Benefits Realization Management of Computer Vision in Construction:A Missed,Yet Not Lost,Opportunity

1.Introduction While the applications of computer visions are varied in construction,research has tended to focus on measuring the accuracy of object detectors such as faster region-based-convolution neural networks(Faster R-CNN)and single shot detector algorithms(SDD)[1].Limited,if any,attention has focused on determining the benefits of such technology in construction beyond the claims that it can help detect problems quickly and accurately.Reinforcing this point are the numerous review papers that have frequented the literature[2,3].

State of Science:Why Does Rework Occur in Construction?What Are Its Consequences?And What Can be Done to Mitigate Its Occurrence?

There has been a wealth of research that has examined the nature of rework in construction.Progress toward addressing the rework problem has been limited-it still plagues practice,adversely impacting a project’s performance.Almost all rework studies have focused on determining its proximal or root causes and therefore have overlooked the conditions that result from its manifestation.In filling this void,this paper draws upon our previous empirical studies,amongst others,to provide a much-needed theoretical framing to understand better why rework occurs,what its consequences are,and how it can be mitigated during construction.The theoretical framing we derive from our review provides construction organizations and their projects with a realization that the journey to mitigating rework begins with creating an error-mastery culture comprising authentic leadership,psychological safety,an errormanagement orientation,and resilience.We suggest that,once an error-mastery culture is established within construction organizations and their projects,they will be better positioned to realize the benefits of the techniques,tools,and technologies espoused to address rework,such as the Last Planner® and building information modeling.We also provide directions for future research and identify implications for practice so that strides toward rework mitigation in construction can be made.

On-site solar PV generation and use: Self-consumption andself-sufficiency

As energy storage systems are typically not installed with residential solar photovoltaic (PV) systems,any “excess” solar energy exceeding the house load remains unharvested or is exported to the grid.This paper introduces an approach towards a system design for improved PV self-consumptionand self-sufficiency. As a result, a polyvalent heat pump, offering heating, cooling and domestic hotwater, is considered alongside water storage tanks and batteries. Our method of system analysisbegins with annual hourly thermal loads for heating and cooling a typical Australian house inGeelong, Victoria. These hourly heating and cooling loads are determined using Transient SystemSimulation (TRNSYS) software. The house’s annual hourly electricity consumption is analysed usingsmart meter data downloaded from the power supplier and PV generation data measured with aPV system controller. The results reveal that the proposed system could increase PV self-consumptionand self-sufficiency to 41.96% and 86.34%, respectively, resulting in the annual imported energybeing reduced by about 74%. The paper also provides sensitivity analyses for the hot and coldstorage tank sizes, the coefficient of performance of the heat pump, solar PV and battery sizes.After establishing the limits of thermal storage size, a significant impact on self-efficiency can berealised through battery storage. This study demonstrates the feasibility of using a polyvalent heatpump together with water storage tanks and, ultimately, batteries to increase PV self-consumptionand self-sufficiency. Future work will concentrate on determining a best-fit approach to systemsizing embedded within the TRNSYS simulation tool.

Model server enabled management of collaborative changes in building information models

The issues and challenges involved in controlling the collaborative changes in a Building Information Modeling(BIM) data repository, in a multi-model collaboration environment, are discussed. It is suggested that managing iterative changes in BIMs is a database problem, exacerbated by the long transaction times needed to support collaborative design progression. This is yet to be resolved in the construction industry and better solutions are needed to support the underlying workflows and computing operations for seamless collaboration on BIMs. With this in mind, this paper proposes the use of the structural and semantic characteristics of BIM objects as a mechanism for tracking changes across co-developed solutions. The creation of object signatures, using hash codes derived from their characteristics, provides a potential mechanism for object comparison and effective change recognition and management.