Point clouds are essential for 3D spatial analysis and widely used in geodesy, photogrammetry, and remote sensing. While modern technologies simplify their collection, processing remains challenging due to data size, irregularity, and noise. Classification is critical for object identification and noise removal. This paper explores geometric features of points derived from their local 3D neighbourhoods. It examines neighbourhood definitions, feature computation via principal component analysis (PCA), and their impact on real dataset classification. Using a test point cloud with natural and anthropogenic features, we analyze feature dependencies, identify redundancies, and highlight key metrics. Additionally, we propose new approaches for noise filtering, contributing to more efficient point cloud processing and practical applications. Received: 02.12.2024 Received in revised form: 20.01.2025 Accepted: 14.02.2025
The study evaluates the effectiveness of various ecological slope protection strategies for riverbank stabilization by systematically analyzing several critical factors: slope coefficient, durability, impact resistance to flow, biodiversity index, biochannel fluency, vegetation coverage, construction and maintenance costs, landscape aesthetics, and recreational function. The Fuzzy Set Pair Analysis Assessment Method was utilized to create a comprehensive evaluation model, employing normalized benefit-type indices and incorporating the Analytic Hierarchy Process (AHP) with an Accelerated Genetic Algorithm (AGA) to determine the weight of each evaluation index. This model assesses the linkage degree of single indices and uses a confidence criterion to classify evaluation samples across different risk tolerance levels. The results show that plant berms are most effective at a confidence level of 0.50, while gabion revetments perform best at levels of 0.60 and 0.70. The findings suggest that plant berms are suitable for higher risk tolerance, while gabion revetments are better for risk-averse decisions. This methodology offers a novel and robust tool for scientifically assessing and selecting optimal river slope protection strategies.
This paper introduces a set of new criteria for assessing the energy-efficiency potential of multilayered building envelopes, focusing on physically measurable aspects of dynamic thermal performance and LCA parameters. Based on EN ISO 13786:2023, the study considers thermal transmittance (U-value), internal areal heat capacity (k1), and decrement factor (f) as thermal performance parameters, along with assembly mass (m) and embodied energy (EE) as additional LCA objective indicators. Five wall assemblies common in the Ukrainian market-hempcrete, AAC + Rockwool, Porotherm brickwork + Rockwool, wood-chip cement-bonded blocks (Woodcrete) and ICF systems were evaluated through numerical modelling and comparative analysis. To eliminate subjectivity in criteria weighting, three new interconnected criteria were proposed: Dynamic Thermal Performance Efficiency per mass (DTPEm), per embodied energy (DTPEEE), and per both (DTPEm&EE). Results indicate that AAC + Rockwool (Wall B) consistently ranks as the most efficient assembly according to the DTPEm&EEcriteria. At the same time, Wall E (ICF) aligns with the recommended thermal inertia ranges but exhibits the highest embodied energy, resulting in the lowest DTPEm&EE. The study highlights the complexity of MCDA in envelope design and provides physically grounded criteria that can support more objective predesign decision-making.
In the context of modern architecture, glass is widely regarded as a fundamental design element, representing a material of increasing interest to architects and engineers. The fundamental challenge in using glass is to design convenient connections. Adhesive joints are more convenient connections compared to mechanical fixings due to ensuring uniform stress distribution. This study focuses on small glass-to-glass specimens: (i) bonding of the specimens, (ii) artificial ageing, and (iii) shear tests. Two different transparent adhesives were tested, 2-component epoxy and UV-cured acrylate. Proper specimen bonding is essential. Two-component epoxy required careful sealing during curing to prevent leakage. The UV-cured acrylate adhesive needed a careful curing process to avoid bubble formation due to shrinkage of the adhesive. To determine resistance to environmental effects, a combination of DVS 1618 procedure and UV radiation was used for artificial ageing of specimens. Shear tests on the reference set showed excellent results for the acrylate adhesive, which achieved an average shear strength of 10.17 MPa. Problems with adhesion appeared after artificial ageing. Epoxy adhesive achieved an average shear strength of 4.55 MPa in the reference set. Two specimens had problems with adhesion to glass. After ageing, the specimens achieved a higher average shear strength (4.86 MPa) than in the reference set. The aged specimens failed only by glass breakage. Both adhesives showed high potential for use in glass construction joints.
In this study, to investigate the cracking resistance of UHPC-strengthened simply-supported-to-continuous concrete box beams in the negative moment zone, a total of nine specimens were designed: one reinforced concrete box beam (comparison beam), seven UHPC-RC composite box beams (reinforced beams), and one prestressed concrete box beam (prestressed beam). The research focuses on evaluating the influence of key parameters-including reinforcement ratio, UHPC casting length in the negative moment zone, UHPC thickness, and the joint configuration between UHPC and ordinary concrete-on the cracking resistance of these beams. The results demonstrate that, under the same reinforcement ratio, UHPC strengthening in the negative moment zone significantly enhances the cracking performance of the test beams, with the cracking load increasing by 46%. As the UHPC casting length increases, the maximum crack width at the vertical interface between the full normal concrete (NC) section and the UHPC-NC composite section decreases markedly. Additionally, increasing the UHPC thickness leads to a substantial reduction in the maximum crack width at both the UHPC-NC composite section and the intermediate diaphragm section.
