我们为基于树的分类器的全球公平验证提供了一种新的方法。鉴于基于树的分类器和一组敏感的特征可能导致歧视,我们的分析综合了足够的公平条件,以表达为一组传统的命题逻辑公式,这些公式很容易被人类专家可以理解。经过验证的公平保证是全局的,因为公式在分类器的所有可能输入上呈现,而不仅仅是一些特定的测试实例。我们的分析被正式证明既声音又完整。公共数据集的实验结果表明,该分析是精确的,可以向人类专家解释,并且足以有效地采用。
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在本文中,我们批评传统上用于评估在对抗环境中部署的机器学习模型的性能的鲁棒性措施。为了减轻稳健性的局限性,我们介绍了一种称为弹性的新措施,我们专注于其验证。特别地,我们讨论如何通过将传统的稳定性验证技术与数据无关的稳定性分析组合来验证弹性,这鉴定了模型不改变其预测的特征空间的子集。然后,我们为决策树和决策树集合介绍了一个正式的数据无关稳定性分析,我们在实验上评估公共数据集,我们利用恢复力验证。我们的结果表明,在实践中,恢复力验证是有用和可行的,产生了对标准和强大决策树模型的更可靠的安全评估。
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In the last years many accurate decision support systems have been constructed as black boxes, that is as systems that hide their internal logic to the user. This lack of explanation constitutes both a practical and an ethical issue. The literature reports many approaches aimed at overcoming this crucial weakness sometimes at the cost of scarifying accuracy for interpretability. The applications in which black box decision systems can be used are various, and each approach is typically developed to provide a solution for a specific problem and, as a consequence, delineating explicitly or implicitly its own definition of interpretability and explanation. The aim of this paper is to provide a classification of the main problems addressed in the literature with respect to the notion of explanation and the type of black box system. Given a problem definition, a black box type, and a desired explanation this survey should help the researcher to find the proposals more useful for his own work. The proposed classification of approaches to open black box models should also be useful for putting the many research open questions in perspective.
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在文献中提出了各种各样的公平度量和可解释的人工智能(XAI)方法,以确定在关键现实环境中使用的机器学习模型中的偏差。但是,仅报告模型的偏差,或使用现有XAI技术生成解释不足以定位并最终减轻偏差源。在这项工作中,我们通过识别对这种行为的根本原因的训练数据的连贯子集来引入Gopher,该系统产生紧凑,可解释和意外模型行为的偏差或意外模型行为。具体而言,我们介绍了因果责任的概念,这些责任通过删除或更新其数据集来解决培训数据的程度可以解决偏差。建立在这一概念上,我们开发了一种有效的方法,用于生成解释模型偏差的顶级模式,该模型偏置利用来自ML社区的技术来实现因果责任,并使用修剪规则来管理模式的大搜索空间。我们的实验评估表明了Gopher在为识别和调试偏置来源产生可解释解释时的有效性。
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最近已经提出了几个查询和分数来解释对ML模型的个人预测。鉴于ML型号的灵活,可靠和易于应用的可解释性方法,我们预见了需要开发声明语言以自然地指定不同的解释性查询。我们以原则的方式通过源于逻辑,称为箔,允许表达许多简单但重要的解释性查询,并且可以作为更具表现力解释性语言的核心来实现这一语言。我们研究箔片查询的两类ML模型的计算复杂性经常被视为容易解释:决策树和OBDD。由于ML模型的可能输入的数量是尺寸的指数,因此箔评估问题的易易性是精细的,但是可以通过限制模型的结构或正在评估的箔片段来实现。我们还以高级声明语言包装的箔片的原型实施,并执行实验,表明可以在实践中使用这种语言。
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背景信息:在过去几年中,机器学习(ML)一直是许多创新的核心。然而,包括在所谓的“安全关键”系统中,例如汽车或航空的系统已经被证明是非常具有挑战性的,因为ML的范式转变为ML带来完全改变传统认证方法。目的:本文旨在阐明与ML为基础的安全关键系统认证有关的挑战,以及文献中提出的解决方案,以解决它们,回答问题的问题如何证明基于机器学习的安全关键系统?'方法:我们开展2015年至2020年至2020年之间发布的研究论文的系统文献综述(SLR),涵盖了与ML系统认证有关的主题。总共确定了217篇论文涵盖了主题,被认为是ML认证的主要支柱:鲁棒性,不确定性,解释性,验证,安全强化学习和直接认证。我们分析了每个子场的主要趋势和问题,并提取了提取的论文的总结。结果:单反结果突出了社区对该主题的热情,以及在数据集和模型类型方面缺乏多样性。它还强调需要进一步发展学术界和行业之间的联系,以加深域名研究。最后,它还说明了必须在上面提到的主要支柱之间建立连接的必要性,这些主要柱主要主要研究。结论:我们强调了目前部署的努力,以实现ML基于ML的软件系统,并讨论了一些未来的研究方向。
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决策树学习是机器学习中广泛使用的方法,在需要简洁明了的模型的应用中受到青睐。传统上,启发式方法用于快速生产具有相当高准确性的模型。然而,一个普遍的批评是,从精度和大小方面,所产生的树可能不一定是数据的最佳表示。近年来,这激发了最佳分类树算法的发展,这些算法与执行一系列本地最佳决策的启发式方法相比,在全球范围内优化决策树。我们遵循这一工作线,并提供了一种基于动态编程和搜索的最佳分类树的新颖算法。我们的算法支持对树的深度和节点数量的约束。我们方法的成功归因于一系列专门技术,这些技术利用了分类树独有的属性。传统上,最佳分类树的算法受到了高运行时的困扰和有限的可伸缩性,但我们在一项详细的实验研究中表明,我们的方法仅使用最先进的时间所需的时间,并且可以处理数十个数据集的数据集在数千个实例中,提供了几个数量级的改进,并特别有助于实现最佳决策树的实现。
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Machine learning (ML) models may be deemed confidential due to their sensitive training data, commercial value, or use in security applications. Increasingly often, confidential ML models are being deployed with publicly accessible query interfaces. ML-as-a-service ("predictive analytics") systems are an example: Some allow users to train models on potentially sensitive data and charge others for access on a pay-per-query basis.The tension between model confidentiality and public access motivates our investigation of model extraction attacks. In such attacks, an adversary with black-box access, but no prior knowledge of an ML model's parameters or training data, aims to duplicate the functionality of (i.e., "steal") the model. Unlike in classical learning theory settings, ML-as-a-service offerings may accept partial feature vectors as inputs and include confidence values with predictions. Given these practices, we show simple, efficient attacks that extract target ML models with near-perfect fidelity for popular model classes including logistic regression, neural networks, and decision trees. We demonstrate these attacks against the online services of BigML and Amazon Machine Learning. We further show that the natural countermeasure of omitting confidence values from model outputs still admits potentially harmful model extraction attacks. Our results highlight the need for careful ML model deployment and new model extraction countermeasures.
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本文考虑了在分解正常形式(DNF,ANDS的DNF,ANDS,相当于判定规则集)或联合正常形式(CNF,ORS)作为分类模型的联合正常形式的学习。为规则简化,将整数程序配制成最佳贸易分类准确性。我们还考虑公平设定,并扩大制定,以包括对两种不同分类措施的明确限制:机会平等和均等的赔率。列生成(CG)用于有效地搜索候选条款(连词或剖钉)的指数数量,而不需要启发式规则挖掘。此方法还会绑定所选规则集之间的间隙和培训数据上的最佳规则集。要处理大型数据集,我们建议使用随机化的近似CG算法。与三个最近提出的替代方案相比,CG算法主导了16个数据集中的8个中的精度简单折衷。当最大限度地提高精度时,CG与为此目的设计的规则学习者具有竞争力,有时发现明显更简单的解决方案,这些解决方案不太准确。与其他公平和可解释的分类器相比,我们的方法能够找到符合较严格的公平概念的规则集,以适度的折衷准确性。
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由于算法预测对人类的影响增加,模型解释性已成为机器学习(ML)的重要问题。解释不仅可以帮助用户了解为什么ML模型做出某些预测,还可以帮助用户了解这些预测如何更改。在本论文中,我们研究了从三个有利位置的ML模型的解释性:算法,用户和教学法,并为解释性问题贡献了一些新颖的解决方案。
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The most widely studied explainable AI (XAI) approaches are unsound. This is the case with well-known model-agnostic explanation approaches, and it is also the case with approaches based on saliency maps. One solution is to consider intrinsic interpretability, which does not exhibit the drawback of unsoundness. Unfortunately, intrinsic interpretability can display unwieldy explanation redundancy. Formal explainability represents the alternative to these non-rigorous approaches, with one example being PI-explanations. Unfortunately, PI-explanations also exhibit important drawbacks, the most visible of which is arguably their size. Recently, it has been observed that the (absolute) rigor of PI-explanations can be traded off for a smaller explanation size, by computing the so-called relevant sets. Given some positive {\delta}, a set S of features is {\delta}-relevant if, when the features in S are fixed, the probability of getting the target class exceeds {\delta}. However, even for very simple classifiers, the complexity of computing relevant sets of features is prohibitive, with the decision problem being NPPP-complete for circuit-based classifiers. In contrast with earlier negative results, this paper investigates practical approaches for computing relevant sets for a number of widely used classifiers that include Decision Trees (DTs), Naive Bayes Classifiers (NBCs), and several families of classifiers obtained from propositional languages. Moreover, the paper shows that, in practice, and for these families of classifiers, relevant sets are easy to compute. Furthermore, the experiments confirm that succinct sets of relevant features can be obtained for the families of classifiers considered.
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机器学习技术的不断增长的复杂性在实践中越来越多地使用,因此需要解释这些模型的预测和决策,通常用作黑盒。可解释的AI方法要么是基于数值的特征,旨在量化每个功能在预测或符号中提供某些形式的符号解释(例如反事实)的贡献。本文提出了一种名为asteryx的通用不可知论方法,允许同时生成符号解释和基于分数的解释。我们的方法是声明性的,它基于在等效符号表示中进行解释的模型的编码,后者用于生成特定两种类型的符号解释,这些解释是足够的原因和反事实。然后,我们将反映解释和特征W.R.T功能的相关性与某些属性相关联。我们的实验结果表明,拟议方法的可行性及其在提供符号和基于得分的解释方面的有效性。
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在许多机器学习应用中已经显示了歧视,该应用程序要求在与道德相关的领域(例如面部识别,医学诊断和刑事判决)中部署之前进行足够的公平测试。现有的公平测试方法主要设计用于识别个人歧视,即对个人的歧视。然而,作为另一种广泛的歧视类型,对群体歧视(大多数隐藏)的测试却少得多。为了解决差距,在这项工作中,我们提出了测试,一种可解释的测试方法,它系统地识别和措施隐藏了一个神经网络的隐藏(我们称为“微妙”群体歧视},该神经网络的特征是敏感特征的条件。一个神经网络,TestsgDFirst自动生成可解释的规则集,该规则集将输入空间分为两组,以暴露模型的组歧视。鉴于,Testsgdalso提供了基于对输入空间进行采样的估计组公平得分,以衡量确定的SIXTEL组歧视程度,这可以确保准确地达到错误的限制。我们评估了在包括结构化数据和文本数据在内的流行数据集中训练的测试多个神经网络模型。实验结果表明,测试有效地有效地识别和测量了如此微妙的群体歧视,以至于该测试效率以前从未透露过。矿石,我们表明,测试的测试结果指南生成新样品的测试结果,以通过可忽略不计的准确性下降来减轻这种歧视。
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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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如今机器学习(ML)技术在许多社交敏感的系统中广泛采用,因此需要仔细研究这些系统所采取的决策的公平性。已经提出了许多方法来解决,并确保没有针对个人或特定群体的偏见,这可能来自偏置训练数据集或算法设计。在这方面,我们提出了一种称为eifffel的公平强化方法:通过翻转叶片来强制森林中的公平,该叶片剥夺了基于树木的或基于叶片的后处理策略来重新制作给定森林的选定决策树的叶子。实验结果表明,我们的方法实现了用户定义的群体公平程度,而不会失去大量的准确性。
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Machine Learning (ML) software has been widely adopted in modern society, with reported fairness implications for minority groups based on race, sex, age, etc. Many recent works have proposed methods to measure and mitigate algorithmic bias in ML models. The existing approaches focus on single classifier-based ML models. However, real-world ML models are often composed of multiple independent or dependent learners in an ensemble (e.g., Random Forest), where the fairness composes in a non-trivial way. How does fairness compose in ensembles? What are the fairness impacts of the learners on the ultimate fairness of the ensemble? Can fair learners result in an unfair ensemble? Furthermore, studies have shown that hyperparameters influence the fairness of ML models. Ensemble hyperparameters are more complex since they affect how learners are combined in different categories of ensembles. Understanding the impact of ensemble hyperparameters on fairness will help programmers design fair ensembles. Today, we do not understand these fully for different ensemble algorithms. In this paper, we comprehensively study popular real-world ensembles: bagging, boosting, stacking and voting. We have developed a benchmark of 168 ensemble models collected from Kaggle on four popular fairness datasets. We use existing fairness metrics to understand the composition of fairness. Our results show that ensembles can be designed to be fairer without using mitigation techniques. We also identify the interplay between fairness composition and data characteristics to guide fair ensemble design. Finally, our benchmark can be leveraged for further research on fair ensembles. To the best of our knowledge, this is one of the first and largest studies on fairness composition in ensembles yet presented in the literature.
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This volume contains revised versions of the papers selected for the third volume of the Online Handbook of Argumentation for AI (OHAAI). Previously, formal theories of argument and argument interaction have been proposed and studied, and this has led to the more recent study of computational models of argument. Argumentation, as a field within artificial intelligence (AI), is highly relevant for researchers interested in symbolic representations of knowledge and defeasible reasoning. The purpose of this handbook is to provide an open access and curated anthology for the argumentation research community. OHAAI is designed to serve as a research hub to keep track of the latest and upcoming PhD-driven research on the theory and application of argumentation in all areas related to AI.
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机器学习的普及增加了不公平模型的风险,该模型被部署在高级应用程序中,例如司法系统,药物/疫苗接种设计和医学诊断。尽管有有效的方法可以从头开始训练公平模型,但如何自动揭示和解释受过训练的模型的不公平仍然是一项艰巨的任务。以可解释的方式揭示机器学习模型的不公平是朝着公平和值得信赖的AI迈出的关键一步。在本文中,我们系统地解决了通过挖掘可解释的证据(Rumie)来揭示不公平模型的新任务。关键思想是以一组模型区分的数据实例的形式找到可靠的证据。为了使证据可以解释,我们还找到了一组人为理解的关键属性和决策规则,这些属性和决策规则表征了歧视的数据实例,并将其与其他非歧视数据区分开来。正如在许多现实世界数据集上进行的广泛实验所证明的那样,我们的方法找到了高度可解释和可靠的证据,可以有效揭示受过训练的模型的不公平性。此外,它比所有基线方法更可扩展。
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分类链是一种用于在多标签分类中建模标签依赖性的有效技术。但是,该方法需要标签的固定静态顺序。虽然理论上,任何顺序都足够了,实际上,该订单对最终预测的质量具有大量影响。动态分类链表示每个实例对分类的想法,可以动态选择预测标签的顺序。这种方法的天真实现的复杂性是禁止的,因为它需要训练一系列分类器,以满足标签的每种可能置换。为了有效地解决这个问题,我们提出了一种基于随机决策树的新方法,该方法可以动态地选择每个预测的标签排序。我们凭经验展示了下一个标签的动态选择,通过在否则不变的随机决策树模型下使用静态排序。 %和实验环境。此外,我们还展示了基于极端梯度提升树的替代方法,其允许更具目标的动态分级链训练。我们的结果表明,该变体优于随机决策树和其他基于树的多标签分类方法。更重要的是,动态选择策略允许大大加速培训和预测。
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We introduce a new rule-based optimization method for classification with constraints. The proposed method takes advantage of linear programming and column generation, and hence, is scalable to large datasets. Moreover, the method returns a set of rules along with their optimal weights indicating the importance of each rule for learning. Through assigning cost coefficients to the rules and introducing additional constraints, we show that one can also consider interpretability and fairness of the results. We test the performance of the proposed method on a collection of datasets and present two case studies to elaborate its different aspects. Our results show that a good compromise between interpretability and fairness on the one side, and accuracy on the other side, can be obtained by the proposed rule-based learning method.
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