and which uses the standard structures of quantum mechanics. This formulation is of extended use in cosmological applications of GFT, but I argue that it is only heuristically connected with the covariant version and spin foam models. Moreover, I argue that this approach is affected by a version of the problem of time which raises worries about its viability. Therefore, I conclude that there are serious concerns about the justification and interpretation of GFT in either version of it.