Geomatric sensor computing environments

[Doyle Saylor <djsaylor@xxxxxxxxxxxxxx>]

Hello All,
I think this article on the developmental potential of geometric content for
computing is interesting.  I think geometric computing, making information
with spatial meaning, hasn't been well developed by capitalism.  Maps,
street signs, cultural information based upon location suggest how this has
developed in the past.  Big business likes this a lot.
thanks,
Doyle


Industry Outlook

The Smart Sensor Web

A Revolutionary Leap in Earth Observation

By Vincent Tao

Tao is the Canada research chair in Geomatics and the founding director of
Geospatial Information and Communication Technology (GeoICT) Lab, York
University, Toronto; e-mail: tao@xxxxxxxx

THE MOST PROFOUND REVOLUTIONARY TECHNOLOGIES ARE THOSE THAT DISAPPEAR. THEY
WEAVE THEMSELVES INTO THE FABRIC OF EVERYDAY LIFE UNTIL THEY'RE
INDISTINGUISHABLE. THE WEB IS AN EXCELLENT EXAMPLE OF SUCH TECHNOLOGY--IT'S
NO LONGER EXCITING, BECAUSE IT HAS BECOME PART OF OUR LIFE.

However, Web-enabled technologies are continuously advancing, challenging
our vision and even our dreams. One exciting new Web-enabled vision is the
Sensor Web.

Electronic Skin

With the presence of cheaper, miniature and smart sensors; abundant fast and
ubiquitous computing devices; wireless and mobile communication networks;
and autonomous and intelligent software agents, the Sensor Web has become a
clear technological trend in geospatial data collection, fusion and
distribution. The Sensor Web is a Web-centric, open, interconnected,
intelligent and dynamic network of sensors that presents a new vision for
how we deploy sensors, collect data, and fuse and distribute information.

Neil Gross' article, "The Earth Will Don an Electronic Skin," (BusinessWeek,
Aug. 30, 1999; http://www.businessweek .com/1999/99_35/b3644024.htm)
provides a compelling explanation of the Sensor Web concept:

"In the next century, planet Earth will don an electronic skin. It will use
the Internet as a scaffold to support and transmit sensations. This skin is
already being stitched together. It consists of millions of embedded
electronic measuring devices: thermostats, pressure gauges, pollution
detectors, cameras, microphones, glucose sensors, EKGs,
electroencephalographs. These will probe and monitor cities and endangered
species; the atmosphere; our ships, highways and fleets of trucks; our
conversations; our bodies--even our dreams."

In short, the Sensor Web offers full-dimensional, full-scale and full-phase
sensing and monitoring of Earth at all levels: global, regional and local.
The Sensor Web is a revolutionary concept toward achieving collaborative,
coherent, consistent and consolidated sensor data collection, fusion and
distribution.

Such sensors include flood gauges, air-pollution monitors, stress gauges on
bridges, mobile heart monitors, Webcams and satellite-borne Earth imaging
devices. The Web is considered a "central computer" that connects enormous
computing resources. The Sensor Web can similarly be thought of as a "global
sensor" that connects all sensors or sensor databases.

Characteristics

The Sensor Web is an evolving concept with many different research efforts
working to define the possibilities. Examples of pioneering work include
sensor networks (National Science Foundation), sensor pods (NASA's Jet
Propulsion Laboratory), Smart Dust (University of California, Berkeley) and
integrated Earth sensing (Canadian Centre for Remote Sensing).

A conceptual framework describes the Sensor Web.

Inspired by significant advances in sensors, communication, computing and
positioning technologies, the Sensor Web is being developed by connecting
heterogeneous sensors or many proprietary sensor networks. To succeed, the
Sensor Web must be interoperable, intelligent, dynamic, flexible and
scalable.

Interoperable

The Sensor Web is achieved by connecting the distributed, dynamic and
heterogeneous in-situ and remote sensors to an open, interconnected
network--the Web. The Sensor Web is a universe of network-accessible
sensors, sensory data and information. Just like building a Web system,
developing the Sensor Web requires thorough and careful design of the system
hierarchy, registry, Internet Protocol domain services and applications.
Implementation of interoperability requires commonly accepted standards and
specifications, and the Open GIS Consortium http://www.opengis.org has
pioneered much of this activity.

Intelligent

A unique characteristic of the Sensor Web is that the sensors deployed are
intelligent. They act as smart agents able to sense the environment in a
responsive and timely manner. They also can "communicate" to each other to
perform collaborative and integrated sensing.

Such intelligence comes from sensor connectivity, just like human
intelligence comes from connected neurons in the brain. Sensor networks
forage for information the way ants forage for food. By linking existing
databases or previously sensed data with the Sensor Web, we will
dramatically increase the efficiency and performance of sensing, monitoring
and change detection.

Dynamic

Thanks to wireless communication and real-time positioning technologies,
sensors no longer need to be fixed at a certain location. By removing
physical constraints, sensors can be mobile, placed anywhere or even be
"seeded" for large-area monitoring. As sensors are "position aware," their
location and movement can be tracked continuously via wireless networks.

Flexible

The Sensor Web consists of a large array of heterogeneous sensors that
monitor various phenomena and communicate data via different means. In
general, there are three basic modes of data transmission: deterministic,
triggered and on-demand.


A sensor pod prototype (inset) developed by NASA's Jet Propulsion Laboratory
can be massively seeded in any environment and configured in a network in
which pods can commun-icate to each other, and the accumu-lated data can be
transferred to the Internet.
Deterministic sensor platforms output data at a known time (for example,
once per second as in Global Positioning System (GPS) units). Triggered
sensors output data only when a predefined event is detected (e.g., thermal
pipeline-leak detector). On-demand sensors can control data transmission in
real time or near real time when data transmission is requested from
clients. The key to making the sensor network intelligent and different from
other sensor systems is the integration of sensor types in a flexible
manner.

Scalable

The Sensor Web is intended to offer massive sensing by interconnecting a
large array of sensors. Therefore, the Sensor Web must not be inherently
restricted to contain a specific number of nodes or operate within a
predefined area.

Several enabling and emerging technologies support the Sensor Web's
development.

The primary nodes could be located anywhere in the network, and multiple
sub-nodes deployed in a given area would mesh with one another. The Sensor
Web can be regarded as one instrument with a massive sensing capability.
Flexibly adding or replacing sensors in the network provides a great ability
for fault tolerance.

Enabling Technologies

The Sensor Web's revolutionary aspect lies in its advanced integration of
many "state-of-the-art" enabling technologies--mainly sensor, wireless
communication, positioning, tracking and information technologies.

Sensor research has been undergoing a quiet revolution, promising to have
significant impact on a broad range of applications. So far, more than 100
physical (e.g., light, pressure, humidity), chemical (e.g., gas, liquid,
solid) and biological (e.g., DNA, protein) properties can be sensed by using
in-situ technology. Sensors reside on Earth--on the oceans and in the
air--and in space, providing a multi-level picture of Earth phenomena.

Typically, sensors fall into one of two basic categories: in-situ sensors
measuring physical properties within the area immediately surrounding a
sensor or remote sensors measuring properties (typically via radiation
reflected or emitted from an observed object) at some distance from a
sensor. With the Sensor Web concept, such distinction is disappearing.
Sensors are becoming smaller, cheaper, lighter and require less power to
run. Thus, they can be mounted or placed on any platform.

Given the recent advances of microelectronic and micro electromechanical
technology, sensors can be made smaller, cheaper and lighter. For example,
inside a walnut-sized sensor pod can reside a rugged combination of minute
instruments on microchips each programmed to collect a different
measurement, such as temperature, humidity or air pressure.

The pods can be massively seeded in any environment and configured in a
network in which pods can communicate with each other, and the accumulated
data can be transferred to the Internet. The cheap and small sensors could
be made as redundant and/or dense as desired by distributing many pods over
a target area. New sensor pods could be seeded to replace old ones.
Redundancy would render the Sensor Web tolerant to failures of individual
pods.

An architecture for open Sensor Web services is being developed at York
University's GeoICT Lab.

Having sensors everywhere is of limited value unless the sensory data and
information can be accessed and distributed to end users in an easy, timely
and low-cost manner. Wireless communication and ubiquitous computing
technologies are enabling such connections. Due to wide use of wireless
protocols like Bluetooth, 802.11a and 802.11b, and the adoption of 2.5GHz
and 3GHz high-bandwidth mobile technology, a globally interconnected
wireless communication network is just around the corner.

Location is an essential component of the Sensor Web. When and where sensor
data is observed is of equal value to the sensor data itself. There are wide
options to integrate positioning technologies (e.g., GPS, A-GPS, Internet
GPS, radio-frequency identification, real-time locating system, cellular
network positioning, etc.) with sensor networks. There are important
research topics in location-based routing of sensors as well as optimized
sensor network topology and configuration.

Open Sensor Web Services

There are many technical issues involved in building the Sensor Web
framework. From a system architecture viewpoint, the Sensor Web involves the
following layers:

·       Sensor layer--sensor design, materials, miniaturization, energy
consumption, etc.
·       Communication layer--networking, protocol, topology, etc.
·       Location layer--locating, routing, addressing, etc.
·       Information layer--agents, management, fusion, distribution, etc.

Depending on the properties of sensors, geographic coverage, network access
capabilities and, more importantly, domain applications, the physical
architecture (i.e., the first three layers) can be very different. The
information layer serves as a backbone and shares a commonality. This layer
is a gateway to integrate and fuse observations from spatially referenced
sensors. It connects widely distributed in-situ sensors and remote sensors
over wired or wireless networks. Interoperability becomes a key to enable
the information layer's integration capability.

Within the broader context of Web Services, OGC has taken a leadership role
in developing and building a unique and revolutionary open platform for
exploiting Web-connected sensors. OGC's goal is to make all types of
Web-resident sensors, instruments and imaging devices as well as
repositories of sensor data discoverable, accessible and, where applicable,
controllable via the Web. OGC's open sensor Web service consists of three
elements:

1. SensorML provides information model and encodings for discovering,
querying and controlling Web-resident sensors. SensorML establishes a
standard schema for metadata describing sensors, sensor platforms and
sensor-tasking interfaces (see http://www.opengis.org/info/discussion.htm

1. The Sensor Collection Service (SCS) fetches observations from a sensor or
constellation of sensors. This is the inter- mediary between a client and an
observation repository or near-real-time sensor channel. Clients
implementing SCS also can obtain information that describes the associated
sensors and platforms.

3. A sensor registry provides information about the available SCS using
SensorML, providing discovery, catalog and index services to clients.

An architecture for open Sensor Web services is being developed at York
University's GeoICT Lab http://sensorweb.geoict.net. The system is built on
the GeoServNet technology, a 2-D/3-D/n-D Java Web GIS, and can be openly
deployed to accommodate virtually any sensor or sensor networks.

The Sensor Web presents endless opportunities for adding a sensory dimension
to the Web's globe-encircling virtual nervous system. This has extraordinary
significance for science, environmental monitoring, transportation
management, public safety, homeland security, defense, disaster management,
health and many other domains of activity.

The fundamental revolution in the Sensor Web vision lies in its
interoperable, intelligent, dynamic, flexible and scalable "connectivity."
It's an evolving framework enabled by many emerging technologies. Our
understanding of the Sensor Web is in its infancy, like the Web 10 year ago,
and it's only a matter of time before the Sensor Web joins the fabric of our
lives and becomes indistinguishable.

Author's Note: I'd like to thank Steve Liang for his help in preparing this
article.