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Imagery from Unmanned Aerial Vehicles can be used to generate three-dimensional (3D) point cloud models. However, final data quality is impacted by the flight altitude, camera angle, overlap rate, and data processing strategies. Typically, both overview images and redundant close-range images are collected, which significantly increases the data collection and processing time. To investigate the relationship between input resources and output quality, a suite of seven metrics is proposed including total points, average point density, uniformity, yield rate, coverage, geometry accuracy, and time efficiency. When applied in the field to a full-scale structure, the UAV altitude and camera angle most strongly affected data density and uniformity. A 66% overlapping was needed for successful 3D reconstruction. Conducting multiple flight paths improved local geometric accuracy better than increasing the overlapping rate. The highest coverage was achieved at 77% due to the formation of semi-irregular gridded gaps between point groups as an artefact of the Structure from Motion process. No single set of flight parameters was optimal for every data collection goal. Hence, understanding flight path parameter impacts is crucial to optimal UAV data collection. [ABSTRACT FROM AUTHOR]

Abstract: This paper introduces a new, octree-based algorithm to assist in the automated conversion of laser scanning point cloud data into solid models appropriate for computational analysis. The focus of the work is for typical, urban, vernacular structures to assist in better damage prediction prior to tunnelling. The proposed FaçadeVoxel algorithm automatically detects boundaries of building façades and their openings. Next, it checks and automatically fills unintentional occlusions. The proposed method produced robust and efficient reconstructions of building models from various data densities. When compared to measured drawings, the reconstructed building models were in good agreement, with only 1% relative errors in overall dimensions and 3% errors in openings. In addition, the proposed algorithm was significantly faster than other automatic approaches without compromising accuracy. [Copyright &y& Elsevier]

Dilapidation surveys may require extensive resources to achieve detailed accounts of damage for intervention purposes or may involve only limited resources but be restricted to an extremely rapid assessment (e.g., post-earthquake, life-safety inspection). Neither provides a holistic, cost-effective approach for evaluating the general health of a large number of structures, as is needed for urban planning, historic designation determination, and risk assessment due to adjacent construction work. To overcome this limitation, index images are introduced for a systematic approach for rapidly conducting large-scale, dilapidation surveys of historic masonry buildings. This method, the University College Dublin Inspection Method (UCDIM), is tested against both a detailed inspection and an alternative rapid approach to determine accuracy and resource intensiveness through its application by three inspectors of various levels of experience to six buildings in the city centre of Dublin, Ireland. The UCDIM provided a damage ranking of ρ = 0.94 for all inspectors, regardless of experience, except when painted or rendered facades were included. The UCDIM, compared with detailed inspection, provided a high level of reliability, cost-savings of approximately 90% and several months of time savings since interior access was not required. [ABSTRACT FROM PUBLISHER]

This paper presents the fundamental mathematics to determine the minimum crack width detectable with a terrestrial laser scanner in unit-based masonry. Orthogonal offset, interval scan angle, crack orientation, and crack depth are the main parameters. The theoretical work is benchmarked against laboratory tests using 4 samples with predesigned crack widths of 1–7mm scanned at orthogonal distances of 5.0–12.5m and at angles of 0°–30°. Results showed that absolute errors of crack width were mostly less than 1.37mm when the orthogonal distance varied 5.0–7.5m but significantly increased for greater distances. The orthogonal distance had a disproportionately negative effect compared to the scan angle. [ABSTRACT FROM AUTHOR]

Highlights: [•] Holistic approach to building risk assessment for tunnelling works is proposed. [•] Both cultural and physical building vulnerability criteria are incorporated. [•] Class A prediction presented for Metro North project in Dublin, Ireland. [•] Some 14% of buildings are classified at risk levels of ‘unacceptable’ or ‘unwanted’. [•] Comparison to the official EIS highlights the benefit of such an approach. [ABSTRACT FROM AUTHOR]

This paper compares the feasibility of classifying building façade materials in situ via a low-cost multispectral imaging camera with 5 bands compared to a high-cost, short-wave infrared hyperspectral unit with 240 bands. The sensors were used to classify five common façade materials: brick, mortar, stone, painted window frames, and rendering. The data were subjected to a Partial Least Squares Discriminant Analysis by selecting 95 training pixels and 65 validation pixels for each material. Across all materials, the hyperspectral imaging demonstrated a moderate advantage over multispectral imaging (with a correct classification rate of 99% versus 80%) for the selected data and stronger qualitative matching to the entire façade. While the hyperspectral data were consistently superior, the multispectral data still produced valuable results, thereby demonstrating potential as a fast, easy, and much cheaper technology compared to hyperspectral units for in situ façade materials classification. • Compares façade materials via two imaging cameras of different spectral ranges. • Short-wave Infrared hyperspectral camera compared to 5 band multispectral camera. • Data subjected to a Partial Least Squares Discriminant Analysis for classification. • Hyperspectral accuracy 99% versus multispectral 80%. • Demonstrated multispectral as a potential fast, easy, and cheap alternative. [ABSTRACT FROM AUTHOR]

In bridge design, economically addressing large, lateral earth pressures on bridge abutments is a major challenge. Traditional approaches employ enlargement of the abutment components to resist these pressures. This approach results in higher construction costs. As an alternative, a formal approach using ground anchors to resist lateral soil pressure on bridge abutments is proposed herein. The ground anchors are designed to minimise lateral forces at the pile cap base. Design examples for high stem abutments (heights 6-8 m) are conducted for a simple 33 m long concrete bridge span, with two to three traffic lanes. The abutments are supported by driven, reinforced concrete piles. As lateral forces at the pile cap are significantly reduced, only one row of piles is needed. When compared with common abutment design, the proposed approach halved the number of piles required and decreased the required abutment volume by 37%. [ABSTRACT FROM AUTHOR]

Increasingly, remote sensing is being used as the basis for computational models. With new approaches rapidly emerging, questions arise as to how to validate and assess the resulting models, as they tend to include at least some level of geometric inexactitude. This paper proposes a set of parameters and procedures for evaluating the usefulness of computational models for structural analysis of historic facades subjected to adjacent construction work. To test the usability of such an approach, three brick buildings were scanned with a terrestrial laser scanner. The data were processed with a recently proposed set of algorithms, and the reliability of the resulting solid models was evaluated by comparing finite-element results from auto-generated solid models versus those based on measured drawings. The proposed validation process considers overall response, as well as local behavior. The results show the importance of using both conventional values and project specific parameters. [ABSTRACT FROM AUTHOR]

Abstract: In tunneling, attempts at using remote sensing as a less expensive alternative to traditional surveying for creating computational models of masonry buildings for better damage prediction raise fundamental questions as to the necessary data quality, as there is a direct relationship between quality and acquisition costs. To understand the implications of such choices, 16 finite element models were devised to investigate the impact of window shape, brick orientation, window size, and the presence of lintels. Responses were considered with respect to gravity loads and excavation-induced subsidence. Permutations of three common window shapes were modeled as representative of Georgian brick structures. The base model was benchmarked against large-scale experimental work using non-linear analysis. This study proves that a few simple assumptions can be used in reducing the complexity of building façades for computation without generating major errors in structural response prediction. [Copyright &y& Elsevier]

Traditional documentation capabilities of laser scanning technology can be further exploited for urban modeling through the transformation of resulting point clouds into solid models compatible for computational analysis. This article introduces such a technique through the combination of an angle criterion and voxelization. As part of that, a k-nearest neighbor (kNN) searching algorithm is implemented using a predefined number of kNN points combined with a maximum radius of the neighborhood, something not previously implemented. From this sample, points are categorized as boundary or interior points based on an angle criterion. Façade features are determined based on underlying vertical and horizontal grid voxels of the feature boundaries by a grid clustering technique. The complete building model involving all full voxels is generated by employing the Flying Voxel method to relabel voxels that are inside openings or outside the façade as empty voxels. Experimental results on three different buildings, using four distinct sampling densities showed successful detection of all openings, reconstruction of all building façades, and automatic filling of all improper holes. The maximum nodal displacement divergence was 1.6% compared to manually generated meshes from measured drawings. This fully automated approach rivals processing times of other techniques with the distinct advantage of extracting more boundary points, especially in less dense data sets (<175 points/m2), which may enable its more rapid exploitation of aerial laser scanning data and ultimately preclude needing a priori knowledge. [ABSTRACT FROM AUTHOR]

Surveys and inventories of the built environment have improved the understanding of the state of existing heritage structures and historic districts and assisted in their preservation by thorough and consistent documentation. Unfortunately, full exploitation of these resources has been impeded by their static, non-interactive nature as printed documents (ie, reports or maps). This article presents recent attempts to improve access of such resources through their web-enablement. Specifically, issues of usability, relevance, contemporaneousness, and spatial integration are evaluated. These requirements are considered with respect to a new resource, Historic Ireland's Built Environment and Road Network Inventories Access (HIBERNIA). This integrated, extendable database and geographic information system (GIS) is featured as an example of how access to these surveys and inventories can be improved to form the basis for future developments to provide a more complete picture of heritage resources and enable innovative resource management strategies. [ABSTRACT FROM AUTHOR]

Use of microcrystalline waxes for the protection of ceramic art objects from seismic events is an inexpensive and relatively popular technique. Unfortunately, because of the high porosity of some ceramics and the fragility of their glazes and paints, the surface of many art objects may be vulnerable to damage from the microcrystalline wax. Thus, a conservative application approach is needed--applying only as much as is actually required for predicted levels of ground movement. Determining this quantity and verifying the best application technique (e.g., hot versus cold) has yet to be established. This paper presents the development of testing techniques to optimize the application of microcrystalline waxes; specifically, the pioneering of tensile and shear sample preparation. These procedures were applied to 70 tensile and 175 shear tests on paraffin wax, beeswax, and four microcrystalline waxes. Static testing methods demonstrated the clear superiority of certain products and average performance capabilities of up to 167 kN/m² in tension and 89 kN/m² in shear, under light loading. [ABSTRACT FROM AUTHOR]

Numerous localities have attempted to harness wind resources for electricity generation using roof-integrated wind turbines (RIWTs). Disappointingly, the monitored performance of RIWTs is typically only 5–11% of the designed capacity. Since direct wind measurement is expensive for micro-generation and simplified analytical methods are often insufficiently precise for complex geometries, poor outcomes are not surprising. To combat this, the current study explores the extent to which this deficit is due to poor RIWT placement in the absence of precise wind power information for installation sites and how this may be countered with terrestrial laser scanning-based models for complex structures. This is demonstrated with a cluster of complex suburban buildings with ground elevation changes of up to 4.2 m. Those data were used to populate a computational fluid dynamic model for detailed wind flow field simulation using a Navier–Stokes solver, ANSYS CFX. This approach demonstrated that wind power ranged from 0 to 100% of the capacity factor across the main study rooftop, representing the difference between cost recovery of a €16,500 RIWT in less than 1.5 years and a financially non-viable installation. This study provides a partial explanation for the disappointing results of RIWT installation, as well as a methodology to optimize RIWT placement to avoid non-viable installations and improve cost recovery period predictions. [ABSTRACT FROM AUTHOR]

• SCDA insertion into unit masonry walls of new and historic bricks and mortar. • Type N mortar exhibited slower but significantly more and wider cracking than lime only mortar. • Partial demolition, though not selective unit removal, was achieved for the first time in masonry walls. • Demonstrated viability of SCDAs for partial demolition of full-scale unit masonry. A soundless chemical demolition agent was applied for selective demolition to unit masonry [2 full-scale concrete brick walls in Type N mortar and 2 wallettes in lime mortar – 1 historic brick and 1 concrete brick]. Typically, cracking began shortly after 9 h and ultimately produced an average crack length of 418 mm per hole and an average maximum 5.22 mm crack width. Samples in Type-N mortar exhibited slower but significantly more cracks and wider cracking. Ninety-three percent of cracking occurred within 4 days. No masonry units were damaged and partial demolition was successful, although selective unit removal was not due to confinement. [ABSTRACT FROM AUTHOR]

Background: Conceptual models are an essential phase in software design, but they can create confusion and reduced performance for students in Database Design courses. Objective: A novel Relational Data Model Validation Tool (MVTool) was developed and tested to determine (1) if students who use MVTool perform better than those who do not, and (2) if design skills improve after using MVTool. Method: After a pre-test of database design skills, 68 students were divided into matched-pair control and experimental groups. All completed a database design task, with the experimental group having access to MVTool and the control group having no access to the tool. Findings: Notable improvements in specific design skills could be consistently detected in students after the introduction of the tool. Implications: Validation tools such as MVTool may help students to understand modeling languages and conventions used in database design, thereby improving their skill development and course outcomes. [ABSTRACT FROM AUTHOR]

This paper explores the problem of circle fitting for incomplete (partial arc) laser scanning point cloud data in the presence of outliers. In mobile laser scanning, data are commonly incomplete because of the orientation of the scanning unit to the surveying objects and the limited street-based positions. Also, multiple structures in the built environment often produce clustered outliers. To address these problems, this paper combines robust Principal Component Analysis (PCA) and robust regression with an efficient algebraic circle fitting method to develop two algorithms for circle fitting. Experimental efforts show that the proposed algorithms are statistically robust and can tolerate a high-percentage (exceeding 44%) of clustered outliers with insignificant error levels, while still achieving better shape recognition compared to existing competitive methods. For example, for a simulation of 1000 quarter circle datasets including 20% clustered outliers, RANSAC estimated the circle radius with a Mean Squared Error (MSE) of 172.10, whereas the proposed algorithms fit circles with an MSE of less than 0.42. The algorithms have potential in many areas including building information modeling, particle tracking, product quality control, arboreal assessment, and road asset monitoring. [ABSTRACT FROM AUTHOR]

Municipal and industrial wastewater treatment plants produce large amounts of sludge containing high levels of organic, chemical, and microbial pollutants. Unless stabilized completely and discharged safely, they may become potential pollution sources threatening soil and water bodies. This study investigated H2O2 oxidation and electrocoagulation as pretreatments to improve stabilization of an urban sludge. The H2O2 oxidation was optimized with respect to H2O2 dosage and initial sludge pH-H2O2. Batch electrocoagulation experiments were conducted using aluminum, iron, and zinc electrodes to investigate the effect of treatment period, current density, and pH. The effectiveness was compared in terms of solubilization of sludge, disintegration degree, and reduction of total solids. Sludge settling velocity after disintegration by both H2O2 oxidation and electrocoagulation were measured with respect to the operating conditions. The obtained results indicated that the high rate of sludge disintegration (63.3%) was obtained with aluminum electrodes, which has lower operating costs than iron and zinc electrodes. The H2O2 oxidation reached a maximum disintegration degree of 50%. Additionally, with aluminum and iron electrodes, sludge settleability was enhanced with both H2O2 oxidation and electrocoagulation. [ABSTRACT FROM AUTHOR]

Algerian's municipal sewage treatment plants generate around 10 6 m 3 of sewage sludge annually. Recently, rapid expansion of wastewater treatment plants without equal attention to the treatment of the produced sludge has generated increasing concerns. While the sludge is usually incinerated or used as an agricultural fertilizer and may contain numerous nutrients, there may also be harmful substances that complicate sludge management. Hence the removal of pollutants from the sludge is necessary before further usage. This paper discusses the characteristics of potable water treatment sludge containing a high aluminum content. Furthermore, an electrokinetic treatment is proposed to remove aluminum from this sludge by varying the type of solution contained in the cathode compartment and modifying the treatment time to optimize the efficiency of the process. Successful results were achieved where 60% of aluminum was collected on the cathode side with a consumed energy around of 1000–2000 kWh kg −1 of sludge weight. [ABSTRACT FROM AUTHOR]

This paper introduces a novel, region-growing algorithm for the fast surface patch segmentation of three-dimensional point clouds of urban environments. The proposed algorithm is composed of two stages based on a coarse-to-fine concept. First, a region-growing step is performed on an octree-based voxelized representation of the input point cloud to extract major (coarse) segments. The output is then passed through a refinement process. As part of this, there are two competing factors related to voxel size selection. To balance the constraints, an adaptive octree is created in two stages. Empirical studies on real terrestrial and airborne laser scanning data for complex buildings and an urban setting show the proposed approach to be at least an order of magnitude faster when compared to a conventional region growing method and able to incorporate semantic-based feature criteria, while achieving precision, recall, and fitness scores of at least 75% and as much as 95%. [ABSTRACT FROM AUTHOR]

Abstract: A large proportion of today''s digital datasets have a spatial component. The effective storage and management of which poses particular challenges, especially with light detection and ranging (LiDAR), where datasets of even small geographic areas may contain several hundred million points. While in the last decade 2.5-dimensional data were prevalent, true 3-dimensional data are increasingly commonplace via LiDAR. They have gained particular popularity for urban applications including generation of city-scale maps, baseline data disaster management, and utility planning. Additionally, LiDAR is commonly used for flood plane identification, coastal-erosion tracking, and forest biomass mapping. Despite growing data availability, current spatial information systems do not provide suitable full support for the data''s true 3D nature. Consequently, one system is needed to store the data and another for its processing, thereby necessitating format transformations. The work presented herein aims at a more cost-effective way for managing 3D LiDAR data that allows for storage and manipulation within a single system by enabling a new index within existing spatial database management technology. Implementation of an octree index for 3D LiDAR data atop Oracle Spatial 11g is presented, along with an evaluation showing up to an eight-fold improvement compared to the native Oracle R-tree index. [Copyright &y& Elsevier]

The dynamic analysis of contact problems is related to great mathematical difficulties and, thus, unsurprisingly has to date not been solved completely. In this work, a semi-analytical method is proposed to evaluate some integrals of Green's function used in the dynamic analysis of a rectangular plate resting on the surface of an elastic foundation of inertial properties (Lamb's model). The great challenge herein is overcoming the singularity present in the study of Green's function related to this problem. The proposed solution involves the discretization of the studied system (a rectangular plate resting on the surface of an elastic foundation of inertial properties), which leads to a numerical solution in matrix form. All the terms of the matrix are doubly indexed, and the singularity is present in the terms having the same indices. Therefore, special efforts are made to calculate the terms of the matrix having the same indices, in order to eliminate the singularity. This requires solving the integrals of the terms of the matrix with the same indices analytically and the integrals of the terms of the matrix of different indices by numerical methods. Finally, this study of Green's function is used in the dynamic analysis of the above-defined system and was successfully accomplished with a semi-analytical method leading to determinate values of the Eigen-frequencies and the Eigen-shapes of the plate. [ABSTRACT FROM AUTHOR]

In recent years, advanced manufacturing techniques, such as high-definition plasma, water jet, and laser cutting, have opened up an opportunity to create a new class of steel connections that rely on intermeshed (i.e. interlocked) components. The main advantage of this type of connection is that they do not require either welding or bolting, which allows faster construction. Although the interest in intermeshed connections has increased in recent years, the mechanical behavior of these connections has not been fully understood. This paper presents a numerical study on the ultimate load capacity failure modes of intermeshed connections under mixed-mode loading. The experimental behavior of the connection components is also investigated through a series of tests. The study considers a recently developed intermeshed connection for beams and columns. The numerical simulations were performed by using a commercially available 3D finite element software package. By considering different types of mixed mode loading, interaction diagrams of axial, shear, and moment capacities of the intermeshed connection were obtained. The results indicated that there exists an intricate interaction among axial, shear, and moment capacities, which arises from the intermeshed configuration of the flanges and web. For each interaction diagram, the corresponding failure mechanism was analyzed. The simulated interaction between axial, shear, and moment capacities were further compared with the provision of the current design codes. While the intermeshed connection studied here showed promise for gravity loading, further study is needed to ensure alignment of the flanges so as to avoid axial and/or flexural failures. • The intermeshed steel connection exhibits excellent shear resistance. • Axial and flexural behavior are affected by the alignment of the intermeshed flanges. • The presence of shear has a significant influence on axial and moment capacities. • P-M-V interactions in existing codes are not applicable to the intermeshed connection. • This connection could serve in gravity frames if flange alignment could be maintained. [ABSTRACT FROM AUTHOR]

Airborne Laser Scanning (ALS) was introduced to provide rapid, high resolution scans of landforms for computational processing. More recently, ALS has been adapted for scanning urban areas. The greater complexity of urban scenes necessitates the development of novel methods to exploit urban ALS to best advantage. This paper presents occlusion images: a novel technique that exploits the geometric complexity of the urban environment to improve visualisation of small details for better feature recognition. The algorithm is based on an inversion of traditional occlusion techniques. [ABSTRACT FROM AUTHOR]

• Advanced cutting techniques could help eliminate welding or bolting in steel connections. • Abaqus can accurately simulate the global and local behavior of the intermeshed connection. • The intermeshed connection transfers loads through interlocking pieces. • The modified design procedure assures a practical margin of overstrength in the connection. • In the redesigned specimens, most of the damage occurs in the connecting parts as planned. The aim of the present study is to develop insights into the structural performance of a recently developed 'intermeshed' steel connection, which transfers loads mainly through direct contact rather than by welds or bolts. This investigation was conducted through a step-by-step state assessment of the intermeshed connection subjected to multiple scenarios of gravity loading and by use of a nonlinear finite element platform. Implementation of the intermeshed connection would cause a discontinuity in the beam, so this paper addresses concerns regarding the load-transfer mechanisms and failure modes for these connections. The finite element simulations were performed in Abaqus, which is capable of handling material and geometrical nonlinearity, as well as the contact between individual surfaces. In order to verify the accuracy of these simulations, the numerical results were compared with experimental data from four physical tests. Finally, some important factors of influence such as connection segments sizes, lateral constraint, support conditions, and failure modes were also investigated through numerical analysis. The results of finite element analysis on different prototypes of steel intermeshed connection showed that the specimens with this connection provided sufficient ductility and resistance to meet design requirements. [ABSTRACT FROM AUTHOR]

Advanced manufacturing techniques, such as plasma, waterjet, and laser can facilitate field assembly and disassembly of steel structural components, and therefore potentially transform how steel structures are designed and constructed. These techniques have opened up an opportunity to create a new class of steel connections that rely on intermeshed (i.e. interlocked) components in lieu of traditional connectors such as weld and bolt. This paper presents an experimental investigation on the mechanics of such intermeshed steel connections manufactured by high-definition plasma and waterjet cutting. Four full-scale specimens with an intermeshed connection were designed to resist gravity loading in steel frames. The experimental testing program focused on the behavior of intermeshed connections under vertical loads including pure flexural and combined flexural-shear loading. Both global load-deflection response and local deformation were measured to provide insights into the complex load transfer mechanisms. The experiments demonstrated ample load carrying capacity, approaching the beam plastic moment, and ample ductility, approaching a deflection over span length ratio of 1/60 to 1/40, through the interaction of individual components. Analysis of the test data also raises important questions that must be addressed for the practical design of these connections. • Advanced cutting techniques could help eliminate welding or bolting in steel connections. • The intermeshed connection transfers loads through interlocking pieces. • Waterjet and plasma cutting could meet the precision of the intermeshed connection. • The intermeshed steel connection exhibits ample load carrying capacity and ductility. • The angles and shear plates contribute in both moment and shear load transfer. [ABSTRACT FROM AUTHOR]

Current processes that create Building Energy Performance Simulation (BEPS) models are time consuming and costly, primarily due to the extensive manual inputs required for model population. In particular, generation of geometric inputs for existing building models requires significant manual intervention due to the absence, or outdated nature of available data or digital measurements. Additionally, solutions based on Building Information Modelling (BIM) also require high quality and precise geometrically-based models, which are not typically available for existing buildings. As such, this work introduces a semi-automated BEPS input solution for existing building exteriors that can be integrated with other related technologies (such as BIM or CityGML) and deployed across an entire building stock. Within the overarching approach, a novel sub-process automatically transforms a point cloud obtained from a terrestrial laser scanner into a representation of a building's exterior façade geometry as input data for a BEPS engine. Semantic enrichment is performed manually. This novel solution extends two existing approaches: (1) an angle criterion in boundary detection and (2) a voxelisation representation to improve performance. The use of laser scanning data reduces temporal costs and improves input accuracy for BEPS model generation of existing buildings. The approach is tested herein on two example cases. Vertical and horizontal accuracies of 1% and 7% were generated, respectively, when compared against independently produced, measured drawings. The approach showed variation in accuracy of model generation, particularly for upper floors of the test case buildings. However, the energy impacts resulting from these variations represented less than 1% of the energy consumption for both cases. • Introduces a semi-automated BEPS input solution for existing, building exteriors • Processes a point cloud to create a buildingŠs geometry as input data for BEPS • Extends angle criterion in boundary detection and voxelisation representation • Laser scanning reduces time and improves input accuracy for BEPS models. • Validated on two cases: vertical and horizontal accuracy of 1 [ABSTRACT FROM AUTHOR]

Street view imagery databases such as Google Street View, Mapillary, and Karta View provide great spatial and temporal coverage for many cities globally. Those data, when coupled with appropriate computer vision algorithms, can provide an effective means to analyse aspects of the urban environment at scale. As an effort to enhance current practices in urban flood risk assessment, this project investigates a potential use of street view imagery data to identify building features that indicate buildings' vulnerability to flooding (e.g., basements and semi-basements). In particular, this paper discusses (1) building features indicating the presence of basement structures, (2) available imagery data sources capturing those features, and (3) computer vision algorithms capable of automatically detecting the features of interest. The paper also reviews existing methods for reconstructing geometry representations of the extracted features from images and potential approaches to account for data quality issues. Preliminary experiments were conducted, which confirmed the usability of the freely available Mapillary images for detecting basement railings as an example type of basement features, as well as geolocating the features., (© The Author(s) 2023.)

New York City (NYC) was deeply impacted by COVID-19 in spring 2020, with thousands of new cases daily. However, the pandemic's effects were not evenly distributed across the city, and the specific contributors have not yet been systematically considered. To help investigate that topic, this study analyzed the interaction of people with neighborhood businesses and other points of interest (POIs) in parts of three NYC neighborhoods in the spring of 2020 during the peak of the first COVID-19 wave through anonymized cellphone data and direct the observation of 1313 individuals leaving healthcare facilities. This study considered social vulnerability index (SVI) levels, population density, and POI visit behaviors from both cellphone data and firsthand observations of behavior around select NYC health facilities in different boroughs as various proxies. By considering equivalent businesses or groups of businesses by neighborhood, POI visits better aligned with COVID-19 infection levels than SVI. If tracking POI visit levels proves a reliable direct or relative proxy for disease transmission when checked against larger datasets, this method could be critical in both predictions of future outbreaks and the setting of customer density limits.