在这篇扩展的抽象论文中,我们解决了因果机学习模型中的可解释性和针对性正则化的问题。特别是,我们专注于在观察到的混杂因素下估计单个因果/治疗效果的问题,这些问题可以控制并适应治疗对感兴趣结果的影响。针对因果环境调整的Black-Box ML模型在此任务中通常表现良好,但是它们缺乏可解释的输出,无法识别治疗异质性及其功能关系的主要驱动因素。我们提出了一种新型的深层反事实学习结构,用于估计可以同时进行的个人治疗效果:i)传达有针对性的正则化,并产生围绕感兴趣量的量化不确定性(即条件平均治疗效应); ii)解开协变量的基线预后和调节作用,并输出可解释的分数功能,描述了它们与结果的关系。最后,我们通过简单的模拟实验来证明该方法的使用。
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本文开发了贝叶斯因果林的稀疏诱导版本,最近提出的非参数因果回归模型采用贝叶斯添加剂回归树,专门设计用于使用观察数据来估计异质治疗效果。我们介绍的稀疏诱导组件是通过实证研究的动机,其中不是所有可用的协变量相关的,导致在估计个体治疗效果的兴趣表面底层的不同程度。在这项工作中提供的扩展版本,我们命名贝叶斯因果森林,配备了一对允许模型通过树集合中的相应数量的分裂调节每个协变量的重量。这些前瞻改善了模型对稀疏数据产生过程的适应性,并且允许在治疗效果估计的框架中进行完全贝叶斯特征缩收,从而揭示推动异质性的调节因子。此外,该方法允许先前了解相关的混杂协变量和对模型中掺入结果的影响的相对幅度。我们说明了我们在模拟研究中的方法的表现,与贝叶斯因果林和其他最先进的模型相比,展示如何与越来越多的协变量以及其如何处理强烈混淆的情景。最后,我们还提供了使用真实数据的应用程序的示例。
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大型观察数据越来越多地提供健康,经济和社会科学等学科,研究人员对因果问题而不是预测感兴趣。在本文中,从旨在调查参与学校膳食计划对健康指标的实证研究,研究了使用非参数回归的方法估算异质治疗效果的问题。首先,我们介绍了与观察或非完全随机数据进行因果推断相关的设置和相关的问题,以及如何在统计学习工具的帮助下解决这些问题。然后,我们审查并制定现有最先进的框架的统一分类,允许通过非参数回归模型来估算单个治疗效果。在介绍模型选择问题的简要概述后,我们说明了一些关于三种不同模拟研究的方法的性能。我们通过展示一些关于学校膳食计划数据的实证分析的一些方法的使用来结束。
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Computational units in artificial neural networks follow a simplified model of biological neurons. In the biological model, the output signal of a neuron runs down the axon, splits following the many branches at its end, and passes identically to all the downward neurons of the network. Each of the downward neurons will use their copy of this signal as one of many inputs dendrites, integrate them all and fire an output, if above some threshold. In the artificial neural network, this translates to the fact that the nonlinear filtering of the signal is performed in the upward neuron, meaning that in practice the same activation is shared between all the downward neurons that use that signal as their input. Dendrites thus play a passive role. We propose a slightly more complex model for the biological neuron, where dendrites play an active role: the activation in the output of the upward neuron becomes optional, and instead the signals going through each dendrite undergo independent nonlinear filterings, before the linear combination. We implement this new model into a ReLU computational unit and discuss its biological plausibility. We compare this new computational unit with the standard one and describe it from a geometrical point of view. We provide a Keras implementation of this unit into fully connected and convolutional layers and estimate their FLOPs and weights change. We then use these layers in ResNet architectures on CIFAR-10, CIFAR-100, Imagenette, and Imagewoof, obtaining performance improvements over standard ResNets up to 1.73%. Finally, we prove a universal representation theorem for continuous functions on compact sets and show that this new unit has more representational power than its standard counterpart.
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The text-to-image model Stable Diffusion has recently become very popular. Only weeks after its open source release, millions are experimenting with image generation. This is due to its ease of use, since all it takes is a brief description of the desired image to "prompt" the generative model. Rarely do the images generated for a new prompt immediately meet the user's expectations. Usually, an iterative refinement of the prompt ("prompt engineering") is necessary for satisfying images. As a new perspective, we recast image prompt engineering as interactive image retrieval - on an "infinite index". Thereby, a prompt corresponds to a query and prompt engineering to query refinement. Selected image-prompt pairs allow direct relevance feedback, as the model can modify an image for the refined prompt. This is a form of one-sided interactive retrieval, where the initiative is on the user side, whereas the server side remains stateless. In light of an extensive literature review, we develop these parallels in detail and apply the findings to a case study of a creative search task on such a model. We note that the uncertainty in searching an infinite index is virtually never-ending. We also discuss future research opportunities related to retrieval models specialized for generative models and interactive generative image retrieval. The application of IR technology, such as query reformulation and relevance feedback, will contribute to improved workflows when using generative models, while the notion of an infinite index raises new challenges in IR research.
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The connectivity-aware path design is crucial in the effective deployment of autonomous Unmanned Aerial Vehicles (UAVs). Recently, Reinforcement Learning (RL) algorithms have become the popular approach to solving this type of complex problem, but RL algorithms suffer slow convergence. In this paper, we propose a Transfer Learning (TL) approach, where we use a teacher policy previously trained in an old domain to boost the path learning of the agent in the new domain. As the exploration processes and the training continue, the agent refines the path design in the new domain based on the subsequent interactions with the environment. We evaluate our approach considering an old domain at sub-6 GHz and a new domain at millimeter Wave (mmWave). The teacher path policy, previously trained at sub-6 GHz path, is the solution to a connectivity-aware path problem that we formulate as a constrained Markov Decision Process (CMDP). We employ a Lyapunov-based model-free Deep Q-Network (DQN) to solve the path design at sub-6 GHz that guarantees connectivity constraint satisfaction. We empirically demonstrate the effectiveness of our approach for different urban environment scenarios. The results demonstrate that our proposed approach is capable of reducing the training time considerably at mmWave.
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In this paper, we elaborate on the design and discuss the results of a multi-agent simulation that we have developed using the PSI cognitive architecture. We demonstrate that imbuing agents with intrinsic needs for group affiliation, certainty and competence will lead to the emergence of social behavior among agents. This behavior expresses itself in altruism toward in-group agents and adversarial tendencies toward out-group agents. Our simulation also shows how parameterization can have dramatic effects on agent behavior. Introducing an out-group bias, for example, not only made agents behave aggressively toward members of the other group, but it also increased in-group cohesion. Similarly, environmental and situational factors facilitated the emergence of outliers: agents from adversarial groups becoming close friends. Overall, this simulation showcases the power of psychological frameworks, in general, and the PSI paradigm, in particular, to bring about human-like behavioral patterns in an emergent fashion.
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The detection of state-sponsored trolls acting in information operations is an unsolved and critical challenge for the research community, with repercussions that go beyond the online realm. In this paper, we propose a novel AI-based solution for the detection of state-sponsored troll accounts, which consists of two steps. The first step aims at classifying trajectories of accounts' online activities as belonging to either a state-sponsored troll or to an organic user account. In the second step, we exploit the classified trajectories to compute a metric, namely "troll score", which allows us to quantify the extent to which an account behaves like a state-sponsored troll. As a study case, we consider the troll accounts involved in the Russian interference campaign during the 2016 US Presidential election, identified as Russian trolls by the US Congress. Experimental results show that our approach identifies accounts' trajectories with an AUC close to 99\% and, accordingly, classify Russian trolls and organic users with an AUC of 97\%. Finally, we evaluate whether the proposed solution can be generalized to different contexts (e.g., discussions about Covid-19) and generic misbehaving users, showing promising results that will be further expanded in our future endeavors.
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该技术报告描述了在Robocup SPL(Mario)中计算视觉统计的模块化且可扩展的体系结构,该结构在Robocup 2022的SPL Open Research Challenge期间提出,该挑战在曼谷(泰国)举行。马里奥(Mario)是一个开源的,可用的软件应用程序,其最终目标是为Robocup SPL社区的发展做出贡献。Mario带有一个GUI,该GUI集成了多个机器学习和基于计算机视觉的功能,包括自动摄像机校准,背景减法,同型计算,玩家 +球跟踪和本地化,NAO机器人姿势估计和跌落检测。马里奥(Mario)被排名第一。1在开放研究挑战中。
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聊天机器人用于许多应用程序中,例如自动化代理,智能家庭助理,在线游戏中的互动角色等。因此,确保他们不会以不希望的方式行事,对用户提供令人反感或有毒的反应。这并不是一项琐碎的任务,因为最先进的聊天机器人模型是在从互联网公开收集的大型公共数据集上培训的。本文提出了对聊天机器人中毒性的首次大规模测量。我们表明,公开可用的聊天机器人很容易在喂养有毒的查询时提供有毒的反应。更令人担忧的是,一些无毒的查询也会触发有毒反应。然后,我们着手设计和实验攻击,即毒性,该攻击依赖于微调的GPT-2来产生无毒的查询,使聊天机器人以有毒的方式做出反应。我们广泛的实验评估表明,我们的攻击对公共聊天机器人模型有效,并且优于先前工作提出的手动制作的恶意查询。我们还评估了针对毒性的三种防御机制,表明它们要么以影响聊天机器人的效用而降低攻击性能,要么仅有效地减轻了一部分攻击。这强调了对计算机安全和在线安全社区进行更多研究的需求,以确保聊天机器人模型不会伤害其用户。总体而言,我们有信心有毒可以用作审计工具,我们的工作将为设计更有效的聊天机器人安全防御措施铺平道路。
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