public AnonymizedLocation Anonymize(OriginalLocation msc)
{
SimulateOtherUsers(msc); //Only for the purpose of this prototype. Remove for video
var n = AddMessage(msc);
var gmMark = _gm.SubGraph(n);
var m = LocalKSearch(msc.K, msc, gmMark).ToList();
if (!m.Any())
{
return(null);
}
_im.Remove(msc);
_hm.Remove(msc);
_gm.RemoveNode(msc);
var bbox = Mbr(m);
//TODO: Remove for video
_im = new MultidimensionalIndex();
_hm = new ExpirationHeap();
_gm = new ConstraintGraph();
return(new AnonymizedLocation
{
Id = msc.Id,
LatMin = bbox.MinX,
LatMax = bbox.MaxX,
LonMin = bbox.MinY,
LonMax = bbox.MaxY
});
}
public ConstraintGraph SubGraph(IEnumerable <OriginalLocation> n)
{
var result = new ConstraintGraph();
foreach (var node in _nodes.Where(node => n.Contains(node.Message)))
{
result.AddNode(node.Message);
foreach (var edge in node.Edges.Where(edge => n.Contains(edge.To)))
{
result.AddEdge(edge.From, edge.To);
}
}
return(result);
}
private static IEnumerable <OriginalLocation> LocalKSearch(int k, OriginalLocation msc, ConstraintGraph gmMark)
{
var u = gmMark.Nbr(msc).Where(ms => ms.K <= k).ToList();
if (u.Count() < k - 1)
{
return(new List <OriginalLocation>());
}
var l = 0;
while (l != u.Count())
{
l = u.Count();
foreach (var ms in new List <OriginalLocation>(u))
{
if (gmMark.Nbr(ms).Count() < k - 2)
{
u.Remove(ms);
gmMark.RemoveNode(ms);
}
}
}
return(gmMark.FindClique(msc, k));
}
