1,721,165 research outputs found
Automatic Reconstruction of As-built BIM from Laser Scanned Data of Precast Concrete Elements for Dimensional Quality Assessment
No full textPrecast concrete elements are popularly used in the construction of buildings and infrastructures because they enable higher construction quality, less construction time, and less environmental impact. To ensure the performance of complete precast concrete systems, dimensional quality of individual precast concrete elements must be assessed before they are transported to the construction sites. However, the current quality assessment methods mainly rely on manual inspection with traditional measurement devices, which are inefficient and inaccurate. Besides, the quality assessment results are not well managed. To realize efficient and accurate quality assessment of precast concrete elements and to facilitate the management of quality assessment results, this study proposes a technique which can automatically reconstruct the as-built Building Information Models (BIM) from laser scan data of precast concrete elements for dimensional quality assessment. The proposed technique firstly performs a scan planning to determine the number of scans and the locations of scanners. Then, the preprocessing of scan data removes noisy data and registers multiple scans in a global coordinate system. Afterwards, the as-built geometries of the element are extracted from the registered scan data, and finally the as-built BIM is reconstructed. To validate the proposed technique, a scanning experiment was conducted on a small-scale test specimen. The experimental results demonstrate that the proposed technique can accurately and efficiently create asbuilt BIM of precast concrete elements
A web-based collaborative system framework for green building certification
No full textThe built environment is moving towards sustainable development and the number of green buildings increased worldwide in recent years. Green buildings are environmentally, socially and economically desirablehowever the certification of green buildings is often expensive and labor-intensive. The document preparation and review process for green building certification is iterative in nature and requires the collaboration of many project participants, certification organizations and third party engineering consultants. This paper aims at developing a system framework that can assist the green building certification process. Different certification standards have been studied and their scope and credit calculation were compared to understand the requirements of the system framework. Based on the study, the required features were designed as follows, (1) role-based access control, (2) document manager and related document discovery, (3) workflow manager, (4) credit manager, and (5) knowledge manager. The features of the system provide a collaborative environment and reduce repetitive works commonly occurring in manual processes. The features of the system framework are discussed and illustrated considering the Hong Kong BEAM Plus standard. This paper also describes how the system framework enhances collaboration in the certification process
라인 레이저 스캐너에 의한 DED 3D 프린팅 제조과정에서의 치수품질 평가
No full text학위논문(박사) - 한국과학기술원 : 건설및환경공학과, 2023.8,[vi, 115 p. :](3) there is a lack of real-time geometry monitoring and geometry estimation for depositions with sharp features, such as corners and intersections. Therefore, this research provides approaches to achieve online geometry quality assessment during the DED process using laser line scanner, including real-time geometry monitoring and real-time geometry estimation. In addition, this research put emphasis on geometry with sharp features which are often problematic and not well studied in previous literatures. The proposed online geometry assessment techniques could effectively facilitate DED to achieve zero-defect manufacturing and assist its adoption in various fields including the construction industry.(2) real-time geometry estimation that can establish explicit relationship between process parameters and geometry attributes is not well studied, which impedes the development of geometry quality controlMetallic materials are widely adopted in the construction industry. While traditional manufacturing techniques such as hot-rolling, cold-forming and extrusion often leads to prismatic structural components, adopting metal additive manufacturing (AM) technologies, such as Directed Energy Deposition (DED), will allow greater flexibility in the geometry of construction components. However, geometry inconsistency in DED is one of the main problems that hinders its application in construction industry. Lack of timely geometry assessment during DED process results in dimensional errors and defects of final products. Therefore, this research proposes to develop and integrate advanced process monitoring techniques into a DED system with a goal of online geometry quality assessment in support of quality assurance and process certification. To achieve geometry quality control, geometry quality assessment including geometry monitoring and geometry estimation are needed. According to existing literature review about geometry quality assessment during DED process, the research gaps are identified: (1) there is a lack of online real-time geometry monitoring technique to inspect each deposited track profile, which requires the integration of 3D geometry monitoring system with DED system한국과학기술원 :건설및환경공학과
A Distributed Twin System for Managing Asset-process Interactions in Highway Infrastructure Systems
No full textHighway agencies face challenges managing scattered asset data across maintenance processes and information systems, obstructing efficient retrieval of dynamic cross-system road information for timely interventions. This paper presents a Digital Twin (DT)-based data federation framework to effectively manage fragmented systems and dispersed data for highway infrastructure operation and maintenance. The framework middleware can decompose users’ queries and requests from different subsystems based on a metadata database and a distributed system architecture. The connected data ecosystem enables dynamic communication between different asset systems, ensuring efficient maintenance planning and process coordination between different users and teams. The presented framework is demonstrated based on datasets and synthesised systems conforming to asset management practices adopted by United Kingdom (UK) National Highways
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
