Technology
Hypothesis testing using pairwise distances and associated kernels (with Appendix)
Sejdinovic, Dino, Gretton, Arthur, Sriperumbudur, Bharath, Fukumizu, Kenji
We provide a unifying framework linking two classes of statistics used in two-sample and independence testing: on the one hand, the energy distances and distance covariances from the statistics literature; on the other, distances between embeddings of distributions to reproducing kernel Hilbert spaces (RKHS), as established in machine learning. The equivalence holds when energy distances are computed with semimetrics of negative type, in which case a kernel may be defined such that the RKHS distance between distributions corresponds exactly to the energy distance. We determine the class of probability distributions for which kernels induced by semimetrics are characteristic (that is, for which embeddings of the distributions to an RKHS are injective). Finally, we investigate the performance of this family of kernels in two-sample and independence tests: we show in particular that the energy distance most commonly employed in statistics is just one member of a parametric family of kernels, and that other choices from this family can yield more powerful tests.
- Asia > Middle East > Jordan (0.04)
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- Europe > United Kingdom > Scotland > City of Edinburgh > Edinburgh (0.04)
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- Information Technology > Artificial Intelligence > Machine Learning > Statistical Learning (0.67)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Uncertainty (0.46)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Scientific Discovery (0.41)
The View-Update Problem for Indefinite Databases
Caroprese, Luciano, Trubitsyna, Irina, Truszczynski, Miroslaw, Zumpano, Ester
This paper introduces and studies a declarative framework for updating views over indefinite databases. An indefinite database is a database with null values that are represented, following the standard database approach, by a single null constant. The paper formalizes views over such databases as indefinite deductive databases, and defines for them several classes of database repairs that realize view-update requests. Most notable is the class of constrained repairs. Constrained repairs change the database "minimally" and avoid making arbitrary commitments. They narrow down the space of alternative ways to fulfill the view-update request to those that are grounded, in a certain strong sense, in the database, the view and the view-update request.
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- North America > United States > Massachusetts > Middlesex County > Cambridge (0.04)
- Europe > Italy > Calabria (0.04)
Solving Limited Memory Influence Diagrams
Maua, D. D., de Campos, C. P., Zaffalon, M.
We present a new algorithm for exactly solving decision making problems represented as influence diagrams. We do not require the usual assumptions of no forgetting and regularity; this allows us to solve problems with simultaneous decisions and limited information. The algorithm is empirically shown to outperform a state-of-the-art algorithm on randomly generated problems of up to 150 variables and 10^64 solutions. We show that these problems are NP-hard even if the underlying graph structure of the problem has low treewidth and the variables take on a bounded number of states, and that they admit no provably good approximation if variables can take on an arbitrary number of states.
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- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Learning Graphical Models > Directed Networks > Bayesian Learning (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Uncertainty > Bayesian Inference (0.85)
Instructing a Reinforcement Learner
N., Pradyot Korupolu V. (Indian Institute of Technology Madras) | Sivamurugan, Manimaran S. (Indian Institute of Technology Madras) | Ravindran, Balaraman (IIT Madras)
In reinforcement learning (RL), rewards have been considered the most important feedback in understanding the environment. However, recently there have been interesting forays into other modes such as using sporadic supervisory inputs. This brings into the learning process richer information about the world of interest. In this paper, we model these supervisory inputs as specific types of instructions that provide information in the form of an expert's control decision and certain structural regularities in the state space. We further provide a mathematical formulation for the same and propose a framework to incorporate them into the learning process.
On the Complexity of Bribery and Manipulation in Tournaments with Uncertain Information
Mattei, Nicholas (University of Kentucky) | Goldsmith, Judy (University of Kentucky) | Klapper, Andrew (University of Kentucky)
We study the computational complexity of optimal bribery and manipulation schemes for sports tournaments with uncertain information: cup; challenge or caterpillar; and round robin. Our results carry over to the equivalent voting rules: sequential pair-wise elections, cup, and Copeland, when the set of candidates is exactly the set of voters. This restriction creates new difficulties for most existing algorithms. The complexity of bribery and manipulation are well studied, almost always assuming deterministic information about votes and results. We assume that for candidates i and j the probability that i beats j and the costs of lowering each probability by fixed increments are known to the manipulators. We provide complexity analyses for cup, challenge, and round robin competitions ranging from polynomial time to NP^PP. This shows that the introduction of uncertainty into the reasoning process drastically increases the complexity of bribery problems in some instances.
- Leisure & Entertainment > Sports (1.00)
- Government (1.00)
Social Influence Modeling for Utility Functions in Model Predictive Control
Dockins, Timothy Michael (The University of Texas at Arlington) | Huber, Manfred (The University of Texas at Arlington)
Social influence has no small effect on the preferences and behavior of agents in a social space. Contrary to rationality, we sometimes compromise our own needs for those of others. Thus, social influence has important implications in agent cognitive modeling for multi-objective decision-making problems. Namely, where these activities occur within a social context, the intentional preferences or utility of an agent may be subsumed, to a greater or lesser degree, by the influences of other agents. In this paper, a socially-aware model predictive controller is proposed using a social influence network theory and applied to a HVAC control problem. It transforms individual agent utility to socially-influenced utility reflecting interagent influences due to their existing relationships.
Special Track on Games and Entertainment
Hale, David Hunter (University of North Carolina Charlotte)
Digital games and entertainment are a modern area of enormous economic potential and can have a serious social impact. Digital entertainment has become a constant in our society. Exposure to it begins at a young age, sometimes even before children have started to walk. is exposure continues as they age and does not stop at adulthood, in fact the majority of game sales occur to those over the age of 18. is field represents a large and growing portion of the entertainment sector of the economy. Games are becoming the highest and most advanced form of escapism as they provide people of all ages the opportunity to see and do things that would not otherwise be possible. Effectively, the nonplayer controlled characters of twenty years ago are the same as the ones in current use, they just look better.
Mining Data from Project LISTEN’s Reading Tutor to Analyze Development of Children's Oral Reading Prosody
Sitaram, Sunayana (Carnegie Mellon University) | Mostow, Jack (Carnegie Mellon University)
Reading tutors can provide an unprecedented opportunity to collect and analyze large amounts of data for understanding how students learn. We trained models of oral reading prosody (pitch, intensity, and duration) on a corpus of narrations of 4558 sentences by 11 fluent adults. We used these models to evaluate the oral reading prosody of 85,209 sentences read by 55 children (mostly) 7-10 years old who used Project LISTEN's Reading Tutor during the 2005-2006 school year. We mined the resulting data to pinpoint the specific common syntactic and lexical features of text that children scored best and worst on. These features predict their fluency and comprehension test scores and gains better than previous models. Focusing on these features may help human or automated tutors improve children’s fluency and comprehension more effectively.
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Case-Based Learning by Observation in Robotics Using a Dynamic Case Representation
Floyd, Michael William (Carleton University) | Bicakci, Mehmet Vefa (Carleton University) | Esfandiari, Babak (Carleton University)
Robots are becoming increasingly common in home, industrial and medical environments. Their end users may know what they want the robots to do but lack the required technical skills to program them. We present a case-based reasoning approach for training a control module that controls a multi-purpose robotic platform. The control module learns by observing an expert performing a task and does not require any human intervention to program or modify the control module. To avoid requiring the control module to be modified when the robot it controls is repurposed, smart sensors and effectors register with the control module allowing it to dynamically modify the case structure it uses and how those cases are compared. This allows the hardware configuration to be modified, or completely changed, without having to change the control module. We present a case study demonstrating how a robot can be trained using learning by observation and later repurposed with new sensors and then retrained.
Iterative-Expansion A*
Potts, Colin M. (Lawrence University) | Krebsbach, Kurt D. (Lawrence University)
In this paper we describe an improvement to the popular IDA* search algorithm that emphasizes a different space-for-time trade-off than previously suggested. In particular, our algorithm, called Iterative-Expansion A* (IEA*), focuses on reducing redundant node expansions within individual depth-first search DFS iterations of IDA* by employing a relatively small amount of available memory--bounded by the error in the heuristic--to store selected nodes. The additional memory required is exponential not in the solution depth, but only in the difference between the solution depth and the estimated solution depth. A constant-time hash set lookup can then be used to prune entire subtrees as DFS proceeds. Overall, we show 2- to 26-fold time speedups vs. an optimized version of IDA* across several domains, and compare IEA* with several other competing approaches. We also sketch proofs of optimality and completeness for IEA*, and note that IEA* is particularly efficient for solving implicitly-defined general graph search problems.