A structured understanding of our world in terms of objects, relations, and hierarchies is an important component of human cognition. Learning such a structured world model from raw sensory data remains a challenge. As a step towards this goal, we introduce Contrastively-trained Structured World Models (C-SWMs). C-SWMs utilize a contrastive approach for representation learning in environments with compositional structure. We structure each state embedding as a set of object representations and their relations, modeled by a graph neural network. This allows objects to be discovered from raw pixel observations without direct supervision as part of the learning process. We evaluate C-SWMs on compositional environments involving multiple interacting objects that can be manipulated independently by an agent, simple Atari games, and a multi-object physics simulation. Our experiments demonstrate that C-SWMs can overcome limitations of models based on pixel reconstruction and outperform typical representatives of this model class in highly structured environments, while learning interpretable object-based representations.

A basic understanding of these ideas is essential to any JavaScript developer wishing to analyze and build great software solutions. You'll discover how to implement data structures such as hash tables, linked lists, stacks, queues, trees, and graphs. You'll also learn how a URL shortener, such as bit.ly, is developed and what is happening to the data as a PDF is uploaded to a webpage. This book covers the practical applications of data structures and algorithms to encryption, searching, sorting, and pattern matching. It is crucial for JavaScript developers to understand how data structures work and how to design algorithms.

Scaling Bayesian optimisation (BO) to high-dimensional search spaces is a active and open research problems particularly when no assumptions are made on function structure. The main reason is that at each iteration, BO requires to find global maximisation of acquisition function, which itself is a non-convex optimization problem in the original search space. With growing dimensions, the computational budget for this maximisation gets increasingly short leading to inaccurate solution of the maximisation. This inaccuracy adversely affects both the convergence and the efficiency of BO. We propose a novel approach where the acquisition function only requires maximisation on a discrete set of low dimensional subspaces embedded in the original high-dimensional search space. Our method is free of any low dimensional structure assumption on the function unlike many recent high-dimensional BO methods. Optimising acquisition function in low dimensional subspaces allows our method to obtain accurate solutions within limited computational budget. We show that in spite of this convenience, our algorithm remains convergent. In particular, cumulative regret of our algorithm only grows sub-linearly with the number of iterations. More importantly, as evident from our regret bounds, our algorithm provides a way to trade the convergence rate with the number of subspaces used in the optimisation. Finally, when the number of subspaces is "sufficiently large", our algorithm's cumulative regret is at most $\mathcal{O}^{*}(\sqrt{T\gamma_T})$ as opposed to $\mathcal{O}^{*}(\sqrt{DT\gamma_T})$ for the GP-UCB of Srinivas et al. (2012), reducing a crucial factor $\sqrt{D}$ where $D$ being the dimensional number of input space.

Inhibition can take place at the level of neurotransmitters in the synaptic cleft, neurons can inhibit each other's fire rate, it can be s h own at a physiological level - for instance by measuring the EEG, and finally it can be investigated on a purely behavioral level. Behavioral inhibition typically means something like'making a content/action less accessible or suppressing it altogether' in order to enhance processing of relevant information . In cognition, thus, the concept of inhibition implies cognitive mechanisms that actively lower currently irrelevant or inter fering information. Psychological theories that posit the existence of inhibitory mechanisms in our mind have elicited much research across diverse fields of C ognitive P sychology like perception, attention, action control, and memory but have also been tra nsferred to other research fields like D evelopmental P sychology as, fo r instance, understanding the aging brain or the developing brain is closely linked to understanding how the brain handles irrelevant or interfering information - that is how or whether the brain can inhibit such information. The two areas in Cognitive Psychology in which inhibition is traditionally investigated to the largest extent are the research fields of attention and memory. In attention research, typically the interference due to distracting stimuli or actions is analyzed in experimental paradigms that try to tap a specific form of cognitive inhibition. For example, in the Negative Priming task (for a review, Frings, Schneider, & Fox, 2015) it is typically analyzed how an irrelevant distractor stimulus is inhibited. In the cuing task that elicits the inhibition of return effect (Posner, Choate, Rafal, & Vaughn, 1985) it is typically analyzed how an irrelevant location is inhibited. In task switchin g (Kiesel et al., 2010) lowering competition by a just previously performed task while currently executing a novel task is achieved by inhibiting that previous task.

The ability to persist in the spacial environment is, not only in the robotic context, an essential feature. Positional knowledge is one of the most important aspects of space and a number of methods to represent these information have been developed in the in the research area of spatial cognition. The basic qualitative spatial representation and reasoning techniques are presented in this thesis and several calculi are briefly reviewed. Features and applications of qualitative calculi are summarized. A new calculus for representing and reasoning about qualitative spatial orientation and distances is being designed. It supports an arbitrary level of granularity over ternary relations of points. Ways of improving the complexity of the composition are shown and an implementation of the calculus demonstrates its capabilities. Existing qualitative spatial calculi of positional information are compared to the new approach and possibilities for future research are outlined.

The abstraction levels represent a general progression from the test cases through available and derived values to partial and complete solutions. The abstraction levels include: - test cases; - input and output elements; - derived values (symbolic and numeric); - code fragments; - target values; - case solutions; - case set solutions; - program solutions; - solution code. The data on the blackboard represents a set of more or less promising solution fragments at different stages of identification, characterisation and elaboration. It is worth noting that progression from test cases to solution code is not a strictly linear process. Instead knowledge sources respond to changes at one or more specific abstraction levels to produce, enhance or remove elements on different levels. The blackboard model allows this to happen in more or less any order.

Answering complex questions involving multiple entities and relations is a challenging task. Logically, the answer to a complex question should be derived by decomposing the complex question into multiple simple sub-questions and then answering those sub-questions. Existing work has followed this strategy but has not attempted to optimize the order how those sub-questions are answered. As a result, the sub-questions are answered in an arbitrary order, leading to larger search space and higher risk of missing an answer. In this paper, we propose a novel reinforcement learning (RL) approach to answering complex questions that can learn a policy to dynamically decide which sub-question should be answered at each state of reasoning. We leverage the expected value-variance criterion to enable the learned policy to balance between the risk and utility of answering a sub-question. Experiment results show that the RL approach can substantially improve the optimal-ity of ordering the sub-questions, leading to improved accuracy of question answering. The proposed method for learning to order sub-questions is general and can thus be potentially combined with many existing ideas for answering complex questions to enhance their performance. Introduction Real-world questions can be complex, involving multiple interrelated entities and relations, which we refer to as complex questions . For example, "who writes Harry Potter" is a simple question that only involves a single entity and a relation, while "Which city is the filming location of the book written by J.K.Rowling and held Olympics?" is a complex question, which consists of multiple entities and relations. How to automatically answer such complex questions is a significant scientific challenge because it requires a system to capture the dependencies between different components of the questions and reason over them. Recently, some recent work has attempted to tackle such complex questions (Talmor and Berant 2018; Iyyer, Yih, and Chang 2016; Min et al. 2019; Zhang et al. 2019), usually by decomposing a complex question into a sequence of simple questions and answering them based on a computation tree derived from the original question that can capture the dependency between sub-questions as shown in Figure 1.

Standardization of solver input languages has been a main dr iver for the growth of several areas within knowledge representation and reasoning, fostering the exploitation in actual applications. In this document we present the ASP-Core-2 standard input language for Answer Set Programming, which h as been adopted in ASP Competition events since 2013. KEYWORDS: Answer Set Programming, Standard Language, Knowledge Rep resentation and Reasoning, Standardization 2 Calimeri et al. 1 Introduction The process of standardizing the input languages of solvers for knowledge representation and reasoning research areas has been of utmost importance for the growth o f the related research communities: this has been the case for, e.g., the CNF-DIMACS format for SA T, th en extended to describe input formats for Max-SA T and QBF problems, the OPB format for pseudo-Boolean problems, somehow at the intersection between the CNF-DIMACS format and the LP format for Integer L inear Programming, the XCSP3 format for CP solving, SMT -LIB format for SMT solving, and the STRIP S/ PDDL language for automatic planning. The availability of such common input languages have l ed to the development of e ffi cient solvers in di ff erent KR communities, through a series of solver competitio ns that have pushed the adoption of these standards. The availability of e ffi cient solvers, together with a presence of a common interfac e language, has helped the exploitation of these methodologies in appli cations. The same has happened for Answer Set Programming (ASP) (Brew ka et al. 2011), a well-known approach to knowledge representation and reasoning with root s in the areas of logic programming and nonmonotonic reasoning (Gelfond and Lifschitz 1991), through the development of the ASP-Core language (Calimeri et al. 2011). The first ASP-Core version was a rule-based language whose syntax stems from plain Datalog and Prolog, and was a conservative extension t o the non-ground case of the Core language adopted in the First ASP Competition held in 2002 during the D agstuhl Seminar "Nonmonotonic Reasoning, Answer Set Programming and Constraints"

Starting from sensory, measured inputs, this is done by gradually transforming across different levels of abstraction: from perceptual data, unstructured in nature (e.g.

Traditional first-order logic (FOL) reasoning systems usually rely on manual heuristics for proof guidance. We propose TRAIL: a system that learns to perform proof guidance using reinforcement learning. A key design principle of our system is that it is general enough to allow transfer to problems in different domains that do not share the same vocabulary of the training set. To do so, we developed a novel representation of the internal state of a prover in terms of clauses and inference actions, and a novel neural-based attention mechanism to learn interactions between clauses. We demonstrate that this approach enables the system to generalize from training to test data across domains with different vocabularies, suggesting that the neural architecture in TRAIL is well suited for representing and processing of logical formalisms.