Reformulating the history matching problem from a least-square mathematical optimization problem into a Markov Decision Process introduces a method in which reinforcement learning can be utilized to solve the problem. This method provides a mechanism where an artificial deep neural network agent can interact with the reservoir simulator and find multiple different solutions to the problem. Such formulation allows for solving the problem in parallel by launching multiple concurrent environments enabling the agent to learn simultaneously from all the environments at once, achieving significant speed up.
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评估网络协议的真实表现是具有挑战性的。随机控制试验(RCT)对大多数研究人员来说是昂贵的并且无法进入,而专业设计的模拟器则无法捕获真实网络中的复杂行为。我们呈现MaunAlim,一种数据驱动的模拟器,用于解决这一挑战的网络协议。由于数据收集期间使用的协议引入的偏差,从观察数据中学习网络行为是复杂的。 MakAlAIM在一组协议下使用来自初始RCT的迹线来学习因果网络模型,有效地去除数据中存在的偏差。然后,使用此模型,可以在同一迹线上模拟任何协议(即,用于反事实预测)。因果的关键是对来自来自RCT的训练数据引起的分布修正因的对抗性神经网络培训进行了新的使用。我们对实际和合成数据集的MAURALAIM的广泛评估以及来自河豚视频流系统的两种用例,包括来自河豚视频流系统的超过九个月的实际数据,表明它提供了准确的反事预测,将预测误差降低了44%和53%平均值与专家设计和标准的监督学习基线相比。
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我们考虑在严重数据稀缺下具有异质代理的离线强化学习(RL),即,我们只观察一个未知潜在的次优政策下的每个代理的单一历史轨迹。我们发现,即使对于常见的“解决”基准设置(如“Makescar”和“Cartpole”),我们发现最先进的离线和基于模型的RL方法的性能显着降低了显着的数据可用性。为了解决这一挑战,我们提出了一种基于模型的离线RL方法,该方法首先通过在学习政策之前共同使用所有代理商的历史轨迹来学习每个代理的个性化模拟器。我们这样做是这样做的,指出代理商的过渡动态可以表示为与代理商,州和行动相关的潜在因子的潜在函数;随后,理论上,理论上建立了这种函数通过可分离代理,状态和动作潜在函数的“低级”分解良好地近似。此表示表明,一个简单的正则化的神经网络架构,以有效地学习每个代理的过渡动态,即使具有稀缺,离线数据。我们在多个基准环境和RL方法中执行大量实验。我们的方法的一致性提高,在国家动态预测和最终奖励方面衡量,确认了我们框架在利用有限的历史数据方面的效力,以同时学习跨代理商的个性化政策。
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我们介绍和分析了多元奇异频谱分析(MSSA)的变体,这是一种流行的时间序列方法,用于启用和预测多元时间序列。在我们介绍的时空因素模型下,给定$ n $时间序列和$ t $观测时间序列,我们为插补和样本外预测均有效地扩展为$ 1 / \ sqrt,为预测和样本预测有效地缩放均值{\ min(n,t)t} $。这是一个改进:(i)$ 1 /\ sqrt {t} $ SSA的错误缩放,MSSA限制对单变量时间序列; (ii)$ 1/\ min(n,t)$对于不利用数据中时间结构的矩阵估计方法的错误缩放。我们引入的时空模型包括:谐波,多项式,可区分的周期函数和持有人连续函数的任何有限总和和产物。在时空因素模型下,我们的样本外预测结果可能对在线学习具有独立的兴趣。从经验上讲,在基准数据集上,我们的MSSA变体通过最先进的神经网络时间序列方法(例如,DEEPAR,LSTM)竞争性能,并且明显优于诸如矢量自动化(VAR)之类的经典方法。最后,我们提出了MSSA的扩展:(i)估计时间序列的时变差异的变体; (ii)一种张量变体,对于$ n $和$ t $的某些制度具有更好的样本复杂性。
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We derive a set of causal deep neural networks whose architectures are a consequence of tensor (multilinear) factor analysis. Forward causal questions are addressed with a neural network architecture composed of causal capsules and a tensor transformer. The former estimate a set of latent variables that represent the causal factors, and the latter governs their interaction. Causal capsules and tensor transformers may be implemented using shallow autoencoders, but for a scalable architecture we employ block algebra and derive a deep neural network composed of a hierarchy of autoencoders. An interleaved kernel hierarchy preprocesses the data resulting in a hierarchy of kernel tensor factor models. Inverse causal questions are addressed with a neural network that implements multilinear projection and estimates the causes of effects. As an alternative to aggressive bottleneck dimension reduction or regularized regression that may camouflage an inherently underdetermined inverse problem, we prescribe modeling different aspects of the mechanism of data formation with piecewise tensor models whose multilinear projections are well-defined and produce multiple candidate solutions. Our forward and inverse neural network architectures are suitable for asynchronous parallel computation.
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User equipment is one of the main bottlenecks facing the gaming industry nowadays. The extremely realistic games which are currently available trigger high computational requirements of the user devices to run games. As a consequence, the game industry has proposed the concept of Cloud Gaming, a paradigm that improves gaming experience in reduced hardware devices. To this end, games are hosted on remote servers, relegating users' devices to play only the role of a peripheral for interacting with the game. However, this paradigm overloads the communication links connecting the users with the cloud. Therefore, service experience becomes highly dependent on network connectivity. To overcome this, Cloud Gaming will be boosted by the promised performance of 5G and future 6G networks, together with the flexibility provided by mobility in multi-RAT scenarios, such as WiFi. In this scope, the present work proposes a framework for measuring and estimating the main E2E metrics of the Cloud Gaming service, namely KQIs. In addition, different machine learning techniques are assessed for predicting KQIs related to Cloud Gaming user's experience. To this end, the main key quality indicators (KQIs) of the service such as input lag, freeze percent or perceived video frame rate are collected in a real environment. Based on these, results show that machine learning techniques provide a good estimation of these indicators solely from network-based metrics. This is considered a valuable asset to guide the delivery of Cloud Gaming services through cellular communications networks even without access to the user's device, as it is expected for telecom operators.
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Multi-view projection techniques have shown themselves to be highly effective in achieving top-performing results in the recognition of 3D shapes. These methods involve learning how to combine information from multiple view-points. However, the camera view-points from which these views are obtained are often fixed for all shapes. To overcome the static nature of current multi-view techniques, we propose learning these view-points. Specifically, we introduce the Multi-View Transformation Network (MVTN), which uses differentiable rendering to determine optimal view-points for 3D shape recognition. As a result, MVTN can be trained end-to-end with any multi-view network for 3D shape classification. We integrate MVTN into a novel adaptive multi-view pipeline that is capable of rendering both 3D meshes and point clouds. Our approach demonstrates state-of-the-art performance in 3D classification and shape retrieval on several benchmarks (ModelNet40, ScanObjectNN, ShapeNet Core55). Further analysis indicates that our approach exhibits improved robustness to occlusion compared to other methods. We also investigate additional aspects of MVTN, such as 2D pretraining and its use for segmentation. To support further research in this area, we have released MVTorch, a PyTorch library for 3D understanding and generation using multi-view projections.
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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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Recently, Person Re-Identification (Re-ID) has received a lot of attention. Large datasets containing labeled images of various individuals have been released, allowing researchers to develop and test many successful approaches. However, when such Re-ID models are deployed in new cities or environments, the task of searching for people within a network of security cameras is likely to face an important domain shift, thus resulting in decreased performance. Indeed, while most public datasets were collected in a limited geographic area, images from a new city present different features (e.g., people's ethnicity and clothing style, weather, architecture, etc.). In addition, the whole frames of the video streams must be converted into cropped images of people using pedestrian detection models, which behave differently from the human annotators who created the dataset used for training. To better understand the extent of this issue, this paper introduces a complete methodology to evaluate Re-ID approaches and training datasets with respect to their suitability for unsupervised deployment for live operations. This method is used to benchmark four Re-ID approaches on three datasets, providing insight and guidelines that can help to design better Re-ID pipelines in the future.
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Recent advances in Neural Radiance Fields (NeRFs) treat the problem of novel view synthesis as Sparse Radiance Field (SRF) optimization using sparse voxels for efficient and fast rendering (plenoxels,InstantNGP). In order to leverage machine learning and adoption of SRFs as a 3D representation, we present SPARF, a large-scale ShapeNet-based synthetic dataset for novel view synthesis consisting of $\sim$ 17 million images rendered from nearly 40,000 shapes at high resolution (400 X 400 pixels). The dataset is orders of magnitude larger than existing synthetic datasets for novel view synthesis and includes more than one million 3D-optimized radiance fields with multiple voxel resolutions. Furthermore, we propose a novel pipeline (SuRFNet) that learns to generate sparse voxel radiance fields from only few views. This is done by using the densely collected SPARF dataset and 3D sparse convolutions. SuRFNet employs partial SRFs from few/one images and a specialized SRF loss to learn to generate high-quality sparse voxel radiance fields that can be rendered from novel views. Our approach achieves state-of-the-art results in the task of unconstrained novel view synthesis based on few views on ShapeNet as compared to recent baselines. The SPARF dataset will be made public with the code and models on the project website https://abdullahamdi.com/sparf/ .
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