Performance Analysis
Interpretable Machine Learning: Fundamental Principles and 10 Grand Challenges
Rudin, Cynthia, Chen, Chaofan, Chen, Zhi, Huang, Haiyang, Semenova, Lesia, Zhong, Chudi
Interpretability in machine learning (ML) is crucial for high stakes decisions and troubleshooting. In this work, we provide fundamental principles for interpretable ML, and dispel common misunderstandings that dilute the importance of this crucial topic. We also identify 10 technical challenge areas in interpretable machine learning and provide history and background on each problem. Some of these problems are classically important, and some are recent problems that have arisen in the last few years. These problems are: (1) Optimizing sparse logical models such as decision trees; (2) Optimization of scoring systems; (3) Placing constraints into generalized additive models to encourage sparsity and better interpretability; (4) Modern case-based reasoning, including neural networks and matching for causal inference; (5) Complete supervised disentanglement of neural networks; (6) Complete or even partial unsupervised disentanglement of neural networks; (7) Dimensionality reduction for data visualization; (8) Machine learning models that can incorporate physics and other generative or causal constraints; (9) Characterization of the "Rashomon set" of good models; and (10) Interpretable reinforcement learning. This survey is suitable as a starting point for statisticians and computer scientists interested in working in interpretable machine learning.
Predicting Hard Drive Failure with Machine Learning - Datto Engineering Blog
We've all had a hard drive fail on us, and often it's as sudden as booting your machine and realizing you can't access a bunch of your files. It's especially not fun when you have an entire data center full of drives that are all important to keeping your business running. What if we could predict when one of those drives would fail, and get ahead of it by preemptively replacing the hardware before the data is lost? This is where the history of predictive drive failure at Datto begins. First and foremost, to make a prediction you need data. Hard drives have a built-in utility called SMART (Self-Monitoring, Analysis and Reporting Technology) that reports an array of statistics about how the drive is functioning. Here's an abbreviated view of what that looks like: Datto collects a report like this from each hard drive in its storage servers once per day. Each attribute in the report has three important numbers associated with it: value, thresh, and worst. Each attribute also has a feature named raw_value, but this is discarded due to inconsistent reporting standards between drive manufacturers. The value reflects how well the drive is operating with respect to the attribute, with 1 being the worst and 253 being the best. The initial value is arbitrarily determined by the manufacturer, and can vary by drive model. Thresh: A threshold below which the value should not fall in normal operation.
Empirical Analysis of Machine Learning Configurations for Prediction of Multiple Organ Failure in Trauma Patients
Wang, Yuqing, Zhao, Yun, Callcut, Rachael, Petzold, Linda
Multiple organ failure (MOF) is a life-threatening condition. Due to its urgency and high mortality rate, early detection is critical for clinicians to provide appropriate treatment. In this paper, we perform quantitative analysis on early MOF prediction with comprehensive machine learning (ML) configurations, including data preprocessing (missing value treatment, label balancing, feature scaling), feature selection, classifier choice, and hyperparameter tuning. Results show that classifier choice impacts both the performance improvement and variation most among all the configurations. In general, complex classifiers including ensemble methods can provide better performance than simple classifiers. However, blindly pursuing complex classifiers is unwise as it also brings the risk of greater performance variation.
The Case for High-Accuracy Classification: Think Small, Think Many!
Hosseini, Mohammad, Hasan, Mahmudul
To facilitate implementation of high-accuracy deep neural networks especially on resource-constrained devices, maintaining low computation requirements is crucial. Using very deep models for classification purposes not only decreases the neural network training speed and increases the inference time, but also need more data for higher prediction accuracy and to mitigate false positives. In this paper, we propose an efficient and lightweight deep classification ensemble structure based on a combination of simple color features, which is particularly designed for "high-accuracy" image classifications with low false positives. We designed, implemented, and evaluated our approach for explosion detection use-case applied to images and videos. Our evaluation results based on a large test test show considerable improvements on the prediction accuracy compared to the popular ResNet-50 model, while benefiting from 7.64x faster inference and lower computation cost. While we applied our approach to explosion detection, our approach is general and can be applied to other similar classification use cases as well. Given the insight gained from our experiments, we hence propose a "think small, think many" philosophy in classification scenarios: that transforming a single, large, monolithic deep model into a verification-based step model ensemble of multiple small, simple, lightweight models with narrowed-down color spaces can possibly lead to predictions with higher accuracy.
Evaluation of soccer team defense based on prediction models of ball recovery and being attacked
Toda, Kosuke, Teranishi, Masakiyo, Kushiro, Keisuke, Fujii, Keisuke
With the development of measurement technology, data on the movements of actual games in various sports are available and are expected to be used for planning and evaluating the tactics and strategy. In particular, defense in team sports is generally difficult to be evaluated because of the lack of statistical data. Conventional evaluation methods based on predictions of scores are considered unreliable and predict rare events throughout the entire game, and it is difficult to evaluate various plays leading up to a score. On the other hand, evaluation methods based on certain plays that lead to scoring and dominant regions are sometimes unsuitable to evaluate the performance (e.g., goals scored) of players and teams. In this study, we propose a method to evaluate team defense from a comprehensive perspective related to team performance based on the prediction of ball recovery and being attacked, which occur more frequently than goals, using player actions and positional data of all players and the ball. Using data from 45 soccer matches, we examined the relationship between the proposed index and team performance in actual matches and throughout a season. Results show that the proposed classifiers more accurately predicted the true events than the existing classifiers which were based on rare events (i.e., goals). Also, the proposed index had a moderate correlation with the long-term outcomes of the season. These results suggest that the proposed index might be a more reliable indicator rather than winning or losing with the inclusion of accidental factors.
Different Data Splitting Cross-Validation Strategies with Python
In this article, we will cover the cross-validation methods to split the data set uniformly to get good performance on prediction. We see how our data is splitting into the training set and testing set in our machine learning algorithm. But, if you ever tried to think that these two sets are enough to build the production model. From my point of view, we should include the validation set before we predict the test set. It is important because if the model gets overfit then we can tuning the hyperparameters after checking with the validation set and set the good parameter for our test set.
Interpretable Distance Metric Learning for Handwritten Chinese Character Recognition
Dong, Boxiang, Varde, Aparna S., Stevanovic, Danilo, Wang, Jiayin, Zhao, Liang
Handwriting recognition is of crucial importance to both Human Computer Interaction (HCI) and paperwork digitization. In the general field of Optical Character Recognition (OCR), handwritten Chinese character recognition faces tremendous challenges due to the enormously large character sets and the amazing diversity of writing styles. Learning an appropriate distance metric to measure the difference between data inputs is the foundation of accurate handwritten character recognition. Existing distance metric learning approaches either produce unacceptable error rates, or provide little interpretability in the results. In this paper, we propose an interpretable distance metric learning approach for handwritten Chinese character recognition. The learned metric is a linear combination of intelligible base metrics, and thus provides meaningful insights to ordinary users. Our experimental results on a benchmark dataset demonstrate the superior efficiency, accuracy and interpretability of our proposed approach.
Decision Theoretic Bootstrapping
Tavallali, Peyman, Bajgiran, Hamed Hamze, Esaid, Danial J., Owhadi, Houman
The design and testing of supervised machine learning models combine two fundamental distributions: (1) the training data distribution (2) the testing data distribution. Although these two distributions are identical and identifiable when the data set is infinite; they are imperfectly known (and possibly distinct) when the data is finite (and possibly corrupted) and this uncertainty must be taken into account for robust Uncertainty Quantification (UQ). We present a general decision-theoretic bootstrapping solution to this problem: (1) partition the available data into a training subset and a UQ subset (2) take $m$ subsampled subsets of the training set and train $m$ models (3) partition the UQ set into $n$ sorted subsets and take a random fraction of them to define $n$ corresponding empirical distributions $\mu_{j}$ (4) consider the adversarial game where Player I selects a model $i\in\left\{ 1,\ldots,m\right\} $, Player II selects the UQ distribution $\mu_{j}$ and Player I receives a loss defined by evaluating the model $i$ against data points sampled from $\mu_{j}$ (5) identify optimal mixed strategies (probability distributions over models and UQ distributions) for both players. These randomized optimal mixed strategies provide optimal model mixtures and UQ estimates given the adversarial uncertainty of the training and testing distributions represented by the game. The proposed approach provides (1) some degree of robustness to distributional shift in both the distribution of training data and that of the testing data (2) conditional probability distributions on the output space forming aleatory representations of the uncertainty on the output as a function of the input variable.
EX-RAY: Distinguishing Injected Backdoor from Natural Features in Neural Networks by Examining Differential Feature Symmetry
Liu, Yingqi, Shen, Guangyu, Tao, Guanhong, Wang, Zhenting, Ma, Shiqing, Zhang, Xiangyu
Backdoor attack injects malicious behavior to models such that inputs embedded with triggers are misclassified to a target label desired by the attacker. However, natural features may behave like triggers, causing misclassification once embedded. While they are inevitable, mis-recognizing them as injected triggers causes false warnings in backdoor scanning. A prominent challenge is hence to distinguish natural features and injected backdoors. We develop a novel symmetric feature differencing method that identifies a smallest set of features separating two classes. A backdoor is considered injected if the corresponding trigger consists of features different from the set of features distinguishing the victim and target classes. We evaluate the technique on thousands of models, including both clean and trojaned models, from the TrojAI rounds 2-4 competitions and a number of models on ImageNet. Existing backdoor scanning techniques may produce hundreds of false positives (i.e., clean models recognized as trojaned). Our technique removes 78-100% of the false positives (by a state-of-the-art scanner ABS) with a small increase of false negatives by 0-30%, achieving 17-41% overall accuracy improvement, and facilitates achieving top performance on the leaderboard. It also boosts performance of other scanners. It outperforms false positive removal methods using L2 distance and attribution techniques. We also demonstrate its potential in detecting a number of semantic backdoor attacks.
Non-invasive SKIN tests can detect Covid-19 with 83% accuracy
Covid-19 can be accurately detected by skin swabs rubbed on the face, neck or back, a study suggests. Currently, the only way to reliably detect Covid-19 is with highly-invasive swabs which go up the nose or to the back of the throat. But University of Surrey researchers say sebum -- a waxy substance made by glands in the skin -- is altered by the coronavirus and can therefore be used to detect signs of infection. Currently, the only way to reliably detect Covid-19 is with highly-invasive swabs which go up the nose or to the back of the throat. Sixty-seven hospitalised patients were recruited for the study between May and June 2020.