Questions tagged [hidden-markov-models]
This tag is for questions relating to "Hidden Markov model", a statistical Markov model in which the system being modeled is assumed to be a Markov process with unobservable (i.e. hidden) states.
94 questions
1 vote
1 answer
92 views
Hidden Markov model (HMM) for multiple time series
I have a question regarding training HMM and then applying it to new data: Is it possible to train a HMM with several time series as inputs? My point here is that it'd be convenient to have a ...
0 votes
0 answers
29 views
Jurafsky Speech & language processing Chapter 3 "end-symbol to make the bigram grammar a true probability distribution"
In Chapeter 3 of Speech & language processing, Jurafsky says "We need the end-symbol to make the bigram grammar a true probability distribution. Without an endsymbol,instead of the sentence ...
4 votes
0 answers
126 views
Property of a Markov renewal process
Definition of a a Markov renewal process: Let the states of a process be denoted by the set $E= \{0,1,2, \dots\}$ and let the transitions of the process occur at epochs $t_0 =0,t_1,t_2, \dots$. Let $...
0 votes
0 answers
57 views
Proving Termination Properties of a Markov Chain with Non-Constant Transition Probabilities
I am working through a problem in my textbook regarding Markov chains and hidden Markov models (HMMs). The problem is as follows: Prove that $P(\pi)$ is equal to the product of the transmission ...
1 vote
1 answer
149 views
Hidden Markov Model Likelihood when Marginal Density Isn't avaliable?
The question might be trivial or non-sensical but help me understand, please. My understanding so far: The likelihood is given by $$ L_T=\boldsymbol{\delta \text{P}}(x_1)\boldsymbol{\Gamma \text{P}}(...
0 votes
1 answer
133 views
Hidden Markov Model with Multiple Agents
Consider this problem where a machine can be in either of two states (bad or good) and depending on the state with some probabilities (p_1 and p_2) it may produce good products (with probabilities 1-...
0 votes
1 answer
102 views
Hidden Markov with both discrete and continuous states
Is there a formalism for a Hidden Markov model that is : time-discrete with both discrete and continuous states with continuous (gaussian linear) observation (of the continuous space) ? For specifics,...
1 vote
1 answer
541 views
Discrete Hidden Markov Model with continuous observation
Say I have a HMM system that can be in any of $n$ discrete possible states - say they are numbered $1$ to $n$ and can even actually be these integers. I know the transition matrix between different ...
0 votes
0 answers
110 views
Hidden Markov Model of a stationary Markov chain is a stationary process.
Let $X=(X_i)_{i \ge 1}$ be an irreducible Markov chain started in its stationary distribution, and $Y=(Y_i)_{i \ge 1}$ be such that $Y_i=\phi(X_i)$ for an arbitrary function $\phi$. Note that $X$ is a ...
1 vote
0 answers
56 views
EM algorithm for Markov switching models.
Consider the model $y_t = F_{S_t} x_t + \varepsilon_{S_t}$ and $x_t = A_{S_t} x_{t-1} + \nu_{S_t}$, where $\varepsilon_{S_t}, \nu_{S_t} \sim N(0, R_{S_t})$ and $N(0, Q_{S_t})$ and $S_t$ is Markov ...
0 votes
1 answer
110 views
Likelihood computation for hidden markov models.
If we have a $2$-state model (i.e. the simplest non-trivial example) in a hidden markov model, and some generated observation-data $\mathcal{O}$ from the algorithm for generating observations. Is it ...
2 votes
0 answers
63 views
When do mixtures of ergodic Markov kernels remain ergodic?
Given two Markov kernels on the same space $\mathfrak X$ and relative to the same dominating measure, $K_0(\cdot,\cdot)$ and $K_1(\cdot,\cdot)$, both ergodic with respective stationary distribution ...
-1 votes
1 answer
68 views
Hidden Markov Model - Observations [closed]
I'm struggling to understand the statistic relation referring the observations of an HMM. That's clear for me: Output Independence My problem is how this equation can be derived: probability of an ...
0 votes
1 answer
75 views
First-passage time distribution in Laplace space?
I'm struggling to understand the reasoning between moving between two steps in a reaction scheme for a paper I am reading. For this (from the description), the probabilities over different paths are ...
1 vote
0 answers
90 views
Derivation of Viterbi Algorithm
I am trying to understand the derivation of the Viterbi algorithm for hidden Markov models. I understand that the motivation is to find the maximum probability path estimate, i.e., \begin{equation} ...