Gradient vector fields of discrete morse functions and watershed-cuts
In Proceedings of the IAPR international conference on discrete geometry and mathematical morphology (DGMM)
Residual 3D U-net with localization for brain tumor segmentation
In International MICCAI brainlesion workshop
Abstract
AGAT: Building and evaluating binary partition trees for image segmentation
In SoftwareX
Abstract
AGAT is a Java library dedicated to the construction, handling and evaluation of binary partition trees, a hierarchical data structure providing multiscale partitioning of images and, more generally, of valued graphs. On the one hand, this library offers functionalities to build binary partition trees in the usual way, but also to define multifeature trees, a novel and richer paradigm of binary partition trees built from multiple images and/or several criteria. On the other hand, it also allows one to manipulate the binary partition trees, for instance by defining/computing tree cuts that can be interpreted in particular as segmentations when dealing with image modeling. In addition, some evaluation tools are also provided, which allow one to evaluate the quality of different binary partition trees for such segmentation tasks. AGAT can be easily handled by various kinds of users (students, researchers, practitioners). It can be used as is for experimental purposes, but can also form a basis for the development of new methods and paradigms for construction, use and intensive evaluation of binary partition trees. Beyond the usual imaging applications, its underlying structure also allows for more general developments in graph-based analysis, leading to a wide range of potential applications in computer vision, image/data analysis and machine learning.
Introducing the boundary-aware loss for deep image segmentation
In Proceedings of the 32nd british machine vision conference (BMVC)
Abstract
Most contemporary supervised image segmentation methods do not preserve the initial topology of the given input (like the closeness of the contours). One can generally remark that edge points have been inserted or removed when the binary prediction and the ground truth are compared. This can be critical when accurate localization of multiple interconnected objects is required. In this paper, we present a new loss function, called, Boundary-Aware loss (BALoss), based on the Minimum Barrier Distance (MBD) cut algorithm. It is able to locate what we call the leakage pixels and to encode the boundary information coming from the given ground truth. Thanks to this adapted loss, we are able to significantly refine the quality of the predicted boundaries during the learning procedure. Furthermore, our loss function is differentiable and can be applied to any kind of neural network used in image processing. We apply this loss function on the standard U-Net and DC U-Net on Electron Microscopy datasets. They are well-known to be challenging due to their high noise level and to the close or even connected objects covering the image space. Our segmentation performance, in terms of Variation of Information (VOI) and Adapted Rank Index (ARI), are very promising and lead to $\approx{}15%$ better scores of VOI and $\approx{}5%$ better scores of ARI than the state-of-the-art. The code of boundary-awareness loss is freely available at https://github.com/onvungocminh/MBD_BAL
Strong Euler wellcomposedness
In Journal of Combinatorial Optimization
Abstract
In this paper, we define a new flavour of well-composedness, called strong Euler well-composedness. In the general setting of regular cell complexes, a regular cell complex of dimension $n$ is strongly Euler well-composed if the Euler characteristic of the link of each boundary cell is $1$, which is the Euler characteristic of an $(n-1)$-dimensional ball. Working in the particular setting of cubical complexes canonically associated with $n$-D pictures, we formally prove in this paper that strong Euler well-composedness implies digital well-composedness in any dimension $n\geq 2$ and that the converse is not true when $n\geq 4$.
Continuous well-composedness implies digital well-composedness in $n$-D
In Journal of Mathematical Imaging and Vision
Abstract
In this paper, we prove that when a $n$-D cubical set is continuously well-composed (CWC), that is, when the boundary of its continuous analog is a topological $(n-1)$-manifold, then it is digitally well-composed (DWC), which means that it does not contain any critical configuration. We prove this result thanks to local homology. This paper is the sequel of a previous paper where we proved that DWCness does not imply CWCness in 4D.
Automation of binary analysis: From open source collection to threat intelligence
In Proceedings of the 28th c&ESAR
Abstract
Many open sources of binaries, including malware, have emerged in the landscape in recent years. Their quality compares very favourably with commercial sources, as emphasised by Thibaud Binetruy (Twitter influencer under a pseudonym, Société Générale CERT, 2020): “Integrating operational threat intelin your defense mechanisms doesn’t mean buying Threat Intel. You can start by using the [mass] of open source indicators available for free.” Some are provided by official sources (Abuse.ch, with data supplied by the Swiss national CERT, among others), while others are made available in more obscure ways, sometimes anonymously (VirusShare, VX-Underground, etc.). Our examination of these sources underlines the wide disparity in quality and quantity between them. We have had to take this diversity into account in our research, designing a dedicated platform that enables us to supply information to our binary analysis products and to conduct daily analyses of correlations between and within malware families on a large scale. This work can then be applied to concrete cases such as Babuk, Ryuk and Conti. We have been able to highlight links for these families by immediately identifying correlations, with additional manual analysis then confirming the genealogy of the samples precisely.
A secure blockchain-based architecture for the COVID-19 data network
In 2021 5th cyber security in networking conference (CSNet)
Abstract
The COVID-19 pandemic has impacted the world economy and mainly all activities where social distancing cannot be respected. In order to control this pandemic, screening tests such as PCR have become essential. For example, in the case of a trip, the traveler must carry out a PCR test within 72 hours before his departure and if he is not a carrier of the COVID-19, he can therefore travel by presenting, during check-in and boarding, the negative result sheet to the agent. The latter will then verify the presented sheet by trusting: (a) the medical biology laboratory, (b) the credibility of the traveler for not having changed the PCR result from “positive to negative”. Therefore, this confidence and this verification are made without being based on any mechanism of security and integrity, despite the great importance of the PCR test results to control the COVID-19 pandemic. Consequently, we propose in this paper a blockchain-based decentralized trust architecture that aims to guarantee the integrity, immutability and traceability of COVID-19 test results. Our proposal also aims to ensure the interconnection between several organizations (airports, medical laboratories, cinemas, etc.) in order to access COVID-19 test results in a secure and decentralized manner.
Evaluation of anomaly detection for cybersecurity using inductive node embedding with convolutional graph neural networks
In Complex network 2021
Abstract
In the face of continuous cyberattacks, many scientists have proposed machine learning-based network anomaly detection methods. While deep learning effectively captures unseen patterns of Euclidean data, there is a huge number of applications where data are described in the form of graphs. Graph analysis have improved detecting anomalies in non-Euclidean domains, but it suffered from high computational cost. Graph embeddings have solved this problem by converting each node in the network into low dimensional representation, but it lacks the ability to generalize to unseen nodes. Graph convolution neural network methods solve this problem through inductive node embedding (inductive GNN). Inductive GNN shows better performance in detecting anomalies with less complexity than graph analysis and graph embedding methods.
VizNN: Visual data augmentation with convolutional neural networks for cybersecurity investigation
In Upper-rhine artificial intelligence symposium
Abstract
One of the key challenges of Security Operating Centers (SOCs) is to provide rich information to the security analyst to ease the investigation phase in front of a cyberattack. This requires the combination of supervision with detection capabilities. Supervision enables the security analysts to gain an overview on the security state of the information system under protection. Detection uses advanced algorithms to extract suspicious events from the huge amount of traces produced by the system. To enable coupling an efficient supervision with performance detection, the use of visualisation-based analysis is a appealing approach, which into the bargain provides an elegant solution for data augmentation and thus improved detection performance. We propose VizNN, a Convolutional Neural Networks for analysing trace features through their graphical representation. VizNN enables to gain a visual overview of the traces of interests, and Convolutional Neural Networks leverage a scalability capability. An evaluation of the proposed scheme is performed against reference classifiers for detecting attacks, XGBoost and Random Forests