X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/desynchronisation-controle.git/blobdiff_plain/120c13fc4faf264d8b1d3e94c4799860de9e3dea..e6cd9df3d469f7916d513610d3bc22ab055f790a:/IWCMC14/convexity.tex?ds=sidebyside diff --git a/IWCMC14/convexity.tex b/IWCMC14/convexity.tex index a663986..0f7bf7e 100644 --- a/IWCMC14/convexity.tex +++ b/IWCMC14/convexity.tex @@ -10,7 +10,7 @@ v_h^{(k)}.\dfrac{\ln(\sigma^2/D_h)}{\gamma p ^{2/3}} + \lambda_h^{(k)}p $. The function inside the $\arg \min$ is strictly convex if and only if $\lambda_h$ is not null. This asymptotic configuration may arise due to -the definition of $\lambda_i$. Worth, in this case, the function is +the definition of $\lambda_h$. Worth, in this case, the function is strictly decreasing and the minimal value is obtained when $p$ is the infinity. To prevent this configuration, we replace the objective function given @@ -25,7 +25,7 @@ in equation~(\ref{eq:obj2}) by In this equation we have first introduced new regularisation factors (namely $\delta_x$, $\delta_r$, and $\delta_p$) instead of the sole $\delta$. -This allows to further study the influence of each modification separately. +This allows to further separately study the influence of each factor. Next, the introduction of the rational exponent is motivated by the goal of providing a strictly convex function. @@ -38,10 +38,12 @@ $$ \begin{array}{rcl} f'(p) &=& -2/3.v_h.\dfrac{\ln(\sigma^2/D_h)}{\gamma p^{5/3}} + \lambda_h + 8/3.\delta_p p^{5/3} \\ -&& \dfrac {8/3.\delta_p p^{10/3} + \lambda_h p^{5/3} -2/3.v_h\ln(\sigma^2/D_h) }{p^{5/3}} +& = & \dfrac {8/3\gamma.\delta_p p^{10/3} + \lambda_h p^{5/3} -2/3.v_h\ln(\sigma^2/D_h) }{p^{5/3}} \end{array} $$ which is positive if and only if the numerator is. -Provided $p^{5/3}$ is replaced by $P$, we have a quadratic function which is strictly convex, for any value of $\lambda_h$. +Provided $p^{5/3}$ is replaced by $P$, we have a quadratic function +which is strictly convex, for any value of $\lambda_h$ since the discriminant +is positive. \ No newline at end of file