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Decentralized Cooperative Planning for Automated Vehicles with Continuous Monte Carlo Tree Search

arXiv.org Artificial Intelligence

Urban traffic scenarios often require a high degree of cooperation between traffic participants to ensure safety and efficiency. Observing the behavior of others, humans infer whether or not others are cooperating. This work aims to extend the capabilities of automated vehicles, enabling them to cooperate implicitly in heterogeneous environments. Continuous actions allow for arbitrary trajectories and hence are applicable to a much wider class of problems than existing cooperative approaches with discrete action spaces. Based on cooperative modeling of other agents, Monte Carlo Tree Search (MCTS) in conjunction with Decoupled-UCT evaluates the action-values of each agent in a cooperative and decentralized way, respecting the interdependence of actions among traffic participants. The extension to continuous action spaces is addressed by incorporating novel MCTS-specific enhancements for efficient search space exploration. The proposed algorithm is evaluated under different scenarios, showing that the algorithm is able to achieve effective cooperative planning and generate solutions egocentric planning fails to identify.


Performance Metrics (Error Measures) in Machine Learning Regression, Forecasting and Prognostics: Properties and Typology

arXiv.org Machine Learning

Performance metrics (error measures) are vital components of the evaluation frameworks in various fields. The intention of this study was to overview of a variety of performance metrics and approaches to their classification. The main goal of the study was to develop a typology that will help to improve our knowledge and understanding of metrics and facilitate their selection in machine learning regression, forecasting and prognostics. Based on the analysis of the structure of numerous performance metrics, we propose a framework of metrics which includes four (4) categories: primary metrics, extended metrics, composite metrics, and hybrid sets of metrics. The paper identified three (3) key components (dimensions) that determine the structure and properties of primary metrics: method of determining point distance, method of normalization, method of aggregation of point distances over a data set.


Elliptical Distributions-Based Weights-Determining Method for OWA Operators

arXiv.org Artificial Intelligence

The ordered weighted averaging (OWA) operators play a crucial role in aggregating multiple criteria evaluations into an overall assessment supporting the decision makers' choice. One key point steps is to determine the associated weights. In this paper, we first briefly review some main methods for determining the weights by using distribution functions. Then we propose a new approach for determining OWA weights by using the RIM quantifier. Motivated by the idea of normal distribution-based method to determine the OWA weights, we develop a method based on elliptical distributions for determining the OWA weights, and some of its desirable properties have been investigated.


Why are Sequence-to-Sequence Models So Dull? Understanding the Low-Diversity Problem of Chatbots

arXiv.org Artificial Intelligence

Diversity is a long-studied topic in information retrieval that usually refers to the requirement that retrieved results should be non-repetitive and cover different aspects. In a conversational setting, an additional dimension of diversity matters: an engaging response generation system should be able to output responses that are diverse and interesting. Sequence-to-sequence (Seq2Seq) models have been shown to be very effective for response generation. However, dialogue responses generated by Seq2Seq models tend to have low diversity. In this paper, we review known sources and existing approaches to this low-diversity problem. We also identify a source of low diversity that has been little studied so far, namely model over-confidence. We sketch several directions for tackling model over-confidence and, hence, the low-diversity problem, including confidence penalties and label smoothing.


Neural Architecture Search: A Survey

arXiv.org Machine Learning

Deep Learning has enabled remarkable progress over the last years on a variety of tasks, such as image recognition, speech recognition, and machine translation. One crucial aspect for this progress are novel neural architectures. Currently employed architectures have mostly been developed manually by human experts, which is a time-consuming and error-prone process. Because of this, there is growing interest in automated neural architecture search methods. We provide an overview of existing work in this field of research and categorize them according to three dimensions: search space, search strategy, and performance estimation strategy.


Utilizing Character and Word Embeddings for Text Normalization with Sequence-to-Sequence Models

arXiv.org Machine Learning

Text normalization is an important enabling technology for several NLP tasks. Recently, neural-network-based approaches have outperformed well-established models in this task. However, in languages other than English, there has been little exploration in this direction. Both the scarcity of annotated data and the complexity of the language increase the difficulty of the problem. To address these challenges, we use a sequence-to-sequence model with character-based attention, which in addition to its self-learned character embeddings, uses word embeddings pre-trained with an approach that also models subword information. This provides the neural model with access to more linguistic information especially suitable for text normalization, without large parallel corpora. We show that providing the model with word-level features bridges the gap for the neural network approach to achieve a state-of-the-art F1 score on a standard Arabic language correction shared task dataset.


Recognizing human facial expressions with machine learning

#artificialintelligence

Machine learning systems can be trained to recognize emotional expressions from images of human faces, with a high degree of accuracy in many cases. Image by Tsukiko Kiyomidzu However, implementation can be a complex and difficult task. The technology is at a relatively early stage. High quality datasets can be hard to find. And there are various pitfalls to avoid when designing new systems. This article provides an introduction to the field known as Facial Expression Recognition (FER).


Big data and AI: How cutting-edge technology can change the healthcare industry

#artificialintelligence

Google, Amazon, and IBM joined forces with Microsoft, Salesforce, and Oracle to pledge to speed up the progress of health data standards and interoperability. This historical collaboration between the biggest artificial intelligence (AI) players will lead to enormous advances in AI, which itself will lead to earlier diagnoses and better treatments at lower cost, according to GlobalData. The companies claim that this project will lead to better outcomes, higher patient satisfaction, and lower costs--a so-called'Triple Aim'. GlobalData CVMD Director Valentina Gburcik comments, "This big new alliance's pledge will have a very positive impact on healthcare as it will become easier to share medical data among hospitals. "Both physicians and patients will have easier access to information, which will lead to faster diagnosis and treatment.


A Review of Inference Algorithms for Hybrid Bayesian Networks

Journal of Artificial Intelligence Research

Hybrid Bayesian networks have received an increasing attention during the last years. The difference with respect to standard Bayesian networks is that they can host discrete and continuous variables simultaneously, which extends the applicability of the Bayesian network framework in general. However, this extra feature also comes at a cost: inference in these types of models is computationally more challenging and the underlying models and updating procedures may not even support closed-form solutions. In this paper we provide an overview of the main trends and principled approaches for performing inference in hybrid Bayesian networks. The methods covered in the paper are organized and discussed according to their methodological basis. We consider how the methods have been extended and adapted to also include (hybrid) dynamic Bayesian networks, and we end with an overview of established software systems supporting inference in these types of models.


How to meet patient demand for AI in health care

#artificialintelligence

The past 10 years have given us some truly innovative technology; now, healthcare providers are beginning to figure out the best ways to use it. They would do well to follow other industries by listening to consumers – in this case, patients – to determine the best way to incorporate this technology into their workflows. In this guest post, Vinay Seth Mohta, a managing director at an artificial intelligence engineering services firm, offers three patient-focused AI applications that might be a good place for healthcare executives to start. Accenture's "2018 Consumer Survey on Digital Health" found that three-quarters of the patients surveyed use technology to manage their own health. In addition, patients said they were eager to incorporate a new kind of technology into their health care: artificial intelligence.