1,721,248 research outputs found
A physics-based simulation approach for cooperative erection activities
No full textCooperative erection activities are critical to projects which involve the erection of heavy loads or theinstallation of special equipment. Detailed simulation on computer prior to construction can identifyconstructability problems, and subsequently avoided during actual erections. This paper describes anintegrated approach for simulating the detailed motions of cranes. This research develops a physics-basedmodel that follows the principle of closed-form forward kinematics and constraint-based dynamics topresent the dual-crane mechanism mathematically — a non-trivial task. This model can be used to analyzethe inputs from the users (i.e. virtual crane operators) and simultaneously compute the cables sway andreaction of collisions. We also implemented the model on computer and developed a simulation system,Erection Director, to render realistic cooperative erection activities. A demonstration of simulating two-cranelift has been built and three performance tests including a small building (840 elements), a medium building(1937 elements) and a large building (2682 elements) validate the feasibility of the proposed approach. Thetest results indicate that Erection Director can support real-time and physics-based visualization ofcooperative erections
Gearing up academics for collaborative Building Information Modelling (BIM) education
No full textBuilding information modelling (BIM) radically changes the practices in architecture, engineering and construction (AEC) and creates new job opportunities. Many governments, such as the United Kingdom, have made BIM a mandatory requirement. This substantially drives the demand for a BIM-literate workforce. Universities are facing the challenge to incorporate BIM into their curricula and produce “BIM ready” graduates to meet the needs of the industry. Like other universities, Queensland University of Technology (QUT) is at the heart of this change and aspires to develop collaborative BIM education across AEC. Previous BIM education studies identify that inadequate BIM awareness of AEC academics is one of the challenges for developing a BIM curriculum and there is a dearth in the learning and teaching support for academics on BIM education. Equipping the AEC academics for a more BIM focused curriculum is all the while more important. This paper aims to leverage knowledge drawn from a Learning & Teaching project currently undertaken at QUT. Its specific objectives are to: 1) review the existing learning and teaching initiatives on BIM education; and 2) briefly describe the learning and teaching activities on collaborative BIM education at QUT. Significance of the paper lies on revealing the importance of building up the capacity of AEC academics for collaborative BIM education. The paper contributes to sparking the interests in better equipping AEC academics to understand what curriculum changes would assist in BIM uptake within the relevant courses to provide context for changes in units; and how the use of BIM can improve the understanding by students of the large amounts of professional knowledge they need to function effectively as graduates
Physics-Based Simulation of Detailed Erection Activities of Construction Cranes
No full text在現代營建工程中，工程吊車往往扮演舉足輕重的地位，以鋼構建築工程為例，約有25%之工程費用與吊車及其作業直接相關，故吊裝施作之效率為營建工程探討的重要課題。現今電腦輔助軟體藉由合適的工程吊車模擬，提供數值化及視覺化的資訊，期能經由先期吊裝模擬獲取完善之施工資訊，避免實際施工上可能發生的問題。本研究之目的即在於整合物理模擬技術，進行吊裝作業的詳細模擬，提高擬真性與減少和真實施作過程中的差異。
研究中針對工程吊車之物理特性發展數值化之吊車模型，依據吊車各部件活動的性質，將此模型分為兩部分：可操作性機具模型(Manipulation model)與非操作性懸吊模型(Suspension model)，分別依據前序運動學(closed-form forward kinematics)理論與約束剛體動力學(constraint-based rigid body dynamics)理論來建構，前序運動學定義各關節連結的從屬結構及座標轉換運算，求得機具於虛擬環境中的幾何位置，如此配合操作員輸入的操作指令，便能動態地反映虛擬機具的動作行為；而約束剛體動力學描述關節的運動限制，於運動方程式中求取受限制力作用下的位置與方位資訊，表現出類似真實世界的物理行為。此機具模型包含輪、機身、吊臂等剛體部分；而懸吊模型則包含吊索與吊鉤等動態部分，前者藉由判明位置的改變量並視為外在受力來影響後者的運動，如此便能做出如吊索甩動的物理行為。
本研究針對吊裝作業模擬發展出一視覺化平台：Erection Director。此系統提供使用者自訂的彈性介面，並將上述之吊車模型實作於虛擬環境中，藉由即時的繪圖及物理引擎計算，模擬各種吊裝情境。其中特別將柱結構之吊裝作業與雙吊車協同起吊作業兩項目於平台上實作，經比對實際工程現場的吊裝方式，此兩項模擬皆能達到擬真的吊裝過程。
本研究建立實際吊裝作業之模擬技術，未來可延伸應用於吊裝計畫的完整模擬，提供規劃施工路徑的可行性檢測，讓計畫本身具有更高的可信度，亦可與現今自動化技術相輔相成，為吊裝作業提供更為完善與準確的解決方案。Construction cranes are one of the most important types of equipment in construction projects, which are essential to transport structural elements and building materials. Efficiency of crane operations may significantly influence the schedule and the cost of a construction project. One of the major problems is that the erection activities are very difficult to be simulated in details. Therefore, this research integrates physics-based simulation for generating practical erection activities that are relevant to complex situations of construction.
The major effort in this research is to develop a numerical model to simulate cranes to realize the physics-based simulations. The numerical model of crane can be generally divided into two sub-models: the manipulation model and the suspension model. The manipulation model was constructed by following the principle of closed-form forward kinematics. It facilitates the computation of the position and orientation of an articulated crane components with respect to the global coordinate by multiplying transformation matrices. The suspension model was formulated by following the principle of constraint-based rigid body dynamics. By describing the joint relationships between connected rigid bodies precisely, the realistic simulation of suspension objects can be obtained.
A prototype system, named Erection Director, was implemented to integrate the manipulation model and suspension model developed in the research. Because the physics-based simulation is available, the computer system allows users to simulate and realistically visualize the erection activities before these activities are performed in the field. Two example cases, one is column erection and the other is dual-crane cooperative erection, were presented to demonstrate the feasibility of these numerical models.
A physics-based environment for simulating detailed erection activities was built in this research. Because the high-fidelity visualizations can be generated in the virtual environment, the engineers can plan the erection activities precisely before the construction. This may increase construction speed, safety, and return on investment (ROI).誌謝 I
ABSTRACT III
摘要 V
TABLE OF CONTENT VII
LIST OF FIGURES IX
LIST OF TABLES XI
1 INTRODUCTION 1
1.1 Motivation and Background 1
1.2 Objective and Scope 3
1.3 Organization of Thesis 3
2 THE ERECTION ACTIVITIES 5
2.1 Related Research 5
2.2 Field Observation 9
3 CRANE MODELING 15
3.1 Physics-Based Simulation Methods 15
3.2 Physics-Based Crane Model 18
3.3 Manipulation Model 19
3.4 Suspension Model 28
3.5 Summary 34
4 SIMULATION OF ERECTION ACTIVITIES 37
4.1 Development of Erection Director 37
4.2 Example Case: Column Erection 45
4.3 Example case: Dual-Crane Cooperative Erection 50
4.4 Summary 53
5 CONCLUSION AND FUTURE WORK 55
5.1 Summary 55
5.2 Contribution of this Research 57
5.3 Future Work 58
REFERENCES 5
Transnational adaptation model for facilitating technology and expertise mobilisation in Gulf AEC organisations
Full text linkThe fragmented nature of the Architecture, Engineering, and Construction (AEC) industry is well recognised, the main issues of which relate ostensibly to failures in communication, process, productivity and interoperability. These failures have contributed to an increased proliferation of adversarial relationships between the different parties involved in projects, the result of which has deleteriously affected the product [project]. Challenges include a wide range of issues, from the veracity of design information within the project lifecycle, through to supply chain communication. These are global issues. For example, in the Gulf States, the nature and complexity of AEC projects have changed significantly due to increased globalisation and the emergence of enmeshed transnational practices. This has created an overwhelming reliance on the mobilisation and transfer of technology and expertise of professional expatriates, which has influenced the approach taken to traditional design and construction business models, including staff roles and procedures. New knowledge and ways of working have been expressed as a means of supporting future projects in the Gulf States. Acknowledging this, there is a need to capture and codify domain-specific expertise. This paper discusses the need to purposefully enhance Qatar’s AEC industry by fostering a smooth transition from its current position, into a more sustainable state that is capable of being replicated. The philosophical underpinnings of this paper take into account disparate socio-cultural, environmental and economic impacts of change, in terms of business models, technology, innovation, labour market needs, local laws/bylaws, and legislation. A theoretical growth model is presented for discussion. This builds on the experience of the UK (in particular) in terms of facilitating the mobility and penetration of technology/expertise/change in the AEC sectors. This paper presents a series of recommendations needed to develop a Pervasive Transnational Adaptation model for Qatar and the Gulf States, covering such issues as: ICT adoption, agile project management, technology-transfer, innovation, offsite construction, Public Private Partnerships, capacity building, and international strategic alliances
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
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