Note—Some Equivalent Objectives for Dynamic Network Flow Problems

Jarvis, John J.; Ratliff, H. Donald

doi:10.1287/mnsc.28.1.106

Cited by 102 publications

(55 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…By computing a MDF for each source to the sink, Hajek and Ogier, (1984) solve a special case of continuous QF problem with multi-sources, a single-sink, and zero travel times on the arcs. A result in (Philpott, 1990) extends the results of (Anderson et al 1982) to arbitrary travel times and presents triple optimization results of MDF, QF and minimizing the total egress time, similar to discrete approach given in (Jarvis and Ratliff, 1982). The generalized cut capacity bounds the value of the continuous flow, (Philpott, 1990).…”

Section: Continuous Flows Over Timementioning

confidence: 68%

Significance of Transportation Network Models in Emergency Planning of Cities

Dhamala

Pyakurel

2016

CPP

View full text Add to dashboard Cite

Transportation network models within the framework of operations research have been established as one of the emerging field of research frontiers in today's very disastrous life and dense traffic system. The discrete as well as continuous flow over time models have been widely considered by social, engineering and applied scientists with wide varieties of real-life problems, like rush hour traffic and traffic management at the time of any disaster. Among the PPRR classification issues, the concentration will be given within the planning approach with transportation networks for urban cities.We present the models and solution strategies of the transportation networks that are dynamic in nature and directly apply in rush hour traffic or human-made or natural disasters in the urban cities. The difficulty levels of the varieties of algorithms, efficiencies of their solution software and the significance of the obtained solutions for the betterment of modern city plan are discussed with wide spectrum of model diversity. Among many others, we illustrate, also supporting with a case study, the impact of recent Nepal Earthquake 2015 and the meaningfulness of effective evacuation planning for saving the property and people in urban city like, Kathmandu, valley.The high performance of the technique of lane reversals in transportation or evacuation networks which has already been adopted a lot in practice, but has been analytically studied only recently are focused in this paper. Adopted this dynamic transportation strategy, the flow in the transportation can be doubled, the time can be saved significantly and many transportation arcs can be utilized for logistic supports or for emergency vehicles whenever necessary. Improved results are presented and the importance of integrated models dependent on time and vehicles is explored. The optimal solution thus obtained with contraflow, logistic supports and facility location at appropriate positions of transportation network proves the significance of these models in emergency planning.

show abstract

Section: Continuous Flows Over Timementioning

confidence: 68%

Significance of Transportation Network Models in Emergency Planning of Cities

Dhamala

Pyakurel

2016

CPP

View full text Add to dashboard Cite

show abstract

“…Jarvis and Ratliff have shown that a flow meeting Objective 12 is equivalent to UQF (25); however, their proof relied on the Ford-Fulkerson algorithm and thus was limited to a single-source, single-sink network with time-invariant parameters (18). The following general approach shows that this proposition is true even in a network with multiple sources and time-varying parameters.…”

Section: Here B Imentioning

confidence: 94%

Modeling of Evacuation and Background Traffic for Optimal Zone-Based Vehicle Evacuation Strategy

Zheng

Chiu

Mirchandani

et al. 2010

Transportation Research Record: Journal of the Transportation R

View full text Add to dashboard Cite

Supply-demand interaction is a challenge that must be considered in no-notice evacuation modeling. It is quite common that during an evacuation event, demand is much greater than supply for an extended time period, resulting in severe and prolonged traffic congestion. The severity and temporal extent of such congestion cannot be estimated by simple calculation because of the traffic flow phenomenon in which the traffic throughput is much less than the nominal capacity under severe congestion. Even more, evacuees change their decisions before or during evacuation in response to various traffic management strategies, such as radio and message sign information or contraflow lanes and improved signal control. Once the traffic management decisions are modified, the traffic demand on various evacuation routes would change, as does the congestion resulting from this new demand-supply interaction.The system performance of such an interaction can be properly captured through a descriptive traffic simulation model combined with a prescriptive optimization model for the evacuation strategies. The selection and implementation of no-notice evacuation strategies need to be driven by one or several system objectives. In the prescriptive concept, the best possible strategy is then established through a system optimization approach.Most traditional prescriptive models use only static flow without considering vehicular flow dynamics, such as shock wave propagation or queue formation and dissipation. In recent years, the cell transmission model (CTM) (1) has been used as part of the system-optimal (SO) dynamic traffic assignment (DTA) method (2) in several evacuation studies (3,4), to determine the multidimensional optimal decisions simultaneously, including evacuees' departure time, destination, and route choices (5).The "information" component is another important element that needs to be properly captured in evacuation modeling. Chiu and Mirchandani studied the attributes of information affecting evacuation route choice and demonstrated how to use information to influence evacuees' route choice to reach the SO state (6). Furthermore, disasterand evacuation-related information available through various information dissemination channels to both evacuees and nonevacuees can affect their decisions before and during the evacuation. For example, information about the blockage or closure of a certain area would result in the diversion of nonevacuees who originally intend to traverse the (now-closed) hot zone. Nonevacuees are also likely to synthesize the closure information and past experience to determine their own best alternative route. Such critical aspects of information have not been well addressed in the literature for no-notice evacuation scenarios.The main technical contributions of this study are twofold. First, a simulation-optimization framework is proposed in which a universal quickest flow (UQF)-also known as the earliest arrival flow Modeling of Evacuation and Background Traffic for Optimal Zone-Based Vehicle Evacuatio...

show abstract

“…The transport utilization condition supersedes the previous constraint, resulting in five total constraints as shown in Eq. (12). The constraints require that exploration utilization is allowed for transports having identical destinations and arrivals before the demands are needed (constraints 1 and 2), transportation utilization is only allowed within a transport (constraint 3), and resource transfer is allowed for transports arriving and departing from identical nodes where the arrival occurs before the departure (constraints 4 and 5).…”

Section: B Modeling Cargo Manifestsmentioning

confidence: 99%

“…A time-expanded flow network enables analysis by reformulating the dynamic network as a series of static networks at each time step [11][12][13]. The extensive literature and tools of graph theory can then be applied to obtain insights into the exploration system problem, including new methods to establish feasibility and visual companions to matrices.…”

Section: Flow Network Graph Formulationmentioning

confidence: 99%

Matrix Methods for Optimal Manifesting of Multi-Node Space Exploration Systems

Grogan¹,

Siddiqi²,

Weck³

2010

AIAA SPACE 2010 Conference &Amp; Exposition

View full text Add to dashboard Cite

This paper presents matrix-based methods for determining optimal cargo manifests for space exploration. An exploration system is defined as a sequence of in-space and on-surface transports between multiple nodes coupled with demands for resources. The goal is to maximize value and robustness of exploration while satisfying logistical demands and physical constraints at all times. To reduce problem complexity, demands are abstracted to a single class of resources and one metric (e.g. mass or volume) governs capacity limits.

show abstract

Note—Some Equivalent Objectives for Dynamic Network Flow Problems

Cited by 102 publications

References 0 publications

Significance of Transportation Network Models in Emergency Planning of Cities

Significance of Transportation Network Models in Emergency Planning of Cities

Modeling of Evacuation and Background Traffic for Optimal Zone-Based Vehicle Evacuation Strategy

Matrix Methods for Optimal Manifesting of Multi-Node Space Exploration Systems

Contact Info

Product

Resources

About