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Recent reports on America's infrastructure have emphasized the importance of structural health monitoring of civil infrastructures. System identification is a key component of many structural health monitoring strategies. Current system identification methods estimate models of a structure by measuring displacements, accelerations, and strains with wired or wireless sensors. However, these methods typically involve installation of a limited number of sensors at discrete locations and require additional data acquisition devices. To overcome these limitations, computer vision-based techniques have been introduced recently that employ high-speed and high-resolution cameras. Such cameras can be quite costly and require tedious installation of targets. This paper investigates the potential of using consumer-grade cameras for structural system identification without the need to install targets. The underlying methods for target-free displacement measurements are introduced, including region of interest selection, feature detection, point tracking, and outlier removal. A set of experiments are conducted to assess the efficacy of the proposed approach by comparing the accuracy of the identified model with one obtained using a conventional wired system. Careful comparison of the results demonstrates the significant potential of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Timely and accurate monitoring of onsite construction operations can bring an immediate awareness on project specific issues. It provides practitioners with the information they need to easily and quickly make project control decisions. Despite their importance, the current practices are still time-consuming, costly, and prone to errors. To facilitate the process of collecting and analyzing performance data, researchers have focused on devising methods that can semi-automatically or automatically assess ongoing operations both at project level and operation level. A major line of work has particularly focused on developing computer vision techniques that can leverage still images, time-lapse photos and video streams for documenting the work in progress. To this end, this paper extensively reviews these state-of-the-art vision-based construction performance monitoring methods. Based on the level of information perceived and the types of output, these methods are mainly divided into two categories (namely project level: visual monitoring of civil infrastructure or building elements vs. operation level: visual monitoring of construction equipment and workers). The underlying formulations and assumptions used in these methods are discussed in detail. Finally the gaps in knowledge that need to be addressed in future research are identified. [ABSTRACT FROM AUTHOR]

Construction operations are highly energy-intensive and account for significant environmental impacts, including greenhouse gases (GHG) and other engine exhaust associated with material procurement/delivery and on-site construction activities. The opportunities for mitigating air pollutant emissions from construction operations can be captured by estimating and benchmarking during the preconstruction phase and then monitoring during the construction phase. However, a formal process model to manage the environmental aspects of on-site construction activities has yet to be clearly delineated, although recently several research efforts have appeared in relevant areas such as the development of in-use emission factors of construction equipment, methods for reliably estimating emissions at the project level, embodied carbon footprint benchmarking methods, and practical monitoring tools. Such a lack of a formal process model causes the misinterpretation of the benefits from recent research efforts in each area and hinders their implementation in practice. In this context, this paper aims to establish a framework model that could be a systematic and generic reference to the management of pollutant emissions from construction operations with state-of-the-art methods and tools. To do so, the paper identifies a generic process to be supported by research efforts in each area and presents an integrated framework based on the analysis of data connectivity between processes. An example of the indirect emission measurement is presented to demonstrate how data connectivity can be ensured between processes within the framework. [ABSTRACT FROM AUTHOR]

Numerous ecofeedback systems have been built around the proven principle that providing feedback to individuals about their energy use can lead to increased conservation through behavior change. This paper presents a novel ecofeedback system called Watt's Watts, which is designed to leverage the impacts of individual and social feedback to influence energy consumption behavior. Watt's Watts is one of the first ecofeedback systems that integrates individual-level, near-real-time energy consumption feedback within a social network environment and simultaneously collects network data that can be used to quantify social network effects on energy consumption. It was designed around two main goals: (1) to create a hardware/software integrated system that maximizes potential energy savings through behavior-based energy use reduction in residential buildings; (2) to collect data that will allow the validation of the user interface design and the examination of how social network dynamics impact energy consumption behavior. The objective of this paper is to introduce the concepts driving the design of the front and back ends of the novel Watt's Watts system to inform the design and development of future socially oriented ecofeedback systems. It explains the principles that directly informed the design of the system's interface, the methods by which the system's design is validated in numerous studies, how the back end system design enabled the robust analysis undertaken in the validation studies, and the future research avenues enabled by the development of this system. [ABSTRACT FROM AUTHOR]

Field construction can be planned, monitored, and controlled at two distinct levels: (1) the activity or schedule level; and (2) the operation or process level. Graphical three-dimensional (3D) visualization can serve as an effective communication method at both levels. Many research efforts in visualizing construction are rooted in scheduling. They typically involve linking activity-based construction schedules and 3D computer-aided design (CAD) models of facilities to describe discretely evolving construction product visualizations (often referred to as four-dimensional CAD). The focus is on communicating what components are built where and when, with the intention of studying the optimal activity sequence, spatial, and temporal interferences. The construction processes or operations actually involved in building the components are usually implied. A second approach in visualizing construction is rooted in discrete-event simulation that, in addition to visualizing evolving construction products, also concerns the visualization of the operations and processes that are performed in building them. In addition to what is built where and when, the approach communicates who builds it and how by depicting the interaction between involved machines, resources, and materials. This paper introduces the two approaches and describes the differences in concept, form, and content between activity level and operations level construction visualization. An example of a structural steel framing operation is presented to elucidate the comparison. This work was originally published in the proceedings of the 2002 IEEE Winter Simulation Conference. This paper expands on the original work by describing recent advances in both activity and operations level construction visualization. [ABSTRACT FROM AUTHOR]