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| author | jeanpouget-abadie <jean.pougetabadie@gmail.com> | 2015-03-11 11:57:27 -0400 |
|---|---|---|
| committer | jeanpouget-abadie <jean.pougetabadie@gmail.com> | 2015-03-11 11:57:27 -0400 |
| commit | 0b13f28fa5d0ae2731c12cba5f432a3e5232c47e (patch) | |
| tree | b7b18aade3a582b63d6e0b26d3014410f1a53f91 /presentation | |
| parent | a57f6611e811820eb618ef6538792a43812418bc (diff) | |
| download | cascades-0b13f28fa5d0ae2731c12cba5f432a3e5232c47e.tar.gz | |
fixed typos
Diffstat (limited to 'presentation')
| -rw-r--r-- | presentation/stats/beamer_2.tex | 37 |
1 files changed, 19 insertions, 18 deletions
diff --git a/presentation/stats/beamer_2.tex b/presentation/stats/beamer_2.tex index ecc66ed..258b099 100644 --- a/presentation/stats/beamer_2.tex +++ b/presentation/stats/beamer_2.tex @@ -62,17 +62,17 @@ What do we know? What do we want to know? \begin{itemize} \item At $t=0$, nodes are in three possible states: susceptible, {\color{blue} infected}, {\color{red} dead} -\pause + \item At time step $t$, each {\color{blue} infected} node $i$ has a ``one-shot'' probability $p_{i,j}$ of infecting each of his susceptible neighbors $j$ at $t+1$. -\pause + \item A node stays {\color{blue} infected} for one round, then it {\color{red} dies} -\pause -\item At $t=0$, each node is {\color{blue} infected} with probability $p_{\text{init}}$ -\pause + +\item At $t=0$, each node is {\color{blue} infected} with probability $p_{\text{init}}$ and susceptible with probability $1-p_{\text{init}}$ + \item Process continues until random time $T$ when no more nodes can become infected. -\pause + \item $X_t$: set of {\color{blue} infected} nodes at time $t$ -\pause + \item A {\bf cascade} is an instance of the ICC model: $(X_t)_{t=0, t=T}$ \end{itemize} @@ -112,7 +112,7 @@ What do we know? What do we want to know? \begin{itemize} \item If the {\color{orange} orange} node and the {\color{green} green} node are infected at $t=0$, what is the probability that the {\color{blue} blue} node is infected at $t=1$? -$$1 - \mathbb{P}(\text{not infected}) = 1 - (1 - .45)(1-.04)$$ +$$1 - \mathbb{P}(\text{not infected}) = 1 - (1 - .72)(1-.04)$$ \end{itemize} @@ -139,7 +139,7 @@ $$\mathbb{P}(j \text{ becomes infected at t+1}|X_{t}) = 1 - \prod_{i \in {\cal N \begin{frame} \frametitle{Independent Cascade Model} -For each susceptible node $j$, the event that it becomes {\color{blue} infected} conditioned on previous time step is a Bernoulli: +For each susceptible node $j$, the event that it becomes {\color{blue} infected} conditioned on previous time step is a Bernoulli variable: $$(j \in X_{t+1} | X_t) \sim {\cal B} \big(f(X_t \cdot \theta_j) \big)$$ \begin{itemize} \item $\theta_{i,j} := \log(1 - p_{i,j})$ @@ -159,7 +159,7 @@ $$(j \in X_{t+1} | X_t) \sim {\cal B} \big(f(X_t \cdot \theta_j) \big)$$ \begin{frame} \frametitle{Independent Cascade Model} -For each susceptible node $j$, the event that it becomes {\color{blue} infected} conditioned on previous time step is a Bernoulli: +For each susceptible node $j$, the event that it becomes {\color{blue} infected} conditioned on previous time step is a Bernoulli variable: $$(j \in X_{t+1} | X_t) \sim {\cal B} \big(f(X_t \cdot \theta_j) \big)$$ \begin{block}{Decomposability} @@ -197,7 +197,8 @@ $$(j \in X_{t+1} | X_t) \sim {\cal B} \big(f(X_t \cdot \theta_j) \big)$$ \begin{frame} \frametitle{Sparse Recovery} \begin{figure} -\includegraphics[scale=.6]{../images/sparse_recovery_illustration_copy.pdf} +\centering +\includegraphics[scale=.6]{../images/drawing.pdf} \caption{$\mathbb{P}(j \in X_{t+1}| X_t) = f(X_t\cdot \theta)$} \end{figure} \end{frame} @@ -221,7 +222,7 @@ $$(j \in X_{t+1} | X_t) \sim {\cal B} \big(f(X_t \cdot \theta_j) \big)$$ \end{align*} \end{block} -\begin{block}{MLE} +\begin{block}{Penalized log-likelihood} For each node $i$, $$\theta_i \in \arg \max \frac{1}{n_i}{\cal {L}}_i(\theta_i | X_1, X_2, \dots, X_{n_i}) - \lambda \|\theta_i\|_1$$ \end{block} @@ -242,7 +243,7 @@ For each node $i$, $$\theta_i \in \arg \max \frac{1}{n_i}{\cal {L}}_i(\theta_i | \begin{itemize} \item Want ${\cal H}$, the hessian of ${\cal L}$ with respect to $\theta$, to be well-conditioned. \item $ n < dim(\theta) \implies {\cal H}$ is degenerate. -\item {\bf Restricted Eigenvalue condition} = ``almost invertible'' on sparse vectors. +\item {\bf Restricted Eigenvalue condition} = invertible on ``almost sparse'' vectors. \end{itemize} \end{block} @@ -257,7 +258,7 @@ For each node $i$, $$\theta_i \in \arg \max \frac{1}{n_i}{\cal {L}}_i(\theta_i | For a set $S$, $${\cal C} := \{ \Delta : \|\Delta\|_2 = 1, \|\Delta_{\bar S}\|_1 \leq 3 \| \Delta_S\|_1 \}$$ ${\cal H}$ verifies the $(S, \gamma)$-RE condition if: -$$\forall \Delta \in {\cal C}, \Delta {\cal H} \Delta \geq \gamma$$ +$$\forall \Delta \in {\cal C}, \Delta^T {\cal H} \Delta \geq \gamma$$ \end{definition} \end{frame} %%%%%%%%%%%%%%%%%%%%%%%% @@ -310,7 +311,7 @@ By thresholding $\hat \theta_i$, if $n > C' s \log m$, we recover the support of \begin{block}{From Hessian to Gram Matrix} \begin{itemize} -\item If $\log f$ and $\log 1 -f$ are strictly log-concave with constant $c$, then if $(S, \gamma)$-RE holds for the gram matrix $\frac{1}{n}X X^T$ , then $(S, c \gamma)$-RE holds for ${\cal H}$ +\item If $f$ and $1 -f$ are strictly log-concave with constant $c$, then if $(S, \gamma)$-RE holds for the gram matrix $\frac{1}{n}X X^T$ , then $(S, c \gamma)$-RE holds for ${\cal H}$ \end{itemize} \end{block} @@ -362,11 +363,11 @@ requires ${\cal O}(s \log (n/s)/\log C)$ measurement. \begin{frame} \frametitle{Voter Model} \begin{itemize} -\pause + \item {\color{red} Red} and {\color{blue} Blue} nodes. At every step, each node $i$ chooses one of its neighbors $j$ with probability $p_{j,i}$ and adopts that color at $t+1$ -\pause + \item If {\color{blue} Blue} is `contagious' state: -\pause + \begin{equation} \nonumber \mathbb{P}(i \in X^{t+1}|X^t) = \sum_{j \in {\cal N}(i)\cap X^t} p_{ji} = X^t \cdot \theta_i |
