Multiple handheld three-dimensional (3D) systems are available on the market, but data regarding their use in detecting small volumes are limited. The aim of this study was to compare different ...portable 3D technologies in detecting small volumetric enhancement on a mannequin model and a series of patients.
Five portable 3D systems (Artec Eva, Crisalix, Go!Scan, LifeViz Mini, and Vectra H1) were tested in a controlled environment with standardised volumes and in a clinical setting with patients undergoing small volume fat grafting to face, vulva, and hand. Accuracy was assessed with absolute and relative technical error measurement (TEM and rTEM); precision with intra- and inter-observer reliability (rp and ICC); and usability in clinical practice with the following parameters: portability, suitability of use in operating theatre/clinic, ease of use of hardware and software, speed of capture, image quality, patient comfort, and cost. All tested devices presented overall good accuracy in detecting small volumetric changes ranging from 0.5 to 4 cc. Structured-light laser scanners (Artec Eva and Go!Scan) showed high accuracy, but their use in clinical practice was limited by longer capture time, multiple wiring, and complex software for analysis. Crisalix was considered the most user-friendly, less bothering for patients, and truly portable, but its use was limited to the face because the software does not include vulva and hand. Three-dimensional technologies exploiting the principle of passive stereophotogrammetry such as LifeViz Mini and Vectra H1 were the most versatile for assessing accurately multiple body areas, representing overall the best long-term value for money.
Therefore, 3D portable technology is a non-invasive, accurate, and reproducible method to assess the volumetric outcome after facial, vulval, and hand injectables. The choice of the 3D system should be based on the clinical need and resources available.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Two-dimensional laser scan sensors stand out as the preferred choice for robot mapping applications. However, these sensors have a significant drawback. Encountering objects with varying shapes at ...different heights, such as tables, poses challenges for these sensors due to their limited detection capability resulting from their dimensionality. This limitation increases the risk of potential collisions. Additionally, there are multiple polished materials that generate noise due to reflection. In order to have a robust occupancy grid map representation, these problems must be addressed. This paper proposes the usage of a 3D laser scan sensor to generate a 2D occupancy grid map that incorporates the complete geometry of objects and effectively filters out noise from reflective materials like glass. The main novelty of the method is that it takes advantage of all the available 3D data to avoid any information loss about objects' shapes. Additionally, a new approach for filtering reflection noise based on the analysis of indoor structural elements is proposed. Both approaches are merged for the creation of a robust indoor representation that allows to safely navigate the environment. Finally, a recursive Bayesian filter is applied for merging data, so noise due to dynamic elements that appeared during data collection is also filtered. Experimental evaluations in indoor environments with diverse objects and reflective surfaces, including dynamic elements like people, demonstrate the effectiveness of the proposed approach.
Pavement condition surveying is vital for pavement maintenance programs that ensure ride quality and traffic safety. This paper first introduces an automated pavement inspection system which uses a ...three-dimensional (3D) camera and a structured laser light to acquire dense transverse profiles of a pavement lane surface when it carries a moving vehicle. After the calibration, the 3D system can yield a depth resolution of 0.5 mm and a transverse resolution of 1.56 mm pixel−1 at 1.4 m camera height from the ground. The scanning rate of the camera can be set to its maximum at 5000 lines s−1, allowing the density of scanned profiles to vary with the vehicle's speed. The paper then illustrates the algorithms that utilize 3D information to detect pavement distress, such as transverse, longitudinal and alligator cracking, and presents the field tests on the system's repeatability when scanning a sample pavement in multiple runs at the same vehicle speed, at different vehicle speeds and under different weather conditions. The results show that this dedicated 3D system can capture accurate pavement images that detail surface distress, and obtain consistent crack measurements in repeated tests and under different driving and lighting conditions.
•DFOS is able to detect spatial variation of steel rebar corrosion to some extent.•Spatial variation of corrosion causes erroneous strain readings of DFOS.•Strain transfer coefficient decreases as ...corrosion-induced area loss increases.•Strain transfer coefficient increases when stress level in steel rebar increases.
Distributed fiber optic sensors (DFOSs) have become an effective tool for deformation and cracking monitoring in reinforced concrete structures due to their multiple sensing points. However, the monitoring accuracy is affected by the strain transfer efficiency between the monitored structural substrate and DFOS. This study experimentally investigates the effect of localized corrosion and stress level on the strain transfer efficiency between corroded steel rebars and DFOS. Steel rebars installed with DFOS were cast in a concrete slab and then subjected to accelerated corrosion tests up to ∼ 12.00% area loss. The residual cross-sectional area distribution of corroded steel rebars was determined based on 3D laser scan data. Tensile tests were conducted, during which the strain distribution of DFOS under different loading levels was recorded with an optical interrogator and then compared with theoretical values. Results show that corrosion does not directly affect the strain transfer efficiency between steel rebars and DFOS, but spatial variation of corrosion causes high strain gradients in steel rebars that result in erroneous strain readings. DFOSs are able to identify the location of big corrosion pits, but the strain transfer coefficient is less than 100% at locations with big corrosion pits while it is over 100% at nearby sections. The strain transfer coefficient increases with an increase in stress level in the elastic stage of steel rebars, while it decreases with an increase in area loss especially for sections with pitting corrosion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The current study presents a four-step methodological approach for the conservation and repair of a Middle Byzantine Era cistern. In the first stage of the study, the samples gathered from different ...parts of the ruin were subjected to physical and chemical analyzes. In the second stage, the material compositions were determined by evaluating the data obtained by the analyses. Then, the seismic performance level of the cistern was determined through linear, pushover, and kinematic limit analyses. With these analyses, story displacements, shear forces, and story drifts were determined and compared with the values set forth in the seismic code. In the last step, conservation and repair practices were performed considering the data obtained in the previous stages. Accordingly, a cultural asset belonging to the Middle Byzantine era was consolidated and repaired that would contribute to cultural tourism in the region. The current study is believed to make a valuable contribution to the literature and guide academics and designers since it presents all critical stages of a conservation and repair process for a buried ruined structure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•This paper presents a non-contact approach for a large-scale cable tension evaluation.•The presented non-contact approach is based on 3D laser scanning data.•An actual case study of the long-span ...roof cable of a big exhibition center in Thailand is performed to show the effectiveness of the presented approach.•The presented non-contact approach yields satisfactory results compared with a conventional method by measuring the cable’s natural frequency.
This study proposes a non-contact approach for tension evaluation of a large-scale cable-stayed roof. Three-dimensional (3D) laser scanning data based on a terrestrial laser scanner are utilized to explore the current cable configuration in 3D. Subsequent analysis of the exact current cable configuration indicates that the cable tension can be evaluated by minimizing the cable configuration error. The precise cable tension, which correlates with the actual cable configuration, is determined using nonlinear finite element analysis which is based on a model formulation that considers the effect of bending rigidity. The proposed method is verified by experimental studies. A case study is performed of the long-span roof cable of a large exhibition center in Thailand to demonstrate the effectiveness of this approach in comparison with the natural frequency measurement-based method. The results show that the proposed method is an alternative non-contact approach for evaluating cable tension with reasonable accuracy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In historical masonry buildings, the durability of materials used for the structural members can be impaired by climatic conditions and user interventions, and the building may lose its authenticity ...as a result of functional changes made over time. To restore structures to their original form, the historical changes that have been made over time are researched, and by identifying the original material characteristics it becomes possible to preserve the load-bearing members, thus prolonging their service life. This paper presents a detailed description of the restoration works, which were based on the original geometric and material properties, carried out on a historical masonry building that started out in life as a hospital building in the 1840s, but was later remodeled to become a military prison building and currently serves as the Faculty of Political Sciences of Istanbul University. The study is presented in three stages, namely: i. a research of the historical timeline of alterations of the examined building, ii. a field study, and iii. laboratory analyses. The historical research identifies the structural changes that the building has undergone since its construction, while the field study includes a three-dimensional laser scanning process and the taking of representative samples from different points of the building. In the laboratory stage, the gathered samples are subjected to chemical and mineralogical analyses. The mortar and plaster mixture ratios used in the construction were ascertained through physical and chemical tests to samples taken from the building, and subsequently, all non-original binder materials have been removed and the original mortar-plaster mixture ratios have applied. After a review of the data collected within the scope of this study, it was determined that the two reinforced concrete buildings to the north and south of the site, which were built later in the history of the investigated building, as well as the temporary partition walls to each story, should be removed. Furthermore, it is recommended that the modified facade and interior window forms, together with the blocked-off doorways, should be restored to their original state. The contribution this study makes to literature is based on its focus on a historical masonry building that has lost its original form over time, having been refunctioned for different purposes, that is to be restored back to its original form in terms of its geometric and material properties. The building itself is of particular interest, being the first on the historical peninsula of Istanbul to be constructed using industrial bricks during the Ottoman period. The proposed restoration project can be considered a novel, practical and appropriate approach to authentic restoration.
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BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
Although the number of marine accidents has gradually decreased, fatal ones continue to occur. To prevent huge losses of life, environment and property, there are sufficient laws, rules and ...regulations, which include many technical solutions. Notably, many solutions for damaged ships are suggested to prevent capsizing and sinking. However, many pioneering ideas for damaged ships remain at the conception level because of the lack of technical and economic feasibility. To have both technical and economic feasibility in the design process, in this study, a business-model-adopted design process has been considered. Using this design process, a new concept for buoyancy support systems is studied, which considers the technical and economic matters in the design process. In addition, a fixed fire-fighting system and 3d laser scan data basis 3-dimensional buoyancy support system are been studied. To convince the usability of the suggested concept, computational simulation was used at the abstract level. Because there can be thousands of damage scenarios for a ship, sampled catastrophic damage scenarios are used in the case study to confirm the possibility of the suggested concept of buoyancy support systems.
•For ship safety, new concept for buoyancy support system has proposed.•Proposed system focus on not only technical feasibility but also economic feasibility.•For inner ship installation, 3d laser scan data basis 3-dimensional buoyancy chamber has considered.•Fixed fire-fighting system also has considered for gas injection system.•The utility of the system has checked by computational ship flooding behavior simulation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
AbstractThis paper presents a process management framework for multisensory data fusion for the purpose of tracking the progress of construction activity. The developed framework facilitates the ...required type of data fusion at any given point in the construction progress, reliably and efficiently. Data are acquired from high-frequency automated technologies such as three-dimensional (3D) imaging and ultrawideband (UWB) positioning, in addition to foreman reports, schedule information, and other information sources. The results of validation through a detailed field implementation project show that the developed framework for fusing volumetric, positioning, and project control data can successfully address the challenges associated with fusing multisensory data by tracking activities rather than objects, a feature that offers superior capability, efficiency, and accuracy over the length of the project. Other contributions of this research include the development of fusion processes that are performed at higher levels of data fusion instead of traditional low-level fusion algorithms, thus supporting decision-making processes and a number of automated construction management applications, such as construction progress tracking, earned-value estimation, and schedule updating.
•It is investigated that the original status of the ruin from early Byzantine- and Ottoman-periods.•Macro and micro structure analyses are carried out with related to the specimens gathered from ...different locations of the ruined structure.•3D laser scan survey is performed on the historical masonry ruin.•The conservation and repair proposals are presented regarding the ruined structure.
Historical masonry structures that remained under the ground due to settlement have to be revealed and preserved because of their historical values. The study focuses on assessment of wall ruin from early Byzantine period and the arched vault ruin from Ottoman period. In this study, the properties and problems of the materials as mortars and woods were analyzed, which were gathered from the ruin structure – wall, vault, brick pipe and bonding wood. The study consists of the on-site examination, laboratory analyses and application proposals about the wall ruin from early Byzantine era and arched vault ruin from Ottoman era which were unearthed during the re-construction of education building. In the first stage of study, representative samples taken from different locations of the masonry ruin were exposed to chemical- and mineralogical-analyses, and the content of samples were determined. In the second stage, the data of analysis were assessed, then the conservation and repair proposals were submitted for implementing on the masonry ruin. By proposed materials for the conservation, it will not be occurred mechanical stresses due to the original and new repair mortar- and wood-materials have the similar physical and mechanical properties. Thus, this will lead to long and healthy life to the original materials of the ruin structure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
