Modeling

A Systems Approach to Sizing of Co-operative High-Accuracy Location (C-HALO) Services Validated by Experiments in San Francisco

Ekambaram, Venkatesan N.
Manasseh, Christian
Goodliss, Adam
Raja Sengupta
Ramchandran, Kannan
2011

This paper presents a methodology for assessing the accuracy gap between the current level-of-service provided by the US GPS constellation and DGPS, and the level-of-service envisaged by new Cooperative High-Accuracy LOcation (C-HALO) services that achieve decimeter accuracy. We present a novel GIS-based Hidden-Markov Model (HMM) predictive framework to estimate the fraction of roads with low satellite visibility counts that we call as the “dark area”, where C-HALO cannot be realized. Out of the total area of San Francisco (121 sq.km), 0.3 to 4% of the San Francisco streets are predicted...

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

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

BigActors: a Model for Structure-Aware Computation

Pereira, Eloi
Kirsch, Christoph M.
De Sousa, João Borges
Raja Sengupta
2013

This paper describes a model of computation for structure-aware computing called the BigActor model. The model is a hybrid. It combines the Actor model [1] and the Bigraph model [10]. The contributions of this paper are an operational semantics, an example illustrating how the model supports the concise programming of a mobile agent working in a ubiquitous computing world, a query language enabling a bigActor to observe the world around it, and a definition giving semantics to the feedback loop in control theory in the context of this model. This is followed by three theorems showing how...

Overcoming battery life problems of smartphones when creating automated travel diaries

Jariyasunant, Jerald
Raja Sengupta
Joan Walker
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 Runtime System for Logical-Space Programming

Pereira, Eloi
Krainer, Clemens
Da Silva, Pedro Marques
Kirsch, Christoph M.
Raja Sengupta
2015

In this paper we introduce logical-space programming, a spatial computing paradigm where programs have access to a logical space model, i.e., names and explicit relations over such names, while the runtime system is in charge of manipulating the physical space. Mobile devices such as autonomous vehicles are equipped with sensors and actuators that provide means for computation to react upon spatial information and produce effects over the environment. The spatial behavior of these systems is commonly specified at the physical level, e.g., GPS coordinates. This puts the responsibility for...

A Power Consumption Model for Multi-Rotor Small Unmanned Aircraft Systems

Liu, Zhilong
Raja Sengupta
Kurzhanskiy, Alex
2017

We develop a theoretical power consumption model for multi-rotor Unmanned Aircraft Systems (UAS), estimate the model parameters, and validate it by flying an IRIS+ quadrotor UAS and measuring its energy consumption experimentally. The model is derived from the helicopter literature. Such models are required to create UAS flight planning systems.

Integrating Flight and Charging Schedules in Urban Air Mobility

Cao, Shangqing
Jiang, Xuan
Bulusu, Vishwanath
Chakrabarty, Anjan
Mark Hansen
Onat, Emin
Raja Sengupta
Zou, Bo
2024

This paper investigates the simultaneous optimization of flight schedule and charging policy of electric vertical takeoff and landing aircraft for Urban Air Mobility operations. An optimization model is developed for a two-vertiport system to design an efficient flight schedule, including re-balancing flights, and a charging policy that serves a given demand with the objective of minimizing the required fleet size. The results highlight that charging aircraft to a lower State of Charge level during peak demand periods and to a higher level during off-peak times effectively reduces the...

Simulation-Based Optimization for Vertiport Location Selection: A Surrogate Model With Machine Learning Method

Jiang, Xuan
Cao, Shangqing
Mo, Baichuan
Cao, Junzhe
Yang, Hao (Frank)
Tang, Yuhan
Mark Hansen
Zhao, Jinhua
Raja Sengupta
2025

We present Vertiport-informed Surrogate-Based Optimization with Machine Learning Surrogates (VinS), a novel framework for solving the vertiport location problem for urban air mobility operations. The primary focus of this work is on the optimization of vertiport locations to facilitate efficient urban air transportation. Our framework helps choose not only the optimal vertiport locations but also the optimal number of vertiports. We develop a simulation model to analyze the impacts of various vertiport location configurations on the efficiency of the transportation network. To expedite the...

Department of Computer Sciences University of Salzburg, Austria

Raja Sengupta
2025

Data center cloud computing distinguishes computational services such as database transactions and data storage from computational resources such as server farms and disk arrays. Cloud computing enables a software-as-a-service business model where clients may only pay for the service they really need and providers may fully utilize the resources they actually have. The key enabling technology for cloud computing is virtualization. Recent developments, including our own work on virtualization technology for embedded systems, show that service-oriented computing through virtualization may...

Deterministic Models for Degraded Airside Capacity and Delays

Jasenka Rakas
Schonfeld, Paul
2004

This paper presents deterministic models for estimating airspace and airport capacity and delays during equipment outages. The National Airspace System (NAS) is very complex and consists of almost 48,000 reportable facilities and services that support air traffic control with very diverse functions and technologies. To better understand NAS performance and develop a methodology for estimating degraded capacity, previous studies about equipment outages and about airspace and airport performance are first reviewed. A deterministic aircraft separation model is used to estimate degraded...