Great Duck Island Requirements

• Internet access
  The sensor networks at GDI must be accessible via the
  Internet. An essential aspect of habitat monitoring applications
  is the ability to support remote interactions with
  in-situ networks.
• Hierarchical network
  The field station at GDI needs sufficient resources to host
  Internet connectivity and database systems. However, the
  habitats of scientific interest are located up to several kilometers
  further away. A second tier of wireless networking
  provides connectivity to multiple patches of sensor networks
  deployed at each of the areas of interest. Three to four
  patches of 100 static (not mobile) nodes is sufficient to start.
• Sensor network longevity
  Sensor networks that run for 9 months from non-rechargeable
  power sources would have significant audiences today. Although
  ecological studies at GDI span multiple field seasons,
  individual field seasons typically vary from 9 to 12 months.
  Seasonal changes as well as the plants and animals of interest
  determine their durations.
• Operating offthegrid
  Every level of the network must operate with bounded energy
  supplies. Although renewable energy, for example solar
  power, may be available at some locations, disconnected operation
  remains a possibility. GDI has sufficient solar power
  to run many elements of the application 24x7 with low probabilities
  of service interruptions due to power loss.
• Management atadistance
  The remoteness of the field sites requires the ability to
  monitor and manage sensor networks over the Internet. Although
  personnel may be on site for a few months each summer,
  the goal is zero on-site presence for maintenance and
  administration during the field season, except for installation
  and removal of nodes.
• Inconspicuous operation
  Habitat monitoring infrastructure must be inconspicuous.
  It should not disrupt the natural processes or behaviors under
  study. Removing human presence from the study areas
  both eliminates a source of error and variation in data collection,
  as well as a significant source of disturbance.
• System behavior
  From both a systems and end-user perspective, it is critical
  that sensor networks exhibit stable, predictable, and repeatable
  behavior whenever possible. An unpredictable system
  is difficult to debug and maintain. More importantly,
  predictability is essential in developing trust in these new
  technologies for life scientists.
• Insitu interactions
  Although the majority of interactions with the sensor networks
  are expected to be via the Internet, local interactions
  are required during initial deployment, during maintenance
  tasks, as well as during on-site visits. PDAs serve an important
  role in assisting with these tasks. They may directly
  query a sensor, adjust operational parameters, or simply assist
  in locating devices.
• Sensors and sampling
  For our particular applications, the ability to sense light,
  temperature, infrared, relative humidity, and barometric pressure
  provide an essential set of useful measurements. The
  ability to sense additional phenomena, such as acceleration/
  vibration, weight, chemical vapors, gas concentrations,
  pH, and noise levels would augment them.
• Data archiving
  Archiving sensor readings for off-line data mining and
  analysis is essential. The reliable offloading of sensor logs to
  databases in the wired, powered infrastructure is an essential
  capability. The desire to interactively “drill-down” and explore
  individual sensors, or a subset of sensors, in near realtime
  complement log-based studies. In this mode of opera-

Figure 1: System architecture for habitat monitoring
tion, the timely delivery of fresh sensor data is key. Lastly,
nodal data summaries and periodic health-and-status monitoring
requires timely delivery.