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Zorello, Ligia Maria Moreira (author), Bliek, Laurens (author), Troia, Sebastian (author), Maier, Guido (author), Verwer, S.E. (author)In the context of the ever-evolving 5G landscape, where network management and control are paramount, a new Radio Access Network (RAN) as emerged. This innovative RAN offers a revolutionary approach by enabling the flexible distribution of baseband functions across various nodes, all tailored to meet the ever-shifting demands of both system...journal article 2024
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Baumgartner, R. (author), Verwer, S.E. (author)State machines models are models that simulate the behavior of discrete event systems, capable of representing systems such as software systems, network interactions, and control systems, and have been researched extensively. The nature of most learning algorithms however is the assumption that all data be available at the begining of the...conference paper 2023
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Nadeem, A. (author), Vos, D.A. (author), Cao, C.S. (author), Pajola, Luca (author), Dieck, S. (author), Baumgartner, R. (author), Verwer, S.E. (author)Explainable Artificial Intelligence (XAI) aims to improve the transparency of machine learning (ML) pipelines. We systematize the increasingly growing (but fragmented) microcosm of studies that develop and utilize XAI methods for defensive and offensive cybersecurity tasks. We identify 3 cybersecurity stakeholders, i.e., model users, designers,...conference paper 2023
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Vos, D.A. (author), Verwer, S.E. (author)Interpretability of reinforcement learning policies is essential for many real-world tasks but learning such interpretable policies is a hard problem. Particularly, rule-based policies such as decision trees and rules lists are difficult to optimize due to their non-differentiability. While existing techniques can learn verifiable decision...conference paper 2023
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Bliek, Laurens (author), Guijt, A. (author), Karlsson, R.K.A. (author), Verwer, S.E. (author), de Weerdt, M.M. (author)Surrogate algorithms such as Bayesian optimisation are especially designed for black-box optimisation problems with expensive objectives, such as hyperparameter tuning or simulation-based optimisation. In the literature, these algorithms are usually evaluated with synthetic benchmarks which are well established but have no expensive objective...journal article 2023
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Zhang, Yingqian (author), Bliek, Laurens (author), da Costa, Paulo (author), Refaei Afshar, Reza (author), Reijnen, Robbert (author), Catshoek, T. (author), Vos, D.A. (author), Verwer, S.E. (author), Schmitt-Ulms, Fynn (author)This paper reports on the first international competition on AI for the traveling salesman problem (TSP) at the International Joint Conference on Artificial Intelligence 2021 (IJCAI-21). The TSP is one of the classical combinatorial optimization problems, with many variants inspired by real-world applications. This first competition asked the...journal article 2023
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Vos, D.A. (author), Verwer, S.E. (author)Decision trees are popular models for their interpretation properties and their success in ensemble models for structured data. However, common decision tree learning algorithms produce models that suffer from adversarial examples. Recent work on robust decision tree learning mitigates this issue by taking adversarial perturbations into...conference paper 2023
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Nadeem, A. (author), Verwer, S.E. (author), Yang, Shanchieh Jay (author)The evolving nature of the tactics, techniques, and procedures used by cyber adversaries have made signature and template based methods of modeling adversary behavior almost infeasible. We are moving into an era of data-driven autonomous cyber defense agents that learn contextually meaningful adversary behaviors from observables. In this chapter...book chapter 2023
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Nadeem, A. (author), Verwer, S.E. (author)Sequence clustering in a streaming environment is challenging because it is computationally expensive, and the sequences may evolve over time. K-medoids or Partitioning Around Medoids (PAM) is commonly used to cluster sequences since it supports alignment-based distances, and the k-centers being actual data items helps with cluster...conference paper 2023
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Zorello, Ligia Maria Moreira (author), Bliek, L. (author), Troia, Sebastian (author), Guns, Tias (author), Verwer, S.E. (author), Maier, Guido (author)The 5G Radio Access Network (RAN) virtualization aims to improve network quality and lower the operator's costs. One of its main features is the functional split, i.e., dividing the instantiation of RAN baseband functions into different units over metro-network nodes. However, its optimal placement is non-trivial: it depends on the...journal article 2022
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Cao, C.S. (author), Blaise, Agathe (author), Verwer, S.E. (author), Rebecchi, Filippo (author)These days more companies are shifting towards using cloud environments to provide their services to their client. While it is easy to set up a cloud environment, it is equally important to monitor the system's runtime behaviour and identify anomalous behaviours that occur during its operation. In recent years, the utilisation of Recurrent...conference paper 2022
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Nadeem, A. (author), Verwer, S.E. (author), Moskal, Stephen (author), Yang, Shanchieh Jay (author)Ideal cyber threat intelligence (CTI) includes insights into attacker strategies that are specific to a network under observation. Such CTI currently requires extensive expert input for obtaining, assessing, and correlating system vulnerabilities into a graphical representation, often referred to as an attack graph (AG). Instead of deriving AGs...journal article 2022
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Nadeem, A. (author), Rimmer, Vera (author), Wouter, Joosen (author), Verwer, S.E. (author)With rapidly evolving threat landscape surrounding malware, intelligent defenses based on machine learning are paramount. In this chapter, we review the literature proposed in the past decade and identify the state-of-the-art in various related research directions—malware detection, malware analysis, adversarial malware, and malware author...book chapter 2022
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Rimmer, Vera (author), Nadeem, A. (author), Verwer, S.E. (author), Preuveneers, Davy (author), Joosen, Wouter (author)This chapter contributes to the ongoing discussion of strengthening security by applying AI techniques in the scope of intrusion detection. The focus is set on open-world detection of attacks through data-driven network traffic analysis. This research topic is complementary to the earlier chapter on intelligent malware detection. In this...book chapter 2022
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Vos, D.A. (author), Verwer, S.E. (author)Recently it has been shown that many machine learning models are vulnerable to adversarial examples: perturbed samples that trick the model into misclassifying them. Neural networks have received much attention but decision trees and their ensembles achieve state-of-the-art results on tabular data, motivating research on their robustness....conference paper 2021
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Ye, Qing Chuan (author), Rhuggenaath, Jason. S. (author), Zhang, Yingqian (author), Verwer, S.E. (author), Hilgeman, Michiel Jurgen (author)Designing auction parameters for online industrial auctions is a complex problem due to highly heterogeneous items. Currently, online auctioneers rely heavily on their experts in auction design. The ability of predicting how well an auction will perform prior to the start comes in handy for auctioneers. If an item is expected to be a low...journal article 2021
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Bliek, L. (author), Guijt, A. (author), Verwer, S.E. (author), de Weerdt, M.M. (author)A challenging problem in both engineering and computer science is that of minimising a function for which we have no mathematical formulation available, that is expensive to evaluate, and that contains continuous and integer variables, for example in automatic algorithm configuration. Surrogate-based algorithms are very suitable for this type...conference paper 2021
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Nadeem, A. (author), Verwer, S.E. (author), Moskal, Stephen (author), Yang, Shanchieh Jay (author)Attack graphs (AG) are a popular area of research that display all the paths an attacker can exploit to penetrate a network. Existing techniques for AG generation rely heavily on expert input regarding vulnerabilities and network topology. In this work, we advocate the use of AGs that are built directly using the actions observed through...conference paper 2021
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Nadeem, A. (author), Verwer, S.E. (author), Yang, Shanchieh Jay (author)Attack graphs (AG) are used to assess pathways availed by cyber adversaries to penetrate a network. State-of-the-art approaches for AG generation focus mostly on deriving dependencies between system vulnerabilities based on network scans and expert knowledge. In real-world operations however, it is costly and ineffective to rely on constant...conference paper 2021
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Karlsson, R.K.A. (author), Bliek, L. (author), Verwer, S.E. (author), de Weerdt, M.M. (author)One method to solve expensive black-box optimization problems is to use a surrogate model that approximates the objective based on previous observed evaluations. The surrogate, which is cheaper to evaluate, is optimized instead to find an approximate solution to the original problem. In the case of discrete problems, recent research has...conference paper 2021