Skip to main content
. 2022 Feb 15;159:102598. doi: 10.1016/j.tre.2021.102598

Table A.1.

Nomenclature; list of sets, indices, parameters, and decision variables.

Symbol Definition Symbol Definition
.EC Suffix for excessive capacity of related variable; .ID Suffix for location ID of population of related variable;
.Pop Suffix for population of related variable; .Pos.SC Position (chromosome) of particle in a shortage strategy;
.Quality The quality (fitness) of the particle (individual); .R Suffix for the initial results;
.TDist Suffix for total distance of related variable; .Tpop Suffix for total population of related variable;
α Probability rate of Monte Carlo selection process; AA Set of assigned demand points (equal to X decision variable of
Assignement model);
AD Set of Average distance of demands and allocated VCs ; ALT.ID Set of IDs of the available VCs from the current position of truck v;
ALT.T Set of travel times to available VCs from the current position of truck v; ASS Demand assignment of day d to VCs;
Avv Truck availability for next destination; binary parameter; AVC Set of numbers of active vaccine centres;
BASS Balanced capacity assignment of the service centres ; BC Maximum movements in staff re-allocation;
BD Balanced distribution; Bofparticle The particle with best quality (fitness) in the last set of particles;
Bofswarm The particle with overall best quality (fitness); C Assigned capacity of VCs in the ASSd for simulation;
Ci Allocated capacity to the centre i; C1 A random coefficient number in Delta in Alg. XI;
CC Set of Original capacities of the VC; CCT Current capacity of vaccine distribution ;
CD Capacity difference; Chr Chromosome;
Clients Set of numbers (ID) of the pre allocated Demands to a centre; Costij The distance between centre i to centre j;
CRSd Couriers distribution of day d within time window tw; Currentcost Unchanged cost in process of the Alg. IX;
d Counter for vaccination day; dij The Euclidean distance between centre j and demand i;
Ds Set of coordinates of Demand point s; D1 A random coefficient number in Vcurrent in Alg. XI;
DCD Dynamic capacity difference; Delta Distance of particle from Bofparticle and Bofswarm;
DEV Difference of centres’ capacity from constraint; Diffi Remaining capacity of VCsi;
DIS Set of distances from allocated demand points to a centre; Dist Distance between the demand and VCs;
Distmatrixij The Euclidean distance between centre j and demand i; DM Decision maker;
DPopi Population of the demand point i (in each day d) ; DST ID number of the next destination of truck v in day d;
DT Central vaccine storage place (depot); DV Delivered vaccines to VCs in day d;
Elite Individual with the least amount of fitfuncion; ET Expiration time of vaccine packages;
Excess Excessive load; FD Set of locations’ IDs with no unmet demand;
fit Fitness ; g Counter for offsprings of the crossover;
j, j index of demand points; IDC ID number of VCs;
IFC Individual for crossover; IFM1 Selected particles for muting by mutation 1;
IFM2 Selected particles for muting by mutation 2; IND Set of IDs (numbers) of centre corresponding the allocating
demands point;
int Interval gap for receiving second dose of vaccine; k Counter for demands for the assignment model;
Lv Load of vehicle v; Local Prefix for local variables (Set of demand points temporary
allocated to VCs);
LV Levelled capacity of VC; Set of IDs (numbers) of the VCs;
MC Maximum capacity of VC; Mutant1 The individual that has been muted by mutation 1;
Mutant2 The individual that has been muted by mutation 2; N Set pf Population of IDs of demands for assignment model;
N Set of IDs (numbers) of the Demand points; nc Number parent particles for crossover;
NG Next generation of results; nIteration Number of iteration for the GA;
NM Nominated VCs for serving demand; nm1 Number of individuals to get mutated by the mutation 1;
nm2 Number of individuals to get mutated by the mutation 2; NoT Number of trucks in day d to distribute vaccines;
npop Population of initial results in HGA Alg.s; OC Overall capacity of VCs;
Offs VCs with zero overall capacity; Offspring1 The first child of parent 1 and parent 2;
Offspring2 The second child of parent 1 and parent 2; OP Over populated centres;
PNew New received package; Pd Package of vaccines of day d;
Pr Reserved vaccines; Parent1 The individual that is a parent for the crossover;
Parent2 Another individual for parenting in the crossover; Particlei The particle I in the swarm;
pc Chance of being parent for the individuals in a generation; PDCD Peak dynamic capacity difference;
pm1 Mutation probability rate 1; pm2 Mutation probability rate 2;
Popi The individual i in the generation; Prio Priority ranking of mesh block area centroid;
Queue Set of demand points’ IDs waiting for vaccination of the day; R Distance between all the demands and their nearest centre;
Ratio Accuracy measure index; RC Remaining capacity;
Rs Euclidean distance between demand and nearest centre; S The number of supply for the assignment model;
s A counter for centres; SiSeq Set of vaccine distribution sequences;
Scorek Chance of selecting centre k in the chromosome; Shortage Shortage load;
SQv Set of sequence of truck v visiting VCs; SRw Surplus population in overpopulation VCs of w(iteration);
ST1 Set of demands’ numbers as Service takers (first dose vaccination); ST2 Set of demands’ numbers as Service takers (second
dose vaccination);
t A counter for demand points; TCC Total centres capacity;
TDC Total capacity difference; TMC Total maximum capacity of VCs;
TPD1 Top priority demand layer 1 (first dose vaccination); TPD2 Top priority demand layer 2 (second dose vaccination);
TS Vehicle (truck) capacity; TTv Travel time of truck v from current VC to the next VC;
TW Time window for vaccine delivery; U A Boolean variable to terminate the loop in the Alg. IX;
UC Undelivered vaccine demand of VCs; UC OC that can change during the process of Alg. IX;
UF1 Set of not working with full of excess capacity centres; v Index of couriers trucks;
v A counter for the trucks; Vcurrent current speed for changing;
Vpast Speed of changing in the last generation; VCk.Tdist Total distance of the allocated demands to the centre k;
VCk.Tpop Total population of the allocated demands to the centre k; VCl Vaccine centre’s load;
VDCD Valley dynamic capacity difference; VR vehicle sequence with minimum travel time;
Wj Population of the assigned demand point i; Winner Index of the centre that has been selected for muting;
WLD2d Set of number of demands as waiting list (second dose vaccination) on day d; Xij Allocated population of point j to centre i;
Xk Decision variable of the assignment model; XX Sum of chromosomes with less excess amount;
Y.d1 Total maximum daily required demand for dose 1; Y.d2 Total maximum daily required demand for dose 2;
YY Sum of chromosomes with less shortage amount; z A counter for crossover operation;
ZMB Number of allowed set of destinations collection; ZT Vaccine expiration threshold;