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Deception through Half-Truths
Estornell, Andrew, Das, Sanmay, Vorobeychik, Yevgeniy
Deception is a fundamental issue across a diverse array of settings, from cybersecurity, where decoys (e.g., honeypots) are an important tool, to politics that can feature politically motivated "leaks" and fake news about candidates.Typical considerations of deception view it as providing false information.However, just as important but less frequently studied is a more tacit form where information is strategically hidden or leaked.We consider the problem of how much an adversary can affect a principal's decision by "half-truths", that is, by masking or hiding bits of information, when the principal is oblivious to the presence of the adversary. The principal's problem can be modeled as one of predicting future states of variables in a dynamic Bayes network, and we show that, while theoretically the principal's decisions can be made arbitrarily bad, the optimal attack is NP-hard to approximate, even under strong assumptions favoring the attacker. However, we also describe an important special case where the dependency of future states on past states is additive, in which we can efficiently compute an approximately optimal attack. Moreover, in networks with a linear transition function we can solve the problem optimally in polynomial time.
Partial-Order, Partially-Seen Observations of Fluents or Actions for Plan Recognition as Planning
Nelson, Jennifer M., Cardona-Rivera, Rogelio E.
This work aims to make plan recognition as planning more ready for real-world scenarios by adapting previous compilations to work with partial-order, half-seen observations of both fluents and actions. We first redefine what observations can be and what it means to satisfy each kind. We then provide a compilation from plan recognition problem to classical planning problem, similar to original work by Ramirez and Geffner, but accommodating these more complex observation types. This compilation can be adapted towards other planning-based plan recognition techniques. Lastly we evaluate this method against an "ignore complexity" strategy that uses the original method by Ramirez and Geffner. Our experimental results suggest that, while slower, our method is equally or more accurate than baseline methods; our technique sometimes significantly reduces the size of the solution to the plan recognition problem, i.e, the size of the optimal goal set. We discuss these findings in the context of plan recognition problem difficulty and present an avenue for future work.
Motion Reasoning for Goal-Based Imitation Learning
Huang, De-An, Chao, Yu-Wei, Paxton, Chris, Deng, Xinke, Fei-Fei, Li, Niebles, Juan Carlos, Garg, Animesh, Fox, Dieter
De-An Huang 1, 2, Y u-Wei Chao, 2, Chris Paxton, 2, Xinke Deng 2, 3, Li Fei-Fei 1, Juan Carlos Niebles 1, Animesh Garg 2, 4, Dieter Fox 2, 5 Abstract -- We address goal-based imitation learning, where the aim is to output the symbolic goal from a third-person video demonstration. This enables the robot to plan for execution and reproduce the same goal in a completely different environment. The key challenge is that the goal of a video demonstration is often ambiguous at the level of semantic actions. The human demonstrators might unintentionally achieve certain subgoals in the demonstrations with their actions. Our main contribution is to propose a motion reasoning framework that combines task and motion planning to disambiguate the true intention of the demonstrator in the video demonstration. This allows us to robustly recognize the goals that cannot be disambiguated by previous action-based approaches. We evaluate our approach by collecting a dataset of 96 video demonstrations in a mockup kitchen environment. We show that our motion reasoning plays an important role in recognizing the actual goal of the demonstrator and improves the success rate by over 20%. We further show that by using the automatically inferred goal from the video demonstration, our robot is able to reproduce the same task in a real kitchen environment. I NTRODUCTION We are interested in allowing robots to learn new tasks from video demonstrations. Recently, there has been rapid progress in imitation learning [1-4], which even enables learning a new task from a single demonstration of the task [5-7]. By leveraging meta-learning [8], the robot learns to follow the actions in the demonstration.
HDDL -- A Language to Describe Hierarchical Planning Problems
Höller, D., Behnke, G., Bercher, P., Biundo, S., Fiorino, H., Pellier, D., Alford, R.
The research in hierarchical planning has made considerable progress in the last few years. Many recent systems do not rely on hand-tailored advice anymore to find solutions, but are supposed to be domain-independent systems that come with sophisticated solving techniques. In principle, this development would make the comparison between systems easier (because the domains are not tailored to a single system anymore) and -- much more important -- also the integration into other systems, because the modeling process is less tedious (due to the lack of advice) and there is no (or less) commitment to a certain planning system the model is created for. However, these advantages are destroyed by the lack of a common input language and feature set supported by the different systems. In this paper, we propose an extension to PDDL, the description language used in non-hierarchical planning, to the needs of hierarchical planning systems. We restrict our language to a basic feature set shared by many recent systems, give an extension of PDDL's EBNF syntax definition, and discuss our extensions with respect to several planner-specific input languages from related work.
SAVEHR: Self Attention Vector Representations for EHR based Personalized Chronic Disease Onset Prediction and Interpretability
Mallya, Sunil, Overhage, Marc, Bodapati, Sravan, Srivastava, Navneet, Genc, Sahika
Chronic disease progression is emerging as an important area of investment for healthcare providers. As the quantity and richness of available clinical data continue to increase along with advances in machine learning, there is great potential to advance our approaches to caring for patients. An ideal approach to this problem should generate good performance on at least three axes namely, a) perform across many clinical conditions without requiring deep clinical expertise or extensive data scientist effort, b) generalization across populations, and c) be explainable (model interpretability). We present SAVEHR, a self-attention based architecture on heterogeneous structured EHR data that achieves $>$ 0.51 AUC-PR and $>$ 0.87 AUC-ROC gains on predicting the onset of four clinical conditions (CHF, Kidney Failure, Diabetes and COPD) 15-months in advance, and transfers with high performance onto a new population. We demonstrate that SAVEHR model performs superior to ten baselines on all three axes stated formerly.
IRIS: Implicit Reinforcement without Interaction at Scale for Learning Control from Offline Robot Manipulation Data
Mandlekar, Ajay, Ramos, Fabio, Boots, Byron, Fei-Fei, Li, Garg, Animesh, Fox, Dieter
Learning from offline task demonstrations is a problem of great interest in robotics. For simple short-horizon manipulation tasks with modest variation in task instances, offline learning from a small set of demonstrations can produce controllers that successfully solve the task. However, leveraging a fixed batch of data can be problematic for larger datasets and longer-horizon tasks with greater variations. The data can exhibit substantial diversity and consist of suboptimal solution approaches. In this paper, we propose Implicit Reinforcement without Interaction at Scale (IRIS), a novel framework for learning from large-scale demonstration datasets. IRIS factorizes the control problem into a goal-conditioned low-level controller that imitates short demonstration sequences and a high-level goal selection mechanism that sets goals for the low-level and selectively combines parts of suboptimal solutions leading to more successful task completions. We evaluate IRIS across three datasets, including the RoboTurk Cans dataset collected by humans via crowdsourcing, and show that performant policies can be learned from purely offline learning. Additional results and videos at https://stanfordvl.github.io/iris/ .
A Graph Auto-Encoder for Haplotype Assembly and Viral Quasispecies Reconstruction
Reconstructing components of a genomic mixture from data obtained by means of DNA sequencing is a challenging problem encountered in a variety of applications including single individual haplotyping and studies of viral communities. High-throughput DNA sequencing platforms oversample mixture components to provide massive amounts of reads whose relative positions can be determined by mapping the reads to a known reference genome; assembly of the components, however, requires discovery of the reads' origin -- an NP-hard problem that the existing methods struggle to solve with the required level of accuracy. In this paper, we present a learning framework based on a graph auto-encoder designed to exploit structural properties of sequencing data. The algorithm is a neural network which essentially trains to ignore sequencing errors and infers the posteriori probabilities of the origin of sequencing reads. Mixture components are then reconstructed by finding consensus of the reads determined to originate from the same genomic component. Results on realistic synthetic as well as experimental data demonstrate that the proposed framework reliably assembles haplotypes and reconstructs viral communities, often significantly outperforming state-of-the-art techniques.
MIDAS: Microcluster-Based Detector of Anomalies in Edge Streams
Bhatia, Siddharth, Hooi, Bryan, Yoon, Minji, Shin, Kijung, Faloutsos, Christos
Given a stream of graph edges from a dynamic graph, how can we assign anomaly scores to edges in an online manner, for the purpose of detecting unusual behavior, using constant time and memory? Existing approaches aim to detect individually surprising edges. In this work, we propose MIDAS, which focuses on detecting microcluster anomalies, or suddenly arriving groups of suspiciously similar edges, such as lockstep behavior, including denial of service attacks in network traffic data. MIDAS has the following properties: (a) it detects microcluster anomalies while providing theoretical guarantees about its false positive probability; (b) it is online, thus processing each edge in constant time and constant memory, and also processes the data 108-505 times faster than state-of-the-art approaches; (c) it provides 46%-52% higher accuracy (in terms of AUC) than state-of-the-art approaches.
Minecraft Earth is live, so get tapping – TechCrunch
Microsoft's big experiment in real-world augmented reality gaming, Minecraft Earth, is live now for players in North America, the U.K., and a number of other areas. The pocket-size AR game lets you collect blocks and critters wherever you go, undertake little adventures with friends, and of course build sweet castles. I played an early version of Minecraft Earth earlier this year, and found it entertaining and the AR aspect surprisingly seamless. The gameplay many were first introduced to in Pokemon GO is adapted here in a more creative and collaborative way. You still walk around your neighborhood, rendered in this case charmingly like a Minecraft world, and tap little icons that pop up around your character. These may be blocks you can use to build, animals you can collect, or events like combat encounters that you can do alone or with friends for rewards.
Minecraft Earth is live, so get tapping – TechCrunch
Microsoft's big experiment in real-world augmented reality gaming, Minecraft Earth, is live now for players in North America, the U.K., and a number of other areas. The pocket-size AR game lets you collect blocks and critters wherever you go, undertake little adventures with friends, and of course build sweet castles. I played an early version of Minecraft Earth earlier this year, and found it entertaining and the AR aspect surprisingly seamless. The gameplay many were first introduced to in Pokemon GO is adapted here in a more creative and collaborative way. You still walk around your neighborhood, rendered in this case charmingly like a Minecraft world, and tap little icons that pop up around your character. These may be blocks you can use to build, animals you can collect, or events like combat encounters that you can do alone or with friends for rewards.