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Air-Writing Translater: A Novel Unsupervised Domain Adaptation Method for Inertia-Trajectory Translation of In-air Handwriting

arXiv.org Artificial Intelligence

JOURNAL OF XXX CLASS FILES, VOL. 1, NO. 1, JUNE 2019 1 Air-Writing Translater: A Novel Unsupervised Domain Adaptation Method for Inertia-Trajectory Translation of In-air Handwriting Songbin Xu, Y ang Xue, Xin Zhang, Lianwen Jin As a new way of human-computer interaction, inertial sensor based in-air handwriting can provide a natural and unconstrained interaction to express more complex and richer information in 3D space. However, most of the existing in-air handwriting work is mainly focused on handwritten character recognition, which makes these work suffer from poor readability of inertial signal and lack of labeled samples. T o address these two problems, we use unsupervised domain adaptation method to reconstruct the trajectory of inertial signal and generate inertial samples using online handwritten trajectories. In this paper, we propose an Air-Writing Translater model to learn the bidirectional translation between trajectory domain and inertial domain in the absence of paired inertial and trajectory samples. Through semantic-level adversarial training and latent classification loss, the proposed model learns to extract domain-invariant content between inertial signal and trajectory, while preserving semantic consistency during the translation across the two domains. We carefully design the architecture, so that the proposed framework can accept inputs of arbitrary length and translate between different sampling rates. We also conduct experiments on two public datasets: 6DMG (in-air handwriting dataset) and CT (handwritten trajectory dataset), the results on the two datasets demonstrate that the proposed network successes in both Inertia-to Trajectory and Trajectory-to-Inertia translation tasks. I NTRODUCTION I NAIR handwriting refers to a novel way of human-computer interaction (HCI), which freely writes meaningful characters in 3D space and then converts them into user-to-computer commands. Compared with general motion gestures, in-air handwriting is more complicated and provides more abundant expressions. As modern MEMS(Micro-Electro- Mechanical System) inertial sensors become smaller and more energy efficient, they have been universally employed in portable and wearable devices such as smartphones and wristbands. Unlike optical devices, inertial sensors do not suffer from illumination interference and obstruction. Therefore, inertial sensor based in-air handwriting has widely attracted researchers' attention [1]-[4]. Most of the existing work is mainly focused on in-air handwriting recognition (IAHR) [5]-[8]. But in the research of IAHR, there are usually two problems. Firstly, the inertial signal is full of abstractness and lack of readability, because it is a series of temporal sequences representing motion shifting, as illustrated in Fig.1(a).


Thompson Sampling for Contextual Bandit Problems with Auxiliary Safety Constraints

arXiv.org Artificial Intelligence

Recent advances in contextual bandit optimization and reinforcement learning have garnered interest in applying these methods to real-world sequential decision making problems. Real-world applications frequently have constraints with respect to a currently deployed policy. Many of the existing constraint-aware algorithms consider problems with a single objective (the reward) and a constraint on the reward with respect to a baseline policy. However, many important applications involve multiple competing objectives and auxiliary constraints. In this paper, we propose a novel Thompson sampling algorithm for multi-outcome contextual bandit problems with auxiliary constraints. We empirically evaluate our algorithm on a synthetic problem. Lastly, we apply our method to a real world video transcoding problem and provide a practical way for navigating the trade-off between safety and performance using Bayesian optimization.


Explicit Explore-Exploit Algorithms in Continuous State Spaces

arXiv.org Artificial Intelligence

We present a new model-based algorithm for reinforcement learning (RL) which consists of explicit exploration and exploitation phases, and is applicable in large or infinite state spaces. The algorithm maintains a set of dynamics models consistent with current experience and explores by finding policies which induce high disagreement between their state predictions. It then exploits using the refined set of models or experience gathered during exploration. We show that under realizability and optimal planning assumptions, our algorithm provably finds a near-optimal policy with a number of samples that is polynomial in a structural complexity measure which we show to be low in several natural settings. We then give a practical approximation using neural networks and demonstrate its performance and sample efficiency in practice.


SHACL Constraints with Inference Rules

arXiv.org Artificial Intelligence

The Shapes Constraint Language (SHACL) has been recently introduced as a W3C recommendation to define constraints that can be validated against RDF graphs. Interactions of SHACL with other Semantic Web technologies, such as ontologies or reasoners, is a matter of ongoing research. In this paper we study the interaction of a subset of SHACL with inference rules expressed in datalog. On the one hand, SHACL constraints can be used to define a "schema" for graph datasets. On the other hand, inference rules can lead to the discovery of new facts that do not match the original schema. Given a set of SHACL constraints and a set of datalog rules, we present a method to detect which constraints could be violated by the application of the inference rules on some graph instance of the schema, and update the original schema, i.e, the set of SHACL constraints, in order to capture the new facts that can be inferred. We provide theoretical and experimental results of the various components of our approach.


A Perceived Environment Design using a Multi-Modal Variational Autoencoder for learning Active-Sensing

arXiv.org Artificial Intelligence

I. INTRODUCTION Active sensing (AS) is one of the most fundamental problems and challenges in mobile robotics which seeks to maximize the efficiency of an estimation task by actively controlling the sensing parameters [1]. AS can be divided into two sub-tasks: the identification of a point of interest (PoI) to achieve (e.g. In teams of heterogeneous robots that employ different sensory modalities, AS is of particular interest as it can be used to resolve observation ambiguities. Friston [2] states that minimizing free energy is equivalent to maximizing model evidence, which is equivalent to minimizing the complexity of accurate explanations for observed outcomes. Following this principle, if one could directly obtain an estimation of free energy through the current observation, a controller for sensing parameters can be learned that minimizes free energy.


What Gets Echoed? Understanding the "Pointers" in Explanations of Persuasive Arguments

arXiv.org Artificial Intelligence

They can take many forms, ranging from everyday explanations for questions such as why one likes Star Wars, to sophisticated formalization in the philosophy of science (Salmon, 2006), to simply highlighting features in recent work on interpretable machine learning (Ribeiro et al., 2016). Although everyday explanations are mostly encoded in natural language, natural language explanations remain understudied in NLP, partly due to a lack of appropriate datasets and problem formulations. To address these challenges, we leverage /r/ChangeMyView, a community dedicated to sharing counterarguments to controversial views on Reddit, to build a sizable dataset of naturally-occurring explanations. Specifically, in /r/ChangeMyView, an original poster (OP) first delineates the rationales for a (controversial) opinion (e.g., in Table 1, "most hit music artists today are bad musicians"). Members of /r/ChangeMyVieware invited to provide counterarguments. If a counterargument changes the OP's view, the OP awards a to indicate the change and is required to explain why the counterargument is persuasive . In this work, we refer to what is being explained, including both the original post and the persuasive comment, as the explanandum.


Reasoning Over Paths via Knowledge Base Completion

arXiv.org Artificial Intelligence

This is crucial for the use of large Knowledge bases in many downstream applications. However explaining the predictions given by a KBC algorithm is quite important for several real world use cases. For example in rec-ommender systems, a knowledge graph of users, items and their interactions are used to recommend an item to a user based on the users interactions on several items. The ability to explain and reason on the decision is of critical importance to add knowledge to recommender systems. Similarly in a knowledge graph consisting human biological data such as genes, drugs, symptoms and diseases, it is crucial to know which gene and symptoms were involved in predicting a drug for a disease. This requires automatic extraction and ranking of multi-hop paths between a given source and a target entity from a knowledge graph. Previous work has focused on using path information in knowledge graphs for KBC known as path-based inference (Lao et al., 2011; Gardner et al., 2014; Neelakantan et al., 2015; Das et al., 2017b), in which a model is trained to predict missing links between a given pair of entities taking as input several paths that existed between them. Paths are ranked according to a scoring method and used as features to train the model. Embedding-based inference models (Bordes et al., 2013; Lin et al., 2015; Nickel et al., 2011; Socher et al., 2013; Trouillon et al., 2016) for KBC learn entity and relation embeddings by solving an optimization problem that maximises the plausibility of known facts in the knowledge graph.


Explaining black box decisions by Shapley cohort refinement

arXiv.org Artificial Intelligence

Black box prediction models used in statistics, machine learning and artificial intelligence have been able to make increasingly accurate predictions, but it remains hard to understand those predictions. See for example, ˇ Strumbelj and Kononenko (2010, 2014), Ribeiro et al. (2016), Sundararajan and Najmi (2019) and the book of Molnar (2018). Part of understanding predictions is understanding which variables are important. A variable could be important because changing it makes a causal difference, or because changing it makes a large change to our predictions or because leaving it out of a model reduces that model's prediction accuracy (Jiang and Owen, 2003). Importance by one of these criteria need not imply importance by another, though additional assumptions may allow a causal implication to be made from one of the other measures (Pearl, 2009; Zhao and Hastie, 2019). We could be interested in variables that are important overall or in variables that explain one single prediction, such as why a given person was or was not approved for a loan, or why a given patient was or was not placed in an intensive care unit.


Research and application of time series algorithms in centralized purchasing data

arXiv.org Artificial Intelligence

Based on the online transaction data of COSCO group's centralized procurement platform, this paper studies the clustering method of time series type data. The different methods of similarity calculation, different clustering methods with different K values are analysed, and the best clustering method suitable for centralized purchasing data is determined. The company list under the corresponding cluster is obtained. The time series motif discovery algorithm is used to model the centroid of each cluster. Through ARIMA method, we also made 12 periods of prediction for the centroid of each category. This paper constructs a matrix of "Customer Lifecycle Theory - Five Elements of Marketing ", and puts forward corresponding marketing suggestions for customers at different life cycle stages.


Generalized Speedy Q-learning

arXiv.org Artificial Intelligence

In this paper, we derive a generalization of the Speedy Q-learning (SQL) algorithm that was proposed in the Reinforcement Learning (RL) literature to handle slow convergence of Watkins' Q-learning. In most RL algorithms such as Q-learning, the Bellman equation and the Bellman operator play an important role. It is possible to generalize the Bellman operator using the technique of successive relaxation. We use the generalized Bellman operator to derive a simple and efficient family of algorithms called Generalized Speedy Q-learning (GSQL-w) and analyze its finite time performance. We show that GSQL-w has an improved finite time performance bound compared to SQL for the case when the relaxation parameter w is greater than 1. This improvement is a consequence of the contraction factor of the generalized Bellman operator being less than that of the standard Bellman operator. Numerical experiments are provided to demonstrate the empirical performance of the GSQL-w algorithm.