ITS Berkeley

Improved Power Grid Stability and Efficiency with a Building-Energy Cyber-Physical System

Piette, Mary Ann
Bayen, Alexandre M.
2009

This position article outlines some challenges of demand response in the context of the power grid and its interaction with buildings. We describe significant issues in energy-efficient operation of buildings, in particular questions such as system reliability, risk management and environmental impact. We also outline a strategy for the development of new technologies for a cyber-physical infrastructure system that integrates management of smart buildings with management of the power grid. Specific emphasis is given to the interaction of physical and computational processes through sensing,...

Guaranteed Bounds on Highway Travel Times Using Probe and Fixed Data

Claudel, Christian G.
Bayen, Alexandre M.
2009

This article investigates the problem of incorporating mobile probe data collected from GPS equipped cell phones into estimation algorithms for travel time. We use kinematic wave theory to create a modeling framework capable of incorporating trajectory data into the model. The problem of including loop detector data in this model is performed using a standard approach available in the literature. The problem of fusing this data with probe data is formulated using the Moskowitz function, which results from kinematic wave theory. Using this formulation, two linear programs are posed to...

Delay Pattern Estimation for Signalized Intersections Using Sampled Travel Times

Ban, Xuegang (Jeff)
Bayen, Alexandre M.
2009

Intersection delays are the major contributing factor to arterial delays. Methods to estimate intersection delay patterns by using measured travel times are studied. The delay patterns provide a way to estimate the delay for any vehicle arriving at the intersection at any time, which is useful for providing time-dependent intersection delay information to the driving public. The model requires sampled travel times between two consecutive locations on arterial streets, one upstream and the other downstream of a signalized intersection, without the need to know signal timing or traffic flow...

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...

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

Tinka, A.
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...

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...

Optimal Sensor Requirements

Ban, Xuegang (Jeff)
Bayen, Alexandre M.
Chu, Lianyu
Danczyk, Adam
Herrera, Juan‐Carlos
2009

PATH Task ORder 6328 addresses the optimal deployment of traffic detectors on freeway to ensure that adequate information is collected at the lowest possible cost. The project team produced a study framework and tools that can be applied locally to test the sensitivity of traffic data quality to detectors location and spacing, and ultimately recommend a deployment plan.Various types of traffic detectors, including loop detectors, radars, toll tag readers and video cameras are deployed on highways. They provide the data needed to run traffic management applications such as ramp metering...

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