The thesis describes development and optimization process of an inductively coupled coil corrosion potential sensor for long-term civil structure health monitoring remotely. This is of growing interest for decreasing the maintenance cost, reducing the deterioration significantly and increasing the safety. The thesis is organized accordingly introduction, circuit modeling of the sensor, optimization and fabrication of the sensors and the simulated and experimental results from new and existing civil structure. The two geometrical design, cylindrical shape and Printed Circuit Board (PCB) based sensor parts of this research and their encapsulation technique for long-term enduring in harsh and corrosive environment of the civil infrastructure is described in the thesis. Results of an accelerated corrosion test on an embedded cylindrical shaped sensor indicates that the corrosion potential can be monitored with less than 10 mV resolution with a sensor sensitivity of ~0.73 kHz/mV. The last part describes a novel technique for a PCB sensor to simulate the existing structure already contaminated with corrosive substances such as chlorides. Two encapsulation techniques, non-conductive epoxy sealed and PLEXIGLAS with air gap sealed embedded PCB sensors response are compared from the accelerated corrosion test on new and built-in civil structure. Finally, results from the accelerated corrosion tests using the two encapsulation techniques mentioned above demonstrate that the embedded sensor in an existing structure may take up to 60 days to see the significant corrosion with a sensor sensitivity of ~ 1.53 kHz/mV or ~ 1.63 kHz/mV respectively. Since chlorides take many years to diffuse into concrete used for civil structures these sensors will respond fast enough to be used in existing structures as well as in new structures.

The Internet plays an important role in modern society, and its network performance impacts billions of users every day. For many network applications, network latency has a large impact on the quality of experience for the end user. Due to a lack of extensive network latency monitoring, the observability of network latency in real networks is often limited. This poses a problem for understanding network latency on the Internet today, and for assessing the impact various solutions that aim to reduce network latency have once they are deployed in the wild. This thesis addresses shortcomings with current solutions for monitoring network latency, in particular the performance of passive monitoring solutions on general-purpose commodity hardware, aiming to enable more ubiquitous latency monitoring and ultimately provide a comprehensive view of real-world network latency. We utilize the recently emerging eBPF technology to implement passive network latency monitoring inside the Linux kernel. Through experiments on a testbed, we show that our solution can monitor packets at over an order of magnitude higher rates than comparable previous solutions, allowing it to successfully monitor the latency for multi-gigabit traffic on general-purpose commodity hardware. Additionally, we demonstrate the feasibility of continuously monitoring network latency by deploying our solution inside an Internet Service Provider and monitoring the network latency for all customer traffic. Through an extensive analysis of the collected latency data, we show large differences in how network latency is distributed across different parts of the network. / The Internet plays a vital role in modern society, and its performance affects billions of users daily. Network latency often has a significant impact on the end users' experience. However, due to limited monitoring of network latency, the observability of latency in real networks is often poor. This hinders our understanding of latency on the Internet today and makes it challenging to assess how the deployment of new networking technologies impacts latency. This thesis uses the emerging eBPF technology to improve the performance of passive network latency monitoring, aiming to enable latency monitoring on more network devices to create a more comprehensive view of latency on the Internet. By conducting controlled experiments on a testbed, we find that our solution is over an order of magnitude faster than previous solutions, making it possible to monitor multi-gigabit traffic on general-purpose commodity hardware. Furthermore, we demonstrate the feasibility of continuously monitoring latency by deploying our solution inside the network of an Internet Service Provider to monitor all their traffic. Our analysis of the latency data reveals large differences in how latency is distributed across different parts of the network.

GARCIA, Fernando Parente. EPMOSt: um sistema de monitoramento passivo energeticamente eficiente para redes de sensores sem fio. 2014. 115 f. Tese (Doutorado em ciência da computação)- Universidade Federal do Ceará, Fortaleza-CE, 2014. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-19T19:35:08Z No. of bitstreams: 1 2014_tese_fpgarcia.pdf: 3632932 bytes, checksum: c2ab75ac7a41921760c110a2d98e4c5b (MD5) / Approved for entry into archive by Rocilda Sales (rocilda@ufc.br) on 2016-07-25T11:41:57Z (GMT) No. of bitstreams: 1 2014_tese_fpgarcia.pdf: 3632932 bytes, checksum: c2ab75ac7a41921760c110a2d98e4c5b (MD5) / Made available in DSpace on 2016-07-25T11:41:57Z (GMT). No. of bitstreams: 1 2014_tese_fpgarcia.pdf: 3632932 bytes, checksum: c2ab75ac7a41921760c110a2d98e4c5b (MD5) Previous issue date: 2014 / Monitoring systems are important for debugging and analyzing Wireless Sensor Networks (WSN). In passive monitoring, a monitoring network needs to be deployed in addition to the network to be monitored, called target network. The monitoring network captures and analyzes packets sent by the target network. An energy-efficient passive monitoring system is necessary when there is a need to monitor a WSN in a real scenario because the lifetime of the monitoring network is extended and, consequently, the target network benefits from the monitoring for a longer time. In this thesis, initially, the main passive monitoring systems proposed for WSN have been identified, analyzed and compared. During the literature review, no passive monitoring system for WSN that aims to reduce the energy consumption of the monitoring network has been identified. Therefore, this thesis proposes an Energy-efficient Passive MOnitoring System for WSN (EPMOSt) that extends the lifetime of the monitoring network. EPMOSt uses two mechanisms to reduce the energy consumption of the monitoring network: sniffer election and aggregation of headers. By using the sniffer election, in general only one sniffer (a node of the monitoring network) captures packets sent by a given node of the target network, thereby reducing the transmission of packets captured by the monitoring network and, thus, considerably reducing the energy consumption of this network. By using aggregation of headers, only the information present in the headers of captured packets is sent through the monitoring network. Thus, the headers of several packets may be sent in the same monitoring message, hence reducing the overhead of transmission and consequently reducing the energy consumption of the monitoring network. Experiments performed with real sensors and with a WSN simulator in various scenarios are conducted to evaluate the proposed monitoring system. The obtained results show the energy efficiency of the EPMOSt and the viability of using it to monitor WSN in real scenarios. / Sistemas de monitoramento permitem depurar e analisar o funcionamento de uma Rede de Sensores Sem Fio (RSSF). No monitoramento passivo, uma rede de monitoramento adicional é implantada com o intuito de capturar e analisar os pacotes transmitidos pela rede a ser monitorada, denominada rede alvo. Quando se deseja monitorar uma RSSF em um ambiente real, um sistema de monitoramento passivo energeticamente eficiente é necessário, pois, caso contrário, a rede de monitoramento pode ter um tempo de vida bem menor do que a rede alvo. Nesta tese, inicialmente, os principais sistemas de monitoramento passivo propostos para RSSF foram identificados, analisados e comparados. Durante as pesquisas realizadas na literatura, não foi identificado nenhum sistema de monitoramento passivo que se preocupasse em reduzir o consumo de energia da rede de monitoramento. Sendo assim, esta tese propõe um sistema de monitoramento passivo energeticamente eficiente para RSSF, denominado EPMOSt (Energy-efficient Passive MOnitoring System), que prolonga o tempo de vida da rede de monitoramento. O EPMOSt utiliza dois mecanismos para reduzir o consumo de energia da rede de monitoramento: eleição de sniffers (nós da rede de monitoramento) e agregação de cabeçalhos. A eleição de sniffers garante que durante a maior parte do tempo apenas um sniffer captura os pacotes transmitidos por um determinado nó da rede alvo, reduzindo assim a transmissão de pacotes capturados redundantes através da rede de monitoramento e, consequentemente, reduzindo consideravelmente o consumo de energia desta rede. Com a agregação de cabeçalhos, apenas as informações presentes nos cabeçalhos dos pacotes capturados são enviadas através da rede de monitoramento. Assim, os cabeçalhos de vários pacotes podem ser enviados na mesma mensagem de monitoramento, reduzindo assim o overhead de transmissão e, consequentemente, reduzindo também o consumo de energia da rede de monitoramento. Experimentos com sensores reais e com um simulador de RSSF são realizados em vários cenários para avaliar o sistema de monitoramento proposto. Os resultados obtidos mostram a eficiência energética do EPMOSt e a viabilidade de utilizá-lo para monitorar RSSF em ambientes reais.

Many network operators need to be able to ensure that customers get the level of service they pay for. To avoid bandwidth and server performance bottlenecks, and easily troubleshoot network problems, the network providers need to be able to see what payload data is sent. Modern networks encrypt data when sending it between nodes that makes passive monitoring more complex. A prevalent encryption mechanism on an IP-based network is TLS that needs to be decrypted.                This article’s purpose is to check if it is possible to decrypt TLS traffic in a passive monitoring system with the server’s private key. This is done by implementing a decryptor in a passive monitoring system in the programming language Java. The implemented solution intercepts the traffic, takes out relevant data from the traffic, and derives the session key from that data. How this is done is dependent on what cipher suite is used for the session. Because of delimitations and lack of time the solution is only able to decrypt the cipher suite TLS_RSA_WITH_AES_128_CBC_SHA256. The result showed that it is possible to decrypt TLS traffic and should be possible for more than the specified cipher suite. But there exists a major problem that's called forward secrecy. This is used in the key exchange algorithm called Diffie–Hellman and makes it impossible to decrypt with only server private key. The conclusion is that it is possible but because of forward secrecy, it is not recommended. TLS 1.3 only uses cipher suites with the key exchange algorithm Diffie–Hellman and the forward secrecy functionality is important for security.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2014-09-30T11:49:04Z No. of bitstreams: 2 Muro Júnior, Aldo-2013-tese.pdf: 3200192 bytes, checksum: 7297291a69938b3b69e4669ecb2b5490 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-09-30T15:31:14Z (GMT) No. of bitstreams: 2 Muro Júnior, Aldo-2013-tese.pdf: 3200192 bytes, checksum: 7297291a69938b3b69e4669ecb2b5490 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-09-30T15:31:14Z (GMT). No. of bitstreams: 2 Muro Júnior, Aldo-2013-tese.pdf: 3200192 bytes, checksum: 7297291a69938b3b69e4669ecb2b5490 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-06-28 / The aim... / O objetivo...

nÃo hà / Monitoring systems are important for debugging and analyzing Wireless Sensor Networks (WSN). In passive monitoring, a monitoring network needs to be deployed in addition to the network to be monitored, called target network. The monitoring network captures and analyzes packets sent by the target network. An energy-efficient passive monitoring system is necessary when there is a need to monitor a WSN in a real scenario because the lifetime of the monitoring network is extended and, consequently, the target network benefits from the monitoring for a longer time. In this thesis, initially, the main passive monitoring systems proposed for WSN have been identified, analyzed and compared. During the literature review, no passive monitoring system for WSN that aims to reduce the energy consumption of the monitoring network has been identified. Therefore, this thesis proposes an Energy-efficient Passive MOnitoring System for WSN (EPMOSt) that extends the lifetime of the monitoring network. EPMOSt uses two mechanisms to reduce the energy consumption of the monitoring network: sniffer election and aggregation of headers. By using the sniffer election, in general only one sniffer (a node of the monitoring network) captures packets sent by a given node of the target network, thereby reducing the transmission of packets captured by the monitoring network and, thus, considerably reducing the energy consumption of this network. By using aggregation of headers, only the information present in the headers of captured packets is sent through the monitoring network. Thus, the headers of several packets may be sent in the same monitoring message, hence reducing the overhead of transmission and consequently reducing the energy consumption of the monitoring network. Experiments performed with real sensors and with a WSN simulator in various scenarios are conducted to evaluate the proposed monitoring system. The obtained results show the energy efficiency of the EPMOSt and the viability of using it to monitor WSN in real scenarios. / Sistemas de monitoramento permitem depurar e analisar o funcionamento de uma Rede de Sensores Sem Fio (RSSF). No monitoramento passivo, uma rede de monitoramento adicional à implantada com o intuito de capturar e analisar os pacotes transmitidos pela rede a ser monitorada, denominada rede alvo. Quando se deseja monitorar uma RSSF em um ambiente real, um sistema de monitoramento passivo energeticamente eficiente à necessÃrio, pois, caso contrÃrio, a rede de monitoramento pode ter um tempo de vida bem menor do que a rede alvo. Nesta tese, inicialmente, os principais sistemas de monitoramento passivo propostos para RSSF foram identificados, analisados e comparados. Durante as pesquisas realizadas na literatura, nÃo foi identificado nenhum sistema de monitoramento passivo que se preocupasse em reduzir o consumo de energia da rede de monitoramento. Sendo assim, esta tese propÃe um sistema de monitoramento passivo energeticamente eficiente para RSSF, denominado EPMOSt (Energy-efficient Passive MOnitoring System), que prolonga o tempo de vida da rede de monitoramento. O EPMOSt utiliza dois mecanismos para reduzir o consumo de energia da rede de monitoramento: eleiÃÃo de sniffers (nÃs da rede de monitoramento) e agregaÃÃo de cabeÃalhos. A eleiÃÃo de sniffers garante que durante a maior parte do tempo apenas um sniffer captura os pacotes transmitidos por um determinado nà da rede alvo, reduzindo assim a transmissÃo de pacotes capturados redundantes atravÃs da rede de monitoramento e, consequentemente, reduzindo consideravelmente o consumo de energia desta rede. Com a agregaÃÃo de cabeÃalhos, apenas as informaÃÃes presentes nos cabeÃalhos dos pacotes capturados sÃo enviadas atravÃs da rede de monitoramento. Assim, os cabeÃalhos de vÃrios pacotes podem ser enviados na mesma mensagem de monitoramento, reduzindo assim o overhead de transmissÃo e, consequentemente, reduzindo tambÃm o consumo de energia da rede de monitoramento. Experimentos com sensores reais e com um simulador de RSSF sÃo realizados em vÃrios cenÃrios para avaliar o sistema de monitoramento proposto. Os resultados obtidos mostram a eficiÃncia energÃtica do EPMOSt e a viabilidade de utilizÃ-lo para monitorar RSSF em ambientes reais.

Aujourd’hui, les appareils mobiles sont présents dans le monde entier. Ces appareils permettent aux utilisateurs d'accéder à l’Internet notamment par l'intermédiaire des réseaux WiFi. La diversité et le nombre de déploiements sans coordination centrale (y compris les utilisateurs à leur domicile) conduit à des déploiements qu’on peut qualifier de chaotiques. En conséquence, les réseaux WiFi sont largement déployés avec une forte densité dans les zones urbaines. Dans ce contexte, les utilisateurs et les opérateurs tentent d’exploiter ces déploiements pour obtenir une connectivité omniprésente, et éventuellement d'autres services. Cependant, pour tirer parti de ces déploiements, il faut des stratégies pour identifier les réseaux utilisables et choisir les plus adaptés aux besoins. Pour cela, nous étudions le processus de découverte des réseaux dans le contexte de ces déploiements. Ensuite, nous présentons une plateforme de partage de mesures sans fil, un système d'information collaboratif où les stations mobiles recueillent des mesures du réseau et les envoient à un système central. En rassemblant mesures provenant de différents utilisateurs, la plateforme donne accès à des caractéristiques du déploiement précieuses. Nous évaluons l'utilité de cette plateforme collaborative grâce à deux applications : (1) l’ensemble minimal de points d'accès, afin de réduire l'énergie nécessaire pour offrir une couverture WiFi dans une zone donnée. (2) l'optimisation des paramètres de recherche de réseau, afin de réduire le temps nécessaire pour découvrir les réseaux existants. Ensuite, nous étudions une méthode passive pour déterminer si un réseau fonctionne dans un canal saturé. / Nowadays, mobile devices are present worldwide, with over 4.40 Billion devices globally. These devices enable users to access the Internet via wireless networks. Different actors (e.g., home users, enterprises) are installing WiFi networks everywhere, without central coordination, creating chaotic deployments. As a result, WiFi networks are widely deployed all over the world, with high accesspoint (AP) density in urban areas. In this context, end-users and operators are trying to exploit these dense network deployments to obtain ubiquitous Internet connectivity, and possibly other services. However, taking advantage of these deployments requires strategies to gather and provide information about the available networks. In this dissertation, we first study the network discovery process within the context of these deployments. Then, we present the Wireless Measurements Sharing Platform, a collaborative information system, to which mobile stations send simple network measurements that they collected. By gathering and processing several network measurements from different users, the platform provides access to valuable characteristics of the deployment. We evaluate the usefulness of this collaborative platform thanks to two applications: (1) the minimal access point set, to reduce the energy needed to offer WiFi coverage in a given area.(2) The optimization of the scanning parameters,to reduce the time a mobile station needs for the network discovery. Finally, we describe a method to identify whether an AP operates ina saturated channel, by passively monitoring beacon arrival distribution.