【正文】 ivity of the model has been analyzed under different situations.7) An optimal policy has been proposed according to the result of our model.8) Scalability is discussed in different situations.2 Assumption and Justification Basic Assumptions1) Terrain factor is out of other consideration.Reason: The terrain of the most regions referenced in the problem is flat. So it can be taken as a plane problem.2) Every refugee is regard as equivalentTeam49365 Page 24of 2525For office use onlyT1________________T2________________T3________________T4________________Team Control Number49365Problem ChosenFFor office use onlyF1________________F2________________F3________________F4________________2016 MCM/ICMSummary Sheet(Your team39。individuals except for their position and religion attributes.Reason: Human nature is nearly all the same. The desire to high ine and rest social environment and better welfare policy is similar to each other.3) Not every country will be included in this model. Only typical and crucial countries are selected in our model.Reason: There is nearly no refugees on certain routes out of position or other factors and the adjustment of policy won’t change this situation which means it means nothing for our model. Special Assumptions for different situations1) At the beginning of modeling, apart from the six routes mentioned in the question, we do not consider other routes that refugees may choose and assume all the refugee we will concerning choose one of the six routes.2) Second, at the beginning of modeling, we do not consider all the countries that have accepted the refugee, main countries producing refugees and main countries accepting refugees, such as Germany,France,Spain,Sweden,Afghan,Iran,Iraq,Syria,Turkey,Greece,Albania,Macedonia,Bulgaria,Rumania,Serbia,Montenegro,Bosnia,Croatia,Hungary,Austria,Ukraine,Slovakia,Czechoslovakia,Poland,Germany,France,Spain,Morocco,Italy,Libya,United Kingdom,Denmark,Norway,Sweden,Finland,Russia,Belgium,Holland and so on, other countries that the number of refugees produced or accepted is quite small are not being considered. Of course, there is no refugee who considers flowing to regions like America, Canada or China.3) The means of transportation assumed in our model are by highway, by railway, by shipping and by walking. And we make a simplification to let these means of transportation run at a certain rate, for example the miles that railway run per day. Besides, at the beginning of the model, we assume that there is no sudden accident.4) In our model, we assume that all refugees could reach the destination safe and sound.5) Assume that countries accepting refugees don’t change their refugee policy during the period of refugee crisis. 6) Assume every refugee move along the route straightly to reach the destination without detouring or changing the route.7) Assume the resources that supplied by every country accepting refugees are stable in a period, these resources will not increase because of refugee crisis or decrease because of the number of accepted refugee less than budgeted.8) Original model does not consider the influence of nongovernment agencies and only government takes the responsibility of accepting refugees.3 notationsIndicator of the degree of refugee crisisthe actual number of refugees on such a certain routefactor of transportation pressure of refugeesthe ideal number of refugees on such a certain routethe factor of resource consumption of refugeesthe number of all routesfactor of inequalitydegree of dangerfactor of overloadnumber of death people on the routesthe practical number of people on the routetimeconsuming indexthe allocation of refugees under the known condition without adjustmentoverloading indexthe allocation of refugees with the reasonable adjustment Total Capacity of i th countryThe number of the countries receiving refugees Annual economy increment *100 the money each country could provide to refugees Political factor the money each country could provide to refugees Welfare levelsexpense for each person. gdpthe total number of refugees Number of countries involvedthe total reasonable number of refugees Population of i th countrya/b/x/y/zPower index4 model overview Basic idea:A general indicatoris set up to indicate the degree of refugee crisis. The factor consists of two part: the transportation pressure indicator and resource consumption of refugees indicator. Each of the indicators above consists of more detailed factors which will be explained later. Bothandrepresent the degree of deviation between actual and theoretical value. So when thees to a minimum, it means the most rational condition according to the policies and economic and other factors.The actual conditions indicators can be calculated or estimated from the actual statistics, while the theoretical value can be solved according to the proceedings and formulas set up in the following sections.We can achieve two level of optimization procedures. The primary optimization: (without the adjustment of policies)The factors which can influence the primary optimization:1) Types of transportations, death rate of various routes, distance of various nodes of the simplified network, current nation policies and capacity, etc.2) The result of the primary optimization procedure indicates the most rational distribution of refugees on the links and the nodes of the network according to the current policies. The superior optimization:The factors which can influence the superior optimization:1) Types of transportations, death rate of various routes, distance of various nodes of the simplified network, the most rational nation policies and capacity