操作网络通常依靠机器学习模型来进行许多任务,包括检测异常,推断应用程序性能和预测需求。然而,不幸的是,模型精度会因概念漂移而降低,从而,由于从软件升级到季节性到用户行为的变化,功能和目标预测之间的关系会发生变化。因此,缓解概念漂移是操作机器学习模型的重要组成部分,尽管它很重要,但在网络或一般的回归模型的背景下,概念漂移并未得到广泛的探索。因此,对于当前依赖机器学习模型的许多常见网络管理任务,如何检测或减轻它并不是一件好事。不幸的是,正如我们所展示的那样,通过使用新可用的数据经常重新培训模型可以充分缓解概念漂移,甚至可以进一步降低模型的准确性。在本文中,我们表征了美国主要大都市地区的大型蜂窝网络中的概念漂移。我们发现,概念漂移发生在许多重要的关键性能指标(KPI)上,独立于模型,训练集大小和时间间隔,因此需要采用实用方法来检测,解释和减轻它。为此,我们开发了特征(叶)的局部误差近似。叶检测到漂移;解释最有助于漂移的功能和时间间隔;并使用遗忘和过度采样来减轻漂移。我们使用超过四年的蜂窝KPI数据来评估叶子与行业标准的缓解方法。在美国,我们对主要的细胞提供商进行的初步测试表明,LEAF在各种KPI和模型上都是有效的。叶子始终优于周期性,并触发重新培训,同时还要降低昂贵的重新经营操作。
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近年来,随着传感器和智能设备的广泛传播,物联网(IoT)系统的数据生成速度已大大增加。在物联网系统中,必须经常处理,转换和分析大量数据,以实现各种物联网服务和功能。机器学习(ML)方法已显示出其物联网数据分析的能力。但是,将ML模型应用于物联网数据分析任务仍然面临许多困难和挑战,特别是有效的模型选择,设计/调整和更新,这给经验丰富的数据科学家带来了巨大的需求。此外,物联网数据的动态性质可能引入概念漂移问题,从而导致模型性能降解。为了减少人类的努力,自动化机器学习(AUTOML)已成为一个流行的领域,旨在自动选择,构建,调整和更新机器学习模型,以在指定任务上实现最佳性能。在本文中,我们对Automl区域中模型选择,调整和更新过程中的现有方法进行了审查,以识别和总结将ML算法应用于IoT数据分析的每个步骤的最佳解决方案。为了证明我们的发现并帮助工业用户和研究人员更好地实施汽车方法,在这项工作中提出了将汽车应用于IoT异常检测问题的案例研究。最后,我们讨论并分类了该领域的挑战和研究方向。
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Concept drift primarily refers to an online supervised learning scenario when the relation between the input data and the target variable changes over time. Assuming a general knowledge of supervised learning in this paper we characterize adaptive learning process, categorize existing strategies for handling concept drift, overview the most representative, distinct and popular techniques and algorithms, discuss evaluation methodology of adaptive algorithms, and present a set of illustrative applications. The survey covers the different facets of concept drift in an integrated way to reflect on the existing scattered state-of-the-art. Thus, it aims at providing a comprehensive introduction to the concept drift adaptation for researchers, industry analysts and practitioners.
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Concept drift describes unforeseeable changes in the underlying distribution of streaming data over time. Concept drift research involves the development of methodologies and techniques for drift detection, understanding and adaptation. Data analysis has revealed that machine learning in a concept drift environment will result in poor learning results if the drift is not addressed. To help researchers identify which research topics are significant and how to apply related techniques in data analysis tasks, it is necessary that a high quality, instructive review of current research developments and trends in the concept drift field is conducted. In addition, due to the rapid development of concept drift in recent years, the methodologies of learning under concept drift have become noticeably systematic, unveiling a framework which has not been mentioned in literature. This paper reviews over 130 high quality publications in concept drift related research areas, analyzes up-to-date developments in methodologies and techniques, and establishes a framework of learning under concept drift including three main components: concept drift detection, concept drift understanding, and concept drift adaptation. This paper lists and discusses 10 popular synthetic datasets and 14 publicly available benchmark datasets used for evaluating the performance of learning algorithms aiming at handling concept drift. Also, concept drift related research directions are covered and discussed. By providing state-of-the-art knowledge, this survey will directly support researchers in their understanding of research developments in the field of learning under concept drift.
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本文调查了股票回购,特别是分享回购公告。它解决了如何识别此类公告,股票回购的超额回报以及股票回购公告后的回报的预测。我们说明了两种NLP方法,用于自动检测股票回购公告。即使有少量的培训数据,我们也可以达到高达90%的准确性。该论文利用这些NLP方法生成一个由57,155个股票回购公告组成的大数据集。通过分析该数据集,本论文的目的是表明大多数宣布回购的公司的大多数公司都表现不佳。但是,少数公司的表现极大地超过了MSCI世界。当查看所有公司的平均值时,这种重要的表现过高会导致净收益。如果根据公司的规模调整了基准指数,则平均表现过高,并且大多数表现不佳。但是,发现宣布股票回购的公司至少占其市值的1%,即使使用调整后的基准,也平均交付了显着的表现。还发现,在危机时期宣布股票回购的公司比整个市场更好。此外,生成的数据集用于训练72个机器学习模型。通过此,它能够找到许多可以达到高达77%并产生大量超额回报的策略。可以在六个不同的时间范围内改善各种性能指标,并确定明显的表现。这是通过训练多个模型的不同任务和时间范围以及结合这些不同模型的方法来实现的,从而通过融合弱学习者来产生重大改进,以创造一个强大的学习者。
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如今,人工智能(AI)已成为临床和远程医疗保健应用程序的基本组成部分,但是最佳性能的AI系统通常太复杂了,无法自我解释。可解释的AI(XAI)技术被定义为揭示系统的预测和决策背后的推理,并且在处理敏感和个人健康数据时,它们变得更加至关重要。值得注意的是,XAI并未在不同的研究领域和数据类型中引起相同的关注,尤其是在医疗保健领域。特别是,许多临床和远程健康应用程序分别基于表格和时间序列数据,而XAI并未在这些数据类型上进行分析,而计算机视觉和自然语言处理(NLP)是参考应用程序。为了提供最适合医疗领域表格和时间序列数据的XAI方法的概述,本文提供了过去5年中文献的审查,说明了生成的解释的类型以及为评估其相关性所提供的努力和质量。具体而言,我们确定临床验证,一致性评估,客观和标准化质量评估以及以人为本的质量评估作为确保最终用户有效解释的关键特征。最后,我们强调了该领域的主要研究挑战以及现有XAI方法的局限性。
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Platelet products are both expensive and have very short shelf lives. As usage rates for platelets are highly variable, the effective management of platelet demand and supply is very important yet challenging. The primary goal of this paper is to present an efficient forecasting model for platelet demand at Canadian Blood Services (CBS). To accomplish this goal, four different demand forecasting methods, ARIMA (Auto Regressive Moving Average), Prophet, lasso regression (least absolute shrinkage and selection operator) and LSTM (Long Short-Term Memory) networks are utilized and evaluated. We use a large clinical dataset for a centralized blood distribution centre for four hospitals in Hamilton, Ontario, spanning from 2010 to 2018 and consisting of daily platelet transfusions along with information such as the product specifications, the recipients' characteristics, and the recipients' laboratory test results. This study is the first to utilize different methods from statistical time series models to data-driven regression and a machine learning technique for platelet transfusion using clinical predictors and with different amounts of data. We find that the multivariate approaches have the highest accuracy in general, however, if sufficient data are available, a simpler time series approach such as ARIMA appears to be sufficient. We also comment on the approach to choose clinical indicators (inputs) for the multivariate models.
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非侵入性负载监控(NILM)是将总功率消耗分为单个子组件的任务。多年来,已经合并了信号处理和机器学习算法以实现这一目标。关于最先进的方法,进行了许多出版物和广泛的研究工作,以涉及最先进的方法。科学界最初使用机器学习工具的尼尔姆问题制定和描述的最初兴趣已经转变为更实用的尼尔姆。如今,我们正处于成熟的尼尔姆时期,在现实生活中的应用程序方案中尝试使用尼尔姆。因此,算法的复杂性,可转移性,可靠性,实用性和普遍的信任度是主要的关注问题。这篇评论缩小了早期未成熟的尼尔姆时代与成熟的差距。特别是,本文仅对住宅电器的尼尔姆方法提供了全面的文献综述。本文分析,总结并介绍了大量最近发表的学术文章的结果。此外,本文讨论了这些方法的亮点,并介绍了研究人员应考虑的研究困境,以应用尼尔姆方法。最后,我们表明需要将传统分类模型转移到一个实用且值得信赖的框架中。
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The literature on machine learning in the context of data streams is vast and growing. However, many of the defining assumptions regarding data-stream learning tasks are too strong to hold in practice, or are even contradictory such that they cannot be met in the contexts of supervised learning. Algorithms are chosen and designed based on criteria which are often not clearly stated, for problem settings not clearly defined, tested in unrealistic settings, and/or in isolation from related approaches in the wider literature. This puts into question the potential for real-world impact of many approaches conceived in such contexts, and risks propagating a misguided research focus. We propose to tackle these issues by reformulating the fundamental definitions and settings of supervised data-stream learning with regard to contemporary considerations of concept drift and temporal dependence; and we take a fresh look at what constitutes a supervised data-stream learning task, and a reconsideration of algorithms that may be applied to tackle such tasks. Through and in reflection of this formulation and overview, helped by an informal survey of industrial players dealing with real-world data streams, we provide recommendations. Our main emphasis is that learning from data streams does not impose a single-pass or online-learning approach, or any particular learning regime; and any constraints on memory and time are not specific to streaming. Meanwhile, there exist established techniques for dealing with temporal dependence and concept drift, in other areas of the literature. For the data streams community, we thus encourage a shift in research focus, from dealing with often-artificial constraints and assumptions on the learning mode, to issues such as robustness, privacy, and interpretability which are increasingly relevant to learning in data streams in academic and industrial settings.
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人工智能(AI)和机器学习(ML)在网络安全挑战中的应用已在行业和学术界的吸引力,部分原因是对关键系统(例如云基础架构和政府机构)的广泛恶意软件攻击。入侵检测系统(IDS)使用某些形式的AI,由于能够以高预测准确性处理大量数据,因此获得了广泛的采用。这些系统托管在组织网络安全操作中心(CSOC)中,作为一种防御工具,可监视和检测恶意网络流,否则会影响机密性,完整性和可用性(CIA)。 CSOC分析师依靠这些系统来决定检测到的威胁。但是,使用深度学习(DL)技术设计的IDS通常被视为黑匣子模型,并且没有为其预测提供理由。这为CSOC分析师造成了障碍,因为他们无法根据模型的预测改善决策。解决此问题的一种解决方案是设计可解释的ID(X-IDS)。这项调查回顾了可解释的AI(XAI)的最先进的ID,目前的挑战,并讨论了这些挑战如何涉及X-ID的设计。特别是,我们全面讨论了黑匣子和白盒方法。我们还在这些方法之间的性能和产生解释的能力方面提出了权衡。此外,我们提出了一种通用体系结构,该建筑认为人类在循环中,该架构可以用作设计X-ID时的指南。研究建议是从三个关键观点提出的:需要定义ID的解释性,需要为各种利益相关者量身定制的解释以及设计指标来评估解释的需求。
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预测可帮助企业分配资源并实现目标。在LinkedIn,产品所有者使用预测来设定业务目标,跟踪前景和监视健康。工程师使用预测有效地提供硬件。开发一种预测解决方案来满足这些需求,需要对各种时间序列进行准确,可解释的预测,并以次数至季度的频率。我们提出了Greykite,这是一个用于预测的开源Python库,已在LinkedIn上部署了二十多种用例。它的旗舰算法Silverkite提供了可解释的,快速且高度灵活的单变量预测,可捕获诸如时期增长和季节性,自相关,假期和回归剂等效果。该库通过促进数据探索,模型配置,执行和解释来实现自我服务的准确性和信任。我们的基准结果显示了来自各个域的数据集的现成速度和准确性。在过去的两年中,金融,工程和产品团队的资源计划和分配,目标设置和进度跟踪,异常检测和根本原因分析的资源团队一直信任灰金矿的预测。我们希望灰金矿对具有类似应用的预测从业者有用,这些应用需要准确,可解释的预测,这些预测捕获了与人类活动相关的时间序列共有的复杂动力学。
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Time series anomaly detection has applications in a wide range of research fields and applications, including manufacturing and healthcare. The presence of anomalies can indicate novel or unexpected events, such as production faults, system defects, or heart fluttering, and is therefore of particular interest. The large size and complex patterns of time series have led researchers to develop specialised deep learning models for detecting anomalous patterns. This survey focuses on providing structured and comprehensive state-of-the-art time series anomaly detection models through the use of deep learning. It providing a taxonomy based on the factors that divide anomaly detection models into different categories. Aside from describing the basic anomaly detection technique for each category, the advantages and limitations are also discussed. Furthermore, this study includes examples of deep anomaly detection in time series across various application domains in recent years. It finally summarises open issues in research and challenges faced while adopting deep anomaly detection models.
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Automated Machine Learning (AutoML) has been used successfully in settings where the learning task is assumed to be static. In many real-world scenarios, however, the data distribution will evolve over time, and it is yet to be shown whether AutoML techniques can effectively design online pipelines in dynamic environments. This study aims to automate pipeline design for online learning while continuously adapting to data drift. For this purpose, we design an adaptive Online Automated Machine Learning (OAML) system, searching the complete pipeline configuration space of online learners, including preprocessing algorithms and ensembling techniques. This system combines the inherent adaptation capabilities of online learners with the fast automated pipeline (re)optimization capabilities of AutoML. Focusing on optimization techniques that can adapt to evolving objectives, we evaluate asynchronous genetic programming and asynchronous successive halving to optimize these pipelines continually. We experiment on real and artificial data streams with varying types of concept drift to test the performance and adaptation capabilities of the proposed system. The results confirm the utility of OAML over popular online learning algorithms and underscore the benefits of continuous pipeline redesign in the presence of data drift.
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机器学习(ML)代表了当前和未来信息系统的关键技术,许多域已经利用了ML的功能。但是,网络安全中ML的部署仍处于早期阶段,揭示了研究和实践之间的显着差异。这种差异在当前的最新目的中具有其根本原因,该原因不允许识别ML在网络安全中的作用。除非广泛的受众理解其利弊,否则ML的全部潜力将永远不会释放。本文是对ML在整个网络安全领域中的作用的首次尝试 - 对任何对此主题感兴趣的潜在读者。我们强调了ML在人类驱动的检测方法方面的优势,以及ML在网络安全方面可以解决的其他任务。此外,我们阐明了影响网络安全部署实际ML部署的各种固有问题。最后,我们介绍了各种利益相关者如何为网络安全中ML的未来发展做出贡献,这对于该领域的进一步进步至关重要。我们的贡献补充了两项实际案例研究,这些案例研究描述了ML作为对网络威胁的辩护的工业应用。
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COVID-19的大流行提出了对多个领域决策者的流行预测的重要性,从公共卫生到整个经济。虽然预测流行进展经常被概念化为类似于天气预测,但是它具有一些关键的差异,并且仍然是一项非平凡的任务。疾病的传播受到人类行为,病原体动态,天气和环境条件的多种混杂因素的影响。由于政府公共卫生和资助机构的倡议,捕获以前无法观察到的方面的丰富数据来源的可用性增加了研究的兴趣。这尤其是在“以数据为中心”的解决方案上进行的一系列工作,这些解决方案通过利用非传统数据源以及AI和机器学习的最新创新来增强我们的预测能力的潜力。这项调查研究了各种数据驱动的方法论和实践进步,并介绍了一个概念框架来导航它们。首先,我们列举了与流行病预测相关的大量流行病学数据集和新的数据流,捕获了各种因素,例如有症状的在线调查,零售和商业,流动性,基因组学数据等。接下来,我们将讨论关注最近基于数据驱动的统计和深度学习方法的方法和建模范式,以及将机械模型知识域知识与统计方法的有效性和灵活性相结合的新型混合模型类别。我们还讨论了这些预测系统的现实部署中出现的经验和挑战,包括预测信息。最后,我们重点介绍了整个预测管道中发现的一些挑战和开放问题。
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发现新的超链接使Web爬网程序能够找到尚未索引的新页面。这对于集中的爬行者来说尤为重要,因为他们努力提供对网络的特定部分的全面分析,从而优先考虑发现内容的变化的新页面。在文献中,通常同​​时考虑超链接和内容的变化。但是,还有证据表明这两种改变不一定是相关的。此外,关于预测变化的许多研究假设页面的长期可用,这在实践中是无法实现的。这项工作的目的是提供一种方法来使用短历史有效地检测新的链接。为此,我们使用一周的间隔使用十个爬网的数据集。我们的研究包括三个部分。首先,我们通过分析新的倒出数量的经验属性来获得数据的洞察力。我们观察到这些属性平均随着时间的推移稳定,但在目标页面内外页面的超链接出现的超链接之间存在很大的差异(分别分别是内部和外部倒降)。接下来,我们为三个目标提供统计模型:链路变化率,新链接的存在以及新链接的数量。这些模型包括文献中早些时候使用的功能,以及在这项工作中引入的新功能。我们分析了特征之间的相关性,并调查了他们的信息。一个值得注意的发现是,如果目标页面的历史不可用,那么我们的新功能,代表相关页面的历史,对于目标页面中的新链接最预测。最后,我们将排名方法作为聚焦爬虫的准则,以有效地发现新页面,这对相应的目标实现了出色的性能。
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A well-performing prediction model is vital for a recommendation system suggesting actions for energy-efficient consumer behavior. However, reliable and accurate predictions depend on informative features and a suitable model design to perform well and robustly across different households and appliances. Moreover, customers' unjustifiably high expectations of accurate predictions may discourage them from using the system in the long term. In this paper, we design a three-step forecasting framework to assess predictability, engineering features, and deep learning architectures to forecast 24 hourly load values. First, our predictability analysis provides a tool for expectation management to cushion customers' anticipations. Second, we design several new weather-, time- and appliance-related parameters for the modeling procedure and test their contribution to the model's prediction performance. Third, we examine six deep learning techniques and compare them to tree- and support vector regression benchmarks. We develop a robust and accurate model for the appliance-level load prediction based on four datasets from four different regions (US, UK, Austria, and Canada) with an equal set of appliances. The empirical results show that cyclical encoding of time features and weather indicators alongside a long-short term memory (LSTM) model offer the optimal performance.
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The cyber-physical convergence is opening up new business opportunities for industrial operators. The need for deep integration of the cyber and the physical worlds establishes a rich business agenda towards consolidating new system and network engineering approaches. This revolution would not be possible without the rich and heterogeneous sources of data, as well as the ability of their intelligent exploitation, mainly due to the fact that data will serve as a fundamental resource to promote Industry 4.0. One of the most fruitful research and practice areas emerging from this data-rich, cyber-physical, smart factory environment is the data-driven process monitoring field, which applies machine learning methodologies to enable predictive maintenance applications. In this paper, we examine popular time series forecasting techniques as well as supervised machine learning algorithms in the applied context of Industry 4.0, by transforming and preprocessing the historical industrial dataset of a packing machine's operational state recordings (real data coming from the production line of a manufacturing plant from the food and beverage domain). In our methodology, we use only a single signal concerning the machine's operational status to make our predictions, without considering other operational variables or fault and warning signals, hence its characterization as ``agnostic''. In this respect, the results demonstrate that the adopted methods achieve a quite promising performance on three targeted use cases.
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挖掘数据流姿势存在许多挑战,包括数据的连续和非静止性质,待处理的大量信息和限制计算资源。虽然在文献中提出了一些针对这个问题的监督解决方案,但大多数人都假定访问地面真理(以类标签的形式)是无限的,并且在更新学习系统时可以立即使用此类信息。这远非现实,因为必须考虑获取标签的基本成本。因此,需要解决流方案中实际真相要求的解决方案。在本文中,通过组合来自主动学习和自我标签的信息,提出了一种用于预算的挖水数据流的新框架。我们介绍了几种策略,可以利用智能实例选择和半监督程序,同时考虑到概念漂移的潜在存在。这种混合方法允许有效的探索和利用在现实标记预算中的流数据结构。由于我们的框架工作为包装器,因此它可以应用于不同的学习算法。实验研究,在具有各种类型的概念漂移的多样化现实数据流中进行的实验研究,证明了在处理对类标签的高度限制时拟议的策略的有用性。当一个人不能增加标签或更换低效分类器的预算时,呈现的混合方法尤其可行。我们为我们的战略提供了一套关于适用性领域的建议。
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预测组合在预测社区中蓬勃发展,近年来,已经成为预测研究和活动主流的一部分。现在,由单个(目标)系列产生的多个预测组合通过整合来自不同来源收集的信息,从而提高准确性,从而减轻了识别单个“最佳”预测的风险。组合方案已从没有估计的简单组合方法演变为涉及时间变化的权重,非线性组合,组件之间的相关性和交叉学习的复杂方法。它们包括结合点预测和结合概率预测。本文提供了有关预测组合的广泛文献的最新评论,并参考可用的开源软件实施。我们讨论了各种方法的潜在和局限性,并突出了这些思想如何随着时间的推移而发展。还调查了有关预测组合实用性的一些重要问题。最后,我们以当前的研究差距和未来研究的潜在见解得出结论。
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