References of "State, Radu 50003137"
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See detailBlockchain Governance: An Overview and Prediction of Optimal Strategies Using Nash Equilibrium
Khan, Nida UL; Ahmad, Tabrez; Patel, Anass et al

in 3rd AUE International Research Conference (in press)

Blockchain governance is a subject of ongoing research and an interdisciplinary view of blockchain governance is vital to aid in further research for establishing a formal governance framework for this ... [more ▼]

Blockchain governance is a subject of ongoing research and an interdisciplinary view of blockchain governance is vital to aid in further research for establishing a formal governance framework for this nascent technology. In this paper, the position of blockchain governance within the hierarchy of Institutional governance is discussed. Blockchain governance is analyzed from the perspective of IT governance using Nash equilibrium to predict the outcome of different governance decisions. A payoff matrix for blockchain governance is created and simulation of different strategy profiles is accomplished for computation of all Nash equilibria. We also create payoff matrices for different kinds of blockchain governance, which were used to propose novel mathematical formulae usable to predict the best governance strategy that minimizes the occurrence of a hard fork as well as predicts the behavior of the majority during protocol updates. [less ▲]

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See detailTowards Privacy Preserving Data Centric Super App
Carvalho Ota, Fernando Kaway UL; Meira, Jorge Augusto UL; Frank, Raphaël UL et al

in Carvalho Ota, Fernando Kaway; Meira, Jorge Augusto; Frank, Raphaël (Eds.) et al 2020 Mediterranean Communication and Computer Networking Conference, Arona 17-19 June 2020 (2020, September 10)

The number of smartphone users recently surpassed the numbers of desktop users on Internet, and opened up countless development challenges and business opportunities. Not only the fact that the majority ... [more ▼]

The number of smartphone users recently surpassed the numbers of desktop users on Internet, and opened up countless development challenges and business opportunities. Not only the fact that the majority of users are connected using their smartphones, but the number of Internet users in general has popularized the massive use of data-driven applications. In this context, the concept of super apps seems to be the next game-changer for the mobile apps industry, and the challenges related to security and privacy are key aspects for keeping user data safe. Thus, by combining different components for provisioning, authentication, membership and others, we propose a novel framework that enables the creation of a super app using privacy by design principles. [less ▲]

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See detailWorking with Deep Generative Models and Tabular Data Imputation
Camino, Ramiro Daniel UL; Hammerschmidt, Christian UL; State, Radu UL

Scientific Conference (2020, July 17)

Datasets with missing values are very common in industry applications. Missing data typically have a negative impact on machine learning models. With the rise of generative models in deep learning, recent ... [more ▼]

Datasets with missing values are very common in industry applications. Missing data typically have a negative impact on machine learning models. With the rise of generative models in deep learning, recent studies proposed solutions to the problem of imputing missing values based various deep generative models. Previous experiments with Generative Adversarial Networks (GANs) and Variational Autoencoders (VAEs) showed promising results in this domain. Initially, these results focused on imputation in image data, e.g. filling missing patches in images. Recent proposals addressed missing values in tabular data. For these data, the case for deep generative models seems to be less clear. In the process of providing a fair comparison of proposed methods, we uncover several issues when assessing the status quo: the use of under-specified and ambiguous dataset names, the large range of parameters and hyper-parameters to tune for each method, and the use of different metrics and evaluation methods. [less ▲]

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See detailThe rise of eBPF for non-intrusive performance monitoring
Cassagnes, Cyril UL; Trestioreanu, Lucian Andrei UL; Joly, Clement UL et al

in IEEE Xplore (2020, June 08)

In this paper, we explain that container engines are strengthening their isolation mechanisms. Therefore, nonintrusive monitoring becomes a must-have for the performance analysis of containerized user ... [more ▼]

In this paper, we explain that container engines are strengthening their isolation mechanisms. Therefore, nonintrusive monitoring becomes a must-have for the performance analysis of containerized user-space application in production environments. After a literature review and background of Linux subsystems and container isolation concepts, we present our lessons learned of using the extended Berkeley packet filter to monitor and profile performance. We carry out the profiling and tracing of several Interledger connectors using two full-fledged implementations of the Interledger protocol specifications. [less ▲]

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See detailTokenization of Sukuk: Ethereum Case Study
Khan, Nida UL; Kchouri, Bilal UL; Yatoo, Nissar Ahmad et al

in Global Finance Journal (2020)

Sukuk is a financial instrument that provides returns similar to conventional bonds. It has served to cater to the capital requirements of big corporations and governments, while circumventing interest to ... [more ▼]

Sukuk is a financial instrument that provides returns similar to conventional bonds. It has served to cater to the capital requirements of big corporations and governments, while circumventing interest to adhere to the Shariah law. Sukuk can be touted as Shariah-compliant bonds that rank amongst the most successful and the fastest growing financial instrument in the Islamic economy. The sukuk research area is marked by a dearth of quantitative literature, compared to qualitative academic work. This paper seeks to fill this existing gap, and introduces a novel, exploratory analysis of sukuk tokenization based on a case study. The funding needs of small and medium enterprises remains largely unmet through sukuk on account of the high costs involved, among other reasons. As we show in this paper, blockchains can aid to lower the cost incurred through the tokenization of sukuk. We highlight some of the key challenges involved in the issuance of sukuk and discuss their resolution using blockchain. We also provide a taxonomy of blockchain applications in finance, with a particular focus on Islamic finance. Our paper reviews different blockchain architectures to assess their viability for tokenization. We conduct a novel case study on sukuk tokenization by implementing a basic smart contract for Sukuk al-Murabaha on Ethereum. The paper concludes by a conceptual analysis of feasibility concerns, based on a comparison of the conducted cost-benefit analysis of conventional sukuk issuance with tokenization. [less ▲]

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See detailMobile App to SGX Enclave Secure Channel
Carvalho Ota, Fernando Kaway UL; Meira, Jorge Augusto UL; Cassagnes, Cyril UL et al

in 2019 IEEE International Symposium on Software Reliability Engineering Workshops (2020, February 13)

The current challenge for several applications is to guarantee the user’s privacy when using personal data. The broader problem is to transfer and process the data without exposing the sensitive content ... [more ▼]

The current challenge for several applications is to guarantee the user’s privacy when using personal data. The broader problem is to transfer and process the data without exposing the sensitive content to anyone, including the service provider(s). In this paper, we address this challenge by proposing a protocol to combine secure frameworks in order to exchange and process sensitive data, i.e. respecting user’s privacy. Our contribution is a protocol to perform a secure exchange of data between a mobile application and a trusted execution environment. In our experiments we show independent implementations of our protocol using three different encryption modes (i.e., CBC, ECB, GCM encryption). Our results support the feasibility and importance of an end-to-end secure channel protocol. [less ▲]

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See detailDeep dive into Interledger: Understanding the Interledger ecosystem - Part 4
Trestioreanu, Lucian Andrei UL; Cassagnes, Cyril UL; State, Radu UL

Learning material (2020)

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally ... [more ▼]

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally a protocol for interledger payments. To understand how is it possible to achieve this goal, several aspects of the technology require a deeper analysis. For this reason, in our journey to become knowledgeable and active contributor we decided to create our own test-bed on our premises. By doing so, we noticed that some aspects are well documented but we found that others might need more attention and clarification. Despite a large community effort, the task to keep information on a fast evolving software ecosystem is tedious and not always the priority for such a project. Therefore, the purpose of this document is to guide, through several hands-on activities, community members who want to engage at different levels. The document consolidates all the relevant information from generating a simple payment to ultimately create a test-bed with the Interledger protocol suite between Ripple and other distributed ledger technology. [less ▲]

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See detailBlockPGP: A Blockchain-based Framework for PGP Key Servers
Yakubov, Alexander UL; Shbair, Wazen UL; Khan, Nida UL et al

in International Journal of Networking and Computing (2020), 10(1), 1-24

Pretty Good Privacy (PGP) is one of the most prominent cryptographic standards offering end-to-end encryption for email messages and other sensitive information exchange. PGP allows to verify the identity ... [more ▼]

Pretty Good Privacy (PGP) is one of the most prominent cryptographic standards offering end-to-end encryption for email messages and other sensitive information exchange. PGP allows to verify the identity of the correspondent in information exchange as well as the information integrity. PGP implements asymmetric encryption with certificates shared through a network of PGP key servers. In this paper, we propose a new PGP management framework with the key servers infrastructure implemented using blockchain technology. Our approach offers fast propagation of certificate revocation among PGP key servers and elimination of man-in-the-middle risks. It also grants users the required access control to update their own PGP certificates, which is not the case with the current PGP key servers. A prototype has been implemented using Ethereum blockchain and an open source key server, named Hockeypuck. Finally, we evaluated the prototype with extensive experiments. Our results show that our solution is practical and it could be integrated with the existing public PGP key servers infrastructure. [less ▲]

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See detailTowards Usable Protection Against Honeypots
Ferreira Torres, Christof UL; Steichen, Mathis UL; State, Radu UL

in IEEE International Conference on Blockchain and Cryptocurrency, Toronto, Canada 3-6 May 2020 (2020)

The Ethereum blockchain enables the execution of so-called smart contracts. These are programs that facilitate the automated transfer of funds according to a given business logic without the participants ... [more ▼]

The Ethereum blockchain enables the execution of so-called smart contracts. These are programs that facilitate the automated transfer of funds according to a given business logic without the participants requiring to trust one another. However, recently attackers started using smart contracts to lure users into traps by deploying contracts that pretend to give away funds but in fact contain hidden traps. This new type of scam is commonly referred to as honeypots. In this paper, we propose a system that aims to protect users from falling into these traps. The system consists of a plugin for MetaMask and a back-end service that continuously scans the Ethereum blockchain for honeypots. Whenever a user is about to perform a transaction through MetaMask, our plugin sends a request to the back-end and warns the user if the target contract is a honeypot. [less ▲]

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See detailProcess mining-based approach for investigating malicious login events
Lagraa, Sofiane UL; State, Radu UL

in IEEE/IFIP Network Operations and Management Symposium, Budapest, Hungary, April 20-24, 2020 (2020)

A large body of research has been accomplished on prevention and detection of malicious events, attacks, threats, or botnets. However, there is a lack of automatic and sophisticated methods for ... [more ▼]

A large body of research has been accomplished on prevention and detection of malicious events, attacks, threats, or botnets. However, there is a lack of automatic and sophisticated methods for investigating malicious events/users, understanding the root cause of attacks, and discovering what is really hap- pening before an attack. In this paper, we propose an attack model discovery approach for investigating and mining malicious authentication events across user accounts. The approach is based on process mining techniques on event logs reaching attacks in order to extract the behavior of malicious users. The evaluation is performed on a publicly large dataset, where we extract models of the behavior of malicious users via authentication events. The results are useful for security experts in order to improve defense tools by making them robust and develop attack simulations. [less ▲]

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See detailIntrusion detection on robot cameras using spatio-temporal autoencoders: A self-driving car application
Amrouche, Faouzi UL; Lagraa, Sofiane UL; Frank, Raphaël UL et al

in 91st IEEE Vehicular Technology Conference, VTC Spring 2020, Antwerp, Belgium, May 25-28, 2020 (2020)

Robot Operating System (ROS) is becoming more and more important and is used widely by developers and researchers in various domains. One of the most important fields where it is being used is the self ... [more ▼]

Robot Operating System (ROS) is becoming more and more important and is used widely by developers and researchers in various domains. One of the most important fields where it is being used is the self-driving cars industry. However, this framework is far from being totally secure, and the existing security breaches do not have robust solutions. In this paper we focus on the camera vulnerabilities, as it is often the most important source for the environment discovery and the decision-making process. We propose an unsupervised anomaly detection tool for detecting suspicious frames incoming from camera flows. Our solution is based on spatio-temporal autoencoders used to truthfully reconstruct the camera frames and detect abnormal ones by measuring the difference with the input. We test our approach on a real-word dataset, i.e. flows coming from embedded cameras of self-driving cars. Our solution outperforms the existing works on different scenarios. [less ▲]

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See detailFeasibility of Stellar as a Blockchain-based Micropayment System
Khan, Nida UL; Ahmad, Tabrez; State, Radu UL

in Springer SmartBlock 2019 - 2nd International Conference on Smart Blockchain (2019, November)

The advent of Bitcoin was heralded as an innovation in the global monetary system, that could bring down transaction fees by circumventing the need for third parties and conduct transactions in real time ... [more ▼]

The advent of Bitcoin was heralded as an innovation in the global monetary system, that could bring down transaction fees by circumventing the need for third parties and conduct transactions in real time. The divisibility of a blockchain cryptocurrency to even fractions of a cent, caused microtransactions to become feasible to formerly non-existent denominations. These microtransactions have spurred the development of novel ways of monetizing online resources and hold the potential to aid in alleviation of poverty. The paper conducts a feasibility study on Stellar as a blockchain-based micropayment system. It highlights the computational and other issues that impedes its progress and utilizes a characterization model for micropayment systems to evaluate the efficacy of the Stellar platform. The paper conducts a comparison with the micropayment solutions from Bitcoin, Ethereum and PayPal. The paper analyzes a subset of transactions from the Stellar blockchain to aid in drawing a conclusion on the undertaken study and elaborates on the mitigation tools to enable fraud prevention in online monetary transactions. [less ▲]

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See detailAuto-encoding Robot State against Sensor Spoofing Attacks
Rivera, Sean UL; Lagraa, Sofiane UL; Iannillo, Antonio Ken UL et al

in International Symposium on Software Reliability Engineering (2019, October)

In robotic systems, the physical world is highly coupled with cyberspace. New threats affect cyber-physical systems as they rely on several sensors to perform critical operations. The most sensitive ... [more ▼]

In robotic systems, the physical world is highly coupled with cyberspace. New threats affect cyber-physical systems as they rely on several sensors to perform critical operations. The most sensitive targets are their location systems, where spoofing attacks can force robots to behave incorrectly. In this paper, we propose a novel anomaly detection approach for sensor spoofing attacks, based on an auto-encoder architecture. After initial training, the detection algorithm works directly on the compressed data by computing the reconstruction errors. We focus on spoofing attacks on Light Detection and Ranging (LiDAR) systems. We tested our anomaly detection approach against several types of spoofing attacks comparing four different compression rates for the auto-encoder. Our approach has a 99% True Positive rate and a 10% False Negative rate for the 83% compression rate. However, a compression rate of 41% could handle almost all of the same attacks while using half the data. [less ▲]

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See detailVisualization of AE's Training on Credit Card Transactions with Persistent Homology
Charlier, Jérémy Henri J. UL; Petit, François UL; Ormazabal, Gaston et al

in Proceedings of the International Workshop on Applications of Topological Data Analysis In conjunction with ECML PKDD 2019 (2019, September)

Auto-encoders are among the most popular neural network architecture for dimension reduction. They are composed of two parts: the encoder which maps the model distribution to a latent manifold and the ... [more ▼]

Auto-encoders are among the most popular neural network architecture for dimension reduction. They are composed of two parts: the encoder which maps the model distribution to a latent manifold and the decoder which maps the latent manifold to a reconstructed distribution. However, auto-encoders are known to provoke chaotically scattered data distribution in the latent manifold resulting in an incomplete reconstructed distribution. Current distance measures fail to detect this problem because they are not able to acknowledge the shape of the data manifolds, i.e. their topological features, and the scale at which the manifolds should be analyzed. We propose Persistent Homology for Wasserstein Auto-Encoders, called PHom-WAE, a new methodology to assess and measure the data distribution of a generative model. PHom-WAE minimizes the Wasserstein distance between the true distribution and the reconstructed distribution and uses persistent homology, the study of the topological features of a space at different spatial resolutions, to compare the nature of the latent manifold and the reconstructed distribution. Our experiments underline the potential of persistent homology for Wasserstein Auto-Encoders in comparison to Variational Auto-Encoders, another type of generative model. The experiments are conducted on a real-world data set particularly challenging for traditional distance measures and auto-encoders. PHom-WAE is the first methodology to propose a topological distance measure, the bottleneck distance, for Wasserstein Auto-Encoders used to compare decoded samples of high quality in the context of credit card transactions. [less ▲]

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See detailMQLV: Optimal Policy of Money Management in Retail Banking with Q-Learning
Charlier, Jérémy Henri J. UL; Ormazabal, Gaston; State, Radu UL et al

in Proceedings of the Fourth Workshop on MIning DAta for financial applicationS (MIDAS 2019) co-located with the 2019 European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML-PKDD 2019) (2019, September)

Reinforcement learning has become one of the best approach to train a computer game emulator capable of human level performance. In a reinforcement learning approach, an optimal value function is learned ... [more ▼]

Reinforcement learning has become one of the best approach to train a computer game emulator capable of human level performance. In a reinforcement learning approach, an optimal value function is learned across a set of actions, or decisions, that leads to a set of states giving different rewards, with the objective to maximize the overall reward. A policy assigns to each state-action pairs an expected return. We call an optimal policy a policy for which the value function is optimal. QLBS, Q-Learner in the Black-Scholes(-Merton) Worlds, applies the reinforcement learning concepts, and noticeably, the popular Q-learning algorithm, to the financial stochastic model of Black, Scholes and Merton. It is, however, specifically optimized for the geometric Brownian motion and the vanilla options. Its range of application is, therefore, limited to vanilla option pricing within the financial markets. We propose MQLV, Modified Q-Learner for the Vasicek model, a new reinforcement learning approach that determines the optimal policy of money management based on the aggregated financial transactions of the clients. It unlocks new frontiers to establish personalized credit card limits or bank loan applications, targeting the retail banking industry. MQLV extends the simulation to mean reverting stochastic diffusion processes and it uses a digital function, a Heaviside step function expressed in its discrete form, to estimate the probability of a future event such as a payment default. In our experiments, we first show the similarities between a set of historical financial transactions and Vasicek generated transactions and, then, we underline the potential of MQLV on generated Monte Carlo simulations. Finally, MQLV is the first Q-learning Vasicek-based methodology addressing transparent decision making processes in retail banking. [less ▲]

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See detailDeep dive into Interledger: Understanding the Interledger ecosystem - Part 3
Trestioreanu, Lucian Andrei UL; Cassagnes, Cyril UL; State, Radu UL

Learning material (2019)

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally ... [more ▼]

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally a protocol for interledger payments. To understand how is it possible to achieve this goal, several aspects of the technology require a deeper analysis. For this reason, in our journey to become knowledgeable and active contributor we decided to create our own test-bed on our premises. By doing so, we noticed that some aspects are well documented but we found that others might need more attention and clarification. Despite a large community effort, the task to keep information on a fast evolving software ecosystem is tedious and not always the priority for such a project. Therefore, the purpose of this document is to guide, through several hands-on activities, community members who want to engage at different levels. The document consolidates all the relevant information from generating a simple payment to ultimately create a test-bed with the Interledger protocol suite between Ripple and other distributed ledger technology. [less ▲]

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See detailDeep dive into Interledger: Understanding the Interledger ecosystem - Part 2
Trestioreanu, Lucian Andrei UL; Cassagnes, Cyril UL; State, Radu UL

Learning material (2019)

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally ... [more ▼]

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally a protocol for interledger payments. To understand how is it possible to achieve this goal, several aspects of the technology require a deeper analysis. For this reason, in our journey to become knowledgeable and active contributor we decided to create our own test-bed on our premises. By doing so, we noticed that some aspects are well documented but we found that others might need more attention and clarification. Despite a large community effort, the task to keep information on a fast evolving software ecosystem is tedious and not always the priority for such a project. Therefore, the purpose of this document is to guide, through several hands-on activities, community members who want to engage at different levels. The document consolidates all the relevant information from generating a simple payment to ultimately create a test-bed with the Interledger protocol suite between Ripple and other distributed ledger technology. [less ▲]

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See detailDeep dive into Interledger: Understanding the Interledger ecosystem - Part 1
Trestioreanu, Lucian Andrei UL; Cassagnes, Cyril UL; State, Radu UL

Learning material (2019)

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally ... [more ▼]

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally a protocol for interledger payments. To understand how is it possible to achieve this goal, several aspects of the technology require a deeper analysis. For this reason, in our journey to become knowledgeable and active contributor we decided to create our own test-bed on our premises. By doing so, we noticed that some aspects are well documented but we found that others might need more attention and clarification. Despite a large community effort, the task to keep information on a fast evolving software ecosystem is tedious and not always the priority for such a project. Therefore, the purpose of this document is to guide, through several hands-on activities, community members who want to engage at different levels. The document consolidates all the relevant information from generating a simple payment to ultimately create a test-bed with the Interledger protocol suite between Ripple and other distributed ledger technology. [less ▲]

Detailed reference viewed: 87 (4 UL)