X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/desynchronisation-controle.git/blobdiff_plain/17a131a2d00611e1582103549a9c7d2bac2be03e..ae93ee0d91e2a8f31ec45f7b77f9e81294630f07:/IWCMC14/convexity.tex diff --git a/IWCMC14/convexity.tex b/IWCMC14/convexity.tex index a663986..172ca37 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 @@ -20,12 +20,12 @@ in equation~(\ref{eq:obj2}) by \delta_x \sum_{h \in V, l \in L } x_{hl}^2 + \delta_r\sum_{h \in V }R_{h}^2 + \delta_p\sum_{h \in V }P_{sh}^{\frac{8}{3}}. -\label{eq:obj2} +\label{eq:obj2p} \end{equation} 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 @@ $$ \begin{array}{rcl} f'(p) &=& -2/3.v_h.\dfrac{\ln(\sigma^2/D_h)}{\gamma p^{5/3}} + \lambda_h + 8/3.\delta_p p^{5/3} \\ -&& \dfrac {8/3.\delta_p p^{10/3} + \lambda_h p^{5/3} -2/3.v_h\ln(\sigma^2/D_h) }{p^{5/3}} +& = & \dfrac {8/3.\delta_p p^{10/3} + \lambda_h p^{5/3} -2/3\gamma.v_h\ln(\sigma^2/D_h) }{p^{5/3}} \end{array} $$ 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