Showing papers by "Sunderesh S. Heragu published in 2011"
TL;DR: In this article, the authors model variants of the two systems as an open queuing network (OQN) and use an existing tool for the analysis of OQNs, called the manufacturing system performance analyser (MPA), for analysing the performance of the AS/RS and AVS/RS.
Abstract: Automated storage and retrieval systems (AS/RSs) and autonomous vehicle storage and retrieval systems (AVS/RSs) are two competing technologies for the handling, storage and retrieval of unit-loads in the reserve section of an automated warehouse. In this paper, we model variants of the two systems as an open queuing network (OQN) and use an existing tool for the analysis of OQNs, called the manufacturing system performance analyser (MPA), for analysing the performance of the AS/RS and AVS/RS. Experimental results are provided to show that MPA is a better choice than simulation to quickly evaluate alternate configurations of the two systems. We use MPA to answer a series of design questions for AS/RS and AVS/RS design conceptualisation.
104 citations
TL;DR: Simulation based performance analysis of an autonomous vehicle storage and retrieval system (AVS/RS) finds that having a large number of lifts (zones) and a large footprint yield better performance.
52 citations
TL;DR: This paper provides solutions for various single-class, SOQN models assuming multiple servers and general interarrival and service time distributions and demonstrates the effectiveness of this approach.
Abstract: Although semi-open queuing networks (SOQNs) more accurately represent many problems encountered in manufacturing and logistical applications, they have not been as widely studied as open or closed queuing networks. The SOQN is a more realistic model of a system in many instances because it includes the time a customer waits outside the system. In this paper, we provide solutions for various single-class, SOQN models assuming multiple servers and general interarrival and service time distributions. Experimental results are provided to demonstrate the effectiveness of our approach.
22 citations
11 Dec 2011
TL;DR: An agent-based simulation model of a pandemic within a generic US metropolitan area is developed along with the effects associated with mitigation strategies involving home confinement and school closure, along with a comparison of the two strategies.
Abstract: Millions of people have been infected and died as results of influenza pandemics in human history. In order to prepare for these disasters, it is important to know how the disease spreads. Further, intervention strategies should be implemented during the pandemics to mitigate their ill effects. Knowledge of how these interventions will affect the pandemic course is paramount for decision makers. This paper develops an agent-based simulation model of a pandemic within a generic US metropolitan area, along with the effects associated with mitigation strategies involving home confinement and school closure. Also, a comparison of the two strategies and their variants is presented.
9 citations
TL;DR: Extensions of system conceptualisation models for autonomous vehicle storage and retrieval systems (AVS/RSs) to deal with non-exponential lift service times when the number of lifts and vehicles are both design variables based on an adaptation of a computational algorithm for estimating the probability distribution of queue lengths in capacitated, non-Poisson queuing systems.
Abstract: This paper proposes extensions of system conceptualisation models for autonomous vehicle storage and retrieval systems (AVS/RSs) to deal with non-exponential lift service times when the number of lifts and vehicles are both design variables. These extensions are based on an adaptation of a computational algorithm for estimating the probability distribution of queue lengths in capacitated, non-Poisson queuing systems. Simulation-based validation studies suggest that the proposed model extensions yield estimation errors comparable to those observed in earlier studies restricted to cases where the number of vehicle and lifts is treated as a single design variable.
5 citations
10 Oct 2011
TL;DR: The experience using the Unified Incident Command Decision Support System (UICDS) middleware platform developed by the U.S. Department of Homeland Security to facilitate sharing data between the authors' Real-Time Decision support System (RTDSS) and third party data sources is presented.
Abstract: This paper presents our experience using the Unified Incident Command Decision Support System (UICDS) middleware platform developed by the U.S. Department of Homeland Security to facilitate sharing data between our Real-Time Decision Support System (RTDSS) and third party data sources. We describe the basics of UICDS and further show how we integrated UICDS one of our projects.
4 citations
16 May 2011
TL;DR: iResTrac leverages the continuing penetration of smartphones in the hospital environment to provide medical, cleaning, and maintenance staff with an application that allows them to use a smartphone to scan barcodes to acquire and update information about resources.
Abstract: In this paper, we introduce iResTrac, a mobile device application and service-oriented architecture for capturing and retrieving hospital resource information such as beds or ventilators Our system leverages the continuing penetration of smartphones in the hospital environment to provide medical, cleaning, and maintenance staff with an application that allows them to use a smartphone to scan barcodes to acquire and update information about resources This solution does not require an additional hardware infrastructure like that required by RFID tags It uses existing hospital Wi-Fi infrastructure that allows the application to access an in-house web service that exposes methods to update and retrieve information In addition, the system provides a dashboard application that can be viewed in a traditional web browser or optimized for a tablet device
1 citations