https://www.cs.montana.edu/courses/csci566/Ref/WMSN-Survey.pdf

A survey on wireless multimedia sensor networks

Visual sensor networks have emerged as an important
class of sensor-based distributed intelligent systems,
with unique performance, complexity, and quality of service
challenges. Consisting of a large number of low-power camera nodes,
visual sensor networks support a great number of novel
vision-based applications. The camera nodes provide information
from a monitored site, performing distributed and collaborative
processing of their collected data. Using multiple cameras in the
network provides different views of the scene, which enhances
the reliability of the captured events. However, the large amount
of image data produced by the cameras combined with the
network's resource constraints require exploring new means
for data processing, communication, and sensor management.
Meeting these challenges of visual sensor networks requires
interdisciplinary approaches, utilizing vision processing, communications
and networking, and embedded processing. In this
paper, we provide an overview of the current state-of-the-art in
the field of visual sensor networks, by exploring several relevant
research directions. Our goal is to provide a better understanding
of current research problems in the different research fields of
visual sensor networks, and to show how these different research
fields should interact to solve the many challenges of visual sensor
networks.

/pdf/a-survey-of-visual-sensor-networks-38iexc9185.pdf

A Survey of Visual Sensor Networks

The availability of low-cost hardware is enabling the development of wireless multimedia sensor networks (WMSNs), i.e., networks of resource-constrained wireless devices that can retrieve multimedia content such as video and audio streams, still images, and scalar sensor data from the environment. In this paper, ongoing research on prototypes of multimedia sensors and their integration into testbeds for experimental evaluation of algorithms and protocols for WMSNs are described. Furthermore, open research issues and future research directions, both at the device level and at the testbed level, are discussed. This paper is intended to be a resource for researchers interested in advancing the state-of-the-art in experimental research on wireless multimedia sensor networks.

Wireless Multimedia Sensor Networks: Applications and Testbeds

Wireless Multimedia Sensor Networks (WMSNs) have emerged and shifted the focus from the typical scalar wireless sensor networks to networks with multimedia devices that are capable to retrieve video, audio, images, as well as scalar sensor data. WMSNs are able to deliver multimedia content due to the availability of inexpensive CMOS cameras and microphones coupled with the significant progress in distributed signal processing and multimedia source coding techniques. In this paper, we outline the design challenges of WMSNs, give a comprehensive discussion of the proposed architectures, algorithms and protocols for the different layers of the communication protocol stack for WMSNs, and evaluate the existing WMSN hardware and testbeds. The paper will give the reader a clear view of the state of the art at all aspects of this research area, and shed the light on its main current challenges and future trends. We also hope it will foster discussions and new research ideas among its researchers.

/pdf/wireless-multimedia-sensor-networks-current-trends-and-53txtgfb7z.pdf

Wireless Multimedia Sensor Networks: Current Trends and Future Directions

Pumas (Puma concolor) live in diverse, often rugged, complex habitats. The energy they expend for hunting must account for this complexity but is difficult to measure for this and other large, cryptic carnivores. We developed and deployed a physiological SMART (species movement, acceleration, and radio tracking) collar that used accelerometry to continuously monitor energetics, movements, and behavior of free-ranging pumas. This felid species displayed marked individuality in predatory activities, ranging from low-cost sit-and-wait behaviors to constant movements with energetic costs averaging 2.3 times those predicted for running mammals. Pumas reduce these costs by remaining cryptic and precisely matching maximum pouncing force (overall dynamic body acceleration = 5.3 to 16.1g) to prey size. Such instantaneous energetics help to explain why most felids stalk and pounce, and their analysis represents a powerful approach for accurately forecasting resource demands required for survival by large, mobile predators.

http://science.sciencemag.org/content/sci/346/6205/81.full.pdf

Instantaneous energetics of puma kills reveal advantage of felid sneak attacks

In this work we characterize the energy consumption of a visual sensor network testbed. Each node in the testbed consists of a "single-board computer", namely Crossbow's Stargate, equipped with a wireless network card and a Webcam. We assess energy consumption of activities representative of the target application (e.g., perimeter surveillance) using a benchmark that runs (individual and combinations of) "basic" tasks such as processing, flash memory access, image acquisition, and communication over the network. In our characterization, we consider the various hardware states the system switches through as it executes these benchmarks, e.g., different radio modes (sleep, idle, transmission, reception), and Webcam modes (off, on, and acquiring image). We report both steady-state and transient energy consumption behavior obtained by direct measurements of current with a digital multimeter. We validate our measurements against results obtained using the Stargate's on-board energy consumption measuring capabilities.

/pdf/characterizing-energy-consumption-in-a-visual-sensor-network-489z9rwktr.pdf

Characterizing energy consumption in a visual sensor network testbed

We present CARNIVORE, a system for in situ, unobtrusive monitoring of cryptic, difficult-to-catch/observe wildlife in their natural habitat. CARNIVORE is a network of mobile and static nodes with sensing, processing, storage, and wireless communication capabilities. CARNIVORE's compact, low-power, mobile animal-borne nodes collect sensor data and transmit it to static nodes, which then relay it to the Internet. Depending on the wildlife being studied, the network can be quite sparse and therefore disconnected frequently for arbitrarily long periods of time. To support "disconnected operation", CARNIVORE uses an "opportunistic routing" approach taking advantage of every encounter between nodes (mobile-to-mobile and mobile-to-static) to propagate data. With a lifespan of 50-100 days, a CARNIVORE mobile node, outfitted on a collar, collects and transmits 1 GB of data compared to 450 kB of data from comparable commercially available wildlife collars. Each collar records 3-axis accelerometer and GPS data to infer animal behavior and energy consumption.Testing in both laboratory and free-range settings with domestic dogs shows that galloping and trotting behavior can be identified. Data collected fromfirst deployments on mountain lions (Puma concolor) near Santa Cruz, CA, USA show that the system is a viable and useful tool for wildlife research.

/pdf/carnivore-a-disruption-tolerant-system-for-studying-wildlife-57e80nho40.pdf

CARNIVORE: a disruption-tolerant system for studying wildlife

In this paper we introduce a novel collision-free, schedule-based medium access control protocol for wireless networks Our protocol, TRANSFORMA (TRAffic FORecasting Medium Access) uses traffic forecasting to significantly reduce packet delivery delays for delay-sensitive applications while maintaining delivery ratios higher than those of contention-based protocols TRANSFORMA's novel approach to channel access uses the forecast data rate of each application flow to perform distributed probabilistic channel scheduling We show through simulations that, thanks to its per-application traffic forecasting capabilities, TRANSFORMA yields lower average delays when compared against DYNAMMA, an existing schedule-based MAC, and against 80211 under high load TRANSFORMA caters to emerging high data rate, real-time services that will likely be prevalent particularly at the edges of the Internet of the future Such services which are currently represented by applications such as Skype, Google Talk, and iChat, exhibit traffic characteristics that are fairly predictable and thus well served by TRANSFORMA's traffic forecasting abilities

Collision-free medium access based on traffic forecasting

During the last decade, the success and popularity of wireless standards such as IEEE 802.11 have drawn the attention of the research community to wireless networks. A great amount of effort has been invested into research in this area, most of which relies heavily on simulation and analysis techniques. However, simulations do not precisely control hardware interrupts, packet timing and real physical and MAC layer behaviors. As a result, simulation results need to be validated by real implementations, which is evident by the change in focus of research activities increasingly moving towards real implementations, including the deployment of testbeds as a main tool to analyze network protocol functionality. Under this context, we present an overview of SCORPION (Santa Cruz mObile Radio Platform for Indoor and Outdoor Networks), a heterogeneous wireless networking testbed that includes a variety of nodes ranging from ground vehicles to autonomous aerial vehicles. The purpose of SCORPION to is to deploy and investigate nascent networking protocols using a variety of mobile platforms utilizing structured as well as unstructured mobility patterns.

SCORPION: a heterogeneous wireless networking testbed

In this paper, we explore the idea of using traffic forecasting to improve the delay performance of a schedule-based medium access control protocol. Schedule-based channel access has been shown to utilize network and energy resources efficiently but is often hindered by the extra delay that scheduling introduces. We explore the use of traffic forecasting to anticipate transmission schedules instead of establishing them reactively, thereby reducing scheduling delays. We show the potential performance benefits traffic forecasting can bring to schedule-based medium access in the context of an existing MAC protocol called DYNAMMA [14]. Preliminary results using a machine-learning based traffic forecasting technique are also presented.

Vladislav Petkov

Papers

Characterizing energy consumption in a visual sensor network testbed

CARNIVORE: a disruption-tolerant system for studying wildlife

Collision-free medium access based on traffic forecasting

SCORPION: a heterogeneous wireless networking testbed

The case for using traffic forecasting in schedule-based channel access