BIOSENSORS

The Expanding Technology:

Previously, environmental sensor networks would use a dedicated wiring system and operations panel; however, today, most companies use the relatively inexpensive Simple Network Management Protocol (SNMP) along with network and alerting software, which only requires an Ethernet link to the network and can be monitored like any other network device.

The Hardware:

Environmental monitors now have three basic components: a base unit, probes and a network connector. The base can be wall-mounted, rackmount,or able to sit on a shelf. There may be more than one sensor per unit along with several ports for external probes. In addition the units may “include a port for connecting to the network and have server software for remote configuration and graphing” (Robb 2003, “Making”).

Expense:

“But the environmental monitors do have one potential drawback. Each type of sensor, while potentially useful, adds to the price of the system and can lead an administrator to conclude that it is too expensive to install anything” (Robb 2003, “Making”).

“You have to decide which factors are most important to monitor,” says Marc Bilodeau, CTO for leading environmental sensor distributor Javica. “For example, it may be cool to have a camera, but what really matters is the temperature and humidity” (Robb 2003, “Making”).

Sensor Vocabulary:

ASIC:application-specific integrated circuit for telemetry, which is “automatic measurement and transmission of data from remote sources to receivers for recording and analysis” (Jacobson n.d.).
Attenuation: “absorption due to conversion of acoustic energy into heat, which increases with distance and frequency. It is also caused by scattering an reverberation (on rough ocean surface and bottom), refraction, and dispersion (due to the displacement of the reflection point caused by wind on the surface). Water depth plays a key role in determining the attenuation.” (n.d. “Underwater”)
AUVs: Autonomous Underwater Vehicles
Direct Link: Each node communicates directly with the station or underwater sink
Doppler Frequncy Spread: “Transmissions at a high data rate cause many adjacent symbols to interfere at the receiver, requiring sophisticated signal processing to deal with the generated ISI.” (n.d. “Underwater) It “generates: i) a simple frequency translation, which is relatively easy for a receiver to compensate for; ii) a continuous spreading of frequencies, which constitutes a non-shifted signal, which is more difficult for a receiver to compensate for. If a channel has a Doppler spread with bandwidth B and a signal has symbol duration T, then there are approximately BT uncorrelated samples of its complex envelope. When BT is much less than unity, the channel is said to be underspread and the effects of the Doppler fading can be ignored, while, if greater than unity, it is overspread.” (n.d. “Underwater)
DTPA: diethylenetriaminepentaacetic acid.
Ecotone: “geographic boundary or transition zone between two different groups of plant or animal distributions” (Harman 2004, “Ecotone”)
Geometric Spreading: “spreading of sound energy as a result of the expansion of the wavefronts. It increases with the propagation distance and is independent of frequency. There are two common kinds of geometric spreading: spherical (omni-directional point source), and cylindrical (horizontal radiation only).” (n.d. “Underwater)
ISI: Inter-Symbol Interference
Macronutrients and Micronutrients: nutrients necessary for plant growth. They affect crop growth, quality, and yield. The most important ones are copper, iron, manganese, and zinc. As pH increases, their availability lessens. Copper availability decreases as SOM increases. Clay has higher levels of them than sand. Free lime (CaCO3) precipitates them, and cooler, wetter soils tend to reduce their rate of consumption.
Multi-hop: each node relays information through the intermediate nodes to and from the station or underwater sink.
Multipath propagation: generates ISI. “The geometry depends on the link configuration. Vertical channels are characterized by little time dispersion, whereas horizontal channels may have extremely long multi-path spreads. The extent of the spreading is a strong function of depth and the distance between transmitter and receiver.” (n.d. “Underwater”)
ORNL: Oak Ridge National Laboratory
OSs: on-shore sinks
Particle Matter: particle pollution. aerially suspended, microscopic solids and liquids The greatest health problems are caused by particles less than 10mm in diameter because of their ability to get into the bloodstream and lungs, i.e. acids, metals, dust, and allergens. Fine particles are 2.5mm or less, i.e. Smoke and haze. Coarse particles are between 2.5 and 20mm, and include dust.
RF: radio frequency
RTT: round trip time
SOM: Soil Organic Matter is primarily plant residues. It “helps stabilize soil particles, thus decreasing erosion. It also improves soil structure and workability, enhances aeration and water penetration, increases water-holding capacity, and stores and supplies nutrients for growth of both plants and soil micro-organisms” (n.d. “AESA”). Temperature, Rainfall, Tillage, and Fertilization all affect the amount of SOM. High temperatures and dry climates reduce it due to increased decomposition. Tillage also decreases it due to aeration and the resulting drier soil. Fertilization increases it by increasing plant productivity.
Underwater Sinks: relays data from Ocean Floor Network to surface station
Uss: Underwater Sinks
UW-ASNs: Underwater Wireless Acoustic Sensor Networks