Modeling Social Interactions Between Households For Evacuation Behaviors In The Devasted Areas September 22nd, 2013 The University of TOKYO Doctoral course Junji URATA
Social Interactions’ examples are : In Daily Lives !    In Disasters ¦ - Drop and pick someone up  ¦  ¦ - Evacuate with others ¦ - Make joint purchase - - ' - Rescue ¦ - Patrol in neighborhood Social interactions help vulnerable traffic users in their daily lives Social interactions help people who can not evacuate on their own Objective: Modeling the mechanism of making social interactions Making to plan to evacuate quickly by group interactions 21
Problem1 : Why do people make social interactions? people take rational behaviors → choice their behaviors by depending on only their gain BUT choice their behavior for others →helpers’ utilities include helped people’s losses →Other-Regarding Preference 3
Problem2 : Who people make social interactions for? Social interactions pairs are made by one-to-one pairing BUT - if there are n people, the number of pairs is n(n-1)/2 - choice model of pairs have huge choice set →choice sets composed candidate pairs should be limited →Choice set generation 6 people →15 pairs 4
Choice set generation problem - form a pair of 2 people in all members Algorithm of Choice set generation Target all group members -Target all neighborhood group members (familiarity members) -Target easy recognition member outside neighborhood members non-compensatory choice set generation using influence of familiarity and recognition 5
Other-Regarding Preference problem Definition of Other-Regarding Preference by experimental economics (Fehr and Schmidt(1999)) Disutility as the difference of the gain of the opponent and gain their own u; = x; − α; · max{x; − x;,0}− β; · max{x; − x;,0}      (1) ui: the utility of player i   xi: the gain of player i α : a parameter if player i is helped    β : a parameter if player i help player j Inequality avoidance preference Making social interactions utility derive from Inequality avoidance - Making One-to-One pairs’ utility is composed by the difference of their gains. - The gains is defined by behavioral constraints 6
The utility is composed by the difference of their gains The gains is defined by behavioral constraints Utilities( ORij) from Other-Regarding Preference ai : Behavioral constraint gain (2) n : Explanatory factor  β : a parameter Occurrence Probability of Social Interaction pairs If pairs have common households, pairs’ observation errors are correlation → Cross Nested Logit model 7
upper nest: household, lower : pair G function Probability of pair k Abbe et al.(2007) (3) (4) Probability of household m (5) C : choice set M : the number of household Vk : the value of choice k μ m : scale parameter of household m μ : scale parameter of pair k ( 0 < μ < μ m) condition of allocation parameter o
About scale parameters
Conditions : 0 < μ < μ m Probability of pair k in household m (6)
About allocation parameters
A km：allocation parameter of pair k to household m Hypothesis : Degree of allocation is different ! If the upper nests’ scale parameters are larger, probability of pair k is larger i from helper and helped in eq.6 if the value of Vk is large ω : dummy of helped CASE STUDY -Social Interactions under disasters- 9.
•Two disasters were caused by typhoons on August 18 and September 29 in 2004 The August typhoon •a maximum rainfall of 55mm per hour •Mudslides left 3 people dead The September typhoon •281mm of rainfall •Mudslides left 5 people dead
Survey(2004.9-10) •Surveyed residents’ bahaviors during these disasters by interviews (Oral communication) •Interviewed them about their awareness of the danger, risk management behaviors, and cooperation behaviors •Cooperative behaviors include rescuing others, evacuating with others, accommodating evacuees, meeting and exchanging information.
Network
•Nodes show households •Links show cooperative behaviors between the households 11
the value function of pair ij Other-Regarding        Other-Regarding    making cost V ij,t = β dam |dam i,t = dam j,t |+ β old |old i,t = old j,t |+ β a d ij + βρeιο (belo; + belo ; )+ βαbabzone;j + βresRs;j (9) Table 1  The list of variables
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than C, D.
Table 2  The estimation result
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Future works
- Formulated the occurrence of social interactions by other-regarding preferences and estimated using the behavior data of the mudslide and heavy rain disaster. - The utilities of other-regarding preferences defined as the difference of their own gain and the gains of others. - The occurrence probabilities of social interactions are shown by a cross nested logit model. - The utilities of the other-regarding preferences are composed by the behavioral constraints of the households and there are the correlations of the error term among the pairs including the same households.
Future works
-  Introduce the behavioral choice models the time transitions.  Many people will be acting in anticipation of the future disasters. - Choice set generation algorithm need improvement by compensatory method. 17 Thank you for your listening. 18