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 hyper-parameter tuning



Hyper-parameter Tuning for Adversarially Robust Models

Mendes, Pedro, Romano, Paolo, Garlan, David

arXiv.org Artificial Intelligence

This work focuses on the problem of hyper-parameter tuning (HPT) for robust (i.e., adversarially trained) models, shedding light on the new challenges and opportunities arising during the HPT process for robust models. To this end, we conduct an extensive experimental study based on 3 popular deep models, in which we explore exhaustively 9 (discretized) HPs, 2 fidelity dimensions, and 2 attack bounds, for a total of 19208 configurations (corresponding to 50 thousand GPU hours). Through this study, we show that the complexity of the HPT problem is further exacerbated in adversarial settings due to the need to independently tune the HPs used during standard and adversarial training: succeeding in doing so (i.e., adopting different HP settings in both phases) can lead to a reduction of up to 80% and 43% of the error for clean and adversarial inputs, respectively. On the other hand, we also identify new opportunities to reduce the cost of HPT for robust models. Specifically, we propose to leverage cheap adversarial training methods to obtain inexpensive, yet highly correlated, estimations of the quality achievable using state-of-the-art methods. We show that, by exploiting this novel idea in conjunction with a recent multi-fidelity optimizer (taKG), the efficiency of the HPT process can be enhanced by up to 2.1 .


Hyper-parameter Tuning for Fair Classification without Sensitive Attribute Access

Veldanda, Akshaj Kumar, Brugere, Ivan, Dutta, Sanghamitra, Mishler, Alan, Garg, Siddharth

arXiv.org Artificial Intelligence

Fair machine learning methods seek to train models that balance model performance across demographic subgroups defined over sensitive attributes like race and gender. Although sensitive attributes are typically assumed to be known during training, they may not be available in practice due to privacy and other logistical concerns. Recent work has sought to train fair models without sensitive attributes on training data. However, these methods need extensive hyper-parameter tuning to achieve good results, and hence assume that sensitive attributes are known on validation data. However, this assumption too might not be practical. Here, we propose Antigone, a framework to train fair classifiers without access to sensitive attributes on either training or validation data. Instead, we generate pseudo sensitive attributes on the validation data by training a biased classifier and using the classifier's incorrectly (correctly) labeled examples as proxies for minority (majority) groups. Since fairness metrics like demographic parity, equal opportunity and subgroup accuracy can be estimated to within a proportionality constant even with noisy sensitive attribute information, we show theoretically and empirically that these proxy labels can be used to maximize fairness under average accuracy constraints. Key to our results is a principled approach to select the hyper-parameters of the biased classifier in a completely unsupervised fashion (meaning without access to ground truth sensitive attributes) that minimizes the gap between fairness estimated using noisy versus ground-truth sensitive labels.


The Data Science of Hyper-Parameter Tuning

#artificialintelligence

The inner operations of advanced machine learning models are nebulous to the average business user, regulator, or customer impacted by the outputs of this form of statistical Artificial Intelligence. At best, such laymen are vaguely aware that neural networks, for example, function in a manner that's somewhat similar to how the human brain does. The most sophisticated may have heard something about the notion of parameters; most are blissfully unaware of the presence of hyper-parameters or their import to applications of deep learning. "Basically, in [these] machine learning models, there are two sets of parameters," explained Suman Bera, Senior Software Engineer at Katana Graph. "One set of parameters you are trying to learn through your machine learning algorithm. And, there is another set of parameters which are predefined. You are not trying to learn them. Hyper-parameters are invaluable to devising accurate predictions from advanced machine learning models, which are oftentimes ...


Common Mistakes in Hyper-Parameters Tuning

#artificialintelligence

Although the principle is straightforward, this method is still error-prone. Here is a list of the most common mistakes I have encountered. This error I've seen it happen quite a few times. Students define a grid on a parameter, run GridSearchCV, extract the hyper-parameter value corresponding to the best score, and …. that's it! Depending on how well the grid was defined, just looking at the best score and its corresponding hyper-parameter value might not be enough to draw the right conclusions.


Algorithms for Advanced Hyper-Parameter Optimization/Tuning - KDnuggets

#artificialintelligence

Most Professional Machine Learning practitioners follow the ML Pipeline as a standard, to keep their work efficient and to keep the flow of work. A pipeline is created to allow data flow from its raw format to some useful information. All sub-fields in this pipeline's modules are equally important for us to produce quality results, and one of them is Hyper-Parameter Tuning. Most of us know the best way to proceed with Hyper-Parameter Tuning is to use the GridSearchCV or RandomSearchCV from the sklearn module. But apart from these algorithms, there are many other Advanced methods for Hyper-Parameter Tuning.


How To Use Keras Tuner for Hyper-parameter Tuning

#artificialintelligence

In computer vision, we often build Convolution neural networks for different problems dealing with images like image classification, object detection, etc. In image classification tasks a CNN network is built using a combination of different convolution layers, pooling layers, dropouts, and at last fully connected layers. But while building this type of networks we define different sizes of kernels to extract feature maps and different neurons for different layers. We do not have a fixed rule of defining the number of layers, neurons, and kernel size. Keras Tuner is a library that resolves this problem and gives us the optimal parameters to attain high accuracy.


On Hyper-parameter Tuning for Stochastic Optimization Algorithms

Zhang, Haotian, Sun, Jianyong, Xu, Zongben

arXiv.org Machine Learning

This paper proposes the first-ever algorithmic framework for tuning hyper-parameters of stochastic optimization algorithm based on reinforcement learning. Hyper-parameters impose significant influences on the performance of stochastic optimization algorithms, such as evolutionary algorithms (EAs) and meta-heuristics. Yet, it is very time-consuming to determine optimal hyper-parameters due to the stochastic nature of these algorithms. We propose to model the tuning procedure as a Markov decision process, and resort the policy gradient algorithm to tune the hyper-parameters. Experiments on tuning stochastic algorithms with different kinds of hyper-parameters (continuous and discrete) for different optimization problems (continuous and discrete) show that the proposed hyper-parameter tuning algorithms do not require much less running times of the stochastic algorithms than bayesian optimization method. The proposed framework can be used as a standard tool for hyper-parameter tuning in stochastic algorithms.