Material waste has been recognized as a major problem in the construction industry that has important implications both for the efficiency industry and for the environmental impact of construction projects. Moreover, waste measurement plays an important role in the management of production systems since it is an effective way to assess their performance, allowing areas of potential improvement to be pointed out. This paper describes the main results of two research studies carried out in Brazil that investigated the occurrence of material waste at 74 building sites located in different regions of that country. Some typical figures for the waste of some key construction materials are provided, and the main causes of waste in the sector are discussed. The results indicate that the waste of materials in the Brazilian building industry is fairly high and that a large variability in waste incidence is found across different projects. Most of this waste can be avoided by implementing inexpensive preventive measures, mostly related to managerial improvements.

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SummaryNonintrusive load monitoring (NILM) is a technique for deducing the power consumption and operational schedule of individual loads in a building from measurements of the overall voltage and current feeding it, using information and communication technologies. In this article, we review the potential of this technology to enhance residential electricity audits. First, we review the currently commercially available whole-house and plug-level technology for residential electricity monitoring in the context of supporting audits. We then contrast this with NILM and show the advantages and disadvantages of the approach by discussing results from a prototype system installed in an apartment unit. Recommendations for improving the technology to allow detailed, continuous appliance-level auditing of residential buildings are provided, along with ideas for possible future work in the field.

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We present Sensor Andrew, a multidisciplinary campus-wide scalable sensor network that is designed to host a wide range of sensor, actuator and low-power applications. The goals of Sensor Andrew are to support ubiquitous large-scale monitoring, operation and control of infrastructure in a way that is extensible, easy to use, and secure while maintaining privacy. Target applications currently being developed as part of Sensor Andrew include builing emergency, first-responder support, quality of life for the disabled, monitoring and optimization of water distribution systems, building power monitoring and control, social networking, and biometric sensors for campus security. Sensing devices that are used range from cameras and batteryoperated sensor nodes to energy-monitoring devices wired into building power supplies. Some of these sensing devices may also be mobile and require hand-off between different networked regions. Supporting multiple applications and heterogeneous devices requires a standardized communication medium capable of scaling to tens of thousands of sources. In this technical report, we present the architecture underlying Sensor Andrew for managing sensor data collection as well as server-side application interactions. Sensors and actuators are modeled as event nodes in a push-based publish-subscribe architecture. A data handler provides registration, discovery and data logging facilities for each device. The major elements of this architecture have been deployed in five buildings at Carnegie Mellon University, and are comprised of over 1000 sensing points reporting data from multiple communication interfaces. Finally, we describe two different case study applications currently using the infrastructure that benefit from shared information. Design choices, limitations and enhancements across various layers and protocols are also discussed.

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