Uncertainty
Bayesian Abductive Logic Programs
Raghavan, Sindhu V. (The University of Texas at Austin) | Mooney, Raymond J. (The University of Texas at Austin)
In this paper, we introduce Bayesian Abductive Logic Programs (BALPs), a new formalism that integrates Bayesian Logic Programs (BLPs) and Abductive Logic Programming (ALP) for abductive reasoning. Like BLPs, BALPs also combine first-order logic and Bayesian networks. However, unlike BLPs that use logical deduction to construct Bayes nets, BALPs employ logical abduction. As a result, BALPs are more suited for solving problems like plan/activity recognition and diagnosis that require abductive reasoning. First, we present the necessary enhancements to BLPs in order to support logical abduction. Next, we apply BALPs to the task of plan recognition and demonstrate its efficacy on two data sets. We also compare the performance of BALPs with several existing approaches for abduction.
Automatic Inference in BLOG
Arora, Nimar S. (University of California, Berkeley) | Russell, Stuart (University of California, Berkeley) | Sudderth, Erik (Brown University)
BLOG is a powerful language to express models with an unknown number of objects and identity uncertainty. Current inference engines for BLOG are either too slow or require users to write a model-specific proposal distribution. We describe here, ongoing work to design a new, fast, generic inference engine for BLOG called blogc. The new implementation uses Gibbs sampling for finite-valued variables and performs an analysis of the model to generate customized sampling code in C. We describe our algorithms and methods in the context of various commonly used models and demonstrate significant performance improvement.
Lifted Inference for Relational Continuous Models
Choi, Jaesik (University of Illinois at Urbana-Champaign) | Hill, David J. (Rutgers, The State University of New Jersey) | Amir, Eyal (University of Illinois at Urbana-Champaign)
Relational Continuous Models (RCMs) represent joint probability densities over attributes of objects, when the attributes have continuous domains. With relational representation, they can model joint probability distributions over large numbers of variables compactly in a natural way. This paper presents the first exact inference algorithm for RCMs at a lifted level, so that it scales up to large models of real world applications. The algorithm applies to relational pairwise models which are (relational) products of potentials of arity 2. Our algorithm is unique in two ways. First, it is an efficient lifted inference algorithm. When Gaussian potentials are used, it takes only linear time while existing methods take cubic time. Second, it is the first exact inference algorithm which handles RCMs in a lifted way. The algorithm is illustrated over an example from Econometrics. Experimental results show that our algorithm outperforms both a ground-level inference algorithm and an algorithm built with previously-known lifted methods
Efficient Lifting for Online Probabilistic Inference
Nath, Aniruddh (University of Washington) | Domingos, Pedro (University of Washington)
Lifting can greatly reduce the cost of inference on first-order probabilistic graphical models, but constructing the lifted network can itself be quite costly. In online applications (e.g., video segmentation) repeatedly constructing the lifted network for each new inference can be extremely wasteful, because the evidence typically changes little from one inference to the next. The same is true in many other problems that require repeated inference, like utility maximization, MAP inference, interactive inference, parameter and structure learning, etc. In this paper, we propose an efficient algorithm for updating the structure of an existing lifted network with incremental changes to the evidence. This allows us to construct the lifted network once for the initial inference problem, and amortize the cost over the subsequent problems. Experiments on video segmentation and viral marketing problems show that the algorithm greatly reduces the cost of inference without affecting the quality of the solutions.
Sampling and Updating Higher Order Beliefs in Decision-Theoretic Bargaining Under Uncertainty
Varkey, Paul (University of Illinois at Chicago) | Gmytrasiewicz, Piotr (University of Illinois at Chicago)
In this paper we study the sequential strategic interactive setting of two-person, two-stage, seller-offers bargaining under uncertainty. We model the epistemology of the problem in a finite interactive decision-theoretic framework and solve it for three types of agents of successively increasing (epistemological) sophistication (or, capacity to represent and reason with higher orders of beliefs). In particular, we remove common knowledge assumptions about the agents' epistemology which, if made, would be sufficient to imply the existence of a, possibly unique, game-theoretic equilibrium solution. In this context, we present a characterization of a monotonic relationship between an agent's optimal behavior and its beliefs under a particular moment-based ordering. Further, based on this characterization, we present the \emph{spread-accumulate} sampling technique -- a method of sampling an agent's higher order belief by generating ``evenly dispersed" beliefs for which we (pre)compute offline solutions. Then, we present a method for approximating higher order prior belief update to arbitrary precision by identifying a (previously solved) belief ``closest" to the true belief. In addition, these methods directly suggest a mechanism for achieving a balance between efficiency and the quality of the approximation -- either by generating a large number of offline solutions or by allowing the agent to search online for a ``closer" belief in the vicinity of best current solution.
Machine Reading: A "Killer App" for Statistical Relational AI
Poon, Hoifung (University of Washington) | Domingos, Pedro (University of Washington)
Machine reading aims to automatically extract knowledge from text. It is a long-standing goal of AI and holds the promise of revolutionizing Web search and other fields. In this paper, we analyze the core challenges of machine reading and show that statistical relational AI is particularly well suited to address these challenges. We then propose a unifying approach to machine reading in which statistical relational AI plays a central role. Finally, we demonstrate the promise of this approach by presenting OntoUSP, an end-to-end machine reading system that builds on recent advances in statistical relational AI and greatly outperforms state-of-the-art systems in a task of extracting knowledge from biomedical abstracts and answering questions.
Possibilistic Behavior Recognition in Smart Homes for Cognitive Assistance
Roy, Patrice C. (Domus Lab, Universite de Sherbrooke) | Giroux, Sylvain (Domus Lab, Université) | Bouchard, Bruno (de Sherbrooke) | Bouzouane, Abdenour (LIARA Lab, Université) | Phua, Clifton (du Québec à) | Tolstikov, Andrei (Chicoutimi) | Biswas, Jit (LIARA Lab, Université)
Providing cognitive assistance in smart homes is a field of research that receives a lot of attention lately. In order to give adequate assistance at the opportune moment, we need to recognize the observed behavior when the patient carries out some activities in a smart home. To address this challenging issue, we present a formal activity recognition framework based on possibility theory. We present initial results from an implementation of this possibilistic recognition approach in a smart home laboratory.
Speculations on Leveraging Graphical Models for Architectural Integration of Visual Representation and Reasoning
Rosenbloom, Paul (University of Southern California)
The starting point is an ongoing effort to structure underlying intelligent behavior, whether intended reconstruct cognitive architectures from the ground up via as models of human intelligence and/or implementations of graphical models (Koller and Friedman 2009), with the artificial intelligence (Langley, Laird and Rogers 2009). A aim of understanding existing architectures better, basic cognitive architecture may comprise memories, exploring the overall space of architectures, and decision algorithms, learning mechanisms, and some developing new and improved architectures (Rosenbloom means of interacting with external environments.
Stochastic Planning and Lifted Inference
Khardon, Roni (Tufts University)
The paper argues that (1) stochastic planning should be used as a core problem domain for relational probabilistic models providing problems of interest that are challenging for current approaches and significant scope for extending their capabilities, (2) that symbolic dynamic programming solving such problems can be seen as a prime example of lifted inference in relational probabilistic problems, (3) that first order decision diagrams provide a useful tool to drive such lifted computations, and (4) that the resulting lifted inference is qualitatively different from what other approaches are providing. As a result, this relationship can be studied to the benefit of developing foundations for relational probabilistic models and to the benefit of stochastic planning.
Preface
Kersting, Kristian (Fraunhofer IAIS and University of Bonn) | Russell, Stuart (University of California, Berkeley) | Kaelbling, Leslie Pack (Massachusetts Institute of Technology) | Halevy, Alon (University of Wisconsin Madison) | Natarajan, Sriraam (University of Texas at Austin) | Mihalkova, Lilyana
Much has been achieved in the field of AI, yet much remains Gibbs sampling code in C/C . Chechetka et al. investigate relational learning for collective classification of entities to be done if we are to reach the goals we all imagine. in images. Choi et al. present a lifted inference One of the key challenges with moving ahead is closing approach for relational continuous models. Logical AI has Gogate and Domingos shows how to exploit logical structure mainly focused on complex representations, and statistical in lifted probabilistic inference. Hadiji et al. discuss AI on uncertainty.