Modeling

Failure Diagnosis Using Discrete-Event Models

Sampath, M.
Sengupta, R.
Lafortune, S.
Sinnamohideen, K.
Teneketzis, D.C.
1996

Detection and isolation of failures in large, complex systems is a crucial and challenging task. The increasingly stringent requirements on performance and reliability of complex technological systems have necessitated the development of sophisticated and systematic methods for the timely and accurate diagnosis of system failures. We propose a discrete-event systems (DES) approach to the failure diagnosis problem. This approach is applicable to systems that fall naturally in the class of DES; moreover, for the purpose of diagnosis, continuous-variable dynamic systems can often be viewed as...

Integrated development process for automated or driver-assist vehicles

Sousa, Joao Borges de
Misener, James A.
Sengupta, Raja
2002

We describe the methodology, tools and technologies for designing and implementing communication and control systems for networked automated or driver assist vehicles. In addressing design, we discuss enabling methodologies and our suite of enabling computational tools for formal modeling, simulation, and implementation. We illustrate our description with design, development and implementation work we have performed for Automated Highway Systems, Autonomous Underwater Vehicles, Mobile Offshore Base, Unmanned Air Vehicles, and Cooperative Adaptive Cruise Control. We conclude with the...

Kalman Filter-Based Integration of DGPS and Vehicle Sensors for Localization

Rezaei, Shahram
Sengupta, Raja
2007

We present a position estimation scheme for cars based on the integration of global positioning system (GPS) with vehicle sensors. The aim is to achieve enough accuracy to enable in vehicle cooperative collision warning, i.e., systems that provides warnings to drivers based on information about the motions of neighboring vehicles obtained by wireless communications from those vehicles, without use of ranging sensors. The vehicle sensors consist of wheel speed sensors, steering angle encoder, and a fiber optic gyro. We fuse these in an extended Kalman filter. The process model is a dynamic...

Middleware to enhance mobile communications for road safety and traffic mobility applications

Manasseh, C.
Sengupta, R.
2010

Middleware has emerged as an important architectural component in supporting distributed applications. The role of middleware is to present a unified programming model to application writers and to mask out problems of heterogeneity and distribution. It is motivated by the convergence of the embedded sensor and mobile communication revolutions in the automobile industry. The vehicle fleet is morphing into a vast mobile sensor fleet. The authors provide a middleware architecture and implementation that addresses the needs of a distributed system of mobile sensors comprised of vehicles and...

Modeling and controlling the structure of heterogeneous mobile robotic systems: A bigactor approach

Pereira, Eloi
Potiron, Camille
Kirsch, Chirstoph M.
Sengupta, Raja
2013

In this paper we address the problem of modelling and controlling heterogeneous mobile robotic systems at a structure-level abstraction. We consider a system of mobile robotic entities that are able to observe, control, compute, and communicate. They operate upon an abstraction of the structure of the world that entails location and connectivity as first-class concepts. Our approach is to model mobile robotic entities as bigActors [18], a model of computation that combines bigraphs with the actor model for modeling structure-aware computation. As case study, we model a mission of...

Numerical Simulation and Spectral Analysis of Pressure Fluctuations in Vehicle Aerodynamic Noise Generation

Duncan, Bradley D.
Sengupta, Raja
Mallick, Swapan
Shock, Rick
Sims-Williams, D. B.
2002

A new approach is proposed and demonstrated for investigation of the spatial structure of fluctuations in unsteady aerodynamics results obtained using CFD. This approach is used in this study to isolate unsteadiness in the flow field due to coherent structures at relatively high frequency from the dominant organized motion, as well as from the computational noise, in unsteady data obtained from CFD simulations. These simulations are performed using the commercial CFD software, PowerFLOW, which employs a Lattice Boltzmann method and a very large-eddy simulation (VLES) model for small-scale...

Overcoming battery life problems of smartphones when creating automated travel diaries

Jariyasunant, Jerald
Sengupta, Raja
Walker, Joan
2014

Gathering data using travel diaries has been a requirement to analyze travel behaviour data for decades. Traditional pen and paper techniques of gathering data has been complemented by new technologies, most recently GPS loggers, and now smartphones. Smartphones appear to be the silver bullet in collecting travel data on a wide scale, they are widespread, applications are easy to distribute, and the hardware is reliable. However, conserving the battery life in smartphones is a challenge to creating automated travel diaries. The smartphone is not solely a travel diary tool and for a system...

A Model for Selecting the Best Sustainable Airport Technology Alternatives

Tchivwila, Moïse Biampata
Rakas, Jasenka
Hendrickson, Thomas P.
Nikolic, Milos
2025

Air transport is a continually expanding industry, a fact that has become even more evident with the recovery of the aviation industry post-COVID-19. This expansion amplified energy consumption at airports, which was already significantly high. Airport decision-makers are increasingly focusing on improving sustainability and addressing social, economic, and environmental criteria across airports worldwide. In this article, we propose a decision-making model for identifying a sustainable airport technology solution that minimizes the energy consumption of airport lighting while considering...

Tracking the position of neighboring vehicles using wireless communications

Rezaei, Shahram
Sengupta, Raja
Krishnan, Hariharan
Guan, Xu
Bhatia, Raman
2010

We investigate four communication schemes for Cooperative Active Safety System (CASS) and compare their performance with application level reliability metrics. The four schemes are periodic communication, periodic communication with model, variable communication, and variable communication with repetition. CASS uses information communicated from neighboring vehicles via wireless network in order to actively evaluate driving situations and provide warnings or other forms of assistance to drivers. In CASS, we assume that vehicles are equipped with a GPS receiver, a Dedicated Short Range...

Distributed Mechanisms for Determining NAS-Wide Service Level Expectations: Final Report

Ball, Michael
Barnhart, Cynthia
Hansen, Mark
Kang, Lei
Liu, Yi
Swaroop, Prem
Vaze, Vikrant
Yan, Chiwei
2014

During the final year of the Service Level Expectation (SLE) project the NEXTOR-II team refined the models, completed development of the concept evaluation software and carried out a variety of user outreach activities. Specifically, much effort was devoted to supporting a human-in-the-loop (HITL) simulation. In addition to completing the software, the team produced a variety of tools to support the HITL participants. The team also separately reached out to flight operators to obtain both formal and informal feedback on system concepts and mechanisms.