Kishan Addagarla | Staffordshire University (original) (raw)

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Papers by Kishan Addagarla

Decision and Control, 2005 and 2005 …, Jan 1, 2005

The problem of distributed Kalman filtering (DKF) for sensor networks is one of the most fundamen... more The problem of distributed Kalman filtering (DKF) for sensor networks is one of the most fundamental distributed estimation problems for scalable sensor fusion. This paper addresses the DKF problem by reducing it to two separate dynamic consensus problems in terms of weighted measurements and inverse-covariance matrices. These to data fusion problems are solved is a distributed way using lowpass and band-pass consensus filters. Consensus filters are distributed algorithms that allow calculation of average-consensus of time-varying signals. The stability properties of consensus filters is discussed in a companion CDC '05 paper . We show that a central Kalman filter for sensor networks can be decomposed into n micro-Kalman filters with inputs that are provided by two types of consensus filters. This network of micro-Kalman filters collectively are capable to provide an estimate of the state of the process (under observation) that is identical to the estimate obtained by a central Kalman filter given that all nodes agree on two central sums. Later, we demonstrate that our consensus filters can approximate these sums and that gives an approximate distributed Kalman filtering algorithm. A detailed account of the computational and communication architecture of the algorithm is provided. Simulation results are presented for a sensor network with 200 nodes and more than 1000 links.

... SIMULATION, ALGORITHMS, COMPUTER PROGRAMS, THESES. Subject Categories :COMPUTER PROGRAMMING A... more ... SIMULATION, ALGORITHMS, COMPUTER PROGRAMS, THESES. Subject Categories :COMPUTER PROGRAMMING AND SOFTWARE COMPUTER HARDWARE. Distribution Statement : APPROVED FOR PUBLIC RELEASE.

International Journal of Computer …, Jan 1, 1989

Using known camera motion to estimate depth from image sequences is an important problem in robot... more Using known camera motion to estimate depth from image sequences is an important problem in robot vision. Many applications of depth-from-motion, including navigation and manipulation, require algorithms that can estimate depth in an on-line, incremental fashion. This requires a representation that records the uncertainty in depth estimates and a mechanism that integrates new measurements with existing depth estimates to reduce the uncertainty over time.

Monthly Weather Review, Jan 1, 1998

The possibility of performing data assimilation using the flow-dependent statistics calculated fr... more The possibility of performing data assimilation using the flow-dependent statistics calculated from an ensemble of short-range forecasts (a technique referred to as ensemble Kalman filtering) is examined in an idealized environment. Using a three-level, quasigeostrophic, T21 model and simulated observations, experiments are performed in a perfect-model context. By using forward interpolation operators from the model state to the observations, the ensemble Kalman filter is able to utilize nonconventional observations.

Monthly weather …, Jan 1, 1998

This paper discusses an important issue related to the implementation and interpretation of the a... more This paper discusses an important issue related to the implementation and interpretation of the analysis scheme in the ensemble Kalman filter. It is shown that the observations must be treated as random variables at the analysis steps. That is, one should add random perturbations with the correct statistics to the observations and generate an ensemble of observations that then is used in updating the ensemble of model states. Traditionally, this has not been done in previous applications of the ensemble Kalman filter and, as will be shown, this has resulted in an updated ensemble with a variance that is too low.

Decision and Control, 2005 and 2005 …, Jan 1, 2005

The problem of distributed Kalman filtering (DKF) for sensor networks is one of the most fundamen... more The problem of distributed Kalman filtering (DKF) for sensor networks is one of the most fundamental distributed estimation problems for scalable sensor fusion. This paper addresses the DKF problem by reducing it to two separate dynamic consensus problems in terms of weighted measurements and inverse-covariance matrices. These to data fusion problems are solved is a distributed way using lowpass and band-pass consensus filters. Consensus filters are distributed algorithms that allow calculation of average-consensus of time-varying signals. The stability properties of consensus filters is discussed in a companion CDC '05 paper . We show that a central Kalman filter for sensor networks can be decomposed into n micro-Kalman filters with inputs that are provided by two types of consensus filters. This network of micro-Kalman filters collectively are capable to provide an estimate of the state of the process (under observation) that is identical to the estimate obtained by a central Kalman filter given that all nodes agree on two central sums. Later, we demonstrate that our consensus filters can approximate these sums and that gives an approximate distributed Kalman filtering algorithm. A detailed account of the computational and communication architecture of the algorithm is provided. Simulation results are presented for a sensor network with 200 nodes and more than 1000 links.

... SIMULATION, ALGORITHMS, COMPUTER PROGRAMS, THESES. Subject Categories :COMPUTER PROGRAMMING A... more ... SIMULATION, ALGORITHMS, COMPUTER PROGRAMS, THESES. Subject Categories :COMPUTER PROGRAMMING AND SOFTWARE COMPUTER HARDWARE. Distribution Statement : APPROVED FOR PUBLIC RELEASE.

International Journal of Computer …, Jan 1, 1989

Using known camera motion to estimate depth from image sequences is an important problem in robot... more Using known camera motion to estimate depth from image sequences is an important problem in robot vision. Many applications of depth-from-motion, including navigation and manipulation, require algorithms that can estimate depth in an on-line, incremental fashion. This requires a representation that records the uncertainty in depth estimates and a mechanism that integrates new measurements with existing depth estimates to reduce the uncertainty over time.

Monthly Weather Review, Jan 1, 1998

The possibility of performing data assimilation using the flow-dependent statistics calculated fr... more The possibility of performing data assimilation using the flow-dependent statistics calculated from an ensemble of short-range forecasts (a technique referred to as ensemble Kalman filtering) is examined in an idealized environment. Using a three-level, quasigeostrophic, T21 model and simulated observations, experiments are performed in a perfect-model context. By using forward interpolation operators from the model state to the observations, the ensemble Kalman filter is able to utilize nonconventional observations.

Monthly weather …, Jan 1, 1998

This paper discusses an important issue related to the implementation and interpretation of the a... more This paper discusses an important issue related to the implementation and interpretation of the analysis scheme in the ensemble Kalman filter. It is shown that the observations must be treated as random variables at the analysis steps. That is, one should add random perturbations with the correct statistics to the observations and generate an ensemble of observations that then is used in updating the ensemble of model states. Traditionally, this has not been done in previous applications of the ensemble Kalman filter and, as will be shown, this has resulted in an updated ensemble with a variance that is too low.