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UBICOMP Tables of Contents: 01020304050607080910111213-113-214-114-215

Proceedings of the 2009 International Conference on Ubiquitous Computing

Fullname:Proceedings of the 11th International Conference on Ubiquitous Computing
Editors:Hans Gellersen; Sunny Consolvo
Location:Orlando, Florida, USA
Dates:2009-Sep-30 to 2009-Oct-03
Publisher:ACM
Standard No:ISBN 1-60558-431-2, 978-1-60558-431-7; ACM DL: Table of Contents hcibib: UBICOMP09
Papers:31
Pages:276
Links:Conference Home Page
  1. Places & location
  2. Activity recognition
  3. Notes
  4. Security & access
  5. UbiComp worldwide
  6. Behavior change
  7. Context-aware & wearable systems
  8. Sensing & sustainability

Places & location

From spaces to places: emerging contexts in mobile privacy BIBAKFull-Text 1-10
  Clara Mancini; Keerthi Thomas; Yvonne Rogers; Blaine A. Price; Lukazs Jedrzejczyk; Arosha K. Bandara; Adam N. Joinson; Bashar Nuseibeh
Mobile privacy concerns are central to Ubicomp and yet remain poorly understood. We advocate a diversified approach, enabling the cross-interpretation of data from complementary methods. However, mobility imposes a number of limitations on the methods that can be effectively employed. We discuss how we addressed this problem in an empirical study of mobile social networking. We report on how, by combining a variation of experience sampling and contextual interviews, we have started focusing on a notion of context in relation to privacy, which is subjectively defined by emerging socio-cultural knowledge, functions, relations and rules. With reference to Gieryn's sociological work, we call this place, as opposed to a notion of context that is objectively defined by physical and factual elements, which we call space. We propose that the former better describes the context for mobile privacy.
Keywords: context, contextual interview, experience sampling, facebook, memory phrase, mobile privacy, place
The commodification of location: dynamics of power in location-based systems BIBAKFull-Text 11-20
  Irina Shklovski; Janet Vertesi; Emily Troshynski; Paul Dourish
Location-based ubiquitous computing systems are entering mainstream society and becoming familiar parts of everyday life. However, the settings in which they are deployed are already suffused with complex social dynamics. We report on a study of parole officers and parolees whose relationships are being transformed by location-based technologies. While parolees are clearly subjects of state discipline, the parole officers also find themselves subject to new responsibilities. This study highlights the complexities of power in sociotechnical systems and what happens when location becomes a tradable, technological object.
Keywords: discipline, gps, power, surveillance
Discovering semantically meaningful places from pervasive RF-beacons BIBAKFull-Text 21-30
  Donnie H. Kim; Jeffrey Hightower; Ramesh Govindan; Deborah Estrin
Detecting visits to semantically meaningful places is important for many emerging mobile applications. We present PlaceSense, a place discovery algorithm suitable for mobile devices that exploits pervasive RF-beacons. By relying on separate mechanisms to detect entrance to and departure from a place and buffering overlapping data for subsequent visits, it is more robust than the state-of-the-art, especially in detecting short visits, places where people are mobile, or where inconsistent beacons are prevalent due to interference. We experimentally evaluate PlaceSense's effectiveness in discovering semantically meaningful places, and compare with other approaches that use coordinates or RF-beacon fingerprints. Our results demonstrate that PlaceSense correctly discovers 92% (compared to between 28% and 65% for previous work) of the visited places and accurately detects their entrance and departure times from both real-life and scripted data sets.
Keywords: beacon traces, location, place learning
Privately querying location-based services with SybilQuery BIBAKFull-Text 31-40
  Pravin Shankar; Vinod Ganapathy; Liviu Iftode
To usefully query a location-based service, a mobile device must typically present its own location in its query to the server. This may not be acceptable to clients that wish to protect the privacy of their location. This paper presents the design and implementation of SybilQuery, a fully decentralized and autonomous k-anonymization-based scheme to privately query location-based services. SybilQuery is a client-side tool that generates k-1 Sybil queries for each query by the client. The location-based server is presented with a set of k queries and is unable to distinguish between the client's query and the Sybil queries, thereby achieving k-anonymity. We tested our implementation of SybilQuery on real mobility traces of approximately 500 cabs in the San Francisco Bay area. Our experiments show that SybilQuery can efficiently generate Sybil queries and that these queries are indistinguishable from real queries.
Keywords: anonymity, location-based services, privacy, vehicular computing

Activity recognition

Eye movement analysis for activity recognition BIBAKFull-Text 41-50
  Andreas Bulling; Jamie A. Ward; Hans Gellersen; Gerhard Tröster
In this work we investigate eye movement analysis as a new modality for recognising human activity. We devise 90 different features based on the main eye movement characteristics: saccades, fixations and blinks. The features are derived from eye movement data recorded using a wearable electrooculographic (EOG) system. We describe a recognition methodology that combines minimum redundancy maximum relevance feature selection (mRMR) with a support vector machine (SVM) classifier. We validate the method in an eight participant study in an office environment using five activity classes: copying a text, reading a printed paper, taking hand-written notes, watching a video and browsing the web. In addition, we include periods with no specific activity. Using a person-independent (leave-one-out) training scheme, we obtain an average precision of 76.1% and recall of 70.5% over all classes and participants. We discuss the most relevant features and show that eye movement analysis is a rich and thus promising modality for activity recognition.
Keywords: activity recognition, electrooculography (eog), eye movement analysis, wearable computing
Recognizing daily activities with RFID-based sensors BIBAKFull-Text 51-60
  Michael Buettner; Richa Prasad; Matthai Philipose; David Wetherall
We explore a dense sensing approach that uses RFID sensor network technology to recognize human activities. In our setting, everyday objects are instrumented with UHF RFID tags called WISPs that are equipped with accelerometers. RFID readers detect when the objects are used by examining this sensor data, and daily activities are then inferred from the traces of object use via a Hidden Markov Model. In a study of 10 participants performing 14 activities in a model apartment, our approach yielded recognition rates with precision and recall both in the 90% range. This compares well to recognition with a more intrusive short-range RFID bracelet that detects objects in the proximity of the user; this approach saw roughly 95% precision and 60% recall in the same study. We conclude that RFID sensor networks are a promising approach for indoor activity monitoring.
Keywords: activity detection, rfid, sensor networks, wisp
Cross-domain activity recognition BIBAKFull-Text 61-70
  Vincent Wenchen Zheng; Derek Hao Hu; Qiang Yang
In activity recognition, one major challenge is huge manual effort in labeling when a new domain of activities is to be tested. In this paper, we ask an interesting question: can we transfer the available labeled data from a set of existing activities in one domain to help recognize the activities in another different but related domain? Our answer is "yes", provided that the sensor data from the two domains are related in some way. We develop a bridge between the activities in two domains by learning a similarity function via Web search, under the condition that the sensor data are from the same feature space. Based on the learned similarity measures, our algorithm interprets the data from the source domain as the data in the domain with different confidence levels, thus accomplishing the cross-domain knowledge transfer task. Our algorithm is evaluated on several real-world datasets to demonstrate its effectiveness.
Keywords: activity recognition, cross domain, transfer learning, web search
Recognizing stereotypical motor movements in the laboratory and classroom: a case study with children on the autism spectrum BIBAKFull-Text 71-80
  Fahd Albinali; Matthew S. Goodwin; Stephen S. Intille
Individuals with Autism Spectrum Disorders (ASD) frequently engage in stereotyped and repetitive motor movements. Automatically detecting these movements in real-time using comfortable, miniature wireless sensors could advance autistic research and enable new intervention tools for the classroom that help children and their caregivers monitor and cope with this potentially problematic class of behavior. We present activity recognition results for stereotypical hand flapping and body rocking using data collected from six children with ASD repeatedly observed in both laboratory and classroom settings. In the classroom, an overall recognition accuracy of 88.6% (TP: 0.85; FP: 0.08) was achieved using three sensors. Challenges encountered when applying machine learning to this domain, as well as implications for the development of real-time classroom interventions and research tools, are discussed.
Keywords: accelerometers, activity recognition, autism

Notes

inAir: measuring and visualizing indoor air quality BIBAKFull-Text 81-84
  Sunyoung Kim; Eric Paulos
Good indoor air quality is a vital part of human health. Poor indoor air quality can contribute to the development of chronic respiratory diseases such as asthma, heart disease, and lung cancer. Complicating matters, poor air quality is extremely difficult for humans to detect through sight and smell alone and existing sensing equipment is designed to be used by and provide data for scientists rather than everyday citizens. We propose inAir, a tool for measuring, visualizing, and learning about indoor air quality. inAir provides historical and real-time visualizations of indoor air quality by measuring tiny hazardous airborne particles as small as 0.5 microns in size. Through user studies we demonstrate how inAir promotes greater awareness and motivates individual actions to improve indoor air quality.
Keywords: air quality, domestic computing, health, sustainability
Wearable therapist: sensing garments for supporting children improve posture BIBAKFull-Text 85-88
  Holger Harms; Oliver Amft; Gerhard Tröster; Mirjam Appert; Roland Müller; Andreas Meyer-Heim
This paper introduces a sensing garment to support posture coaching in children. The system measures back bending postures using acceleration sensors embedded in the garment. We present a sensing garment architecture and the evaluation of garments of different sizes in a study with 21 children. A vision-based reference system was used to evaluate sensor positions and measurement accuracy for 54 back bending postures and related head positions. Then, we asked eight physiotherapists to rate the children's back postures in this study. Ratings of experts correlated significantly with the back bending measurements obtained from the garment. The garment enables an objective assessment of back postures and could form the basis of a system that provides coaching feedback to improve postural control in children.
Keywords: back posture, rehabilitation, smart garments, smash
Sonar-based measurement of user presence and attention BIBAKFull-Text 89-92
  Stephen P. Tarzia; Robert P. Dick; Peter A. Dinda; Gokhan Memik
We describe a technique to detect the presence of computer users. This technique relies on sonar using hardware that already exists on commodity laptop computers and other electronic devices. It leverages the fact that human bodies have a different effect on sound waves than air and other objects. We conducted a user study in which 20 volunteers used a computer equipped with our ultrasonic sonar software. Our results show that it is possible to detect the presence or absence of users with near perfect accuracy after only ten seconds of measurement. We find that this technique can differentiate varied user positions and actions, opening the possibility of future use in estimating attention level.
Keywords: attention, presence, sonar, ultrasonics, user study
Simultaneous localization and mapping for pedestrians using only foot-mounted inertial sensors BIBAKFull-Text 93-96
  Patrick Robertson; Michael Angermann; Bernhard Krach
In this paper we describe a new Bayesian estimation approach for simultaneous mapping and localization for pedestrians based on odometry with foot mounted inertial sensors. When somebody walks within a constrained area such as a building, then even noisy and drift-prone odometry measurements can give us information about features like turns, doors, and walls, which we can use to build a form of a map of the explored area, especially when these features are revisited over time. Our initial results for our novel scheme which we call "FootSLAM" are very surprising in that true SLAM with stable relative positioning accuracy of 1-2 meters for pedestrians is indeed possible based on inertial sensors alone without any prior known building indoor layout. Furthermore, the 2D maps obtained even for just 10 minutes of walking converge to a good approximation of the true layout forming the basis for future automated collaborative mapping of buildings.
Keywords: ins-based positioning, odometry, indoor positioning, pedestrian navigation, simultaneous localization and mapping
BlueTone: a framework for interacting with public displays using dual-tone multi-frequency through bluetooth BIBAKFull-Text 97-100
  David Dearman; Khai N. Truong
Large information displays are common in public and semi-public spaces but still require rapid and lightweight ways for users to interact with them. We present BlueTone, a framework for developing large display applications which will interpret and react to dual-tone multi-frequency sounds transmitted from mobile phones paired with the display using the Bluetooth headset profile. BlueTone enables text entry, cursor manipulation and menu selection without requiring the installation of any special software on a user's mobile phone.
Keywords: at a distance interaction, bluetone, bluetooth, public display
Toward emergent technology for blended public displays BIBAKFull-Text 101-104
  Angie Chandler; Joe Finney; Carl Lewis; Alan Dix
Public displays are becoming increasingly commonplace, yet recent studies place the effectiveness and user acceptance of them into doubt. This paper motivates the need for a new class of display technology that can more effectively blend with its environment and introduces the concept of self-organizing emergent displays as a vehicle to achieving this. The paper goes on to briefly describe Firefly, a prototype emergent display system, and evaluate its scalability, effectiveness, and user acceptance through experimental analysis and a field trial.
Keywords: emergent, field trial, firefly, public display, self-organizing

Security & access

A spotlight on security and privacy risks with future household robots: attacks and lessons BIBAKFull-Text 105-114
  Tamara Denning; Cynthia Matuszek; Karl Koscher; Joshua R. Smith; Tadayoshi Kohno
Future homes will be populated with large numbers of robots with diverse functionalities, ranging from chore robots to elder care robots to entertainment robots. While household robots will offer numerous benefits, they also have the potential to introduce new security and privacy vulnerabilities into the home. Our research consists of three parts. First, to serve as a foundation for our study, we experimentally analyze three of today's household robots for security and privacy vulnerabilities: the WowWee Rovio, the Erector Spykee, and the WowWee RoboSapien V2. Second, we synthesize the results of our experimental analyses and identify key lessons and challenges for securing future household robots. Finally, we use our experiments and lessons learned to construct a set of design questions aimed at facilitating the future development of household robots that are secure and preserve their users' privacy.
Keywords: cyber-physical systems, domestic robots, household robots, multi-robot attack, privacy, robots, security, single-robot attack, ubiquitous robots
Authenticating ubiquitous services: a study of wireless hotspot access BIBAKFull-Text 115-124
  Tim Kindberg; Chris Bevan; Eamonn O'Neill; James Mitchell; Jim Grimmett; Dawn Woodgate
This paper concerns the problem of phishing attacks in ubiquitous computing environments. The embedding of ubiquitous services into our everyday environments may make fake services seem plausible but it also enables us to authenticate them with respect to those environments. We propose physical and virtual linkage as two types of authenticating evidence in ubiquitous environments and two protocols based on them. We describe an experiment to test hypotheses concerning user responses to physical and virtual linkage with respect to fake Wi-Fi hotspots. Based on our experience we derive an improved protocol for authenticating spontaneously accessed ubiquitous services.
Keywords: authentication, phishing, ubiquitous services, wi-fi
SessionMagnifier: a simple approach to secure and convenient kiosk browsing BIBAKFull-Text 125-134
  Chuan Yue; Haining Wang
Many people use public computers to browse the Web and perform important online activities. However, public computers are usually far less trustworthy than peoples' own computers because they are more vulnerable to various security attacks. In this paper, we propose SessionMagnifier, a simple approach to secure and convenient kiosk browsing. The key idea of SessionMagnifier is to enable an extended browser on a mobile device and a regular browser on a public computer to collaboratively support a Web session. This approach simply requires a SessionMagnifier browser extension to be installed on a trusted mobile device. A user can securely perform sensitive interactions on the mobile device and conveniently perform other browsing interactions on the public computer. We implemented SessionMagnifier for Mozilla's Fennec browser and evaluated it on a Nokia N810 Internet Tablet. Our evaluation and analysis demonstrate that SessionMagnifier is simple, secure, and usable.
Keywords: ajax, kiosk, mobile device, security, usability, web browsing
Understanding file access mechanisms for embedded Ubicomp collaboration interfaces BIBAKFull-Text 135-144
  Anthony Collins; Anastasia Bezerianos; Gregor McEwan; Markus Rittenbruch; Rainer Wasinger; Judy Kay
This paper explores the nature of interfaces to support people in accessing their files at tabletop displays embedded in the environment. To do this, we designed a study comparing people's interaction with two very different classes of file system access interface: Focus, explicitly designed for tabletops, and the familiar hierarchical Windows Explorer. In our within-subjects double-crossover study, participants collaborated on 4 planning tasks. Based on video, logs, questionnaires and interviews, we conclude that both classes of interface have a place. Notably, Focus contributed to improved collaboration and more efficient use of the workspace than with Explorer. Our results inform a set of recommendations for future interfaces enabling this important class of interaction -- supporting access to files for collaboration at tabletop devices embedded in an ubicomp environment.
Keywords: file system ui, single display groupware, tabletop interface

UbiComp worldwide

Broadening Ubicomp's vision: an exploratory study of charismatic pentecostals and technology use in Brazil BIBAKFull-Text 145-154
  Susan P. Wyche; Camila M. Magnus; Rebecca E. Grinter
We present results from a qualitative study examining how Charismatic Pentecostals use Information and Communications Technologies (ICTs) in São Paulo, Brazil. This work contributes to the growing body of research that broadens Weiser's vision by exploring technology use in novel and unfamiliar contexts. Our findings reveal how "extreme" and non-rational beliefs frame users' ICT experiences. We argue that if ubicomp is to be global and ubiquitous, accounting for alternative value systems is necessary. We discuss the implications of our findings and present issues the ubicomp community should consider when imagining a future that includes users from parts of the global south.
Keywords: hci4d, religious technology, user experience
Ubicomp4D: infrastructure and interaction for international development -- the case of urban indian slums BIBAKFull-Text 155-164
  Nithya Sambasivan; Nimmi Rangaswamy; Ed Cutrell; Bonnie Nardi
This paper attempts to re-imagine ubiquitous computing for populations in low-income and information-challenged environments. We examine information infrastructures in mid-sized urban slums of Mumbai and Bangalore in three ways -- 1) highlighting technologies supporting social networks, 2) examining underlying notions of trust and privacy in building information networks, and 3) discussing protocols and practices around shared access. We then discuss our thoughts on designing for low-income, low-literacy, and resource-challenged communities, presenting new ways to think about the design of ubiquitous technologies for international development. We argue for collaborative exchange between the established strengths of the Information and Communication Technologies for Development (ICT4D) and Ubicomp communities to generate new ways of shaping technologies towards poverty alleviation in previously neglected socio-economic contexts -- Ubicomp4D.
Keywords: ict4d, india, low-income communities, mobile technologies, privacy, trust, ubicomp4d, urban slums
Encountering SenseCam: personal recording technologies in everyday life BIBAKFull-Text 165-174
  David H. Nguyen; Gabriela Marcu; Gillian R. Hayes; Khai N. Truong; James Scott; Marc Langheinrich; Christof Roduner
In this paper, we present a study of responses to the idea of being recorded by a ubicomp recording technology called SenseCam. This study focused on real-life situations in two North American and two European locations. We present the findings of this study and their implications, specifically how those who might be recorded perceive and react to SenseCam. We describe what system parameters, social processes, and policies are required to meet the needs of both the primary users and these secondary stakeholders and how being situated within a particular locale can influence responses. Our results indicate that people would tolerate potential incursions from SenseCam for particular purposes. Furthermore, they would typically prefer to be informed about and to consent to recording as well as to grant permission before any data is shared. These preferences, however, are unlikely to instigate a request for deletion or other action on their part. These results inform future design of recording technologies like SenseCam and provide a broader understanding of how ubicomp technologies might be taken up across different cultural and political regions.
Keywords: experience sampling, paratyping, privacy, sensecam

Behavior change

Applying pervasive technologies to create economic incentives that alter consumer behavior BIBAKFull-Text 175-184
  Tetsuo Yamabe; Vili Lehdonvirta; Hitoshi Ito; Hayuru Soma; Hiroaki Kimura; Tatsuo Nakajima
Economic incentives are a powerful way of shaping consumer behavior towards more commercially efficient and environmentally sustainable patterns. In this paper, we explore the idea of combining pervasive computing techniques with electronic payment systems to create activity-based micro-incentives. Users who consume additional resources by e.g., occupying an air-conditioned space instead of a normal space are levied additional micro-payments. In an alternative approach, consumers who choose to save resources are rewarded with micro-rebates off the price of a service. As a result, the cost of using a service corresponds more closely with the resources used, leading market mechanisms to allocate resources efficiently. A key challenge is designing incentive mechanisms that alter consumer behavior in the desired fashion. We introduce four incentive models, and present evaluation results suggesting that consumers make different decisions depending on which model is used.
Keywords: activity-based micro-pricing, economic incentives, micropayments, mobile payment, persuasive technology, virtual currency
Playful bottle: a mobile social persuasion system to motivate healthy water intake BIBAKFull-Text 185-194
  Meng-Chieh Chiu; Shih-Ping Chang; Yu-Chen Chang; Hao-Hua Chu; Cheryl Chia-Hui Chen; Fei-Hsiu Hsiao; Ju-Chun Ko
This study of mobile persuasion system explores the use of a mobile phone, when attached to an everyday object used by an everyday behavior, becomes a tool to sense and influence that behavior. This mobile persuasion system, called Playful Bottle system, makes use of a mobile phone attached to an everyday drinking mug and motivates office workers to drink healthy quantities of water. A camera and accelerometer sensors in the phone are used to build a vision/motion-based water intake tracker to detect the amount and regularity of water consumed by the user. Additionally, the phone includes hydration games in which natural drinking actions are used as game input. Two hydration games are developed: a single-user TreeGame with automated computer reminders and a multi-user ForestGame with computer-mediated social reminders from members of the group playing the game. Results from 7-week user study with 16 test subjects suggest that both hydration games are effective for encouraging adequate and regular water intake by users. Additionally, results of this study suggest that adding social reminders to the hydration game is more effective than system reminders alone.
Keywords: hydration behavior, mobile computing, persuasive technology, ubiquitous computing

Context-aware & wearable systems

Assessing demand for intelligibility in context-aware applications BIBAKFull-Text 195-204
  Brian Y. Lim; Anind K. Dey
Intelligibility can help expose the inner workings and inputs of context-aware applications that tend to be opaque to users due to their implicit sensing and actions. However, users may not be interested in all the information that the applications can produce. Using scenarios of four real-world applications that span the design space of context-aware computing, we conducted two experiments to discover what information users are interested in. In the first experiment, we elicit types of information demands that users have and under what moderating circumstances they have them. In the second experiment, we verify the findings by soliciting users about which types they would want to know and establish whether receiving such information would satisfy them. We discuss why users demand certain types of information, and provide design implications on how to provide different intelligibility types to make context-aware applications intelligible and acceptable to users.
Keywords: context-aware, explanations, intelligibility, satisfaction
Interactive dirt: increasing mobile work performance with a wearable projector-camera system BIBAKFull-Text 205-214
  Daniel C. McFarlane; Steven M. Wilder
Mobile teamwork requires people to maintain good situational awareness (SA) about their real world environments. Current mobile devices are highly portable, but their user interfaces (UIs) require too deep of focus of attention to allow their users to use them and simultaneously maintain SA. As a result, some mobile practitioners have little or no access to useful computer-based interactive services. Inspired by existing projector-camera systems, this paper studies the feasibility of developing a wearable projector-camera system that enables users to access human-computer interaction (HCI) services without negatively affecting their SA. A functional prototype of the "Interactive Dirt" system was developed using inexpensive commercial off-the-shelf technologies. A field experiment was conducted as a formative evaluation to test the utility of the prototype under extreme mobile teamwork requirements for SA -- military stability and support operations (SASO). Results show strong potential to increase performance of mobile teams.
Keywords: mobile computing, projector-camera system, situational impairment, wearable user interface
SwimMaster: a wearable assistant for swimmer BIBAKFull-Text 215-224
  Marc Bächlin; Kilian Förster; Gerhard Tröster
In this paper we introduce the concept of a wearable assistant for swimmer, called SwimMaster. The SwimMaster consists of acceleration sensors with micro-controllers and feedback interface modules that swimmer wear while swimming. With four different evaluation studies and a total of 22 subjects we demonstrate the functionality and power of the SwimMaster system. We show how a wide range of swim parameters can be monitored and used for a continuous swim performance evaluation. These parameters include the time per lane, the swimming velocity and the number of strokes per lane. Also swim style specific factors like the body balance and the body rotation are extracted. Finally three feedback modalities are tested and evaluated. With these means we show the ability of the SwimMaster to assist a swimmer in achieving the desired exercise goals by constantly monitoring his/her swim performance and providing the necessary feedback to achieve the desired workout goals.
Keywords: context recognition, feedback, performance evaluation, swimming, wearable system
Validated caloric expenditure estimation using a single body-worn sensor BIBAKFull-Text 225-234
  Jonathan Lester; Carl Hartung; Laura Pina; Ryan Libby; Gaetano Borriello; Glen Duncan
In 2007, approximately 30% of US adults were obese, with related health care costs exceeding 100 billion dollars. Clearly, the obesity epidemic represents a growing societal concern. One challenge in weight control is the difficulty of tracking food calories consumed and calories expended by activity. This paper presents a system for automatic monitoring of calories expended using a single body-worn accelerometer. Our system uses activity inference combined with signal analysis to estimate calories expended in real-time using regression formulas developed by the American College of Sports Medicine. To validate our system, we have collected data from 51 subjects in a laboratory setting using a treadmill and a more natural field test. Actual caloric expenditure was determined using the medical "gold standard" measurement, of oxygen consumption. We are able to achieve 89% accuracy with lab data and 79% with field data -- both high enough to be useful in practice.
Keywords: caloric balance, long term health monitoring, pervasive health, wellness

Sensing & sustainability

HydroSense: infrastructure-mediated single-point sensing of whole-home water activity BIBAKFull-Text 235-244
  Jon E. Froehlich; Eric Larson; Tim Campbell; Conor Haggerty; James Fogarty; Shwetak N. Patel
Recent work has examined infrastructure-mediated sensing as a practical, low-cost, and unobtrusive approach to sensing human activity in the physical world. This approach is based on the idea that human activities (e.g., running a dishwasher, turning on a reading light, or walking through a doorway) can be sensed by their manifestations in an environment's existing infrastructures (e.g., a home's water, electrical, and HVAC infrastructures). This paper presents HydroSense, a low-cost and easily-installed single-point sensor of pressure within a home's water infrastructure. HydroSense supports both identification of activity at individual water fixtures within a home (e.g., a particular toilet, a kitchen sink, a particular shower) as well as estimation of the amount of water being used at each fixture. We evaluate our approach using data collected in ten homes. Our algorithms successfully identify fixture events with 97.9% aggregate accuracy and can estimate water usage with error rates that are comparable to empirical studies of traditional utility-supplied water meters. Our results both validate our approach and provide a basis for future improvements.
Keywords: activity sensing, infrastructure-mediated sensing, water sensing
ViridiScope: design and implementation of a fine grained power monitoring system for homes BIBAKFull-Text 245-254
  Younghun Kim; Thomas Schmid; Zainul M. Charbiwala; Mani B. Srivastava
A key prerequisite for residential energy conservation is knowing when and where energy is being spent. Unfortunately, the current generation of energy reporting devices only provide partial and coarse grained information or require expensive professional installation. This limitation stems from the presumption that calculating per-appliance consumption requires per-appliance current measurements. However, since appliances typically emit measurable signals when they are consuming energy, we can estimate their consumption using indirect sensing. This paper presents ViridiScope, a fine-grained power monitoring system that furnishes users with an economical, self-calibrating tool that provides power consumption of virtually every appliance in the home. ViridiScope uses ambient signals from inexpensive sensors placed near appliances to estimate power consumption, thus no in-line sensor is necessary. We use a model-based machine learning algorithm that automates the sensor calibration process. Through experiments in a real house, we show that ViridiScope can estimate the end-point power consumption within 10% error.
Keywords: adaptive sensor calibration, machine learning, nonintrusive and spatially distributed sensing
It's not all about "Green": energy use in low-income communities BIBAKFull-Text 255-264
  Tawanna Dillahunt; Jennifer Mankoff; Eric Paulos; Susan Fussell
Personal energy consumption, specifically home energy consumption such as heating, cooling, and electricity, has been an important environmental and economic topic for decades. Despite the attention paid to this area, few researchers have specifically explored these issues within a community that makes up approximately 30% of U.S. households -- those below the federal poverty line. We present a study of 26 low-income households in two very different locations -- a small town in the Southern U.S. and a northerly metropolitan area. Through a photo-elicitation study and directed interviews, we explore the relationship between energy saving behaviors, external factors, and users' intrinsic values and beliefs. Most of our participants are committed to saving energy for non-financial reasons, even when not responsible for paying bills. Challenges to saving energy include safety and lack of control over the environment. We discuss how Ubicomp technologies for saving energy can address some of these challenges.
Keywords: domestic computing, low-income, sustainability
Experiences of participatory sensing in the wild BIBAKFull-Text 265-274
  Mark Paxton; Steve Benford
We present two studies of participatory sensing in the wild, in which groups of young people used sensors to collect environmental data along with contextual information such as photographs and written observations. These studies reveal how participants focused their attention on key events of interest, providing detailed information over a background of less carefully gathered automatic readings. Participants responded to events in their surroundings, sudden changes in sensor data, and recorded details relevant to the process of gathering the data itself. Based on these studies a framework is described, highlighting the negotiation of five activities in the experiences; planning, testing, navigation, capture and reflection.
Keywords: human-sensor dialogue, participatory sensing