[article-cris] Insinööritieteiden korkeakoulu / ENG

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Enhancing urban vitality : integrating traditional metrics with big data and socio-economic insights
(2024) Osunkoya, Kofoworola Modupe; Partanen, Jenni
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
A city is an intricate system where interactions between transport, land use, the environment, and the population occur at various scales. This complexity makes it challenging to predict and govern these interactions. However, big data on human activity patterns allows researchers to discover dynamic, temporary patterns in the activity landscape and understand the choreographies of people’s behavior to enhance urban areas’ vitality through planning. In this article, we hypothesized that a higher diversity of urban spatio-functional and socio-economic features indicates higher urban vitality in Tallinn, Estonia. We explored multi-sourced indexes to interpret this formation of urban vitality using complex agent variables of location, cluster, diversity, and similar actors generating self-organizing patterns of urban life. We used functional and morphological components and socio-economic data identified as traditional, ‘slow’ vitality measures (SM), and mobile phone location data as dynamic metrics (DM), respectively. We analyzed them in a geographic information system (GIS) environment to measure the types of spatial configurations, temporal variation of vital places, and their correlation. The results indicate a positive correlation (r= 0.5116) between the slow metrics and the high mobile phone activity. These correlations demonstrate that cell phone data provides a detailed and accurate view of people’s daily rhythms and choreographies. The diversity indicators offer a new method to interpret urban vitality in cities and make planning decisions that support its emergence.
A tale of four studios: Evolving planning and architecture education towards mixed modality in a post-pandemic world
(2024-07) Hewidy, Hossam; Purkarthofer, Eva; Eräranta, Susa
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The COVID-19 pandemic imposed urgent challenges for educational institutions. The sudden shift from on-site teaching to online distance learning offered the possibility to examine new settings of the studio, a core element of planning and architecture education. Although the pandemic is now over, online learning has secured a fixed place in university education, and consequently, educational institutions need to reconsider studio education based on the lessons learned during the pandemic. Through studying four studios taught at Aalto University, Finland, in 2020 and 2021, this article examines student-teacher experiences, and proposes opportunities for evolving studio education. The findings show that distance learning has in general sustained the objectives of studio education. However, challenges remain especially regarding the social aspects of learning. The degree of success of online teaching varied greatly depending on the tasks and the orientation of the studio (design or strategy). Technological aids and devices also had an influence on fulfilling the pedagogical objectives of learning. Professional socialization was highly affected by the online environment both in design and planning studios and the architectural representation witnessed difficulties specifically in design studios. To evolve the studio setting, the article suggests a mixed modality model supporting the social dimension of studio teaching by combining on-site and online learning activities to enrich the learning process. Such a model can harmonize the intended learning objectives and activities with the teaching methods and modality, thus improving the social dimension of studio teaching.
Evaluating the strength, durability and porosity characteristics of alluvial clay stabilized with marble dust as a sustainable binder
(2025-03) Hanafi, Mohamad; Javed, Israf; Ekinci, Abdullah
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
High-plasticity soils such as alluvial clay deform easily under heavy loads due to their strong plastic behavior. The tendency of these soils to expand and contract can cause deformation and cracking in structures, posing challenges in construction. To address these challenges, it's essential to improve these soils to enhance their strength and reduce plasticity before construction. Therefore, this study aims to evaluate the applicability of marble dust as a sustainable alternative to Portland cement in ground improvement applications, specifically to improve the behavior of alluvial clay. The performance of marble dust, Portland cement, and alluvial clay mixtures was evaluated using unconfined compressive strength (UCS), shear wave velocity, and mass loss due to weathering. The study tested three Portland cement contents (7, 10, and 13 %), two dry density (1.6 and 1.8 g/cm3), and two marble dust contents (0, 10 and 20 %) across three curing ages (7, 28, and 60 days). Microstructural analysis was performed using SEM. Results indicated a slight decrease in 7-day strength (up to 8.3 %) with 10 % marble dust replacement due to minimal pozzolanic activity, while 28-day strength loss was less significant. On the other hand, the 60-day strength increased up to 20 % upon replacing 10 % of cement with marble dust. The marble dust addition also increased the shear modulus of the soil by up to 9 % when compared with cement only. The adjusted porosity index of 0.32 correlated unconfined compressive strength (qu), initial shear modulus (G0), and accumulated loss of mass (ALM) across varying densities and blend proportions. ALM increased linearly with wet-dry cycles, with higher compaction and binder content reducing mass loss per cycle. More marble dust, however, led to greater mass loss at both curing ages, attributed to reduced cement content.
Promises and perils of water sensitivity as a new hydro-social imaginary for Kozhikode, India
(2025-02) Silva, Raquel H.; van der Meulen, Geert J.M.; Zwarteveen, Margreet Z.; Stead, Dominic; van Dorst, Machiel J.; Bacchin, Taneha K.
A2 Katsausartikkeli tieteellisessä aikakauslehdessä
Water-Sensitive Urban Design (WSUD) proposes integrating the management of urban water cycles into urban planning and design as a strategy to better respond to water challenges in the urban environment. Proposed frameworks try capturing urban water sensitivity in terms of generic, transferable principles. In this article, we trace the water history of Kozhikode in India to make a plea for epistemic justice and context-specificity in the definition of water sensitivity, recognizing how the quality and direction of contemporary urban water flows are the outcome of particular – (post-)colonial, neo-liberal – histories. We mobilize insights from political ecology to do this. Concepts like waterscapes and hydro-social imaginaries help acknowledge that waters and cities co-evolve to create often highly uneven waterscapes. This usefully denaturalizes and thereby politicizes urban water sensitivity, giving much-needed prominence to the ‘who’ questions: who will benefit (most), and who will stand to lose? For Kozhikode, with its fishing enclaves, sacred groves, ponds, and a colonial canal crossing its coastal plain, treating water sensitivity as a mere techno-managerial question risks reinforcing middle-class dominance and aspirations, while also provoking ecological decay.
Alkusanat
(2024) Niiranen, Jarkko
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Compact city and urban planning : Correlation between density and local amenities
(2025-01) Jama, Teemu; Tenkanen, Henrikki; Lönnqvist, Henrik; Joutsiniemi, Anssi
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Many scholars and planners emphasise the role of compact cities in sustainable urban development. Compact urban form is seen as a way to encourage people, for example, to drive less and walk more, which reduces transport-related GHG emissions. This argument, however, is strongly dependent on local amenity development that can support such local living. In plan-making, a common practice is to try to ensure the realisation of services with a high Gross Floor Area (GFA) residential infill development to raise the local population density. In this paper we are seeking quantitative insight on the resolution under which urban density, as measured by GFA volume, correlates with the growth of urban amenities and liveability. Specifically, we are seeking the direction in which correlation changes when moving from a larger geographical scale (low resolution) towards a smaller scale (high resolution) of walkable reach. Our study shows a clear correlation between urban amenities and planned GFA at low-resolution scales, but that correlation decreases at higher-resolution scales (walkable neighbourhood level), indicating that urban amenities tend to cluster in different locations than density is planned. Based on these findings, we argue that, if the aim of urban planning is to foster the growth of local amenities, it should shift its focus towards larger patterns of urban development rather than emphasising GFA in detailed plan-making.
Sustainable Materials and Structures Used in Pavement Engineering
(2025-01) Guo, Fucheng; Cannone Falchetto, Augusto; Zhou, Bochao; Wang, Wentong
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
A simulation-based framework for quantifying potential demand loss due to operational constraints in automated mobility services
(2025-02) Agriesti, Serio; Roncoli, Claudio; Nahmias-Biran, Bat hen
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Automated vehicles are key to unlock a more widespread on-demand service, increasing accessibility also in peripheral areas of large cities. To evaluate how the performance of these services may affect the overall demand in return, multiple dimensions of the transport problem have to be considered. Indeed, despite people may be willing to use Automated Mobility On-Demand (i.e., generating a potential demand for the service), they may be less willing to consistently replace their other travel options if they, for example, experience high waiting times (determined by the performance of the service, i.e., the supply). In this study, we propose a simulation-based framework developed by integrating an activity-based and a dynamic traffic assignment model, designed to frame absorbed and lost demand at a disaggregated level. This allows capturing how the effects of network congestion and fleet constraints may cause a certain portion of the demand to shift to traditional modes of transportation, thus improving, for example, the accuracy of business cases for mobility service design or of hidden patterns of inequality for policymakers and public authorities.
Revealing Stachybotrys-like fungal growth in buildings - Possible exposure highlighted through three case studies
(2025-01-20) Hintikka, Tuomas; Andersson, Maria A.; Marik, Tamás; Mikkola, Raimo; Andersson, Magnus; Kredics, László; Kurnitski, Jarek; Salonen, Heidi
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Genus Stachybotrys (Stachybotryaceae, Hypocreales) requires high humidity to grow and represents one of the most notorious fungi associated with suspected illness in moist buildings. If Stachybotrys conidia are found in settled indoor dusts, their presence may indicate water intrusion and mold infestation revealed after dismantling the building structures. This study describes detection of Stachybotrys growth hidden inside the structures of three buildings in Finland. First, a novel microscopic screening method concentrating Stachybotrys conidia from settled dust was developed. The method is based on enrichment of conidia floating in the solution of saturated NaCl, separating them from sinking dust particles. Captured conidia were identified based on morphology and cultivated isolates were identified to species or genus level. The second part of the study describes the records of two persons sickened with asthma after exposure to long lasting growth of Stachybotrys in two of the buildings. After 38 years of the diagnosis the one person's asthma was declared cured in a medical report. The asthma of the other person developed into chronic illness, diagnosed by The Insurance Court as occupational asthma caused by a moisture-damaged workplace. Diversity and the metabolic activity of the microbes exposing the two persons in rural versus urban environments after their asthma diagnosis is offered as a preliminary and hypothetical explanation of the different outcome of the illnesses.
Assessment of near-surface undrained shear strength of soft seabeds with free fall cone penetrometer testing in the northern Baltic Sea
(2025-02-21) Saresma, Maarit; White, David J.; Mohapatra, Debasis; Mohammadi, Saeideh; Sołowski, Wojciech; Korkiala-Tanttu, Leena; Virtasalo, Joonas J.; Gourvenec, Susan
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Free fall cone penetrometer testing (FFCPT) allows for efficient site reconnaissance and soft seabed undrained shear strength (su) assessment in a shallow water environment. The FFCPT is a particularly useful tool for near-surface characterization for cable route assessment associated with offshore renewable developments. This study presents results from an in-situ FFCPT, seismoacoustic survey and sediment coring campaign in a nearshore site in the Gulf of Finland, northern Baltic Sea. An extended FFCPT interpretation model has been applied, including friction on the shaft (as well as tip resistance), rate dependency and soil buoyancy. The derived FFCPT profiles are repeatable at a given location, while the shapes of the su profiles capture different depositional environments. The derived dynamic FFCPT su is lower than measured in the laboratory by fall cone and triaxial tests. This is potentially due to hydrodynamic drag reducing the FFCPT terminal velocity and soil drag affecting the penetration depth and dynamic su; and due to the reconstituted nature of the laboratory samples and very low stress levels being considered that are difficult to achieve in the laboratory. The magnitude of derived su and characteristic shapes in the FFCPT profiles enable ground-truthing the interpretation of seismoacoustic profiles. This study contributes to the evidence base supporting the FFCPT as a valuable supplement, or to partially replace sediment coring and laboratory measurements, for offshore site assessment.
Explainable machine learning (XML) framework for seismic assessment of structures using Extreme Gradient Boosting (XGBoost)
(2025-03-15) Gharagoz, Masoum M.; Noureldin, Mohamed; Kim, Jinkoo
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
In the field of structural engineering, optimizing retrofitting strategies for bolstering seismic resilience stands as a pressing challenge. Existing methods are often limited by the time-intensive nature of nonlinear time history (NLTH) analysis and the lack of transparency in machine learning (ML) techniques. This study presents an innovative framework for optimizing retrofitting strategies in structural engineering to enhance seismic resilience. The framework integrates eXtreme Gradient Boosting (XGBoost) and the Spring-Rotational Friction Damper (SRFD) retrofit system, known for its ability to dissipate seismic energy and incorporate self-centering mechanisms. The approach improves transparency in machine learning processes and streamlines design optimization. It uses eXplainable Artificial Intelligence (XAI) methods, such as SHapley Additive exPlanations (SHAP) and Local Interpretable Model-agnostic Explanations (LIME), to provide insights into model predictions and ensure clear decision-making processes. The framework uses data-driven optimization to tailor design parameters to specific seismic hazards, enhancing seismic resilience. Its accuracy was validated through a comprehensive analysis, showing low residual errors, favorable learning curves, and a mean squared error (MSE) of 0.00142. The research evaluates the framework using 2D and 3D case study structures, comparing metrics like maximum displacement, residual drift, maximum inter-story drift (MIDR), and energy dissipation. The seismic performance evaluation confirmed the effectiveness of the design procedure for determining optimal retrofit system parameters estimated by the eXplainable Machine Learning (XML) framework. This represents a significant advancement in seismic assessment methodologies, enabling engineers to make informed decisions about building safety and promoting the adoption of ML-based approaches in earthquake engineering.
Ionic thermoelectric performance of cement and its modifications
(2025-07) Yossef, Mostafa; Kuva, Jukka; Mousavihashemi, Seyedabolfazl; Ward, Andrew; Perry, Marcus; Kallio, Tanja; Puttonen, Jari
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Ionic thermoelectric materials integrated into the concrete members of buildings have potential to generate electric energy utilizing thermal gradients. This paper investigates the effects of nickel foam (NF)-carbon nanotube (CNT) electrodes and the polyvinyl alcohol (PVA) hydrogel on the thermoelectric performance of hardened cement and evaluates the use of PVA as a charge carrier between the CNT electrodes and cement. The porosity of the cement samples was studied using micro-computed tomography. The results indicate that modifying the cement with PVA hydrogel increases capillary porosity while it reduces the Seebeck coefficient, overall strength, and capacitance. The increase of porosity observed to decrease the thermoelectric power. Pure cement samples without any modifications produced significant values up to 28 mV/K for the Seebeck coefficient, which can be explained by the diffusion of water inside the CNT nanochannels and its flow in cement microcracks and capillaries. These values pave the way for energy-efficient housing with increased grid independence.
Comprehensive performance evaluation of satellite-based and reanalysis rainfall estimate products in Ethiopia : For drought, flood, and water resources applications
(2025-02) Wodebo, Desta Yoseph; Melesse, Assefa M.; Woldesenbet, Tekalegn Ayele; Mekonnen, Kirubel; Amdihun, Ahmed; Korecha, Diriba; Tedla, Hailay Zeray; Corzo, Gerald; Teshome, Asaminew
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Study Region Ethiopia: This study assessed the accuracy of ten satellite-based and reanalysis rainfall estimation products across Ethiopia via direct comparisons with 430 in-situ datasets from 2001 to 2020. The performance of these rainfall products at various spatial and temporal scales was validated via five continuous and six categorical metrics to identify the most reliable products for the application of drought monitoring, flood risk analysis, and water resources management in 92 zonal administrative and 76 subbasins boundaries in Ethiopia. New hydrological insights for the region: This study revealed that the performance of rainfall products varies over space and time and is heavily impacted by the diverse climate and topography of Ethiopia. In general: ARCv2.0 and CHIRPSv2.0 detected rainfall of less than 1 mm and well-captured drought-year monthly products, making them suitable for drought monitoring. The IMERG-Fv6B and TAMSATv3.1 products were found to be reliable for detecting heavy rainfall and suggested for flood monitoring. Similarly, for water resources potential studies, CHIRPSv2.0 and MSWEPv2.8 were identified as reliable products at all 50 spatial scales of the analysis. This study offers multiple novel perspectives for selecting location-specific suitable rainfall products as decision-support information for water resources, flood risk management, and drought monitoring in Ethiopia. The findings also imply the importance of bias correction or blending of satellite data for a better representation of the true value.
Evaluating multiannual sedimentary nutrient retention in agricultural two-stage channels
(2025-12) Västilä, Kaisa; Jilbert, Tom
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The two-stage channel (TSC) design with a vegetated man-made floodplain has been recommended as an alternative to conventional re-dredging for managing suspended sediment (SS) and nutrient loads in agricultural streams. However, there are currently uncertainties surrounding the efficiency of TSCs, since mass balances covering the whole annual hydrograph and including different periods of the channel life cycle are lacking. This paper aims to improve understanding of the medium-term morphological development and sedimentary nutrient retention when a dredged, trapezoidal-shaped channel is converted into a TSC, using a mass balance estimate of nutrient and carbon retention from immediately after excavation until the establishment of approximate biogeochemical equilibrium retention. We developed a framework allowing estimation of the sedimentary net retention of phosphorus (P), nitrogen (N) and carbon (C) considering the differences in the initial and mature biogeochemical conditions in topsoil between different channel parts. Further, we conducted repeated elevation surveys and analyses of vertical sedimentary elemental chemistry over a 9-year period to apply the framework at a pilot site in Southern Finland. The pilot TSC floodplain significantly retained SS and nutrients while the low-flow channel did not suffer from siltation, supporting the hypothesized enhanced self-cleansing capacity of TSCs compared to trapezoidal cross-sections. Because of the flushing of the earlier bed deposits, there was net release of SS, P, and N over the first 9 years in the entire TSC system. Depending on the element and channel part considered, physical deposition constituted 13‒79% of the net retention on the newly exposed, excavated surfaces, while the remainder could be attributed to biogeochemical retention, enriching the topsoil in nutrients and carbon. The developed framework is highly suitable to assess the medium-term sedimentary nutrient retention in TSC systems. As a novelty, the framework improves the reliability of the retention efficiency evaluation compared to the typically used snapshot water quality sampling and allows prioritizing the required sediment coring at further TSC sites. The results allow heterogeneities in the process rates to be quantified and potential inefficiencies in nutrient retention due to channel design and morphology to be identified.
Experimental and numerical characterization of hydro-mechanical properties of rock fractures : The effect of the sample size on roughness and hydraulic aperture
(2025-02) Torkan, Masoud; Uotinen, Lauri; Baghbanan, Alireza; Rinne, Mikael
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This paper investigated fluid flow in low-stress conditions through rock fractures in Kuru granite measuring 25 cm × 25 cm. Physical aperture and roughness were measured using high-precision photogrammetry. Anisotropy in roughness was observed in two perpendicular directions. Physical aperture under normal stresses was measured, and fracture closure was compared with linear variable displacement transducer (LVDT) measurements, showing good agreement. Hydromechanical tests exhibited nonlinear behavior between fluid pressure gradient and flow rate, following the Forchheimer equation. Applying normal stress resulted in decreased hydraulic aperture and increased nonlinearity of fluid flow. Experimental hydromechanical tests also revealed anisotropy in perpendicular directions, aligning with fracture roughness measurements. Photogrammetric models, aided COMSOL simulations, closely matched the experimental results. Increased stress induced channeled flow and greater tortuosity. Validation of the numerical model allowed simulations on larger fractures. A 2 m × 1 m granite fracture studied scale effects, with the rough surface duplicated and shifted by 350 μm to align with initial aperture measurements of 25 cm × 25 cm samples. Fluid flow simulations assessed subsample sizes (5 cm–100 cm), showing size-dependent variations in roughness, hydraulic aperture, and non-Darcy coefficient, stabilizing beyond 30 cm. This underscores sample size's role in parameter stabilization beyond a 30 cm scale.
INTEGRATING CLIMATE POLICY OBJECTIVES INTO MUNICIPAL LAND POLICIES: From conceptualization to empirical evidence from Finland
(2025-01) Puustinen, Tuulia; Falkenbach, Heidi; Ekroos, Ari; Junnila, Seppo
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Urban development ties in closely with climate change mitigation and adaptation. However, little is known about how climate policy objectives are incorporated into municipal land policies. Addressing this knowledge gap, we draw from the literature on policy integration and policy design to propose a framework for conceptualizing the ways in which policy objectives driven by climate concerns are incorporated into land policy. This framework incorporates three dimensions: 1) the alignment and prioritization of climate policy objectives in land policy; 2) the concreteness of the final integrated policy design; and 3) the commitment to promoting the objectives set through choices of policy instruments. We apply this framework to explore the level of integration in 30 highly populated municipalities in Finland. We identify three levels of climate policy objective integration within this sample, with only three municipalities demonstrating high integration. Our findings suggest that raising the level of climate policy integration into land policy may require institutional support.
Towards sustainable urban transport—Political agenda formation and policy windows in Helsinki, Oslo, and Stockholm
(2024-12) Karjalainen, Linda E.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This paper examines the development of urban transport political agendas in three Nordic capital cities, Helsinki, Oslo, and Stockholm, that strive towards urban sustainability. Utilising the Multiple Streams framework as a basis for analysis, an overview of local problems, policy solutions, and politics that have characterised transport systems and the related policy development processes over time is constructed. The attention is then drawn towards the points in time where the streams connect, and policy windows occur, to detect formative changes and their enablers towards sustainability. The data consists of 18 semi-structured expert interviews, conducted amongst municipal policymakers and planners. The results reveal several policy windows that have transformed the local transport systems towards sustainability and an increasingly people-oriented approach. The relevance of global climate change awareness, international planning trends for liveability and cycling, public pressure, individual political decisions, and establishment of modal hierarchy is evident across the case cities, while car traffic regulation is politically challenging and addressed through very different means at very different times. The findings of this paper outline diverse ways for advancing sustainability in local policy development but also detect methods for politically halting the process.
Smart Readiness Indicator : Ready for Business? Evidence from a Northern EU Country
(2024-11) Autio, Pauli; Borgentorp, Eerika; Pulkka, Lauri; Junnila, Seppo
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This paper aims to evaluate how well the increasingly popular, market-based real estate energy efficiency improvement projects support the EU’s high-level smart energy transition targets. The implications of these EU-level targets for buildings are described in the smart readiness indicator (SRI) framework. As the SRI becomes mandatory, it is important for the industry to understand whether current market practices align with the SRI framework. This study is based on a qualitative analysis of 49 energy efficiency improvement project proposal reports for properties located in Finland. We use the SRI framework to evaluate the potential impact of the various energy efficiency improvements proposed in the reports on the smart energy transition targets. Three expert interviews were also conducted to gain the interviewees’ interpretations of the industry. While energy efficiency improvement projects are obviously aimed at improving energy efficiency, the results indicate that they are beneficial for some parts of the SRI, mainly within the SRI’s main categories of heating, controlled ventilation, and monitoring and control. Some proposed actions also contribute to increased smart readiness in the categories of cooling and lighting, but the remaining four main categories are generally not being taken into consideration.
Characterization of oxygen initiation process in the autothermic pyrolysis in-situ conversion of Huadian oil shale
(2024-12) Xu, Shao Tao; Lü, Xiao Shu; Wang, Han; Sun, You Hong; Kang, Shi Jie; Wang, Zhen Dong; Guo, Wei; Deng, Sun Hua
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The oxygen initiation process, one of the key processes in the early stage of the autothermic pyrolysis in-situ conversion technology, has not been deeply investigated, which seriously limits its development. In this study, the reaction behaviors, kinetic parameters, heat and product release characteristics during the isothermal oxygen initiation process of Huadian oil shale in O2/N2 mixtures with different oxygen concentrations and initiation temperatures were investigated via TG/DSC-FTIR. The results show that the samples exhibit three different reaction behaviors during the initiation stage, consisting of two main parts, i.e., the oxidative weight-gain and the oxidative reaction phases. The former phase is mainly characterized by the oxygen addition reaction that produces oxidizing groups which increase the sample mass. And the latter stage consists of two main subreactions. The first subreaction involves the oxidative cracking and pyrolysis of oxidizing groups and kerogen to produce fuel deposits such as residual carbon, while the second subreaction focuses on the oxidation of the resulting fuels. Furthermore, increasing the oxygen concentration significantly promotes the above reactions, leading to an increase in the reaction intensity and reaction rate. Owing to the combined effect of oxygen concentration and residual organic matter content, the total heat release increases with the increasing initiation temperature and reaches its maximum at 330–370 °C. In addition, the preheating stage primarily produces hydrocarbon gases, while the initiation stage predominantly generates CO2. As the preheating temperature increases, the CO2 output intensifies, the required reaction time shortens, and the release becomes more concentrated. Based on these findings, a reaction mechanism for the oxygen initiation process of Huadian oil shale was proposed, and recommendations were provided for optimizing the construction process.
Data-driven model for seismic assessment, design, and retrofit of structures using explainable artificial intelligence
(2025-01-20) Shabbir, Khurram; Noureldin, Mohamed; Sim, Sung Han
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Retrofitting building designs is crucial given the global aging infrastructure and increased in frequency of natural hazards like earthquakes. While traditional data-driven models are widely used for predicting building conditions, there has been limited exploration of recent artificial intelligence (AI) techniques in structural design. This study introduces a novel explainable AI framework that utilizes data-driven models for assessing, designing, and retrofitting of structures. The framework highlights the key global features of the model and further investigates them locally to adjust the input design parameters. It suggests the necessary changes in these inputs to achieve the desired structural performance. To achieve this, the framework employs interpretability techniques such as feature importance, feature interactions, Shapley Additive exPlanations, local interpretable model-agnostic explanations, partial dependence plot (PDP), and individual conditional expectation to highlight the important features. Additionally, a novel counterfactual) technique is applied for the first time as a design tool in seismic assessment and retrofitting of structures. The effectiveness of this framework is validated on a real benchmark structure through nonlinear time history analysis and natural earthquakes. The results show that the proposed framework is highly effective, especially under design-level earthquake conditions in achieving the necessary change in stiffness and strength of structures to meet the required seismic design objectives across different earthquake scenarios. This framework holds promise for wider adoption and applications in various other structural and civil engineering domains.

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