scholarly journals Abstract Contraflow Models and Solution Procedures for Evacuation Planning

2018 ◽  
Vol 10 (4) ◽  
pp. 89
Author(s):  
Ram Chandra Dhungana ◽  
Urmila Pyakurel ◽  
Tanka Nath Dhamala
Keyword(s):  
Efficient Solution ◽  
Flow Model ◽  
Efficient Algorithms ◽  
Evacuation Planning ◽  
Flow Paths ◽  
Evacuation Time ◽  
Solution Approach ◽  
Switching Property ◽  
Risk Areas

The abstract flow model deals with the flow  paths (routes) that satisfy the switching property. Contraflow is a widely accepted solution approach that increases the flow and decreases the evacuation time making the traffic smooth during evacuation by reversing the required road directions from the risk areas to the safe places. In this paper, we integrate the concepts of abstract flow and contraflow, give mathematical formulations of these models and present efficient algorithms for solving the abstract contraflow problems. The efficient solution procedures are presented for  maximum dynamic, lexicographically maximum and earliest arrival abstract contraflow  problems. This approach maximizes the flow value in given time and seeks to eliminate the crossing conflicts.

scholarly journals Abstract Contraflow Models and Solution Procedures for Evacuation Planning

2018 ◽  
Vol 10 (4) ◽  
pp. 88 ◽  
Author(s):  
Ram Chandra Dhungana ◽  
Urmila Pyakurel ◽  
Tanka Nath Dhamala
Keyword(s):  
Efficient Solution ◽  
Flow Model ◽  
Efficient Algorithms ◽  
Evacuation Planning ◽  
Flow Paths ◽  
Evacuation Time ◽  
Solution Approach ◽  
Switching Property ◽  
Risk Areas

The abstract flow model deals with the flow  paths (routes) that satisfy the switching property. Contraflow is a widely accepted solution approach that increases the flow and decreases the evacuation time making the traffic smooth during evacuation by reversing the required road directions from the risk areas to the safe places. In this paper, we integrate the concepts of abstract flow and contraflow, give mathematical formulations of these models and present efficient algorithms for solving the abstract contraflow problems. The efficient solution procedures are presented for  maximum dynamic, lexicographically maximum and earliest arrival abstract contraflow  problems. This approach maximizes the flow value in given time and seeks to eliminate the crossing conflicts.

scholarly journals Efficient Solution Approach to Maximum Flow Evacuation Planning Problem without Flow Conservation Aspect

2018 ◽  
Vol 13 (1) ◽  
pp. 108-116
Author(s):  
Phanindra Prasad Bhandari ◽  
Shree Ram Khadka
Keyword(s):  
Network Flow ◽  
Efficient Solution ◽  
Maximum Flow ◽  
Evacuation Planning ◽  
Planning Problem ◽  
Intermediate Node ◽  
Solution Approach ◽  
Solution Strategies ◽  
Source Sink ◽  
Flow Conservation

 An attempt of shifting as more people as possible and/or their logistics from a dangerous place to a safer place is an evacuation planning problem. Such problems modeled on network have been extensively studied and the various efficient solution procedures have been established. The solution strategies for these problems are based on source-sink path augmentation and the flow function satisfies the flow conservation at each intermediate node. Besides this, the network flow problem in which flow may not be conserved at node necessarily could also be used to model the evacuation planning problem. This paper proposes a model for maximum flow evacuation planning problem on a single-source-single-sink static network with integral arc capacities with holding capability of evacuees in the temporary shelter at intermediate nodes and extends the model into the dynamic case. Journal of the Institute of Engineering, 2017, 13(1): 108-116

scholarly journals Abstract Earliest Arrival Transshipment with Network Reconfiguration

2018 ◽  
Vol 35 (1-2) ◽  
pp. 1-9
Author(s):  
Ram Chandra Dhungana ◽  
Tanka Nath Dhamala
Keyword(s):  
Network Flow ◽  
Flow Model ◽  
Dynamic Network ◽  
Flow Paths ◽  
Optimal Flow ◽  
Switching Property ◽  
Efficient Approximation Algorithm ◽  
Np Complete ◽  
Efficient Approximation ◽  
Time Point

The abstract flow model is the generalization of network flow model which deals with the flow paths (routes) satisfying the switching property. Contraflow model increases the flow value by reversing the required arc directions from the sources to the sinks. In this paper, we integrate the concepts of abstract flow and contraflow to introduce abstract earliest arrival transshipment contraflow model in multi-terminal abstract network. The abstract contraflow on multi-terminal dynamic network is NP-Complete. We present an efficient approximation algorithm to solve the problem. This approach satisfies the demand of sinks by sending optimal flow at every possible time point and seeks to eliminate the crossing conflicts.

A novel crowd flow model based on linear fractional stable motion

2016 ◽  
Vol 30 (09) ◽  
pp. 1650049 ◽  
Author(s):  
Juan Wei ◽  
Hong Zhang ◽  
Zhenya Wu ◽  
Junlin He ◽  
Yangyong Guo
Keyword(s):  
Flow Rate ◽  
Flow Model ◽  
Threshold Value ◽  
Evacuation Time ◽  
Indoor Space ◽  
Stable Motion ◽  
Crowd Density ◽  
Linear Fractional Stable Motion ◽  
Positive Correlations ◽  
Fractional Stable Motion

For the evacuation dynamics in indoor space, a novel crowd flow model is put forward based on Linear Fractional Stable Motion. Based on position attraction and queuing time, the calculation formula of movement probability is defined and the queuing time is depicted according to linear fractal stable movement. At last, an experiment and simulation platform can be used for performance analysis, studying deeply the relation among system evacuation time, crowd density and exit flow rate. It is concluded that the evacuation time and the exit flow rate have positive correlations with the crowd density, and when the exit width reaches to the threshold value, it will not effectively decrease the evacuation time by further increasing the exit width.

scholarly journals Evaluation of tsunami evacuation planning of the primary school student in Padang

2019 ◽  
Vol 276 ◽  
pp. 02018
Author(s):  
Yosritzal ◽  
Badrul Mustafa Kemal ◽  
Mahdhivan Syafwan ◽  
Junaidi ◽  
Hasdi Putra ◽  
...  
Keyword(s):  
Elementary School ◽  
Disaster Management ◽  
School Children ◽  
Elementary School Children ◽  
Walking Speed ◽  
Evacuation Planning ◽  
Observation Data ◽  
Evacuation Time ◽  
Primary School Student ◽  
Evacuation Experiment

This paper presents an evaluation of the tsunami evacuation of elementary school children in Padang. The objective of the study is to evaluate the evacuation planning using an observation data from an evacuation Experiment initiated by the Padang Regional Disaster Management Agency (BPBD Padang). In this study, the chosen evacuation destination was evaluated based on the available evacuation time, the evacuation methods, walking speed of the students in a group and the provided tools in the classroom for evacuation as in the guidelines of tsunami evacuation for schools in Hawaii.

scholarly journals Non-conserving Flow Aspect of Maximum Dynamic Flow Problem

2018 ◽  
Vol 14 (1) ◽  
pp. 107-114
Author(s):  
Phanindra Prasad Bhandari ◽  
Shree Ram Khadka
Keyword(s):  
Network Flow ◽  
Efficient Solution ◽  
Flow Problem ◽  
Dynamic Network ◽  
Maximum Flow ◽  
Solution Procedure ◽  
Evacuation Planning ◽  
Planning Problem ◽  
Intermediate Node ◽  
Flow Conservation

Shifting as many people as possible from disastrous area to safer area in a minimum time period in an efficient way is an evacuation planning problem (EPP). Modeling the evacuation scenarios reflecting the real world characteristics and investigation of an efficient solution to them have become a crucial due to rapidly increasing number of natural as well as human created disasters. EPPs modeled on network have been extensively studied and the various efficient solution procedures have been established where the flow function satisfies the flow conservation at each intermediate node. Besides this, the network flow problem in which flow may not be conserved at nodes necessarily could also be useful to model the evacuation planning problem. This paper proposes an efficient solution procedure for maximum flow evacuation planning problem of later kind on a single-source-single-sink dynamic network with integral arc capacities with holding capability of flow (evacuees) in the temporary shelter at intermediate nodes. Journal of the Institute of Engineering, 2018, 14(1): 107-114

OBNOXIOUS FACILITY LOCATION: COMPLETE SERVICE WITH MINIMAL HARM

2000 ◽  
Vol 10 (06) ◽  
pp. 581-592 ◽  
Author(s):  
BOAZ BEN-MOSHE ◽  
MATTHEW J. KATZ ◽  
MICHAEL SEGAL
Keyword(s):  
Data Structure ◽  
Facility Location ◽  
Efficient Solution ◽  
Location Problem ◽  
Facility Location Problem ◽  
Efficient Algorithms ◽  
Minimal Distance ◽  
Rectangular Region ◽  
Obnoxious Facility Location ◽  
Obnoxious Facility

We present efficient algorithms for several instances of the following facility location problem. Place k obnoxious facilities, with respect to n given demand sites and m given regions, where the goal is to maximize the minimal distance between a demand site and a facility, under the constraint that each of the regions must contain at least one facility. We also present an efficient solution to the following planar problem that arises as a subproblem. Given n transmitters, each of range r, construct a compact data structure that supports coverage queries, i.e., determine whether a query polygonal/rectangular region is fully covered by the transmitters.

scholarly journals Crisis hazard assessment for snow-related lahars from an unforeseen new vent eruption: the 2018 eruption of Kusatsu-Shirane volcano, Japan

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Kyoko S. Kataoka ◽  
Kae Tsunematsu ◽  
Takane Matsumoto ◽  
Atsushi Urabe ◽  
Katsuhisa Kawashima
Keyword(s):  
Hazard Assessment ◽  
Flow Model ◽  
Hot Springs ◽  
Snow Water Equivalent ◽  
Hazard Zonation ◽  
Linear Relationships ◽  
Input Parameters ◽  
Snow Water ◽  
Risk Areas ◽  
Hazard And Risk

AbstractTwo-thirds of the 111 active volcanoes in Japan are covered with snow for several months during winter and demonstrate high hazard and risk potentials associated with snow-related lahars during and after eruptions. On 23 January 2018, a sudden phreatic eruption occurred at the ski field on Kusatsu-Shirane (Mt. Motoshirane) volcano, Japan. This new vent eruption from the snow-clad pyroclastic cone required forecasting of future snow-related lahars and crisis hazards zonation of downslope areas including Kusatsu town, a popular tourist site for skiing and hot springs. In order to achieve a prompt hazard assessment for snow-related lahars, a multidisciplinary approach was carried out involving characterization of proximal tephra deposits, snow surveys, and numerical lahar flow simulations using the Titan2D model. To determine the input parameters for the flow model, the consideration of snow water equivalent (SWE) immediately after the eruption (on 29 January) and in the post-eruptive period (on 12 March), was significant. In the case of Kusatsu-Shirane volcano during the winter of 2018, linear relationships between altitude and SWE, obtained at different elevations, were used to estimate the snow volume around the new vents. Several scenarios incorporating snow and snowmelt (water), with or without the occurrence of a new eruption, were simulated for the prediction of future lahars. Three lahar scenarios were simulated, including A) rain-on-snow triggered, B) ice/snow slurry, and C) full snowmelt triggered by a new eruption, and indicated the flow paths (inundation areas) and travel distances. These were useful for lahar hazard zonation and identification of potential high-risk areas. Since the input parameters required for the Titan2D flow model can be relatively easily determined, the model was suitable for the 2018 eruption at Motoshirane where historical and geological lahar records are not available for calibration. The procedure used in the study will enable rapid lahar prediction and hazard zonation at snow-clad volcanoes. Further consideration for simulating a cohesive-type flow, which was predicted by the primary deposits containing large amounts of clay minerals and could not be expressed in the Titan2D flow model, is necessary.

A Simplified ‘Effective Circuit’ Fluid Flow Model for Forced Convection in Oblique Fin Configuration

2014 ◽  
Author(s):  
Nasi Mou ◽  
Poh Seng Lee ◽  
Saif A. Khan
Keyword(s):  
Fluid Flow ◽  
Mass Flow ◽  
Flow Model ◽  
Electrical Circuit ◽  
Flow Paths ◽  
Micro Channels ◽  
Discrete Flow ◽  
Actual Flow ◽  
The Difference ◽  
Full Domain

In this paper, a simplified ‘effective circuit’ fluid flow model is proposed to complement full-domain (geometry based) simulations of fluid flow in novel discrete oblique fin heat sinks. In the proposed model, the discrete flow paths are modeled as effective resistances, and the intersections between discrete flow paths are modeled as ‘nodes’. In an electrical circuit, the current of each branch can be derived from the current division rule, and hence the actual flow rates in the effective circuit are determined by the effective resistances. Simulink R2011b, a graphical extension to MATLAB for modeling and simulation of systems, is chosen to construct the equivalent circuit. The effective resistances are calculated using the well-known friction factor expressions for laminar flow in micro-channels. A full-domain geometry-based simulation is performed on CFX 14.0 serving as a benchmark for the developed ‘effective circuit’ fluid flow model. The results show that for a given total current value and mass flow rate, the difference of pressure drop over the whole heat sink between the simplified flow model and CFX simulation is within 13%. The mass flow distributions obtained from the simplified flow model and the CFX simulation exhibit a common distribution pattern. Interestingly, the simplified flow model is even able to capture flow migration — a distinctive phenomenon of flow in oblique fin geometries. We thus confirm the feasibility of the method of construction of our simplified ‘effective circuit’ fluid flow model.

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