Performance Analysis
CADM: Confusion Model-based Detection Method for Real-drift in Chunk Data Stream
Hu, Songqiao, Liu, Zeyi, He, Xiao
Concept drift detection has attracted considerable attention due to its importance in many real-world applications such as health monitoring and fault diagnosis. Conventionally, most advanced approaches will be of poor performance when the evaluation criteria of the environment has changed (i.e. concept drift), either can only detect and adapt to virtual drift. In this paper, we propose a new approach to detect real-drift in the chunk data stream with limited annotations based on concept confusion. When a new data chunk arrives, we use both real labels and pseudo labels to update the model after prediction and drift detection. In this context, the model will be confused and yields prediction difference once drift occurs. We then adopt cosine similarity to measure the difference. And an adaptive threshold method is proposed to find the abnormal value. Experiments show that our method has a low false alarm rate and false negative rate with the utilization of different classifiers.
FairGAT: Fairness-aware Graph Attention Networks
Graphs can facilitate modeling various complex systems such as gene networks and power grids, as well as analyzing the underlying relations within them. Learning over graphs has recently attracted increasing attention, particularly graph neural network-based (GNN) solutions, among which graph attention networks (GATs) have become one of the most widely utilized neural network structures for graph-based tasks. Although it is shown that the use of graph structures in learning results in the amplification of algorithmic bias, the influence of the attention design in GATs on algorithmic bias has not been investigated. Motivated by this, the present study first carries out a theoretical analysis in order to demonstrate the sources of algorithmic bias in GAT-based learning for node classification. Then, a novel algorithm, FairGAT, that leverages a fairness-aware attention design is developed based on the theoretical findings. Experimental results on real-world networks demonstrate that FairGAT improves group fairness measures while also providing comparable utility to the fairness-aware baselines for node classification and link prediction.
Machine Guided Discovery of Novel Carbon Capture Solvents
McDonagh, James L., Wunsch, Benjamin H., Zavitsanou, Stamatia, Harrison, Alexander, Elmegreen, Bruce, Gifford, Stacey, van Kessel, Theodore, Cipcigan, Flaviu
The increasing importance of carbon capture technologies for deployment in remediating CO2 emissions, and thus the necessity to improve capture materials to allow scalability and efficiency, faces the challenge of materials development, which can require substantial costs and time. Machine learning offers a promising method for reducing the time and resource burdens of materials development through efficient correlation of structure-property relationships to allow down-selection and focusing on promising candidates. Towards demonstrating this, we have developed an end-to-end "discovery cycle" to select new aqueous amines compatible with the commercially viable acid gas scrubbing carbon capture. We combine a simple, rapid laboratory assay for CO2 absorption with a machine learning based molecular fingerprinting model approach. The prediction process shows 60% accuracy against experiment for both material parameters and 80% for a single parameter on an external test set. The discovery cycle determined several promising amines that were verified experimentally, and which had not been applied to carbon capture previously. In the process we have compiled a large, single-source data set for carbon capture amines and produced an open source machine learning tool for the identification of amine molecule candidates (https://github.com/IBM/Carbon-capture-fingerprint-generation).
Converging Measures and an Emergent Model: A Meta-Analysis of Human-Automation Trust Questionnaires
Razin, Yosef S., Feigh, Karen M.
A significant challenge to measuring human-automation trust is the amount of construct proliferation, models, and questionnaires with highly variable validation. However, all agree that trust is a crucial element of technological acceptance, continued usage, fluency, and teamwork. Herein, we synthesize a consensus model for trust in human-automation interaction by performing a meta-analysis of validated and reliable trust survey instruments. To accomplish this objective, this work identifies the most frequently cited and best-validated human-automation and human-robot trust questionnaires, as well as the most well-established factors, which form the dimensions and antecedents of such trust. To reduce both confusion and construct proliferation, we provide a detailed mapping of terminology between questionnaires. Furthermore, we perform a meta-analysis of the regression models that emerged from those experiments which used multi-factorial survey instruments. Based on this meta-analysis, we demonstrate a convergent experimentally validated model of human-automation trust. This convergent model establishes an integrated framework for future research. It identifies the current boundaries of trust measurement and where further investigation is necessary. We close by discussing choosing and designing an appropriate trust survey instrument. By comparing, mapping, and analyzing well-constructed trust survey instruments, a consensus structure of trust in human-automation interaction is identified. Doing so discloses a more complete basis for measuring trust emerges that is widely applicable. It integrates the academic idea of trust with the colloquial, common-sense one. Given the increasingly recognized importance of trust, especially in human-automation interaction, this work leaves us better positioned to understand and measure it.
Utilizing Network Properties to Detect Erroneous Inputs
Gorbett, Matt, Blanchard, Nathaniel
Neural networks are vulnerable to a wide range of erroneous inputs such as adversarial, corrupted, out-of-distribution, and misclassified examples. In this work, we train a linear SVM classifier to detect these four types of erroneous data using hidden and softmax feature vectors of pre-trained neural networks. Our results indicate that these faulty data types generally exhibit linearly separable activation properties from correct examples, giving us the ability to reject bad inputs with no extra training or overhead. We experimentally validate our findings across a diverse range of datasets, domains, pre-trained models, and adversarial attacks.
Sequential Knockoffs for Variable Selection in Reinforcement Learning
Ma, Tao, Cai, Hengrui, Qi, Zhengling, Shi, Chengchun, Laber, Eric B.
Interest in reinforcement learning (RL, Sutton & Barto 2018) has increased dramatically in recent years due in part to a number of high-profile successes in games (Mnih et al. 2013, 2015), autonomous driving (Sallab et al. 2017), and precision medicine (Tsiatis et al. 2019). However, despite theoretical and computational advances, real-world application of RL remains difficult. A primary challenge is dealing with high-dimensional state representations. Such representations occur naturally in systems with high-dimensional measurements, like images or audio, but can also occur when the system state is constructed by concatenating a series of measurements over a contiguous block of time. A high-dimensional state-- when a more parsimonious one would suffice--dilutes the efficiency of learning algorithms and makes the estimated optimal policy harder to interpret. Thus, methods for removing uninformative or redundant variables from the state are of tremendous practical value. We develop a general variable selection algorithm for offline RL, which aims to learn an optimal policy using only logged data, i.e., without any additional online interaction. Our contributions can be summarized as follows: (i) we formally define a minimal sufficient state for an MDP and argue that it is an appropriate target by which to design and evaluate variable selection methods in RL; (ii) we show that naïve variable selection methods based on the state or reward alone need not recover the minimal sufficient state; (iii) we propose a novel sequential knockoffs (SEEK) algorithm that applies with general black-box learning methods, and, under a β-mixing condition, consistently recovers the minimal sufficient state, and controls the false discovery rate (FDR, the ratio of the number of selected irrelevant variables to the number of selected variables); and (iv) we develop a novel algorithm to estimate the β-mixing coefficients of an MDP. The algorithm in (iv) is important in its own right as it applies to a number of applications beyond RL (McDonald et al. 2015).
Detecting Backdoors in Pre-trained Encoders
Feng, Shiwei, Tao, Guanhong, Cheng, Siyuan, Shen, Guangyu, Xu, Xiangzhe, Liu, Yingqi, Zhang, Kaiyuan, Ma, Shiqing, Zhang, Xiangyu
Self-supervised learning in computer vision trains on unlabeled data, such as images or (image, text) pairs, to obtain an image encoder that learns high-quality embeddings for input data. Emerging backdoor attacks towards encoders expose crucial vulnerabilities of self-supervised learning, since downstream classifiers (even further trained on clean data) may inherit backdoor behaviors from encoders. Existing backdoor detection methods mainly focus on supervised learning settings and cannot handle pre-trained encoders especially when input labels are not available. In this paper, we propose DECREE, the first backdoor detection approach for pre-trained encoders, requiring neither classifier headers nor input labels. We evaluate DECREE on over 400 encoders trojaned under 3 paradigms. We show the effectiveness of our method on image encoders pre-trained on ImageNet and OpenAI's CLIP 400 million image-text pairs. Our method consistently has a high detection accuracy even if we have only limited or no access to the pre-training dataset.
A Case Study on AI Engineering Practices: Developing an Autonomous Stock Trading System
Today, many systems use artificial intelligence (AI) to solve complex problems. While this often increases system effectiveness, developing a production-ready AI-based system is a difficult task. Thus, solid AI engineering practices are required to ensure the quality of the resulting system and to improve the development process. While several practices have already been proposed for the development of AI-based systems, detailed practical experiences of applying these practices are rare. In this paper, we aim to address this gap by collecting such experiences during a case study, namely the development of an autonomous stock trading system that uses machine learning functionality to invest in stocks. We selected 10 AI engineering practices from the literature and systematically applied them during development, with the goal to collect evidence about their applicability and effectiveness. Using structured field notes, we documented our experiences. Furthermore, we also used field notes to document challenges that occurred during the development, and the solutions we applied to overcome them. Afterwards, we analyzed the collected field notes, and evaluated how each practice improved the development. Lastly, we compared our evidence with existing literature. Most applied practices improved our system, albeit to varying extent, and we were able to overcome all major challenges. The qualitative results provide detailed accounts about 10 AI engineering practices, as well as challenges and solutions associated with such a project. Our experiences therefore enrich the emerging body of evidence in this field, which may be especially helpful for practitioner teams new to AI engineering.
Artificial-intelligence-based molecular classification of diffuse gliomas using rapid, label-free optical imaging
Hollon, Todd C., Jiang, Cheng, Chowdury, Asadur, Nasir-Moin, Mustafa, Kondepudi, Akhil, Aabedi, Alexander, Adapa, Arjun, Al-Holou, Wajd, Heth, Jason, Sagher, Oren, Lowenstein, Pedro, Castro, Maria, Wadiura, Lisa Irina, Widhalm, Georg, Neuschmelting, Volker, Reinecke, David, von Spreckelsen, Niklas, Berger, Mitchel S., Hervey-Jumper, Shawn L., Golfinos, John G., Snuderl, Matija, Camelo-Piragua, Sandra, Freudiger, Christian, Lee, Honglak, Orringer, Daniel A.
Molecular classification has transformed the management of brain tumors by enabling more accurate prognostication and personalized treatment. However, timely molecular diagnostic testing for patients with brain tumors is limited, complicating surgical and adjuvant treatment and obstructing clinical trial enrollment. In this study, we developed DeepGlioma, a rapid ($< 90$ seconds), artificial-intelligence-based diagnostic screening system to streamline the molecular diagnosis of diffuse gliomas. DeepGlioma is trained using a multimodal dataset that includes stimulated Raman histology (SRH); a rapid, label-free, non-consumptive, optical imaging method; and large-scale, public genomic data. In a prospective, multicenter, international testing cohort of patients with diffuse glioma ($n=153$) who underwent real-time SRH imaging, we demonstrate that DeepGlioma can predict the molecular alterations used by the World Health Organization to define the adult-type diffuse glioma taxonomy (IDH mutation, 1p19q co-deletion and ATRX mutation), achieving a mean molecular classification accuracy of $93.3\pm 1.6\%$. Our results represent how artificial intelligence and optical histology can be used to provide a rapid and scalable adjunct to wet lab methods for the molecular screening of patients with diffuse glioma.
Discriminating Between Similar Nordic Languages
Automatic language identification is a challenging problem. Discriminating between closely related languages is especially difficult. This paper presents a machine learning approach for automatic language identification for the Nordic languages, which often suffer miscategorisation by existing state-of-the-art tools. Concretely we will focus on discrimination between six Nordic languages: Danish, Swedish, Norwegian (Nynorsk), Norwegian (Bokm{\aa}l), Faroese and Icelandic.