Uncertainty
Lifted Probabilistic Inference by First-Order Knowledge Compilation
Broeck, Guy Van den (Katholieke Universiteit Leuven) | Taghipour, Nima (Katholieke Universiteit Leuven) | Meert, Wannes (Katholieke Universiteit Leuven) | Davis, Jesse (Katholieke Universiteit Leuven) | Raedt, Luc De (Katholieke Universiteit Leuven)
Probabilistic logical languages provide powerful formalisms forknowledge representation and learning. Yet performing inference inthese languages is extremely costly, especially if it is done at thepropositional level. Lifted inference algorithms, which avoid repeatedcomputation by treating indistinguishable groups of objects as one, helpmitigate this cost. Seeking inspiration from logical inference, wherelifted inference (e.g., resolution) is commonly performed, we developa model theoretic approach to probabilistic lifted inference. Our algorithmcompiles a first-order probabilistic theory into a first-orderdeterministic decomposable negation normal form (d-DNNF) circuit.Compilation offers the advantage that inference is polynomial in thesize of the circuit. Furthermore, by borrowing techniques from theknowledge compilation literature our algorithm effectively exploitsthe logical structure (e.g., context-specific independencies) withinthe first-order model, which allows more computation to be done at the lifted level.An empirical comparison demonstrates the utility of the proposed approach.
Unsupervised Modeling of Dialog Acts in Asynchronous Conversations
Joty, Shafiq Rayhan (University of British Columbia) | Carenini, Giuseppe (University of British Columbia) | Lin, Chin-Yew (Microsoft Research Asia)
We present unsupervised approaches to the problem of modeling dialog acts in asynchronous conversations; i.e., conversations where participants collaborate with each other at different times. In particular, we investigate a graph-theoretic deterministic framework and two probabilistic conversation models (i.e., HMM and HMM+Mix) for modeling dialog acts in emails and forums. We train and test our conversation models on (a) temporal order and (b) graph-structural order of the datasets. Empirical evaluation suggests (i) the graph-theoretic framework that relies on lexical and structural similarity metrics is not the right model for this task, (ii) conversation models perform better on the graph-structural order than the temporal order of the datasets and (iii) HMM+Mix is a better conversation model than the simple HMM model.
A Logic for Causal Inference in Time Series with Discrete and Continuous Variables
Kleinberg, Samantha (Columbia University)
Many applications of causal inference, such as finding the relationship between stock prices and news reports, involve both discrete and continuous variables observed over time. Inference with these complex sets of temporal data, though, has remained difficult and required a number of simplifications. We show that recent approaches for inferring temporal relationships (represented as logical formulas) can be adapted for inference with continuous valued effects. Building on advances in logic, PCTLc (an extension of PCTL with numerical constraints) is introduced here to allow representation and inference of relationships with a mixture of discrete and continuous components. Then, finding significant relationships in the continuous case can be done using the conditional expectation of an effect, rather than its conditional probability. We evaluate this approach on both synthetically generated and actual financial market data, demonstrating that it can allow us to answer different questions than the discrete approach can.
Unsupervised Lexicon Acquisition for HPSG-Based Relation Extraction
Rozenfeld, Benjamin (Digital Trowel) | Feldman, Ronen (Hebrew University of Jerusalem)
The paper describes a method of relation extraction, which is based on parsing the input text using a combination of a generic HPSG-based grammar and a highly focused domain- and relation-specific lexicon. We also show a method of unsupervised acquisition of such a lexicon from a large unlabeled corpus. Together, the methods introduce a novel approach to the “Open IE” task, which is superior in accuracy and in quality of relation identification to the existing approaches.
Unsupervised Lexicon Acquisition for HPSG-Based Relation Extraction
Rozenfeld, Benjamin (Digital Trowel) | Feldman, Ronen (Hebrew University of Jerusalem)
The paper describes a method of relation extraction, which is based on parsing the input text using a combination of a generic HPSG-based grammar and a highly focused domain- and relation-specific lexicon. We also show a method of unsupervised acquisition of such a lexicon from a large unlabeled corpus. Together, the methods introduce a novel approach to the “Open IE” task, which is superior in accuracy and in quality of relation identification to the existing approaches.
Unsupervised Lexicon Acquisition for HPSG-Based Relation Extraction
Rozenfeld, Benjamin (Digital Trowel) | Feldman, Ronen (Hebrew University of Jerusalem)
The paper describes a method of relation extraction, which is based on parsing the input text using a combination of a generic HPSG-based grammar and a highly focused domain- and relation-specific lexicon. We also show a method of unsupervised acquisition of such a lexicon from a large unlabeled corpus. Together, the methods introduce a novel approach to the “Open IE” task, which is superior in accuracy and in quality of relation identification to the existing approaches.
Unsupervised Lexicon Acquisition for HPSG-Based Relation Extraction
Rozenfeld, Benjamin (Digital Trowel) | Feldman, Ronen (Hebrew University of Jerusalem)
The paper describes a method of relation extraction, which is based on parsing the input text using a combination of a generic HPSG-based grammar and a highly focused domain- and relation-specific lexicon. We also show a method of unsupervised acquisition of such a lexicon from a large unlabeled corpus. Together, the methods introduce a novel approach to the “Open IE” task, which is superior in accuracy and in quality of relation identification to the existing approaches.
Unsupervised Lexicon Acquisition for HPSG-Based Relation Extraction
Rozenfeld, Benjamin (Digital Trowel) | Feldman, Ronen (Hebrew University of Jerusalem)
The paper describes a method of relation extraction, which is based on parsing the input text using a combination of a generic HPSG-based grammar and a highly focused domain- and relation-specific lexicon. We also show a method of unsupervised acquisition of such a lexicon from a large unlabeled corpus. Together, the methods introduce a novel approach to the “Open IE” task, which is superior in accuracy and in quality of relation identification to the existing approaches.
Unsupervised Lexicon Acquisition for HPSG-Based Relation Extraction
Rozenfeld, Benjamin (Digital Trowel) | Feldman, Ronen (Hebrew University of Jerusalem)
The paper describes a method of relation extraction, which is based on parsing the input text using a combination of a generic HPSG-based grammar and a highly focused domain- and relation-specific lexicon. We also show a method of unsupervised acquisition of such a lexicon from a large unlabeled corpus. Together, the methods introduce a novel approach to the “Open IE” task, which is superior in accuracy and in quality of relation identification to the existing approaches.
Unsupervised Lexicon Acquisition for HPSG-Based Relation Extraction
Rozenfeld, Benjamin (Digital Trowel) | Feldman, Ronen (Hebrew University of Jerusalem)
The paper describes a method of relation extraction, which is based on parsing the input text using a combination of a generic HPSG-based grammar and a highly focused domain- and relation-specific lexicon. We also show a method of unsupervised acquisition of such a lexicon from a large unlabeled corpus. Together, the methods introduce a novel approach to the “Open IE” task, which is superior in accuracy and in quality of relation identification to the existing approaches.