Please refer to the UW Ubicomp Lab webpage for a more recent list of projects.
My research interests are in the area of mobile and ubiquitous computing. I am currently interested in creating new sensing techniques to develop low-cost and easy-to-deploy location and sensing technologies to support a variety of applications. Most of my sensing work has been to support studies of human activity in natural settings. I am also interested in novel interaction techniques for mobile devices.
PowerLine Positioning
Video:
PowerLine Positioning (PLP) is an inexpensive technique that uses fingerprinting of multiple signals transmitted along the powerline to achieve subroom- level localization. Custom tags detect these signal and determine its location.
Patel, S.N., K.N. Truong, and G.D. Abowd. PowerLine Positioning: A Practical Sub-Room-Level Indoor Location System for Domestic Use.Proceedings of Ubicomp 2006. [pdf]
Patel, S. N. Supporting Location and Proximity-Based Studies in Natural Settings. Adjunct Proceedings of Pervasive 2007.
Activity sensing in the home has a variety of important applications, including healthcare, entertainment, home automation, energy monitoring and post-occupancy research studies. Many existing systems for detecting occupant activity require large numbers of sensors, invasive vision systems, or extensive installation procedures. We present an approach that uses a single plug-in sensor to detect a variety of electrical events throughout the home. This sensor detects the electrical noise on residential power lines created by the abrupt switching of electrical devices and the noise created by certain devices while in operation. We use machine learning techniques to recognize electrically noisy events such as turning on or off a particular light switch, a television set, or an electric stove. We tested our system in one home for several weeks and in five homes for one week each to evaluate the system performance over time and in different types of houses. Results indicate that we can learn and classify various electrical events with accuracies ranging from 85-90%.
Patel, S.N., Robertson, T., Kientz, J.A., Reynolds, M.S., Abowd, G.D. At the Flick of a Switch: Detecting and Classifying Unique Electrical Events on the Residential Power Line.Proceedings of Ubicomp 2007.[pdf] Received Best Paper Award and Best Presentation Award.
Press:
Tech professor designing camera cloak. Justin Rubner. Atlanta Business Chronicle. June 15, 2007.
'Smart homes' could track your electrical noise. Kurt Kleine. New Scientist. September 10, 2007.
Electrical Noise Could Help Automate Your Home. Darren Murph. Engadget. September 12, 2007. Engadget link.
Thinking about Ubiquitous Technology. Sonja Prieth. Austrian National Radio. September 19, 2007.
Human Movement Detection via Pressure Sensing in HVAC Systems
We have developed an approach for whole-house gross movement and room transition detection through sensing at only one point in the home. We consider this system to be one member of an important new class of human activity monitoring approaches based on what we call infrastructure mediated sensing, or "home bus snooping." Our solution leverages the existing ductwork infrastructure of central heating, ventilation, and air conditioning (HVAC) systems found in many homes. Disruptions in airflow, caused by human inter-room movement, result in static pressure changes in the HVAC air handler unit. This is particularly apparent for room-to-room transitions and door open/close events involving full or partial blockage of doorways and thresholds. We detect and record this pressure variation from sensors mounted on the air filter and classify where certain movement events are occurring in the house, such as an adult walking through a particular doorway or the opening and closing of a particular door. In contrast to more complex distributed sensing approaches for motion detection in the home, our method requires the installation of only a single sensing unit (i.e., an instrumented air filter) connected to an embedded or personal computer that performs the classification function.
Patel, S.N., Reynolds, M.S., Abowd, G.D. Detecting Human Movement by Differential Air Pressure Sensing in HVAC System Ductwork: An Exploration in Infrastructure Mediated Sensing.To appear in the Proceedings of Pervasive 2008. [pdf]Received Best Paper Award
Press:
Adapted aircon can track movement in the home. Colin Barras. New Scientist. May 16, 2008.
TrackSense: Infrastructure-free Localization
While commercial solutions for precise indoor positioning exist, they are costly and require installation of additional infrastructure, which limits opportunities for widespread adoption. We have developed a self-contained solution to precise indoor positioning that requires no additional environmental infrastructure. Evaluation of our prototype indicates that such a system can deliver up to 4 cm accuracy with 3 cm precision in rooms up to five meters squared, as well as 2 degree accuracy and 1 degree precision on orientation.
Koehler, M., Patel, S.N., Summet, J.W., Stuntebeck, E.P., Abowd, G.D. TrackSense: Infrastructure Free Precise Indoor Positioning using Projected Patterns.Proceedings of Pervasive 2007.[pdf]
BLUI: Low-Cost Blowable User Interfaces
Video:
We describe a unique form of hands-free interaction that can be implemented on most commodity computing plat-forms. Our approach supports blowing at a laptop or com-puter screen to directly control certain interactive applica-tions. Localization estimates are produced in real-time to determine where on the screen the person is blowing. Our approach relies solely on a single microphone, such as those already embedded in a standard laptop or one placed near a computer monitor, which makes our approach very cost-effective and easy-to-deploy. We show example inter-action techniques that leverage this approach.
Patel, S.N. and Abowd, G.D. BLUI: Low-cost Localized Blowable User Interfaces. Proceedings of UIST 2007. [pdf]
Press:
Georgia Tech researchers demonstrate blowable user interface. Darren Murph. Engadget. November 15, 2007. Engadget link
New computer interface: Blow on the screen. Stephen Shankland. CNET News. November 14, 2007. News.com link
iCam: At-a-distance Interaction
Video:
Effective integration of sensing and laser-assisted interaction have resulted in a handheld device, the iCam, which simultaneously calculates its own location as well as the location of another object in the environment. iCam demonstrates how location-aware, at-a-distance interaction simplifies certain location-aware activities. This work was done in Tokyo, Japan at Sony CSL with Jun Rekimoto..
Patel, S.N., Rekimoto, J., and Abowd, G.D. iCam: Precise at-a-distance Interaction in the Physical Environment. Proceedings of Pervasive 2006.[pdf]Nominated for Best Paper.
Studying the Proximity of Mobile Devices to Users
Many Ubicomp and mobile applications being developed assume users alway have their phones nearby, but we suspect that this may not always be true. Thus, we are empirically studying the proximity of users to mobile devices to determine people's usage of mobile phones.
Patel, S.N., J.A. Kientz, G.R. Hayes, S. Bhat, and G.D. Abowd. Farther Than You May Think: An Empirical Investigation of the Proximity of Users to their Mobile Phones. Proceedings of Ubicomp 2006. [pdf]
Capture Resistant Environment: Blocking the Recording of Cameras
Video:
The Capture Resistant Environment uses cameras and projectors to prevent unauthorized photography and video recording. The camera can detect the lens of a digital camera and the projected light can neutralize the camera, making any images or video recordings blurred and thus useless.
Truong, K.N., Patel, S.N., Summet, J.W., and Abowd, G.D. Preventing Camera Recording by Designing a Capture-Resistant Environment. Proceedings of Ubicomp 2005.[pdf]
Patel, S.N., Summet, J.W., Truong, K.N. BlindSpot: Creating Capture-Resistant Spaces. Protecting Privacy in Video Surveillance. Ed. Andrew Senior. To Appear. 2008.
US PATENT PENDING (062012 1090/3588PR) 2005.
Press:
NY Times, Top Ideas of the Year. Berzon, A. The Anti-Paparazzi Flash. N.Y. Times Magazine, The 5th Annual Year in Ideas Issue. December 11, 2005, p. 60.
White light blinds film pirates. BBC News, June 20, 2006. Eng, P.
Tech Students Devise a Way to Block Prying Eyes. ABC News. September 20, 2005. Kanellos, M.
Crave Privacy? New Tech Knocks Out Digital Cameras. CNET News. September 19, 2005. Biever, C.
Illicit Snappers Caught Infrared Handed. New Scientist, Issue 2515. September 3, 2005, p. 24.
Security aid blinds phone cameras. A.L. Narayan. Laser, optics and phontonics resources and new. Oct 3, 2005.
DominInc. Science News, July, 170(1), p.14.
Tech professor designing camera cloak. Justin Rubner. Atlanta Business Chronicle. June 15, 2007.
Personal Audio Loop
With frequent changes in the topics of discussion or other interruptions, sometimes it is difficult to resume a previous thread in a conversation, even if it occurred only minutes ago. The Personal Audio Loop (PAL) application is a near-term audio recording system to support the recovery of interrupted conversations.
Patel, S.N., Truong, K.N., Hayes, G.R., Iachello, G., Kienta, J.A., Abowd, G.D. The Personal Audio Loop: A Ubiquitous Audio-Based Memory Aid. Book Chpater in the Handbook of Research on User Interface Design and Evaluation for Mobile Technology. 2008.
Abowd, G.D., Hayes, G.R., Iachello, G., Kientz, J.A., Patel, S.N., Stevens, M., Truong, K.N. Prototypes and Paratypes: Mixed Methods for Designing Mobile and Ubiquitous Computing Applications, IEEE Pervasive Computing Magazine, 4(4), IEEE Press, 67.73. [pdf]
Hayes, G.R., Patel, S.N., Truong, K.N., Iachello, G., Kientz, J.A., Farmer, R., Abowd, G.D. The Personal Audio Loop: Designing a Ubiquitous Audio-Based Memory Aid.Proceedings of Mobile HCI 2004.[pdf]
FETCH
FETCH is a mobile system for aiding the visually impaired in locating their misplaced objects in many locations. Through a focus group and individual interviews with the visually impaired, we discovered a need for a quick, temporary tagging system for frequently lost objects that can be used in many locations. We deployed this system with 4 users in visual impariments on a mobile phone using Bluetooth tags.
Kientz, J.A., S.N. Patel, A.T. Tyebkhan, B. Gane, J. Wiley, and G.D. Abowd. Where?s My Stuff? Design and Evaluation of a Mobile System for Locating Lost Items for the Visually Impaired. Proceedings of ASSETS 2006. [pdf]
Mobile Phone Interaction Techniques
I have worked on a variety of mobile phone interaction techniques. This includes ways to interact with the physical environment, gesture-based authentication, and pressure-based text input.
Patel, S.N., Pierce, J. and Abowd, G.D. A Gesture-based Authentication Scheme for Untrusted Public Terminals. Proceedings of UIST 2004.[pdf]
Clarkson, E.C., Patel, S. N., Pierce, J.S., Abowd, G.D. Exploring Continuous Pressure Input for Mobile Phones. GVU Tech Report. GIT-GVU-06-20. 2006. [pdf]
Patel, S.N., Kientz, J. A. and Zagal, J.P. LoCoL: Encouraging Social Interaction and Exploration Through a Distributed, Multi-Media, Location-Based Mobile Game.GVU Tech Report. 2004. [pdf]
Patel, S.N. and G.D. Abowd. A 2-way Laser-assisted Selection Scheme for Handhelds in a Physical Environment.Proceedings of Ubicomp 2003. [pdf]
Patel, S.N. and Abowd, G.D. Beyond Mobile Telephony: Exploring Opportunities for Applications on the Mobile Phone Handset. GVU Tech Report. August 2003. [pdf]
Press:
Georgia Tech develops gesture system for cellphone games. Engadget, Dec 7th. 2006
Family Video Archive and The Context Cam
The Family Video Archive helps in organizing and retrieving home videos. You can annotate video files with metadata and use this data to find the ones you are looking for. Includes work on the Context Cam for automatically annotating videos at the point of capture.
Patel, S.N. and Abowd, G.D. The ContextCam: Automated Point of Capture Video Annotation. In the Proceedings of Ubicomp 2004.[pdf]
