Agents
The Interplay Between Artificial Intelligence and Uncertainty
In this first article, we highlight how intelligence and rationality are tightly coupled with the uncertainty present in the world. We also discuss how uncertainty plays a critical role in designing beneficial general-purpose artificial intelligence (AI), as described by the work of Stuart Russel and Peter Norvig on Modern AI [1][2]. Human intelligence, both social and individual, is what has been driving advances achieved by the human civilization. Having access to even greater intelligence in the form of machine artificial intelligence (AI) can potentially lead to even further advances, and will help us solve major problems such as eliminating poverty and disease, solving open scientific and mathematical problems, and offering personal assistance targeting billions of people worldwide. This is subject of course to the finite resources of land and raw material available on earth.
Interactive Reinforcement Learning for Feature Selection with Decision Tree in the Loop
Fan, Wei, Liu, Kunpeng, Liu, Hao, Ge, Yong, Xiong, Hui, Fu, Yanjie
We study the problem of balancing effectiveness and efficiency in automated feature selection. After exploring many feature selection methods, we observe a computational dilemma: 1) traditional feature selection is mostly efficient, but difficult to identify the best subset; 2) the emerging reinforced feature selection automatically navigates to the best subset, but is usually inefficient. Can we bridge the gap between effectiveness and efficiency under automation? Motivated by this dilemma, we aim to develop a novel feature space navigation method. In our preliminary work, we leveraged interactive reinforcement learning to accelerate feature selection by external trainer-agent interaction. In this journal version, we propose a novel interactive and closed-loop architecture to simultaneously model interactive reinforcement learning (IRL) and decision tree feedback (DTF). Specifically, IRL is to create an interactive feature selection loop and DTF is to feed structured feature knowledge back to the loop. First, the tree-structured feature hierarchy from decision tree is leveraged to improve state representation. In particular, we represent the selected feature subset as an undirected graph of feature-feature correlations and a directed tree of decision features. We propose a new embedding method capable of empowering graph convolutional network to jointly learn state representation from both the graph and the tree. Second, the tree-structured feature hierarchy is exploited to develop a new reward scheme. In particular, we personalize reward assignment of agents based on decision tree feature importance. In addition, observing agents' actions can be feedback, we devise another reward scheme, to weigh and assign reward based on the feature selected frequency ratio in historical action records. Finally, we present extensive experiments on real-world datasets to show the improved performance.
Correcting Experience Replay for Multi-Agent Communication
Ahilan, Sanjeevan, Dayan, Peter
We consider the problem of learning to communicate using multi-agent reinforcement learning (MARL). A common approach is to learn off-policy, using data sampled from a replay buffer. However, messages received in the past may not accurately reflect the current communication policy of each agent, and this complicates learning. We therefore introduce a 'communication correction' which accounts for the non-stationarity of observed communication induced by multi-agent learning. It works by relabelling the received message to make it likely under the communicator's current policy, and thus be a better reflection of the receiver's current environment. To account for cases in which agents are both senders and receivers, we introduce an ordered relabelling scheme. Our correction is computationally efficient and can be integrated with a range of off-policy algorithms. It substantially improves the ability of communicating MARL systems to learn across a variety of cooperative and competitive tasks.
Reinforcement Learning of Simple Indirect Mechanisms
Brero, Gianluca, Eden, Alon, Gerstgrasser, Matthias, Parkes, David C., Rheingans-Yoo, Duncan
Over the last fifty years, a large body of research in microeconomics has introduced many different mechanisms for resource allocation. Despite the wide variety of available options, "simple" mechanisms such as posted price and serial dictatorship are often preferred for practical applications, including housing allocation [Abdulkadiroğlu and Sönmez, 1998], online procurement [Badanidiyuru et al., 2012], or allocation of medical appointments [Klaus and Nichifor, 2019]. There has been considerable interest in formalizing different notions of simplicity. Li [2017] identifies mechanisms that are particularly simple from a strategic perspective, introducing the concept of obviously strategyproof mechanisms; under obviously strategyproof mechanisms, it is obvious that an agent cannot profit by trying to game the system, as even the worst possible final outcome from behaving truthfully is at least as good as the best possible outcome from any other strategy. Pycia and Troyan [2019] introduce the still stronger concept of strongly obviously strategyproof (SOSP) mechanisms, and show that this class can essentially be identified with sequential price mechanisms, where agents are visited in turn and offered a choice from a menu of options (which may or may not include transfers). SOSP mechanisms are ones in which an agent is not even required to consider her future (truthful) actions to understand that the mechanism is obviously strategyproof.
Public Announcement Logic in HOL
Reiche, Sebastian, Benzmüller, Christoph
A shallow semantical embedding for public announcement logic with relativized common knowledge is presented. This embedding enables the first-time automation of this logic with off-the-shelf theorem provers for classical higher-order logic. It is demonstrated (i) how meta-theoretical studies can be automated this way, and (ii) how non-trivial reasoning in the target logic (public announcement logic), required e.g. to obtain a convincing encoding and automation of the wise men puzzle, can be realized. Key to the presented semantical embedding -- in contrast, e.g., to related work on the semantical embedding of normal modal logics -- is that evaluation domains are modeled explicitly and treated as additional parameter in the encodings of the constituents of the embedded target logic, while they were previously implicitly shared between meta logic and target logic.
AI improves customer experience, call center efficiency
Artificial intelligence serves a number of purposes in contact centers. It can automate routine processes, provide live chat in the form of virtual agents or chatbots to address customer queries, help deliver personalized experiences and provide predictive analytics, among other things. Each of these AI functions helps enhance both the employee and customer experience, and many CX leaders are taking a closer look at how it can help in their companies. The driving force behind this movement is the increase in contact center interaction volume as COVID-19 shows no end in sight, moving customers from physical to virtual buying patterns and requiring help from live customer service agents. CX leaders have reported many changes in their contact centers, including the need for more agents to support customer demand over both the phone and digital channels, and replacing in-person experiences with virtual ones -- driving even more traffic to the contact center.
Student-Initiated Action Advising via Advice Novelty
Ilhan, Ercument, Perez-Liebana, Diego
Action advising is a knowledge exchange mechanism between peers, namely student and teacher, that can help tackle exploration and sample inefficiency problems in deep reinforcement learning. Due to the practical limitations in peer-to-peer communication and the negative implications of over-advising, the peer responsible for initiating these interactions needs to do so only when it's most adequate to exchange advice. Most recently, student-initiated techniques that utilise state novelty and uncertainty estimations have obtained promising results. However, these estimations have several weaknesses, such as having no information regarding the characteristics of convergence and being subject to delays that occur in the presence of experience replay dynamics. We propose a student-initiated action advising algorithm that alleviates these shortcomings. Specifically, we employ Random Network Distillation (RND) to measure the novelty of an advice, for the student to determine whether to proceed with the request; furthermore, we perform RND updates only for the advised states to ensure that the student's convergence will not prevent it from utilising the teacher's knowledge at any stage of learning. Experiments in GridWorld and simplified versions of five Atari games show that our approach can perform on par with the state-of-the-art and demonstrate significant advantages in the scenarios where the existing methods are prone to fail.
Multi-agent Social Reinforcement Learning Improves Generalization
Ndousse, Kamal, Eck, Douglas, Levine, Sergey, Jaques, Natasha
Social learning is a key component of human and animal intelligence. By taking cues from the behavior of experts in their environment, social learners can acquire sophisticated behavior and rapidly adapt to new circumstances. This paper investigates whether independent reinforcement learning (RL) agents in a multi-agent environment can use social learning to improve their performance using cues from other agents. We find that in most circumstances, vanilla model-free RL agents do not use social learning, even in environments in which individual exploration is expensive. We analyze the reasons for this deficiency, and show that by introducing a model-based auxiliary loss we are able to train agents to lever-age cues from experts to solve hard exploration tasks. The generalized social learning policy learned by these agents allows them to not only outperform the experts with which they trained, but also achieve better zero-shot transfer performance than solo learners when deployed to novel environments with experts. In contrast, agents that have not learned to rely on social learning generalize poorly and do not succeed in the transfer task. Further,we find that by mixing multi-agent and solo training, we can obtain agents that use social learning to out-perform agents trained alone, even when experts are not avail-able. This demonstrates that social learning has helped improve agents' representation of the task itself. Our results indicate that social learning can enable RL agents to not only improve performance on the task at hand, but improve generalization to novel environments.
Mediating Artificial Intelligence Developments through Negative and Positive Incentives
Han, The Anh, Pereira, Luis Moniz, Lenaerts, Tom, Santos, Francisco C.
The field of Artificial Intelligence (AI) is going through a period of great expectations, introducing a certain level of anxiety in research, business and also policy. This anxiety is further energised by an AI race narrative that makes people believe they might be missing out. Whether real or not, a belief in this narrative may be detrimental as some stake-holders will feel obliged to cut corners on safety precautions, or ignore societal consequences just to "win". Starting from a baseline model that describes a broad class of technology races where winners draw a significant benefit compared to others (such as AI advances, patent race, pharmaceutical technologies), we investigate here how positive (rewards) and negative (punishments) incentives may beneficially influence the outcomes. We uncover conditions in which punishment is either capable of reducing the development speed of unsafe participants or has the capacity to reduce innovation through over-regulation. Alternatively, we show that, in several scenarios, rewarding those that follow safety measures may increase the development speed while ensuring safe choices. Moreover, in {the latter} regimes, rewards do not suffer from the issue of over-regulation as is the case for punishment. Overall, our findings provide valuable insights into the nature and kinds of regulatory actions most suitable to improve safety compliance in the contexts of both smooth and sudden technological shifts.
Entropy Regularization for Mean Field Games with Learning
Guo, Xin, Xu, Renyuan, Zariphopoulou, Thaleia
Entropy regularization has been extensively adopted to improve the efficiency, the stability, and the convergence of algorithms in reinforcement learning. This paper analyzes both quantitatively and qualitatively the impact of entropy regularization for Mean Field Game (MFG) with learning in a finite time horizon. Our study provides a theoretical justification that entropy regularization yields time-dependent policies and, furthermore, helps stabilizing and accelerating convergence to the game equilibrium. In addition, this study leads to a policy-gradient algorithm for exploration in MFG. Under this algorithm, agents are able to learn the optimal exploration scheduling, with stable and fast convergence to the game equilibrium.