PresenceSense: Zero-training Algorithm for Individual Presence Detection based on Power Monitoring

Non-intrusive presence detection of individuals in commercial buildings is much easier to implement than intrusive methods such as passive infrared, acoustic sensors, and camera. Individual power consumption, while providing useful feedback and motivation for energy saving, can be used as a valuable source for presence detection. We conduct pilot experiments in an office setting to collect individual presence data by ultrasonic sensors, acceleration sensors, and WiFi access points, in addition to the individual power monitoring data. PresenceSense (PS), a semi-supervised learning algorithm based on power measurement that trains itself with only unlabeled data, is proposed, analyzed and evaluated in the study. Without any labeling efforts, which are usually tedious and time consuming, PresenceSense outperforms popular models whose parameters are optimized over a large training set. The results are interpreted and potential applications of PresenceSense on other data sources are discussed. The significance of this study attaches to space security, occupancy behavior modeling, and energy saving of plug loads.Comment: BuildSys 201

Fall prevention intervention technologies: A conceptual framework and survey of the state of the art

In recent years, an ever increasing range of technology-based applications have been developed with the goal of assisting in the delivery of more effective and efficient fall prevention interventions. Whilst there have been a number of studies that have surveyed technologies for a particular sub-domain of fall prevention, there is no existing research which surveys the full spectrum of falls prevention interventions and characterises the range of technologies that have augmented this landscape. This study presents a conceptual framework and survey of the state of the art of technology-based fall prevention systems which is derived from a systematic template analysis of studies presented in contemporary research literature. The framework proposes four broad categories of fall prevention intervention system: Pre-fall prevention; Post-fall prevention; Fall injury prevention; Cross-fall prevention. Other categories include, Application type, Technology deployment platform, Information sources, Deployment environment, User interface type, and Collaborative function. After presenting the conceptual framework, a detailed survey of the state of the art is presented as a function of the proposed framework. A number of research challenges emerge as a result of surveying the research literature, which include a need for: new systems that focus on overcoming extrinsic falls risk factors; systems that support the environmental risk assessment process; systems that enable patients and practitioners to develop more collaborative relationships and engage in shared decision making during falls risk assessment and prevention activities. In response to these challenges, recommendations and future research directions are proposed to overcome each respective challenge.The Royal Society, grant Ref: RG13082

Effects of video-conferencing on gaze behavior and communication

Through the use of eye-tracking and conversation analysis this study examined the impact of video-conferencing on communication. Paired participants performed a collaborative task over four communication media: face-to-face; desktop video-conferencing with eye contact; and life-size video-conferencing with and without eye contact. Participants more frequently checked the information their partner verbally relayed when communicating face-to-face and over life-size video-conferencing with eye contact. They also looked more at their partner when conversing over life-size video-conferencing with eye contact compared to the other conditions. The results imply that the mode across which we communicate does influence our verbal and non-verbal interactions but that people still prefer to talk face-to-face

Hedonic Price Indexes for Personal Computer Operating Systems and Productivity Suites

Results of hedonic price regressions for personal computer operating systems and productivity suites advertised in PC World magazine by retail vendors during the time period 1984 to 2000 are reported. Among the quality attribute variables we use are new measures capturing the presence of network effects in personal computer operating systems, such as connectivity and compatibility, and product integration among components of productivity suites. Average annual growth rates of quality-adjusted prices of personal computer operating systems range from -15 to -18 percent, while those for productivity suites generally range between -13 and -16 percent. Price declines are generally greater in the latter half of the samples.

The Effect of Endgame Tablebases on Modern Chess Engines

Modern chess engines have the ability to augment their evaluation by using massive tables containing billions of positions and their memorized solutions. This report examines the importance of these tables to better understand the circumstances under which they should be used. The analysis conducted in this paper empirically examines differences in size and speed of memorized positions and their impacts on engine strength. Using this technique, situations where memorized tables improve play (and situations where they do not) are discovered

Evaluating Material Consumption at the Intersection of Technological Innovation and Shifting Consumer Demand: A Case Study of Consumer Electronics

Increasing availability of consumer electronics offers the potential to improve quality of life, extend educational access, and improve efficiency of industrial processes, yet introduce their own set of challenges including increasingly diverse material supply chains, the fastest growing waste stream, and high life cycle resource demands. A significant body of research has been developed to understand material and energy flows across the product life cycle, but to date, that research has neglected to understand aggregate material flows across a community of interrelated products that are consumed, used, and disposed of together. This research explores that research gap, first evaluating the possibility of natural dematerialization due to technological innovation as a means of reducing material flows across the life cycle. A case study of a laptop computer over subsequent generations reveals that innovation is being realized as improved performance, rather than reduced material consumption, and thus total product mass is relatively constant over time. Extending the boundaries of the study from a single product over time to a group of products that interact within the average U.S. household reveals that, although per product material consumption stays relatively constant over time, community consumption increases as more products are consumed. Similar research has been conducted evaluating energy consumption by a community of products, resulting in a recommendation for a more energy efficient community of products. Lack of data linking community structure and consumption choices, however, raises the question of whether consumers would willingly adopt these alternative communities. Therefore, the final phase of the research collects data regarding consumption choices, product interactions, and changes in community structure, and models changes in community structure as the result of increasing technological awareness and improved product quality. The results from the model indicate that these types of improvements may shift the community structure, they do little to reduce community material consumption. Future research efforts should be directed at “closing the loop” and improving material recovery and recycling, in addition to educating consumers to move them toward more sustainable consumption (i.e. in general, consuming less)

Faster, Smaller, Cheaper: An Hedonic Price Analysis of PDAs

We compute quality-adjusted price indexes for Personal Digital Assistants (PDAs) for the period 1999-2004, using data on prices and characteristics of 203 models sold by 12 manufacturers. The PDA market is growing in size, it is technologically dynamic with very substantial changes in measured characteristics over time, and it has experienced rapid rates of product introduction. Hedonic regressions consistently show prices to be positively related to processor performance, RAM memory, permanent storage capacity, and battery life, as well as several measures of screen size and quality. Features such as networking, biometric identification, camera, and cellphone capability are also positively associated with price. Hedonic price indexes implied by these regressions decline at an AAGR of 21.1% to 25.6% per year during this period. A matched model price index computed from a subset of observations declines at 18.75% per year. Though these PDA rates of price decline are lower than have been estimated for desktop and laptop PCs, consumers in this "ultra-portable" segment of the computer market appear to have enjoyed substantial welfare gains over the past five years.