Agents
Conflict-Based Search for Explainable Multi-Agent Path Finding
Kottinger, Justin, Almagor, Shaull, Lahijanian, Morteza
In the Multi-Agent Path Finding (MAPF) problem, the goal is to find non-colliding paths for agents in an environment, such that each agent reaches its goal from its initial location. In safety-critical applications, a human supervisor may want to verify that the plan is indeed collision-free. To this end, a recent work introduces a notion of explainability for MAPF based on a visualization of the plan as a short sequence of images representing time segments, where in each time segment the trajectories of the agents are disjoint. Then, the explainable MAPF problem asks for a set of non-colliding paths that admits a short-enough explanation. Explainable MAPF adds a new difficulty to MAPF, in that it is NP-hard with respect to the size of the environment, and not just the number of agents. Thus, traditional MAPF algorithms are not equipped to directly handle explainable-MAPF. In this work, we adapt Conflict Based Search (CBS), a well-studied algorithm for MAPF, to handle explainable MAPF. We show how to add explainability constraints on top of the standard CBS tree and its underlying A* search. We examine the usefulness of this approach and, in particular, the tradeoff between planning time and explainability.
Byzantine-Robust Federated Linear Bandits
Jadbabaie, Ali, Li, Haochuan, Qian, Jian, Tian, Yi
In this paper, we study a linear bandit optimization problem in a federated setting where a large collection of distributed agents collaboratively learn a common linear bandit model. Standard federated learning algorithms applied to this setting are vulnerable to Byzantine attacks on even a small fraction of agents. We propose a novel algorithm with a robust aggregation oracle that utilizes the geometric median. We prove that our proposed algorithm is robust to Byzantine attacks on fewer than half of agents and achieves a sublinear $\tilde{\mathcal{O}}({T^{3/4}})$ regret with $\mathcal{O}(\sqrt{T})$ steps of communication in $T$ steps. Moreover, we make our algorithm differentially private via a tree-based mechanism. Finally, if the level of corruption is known to be small, we show that using the geometric median of mean oracle for robust aggregation further improves the regret bound.
Knowledge-based Entity Prediction for Improved Machine Perception in Autonomous Systems
For example, consider the case where the perception module detects a pedestrian (PCV) on the road. It does not, however, recognize that the pedestrian is jaywalking. Even if no jaywalking events have been seen while training the CV perception module, representing knowledge of this event – i.e. (Pedestrian, participatesIn, Jaywalking) – in the scene KG could provide a new insight or cue for handling this edge-case with KEP (i.e.
Robust and Efficient Aggregation for Distributed Learning
Vlaski, Stefan, Schroth, Christian, Muma, Michael, Zoubir, Abdelhak M.
Distributed learning paradigms, such as federated and decentralized learning, allow for the coordination of models across a collection of agents, and without the need to exchange raw data. Instead, agents compute model updates locally based on their available data, and subsequently share the update model with a parameter server or their peers. This is followed by an aggregation step, which traditionally takes the form of a (weighted) average. Distributed learning schemes based on averaging are known to be susceptible to outliers. A single malicious agent is able to drive an averaging-based distributed learning algorithm to an arbitrarily poor model. This has motivated the development of robust aggregation schemes, which are based on variations of the median and trimmed mean. While such procedures ensure robustness to outliers and malicious behavior, they come at the cost of significantly reduced sample efficiency. This means that current robust aggregation schemes require significantly higher agent participation rates to achieve a given level of performance than their mean-based counterparts in non-contaminated settings. In this work we remedy this drawback by developing statistically efficient and robust aggregation schemes for distributed learning.
On the Indecisiveness of Kelly-Strategyproof Social Choice Functions
Brandt, Felix, Bullinger, Martin, Lederer, Patrick
Social choice functions (SCFs) map the preferences of a group of agents over some set of alternatives to a non-empty subset of alternatives. The Gibbard-Satterthwaite theorem has shown that only extremely restrictive SCFs are strategyproof when there are more than two alternatives. For set-valued SCFs, or so-called social choice correspondences, the situation is less clear. There are miscellaneous -- mostly negative -- results using a variety of strategyproofness notions and additional requirements. The simple and intuitive notion of Kelly-strategyproofness has turned out to be particularly compelling because it is weak enough to still allow for positive results. For example, the Pareto rule is strategyproof even when preferences are weak, and a number of attractive SCFs (such as the top cycle, the uncovered set, and the essential set) are strategyproof for strict preferences. In this paper, we show that, for weak preferences, only indecisive SCFs can satisfy strategyproofness. In particular, (i) every strategyproof rank-based SCF violates Pareto-optimality, (ii) every strategyproof support-based SCF (which generalize Fishburn's C2 SCFs) that satisfies Pareto-optimality returns at least one most preferred alternative of every voter, and (iii) every strategyproof non-imposing SCF returns the Condorcet loser in at least one profile. We also discuss the consequences of these results for randomized social choice.
Predicting Decisions in Language Based Persuasion Games
Apel, Reut (Technion) | Erev, Ido (Technion) | Reichart, Roi (Technion, Israel Institute of Technology) | Tennenholtz, Moshe
Sender-receiver interactions, and specifically persuasion games, are widely researched in economic modeling and artificial intelligence, and serve as a solid foundation for powerful applications. However, in the classic persuasion games setting, the messages sent from the expert to the decision-maker are abstract or well-structured application-specific signals rather than natural (human) language messages, although natural language is a very common communication signal in real-world persuasion setups. This paper addresses the use of natural language in persuasion games, exploring its impact on the decisions made by the players and aiming to construct effective models for the prediction of these decisions. For this purpose, we conduct an online repeated interaction experiment. At each trial of the interaction, an informed expert aims to sell an uninformed decision-maker a vacation in a hotel, by sending her a review that describes the hotel. While the expert is exposed to several scored reviews, the decision-maker observes only the single review sent by the expert, and her payoff in case she chooses to take the hotel is a random draw from the review score distribution available to the expert only. The expert’s payoff, in turn, depends on the number of times the decision-maker chooses the hotel. We also compare the behavioral patterns in this experiment to the equivalent patterns in similar experiments where the communication is based on the numerical values of the reviews rather than the reviews’ text, and observe substantial differences which can be explained through an equilibrium analysis of the game. We consider a number of modeling approaches for our verbal communication setup, differing from each other in the model type (deep neural network (DNN) vs. linear classifier), the type of features used by the model (textual, behavioral or both) and the source of the textual features (DNN-based vs. hand-crafted). Our results demonstrate that given a prefix of the interaction sequence, our models can predict the future decisions of the decision-maker, particularly when a sequential modeling approach and hand-crafted textual features are applied. Further analysis of the hand-crafted textual features allows us to make initial observations about the aspects of text that drive decision making in our setup.
ServiceNow BrandVoice: The Mind-Blowing Possibilities Of Relentless AI
Here's a fun game: Name one person you know who enjoys sitting on hold, waiting for a customer service agent to resolve an issue or answer a question. AI can transform your customer service experience--if you implement it with care. But what if I were to say that AI can enable a world where you'll never again be held hostage on hold, wincing every time the smooth jazz version of Duran Duran's "Hungry Like the Wolf" repeats ad nauseum? It's true--customer service and support is a prime candidate for using AI to improve the customer experience and enable the team to scale. As the person responsible for operationalizing AI within ServiceNow's customer support experience, I seek out stages in the customer journey where AI can automate processes.
Oscars 2022: Who Got More Winners Right, AI or the Movie Experts?
Every year for the last six years, Unanimous AI has been more accurate than movie critics at predicting Oscar winners. It uses swarm intelligence the power of interactive group decisions enhanced by AI – to transform regular people into expert decision-makers. How did it do this year? Unanimous AI took a group of regular movie fans and created a'hive mind' in which their combined choices are smarter than those of any individual member. "We can take a group of people and turn them into a super organism," founder Louis Rosenberg told IoT World Today's sister publication AI Business.
FedLGA: Towards System-Heterogeneity of Federated Learning via Local Gradient Approximation
Li, Xingyu, Qu, Zhe, Tang, Bo, Lu, Zhuo
Federated Learning (FL) is a decentralized machine learning architecture, which leverages a large number of remote devices to learn a joint model with distributed training data. However, the system-heterogeneity is one major challenge in a FL network to achieve robust distributed learning performance, which comes from two aspects: i) device-heterogeneity due to the diverse computational capacity among devices; ii) data-heterogeneity due to the non-identically distributed data across the network. Prior studies addressing the heterogeneous FL issue, e.g., FedProx, lack formalization and it remains an open problem. This work first formalizes the system-heterogeneous FL problem and proposes a new algorithm, called FedLGA, to address this problem by bridging the divergence of local model updates via gradient approximation. To achieve this, FedLGA provides an alternated Hessian estimation method, which only requires extra linear complexity on the aggregator. Theoretically, we show that with a device-heterogeneous ratio $\rho$, FedLGA achieves convergence rates on non-i.i.d. distributed FL training data for the non-convex optimization problems with $\mathcal{O} \left( \frac{(1+\rho)}{\sqrt{ENT}} + \frac{1}{T} \right)$ and $\mathcal{O} \left( \frac{(1+\rho)\sqrt{E}}{\sqrt{TK}} + \frac{1}{T} \right)$ for full and partial device participation respectively, where $E$ is the number of local learning epoch, $T$ is the number of total communication round, $N$ is the total device number and $K$ is the number of selected device in one communication round under partially participation scheme. The results of comprehensive experiments on multiple datasets show that FedLGA outperforms current FL methods against the system-heterogeneity.
Overview of Embodied Artificial Intelligence
Recent research trends in Artificial Intelligence, Machine Learning, and Computer Vision have led to a growing research space called Embodied AI. Facebook AI Research (FAIR) and Intel Labs has been spearheading new projects in the space of Embodied AI. "Embodied" is defined as "giving a tangible or visible form to an idea." Simply put, "Embodied AI" means "AI for virtual robots." More specifically, Embodied AI is the field for solving AI problems for virtual robots that can move, see, speak, and interact in the virtual world and with other virtual robots -- these simulated robot solutions are then transferred to real world robots. Linda Smith proposed the "embodiment hypothesis" in 2005 as the idea that intelligence emerges in the interaction of an agent with an environment and as a result of sensorimotor activity. They argue that starting as a baby grounded in a physical, social, and linguistic world is crucial to the development of the flexible and inventive intelligence that characterizes humankind. Furthermore, the Embodiment Thesis states that many features of cognition are embodied in that they are deeply dependent upon characteristics of the physical body of an agent, such that the agent's beyond-the-brain body plays a significant causal role, or a physically constitutive role, in that agent's cognitive processing.