Statistical Learning
Correlation inference attacks against machine learning models
Creţu, Ana-Maria, Guépin, Florent, de Montjoye, Yves-Alexandre
Machine learning models are often trained on sensitive and proprietary datasets. Yet what -- and under which conditions -- a model leaks about its dataset, is not well understood. Most previous works study the leakage of information about an individual record. Yet in many situations, global dataset information such as its underlying distribution, e.g. $k$-way marginals or correlations are similarly sensitive or secret. We here explore for the first time whether a model leaks information about the correlations between the input variables of its training dataset, something we name correlation inference attack. We first propose a model-less attack, showing how an attacker can exploit the spherical parametrization of correlation matrices to make an informed guess based on the correlations between the input variables and the target variable alone. Second, we propose a model-based attack, showing how an attacker can exploit black-box access to the model to infer the correlations using shadow models trained on synthetic datasets. Our synthetic data generation approach combines Gaussian copula-based generative modeling with a carefully adapted procedure for sampling correlation matrices under constraints. Third, we evaluate our model-based attack against Logistic Regression and Multilayer Perceptron models and show it to strongly outperform the model-less attack on three real-world tabular datasets, indicating that the models leak information about the correlations. We also propose a novel correlation inference-based attribute inference attack (CI-AIA), and show it to obtain state-of-the-art performance. Taken together, our results show how attackers can use the model to extract information about the dataset distribution, and use it to improve their prior on sensitive attributes of individual records.
Unsupervised Learning under Latent Label Shift
Roberts, Manley, Mani, Pranav, Garg, Saurabh, Lipton, Zachary C.
What sorts of structure might enable a learner to discover classes from unlabeled data? Traditional approaches rely on feature-space similarity and heroic assumptions on the data. In this paper, we introduce unsupervised learning under Latent Label Shift (LLS), where we have access to unlabeled data from multiple domains such that the label marginals $p_d(y)$ can shift across domains but the class conditionals $p(\mathbf{x}|y)$ do not. This work instantiates a new principle for identifying classes: elements that shift together group together. For finite input spaces, we establish an isomorphism between LLS and topic modeling: inputs correspond to words, domains to documents, and labels to topics. Addressing continuous data, we prove that when each label's support contains a separable region, analogous to an anchor word, oracle access to $p(d|\mathbf{x})$ suffices to identify $p_d(y)$ and $p_d(y|\mathbf{x})$ up to permutation. Thus motivated, we introduce a practical algorithm that leverages domain-discriminative models as follows: (i) push examples through domain discriminator $p(d|\mathbf{x})$; (ii) discretize the data by clustering examples in $p(d|\mathbf{x})$ space; (iii) perform non-negative matrix factorization on the discrete data; (iv) combine the recovered $p(y|d)$ with the discriminator outputs $p(d|\mathbf{x})$ to compute $p_d(y|x) \; \forall d$. With semi-synthetic experiments, we show that our algorithm can leverage domain information to improve upon competitive unsupervised classification methods. We reveal a failure mode of standard unsupervised classification methods when feature-space similarity does not indicate true groupings, and show empirically that our method better handles this case. Our results establish a deep connection between distribution shift and topic modeling, opening promising lines for future work.
Desynchronous Learning in a Physics-Driven Learning Network
Wycoff, Jacob F, Dillavou, Sam, Stern, Menachem, Liu, Andrea J, Durian, Douglas J
Here we demonstrate that desynchronous implementation of coupled learning is effective in self-adjusting resistor networks, in both simulation and experiment. Furthermore, we Learning is a special case of memory [1, 2], where the goal show that desynchronous learning can actually improve performance is to encode targeted functional responses in a network [3-by allowing the system to evolve indefinitely, escaping 6]. Artificial Neural Networks (ANNs) are complex functions local minima. We draw a direct analogy between stochastic designed to achieve such targeted responses. These networks gradient descent and desynchronous learning, and show are trained by using gradient descent on a cost function, they have similar effects on the learning degrees of freedom which evolves the system's parameters until a local minimum in our system. Thus we are able to remove the final vestige of is found [7, 8]. Typically, this algorithm is modified non-locality from our physics-driven learning network, moving such that subsections (batches) of data are used at each training it closer to biological implementations of learning. The step, effectively adding noise to the gradient calculation, ability to learn with entirely independent learning elements is known as Stochastic Gradient Descent (SGD) [9]. This algorithm expected to greatly improve the scalability of such physical produces more generalizable results [10-12], i.e. better learning systems.
A Hybrid Statistical-Machine Learning Approach for Analysing Online Customer Behavior: An Empirical Study
Alizamir, Saed, Bandara, Kasun, Eshragh, Ali, Iravani, Foaad
We apply classical statistical methods in conjunction with the state-of-the-art machine learning techniques to develop a hybrid interpretable model to analyse 454,897 online customers' behavior for a particular product category at the largest online retailer in China, that is JD. While most mere machine learning methods are plagued by the lack of interpretability in practice, our novel hybrid approach will address this practical issue by generating explainable output. This analysis involves identifying what features and characteristics have the most significant impact on customers' purchase behavior, thereby enabling us to predict future sales with a high level of accuracy, and identify the most impactful variables. Our results reveal that customers' product choice is insensitive to the promised delivery time, but this factor significantly impacts customers' order quantity. We also show that the effectiveness of various discounting methods depends on the specific product and the discount size. We identify product classes for which certain discounting approaches are more effective and provide recommendations on better use of different discounting tools. Customers' choice behavior across different product classes is mostly driven by price, and to a lesser extent, by customer demographics. The former finding asks for exercising care in deciding when and how much discount should be offered, whereas the latter identifies opportunities for personalized ads and targeted marketing. Further, to curb customers' batch ordering behavior and avoid the undesirable Bullwhip effect, JD should improve its logistics to ensure faster delivery of orders.
Open-Source Ground-based Sky Image Datasets for Very Short-term Solar Forecasting, Cloud Analysis and Modeling: A Comprehensive Survey
Nie, Yuhao, Li, Xiatong, Paletta, Quentin, Aragon, Max, Scott, Andea, Brandt, Adam
Sky-image-based solar forecasting using deep learning has been recognized as a promising approach in reducing the uncertainty in solar power generation. However, one of the biggest challenges is the lack of massive and diversified sky image samples. In this study, we present a comprehensive survey of open-source ground-based sky image datasets for very short-term solar forecasting (i.e., forecasting horizon less than 30 minutes), as well as related research areas which can potentially help improve solar forecasting methods, including cloud segmentation, cloud classification and cloud motion prediction. We first identify 72 open-source sky image datasets that satisfy the needs of machine/deep learning. Then a database of information about various aspects of the identified datasets is constructed. To evaluate each surveyed datasets, we further develop a multi-criteria ranking system based on 8 dimensions of the datasets which could have important impacts on usage of the data. Finally, we provide insights on the usage of these datasets for different applications. We hope this paper can provide an overview for researchers who are looking for datasets for very short-term solar forecasting and related areas.
Creating a Machine Learning App using FastAPI and Deploying it Using Kubernetes
FastAPI is a new Python-based web framework used to create Web APIs. FastAPI is fast when serving your application, also enhances the performance of our application. Note: for you to follow along easily, use Google Colab. It's an easy-to-use platform to get started quickly while building models. We will build a machine learning model that will predict the nationality of individuals using their names. This is a simple model that will explain the key concepts used in machine learning modeling. The dataset used will contains common names of people and their nationalities. Pandas is a software library written for the Python programming language for data manipulation and analysis.
Rethinking Survival Analysis: How to Make your Model Produce Survival Curves
In data-driven companies, time-to-event applications assume a crucial role in decision-making (also more than we can imagine). With time-to-event analysis, we are referring to all the techniques used to measure the time which elapses until some events of interest happen. This straightforward definition may immediately outline all the benefits of developing time-event applications in business contexts (and not only). Time-to-event origins are related to the medical field to answer questions like: "how long do the individuals under analysis live?". For this reason, the terms survival and time-to-event are usually used as synonyms.
How much is Artificial Intelligence Course Fee in Gurgaon?
An area of computer science that deals with data and analytics are referred to as artificial intelligence. It speaks to a device's or program's capacity to learn, use, and act in a manner akin to a person's. Planning, solving problems, and reasoning are a few examples of these activities. AI is a technology that is revolutionising every aspect of life despite the general lack of knowledge of it. It is a comprehensive tool that allows people to reconsider how we combine information, evaluate data, and use the ensuing insights to enhance decision-making.
#NeurIPS2022 outstanding paper – Gradient descent: the ultimate optimizer
Kartik Chandra, Audrey Xie, Jonathan Ragan-Kelley and Erik Meijer won a NeurIPS 2022 outstanding paper award for their work Gradient descent: the ultimate optimizer. Here, they tell us more about their work, the methodology and their main findings. Our paper studies the classic problem of "hyperparameter optimization". Nearly all of today's machine learning algorithms use a process called "stochastic gradient descent" (SGD) to train neural networks. SGD requires users to pick certain settings, or "hyperparameters," before running it.
Context-Aware Ensemble Learning for Time Series
Fazla, Arda, Aydin, Mustafa Enes, Tamyigit, Orhun, Kozat, Suleyman Serdar
We investigate ensemble methods for prediction in an online setting. Unlike all the literature in ensembling, for the first time, we introduce a new approach using a meta learner that effectively combines the base model predictions via using a superset of the features that is the union of the base models' feature vectors instead of the predictions themselves. Here, our model does not use the predictions of the base models as inputs to a machine learning algorithm, but choose the best possible combination at each time step based on the state of the problem. We explore three different constraint spaces for the ensembling of the base learners that linearly combines the base predictions, which are convex combinations where the components of the ensembling vector are all nonnegative and sum up to 1; affine combinations where the weight vector components are required to sum up to 1; and the unconstrained combinations where the components are free to take any real value. The constraints are both theoretically analyzed under known statistics and integrated into the learning procedure of the meta learner as a part of the optimization in an automated manner. To show the practical efficiency of the proposed method, we employ a gradient-boosted decision tree and a multi-layer perceptron separately as the meta learners. Our framework is generic so that one can use other machine learning architectures as the ensembler as long as they allow for a custom differentiable loss for minimization. We demonstrate the learning behavior of our algorithm on synthetic data and the significant performance improvements over the conventional methods over various real life datasets, extensively used in the well-known data competitions. Furthermore, we openly share the source code of the proposed method to facilitate further research and comparison.