[Firebug-cvs] firebug/web spie_2004.tex,1.7,1.8 spie_reviews.tex,1.3,1.4
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Update of /cvsroot/firebug/firebug/web In directory sc8-pr-cvs1:/tmp/cvs-serv10040a Modified Files: spie_2004.tex spie_reviews.tex Log Message: Copied main body of reviews into paper. The reviews file should be left as is, but the review in the main paper need to be condensed. Index: spie_2004.tex =================================================================== RCS file: /cvsroot/firebug/firebug/web/spie_2004.tex,v retrieving revision 1.7 retrieving revision 1.8 diff -C2 -d -r1.7 -r1.8 *** spie_2004.tex 21 Jul 2003 23:40:18 -0000 1.7 --- spie_2004.tex 22 Jul 2003 21:02:38 -0000 1.8 *************** *** 99,107 **** \subsection{Previous work with outdoor sensors} ! \input{spie_reviews} \paragraph{Mehta and El Zarki}~\cite{mehta:v2002} ???? \subsection{Pr\'ecis} --- 99,296 ---- \subsection{Previous work with outdoor sensors} ! %\input{spie_reviews} ! ! ! ! \paragraph{Ganesan et al.}~\cite{ganesan:d2002} ! have done the first large scale study ! for sensor networks to explore the behavior of such a ! distributed system. Their data provides insight into ! designing protocols and algorithms for scalable distributed ! sensor networks. They differentiate how each of the layers ! in the protocol stack, link, medium access, routing and ! application is affected. ! ! Their study involves using 150 motes laid out in a parking lot. ! Link characteristics and statistics as well as aggregate ! statistics for packet loss, and packet forwarding are gathered. ! At the medium access layer they use timing information to ! identify metrics that capture both end-to-end properties of a ! basic flood propagation, and local properties such as contention ! and collision. At the node level, they maintain the number of ! hops to the base-station and the number of children each node ! has to take into account the clustering dynamics. ! ! What is observed at scale is termed as non-uniform flood ! propagation. This is shown by the existence of backward links, ! long links, assymetrice links, nodes that are missed out in the ! flood process and even clustering behavior wherein a few nodes ! have many children. ! ! ! \paragraph{Bulusu et al.}~\citeyear{bulusu:n2002,bulusu:n2001} ! have developed techniques for ! RF-based localiazation in sensor ! networks. Their work can be divided into two ! distinct problem areas, namely localization, ! and beacon placement. They profess a GPS-less ! environments with beacon nodes that are ! deployed with their absolute location/position ! stored within them and sensor nodes that localize ! themselves based on proximity to a subset of beacons. ! ! Some of the salient characteristics of their approach are: ! ! \begin{itemize} ! ! \item an idealized radio model with perfect spherical ! radio propagation and identical transmission range for all radios, ! ! \item a localization algorithm that relies on a ! connectivity metric threshold to decide ! which beacons to use in computation of a nodes ! position estimate, which is the centroid ! of the beacons selected. ! ! \item measurement based adaptive beacon placement, ! which can adjust the density of beacons ! and in turn increasing system lifetime, ! and reduced excessive channel interference and ! contention. ! \end{itemize} ! ! As per their results the spherical radio model ! correlates upto 90% with real conditions in ! an outdoor uncluttered environment. ! ! ! ! \paragraph{Simic et al.}~\cite{simic:sn2003} ! describe distributed computation ! and estimation of a scalar field in a sensor ! network. The scalar field could be anything ! from temperature to amount or intensity of ! light. They provide an algorithm and precise ! theoretical analysis of it. ! ! The basic idea of their algorithm is as follows. ! Each node communicates with its neighbors ! and computes the maximal difference quotient ! of the sensed scalar field. The estimate ! of the gradient at each node is taken to be ! the vector in the corresponding direction with ! norm equal to the maximal difference quotient. ! The method amounts to approximate differentiation ! of the function defined by the scalar field, ! given its value on a set of random points. ! They analyze the accuracy and complexity of ! the algorithm from a probabilistic point of ! view. The estimated probability that the ! error is small and converges to one, as the ! number of nodes goes to infinity, is shown. ! ! ! \paragraph{West et al.}~\citeyear{west:b2001} ! are designing parts of the sensor ! network architecture with microclimate ! monitoring as their application for focus. ! Their necessities for an architecture stem ! from preliminary testing. To understand the ! performance of low-power transceivers, they ! have taken propagation measurements using ! commercially available equipment in the local ! Ponderosa pine forests. An interesting ! observation made in this environment was that if ! the antenna was placed at a height of less ! than 1 meter, the range severely degraded. ! ! Some of the suggestions that they make to ! expand current sensor network implementations ! and architectures are: ! \begin{itemize} ! \item Distributed source coding of spatio-temporally ! correlated vector process. ! \item Multi-hop protocols with inter-layer ! interaction, as interaction between layers ! may prove benfecial in a more compact and power efficient system design. ! \item Coded macrodiversity in energy-limited ! multi-hop nets where a transmission using a ! basic radio is heard by multiple neighboring nodes. ! \end{itemize} ! ! ! \paragraph{Ramadurai and Sichitui}~\citeyear{ramadurai:v2003,sichitiu:ml2003} ! develop distributed algorithms ! for outdoor localization in sensor networks. ! The method is based on radio-frequency (RF) signal strength ! measurements, which tend to have a certain degree ! of inaccuracy. They define two classes of nodes, ! namely unknown and beacon nodes. The "beacon" nodes have known ! absolute (using GPS) positions, and the "unknown" ! nodes do not know their positions. ! The beacon nodes peridically inject packets which ! are used to form position estimates ! at the unknown nodes. Once an unknown nodes has ! a rough idea of its position, it can ! assist other unknown nodes in estimating ! their position. ! ! They employ two techniques for associating signal ! strength measurements to distance. Both techniques ! are grounded through preliminary empirical data. ! The first uses bounded values that associate an ! RSSI reading to a distance range, plus adding power level ! variability gives it increased accuracy and granularity. ! The second uses probabilistic position estimation, ! where any node receiving a beacon packet will ! estimate itself to be located on a surface that ! has a probability distribution dictated by a mean and ! standard deviation corresponding to the signal ! strength received. ! ! The measurements for both these approaches were ! collected outdoors with very little interference, ! however their data also indicates that even in ! heavily wooded areas the signal propagation is ! approximately circular, and hence the signal strength is ! linearly proportional to the distance. ! ! ! \paragraph{Mainwaring et al.}~\citeyear{mainwaring:a2002} ! have had success in deploying ! large scale sensor networks as part of ! a habitat monitoring project at the Great Duck ! Island. It is reflective of the domain of applications ! for which sensor networks are going to be used. ! It serves as a collection of requirements, costraints ! and guidelines that serve as a basis for a general ! sensor network architecture. ! ! They present a tierd architecture, where at the ! lowest level are sensor nodes, which perform general ! purpose computing and are organized into sensor ! patches. Individual sensor nodes transmit their data ! through a patch to a sensor network gateway which links ! the sensor patch through a local transit network to ! a remote basestation. The transit network consists ! of one or more hops of wireless links. The current ! system consists of 32 nodes on a small island off ! the coast of Maine streaming live data onto the web. ! ! The main tasks at hand that the network spends ! resources for are 1) data sampling and collection, ! 2) communications, 3) network retasking and 4) ! health and status monitoring. Keeping these in mind, ! energy required for each task is projected and taken ! into account to estimate how long the sensor nodes ! will survive. ! ! \paragraph{Mehta and El Zarki}~\cite{mehta:v2002} ???? + + \subsection{Pr\'ecis} *************** *** 117,144 **** One paragraph summary of AM here. ! ! Tiny Active Messages ~\cite{hill:j2000} attempt to preserve the ! basic concepts of integrating communication with computation ! and matching communication primitives to hardware ! capabilities. Each message contains the name of a ! user-level handler to be invoked on a target node upon arrival ! and a data payload to pass in as arguments. The handler function ! serves the dual purpose of extracting the message from the network ! and either integrating the data into the computation ! or sending a response message. The basic paradigm of typed messages ! causing handlers to be invoked upon arrival matches up ! well with the event based programming model supported ! by TinyOS (the operating system) and demanded by the underlying ! sensor hardware. The low overhead associated with event based ! notification is complementary to the limited resources of networked ! sensors. Applications do not need to waste resources ! while waiting for messages to arrive. Additionally, ! the overlap of computational work with application ! level communication is essential. Execution contexts and ! stack space must never be wasted because applications are ! blocked, waiting for communication. Essentially, the active ! messages communication model can be viewed as a ! distributed eventing model where networked nodes send ! each other events. --- 306,333 ---- One paragraph summary of AM here. ! ! Tiny Active Messages ~\cite{hill:j2000} attempt to preserve the ! basic concepts of integrating communication with computation ! and matching communication primitives to hardware ! capabilities. Each message contains the name of a ! user-level handler to be invoked on a target node upon arrival ! and a data payload to pass in as arguments. The handler function ! serves the dual purpose of extracting the message from the network ! and either integrating the data into the computation ! or sending a response message. The basic paradigm of typed messages ! causing handlers to be invoked upon arrival matches up ! well with the event based programming model supported ! by TinyOS (the operating system) and demanded by the underlying ! sensor hardware. The low overhead associated with event based ! notification is complementary to the limited resources of networked ! sensors. Applications do not need to waste resources ! while waiting for messages to arrive. Additionally, ! the overlap of computational work with application ! level communication is essential. Execution contexts and ! stack space must never be wasted because applications are ! blocked, waiting for communication. Essentially, the active ! messages communication model can be viewed as a ! distributed eventing model where networked nodes send ! each other events. Index: spie_reviews.tex =================================================================== RCS file: /cvsroot/firebug/firebug/web/spie_reviews.tex,v retrieving revision 1.3 retrieving revision 1.4 diff -C2 -d -r1.3 -r1.4 *** spie_reviews.tex 21 Jul 2003 23:40:56 -0000 1.3 --- spie_reviews.tex 22 Jul 2003 21:02:38 -0000 1.4 *************** *** 189,190 **** --- 189,194 ---- into account to estimate how long the sensor nodes will survive. + + + + \paragraph{Mehta and El Zarki}~\cite{mehta:v2002} ???? |