29 research outputs found
D3S: A Framework for Enabling Unmanned Aerial Vehicles as a Service
In this paper, we consider the use of UAVs to provide wireless connectivity
services, for example after failures of wireless network components or to
simply provide additional bandwidth on demand, and introduce the concept of
UAVs as a service (UaaS). To facilitate UaaS, we introduce a novel framework,
dubbed D3S, which consists of four phases: demand, decision, deployment, and
service. The main objective of this framework is to develop efficient and
realistic solutions to implement these four phases. The technical problems
include determining the type and number of UAVs to be deployed, and also their
final locations (e.g., hovering or on-ground), which is important for serving
certain applications. These questions will be part of the decision phase. They
also include trajectory planning of UAVs when they have to travel between
charging stations and deployment locations and may have to do this several
times. These questions will be part of the deployment phase. The service phase
includes the implementation of the backbone communication and data routing
between UAVs and between UAVs and ground control stations
Early detection of Myocardial Infarction using WBAN
International audienceCardiovascular diseases are the leading cause of death in the world, and Myocardial Infarction (MI) is the most serious one among those diseases. Patient monitoring for an early detection of MI is important to alert medical assistance and increase the vital prognostic of patients. With the development of wearable sensor devices having wireless transmission capabilities, there is a need to develop real-time applications that are able to accurately detect MI non-invasively. In this paper, we propose a new approach for early detection of MI using wireless body area networks. The proposed approach analyzes the patient electrocardiogram (ECG) in real time and extracts from each ECG cycle the ST elevation which is a significant indicator of an upcoming MI. We use the sequential change point detection algorithm CUmulative SUM (CUSUM) to early detect any deviation in ST elevation time series, and to raise an alarm for healthcare professionals. The experimental results on the ECG of real patients show that our proposed approach can detect MI with low delay and high accuracy
Pas de titre en français
Pas de résumé en françaisSession Initiation Protocol (SIP) is the widely used signaling protocol for voiceand video communication as well as other multimedia applications. Despiteof its flexibility and a common standard that can be leveraged to efficientlycombine a wide array of communication systems and technologies, it is exposedto a number of problems, including the vulnerability to several types of attacksdue to its open nature, in particular, and lack of a clear defense line. Likewise,flooding attack is one of the most destructive attacks targeting both User AgentServer (UAS) and User Agent Client (UAC), leading to a Denial of Service (DoS)in VoIP applications. In particular, INVITE message is considered as one of themajor root causes of flooding attacks in SIP. This is due to the fact that an attackermay send numerous INVITE requests without waiting for responses from theUAS or proxy in order to exhaust their resources. Moreover, SPIT problem inSIP is also a challenging issue which needs proper attention and appropriatesolutions.Most of the solutions proposed to overcome the flooding attacks are eitherdifficult to deploy in practice or require significant changes in the SIP servers.Additionally, the diverse nature of flooding attacks offers a huge challenge toenvisage appropriate prevention mechanisms. In this survey, we present acomprehensive study on flooding attacks against SIP by addressing its differentvariants and analyzing its consequences. We also classify the existing solutionscorresponding to different flooding behaviors, types and targets, and then weperform an extensive investigation of their main weaknesses and strengths.Additionally, we also take into account the underlying assumptions of eachsolution for a better understanding of its limitations. Specifically, we havethoroughly analyzed SPIT problems and few of the existing solutions proposedfor their prevention.The theoretical framework derived from our extensive literature survey led us topropose a solution for handling specific number of SIP requests in a particulartime window. Our proposed "Light Weight Scheme" is implemented in a SERSIP server. The evaluation results presented in this thesis depict the satisfactoryperformance of this approach. In order to cope with SIP flooding attacks, wepropose another solution based on "Strategy Based Proxy". This solution isdesigned for a SIP proxy that calculates the probability of a call being maliciouson the basis of its current experience. The obtained experience is also utilized tocalculate the probabilities of a successful call setup. This approach is useful forboth state-ful and state-less proxy servers.For dealing with SPIT, we have designed a 2-step solution. In first step, weextract the useful information from the VoIP traffic. In second step, we apply aNaive Bayes classifier on the date extracted from first step to determine whetherthe nature of an incoming SIP call is malicious or it is a harmless routine call.With this mechanism, we can detect the SPIT calls from a group of incomingSIP calls. Finally, we presents a detailed discussion and conclusions derivedfrom our case study carried out in this thesis along with future directions andpotential research areas related to VoIP security threats.PARIS5-Bibliotheque electronique (751069902) / SudocSudocFranceF
Sécurité des protocoles de routage et d accès au médium dans les réseaux sans fil multi-sauts
Récemment, les comportements malveillants dans les réseaux sans fil multi-sauts ont attiré l attention de la communauté scientifique. La prolifération rapide du nombre de dispositifs sans fil ainsi que la diversification des applications basées sur ces réseaux ont grandement contribué à l amélioration de la qualité de vie ainsi que la modernisation de la société. Cependant, la nécessité de sécuri ser ces réseaux et de garantir la robustesse de leurs services est devenue une préoccupation majeure. En effet, les caractéristiques spécifiques de ces réseaux, telles que l absence d infrastructure et l absence d une entité centrale de confiance, font que les réponses à leurs problèmes de sécurité sont tout à fait différentes de celles des réseaux filaires. De plus, le manque de confiance entre les nœuds rend ces problèmes encore plus critiques. L objectif de cette thèse vise à contribuer au renforcement de la sécurité dans les réseaux sans fil multi-sauts. Elle se focalise sur l étude des comportements malveillants au niveau des couches MAC et réseau. Nous nous intéressons au développement de nouvelles solutions pour faire face à l attaque du trou noir Black hole dans le contexte du protocole OLSR, ainsi qu analyser le comportement des nœuds cupides Greedy au niveau de la couche MAC, dans toutes ses versions.Une attaque de trou noir peut être menée suivant deux scénarios. Le premier scénario consiste à lancer l attaque, exclusivement, au niveau de la couche réseau. Le second scénario consiste en une attaque multi-couches. Dans le cadre de cette thèse, nous analysons l impact de ces deux types d attaques et proposons des contre-mesures appropriées. Au niveau de la couche MAC, nous étudions particulièrement le comportement cupide adaptatif dans le cadre des réseaux sans fil maillés et nous proposons une solution originale baptisée, FLSAC, afin de prévenir ce type de menace. Dans le cadre des réseaux mobiles ad hoc (MANETs), nous définissons un nouveau modèle de comportement des nœuds cupides. Nous développons aussi un nouvel algorithme de backoff, dont l avantage principal est d assurer une détection rapide des nœuds cupides non conformes aux spécifications du protocole IEEE802.11. Cet algorithme offre un mécanisme de réaction qui incite un nœud cupide à se comporter correctement en lui donnant la chance de se repentir après détection.While the rapid proliferation of mobile devices along with the tremendous growth of various applications using wireless multi-hop networks have significantly facilitate our human life, securing and ensuring high quality services of these networks are still a primary concern. In particular, anomalous protocol operation in wireless multi-hop networks has recently received considerable attention in the research community. These relevant security issues are fundamentally different from those of wireline networks due to the special characteristics of wireless multi-hop networks, such as the limited energy resources and the lack of centralized control. These issues are extremely hard to cope with due to the absence of trust relationships between the nodes.To enhance security in wireless multi-hop networks, this dissertation addresses both MAC and routing layers misbehaviors issues, with main focuses on thwarting black hole attack in proactive routing protocols like OLSR, and greedy behavior in IEEE 802.11 MAC protocol. Our contributions are briefly summarized as follows. As for black hole attack, we analyze two types of attack scenarios: one is launched at routing layer, and the other is cross layer. We then provide comprehensive analysis on the consequences of this attack and propose effective countermeasures. As for MAC layer misbehavior, we particularly study the adaptive greedy behavior in the context of Wireless Mesh Networks (WMNs) and propose FLSAC (Fuzzy Logic based scheme to Struggle against Adaptive Cheaters) to cope with it. A new characterization of the greedy behavior in Mobile Ad Hoc Networks (MANETs) is also introduced. Finally, we design a new backoff scheme to quickly detect the greedy nodes that do not comply with IEEE 802.11 MAC protocol, together with a reaction scheme that encourages the greedy nodes to become honest rather than punishing them.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF
QoS Control and Adaptation in Distributed Multimedia Systems
Abstract. Presently, many distributed multimedia systems adapt to their changing environments and Quality of Service (QoS) requirements by exchanging control and feedback data between servers and clients. In order to realize a more flexible adaptation to QoS in distributed multimedia systems, this paper seeks to present a new approach, based on distributed software agents located in both network nodes and end-systems. By having a good knowledge of local resources at each component, and with their capabilities to communicate in order to share their knowledge, the distributed software agents can alleviate the major fluctuations in QoS, by providing load balancing and resource sharing between the competing connections. In order to show the feasibility of our active adaptation approach, simulations have been conducted to adapt a delay sensitive flow such as distributed interactive virtual environment. We have performed our evaluations for short and long range (i.e. self-similar) traffic patterns. Preliminary results show a viable system, which exhibits a smooth and noticeable improvement in perceptual QoS during a heavy loaded network. In addition, our results indicate that the network and the application have more to benefit from the algorithm, when the traffic exhibits long range dependence behavior.
Performance modelling of the O-MAC protocol
In this paper we derive a qualitative model for O-MAC, an energy efficient MAC protocol designed for sensor networks. Through this model we study how each parameter, such as packet sending rate, node density and end-to-end hop lengths, affects the performance of O-MAC and the limitation of current O-MAC protocol. More-over, the model gives us the direction of with which to modify the current O-MAC protocol to improve its performance. Copyright 2007 ACM
An ECG Monitoring System For Prediction Of Cardiac Anomalies Using WBAN
International audienceCardiovascular diseases (CVD) are known to be the most widespread causes to death. Therefore, detecting earlier signs of cardiac anomalies is of prominent importance to ease the treatment of any cardiac complication or take appropriate actions. Electrocardiogram (ECG) is used by doctors as an important diagnosis tool and in most cases, it's recorded and analyzed at hospital after the appearance of first symptoms or recorded by patients using a device named holter ECG and analyzed afterward by doctors. In fact, there is a lack of systems able to capture ECG and analyze it remotely before the onset of severe symptoms. With the development of wearable sensor devices having wireless trans-mission capabilities, there is a need to develop real time systems able to accurately analyze ECG and detect cardiac abnormalities. In this paper, we propose a new CVD detection system using Wireless Body Area Networks (WBAN) technology. This system processes the captured ECG using filtering and Undecimated Wavelet Transform (UWT) techniques to remove noises and extract nine main ECG diagnosis parameters, then the system uses a Bayesian Network Classifier model to classify ECG based on its parameters into four different classes: Normal, Premature Atrial Contraction (PAC), Premature Ventricular Contraction (PVC) and Myocardial Infarction (MI). The experimental results on ECGs from real patients databases show that the average detection rate (TPR) is 96.1% for an average false alarm rate (FPR) of 1.3%
Performance analysis of an energy efficient MAC protocol for sensor networks
In this paper we derive a qualitative model for O-MAC, an energy efficient MAC protocol designed for sensor networks. Through this model we study how each parameter, such as packet sending rate, node density and end-to-end hop lengths, affects the performance of O-MAC and the limitation of current O-MAC protocol. Moreover, the model gives us the direction of with which to modify the current O-MAC protocol to improve its performance. © 2008 IEEE