%M C.UBICOMP.09.1
%T From spaces to places: emerging contexts in mobile privacy
%S Places & location
%A Mancini, Clara
%A Thomas, Keerthi
%A Rogers, Yvonne
%A Price, Blaine A.
%A Jedrzejczyk, Lukazs
%A Bandara, Arosha K.
%A Joinson, Adam N.
%A Nuseibeh, Bashar
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 1-10
%K context, contextual interview, experience sampling, facebook, memory phrase,
mobile privacy, place
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620547
%X 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.

%M C.UBICOMP.09.11
%T The commodification of location: dynamics of power in location-based systems
%S Places & location
%A Shklovski, Irina
%A Vertesi, Janet
%A Troshynski, Emily
%A Dourish, Paul
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 11-20
%K discipline, gps, power, surveillance
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620548
%X 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.

%M C.UBICOMP.09.21
%T Discovering semantically meaningful places from pervasive RF-beacons
%S Places & location
%A Kim, Donnie H.
%A Hightower, Jeffrey
%A Govindan, Ramesh
%A Estrin, Deborah
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 21-30
%K beacon traces, location, place learning
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620549
%X 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.

%M C.UBICOMP.09.31
%T Privately querying location-based services with SybilQuery
%S Places & location
%A Shankar, Pravin
%A Ganapathy, Vinod
%A Iftode, Liviu
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 31-40
%K anonymity, location-based services, privacy, vehicular computing
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620550
%X 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.

%M C.UBICOMP.09.41
%T Eye movement analysis for activity recognition
%S Activity recognition
%A Bulling, Andreas
%A Ward, Jamie A.
%A Gellersen, Hans
%A Tröster, Gerhard
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 41-50
%K activity recognition, electrooculography (eog), eye movement analysis,
wearable computing
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620552
%X 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.

%M C.UBICOMP.09.51
%T Recognizing daily activities with RFID-based sensors
%S Activity recognition
%A Buettner, Michael
%A Prasad, Richa
%A Philipose, Matthai
%A Wetherall, David
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 51-60
%K activity detection, rfid, sensor networks, wisp
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620553
%X 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.

%M C.UBICOMP.09.61
%T Cross-domain activity recognition
%S Activity recognition
%A Zheng, Vincent Wenchen
%A Hu, Derek Hao
%A Yang, Qiang
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 61-70
%K activity recognition, cross domain, transfer learning, web search
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620554
%X 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.

%M C.UBICOMP.09.71
%T Recognizing stereotypical motor movements in the laboratory and classroom: a
case study with children on the autism spectrum
%S Activity recognition
%A Albinali, Fahd
%A Goodwin, Matthew S.
%A Intille, Stephen S.
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 71-80
%K accelerometers, activity recognition, autism
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620555
%X 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.

%M C.UBICOMP.09.81
%T inAir: measuring and visualizing indoor air quality
%S Notes
%A Kim, Sunyoung
%A Paulos, Eric
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 81-84
%K air quality, domestic computing, health, sustainability
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620557
%X 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.

%M C.UBICOMP.09.85
%T Wearable therapist: sensing garments for supporting children improve posture
%S Notes
%A Harms, Holger
%A Amft, Oliver
%A Tröster, Gerhard
%A Appert, Mirjam
%A Müller, Roland
%A Meyer-Heim, Andreas
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 85-88
%K back posture, rehabilitation, smart garments, smash
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620558
%X 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.

%M C.UBICOMP.09.89
%T Sonar-based measurement of user presence and attention
%S Notes
%A Tarzia, Stephen P.
%A Dick, Robert P.
%A Dinda, Peter A.
%A Memik, Gokhan
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 89-92
%K attention, presence, sonar, ultrasonics, user study
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620559
%X 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.

%M C.UBICOMP.09.93
%T Simultaneous localization and mapping for pedestrians using only
foot-mounted inertial sensors
%S Notes
%A Robertson, Patrick
%A Angermann, Michael
%A Krach, Bernhard
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 93-96
%K ins-based positioning, odometry, indoor positioning, pedestrian navigation,
simultaneous localization and mapping
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620560
%X 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.

%M C.UBICOMP.09.97
%T BlueTone: a framework for interacting with public displays using dual-tone
multi-frequency through bluetooth
%S Notes
%A Dearman, David
%A Truong, Khai N.
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 97-100
%K at a distance interaction, bluetone, bluetooth, public display
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620561
%X 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.

%M C.UBICOMP.09.101
%T Toward emergent technology for blended public displays
%S Notes
%A Chandler, Angie
%A Finney, Joe
%A Lewis, Carl
%A Dix, Alan
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 101-104
%K emergent, field trial, firefly, public display, self-organizing
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620562
%X 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.

%M C.UBICOMP.09.105
%T A spotlight on security and privacy risks with future household robots:
attacks and lessons
%S Security & access
%A Denning, Tamara
%A Matuszek, Cynthia
%A Koscher, Karl
%A Smith, Joshua R.
%A Kohno, Tadayoshi
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 105-114
%K cyber-physical systems, domestic robots, household robots, multi-robot
attack, privacy, robots, security, single-robot attack, ubiquitous robots
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620564
%X 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.

%M C.UBICOMP.09.115
%T Authenticating ubiquitous services: a study of wireless hotspot access
%S Security & access
%A Kindberg, Tim
%A Bevan, Chris
%A O'Neill, Eamonn
%A Mitchell, James
%A Grimmett, Jim
%A Woodgate, Dawn
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 115-124
%K authentication, phishing, ubiquitous services, wi-fi
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620565
%X 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.

%M C.UBICOMP.09.125
%T SessionMagnifier: a simple approach to secure and convenient kiosk browsing
%S Security & access
%A Yue, Chuan
%A Wang, Haining
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 125-134
%K ajax, kiosk, mobile device, security, usability, web browsing
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620566
%X 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.

%M C.UBICOMP.09.135
%T Understanding file access mechanisms for embedded Ubicomp collaboration
interfaces
%S Security & access
%A Collins, Anthony
%A Bezerianos, Anastasia
%A McEwan, Gregor
%A Rittenbruch, Markus
%A Wasinger, Rainer
%A Kay, Judy
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 135-144
%K file system ui, single display groupware, tabletop interface
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620567
%X 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.

%M C.UBICOMP.09.145
%T Broadening Ubicomp's vision: an exploratory study of charismatic
pentecostals and technology use in Brazil
%S UbiComp worldwide
%A Wyche, Susan P.
%A Magnus, Camila M.
%A Grinter, Rebecca E.
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 145-154
%K hci4d, religious technology, user experience
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620569
%X 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.

%M C.UBICOMP.09.155
%T Ubicomp4D: infrastructure and interaction for international development --
the case of urban indian slums
%S UbiComp worldwide
%A Sambasivan, Nithya
%A Rangaswamy, Nimmi
%A Cutrell, Ed
%A Nardi, Bonnie
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 155-164
%K ict4d, india, low-income communities, mobile technologies, privacy, trust,
ubicomp4d, urban slums
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620570
%X 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.

%M C.UBICOMP.09.165
%T Encountering SenseCam: personal recording technologies in everyday life
%S UbiComp worldwide
%A Nguyen, David H.
%A Marcu, Gabriela
%A Hayes, Gillian R.
%A Truong, Khai N.
%A Scott, James
%A Langheinrich, Marc
%A Roduner, Christof
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 165-174
%K experience sampling, paratyping, privacy, sensecam
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620571
%X 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.

%M C.UBICOMP.09.175
%T Applying pervasive technologies to create economic incentives that alter
consumer behavior
%S Behavior change
%A Yamabe, Tetsuo
%A Lehdonvirta, Vili
%A Ito, Hitoshi
%A Soma, Hayuru
%A Kimura, Hiroaki
%A Nakajima, Tatsuo
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 175-184
%K activity-based micro-pricing, economic incentives, micropayments, mobile
payment, persuasive technology, virtual currency
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620573
%X 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.

%M C.UBICOMP.09.185
%T Playful bottle: a mobile social persuasion system to motivate healthy water
intake
%S Behavior change
%A Chiu, Meng-Chieh
%A Chang, Shih-Ping
%A Chang, Yu-Chen
%A Chu, Hao-Hua
%A Chen, Cheryl Chia-Hui
%A Hsiao, Fei-Hsiu
%A Ko, Ju-Chun
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 185-194
%K hydration behavior, mobile computing, persuasive technology, ubiquitous
computing
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620574
%X 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.

%M C.UBICOMP.09.195
%T Assessing demand for intelligibility in context-aware applications
%S Context-aware & wearable systems
%A Lim, Brian Y.
%A Dey, Anind K.
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 195-204
%K context-aware, explanations, intelligibility, satisfaction
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620576
%X 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.

%M C.UBICOMP.09.205
%T Interactive dirt: increasing mobile work performance with a wearable
projector-camera system
%S Context-aware & wearable systems
%A McFarlane, Daniel C.
%A Wilder, Steven M.
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 205-214
%K mobile computing, projector-camera system, situational impairment, wearable
user interface
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620577
%X 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.

%M C.UBICOMP.09.215
%T SwimMaster: a wearable assistant for swimmer
%S Context-aware & wearable systems
%A Bächlin, Marc
%A Förster, Kilian
%A Tröster, Gerhard
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 215-224
%K context recognition, feedback, performance evaluation, swimming, wearable
system
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620578
%X 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.

%M C.UBICOMP.09.225
%T Validated caloric expenditure estimation using a single body-worn sensor
%S Context-aware & wearable systems
%A Lester, Jonathan
%A Hartung, Carl
%A Pina, Laura
%A Libby, Ryan
%A Borriello, Gaetano
%A Duncan, Glen
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 225-234
%K caloric balance, long term health monitoring, pervasive health, wellness
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620579
%X 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.

%M C.UBICOMP.09.235
%T HydroSense: infrastructure-mediated single-point sensing of whole-home water
activity
%S Sensing & sustainability
%A Froehlich, Jon E.
%A Larson, Eric
%A Campbell, Tim
%A Haggerty, Conor
%A Fogarty, James
%A Patel, Shwetak N.
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 235-244
%K activity sensing, infrastructure-mediated sensing, water sensing
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620581
%X 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.

%M C.UBICOMP.09.245
%T ViridiScope: design and implementation of a fine grained power monitoring
system for homes
%S Sensing & sustainability
%A Kim, Younghun
%A Schmid, Thomas
%A Charbiwala, Zainul M.
%A Srivastava, Mani B.
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 245-254
%K adaptive sensor calibration, machine learning, nonintrusive and spatially
distributed sensing
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620582
%X 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.

%M C.UBICOMP.09.255
%T It's not all about "Green": energy use in low-income communities
%S Sensing & sustainability
%A Dillahunt, Tawanna
%A Mankoff, Jennifer
%A Paulos, Eric
%A Fussell, Susan
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 255-264
%K domestic computing, low-income, sustainability
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620583
%X 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.

%M C.UBICOMP.09.265
%T Experiences of participatory sensing in the wild
%S Sensing & sustainability
%A Paxton, Mark
%A Benford, Steve
%B Proceedings of the 2009 International Conference on Uniquitous Computing
%D 2009
%P 265-274
%K human-sensor dialogue, participatory sensing
%* (c) Copyright 2009 ACM
%W http://doi.acm.org/10.1145/1620545.1620584
%X 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.