Problem Solving
Scale-Adaptive Balancing of Exploration and Exploitation in Classical Planning
Wissow, Stephen, Asai, Masataro
Balancing exploration and exploitation has been an important problem in both game tree search and automated planning. However, while the problem has been extensively analyzed within the Multi-Armed Bandit (MAB) literature, the planning community has had limited success when attempting to apply those results. We show that a more detailed theoretical understanding of MAB literature helps improve existing planning algorithms that are based on Monte Carlo Tree Search (MCTS) / Trial Based Heuristic Tree Search (THTS). In particular, THTS uses UCB1 MAB algorithms in an ad hoc manner, as UCB1's theoretical requirement of fixed bounded support reward distributions is not satisfied within heuristic search for classical planning. The core issue lies in UCB1's lack of adaptations to the different scales of the rewards. We propose GreedyUCT-Normal, a MCTS/THTS algorithm with UCB1-Normal bandit for agile classical planning, which handles distributions with different scales by taking the reward variance into consideration, and resulted in an improved algorithmic performance (more plans found with less node expansions) that outperforms Greedy Best First Search and existing MCTS/THTS-based algorithms (GreedyUCT,GreedyUCT*).
Learning Differentiable Logic Programs for Abstract Visual Reasoning
Shindo, Hikaru, Pfanschilling, Viktor, Dhami, Devendra Singh, Kersting, Kristian
Visual reasoning is essential for building intelligent agents that understand the world and perform problem-solving beyond perception. Differentiable forward reasoning has been developed to integrate reasoning with gradient-based machine learning paradigms. However, due to the memory intensity, most existing approaches do not bring the best of the expressivity of first-order logic, excluding a crucial ability to solve abstract visual reasoning, where agents need to perform reasoning by using analogies on abstract concepts in different scenarios. To overcome this problem, we propose NEUro-symbolic Message-pAssiNg reasoNer (NEUMANN), which is a graph-based differentiable forward reasoner, passing messages in a memory-efficient manner and handling structured programs with functors. Moreover, we propose a computationally-efficient structure learning algorithm to perform explanatory program induction on complex visual scenes. To evaluate, in addition to conventional visual reasoning tasks, we propose a new task, visual reasoning behind-the-scenes, where agents need to learn abstract programs and then answer queries by imagining scenes that are not observed. We empirically demonstrate that NEUMANN solves visual reasoning tasks efficiently, outperforming neural, symbolic, and neuro-symbolic baselines.
Knowledge-Driven Robot Program Synthesis from Human VR Demonstrations
Alt, Benjamin, Kenfack, Franklin Kenghagho, Haidu, Andrei, Katic, Darko, Jäkel, Rainer, Beetz, Michael
Aging societies, labor shortages and increasing wage costs call for assistance robots capable of autonomously performing a wide array of real-world tasks. Such open-ended robotic manipulation requires not only powerful knowledge representations and reasoning (KR&R) algorithms, but also methods for humans to instruct robots what tasks to perform and how to perform them. In this paper, we present a system for automatically generating executable robot control programs from human task demonstrations in virtual reality (VR). We leverage common-sense knowledge and game engine-based physics to semantically interpret human VR demonstrations, as well as an expressive and general task representation and automatic path planning and code generation, embedded into a state-of-the-art cognitive architecture. We demonstrate our approach in the context of force-sensitive fetch-and-place for Figure 1: We propose a knowledge-driven approach to convert human a robotic shopping assistant.
The Integer Linear Programming Inference Cookbook
Effective decision-making requires the use of knowledge. This has been a clear, and long-standing principle in AI research, as reflected, for example, in the seminal early work on knowledge and AI--summarized by Brachman and Levesque (1985)--and the thriving Knowledge Representation and Reasoning and the Uncertainty in AI communities. However, the message has been somewhat diluted as data-driven statistical learning has become increasingly pervasive across AI. Nevertheless, the idea that reasoning and learning need to work together (Khardon and Roth, 1996; Roth, 1996) and that knowledge representation is a crucial bridge between them has not been lost. One area where the link between learning, representation, and reasoning has been shown to be essential and has been studied extensively is Natural Language Processing (NLP), and in particular, the area of Structured Output Prediction within NLP. In structured problems, there is a need to assign values to multiple random variables that are interrelated. Examples include extracting multiple relations among entities in a document, where a the two arguments for a relation such as born-in cannot refer to people, or co-reference resolution, where gender agreement must be maintained when determining that a specific pronoun refers to a given entity. In these, and many other such problems, it is natural to represent knowledge as Boolean functions over propositional variables. These functions would express knowledge, for example, of the form "if the relation between two entities is born-in, then its arguments must be a person and a location" (formalized as functions such as x
Hierarchical Neural Coding for Controllable CAD Model Generation
Xu, Xiang, Jayaraman, Pradeep Kumar, Lambourne, Joseph G., Willis, Karl D. D., Furukawa, Yasutaka
This paper presents a novel generative model for Computer Aided Design (CAD) that 1) represents high-level design concepts of a CAD model as a three-level hierarchical tree of neural codes, from global part arrangement down to local curve geometry; and 2) controls the generation or completion of CAD models by specifying the target design using a code tree. Concretely, a novel variant of a vector quantized VAE with "masked skip connection" extracts design variations as neural codebooks at three levels. Two-stage cascaded auto-regressive transformers learn to generate code trees from incomplete CAD models and then complete CAD models following the intended design. Extensive experiments demonstrate superior performance on conventional tasks such as unconditional generation while enabling novel interaction capabilities on conditional generation tasks.
On Computational Mechanisms for Shared Intentionality, and Speculation on Rationality and Consciousness
A singular attribute of humankind is our ability to undertake novel, cooperative behavior, or teamwork. This requires that we can communicate goals, plans, and ideas between the brains of individuals to create shared intentionality. Using the information processing model of David Marr, I derive necessary characteristics of basic mechanisms to enable shared intentionality between prelinguistic computational agents and indicate how these could be implemented in present-day AI-based robots. More speculatively, I suggest the mechanisms derived by this thought experiment apply to humans and extend to provide explanations for human rationality and aspects of intentional and phenomenal consciousness that accord with observation. This yields what I call the Shared Intentionality First Theory (SIFT) for rationality and consciousness. The significance of shared intentionality has been recognized and advocated previously, but typically from a sociological or behavioral point of view. SIFT complements prior work by applying a computer science perspective to the underlying mechanisms.
China takes divide-and-conquer approach on 'de-risking' with appeals to CEOs
When the U.S. first embraced "de-risking" to get Europe on board with measures to deny key technology to China, officials in Beijing dismissed the term as no different than decoupling. Now they are trying a new strategy: redefining the concept. Chinese Premier Li Qiang last week acknowledged the legitimacy of de-risking while speaking to CEOs on a trip to Germany, but said it should be decided by business leaders instead of governments. He also warned that risks shouldn't be "exaggerated" -- opening a discussion on what exactly poses a serious threat to national security. Li touched on the theme again Tuesday at a high-profile economic forum in China known as "Summer Davos," where he told delegates "if there is risk in a certain industry, it's not the call or decision of a particular organization or a single government.
Lightweight Modeling of User Context Combining Physical and Virtual Sensor Data
Campana, Mattia Giovanni, Chatzopoulos, Dimitris, Delmastro, Franca, Hui, Pan
The multitude of data generated by sensors available on users' mobile devices, combined with advances in machine learning techniques, support context-aware services in recognizing the current situation of a user (i.e., physical context) and optimizing the system's personalization features. However, context-awareness performances mainly depend on the accuracy of the context inference process, which is strictly tied to the availability of large-scale and labeled datasets. In this work, we present a framework developed to collect datasets containing heterogeneous sensing data derived from personal mobile devices. The framework has been used by 3 voluntary users for two weeks, generating a dataset with more than 36K samples and 1331 features. We also propose a lightweight approach to model the user context able to efficiently perform the entire reasoning process on the user mobile device. To this aim, we used six dimensionality reduction techniques in order to optimize the context classification. Experimental results on the generated dataset show that we achieve a 10x speed up and a feature reduction of more than 90% while keeping the accuracy loss less than 3%.
PhD Thesis: Exploring the role of (self-)attention in cognitive and computer vision architecture
We investigate the role of attention and memory in complex reasoning tasks. We analyze Transformer-based self-attention as a model and extend it with memory. By studying a synthetic visual reasoning test, we refine the taxonomy of reasoning tasks. Incorporating self-attention with ResNet50, we enhance feature maps using feature-based and spatial attention, achieving efficient solving of challenging visual reasoning tasks. Our findings contribute to understanding the attentional needs of SVRT tasks. Additionally, we propose GAMR, a cognitive architecture combining attention and memory, inspired by active vision theory. GAMR outperforms other architectures in sample efficiency, robustness, and compositionality, and shows zero-shot generalization on new reasoning tasks.
Deep R Programming
Deep R Programming is a comprehensive and in-depth introductory course on one of the most popular languages for data science. It equips ambitious students, professionals, and researchers with the knowledge and skills to become independent users of this potent environment so that they can tackle any problem related to data wrangling and analytics, numerical computing, statistics, and machine learning. This textbook is a non-profit project. Its online and PDF versions are freely available at