Sir please explain me following code:

Question

Amanpreet Kaur 2015-10-28

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https://ww2.mathworks.cn/matlabcentral/answers/251390-sir-please-explain-me-following-code

评论： pardeep kaur 2020-9-7

%~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  DV-Hop Localization Algorithm  ~~~~~~~~~~~~~~~~~~~~~~~~
%~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
% BorderLength-----Side length of square regions, 
% NodeAmount-------The number of network nodes
% BeaconAmount--- Beacon nodes
% Sxy-------------- 3*NodeAmount matrix; (First row: Serial number for the
% nodes), (2nd & 3th row : their coordinates)
%%Beacon----------Beacon nodes coordinate matrix; BeaconAmount * BeaconAmount
%%UN-------------Unknown node coordinate matrix; 2 * UNAmount
%Distance------ distance matrix between Unknown nodes and beacon nodes  ;
%h---------------matrix of initial number of hops between nodes 
%X---------------Node estimates the coordinates of the initial matrix, X = [x, y]'
%R------------------Communication distance of node, typically 10-100m
clear,close all;
BorderLength=100;
NodeAmount=100;
BeaconAmount=8;
UNAmount=NodeAmount-BeaconAmount;
R=50;
h=zeros(NodeAmount,NodeAmount);  %The initial number of hops is 0; BeaconAmount row, NodeAmount column
X=zeros(2,UNAmount);%Estimated initial node coordinate matrix
%~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Generating uniformly distributed random topology within the square area~~~~~~~~~~~~~~~~~~~~
C=BorderLength.*rand(2,NodeAmount);%Coordinate of all nodes
Sxy=[[1:NodeAmount];C];
Beacon=[Sxy(2,1:BeaconAmount);Sxy(3,1:BeaconAmount)];%Beacon nodes coordinate
UN=[Sxy(2,(BeaconAmount+1):NodeAmount);Sxy(3,(BeaconAmount+1):NodeAmount)];%Unknown node coordinates
%Draw node distribution
plot(Sxy(2,1:BeaconAmount),Sxy(3,1:BeaconAmount),'r*',Sxy(2,(BeaconAmount+1):NodeAmount),Sxy(3,(BeaconAmount+1):NodeAmount),'k.');
xlim([0,BorderLength]);
ylim([0,BorderLength]);%Limitations of the area
title('* Red beacon nodes . Black unknown node')
%~~~~~~~~~~~~~~~~~~~~~~~~~~~~Creation of hops matrix~~~~~~~~~~~~~~~~~~~~~~
for i=1:NodeAmount
    for j=1:NodeAmount
        Dall(i,j)=((Sxy(2,i)-Sxy(2,j))^2+(Sxy(3,i)-Sxy(3,j))^2)^0.5;%Mutual distances between all nodes
        if (Dall(i,j)<=R)&(Dall(i,j)>0)
            h(i,j)=1;%The initial jump matrix
        elseif i==j
            h(i,j)=0;
        else h(i,j)=inf;% Dall(i,j) > R
        end
    end
end
%~~~~~~~~~~~~~~~~~~~~~~~~~Shortest path algorithm to compute node hops~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
for k=1:NodeAmount
    for i=1:NodeAmount
        for j=1:NodeAmount
            if h(i,k)+h(k,j)<h(i,j) %min(h(i,j),h(i,k)+h(k,j))
                h(i,j)=h(i,k)+h(k,j);
            end
        end
    end
end
h
%~~~~~~~~~~~~~~~~~~~~~~~~~Seeking school each beacon node positive~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
h1=h(1:BeaconAmount,1:BeaconAmount); 
D1=Dall(1:BeaconAmount,1:BeaconAmount);
for i=1:BeaconAmount
    dhop(i,1)=sum(D1(i,:))/sum(h1(i,:));%Average per each beacon node hop distance
end
D2=Dall(1:BeaconAmount,(BeaconAmount+1):NodeAmount);%BeaconAmount row UNAmount column
for i=1:BeaconAmount
    for j=1:UNAmount
        if min(D2(:,j))==D2(i,j)
            Dhop(1,j)=D2(i,j);%Unknown nodes obtained from the recent correction beacon
        end
    end
end
Dhop       % 1*UNAmount : distance from each unknown node to its nearest beacon node
%~~~~~~~~~~~~~~~~~~~~~~~~~~~Estimated distance with hops~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hop1=h(1:BeaconAmount,(BeaconAmount+1):NodeAmount)% BeaconAmount row* UNAmount column// Unknown number of beacon nodes to jump, 
for i=1:UNAmount
    hop=Dhop(1,i);%hop for the school obtained from the recent positive beacon
    Distance(:,i)=hop*hop1(:,i);%%UN Beacon row column;
end
% %~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Least squares method for determination of unknown point coordinates~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
d=Distance;
for i=1:2
    for j=1:(BeaconAmount-1)
      a(i,j)=Beacon(i,j)-Beacon(i,BeaconAmount);
    end
end
A=-2*(a');
% d=d1';
 for m=1:UNAmount 
     for i=1:(BeaconAmount-1)
         B(i,1)=d(i,m)^2-d(BeaconAmount,m)^2-Beacon(1,i)^2+Beacon(1,BeaconAmount)^2-Beacon(2,i)^2+Beacon(2,BeaconAmount)^2;
     end
           X1=inv(A'*A)*A'*B; % Least Square method
           X(1,m)=X1(1,1); % x coordinate
           X(2,m)=X1(2,1); % y coordinate
 end
 UN  %True coordinates of nodes
 X   %Estimated coordinates of nodes using DV-HOP
 for i=1:UNAmount
     error(1,i)=(((X(1,i)-UN(1,i))^2+(X(2,i)-UN(2,i))^2)^0.5);
 end
 figure;plot(error,'-o');
 title('Error of each unknown node');
 error=sum(error)/UNAmount;
 Accuracy=error/R;

4 个评论
显示 2更早的评论隐藏 2更早的评论

Walter Roberson 2015-10-28

Ingrid, you are definitely correct about "Sirs".

pardeep kaur 2020-9-7

hello maam

today i check your code. this is node localization by using DV-Hop algorithm. node localization is basically to find the coordinates of unknown nodes than are randomly deployed in the sensing area. Beacon nodes are GPS equipped nodes. this code is calculating localization error i.e. the difference in actual coordinates of any unknown nodes and estimated (or can say you have evaluted) coordinates.

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