Genre
A Probabilistic Framework for Learning Kinematic Models of Articulated Objects
Sturm, J., Stachniss, C., Burgard, W.
Robots operating in domestic environments generally need to interact with articulated objects, such as doors, cabinets, dishwashers or fridges. In this work, we present a novel, probabilistic framework for modeling articulated objects as kinematic graphs. Vertices in this graph correspond to object parts, while edges between them model their kinematic relationship. In particular, we present a set of parametric and non-parametric edge models and how they can robustly be estimated from noisy pose observations. We furthermore describe how to estimate the kinematic structure and how to use the learned kinematic models for pose prediction and for robotic manipulation tasks. We finally present how the learned models can be generalized to new and previously unseen objects. In various experiments using real robots with different camera systems as well as in simulation, we show that our approach is valid, accurate and efficient. Further, we demonstrate that our approach has a broad set of applications, in particular for the emerging fields of mobile manipulation and service robotics.
Emotional Analysis of Blogs and Forums Data
Weroński, Paweł, Sienkiewicz, Julian, Paltoglou, Georgios, Buckley, Kevan, Thelwall, Mike, Hołyst, Janusz A.
The Blogs dataset is a subset of Recent years have resulted in several well motivated the Blogs06 [16] collection of blog posts from 06/12/2005 and carefully described studies coping with the problem to 21/02/2006. Only posts attracting more than 100 of opinion formation and its spreading [1]. This kind of comments were extracted, as these apparently initialised research usually aimed at qualitative descriptions of some non-trivial discussions. Both datasets have similar structures.
Dimension Reduction Using Rule Ensemble Machine Learning Methods: A Numerical Study of Three Ensemble Methods
DeMasi, Orianna, Meza, Juan, Bailey, David H.
Ensemble methods for supervised machine learning have become popular due to their ability to accurately predict class labels with groups of simple, lightweight "base learners." While ensembles offer computationally efficient models that have good predictive capability they tend to be large and offer little insight into the patterns or structure in a dataset. We consider an ensemble technique that returns a model of ranked rules. The model accurately predicts class labels and has the advantage of indicating which parameter constraints are most useful for predicting those labels. An example of the rule ensemble method successfully ranking rules and selecting attributes is given with a dataset containing images of potential supernovas where the number of necessary features is reduced from 39 to 21. We also compare the rule ensemble method on a set of multi-class problems with boosting and bagging, which are two well known ensemble techniques that use decision trees as base learners, but do not have a rule ranking scheme.
Sparse Partitioning: Nonlinear regression with binary or tertiary predictors, with application to association studies
This paper presents Sparse Partitioning, a Bayesian method for identifying predictors that either individually or in combination with others affect a response variable. The method is designed for regression problems involving binary or tertiary predictors and allows the number of predictors to exceed the size of the sample, two properties which make it well suited for association studies. Sparse Partitioning differs from other regression methods by placing no restrictions on how the predictors may influence the response. To compensate for this generality, Sparse Partitioning implements a novel way of exploring the model space. It searches for high posterior probability partitions of the predictor set, where each partition defines groups of predictors that jointly influence the response. The result is a robust method that requires no prior knowledge of the true predictor--response relationship. Testing on simulated data suggests Sparse Partitioning will typically match the performance of an existing method on a data set which obeys the existing method's model assumptions. When these assumptions are violated, Sparse Partitioning will generally offer superior performance.
Confidentiality-Preserving Data Publishing for Credulous Users by Extended Abduction
Inoue, Katsumi, Sakama, Chiaki, Wiese, Lena
Publishing private data on external servers incurs the problem of how to avoid unwanted disclosure of confidential data. We study a problem of confidentiality in extended disjunctive logic programs and show how it can be solved by extended abduction. In particular, we analyze how credulous non-monotonic reasoning affects confidentiality.
A Constraint Logic Programming Approach for Computing Ordinal Conditional Functions
Beierle, Christoph, Kern-Isberner, Gabriele, Södler, Karl
In order to give appropriate semantics to qualitative conditionals of the form "if A then normally B", ordinal conditional functions (OCFs) ranking the possible worlds according to their degree of plausibility can be used. An OCF accepting all conditionals of a knowledge base R can be characterized as the solution of a constraint satisfaction problem. We present a high-level, declarative approach using constraint logic programming techniques for solving this constraint satisfaction problem. In particular, the approach developed here supports the generation of all minimal solutions; these minimal solutions are of special interest as they provide a basis for model-based inference from R.
Structure Selection from Streaming Relational Data
Mihalkova, Lilyana, Moustafa, Walaa Eldin
Statistical relational learning techniques have been successfully applied in a wide range of relational domains. In most of these applications, the human designers capitalized on their background knowledge by following a trial-and-error trajectory, where relational features are manually defined by a human engineer, parameters are learned for those features on the training data, the resulting model is validated, and the cycle repeats as the engineer adjusts the set of features. This paper seeks to streamline application development in large relational domains by introducing a light-weight approach that efficiently evaluates relational features on pieces of the relational graph that are streamed to it one at a time. We evaluate our approach on two social media tasks and demonstrate that it leads to more accurate models that are learned faster.
A prototype of a knowledge-based programming environment
De Pooter, Stef, Wittocx, Johan, Denecker, Marc
In this paper we present a proposal for a knowledge-based programming environment. In such an environment, declarative background knowledge, procedures, and concrete data are represented in suitable languages and combined in a flexible manner. This leads to a highly declarative programming style. We illustrate our approach on an example and report about our prototype implementation.
Parsing Combinatory Categorial Grammar with Answer Set Programming: Preliminary Report
Lierler, Yuliya, Schüller, Peter
Combinatory categorial grammar (CCG) is a grammar formalism used for natural language parsing. CCG assigns structured lexical categories to words and uses a small set of combinatory rules to combine these categories to parse a sentence. In this work we propose and implement a new approach to CCG parsing that relies on a prominent knowledge representation formalism, answer set programming (ASP) - a declarative programming paradigm. We formulate the task of CCG parsing as a planning problem and use an ASP computational tool to compute solutions that correspond to valid parses. Compared to other approaches, there is no need to implement a specific parsing algorithm using such a declarative method. Our approach aims at producing all semantically distinct parse trees for a given sentence. From this goal, normalization and efficiency issues arise, and we deal with them by combining and extending existing strategies. We have implemented a CCG parsing tool kit - AspCcgTk - that uses ASP as its main computational means. The C&C supertagger can be used as a preprocessor within AspCcgTk, which allows us to achieve wide-coverage natural language parsing.
Selectivity in Probabilistic Causality: Drawing Arrows from Inputs to Stochastic Outputs
Dzhafarov, Ehtibar N., Kujala, Janne V.
The problem has applications ranging from modeling pairwise comparisons to reconstructing mental processing architectures to conjoint testing. A necessary and sufficient condition for a given pattern of selective influences is provided by the Joint Distribution Criterion, according to which the problem of "what influences what" is equivalent to that of the existence of a joint distribution for a certain set of random variables. For inputs and outputs with finite sets of values this criterion translates into a test of consistency of a certain system of linear equations and inequalities (Linear Feasibility Test) which can be performed by means of linear programming. The Joint Distribution Criterion also leads to a metatheoretical principle for generating a broad class of necessary conditions (tests) for diagrams of selective influences. Among them is the class of distance-type tests based on the observation that certain functionals on jointly distributed random variables satisfy triangle inequality. A B C The Greek letters in this diagram represent inputs, or external factors, e.g., parameters of stimuli whose values can be chosen at will, or randomly vary but can be observed. The capital Roman letters stand for random outputs characterizing reactions of the system (an observer, a group of observers, a technical device, etc.). The arrows show which factor influences which random output. The factors are treated as deterministic entities: even if α,β,γ,δ in reality vary randomly (e.g., being randomly generated by a computer program, or being concomitant parameters of observations, such as age of respondents), for the purposes of analyzing selective influences the random outputs A, B,C are always viewed as conditioned upon various combinations of specific values of α,β,γ,δ. The first question to ask is: what is the meaning of the above diagram if the random outputs A,B,C in it are not necessarily stochastically independent?