Learning Graphical Models
Reviews: Policy-Conditioned Uncertainty Sets for Robust Markov Decision Processes
The authors consider distributionally robust finite MDPs over a finite horizon. The transition probabilities conditionally to a state-action pair should remain at L1-bounded distance from a base measure, which is feasible as being generated using a given reference policy. This is a nice idea. A few comments are mentioned next. Related to that question, why the requirement of staying "close" to this policy would be beneficial.
Reviews: Bayesian Model Selection Approach to Boundary Detection with Non-Local Priors
Update: I downgrade my review to 5. The main concern is 1) Some more extensive simulations will make the results more convincing, as the numerical experiment is the only way to assess the performance of the proposed priors. It might take a major revision to reflect such comprehensive comparisons. With that being said, I believe the paper does contain interesting results that are novel and useful to the community. In particular, the theoretical results seem sound, and the paper is fairly readable. But I think there is also room for improvement.
Reviews: Multi-domain Causal Structure Learning in Linear Systems
The authors leverage on data recorded in multiple domains with changing parameters of a linear Gaussian models to learn causal direction and relations beyond Markov equivalence class. The paper is clearly written and includes good synthetic data simulations. The result is theoretically interesting. The method seems to need a lot of samples and domains that may not be available in real cases. The authors present different options to improve the methods in this respect.
Reviews: Inverse Filtering for Hidden Markov Models
The paper addresses recovery of the observation sequence given known posterior state estimates, but unknown observations and/or sensor model and also in an extension, noise-corrupted measurements. There is a nice progression of the problem through IP, LP, and MILP followed by a more careful analytical derivation of the answers in the noise-free case, and a seemingly approximate though empirically effective approach (cf. Honestly, most of the motivations seem to be unrealistic, especially the cyber-physical security setting where one does not observe posteriors, but simply an action based on a presumed argmax w.r.t. The EEG application (while somewhat narrow) seems to be the best motivation, however, the sole example is to compare resconstructed observations to a redundant method of sensing -- is this really a compelling application? Is it actually used in practice?
Reviews: Online Structure Learning for Feed-Forward and Recurrent Sum-Product Networks
This paper proposed an online learning algorithm for static and dynamic sum-product networks (SPNs), a type of probabilistic model with tractable inference. The authors essentially combine local structure search in SPNs with a hard variant of expectation-maximization [1]. The algorithm maintains empirical covariance estimates of product nodes and leverages statistical dependence tests to decide when to replace a product (factorized distribution) with either a new leaf or a mixture (sum node). The algorithm further includes a pruning mechanism in order to trim over-grown structures. The proposed method is called online Structure Learning with Running Average Update (oSLRAU).
Reviews: Learning Others' Intentional Models in Multi-Agent Settings Using Interactive POMDPs
The paper describes a sampling method for learning agent behaviors in interactive POMDPs (I-POMDPs). In general, I-POMDPs are a multi-agent POMDP model which, in addition to a belief about the environment state, the belief space includes nested recursive beliefs about the other agents' models. I-POMDP solutions, including the one proposed in the paper, largely approximate using a finite depth with either intentional models of others (e.g., their nested beliefs, state transitions, optimality criterion, etc.) or subintentional models of others (e.g., essentially "summaries of behavior" such as fictitious play). The proposed approach uses samples of the other agent at a particular depth to compute its values and policy. Related work on an interactive particle filter assumed the full frame was known (b, S, A, Omega, T, R, OC).
Reviews: Bayesian Adversarial Learning
This paper proposes a Bayesian model for adversarial learning problem. Empirical studies on Fashion-MINST and traffic sign recognition show that the proposed methods is slightly better than other adversarial learning baselines. Below I list my concerns about the paper: For modeling, 1. This paper ignore a highly relevant work'Bayesian GAN' [1]. The non-cooperative game between'data generator' and'learner' established in this paper is almost the same as the vanilla GAN.
Reviews: Monte-Carlo Tree Search for Constrained POMDPs
This paper addresses a potentially important problem by giving an algorithm that can solve large constrained POMDPs with online methods. A constrained POMDP, which augments a traditional POMDP with multi-attribute cost constraints, is an important extension that can help model a wider range of real-world phenomena than a POMDP can. Having such an algorithm for solving large CPOMDPs is a very valuable contribution. The authors provide, in this paper, a derivation of an unconstrained objective to be solved (resulting from taking the dual of the CPOMDP's linear program), backed by theoretical justification, and an adaptation of the online search algorithm, POMCP, that incorporates cost constraints by approximately optimizing the objective. The paper is extremely well-written, free of typos, and clear in its presentation.
Reviews: From Stochastic Planning to Marginal MAP
Main ideas The paper develops the relation between solving an MDP and performing inference in a Bayesian network. The direction, however, is novel as far as I can tell: using MDP algorithms to solve an inference problem. The first part shows that an existing MDP algorithm (ARollout) is in fact performing a BP iteration over the DBN that represents the MDP. In the second part, a different MDP algorithm (SOGBOFA) is used to solve a particular inference problem of choosing a subset of values with the maximal marginals (MMAP). The resulting SOGBOFA-based solver often loses to the state-of-the-art, but for harder cases it can outperform the state of the art.
Reviews: Deep Poisson gamma dynamical systems
This paper presents Deep Poisson-Gamma Dynamical System (DPGDS) for modeling temporal multivariate count data. It is based on previously developed Gamma-Belief networks, extended to the dynamical scenarios by adding transitions of latent units in consecutive times. The paper is well written, and connections to previous papers are explained clearly. While the temporal structure is based on transition of latent units in a Markov manner, the authors' claim about better capturing long-range temporal changes should be justified more clearly. In line 30, "separated" should be replaced by "separately".