Amir H. Behzadan

Visualization of construction graphics in outdoor augmented reality

This paper describes research that investigates the application of augmented reality (AR) in 3D animation of simulated construction operations. The objective is an AR-based platform that can be used together with corresponding equipment (HMD, GPS receiver, and a portable computer) to generate a mixed view of the real world and superimposed virtual simulation objects in an outdoor environment. The characteristic that distinguishes the presented work from indoor AR applications is the capability to produce real time updated output as the user moves around while applying minimum constraints over the users position and orientation. The ability to operate independently of environmental factors (e.g. lighting conditions and terrain variations) makes the described framework a powerful tool for outdoor AR applications. This paper presents initial results and an AR platform prototype (UM-AR-GPS-ROVER) that is able to place 3D graphical objects at any desired location in outdoor augmented space.

General-purpose modular hardware and software framework for mobile outdoor augmented reality applications in engineering

This paper presents a reusable, general-purpose, mobile augmented reality (AR) framework developed to address the critical and repetitive challenges specific to visualization in outdoor AR. In all engineering applications of AR developed thus far, basic functionality that supports accurate user registration, maximizes the range of user motion, and enables data input and output has had to be repeatedly re-implemented. This is primarily due to the fact that designed methods have been traditionally custom created for their respective applications and are not generic enough to be readily shared and reused by others. The objective of this research was to remedy this situation by designing and implementing a reusable and pluggable hardware and software framework that can be used in any AR application without the need to re-implement low-level communication interfaces with selected hardware. The underlying methods of hardware communication as well as the object-oriented design (OOD) of the reusable interface are presented. Details on the validation of framework reusability and pluggability are also described.

An integrated data collection and analysis framework for remote monitoring and planning of construction operations

Recent advances in data collection and operations analysis techniques have facilitated the process of designing, analyzing, planning, and controlling of engineering processes. Mathematical tools such as graphical models, scheduling techniques, operations research, and simulation have enabled engineers to create models that represent activities, resources, and the environment under which a project is taking place. Traditionally, most simulation paradigms use static or historical data to create computer interpretable representations of real engineering systems. The suitability of this approach for modeling construction operations, however, has always been a challenge since most construction projects are unique in nature as every project is different in design, specifications, methods, and standards. Due to the dynamic nature and complexity of most construction operations, there is a significant need for a methodology that combines the capabilities of traditional modeling of engineering systems and real time field data collection. This paper presents the requirements and applicability of a data-driven modeling framework capable of collecting and manipulating real time field data from construction equipment, creating dynamic 3D visualizations of ongoing engineering activities, and updating the contents of a discrete event simulation model representing the real engineering system. The developed framework can be adopted for use by project decision-makers for short-term project planning and control since the resulting simulation and visualization are completely based on the latest status of project entities.

Collaborative visualization of engineering processes using tabletop augmented reality

3D computer visualization has emerged as an advanced problem-solving tool for engineering education and practice. For example in civil engineering, the integration of 3D/4D CAD models in the construction process helps to minimize the misinterpretation of the spatial, temporal, and logical aspects of construction planning information. Yet despite the advances made in visualization, the lack of collaborative problem-solving abilities leaves outstanding challenges that need to be addressed before 3D visualization can become widely accepted in the classroom and in professional practice. The ability to smoothly and naturally interact in a shared workspace characterizes a collaborative learning process. This paper introduces tabletop Augmented Reality to accommodate the need to collaboratively visualize computer-generated models. A new software program named ARVita is developed to validate this idea, where multiple users wearing Head-Mounted Displays and sitting around a table can all observe and interact with dynamic visual simulations of engineering processes. The applications of collaborative visualization using Augmented Reality are reviewed, the technical implementation is covered, and the programs underlying tracking libraries are presented.

Knowledge-Based Simulation Modeling of Construction Fleet Operations Using Multimodal-Process Data Mining

AbstractIn order to develop a realistic simulation model, it is critical to provide the model with factual input data based on the interactions and events that take place between real entities. However, the existing trend in simulation of construction fleet activities is based on estimating input parameters such as activity durations using expert judgments and assumptions. Not only may such estimations not be precise, but project dynamics can influence model parameters beyond expectation. Therefore, the simulation model may not be a proper and reliable representation of the real engineering system. In order to alleviate these issues and improve the current practice of construction simulation, a thorough approach is needed that enables the integration of field data into simulation modeling and systematic refinement of the resulting models. This paper describes the latest efforts by authors to design and test a novel methodology for multimodal-process data capturing, fusion, and mining that provides a solid...

Construction equipment activity recognition for simulation input modeling using mobile sensors and machine learning classifiers

Although activity recognition is an emerging general area of research in computer science, its potential in construction engineering and management (CEM) domain has not yet been fully investigated. Due to the complex and dynamic nature of many construction and infrastructure projects, the ability to detect and classify key activities performed in the field by various equipment and human crew can improve the quality and reliability of project decision-making and control. In particular to simulation modeling, process-level knowledge obtained as a result of activity recognition can help verify and update the input parameters of simulation models. Such input parameters include but are not limited to activity durations and precedence, resource flows, and site layout. The goal of this research is to investigate the prospect of using built-in smartphone sensors as ubiquitous multi-modal data collection and transmission nodes in order to detect detailed construction equipment activities which can ultimately contribute to the process of simulation input modeling. A case study of front-end loader activity recognition is presented to describe the methodology for action recognition and evaluate the performance of the developed system. In the designed methodology, certain key features are extracted from the collected data using accelerometer and gyroscope sensors, and a subset of the extracted features is used to train supervised machine learning classifiers. In doing so, several important technical details such as selection of discriminating features to extract, sensitivity analysis of data segmentation window size, and choice of the classifier to be trained are investigated. It is shown that the choice of the level of detail (LoD) in describing equipment actions (classes) is an important factor with major impact on the classification performance. Results also indicate that although decreasing the number of classes generally improves the classification output, considering other factors such as actions to be combined as a single activity, methodologies to extract knowledge from classified activities, computational efficiency, and end use of the classification process may as well influence ones decision in selecting an optimal LoD in describing equipment activities (classes).

Factors Influencing Unsafe Behaviors and Accidents on Construction Sites: A Review

Objective. Construction is a hazardous occupation due to the unique nature of activities involved and the repetitiveness of several field behaviors. The aim of this methodological and theoretical review is to explore the empirical factors influencing unsafe behaviors and accidents on construction sites. Methods. In this work, results and findings from 56 related previous studies were investigated. These studies were categorized based on their design, type, methods of data collection, analytical methods, variables, and key findings. A qualitative content analysis procedure was used to extract variables, themes, and factors. In addition, all studies were reviewed to determine the quality rating and to evaluate the strength of provided evidence. Results. The content analysis identified 8 main categories: (a) society, (b) organization, (c) project management, (d) supervision, (e) contractor, (f) site condition, (g) work group, and (h) individual characteristics. The review highlighted the importance of more distal factors, e.g., society and organization, and project management, that may contribute to reducing the likelihood of unsafe behaviors and accidents through the promotion of site condition and individual features (as proximal factors). Conclusion. Further research is necessary to provide a better understanding of the links between unsafe behavior theories and empirical findings, challenge theoretical assumptions, develop new applied theories, and make stronger recommendations.

Automated Generation of Operations Level Construction Animations in Outdoor Augmented Reality

Three-dimensional 3D visualization is an effective tool for communicating, verifying, and validating the results of a simulated operation. Traditional visualization tools used for this purpose are typically based on the paradigm of virtual reality. Augmented reality AR is a relatively newer visualization paradigm whose engineering applications have been explored by a limited number of researchers. In this paper, the problem of generating smooth and continuous AR animations from the results of running discrete event simulation models and a general purpose methodology to overcome this challenge are discussed. The structure of an AR animation authoring language developed by the writers to create a logical link between a running simulation model and its corresponding 3D visualization in AR is described. In order to validate the functionality and effectiveness of the designed methods and animation language, an AR-based visualization application was developed and the designed algorithms were successfully tested using different simulation scenarios of varying visual and operational complexity. DOI: 10.1061/ ASCE 0887-3801 2009 23:6 405 CE Database subject headings: Construction sites; Graphic methods; Computer applications; Simulation; Computer graphics; Automation.

Scalable Algorithm for Resolving Incorrect Occlusion in Dynamic Augmented Reality Engineering Environments

@Augmented reality (AR) offers significant potential in construction, manufacturing, and other en- gineering disciplines that employ graphical visualization to plan and design their operations. As a result of intro- ducing real-world objects into the visualization, less vir- tual models have to be deployed to create a realistic visual output that directly translates into less time and effort re- quired to create, render, manipulate, manage, and update three-dimensional (3D) virtual contents (CAD model en- gineering) of the animated scene. At the same time, us- ing the existing layout of land or plant as the background of visualization significantly alleviates the need to collect data about the surrounding environment prior to creat- ing the final visualization while providing visually con- vincing representations of the processes being studied. In an AR animation, virtual and real objects must be simultaneously managed and accurately displayed to a user to create a visually convincing illusion of their co- existence and interaction. A critical challenge impeding this objective is the problem of incorrect occlusion that manifests itself when real objects in an AR scene par- tially or wholly block the view of virtual objects. In the ∗ To whom correspondence should be addressed. E-mail: vkamat

Visualization, Information Modeling, and Simulation: Grand Challenges in the Construction Industry

AbstractWith the rapid advancement of sensing and computing technology and the wide adoption of mobile computing, the construction industry has faced a rise in the amount of information and data generated during the lifecycle of the construction project. To deal with a large variety of project data and information to support efficient and effective decision making, visualization, information modeling, and simulation (VIMS) has become critical in the development of capital facilities and infrastructures. The objective of this paper is to identify and investigate grand challenges in VIMS for the construction industry, to assist the academic and industry communities in establishing a future research agenda to solve VIMS challenges. In particular, 17 VIMS grand challenges were identified by an expert task force in the VIMS committee of the ASCE Computing and Information Technology Division, and then VIMS experts in the civil and construction areas from both academia and industry participated in a survey to as...