Scopus | Abstract and citation database https://hdl.handle.net/20.500.14124/6559 2026-04-21T21:48:20Z 2026-04-21T21:48:20Z Ahadian, Farnaz Işıkdağ, Ümit Bekdas, Gebrail Niğdeli, Sinan Melih Çakıroğlu, Celal Geem, Zong Woo https://hdl.handle.net/20.500.14124/10662 2026-03-26T07:43:14Z 2026-01-01T00:00:00Z

Interpretable Machine Learning for Compressive Strength Prediction of Fly Ash-Based Geopolymer Concrete Ahadian, Farnaz; Işıkdağ, Ümit; Bekdas, Gebrail; Niğdeli, Sinan Melih; Çakıroğlu, Celal; Geem, Zong Woo Fly ash-based geopolymer concrete (GPC) is a sustainable alternative to conventional cementitious materials; however, its compressive strength is governed by complex and highly correlated mixture parameters, making experimental optimization expensive and data-driven modeling challenging. While machine learning (ML) techniques have been widely applied to predict GPC strength, most studies prioritize predictive accuracy without explicitly addressing multicollinearity among input variables, which can distort feature importance, reduce model stability, and limit engineering interpretability. This study proposes a multicollinearity-integrated and interpretable ML framework that systematically embeds correlation diagnostics and structured feature screening within the modeling pipeline rather than treating interpretability as a post-processing step. Multiple conventional and ensemble learning algorithms were comparatively evaluated using cross-validation to ensure generalization robustness. The proposed framework achieved a maximum coefficient of determination (R2) of 0.96 with low prediction error, outperforming baseline regression models while demonstrating improved stability under correlated input conditions. Unlike existing studies that rely solely on black-box optimization, the integrated interpretability analysis revealed physically consistent dominance of curing temperature, alkali content, and water-related parameters in governing strength development. By explicitly coupling predictive performance with multicollinearity mitigation and engineering-oriented interpretability, this work advances beyond accuracy-driven ML applications and provides a robust and transparent decision-support tool for sustainable geopolymer mix design.

2026-01-01T00:00:00Z Kartal, Asiye Nisa Kartal, Hasan Basri https://hdl.handle.net/20.500.14124/10661 2026-03-26T07:41:45Z 2026-01-01T00:00:00Z

The Multimodal Sensory Perception of Museum Environments: A Qualitative Case Study on the Visual and Haptic Museum Atmosphere in Istanbul Kartal, Asiye Nisa; Kartal, Hasan Basri This study examines individual-centric multimodal sensory experiences in the museum context, where multimodality is defined as the interplay among sensory modalities. Focusing on visual and haptic experiences, the research aims to investigate the role of museum lighting in shaping sensory perception at the Istanbul Museum of Painting and Sculpture. We asked how local museum visitors aged 18-26 (primarily university students and frequent museum-goers) perceive and engage with the museum atmosphere beyond visual stimuli, particularly through lighting. Data were collected through sensorywalks (n = 16), a sensory-spatial research method, and interviews (n = 10) with local museum visitors. Findings indicated that lighting enhances multimodal sensory interactions during museum visits and enhances visitors' awareness of spatial scale, materiality, and atmosphere. The discussion highlighted the significance of sensory-based museum design, including the sensory museum models and toolkits, in rethinking how young adults engage with museum environments. Understanding the multimodal experiences offers valuable insights for advancing both research and practice in museum studies.

2026-01-01T00:00:00Z Şahin, Sibel https://hdl.handle.net/20.500.14124/10660 2026-03-25T07:43:24Z 2026-01-01T00:00:00Z

H(b) Spaces of non-extreme b Over Finitely Connected Planar Domains Şahin, Sibel In this work, density of the algebra A ( D ) $\mathcal{A}\left(D\right)$ in H(b) spaces of finitely connected planar domains and the boundedness of composition operators on these function spaces are studied. Density of the algebra is considered when the defining function b is a non-extreme point of the unit ball of H infinity(D). In the last part boundedness of composition operators on H(b) spaces is considered and as well as a generalization of the unit disk case is given, the boundedness of composition operators with generalized Blaschke symbols over finitely connected domains is characterized.

2026-01-01T00:00:00Z Aydoğdu, Hasan Hüseyin Atasever, Kurtuluş Maeda, Masaki İlki, Alper https://hdl.handle.net/20.500.14124/10659 2026-03-17T08:06:16Z 2026-01-01T00:00:00Z

A Case Study on Seismic Retrofitting of Sub-standard RC Buildings Using FRPS: A Building Damaged During 2023 Kahramanmaraş Earthquakes Aydoğdu, Hasan Hüseyin; Atasever, Kurtuluş; Maeda, Masaki; İlki, Alper Türkiye is located in a very active seismic region and experienced destructive earthquakes frequently in the last century. Despite the high-quality seismic design codes in force in Türkiye starting from 1940, construction without complying with these codes caused catastrophic consequences after every strong earthquake. Most recently, the 2023 Kahramanmaraş earthquakes revealed the poor seismic performance of sub-standard building stock in Türkiye once more. Seismic retrofitting has a critical role in risk reduction worldwide, considering its efficiency in terms of time and cost. Among strengthening alternatives, methods making use of FRPs come forward based on the superior characteristics of FRPs such as high strength, high durability, and lightweight. In this study, the seismic performance of a low-rise RC frame building damaged during the 2023 Kahramanmaraş earthquakes, which reflects the general characteristics of the sub-standard building stock in Türkiye with extremely low compressive strength of concrete, insufficient system rigidity, longitudinal reinforcement, confinement details, and cross-section dimensions of vertical RC elements, is evaluated. Then, to discuss the efficiency of structural strengthening using FRPs in reducing seismic risks of typical sub-standard buildings in Türkiye, the case building was hypothetically retrofitted at various levels of safety considering different intervention strategies. A nonlinear time history analysis with near station records is conducted, and the performance of the building is determined based on 2018 Turkish Building Earthquake Code. Finally, based on the results of this study, the effectiveness of considered intervention strategies is evaluated together with the seismic performance of the building observed after Kahramanmaraş earthquakes.

2026-01-01T00:00:00Z