NSF Award: Using NLP to Identify Suspicious Transactions in Omnichannel Online C2C Marketplaces

Baylor University has been awarded funding under the SaTC program for Enabling Interdisciplinary Collaboration; a grant led by Principal Investigator Dr. Pablo Rivas and an amazing group of multidisciplinary researchers formed by:

  • Dr. Gissella Bichler from California State University San Bernardino, Center for Criminal Justice Research, School of Criminology and Criminal Justice.
  • Dr. Tomas Cerny is at Baylor University in the Computer Science Department, leading software engineering research.
  • Dr. Laurie Giddens from the University of North Texas, a faculty member at the G. Brint Ryan College of Business.
  • Dr. Stacy Petter is at Wake Forest University in the School of Business. She and Dr. Giddens have extensive research and funding in human trafficking research.
  • Dr. Javier Turek, a Research Scientist in Machine Learning at Intel Labs, is our collaborator in matters related to machine learning for natural language processing.

We also have two Ph.D. students working on this project: Alejandro Rodriguez and Korn Sooksatra.

This project was motivated by the increasing pattern of people buying and selling goods and services directly from other people via online marketplaces. While many online marketplaces enable transactions among reputable buyers and sellers, some platforms are vulnerable to suspicious transactions. This project investigates whether it is possible to automate the detection of illegal goods or services within online marketplaces. First, the project team will analyze the text of online advertisements and marketplace policies to identify indicators of suspicious activity. Then, the team will adapt the findings to a specific context to locate stolen motor vehicle parts advertised via online marketplaces. Together, the work will lead to general ways to identify signals of illegal online sales that can be used to help people choose trustworthy marketplaces and avoid illicit actors. This project will also provide law enforcement agencies and online marketplaces with insights to gather evidence on illicit goods or services on those marketplaces.

This research assesses the feasibility of modeling illegal activity in online consumer-to-consumer (C2C) platforms, using platform characteristics, seller profiles, and advertisements to prioritize investigations using actionable intelligence extracted from open-source information. The project is organized around three main steps. First, the research team will combine knowledge from computer science, criminology, and information systems to analyze online marketplace technology platform policies and identify platform features, policies, and terms of service that make platforms more vulnerable to criminal activity. Second, building on the understanding of platform vulnerabilities developed in the first step, the researchers will generate and train deep learning-based language models to detect illicit online commerce. Finally, to assess the generalizability of the identified markers, the investigators will apply the models to markets for motor vehicle parts, a licit marketplace that sometimes includes sellers offering stolen goods. This project establishes a cross-disciplinary partnership among a diverse group of researchers from different institutions and academic disciplines with collaborators from law enforcement and industry to develop practical, actionable insights.

Self-supervised modeling. After providing a corpus associated with a C2C domain of interest and ontologies, we will extract features followed by attention mechanisms for self-supervised and supervised tasks. The self-supervised models include the completion of missing information and domain-specific text encoding for learning representations. Then supervised tasks will leverage these representations to learn the relationships with targets.

Dr. Bejarano’s work is Recognized by Amazon

According to the World Federation of the Deaf, more than 70 million deaf people exist worldwide. More than 80% of them live in developing countries. Recent research by Dr. Gissella Bejarano, our very own postdoctoral research scientist, has been recognized for its impact on computer vision and speech recognition, providing opportunities to help individuals with disabilities. With support from AWS, Dr. Bejarano is finding better ways to translate Peruvian Sign Language using computer vision and natural language processing.

Read more about this in this release by AWS.

SICEM: A Sensitivity-Inspired Constrained Evaluation Method for Adversarial Attacks on Classifiers with Occluded Input Data

In the rapidly evolving field of artificial intelligence, understanding the sensitivity of models to adversarial attacks is crucial. In our recent paper, Korn Sooksatra introduces the Sensitivity-inspired constrained evaluation method (SICEM) to address this concern.

Sooksatra, K., Rivas, P. Evaluation of adversarial attacks sensitivity of classifiers with occluded input data. Neural Comput & Applic 34, 17615–17632 (2022). https://doi.org/10.1007/s00521-022-07387-y

Understanding SICEM

Our proposed method, SICEM, evaluates the vulnerability of an incomplete input against an adversarial attack in comparison to a complete one. This is achieved by leveraging the Jacobian matrix concept. The sensitivity of the target classifier’s output to each attribute of the input is calculated, providing a comprehensive understanding of how changes in the input can affect the output.

    \[ s(x,y)_i =  \left|\min \left(0, \frac{\partial Z(x)_y}{\partial x_i} \cdot \left(\sum_{y^{'} \neq y} \frac{\partial Z(x)_{y^{'}}}{\partial x_i}\right) \cdot C(y, 1, 0)_i\right)\right| \]

This sensitivity score gives us an insight into how much each attribute of the input contributes to the output’s sensitivity. The score is then used to estimate the overall sensitivity of the given input and its mask.

    \[ S(x, M)_y = \sum_{i=0}^{n-1} (s(x, y)_i \cdot M_i) \]

For a complete input, the sensitivity ratio provides a comparative measure of how sensitive the classifier’s output is for an incomplete input versus a complete one.

Results and Implications

Our focus was on an automobile image from the CIFAR-10 dataset. Interestingly, adversarial examples generated by FGSM and IGSM required the same value of \epsilon, which was significantly lower than for other images. This can be attributed to the layer-wise linearity of the classifier. Larger inputs, like the automobile image, require a smaller \epsilon to create an adversarial example. However, JSMA required a higher \epsilon due to the metric of L_0 norm.

Understanding the sensitivity of AI models is paramount in ensuring their robustness against adversarial attacks. The SICEM method provides a comprehensive tool to ensure safer and more reliable AI systems. Read the full paper here [ bib |  .pdf ].

Hybrid Quantum Variational Autoencoders for Representation Learning

One of our recent papers introduces a novel hybrid quantum machine learning approach to unsupervised representation learning by using a quantum variational circuit that is trainable with traditional gradient descent techniques. Access it here: [ bib | .pdf ]

Much of the work related to quantum machine learning has been popularized in recent years. Some of the most notable efforts involve variational approaches (Cerezo 2021, Khoshaman 2018, Yuan 2019). Researchers have shown that these models are effective in complex tasks that grant further studies and open new doors for applied quantum machine learning research. Another popular approach is to perform kernel learning using a quantum approach (Blank 2020, Schuld 2019, Rebentrost 2014). In this case the kernel-based projection of data \mathbf{x} produces a easible linear mapping to the desired target y as follows:

(1)   \begin{equation*}     y(\mathbf{x})=\operatorname{sign}\left(\sum_{j=1}^{M} \alpha_{j} k\left(\mathbf{x}_{j}, \mathbf{x}\right)+b\right) \end{equation*}

for hyper parameters b,\alpha that need to be provided or learned. This enables the creation of some types of support vector machines whose kernels are calculated such that the data \mathbf{x} is processed in the quantum realm. That is \left|\mathbf{x}_{j}\right\rangle=1 /\left|\mathbf{x}_{j}\right| \sum_{k=1}^{N}\left(\mathbf{x}_{j}\right)_{k}|k\rangle. The work of Schuld et al., expands the theory behind this idea an show that all kernel methods can be quantum machine learning methods. Recently, in 2020, Mari et al., worked on variational models that are hybrid in format. Particularly, the authors focused on transfer learning, i.e., the idea of bringing a pre-trained model (or a piece of it) to be part of another model. In the case of Mari the larger model is a computer vision model, e.g., ResNet, which is part of a variational quantum circuit that performs classification. The work we present here follows a similar idea, but we focus in the autoencoder architecture, rather than a classification model, and we focus on learning representations in comparison between a classic and a variational quantum fine-tuned model.

Evaluating Accuracy and Adversarial Robustness of Quanvolutional Neural Networks

A combination of a quantum circuit and a convolutional neural network (CNN) can have better results over a classic CNN in some cases. In our recent article, we show an example of such a case, using accuracy and adversarial examples as measures of performance and robustness. Check it out: [ bib | pdf ]

Artificial Intelligence Computing at the Quantum Level

A unique feature of a quantum computer in comparison to a classical computer is that the bit (often referred to as qubit can be in one of two states (0 or 1) and possibly a superposition of the two states (a linear combination of 0 and 1) per time. The most common mathematical representation of a qubit is

    \[ |{\psi\rangle} = \alpha|{0\rangle} + \beta|{1\rangle},  \]

which denotes a superposition state, where \alpha, \beta are complex numbers and |{0\rangle}, |{1\rangle} are computational basis states that form an orthonormal basis in this vector space.

To know more about how quantum machine learning takes advantage of this, check our newest article here.

Enhancing Adversarial Examples on Deep QNetworks with Previous Information

This work finds strong adversarial examples for Deep Q Networks which are famous deep reinforcement learning models. We combine two subproblems of finding adversarial examples in deep reinforcement learning: finding states to perturb and determining how much to perturb. Therefore, the attack can jointly optimize this problem. Further, we trained Deep Q Networks to play Atari games: Breakout and Space Invader. Then, we used our attack to find adversarial examples on those games. As a result, we can achieve state-of-the-art results and showed that our attack is natural and stealthy. Paper: [ bib | pdf ]

Performance Analysis of Quantum Machine Learning Classifiers

Quantum mechanics has advanced analytical studies beyond the constraints of classical mechanics in recent years. Quantum Machine Learning  (QML) is one of these fields of study. QML currently offers working solutions comparable to (traditional) machine learning, such as classification and prediction tasks utilizing quantum classifiers (q-classifiers).

We investigated a variety of these q-classifiers and reported the outcomes of our research in comparison to their classical counterparts. Paper: [ bib | .pdf ]

NSF Award: Center for Standards and Ethics in Artificial Intelligence (CSEAI)

IUCRC Planning Grant

Baylor University has been awarded an Industry-University Cooperative Research Centers planning grant led by Principal Investigator Dr. Pablo Rivas.

The last twenty years have seen an unprecedented growth of AI-enabled technologies in practically every industry. More recently, an emphasis has been placed on ensuring industry and government agencies that use or produce AI-enabled technology have a social responsibility to protect consumers and increase trustworthiness in products and services. As a result, regulatory groups are producing standards for artificial intelligence (AI) ethics worldwide. The Center for Standards and Ethics in Artificial Intelligence (CSEAI) aims to provide industry and government the necessary resources for adopting and efficiently implementing standards and ethical practices in AI through research, outreach, and education.

CSEAI’s mission is to work closely with industry and government research partners to study AI protocols, procedures, and technologies that enable the design, implementation, and adoption of safe, effective, and ethical AI standards. The varied AI skillsets of CSEAI faculty enable the center to address various fundamental research challenges associated with the responsible, equitable, traceable, reliable, and governable development of AI-fueled technologies. The site at Baylor University supports research areas that include bias mitigation through variational deep learning; assessment of products’ sensitivity to AI-guided adversarial attacks; and fairness evaluation metrics.

The CSEAI will help industry and government organizations that use or produce AI technology to provide standardized, ethical products safe for consumers and users, helping the public regain trust and confidence in AI technology. The center will recruit, train, and mentor undergraduates, graduate students, and postdocs from diverse backgrounds, motivating them to pursue careers in AI ethics and producing a diverse workforce trained in standardized and ethical AI. The center will release specific ethics assessment tools, and AI best practices will be licensed or made available to various stakeholders through publications, conference presentations, and the CSEAI summer school.

Both a publicly accessible repository and a secured members-only repository (comprising meeting materials, workshop information, research topics and details, publications, etc.) will be maintained either on-site at Baylor University and/or on a government/DoD-approved cloud service. A single public and secured repository will be used for CSEAI, where permissible, to facilitate continuity of efforts and information between the different sites. This repository will be accessible at a publicly listed URL at Baylor University, https://cseai.center, for the lifetime of the center and moved to an archiving service once no longer maintained.

Lead Institutions

The CSEAI is partnering with Rutgers University, directed by Dr. Jorge Ortiz, and the University of Miami, directed by Dr. Daniel Diaz. The Industry Liaison Officer is Laura Montoya, a well-known industry leader, AI ethics advocate, and entrepreneur.

The three institutions account for a large number of skills that form a unique center that functions as a whole. Every faculty member at every institution brings a unique perspective to the CSEAI.

Baylor Co-PIs: Academic Leadership Team

The Lead site at Baylor is composed of four faculty that serve at different levels, having Dr. Robert Marks as the faculty lead in the Academic Leadership Team, working closely with PI Rivas in project execution and research strategic planning. Dr. Greg Hamerly and Dr. Liang Dong strengthen and diversify the general ML research and application areas, while Dr. Tomas Cerny expands research capability to the software engineering realm.


Dr. Pamela Harper from Marist College has been a long-lasting collaborator of PI Rivas in matters of business and management ethics and is a collaborator of the CSEAI in those areas. On the other hand, Patricia Shaw is a lawyer and an international advisor on tech ethics policy, governance, and regulation. She works with PI Rivas in developing the AI Ethics Standard IEEE P7003 (algorithmic bias).

Workforce Development Plan

The CSEAI is planning to develop the workforce in many different avenues that include both undergraduate and graduate student research mentoring as well as industry professionals continuing education through specialized training and ad-hoc certificates.

On the Performance of Convolutional Neural Networks Initialized with Gabor Filters

When observing a fully trained CNN, researchers have found that the pattern on the kernel filters (convolution window) of the receptive convolutional layer closely resembles the Gabor filters. Gabor filters have existed for a long time, and researchers have been using them for texture analysis. Given the nature and purpose of the receptive layer of CNN, Gabor filters could act as a suitable replacement strategy for the randomly initialized kernels of the receptive layer in CNN, which could potentially boost the performance without any regard to the nature of the dataset. The findings in this thesis show that when low-level kernel filters are initialized with Gabor filters, there is a boost in accuracy, Area Under ROC (Receiver Operating Characteristic) Curve (AUC), minimum loss, and speed in some cases based on the complexity of the dataset. [pdf, bib]

Different Gabor filters with different values for \lambda, \theta, and \gamma. Different parameters will change filter properties.