在过去的二十年中,已经采用了过采样来克服从不平衡数据集中学习的挑战。文献中提出了许多解决这一挑战的方法。另一方面,过采样是一个问题。也就是说,在解决现实世界问题时,经过虚拟数据训练的模型可能会出色地失败。过采样方法的根本困难是,鉴于现实生活中的人群,合成的样本可能并不真正属于少数群体。结果,在假装代表少数群体的同时,在这些样本上训练分类器可能会导致在现实世界中使用该模型时的预测。我们在本文中分析了大量的过采样方法,并根据隐藏了许多多数示例,设计了一种新的过采样评估系统,并将其与通过过采样过程产生的示例进行了比较。根据我们的评估系统,我们根据它们错误生成的示例进行比较对所有这些方法进行了排名。我们使用70多种超采样方法和三种不平衡现实世界数据集的实验表明,所有研究的过采样方法都会生成最有可能是多数人的少数样本。给定数据和方法,我们认为以目前的形式和方法对从类不平衡数据学习不可靠,应在现实世界中避免。
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经典的双赢有一个关键的缺陷,因为它不能为各方提供适当的获胜,因为每一方认为他们是赢家。实际上,一方可能比另一方赢得更多。该策略不仅限于单一产品或谈判;它可以应用于生活中的各种情况。我们提出了一种衡量本文双赢的新颖方式。该方法采用模糊逻辑来创建一个数学模型,援助谈判者量化其获胜百分比。该模型采用现实生活谈判的考验,如伊朗铀浓缩谈判,伊拉克 - 约旦石油交易和铁矿石谈判(2005-2009)。呈现的模型在实践中表明是一种有用的工具,并且可以容易地广泛地在其他域中使用。
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基于全面的生物识别是一个广泛的研究区域。然而,仅使用部分可见的面,例如在遮盖的人的情况下,是一个具有挑战性的任务。在这项工作中使用深卷积神经网络(CNN)来提取来自遮盖者面部图像的特征。我们发现,第六和第七完全连接的层,FC6和FC7分别在VGG19网络的结构中提供了鲁棒特征,其中这两层包含4096个功能。这项工作的主要目标是测试基于深度学习的自动化计算机系统的能力,不仅要识别人,还要对眼睛微笑等性别,年龄和面部表达的认可。我们的实验结果表明,我们为所有任务获得了高精度。最佳记录的准确度值高达99.95%,用于识别人员,99.9%,年龄识别的99.9%,面部表情(眼睛微笑)认可为80.9%。
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With the development of deep representation learning, the domain of reinforcement learning (RL) has become a powerful learning framework now capable of learning complex policies in high dimensional environments. This review summarises deep reinforcement learning (DRL) algorithms and provides a taxonomy of automated driving tasks where (D)RL methods have been employed, while addressing key computational challenges in real world deployment of autonomous driving agents. It also delineates adjacent domains such as behavior cloning, imitation learning, inverse reinforcement learning that are related but are not classical RL algorithms. The role of simulators in training agents, methods to validate, test and robustify existing solutions in RL are discussed.
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While the capabilities of autonomous systems have been steadily improving in recent years, these systems still struggle to rapidly explore previously unknown environments without the aid of GPS-assisted navigation. The DARPA Subterranean (SubT) Challenge aimed to fast track the development of autonomous exploration systems by evaluating their performance in real-world underground search-and-rescue scenarios. Subterranean environments present a plethora of challenges for robotic systems, such as limited communications, complex topology, visually-degraded sensing, and harsh terrain. The presented solution enables long-term autonomy with minimal human supervision by combining a powerful and independent single-agent autonomy stack, with higher level mission management operating over a flexible mesh network. The autonomy suite deployed on quadruped and wheeled robots was fully independent, freeing the human supervision to loosely supervise the mission and make high-impact strategic decisions. We also discuss lessons learned from fielding our system at the SubT Final Event, relating to vehicle versatility, system adaptability, and re-configurable communications.
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This paper presents our solutions for the MediaEval 2022 task on DisasterMM. The task is composed of two subtasks, namely (i) Relevance Classification of Twitter Posts (RCTP), and (ii) Location Extraction from Twitter Texts (LETT). The RCTP subtask aims at differentiating flood-related and non-relevant social posts while LETT is a Named Entity Recognition (NER) task and aims at the extraction of location information from the text. For RCTP, we proposed four different solutions based on BERT, RoBERTa, Distil BERT, and ALBERT obtaining an F1-score of 0.7934, 0.7970, 0.7613, and 0.7924, respectively. For LETT, we used three models namely BERT, RoBERTa, and Distil BERTA obtaining an F1-score of 0.6256, 0.6744, and 0.6723, respectively.
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In recent years, social media has been widely explored as a potential source of communication and information in disasters and emergency situations. Several interesting works and case studies of disaster analytics exploring different aspects of natural disasters have been already conducted. Along with the great potential, disaster analytics comes with several challenges mainly due to the nature of social media content. In this paper, we explore one such challenge and propose a text classification framework to deal with Twitter noisy data. More specifically, we employed several transformers both individually and in combination, so as to differentiate between relevant and non-relevant Twitter posts, achieving the highest F1-score of 0.87.
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Three main points: 1. Data Science (DS) will be increasingly important to heliophysics; 2. Methods of heliophysics science discovery will continually evolve, requiring the use of learning technologies [e.g., machine learning (ML)] that are applied rigorously and that are capable of supporting discovery; and 3. To grow with the pace of data, technology, and workforce changes, heliophysics requires a new approach to the representation of knowledge.
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Image classification with small datasets has been an active research area in the recent past. However, as research in this scope is still in its infancy, two key ingredients are missing for ensuring reliable and truthful progress: a systematic and extensive overview of the state of the art, and a common benchmark to allow for objective comparisons between published methods. This article addresses both issues. First, we systematically organize and connect past studies to consolidate a community that is currently fragmented and scattered. Second, we propose a common benchmark that allows for an objective comparison of approaches. It consists of five datasets spanning various domains (e.g., natural images, medical imagery, satellite data) and data types (RGB, grayscale, multispectral). We use this benchmark to re-evaluate the standard cross-entropy baseline and ten existing methods published between 2017 and 2021 at renowned venues. Surprisingly, we find that thorough hyper-parameter tuning on held-out validation data results in a highly competitive baseline and highlights a stunted growth of performance over the years. Indeed, only a single specialized method dating back to 2019 clearly wins our benchmark and outperforms the baseline classifier.
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Dataset scaling, also known as normalization, is an essential preprocessing step in a machine learning pipeline. It is aimed at adjusting attributes scales in a way that they all vary within the same range. This transformation is known to improve the performance of classification models, but there are several scaling techniques to choose from, and this choice is not generally done carefully. In this paper, we execute a broad experiment comparing the impact of 5 scaling techniques on the performances of 20 classification algorithms among monolithic and ensemble models, applying them to 82 publicly available datasets with varying imbalance ratios. Results show that the choice of scaling technique matters for classification performance, and the performance difference between the best and the worst scaling technique is relevant and statistically significant in most cases. They also indicate that choosing an inadequate technique can be more detrimental to classification performance than not scaling the data at all. We also show how the performance variation of an ensemble model, considering different scaling techniques, tends to be dictated by that of its base model. Finally, we discuss the relationship between a model's sensitivity to the choice of scaling technique and its performance and provide insights into its applicability on different model deployment scenarios. Full results and source code for the experiments in this paper are available in a GitHub repository.\footnote{https://github.com/amorimlb/scaling\_matters}
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