104 research outputs found
Neurosymbolic AI for Reasoning on Graph Structures: A Survey
Neurosymbolic AI is an increasingly active area of research which aims to
combine symbolic reasoning methods with deep learning to generate models with
both high predictive performance and some degree of human-level
comprehensibility. As knowledge graphs are becoming a popular way to represent
heterogeneous and multi-relational data, methods for reasoning on graph
structures have attempted to follow this neurosymbolic paradigm. Traditionally,
such approaches have utilized either rule-based inference or generated
representative numerical embeddings from which patterns could be extracted.
However, several recent studies have attempted to bridge this dichotomy in ways
that facilitate interpretability, maintain performance, and integrate expert
knowledge. Within this article, we survey a breadth of methods that perform
neurosymbolic reasoning tasks on graph structures. To better compare the
various methods, we propose a novel taxonomy by which we can classify them.
Specifically, we propose three major categories: (1) logically-informed
embedding approaches, (2) embedding approaches with logical constraints, and
(3) rule-learning approaches. Alongside the taxonomy, we provide a tabular
overview of the approaches and links to their source code, if available, for
more direct comparison. Finally, we discuss the applications on which these
methods were primarily used and propose several prospective directions toward
which this new field of research could evolve.Comment: 21 pages, 8 figures, 1 table, currently under review. Corresponding
GitHub page here: https://github.com/NeSymGraph
From Statistical Relational to Neurosymbolic Artificial Intelligence: a Survey
This survey explores the integration of learning and reasoning in two
different fields of artificial intelligence: neurosymbolic and statistical
relational artificial intelligence. Neurosymbolic artificial intelligence
(NeSy) studies the integration of symbolic reasoning and neural networks, while
statistical relational artificial intelligence (StarAI) focuses on integrating
logic with probabilistic graphical models. This survey identifies seven shared
dimensions between these two subfields of AI. These dimensions can be used to
characterize different NeSy and StarAI systems. They are concerned with (1) the
approach to logical inference, whether model or proof-based; (2) the syntax of
the used logical theories; (3) the logical semantics of the systems and their
extensions to facilitate learning; (4) the scope of learning, encompassing
either parameter or structure learning; (5) the presence of symbolic and
subsymbolic representations; (6) the degree to which systems capture the
original logic, probabilistic, and neural paradigms; and (7) the classes of
learning tasks the systems are applied to. By positioning various NeSy and
StarAI systems along these dimensions and pointing out similarities and
differences between them, this survey contributes fundamental concepts for
understanding the integration of learning and reasoning.Comment: To appear in Artificial Intelligence. Shorter version at IJCAI 2020
survey track, https://www.ijcai.org/proceedings/2020/0688.pd
Analysis Of A Neuro-Fuzzy Approach Of Air Pollution: Building A Case Study
This work illustrates the necessity of an Artificial Intelligence (AI)-based approach of air quality in urban and industrial areas. Some related results of Artificial Neural Networks (ANNs) and Fuzzy Logic (FL) for environmental data are considered: ANNs are proposed to the problem of short-term predicting of air pollutant concentrations in urban/industrial areas, with a special focus in the south-eastern Romania. The problems of designing a database about air quality in an urban/industrial area are discussed. First results confirm ANNs as an improvement of classical models and show the utility of ANNs in a well built air monitoring center
A Review of Symbolic, Subsymbolic and Hybrid Methods for Sequential Decision Making
The field of Sequential Decision Making (SDM) provides tools for solving
Sequential Decision Processes (SDPs), where an agent must make a series of
decisions in order to complete a task or achieve a goal. Historically, two
competing SDM paradigms have view for supremacy. Automated Planning (AP)
proposes to solve SDPs by performing a reasoning process over a model of the
world, often represented symbolically. Conversely, Reinforcement Learning (RL)
proposes to learn the solution of the SDP from data, without a world model, and
represent the learned knowledge subsymbolically. In the spirit of
reconciliation, we provide a review of symbolic, subsymbolic and hybrid methods
for SDM. We cover both methods for solving SDPs (e.g., AP, RL and techniques
that learn to plan) and for learning aspects of their structure (e.g., world
models, state invariants and landmarks). To the best of our knowledge, no other
review in the field provides the same scope. As an additional contribution, we
discuss what properties an ideal method for SDM should exhibit and argue that
neurosymbolic AI is the current approach which most closely resembles this
ideal method. Finally, we outline several proposals to advance the field of SDM
via the integration of symbolic and subsymbolic AI
Discovering logical knowledge in non-symbolic domains
Deep learning and symbolic artificial intelligence remain the two main paradigms in Artificial Intelligence (AI), each presenting their own strengths and weaknesses. Artificial agents should integrate both of these aspects of AI in order to show general intelligence and solve complex problems in real-world scenarios; similarly to how humans use both the analytical left side and the intuitive right side of their brain in their lives. However, one of the main obstacles hindering this integration is the Symbol Grounding Problem [144], which is the capacity to map physical world observations to a set of symbols. In this thesis, we combine symbolic reasoning and deep learning in order to better represent and reason with abstract knowledge. In particular, we focus on solving non-symbolic-state Reinforcement Learning environments using a symbolic logical domain. We consider different configurations: (i) unknown knowledge of both the symbol grounding function and the symbolic logical domain, (ii) unknown knowledge of the symbol grounding function and prior knowledge of the domain, (iii) imperfect knowledge of the symbols grounding function and unknown knowledge of the domain. We develop algorithms and neural network architectures that are general enough to be applied to different kinds of environments, which we test on both continuous-state control problems and image-based environments. Specifically, we develop two kinds of architectures: one for Markovian RL tasks and one for non-Markovian RL domains. The first is based on model-based RL and representation learning, and is inspired by the substantial prior work in state abstraction for RL [115]. The second is mainly based on recurrent neural networks and continuous relaxations of temporal logic domains. In particular, the first approach extracts a symbolic STRIPS-like abstraction for control problems. For the second approach, we explore connections between recurrent neural networks and finite state machines, and we define Visual Reward Machines, an extension to non-symbolic domains of Reward Machines [27], which are a popular approach to non-Markovian RL tasks
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Neurosymbolic AI: the 3rd wave
Current advances in Artificial Intelligence (AI) and Machine Learning have achieved unprecedented impact across research communities and industry. Nevertheless, concerns around trust, safety, interpretability and accountability of AI were raised by influential thinkers. Many identified the need for well-founded knowledge representation and reasoning to be integrated with deep learning and for sound explainability. Neurosymbolic computing has been an active area of research for many years seeking to bring together robust learning in neural networks with reasoning and explainability by offering symbolic representations for neural models. In this paper, we relate recent and early research in neurosymbolic AI with the objective of identifying the most important ingredients of neurosymbolic AI systems. We focus on research that integrates in a principled way neural network-based learning with symbolic knowledge representation and logical reasoning. Finally, this review identifies promising directions and challenges for the next decade of AI research from the perspective of neurosymbolic computing, commonsense reasoning and causal explanation
Do Artificial Intelligence Systems Understand?
Are intelligent machines really intelligent? Is the underlying philosophical
concept of intelligence satisfactory for describing how the present systems
work? Is understanding a necessary and sufficient condition for intelligence?
If a machine could understand, should we attribute subjectivity to it? This
paper addresses the problem of deciding whether the so-called "intelligent
machines" are capable of understanding, instead of merely processing signs. It
deals with the relationship between syntaxis and semantics. The main thesis
concerns the inevitability of semantics for any discussion about the
possibility of building conscious machines, condensed into the following two
tenets: "If a machine is capable of understanding (in the strong sense), then
it must be capable of combining rules and intuitions"; "If semantics cannot be
reduced to syntaxis, then a machine cannot understand." Our conclusion states
that it is not necessary to attribute understanding to a machine in order to
explain its exhibited "intelligent" behavior; a merely syntactic and
mechanistic approach to intelligence as a task-solving tool suffices to justify
the range of operations that it can display in the current state of
technological development
Grounding LTLf specifications in images
A critical challenge in neurosymbolic approaches is to handle the symbol grounding problem without direct supervision. That is mapping high-dimensional raw data into an interpretation over a finite set of abstract concepts with a known meaning, without using labels. In this work, we ground symbols into sequences of images by exploiting symbolic logical knowledge in the form of Linear Temporal Logic over finite traces (LTLf) formulas, and sequence-level labels expressing if a sequence of images is compliant or not with the given formula. Our approach is based on translating the LTLf formula into an equivalent
deterministic finite automaton (DFA) and interpreting the latter in fuzzy logic. Experiments show that our system outperforms recurrent neural networks in sequence classification and can reach high image classification accuracy without being trained with any single-image label
Towards Cognitive AI Systems: a Survey and Prospective on Neuro-Symbolic AI
The remarkable advancements in artificial intelligence (AI), primarily driven
by deep neural networks, have significantly impacted various aspects of our
lives. However, the current challenges surrounding unsustainable computational
trajectories, limited robustness, and a lack of explainability call for the
development of next-generation AI systems. Neuro-symbolic AI (NSAI) emerges as
a promising paradigm, fusing neural, symbolic, and probabilistic approaches to
enhance interpretability, robustness, and trustworthiness while facilitating
learning from much less data. Recent NSAI systems have demonstrated great
potential in collaborative human-AI scenarios with reasoning and cognitive
capabilities. In this paper, we provide a systematic review of recent progress
in NSAI and analyze the performance characteristics and computational operators
of NSAI models. Furthermore, we discuss the challenges and potential future
directions of NSAI from both system and architectural perspectives.Comment: Workshop on Systems for Next-Gen AI Paradigms, 6th Conference on
Machine Learning and Systems (MLSys), June 4-8, 2023, Miami, FL, US
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