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Research Project

Urban Sensing

Technology > Systems > Urban Sensing

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Urban Sensing systems research is a collaboration between CENS and the Center for Research in Engineering, Media and Performance (REMAP) that seeks to develop cultural and technological approaches for using embedded and mobile sensing to invigorate public space and enhance civic life.

Unlike scientific applications, many sensors for urban applications are already ‘out there,’ watching and listening. Mobile phones provide us with sounds and imagery from our homes and neighborhoods, and the near ubiquity of wireless access in many future urban settings will allow us to publish or share data easily, immediately. Soon private citizens will have access to a great diversity of sensors, allowing them to make even more detailed observations of their communities. They will be able to cross-reference spatially and temporally tagged data they gather with publicly available data from private and municipal monitoring of the city—traffic, weather, air quality, pedestrian flow—the environment and rhythms of urban life.

At the edges of culture, lightweight web applications, built on this publicly available information and free web services, emerge already almost daily to explore new linkages among these varied data. Expanding on their approach, we are exploring how these intermittent georeferenced media records of everyday life can be coordinated to achieve ‘distributed documentation’ of the urban environment, as well as be fused with other sensed data about the city and fed back into the physical, collective experience in urban public spaces.  Unlike scientific applications, the hardware is not owned and managed by a small number of central authorities. Citizens carry sensors and contribute data voluntarily. A single entity does not pose interesting ‘hypotheses,’ design experiments, force participation. Instead, the process of learning from an urban environment can be organic and decentralized, existing more in the realm of social networking software. However, the power of this network still comes from our ability to verify the context of shared data, to actuate (to filter, identify and respond to events); to aggregate data in space and time; and to allow individuals to coordinate activities.


We are developing the network architecture required for such applications to flourish, as well as corresponding driver applications and testbeds. The architecture includes the low-level capabilities necessary to verify location, aggregate sources, control resolution and implement privacy policies, all for data originating from sensors in the physical world:

  1. In-network verification of location and time context.

Location and time are key elements of context that can be attested to by the network itself. Essential to building space-time semantics into the network fabric is the ability for the network to verifiably measure location and time of a device when it injects a packet into the network.

  1. Provisions for operating on physical context based on sensor readings.

Additionally, the physical context of sensor data is richer than just location and time. It includes, for example, the orientation of the sensor, measurement made by other sensing modalities, and measurements made by other sensors in the vicinity. The role of the network in this case is therefore one of calculating and verifying the context according to application specified rules. (Unlike location and time, it cannot intrinsically verify these measurements.)

  1. Resolution control of data publishing, enabling selective sharing of information.

The final aspect of context verification is the ability for the source of data to exercise control over what is revealed to a subscriber. The publisher may not wish to reveal too much of the context so as to preserve a desired level of anonymity. For example, the network may know the location of a node to a few meters but the subscriber may only be willing to share the location information to the zip code level. Likewise, a sensor may be willing to share information only as part of an aggregate in a geographical region. The edges of the proposed architecture must be capable of deliberately reducing the fidelity of the context information it measures (location, time) or derives from sensor values, and it must do so differently for different subscribers.

  1. Services for naming, dissemination and aggregation.

The combination of physical and personal coupling enabled by personal wireless sensing devices introduces new naming, dissemination, and aggregation requirements and constraints. In particular, personal physical sensing demands fine grain articulation of selective sharing—the dissemination not just of the data and context information, but the policies describing the resolution control required. We suggest that urban and social sensing applications will flourish only given a flexible sensor information fabric that allows a wide range of data remixing, correlation and fusion applications.


  1. CENS / REMAP Urban Sensing Summit, Bradley International Center, May 4, 2006.
  2. Ubicity Workshop at Ubicomp, September 17-21, 2006. Call for Papers –


Faculty: Jeff Burke (Theater, Film and Television), Dana Cuff (Architecture & Urban Design), Deborah Estrin (Computer Science), Mark Hansen (Statistics), Jerry Kang (Law), William Kaiser (Electrical Engineering), Mani Srivastava (Electrical Engineering), Fabian Wagmister (Film, Television and Digital Media)

Graduate Students: August Joki (Computer Science), Martin Lukac (Computer Science),  Andrew Parker (Computer Science), Christopher Mar (Computer Science), Jeff Mascia (Computer Science), Sasank Reddy (Electrical Engineering), Thomas Schmid (Electrical Engineering)


Sensor Planet: a Nokia-initiated cooperation
Cisco: Application Oriented Networking
Walt Disney Imagineering Research and Development, Inc.


J. Burke, D. Estrin, M. Hansen, A. Parker, N. Ramanathan, S. Reddy, M. B. Srivastava. "Participatory sensing." World Sensor Web Workshop, ACM Sensys 2006, Boulder, Colorado, 2006. file (pdf)

Mani Srivastava, Mark Hansen, Jeff Burke, Andrew Parker, Sasank Reddy, Ganeriwal Saurabh, Mark Allman, Vern Paxson, Deborah Estrin. Wireless Urban Sensing Systems, CENS Technical Report #65 (pdf), April 2006.