Logic & Formal Reasoning
Specifying and Computing Causes for Query Answers in Databases via Database Repairs and Repair Programs
A correspondence between database tuples as causes for query answers in databases and tuple-based repairs of inconsistent databases with respect to denial constraints has already been established. In this work, answer-set programs that specify repairs of databases are used as a basis for solving computational and reasoning problems about causes. Here, causes are also introduced at the attribute level by appealing to a both null-based and attribute-based repair semantics. The corresponding repair programs are presented, and they are used as a basis for computation and reasoning about attribute-level causes. They are extended to deal with the case of causality under integrity constraints. Several examples with the DLV system are shown.
Homunculus' Brain and Categorical Logic
The interaction between syntax (formal language) and its semantics (meanings of language) is well studied in categorical logic. Results of this study are employed to understand how the brain could create meanings. To emphasize the toy character of the proposed model, we prefer to speak on homunculus' brain rather than just on the brain. Homunculus' brain consists of neurons, each of which is modeled by a category, and axons between neurons, which are modeled by functors between the corresponding neuron-categories. Each neuron (category) has its own program enabling its working, i.e. a "theory" of this neuron. In analogy with what is known from categorical logic, we postulate the existence of the pair of adjoint functors, called Lang and Syn, from a category, now called BRAIN, of categories, to a category, now called MIND, of theories. Our homunculus is a kind of "mathematical robot", the neuronal architecture of which is not important. Its only aim is to provide us with the opportunity to study how such a simple brain-like structure could "create meanings" out of its purely syntactic program. The pair of adjoint functors Lang and Syn models mutual dependencies between the syntactical structure of a given theory of MIND and the internal logic of its semantics given by a category of BRAIN. In this way, a formal language (syntax) and its meanings (semantics) are interwoven with each other in a manner corresponding to the adjointness of the functors Lang and Syn. Categories BRAIN and MIND interact with each other with their entire structures and, at the same time, these very structures are shaped by this interaction.
On Constrained Open-World Probabilistic Databases
Friedman, Tal, Broeck, Guy Van den
Increasing amounts of available data have led to a heightened need for representing large-scale probabilistic knowledge bases. One approach is to use a probabilistic database, a model with strong assumptions that allow for efficiently answering many interesting queries. Recent work on open-world probabilistic databases strengthens the semantics of these probabilistic databases by discarding the assumption that any information not present in the data must be false. While intuitive, these semantics are not sufficiently precise to give reasonable answers to queries. We propose overcoming these issues by using constraints to restrict this open world. We provide an algorithm for one class of queries, and establish a basic hardness result for another. Finally, we propose an efficient and tight approximation for a large class of queries.
Community-based 3-SAT Formulas with a Predefined Solution
Hu, Yamin, Luo, Wenjian, Wang, Junteng
It is crucial to generate crafted SAT formulas with predefined solutions for the testing and development of SAT solvers since many SAT formulas from real-world applications have solutions. Although some generating algorithms have been proposed to generate SAT formulas with predefined solutions, community structures of SAT formulas are not considered. We propose a 3-SAT formula generating algorithm that not only guarantees the existence of a predefined solution, but also simultaneously considers community structures and clause distributions. The proposed 3-SAT formula generating algorithm controls the quality of community structures through controlling (1) the number of clauses whose variables have a common community, which we call intra-community clauses, and (2) the number of variables that only belong to one community, which we call intra-community variables. To study the combined effect of community structures and clause distributions on the hardness of SAT formulas, we measure solving runtimes of two solvers, gluHack (a leading CDCL solver) and CPSparrow (a leading SLS solver), on the generated SAT formulas under different groups of parameter settings. Through extensive experiments, we obtain some noteworthy observations on the SAT formulas generated by the proposed algorithm: (1) The community structure has little or no effects on the hardness of SAT formulas with regard to CPSparrow but a strong effect with regard to gluHack. (2) Only when the proportion of true literals in a SAT formula in terms of the predefined solution is 0.5, SAT formulas are hard-to-solve with regard to gluHack; when this proportion is below 0.5, SAT formulas are hard-to-solve with regard to CPSparrow. (3) When the ratio of the number of clauses to that of variables is around 4.25, the SAT formulas are hard-to-solve with regard to both gluHack and CPSparrow.
Experimental Study on CTL model checking using Machine Learning
The existing core methods, which are employed by the popular CTL model checking tools, are facing the famous state explode problem. In our previous study, a method based on the Machine Learning (ML) algorithms was proposed to address this problem. However, the accuracy is not satisfactory. First, we conduct a comprehensive experiment on Graph Lab to seek the optimal accuracy using the five machine learning algorithms. Second, given the optimal accuracy, the average time is seeked. The results show that the Logistic Regressive (LR)-based approach can simulate CTL model checking with the accuracy of 98.8%, and its average efficiency is 459 times higher than that of the existing method, as well as the Boosted Tree (BT)-based approach can simulate CTL model checking with the accuracy of 98.7%, and its average efficiency is 639 times higher than that of the existing method.
Founded World Views with Autoepistemic Equilibrium Logic
Cabalar, Pedro, Fandinno, Jorge, Fariรฑas, Luis
Defined by Gelfond in 1991 (G91), epistemic specifications (or programs) are an extension of logic programming under stable models semantics that introduces subjective literals. A subjective literal allows checking whether some regular literal is true in all (or in some of) the stable models of the program, being those models collected in a set called world view. One epistemic program may yield several world views but, under the original G91 semantics, some of them resulted from selfsupported derivations. During the last eight years, several alternative approaches have been proposed to get rid of these self-supported world views. Unfortunately, their success could only be measured by studying their behaviour on a set of common examples in the literature, since no formal property of "self-supportedness" had been defined. To fill this gap, we extend in this paper the idea of unfounded set from standard logic programming to the epistemic case. We define when a world view is founded with respect to some program and propose the foundedness property for any semantics whose world views are always founded. Using counterexamples, we explain that the previous approaches violate foundedness, and proceed to propose a new semantics based on a combination of Moore's Autoepistemic Logic and Pearce's Equilibrium Logic. The main result proves that this new semantics precisely captures the set of founded G91 world views.
Making AI meaningful again
Landgrebe, Jobst, Smith, Barry
Artificial intelligence (AI) research enjoyed an initial period of enthusiasm in the 1970s and 80s. But this enthusiasm was tempered by a long interlude of frustration when genuinely useful AI applications failed to be forthcoming. Today, we are experiencing once again a period of enthusiasm, fired above all by the successes of the technology of deep neural networks or deep machine learning. In this paper we draw attention to what we take to be serious problems underlying current views of artificial intelligence encouraged by these successes, especially in the domain of language processing. We then show an alternative approach to language-centric AI, in which we identify a role for philosophy.
Was ist eine Professur fuer Kuenstliche Intelligenz?
Kersting, Kristian, Peters, Jan, Rothkopf, Constantin
Conf. on Information and Knowledge Management (CIKM) h5 49 International Conference on Artificial Intelligence and Statistics (AISTATS) h5 43 Data Mining and Knowledge Discovery Journal (DMKD) h5 35 Neural Computation h5 34 SIAM International Conference on Data Mining (SDM) h5 33 European Conference on Machine Learning and Knowledge Discovery in Databases (ECML PKDD) h5 30 European Conference on Information Retrieval (ECIR) h5 26 Pacific-Asia Conference on Knowledge Discovery and Data Mining (PAKDD) h5 23 CORE B ACM Conference on Recommender Systems (RecSys) h5 40 International Joint Conference on Neural Networks (IJCNN) h5 32 Neural Processing Letters h5 23 Information Retrieval h5 20 International Conference on Artificial Neural Networks (ICANN) h5 14 International Conference in Inductive Logic Programming (ILP) h5 - CORE Unranked Asian Conference on Machine Learning (ACML) h5 13 International Conference on Learning Representations (ICLR) h5 - Wahrnehmung und Sehen Die Fรคhigkeit zur Verarbeitung visueller Information ist eine Grundbedingung fรผr kรผnstliche Intelligenzen.
Readings in Medical Artificial Intelligence: The First Decade
A survey of early work exploring how AI can be used in medicine, with somewhat more technical expositions than in the complementary volume Artificial Intelligence in Medicine."Each chapter is preceded by a brief introduction that outlines our view of its contribution to the field, the reason it was selected for inclusion in this volume, an overview of its content, and a discussion of how the work evolved after the article appeared and how it relates to other chapters in the book.
Verifiably Safe Off-Model Reinforcement Learning
Fulton, Nathan, Platzer, Andre
The desire to use reinforcement learning in safety-critical settings has inspired a recent interest in formal methods for learning algorithms. Existing formal methods for learning and optimization primarily consider the problem of constrained learning or constrained optimization. Given a single correct model and associated safety constraint, these approaches guarantee efficient learning while provably avoiding behaviors outside the safety constraint. Acting well given an accurate environmental model is an important pre-requisite for safe learning, but is ultimately insufficient for systems that operate in complex heterogeneous environments. This paper introduces verification-preserving model updates, the first approach toward obtaining formal safety guarantees for reinforcement learning in settings where multiple environmental models must be taken into account. Through a combination of design-time model updates and runtime model falsification, we provide a first approach toward obtaining formal safety proofs for autonomous systems acting in heterogeneous environments.