A sensor network is subject to a unique set of resource constraints such as

In a typical sensor network, each sensor node operates untethered and has a microprocessor and a small amount of memory for signal processing and task scheduling

Each node is equipped with one or more sensing devices such as acoustic microphone arrays, video or still cameras, IR, seismic or magnetic sensors

Information collected by and transmitted on a sensor network describes conditions of physical environments and requires advanced query interfaces and search engines to effectively support user-level functions

_______ routes user queries or commands to appropriate nodes in a sensor network

Communicating one bit over the wireless medium at short ranges consumes _____ energy than processing that bit

A sensor network is designed to collect information from a _____ environment

It is more appropriate to address nodes in a sensor network by _______than by ________.

Mobility and instability in wireless links prevent the use of many existing edge network gateway protocols for internetworking IP and sensor networks

The challenges we face in designing sensor network systems and applications include

1. Limited hardware
2. Limited support for networking
3. Limited support for software development

a. The tasks are typically real-time and massively distributed, involve dynamic collaboration among nodes, and must handle multiple competing events

b. Each node has limited processing, storage and communication capabilities, and limited energy supply and bandwidth

c. The network is peer-to-peer, with a mesh topology and dynamic, mobile and unreliable connectivity

Advantages of sensor network are

Dense networks of distributed communicating sensors can improve SNR by reducing average distances from sensor to source of signal or target

The greatest advantage of networked sensing are in improved _____

A ____ sensing system is inherently more robust against individual sensor node or link failures, because of redundancy in the network

Because of the unique attenuation characteristics of RF signals, ______network provides a significant energy saving over _______ network for the same distance

The RF attenuation model near the ground is given by

In the above expression, alpha is typically in the range of __ to __ (2/3/4/5)

The power advantage of an N-hop transmission versus a single hop transmission over the same distance Nr is

In above expression, _______N gives a larger power saving due to the consideration of RF energy alone

Using more nodes increases the

Each sensor has a finite sensing range, determined by the ___ floor of the sensor.

Denser sensor field improves the odds of detecting a signal source within the range

Once a signal source is inside the sensing range of a sensor, further increasing the sensor density ______ the average distance from a sensor to the signal source, hence improving the SNR

With respect to the acoustic sensing case in a twodimensional plane, the acoustic power received at a distance r is given by

With respect to the acoustic sensing case in a two dimensional plane, the SNR is given by

The SNR advantage of the denser sensor network is given by

An increase in sensor density by a factor of k improves the SNR at a sensor by ____ dB.

A sensor network is designed to perform a set of high level information processing tasks such as

Following are sample commercial and military applications include

1. Environmental monitoring a. Intelligent home, responsive environment

2.Industrial sensing and diagnostics b. Multi-target tracking

3.Infrastructure protection c. Power grids, water distribution

4. Battlefield awareness d. Traffic, habitat, security

5.Context aware computing e.Airplanes, factory and supply chains

If every sensor has some data that it needs to send to another node in a network, then per node throughput scales as _____

As the number of nodes _____, every nodes spend almost all of its time forwarding packets of other nodes

_____ refers to signal and information processing problems determined by the issue of selecting embedded sensors to participate in an information processing task

_______ is an interdisciplinary research area that draws on contribution from signal processing, networking and protocols, databases and information management, distributed algorithms, and embedded systems and architecture

A basic unit with on-board sensors, memory, wireless modem and power supply

A connectivity graph where nodes are sensor nodes

and edges are communication links

The process of determining a network path from a packet source node to its destination

Routing of a data based on geographical attributes such as locations or regions

Approaches that name, route or access a piece of data via properties that are external to a communication network

A style of processing in which the data is processed and combined near where the data is generated

Sensors cooperatively processing data from multiple sources in order to serve a high level task

A snapshot about a physical environment or a snapshot of the system itself

Either high level system tasks which may include sensing, communication, processing and resource allocation or application tasks which may include detection, classification, localization or tracking

The process of discovering the existence of a physical phenomenon

The assignment of class labels to a set of physical phenomena being observed

The estimation of the state of physical entity such as a physical phenomenon or a sensor node from a set of measurements

A mapping of data to a scalar number, in the context of overall system task and knowledge

The assignment of sensors to a particular task and the control of sensor state for accomplishing the task

Sensors, communication links, processors, on board memory and node energy reserves

Services such as time synchronization and node localization that enable applications to discover properties of a node and the nodes to organize themselves into a useful network

Sensor information is stored, indexed and accessed by applications

The run-time system support for sensor network applications

The abstract characterization of system properties

A measurable quantity that describes how well the system is performing on some absolute scale