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CORGI

Christopher Humphries, Nicolas Prigent, Christophe Bidan, Frédéric Majorczyk
2014 Proceedings of the Eleventh Workshop on Visualization for Cyber Security - VizSec '14  
In this article, we present CORGI, a security-oriented log visualization tool that allows security experts to visually explore and link numerous types of log files through relevant representations and global filtering. The analyst can mark values as values of interest and then use these values to pursue the exploration in other log files, allowing him to better understand events and reconstruct attack scenarios. We present the user interface and interactions that ensure these capabilities and
more » ... ovide two use cases based on challenges from VAST and from the Honeynet project.
doi:10.1145/2671491.2671494 dblp:conf/vizsec/HumphriesPBM14 fatcat:b7wx4jfsvje7vaolezjzgtugmq

Challenges in peer-to-peer gaming

Christoph Neumann, Nicolas Prigent, Matteo Varvello, Kyoungwon Suh
2007 Computer communication review  
While multi-player online games are very successful, their fast deployment suffers from their server-based architecture. Indeed, servers both limit the scalability of the games and increase deployment costs. However, they make it easier to control the game (e.g. by preventing cheating and providing support for billing). Peer-to-peer, i.e. transfer of the game functions on each each player's machine, is an attractive communication model for online gaming. We investigate here the challenges of
more » ... r-to-peer gaming, hoping that this discussion will generate a broader interest in the research community.
doi:10.1145/1198255.1198269 fatcat:qofgek66bvbdtd3htcu2fxh7cm

OPTIMAL EMPLOYEE OWNERSHIP CONTRACTS UNDER AMBIGUITY AVERSION

Nicolas Aubert, Hachmi Ben Ameur, Guillaume Garnotel, Jean-Luc Prigent
2017 Economic Inquiry  
The aim of this paper is to compute and describe the conditions of an optimal employee ownership contract between an employer and an ambiguity-averse employee. We then introduce ambiguity aversion in the baseline model of Aubert et al (2014) using the multiple prior preferences of Gilboa and Schmeidler (1989) and its extension proposed by Maccheroni et al (2006) . This model offers solutions that reconcile labor and financial economics and behavioral economics research findings on employee
more » ... ship. The paper focuses on the most common situation where employee ownership has a positive impact on corporate performance, but can also be used as an entrenchment mechanism. We determine the optimal company stock contribution, which corresponds to a perfect subgame Nash equilibrium in the ambiguity framework. Using the framework of Gilboa and Schmeidler's (1989) , we show that the optimal ownership contract is respectively increasing with respect to the lower bound of the return expectation in the case of a high level of effort, and decreasing with respect to the upper bound of the return expectation in the case of a low level of effort. In the framework of Maccheroni et al (2006) , we prove that if aversion to ambiguity is sufficiently high, then we find the same behavior as in the case of no ambiguity. 5 JEL classification: G11, G32, G34, J33.
doi:10.1111/ecin.12478 fatcat:nejlgusonfaehk2zvfot6bq5aa

Homomorphic Cryptography-Based Privacy-Preserving Network Communications [chapter]

Antoine Guellier, Christophe Bidan, Nicolas Prigent
2014 Communications in Computer and Information Science  
The development of worldwide communications, along with the dramatic increase of computational and storage capacities promise numerous benefits for societies in the years to come. For these systems to develop, security and privacy are necessary. This work presents a novel protocol for privacy preserving network communications, using homomorphic cryptography. The malleability properties of homomorphic encryption allows routing without ever disclosing the sender or receiver of a message, while
more » ... isting against basic end-to-end attacks. We first present our protocol in an abstract network model, and instantiate it for ad-hoc networks as a use-case example. Destination/message unlinkability (DMU) Given a message m and a node D, it is impossible to distinguish whether D is the destination of m or not; Source/destination unlinkability (SDU) Given two nodes, it is impossible to distinguish whether they communicated or not; Message/message unlinkability (MMU) Given two messages, it is impossible to distinguish whether they belong to the same source-destination pair communication or not; Adversary Model. We consider two adversary models: a passive, non-collusive adversary internal to the network (also called honest-but-curious) (AdvI), and a global eavesdropper (AdvII). The first type of adversary participates in the network and is compliant with the protocol, but tries to get as much knowledge as possible on the network and other nodes. The second is still passive but more powerful, although it does not participate in the network. We do not give the adversary the ability to tamper with the network by dropping, replaying, or performing DoS or Sybil attacks for instance. Note that when considering information theoretic adversaries, notably against cryptographic primitives, we use the probabilistic polynomial-time (PPT) model. In any case, the goal of the adversary is to break the properties stated above.
doi:10.1007/978-3-662-45670-5_15 fatcat:nymfbxyq6nbi3jkg3ew2sd5fre

Improving Secure Device Insertion in Home Ad Hoc Networks [chapter]

Olivier Heen, Jean-Pierre Andreaux, Nicolas Prigent
2004 Security and Protection in Information Processing Systems  
Acknowledgments The authors would like to thank Nicolas Prigent and Alain Durand for valuable remarks and support.  ...  Prigent and C. Bidan. Other solutions already exists within standards such as UPnP [6] , Bluetooth [2] , 802.11 with activated security features [5] or Zigbee [7] .  ... 
doi:10.1007/1-4020-8143-x_25 dblp:conf/sec/HeenAP04 fatcat:n3ppyziwnzd5rhh5j5cnfh7boa

PET/CT variants and pitfalls in malignant melanoma

Nicolas Aide, Amir Iravani, Kevin Prigent, Diane Kottler, Ramin Alipour, Rodney J. Hicks
2022 Cancer Imaging  
Abstract18F-FDG PET/CT plays an increasingly pivotal role in the staging and post-treatment monitoring of high-risk melanoma patients, augmented by the introduction of therapies, including tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors (ICIs), that have novel modes of action that challenge conventional response assessment. Simultaneously, technological advances have been regularly released, including advanced reconstruction algorithms, digital PET and motion correction, which
more » ... have allowed the PET community to detect ever-smaller cancer lesions, improving diagnostic performance in the context of indications previously viewed as limitations, such as detection of in-transit disease and confirmation of the nature of small pulmonary metastases apparent on CT.This review will provide advice regarding melanoma-related PET protocols and will focus on variants encountered during the imaging of melanoma patients. Emphasis will be made on pitfalls related to non-malignant diseases and treatment-related findings that may confound accurate interpretation unless recognized. The latter include signs of immune activation and immune-related adverse events (irAEs). Technology-related pitfalls are also discussed, since while new PET technologies improve detection of small lesions, these may also induce false-positive cases and require a learning curve to be observed. In these times of the COVID 19 pandemic, cases illustrating lessons learned from COVID 19 or vaccination-related pitfalls will also be described.
doi:10.1186/s40644-021-00440-4 pmid:34983677 pmcid:PMC8724662 fatcat:7ugewntmb5e2joysucyprcuzra

Swallowing dysfunction in patients hospitalised due to a COPD exacerbation: correspondence

Nicolas Terzi, Hélène Prigent, Frédéric Lofaso
2021 ERJ Open Research  
Footnotes Nicolas Terzi has received personal fees from Pfizer outside this work Frédéric Lofaso and Hélène Prigent have nothing to disclose  ... 
doi:10.1183/23120541.00490-2021 pmid:34708117 pmcid:PMC8542965 fatcat:seylzexyjbbzdjgzj6ut3uexrq

VEGAS: Visualizing, exploring and grouping alerts

Damien Cremilleux, Christophe Bidan, Frederic Majorczyk, Nicolas Prigent
2016 NOMS 2016 - 2016 IEEE/IFIP Network Operations and Management Symposium  
doi:10.1109/noms.2016.7502968 dblp:conf/noms/CremilleuxBMP16 fatcat:renri3dwq5gu5diqoko475exnu

Diaphragm Ultrasound in Cardiac Surgery: State of the Art

Abdallah Fayssoil, Nicolas Mansencal, Lee S. Nguyen, David Orlikowski, Hélène Prigent, Jean Bergounioux, Djillali Annane, Frédéric Lofaso
2022 Medicines  
In cardiac surgery, patients are at risk of phrenic nerve injury, which leads to diaphragm dysfunction and acute respiratory failure. Diaphragm dysfunction (DD) is relatively frequent in cardiac surgery and particularly affects patients after coronary artery bypass graft. The onset of DD affects patients' prognosis in term of weaning from mechanical ventilation and hospital length of stay. The authors present a narrative review about diaphragm physiology, techniques used to assess diaphragm
more » ... tion, and the clinical application of diaphragm ultrasound in patients undergoing cardiac surgery.
doi:10.3390/medicines9010005 pmid:35049938 pmcid:PMC8779362 fatcat:cmmozzdlrzdpdptg7jcw6mqziq

STARLORD: Linked security data exploration in a 3D graph

Laetitia Leichtnam, Eric Totel, Nicolas Prigent, Ludovic Me
2017 2017 IEEE Symposium on Visualization for Cyber Security (VizSec)  
In this paper, we present a novel modelization and visualization approach for heterogeneous sources of data. We represent our data by using a model inspired by STIX. Then, we use clustering algorithms to select interesting information to explore in a visualization panel. The visualization is based on a 3D graph representation that highlights the link between malicious event and allows to focus on relevant security artifacts. We illustrate our approach with two case studies using datasets containing network capture of the wannacry attack.
doi:10.1109/vizsec.2017.8062203 dblp:conf/vizsec/LeichtnamTPM17 fatcat:nvd44zohsjge7lftap5yi3365e

Impact of tracheostomy on swallowing performance in Duchenne muscular dystrophy

Nicolas Terzi, Hélène Prigent, Michèle Lejaille, Line Falaize, Djillali Annane, David Orlikowski, Frédéric Lofaso
2010 Neuromuscular Disorders  
Mechanical ventilation has improved survival in patients with Duchenne muscular dystrophy (DMD). Over time, these patients experience upper airway dysfunction, swallowing impairments, and dependency on the ventilator that may require invasive mechanical ventilation via a tracheostomy. Tracheostomy is traditionally believed to further impair swallowing. To evaluate the effect of tracheostomy on swallowing we assessed swallowing performance and breathing-swallowing interactions before and after
more » ... acheostomy in 7 consecutive wheelchair-bound DMD patients, aged 25±4 years; over a 4-year period. Chin electromyography, laryngeal motion, and inductive respiratory plethysmography recordings were obtained during swallowing of three water-bolus sizes in random order. The evaluations were done before and after tracheostomy. Piecemeal deglutition occurred in all patients over several breathing cycles. Half the swallows were followed by inspiration before tracheostomy. Total bolus swallowing time was significantly shorter (P=0.009) and the number of swallows per bolus significantly smaller (P=0.01) after than before tracheostomy. Invasive ventilation via a tracheostomy may improve swallowing. Abstract word count: 153 pour un maximum de 150
doi:10.1016/j.nmd.2010.05.009 pmid:20558065 fatcat:2iiypnsglvecxbwgynug5lsjlm

From Donor to Recipient: Current Questions Relating to Humoral Alloimmunization

Antoine Prigent, Nicolas Maillard, Léna Absi, Chaker Aloui, Fabrice Cognasse, Sandrine Laradi, Christophe Mariat, Olivier Garraud
2014 Antibodies  
Alloimmunization is an undesirable iatrogenic effect of transfusion and transplantation. In fact, recipients can be considered as responders or not responders, in a continuum from tolerance, including organ transplantation and transfusion, to polyimmunized and refractory patients. New models and large studies have enabled a better understanding of the mechanisms that induce specific alloantibody (alloAb) generation. Here, we focus on risk factors of alloimmunization. We review the alloantibody
more » ... haracteristics, summarize the different leukocytes involved in their induction, and suggest some hypotheses.
doi:10.3390/antib3010130 fatcat:xs2u3ivfonakbkljizuij3qhtm

Sec2graph: Network Attack Detection Based on Novelty Detection on Graph Structured Data [chapter]

Laetitia Leichtnam, Eric Totel, Nicolas Prigent, Ludovic Mé
2020 Lecture Notes in Computer Science  
Being able to timely detect new kinds of attacks in highly distributed, heterogeneous and evolving networks without generating too many false alarms is especially challenging. Many researchers proposed various anomaly detection techniques to identify events that are inconsistent with past observations. While supervised learning is often used to that end, security experts generally do not have labeled datasets and labeling their data would be excessively expensive. Unsupervised learning, that
more » ... s not require labeled data should then be used preferably, even if these approaches have led to less relevant results. We introduce in this paper a unified and unique graph representation called security objects' graphs. This representation mixes and links events of different kinds and allows a rich description of the activities to be analyzed. To detect anomalies in these graphs, we propose an unsupervised learning approach based on auto-encoder. Our hypothesis is that as security objects' graphs bring a rich vision of the normal situation, an autoencoder is able to build a relevant model of this situation. To validate this hypothesis, we apply our approach to the CICIDS2017 dataset and show that although our approach is unsupervised, its detection results are as good, and even better than those obtained by many supervised approaches.
doi:10.1007/978-3-030-52683-2_12 fatcat:qn52lph33jez5j6uneiztzibnm

AN INDUSTRIAL AND ACADEMIC JOINT EXPERIMENT ON AUTOMATED VERIFICATION OF A SECURITY PROTOCOL

OLIVIER HEEN, THOMAS GENET, STEPHANE GELLER, NICOLAS PRIGENT
2008 Mobile and Wireless Networks Security  
This paper relates the collaboration between industrial and academic teams for the design and the verification of a security protocol. The protocol is about trust establishment in large communities of devices where infrastructure components are not always reachable. The collaboration covers the writing of formal specifications up to their verification, using both manual and automated verification methods embedded in the AVISPA [1] and SPAN [7] tools. At each stage, the use of the visualization
more » ... nd protocol animation facilities of SPAN is key to the mutual understanding of working teams. As a result, we obtain much more confidence in the security of the final protocol. We also demonstrate the usefulness of some embedded countermeasures.
doi:10.1142/9789812833266_0004 fatcat:qowi6ap2xbf27j6ca727ma4jp4

Compressed video stream watermarking for peer-to-peer based content distribution network

Dekun Zou, Nicolas Prigent, Jeffrey Bloom
2009 2009 IEEE International Conference on Multimedia and Expo  
Peer-to-peer content distribution provides high network throughput with relatively low server cost and scales better than traditional content distribution networks with respect to the number of clients. It is ideal for applications requiring large data transfer such as Video-on-Demand or live video streaming. Traditional forensic watermarking systems are based on the assumption that each user receives a unique copy of video content to allow for tracking of pirated content back to the original
more » ... cipient. However, P2P-based distribution systems are typically designed to supply identical copies to each user. This paper proposes a new watermarking framework that is suitable for P2P-based content delivery systems. Watermarking algorithms that are appropriate for this system are also discussed.
doi:10.1109/icme.2009.5202763 dblp:conf/icmcs/ZouPB09 fatcat:aldjont5jvfenicubnp7escqdy
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