(Color online) The ESPPs with ϕ ( 1 ) > 0 for u 0 = 0.01 , σ = 0.25, μ =0.7, κ 1 = 20 , δ = 15, α = 0.5, κ 2 = 3.0 (dashed curve), κ 2 = 2.5 (solid curve), and κ 2 = 2.0 (dotted curve).