Hierarchical Wireless Sensor networks (WSNs) are becoming attractive to many applications due to their energy efficiency and scalability. However, if such networks are deployed in a privacy sensitive application context such as home utility consumption, protecting data privacy becomes an essential requirement. Our threat analysis in such networks has revealed that PPDA (Privacy Preserving Data Aggregation), NIDA (Node ID Anonymity) and ENCD (Early Node Compromise Detection) are three essential properties for protecting data privacy. The scope of this thesis is on protecting data privacy in hierarchical WSNs byaddressing issues in relation to two of the three properties identified, i.e., NIDA and ENCD, effectively and efficiently. The effectiveness property is achieved by considering NIDA and ENCD in an integrated manner, and the efficiency property is achieved by using an adaptive approach to security provisioning. To this end, the thesis has made the following four novel contributions. Firstly, this thesis presents a comprehensive analysis of the threats to data privacy and literature review of the countermeasures proposed to address these threats. The analysis and literature review have led to the identification of two main areas for improvements: (1) to reduce the resources consumed as the result of protecting data privacy, and (2) to address the compatibility issue between NIDA and ENCD.Secondly, a novel Adaptive Pseudonym Length Estimation (AdaptPLE) method has been proposed. The method allows the determination of a minimum acceptable length of the pseudonyms used in NIDA based on a given set of security and application related requirements and constraints. In this way, we can balance the trade-off between an ID anonymity protection level and the costs (i.e., transmission and energy) incurred in achieving the protection level. To demonstrate its effectiveness, we have evaluated the method by applying it to two existing NIDA schemes, the Efficient Anonymous Communication (EAC) scheme and theCryptographic Anonymous Scheme (CAS).Thirdly, a novel Adaptive Early Node Compromise Detection (AdaptENCD) scheme for cluster-based WSNs has been proposed. This scheme allows early detections of compromised nodes more effectively and efficiently than existing proposals. This is achieved by adjusting, at run-time, the transmission rate of heartbeat messages, used to detect nodes' aliveness, in response to the average message loss ratio in a cluster. This adaptive approach allows us to significantly reduce detection errors while keeping the number of transmitted heartbeat messages as low as possible, thus reducing transmission costs. Fourthly, a novel Node ID Anonymity Preserving Scheme (ID-APS) for clusterbased WSNs has been proposed. ID-APS protects nodes ID anonymity while, at the same time, also allowing the global identification of nodes. This later property supports the identification and removal of compromised nodes in the network, which is a significant improvement over the state-of-the-art solution, the CAS scheme. ID-APS supports both NIDA and ENCD by making a hybrid use of dynamic and global identification pseudonyms. More importantly, ID-APS achieves these properties with less overhead costs than CAS. All proposed solutions have been analysed and evaluated comprehensively to prove their effectiveness and efficiency.

In this research work we propose a 3D node deployment strategy by carefully considering the unique characteristics of underwater acoustic communication as well as 3D dynamic nature of UWSN. This strategy targets 3D UWSN and not only improves the routing protocol performance significantly in terms of end to end delay and energy consumption but also provides reliability in data transmission. This strategy has been developed step by step from a single line of vertical communication to an effective 3D node deployment for UWSN. Several simulation experiments were carried out after adding different features to the final design to observe their impact on the overall routing performance. Finally, it is verified that this design strategy improves the routing performance, provides reliability to the network and increases network lifetime. Furthermore, we compared our results to the random node deployment in 3D, which is commonly used for analysing the performance of UWSN routing protocols. The comparison results verified our effective deployment design and showed that it provides almost 150% less end-to-end delay and almost 25% less energy consumption to the random deployment. It also revealed that by increasing the data traffic, our 3D node deployment strategy has no loss of data due to several back-up paths available, which is in contrast to random node deployment, where the packet loss occurs by increasing the data traffic. Improving the routing performance by carefully analysing the impact of 3D node deployment strategy and ensuring full sensing, transmission and back-up coverage in a highly unpredictable underwater environment, is a novel approach. Embedding this strategy with any networking protocol will improve its performance significantly.

Em redes de sensores sem fio (RSSFs), o nó sorvedouro geralmente é a única entidade confiável. Uma RSSF desassistida é aquela na qual o nó sorvedouro está indisponível por um período de tempo, sendo necessário armazenar os dados coletados ao invés de transmiti-los para a entidade segura. Portanto, até o nó sorvedouro estar novamente disponível para a recepção dos dados, um adversário pode comprometer nós sensores distribuídos em uma região geográfica com o objetivo de encontrar e apagar determinadas unidades de dado. Com o objetivo de evitar este tipo de ataque, fornecendo sobrevivência de dados, estratégias geralmente utilizam confidencialidade e redundância de dados de forma que a agregação de dados por nós sensores seja inviável. Além disso, o decorrer do tempo permite que um adversário tenha maior poder de ataque através do comprometimento de diferentes conjuntos de nós sensores. Apresenta-se um protocolo de segurança para RSSFs desassistidas que, através da renovação do estado da rede, reduz a vantagem de um adversário em montar ataques a partir de dados obtidos com o decorrer do tempo. O mecanismo proposto fornece segurança para múltiplas unidades de dados e permite o uso de agregação de dados por nós sensores. Como forma de avaliação da proposta, foram realizados experimentos em nós sensores reais, além da elaboração de um modelo analítico e de simulações. Resultados indicam como usar o protocolo proposto em diferentes cenários para maximizar a sobrevivência de dados. Adicionalmente, apresenta-se a aplicabilidade do método proposto em cenários de redes heterogêneas, caso das redes de segurança pública, utilizando-se do paradigma de redes definidas por software (SDN) para implantação da rede. / In Wireless Sensor Networks, the base station is usually the only unconditionally trusted entity. If it is not connected for a period of time, the network is left unattended and sensor nodes cannot offload data in real time. Thus, until the base station becomes available, adversaries can compromise some sensor nodes and selectively destroy data. In order to prevent such attacks, providing the so-called data survival, strategies generally employ the use of cryptography in a scenario where decryption keys are exclusively in possession of the base station, which restricts the use of in-network aggregation. In addition, as time increases, mobile adversaries become stronger due to the ability of compromising different sets of nodes. We present a secure protocol that refreshes the state of the network and prevents adversaries from taking advantage of data obtained in prior rounds. The scheme provides security to multiple units of data and allows data aggregation to be performed by nodes. In order to evaluate the performance of the proposed scheme, we carried out measurements on real devices. We analyzed the security of the scheme analytically and through simulations. Results indicate increased time epochs before an adversary succeeds the attack, leading to more probability of data survival. We also apply our protocol to scenarios of heterogeneous networks, namely a public safety network scenario, which is deployed under the paradigm of software-defined networking (SDN).

Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-01-30T12:31:14Z No. of bitstreams: 1 PEDRO RINALDO CHAVES.pdf: 3607910 bytes, checksum: e6c9f208a2f52773a6226da6c4212ab9 (MD5) / Made available in DSpace on 2017-01-30T12:31:14Z (GMT). No. of bitstreams: 1 PEDRO RINALDO CHAVES.pdf: 3607910 bytes, checksum: e6c9f208a2f52773a6226da6c4212ab9 (MD5) Previous issue date: 2016-12-05 / The demand for wireless sensor networks (WSN) applied to industrial process monitoring and control should increase as the forth industrial revolution (Industry 4.0) gathers pace, since one if its main caracteristics is about flexible plant set-up. Flexibility and low cost make the WSN the perfect choice for the modern 21st century manufacturing plants. Small and medium enterprises (SMEs) have an important role in the development of the Latin America economies. This paper first describes the tests done in two industrial environments, analyses the results and examines the behaviour of a low cost, centralized WSN in industrial environments to ascertain the impact of the processes and environment (topology, distances, barriers, machines and people) in the radio signal and discuss the reliability and applicability of WSNs in process monitoring and control. The results obtained with the tests indicated a relationship between the received signal strength indicator (RSSI), the packet error rate (PER), the environment and the processes generating subsidies to the network management system. Subsequently, a new management strategy is presented, it includes two RSSI tracking indexes that guarantee an early warning in case the radio signal deteriorates. With the knowledge gathered, a set of best practices is presented; it covers the planning, installation and commissioning of centralized low cost WSNs for SMEs. / A demanda por redes de sensores sem fio (RSSF) aplicadas ? monitora??o e controle de processos em ambientes industriais de todos os tamanhos tende a aumentar ? medida que a quarta revolu??o industrial (Industry 4.0) avan?a, sendo que uma das suas caracter?sticas ? a flexibiliza??o da disposi??o dos equipamentos (plant set-up). A flexibilidade e baixo custo das RSSF as tornam a escolha perfeita para estas novas instala??es manufatureiras do s?culo 21. As pequenas e m?dias manufaturas (SMEs) tem um papel importante no desenvolvimento das economias da Am?rica Latina. Neste trabalho, primeiro descrevem-se os testes e analisa-se o comportamento de uma rede centralizada de sensores sem fio (RCSSF) de baixo custo, em dois ambientes industriais de m?dio porte de forma a se determinar como o ambiente (topologia, dist?ncias, barreiras, maquin?rio e pessoas) e os processos impactam o sinal de r?dio. Pondera-se tamb?m sobre a confiabilidade e aplicabilidade das RCSSF na monitora??o e controle de processos industriais que, por vezes, podem ser cr?ticos. Os resultados mostram uma rela??o entre par?metros como o indicador da intensidade do sinal recebido (RSSI), a taxa de erros do pacote (PER), o ambiente e os processos fornecendo assim subs?dios para a ger?ncia da rede. Posteriormente, apresenta-se uma nova estrat?gia de ger?ncia que consiste em dois ?ndices que rastreiam e monitoram o n?vel do RSSI garantindo um alerta precoce caso o sinal de r?dio apresente deteriora??o. Com os conhecimentos adquiridos, conclui-se o trabalho com a apresenta??o de um conjunto de melhores pr?ticas para auxiliar no planejamento, implanta??o e comissionamento de RCSSF de baixo custo voltadas ?s SMEs.

Wireless sensor networks are often battery powered and therefore their power consumption is of critical importance. Power requirements can be reduced by switching off radios when they are not needed and by using multi-hop communications to reduce the length of the radio links. Multi-hop communications however require message routing through the network. The Routing Protocol for lossy networks (RPL) has been designed by the Internet Engineering Task Force (IETF) for seamless integration of wireless sensor networks in the Internet. For switching on and off radios, radio duty cycling (RDC) protocols have been added to the traditional medium access control (MAC) protocols. Despite the fact they belong to different layers in the communications stack, it is intuitively clear that the choice of a specific RDC protocol for saving energy can influence the performances of RPL. Exploring experimentally this influence was the initial goal of this research. A 25 nodes wireless sensor network using Zolertia Z1 motes and the Contiki software was used for this investigation. Performance measurements without RDC protocol and with the three different RDC protocols readily available in Contiki were organized and the results of the experiments were compared. Unfortunately, with all three RDC protocols, serious malfunctions obscured the experimental results. Those malfunctions did not show up in absence of a RDC protocol and they could not be reproduced by our simulation studies. To tackle this issue, the behavior of the RDC protocols was scrutinized by means of experimental set-ups that eliminated as much as possible all non RDC related issues. Many, quite varied, malfunctions were discovered which all could have caused the observed RPL issues. Further research and better experimental set-ups made clear that all the discovered RDC malfunctions could be attributed to two real-world facts that were not considered by the implementers of the Contiki RDC protocols. The first cause is the small frequency difference between hardware real time clocks in stand-alone motes. The second is that the threshold built in the receiver to detect radio activity is much higher than the minimum level of signal that the same receiver can decode. Work-arounds have been designed for the observed malfunctions and they have been tested by means of a systematic comparison of the performance of the three modified RDC protocols. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Chen, Xijun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 72-77). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Design Challenges --- p.2 / Chapter 1.2 --- Wireless Sensor Network Applications --- p.6 / Chapter 1.2.1 --- Military Applications --- p.7 / Chapter 1.2.2 --- Environmental Applications --- p.9 / Chapter 1.2.3 --- Health Applications --- p.11 / Chapter 1.3 --- Wireless Biomedical Sensor Networks (WBSN) --- p.12 / Chapter 1.4 --- Text Organization --- p.13 / Chapter Chapter 2 --- Design a Wearable Platform for Wireless Biomedical Sensor Networks --- p.15 / Chapter 2.1 --- Objective --- p.17 / Chapter 2.2 --- Requirements for Wireless Medical Sensors --- p.19 / Chapter 2.3 --- Hardware design --- p.21 / Chapter 2.3.1 --- Materials and Methods --- p.21 / Chapter 2.3.2 --- Results --- p.24 / Chapter 2.3.3 --- Conclusion --- p.27 / Chapter 2.4 --- Software design --- p.28 / Chapter 2.4.1 --- TinyOS --- p.28 / Chapter 2.4.2 --- Software Organization --- p.28 / Chapter Chapter 3 --- Wireless Medical Sensors --- p.32 / Chapter 3.1 --- Sensing Physiological Information --- p.32 / Chapter 3.1.1 --- Pulse Oximetry --- p.32 / Chapter 3.1.2 --- Electrocardiograph --- p.36 / Chapter 3.1.3 --- Galvanic Skin Response --- p.41 / Chapter 3.2 --- Location Tracking --- p.43 / Chapter 3.2.1 --- Outdoor Location Tracking --- p.43 / Chapter 3.2.2 --- Indoor Location Tracking --- p.44 / Chapter 3.3 --- Motion Tracking --- p.49 / Chapter 3.3.1 --- Technology --- p.50 / Chapter 3.3.2 --- Motion Analysis Sensor Board --- p.51 / Chapter 3.4 --- Discussions --- p.52 / Chapter Chapter 4 --- Applications in Medical Care --- p.54 / Chapter 4.1 --- Introduction --- p.54 / Chapter 4.2 --- Wearable Wireless Body Area Network --- p.56 / Chapter 4.2.1 --- Architecture --- p.58 / Chapter 4.2.2 --- Deployment Scenarios --- p.62 / Chapter 4.3 --- Application in Ambulatory Setting --- p.63 / Chapter 4.3.1 --- Method --- p.64 / Chapter 4.3.2 --- The Software Architecture --- p.66 / Chapter Chapter 5 --- Conclusions and Future Work --- p.69 / References --- p.72 / Appendix --- p.78

Depuis ces deux dernières décennies, une nouvelle technologie sans fil appelée Réseau de Capteur Sans Fil (RCSF) résultant d"une fusion entre les systèmes embarqués et les communications sans fil a vu le jour. Un RCSF ("WSN : Wireless Sensor Network" en Anglais) est un réseau Ad hoc composé d"un grand nombre de nœuds qui sont des micro-capteurs qui peuvent être déployés de façon aléatoire ou déterministe dans une zone d"intérêt donnée. Ces nœuds capteurs sont capables de récolter plusieurs paramètres physiques sur l"environnement qui les entoure, appelé généralement zone de captage (ou zone de surveillance). Ensuite, ils doivent si nécessaire traiter les données capturées et les transmettre à un (ou plusieurs) nœud de collecte appelé station de base, centre de traitement ("sink" en Anglais). Beaucoup de domaines d"applications tels que le contrôle et suivi environnemental, le contrôle de production dans l"industrie, la surveillance de zone, le monitoring de l"habitat, l"agriculture intelligente, etc. sont basés sur les RCSF. Toutefois, les RCSF ne sont pas parfaits. En effet, compte tenu de leur petite taille, leur faible coût et leurs déploiement dans des zones souvent hostiles ou difficiles d"accès, les nœuds capteurs présentent un certain nombre de faiblesses parmi lesquelles une durée de vie du réseau limitée, une bande passante faible, des capacités de capture et de communication réduites, etc. Afin de surmonter ces contraintes des RCSF, plusieurs problématiques de recherche sont nées ces dernières années, et les principales portent sur l"optimisation de la consommation énergétique en vue d"améliorer la durée de vie du réseau. D"autres recherches importantes menées dans le domaine de ces réseaux portent sur les stratégies de placement des nœuds, sur la couverture de zones et sur la connectivité du réseau. Cependant, la plupart des solutions proposées ces dernières années ne prennent pas en compte toutes ces problématiques dans leurs modèles de résolution ; alors que dans beaucoup d"applications des RCSF telles que la surveillance de zone critique, le monitoring de l"habitat, l"agriculture intelligente, il est nécessaire de garantir en même temps une couverture complète de la zone de surveillance, une bonne connectivité du réseau, tout en optimisant au mieux la durée de vie de celui-ci. Le but de cette thèse est donc de proposer de nouveaux mécanismes efficaces pour l"optimisation de la durée de vie dans les RCSF, tout en garantissant, à tout moment de cette durée de vie, une couverture totale de la zone de surveillance, ainsi qu"une bonne connectivité du réseau. Pour atteindre nos objectifs, nous avons étudié et fait des propositions dans deux axes qui sont le placement des nœuds et les mécanismes d"ordonnancement au niveau de la couche MAC. Pour ces derniers, nous avons mis en place un algorithme appelé DSMAC (Distributed Scheduling Medium Acces Control) qui est basé sur notre méthode de placement des nœuds. Par ailleurs, DSMAC permet de couvrir 100% de la zone de surveillance, assure une bonne connectivité du RCSF et permet également aux nœuds capteurs d"économiser jusqu"à 30% de leur énergie comparativement à d"autres protocoles MAC tels que TunableMAC. / Since the past two decades, a new technology called Wireless Sensor Network (WSN) which result in a fusion of embedded systems and wireless communications has emerged. A WSN is Ad hoc network composed of many sensors nodes communicating via wireless links and which can be deployed randomly or deterministically over a given interest region. Theses sensors can also collect data from the environment, do local processing and transmit the data to a sink node or Base Station (BS) via multipath routing. Thereby, a wide range of potential applications have been envisioned using WSN such as environmental conditions monitoring, wildlife habitat monitoring, industrial diagnostic, agricultural, improve health care, etc. Nevertheless,WSN are not perfect. Indeed, given their small size, their low cost and their deployment generally in hostile or difficult access areas, sensor nodes have some weaknesses such as: a limited energy, so a network lifetime limited, limited bandwidth, limited computations and communications capabilities, etc. To overcome these limitations, several research issues from were created in recent years, and the main issues focus on the optimization of energy consumption in order to improve the network lifetime. Other important researches focus on issues of coverage areas, placement strategies of sensor nodes and network connectivity. However, most solutions proposed in recent years to resolve these issues do not take into account all these issues that we cited above in resolutions models; while in many WSN applications such as monitoring critical region, wildlife habitat monitoring, agricultural application, a full coverage of the monitoring region and network connectivity are mandatory as well an energy-awareness network lifetime. The objective of this thesis is thus to propose new scheduling mechanisms for optimizing the network lifetime in WSN, while ensuring at any time of the network lifetime a full coverage of the monitored region and network connectivity. To achieve our goals, we have study and done proposal in two axes which are placement strategy of sensor nodes and scheduling mechanism in the MAC layer. For these, we have implemented a Distributed Scheduling Medium Access Control algorithm (DSMAC) based on our placement method. Furthermore, DSMAC enables to cover 100% of the monitored region, to ensure optimal network connectivity and also allows sensors node to save up to 30% of their energy compared to other MAC protocols such as TunableMAC.

Healthcare associated infections are a considerable burden to the health care system. The affected patients have their prognosis worsened and demand more resources from hospitals. Furthermore, the bacteria causing these infections are becoming increasingly resistant to antibiotics while also becoming more deadly and contagious. Contributing with knowledge for stopping these infections is, therefore, important. This thesis reports on two projects centered on data collected at the University of Iowa Hospital and Clinics. The first project consisted in analyzing data collected by sensors that reported the location and hand washing behavior of health care workers. After extracting meaning from these radio signals, I studied two socially and epidemiologically relevant tasks: the inference of contact networks, which can be used to study the spread of infections in the hospital, and the study of associations between social pressure and hand washing, learning that effectively workers in proximity to others wash their hands more, but also that not all workers are as influential. In the second project, I developed a data mining method for analyzing medical records aimed at tackling the problems of class imbalance and high dimensionality, and applied it to predicting Clostridium Difficile infection. The learnt models performed better than the state of the art and even improved prediction as the onset of symptoms approached. The main contribution, however, was in the information discovered: certain events in certain orders increased the risk of developing the infection, suggesting that reversing these orders could improve prognosis.

Success of Wireless Sensor Networks (WSN) largely depends on whether the deployed network can provide desired area coverage with acceptable network lifetime. In hostile or harsh environments such as enemy territories in battlefields, fire or chemical spills, it is impossible to deploy the sensor nodes in a predeter- mined regular topology to guarantee adequate coverage. Random deployment is thus more practical and feasible for large target areas. On the other hand, random deployment of sensors is highly susceptible to the occurrence of coverage holes in the target area. A potential solution for enhancing the existing coverage achieved by random deployments involves the use of mobility capable sensors that would help fill the coverage holes. This thesis seeks to address the problem of determining the current coverage achieved by the non-deterministic deployment of static sensor nodes and subsequently enhancing the coverage using mobile sensors. The main contributions of this dissertation are the design and evaluation of MAPC (Mobility Assisted Probabilistic Coverage), a distributed protocol for ensuring area coverage in hybrid wireless sensor networks. The primary contribution is a pragmatic approach to sensor coverage and maintenance that we hope would lower the technical barriers to its field deployment. Most of the assumptions made in the MAPC protocol are realistic and implementable in real-life applications e.g., practical boundary estimation, coverage calculations based on a realistic sensing model, and use of movement triggering thresholds based on real radio characteristics etc. The MAPC is a comprehensive three phase protocol. In the first phase, the static sensors calculate the area coverage using the Probabilistic Coverage Algorithm (PCA). This is a deviation from the idealistic assumption used in the binary detection model, wherein a sensor can sense accurately within a well defined (usually circular) region. Static sensors execute the PCA algorithm, in a distributed way, to identify any holes in the coverage. In the second phase, MAPC scheme moves the mobile nodes in an optimal manner to fill these uncovered locations. For different types of initial deployments, the proposed movement algorithms consume only 30-40% of the energy consumed by the basic virtual force algorithm. In addition, this thesis addresses the problem of coverage loss due to damaged and energy depleted nodes. The problem has been formulated as an Integer Linear Program and implementable heuristics are developed that perform close to optimal solutions. By replacing in-operational nodes in phase three, MAPC scheme ensures the continuous operation of the WSN. Experiments with real mote hardware were conducted to validate the boundary and coverage estimation part of the MAPC protocol. Extensive discrete event simulations (using NS2) were also performed for the complete MAPC protocol and the results demonstrate that MAPC can enhance and maintain the area coverage by efficiently moving mobile sensor nodes to strategic positions in the uncovered area.

It is widely accepted that low energy consumption is the most important requirement when designing components and systems for a wireless sensor network (WSN). The greatest energy consumer of each node within a WSN is the radio transceiver and as such, it is important that this component be used in an extremely energy e±cient manner. One method of reducing the amount of energy consumed by the radio transceiver is to turn it off and allow nodes to enter a sleep mode. The algorithms that directly control the radio transceiver are traditionally grouped into the Medium Access Control (MAC) layer of a communication protocol stack. This thesis introduces the emerging field of wireless sensor networks and outlines the requirements of a MAC protocol for such a network. Current MAC protocols are reviewed in detail with a focus on how they utilize this energy saving sleep mode as well as performance problems that they suffer from. A proposed new method of coordinating the use of this sleep mode between nodes in the network is specifed and described. The proposed new protocol is analytically compared with existing protocols as well as with some fundamental performance limits. The thesis concludes with an analysis of the results as well as some recommendations for future work.