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Diffstat (limited to 'paper/sections/model.tex')
| -rw-r--r-- | paper/sections/model.tex | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/paper/sections/model.tex b/paper/sections/model.tex index b478e94..acec974 100644 --- a/paper/sections/model.tex +++ b/paper/sections/model.tex @@ -192,7 +192,7 @@ Generalized Linear Cascade model with inverse link function $f:z\mapsto 1-e^{-\epsilon\cdot z}$. \subsubsection{Logistic Cascades} - +\label{sec:logistic_cascades} Consider the specific case of ``logistic cascades'' (where $f$ is the logistic function). This model captures the idea that there is a threshold around which each additional neighbor's contribution becomes significant: logistic @@ -201,10 +201,7 @@ Threshold model~\cite{Kempe:03}. As we will see later in the analysis, the Hessian of our optimization program simplifies in the case of a logistic inverse link function to $\nabla^2\mathcal{L}(\theta^*) = \frac{1}{|\mathcal{T}|}XX^T$ where $X$ is the observation matrix $[x^1 \ldots -x^\mathcal{|T|}]$. The (RE)-condition we introduce subsequently is then -equivalent to the assumption made in the Lasso analysis of~\cite{bickel:2009}. - - +x^\mathcal{|T|}]$. % \subsection{The Linear Threshold Model} @@ -234,10 +231,10 @@ equivalent to the assumption made in the Lasso analysis of~\cite{bickel:2009}. \begin{figure} \includegraphics[scale=.4]{figures/drawing.pdf} - \caption{Illustration of the sparse-recovery approach: the measurement matrix - is known, as is a Bernoulli realization of the matrix-vector product via the -non-linear transformation induced by $f$. Our objective is to recover the -unknown weight vector $\theta_i$ for each node $i$.} + \caption{Illustration of the sparse-recovery approach. Our objective is to + recover the unknown weight vector $\theta_j$ for each node $j$. We observe a +Bernoulli realization of the $f$ transform of the matrix-vector product, where +the measurement matrix encodes which nodes are ``contagious''} \end{figure} |
