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The SCC-recursiveness Principle in Fuzzy Argumentation Frameworks

arXiv.org Artificial Intelligence

Dung's abstract argumentation theory plays a guiding role in the field of formal argumentation. The properties of argumentation semantics have been deeply explored in the previous literature. The SCC-recursiveness principle is a property of the extensions which relies on the graph-theoretical notion of strongly connected components. It provides a general recursive schema for argumentation semantics, which is an efficient and incremental algorithm for computing the argumentation semantics. However, in argumentation frameworks with uncertain arguments and uncertain attack relation, the SCC-recursive theory is absence. This paper is an exploration of the SCC-recursive theory in fuzzy argumentation frameworks (FAFs), which add numbers as fuzzy degrees to the arguments and attacks. In this paper, in order to extend the SCC-recursiveness principle to FAFs, we first modify the reinstatement principle and directionality principle to fit the FAFs. Then the SCC-recursiveness principle in FAFs is formalized by the modified principles. Additionally, some illustrating examples show that the SCC-recursiveness principle also provides an efficient and incremental algorithm for simplify the computation of argumentation semantics in FAFs.


Pessimism About Unknown Unknowns Inspires Conservatism

arXiv.org Artificial Intelligence

If we could define the set of all bad outcomes, we could hard-code an agent which avoids them; however, in sufficiently complex environments, this is infeasible. We do not know of any general-purpose approaches in the literature to avoiding novel failure modes. Motivated by this, we define an idealized Bayesian reinforcement learner which follows a policy that maximizes the worst-case expected reward over a set of world-models. We call this agent pessimistic, since it optimizes assuming the worst case. A scalar parameter tunes the agent's pessimism by changing the size of the set of world-models taken into account. Our first main contribution is: given an assumption about the agent's model class, a sufficiently pessimistic agent does not cause "unprecedented events" with probability $1-\delta$, whether or not designers know how to precisely specify those precedents they are concerned with. Since pessimism discourages exploration, at each timestep, the agent may defer to a mentor, who may be a human or some known-safe policy we would like to improve. Our other main contribution is that the agent's policy's value approaches at least that of the mentor, while the probability of deferring to the mentor goes to 0. In high-stakes environments, we might like advanced artificial agents to pursue goals cautiously, which is a non-trivial problem even if the agent were allowed arbitrary computing power; we present a formal solution.


Efficient Reasoning in Regular Boardgames

arXiv.org Artificial Intelligence

We present the technical side of reasoning in Regular Boardgames (RBG) language -- a universal General Game Playing (GGP) formalism for the class of finite deterministic games with perfect information, encoding rules in the form of regular expressions. RBG serves as a research tool that aims to aid in the development of generalized algorithms for knowledge inference, analysis, generation, learning, and playing games. In all these tasks, both generality and efficiency are important. In the first part, this paper describes optimizations used by the RBG compiler. The impact of these optimizations ranges from 1.7 to even 33-fold efficiency improvement when measuring the number of possible game playouts per second. Then, we perform an in-depth efficiency comparison with three other modern GGP systems (GDL, Ludii, Ai Ai). We also include our own highly optimized game-specific reasoners to provide a point of reference of the maximum speed. Our experiments show that RBG is currently the fastest among the abstract general game playing languages, and its efficiency can be competitive to common interface-based systems that rely on handcrafted game-specific implementations. Finally, we discuss some issues and methodology of computing benchmarks like this.


DreamCoder: Growing generalizable, interpretable knowledge with wake-sleep Bayesian program learning

arXiv.org Artificial Intelligence

Expert problem-solving is driven by powerful languages for thinking about problems and their solutions. Acquiring expertise means learning these languages -- systems of concepts, alongside the skills to use them. We present DreamCoder, a system that learns to solve problems by writing programs. It builds expertise by creating programming languages for expressing domain concepts, together with neural networks to guide the search for programs within these languages. A ``wake-sleep'' learning algorithm alternately extends the language with new symbolic abstractions and trains the neural network on imagined and replayed problems. DreamCoder solves both classic inductive programming tasks and creative tasks such as drawing pictures and building scenes. It rediscovers the basics of modern functional programming, vector algebra and classical physics, including Newton's and Coulomb's laws. Concepts are built compositionally from those learned earlier, yielding multi-layered symbolic representations that are interpretable and transferrable to new tasks, while still growing scalably and flexibly with experience.


Index Selection for NoSQL Database with Deep Reinforcement Learning

arXiv.org Artificial Intelligence

We propose a new approach of NoSQL database index selection. For different workloads, we select different indexes and their different parameters to optimize the database performance. The approach builds a deep reinforcement learning model to select an optimal index for a given fixed workload and adapts to a changing workload. Experimental results show that, Deep Reinforcement Learning Index Selection Approach (DRLISA) has improved performance to varying degrees according to traditional single index structures.


COMPOSE: Cross-Modal Pseudo-Siamese Network for Patient Trial Matching

arXiv.org Artificial Intelligence

Clinical trials play important roles in drug development but often suffer from expensive, inaccurate and insufficient patient recruitment. The availability of massive electronic health records (EHR) data and trial eligibility criteria (EC) bring a new opportunity to data driven patient recruitment. One key task named patient-trial matching is to find qualified patients for clinical trials given structured EHR and unstructured EC text (both inclusion and exclusion criteria). How to match complex EC text with longitudinal patient EHRs? How to embed many-to-many relationships between patients and trials? How to explicitly handle the difference between inclusion and exclusion criteria? In this paper, we proposed CrOss-Modal PseudO-SiamEse network (COMPOSE) to address these challenges for patient-trial matching. One path of the network encodes EC using convolutional highway network. The other path processes EHR with multi-granularity memory network that encodes structured patient records into multiple levels based on medical ontology. Using the EC embedding as query, COMPOSE performs attentional record alignment and thus enables dynamic patient-trial matching. COMPOSE also introduces a composite loss term to maximize the similarity between patient records and inclusion criteria while minimize the similarity to the exclusion criteria. Experiment results show COMPOSE can reach 98.0% AUC on patient-criteria matching and 83.7% accuracy on patient-trial matching, which leads 24.3% improvement over the best baseline on real-world patient-trial matching tasks.


Symbolic Logic meets Machine Learning: A Brief Survey in Infinite Domains

arXiv.org Artificial Intelligence

The tension between deduction and induction is perhaps the most fundamental issue in areas such as philosophy, cognition and artificial intelligence (AI). The deduction camp concerns itself with questions about the expressiveness of formal languages for capturing knowledge about the world, together with proof systems for reasoning from such knowledge bases. The learning camp attempts to generalize from examples about partial descriptions about the world. In AI, historically, these camps have loosely divided the development of the field, but advances in cross-over areas such as statistical relational learning, neuro-symbolic systems, and high-level control have illustrated that the dichotomy is not very constructive, and perhaps even ill-formed. In this article, we survey work that provides further evidence for the connections between logic and learning. Our narrative is structured in terms of three strands: logic versus learning, machine learning for logic, and logic for machine learning, but naturally, there is considerable overlap. We place an emphasis on the following "sore" point: there is a common misconception that logic is for discrete properties, whereas probability theory and machine learning, more generally, is for continuous properties. We report on results that challenge this view on the limitations of logic, and expose the role that logic can play for learning in infinite domains.


Formal Verification of End-to-End Learning in Cyber-Physical Systems: Progress and Challenges

arXiv.org Artificial Intelligence

Autonomous systems - such as cars, planes, and trains - must come with strong safety guarantees. These systems are cyber-physical, in the sense that their safety depends crucially upon the way in which their software ("cyber") components interact with their kinetic components. Cyber-physical systems (CPS) analysis tools can verify the safety of CPS by stating correctness specifications in a formal language and then verifying - via computer-checked proof - that safety-critical software components respect these specifications. Existing approaches toward formally verifying the correctness of cyber-physical systems focus primarily on constructing formal safety proofs about classical low-dimensional models of control systems. For example, the safety of an adaptive cruise control system might be established by modeling the dynamics of two cars in terms of their positions and velocities and then proving that a control policy preserves safe separation between all cars on the road for any time horizon [15]. Researchers have employed a similar approach for ensuring the correctness of proposed FAA aircraft collision avoidance protocols [12], the European Train Control System [20], and quadcopters [21]. These proofs are typically constructed and checked using a cyber-physical systems verification tool such as Flow* [4], KeYmaera X [8], or SpaceEx [6]. CPS verification tools can provide very strong safety guarantees for cyber-physical systems, but typical techniques for using these tools rely on three assumptions that break down when applying verification techniques to real autonomous systems: 1. CPS verification techniques assume that a symbolic representation of the state of the world is known a priori. For example, formal CPS models of ground robots typically assume that the system knows the positions of all relevant obstacles, at least within some error bound [16].


Explainable AI for a No-Teardown Vehicle Component Cost Estimation: A Top-Down Approach

arXiv.org Artificial Intelligence

The broader ambition of this article is to popularize an approach for the fair distribution of the quantity of a system's output to its subsystems, while allowing for underlying complex subsystem level interactions. Particularly, we present a data-driven approach to vehicle price modeling and its component price estimation by leveraging a combination of concepts from machine learning and game theory. We show an alternative to common teardown methodologies and surveying approaches for component and vehicle price estimation at the manufacturer's suggested retail price (MSRP) level that has the advantage of bypassing the uncertainties involved in 1) the gathering of teardown data, 2) the need to perform expensive and biased surveying, and 3) the need to perform retail price equivalent (RPE) or indirect cost multiplier (ICM) adjustments to mark up direct manufacturing costs to MSRP. This novel exercise not only provides accurate pricing of the technologies at the customer level, but also shows the, a priori known, large gaps in pricing strategies between manufacturers, vehicle sizes, classes, market segments, and other factors. There is also clear synergism or interaction between the price of certain technologies and other specifications present in the same vehicle. Those (unsurprising) results are indication that old methods of manufacturer-level component costing, aggregation, and the application of a flat and rigid RPE or ICM adjustment factor should be carefully examined. The findings are based on an extensive database, developed by Argonne National Laboratory, that includes more than 64,000 vehicles covering MY1990 to MY2020 over hundreds of vehicle specs.


Certifying Strategyproof Auction Networks

arXiv.org Artificial Intelligence

Optimal auctions maximize a seller's expected revenue subject to individual rationality and strategyproofness for the buyers. Myerson's seminal work in 1981 settled the case of auctioning a single item; however, subsequent decades of work have yielded little progress moving beyond a single item, leaving the design of revenue-maximizing auctions as a central open problem in the field of mechanism design. A recent thread of work in "differentiable economics" has used tools from modern deep learning to instead learn good mechanisms. We focus on the RegretNet architecture, which can represent auctions with arbitrary numbers of items and participants; it is trained to be empirically strategyproof, but the property is never exactly verified leaving potential loopholes for market participants to exploit. We propose ways to explicitly verify strategyproofness under a particular valuation profile using techniques from the neural network verification literature. Doing so requires making several modifications to the RegretNet architecture in order to represent it exactly in an integer program. We train our network and produce certificates in several settings, including settings for which the optimal strategyproof mechanism is not known.