Data

Data reconciliation of an open channel flow network using modal decomposition

Wu, Qingfang
Litrico, Xavier
Bayen, Alexandre M.
2009

This article presents a method to estimate flow variables for an open channel network governed by the linearized Saint-Venant equations and subject to periodic forcing. The discharge at the upstream end of the system and the stage at the downstream end of the system are defined as the model inputs; the flow properties at selected internal locations, as well as the other external boundary conditions, are defined as the outputs. Both inputs and outputs are affected by noise and we use the model to improve the data quality. A spatially dependent transfer matrix in the frequency domain is...

Lagrangian sensing: traffic estimation with mobile devices

Bayen, Alexandre M.
Work, Daniel B.
2009

An inverse modeling algorithm is developed to reconstruct the state of traffic (velocity field) on highways from GPS measurements gathered from mobile phones traveling on-board vehicles. The algorithm is based on ensemble Kalman filtering (EnKF), to overcome the nonlinearity and non-differentiability of a distributed highway traffic model for velocity. The algorithm is implemented in an architecture which includes GPS enabled phones and a privacy aware data collection infrastructure based on the novel concept of virtual trip lines (a technology developed by Nokia). The data collection...

Comparison of two data assimilation algorithms for shallow water flows

Strub, Issam S.
Bayen, Alexandre M.
2009

This article presents the comparison of two algorithms for data assimilation of two dimensional shallow water flows. The first algorithm is based on a linearization of the model equations and a quadratic programming (QP) formulation of the problem. The second algorithm uses Ensemble Kalman Filtering (EnKF) applied to the non-linear two dimensional shallow water equations. The two methods are implemented on a scenario in which boundary conditions and Lagrangian measurements are available. The performance of the methods is evaluated using twin experiments with experimentally measured...

Modeling and Optimization Analysis of a Single-Flagellum Micro-Structure Through the Method of Regularized Stokeslets

Bayen, Alexandre M.
2009

Bacteria such as Rhodobacter sphaeroides use a single flagellum for propulsion and change of orientation. These types of simple organisms have inspired microrobotic designs with potential applications in medicine, which motivates this work. In this paper, an elastic model for a single-flagellum micro-structure is presented and followed by an analysis of the system based on optimization. The model is based on the method of Regularized Stokeslets which allows for a discretization of the system into particles connected by spring forces. The optimization analysis leads to the design of an...

Réconciliation de Données d'un Réseau Hydraulique à Surface Libre à L'aide de la Décomposition Modale

Wu, Qingfang
Bayen, Alexander M.
2009

Data reconciliation of an open channel flow network using modal decomposition

Preface

Bastin, George
Bayen, Alexandre M.
2009

Management of canal networks at the age of information technology. With the miniaturization of sensors and their decreasing costs, the paradigm of instrumentation of the built infrastructure and the environment has now been underway for several years, leading to numerous successful and sometimes spectacular realizations such as the instrumentation of the Golden Gate with wire- less sensors a few years ago. The convergence of communication, control and sensing on numerous platforms including multi-media platforms has enabled engineers to augment physical infrastructure systems with an...

Viability-based computation of spatially constrained minimum time trajectories for an autonomous underwater vehicle: implementation and experiments

Tinka, Andrew
Diemer, S.
2009

A viability algorithm is developed to compute the constrained minimum time function for general dynamical systems. The algorithm is instantiated for a specific dynamics (Dubin's vehicle forced by a flow field) in order to numerically solve the minimum time problem. With the specific dynamics considered, the framework of hybrid systems enables us to solve the problem efficiently. The algorithm is implemented in C using epigraphical techniques to reduce the dimension of the problem. The feasibility of this optimal trajectory algorithm is tested in an experiment with a light autonomous...

Path and travel time inference from GPS probe vehicle data

Hunter, Timothy
Herring, Ryan
Bayen, Alexandre M.
2009

We consider the problem of estimating real-time traffic conditions from sparse, noisy GPS probe vehicle data. We specifically address arterial roads, which are also known as the secondary road network (highways are considered the primary road network). We consider several estimation problems: historical traffic patterns, real-time traffic conditions, and forecasting future traffic conditions. We assume that the data available for these estimation problems is a small set of sparsely traced vehicle trajectories, which represents a small fraction of the total vehicle flow through the network. We...

Viability-based computation of spatially constrained minimum time trajectories for an autonomous underwater vehicle: implementation and experiments

Tinka, Andrew
Diemer, S.
Bayen, Alexandre M.
2009

A viability algorithm is developed to compute the constrained minimum time function for general dynamical systems. The algorithm is instantiated for a specific dynamics (Dubin's vehicle forced by a flow field) in order to numerically solve the minimum time problem. With the specific dynamics considered, the framework of hybrid systems enables us to solve the problem efficiently. The algorithm is implemented in C using epigraphical techniques to reduce the dimension of the problem. The feasibility of this optimal trajectory algorithm is tested in an experiment with a light autonomous...

Minimal Error Certificates for Detection of Faulty Sensors Using Convex Optimization

Claudel, Christian G.
Nahoum, Matthieu
Bayen, Alexandre M.
2009

This article proposes a new method for sensor fault detection, applicable to systems modeled by conservation laws. The state of the system is modeled by a Hamilton-Jacobi equation, in which the Hamiltonian is uncertain. Using a LaxHopf formula, we show that any local measurement of the state of the system restricts the allowed set of possible values of other local measurements. We derive these constraints explicitly for arbitrary Hamilton-Jacobi equations. We apply this framework to sensor fault detection, and pose the problem finding the minimal possible sensor error (minimal error...